WO2015037711A1

WO2015037711A1 - Conductive particles, conducting material, and connection structure

Info

Publication number: WO2015037711A1
Application number: PCT/JP2014/074260
Authority: WO
Inventors: 仁志山際; 昌男笹平
Original assignee: 積水化学工業株式会社
Priority date: 2013-09-12
Filing date: 2014-09-12
Publication date: 2015-03-19
Also published as: KR101614675B1; JPWO2015037711A1; CN105210157A; CN105210157B; JP5719483B1; KR20150099873A

Abstract

Provided are conductive particles capable of lowering the connection resistance when electrodes are electrically connected therebetween. Each conductive particle (1) is provided with a base particle (2), and a conducting portion (3) disposed on the surface of the base particle (2), the conducting portion (3) having a plurality of protrusions (3a) on the external surface, the conducting portion (3) having a crystal structure, and the crystal structure being continuous between a portion where the protrusion (3a) is present and a portion where the protrusion (3a) is not present in the conducting portion (3).

Description

Conductive particles, conductive materials, and connection structures

The present invention relates to conductive particles comprising base particles and conductive portions arranged on the surface of the base particles, and the conductive portions having a plurality of protrusions on the outer surface. The present invention also relates to a conductive material and a connection structure using the conductive particles.

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

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

As an example of the conductive particles, Patent Document 1 below discloses conductive particles having core material particles (base material particles) and a metal or alloy film on the surface of the core material particles. . The conductive particles have a plurality of protrusions protruding from the surface of the film. The protrusion is composed of a particle connected body in which a plurality of metal or alloy particles are connected in a row. In Examples and Comparative Examples of Patent Document 1, conductive particles having a ratio of the connecting protrusions of 32% or more are shown.

The following Patent Document 2 discloses conductive particles in which a nickel conductive layer or a nickel alloy conductive layer is formed on the surface of spherical base particles having an average particle diameter of 1 to 20 μm by an electroless plating method. The conductive particles have minute protrusions of 0.05 to 4 μm on the outermost layer of the conductive layer. The conductive layer and the protrusion are substantially continuously connected. Resin particles are used as the substrate particles.

JP 2012-113850 A JP 2000-243132 A

In recent years, it has been required to reduce the power consumption of electronic devices. For this reason, the property which can make the connection resistance between the electrodes electrically connected by the electroconductive particle further lower is required for the electroconductive particle.

However, when the electrodes are electrically connected using conventional conductive particles as described in

Patent Documents

1 and 2, the connection resistance may increase.

An oxide film is often formed on the surface of the electrode and the surface of the conductive particles. In the conductive particles described in

Patent Literatures

1 and 2, when the electrodes are connected, the protrusions are easily broken, and as a result, the protrusions may not sufficiently penetrate the oxide film. For this reason, the connection resistance between electrodes may become high.

An object of the present invention is to provide conductive particles capable of reducing connection resistance when electrodes are electrically connected. Another object of the present invention is to provide a conductive material and a connection structure using the conductive particles.

According to a wide aspect of the present invention, the method includes a base particle and a conductive portion disposed on a surface of the base particle, the conductive portion has a plurality of protrusions on an outer surface, and the conductive portion is a crystal. Provided is a conductive particle having a structure in which a crystal structure is continuous between a portion having the protrusion and a portion having no protrusion in the conductive portion.

In a specific aspect of the conductive particle according to the present invention, the conductive portion is formed of a metal or a metal alloy, and the protrusion includes a plurality of the metal or metal alloy particles connected in a row. A plurality of first protrusions formed of the metal or metal alloy, and the protrusions are formed by connecting a plurality of particles of the metal or metal alloy in a row. At least one second protrusion formed by a particle connected body in which a plurality of particles of the metal or metal alloy are connected in a row does not have the second protrusion formed by the particle connected body. 70% or more of the total number of the first protrusions and the second protrusions of 100% is the first protrusions.

In a specific aspect of the conductive particle according to the present invention, 90% or more of 100% of the total number of the first protrusions and the second protrusions is the first protrusions.

In a specific aspect of the conductive particle according to the present invention, the crystallite size in the conductive part is 0.1 nm or more and 100 nm or less.

In a specific aspect of the conductive particle according to the present invention, the crystal lattice distortion in the conductive part is 0.0001% or more and 10% or less.

In a specific aspect of the conductive particle according to the present invention, the conductive part contains nickel.

In a specific aspect of the conductive particle according to the present invention, the conductive particle does not have a core material for raising the outer surface of the conductive part inside and inside the conductive part.

In a specific aspect of the conductive particle according to the present invention, the height of the protrusion is 1/100 or more of the particle diameter of the conductive particle.

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

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

According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the A connection portion connecting the second connection target member, and the connection portion is formed of the above-described conductive particles or formed of a conductive material including the conductive particles and a binder resin. There is provided a connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.

The conductive particles according to the present invention include base particles and conductive portions arranged on the surfaces of the base particles, the conductive portions have a plurality of protrusions on the outer surface, and the conductive portions are crystals. Since the crystal structure is continuous between the portion having the protrusion and the portion without the protrusion in the conductive portion, the electrodes are electrically connected using the conductive particles according to the present invention. In this case, the connection resistance can be lowered.

FIG. 1 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to the third embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

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

(Conductive particles)
The electroconductive particle which concerns on this invention is equipped with base material particle and the electroconductive part arrange | positioned on the surface of the said base material particle. In the conductive particles according to the present invention, the conductive portion has a plurality of protrusions on the outer surface. In the conductive particles according to the present invention, the conductive portion has a crystal structure. In the electroconductive particle which concerns on this invention, the crystal structure is continuing in the part with the said protrusion in the said electroconductive part, and the part without the said protrusion.

By adopting the above-described configuration of the conductive particles according to the present invention, the connection resistance can be lowered when the electrodes are electrically connected using the conductive particles according to the present invention. The reason for this is considered to be that the projection becomes relatively hard as a result of the crystal structure being continuous and becoming hard and having high spreadability.

