KR102685922B1 - Conductive particles, conductive materials and connection structures - Google Patents

Abstract

Provided are conductive particles that can suppress corrosion of a conductive layer containing nickel even in the presence of either an acid or an alkali. The conductive particle according to the present invention includes a substrate particle and a conductive layer containing nickel disposed on the surface of the substrate particle, and the conductive layer containing nickel contains at least one of nickel, tin, and indium. It is an alloy layer, and the average total content of tin and indium in 100% by weight of the area from the outer surface of the conductive layer containing nickel to 1/2 of the thickness toward the inside is less than 5% by weight.

Description

Conductive particles, conductive materials and connection structures

This invention relates to electroconductive particles in which a conductive layer containing nickel is disposed on the surface of a substrate particle. Furthermore, the present invention relates to an electrically conductive material and a bonded structure using the above-mentioned electrically conductive particles.

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

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

When, for example, the electrode of a semiconductor chip and the electrode of a glass substrate are electrically connected by the anisotropic conductive material, the anisotropic conductive material containing conductive particles is disposed on the glass substrate. Then, semiconductor chips are stacked, heated and pressed. Thereby, the anisotropic electrically-conductive material is hardened, the electrodes are electrically connected via electroconductive particles, and a connected structure is obtained.

As an example of the electroconductive particle, the following patent document 1 discloses an electroconductive particle having a substrate particle and a conductive metal layer covering the surface of the substrate particle. Specific examples of the metal constituting the conductive metal layer include nickel and 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 alloys (Cu and Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Ag, Au, Bi, Al, Mn, Mg, P, B an alloy with at least one metal element selected from the group consisting of, preferably an alloy with Ag, Ni, Sn, or Zn); Silver, silver alloy (Ag, Fe, Co, Ni, Zn, Sn, In, Ga, Tl, Zr, W, Mo, Rh, Ru, Ir, Au, Bi, Al, Mn, Mg, P, B) alloy with at least one metal element selected from the group, preferably Ag-Ni, Ag-Sn, Ag-Zn); Tin, tin alloys (e.g. Sn-Ag, Sn-Cu, Sn-Cu-Ag, Sn-Zn, Sn-Sb, Sn-Bi-Ag, Sn-Bi-In, Sn-Au, Sn-Pb, etc. ) is exemplified.

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

The following patent document 3 discloses an electroconductive particle including a substrate particle and a conductive layer containing nickel disposed on the surface of the substrate particle. The conductive layer is an alloy layer containing nickel and tin. The average content of tin in the total 100% by weight of the conductive layer is 5% by weight or more and 50% by weight or less.

Japanese Patent Publication No. 2013-125649 Japanese Patent Publication No. 2008-41671 Japanese Patent Publication No. 2015-130328

When conventional conductive particles such as those described in Patent Documents 1 and 2 are exposed to the presence of acid, corrosion of the conductive layer containing nickel may occur. Additionally, when conventional conductive particles such as those described in Patent Documents 1 to 3 are exposed to the presence of alkali, corrosion of the conductive layer containing nickel may occur. Additionally, when a bonded structure is obtained by connecting electrodes using conventional conductive particles, the connection resistance between electrodes may increase when the bonded structure is exposed to the presence of an acid or alkali. Additionally, as 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 embrittled, resulting in compression during connection between electrodes. It becomes easy for the conductive layer to crack.

The purpose of the present invention is to provide conductive particles that can suppress corrosion of a conductive layer containing nickel even in the presence of either an acid or an alkali.

Furthermore, the present invention also aims to provide an electrically conductive material and a bonded structure using the above-described electrically conductive particles.

According to a broad aspect of the present invention, it is provided with substrate particles and a conductive layer that is disposed on the surface of the substrate particle and contains nickel, and the conductive layer containing nickel is at least one of nickel, tin, and indium. It is an alloy layer containing one type, and the average content of the total of tin and indium is less than 5% by weight in 100% by weight of the area from the outer surface of the conductive layer containing nickel to 1/2 the thickness inward. Conductive particles are provided.

In a specific aspect of the conductive particle according to the present invention, the average content of the total of tin and indium in the region up to 1/4 of the thickness from the outer surface of the conductive layer containing the nickel toward the inside is the content of the total of tin and indium containing the nickel. It is greater than the total average content of tin and indium in the area between the 1/4th thickness position and the 1/2th thickness position from the outer surface of the conductive layer toward the inside.

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

In a certain situation of the electroconductive particle which concerns on this invention, the said nickel-containing conductive layer has protrusions 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 the total of tin and indium in 100% by weight of the area from the inner surface to the outside of the nickel-containing conductive layer up to 1/2 of the thickness is 5 weight. It is less than %.

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

According to a broad aspect of the present invention, an electrically conductive material containing the above-mentioned electrically conductive particles and binder resin is provided.

According to a broad aspect of the present invention, there is provided a first connection target member, a second connection target member, and a connection portion connecting the first connection target member and the second connection target member, and the material of the connection portion is: A bonded structure is provided, which is the conductive particles described above or a conductive material containing the conductive particles and a binder resin.

The conductive particle according to the present invention is provided with a substrate particle and a conductive layer that is disposed on the surface of the substrate particle and contains nickel, and the conductive layer containing nickel is at least one of nickel, tin, and indium. It is an alloy layer containing one type, and the average total content of tin and indium is less than 5% by weight in 100% by weight of the area from the outer surface to the inside of the nickel-containing conductive layer up to 1/2 of the thickness. , corrosion of the conductive layer containing nickel can be suppressed even in the presence of either acid or alkali.

1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention.
Fig. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.
Figures 4 (a) and (b) are schematic diagrams for explaining each region in which the average total content of tin and indium is calculated in the conductive layer containing nickel.
Fig. 5 is a front cross-sectional view schematically showing a bonded 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 arrange|positioned on the surface of a substrate particle and this substrate particle, and is provided with the conductive layer which contains nickel.

In addition, in the conductive particles according to the present invention, the conductive layer containing nickel is an alloy layer containing nickel and at least one type of tin and indium. In the conductive particle according to the present invention, the total average content of tin and indium in 100% by weight of the area from the outer surface of the conductive layer containing nickel to 1/2 the thickness toward the inside is less than 5% by weight.

Conductive particles may be exposed to acid or alkali conditions due to acidic gas or alkaline gas in the atmosphere or acidic or alkaline components other than the conductive particles contained in the electrically conductive material.

