WO2017138521A1

WO2017138521A1 - Conductive particles, conductive material and connected structure

Info

Publication number: WO2017138521A1
Application number: PCT/JP2017/004388
Authority: WO
Inventors: 悠人土橋; 昌男笹平
Original assignee: 積水化学工業株式会社
Priority date: 2016-02-08
Filing date: 2017-02-07
Publication date: 2017-08-17
Also published as: CN111508635A; TW201740390A; JP6386163B2; CN111508635B; KR102685922B1; JP2019012692A; KR20180109832A; TWI703584B; CN107851482B; CN107851482A; JPWO2017138521A1

Abstract

Provided are conductive particles which are capable of suppressing corrosion of a conductive layer that contains nickel even in the presence of either an acid or an alkali. Each conductive particle according to the present invention comprises a base particle and a conductive layer that is arranged on the surface of the base particle and contains nickel. The conductive layer containing nickel is an alloy layer containing at least one metal selected from among nickel, tin and indium; and the average total content of tin and indium in 100% by weight of a region of the conductive layer containing nickel from the outer surface to 1/2 of the depth thereof is less than 5% by weight.

Description

Conductive particles, conductive materials, and connection structures

The present invention relates to conductive particles in which a conductive layer containing nickel is disposed on the surface of base particles. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

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

For example, when the semiconductor chip electrode and the glass substrate electrode are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

As an example of the conductive particles, the following Patent Document 1 discloses conductive particles having base particles and a conductive metal layer covering the surface of the base particles. Specific examples of the metal constituting the conductive metal layer include nickel, nickel alloys (Ni—Au, Ni—Pd, Ni—Pd—Au, Ni—Ag, Ni—P, Ni—B, Ni—Zn, Ni—Sn, Ni—W, Ni—Co, Ni—Ti); copper, copper alloy (Cu and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, An alloy with at least one metal element selected from the group consisting of Ir, Ag, Au, Bi, Al, Mn, Mg, P, B, preferably an alloy with Ag, Ni, Sn, Zn); silver, Silver alloy (from the group consisting of Ag and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Au, Bi, Al, Mn, Mg, P, B An alloy with at least one selected metal element, preferably Ag-Ni, g—Sn, Ag—Zn); tin, tin alloy (eg, Sn—Ag, Sn—Cu, Sn—Cu—Ag, Sn—Zn, Sn—Sb, Sn—Bi—Ag, Sn—Bi—In, Sn) -Au, Sn-Pb, etc.).

The following Patent Document 2 discloses conductive particles in which a metal coating layer is formed on the surface of resin particles. The metal coating layer is formed by an electroless nickel plating process using a boron compound and a hypophosphite compound as a reducing agent. Patent Document 2 describes that the metal coating layer may contain other metal that co-deposits with nickel in addition to nickel, boron, and phosphorus. Other metals that co-deposit with nickel include cobalt, copper, zinc, iron, manganese, chromium, vanadium, molybdenum, palladium, tin, indium, tungsten and rhenium.

Patent Document 3 below discloses conductive particles including base particles and a conductive layer containing nickel disposed on the surface of the base particles. The conductive layer is an alloy layer containing nickel and tin. In 100% by weight of the entire conductive layer, the average content of tin is 5% by weight or more and 50% by weight or less.

JP 2013-125649 A JP 2008-41671 A JP 2015-130328 A

When conventional conductive particles as described in

Patent Documents

1 and 2 are exposed to the presence of an acid, corrosion of the conductive layer containing nickel may occur. Further, when conventional conductive particles as described in Patent Documents 1 to 3 are exposed to the presence of alkali, corrosion of the conductive layer containing nickel may occur. In addition, when a connection structure is obtained by connecting electrodes using conventional conductive particles, the connection resistance between the electrodes increases when the connection structure is exposed to the presence of acid or alkali. There are things to do. Furthermore, if the average content of tin in the conductive layer containing nickel increases, the specific resistance of the conductive layer tends to increase and the conductive layer tends to become brittle. Cracking is likely to occur.

An object of the present invention is to provide conductive particles capable of suppressing corrosion of a conductive layer containing nickel in the presence of either acid or alkali.

Another object of the present invention is to provide a conductive material and a connection structure using the conductive particles.

According to a wide aspect of the present invention, the substrate includes a base particle and a conductive layer that is disposed on a surface of the base particle and includes nickel, and the conductive layer including nickel includes nickel, tin, and indium. An alloy layer containing at least one of the above, and an average content of tin and indium in 100% by weight of the region from the outer surface of the conductive layer containing nickel to a thickness of 1/2 inward. Conductive particles are provided that are less than 5% by weight.

In a specific aspect of the conductive particles according to the present invention, the total average content of tin and indium in the region from the outer surface of the conductive layer containing nickel to a thickness of ¼ toward the inside is the nickel. More than the total average content of tin and indium in the region from the position of the thickness ¼ to the position of the thickness ½ from the outer surface to the inner side of the conductive layer.

In a specific aspect of the conductive particles according to the present invention, the total content of tin and indium in 100% by weight of the region from the outer surface to the inner side of the nickel-containing conductive layer to a thickness of 1/4. The maximum value of is 50% by weight or less.

In a specific aspect of the conductive particle according to the present invention, the conductive layer containing nickel has a protrusion on the outer surface.

In a specific aspect of the conductive particles according to the present invention, the volume resistivity is 0.003 Ω · cm or less.

In a specific aspect of the conductive particles according to the present invention, the average content of tin and indium in 100% by weight of the region from the inner surface to the outer side of the nickel-containing conductive layer to a thickness of 1/2. The amount is less than 5% by weight.

In a specific aspect of the conductive particle according to the present invention, the conductive particle further includes an insulating substance disposed on an outer surface of the conductive layer containing nickel.

According to a wide aspect of the present invention, there is provided a conductive material including the above-described conductive particles and a binder resin.

According to a wide aspect of the present invention, the first connection target member, the second connection target member, the connection portion connecting the first connection target member, and the second connection target member; There is provided a connection structure in which the material of the connection portion is the above-described conductive particles or a conductive material containing the conductive particles and a binder resin.

The conductive particles according to the present invention include base particles and a conductive layer that is disposed on the surface of the base particles and includes nickel, and the conductive layer including nickel is made of nickel, tin, and indium. The total content of tin and indium in 100% by weight of the region from the outer surface of the conductive layer containing nickel to the thickness ½ in the alloy layer. Is less than 5% by weight, the corrosion of the conductive layer containing nickel can be suppressed even in the presence of either acid or alkali.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. 4A and 4B are schematic diagrams for explaining each region for obtaining the total average content of tin and indium in a conductive layer containing nickel. FIG. 5 is a front sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

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

(Conductive particles)
The electroconductive particle which concerns on this invention is equipped with the base material particle and the electroconductive layer which is arrange | positioned on the surface of this base material particle and contains nickel.

In the conductive particles according to the present invention, the conductive layer containing nickel is an alloy layer containing nickel and at least one of tin and indium. In the conductive particles according to the present invention, the total average content of tin and indium is 5% by weight in 100% by weight of the region from the outer surface of the conductive layer containing nickel to the thickness ½ toward the inside. Is less than.

The conductive particles may be exposed to acid or alkali conditions by acidic gas or alkaline gas in the atmosphere, acidic components or alkaline components other than the conductive particles contained in the conductive material, and the like.

