TWI768068B - Electroconductive particle, method for producing electroconductive particle, conductive material, and connection structure - Google Patents

Abstract

The present invention provides an electroconductive particle which can effectively improve the conduction reliability between electrodes and can effectively prevent the breakage of the electroconductive portion due to external impact. The electroconductive particle of this invention contains a base material particle, the 1st electroconductive part arrange|positioned on the surface of the said base material particle, and the 2nd electroconductive part arrange|positioned on the surface of the said 1st electroconductive part, and is examined by the electron microscope. When the outer surface of the second conductive part is observed, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or pinholes with a size of 50 nm or more in the maximum longitudinal direction at 1/μm ² or less.

Description

Electroconductive particle, method for producing electroconductive particle, conductive material, and connection structure

The present invention relates to an electroconductive particle that can be used, for example, for electrical connection between electrodes. Moreover, this invention relates to the manufacturing method of the said electroconductive particle, the electroconductive material using the said electroconductive particle, and a connection structure.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin. Moreover, the electroconductive particle by which the surface of a conductive layer was insulated may be used as electroconductive particle.

The above-mentioned anisotropic conductive material is used to obtain various connection structures. Examples of the connection using the above-mentioned anisotropic conductive material include connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass, coated glass)), connection between a semiconductor chip and a flexible printed circuit board (COF) (Chip on Film), the connection between semiconductor chips and glass substrates (COG (Chip on Glass, chip on glass)), and the connection between flexible printed substrates and glass epoxy substrates (FOB (Film on Board) , Coated plate)) and so on.

As an example of the said electroconductive particle, the electroconductive particle provided with the base material particle and the electroconductive metal layer which coat|covers the surface of this base material particle is disclosed in following patent document 1. The said base material particle is a polymer particle whose glass transition temperature (Tg) is 50 degreeC or more and 100 degreeC or less. The thickness of the conductive metal layer is 0.01 μm~0.15 μm. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-064559

[Problems to be Solved by Invention]

In recent years, with the development of various electronic devices, the materials of substrates are also diversified. For example, a curved panel or a flexible panel that can be bent freely has been developed. Since the above-mentioned curved panels and the like require flexibility, plastic substrates such as polyimide substrates have been studied to replace the conventional glass substrates as flexible members for curved panels and the like.

When a semiconductor chip is directly mounted on a plastic substrate, the plastic substrate is easily deformed or damaged due to the temperature or pressure during mounting, so the temperature or pressure during mounting must be extremely low. When the temperature or pressure at the time of mounting is lowered, the conductive particles cannot be sufficiently deformed at the time of conductive connection between electrodes. As a result, it may be difficult to sufficiently secure the contact area between the electroconductive particles and the electrode. In addition, there is a case where a phenomenon called springback occurs because the compressed conductive particles try to return to their original shape. When rebound occurs, it may be difficult to sufficiently maintain the contact area between the conductive particles and the electrode. As a result, the conduction reliability between electrodes may decrease.

Moreover, by using the conventional electroconductive particle as described in patent document 1, even when the temperature and the pressure at the time of mounting are low, it becomes possible to exhibit high connection reliability to some extent. However, among such electroconductive particles, since the base material particles are relatively soft, cracks (cracks in the conductive portion) may easily occur in the electroconductive metal layer due to external impact. It is difficult for conventional conductive particles to prevent breakage of the conductive portion due to external impact.

The objective of this invention is to provide the electroconductive particle which can improve the conduction reliability between electrodes effectively, and can prevent the breakage of the electroconductive part by external impact effectively. Moreover, this invention provides the manufacturing method of the said electroconductive particle, the electroconductive material using the said electroconductive particle, and a connection structure. [Technical means to solve problems]

According to a broad aspect of the present invention, there is provided an electroconductive particle comprising: a substrate particle; a first conductive portion arranged on the surface of the substrate particle; and a second conductive portion arranged on the first conductive portion described above On the outer surface of the conductive part; and when the outer surface of the second conductive part is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or there are ¹ pinhole/μm2 or less. The size in the length direction is a pinhole of 50 nm or more.

According to a broad aspect of the present invention, there is provided an electroconductive particle comprising: a substrate particle; a first conductive portion arranged on the surface of the substrate particle; and a second conductive portion arranged on the first conductive portion described above On the outer surface of the conductive part; and when the outer surface of the second conductive part is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or there are ¹ pinhole/μm2 or less. The size in the longitudinal direction is a pinhole of 50 nm or more and 200 nm or less.

In a specific aspect of the electroconductive particle of this invention, the said electroconductive particle satisfy|fills the relation of following formula (1), and the compression recovery rate in 25 degreeC is 10 % or less.

A≦5500-B×100 Formula (1)

In the said formula (1), A is the 10% K value (N/mm< ² >) of the said electroconductive particle, and B is the average particle diameter (micrometer) of the said electroconductive particle.

In a specific aspect of the electroconductive particle of this invention, an average particle diameter is 3 micrometers or more and 30 micrometers or less.

In a specific aspect of the electroconductive particle of this invention, the said 2nd electroconductive part contains gold, silver, palladium, platinum, copper, cobalt, ruthenium, indium, or tin.

In a specific aspect of the electroconductive particle of this invention, the ionization tendency of the metal contained in the said 1st electroconductive part is larger than the ionization tendency of the metal contained in the said 2nd electroconductive part.

In a specific aspect of the electroconductive particle of this invention, the said 1st electroconductive part contains nickel and phosphorus.

In a specific aspect of the electroconductive particle of this invention, in the thickness direction of the said 1st electroconductive part, the phosphorus content of the said 2nd electroconductive part side in the said 1st electroconductive part is more than the said 1st electroconductive part The content of phosphorus on the side of the above-mentioned substrate particles in the part.

According to a broad aspect of the present invention, there is provided a method for producing electroconductive particles, comprising the steps of: using electroconductive particles provided with substrate particles and a first conductive portion disposed on the surface of the substrate particles, by A second conductive portion is disposed on the outer surface of the first conductive portion by plating treatment; and the second conductive portion is formed in such a manner that when the outer surface of the second conductive portion is observed with an electron microscope, there is no Pinholes with a size of 50 nm or more in the maximum longitudinal direction, or pinholes with a size of 50 nm or more in the maximum longitudinal direction exist at a rate of 1/μm ² or less.

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

According to a broad aspect of the present invention, there is provided a connection structure including: a first connection target member having a first electrode on a surface; a second connection target member having a second electrode on the surface; and a connection portion, It connects the said 1st connection object member and the said 2nd connection object member; The material of the said connection part is the said electroconductive particle, or the electroconductive material containing the said electroconductive particle and the binder resin; Two electrodes are electrically connected by the said electroconductive particle. [Effect of invention]

The electroconductive particle of this invention is provided with the base material particle, the 1st electroconductive part arrange|positioned on the surface of the said base material particle, and the 2nd electroconductive part arrange|positioned on the outer surface of the said 1st electroconductive part. In the conductive particles of the present invention, when the outer surface of the second conductive portion is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or 1 pinhole/μm ² or less. The size of the largest length direction is a pinhole of 50 nm or more. Since the electroconductive particle of this invention has the said structure, the conduction reliability between electrodes can be improved effectively, and the crack of the electroconductive part by external impact can be prevented effectively.

The electroconductive particle of this invention is provided with the base material particle, the 1st electroconductive part arrange|positioned on the surface of the said base material particle, and the 2nd electroconductive part arrange|positioned on the outer surface of the said 1st electroconductive part. In the conductive particles of the present invention, when the outer surface of the second conductive portion is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or 1 pinhole/μm ² or less. The size in the maximum length direction is a pinhole of 50 nm or more and 200 nm or less. Since the electroconductive particle of this invention has the said structure, the conduction reliability between electrodes can be improved effectively, and the crack of the electroconductive part by external impact can be prevented effectively.

The manufacturing method of the electroconductive particle of this invention comprises the process of using the electroconductive particle provided with the base material particle and the 1st electroconductive part arrange|positioned on the surface of the said base material particle, and performing a plating process on the said 1st electroconductive part. The second conductive portion is arranged on the outer surface. In the manufacturing method of the electroconductive particle of this invention, the said 2nd electroconductive part is formed so that when the outer surface of the said 2nd electroconductive part is observed with an electron microscope, there is no dimension in the maximum longitudinal direction of 50 nm. The above pinholes, or there are pinholes with a size of 50 nm or more in the maximum longitudinal direction at 1/μm ² or less. Since the manufacturing method of the electroconductive particle of this invention has the said structure, the conduction reliability between electrodes can be improved effectively, and the crack of the electroconductive part by external impact can be prevented effectively.

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

(Electroconductive particle) The electroconductive particle of this invention is equipped with the base material particle; The 1st electroconductive part arrange|positioned on the surface of the said base material particle; And the 2nd electroconductive part arrange|positioned on the surface of the said 1st electroconductive part . In the electroconductive particles of the present invention, when the outer surface of the second conductive portion is observed with an electron microscope, it is preferable that there are no pinholes having a size of 50 nm or more in the maximum longitudinal direction, or that the number of pinholes is 1/μm ² or less. There are pinholes with a size of 50 nm or more in the maximum length direction. In this case, in the electroconductive particle of this invention, when the said pinhole exists, the number of objects of the said pinhole counted per 1 micrometer ² is 1 or less. In the electroconductive particle of this invention, the dimension of the largest longitudinal direction of the said pinhole counted is 50 nm or more.

In the electroconductive particles of the present invention, when the outer surface of the second conductive portion is observed with an electron microscope, it is preferable that there are no pinholes having a size of 50 nm or more in the maximum longitudinal direction, or that the number of pinholes is 1/μm ² or less. There are pinholes whose size in the maximum length direction is 50 nm or more and 200 nm or less. In this case, in the electroconductive particle of this invention, the number of objects of the said pinhole counted per 1 micrometer ² is 1 or less. In the electroconductive particle of this invention, the dimension of the maximum longitudinal direction of the said pinhole is 50 nm or more and 200 nm or less.