By employing the above-described structure in the conductive particles according to the present invention, corrosion of the conductive layer containing nickel can be suppressed even in the presence of either acid or alkali. Even if the conductive particles are exposed to the presence of an acid or alkali, corrosion of the conductive layer containing nickel is unlikely to occur, so the performance as the conductive particles can be maintained high. In the present invention, corrosion of the conductive layer containing nickel can be suppressed even in the presence of an acid, and corrosion of the conductive layer containing nickel can also be suppressed in the presence of an alkali.

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

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

In addition, in the conductive particle according to the present invention, since the conductive layer containing nickel contains at least one kind of tin and indium, the strong magnetism of nickel can be suppressed, and the effect of suppressing agglomeration due to magnetism is obtained. . For this reason, a plurality of conductive particles can be efficiently disposed on the electrode. Therefore, when the electrodes are electrically connected, the connection reliability and conduction reliability between the electrodes can be further improved. Additionally, electrical connection between adjacent electrodes in the horizontal direction that should not be connected can be prevented, and insulation reliability can be further improved. In addition, in the conductive particles according to the present invention, the average content of the total of tin and indium in 100% by weight of the area from the outer surface of the conductive layer containing nickel to the inner side up to 1/2 of the thickness is less than 5% by weight, Since the conductive layer is unlikely to become embrittled and corrosion of the conductive layer in the presence of an acid or alkali is unlikely to occur, aggregation of conductive particles accompanying a corrosion reaction of the conductive layer can also be suppressed.

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

Additionally, when the total average content of tin and indium is 5% by weight or less among the total 100% by weight of the conductive layer containing nickel, the conductive layer tends to be difficult to embrittle. Therefore, when the total average content of tin and indium in the total 100% by weight of the conductive layer containing nickel is 5% by weight or less, corrosion of the conductive layer in the presence of acid or alkali becomes more difficult to occur. , the connection resistance after exposure to the presence of acid or alkali can be kept low more effectively. Additionally, when the total average content of tin and indium is 5% by weight or less out of the total 100% by weight of the conductive layer containing nickel, the resistivity of the conductive layer tends to be difficult to increase, and compression occurs when connecting electrodes. Since cracking of the conductive layer is less likely to occur, the connection resistance can be kept low more effectively.

From the viewpoint of further improving the adhesion between the substrate particles and the nickel-containing conductive layer and further improving the connection reliability between electrodes, the region (R1) extending from the inner surface of the nickel-containing conductive layer outward to 1/2 the thickness ), the average content of the total of tin and indium in 100% by weight is preferably 5% by weight or less, more preferably less than 5% by weight, further preferably 3% by weight or less, especially preferably 2% by weight or less. am. The region R1 is a region inside the broken line L1 of the conductive layer 3 containing nickel in Fig. 4(a).

The total average content of tin and indium in 100% by weight of the region R2 from the outer surface of the conductive layer containing nickel to 1/2 the thickness inward is less than 5% by weight. From the viewpoint of further improving the reliability of the connection between electrodes, out of the total 100% by weight of the nickel-containing conductive layer, 100% of the region (R2) from the outer surface of the nickel-containing conductive layer toward the inside to 1/2 the thickness. The average total content of tin and indium in weight% 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. 4(a).

The total average content of tin and indium in the region R1 is less than the total average content of tin and indium in the region R2, and the total average content of tin and indium in the region R2 is It may be equal to the total average content, or 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 particles and the conductive layer containing nickel, further improving the reliability of the connection between the electrodes, and further suppressing corrosion of the conductive particles due to acid or alkali, the region R1 The total average content of tin and indium 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 substrate particles and the nickel-containing conductive layer and further improving the connection reliability between electrodes, the area from the outer surface of the nickel-containing conductive layer toward the inside up to 1/4 of the thickness (R3 ), the average total 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. 4(b).

From the viewpoint of further improving the adhesion between the substrate particles and the nickel-containing conductive layer and further improving the connection reliability between electrodes, thickness 1 is applied at a position of 1/4 of the thickness toward the inside from the outer surface of the nickel-containing conductive layer. The average total content of tin and indium in 100% by weight of the region R4 up to the /2 position is preferably 10% by weight or less, more preferably 1% by weight or less. 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. 4(b).

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

In the region R3, there are cases where tin and indium are not uniformly distributed when the region R3 is viewed as a whole. The region R3 may have a portion where the total content of tin and indium is relatively high and a portion where the total content of tin and indium is relatively low. In the region R3, there may be a change in the total content of tin and indium. From the viewpoint of further improving the adhesion between the base particles and the conductive layer containing nickel, further improving the reliability of the connection between the electrodes, and further suppressing corrosion of the conductive particles due to acid or alkali, the region R3 The maximum value of the total content of tin and indium in 100% by weight 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 or less. . The maximum value of the total content of tin and indium represents the content at the position in the region R3 where the total content of tin and indium is the highest.

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, a thin film section of the obtained conductive particles is produced. Nickel, tin, and indium in the thickness direction of the conductive layer containing nickel were measured by energy dispersive X-ray spectrometry (EDS) using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by Nippon Electronics). By measuring the content, the content distribution results of nickel, tin, and indium in the thickness direction of the conductive layer containing nickel are 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, it is preferable that the melting point of the conductive layer containing nickel is 300°C or higher. A conductive layer with a melting point of 300°C or higher and containing nickel generally has a low average content of tin, so it is different from a solder layer generally called solder and different from a solder layer with 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 500°C or higher.

From the viewpoint of further lowering the connection resistance and further improving the reliability of the connection between electrodes, the compressive elastic modulus (10% K value) when the conductive particles are compressed by 10% is preferably 10 N/mm2 or more, more preferably. Preferably it is 50N/mm2 or more, preferably 4000N/mm2 or less, and more preferably 3000N/mm2 or less.

The compressive 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 the end surface of a smooth indenter of a cylinder (diameter 50 μm, made of diamond) under the conditions of applying a maximum test load of 90 mN for 30 seconds at 25°C. At this time, measure the load value (N) and compression displacement (mm). From the obtained measured values, the compressive elastic modulus can be obtained by the following equation. As the micro-compression tester, for example, “Fisher Scope H-100” manufactured by Fisher, etc. is used.