In the present invention, from the viewpoint of reducing the connection resistance between the electrodes, the conductive portion has a crystal structure, and the crystal structure is continuous between the portion where the protrusion is present and the portion where the protrusion is not present in the conductive portion. . The portion without the protrusion is the first portion of the conductive portion, and the portion with the protrusion is the second portion that is thicker than the first portion. In the first portion, the outer surface of the conductive portion is not raised.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the crystallite size in the conductive part is preferably 0.1 nm or more, more preferably 1.73 nm or more, still more preferably 5 nm or more, preferably 100 nm or less, more Preferably it is 50 nm or less, More preferably, it is 10 nm or less. The reason for this is that if the crystallite size of the conductive part is not less than the above lower limit and not more than the above upper limit, the protrusion becomes relatively hard as a result of becoming harder and further spreading. . In the conductive part satisfying the above crystallite size, the protrusions are not easily broken when the electrodes are connected, and the protrusions are hardly damaged. In the present invention, by forming the conductive portion satisfying the above crystallite size, the protrusion sufficiently penetrates the oxide film on the surface of the electrode or the conductive particle, so that the connection resistance between the electrodes is further reduced. be able to.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the crystal lattice distortion in the conductive part is preferably 0.001% or more, more preferably 0.01% or more, still more preferably 0.1% or more, particularly Preferably it is 0.15% or more, Preferably it is 10% or less, More preferably, it is 5% or less, More preferably, it is 1% or less.

In order to optimize the crystallite size, the continuity of the crystal structure and the crystal lattice distortion in the conductive particles according to the present invention, the ratio of the metal to be co-deposited with respect to the main metal, the plating reaction, Optimization of speed, optimization of pH in the plating bath, optimization of temperature in the plating bath, and the like are appropriately performed.

The method for making the crystallite size in the conductive part finer is to make it finer by increasing the phosphorus content in the nickel conductive part, making it finer by increasing the boron content in the nickel conductive part, and organic luster in the plating solution. Examples thereof include a method of refining by adding an agent and a method of refining by adding a metallic brightener. In particular, an increase in the content of phosphorus and boron in the nickel-plated conductive part and the addition of an organic brightener are effective in reducing the crystallite size in the conductive part.

As a method of increasing the phosphorus and boron contents in the nickel plating conductive part, the method of lowering the pH of the plating solution to slow the reaction rate of the nickel plating solution, the method of lowering the temperature of the nickel plating solution, Examples thereof include a method of increasing the concentration of the phosphorus-based reducing agent and the boron-based reducing agent, and a method of increasing the concentration of the complexing agent in the nickel plating solution. As for these methods, only 1 type may be used and 2 or more types may be used together.

Examples of the organic brightener include saccharin, sodium naphthalene disulfonate, sodium naphthalene trisulfonate, sodium allyl sulfonate, sodium propargyl sulfonate, butynediol, propargyl alcohol, coumarin, formalin, ethoxylated polyethyleneimine, polyalkyl Examples include imine, polyethyleneimine, gelatin, dextrin, thiourea, polyvinyl alcohol, polyethylene glycol, polyacrylamide, cinnamic acid, nicotinic acid, and benzalacetone. As for the said organic type brightener, only 1 type may be used and 2 or more types may be used together.

Furthermore, preferred examples of the organic brightener include ethoxylated polyethyleneimine, polyalkylimine, polyethyleneimine, and polyethylene glycol.

Examples of a method for reducing the crystal lattice distortion in the conductive part include a method of adding a metal stabilizer to the plating solution. Addition of the metal stabilizer improves the stability of the plating solution, lowers the crystal lattice distortion, and forms a plating film with good coverage on the substrate particles. Examples of the metal stabilizer include lead compounds, bismuth compounds, thallium compounds, and vanadium compounds. Specific examples of the metal stabilizer include sulfates, carbonates, acetates, nitrates and hydrochlorides of metals (lead, bismuth, thallium, vanadium) constituting the compound. In consideration of the influence on the environment, a bismuth compound, a thallium compound or a vanadium compound is preferable.

The height of the protrusions in the conductive particles is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the height of the protrusion is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes is effectively reduced. The height of the protrusion is an average of the heights of a plurality of protrusions per conductive particle. The height of the projection is a virtual line of the conductive portion (dashed line shown in FIG. 1) on the assumption that there is no projection on the line (dashed line L1 shown in FIG. 1) connecting the center of the conductive particles and the tip of the projection. L2) Indicates the distance from the top (on the outer surface of the spherical conductive particles assuming no projection) to the tip of the projection. That is, in FIG. 1, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion is shown.

From the viewpoint of effectively reducing the connection resistance and effectively increasing the connection reliability between the electrodes, the height of the protrusion is preferably 1/100 or more of the particle diameter of the conductive particles. / 15 or more is more preferable. The height of the protrusion is preferably 1/6 or less of the particle diameter of the conductive particles. In all the examples described later, the height of the protrusion is not less than 1/15 and not more than 1/6 of the particle diameter of the conductive particles.

The number of the protrusions per 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. Of the total surface area of 100% of the outer surface of the conductive part, the surface area of the portion having the protrusion is preferably 30% or more, more preferably 50% or more.

The protrusions are not formed by connecting a plurality of particles of the metal or metal alloy in a row, and have a plurality of first protrusions formed of the metal or metal alloy. May be. The protrusion does not have a second protrusion formed by a particle connected body in which a plurality of particles of the metal or metal alloy are connected in a row, or the particles of the metal or metal alloy are in a row At least one second protrusion formed by a particle connected body connected to a plurality of particles may be provided. In the conductive particles according to the present invention, it is preferable that 70% or more of the total number of the first protrusions and the second protrusions is 70% or more. In this case, the connection resistance between the electrodes is further reduced. However, less than 70% of the total number of 100% of the first protrusions and the second protrusions may be the first protrusions, and even in that case, the protrusions in the conductive part The effect of the present invention can be obtained if the crystal structure is continuous between the portion having the protrusion and the portion having no protrusion.

The second protrusion is more likely to be broken or damaged when connected between the electrodes than the first protrusion. For this reason, the ratio of the first protrusions to the total number of the first protrusions and the second protrusions decreases (for example, less than 70%), and the ratio of the second protrusions decreases. When it increases (for example, 30% or more), the projections do not sufficiently penetrate the oxide film on the surface of the electrode or the conductive particles, and the connection resistance between the electrodes tends to increase. On the other hand, since the ratio of the first protrusions in the total number of the first protrusions and the second protrusions is large, the protrusions form an oxide film on the surface of the electrode or the conductive particles. In order to sufficiently penetrate, the connection resistance between the electrodes can be further reduced.