Since the present invention has the above-mentioned configuration, the conduction reliability between electrodes can be effectively improved, and the breakage of the conductive portion due to external impact can be effectively prevented.

In order to obtain a connection structure with high connection reliability even under the conditions of low temperature or pressure during installation, it is necessary to use conductive particles having relatively soft substrate particles. However, the conductive particles having relatively soft base particles are easily broken in the conductive portion due to external impact. The inventors of the present invention have made efforts to suppress the breakage of the conductive portion due to external impact, and as a result, found that the cause of the breakage of the conductive portion due to the external shock is due to the replacement gold plating treatment of the conductive portion where the conductive particles are formed. resulting pinholes. The inventors of the present invention found that, in the conductive particles having relatively soft substrate particles, the breakage of the conductive portion due to the external impact occurs from the pinhole as a starting point. Since the present invention has the above-described configuration, it is possible to effectively prevent breakage of the conductive portion due to external impact.

The above-mentioned pinholes are formed by elution of nickel in the form of ions when the second conductive portion is formed on the surface of the first conductive portion formed by nickel plating by, for example, displacement gold plating. For example, due to the elution of the metal in the first conductive portion, the missing portion of the first conductive portion is a pinhole.

In the electroconductive particle of this invention, when observing the outer surface of the said 2nd electroconductive part with an electron microscope, it is preferable that the size of the maximum longitudinal direction does not exist the pinhole of 50 nm or more.

In the electroconductive particle of this invention, when the outer surface of the said 2nd electroconductive part is observed with an electron microscope, when the said pinhole exists, the dimension which exists in the maximum longitudinal direction is ¹ piece/μm2 or less is 50. Pinholes above nm. Preferably, when the outer surface of the second conductive portion is observed with an electron microscope, the number of pinholes having a size of 50 nm or more in the maximum longitudinal direction is preferably 0.1/μm ² or less. When the number of the above-mentioned pinholes is in the above-mentioned preferred range, the conduction reliability between the electrodes can be more effectively improved, and the breakage of the conductive portion due to external impact can be more effectively prevented.

In the electroconductive particle of this invention, when observing the outer surface of the said 2nd electroconductive part with an electron microscope, it is preferable that the size of the maximum longitudinal direction does not exist pinholes of 50 nm or more and 200 nm or less.

In the electroconductive particle of this invention, when the outer surface of the said 2nd electroconductive part is observed with an electron microscope, when the said pinhole exists, the dimension which exists in the maximum longitudinal direction is ¹ piece/μm2 or less is 50. Pinholes above nm and below 200 nm. From the viewpoint of more effective improvement of conduction reliability between electrodes and the viewpoint of more effective prevention of breakage of the conductive portion due to external impact, the maximum length of the above-mentioned pinhole having a dimension in the maximum longitudinal direction is 50 nm or more. The dimension of the direction is preferably 150 nm or less, more preferably 100 nm or less. Preferably, when the outer surface of the second conductive portion is observed with an electron microscope, the number of pinholes having a size of 50 nm or more and 200 nm or less in the maximum longitudinal direction is preferably 0.1/μm ² or less. When the number of the above-mentioned pinholes is in the above-mentioned preferred range, the conduction reliability between the electrodes can be more effectively improved, and the breakage of the conductive portion due to external impact can be more effectively prevented.

The presence or absence of the said pinhole can be confirmed by observing arbitrary electroconductive particle with an electron microscope, for example. Specifically, the presence or absence of the above-mentioned pinholes can be confirmed by observing 5 arbitrary sites with an electron microscope, except for the portion excluding the portion 0.5 μm inward from the outer periphery of any electroconductive particle.

The dimension of the maximum longitudinal direction of the said pinhole can be computed by observing arbitrary electroconductive particle with an electron microscope, for example. The dimension in the maximum longitudinal direction of the pinhole is the distance that connects two points on the outer periphery of the pinhole with a straight line, and the distance that connects the two points on the outer periphery of the pinhole with a straight line becomes the largest dimension.

The shape of the said pinhole is not specifically limited. The shape of the above-mentioned pinhole may be a circular shape or a shape other than a circular shape. When the shape of the above-mentioned pinhole is a circular shape, the dimension of the largest longitudinal direction of the above-mentioned pinhole corresponds to the largest diameter.

In general, when the conductive portion is formed by electroless plating or the like, there are cases where a minute region where the conductive portion is not formed is formed. The maximum lengthwise dimension of such a region is generally less than 50 nm, and in the present invention, such a smaller region is not included in the above-mentioned pinhole.

It is preferable that the said electroconductive particle satisfy|fills the relationship of following formula (1) from a viewpoint of improving the conduction|electrical_connection reliability between electrodes more effectively.

A≦5500-B×100 Formula (1)

In the said formula (1), A is the 10% K value (N/mm< ² >) of the said electroconductive particle, and B is the average particle diameter (micrometer) of the said electroconductive particle.

From the viewpoint of more effectively improving the conduction reliability between electrodes, the 10% K value of the conductive particles is preferably 500 N/mm ² or more, more preferably 1000 N/mm ² or more, and more preferably 4500 N/mm ² or less, more preferably 4000 N/mm ² or less.

The 10% K value of the said electroconductive particle (compression elastic modulus at the time of compressing electroconductive particle by 10%) can be measured by the following method.

Using a micro-compression tester, use the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) to compress 1 conductive particle under the conditions of a compression speed of 0.33 mN/sec and a maximum test load of 20 mN at 25°C . Measure the load value (N) and the compression displacement (mm) at this time. From the obtained measured values, the 10% K value (10% compressive elastic modulus) at 25°C can be determined by the following formula. As the above-mentioned micro-compression testing machine, for example, "micro-compression testing machine MCT-W200" manufactured by Shimadzu Corporation, "Fischer Scope H-100" manufactured by Fischer Corporation, and the like can be used. It is preferable that the 10% K value at 25 degreeC of the said electroconductive particle is computed by averaging the 10% K value at 25 degreeC of 50 electroconductive particles selected arbitrarily.

10% K value (N/mm ² )=(3/2 ^1/2 )・F・S ^-3/2・R ^-1/2 F: The load value of the conductive particles when they are 10% compressed and deformed (N) S: Compression displacement of conductive particles when 10% compressive deformation (mm) R: Radius of conductive particles (mm)

The above K value generally and quantitatively represents the hardness of the conductive particles. By using the above K value, the hardness of the electroconductive particles can be quantitatively and uniquely represented.

From the viewpoint of more effectively improving conduction reliability between electrodes, the compression recovery rate at 25° C. of the conductive particles is preferably 10% or less, more preferably 8% or less. The lower limit of the compression recovery rate at 25° C. of the conductive particles is not particularly limited. The compression recovery rate in 25 degreeC of the said electroconductive particle may be 3% or more.

The compression recovery rate in 25 degreeC of the said electroconductive particle can be measured as follows.

The conductive particles are scattered on the sample stage. For one scattered conductive particle, a micro-compression tester was used, and the end face of the cylinder (diameter 100 μm, made of diamond) was used to smooth the indenter at 25°C in the direction of the center of the conductive particle, with a particle size of 10 When the particle size exceeds 10 μm, a load of up to 50 mN (reversal load value) is applied, and when the particle size is less than 10 μm, a load of up to 10 mN (reversal load value) is applied. After that, unload to the origin with a load value (0.40 mN). The load-compression displacement during the period can be measured, and the compression recovery rate at 25°C can be obtained according to the following formula. In addition, the load speed was set to 0.33 mN/sec. As the above-mentioned micro-compression testing machine, "micro-compression testing machine MCT-W200" manufactured by Shimadzu Corporation, "Fischer Scope H-100" manufactured by Fischer Corporation, and the like are used, for example.

Compression recovery rate (%)=[L2/L1]×100 L1: Compression displacement from the load value at the origin to the reverse load value when the load is applied L2: The difference between the load value from the reverse load value and the load value at the origin when the load is released unload displacement

Since the said electroconductive particle has the said compression characteristic, the electroconductive particle can be used for the electroconductive connection application of a bending part favorably. When the said electroconductive particle is used for the electrically-conductive connection application of a bent part, especially excellent conduction reliability can be exhibited effectively.

Since the said electroconductive particle has the said compression characteristic, it can be used suitably for the electroconductive connection use of the electrode of a flexible member, and can be used for the electroconductive connection use of the electrode of the flexible member in a bent state more preferably. By using the said electroconductive particle, it can exhibit high conduction reliability, and can use a flexible member in a bent state.

As a connection structure using a flexible member, a flexible panel etc. are mentioned. Flexible panels can be used as curved panels. It is preferable that the said electroconductive particle is a connection part for forming a flexible panel, and it is preferable that it is a connection part for forming a curved panel.

The average particle size of the conductive particles is preferably 3 μm or more, more preferably 5 μm or more, still more preferably 7 μm or more, particularly preferably 10 μm or more, and preferably 1000 μm or less, more preferably 100 μm Hereinafter, it is further preferably 30 μm or less, particularly preferably 25 μm or less, and most preferably 20 μm or less. When the average particle diameter of the said electroconductive particle is 3 micrometers or more and 30 micrometers or less, the electroconductive particle can be used for the electroconductive connection use favorably. If the average particle diameter of the said electroconductive particle is more than the said minimum and below the said upper limit, the connection resistance between electrodes can be reduced more effectively, and the conduction reliability between electrodes can be improved more effectively.

It is more preferable that the average particle diameter of the said electroconductive particle is a number average particle diameter. The average particle diameter of the above-mentioned electroconductive particles is obtained by, for example, observing 50 arbitrary electroconductive particles with an electron microscope or an optical microscope, calculating the average value, or calculating the measurement result obtained by a laser diffraction particle size distribution measuring apparatus several times. to find the average value.

The coefficient of variation of the particle diameter of the conductive particles is preferably as low as possible, and is usually 0.1% or more, preferably 10% or less, more preferably 8% or less, and still more preferably 5% or less. The conduction reliability can be further improved as the coefficient of variation of the particle diameter of the electroconductive particles is more than or equal to the above lower limit and less than or equal to the above upper limit. However, the coefficient of variation of the particle diameter of the conductive particles may be less than 5%.