K value (N/㎟)=(3/2 ^1/2 )·F·S ^-3/2 ·R ^-1/2

F: Load value (N) when the conductive particles are compressed and deformed by 10%

S: Compression displacement (mm) when the conductive particles are compressed and deformed by 10%

R: Radius of conductive particle (mm)

The compressive elastic modulus universally and quantitatively indicates the hardness of conductive particles. By using the compressive elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

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

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

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

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

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

The conductive particles 1 are different from the conductive particles 11 and 21 described later and 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 protrusions on its outer surface. In this way, the conductive particles according to the present invention do not need to have protrusions on the conductive surface and may be spherical. Additionally, the conductive particles 1 are different from the conductive particles 11 and 21 described later and do not contain an insulating material. 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 electroconductive particle 1, the substrate particle 2 and the conductive layer 3 containing nickel are in contact with each other. A conductive layer not containing nickel may be disposed between the substrate particles and the conductive layer containing nickel, and a conductive layer not containing nickel may be disposed on the outer surface of the conductive layer containing nickel.

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

The electroconductive particle 11 shown in FIG. 2 has a substrate particle 2, a conductive layer 12 containing nickel, a plurality of core materials 13, and a plurality of insulating materials 14. The conductive layer 12 containing nickel is arranged so as to contact the substrate particle 2 on the surface of the substrate particle 2.

In the conductive particles 11, the conductive layer 12 containing nickel is a single-layer 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 in 100% by weight of the area from the outer surface to the inside of the nickel-containing conductive layer 12 up to 1/2 of the thickness is less than 5% by weight.

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 its outer surface. A plurality of core materials 13 are arranged on the surface of the substrate particles 2. A plurality of core materials 13 are embedded in a conductive layer 12 containing nickel. The core material 13 is disposed inside the protrusions 11a and 12a. The conductive layer 12 containing nickel covers a plurality of core materials 13. The outer surface of the conductive layer 12 containing nickel is raised by the plurality of core materials 13, and projections 11a and 12a are formed.

The conductive particles 11 have an insulating material 14 disposed on the outer surface of the conductive layer 12 containing nickel. At least a portion of the outer surface of the conductive layer 12 containing nickel is covered with the insulating material 14. The insulating material 14 is formed of an insulating material and is an insulating particle. In this way, the conductive particles according to the present invention may have an insulating substance disposed on the outer surface of the conductive layer. However, the conductive particles according to the present invention do not necessarily have to have an insulating substance.

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

The electroconductive particle 21 shown in FIG. 3 has a substrate particle 2, a 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 substrate particle 2 side, and a second conductive layer 22B on the opposite side to the substrate particle 2 side.

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

22A of 1st conductive layers are arrange|positioned on the surface of the substrate particle 2. The first conductive layer 22A is disposed between the substrate particles 2 and the second conductive layer 22B. The first conductive layer 22A is in contact with the substrate particle 2. The second conductive layer 22B is in contact with the first conductive layer 22A. Therefore, the first conductive layer 22A is disposed on the surface of the substrate 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 its outer surface. The first conductive layer 22A has a plurality of protrusions 22Aa on its outer surface. The second conductive layer 22B has a plurality of protrusions 22Ba on its 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, at least one of tin, and indium. Accordingly, the first conductive layer 22A and the second conductive layer 22B are each an alloy layer containing at least one of nickel, tin, and indium. The total average content of tin and indium in 100% by weight of the area from the outer surface to the inside of the nickel-containing conductive layer 22 up to 1/2 of the thickness is less than 5% by weight.

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. It is preferable that the said substrate particle is a substrate particle excluding a metal particle, and it is more preferable that it is a resin particle, an inorganic particle except a metal particle, or an organic-inorganic hybrid particle. The substrate 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 substrate particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. When connecting electrodes using the conductive particles, the conductive particles are placed between the electrodes and then compressed by pressing. If the substrate particles are resin particles or organic-inorganic hybrid particles, the conductive particles are likely to be deformed during compression, and the contact area between the conductive particles and the electrode increases. For this reason, the reliability of conduction between electrodes can be further improved.

As a resin for forming the resin particles, various organic substances are suitably used. Resins for forming the resin particles include, for example, 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, polyamidoimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer and divinylbenzene-based copolymer, etc. can be mentioned. Examples of the divinylbenzene-based copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer. Since the hardness of the resin particles can be easily controlled to an appropriate range, the resin for forming the resin particles is preferably a polymer obtained by polymerizing one or two or more types of polymerizable monomers having an ethylenically unsaturated group.

When the resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers.

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

Examples of the crosslinkable monomer include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Latex, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate polyfunctional (meth)acrylate compounds such as polyester, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; Triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ-(meth)acryloxypropyl trimethoxysilane, trimethoxysilyl styrene. and silane-containing monomers such as vinyltrimethoxysilane.

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

When the substrate particles are inorganic particles other than metal or organic-inorganic hybrid particles, examples of the inorganic materials for forming the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. It is preferable that the inorganic material is not a metal. The particles formed from the above silica are not particularly limited, but examples include particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, and then performing baking as necessary. You can. 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. It is preferred that the core is an organic core. It is preferred that the shell is an inorganic shell. From the viewpoint of effectively lowering the connection resistance between electrodes, it is preferable that the substrate particles are organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Materials for forming the organic core include resins for forming the above-mentioned resin particles.

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

The particle diameter 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, further preferably 50 μm or less, particularly preferably 20 μm or less. ㎛ or less, most preferably 10 ㎛ or less. If the particle size of the core is more than the above lower limit and less than the above upper limit, conductive particles more suitable for electrical connection between electrodes are obtained, and the substrate particles can be used suitably for the purpose of the conductive particles. For example, if the particle size of the core is equal to or greater than the lower limit and equal to or less than the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes becomes sufficiently large, and aggregation occurs when forming the conductive portion. This can make it difficult to form conductive particles. In addition, the gap between electrodes connected via the conductive particles does not become too large, and it is possible to make it difficult to peel the conductive portion from the surface of the substrate particle.

The particle diameter of the core means the diameter if the core is spherical, and the maximum diameter if the core has a shape other than a spherical shape. In addition, the particle size of the core means the average particle size of the core measured by an arbitrary particle size measuring device. For example, a particle size distribution measuring device using principles such as laser light scattering, changes in electrical resistance value, 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, and more preferably 3 μm or less. If the thickness of the shell is more than the lower limit and less than the upper limit, conductive particles more suitable for electrical connection between electrodes are obtained, and the substrate particles can be used suitably for the purpose of the conductive particles. The thickness of the shell is the average thickness per substrate particle. The thickness of the shell can be controlled by controlling the sol-gel method.