By adopting the above-described configuration in the conductive particles according to the present invention, corrosion of the conductive layer containing nickel can be suppressed in the presence of either acid or alkali. Even when the conductive particles are exposed to the presence of an acid or an alkali, corrosion of the conductive layer containing nickel is unlikely to occur, so that the performance as the conductive particles can be maintained high. In the present invention, corrosion of the conductive layer containing nickel in the presence of an alkali can be further suppressed while suppressing corrosion of the conductive layer containing nickel even in the presence of an acid.

Moreover, since corrosion of the conductive layer containing nickel can be suppressed, when the connection structure is obtained by electrically connecting the electrodes with the conductive particles according to the present invention, the conductivity before the connection between the electrodes is obtained. Even when the conductive particles are exposed to the presence of an acid or an alkali, the connection resistance can be kept low. Moreover, since the corrosion of the conductive layer containing nickel can be suppressed, the connection resistance can be kept low even when the connection structure is exposed to the presence of an acid or an alkali.

Furthermore, the connection reliability between the electrodes under high humidity can be improved by adopting the above-described configuration in the conductive particles according to the present invention. Furthermore, by adopting the above-described configuration in the conductive particles according to the present invention, aggregation of the conductive particles can be suppressed. By suppressing the aggregation of the conductive particles, the connection resistance between the electrodes can be effectively reduced.

Furthermore, in the electroconductive particle which concerns on this invention, since the electroconductive layer containing nickel contains at least 1 sort (s) of tin and indium, the strong magnetism of nickel can be suppressed and the effect which suppresses aggregation by magnetism is acquired. . For this reason, a plurality of conductive particles can be efficiently arranged on the electrode. Therefore, when the electrodes are electrically connected, the connection reliability and conduction reliability between the electrodes can be further enhanced. Furthermore, electrical connection between laterally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be further improved. Further, the conductive particles according to the present invention have a total average content of 5% by weight of tin and indium in 100% by weight of the region from the outer surface of the conductive layer containing nickel to the thickness ½ toward the inside. Therefore, the conductive layer is hardly brittle and the conductive layer is hardly corroded in the presence of an acid or an alkali. Therefore, aggregation of conductive particles accompanying the corrosion reaction of the conductive layer can be suppressed.

From the viewpoint of further improving the connection reliability between the electrodes, the total average content of tin and indium is preferably 1% by weight or more, more preferably 2% by weight or more, in 100% by weight of the entire conductive layer containing nickel. , Preferably 5% by weight or less, more preferably less than 5% by weight.

Further, when the total average content of tin and indium is 5% by weight or less in 100% by weight of the entire conductive layer containing nickel, the conductive layer tends to be difficult to become brittle. Therefore, when the total content of tin and indium is 5% by weight or less in 100% by weight of the entire conductive layer containing nickel, the corrosion of the conductive layer in the presence of acid or alkali is further caused. The connection resistance after being exposed to the presence of an acid or an alkali can be maintained even more effectively. Further, in the case where the total content of tin and indium is 5% by weight or less in 100% by weight of the entire conductive layer containing nickel, the specific resistance of the conductive layer tends to be difficult to increase, and between the electrodes Since the conductive layer is less likely to crack due to compression at the time of connection, the connection resistance can be more effectively maintained low.

From the viewpoint of further improving the adhesion between the base particles and the conductive layer containing nickel and further improving the connection reliability between the electrodes, the thickness from the inner surface of the conductive layer containing nickel to the thickness ½ is increased. In 100% by weight of the region (R1), the total average content of tin and indium is preferably 5% by weight or less, more preferably less than 5% by weight, still more preferably 3% by weight or less, particularly preferably 2% by weight. It is as follows. The region (R1) is a region inside the broken line L1 of the conductive layer 3 containing nickel in FIG.

The total content of tin and indium is less than 5% by weight in 100% by weight of the region (R2) from the outer surface of the conductive layer containing nickel to the thickness ½ toward the inside. From the viewpoint of further improving the connection reliability between the electrodes, 100% of the region (R2) from the outer surface of the conductive layer containing nickel to the thickness ½ in 100% by weight of the total conductive layer containing nickel. In the weight%, the total average content of tin and indium is preferably 3% by weight or less, more preferably 2% by weight or less. The region (R2) is a region outside the broken line L1 of the conductive layer 3 containing nickel in FIG.

The total average content of tin and indium in the region (R1) may be less than the total average content of tin and indium in the region (R2), and tin and indium in the region (R2). May be the same as the total average content, and may be greater than the total average content of tin and indium in the region (R2).

From the viewpoint of further improving the adhesion between the base material particles and the conductive layer containing nickel, further improving the connection reliability between the electrodes, and further suppressing the corrosion of the conductive particles due to acid or alkali, the above region (R1 The total average content of tin and indium in () is preferably smaller than the total average content of tin and indium in the region (R2).

From the viewpoint of further improving the adhesion between the base material particles and the conductive layer containing nickel and further improving the connection reliability between the electrodes, the thickness of the conductive layer containing nickel is ¼ from the outer surface to the inside. In 100% by weight of the region (R3), the total average content of tin and indium is preferably 20% by weight or less, more preferably 10% by weight or less. The region (R3) is a region outside the broken line L2 of the conductive layer 3 containing nickel in FIG.

Position of 1/4 thickness from the outer surface of the conductive layer containing nickel to the inside from the viewpoint of further improving the adhesion between the substrate particles and the conductive layer containing nickel and further improving the connection reliability between the electrodes. The total content of tin and indium is preferably 10% by weight or less, more preferably 1% by weight or less, in 100% by weight of the region (R4) from the position to the position of the thickness 1/2. The region (R4) is a region between the broken line L1 and the broken line L2 of the conductive layer 3 containing nickel in FIG.

From the viewpoint of further improving the adhesion between the substrate particles and the conductive layer containing nickel, further improving the connection reliability between the electrodes, and further suppressing the corrosion of the conductive particles due to acid or alkali, the region (R3 The total average content of tin and indium in () is preferably larger than the total average content of tin and indium in the region (R4).

In the region (R3), tin and indium may not be uniformly distributed when the region (R3) is viewed as a whole. The region (R3) may have a portion having a relatively large total content of tin and indium and a portion having a relatively small total content of tin and indium. In the region (R3), there may be a variation in the total content of tin and indium. From the viewpoint of further improving the adhesion between the substrate particles and the conductive layer containing nickel, further improving the connection reliability between the electrodes, and further suppressing the corrosion of the conductive particles due to acid or alkali, the region (R3 The maximum value of the total content of tin and indium is preferably 5% by weight or more, more preferably 10% by weight or more, preferably 50% by weight or less, more preferably 45% by weight. It is as follows. The maximum value of the total content of tin and indium indicates the content at the position where the total content of tin and indium is the highest in the region (R3).

The maximum value of the total content of tin and indium in 100% by weight of the region (R3) can be measured as follows.

Using a focused ion beam, make a thin film slice of the conductive particles obtained. Content of nickel, tin, and indium in the thickness direction of the conductive layer containing nickel by using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by JEOL Ltd.) with an energy dispersive X-ray analyzer (EDS) By measuring, a distribution result of the contents of nickel, tin and indium in the thickness direction of the conductive layer containing nickel can be obtained. From this result, the maximum value of the total content of tin and indium in 100% by weight of the region (R3) can be obtained.