The above-mentioned coefficient of variation (CV value) can be measured in the following manner.

CV value (%)=(ρ/Dn)×100 ρ: Standard deviation of particle size of conductive particles Dn: Average value of particle size of conductive particles

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

Next, specific embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and the following embodiments may be appropriately modified, improved, or the like to such an extent that the characteristics of the present invention are not impaired. In addition, in the reference drawing, for convenience of illustration, the size and thickness are appropriately changed from the actual size and thickness.

FIG. 1 is a cross-sectional view showing an electroconductive particle according to a first embodiment of the present invention.

The electroconductive particle 1 shown in FIG. 1 is provided with the base material particle 2, the 1st electroconductive part 3, and the 2nd electroconductive part 4. The first conductive parts 3 are arranged on the surfaces of the base particles 2 . The second conductive portion 4 is arranged on the surface of the first conductive portion 3 . The first conductive portion 3 is arranged between the base material particles 2 and the second conductive portion 4 . The first conductive parts 3 are in contact with the surfaces of the base particles 2 . The first conductive parts 3 cover the surfaces of the base particles 2 . The second conductive portion 4 is in contact with the surface of the first conductive portion 3 . The second conductive portion 4 covers the surface of the first conductive portion 3 . The electroconductive particle 1 is a coating particle which coat|covers the surface of the base material particle 2 with the 1st electroconductive part 3 and the 2nd electroconductive part 4. The second conductive portion 4 is located on the outermost surface of the conductive portion and is the outermost layer. In the electroconductive particle 1, a multilayer electroconductive part is formed.

The existence state of the pinholes of the electroconductive particle 1 shown in FIG. 1 satisfy|fills the said structure.

In the electroconductive particle 1, the 1st electroconductive part 3 covers the whole surface of the base material particle 2, and forms a conductive layer. The said 1st conductive part may cover the whole surface of the said base material particle, and may not cover the whole surface of the said base material particle. The said 1st conductive part may form the conductive layer which covers the whole surface of the said base material particle, and may not form the conductive layer which covers the whole surface of the said base material particle. The above-mentioned first conductive portion may also be a conductive layer. The said electroconductive particle may have the area|region which the said base material particle is not covered with the said 1st electroconductive part.

In the electroconductive particle 1, the 2nd electroconductive part 4 covers the whole surface of the 1st electroconductive part 3, and forms a conductive layer. The second conductive portion may cover the entire surface of the first conductive portion, or may not cover the entire surface of the first conductive portion. The second conductive portion may form a conductive layer covering the entire surface of the first conductive portion, or may not form a conductive layer covering the entire surface of the first conductive portion. The second conductive portion may be a conductive layer. The said electroconductive particle may have the area|region which the said 1st electroconductive part is not covered with the said 2nd electroconductive part.

The electroconductive particle 1 does not have a core substance. The electroconductive particle 1 does not have a processus|protrusion on the outer surface of an electroconductive part. The electroconductive particle 1 is spherical. The first conductive portion 3 and the second conductive portion 4 do not have protrusions on the outer surfaces. Thus, the electroconductive particle of this invention may not have a processus|protrusion on the surface of an electroconductive part, and may be spherical. Moreover, the electroconductive particle 1 does not have an insulating substance. However, the electroconductive particle 1 may have the insulating substance arrange|positioned on the outer surface of the 2nd electroconductive part 4.

Moreover, in the electroconductive particle 1, the 1st electroconductive part 3 is laminated|stacked on the surface of the base material particle 2 directly. In the said electroconductive particle, another electroconductive part may be arrange|positioned between the said base material particle and the said 1st electroconductive part. In the said electroconductive particle, the said 1st electroconductive part may be arrange|positioned via another electroconductive part on the surface of the said base material particle.

It is sectional drawing which shows the electroconductive particle which concerns on 2nd Embodiment of this invention.

The electroconductive particle 21 shown in FIG. 2 is provided with the base material particle 2, the 1st electroconductive part 22, the 2nd electroconductive part 23, the some core substance 24, and the insulating substance 25. The first conductive parts 22 are arranged on the surfaces of the base material particles 2 . The second conductive portion 23 is disposed on the surface of the first conductive portion 22 . A plurality of core substances 24 are arranged on the surface of the substrate particle 2 . The first conductive portion 22 and the second conductive portion 23 cover the base material particles 2 and the plurality of core substances 24 . The electroconductive particle 21 is a coating particle which coat|covers the surface of the base material particle 2 and the core substance 24 with the 1st electroconductive part 22 and the 2nd electroconductive part 23.

The conductive particle 21 has a plurality of protrusions 21a on the outer surface of the conductive portion. The first conductive portion 22 and the second conductive portion 23 have a plurality of protrusions 22a and 23a on the outer surfaces. A plurality of core substances 24 are embedded in the first conductive portion 22 and the second conductive portion 23 . The core substance 24 is arranged inside the protrusions 21a, 22a and 23a. The outer surfaces of the first conductive portion 22 and the second conductive portion 23 are raised by a plurality of core substances 24, and protrusions 21a, 22a, and 23a are formed. In this way, the said electroconductive particle may have a processus|protrusion on the outer surface of an electroconductive part. Moreover, the said electroconductive particle may not have a processus|protrusion on the outer surface of a 1st electroconductive part, and may have a processus|protrusion on the outer surface of a 2nd electroconductive part. The said electroconductive particle may equip the inside or inner side of a 2nd electroconductive part with the some core substance which raised the surface of a 2nd electroconductive part so that a plurality of protrusions may be formed. The core substance may be located inside the first conductive portion, may be located inside the first conductive portion, or may be located outside the first conductive portion.

In the electroconductive particle 21, in order to form protrusions 21a, 22a, and 23a, a plurality of core substances 24 are used. In the said electroconductive particle, in order to form the said processus|protrusion, it is not necessary to use a plurality of said core substances. In the said electroconductive particle, it is not necessary to have a plurality of said core substances.

The electroconductive particle 21 has the insulating substance 25 arrange|positioned on the outer surface of the 2nd electroconductive part 23. At least a partial region of the outer surface of the second conductive portion 23 is covered with an insulating substance 25 . The insulating substance 25 is formed of an insulating material and is an insulating particle. Thus, the said electroconductive particle may have the insulating substance arrange|positioned on the outer surface of an electroconductive part. However, the said electroconductive particle may not necessarily have an insulating substance.

Hereinafter, other details of the electroconductive particles will be described. In addition, in the following description, "(meth)acrylic acid" refers to one or both of "acrylic acid" and "methacrylic acid", and "(meth)acrylate" refers to "acrylate" and "methacrylic acid". methacrylate” one or both.

(Substrate particles) As the above-mentioned substrate particles, resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, metal particles, and the like can be mentioned. The above-mentioned substrate particles are preferably substrate particles other than metal particles, more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles. The said base material particle may be the core-shell particle which has a core and the shell arrange|positioned on the surface of this core.

The above-mentioned base material particles are further preferably resin particles or organic-inorganic hybrid particles, and may be resin particles or organic-inorganic hybrid particles. By using these preferable base material particles, the effect of the present invention can be exerted more effectively, and electroconductive particles more suitable for electrical connection between electrodes can be obtained.

When connecting between electrodes using the said electroconductive particle, after arrange|positioning the said electroconductive particle between electrodes, the said electroconductive particle is compressed by crimping. When the base material particle is a resin particle or an organic-inorganic hybrid particle, the said electroconductive particle will deform|transform easily at the time of the said pressure-bonding, and the contact area of an electroconductive particle and an electrode will become large. Therefore, the conduction reliability between electrodes is further improved.

As the material of the above-mentioned resin particles, various resins can be preferably used. Examples of the material of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; polymethyl methacrylate, Acrylic resins such as polymethyl acrylate; polyalkylene 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, polysiloxane, polyphenylene ether, polyacetal, polyimide, polyamide imide, polyether Ether ketones, polyether ketones, and polymers obtained by polymerizing one or more of various polymerizable monomers having ethylenically unsaturated groups, etc.

Since it is possible to design and synthesize any resin particles having physical properties during compression suitable for conductive materials, and the hardness of the substrate particles can be easily controlled to a preferred range, the material of the above resin particles is preferably made of vinyl. A polymer obtained by polymerizing one or two or more types of unsaturated polymerizable monomers.

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

Examples of the non-crosslinkable monomers include styrene-based monomers such as styrene and α-methylstyrene; and carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride. body; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate Alkyl (meth)acrylate compounds such as lauryl acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and iso(meth)acrylate; (Meth)acrylate compounds containing oxygen atoms such as 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate; Nitrile-containing monomers such as (meth)acrylonitrile; acid vinyl ester compounds such as vinyl acetate, vinyl butyrate, vinyl laurate, and vinyl stearate; unsaturated such as ethylene, propylene, isobutylene, butadiene, etc. Hydrocarbon; trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, chlorostyrene and other halogen-containing monomers, etc.

As said crosslinkable monomer, tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, for example , Trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate ester, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)1,4-butanediol di(meth)acrylate, 1,4- Polyfunctional (meth)acrylate compounds such as butanediol di(meth)acrylate; (iso)triallyl cyanurate, triallyl trimellitate, divinylbenzene, diphthalate Allyl ester, diallyl acrylamide, diallyl ether, γ-(meth)acryloyloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, etc. Silane monomer, etc.

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

When the above-mentioned base material particles are inorganic particles other than metal particles or organic-inorganic hybrid particles, the inorganic substances used as the material of the above-mentioned base material particles include silica, alumina, barium titanate, zirconia, and carbon. black etc. It is preferable that the said inorganic substance is not a metal. It does not specifically limit as particle|grains formed by the said silica, For example, by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, forming cross-linked polymer particles and then calcining as necessary obtained particles. As said organic-inorganic hybrid particle, the organic-inorganic hybrid particle etc. which are formed by the crosslinked alkoxysilyl polymer and acrylic resin are mentioned, for example.