When the substrate particles are metal particles, examples of metals used as materials for the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, it is preferable that the said substrate particle is not a metal particle, and it is preferable that it is not a copper particle.

The particle diameter of the substrate particle 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 is 500 μm or less, more preferably 300 μm or less, further preferably 50 μm or less, even more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. If the particle diameter of the substrate particle is more than the above lower limit, the contact area between the conductive particles and the electrode increases, so the conduction reliability between the electrodes can be further improved, and the connection resistance between the electrodes connected via the conductive particles can be further improved. You can do it low. Additionally, when forming a conductive layer on the surface of a substrate particle by electroless plating, it can be difficult to form aggregated conductive particles. If the particle diameter of the said substrate particle is below the said upper limit, the electroconductive particle is easily compressed enough, the connection resistance between electrodes can be made further lower, and the space between electrodes can be made smaller.

When the substrate particle is spherical, the particle diameter of the substrate particle represents the diameter, and when the substrate particle is not spherical, it represents the maximum diameter.

It is especially preferable that the particle diameter of the said substrate particle is 2 micrometers or more and 5 micrometers or less. If the particle diameter of the substrate particle is within the range of 2 to 5 μm, the space between electrodes can be made smaller, and even if the thickness of the conductive layer is increased, small conductive particles can be obtained.

(Challenge floor)

The electroconductive particle which concerns on this invention is equipped with a conductive layer containing nickel arrange|positioned on the surface of a substrate particle and a substrate particle. The conductive layer containing nickel contains at least one of nickel, tin, and indium. The total average content of tin and indium in 100% by weight of the area from the outer surface to the inside of the nickel-containing conductive layer up to 1/2 of the thickness is less than 5% by weight. This nickel-containing conductive layer may be described as conductive layer X in the (Conductive Layer) column below. The conductive layer

From the viewpoint of effectively increasing conductivity, the larger the average content of nickel in the total 100% by weight of the conductive layer X, the better. Therefore, the average content of nickel in the total 100% by weight of the conductive layer It is % by weight or more, more preferably 85% by weight or more, particularly preferably 90% by weight or more, and most preferably 95% by weight or more. The average content of nickel in the total 100% by weight of the conductive layer If the average content of nickel is more than the above lower limit, the connection resistance between electrodes can be further lowered. Additionally, when the oxide film on the surface of the electrode or conductive layer is small, the connection resistance between electrodes tends to decrease as the average content of nickel increases.

The method of measuring each content of nickel, tin, and indium in the nickel-containing conductive layer (conductive layer It can be measured using a high-frequency inductively coupled plasma emission spectrometer (“ICP-AES” manufactured by Horiba Seisakusho Co., Ltd.), a fluorescence X-ray analyzer (“EDX-800HS” manufactured by Shimazu Seisakusho Co., Ltd.), etc.

The respective contents of nickel, tin, and indium in each region in the thickness direction of the conductive layer

The overall thickness of the conductive layer If the overall thickness of the conductive layer

It is particularly preferable that the overall thickness of the conductive layer X is 0.05 μm or more and 0.3 μm or less. Moreover, it is especially preferable that the particle diameter of the said substrate particle is 2 micrometers or more and 5 micrometers or less, and the overall thickness of the said conductive layer X is 0.05 micrometers or more and 0.3 micrometers or less. In this case, the conductive particles can be used more suitably for applications where a large current flows. Additionally, when electrically conductive particles are compressed to connect electrodes, damage to the electrodes can be further prevented.

The thickness of the conductive layer

The conductive layer X may contain a metal other than nickel, tin, and indium. Examples of metals other than nickel, tin, and indium in the conductive layer Examples include bismuth, thallium, germanium, cadmium, silicon, tungsten, and molybdenum. As for these metals, only one type may be used, and two or more types may be used together. In the conductive layer X, when a plurality of metals are contained, the plurality of metals may be alloyed.

The method of forming the conductive layer X on the surface of the substrate particle is not particularly limited. Methods for forming the conductive layer include, for example, a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and a method using metal powder or a paste containing metal powder and a binder as the base particle or other conductive layer. Examples include a method of coating the surface. Since the formation of the conductive layer is simple, the method using electroless plating is preferable. Examples of the physical vapor deposition method include vacuum 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, further preferably 5 μm or less, especially preferably is 3㎛ or less. If the particle diameter of the conductive particles is more than the above lower limit and less than the upper limit, when connecting electrodes using the above conductive particles, the contact area between the conductive particles and the electrode can be sufficiently increased, and further, they can cohere when forming the conductive layer. This can make it difficult to form conductive particles. In addition, the gap between electrodes connected via the conductive particles does not become too large, and it is possible to make it difficult to peel the conductive layer from the surface of the substrate particles.

The particle diameter of the electroconductive particle indicates the diameter when the electroconductive particle is spherical, and indicates the maximum diameter when the electroconductive particle is not spherical.

The conductive layer X may be formed of one layer or may be formed of multiple layers. That is, the conductive layer X may have a laminated structure of two or more layers. In addition to the conductive layer

As a method of controlling each content and each average content of nickel, tin, and indium in each region of the conductive layer a method of adjusting the concentration of tin and indium in the nickel plating solution, and a method of adjusting the nickel concentration of the nickel plating solution.

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

In the catalytic process, a catalyst that serves as a starting point for forming a plating layer by electroless plating is formed on the surface of the resin particle.

As a method of forming the catalyst on the surface of the resin particles, for example, the resin particles are added to a solution containing palladium chloride and tin chloride, and then the surface of the resin particles is activated with an acid solution or an alkaline solution. A method of precipitating palladium on the surface of, and a method of adding resin particles to a solution containing palladium sulfate and then activating the surface of the resin particles with a solution containing a reducing agent to precipitate palladium on the surface of the resin particles, etc. can be mentioned.

In the electroless plating process, a nickel plating bath containing a nickel-containing compound, the reducing agent, a complexing agent, and at least one of a tin-containing compound and an indium-containing compound is suitably used. By immersing the resin particles in a nickel plating bath, the catalyst can precipitate nickel on the surface of the resin particles formed on the surface, and the conductive layer X can be formed. Additionally, when precipitating nickel, an alloy plating layer containing nickel and at least one type of tin and indium can be formed by co-depositing at least one type of tin and indium.

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 compounds include sodium tartrate trihydrate, potassium tartrate trihydrate, tin(II) sulfate, tin(IV) chloride pentahydrate, and tin(II) chloride dihydrate.

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

The complexing agent includes monocarboxylic acid-based complexing agents such as sodium acetate and sodium propionate; Dicarboxylic acid-based complexing agents such as disodium malonate; Tricarboxylic acid-based complexing agents such as disodium succinate; Hydroxy acid-based complexing agents such as lactic acid, DL-malic acid, Rochelle's salt, sodium citrate, and sodium gluconate; Amino acid-based complexing agents such as glycine and EDTA; Amine-based complexing agents such as ethylenediamine; Organic acid-based complexing agents such as maleic acid; and salts thereof. It is preferable to use at least one complexing agent selected from the group consisting of the complexing agents exemplified here.

(core material)

It is preferable that the electrically conductive particles have protrusions on their electrically conductive surfaces. The conductive layer preferably has protrusions on its outer surface. It is preferable that the protrusions are plural. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Additionally, in many cases, an oxide film is formed on the surface of the conductive layer of the electrically conductive particles. By using the conductive particles having the above-described protrusions, the oxide film is effectively excluded by the protrusions by placing the conductive particles between electrodes and then pressing them. For this reason, the electrode and the conductive particles can be brought into contact more reliably, and the connection resistance between the electrodes can be lowered. Additionally, 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 protrusions of the conductive particles form an insulating material or binder resin between the conductive particles and the electrode. can be effectively ruled out. Because of this, the reliability of conduction between electrodes can be increased.

Additionally, if the conductive particles have protrusions on the outer surface of the conductive layer, the area where the conductive particles contact each other can be reduced. Therefore, aggregation of a plurality of the above-mentioned conductive particles can be suppressed. Therefore, electrical connection between electrodes that should not be connected can be prevented, and insulation reliability can be further improved.

Since the core material is embedded in the conductive layer, it is easy to make the conductive layer have a plurality of protrusions on the outer surface. However, in order to form protrusions on the outer surfaces of the conductive particles and the conductive layer, it is not necessarily necessary to use a core material, and it is preferable not to use a core material, and the conductive particles form the outer surface of the conductive layer. It is desirable not to have a core material for raising. However, the electrically conductive particles may have a core material that protrudes the outer surface of the electrically conductive layer. When the core material is used, the core material is preferably disposed inside or inside the conductive layer.

As a method of forming the protrusions, a method of forming a conductive layer by electroless plating after attaching a core material to the surface of a substrate particle, or a method of forming a conductive layer by electroless plating on the surface of a substrate particle, and then forming a conductive layer by electroless plating, A method of attaching a substance and further forming a conductive layer by electroless plating, and a method of adding a core material in the middle of forming a conductive layer on the surface of a substrate particle by electroless plating, etc.

As a method of disposing the core material on the surface of the substrate particles, for example, the core material is added to a dispersion of the substrate particles, and the core material is integrated and attached to the surface of the substrate particles by, for example, van der Waals forces. and a method of adding a core substance to a container containing base particles and attaching the core substance 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 attached, a method of attaching the core material by accumulating it on the surface of the substrate particles in the dispersion is preferable.

Materials of the core material include conductive materials and non-conductive materials. Examples of the conductive material include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive materials include silica, alumina, barium titanate, and zirconia. In order to effectively exclude the oxide film, the core material is preferably hard. Metal is preferable because conductivity can be increased and connection resistance can be effectively lowered. The core material is preferably a metal particle. As the metal that is the material of the core material, the metals mentioned as the material of the conductive layer can be appropriately used.

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

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

The shape of the core material is not particularly limited. The shape of the core material is preferably lumpy. Examples of the core material include a particulate mass, an agglomerated mass of a plurality of fine particles, and an irregular mass.

The average diameter (average particle diameter) of the core material is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, and more preferably 0.2 μm or less. If the average diameter of the core material is more than the lower limit and less than the upper limit, the connection resistance between electrodes can be effectively lowered.

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

The number of protrusions per one conductive particle 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, etc.

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, and more preferably 0.2 μm or less. If the average height of the protrusion is equal to or greater than the lower limit and equal to or lower than the upper limit, the connection resistance between electrodes can be effectively lowered.

(insulating material)

The conductive particles preferably include an insulating material disposed on the surface of the conductive layer. In this case, if the above-mentioned conductive particles are used for connection between electrodes, short circuits between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles come into contact, an insulating material exists between the plurality of electrodes, so short circuiting can be prevented not between the upper and lower electrodes but between electrodes adjacent to each other in the horizontal direction. Additionally, by pressing the conductive particles with two electrodes when connecting the electrodes, the insulating material between the conductive layers of the conductive particles and the electrodes can be easily removed. When the conductive particle has a plurality of protrusions on the outer surface of the conductive layer, the insulating material between the conductive layer of the conductive particle and the electrode can be removed more easily.

Since the insulating material can be more easily removed during compression between electrodes, it is preferable that the insulating material is insulating particles.

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 products of thermoplastic resins, thermosetting resins, and water-soluble resins. You can.

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 polymer and vinyl copolymer. Examples of the thermosetting resin include epoxy resin, phenol resin, and melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and methylcellulose. Water-soluble resin is preferable, and polyvinyl alcohol is more preferable.

Methods for disposing an insulating material on the outer surface of the conductive layer include chemical methods and physical or mechanical methods. Examples of the chemical method include interfacial polymerization, suspension polymerization in the presence of particles, and emulsion polymerization. Examples of the physical or mechanical methods include spray drying, hybridization, electrostatic attachment, spraying, dipping, and vacuum deposition. Since the insulating material is difficult to detach from, a method of disposing the insulating material on the surface of the conductive layer through a chemical bond is preferable.

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 particle do not have to be directly chemically bonded, but may be chemically bonded indirectly through a compound having a reactive functional group. After introducing a carboxyl group to the outer surface of the conductive layer, the carboxyl group may be chemically bonded to the surface functional group 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 size and purpose of the conductive particles. The average diameter (average particle diameter) of the insulating material is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, and more preferably 0.5 μm or less. If the average diameter of the insulating material is more than the above lower limit, when the conductive particles are dispersed in the binder resin, it can be difficult for the conductive layers of the plurality of conductive particles to contact each other. If the average diameter of the insulating particles is below the upper limit, the pressure does not need to be too high and the heating to a high temperature does not need to be made too high in order to exclude the insulating particles between the electrodes and the conductive particles when connecting the electrodes.

The “average diameter (average particle diameter)” of the insulating material represents the 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.

(Challenge Materials)

The electrically conductive material according to the present invention contains the above-mentioned electrically conductive particles and binder resin. It is preferable that the electrically conductive particles are dispersed in a binder resin so that they can be used as an electrically conductive material. It is preferable that the above-mentioned conductive material is an anisotropic conductive material. It is preferable that each of the electroconductive particles and the electroconductive material is used for electrical connection between electrodes. It is preferable that the above-mentioned conductive material is a material for circuit connection.

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

Examples of the binder resin include vinyl resin, thermoplastic resin, curable resin, thermoplastic block copolymer, and elastomer. Only one type of the binder resin may be used, and two 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 epoxy resin, urethane resin, polyimide resin, and unsaturated polyester resin. Additionally, the curable resin may be a room temperature curable resin, a thermocurable 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 styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated product of styrene-butadiene-styrene block copolymer, and hydrogenated product of styrene-isoprene-styrene block copolymer. Additives, etc. can be mentioned. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

It is preferable that the conductive material and the binder resin contain a thermoplastic component or a thermosetting component. The electrically conductive material and the binder resin may contain a thermoplastic component or a thermosetting component. It is preferable that the electrically conductive material and the binder resin contain a thermosetting component. The thermosetting component preferably contains a curable compound that can be cured by heating and a thermosetting agent. The thermal curing agent is preferably a thermal cationic curing initiator. The curable compound curable by heating and the thermosetting agent are used in an appropriate mixing ratio so that the binder resin can be cured. If the binder resin contains a thermal cationic curing initiator, acids are likely to be included in the cured product. However, by using the conductive particles according to the present invention, the connection resistance between electrodes can be kept low.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, and It may contain various additives such as flame retardants.

The above conductive materials can be used as conductive pastes, conductive films, etc. When the electrically conductive material is a conductive film, a film not containing conductive particles may be laminated on the conductive film containing conductive particles. It is preferable that the electrically conductive paste is an anisotropic electrically conductive paste. It is preferable that the conductive film is an anisotropic conductive film.

Among 100% by weight of the conductive material, the content of the binder resin is preferably 10% by weight or more, more preferably 30% by weight or more, further preferably 50% by weight or more, particularly preferably 70% by weight or more, Preferably it is 99.99% by weight or less, more preferably 99.9% by weight or less. If the content of the binder resin is more than the lower limit and less than the upper limit, the conductive particles are efficiently disposed between the electrodes, and the connection reliability of the connection target members connected by the conductive material can be further improved.

In 100% by weight of the electrically conductive material, the content of the electrically 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 or less, and further. Preferably it is 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. If the content of the electroconductive particles is more than the lower limit and less than the upper limit, the reliability of conduction between electrodes can be further improved.

(connection structure)

A connected structure can be obtained by connecting connection target members using the electrically conductive particles or the electrically conductive material containing the electrically conductive particles and 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 conductive particle according to the present invention, or Or, it is preferable that it is a bonded structure which is the electrically-conductive material according to this invention containing the said electroconductive particle and binder resin. It is preferable that the connection portion is formed of the electrically conductive particles according to the present invention, or is formed of the electrically conductive material according to the present invention containing the electrically conductive particles and a binder resin. When electrically conductive particles are used, the connection part itself is an electrically conductive particle. That is, the first and second connection target members are connected by the electroconductive particles.

In Fig. 5, a bonded structure using conductive particles according to the first embodiment of the present invention is schematically shown in front cross-sectional view.

The connection structure 51 shown in FIG. 5 is a connection portion connecting the first connection target member 52, the second connection target member 53, and the first and second connection target members 52 and 53. (54) is provided. The connection portion 54 is formed by hardening the conductive material containing the conductive particles 1. In addition, in FIG. 5, the conductive particles 1 are shown schematically 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 its surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on its surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected by one or more conductive particles 1. Accordingly, 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. An example of the manufacturing method of the connection structure includes arranging the conductive material between the first connection target member and the second connection target member, obtaining a laminate, and then heating and pressurizing the laminate. You can. The pressurizing pressure is approximately 9.8×10 ⁴ to 4.9×10 ⁶ Pa. The heating temperature is approximately 120 to 220°C.

Specific examples of the connection target members include electronic components such as semiconductor chips, condensers, and diodes, and circuit boards such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. It is preferable that the connection target member is an electronic component. The conductive particles are preferably used for electrical connection of electrodes in electronic components.

Examples of electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, silver electrodes, SUS electrodes, molybdenum electrodes, and tungsten electrodes. When the connection target member is a flexible printed circuit board, the electrode is preferably a gold electrode, nickel electrode, tin electrode, or 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 electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal elements include Sn, Al, and Ga.

Hereinafter, the present invention will be described in detail through examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)

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

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

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

A nickel plating solution (2) containing 0.14 mol/L nickel sulfate, 0.03 mol/L sodium tartrate trihydrate, 0.60 mol/L titanium (III) chloride, and 0.15 mol/L sodium gluconate (pH 8). .0) was prepared.

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

Thereafter, the suspension 2 is filtered to remove the particles, washed with water, and dried to form a conductive layer (thickness of 0.1 μm) containing nickel on the surface of the substrate particle A, and the surface is a conductive layer. particles were obtained.

(Example 2)

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

(Example 3)

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

(Example 4)

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

(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 dimethylamineborane.

(Example 6)

0.46 mol/L of dimethylamine borane in the nickel plating solution (1) was changed to 1.40 mol/L of sodium hypophosphite, and 0.60 mol/L of titanium(III) chloride in the nickel plating solution (2) was changed to 1.40 mol/L of sodium hypophosphite. Except for changing it to /L, conductive particles were obtained in the same manner as in Example 1.

(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 0.02 mol/L of sodium tartrate trihydrate and 0.10 mol/L of sodium gluconate were added to the nickel plating solution (1).

(Example 9)

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

(Example 10)

The amount of sodium tartrate trihydrate added in the nickel plating solution (2) was changed from 0.03 mol/L to 0.05 mol/L, and the amount of sodium gluconate added in the nickel plating solution (2) was changed from 0.15 mol/L to 0.25 mol/L. Electroconductive particles were obtained in the same manner as in Example 1 except for the changes.

(Example 11)

To the nickel plating solution (1), 0.04 mol/L of sodium tartrate trihydrate and 0.20 mol/L of sodium gluconate were added. The amount of sodium tartrate trihydrate added to the nickel plating solution (2) was 0.03 mol/L to 0.05 mol/L. Conductive particles were obtained in the same manner as in Example 1, except that the addition amount of sodium gluconate in the nickel plating solution (2) was changed from 0.15 mol/L to 0.25 mol/L.

(Example 12)

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

(Example 13)

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

(Example 14)

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

(Example 15)

Substrate particles B, which were different from the substrate particles A only in particle diameter and had a particle diameter of 2.2 μm, were prepared. Except having changed the said substrate particle A into the said substrate particle B, it carried out similarly to Example 1, and obtained electroconductive particle.

(Example 16)

Substrate particle C, which differs from the substrate particle A only in particle diameter and has a particle diameter of 10.0 μm, was prepared. Except having changed the said substrate particle A into the said substrate particle C, it carried out similarly to Example 1, and obtained electroconductive particle.

(Example 17)

300 g of a 0.13% by weight aqueous ammonia solution was placed in a 500 mL reaction vessel equipped with a stirrer and thermometer. Next, a mixture of 4.1 g of methyltrimethoxysilane, 19.2 g of vinyl trimethoxysilane, and 0.7 g of silicon alkoxy oligomer (“X-41-1053” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the ammonia aqueous solution in the reaction vessel. It was added slowly. After the hydrolysis and condensation reactions proceeded with stirring, 2.4 mL of a 25% by weight ammonia aqueous solution was added, the particles were isolated from the ammonia aqueous solution, and the obtained particles were calcined at 350°C for 2 hours at an oxygen partial pressure of 10 ^-17 atm. , organic-inorganic hybrid particles (base particle D) with a particle diameter of 3.0 μm were obtained. Electroconductive particles were obtained in the same manner as in Example 3 except that the substrate particle A was changed to the substrate particle D.

(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% of the total surface area of 100% of the outer surface of the electrically conductive portion.

(Example 19)

In a 1000 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, cooling pipe, and temperature probe, 100 mmol of methyl methacrylate and N,N,N-trimethyl-N-2-methacryloyloxy. A monomer composition containing 1 mmol of ethylammonium chloride and 1 mmol of 2,2'-azobis(2-amidinopropane) dihydrochloride was weighed and added to ion-exchanged water so that the solid content ratio was 5% by weight. After that, it was stirred at 200 rpm, and polymerization was performed at 70°C for 24 hours under a 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 diameter of 220 nm, and a CV value of 10%. The insulating particles were dispersed in ion-exchanged water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of the insulating particles. 10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion-exchanged 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, it was further washed with methanol and dried to obtain conductive particles with attached insulating particles. When observed with a scanning electron microscope (SEM), only one layer of insulating particles was formed on the surface of the conductive particles. The coverage area of the insulating particles (that is, the projected area of the particle diameter of the insulating particles) with respect to an area of 2.5 μm from the center of the conductive particles was calculated through image analysis, and the coverage was 30%.

(Comparative Example 1)

The amount of sodium tartrate trihydrate added in the nickel plating solution (2) was changed from 0.03 mol/L to 0.10 mol/L, and the amount of sodium gluconate added in the nickel plating solution (2) was changed from 0.15 mol/L to 0.35 mol/L. Electroconductive particles were obtained in the same manner as in Example 1 except for the changes.

(Comparative Example 2)

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

(evaluation)

(1) Average content of nickel, tin, and indium in the entire conductive layer containing nickel

5 g of conductive particles were added to a mixed solution of 5 mL of 60% nitric acid and 10 mL of 37% hydrochloric acid, and the conductive layer was completely dissolved to obtain a solution. Using the obtained solution, the contents of nickel, tin, and indium were analyzed using a high-frequency inductively coupled plasma ion source mass spectrometer (“ICP-MS” manufactured by Hitachi Seisakusho Co., Ltd.). Additionally, contents other than nickel, tin, and indium were phosphorus or boron.

(2) Average content of nickel, tin and indium in the thickness direction of the conductive layer containing nickel

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

Thin-film sections of the obtained conductive particles were prepared using a focused ion beam. Nickel, tin, and indium in the thickness direction of the conductive layer containing nickel were measured by energy dispersive X-ray spectrometry (EDS) using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by Nippon Electronics). The content was measured. From these results, the region R1 up to 1/2 the thickness from the inner surface of the conductive layer containing nickel outward (area with a thickness of 50% on the inner surface side), from the outer surface of the conductive layer containing nickel. The region (R2) of up to 1/2 of the thickness toward the inside (area with a thickness of 50% on the outer surface side), and the region (R3) of up to 1/4 of the thickness toward the inside from the outer surface of the conductive layer containing nickel. (25% thickness area on the outer surface side) and the region R4 (outer surface side) between the 1/4 thickness position and the 1/2 thickness position toward the inside from the outer surface of the conductive layer containing nickel. The average content of nickel, tin, and indium in the area (between the 25% thickness position and the 50% thickness position) was determined. Additionally, contents other than nickel, tin, and indium were phosphorus or boron. Additionally, through the above measurement, the content distribution results of nickel, tin, and indium in the thickness direction of the conductive layer containing nickel were obtained. From this result, the maximum value of the total content of tin and indium in the region R3 was obtained.

(3) Melting point of the 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 Chemical Co., Ltd.). As a result, the melting point of the conductive layer in the examples 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 (“Fisher Scope H-100” manufactured by Fisher).

(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)

Manufacturing of the connection structure:

20 parts by weight of an epoxy compound as a thermosetting compound (“EP-3300P” manufactured by Nagase Chemtex), 15 parts by weight of an epoxy compound as a thermosetting compound (“EPICLON HP-4032D” manufactured by DIC Corporation), and a thermal cation generator (Sansshin) as a thermosetting agent. 5 parts by weight of Sun Aid "SI-60" manufactured by Kagaku Co., Ltd. and 20 parts by weight of silica (average particle diameter 0.25 ㎛) as a filler are mixed, and the obtained conductive particles are mixed so that the content of the obtained conductive particles is 10% by weight in 100% by weight of the mixture. After addition, an anisotropic electrically conductive paste was obtained by stirring for 5 minutes at 2000 rpm using a planetary stirrer.