Conductive particles having a plurality of protrusions on the outer surface of the conductive part are known. Japanese Patent Application Laid-Open No. 2012-113850 discloses conductive particles having protrusions made of a particle connected body in which a plurality of metal or alloy particles are connected in a row. In the examples and comparative examples of Japanese Patent Application Laid-Open No. 2012-113850, conductive particles in which the proportion of the connecting protrusions is 32% or more are shown. However, in the conductive particles having such connecting projections, if the proportion of the connecting projections is relatively large, the connection resistance between the electrodes may not be sufficiently low. On the other hand, in the conductive particles according to the present invention, the connection resistance between the electrodes can be sufficiently lowered because there is no connection protrusion or the ratio of the connection protrusion is small.

The first protrusion is not formed by connecting a plurality of particles of the metal or metal alloy in a row, and is formed of the metal or metal alloy. The first protrusion is a protrusion other than the particle connected body. The second protrusion is formed of a particle connected body in which a plurality of particles of the metal or metal alloy are connected in a row. The protrusion is formed by both the first protrusion and the second protrusion. The individual particles constituting the second protrusion and the particle connected body are formed of a metal or metal alloy forming a conductive portion. The first protrusion and the second protrusion may have a shape in which protrusions branched into linear portions are mixed. Regarding the number of branches and the form of branching, they may be bifurcated or multi-branched, and may be dendritic.

From the viewpoint of further reducing the connection resistance between the electrodes, the ratio of the number of the first protrusions to the total number of the first protrusions and the second protrusions of 100% is more preferably 80. % Or more, more preferably 90% or more, particularly preferably 95% or more, and the ratio of the number of the second protrusions is more preferably less than 30%, still more preferably less than 20%, and particularly preferably less than 10%. Most preferably, it is less than 5%.

The ratio of the second protrusions in the total number of 100% of the first protrusions and the second protrusions may be 1% or more, and the ratio of the first protrusions is 99%. It may be the following.

The first protrusion and the second protrusion are counted as follows.

The magnification is set to 25000 times with a scanning electron microscope (SEM), 10 particles are randomly selected, and the protrusions of each particle are observed. For all of the protrusions, the metal or metal alloy particles are not formed by connecting a plurality of particles in a row, and the protrusion is formed of a metal or metal alloy, and the metal or metal alloy. The particles are separated into protrusions formed by a particle connected body in which a plurality of particles are connected in a row. Whether or not a plurality of metal or metal alloy particles are connected can be determined by whether or not a grain boundary is observed between the metal or metal alloy particles.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the height of the first protrusion is preferably 0.5 times or more the thickness of the portion of the conductive portion where the protrusion is not present. It is more preferably at least twice, more preferably at least 3 times, more preferably at most 10 times, and even more preferably at most 7 times. The height of the first protrusion is an average of the height of the first protrusion per one conductive particle.

When the height of the first protrusion is assumed that there is no first protrusion on the line connecting the center of the conductive particles and the tip of the first protrusion (broken line L1 shown in FIG. 1) The distance from the imaginary line (broken line L2 shown in FIG. 1) of the conductive portion (on the outer surface of the spherical conductive particles when it is assumed that there is no first protrusion) to the tip of the first protrusion Show. That is, in FIG. 1, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the first protrusion is shown. When the first protrusion is a branched protrusion, the tip of the first protrusion is the tip of the protrusion that is farthest from the outer surface of the conductive particles.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the width of the first protrusion is preferably 0.1 times or more the thickness of the portion of the conductive part where the protrusion is not provided. It is more preferably 5 times or more, more preferably 1 time or more, further preferably 5 times or less, and more preferably 3 times or less. The width of the first protrusion is the maximum diameter in a direction orthogonal to the height direction of the first protrusion.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the height of the second protrusion is preferably 0.5 times or more the thickness of the portion of the conductive portion where the protrusion is absent. It is more preferably at least twice, more preferably at least 3 times, more preferably at most 10 times, and even more preferably at most 7 times. The height of the second protrusion is the average of the height of the second protrusion per conductive particle.

The height of the second protrusion is defined in the same manner as the height of the first protrusion. That is, the height of the second projecting portion is on the imaginary line of the conductive portion when it is assumed that there is no second projecting portion on the line connecting the center of the conductive particles and the tip of the second projecting portion ( The distance from the outer surface of the spherical conductive particles (assuming that there is no second protrusion) to the tip of the second protrusion is shown. When the second protrusion is a branched protrusion, the tip of the second protrusion is the tip of the protrusion that is farthest from the outer surface of the conductive particles.

From the viewpoint of effectively reducing the connection resistance between the electrodes, the width of the second protrusion is preferably 0.1 times or more the thickness of the portion of the conductive portion where the protrusion is not provided. It is more preferably 5 times or more, more preferably 1 time or more, further preferably 5 times or less, and more preferably 3 times or less. The width of the second protrusion is the maximum diameter in a direction orthogonal to the height direction of the second protrusion.

The particle diameter of the metal or metal alloy particles constituting the second protrusion is preferably 10 nm or more, more preferably 20 nm or more, preferably 500 nm or less, more preferably 400 nm or less. When the particle diameter of the metal or metal alloy particles constituting the second protrusion is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes is further reduced. The particle diameter of the metal or metal alloy particles constituting the second protrusion means the maximum diameter.

Specifically, the first protrusion is a protrusion that is not formed by connecting a plurality of particles of metal or metal alloy in a row, and is observed with a scanning electron microscope (SEM). The protrusion is different from the protrusion in which the grain boundary is confirmed between the particles of the metal or metal alloy.

In the second protrusion, grain boundaries are observed between particles of the metal or metal alloy when observed with a scanning electron microscope (SEM). This fact confirms that the second protrusion is formed by connecting a plurality of particles of the metal or metal alloy. In the first protrusion, no grain boundary is observed in the metal or metal alloy.

The first protrusion and the second protrusion are discriminated by a scanning electron microscope (SEM). The first protrusion is not a particle connected body because there is no grain boundary.

The plurality of the metal or metal alloy particles are connected in a row to form the second protrusion. With respect to being connected in a row, it means that a plurality of particles of the metal or metal alloy are connected so as to extend in a certain direction. For example, the second protrusion may be configured by linearly connecting a plurality of particles of the metal or metal alloy, and has a meandering shape by connecting the plurality of particles of the metal or metal alloy. The second protrusion may be formed. Moreover, the linear part and the meandering part may be mixed. Further, the second protrusion may be branched into a plurality of portions from the base on the conductive portion side to the tip. For example, the second protrusion may be Y-shaped. When attention is paid to one conductive particle, the shapes of the plurality of second protrusions present may be the same or different.