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

As a material of the said organic core, the material of the said resin particle etc. are mentioned.

As a material of the said inorganic shell, the inorganic substance mentioned as a material of the said base material particle is mentioned. The material of the above-mentioned inorganic shell is preferably silicon dioxide. The inorganic shell is preferably formed by forming a metal alkoxide into a shell on the surface of the core by a sol-gel method, and then calcining the shell. The above-mentioned metal alkoxide is preferably a silane alkoxide. The above-mentioned inorganic shell is preferably formed by a silane alkoxide.

When the said base material particle is a metal particle, silver, copper, nickel, silicon, gold, titanium, etc. are mentioned about the metal which is the material of this metal particle. However, it is preferable that the said base material particle is not a metal particle.

The particle size of the substrate particles is preferably 1 μm or more, more preferably 2 μm or more, further preferably more than 2.5 μm, particularly preferably 3 μm or more, and preferably 1000 μm or less, more preferably 100 μm or less , more preferably 30 μm or less, particularly preferably 5 μm or less. When the particle diameter of the said base material particle is more than the said lower limit or exceeds the said lower limit, since the contact area of the electroconductive particle and the electrode becomes large, the conduction reliability between electrodes becomes further high, and the connection via electroconductive particle can be reduced more effectively The connection resistance between the electrodes. Furthermore, when forming a conductive part on the surface of a base material particle, it is difficult to aggregate, and it becomes difficult to form aggregated electroconductive particle. When the particle diameter of the said base material particle is below the said upper limit, electroconductive particle becomes easy to fully compress, and the connection resistance between electrodes connected via electroconductive particle can be reduced more effectively. Moreover, even if the space|interval between electrodes becomes small and the thickness of an electroconductive part becomes thick, small electroconductive particle can be obtained.

The particle diameter of the above-mentioned substrate particles indicates the diameter when the substrate particles are true spherical, and represents the maximum diameter when the substrate particles are not true spherical.

The particle diameter of the above-mentioned base material particle represents the number average particle diameter. The particle diameter of the said base material particle is calculated|required using a particle size distribution measuring apparatus etc.. The particle diameter of the base material particles is preferably determined by observing 50 arbitrary base material particles with an electron microscope or an optical microscope and calculating an average value. In electroconductive particle, when measuring the particle diameter of the said base material particle, it can measure as follows, for example.

The conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. in a content of 30% by weight, and were dispersed to prepare an embedded resin for conductive particle inspection. A cross section of the conductive particles was cut out using an ion mill (“IM4000” manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the conductive particles dispersed in the embedded resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25000 times, 50 electroconductive particles were randomly selected, and the substrate particles of each electroconductive particle were observed. The particle diameter of the base material particle of each electroconductive particle was measured, and these were averaged, and it was set as the particle diameter of the base material particle.

(1st electroconductive part and 2nd electroconductive part) The said electroconductive particle has a 1st electroconductive part. The metal used as the material of the above-mentioned first conductive portion is not particularly limited. Examples of the above-mentioned metals include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon and Such alloys, etc. Moreover, as said metal, a tin-doped indium oxide (ITO), a solder, etc. are mentioned. Only one type of metal may be used as the material of the first conductive portion, or two or more types may be used in combination.

From the viewpoint of more effectively improving conduction reliability between electrodes, the metal used as the material of the first conductive portion is preferably an alloy containing tin, nickel, palladium, copper or gold, more preferably nickel or palladium.

It is preferable that the said 1st electroconductive part contains nickel and phosphorus from a viewpoint of improving the conduction|electrical_connection reliability between electrodes more effectively. It is preferable that the said 1st conductive part is a conductive part containing nickel, and it is preferable that it contains nickel as a main metal. The content of nickel in 100 wt % of the first conductive portion is preferably 10 wt % or more, more preferably 50 wt % or more, further preferably 60 wt % or more, further preferably 70 wt % or more, particularly preferably 90% by weight or more. The content of nickel in 100 wt % of the first conductive portion may be 97 wt % or more, 97.5 wt % or more, or 98 wt % or more. When the content of nickel in the first conductive portion is equal to or more than the lower limit, the conduction reliability between electrodes can be more effectively improved.

The content of phosphorus in 100 wt % of the first conductive portion is preferably 0.1 wt % or more, more preferably 0.5 wt % or more, and preferably 15 wt % or less, more preferably 10 wt % or less. The connection resistance between electrodes becomes low more effectively that content of phosphorus in the said 1st electroconductive part is more than the said minimum and below the said upper limit.

From the viewpoint of more effectively improving the conduction reliability between electrodes, and from the viewpoint of more effectively preventing breakage of the conductive portion due to external impact, it is preferable that the above-mentioned first conductive portion has a thickness in the thickness direction of the above-mentioned first conductive portion. The content of phosphorus on the side of the second conductive portion in the 1 conductive portion is greater than the content of phosphorus on the side of the substrate particle in the first conductive portion.

It is preferable that the content of phosphorus in 100 wt % of the region from the second conductive portion side to 1/2 of the thickness of the inner side (the region with a thickness of 50% on the outer surface side) of the first conductive portion is more than that of the first conductive portion. The content of phosphorus in 100% by weight of the region from the base material particle side to 1/2 of the thickness toward the outside (region of thickness 50% on the inner surface side). By making the content of phosphorus in 100 wt % of the region with a thickness of 50% on the outer surface side more than that in the region with a thickness of 50 % on the inner surface side of 100 wt %, it is possible to more effectively improve the gap between electrodes. Conduction reliability, and can more effectively prevent the breakage of the conductive part due to external impact.

The content of phosphorus in 100% by weight of the region from the second conductive portion side to half of the thickness toward the inner side (the region with a thickness of 50% on the outer surface side) of the first conductive portion is preferably 1% by weight or more, more preferably It is 3% by weight or more, preferably 15% by weight or less, and more preferably 10% by weight or less. When the content of phosphorus in 100% by weight of the region with a thickness of 50% on the outer surface side is more than or equal to the above lower limit and less than or equal to the above upper limit, the conduction reliability between electrodes can be more effectively improved, and an external impact can be more effectively prevented. The resulting rupture of the conductive part.

The content of phosphorus in 100 wt % of the region from the substrate particle side to 1/2 of the thickness toward the outer side (the region with a thickness of 50% on the inner surface side) of the first conductive portion is preferably 0.1 wt % or more, more preferably 0.1 wt % or more. 0.5% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less. When the content of phosphorus in 100% by weight of the region with a thickness of 50% on the inner surface side is not less than the above lower limit and not more than the above upper limit, the conduction reliability between electrodes can be more effectively improved, and an external impact can be prevented more effectively The resulting rupture of the conductive part.

The content of phosphorus can be determined by using a focused ion beam to prepare thin film slices of conductive particles, using a field emission type transmission electron microscope (“JEM-2010FEF” manufactured by JEOL Ltd.), and using an energy dispersive X-ray analyzer (EDS) to measure.

The thickness of the first conductive portion is preferably 100 nm or more, more preferably 150 nm or more, and preferably 300 nm or less, more preferably 250 nm or less. When the thickness of the said 1st electroconductive part is more than the said minimum and below the said upper limit, the connection resistance between electrodes becomes low more effectively. The thickness of the said 1st electroconductive part means the thickness of the part in which the said 1st electroconductive part was formed, and does not include the part which did not form the said 1st electroconductive part. The thickness of the said 1st electroconductive part shows the average thickness of the 1st electroconductive part of electroconductive particle.

The thickness of the said 1st electroconductive part can be measured by observing the cross section of electroconductive particle using a transmission electron microscope (TEM), for example.

The said electroconductive particle has a 2nd electroconductive part. The second conductive portion preferably contains gold, silver, palladium, platinum, copper, cobalt, ruthenium, indium, or tin, more preferably gold or silver, and still more preferably gold.

Examples of metals that can be used for the second conductive portion include gold, silver, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, palladium, chromium, titanium, antimony, bismuth, thallium, Germanium, cadmium, silicon, tungsten, molybdenum and tin-doped indium oxide (ITO), etc. Only one type of these metals may be used, or two or more types may be used in combination.

The second conductive portion is preferably a conductive portion containing gold, and preferably contains gold as a main metal. The content of gold in 100 wt % of the second conductive portion is preferably 10 wt % or more, more preferably 50 wt % or more, further preferably 60 wt % or more, further preferably 70 wt % or more, particularly preferably 90% by weight or more. The content of gold in 100 wt % of the second conductive portion may be 97 wt % or more, 97.5 wt % or more, or 98 wt % or more. If the content of gold in the second conductive portion is equal to or greater than the lower limit, the connection resistance between electrodes can be reduced more effectively.

The ionization tendency of the metal contained in the above-mentioned first conductive portion is preferable from the viewpoint of more effective improvement of conduction reliability between electrodes and from the viewpoint of more effective prevention of breakage of the conductive portion due to external impact It is larger than the ionization tendency of the metal contained in the said 2nd electroconductive part.

The thickness of the second conductive portion is preferably 20 nm or more, more preferably 25 nm or more, and preferably 40 nm or less, more preferably 35 nm or less. The connection resistance between electrodes becomes low more effectively that the thickness of the said 2nd electroconductive part is more than the said minimum and below the said upper limit. The thickness of the second conductive portion refers to the thickness of the portion where the second conductive portion is formed, and does not include the portion where the second conductive portion is not formed. The thickness of the said 2nd electroconductive part shows the average thickness of the 2nd electroconductive part of electroconductive particle.

The thickness of the said 2nd electroconductive part can be measured by observing the cross section of electroconductive particle using a transmission electron microscope (TEM), for example.

The method of forming the said 1st conductive part and the said 2nd conductive part is not specifically limited. Examples of methods for forming the first conductive portion and the second conductive portion include a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and bonding of metal powder or containing metal powder to The method of coating the slurry of the agent on the surface of the substrate particles, etc. Since the formation of the conductive portion is relatively simple, it is preferable to use the method of electroless plating. As a method by the above-mentioned physical vapor deposition, methods, such as vacuum vapor deposition, ion plating, and ion sputtering, are mentioned.