In the conductive particles according to the present invention, the melting point of the conductive layer containing nickel is preferably 300 ° C. or higher. A conductive layer having a melting point of 300 ° C. or higher and generally containing nickel has a small average content of tin, so that it is different from a solder layer generally called solder and different from a solder layer having a low melting point. The upper limit of the melting point of the conductive layer containing nickel is not particularly limited. The melting point of the conductive layer containing nickel may be 3000 ° C. or lower, 2000 ° C. or lower, or 1000 ° C. or lower. The melting point of the conductive layer containing nickel may be 400 ° C. or higher, or may be 500 ° C. or higher.

From the viewpoint of further reducing the connection resistance and further improving the connection reliability between the electrodes, the compression elastic modulus (10% K value) when the conductive particles are compressed by 10% is preferably 10 N / mm ^2. or more, more preferably 50 N / mm ² or more, preferably 4000 N / mm ² or less, and more preferably not more than 3000N / mm ^2.

The compression elastic modulus (10% K value) of the conductive particles can be measured as follows.

Using a micro-compression tester, the conductive particles are compressed on a cylindrical indenter end face (diameter 50 μm, made of diamond) under conditions of applying a maximum test load of 90 mN over 30 seconds at 25 ° C. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 10% compressively deformed (N)
S: Compression displacement (mm) when the conductive particles are 10% compressively deformed
R: radius of conductive particles (mm)

The above-mentioned compression elastic modulus universally and quantitatively represents the hardness of the conductive particles. By using the compression elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

From the viewpoint of further suppressing the aggregation of the conductive particles and further effectively reducing the connection resistance between the electrodes, the volume resistivity of the conductive particles is preferably 0.003 Ω · cm or less.

Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention.

1 has a base particle 2 and a conductive layer 3 containing nickel. The conductive layer 3 is disposed on the surface of the base particle 2. In the first embodiment, the conductive layer 3 is in contact with the surface of the base particle 2. The conductive particle 1 is a coated particle in which the surface of the base particle 2 is coated with the conductive layer 3.

In the conductive particles 1, the conductive layer 3 containing nickel is a single conductive layer. In the conductive particles 1, the conductive layer 3 containing nickel is an alloy layer containing nickel and at least one of tin and indium. The total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the outer surface to the thickness 1/2 of the conductive layer 3 containing nickel.

Unlike the

conductive particles

11 and 21 described later, the conductive particles 1 do not have a core substance. The conductive particles 1 do not have protrusions on the surface. The conductive particles 1 are spherical. The conductive layer 3 has no protrusion on the outer surface. Thus, the electroconductive particle which concerns on this invention does not need to have a processus | protrusion on the electroconductive surface, and may be spherical. Moreover, the electroconductive particle 1 does not have an insulating substance unlike the

electroconductive particles

11 and 21 mentioned later. However, the conductive particles 1 may have an insulating material disposed on the outer surface of the conductive layer 3. In this case, a conductive layer not containing nickel may be disposed between the conductive layer 3 and the insulating material.

In the conductive particle 1, the base particle 2 and the conductive layer 3 containing nickel are in contact. A conductive layer not containing nickel may be disposed between the base particle and the conductive layer containing nickel, and the conductive layer not containing nickel is arranged on the outer surface of the conductive layer containing nickel. May be.

FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention.

The conductive particles 11 shown in FIG. 2 have base material particles 2, a conductive layer 12 containing nickel, a plurality of core substances 13, and a plurality of insulating substances 14. The conductive layer 12 containing nickel is disposed on the surface of the base particle 2 so as to be in contact with the base particle 2.

In the conductive particles 11, the conductive layer 12 containing nickel is a single conductive layer. In the conductive particles 11, the conductive layer 12 containing nickel is an alloy layer containing nickel and at least one of tin and indium. The total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the outer surface to the thickness ½ of the conductive layer 12 containing nickel inward.

The conductive particles 11 have a plurality of protrusions 11a on the conductive surface. The conductive layer 12 containing nickel has a plurality of protrusions 12a on the outer surface. A plurality of core substances 13 are arranged on the surface of the base particle 2. The plurality of core materials 13 are embedded in the conductive layer 12 containing nickel. The core substance 13 is disposed inside the protrusions 11a and 12a. The conductive layer 12 containing nickel covers a plurality of core substances 13. The outer surface of the conductive layer 12 containing nickel is raised by a plurality of core materials 13 to form protrusions 11a and 12a.

The conductive particles 11 have an insulating material 14 disposed on the outer surface of the conductive layer 12 containing nickel. At least a partial region of the outer surface of the conductive layer 12 containing nickel is covered with an insulating material 14. The insulating substance 14 is made of an insulating material and is an insulating particle. Thus, the electroconductive particle which concerns on this invention may have the insulating substance arrange | positioned on the outer surface of an electroconductive layer. However, the conductive particles according to the present invention do not necessarily have an insulating substance.

FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention.

The conductive particle 21 shown in FIG. 3 has the base particle 2, the conductive layer 22 containing nickel, a plurality of core materials 13, and a plurality of insulating materials 14. The conductive layer 22 containing nickel as a whole has a first conductive layer 22A on the base particle 2 side and a second conductive layer 22B on the opposite side to the base particle 2 side.

The conductive particles 11 and the conductive particles 21 are different only in the conductive layer. That is, in the conductive particles 11, the conductive layer 12 having a single-layer structure is formed, whereas in the conductive particles 21, the first conductive layer 22A and the second conductive layer 22B having a two-layer structure are formed. ing. The first conductive layer 22A and the second conductive layer 22B are formed as separate conductive layers.

The first conductive layer 22A is disposed on the surface of the base particle 2. 22 A of 1st conductive layers are arrange | positioned between the base particle 2 and the 2nd conductive layer 22B. The first conductive layer 22A is in contact with the base particle 2. The second conductive layer 22B is in contact with the first conductive layer 22A. Accordingly, the first conductive layer 22A is disposed on the surface of the base particle 2, and the second conductive layer 22B is disposed on the surface of the first conductive layer 22A. The conductive particles 21 have a plurality of protrusions 21a on the conductive surface. The conductive layer 22 has a plurality of protrusions 22a on the outer surface. The first conductive layer 22A has a plurality of protrusions 22Aa on the outer surface. The second conductive layer 22B has a plurality of protrusions 22Ba on the outer surface.

In the conductive particles 21, the conductive layer 22 containing nickel is a two-layer conductive layer. In the conductive particles 21, the conductive layer 22 containing nickel is an alloy layer containing nickel and at least one of tin and indium. Accordingly, the first conductive layer 22A and the second conductive layer 22B are alloy layers each including nickel, at least one of tin and indium. The total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the outer surface to the thickness ½ toward the inside from the outer surface of the conductive layer 22 containing nickel.

Hereinafter, other details of the conductive particles will be described.

(Base particle)
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particle may have a core and a shell disposed on the surface of the core, or may be a core-shell particle. The core may be an organic core, and the shell may be an inorganic shell.

The base material particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. When connecting between electrodes using the said electroconductive particle, after arrange | positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping | bonding. When the substrate particles are resin particles or organic-inorganic hybrid particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes can be improved further.

Various organic substances are suitably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate , Polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide , Polyacetal, polyimide, polyamideimide, polyether ether Tons, polyether sulfone, divinyl benzene polymer, and divinylbenzene copolymer, and the like. Examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene- (meth) acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled within a suitable range, the resin for forming the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. It is preferably a coalescence.