In the plurality of second protrusions, the number of particles of the metal or metal alloy may be the same or different. The second protrusion is configured by connecting at least two particles of the metal or metal alloy in a row. The number of connected particles of the metal or metal alloy in the second protrusion is 2 or more, preferably 30 or less, more preferably 20 or less, still more preferably 5 or less, and particularly preferably 3 or less. The number of particles of the metal or metal alloy constituting the second protrusion is measured by observing the second protrusion with a scanning electron microscope (SEM).

From the viewpoint of further improving the connection resistance between the electrodes, the total number of the first protrusions and the second protrusions per conductive particle is preferably 5 or more, more preferably 10 or more, more preferably 20 or more, preferably 1000 or less, more preferably 500 or less, and still more preferably 300 or less.

Examples of a method for making the first protrusion more easily formed than the second protrusion include a method using a high molecular weight complexing agent and a method using a sulfur-based stabilizer. By using a high molecular weight complexing agent, the size of the complex increases, the complex becomes difficult to enter between the plurality of protrusions, and only the protrusions can be selectively grown.

Compression modulus when the conductive particles are compressed 10% (10% K value) is preferably 1000 N / mm ² or more, more preferably 5000N / mm ² or more, more preferably 6300N / mm ² or more, preferably 20000N / Mm ² or less, more preferably 16000 N / mm ² or less. When the 10% K value is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes is effectively reduced.

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

Using a micro-compression tester, the conductive particles are compressed under the conditions of a smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) at 25 ° C., a compression rate of 0.3 mN / second, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

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

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

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 500 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 10 μm or less. It is. When the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrode becomes sufficiently large when the electrodes are connected using the conductive particles, and the conductive part When forming the conductive particles, it becomes difficult to form aggregated conductive particles. Further, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portion is difficult to peel from the surface of the base particle.

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

Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings. In the referenced drawings, the size and thickness are appropriately changed from the actual size and thickness for convenience of illustration. Note that different partial configurations in the respective embodiments can be appropriately replaced and combined.

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

1 has a base particle 2 and a conductive portion 3 disposed on the surface of the base particle 2. The conductive particle 1 shown in FIG. In the conductive particles 1, the conductive part 3 is a conductive layer. The conductive part 3 covers the surface of the base particle 2. The conductive particle 1 is a coated particle in which the surface of the base particle 2 is coated with the conductive portion 3.

The conductive particles 1 have a plurality of protrusions 1a on the conductive surface. The conductive portion 3 has a plurality of protrusions 3a on the outer surface.

The conductive portion 3 has a first portion and a second portion that is thicker than the first portion. Accordingly, the conductive portion 3 has a protrusion 3a on the surface (the outer surface of the conductive layer). A portion excluding the plurality of protrusions 1 a and 3 a is the first portion of the conductive portion 3. The plurality of protrusions 1a and 3a are the second portions where the conductive portion 3 is thick.

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

2 has a base particle 2 and a conductive portion 3A disposed on the surface of the base particle 2. The conductive particle 1A shown in FIG. The conductive portion 3A is a conductive layer. Only the presence or absence of the core substance 4 is different between the conductive particles 1 and the conductive particles 1A. The conductive particles 1A have a core substance.

The conductive particle 1 A has a plurality of core substances 4 on the surface of the base particle 2. The conductive portion 3 A covers the base particle 2 and the core substance 4. By covering the core material 4 with the conductive portion 3A, the conductive particles 1A have a plurality of protrusions 1Aa on the surface, and the conductive portion 3A has a plurality of protrusions 3Aa on the outer surface. The surface of the conductive portion 3A is raised by the core substance 4, and a plurality of protrusions 1Aa are formed.

A core material may be used to form the protrusions 1Aa and 3Aa like the conductive particles 1A, but it is preferable not to use a core material.

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

3 has a base particle 2A, a conductive portion 3B disposed on the surface of the base particle 2A, and an insulating substance 5. The conductive particle 1B shown in FIG. The conductive part 3B is a conductive layer. The conductive part 3B has a first conductive part 3Bx disposed on the surface of the base particle 2A and a second conductive part 3By disposed on the surface of the first conductive part 3Bx.

The base particle 2A is an organic-inorganic hybrid particle. The base particle 2A has an organic core 2Ax and an inorganic shell 2Ay disposed on the surface of the organic core 2Ax.

The conductive particles 1B have protrusions 1Ba on the conductive surface. The conductive particles 1B have protrusions 1Ba on the surface. The conductive portion 3B has a protrusion 3Ba on the surface (the outer surface of the conductive layer). The second conductive portion 3By has a first portion and a second portion that is thicker than the first portion. Accordingly, the second conductive portion 3By has the protrusion 3Bya on the surface (the outer surface of the conductive layer). A portion excluding the plurality of protrusions 3Bya is the first portion of the second conductive portion 3By. The plurality of protrusions 3Bya are the second portions where the thickness of the second conductive portion 3By is thick.

Like the conductive particles 1B, the conductive portion 3B may have a multilayer structure. Further, in order to form the protrusions 1Ba and 3Ba, the core material 4 is disposed on the first conductive portion 3Bx of the inner layer, and the core material 4 and the first conductive portion 3Bx are separated by the second conductive portion 3By of the outer layer. It may be coated.

The conductive particle 1B includes an insulating material 5 disposed on the outer surfaces of the conductive portion 3B and the second conductive portion 3By. At least a part of the outer surface of the conductive portion 3B and the second conductive portion 3By is covered with the insulating material 5. The insulating substance 5 is made of an insulating material and is an insulating particle. Thus, the electroconductive particle which concerns on this invention may have the insulating substance arrange | positioned on the outer surface of an electroconductive part.

In the

conductive particles

1, 1 A, 1 B described above, the

conductive portions

3, 3 A, 3 By have a crystal structure, the

conductive portions

3, 3 A, 3 By have protrusions 3 a, 3 Aa, 3 Bya and protrusions 3 a, 3 Aa, 3 Bya. The crystal structure is continuous with the part where there is no. In the conductive particles 1, 1A, 1B described above, the crystallite size in the conductive portions 3, 3A, 3By is preferably 0.1 nm or more, and preferably 100 nm or less.

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

[Base material particles]
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles. The base particles may be core-shell particles.

The base material particles are more preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. By using these preferable base particles, conductive particles more suitable for electrical connection between the electrodes can be obtained.