As a method of controlling the content of nickel and phosphorus in the above-mentioned first conductive portion, the following methods and the like are exemplified. A method of controlling the pH of a nickel plating solution when the first conductive portion is formed by electroless nickel plating. A method of adjusting the concentration of a phosphorus-containing reducing agent when the first conductive portion is formed by electroless nickel plating. A method for adjusting the nickel concentration in a nickel plating solution.

The manufacturing method of the said electroconductive particle comprises the process of using the electroconductive particle provided with the base material particle and the 1st electroconductive part arrange|positioned on the surface of the said base material particle, and performing a plating process on the outer surface of the said 1st electroconductive part The second conductive portion is disposed on the top. By this process, the electroconductive particle provided with the said 2nd electroconductive part on the outer surface of the said 1st electroconductive part can be obtained.

When forming the first conductive portion, it is preferable that the content of phosphorus on the side of the second conductive portion in the first conductive portion is higher than that in the first conductive portion in the thickness direction of the first conductive portion. Phosphorus content on the particle side of the substrate. By forming the above-mentioned first conductive portion using the above-described preferred aspect, the conduction reliability between electrodes can be more effectively improved, and the breakage of the conductive portion due to external impact can be more effectively prevented. In the thickness direction of the first conductive portion, the content of phosphorus on the side of the second conductive portion in the first conductive portion is greater than the content of phosphorus on the side of the base material particle in the first conductive portion, thereby Elution of the metal (for example, nickel etc.) which is the material of the said 1st electroconductive part can be suppressed. As a result, the generation of pinholes in the first conductive portion can be more effectively suppressed, and the breakage of the conductive portion due to external impact can be more effectively prevented.

From the viewpoint of more effectively improving the conduction reliability between electrodes, and from the viewpoint of more effectively preventing breakage of the conductive portion due to external impact, in the plating treatment for forming the second conductive portion, it is preferable to Use both replacement gold plating and reduction gold plating. When forming the said 2nd electroconductive part, the elution of the metal (for example, nickel etc.) which is a material of the said 1st electroconductive part can be suppressed by using both substitution gold plating and reduction gold plating. As a result, the generation of pinholes in the first conductive portion can be more effectively suppressed, and the breakage of the conductive portion due to external impact can be more effectively prevented.

Moreover, as another method of suppressing the elution of the metal (for example, nickel etc.) which is the material of the said 1st conductive part, the method of performing nickel plating in advance before performing the plating process which forms the said 2nd conductive part is mentioned. By performing nickel plating in advance, the nickel for elution eluted by the plating treatment (substitution gold plating and reduction gold plating) for forming the second conductive portion can be preliminarily disposed on the surface of the first conductive portion. In the plating treatment (substitution gold plating and reduction gold plating) for forming the second conductive portion, the elution of the metal (eg, nickel, etc.) which is the material of the first conductive portion can be suppressed by elution of nickel for elution. As a result, the generation of pinholes in the first conductive portion can be more effectively suppressed, and the breakage of the conductive portion due to external impact can be more effectively prevented.

It is preferable that the manufacturing method of the said electroconductive particle combines the said method from a viewpoint of improving the conduction reliability between electrodes more effectively, and a viewpoint of preventing the breakage of the electroconductive part by external impact more effectively. Specifically, it is preferable to combine the following (1st structure), (2nd structure), and (3rd structure). (1st structure) The manufacturing method of the said electroconductive particle makes the content of phosphorus on the side of the said 2nd electroconductive part in the said 1st electroconductive part more than in the said 1st electroconductive part in the thickness direction of the said 1st electroconductive part The phosphorus content on the particle side of the above-mentioned substrate. (Second configuration) The plating treatment for forming the second conductive portion is a combination of substitution gold plating and reduction gold plating. (3rd structure) Nickel plating is performed in advance before performing the plating process which forms the said 2nd electroconductive part. By combining all the above-mentioned structures, the above-mentioned second conductive portion can be formed as follows: when the outer surface of the above-mentioned second conductive portion is observed with an electron microscope, there is no pinhole with a size of 50 nm or more in the maximum longitudinal direction. , or there are pinholes with a size of 50 nm or more in the maximum length direction at 1/μm ² or less.

(Core substance) It is preferable that the said electroconductive particle has a some processus|protrusion on the outer surface of the said 1st electroconductive part and the said 2nd electroconductive part. By having the said electroconductive particle in the outer surface of the said 1st electroconductive part and the said 2nd electroconductive part several protrusions, the conduction|electrical_connection reliability between electrodes can be improved further. In many cases, an oxide film is formed on the surface of the electrode connected by the said electroconductive particle. Furthermore, an oxide film is formed in the surface of the said 1st electroconductive part of the said electroconductive particle and the said 2nd electroconductive part in many cases. By using the electroconductive particle which has the said protrusion, after arrange|positioning electroconductive particle between electrodes, it can remove|eliminate an oxide film efficiently by a protrusion and press-bond. Therefore, the electrode and the electroconductive particle can be brought into contact with each other more reliably, and the connection resistance between the electrodes can be lowered more effectively. Furthermore, when the conductive particles have an insulating substance on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the conductive particles and the electrodes are formed by the protrusions of the conductive particles. The resin in between is effectively excluded. Therefore, the conduction reliability between electrodes can be improved more effectively.

By embedding the core material in the first conductive portion and the second conductive portion, a plurality of protrusions can be easily formed on the outer surfaces of the first conductive portion and the second conductive portion. However, in order to form a protrusion on the surface of the said 1st electroconductive part and the said 2nd electroconductive part, it is not necessary to use a core substance.

As a method of forming the above-mentioned protrusions, after attaching the core material to the surface of the base material particles, a method of forming the first conductive portion and the second conductive portion by electroless plating, and electroless plating on the After forming a 1st conductive part on the surface of a base material particle, the method of attaching a core substance, and forming a 2nd conductive part by electroless plating, etc., is performed. Other methods of forming the protrusions include: after forming the first conductive portion on the surface of the substrate particle, disposing a core material on the first conductive portion, and then forming the second conductive portion; In the middle stage of forming the conductive portion (first conductive portion or second conductive portion, etc.) on the surface of the material particle, the method of adding the core substance, etc. In addition, in order to form the protrusions, a method of forming protrusions on the surface of the first conductive parts after forming the first conductive parts on the substrate particles by electroless plating without using the above-mentioned core material may also be used. form precipitation, and further the second conductive portion is formed by electroless plating.

As a method of disposing the core material on the outer surface of the base material particles, for example, adding the core material to the dispersion liquid of the base material particles, and using Van der Waals force or the like to make the core material aggregate and adhere to the surface of the base material particles can be mentioned. The method of adding the core material to the container in which the base material particles are added, and the method of attaching the core material to the surface of the base material particle by using the mechanical action generated by the rotation of the container, etc. The method of agglomerating and adhering the core substance to the surfaces of the substrate particles in the dispersion liquid is preferable because it is easy to control the amount of the adhering core substance.

The material of the above-mentioned core substance is not particularly limited. As a material of the said core substance, a conductive substance and a non-conductive substance are mentioned, for example. As said electroconductive substance, metal, metal oxide, electroconductive nonmetals, such as zinc, electroconductive polymer, etc. are mentioned. As said conductive polymer, polyacetylene etc. are mentioned. As said non-conductive substance, silica, alumina, barium titanate, zirconia, etc. are mentioned. The above-mentioned core material is preferably a metal because the electrical conductivity can be improved and the connection resistance can be effectively reduced. The above-mentioned core substance is preferably metal particles. As the metal used as the material of the above-mentioned core material, the metals listed as the material of the above-mentioned conductive material can be appropriately used.

The Mohs hardness of the material of the above-mentioned core substance is preferably higher. As materials with higher Mohs hardness, barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silicon dioxide (silicon dioxide, Mohs hardness 6~7), titanium oxide (Mohs hardness 6~7), hardness 7), zirconia (Mohs hardness 8~9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9) and diamond (Mohs hardness 10), etc. The above-mentioned core material is preferably nickel, silicon dioxide, titanium oxide, zirconium oxide, aluminum oxide, tungsten carbide or diamond, more preferably silicon dioxide, titanium oxide, zirconium oxide, aluminum oxide, tungsten carbide or diamond. The above-mentioned core material is further preferably titanium oxide, zirconium oxide, aluminum oxide, tungsten carbide or diamond, particularly preferably zirconium oxide, aluminum oxide, tungsten carbide or diamond. The Mohs hardness of the material of the core material is preferably 4 or more, more preferably 5 or more, still more preferably 6 or more, still more preferably 7 or more, particularly preferably 7.5 or more.

The shape of the above-mentioned core material is not particularly limited. The shape of the core material is preferably block-like. Examples of the core material include granular agglomerates, agglomerates formed by agglomerating a plurality of fine particles, and indeterminate agglomerates.

The particle size of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the particle diameter of the said core substance is more than the said minimum and below the said upper limit, the connection resistance between electrodes becomes low effectively.

The particle diameter of the above-mentioned core material represents the number average particle diameter. The particle diameter of the core material is preferably determined by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

The number of the said protrusion per 1 of the said electroconductive particle becomes like this. Preferably it is 3 or more, More preferably, it is 5 or more. The upper limit of the number of the protrusions is not particularly limited. The upper limit of the number of the above-mentioned protrusions can be appropriately selected in consideration of the particle diameter of the electroconductive particles, the use of the electroconductive particles, and the like.

It is preferable that the number of the said protrusion per 1 of the said electroconductive particle is calculated|required by observing 50 arbitrary electroconductive particles with an electron microscope or an optical microscope, and calculating an average value.

The height of the plurality of protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the height of the said protrusion is more than the said minimum and below the said upper limit, the connection resistance between electrodes becomes low effectively.

It is preferable that the height of a plurality of said protrusions is calculated|required by observing 50 arbitrary electroconductive particles with an electron microscope or an optical microscope, and calculating an average value.