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

An anisotropic conductive paste immediately after production was applied to the upper surface of the glass substrate to a thickness of 20 μm to form an anisotropic conductive material layer. Next, the semiconductor chip was stacked on the upper surface of the anisotropic conductive material layer so that the electrodes faced each other. After that, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer is 170°C, a pressure heating head is placed on the upper surface of the semiconductor chip, a pressure of 2.5 MPa is applied, and the anisotropic conductive material layer is cured at 170°C. A connection structure was obtained.

Measurement of connection resistance:

The connection resistance A between the electrodes facing the obtained connection structure was measured by the four-terminal method. Additionally, the connection resistance A was determined based on the following standards.

[Evaluation criteria for connection resistance A]

○○○: Connection resistance A is 2.0Ω or less.

○○: Connection resistance A exceeds 2.0Ω and is 3.0Ω or less.

○: Connection resistance A exceeds 3.0Ω and is 5.0Ω or less.

△: Connection resistance A exceeds 5.0Ω and is 10Ω or less.

×: Connection resistance A exceeds 10Ω

(7) Connection resistance B (after influence of acid)

The obtained conductive particles were immersed in a 5% sulfuric acid aqueous solution for 30 minutes. After that, the particles were taken out by filtration, washed with water, replaced with ethanol, and left to dry for 10 minutes to obtain conductive particles exposed to acid. Using the obtained electroconductive particles, a bonded structure was manufactured in the same manner as above (6), and the connection resistance B was measured in the same manner as the connection resistance A. Additionally, the connection resistance B was determined based on the following standards.

[Evaluation criteria for connection resistance B]

○○○: Connection resistance B is more than 1 time but less than 1.5 times the connection resistance A.

○○: Connection resistance B is 1.5 times or more but less than 2 times that of connection resistance A.

○: Connection resistance B is more than 2 times but less than 5 times that of connection resistance A.

△: Connection resistance B is more than 5 times but less than 10 times that of connection resistance A.

×: Connection resistance B is 10 times or more than connection resistance A

(8) Connection resistance C (after influence of alkali)

The obtained conductive particles were immersed in a 5% aqueous sodium hydroxide solution for 30 minutes. After that, the particles were taken out by filtration, washed with water, replaced with ethanol, and left to dry for 10 minutes to obtain conductive particles exposed to alkali. Using the obtained electroconductive particles, a bonded structure was manufactured in the same manner as above (6), and the connection resistance C was measured in the same manner as the connection resistance A. Additionally, the connection resistance C was determined based on the following standards.

[Evaluation criteria for connection resistance C]

○○○: Connection resistance C is more than 1 time but less than 1.5 times the connection resistance A.

○○: Connection resistance C is 1.5 times or more but less than 2 times the connection resistance A.

○: Connection resistance C is more than 2 times but less than 5 times the connection resistance A.

△: Connection resistance C is more than 5 times but less than 10 times that of connection resistance A.

×: Connection resistance C is 10 times or more than 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 approximately 800,000), 200 parts by weight of methyl ethyl ketone, and a microcapsule type hardener (Asahi 50 parts by weight of "HX3941HP" manufactured by Kasei Chemicals and 2 parts by weight of a silane coupling agent ("SH6040" manufactured by Toray Dow Corning Silicone Co., Ltd.) were mixed, and conductive particles were added so that the content was 3% by weight, dispersed, and anisotropic conductivity was obtained. Got the ingredients. In addition, three types of anisotropic electrically conductive materials were manufactured using the conductive particles of the three conditions used in connection resistance A, connection resistance B, and connection resistance C.

The three types of anisotropic conductive materials obtained were stored at 25°C for 72 hours. After storage, it was evaluated whether the aggregated conductive particles were settling in the anisotropic conductive material. The state of aggregation was determined based on the following criteria.

[Judgment criteria for aggregation state]

○: Agglomerated conductive particles do not settle in all three types of anisotropic conductive materials.

△: Only one type of anisotropic conductive material is used, and the aggregated conductive particles are settling.

×: Two or more types of anisotropic conductive materials, and the aggregated conductive particles are settling.

The results are shown in Tables 1 to 3 below.

One… conductive particles
2… substrate particles
3… Conductive layer containing nickel
11… conductive particles
11a… spin
12… Conductive layer containing nickel
12a… spin
13… core material
14… insulating material
21… conductive particles
21a… spin
22… Conductive layer containing nickel
22a… spin
22A… first conductive layer
22Aa… spin
22B… second conductive layer
22Ba… spin
51… connection structure
52… Absence of first connection target
52a… first electrode
53… Absence of second connection target
53a… second electrode
54… connection

Claims (9)

Equipped with substrate particles and a conductive layer disposed on the surface of the substrate particles and containing nickel,
The conductive layer containing nickel is an alloy layer containing 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 area from the outer surface of the conductive layer containing nickel to 1/2 the thickness inward,
The average content of the total tin and indium in the area up to 1/2 the thickness from the inner surface of the conductive layer containing nickel toward the outside is 1/2 of the thickness from the outer surface of the conductive layer containing nickel toward the inside. Conductive particles smaller than the total average content of tin and indium in the area up to /2. The method according to claim 1, wherein the total average content of tin and indium in a region up to 1/4 of the thickness toward the inside from the outer surface of the conductive layer containing nickel is Conductive particles that are greater than the average content of the sum of tin and indium in the area between the 1/4th thickness position and the 1/2th thickness position toward the inside. The method according to claim 1 or 2, wherein the maximum total content of tin and indium in 100% by weight of the area from the outer surface of the conductive layer containing nickel to 1/4 of the thickness inward is 50% by weight. Below, conductive particles. The conductive particle according to claim 1 or 2, wherein the conductive layer containing nickel has protrusions on its outer surface. The electroconductive particle according to claim 1 or 2, wherein the electroconductive particle has a volume resistivity of 0.003 Ω·cm or less. The conductive particle according to claim 1 or 2, further comprising an insulating material disposed on the outer surface of the conductive layer containing nickel. An electrically-conductive material containing the electroconductive particle of Claim 1 or 2, and binder resin. A first connection target member,
Absence of a second connection target,
It has a connection part connecting the first connection target member and the second connection target member,
A connected structure in which the material of the connection portion is the conductive particles according to claim 1 or 2, or an electrically conductive material containing the conductive particles and a binder resin. delete

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