When connecting the electrodes using the conductive particles, the conductive particles are compressed by placing the conductive particles between the electrodes and then pressing them. When the substrate particles are resin particles or organic-inorganic hybrid particles, the conductive particles are easily deformed during the pressure bonding, and the contact area between the conductive particles and the electrode is increased. For this reason, the connection resistance between electrodes becomes still lower.

Various organic substances are suitably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; Alkylene terephthalate, 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, polysulfone, polyphenylene Oxide, polyacetal, polyimide, polyamideimide, polyether ether Tons, polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. Resin for forming the resin particles can be designed and synthesized, and the hardness of the base particles can be easily controlled within a suitable range, which is suitable for conductive materials and having physical properties at the time of compression. Is preferably a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups.

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

Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; acids such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate Atom-containing (meth) acrylates; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; Vinyl acetates such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

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

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

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

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

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

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

When the substrate particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

The particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, further preferably 2 μm or more, preferably 30 μm or less, more preferably 10 μm or less. The particle diameter of the substrate particles may be 5 μm or less, or 3 μm or less. When the particle diameter of the substrate particles is not less than the above lower limit and not more than the above upper limit, even when the distance between the electrodes is small and the thickness of the conductive portion is increased, small conductive particles can be obtained.

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

[Conductive part]
The thickness of the conductive part without the protrusion is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, more preferably 0.3 μm or less. When the thickness of the portion without the protrusion of the conductive portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity can be obtained, and the conductive particles do not become too hard and are electrically conductive during connection between the electrodes. The particles are sufficiently deformed.

When the conductive portion is formed of a plurality of layers, the thickness of the portion of the outermost conductive layer where the protrusions are not present is preferably 0.005, particularly when the outermost layer is a gold layer. It is 001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably 0.1 μm or less. When the thickness of the portion of the outermost conductive layer where the protrusion is not present is not less than the lower limit and not more than the upper limit, the coating with the outermost conductive layer becomes uniform, corrosion resistance is sufficiently high, and the distance between the electrodes The connection resistance is sufficiently low.

The thickness of the conductive part without the protrusion can be measured by observing a cross section of the conductive particle using, for example, a transmission electron microscope (TEM).

Examples of the method for forming the conductive part on the surface of the substrate particle include a method for forming the conductive part by electroless plating and a method for forming the conductive part by electroplating.

The conductive part preferably contains a metal. The metal that is the material of the conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. Further, tin-doped indium oxide (ITO) may be used as the metal. These metals may be alloyed in the conductive part. However, an appropriate metal is selected so that the degree of crystallinity in the conductive portion is not less than the above lower limit and not more than the above upper limit. As for the said metal, only 1 type may be used and 2 or more types may be used together.

From the viewpoint of effectively reducing the connection resistance between the electrodes and controlling the crystallinity in the conductive part to a more suitable range, the conductive part preferably contains copper or nickel, and contains nickel. Is preferred. In this case, a metal such as nickel may be alloyed with another metal. The material of the conductive part is preferably copper, copper alloy, nickel or nickel alloy, and more preferably nickel or nickel alloy.

In 100% by weight of the conductive part having a plurality of protrusions on the outer surface, the content of copper or nickel is preferably 10% by weight or more, more preferably 25% by weight or more, still more preferably 40% by weight or more, preferably 100% by weight. % (Total amount) or less. It is preferable that the content of nickel in the conductive part is not less than the above lower limit and not more than the above upper limit.

The conductive part preferably contains nickel as a main metal. The content of nickel is preferably 50% by weight or more in 100% by weight of the entire conductive part including nickel. In 100% by weight of the conductive part containing nickel, the content of nickel is preferably 65% by weight or more, more preferably 80% by weight or more, and further preferably 90% by weight or more. When the nickel content is at least the above lower limit, the connection resistance between the electrodes is further reduced.

From the viewpoint of further reducing the connection resistance between the electrodes, the conductive portion containing nickel preferably contains phosphorus or boron, and more preferably contains phosphorus. The content of phosphorus is preferably more than 0% by weight, more preferably 0.1% by weight or more, still more preferably 2% by weight or more, particularly preferably 5% by weight or more, in 100% by weight of the entire conductive part including nickel. Most preferably it exceeds 10% by weight, preferably 20% by weight or less, more preferably 15% by weight or less. When the phosphorus content is not less than the above lower limit and not more than the above upper limit, the connection resistance is further lowered. In particular, when the phosphorus content is 5% by weight or more, the reliability of the connection resistance is further increased, and when the phosphorus content exceeds 10% by weight, the adhesion is improved and the reliability of the connection resistance is improved. It gets even higher.

As a method for controlling the content of nickel, boron and phosphorus in the conductive part, for example, when forming the conductive part by electroless nickel plating, a method for controlling the pH of the nickel plating solution, conductive by electroless nickel plating. A method for adjusting the concentration of a boron-containing reducing agent when forming a part, a method for adjusting the concentration of a phosphorus-containing reducing agent when forming a conductive part by electroless nickel plating, and a nickel concentration in a nickel plating solution The method etc. of adjusting are mentioned.

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

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

As a method of forming the catalyst on the surface of the resin particles, for example, after adding the resin particles to a solution containing palladium chloride and tin chloride, the surface of the resin particles is activated with an acid solution or an alkali solution, A method of depositing palladium on the surface of the resin particles, and after adding the resin particles to a solution containing palladium sulfate and aminopyridine, the surface of the resin particles is activated by a solution containing a reducing agent. Examples thereof include a method of depositing palladium on the surface. As the reducing agent, a phosphorus-containing reducing agent is preferably used. In addition, a conductive layer containing boron can be formed by using a boron-containing reducing agent as the reducing agent.

In the electroless plating step, a nickel plating bath containing a nickel-containing compound and the phosphorus-containing reducing agent is preferably used. By immersing the resin particles in the nickel plating bath, nickel can be deposited on the surface of the resin particles on which the catalyst is formed, and a conductive layer containing nickel and phosphorus can be formed.

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

Examples of the phosphorus-containing reducing agent include sodium hypophosphite. Examples of the boron-containing reducing agent include dimethylamine borane, sodium borohydride, and potassium borohydride.

[Core material]
Since the core substance is embedded in the conductive portion, it is easy for the conductive portion to have a plurality of protrusions on the outer surface. However, in order to form protrusions on the surfaces of the conductive particles and the conductive part, the core material is not necessarily used, and it is preferable not to use the core material. It is preferable that the conductive particles do not have a core substance for raising the outer surface of the conductive part inside and inside the conductive part. It is preferable that the conductive part does not include a core material for raising the outer surface of the conductive part inside and inside the conductive part. It is preferable that a conductive part having protrusions on the outer surface is formed on the surface of the spherical base particle without using a core substance.