(Insulating substance) It is preferable that the said electroconductive particle is provided with the insulating substance arrange|positioned on the surface of the said electroconductive part. In this case, if the said electroconductive particle is used for the connection between electrodes, the short circuit between adjacent electrodes can be prevented further. Specifically, when a plurality of electroconductive particles are in contact, since an insulating substance exists between a plurality of electrodes, it is possible to prevent short circuits between electrodes adjacent in the lateral direction rather than short circuits between upper and lower electrodes. Furthermore, at the time of connection between electrodes, by pressurizing electroconductive particle with two electrodes, the insulating substance between the electroconductive part of electroconductive particle and an electrode can be removed easily. When the said electroconductive particle has a plurality of protrusions on the outer surface of an electroconductive part, the insulating substance between the electroconductive part of an electroconductive particle and an electrode can be removed more easily.

It is preferable that the said insulating material is an insulating particle because the said insulating material can be removed more easily at the time of crimping|bonding between electrodes.

As a material of the said insulating substance, the material of the said resin particle, and the inorganic substance mentioned as a material of the said base material particle, etc. are mentioned. It is preferable that the material of the said insulating substance is the material of the said resin particle. It is preferable that the said insulating substance is the said resin particle or the said organic-inorganic hybrid particle, and resin particle may be sufficient as it, and an organic-inorganic hybrid particle may be sufficient as it.

As other materials of the above-mentioned insulating substances, polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, cross-linked products of thermoplastic resins, thermal Curable resin and water-soluble resin, etc. As for the material of the said insulating substance, only 1 type may be used, and 2 or more types may be used together.

As said polyolefin compound, polyethylene, an ethylene-vinyl acetate copolymer, an ethylene-acrylate copolymer, etc. are mentioned. As said (meth)acrylate polymer, a polymethyl (meth)acrylate, a poly (meth)acrylate lauryl, a poly (meth)acrylate, etc. are mentioned. Examples of the above-mentioned block polymer include polystyrene, styrene-acrylate copolymer, SB (styrene-butadiene) type styrene-butadiene block copolymer, and SBS (styrene-butadiene). -butadiene-styrene, styrene-butadiene-styrene) type styrene-butadiene block copolymer, and their hydrides, etc. As said thermoplastic resin, a vinyl polymer, a vinyl copolymer, etc. are mentioned. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the cross-linked product of the thermoplastic resin include introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, or alkoxylated pentaerythritol methacrylate. As said water-soluble resin, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, methyl cellulose, etc. are mentioned. Moreover, a chain transfer agent can also be used for adjustment of a polymerization degree. As a chain transfer agent, a mercaptan, carbon tetrachloride, etc. are mentioned.

A chemical method, a physical or mechanical method, etc. are mentioned as a method of disposing an insulating substance on the surface of the said electroconductive part (2nd electroconductive part). As said chemical method, the interfacial polymerization method, the suspension polymerization method in the presence of particles, the emulsion polymerization method, etc. are mentioned, for example. As said physical or mechanical method, the method by spray drying, mixing, electrostatic adsorption method, spray method, immersion, and vacuum vapor deposition, etc. are mentioned. From the viewpoint that the insulating substance is not easily detached, a method of disposing the insulating substance on the surface of the second conductive portion through chemical bonding is preferable.

The outer surface of the said conductive part (2nd conductive part) and the surface of an insulating material may be respectively coat|covered with the compound which has a reactive functional group. The outer surface of the conductive portion (second conductive portion) and the surface of the insulating material may be chemically bonded directly, or may be chemically bonded indirectly through a compound having a reactive functional group. After the carboxyl group is introduced into the outer surface of the conductive part (second conductive part), the carboxyl group may be chemically bonded to the functional group on the surface of the insulating material via a polymer electrolyte such as polyethyleneimine.

The particle diameter of the said insulating material can be suitably selected according to the particle diameter of an electroconductive particle, the use of an electroconductive particle, etc.. The particle size of the insulating material is preferably 10 nm or more, more preferably 100 nm or more, and preferably 4000 nm or less, more preferably 2000 nm or less. When the particle diameter of an insulating substance is more than the said minimum, when electroconductive particle is disperse|distributed to binder resin, the electroconductive part in a some electroconductive particle will become hard to contact mutually. When the particle diameter of the insulating substance is below the above upper limit, in order to remove the insulating substance between the electrodes and the conductive particles during connection between electrodes, it is not necessary to increase the pressure and to heat to a high temperature.

The particle diameter of the above-mentioned insulating material represents the number average particle diameter. The particle size of the insulating substance is determined using a particle size distribution analyzer or the like. The particle diameter of the insulating material is preferably determined by observing 50 arbitrary insulating materials with an electron microscope or an optical microscope and calculating an average value. In electroconductive particle, when measuring the particle diameter of an insulating substance, it can measure by the following method, for example.

The conductive particles were added to "Technovit 4000" manufactured by Kulzer Co., Ltd. in a content of 30% by weight, and were dispersed to prepare an embedded resin for conductive particle inspection. A cross section of the conductive particles was cut out using an ion mill (“IM4000” manufactured by Hitachi High-Technology Co., Ltd.) so as to pass through the vicinity of the center of the conductive particles dispersed in the embedded resin for inspection. Next, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 50,000 times, and 50 electroconductive particles were randomly selected, and the insulating substance of each electroconductive particle was observed. The particle diameter of the insulating substance in each electroconductive particle was measured, and the particle diameter of the insulating substance was obtained by arithmetically averaging the particle diameter.

(Conductive material) The conductive material of this invention contains the said electroconductive particle and a binder resin. It is preferable to disperse|distribute the said electroconductive particle in a binder resin, and it is preferable to use it as a conductive material. The above-mentioned conductive material is preferably an anisotropic conductive material. The above-mentioned conductive materials are preferably used for electrical connection between electrodes. The above-mentioned conductive material is preferably a conductive material for circuit connection.

The above-mentioned binder resin is not particularly limited. As said binder resin, a well-known insulating resin is used. It is preferable that the said binder resin contains a thermoplastic component (thermoplastic compound) or a sclerosing|hardenable component, More preferably, it contains a sclerosing|hardenable component. As said curable component, a photocurable component and a thermosetting component are mentioned. It is preferable that the said photocurable component contains a photocurable compound and a photopolymerization initiator. It is preferable that the said thermosetting component contains a thermosetting compound and a thermosetting agent.

As said binder resin, a vinyl resin, a thermoplastic resin, a curable resin, a thermoplastic block copolymer, an elastomer, etc. are mentioned, for example. Only one type of the above-mentioned binder resin may be used, or two or more types may be used in combination.

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

In addition to the above-mentioned conductive particles and the above-mentioned binder resin, the above-mentioned conductive material may also include, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a hardening catalyst, a colorant, an antioxidant, a thermal stabilizer additives, light stabilizers, UV absorbers, lubricants, antistatic agents and flame retardants.

From the viewpoint of more effectively reducing the connection resistance between the electrodes and more effectively improving the conduction reliability between the electrodes, the viscosity (η25) at 25°C of the above-mentioned conductive material is preferably 20 Pa·s or more, More preferably, it is 30 Pa·s or more, more preferably 400 Pa·s or less, and more preferably 300 Pa·s or less. The above-mentioned viscosity (η25) can be appropriately adjusted by the types and amounts of the ingredients to be prepared.

The said viscosity can be measured under the conditions of 25 degreeC and 5 rpm using, for example, an E-type viscometer ("TVE22L" by Toki Sangyo Co., Ltd.).

The above-mentioned conductive materials can be used as conductive pastes, conductive films, and the like. When the said conductive material is a conductive film, the film which does not contain electroconductive particle may be laminated|stacked on the electroconductive particle containing electroconductive film. The above-mentioned conductive paste is preferably anisotropic conductive paste. The above-mentioned 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, more preferably 50% by weight or more, particularly preferably 70% by weight or more, and more preferably Preferably it is 99.99 weight% or less, More preferably, it is 99.9 weight% or less. When content of the said binder resin is more than the said minimum and below the said upper limit, electroconductive particle is efficiently arrange|positioned between electrodes, and the connection reliability of the connection object member connected by a conductive material improves further.

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, and preferably 80% by weight or less, more preferably 60% by weight or less, and more preferably It is preferably 40% by weight or less, more preferably 20% by weight or less, and most preferably 10% by weight or less. The conduction reliability between electrodes will further improve that content of the said electroconductive particle is more than the said minimum and below the said upper limit.

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

The connection structure preferably includes a first connection target member, a second connection target member, and a connection portion connecting the first connection target member and the second connection target member, and the material of the connection portion is the conductive particles, Or a conductive material containing the above-mentioned conductive particles and a binder resin. It is preferable that the said connection part is formed by the said electroconductive particle, or it is formed by the electroconductive material containing the said electroconductive particle and a binder resin. When using electroconductive particle, the connection part itself is electroconductive particle.

It is preferable that the said 1st connection object member has a 1st electrode on the surface. It is preferable that the said 2nd connection object member has a 2nd electrode on the surface. It is preferable that the said 1st electrode and the said 2nd electrode are electrically connected by the said electroconductive particle.

It is preferable that the said connection structure is equipped with a flexible member as the said 1st connection object member or the said 2nd connection object member. In this case, at least one of the first connection target member and the second connection target member may be a flexible member, and both the first connection target member and the second connection target member may be flexible. flexible member. It is preferable to use the above-mentioned connecting structure in a state where the above-mentioned flexible member is bent. It is preferable to use the said connection structure in the state which the said connection part was bent.

It is sectional drawing which shows typically the connection structure which used the electroconductive particle of 1st Embodiment of this invention.

The connection structure 51 shown in FIG. 3 includes a first connection target member 52 , a second connection target member 53 , and a connection portion 54 that connects the first connection target member 52 and the second connection target member 53 . The connection portion 54 is formed of a conductive material containing the conductive particles 1 . It is preferable that the said conductive material has thermosetting property, and the connection part 54 is formed by thermosetting the conductive material. In addition, in FIG. 3, for convenience of illustration, the electroconductive particle 1 is shown simply. Instead of the electroconductive particle 1, the electroconductive particle 21 etc. can also be used.