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

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

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

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

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

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 core is preferably an organic core. The shell is preferably an inorganic shell. From the viewpoint of effectively reducing the connection resistance between the electrodes, the base material particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Examples of the material for forming the organic core include the resin for forming the resin particles described above.

Examples of the material for forming the inorganic shell include inorganic substances for forming the above-described base material particles. The material for forming the inorganic shell is preferably silica. The inorganic shell is preferably formed on the surface of the core by forming a metal alkoxide into a shell by a sol-gel method and then sintering the shell. The metal alkoxide is preferably a silane alkoxide. The inorganic shell is preferably formed of a silane alkoxide.

The particle size of the core is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. It is. When the particle size of the core is not less than the above lower limit and not more than the above upper limit, more suitable conductive particles can be obtained by electrical connection between the electrodes, and the base particles can be suitably used for the use of conductive particles. Become. For example, when the core particle size is not less than the lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, and It is possible to make it difficult to form aggregated conductive particles when forming the conductive portion. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portion can be made difficult to peel from the surface of the substrate particles.

The particle diameter of the core means a diameter when the core is a true sphere, and means a maximum diameter when the core is a shape other than a true sphere. Moreover, the particle size of a core means the average particle size which measured the core with the arbitrary particle size measuring apparatus. For example, a particle size distribution measuring machine using principles such as laser light scattering, electrical resistance value change, and image analysis after imaging can be used.

The thickness of the shell is preferably 100 nm or more, more preferably 200 nm or more, 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 base particles can be suitably used for the use of conductive particles. . The thickness of the shell is an average thickness per base particle. The thickness of the shell can be controlled by controlling the sol-gel method.

When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles, and preferably not copper 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, preferably 1000 μm or less, more preferably 500 μm or less, more More preferably, it is 300 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. When the particle diameter of the base material particles is equal to or larger than the lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes can be further improved and the connection is made through the conductive particles. The connection resistance between the formed electrodes can be further reduced. Further, when the conductive layer is formed on the surface of the substrate particles by electroless plating, the aggregated conductive particles can be made difficult to be formed. When the particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes can be further reduced, and the interval between the electrodes can be further reduced. it can.

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

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 to 5 μm, the distance between the electrodes can be further reduced, and even when the thickness of the conductive layer is increased, small conductive particles can be obtained. .

(Conductive layer)
The electroconductive particle which concerns on this invention is equipped with the electroconductive layer containing the nickel arrange | positioned on the surface of base material particle and base material particle. The conductive layer containing nickel contains nickel and at least one of tin and indium. The total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the outer surface to the thickness ½ toward the inside from the outer surface of the conductive layer containing nickel. The conductive layer containing nickel may be referred to as the conductive layer X in the following (conductive layer) column. The conductive layer X does not include a conductive layer that does not include nickel, and does not include a conductive layer portion that does not include nickel.

From the viewpoint of effectively increasing the conductivity, it is better that the average content of nickel is larger in 100% by weight of the entire conductive layer X. Therefore, the average content of nickel is preferably 50% by weight or more, more preferably 65% by weight or more, still more preferably 70% by weight or more, and still more preferably 80% by weight or more in the total 100% by weight of the conductive layer X. Even more preferably, it is 85% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more. In 100% by weight of the entire conductive layer X, the average nickel content is preferably 99% by weight or less, more preferably 98% by weight or less, and still more preferably 97% by weight or less. When the average content of nickel is not less than the above lower limit, the connection resistance between the electrodes can be further reduced. Moreover, when there are few oxide films in the surface of an electrode or a conductive layer, there exists a tendency for the connection resistance between electrodes to become low, so that there is much average content of nickel.

The method for measuring the contents of nickel, tin and indium in the conductive layer containing nickel (conductive layer X) is not particularly limited, and various known analytical methods can be used. It can be measured using a high-frequency inductively coupled plasma emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu).

The contents of nickel, tin, and indium in each region in the thickness direction of the conductive layer X can be measured using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by JEOL Ltd.).

The total thickness of the conductive layer X is preferably 0.005 μm or more, more preferably 0.01 μm or more, still more preferably 0.05 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. When the total thickness of the conductive layer X 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 do not become too hard, and the conductive particles are connected at the time of connection between the electrodes. Can be sufficiently deformed.

The total thickness of the conductive layer X is particularly preferably 0.05 μm or more and 0.3 μm or less. Furthermore, it is particularly preferable that the particle diameter of the base material particle is 2 μm or more and 5 μm or less, and the total thickness of the conductive layer X is 0.05 μm or more and 0.3 μm or less. In this case, the conductive particles can be suitably used for applications in which a large current flows. Further, when the conductive particles are compressed to connect the electrodes, it is possible to further suppress the electrodes from being damaged.

The thickness of the conductive layer X can be measured by observing the cross section of the conductive particles using, for example, a transmission electron microscope (“JEM-2100” manufactured by JEOL Ltd.).

The conductive layer X may contain a metal other than nickel, tin and indium. Examples of the metal other than nickel, tin, and indium in the conductive layer X include, for example, gold, silver, copper, platinum, zinc, iron, lead, aluminum, cobalt, palladium, chromium, seaborgium, titanium, antimony, bismuth, thallium, Examples include germanium, cadmium, silicon, tungsten, and molybdenum. As for these metals, only 1 type may be used and 2 or more types may be used together. In the conductive layer X, when a plurality of metals are included, the plurality of metals may be alloyed.

The method for forming the conductive layer X on the surface of the substrate particles is not particularly limited. As a method for forming the conductive layer, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a paste containing metal powder or metal powder and a binder is used for base particles or other conductive layers. For example, a method of coating the surface. Since the formation of the conductive layer is simple, a method by electroless plating is preferred. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 100 μm or less, more preferably 20 μm or less, still more preferably 5 μm or less, and particularly preferably 3 μm or less. When the particle diameter of the conductive particles is not less than the lower limit and not more than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes can be sufficiently increased, In addition, it is possible to make it difficult to form aggregated conductive particles when forming the conductive layer. Moreover, the space | interval between the electrodes connected through the electroconductive particle does not become large too much, and it can make it difficult to peel the electroconductive layer from the surface of base material particle.

The particle diameter of the conductive particles indicates the diameter when the conductive particles are true spherical, and indicates the maximum diameter when the conductive particles are not true spherical.

The conductive layer X may be formed of a single layer or a plurality of layers. That is, the conductive layer X may have a laminated structure of two or more layers. In addition to the conductive layer X, the conductive particles may include a gold layer, a nickel layer, a palladium layer, a copper layer, a silver layer, or an alloy layer containing tin and silver as the outermost layer.

As a method for controlling each content and average content of nickel, tin and indium in each region of the conductive layer X, for example, when forming the conductive layer X by electroless nickel plating, the pH of the nickel plating solution And a method for adjusting the tin and indium concentrations in the nickel plating solution and a method for adjusting the nickel concentration in the nickel plating solution.

In the method of forming by electroless plating, generally, a catalytic step and an electroless plating step are performed. Hereinafter, an example of a method for forming a plating layer containing nickel on the surface of resin particles by electroless plating will be described.

In the catalyzing step, a catalyst serving as a starting point for forming a plating layer by electroless plating is formed on the surface of the resin particles.