As a method for forming protrusions on the surface of the conductive particles, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the base particles, and electroless plating on the surface of the base particles Examples include a method of forming a conductive part by, attaching a core substance, and further forming a conductive part by electroless plating. As another method for forming the protrusion, a first conductive part is formed on the surface of the base particle, and then a core substance is disposed on the first conductive part, and then the second conductive part. And a method of adding a core substance in the middle of forming a conductive part on the surface of the base particle.

As a method of arranging the core substance on the surface of the base particle, for example, the core substance is added to the dispersion of the base particle, and the core substance is applied to the surface of the base particle, for example, van der Waals force. And a method in which a core substance is added to a container containing base particles, and a core substance is attached to the surface of the base particles by mechanical action such as rotation of the container. . Especially, since the quantity of the core substance to adhere is easy to control, the method of making a core substance accumulate and adhere on the surface of the base particle in a dispersion liquid is preferable.

The material of the core substance includes a conductive substance and a non-conductive substance. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the nonconductive material include silica, alumina, and zirconia. Especially, in order to improve the penetration effect of an oxide film, it is preferable that the core substance is hard. The core substance is preferably metal particles. As the metal that is the material of the core substance, the metals mentioned as the material of the conductive material can be used as appropriate.

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

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

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

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

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

[Insulating material]
It is preferable that the electroconductive particle which concerns on this invention is equipped with the insulating substance arrange | positioned on the outer surface of the said electroconductive part. In this case, when the conductive particles are used for connection between the electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact with each other, an insulating material is present between the plurality of electrodes, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. It should be noted that the insulating material between the conductive portion of the conductive particles and the electrode can be easily removed by pressurizing the conductive particles with the two electrodes when connecting the electrodes. Since the conductive portion has a plurality of protrusions on the outer surface, the insulating material between the conductive portion of the conductive particles and the electrode can be easily excluded.

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

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

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

As a method of disposing an insulating substance on the surface of the conductive part, there are a chemical method, a physical or mechanical method, and the like. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. In particular, since the insulating substance is difficult to be detached, a method in which the insulating substance is disposed on the surface of the conductive portion via a chemical bond is preferable.

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

The average diameter (average particle diameter) of the insulating material can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles, and the like. 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, more preferably 0.5 μm or less. When the average diameter of the insulating material is equal to or more than the above lower limit, when the conductive particles are dispersed in the binder resin, the conductive portions in the plurality of conductive particles are difficult to contact each other. When the average diameter of the insulating particles is not more than the above upper limit, it is not necessary to make the pressure too high in order to eliminate the insulating material between the electrodes and the conductive particles when the electrodes are connected, There is no need for heating.

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

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

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

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

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

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

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

In 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, still more preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.% or more. It is 99 weight% or less, More preferably, it is 99.9 weight% or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further increased.

In 100% by weight of the conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 40% by weight or less, more preferably 20% by weight or less, More preferably, it is 10 weight% or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further enhanced.

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

The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion has the above-described conductivity. The connection structure is preferably formed of particles or formed of a conductive material containing the above-described conductive particles and a binder resin. In the case where conductive particles are used, the connection portion itself is conductive particles. That is, the first and second connection target members are connected by the conductive particles.

FIG. 4 is a cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

4 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 that connects the first and second

connection target members

52 and 53. Prepare. The connection portion 54 is formed by curing a conductive material including the conductive particles 1. The connection part 54 includes the conductive particles 1 and the binder resin 54a. In FIG. 4, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, conductive particles 1A, 1B, etc. may be used.

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

connection target members

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

The manufacturing method of the connection structure is not particularly limited. As an example of the manufacturing method of the connection structure, the conductive material is disposed between the first connection target member and the second connection target member to obtain a laminate, and then the laminate is heated and pressurized. Methods and the like. The pressurizing pressure is about 9.8 × 10 ⁴ to 4.9 × 10 ⁶ Pa. The heating temperature is about 120 to 220 ° C. The pressure applied to connect the electrode of the flexible printed board, the electrode disposed on the resin film, and the electrode of the touch panel is about 9.8 × 10 ⁴ to 1.0 × 10 ⁶ Pa.

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

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

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

Example 1
(1) Production of Conductive Particles As substrate particles A, divinylbenzene copolymer resin particles (“Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 3.0 μm were prepared.

The resin particles were taken out by dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and then filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

The suspension was put into a solution of nickel sulfate 0.09 mol / L, thallium nitrate 30 ppm and bismuth nitrate 20 ppm to obtain a particle mixture (A).

Separately, nickel plating containing nickel sulfate 0.23 mol / L, dimethylamine borane 0.92 mol / L, sodium citrate 0.25 mol / L, sodium tungstate 0.05 mol / L, thallium nitrate 140 ppm, and bismuth nitrate 30 ppm Liquid (B) (pH 8.0) was prepared.

The nickel plating solution (B) was gradually added dropwise to the dispersed particle mixture (A) adjusted to 40 ° C. to perform electroless nickel plating. The dropping rate of the nickel plating solution (B) was set to 10 ml / min. During the dropping of the nickel plating solution (B), nickel plating was performed while dispersing the generated Ni protrusion nuclei by ultrasonic stirring.

Thereafter, the suspension is filtered to remove the particles, washed with water, and dried to place a nickel-boron conductive layer (thickness 0.1 μm) on the surface of the resin particles, and the outer surface has protrusions. Conductive particles as a conductive layer were obtained.

(2) Production of anisotropic conductive material 7 parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, 30 parts by weight of phenol novolac type epoxy resin, SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) was blended and defoamed and stirred for 3 minutes to obtain an anisotropic conductive paste.

(3) Production of Connection Structure A transparent glass substrate having an IZO electrode pattern (first electrode, metal Vickers hardness of 100 Hv on the electrode surface) having an L / S of 10 μm / 20 μm was prepared. Further, a semiconductor chip was prepared in which an Au electrode pattern (second electrode, metal Vickers hardness of 50 Hv on the electrode surface) having L / S of 10 μm / 20 μm was formed on the lower surface.

(Example 2)
Conductive particles were produced in the same manner as in Example 1 except that the nickel sulfate concentration in the nickel plating solution (B) was changed from 0.23 mol / L to 0.46 mol / L. In this way, a nickel-boron conductive layer (thickness 0.2 μm) was arranged on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained.