The 1st connection object member 52 has the some 1st electrode 52a on the surface (upper surface). The second connection object member 53 has a plurality of second electrodes 53a on the surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected by one or a plurality of conductive particles 1 . Therefore, the 1st connection object member 52 and the 2nd connection object member 53 are electrically connected by the electroconductive particle 1.

The manufacturing method of the said connection structure is not specifically limited. As an example of the manufacturing method of a connection structure, after arrange|positioning the said conductive material between a 1st connection object member and a 2nd connection object member, and obtaining a laminated body, the method of heating and pressurizing this laminated body, etc. are mentioned. The pressure of the above-mentioned thermocompression bonding is about 0.5×10 ⁶ Pa to 5×10 ⁶ Pa relative to the area to be crimped. The heating temperature of the above thermocompression bonding is about 70°C to 230°C. The heating temperature of the thermocompression bonding is preferably 80°C or higher, more preferably 100°C or higher, and preferably 200°C or lower, more preferably 150°C or lower. The pressure of the thermocompression bonding is preferably 0.5×10 ⁶ Pa or higher, more preferably 1×10 ⁶ Pa or higher, and preferably 5×10 ⁶ Pa or lower, more preferably 3×10 ⁶ Pa or lower. The conduction reliability between electrodes can be improved more effectively as the pressure and temperature of the said thermocompression bonding are more than the said lower limit and below the said upper limit.

Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components such as printed circuit boards, flexible printed circuit boards, glass epoxy substrates, and circuit boards such as glass substrates. It is preferable that the said connection object member is an electronic component. It is preferable that the said electroconductive particle is used for the electrical connection of the electrode of an electronic component.

Metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, silver electrodes, SUS electrodes, copper electrodes, molybdenum electrodes, and tungsten electrodes are exemplified as the electrodes provided on the connection target member. When the connection object member is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode or a copper electrode. When the said connection object member is a glass substrate, the said electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode or a tungsten electrode. Furthermore, when the above-mentioned electrode is an aluminum electrode, it may be an electrode formed only by aluminum, or an electrode having an aluminum layer on the surface layer of the metal oxide layer may be used. As a material of the said metal oxide layer, the indium oxide doped with a trivalent metal element, the zinc oxide doped with a trivalent metal element, etc. are mentioned. As said trivalent metal element, Sn, Al, Ga, etc. are mentioned.

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

Substrate particles: Substrate particles A: resin particles, copolymer resin particles of divinylbenzene and iso-acrylate, particle size: 10 μm Substrate particles B: resin particles, divinylbenzene and iso-acrylate Copolymer resin particles, particle size: 5 μm Substrate particle C: resin particles, copolymer resin particles of divinylbenzene and iso-acrylate, particle size: 20 μm

(Example 1) (1) The first conductive part (nickel layer) was formed by dispersing 10 parts by weight of the substrate particles A in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser After the medium, the substrate particles A were taken out by filtering the solution. Next, the substrate particles A were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surfaces of the substrate particles A. After the surface-activated base material particle A was sufficiently washed with water, it was added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

Furthermore, a nickel plating solution (pH 9.0) containing 0.25 mol/L of nickel sulfate, 0.25 mol/L of sodium hypophosphite, and 0.15 mol/L of sodium citrate was prepared.

While stirring the obtained suspension at 70° C., the above-mentioned nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Then, the particles were taken out by filtering the suspension, washed with water, and dried to obtain particles with the first conductive portion (nickel-phosphorus layer, thickness 200 nm) disposed on the surface of the substrate particles A. The content of nickel in 100% by weight of the conductive layer was 94.5% by weight, and the content of phosphorus was 5.5% by weight.

(2) Formation of the second conductive part (gold layer) A suspension was obtained by adding 10 parts by weight of the particles having the first conductive part arranged on the surface of the substrate particle A to 100 parts by weight of distilled water and dispersing it. Furthermore, a reduction gold plating solution containing 0.03 mol/L of gold cyanide and 0.1 mol/L of hydroquinone as a reducing agent was prepared. While stirring the obtained suspension at 70°C, the above-mentioned reduction gold plating solution was gradually added dropwise to the suspension to perform reduction gold plating. After that, the particles are taken out by filtering the suspension, washed with water, and dried to obtain conductive particles. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 31 nm) was arrange|positioned on the outer surface of the said 1st electroconductive part. In FIG. 4, the image of the surface of the electroconductive particle produced in Example 1 is shown.

(Example 2) (1) The first conductive portion (nickel layer) was formed by dispersing 10 parts by weight of the base material particles B in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser After the medium, the substrate particles B are taken out by filtering the solution. Next, the substrate particles B were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surfaces of the substrate particles B. After the surface-activated base material particles B were sufficiently washed with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a suspension.

Furthermore, a nickel plating solution (pH 9.0) containing 0.25 mol/L of nickel sulfate, 0.25 mol/L of sodium hypophosphite, and 0.15 mol/L of sodium citrate was prepared.

While stirring the obtained suspension at 70° C., the above-mentioned nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Then, the particles were taken out by filtering the suspension, washed with water, and dried to obtain particles in which the first conductive portion (nickel-phosphorus layer, thickness 210 nm) was arranged on the surface of the substrate particles B. The content of nickel in 100% by weight of the conductive layer was 94.5% by weight, and the content of phosphorus was 5.5% by weight.

(2) Formation of nickel-plated layer A suspension was obtained by adding 10 parts by weight of the particles having the first conductive portion arranged on the surface of the substrate particle B to 100 parts by weight of distilled water and dispersing it. Furthermore, 52 mL of a nickel solution containing 10% by weight of nickel sulfate, 10% by weight of sodium hypophosphite, 4% by weight of sodium hydroxide, and 20% by weight of sodium succinate was prepared. While stirring the obtained suspension at 80° C., the nickel solution was continuously added dropwise at 5 mL/min and stirred for 20 minutes, whereby a plating reaction was performed. It was confirmed that hydrogen was no longer generated, and the plating reaction was completed. Then, the particle|grains in which the 1st conductive part and the nickel-plating layer were arrange|positioned on the surface of the base material particle B were obtained by filtering out the particle|grains by filtration of the suspension, washing with water, and drying.

(3) Formation of the second conductive part (gold layer) by adding 10 parts by weight of the particles having the first conductive part and the nickel plating layer arranged on the surface of the substrate particle B to 100 parts by weight of distilled water and dispersing it. Obtain a suspension. Furthermore, a reduction gold plating solution containing 0.03 mol/L of gold cyanide and 0.1 mol/L of hydroquinone as a reducing agent was prepared. While stirring the obtained suspension at 70°C, the above-mentioned reduction gold plating solution was gradually added dropwise to the suspension to perform reduction gold plating. After that, the particles are taken out by filtering the suspension, washed with water, and dried to obtain conductive particles. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 30 nm) was arrange|positioned on the outer surface of the said 1st electroconductive part.

(Example 3) The same procedure as in Example 2 was carried out except that the substrate particles B were changed to the substrate particles C, and the thickness of the second conductive portion was changed to 35 nm when the first conductive portion was formed. way to obtain conductive particles. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 35 nm) was arrange|positioned on the outer surface of the 1st electroconductive part.

(Example 4) When forming the first conductive portion, the base material particles B were changed to the base material particles A, and 1 part by weight of metal nickel particles (average particle diameter: 150 nm) was added to the obtained suspension. Conductive particles were obtained in the same manner as in Example 2, except that the suspension of the base material particles A having the core material was changed to 29 nm in thickness of the second conductive portion. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 29 nm) was arrange|positioned on the outer surface of the 1st electroconductive part. The obtained electroconductive particle has a some processus|protrusion on the outer surface of a 1st electroconductive part and a 2nd electroconductive part.

(Example 5) When forming the second conductive portion, the substrate particles B were changed to the substrate particles A, the thickness of the first conductive portion was changed to 230 nm, and the 0.03 mol/L gold cyanide was changed to gold cyanide Conductive particles were obtained in the same manner as in Example 2, except that the thickness of the second conductive portion was changed to 15 nm, 0.015 mol/L. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 15 nm) was arrange|positioned on the outer surface of the 1st electroconductive part.

(Example 6) The conductive parts were obtained in the same manner as in Example 1, except that gold cyanide was changed to palladium sulfate, and the thickness of the second conductive part was changed to 30 nm when forming the second conductive part. Sexual particles. In the obtained electroconductive particle, the 2nd electroconductive part (palladium layer, thickness 30 nm) was arrange|positioned on the outer surface of the 1st electroconductive part.

(Example 7) The same procedure as in Example 2 was carried out except that the substrate particles B were changed to the substrate particles A and the thickness of the second conductive portion was changed to 32 nm when the first conductive portion was formed. way to obtain conductive particles. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 32 nm) was arrange|positioned on the outer surface of the 1st electroconductive part.

(Comparative Example 1) A substitutional gold plating solution containing no hydroquinone as a reducing agent was prepared. When forming the second conductive portion, the second conductive portion was formed by changing the reduction gold plating solution to the replacement gold plating solution, and the replacement gold plating was used instead of the reduction gold plating to form the second conductive portion, and the thickness of the second conductive portion was changed to 32 nm. Conductive particles were obtained in the same manner as in Example 1. In the obtained electroconductive particle, the 2nd electroconductive part (gold layer, thickness 32 nm) was arrange|positioned on the outer surface of the 1st electroconductive part. In addition, the image of the surface of the electroconductive particle produced in the comparative example 1 is shown in FIG.