As a method of forming the catalyst on the surface of the resin particles, for example, after adding the resin particles to a solution containing palladium chloride and tin chloride, the surface of the resin particles is activated with an acid solution or an alkali solution, A method of depositing palladium on the surface of the resin particles, and after adding the resin particles to a solution containing palladium sulfate, the surface of the resin particles is activated by a solution containing a reducing agent, and palladium is added to the surface of the resin particles. The method of making it precipitate etc. is mentioned.

In the electroless plating step, a nickel plating bath containing at least one of a nickel-containing compound, the reducing agent, a complexing agent, a tin-containing compound, and an indium-containing compound is preferably used. By immersing the resin particles in the nickel plating bath, nickel can be deposited on the surface of the resin particles on which the catalyst is formed, and the conductive layer X can be formed. Further, when nickel is deposited, at least one of tin and indium is co-deposited, whereby an alloy plating layer containing nickel and at least one of tin and indium can be formed.

Examples of the nickel-containing compound include nickel sulfate and nickel chloride. The nickel-containing compound is preferably a nickel salt.

Examples of the reducing agent include sodium hypophosphite, dimethylamine borane, sodium borohydride, potassium borohydride, hydrazine monohydrate, hydrazinium sulfate, and titanium (III) chloride.

Examples of the tin-containing compound include sodium stannate trihydrate, potassium stannate trihydrate, tin (II) sulfate, tin (IV) chloride pentahydrate, and tin (II) chloride dihydrate. Can be mentioned.

Examples of the indium-containing compound include indium (III) acetate, indium (III) sulfate trihydrate, indium chloride (III), indium (III) hydroxide, and indium (III) nitrate.

The complexing agents include monocarboxylic acid complexing agents such as sodium acetate and sodium propionate; dicarboxylic acid complexing agents such as disodium malonate; tricarboxylic acid complexing agents such as disodium succinate; lactic acid, DL-malic acid, Rochelle salt, hydroxy acid complexing agents such as sodium citrate and sodium gluconate; amino acid complexing agents such as glycine and EDTA; amine complexing agents such as ethylenediamine; organic acids such as maleic acid Complexing agents; and salts thereof. It is preferable to use at least one complexing agent selected from the group consisting of the complexing agents mentioned here.

(Core material)
The conductive particles preferably have protrusions on the conductive surface. The conductive layer preferably has a protrusion on the outer surface. A plurality of the protrusions are preferable. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Furthermore, an oxide film is often formed on the surface of the conductive layer of the conductive particles. By using the conductive particles having the protrusions, the oxide film is effectively eliminated by the protrusions by placing the conductive particles between the electrodes and then pressing them. For this reason, an electrode and electroconductive particle can be contacted still more reliably and the connection resistance between electrodes can be made low. Furthermore, when the conductive particles have an insulating material on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the conductive particles and the electrodes are separated by protrusions of the conductive particles. Insulating substances or binder resins in between can be effectively eliminated. For this reason, the conduction | electrical_connection reliability between electrodes can be improved.

Further, when the conductive particles have protrusions on the outer surface of the conductive layer, the area where the conductive particles are in contact with each other can be reduced. Therefore, aggregation of the plurality of conductive particles can be suppressed. Therefore, electrical connection between the electrodes that should not be connected can be prevented, and insulation reliability can be further improved.

It is easy for the conductive layer to have a plurality of protrusions on the outer surface by embedding the core substance in the conductive layer. However, in order to form protrusions on the outer surfaces of the conductive particles and the conductive layer, it is not always necessary to use a core substance, and it is preferable not to use a core substance. The conductive particles are formed on the conductive layer. It is preferred not to have a core material for raising the outer surface. However, the conductive particles may have a core substance that bulges the outer surface of the conductive layer. When the core material is used, the core material is preferably disposed inside or inside the conductive layer.

As a method for forming the protrusions, a method of forming a conductive layer by electroless plating after attaching a core substance to the surface of the base particle, and a method of forming a conductive layer by electroless plating on the surface of the base particle And a method of forming a conductive layer by electroless plating, and a method of adding a core material in the middle of forming the conductive layer by electroless plating on the surface of the substrate particles.

As a method of arranging the core substance on the surface of the base particle, for example, the core substance is added to the dispersion of the base particle, and the core substance is applied to the surface of the base particle, for example, van der Waals force. And a method in which a core substance is added to a container containing base particles, and a core substance is attached to the surface of the base particles by mechanical action such as rotation of the container. . Since it is easy to control the amount of the core material to be adhered, a method of accumulating the core material on the surface of the base particle in the dispersion and attaching it is preferable.

The material of the core substance includes a conductive substance and a non-conductive substance. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive substance include silica, alumina, barium titanate, zirconia, and the like. In order to effectively eliminate the oxide film, the core material is preferably hard. A metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles. As the metal that is the material of the core substance, the metals mentioned as the material of the conductive layer can be used as appropriate.

Specific examples of the core material include barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6-7), titanium oxide (Mohs hardness 7), zirconia. (Mohs hardness 8-9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10), and the like. The inorganic particles are preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, titanium oxide, zirconia. Alumina, tungsten carbide or diamond is more preferable, and zirconia, alumina, tungsten carbide or diamond is particularly preferable. The Mohs hardness of the core material is preferably 5 or more, more preferably 6 or more, still more preferably 7 or more, and particularly preferably 7.5 or more.

Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead. Examples include alloys composed of two or more metals such as alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and tungsten carbide. Nickel, copper, silver or gold is preferred. The metal for forming the core substance may be the same as or different from the metal for forming the conductive part. The metal for forming the core substance preferably includes a metal for forming the conductive part. The metal for forming the core substance preferably contains nickel. The metal for forming the core substance preferably contains nickel.

The shape of the core substance is not particularly limited. The shape of the core substance is preferably a lump. Examples of the core substance include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an irregular lump.

The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes can be effectively reduced.

The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

The number of the protrusions per one of the conductive particles is preferably 3 or more, more preferably 5 or more. The upper limit of the number of protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle diameter of the conductive particles.

The average height of the plurality of protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average height of the protrusions is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes can be effectively lowered.

(Insulating material)
The conductive particles preferably include an insulating substance disposed on the surface of the conductive layer. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. In addition, the insulating substance between the conductive layer of an electroconductive particle and an electrode can be easily excluded by pressurizing electroconductive particle with two electrodes in the case of the connection between electrodes. In the case where the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating substance between the conductive layer of the conductive particles and the electrode can be more easily eliminated.

The insulating substance is preferably an insulating particle because the insulating substance can be more easily removed during crimping between the electrodes.

Specific examples of the insulating resin that is the material of the insulating material include polyolefin compounds, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, heat Examples thereof include curable resins and water-soluble resins.

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

As a method of disposing an insulating substance on the outer surface of the conductive layer, there are a chemical method, a physical or mechanical method, and the like. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. A method in which the insulating substance is arranged on the surface of the conductive layer through a chemical bond is preferable because the insulating substance is difficult to be detached.

The outer surface of the conductive layer and the surface of the insulating particles may each be coated with a compound having a reactive functional group. The outer surface of the conductive layer and the surface of the insulating particles may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing a carboxyl group into the outer surface of the conductive layer, the carboxyl group may be chemically bonded to a functional group on the surface of the insulating particle through a polymer electrolyte such as polyethyleneimine.

The average diameter (average particle diameter) of the insulating material can be appropriately selected depending on the particle diameter and use of the conductive particles. The average diameter (average particle diameter) of the insulating substance is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.5 μm or less. When the average diameter of the insulating material is equal to or more than the lower limit, the conductive layers of the plurality of conductive particles can be made difficult to contact each other when the conductive particles are dispersed in the binder resin. When the average diameter of the insulating particles is not more than the above upper limit, it is not necessary to increase the pressure excessively in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes. It does not have to be heated to a high temperature.

The “average diameter (average particle diameter)” of the insulating material indicates a number average diameter (number average particle diameter). The average diameter of the insulating material is determined using a particle size distribution measuring device or the like.

(Conductive material)
The conductive material according to the present invention includes the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive particles and the conductive material are each preferably used for electrical connection between electrodes. The conductive material is preferably a circuit connecting material.

The binder resin is not particularly limited. As the binder resin, a known insulating resin is used.

Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, and polyamide resin. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated products of styrene block copolymers. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

The conductive material and the binder resin preferably contain a thermoplastic component or a thermosetting component. The conductive material and the binder resin may contain a thermoplastic component or may contain a thermosetting component. The conductive material and the binder resin preferably contain a thermosetting component. The thermosetting component preferably contains a curable compound that can be cured by heating and a thermosetting agent. The thermosetting agent is preferably a thermal cation curing initiator. The curable compound curable by heating and the thermosetting agent are used in an appropriate blending ratio so that the binder resin is cured. When the binder resin contains a thermal cation curing initiator, an acid is easily contained in the cured product. However, the connection resistance between the electrodes can be kept low by using the conductive particles according to the present invention.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a light stabilizer. Various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

The conductive material can be used as a conductive paste and a conductive film. When the conductive material is a conductive film, a film that does not include conductive particles may be laminated on a conductive film that includes conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

The content of the binder resin in 100% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably It is 99.99 weight% or less, More preferably, it is 99.9 weight% or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further increased. Can do.

In 100% by weight of the conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 60% by weight. Hereinafter, it is more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% 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 conduction reliability between the electrodes can be further enhanced.

(Connection structure)
A connection structure can be obtained by connecting a connection object member using the conductive particles or using the conductive material containing the conductive particles and a binder resin.

The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the material of the connection portion is the present invention. It is preferable that the connection structure is a conductive particle according to the present invention, or a conductive structure according to the present invention including the conductive particle and a binder resin. It is preferable that the connecting portion is formed of the conductive particles according to the present invention, or is formed of the conductive material according to the present invention including the conductive particles and a binder resin. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles.

FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

The connection structure 51 shown in FIG. 5 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 connecting the first and second

connection target members

52 and 53. Prepare. The connection portion 54 is formed by curing a conductive material including the conductive particles 1. In FIG. 5, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1,

conductive particles

11, 21, etc. may be used.

The first connection target member 52 has a plurality of first electrodes 52a on the surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on the surface (lower surface). The first electrode 52 a and the second electrode 53 a are electrically connected by one or a plurality of conductive particles 1. Therefore, the first and second

connection target members

52 and 53 are electrically connected by the conductive particles 1.

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a multilayer body, and then the multilayer body is heated. And a method of applying pressure. The pressurizing pressure is about 9.8 × 10 ⁴ to 4.9 × 10 ⁶ Pa. The heating temperature is about 120 to 220 ° C.

Specific examples of the connection target member include electronic components such as a semiconductor chip, a capacitor, and a diode, and circuit boards such as a printed board, a flexible printed board, a glass epoxy board, and a glass board. The connection target member is preferably an electronic component. The conductive particles are preferably used for electrical connection of electrodes in an electronic component.

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

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. The present invention is not limited only to the following examples.

Example 1
Divinylbenzene copolymer resin particles having a particle diameter of 3.0 μm (base particle A, “Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) were prepared. After dispersing 10 parts by weight of the above base particle A in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the base particle A was taken out by filtering the solution. . Subsequently, the base particle A was added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the base particle A. The substrate particles A whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. Next, 2 g of Ni particle slurry (average particle size 150 nm) was added to the dispersion over 3 minutes to obtain a suspension (0) containing base particles to which the core material was adhered.

In addition, a nickel plating solution (1) (pH 8.5) containing nickel sulfate 0.14 mol / L, dimethylamine borane 0.46 mol / L and sodium citrate 0.2 mol / L is prepared as the nickel plating solution (1). did.

While stirring the obtained suspension (0) at 60 ° C., the nickel plating solution (1) is gradually added dropwise to the suspension to perform electroless nickel-boron alloy plating. )

As nickel plating solution (2), nickel sulfate 0.14 mol / L, sodium stannate trihydrate 0.03 mol / L, titanium (III) chloride 0.60 mol / L, and sodium gluconate 0.15 mol / L A nickel plating solution (2) (pH 8.0) was prepared.

The liquid temperature of the suspension (1) was set to 70 ° C., and the nickel plating solution (2) was gradually added dropwise to the suspension (1) to perform electroless nickel-aces alloy plating. 2) was obtained.

Thereafter, by filtering the suspension (2), the particles are taken out, washed with water, and dried, whereby a conductive layer (thickness 0.1 μm) containing nickel is disposed on the surface of the base particle A, and the surface Conductive particles having a conductive layer were obtained.

(Example 2)
Conductive particles were obtained in the same manner as in Example 1, except that 0.03 mol / L of sodium stannate trihydrate in the nickel plating solution (2) was changed to 0.04 mol / L of indium acetate (III). It was.

(Example 3)
Conductive particles were obtained in the same manner as in Example 1 except that the Ni particle slurry was changed to alumina particle slurry.

Example 4
Conductive particles were obtained in the same manner as in Example 1, except that the Ni particles slurry was not used for forming the protrusions, and the protrusions were formed by adjusting the amount of precipitation to partially change during the formation of the conductive portions. .

(Example 5)
Conductive particles were obtained in the same manner as in Example 1, except that 0.60 mol / L of titanium (III) chloride in the nickel plating solution (2) was changed to 0.46 mol / L of dimethylamine borane.

(Example 6)
Dimethylamine borane 0.46 mol / L in nickel plating solution (1) was changed to 1.40 mol / L sodium hypophosphite, and titanium (III) chloride in nickel plating solution (2) 0.60 mol / L Was changed to sodium hypophosphite 1.40 mol / L in the same manner as in Example 1 to obtain conductive particles.

(Example 7)
Conductive particles were obtained in the same manner as in Example 1 except that 0.46 mol / L of dimethylamine borane in the nickel plating solution (1) was changed to 0.60 mol / L of titanium (III) chloride.

(Example 8)
Conductive particles were obtained in the same manner as in Example 1 except that sodium stannate trihydrate 0.02 mol / L and sodium gluconate 0.10 mol / L were added to the nickel plating solution (1). .

Example 9
Conductive particles were obtained in the same manner as in Example 1 except that sodium stannate trihydrate 0.04 mol / L and sodium gluconate 0.20 mol / L were added to the nickel plating solution (1). .

(Example 10)
The addition amount of sodium stannate trihydrate in the nickel plating solution (2) was changed from 0.03 mol / L to 0.05 mol / L, and the addition amount of sodium gluconate in the nickel plating solution (2) was 0. Conductive particles were obtained in the same manner as in Example 1 except that the amount was changed from 15 mol / L to 0.25 mol / L.

(Example 11)
Addition of sodium stannate trihydrate 0.04 mol / L and sodium gluconate 0.20 mol / L to nickel plating solution (1), addition of sodium stannate trihydrate of nickel plating solution (2) The amount was changed from 0.03 mol / L to 0.05 mol / L, and the addition amount of sodium gluconate in the nickel plating solution (2) was changed from 0.15 mol / L to 0.25 mol / L. In the same manner as in Example 1, conductive particles were obtained.

Example 12
The amount of sodium stannate trihydrate added to the nickel plating solution (2) was changed from 0.03 mol / L to 0.02 mol / L, and indium (III) acetate was added to the nickel plating solution (2). Conductive particles were obtained in the same manner as in Example 1 except that 02 mol / L was added.

(Example 13)
The composition of the nickel plating solution (1) (pH 8.5) was changed to nickel sulfate 0.18 mol / L, dimethylamine borane 0.66 mol / L and sodium citrate 0.25 mol / L, nickel plating solution (2 ) (PH 8.0), nickel sulfate 0.18 mol / L, sodium stannate trihydrate 0.04 mol / L, titanium (III) chloride 0.75 mol / L, and sodium gluconate 0.19 mol / L Conductive particles were obtained in the same manner as in Example 1 except that the thickness was changed to L and the thickness of the conductive layer was changed from 0.1 μm to 0.15 μm.

(Example 14)
The composition of the nickel plating solution (1) (pH 8.5) was changed to nickel sulfate 0.07 mol / L, dimethylamine borane 0.23 mol / L, and sodium citrate 0.10 mol / L, and the nickel plating solution ( 2) The composition of pH 8.0 is nickel sulfate 0.07 mol / L, sodium stannate trihydrate 0.02 mol / L, titanium (III) chloride 0.3 mol / L, and sodium gluconate 0.10 mol / L Conductive particles were obtained in the same manner as in Example 1 except that it was changed to L and the thickness of the conductive layer was changed from 0.1 μm to 0.06 μm.

(Example 15)
A substrate particle B having a particle size different from that of the substrate particle A and having a particle size of 2.2 μm was prepared. Except having changed the said base material particle A into the said base material particle B, it carried out similarly to Example 1, and obtained electroconductive particle.

(Example 16)
A base material particle C having a particle diameter of 10.0 μm, which was different from the base material particle A, was prepared. Except having changed the said base material particle A into the said base material particle C, it carried out similarly to Example 1, and obtained electroconductive particle.

(Example 17)
In a 500 mL reaction vessel equipped with a stirrer and a thermometer, 300 g of a 0.13% by weight aqueous ammonia solution was placed. Next, 4.1 g of methyltrimethoxysilane, 19.2 g of vinyltrimethoxysilane, and 0.7 g of silicone alkoxy oligomer (“X-41-1053” manufactured by Shin-Etsu Chemical Co., Ltd.) in an aqueous ammonia solution in the reaction vessel. The mixture with was added slowly. After the hydrolysis and condensation reaction proceeded with stirring, 2.4 mL of a 25 wt% aqueous ammonia solution was added, and then the particles were isolated from the aqueous ammonia solution, and the resulting particles were subjected to an oxygen partial pressure of 10 ⁻¹⁷ atm. And calcination at 350 ° C. for 2 hours to obtain organic-inorganic hybrid particles (base particle D) having a particle size of 3.0 μm. Except having changed the said base material particle A into the said base material particle D, it carried out similarly to Example 3, and obtained electroconductive particle.

(Example 18)
Conductive particles were obtained in the same manner as in Example 1 except that the surface area of the portion with protrusions was changed from 70% to 25% out of 100% of the total surface area of the outer surface of the conductive part.

(Example 19)
To a 1000 mL separable flask equipped with a four-necked separable cover, stirring blade, three-way cock, condenser and temperature probe, 100 mmol of methyl methacrylate and N, N, N-trimethyl-N-2-methacryloyloxyethyl A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchanged water so that the solid content was 5% by weight. Then, it stirred at 200 rpm and superposed | polymerized for 24 hours at 70 degreeC by nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm, and a CV value of 10%. The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles. 10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion exchange water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto. When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.5 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

(Comparative Example 1)
The addition amount of sodium stannate trihydrate in the nickel plating solution (2) was changed from 0.03 mol / L to 0.10 mol / L, and the addition amount of sodium gluconate in the nickel plating solution (2) was 0. Conductive particles were obtained in the same manner as in Example 1 except that the amount was changed from .15 mol / L to 0.35 mol / L.

(Comparative Example 2)
Conductive particles were obtained in the same manner as in Comparative Example 1 except that sodium stannate trihydrate 0.04 mol / L and sodium gluconate 0.20 mol / L were added to the nickel plating solution (1). It was.

(Evaluation)
(1) Average content of nickel, tin and indium in the entire conductive layer containing nickel Add 5 g of conductive particles to a mixed solution of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid to completely dissolve the conductive layer, A solution was obtained. Using the obtained solution, the contents of nickel, tin and indium were analyzed by a high frequency inductively coupled plasma ion source mass spectrometer (“ICP-MS” manufactured by Hitachi, Ltd.). In addition, content other than nickel, tin, and indium was phosphorus or boron.

(2) Average content of nickel, tin and indium in the thickness direction of the conductive layer containing nickel The distribution of the content of nickel, tin and indium in the thickness direction of the conductive layer containing nickel was measured.

A thin film slice of the obtained conductive particles was prepared using a focused ion beam. Content of nickel, tin, and indium in the thickness direction of the conductive layer containing nickel by using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by JEOL Ltd.) with an energy dispersive X-ray analyzer (EDS) Was measured. From this result, the above-mentioned region (R1) (region of 50% thickness on the inner surface side) from the inner surface to the outer side of the conductive layer containing nickel, the inner side from the outer surface of the conductive layer containing nickel The region (R2) having a thickness up to ½ toward the surface (region having a thickness of 50% on the outer surface side), and the region (R3) having a thickness of ¼ from the outer surface of the conductive layer containing nickel toward the inside (Region having a thickness of 25% on the outer surface side) and the region (R4) from the position of the thickness 1/4 to the position of the thickness 1/2 from the outer surface of the conductive layer containing nickel to the inner side (outer surface The average content of nickel, tin and indium in the region between the position of 25% thickness and the position of 50% thickness from the side) was determined. In addition, content other than nickel, tin, and indium was phosphorus or boron. Moreover, the distribution result of the content of nickel, tin, and indium in the thickness direction of the conductive layer containing nickel was obtained by the above measurement. From this result, the maximum value of the total content of tin and indium in the region (R3) was obtained.

(3) Melting point of conductive layer of conductive particles The melting point of the conductive layer of the obtained conductive particles was measured using a differential scanning calorimeter (“DSC-6300” manufactured by Yamato Scientific Co., Ltd.). As a result, the melting point of the conductive layer in the example was 300 ° C. or higher.

(4) 10% K Value of Conductive Particles The 10% K value of the obtained conductive particles was measured using a micro compression tester (“Fischer Scope H-100” manufactured by Fischer).

(5) Volume resistivity of conductive particles The volume resistivity of the obtained conductive particles was measured using a “powder resistivity measurement system” manufactured by Mitsubishi Chemical Corporation.

(6) Connection resistance A (initial)
Fabrication of connection structure:
20 parts by weight of an epoxy compound that is a thermosetting compound (“EP-3300P” manufactured by Nagase ChemteX), 15 parts by weight of an epoxy compound that is a thermosetting compound (“EPICLON HP-4032D” manufactured by DIC), 5 parts by weight of a thermal cation generator (Sun Shin “SI-60” manufactured by Sanshin Chemical Co., Ltd.) as a curing agent and 20 parts by weight of silica (average particle size of 0.25 μm) as a filler were further obtained. After the conductive particles were added so that the content in the blend of 100% by weight was 10% by weight, the anisotropic conductive paste was obtained by stirring at 2000 rpm for 5 minutes using a planetary stirrer.

A glass substrate having an Al—Ti 4% electrode pattern (Al—Ti 4% electrode thickness 1 μm) with an L / S of 20 μm / 20 μm on the upper surface was prepared. A semiconductor chip having a gold electrode pattern (gold electrode thickness 20 μm) with L / S of 20 μm / 20 μm on the lower surface was prepared.

An anisotropic conductive material layer was formed on the upper surface of the glass substrate by coating the anisotropic conductive paste immediately after fabrication to a thickness of 20 μm. Next, the semiconductor chip was stacked on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer becomes 170 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 2.5 MPa is applied to apply the anisotropic conductive material. The material layer was cured at 170 ° C. to obtain a connection structure.

Connection resistance measurement:
The connection resistance A between the opposing electrodes of the obtained connection structure was measured by the 4-terminal method. Further, the connection resistance A was determined according to the following criteria.

[Evaluation criteria for connection resistance A]
○○○: Connection resistance A is 2.0Ω or less ○○: Connection resistance A exceeds 2.0Ω, 3.0Ω or less ○: Connection resistance A exceeds 3.0Ω, 5.0Ω or less Δ: Connection resistance A Exceeds 5.0Ω and 10Ω or less ×: Connection resistance A exceeds 10Ω

(7) Connection resistance B (after the influence of acid)
The obtained conductive particles were immersed in a 5% aqueous sulfuric acid solution for 30 minutes. Thereafter, the particles were taken out by filtration, washed with water, substituted with ethanol and allowed to stand for 10 minutes to dry the particles, thereby obtaining conductive particles exposed to acid. Using the obtained conductive particles, a connection structure was prepared in the same manner as in the above (6), and the connection resistance B was measured in the same manner as the connection resistance A. Further, the connection resistance B was determined based on the following criteria.

[Evaluation criteria for connection resistance B]
○○○: Connection resistance B is 1 time or more and less than 1.5 times connection resistance A ○○: Connection resistance B is 1.5 times or more and less than 2 times connection resistance A ○: Connection resistance B is connection resistance A 2 times or more and less than 5 times Δ: Connection resistance B is 5 times or more of connection resistance A and less than 10 times ×: Connection resistance B is 10 times or more of connection resistance A

(8) Connection resistance C (after the influence of alkali)
The obtained conductive particles were immersed in a 5% aqueous sodium hydroxide solution for 30 minutes. Thereafter, the particles were taken out by filtration, washed with water, substituted with ethanol and allowed to stand for 10 minutes to dry the particles, thereby obtaining conductive particles exposed to alkali. Using the obtained conductive particles, a connection structure was prepared in the same manner as in the above (6), and the connection resistance C was measured in the same manner as the connection resistance A. Further, the connection resistance C was determined according to the following criteria.

[Evaluation criteria for connection resistance C]
○○○: Connection resistance C is 1 or more times and less than 1.5 times connection resistance A ○○: Connection resistance C is 1.5 times or more and less than 2 times connection resistance A ○: Connection resistance C is connection resistance A 2 times or more and less than 5 times Δ: Connection resistance C is 5 times or more than connection resistance A and less than 10 times ×: Connection resistance C is 10 times or more of connection resistance A

(9) Aggregation state 10 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of acrylic rubber (weight average molecular weight of about 800,000), 200 parts by weight of methyl ethyl ketone, and microcapsule type curing 50 parts by weight of the agent (“HX3941HP” manufactured by Asahi Kasei Chemicals Co., Ltd.) and 2 parts by weight of the silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone Co., Ltd.) are mixed to give a conductive particle content of 3% by weight. Thus, an anisotropic conductive material was obtained. In addition, the conductive particle used the particle | grains of three conditions used by connection resistance A, connection resistance B, and connection resistance C, and produced three types of anisotropic conductive materials.

The three types of anisotropic conductive materials obtained were stored at 25 ° C. for 72 hours. After storage, it was evaluated whether or not the conductive particles aggregated in the anisotropic conductive material were settled. The aggregation state was determined according to the following criteria.

[Judgment criteria for aggregation state]
○: Aggregated conductive particles are not precipitated in all three types of anisotropic conductive materials. Δ: Aggregated conductive particles are precipitated only with one type of anisotropic conductive materials. Agglomerated conductive particles are settled with more than one kind of anisotropic conductive material

The results are shown in Tables 1 to 3 below.

DESCRIPTION OF SYMBOLS 1 ... Conductive particle 2 ... Base particle 3 ... Conductive layer containing nickel 11 ... Conductive particle 11a ... Protrusion 12 ... Conductive layer containing nickel 12a ... Protrusion 13 ... Core substance 14 ... Insulating substance 21 ... Conductive particle 21a ... Protrusions 22 ... Nickel-containing conductive layer 22a ... Protrusions 22A ... First conductive layer 22Aa ... Protrusions 22B ... Second conductive layers 22Ba ... Protrusions 51 ... Connection structure 52 ... First connection object member 52a ... First Electrode 53 ... second connection target member 53a ... second electrode 54 ... connection portion

Claims

Comprising base material particles and a conductive layer disposed on the surface of the base material particles and containing nickel;
The conductive layer containing nickel is an alloy layer containing nickel and at least one of tin and indium;
Conductive particles in which the total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the outer surface to the thickness ½ toward the inside from the outer surface of the conductive layer containing nickel.
The total average content of tin and indium in the region from the outer surface of the conductive layer containing nickel to the thickness ¼ toward the inner side has a thickness of 1 from the outer surface of the conductive layer containing nickel toward the inner side. 2. The conductive particle according to claim 1, wherein the conductive particle is larger than an average content of tin and indium in a region between a position of / 4 and a position of a thickness of ½.
The maximum value of the total content of tin and indium is 50% by weight or less in 100% by weight of the region from the outer surface to the thickness ¼ toward the inside from the outer surface of the conductive layer containing nickel. Or the electroconductive particle of 2.
The conductive particle according to any one of claims 1 to 3, wherein the nickel-containing conductive layer has a protrusion on an outer surface.
The conductive particles according to any one of claims 1 to 4, having a volume resistivity of 0.003 Ω · cm or less.
The total average content of tin and indium is less than 5% by weight in 100% by weight of the region from the inner surface to the thickness ½ toward the outside from the inner surface of the conductive layer containing nickel. Electroconductive particle of any one of these.
The conductive particle according to any one of claims 1 to 6, further comprising an insulating material disposed on an outer surface of the conductive layer containing nickel.
A conductive material comprising the conductive particles according to any one of claims 1 to 7 and a binder resin.
A first connection target member;
A second connection target member;
A connecting portion connecting the first connection target member and the second connection target member;
A connection structure, wherein the material of the connection part is the conductive particles according to any one of claims 1 to 7, or a conductive material containing the conductive particles and a binder resin.