An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

Example 3
Conductive particles were produced in the same manner as in Example 1 except that the pH of the nickel plating solution (B) was changed from 8.0 to 6.0. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

Example 4
Conductive particles were produced in the same manner as in Example 1 except that the dropping rate of the nickel plating solution (B) was changed to 1/2. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 5)
Conductive particles were produced in the same manner as in Example 1 except that 140 ppm of thallium nitrate in the nickel plating solution (B) was changed to 200 ppm of vanadium dioxide. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 6)
After dispersing 10 parts by weight of the resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the resin particles were taken out by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% by weight dimethylamine borane solution to activate the surface of the resin particles. The resin particles whose surface was activated were sufficiently washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

Nickel plating solution containing nickel sulfate 0.23 mol / L, dimethylamine borane 0.92 mol / L, sodium citrate 0.25 mol / L, sodium tungstate 0.05 mol / L, thallium nitrate 140 ppm, and bismuth nitrate 30 ppm (B) (pH 8.0) was prepared.

Also, a plating solution for forming a protrusion (C) (pH 10.0) containing dimethylamine borane 2.0 mol / L and sodium hydroxide 0.05 mol / L was prepared.

The nickel plating solution (B) was gradually added dropwise to the dispersed particle mixture (A) adjusted to 40 ° C. to perform electroless nickel plating. The dropping rate of the nickel plating solution (B) was set to 10 ml / min. During the dropping of the nickel plating solution (B), nickel plating was performed while dispersing the generated Ni protrusion nuclei by ultrasonic stirring. Thereafter, in order to form protrusions on the conductive layer, the protrusion forming plating solution (C) was gradually dropped to form protrusions. The dropping rate of the projection forming plating solution (C) was set to 2 ml / min. During the dropping of the projection forming plating solution (C), nickel plating was performed while dispersing the generated Ni projection nuclei by ultrasonic stirring.

Thereafter, the suspension is filtered to remove the particles, washed with water, and dried to place a nickel-boron conductive layer (thickness 0.1 μm) on the surface of the resin particles, and the outer surface has protrusions. Conductive particles as a conductive layer were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 7)
Conductive particles were obtained in the same manner as in Example 6, except that only the particle diameter was different from that of the substrate particle A and the particle diameter was changed to the substrate particle B of 2.5 μm. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 8)
Conductive particles were obtained in the same manner as in Example 6 except that only the particle diameter was different from that of the substrate particle A and the particle diameter was changed to the substrate particle C of 10.0 μm. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

Example 9
The surface of divinylbenzene copolymer resin particles having a particle diameter of 2.0 μm (“Micropearl SP-202” manufactured by Sekisui Chemical Co., Ltd.) was coated with a silica shell (thickness 250 nm) using a condensation reaction by a sol-gel reaction. Core-shell type organic-inorganic hybrid particles (base material particles D) were obtained. Except having changed the said base material particle A into the said base material particle D, it carried out similarly to Example 6, and obtained electroconductive particle. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 10)
In a 500 mL reaction vessel equipped with a stirrer and a thermometer, 300 g of a 0.13% by weight aqueous ammonia solution was placed. Next, 4.1 g of methyltrimethoxysilane, 19.2 g of vinyltrimethoxysilane, and 0.7 g of silicone alkoxy oligomer (“X-41-1053” manufactured by Shin-Etsu Chemical Co., Ltd.) in an aqueous ammonia solution in the reaction vessel. The mixture with was added slowly. After the hydrolysis and condensation reaction proceeded with stirring, 2.4 mL of a 25 wt% aqueous ammonia solution was added, and then the particles were isolated from the aqueous ammonia solution, and the resulting particles were subjected to an oxygen partial pressure of 10 ⁻¹⁷ atm. And calcination at 350 ° C. for 2 hours to obtain organic-inorganic hybrid particles (base particle E) having a particle size of 2.5 μm. Conductive particles were obtained in the same manner as in Example 6 except that the base particle A was changed to the base particle E. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 11)
To a 1000 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser and temperature probe, 100 mmol of methyl methacrylate and N, N, N-trimethyl-N-2-methacryloyloxyethyl A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchanged water so that the solid content was 5% by weight, and then at 200 rpm. The mixture was stirred and polymerized 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 size of 220 nm, and a CV value of 10%.

The insulating particles were dispersed in ion exchange water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

10 g of the conductive particles obtained in Example 6 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, the particles were further washed with methanol and dried to obtain conductive particles having insulating particles attached thereto.

When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. The coverage of the insulating particles with respect to the area of 2.7 μm from the center of the conductive particles by image analysis (that is, the projected area of the particle diameter of the insulating particles) was calculated to be 30%.

Example 12
Conductive particles were prepared in the same manner as in Example 6 except that sodium citrate 0.25 mol / L in the nickel plating solution (B) was changed to disodium malonate 0.5 mol / L. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Example 13)
Conductive particles were produced in the same manner as in Example 6 except that sodium citrate 0.25 mol / L in the nickel plating solution (B) was changed to sodium propionate 1.0 mol / L. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Comparative Example 1)
Dimethylamine borane 0.92 mol / L in the nickel plating solution (B) was changed to 1.38 mol / L sodium hypophosphite, and the plating solution for projection formation (C) dimethylamine borane 2.0 mol / L Example 6 except that sodium hypophosphite was changed to 2.18 mol / L, and sodium citrate 0.25 mol / L in the nickel plating solution (B) was changed to sodium tartrate 0.3 mol / L. Similarly, conductive particles were produced. In this way, a nickel-phosphorus conductive layer (thickness 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Comparative Example 2)
Conductive particles were produced in the same manner as in Example 6 except that the protrusion forming plating solution (C) was dropped without performing ultrasonic stirring. In this way, a nickel-boron conductive layer (thickness: 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Comparative Example 3)
Using metal nickel particle slurry (“2020SUS” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter of 150 nm), the metal nickel particles are attached to the surface of the resin particles used in Example 1, and then a conductive layer is formed to conduct electricity. Forming protrusions on the outer surface of the part, changing dimethylamine borane 0.92 mol / L in the nickel plating solution (B) to 1.38 mol / L sodium hypophosphite, and a plating solution for forming the protrusions (C) Except for changing 2.0 mol / L of dimethylamine borane to 2.18 mol / L of sodium hypophosphite, the conductive layer is formed in the same manner as in Example 6, and the outer surface has protrusions. Conductive conductive particles as a conductive layer were produced. In this way, a nickel-phosphorus conductive layer (thickness 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

(Comparative Example 4)
Dimethylamine borane 0.92 mol / L in the nickel plating solution (B) was changed to 1.38 mol / L sodium hypophosphite, and the plating solution for projection formation (C) dimethylamine borane 2.0 mol / L Example 6 except that sodium hypophosphite was changed to 2.18 mol / L and that sodium citrate 0.25 mol / L in the nickel plating solution (B) was changed to sodium propionate 1.0 mol / L In the same manner, conductive particles were produced. In this way, a nickel-phosphorus conductive layer (thickness 0.1 μm) was disposed on the surface of the resin particles, and conductive particles whose outer surface was a conductive layer having protrusions were obtained. An anisotropic conductive material and a connection structure were produced in the same manner as in Example 1 using the obtained conductive particles.