(Evaluation) (1) Existing state of pinholes The surface of the second conductive portion of the obtained conductive particles was observed with an electron microscope (“FE-SEM SU8010” manufactured by Hitachi High-Technologies Corporation), and the presence or absence of the maximum length was evaluated. The size of the direction is the first pinhole of 50 nm or more. Specifically, the presence or absence of the above-mentioned pinholes was evaluated by observing 5 arbitrary locations with an electron microscope about the portion excluding the portion from the outer periphery to the inner 0.5 μm of the obtained electroconductive particle. When there are first pinholes with a size of 50 nm or more in the maximum longitudinal direction, the number of first pinholes with a size of 50 nm or more in the maximum longitudinal direction per 1 μm ² is measured. Moreover, in the same manner, it was evaluated whether or not there was a second pinhole whose size in the maximum longitudinal direction was 50 nm or more and 200 nm or less. When there is a second pinhole with a size of 50 nm or more and 200 nm or less in the maximum longitudinal direction, measure the number of second pinholes with a size of 50 nm or more and 200 nm or less per 1 μm ² in the maximum longitudinal direction. number.

(2) 10% K value The 10% K value of the obtained electroconductive particles was measured by the above-mentioned method.

(3) Compression recovery rate at 25°C The compression recovery rate at 25°C of the obtained electroconductive particles was measured by the above method.

(4) Average particle size The average particle size of the obtained electroconductive particles was measured using a "laser diffraction particle size distribution analyzer" manufactured by Horiba Manufacturing Co., Ltd. In addition, the average particle diameter of electroconductive particle was computed by averaging the measurement result of 20 times.

(5) Content of phosphorus in the thickness direction of the first conductive portion Using a focused ion beam, thin film slices of the obtained conductive particles were prepared. The content of phosphorus in the thickness direction of the first conductive portion was measured by an energy dispersive X-ray analyzer (EDS) using a field emission transmission electron microscope (“JEM-2010FEF” manufactured by JEOL Ltd.). From this result, the content of phosphorus in 100% by weight of the region from the base material particle side to 1/2 of the thickness toward the outer side (the region with a thickness of 50% on the inner surface side) of the first conductive portion and the first conductive portion were obtained. The content of phosphorus in 100 wt % of the region from the second conductive portion side to 1/2 of the thickness toward the inner side (region of thickness 50% on the outer surface side).

(6) Breakage of the conductive portion Using the obtained conductive particles, the breakage of the conductive portion was evaluated. The rupture of the conductive portion was evaluated in the following manner. Breakage of the conductive portion was determined according to the following criteria.

Evaluation method of the crack of an electroconductive part: Using an electron microscope, the photograph of 1000 electroconductive particles was photographed at a magnification of about 100 electroconductive particles per one photograph. The photograph of the obtained 1000 electroconductive particles was observed, and the number of objects of the electroconductive particle which has the crack which has the length of more than half the diameter of the electroconductive particle was measured.

[Criteria for Determination of Cracked Conductive Part] ○: The number of cracked conductive particles is less than 100 ×: The number of cracked conductive particles is 100 or more

(7) Production of initial connection resistance connection structure X: The obtained conductive particles were added to "Stractbond XN-5A" manufactured by Mitsui Chemicals Co., Ltd. in a content of 10% by weight and dispersed to produce Anisotropic conductive paste.

Prepare a transparent glass substrate with an ITO electrode pattern with L/S of 20 μm/20 μm on the upper surface. Furthermore, a semiconductor wafer having a gold electrode pattern with L/S of 20 μm/20 μm on the lower surface was prepared.

The anisotropic conductive paste immediately after production was applied on the above-mentioned transparent glass substrate so as to have a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the above-mentioned semiconductor wafer is laminated on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 120°C, a pressure heating head is placed on the upper surface of the semiconductor wafer, and a low pressure of 1 MPa calculated from the crimping area is applied. , while the anisotropic conductive paste layer was cured at 100° C. to obtain a connection structure X.

Production of the connection structure Y: The connection structure Y was produced in the same manner as the connection structure X, except that the temperature at the time of curing the anisotropic conductive material layer was changed to 150°C.

Preparation of the connection structure Z: The connection structure Z was produced in the same manner as the connection structure X, except that the temperature at the time of curing the anisotropic conductive material layer was changed to 200°C.

The connection resistance A between the upper and lower electrodes of the obtained connection structures X, Y, and Z was measured by the four-terminal method, respectively. Furthermore, according to the relationship of voltage=current×resistance, the connection resistance A can be obtained by measuring the voltage when a constant current flows. The initial connection resistance was determined from the connection resistance A according to the following criteria.

[Judgment criteria for initial connection resistance] ○○○: Connection resistance A is 2.0 Ω or less ○○: Connection resistance A exceeds 2.0 Ω and 3.0 Ω or less ○: Connection resistance A exceeds 3.0 Ω and is 5.0 Ω or less Δ: Connection Resistance A exceeds 5.0 Ω and is 10 Ω or less ×: Connection resistance A exceeds 10 Ω

(8) Connection resistance after standing at high temperature and high humidity (conduction reliability) The connection structures X, Y, and Z after the above-mentioned (7) initial evaluation of connection resistance were left at 85°C and 85% humidity for 500 hours . In the connection structures X, Y, and Z after being left to stand for 500 hours, the connection resistance B between the upper and lower electrodes was measured by the four-terminal method, respectively. The connection resistance (conduction reliability) after being left to stand at high temperature and high humidity was determined from the connection resistances A and B according to the following criteria.

[Judgment criteria for connection resistance (conduction reliability) after being left at high temperature and high humidity] ○○○: Connection resistance B is less than 1.25 times that of connection resistance A ○○: Connection resistance B is more than 1.25 times that of connection resistance A and does not reach 1.5 times ○: Connection resistance B is 1.5 times or more and less than 2 times of connection resistance A: Connection resistance B is more than 2 times of connection resistance A and less than 5 times ×: Connection resistance B is 5 times of connection resistance A above

The results are shown in Tables 1 and 2 below.

[Table 1]

[Table 2]

1‧‧‧Electrical particle 2‧‧‧Substrate particle 3‧‧‧First conductive part 4‧‧‧Second conductive part 21‧‧‧Conductive particle 21a‧‧‧Protrusion 22‧‧‧First conductive part 22a‧‧‧Projection 23‧‧‧Second conductive portion 23a‧‧‧Protrusion 24‧‧‧Core material 25‧‧‧Insulating material 51‧‧‧Connection structure 52‧‧‧First connection object member 52a‧‧ ‧First electrode 53‧‧‧Second connection target member 53a‧‧‧Second electrode 54‧‧‧connecting part

FIG. 1 is a cross-sectional view showing an electroconductive particle according to a first embodiment of the present invention. It is sectional drawing which shows the electroconductive particle which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows typically the connection structure which used the electroconductive particle of 1st Embodiment of this invention. FIG. 4 is a view showing an image of the surface of the electroconductive particle produced in Example 1. FIG. 5 : is a figure which shows the image of the surface of the electroconductive particle produced in the comparative example 1. FIG.

1‧‧‧Conductive particles

2‧‧‧Substrate particles

3‧‧‧The first conductive part

4‧‧‧Second conductive part

Claims (11)

An electroconductive particle comprising: a base material particle; a first electroconductive portion disposed on the surface of the base material particle; and a second electroconductive portion disposed on the outer surface of the first electroconductive portion; the electroconductivity The particle has a 10% K value at 25°C of 4500 N/ ^mm2 or less, and when the outer surface of the second conductive portion is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or There are pinholes with a size of 50 nm or more in the maximum longitudinal direction at a rate of 1/μm ² or less. An electroconductive particle comprising: a base material particle; a first electroconductive portion disposed on the surface of the base material particle; and a second electroconductive portion disposed on the outer surface of the first electroconductive portion; the electroconductivity The particle has a 10% K value at 25°C of 4500 N/ ^mm2 or less, and when the outer surface of the second conductive portion is observed with an electron microscope, there are no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or There are pinholes whose size in the maximum longitudinal direction is 50 nm or more and 200 nm or less at 1/μm ² or less. The conductive particles of claim 1 or 2 satisfy the relationship of the following formula (1), and the compression recovery rate at 25°C is 10% or less, A≦5500-B×100 formula (1) above formula (1) ), A is the 10% K value (N/mm< ² >) of the said electroconductive particle, and B is the average particle diameter (micrometer) of the said electroconductive particle. The conductive particles according to claim 1 or 2, wherein the conductive particles have an average particle diameter of 3 μm or more and 30 μm or less. The conductive particle according to claim 1 or 2, wherein the second conductive portion contains gold, silver, palladium, platinum, copper, cobalt, ruthenium, indium, or tin. The electroconductive particle of Claim 1 or 2 whose ionization tendency of the metal contained in the said 1st electroconductive part is larger than the ionization tendency of the metal contained in the said 2nd electroconductive part. The electroconductive particle of Claim 1 or 2 whose said 1st electroconductive part contains nickel and phosphorus. The conductive particle according to claim 1 or 2, wherein in the thickness direction of the first conductive portion, the content of phosphorus on the side of the second conductive portion in the first conductive portion is greater than that in the first conductive portion. Phosphorus content on the particle side of the substrate. A method for producing an electroconductive particle, comprising the steps of: using electroconductive particles comprising base material particles and a first electroconductive portion disposed on the surface of the base material particle, and subjecting them to a plating process on the first electroconductive portion. A second conductive part is arranged on the outer surface to obtain conductive particles with a 10% K value at 25°C of 4500 N/mm ² or less; and the second conductive part is formed in the following manner: using an electron microscope on the second conductive part When the outer surface of the part was observed, there were no pinholes with a size of 50 nm or more in the maximum longitudinal direction, or pinholes with a size of 50 nm or more in the maximum longitudinal direction at 1/μm ² or less. A conductive material comprising the conductive particles according to any one of claims 1 to 8 and a binder resin. A connection structure comprising: a first connection target member having a first electrode on a surface; a second connection target member having a second electrode on a surface; and a connection portion connecting the first connection target member with the above-mentioned The second connection object member is connected; the material of the connection part is the conductive particles according to any one of claims 1 to 8, or the conductive material comprising the conductive particles and a binder resin; and the first electrode and the first electrode are Two electrodes are electrically connected by the said electroconductive particle.

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