In all of the above Examples and Comparative Examples, the height of the protrusion was 1/15 or more and 1/6 or less of the particle diameter of the conductive particles.

(Evaluation)
(1) Crystallite size Using an X-ray diffractometer (“RINT2500VHF” manufactured by Rigaku Corporation), the conductive part under the conditions of tube voltage 40 kV, tube current 50 mA, X-ray: CuKα ray, and wavelength λ: 1.541Å The crystallite size was measured.

(2) Crystal lattice distortion Using an X-ray diffractometer (“RINT2500VHF” manufactured by Rigaku Corporation), a conductive part under the conditions of tube voltage 40 kV, tube current 50 mA, X-ray: CuKα ray, and wavelength λ: 1.541Å. The crystal lattice distortion in was measured.

(3) State of protrusions Using a scanning electron microscope (SEM), the image magnification was set to 25000 times, 10 conductive particles were randomly selected, and the protrusions of each conductive particle were observed. . All the protrusions are evaluated by whether or not grain boundaries are observed between particles of metal or metal alloy, and are not formed by connecting a plurality of particles of metal or metal alloy in a row. And a protrusion (first protrusion) formed of a metal or metal alloy and a protrusion (first protrusion) formed of a particle linking body in which a plurality of particles of metal or metal alloy are connected in a row. 2 protrusions). Thus, 1) the number of first protrusions and 2) the number of second protrusions per one conductive particle were measured. The ratio of the first and second protrusions in the total number of 100% of the first and second protrusions was calculated.

(4) Confirmation of crystal structure (continuity)
Using a field emission transmission electron microscope (FE-TEM) (“JEM-ARM200F” manufactured by JEOL Ltd.), the presence or absence of crystal grain boundaries in the conductive portion having a plurality of protrusions on the outer surface was evaluated at 5 million times. In addition, it was evaluated whether or not the crystal structure was continuous between the portion with the protrusion and the portion without the protrusion in the conductive portion.

(5) Compressive elastic modulus of conductive particles (10% K value)
The 10% K value of the conductive particles was measured using a micro-compression tester (“Fischer Scope H-100” manufactured by Fischer) according to the method described above under the condition of 23 ° C.

(6) Connection resistance between electrodes The connection resistance between the upper and lower electrodes of the obtained connection structure was measured by a four-terminal method, respectively. The average value of the two connection resistances was calculated. Note that the connection resistance can be obtained by measuring the voltage when a constant current is passed from the relationship of voltage = current × resistance. The connection resistance between the electrodes was determined according to the following criteria.

[Criteria for connection resistance between electrodes]
○○○: Connection resistance is 2.0Ω or less ○○: Connection resistance is over 2.0Ω, 3.0Ω or less ○: Connection resistance is over 3.0Ω, 5.0Ω or less Δ: Connection resistance is 5.0Ω Exceeding 10Ω ×: Connection resistance exceeds 10Ω

(7) Projection Height Using a scanning electron microscope (SEM), set the image magnification to 25000 times, select 10 conductive particles randomly, and observe the projections of each conductive particle did. The height of the protrusion in the obtained conductive particles was measured.

The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Conductive particle 1a, 1Aa, 1Ba ... Protrusion 2, 2A ... Base particle 2Ax ... Organic core 2Ay ... Inorganic shell 3, 3A, 3B ... Conductive part 3a, 3Aa ... Protrusion 3Bx ... First conductivity Part 3By ... second conductive part 3Bya ... protrusion 4 ... core substance 5 ... insulating substance 51 ... connection structure 52 ... first connection object member 52a ... first electrode 53 ... second connection object member 53a ... first 2 electrode 54 ... connection part 54a ... binder resin

Claims

Substrate particles,
A conductive portion disposed on the surface of the base particle,
The conductive part has a plurality of protrusions on the outer surface;
The conductive portion has a crystal structure;
Conductive particles in which a crystal structure is continuous between a portion where the protrusion is present and a portion where the protrusion is not present in the conductive portion.
The conductive part is formed of a metal or a metal alloy;
The protrusion is not formed by connecting a plurality of particles of the metal or metal alloy in a row, and has a plurality of first protrusions formed of the metal or metal alloy;
The protrusion does not have a second protrusion formed by a particle linking body in which a plurality of particles of the metal or metal alloy are connected in a row, or the particles of the metal or metal alloy are in a row And having at least one second protrusion formed by a particle linking body connected to a plurality of particles,
2. The conductive particle according to claim 1, wherein 70% or more of a total number of 100% of the first protrusions and the second protrusions is the first protrusions.
The conductive particles according to claim 2, wherein 90% or more of 100% of the total number of the first protrusions and the second protrusions is the first protrusions.
The conductive particle according to any one of claims 1 to 3, wherein a crystallite size in the conductive part is 0.1 nm or more and 100 nm or less.
The conductive particle according to any one of claims 1 to 4, wherein a crystal lattice strain in the conductive part is 0.001% or more and 10% or less.
The conductive particle according to any one of claims 1 to 5, wherein the conductive portion contains nickel.
The conductive particles according to any one of claims 1 to 6, which do not have a core substance for raising the outer surface of the conductive part inside and inside the conductive part.
The conductive particle according to any one of claims 1 to 7, wherein a height of the protrusion is 1/100 or more of a particle diameter of the conductive particle.
The conductive particles according to any one of claims 1 to 8, comprising an insulating substance disposed on an outer surface of the conductive part.
A conductive material comprising the conductive particles according to any one of claims 1 to 9 and a binder resin.
A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connecting portion is formed of the conductive particles according to any one of claims 1 to 9, or is formed of a conductive material containing the conductive particles and a binder resin.
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles.