CN118414371A

CN118414371A - Base material particle, conductive material, and connection structure

Info

Publication number: CN118414371A
Application number: CN202380015189.9A
Authority: CN
Inventors: 安倍大贵; 杉本理; 久永聪
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2022-01-12
Filing date: 2023-01-06
Publication date: 2024-07-30
Also published as: WO2023136204A1; JPWO2023136204A1; KR20240136315A

Abstract

The present invention provides a substrate particle which can reduce the connection resistance of the obtained connection structure and can improve the conduction reliability even under the condition of low-pressure installation. The substrate particles of the present invention are substrate particles comprising a polyorganosiloxane, wherein the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less, and the compression elastic modulus when compressed by 10% at 20 ℃ is 10000N/mm ² or more and 30000N/mm ² or less.

Description

Base material particle, conductive material, and connection structure

Technical Field

The present invention relates to substrate particles comprising polyorganosiloxanes. The present invention also relates to conductive particles, conductive materials, and connection structures using the substrate particles.

Background

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

The anisotropic conductive material is used for electrically connecting electrodes of various connection target components such as Flexible Printed Circuit (FPC), glass substrate, glass epoxy substrate, and semiconductor chip, and thus a connection structure is obtained. As the conductive particles, conductive particles having base particles and a conductive layer disposed on the surface of the base particles may be used. The conductive particles are pressed into the electrodes of the connection target member during mounting, and recesses (indentations) are formed in the surfaces of the electrodes, whereby the electrodes can be electrically connected with each other satisfactorily.

As an example of the base particles used for the conductive particles, patent document 1 below discloses conductive fine particles including resin particles and at least one conductive metal layer formed on the surface of the resin particles. In the conductive fine particles, the number average particle diameter of the resin particles is 8 to 50 μm, and the compressive elastic modulus when the diameter of the resin particles is 10% shifted is 100N/mm ²～3000N/mm². In the conductive fine particles, the value of a-B is 35% or more, where a is the recovery (%) when the resin particles are compressed to a diameter displacement of 10% and B is the recovery (%) when the resin particles are compressed to a diameter displacement of 20%.

Patent document 2 discloses conductive particles in which a conductive layer is formed on the surface of a core particle, wherein the conductive particles have a maximum compression hardness of 24000N/mm ² or more, and have a maximum compression hardness when the compression ratio is less than 5%, and have an average compression hardness of 5000N/mm ²～18000N/mm² when the compression ratio is 20% or more and 50% or less. In the conductive particles, the ratio of the highest value of the compression hardness to the average value of the compression hardness is 1.5 to 10 when the compression ratio is 20 to 50%.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2014-127464

Patent document 2: WO2021/095803A1

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, with the softening of the members to be connected, it has been demanded to perform mounting at a lower pressure in the production of the connection structure.

Since the conductive particles using the base particles described in patent document 1 are soft, it is difficult to sufficiently form recesses (indentations) in the surface of the electrode, and the initial connection resistance of the obtained connection structure may be high and the on-state reliability may be low, particularly when the conductive particles are mounted at low pressure.

In addition, in the conductive particles described in patent document 2, since the entire particles are hard, the conductive particles are difficult to deform, and in particular, when the conductive particles are mounted at a low pressure, the contact area between the conductive particles and the electrode becomes small, and the initial connection resistance of the obtained connection structure may become high, and the on-state reliability may become low.

The purpose of the present invention is to provide a substrate particle that can reduce the connection resistance of the resulting connection structure and can improve the conduction reliability even when the substrate particle is mounted at a low pressure. The present invention also provides conductive particles, conductive materials, and connection structures using the substrate particles.

Means for solving the technical problems

According to a broad aspect of the present invention, there is provided a substrate particle comprising a polyorganosiloxane, wherein the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less, and the substrate particle has a compression elastic modulus of 10000N/mm ² or more and 30000N/mm ² or less when compressed by 10% at 20 ℃.

In a specific aspect of the substrate particle of the present invention, the ratio of the load value at 30% compression at 20 ℃ to the load value at 10% compression at 20 ℃ is 4.0 or less, and the fracture strain is 10% or more and 40% or less.

In a specific aspect of the substrate particle of the present invention, the ratio of the absolute value of the difference between the compression elastic modulus at 20 ℃ and the compression elastic modulus at 20% at 20 ℃ to the absolute value of the difference between the compression elastic modulus at 20% at 20 ℃ and the compression elastic modulus at 30% at 20 ℃ is 1.0 or more.

In a specific aspect of the substrate particle of the present invention, the ratio of the absolute value of the difference between the compression elastic modulus at 20 ℃ and the compression elastic modulus at 20% at 20 ℃ to the absolute value of the difference between the compression elastic modulus at 20% at 20 ℃ and the compression elastic modulus at 30% at 20 ℃ is 1.0 or more and 10.0 or less.

In a specific aspect of the substrate particle of the present invention, the substrate particle has a ratio of the compressive elastic modulus at 150 ℃ compressed by 20% to the compressive elastic modulus at 20 ℃ compressed by 20% of 0.40 or more.

In a specific aspect of the base material particles of the present invention, the base material particles have a compression recovery rate of 60% or more when compressed at 20 ℃, and the base material particles have a ratio of the compression recovery rate of 20% when compressed at 150 ℃ to the compression recovery rate of 20% when compressed at 20 ℃ of 0.30 to 0.90.

In a specific aspect of the substrate particles of the present invention, the particle diameter is 1.0 μm or more and 5.0 μm or less.

In a specific aspect of the substrate particles of the present invention, the polyorganosiloxane material includes a first alkoxysilane having a polymerizable unsaturated group and a second alkoxysilane having no polymerizable unsaturated group.

In a specific aspect of the substrate particle of the present invention, the substrate particle includes a core and a shell disposed on a surface of the core, and the substrate particle is a core-shell particle.

In a specific aspect of the substrate particle of the present invention, the substrate particle has a carboxyl group on the surface, and the contact angle of water with respect to the substrate particle is 10 ° or more and 90 ° or less.

In a specific aspect of the substrate particle of the present invention, the substrate particle is used to form a conductive layer on the surface of the substrate particle to obtain a conductive particle having the conductive layer.

According to a broad aspect of the present invention, there is provided a conductive particle comprising the above-mentioned base particle and a conductive layer disposed on a surface of the above-mentioned base particle.

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

In a specific aspect of the conductive particle of the present invention, the conductive particle has a protrusion on an outer surface of the conductive layer.

According to a broad aspect of the present invention, there is provided a conductive material comprising conductive particles and a binder resin, wherein the conductive particles comprise the base particles and a conductive layer disposed on the surface of the base particles.

According to a broad aspect of the present invention, there is provided a connection structure comprising: the present invention provides a semiconductor device including a first connection target member having a first electrode on a surface thereof, a second connection target member having a second electrode on a surface thereof, and a connection portion connecting the first connection target member and the second connection target member, wherein a material of the connection portion includes conductive particles, the conductive particles include the base particles, and a conductive layer disposed on the surface of the base particles, and the first electrode and the second electrode are electrically connected by the conductive particles.

Effects of the invention

The substrate particles of the present invention are substrate particles comprising a polyorganosiloxane, wherein the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less, and the substrate particles have a compression elastic modulus of 10000N/mm ² or more and 30000N/mm ² or less when compressed by 10% at 20 ℃. In the substrate particles of the present invention, since the above-described structure is provided, even when the substrate particles are mounted under low pressure, the connection resistance of the obtained connection structure can be reduced, and the conduction reliability can be improved.

Drawings

Fig. 1 is a cross-sectional view schematically showing a substrate particle according to a first embodiment of the present invention.

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

Fig. 3 is a cross-sectional view showing a modified example of conductive particles using the base particles according to the first embodiment of the present invention.

Fig. 4 is a front cross-sectional view schematically showing a connection structure using the conductive particles shown in fig. 2.

Detailed Description

The present invention will be described in detail below.

(Substrate particles)

The substrate particles of the present invention are substrate particles comprising a polyorganosiloxane. In the substrate particles of the present invention, the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less. The substrate particles of the present invention have a compression elastic modulus of 10000N/mm ² to 30000N/mm ² when compressed by 10% at 20 ℃.

In the substrate particles of the present invention, since the above-described structure is provided, even when the substrate particles are mounted under low pressure, recesses (indentations) can be formed satisfactorily on the surface of the electrode of the obtained connection structure, and the contact area between the conductive particles and the electrode can be increased. As a result, the connection resistance of the obtained connection structure can be reduced, and the on-reliability can be improved.

Typically, the polyorganosiloxane has a crosslinked structure. In the polyorganosiloxane, a silicon atom forms a siloxane bond with an oxygen atom adjacent to the silicon atom, and the silicon atoms in adjacent structural units share an oxygen atom with each other. In the present invention, the oxygen atom shared between silicon atoms is denoted as "O _1/2". "

In the present invention, a silicon atom having a 1-crosslinked structure means a silicon atom to which 1-O-Si group is bonded. That is, a silicon atom having a 1-crosslinked structure represents a silicon atom having 1 number of O _1/2 bonded to silicon (having a structure represented by Si-O _1/2 -). The silicon atom having a 2-crosslinking structure means a silicon atom to which 2-O-Si groups are bonded. That is, the silicon atom having a 2-crosslinked structure represents a silicon atom having a number of silicon-bonded O _1/2 of 2 (having a structure represented by Si-O _2/2 -. The silicon atom having a 3-crosslinked structure means a silicon atom to which 3-O-Si groups are bonded. That is, the silicon atom having a 3-crosslinked structure represents a silicon atom having 3 (having a structure represented by Si-O _3/2 -which is bonded to silicon) in number of O _1/2. The silicon atom having a 4-crosslinked structure means a silicon atom to which 4-O-Si groups are bonded. That is, the silicon atom having a 4-crosslinked structure represents a silicon atom having 4 (having a structure represented by Si-O _4/2 -which is bonded to silicon) in number of O _1/2.

In the substrate particles, the polyorganosiloxane contains a silicon atom having a 2-crosslinked structure and a silicon atom having a 3-crosslinked structure. The polyorganosiloxane may or may not contain silicon atoms having a 1-crosslinked structure. The polyorganosiloxane may or may not contain silicon atoms having a 4-crosslinked structure.

In the substrate particles, the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is preferably 0.4 or more, more preferably 0.5 or more, further preferably 0.7 or more, preferably 1.4 or less, more preferably 1.35 or less, further preferably 1.3 or less. When the ratio (the number of silicon atoms having a 2-crosslinked structure/the number of silicon atoms having a 3-crosslinked structure) in the polyorganosiloxane is not less than the lower limit, even when the polyorganosiloxane is attached at a low pressure, a recess (indentation) can be further satisfactorily formed in the surface of the electrode of the obtained connection structure. When the ratio (the number of silicon atoms having a 2-crosslinked structure/the number of silicon atoms having a 3-crosslinked structure) in the polyorganosiloxane is not more than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the polyorganosiloxane is mounted at a low pressure.

In the substrate particles, the total of the number of silicon atoms of the polyorganosiloxane having a 2-crosslinked structure and the number of silicon atoms of the polyorganosiloxane having a 3-crosslinked structure is preferably 1% or more, more preferably 5% or more, further preferably 10% or more, preferably 99% or less, more preferably 95% or less, further preferably 90% or less, of 100% of the number of silicon atoms. The effect of the present invention can be further effectively exhibited when the sum of the number of silicon atoms having a 2-crosslinked structure and the number of silicon atoms having a 3-crosslinked structure is not less than the lower limit and not more than the upper limit.

The ratio of the number of silicon atoms having a 1-crosslinked structure, the number of silicon atoms having a 2-crosslinked structure, the number of silicon atoms having a 3-crosslinked structure, and the number of silicon atoms having a 4-crosslinked structure in the polyorganosiloxane can be determined as follows.

The substrate particles were subjected to solid ²⁹ Si-NMR (measurement frequency: 79.4254MHz, pulse width: 3.7. Mu.s, sample holder: 8mm, sample rotation speed: 7kHz, cumulative number: 3600, measurement temperature: 25 ℃) using an NMR spectrum analyzer. From the obtained results, the ratio of the peak areas of the structures shown by Si-O _1/2 -, si-O _2/2 -, si-O _3/2 -, and Si-O _4/2 -in the polyorganosiloxane in the base material particles was calculated. The ratio of the peak areas obtained was set to be the ratio of the number of silicon atoms having a 1-crosslinked structure, the number of silicon atoms having a 2-crosslinked structure, the number of silicon atoms having a 3-crosslinked structure, and the number of silicon atoms having a 4-crosslinked structure in the polyorganosiloxane. The NMR spectrum analyzer includes "ECX400" manufactured by JEOL.

The polyorganosiloxane can be obtained by a method of condensing an alkoxysilane by hydrolysis, a method of condensing a chlorosilane by hydrolysis, or the like. From the viewpoint of controlling the reaction, the polyorganosiloxane is preferably obtained by a method of condensing an alkoxysilane by hydrolysis. The alkoxysilane is a silane compound having an alkoxy group.

Examples of the alkoxysilane include methyltrimethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1, 6-bis (trimethoxysilyl) hexane, and 3, 3-trifluoropropyltrimethoxysilane. The alkoxysilane may be used in an amount of 1 or 2 or more.

From the viewpoint of suppressing the failure strain, the material of the polyorganosiloxane preferably contains a first alkoxysilane having a polymerizable unsaturated group and a second alkoxysilane having no polymerizable unsaturated group.

The first alkoxysilane has a polymerizable unsaturated group. The polymerizable unsaturated groups in the first alkoxysilane may be 1, or may be 2, or may be 3, or may be 4. In the first alkoxysilane, a group other than an alkoxy group may be a polymerizable unsaturated group. When the first alkoxysilane has a plurality of polymerizable unsaturated groups, the polymerizable unsaturated groups may be the same or different.

From the viewpoint of suppressing the failure strain, the number of carbon atoms of the polymerizable unsaturated group in the first alkoxysilane is preferably 1 or more, more preferably 2 or more, further preferably 3 or more, preferably 10 or less, more preferably 9 or less, further preferably 8 or less. From the viewpoint of suppressing the failure strain, the polymerizable unsaturated group in the first alkoxysilane is preferably vinyl or propenyl, more preferably vinyl.

Examples of the first alkoxysilane include vinyltrimethoxysilane and the like. From the viewpoint of improving the reactivity of the first alkoxysilane with the second alkoxysilane, the first alkoxysilane is preferably vinyltrimethoxysilane.

The second alkoxysilane does not have a polymerizable unsaturated group. The second alkoxysilane preferably has an alkyl group. The number of alkyl groups in the second alkoxysilane may be 1, or may be 2, or may be 3. When the second alkoxysilane has a plurality of alkyl groups, each alkyl group may be the same or different.

The number of carbon atoms of the alkyl group in the second alkoxysilane is preferably 1 or more, more preferably 2 or more, further preferably 3 or more, preferably 10 or less, more preferably 9 or less, further preferably 8 or less, from the viewpoint of improving the compression characteristics (particularly the compression characteristics at the initial stage of compression) of the base material particles. From the viewpoint of improving the reactivity of the first alkoxysilane with the second alkoxysilane, the alkyl group in the second alkoxysilane is preferably an ethyl group or a methyl group, more preferably a methyl group.

Examples of the second alkoxysilane include tetraethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane. The second alkoxysilane is preferably ethyltriethoxysilane or methyltrimethoxysilane, more preferably methyltrimethoxysilane, from the viewpoint of improving the compression characteristics (particularly the compression characteristics at the initial stage of compression) of the base material particles.

The content of the first alkoxysilane in 100% by weight of the polyorganosiloxane material is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 50% by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less, still more preferably 80% by weight or less. When the content of the first alkoxysilane is not less than the lower limit and not more than the upper limit, the compression characteristics (particularly, compression characteristics from the middle stage to the late stage of compression) of the base material particles can be improved.

The content of the second alkoxysilane in 100 wt% of the polyorganosiloxane material is preferably 10 wt% or more, more preferably 20 wt% or more, still more preferably 30 wt% or more, preferably 90 wt% or less, more preferably 80 wt% or less, still more preferably 70 wt% or less. When the content of the second alkoxysilane is not less than the lower limit and not more than the upper limit, the compression characteristics (particularly, the compression characteristics at the initial stage of compression) of the base material particles can be improved.

The content of the polyorganosiloxane in the base material particles is preferably 10 wt% or more, more preferably 20wt% or more, further preferably 30wt% or more, preferably 99 wt% or less, more preferably 95 wt% or less, further preferably 90 wt% or less, based on 100 wt% of the base material particles. When the content of the polyorganosiloxane is not less than the lower limit and not more than the upper limit, the compression characteristics (particularly, the compression characteristics at the initial stage of compression) of the base material particles can be improved.

The polyorganosiloxane may be a copolymer (reactant) of the first alkoxysilane and the second alkoxysilane, or may be a composite of a polymer (reactant) of the first alkoxysilane and a polymer (reactant) of the second alkoxysilane.

From the viewpoint of improving the compression characteristics of the base material particles, it is preferable that the base material particles include a core and a shell disposed on the surface of the core, and are core-shell particles. In the core-shell particle, preferably, the material of the core contains the first alkoxysilane, and the material of the shell contains the second alkoxysilane. In the core-shell particle, the core is preferably a polymer of the first alkoxysilane and the shell is preferably a polymer of the second alkoxysilane. If the core-shell particles satisfy the above-described preferred embodiments, the compression characteristics of the base particles become a further preferred range, and therefore, even when the conductive particles are mounted at a low pressure, the contact area between the conductive particles and the electrode can be increased. As a result, the connection resistance of the obtained connection structure can be reduced, and the on-reliability can be improved.

The particle diameter of the core is preferably 0.1 μm or more, more preferably 1.0 μm or more, preferably 5.0 μm or less, more preferably 4.75 μm or less, further preferably 4.5 μm or less, further preferably 4.0 μm or less, and particularly preferably 3.75 μm or less. When the particle diameter of the core is not less than the lower limit and not more than the upper limit, the compression characteristics of the base material particles can be improved.

The particle diameter of the core means a diameter when the core is in a spherical shape, and means a diameter when a spherical shape corresponding to the volume of the core is assumed when the core is in a shape other than a spherical shape. The particle diameter of the core means an average particle diameter of the core measured by an arbitrary particle diameter measuring device. For example, a particle size distribution measuring apparatus using the principles of laser light scattering, resistance value change, image analysis after photographing, and the like can be used.

The thickness of the shell is preferably 100nm or more, more preferably 200nm or more, preferably 5.0 μm or less, more preferably 3.0 μm or less. When the thickness of the shell is not less than the lower limit and not more than the upper limit, the compression characteristics of the base material particles can be improved.

The thickness of the shell can be determined from the difference between the particle size of the base particles and the average particle size of the core.

The substrate particles preferably have carboxyl groups on the surface thereof, from the viewpoint of facilitating formation of a conductive layer to be described later on the surface of the substrate particles.

The presence or absence of carboxyl groups on the surface of the substrate particles can be evaluated by FT-IR (infrared spectrophotometer).

The contact angle of water with respect to the base particles is preferably 10 ° or more, more preferably 20 ° or more, further preferably 30 ° or more, preferably 100 ° or less, more preferably 90 ° or less, further preferably 80 ° or less. When the contact angle of water with respect to the base particles is not less than the lower limit, a conductive layer to be described later can be easily formed on the surface of the base particles. When the contact angle of water with respect to the base particles is not more than the upper limit, aggregation of the base particles can be suppressed.

The contact angle of water with respect to the substrate particles is preferably a static contact angle. The static contact angle of water with respect to the substrate particles can be determined as follows.

Using a contact angle meter, 100. Mu.L of pure water was dropped onto the substrate particles mounted on the adhesive tape at 20℃to measure the static contact angle. Examples of the contact angle meter include "contact angle meter PG-X" manufactured by MATSUBO.

The static contact angle of the substrate particles with water can be controlled by the kind of alkoxysilane, the firing oxygen concentration at the time of firing the material of the substrate particles, the silane coupling treatment, and the like.

The method for producing the base particles is not particularly limited. The base particles are preferably obtained by firing a material of the base particles.

The firing temperature is preferably 200 ℃ or higher, more preferably 250 ℃ or higher, further preferably 350 ℃ or higher, preferably 850 ℃ or lower, more preferably 750 ℃ or lower, further preferably 650 ℃ or lower. When the firing temperature is not less than the lower limit, the compression characteristics of the base material particles can be improved. When the firing temperature is not more than the upper limit, the fracture resistance of the base material particles can be improved.

The firing oxygen concentration is preferably 0% or more, more preferably 1% or more, further preferably 3% or more, preferably 21% or less, more preferably 20% or less, further preferably 15% or less. When the firing oxygen concentration is not less than the lower limit, the compression characteristics (particularly, compression characteristics from the middle stage to the late stage of compression) of the base material particles can be improved. When the firing oxygen concentration is not more than the upper limit, the fracture resistance of the base material particles can be improved.

The base particles may contain, for example, a base catalyst, an acid catalyst, a surfactant, an inorganic filler, a particle dispersing agent, and the like in addition to the polyorganosiloxane.

Fig. 1 is a cross-sectional view schematically showing a base material particle according to a first embodiment of the present invention.

The substrate particles 1 comprise a polyorganosiloxane. In the substrate particle 1, the ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less. The base material particles 1 have a compression elastic modulus of 10000N/mm ² to 30000N/mm ² when compressed by 10% at 20 ℃.

The modulus of elasticity under compression at 20℃of 10% (10% K value at 20 ℃) is preferably 11000N/mm ² or more, more preferably 12000N/mm ² or more, further preferably 14000N/mm ² or more, preferably 29000N/mm ² or less, more preferably 28000N/mm ² or less, further preferably 25000N/mm ² or less. When the 10% k value at 20 ℃ is not less than the lower limit and not more than the upper limit, even when the electrode is mounted at a low pressure, a recess (indentation) can be formed more favorably on the surface of the electrode of the obtained connection structure.

The modulus of elasticity under compression at 20℃of 20% (20% K value at 20 ℃) is preferably 10500N/mm ² or more, more preferably 11500N/mm ² or more, further preferably 13500N/mm ² or more, preferably 28500N/mm ² or less, more preferably 27500N/mm ² or less, further preferably 24500N/mm ² or less. When the 20% k value at 20 ℃ is not less than the lower limit and not more than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the conductive particles are mounted at a low pressure.

The compression elastic modulus at 20℃under compression of 30% (30% K value at 20 ℃) is preferably 5000N/mm ² or more, more preferably 8000N/mm ² or more, further preferably 12500N/mm ² or more, preferably 27500N/mm ² or less, more preferably 26500N/mm ² or less, further preferably 23500N/mm ² or less. When the 30% k value at 20 ℃ is not less than the lower limit and not more than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the conductive particles are mounted at a low pressure.

The substrate particles preferably exhibit a higher modulus of elasticity in compression at the initial stage of compression (e.g., at 10% compression) than at the mid-stage of compression (e.g., at 20% compression) and at the later stage of compression (e.g., at 30% compression). In the case where the above-described preferred embodiment is satisfied by the base material particles, when the electrodes are electrically connected using the conductive particles having the conductive layer formed on the surface of the base material particles, the recesses (indentations) are preferably formed on the surface of the electrodes due to the initial hardness of the electrodes, and the contact area between the electrodes and the conductive particles can be sufficiently increased due to the softness from the middle stage to the late stage of the compression. Therefore, the connection resistance between the electrodes can be reduced, and the conduction reliability between the electrodes can be improved. For example, even when a connection structure in which electrodes are electrically connected by conductive particles is left to stand under high-temperature and high-humidity conditions for a long period of time, the connection resistance is not easily increased, and connection failure is not easily generated.

The ratio of the absolute value of the difference between the 10% K value at 20 ℃ and the 20% K value at 20 ℃ to the absolute value of the difference between the 20% K value at 20 ℃ and the 30% K value at 20 ℃ is set to be a ratio (absolute value of the difference between the 10% K value at 20 ℃ and the 20% K value at 20/absolute value of the difference between the 20% K value at 20 ℃ and the 30% K value at 20 ℃). The ratio (absolute value of difference between 10% K value at 20 ℃ and 20% K value at 20 ℃ per absolute value of difference between 20% K value at 20 ℃ and 30% K value at 20 ℃) is preferably 1.0 or more and 10.0 or less. The ratio (absolute value of difference between 10% K value at 20 ℃ and 20% K value at 20 ℃ per absolute value of difference between 20% K value at 20 ℃ and 30% K value at 20 ℃) is preferably 1.0 or more, more preferably more than 1.0, further preferably 2.5 or more, preferably 10.0 or less, more preferably 9.5 or less, further preferably 6.0 or less. The effect of the present invention can be further effectively exhibited if the ratio (absolute value of the difference between 10% k value at 20 ℃ and 20% k value at 20 ℃) per absolute value of the difference between 20% k value at 20 ℃ and 30% k value at 20 ℃) is within the above-mentioned range.

The modulus of elasticity under compression at 150℃of 20% (20% K value at 150 ℃) is preferably 2000N/mm ² or more, more preferably 3000N/mm ² or more, further preferably 5000N/mm ² or more, preferably 25000N/mm ² or less, more preferably 22000N/mm ² or less, further preferably 18000N/mm ² or less. When the 20% k value at 150 ℃ is not less than the lower limit and not more than the upper limit, the connection resistance is not easily increased and connection failure is not easily generated even when the obtained connection structure is left under high temperature and high humidity conditions for a long period of time.

The ratio of the compression elastic modulus at 150 ℃ for 20% to the compression elastic modulus at 20% for 20 ℃ is preferably 0.30 or more, more preferably 0.40 or more, further preferably 0.45 or more, preferably 1.0 or less, more preferably 0.80 or less, further preferably 0.70 or less. When the ratio (20% K value at 150 ℃ C./20% K value at 20 ℃ C.) is not less than the lower limit and not more than the upper limit, the connection resistance is not easily increased and connection failure is not easily generated even when the obtained connection structure is left under high-temperature and high-humidity conditions for a long period of time.

The load value at 10% compression at 20 ℃ (10% load value at 20 ℃) is preferably 0.5mN or more, more preferably 0.7mN or more, further preferably 0.9mN or more, preferably 3.5mN or less, more preferably 3.0mN or less, further preferably 2.5mN or less. When the 10% load value at 20 ℃ is not less than the lower limit and not more than the upper limit, even when the electrode is mounted at a low pressure, a recess (indentation) can be formed more favorably on the surface of the electrode of the obtained connection structure.

The load value at 20% compression at 20 ℃ (20% load value at 20 ℃) is preferably 0.9mN or more, more preferably 1.2mN or more, further preferably 1.5mN or more, preferably 8.0mN or less, more preferably 6.5mN or less, further preferably 5.5mN or less. When the 20% load value at 20 ℃ is equal to or higher than the lower limit and equal to or lower than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the conductive particles are mounted at a low pressure.

The load value at 30% compression at 20 ℃ (30% load value at 20 ℃) is preferably 2.0mN or more, more preferably 2.3mN or more, further preferably 2.7mN or more, preferably 11mN or less, more preferably 9.0mN or less, further preferably 7.0mN or less. When the 30% load value at 20 ℃ is not less than the lower limit and not more than the upper limit, rebound after compression can be prevented.

The ratio of the load value at 30% compression at 20 ℃ to the load value at 10% compression at 20 ℃ is preferably 1.0 or more, more preferably 2.0 or more, further preferably 2.5 or more, preferably 4.0 or less, more preferably 3.5 or less, further preferably 3.0 or less. If the ratio (30% load value at 20 ℃ C./10% load value at 20 ℃ C.) is not less than the lower limit and not more than the upper limit, rebound after compression can be prevented.

The compressive elastic modulus of the substrate particles at 20 ℃ (10% k value, 20% k value and 30% k value) and the load value of the substrate particles at 20 ℃ (10% load value, 20% load value and 30% load value) can be determined as follows.

The base material particles were compressed using a micro compression tester under conditions of 20℃at a compression rate of 0.3 mN/sec and a maximum test load of 20mN on the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond). The load value (N) and the compression displacement (mm) at this time were measured. The compressive elastic modulus can be obtained from the obtained measurement value by the following formula. For example, "Fischer Scope H-100" manufactured by Fischer company is used as the micro compression tester.

10% K value, 20% K value or 30% K value at 20℃N/mm ²)＝(3/2^1/2)·F·S^-3/2·R^-1/2

F: load value (N) at 10%, 20% or 30% compression deformation of base material particles

S: compressive displacement (mm) of the base material particles when subjected to 10%, 20% or 30% compressive deformation

R: radius (mm) of substrate particle

The modulus of elasticity under compression (20% k value) of the substrate particles at 150 ℃ can be determined as follows.

The base material particles were compressed using a micro compression tester under conditions of 150℃at a compression rate of 0.3 mN/sec and a maximum test load of 20mN on the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond). The load value (N) and the compression displacement (mm) at this time were measured. The compressive elastic modulus can be obtained from the obtained measurement value by the following formula. For example, "Fischer Scope H-100" manufactured by Fischer company is used as the micro compression tester.

20% K value at 150 ℃ (N/mm ²)＝(3/2^1/2)·F·S^-3/2·R^-1/2

F: load value (N) at 20% compression deformation of base material particles

S: compression displacement (mm) of base material particles at 20% compression deformation

R: radius (mm) of substrate particle

The compression recovery rate at 20℃when compressed by 20% (20% compression recovery rate at 20 ℃) is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, particularly preferably 70% or more. If the 20% compression recovery rate at 20 ℃ is equal to or higher than the lower limit, the conductive particles are likely to follow the change in the interval between the electrodes sufficiently and deform. As a result, poor connection between the electrodes is less likely to occur. The 20% compression recovery at 20 ℃ is preferably less than 100%.

The compression recovery rate at 150℃at 20% (20% compression recovery rate at 150 ℃) is preferably 10% or more, more preferably 20% or more, still more preferably 30% or more, particularly preferably 40% or more. If the 20% compression recovery rate at 150 ℃ is equal to or higher than the lower limit, the conductive particles are likely to follow the deformation sufficiently in response to the fluctuation of the gap between the electrodes. As a result, poor connection between the electrodes is less likely to occur. The 20% compression recovery at 150 ℃ is preferably less than 100%.

The ratio of the compression recovery rate at 150 ℃ when compressed by 20% to the compression recovery rate at 20% when compressed by 20 ℃ is preferably 0.30 or more, more preferably 0.40 or more, preferably 0.90 or less, more preferably 0.80 or less. When the ratio (20% compression recovery rate at 150 ℃ C./20% compression recovery rate at 20 ℃ C.) is not less than the lower limit and not more than the upper limit, the usable temperature range of the base material particles can be widened.

The 20% recovery from compression of the substrate particles at 20 ℃ and 20% recovery from compression at 150 ℃ can be determined as follows.

The substrate particles are spread over the sample stage. For 1 base material particle to be dispersed, a load (reverse load value) was applied to the center direction of the base material particle at 20℃or 150℃on the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond) by using a micro compression tester until the base material particle was compressively deformed by 20%. Then, unloading was performed up to the origin load value (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained by the following equation. The load speed was 0.33 mN/sec. For example, "Fischer Scope H-100" manufactured by Fischer company is used as the micro compression tester.

Compression recovery (%) = [ L2/L1] ×100

L1: compression displacement from origin load value to reverse load value when load is applied

L2: unloading displacement from reverse load value to origin load value at load release

The breaking strain of the base material particles is preferably 10% or more, more preferably 20% or more, preferably 40% or less, more preferably 35% or less. When the fracture strain is equal to or more than the lower limit, the exclusivity of the binder resin and the penetrability of the oxide film of the conductive layer and the electrode become high when the conductive material or the connection structure is used, and the connection resistance becomes further low. When the breaking strain is equal to or less than the upper limit, the contact area between the conductive particles and the electrode becomes larger due to the flexibility in the middle stage of compression, and the connection resistance becomes lower.

In the above-mentioned base material particles, when the compression behavior of the base material particles is evaluated, a point where the displacement amount greatly changes at a certain load value is observed. The load value at the change point is a breaking load value, and the displacement amount is a breaking displacement. The ratio of the failure displacement to the particle diameter before compression (failure displacement/particle diameter before compression) ×100 was defined as failure strain (%). For example, when a failure behavior was observed at a time of a displacement of 1 μm in a particle having a particle diameter of 5 μm before compression, a failure strain was calculated to be 20%. In the case of core-shell particles, the destructive behavior of the shell is generally observed at the beginning of displacement.

The breaking strain can be evaluated based on the measurement of the modulus of elasticity under compression, and can be measured by reading the displacement amount of the discontinuity point of the compression displacement curve. The strain to failure is preferably measured at 20 ℃.

The particle diameter of the base material particles is preferably 0.1 μm or more, more preferably 1.0 μm or more, preferably 500 μm or less, more preferably 100 μm or less, further preferably 50 μm or less, further preferably 10 μm or less, particularly preferably 5.0 μm or less. When the particle diameter of the base material particles is equal to or larger than the lower limit, the contact area between the conductive particles and the electrodes becomes large, so that the conduction reliability between the electrodes can be further improved, and the connection resistance between the electrodes connected via the conductive particles can be further reduced. In addition, when the conductive portions are formed on the surfaces of the base material particles by electroless plating, the aggregated conductive particles can be made less likely to be formed. When the particle diameter of the base material particles is equal to or smaller than the upper limit, the conductive particles are easily sufficiently compressed, and the connection resistance between the electrodes can be further reduced, and the interval between the electrodes can be further reduced.

The particle diameter of the base particles is preferably an average particle diameter, and preferably a number average particle diameter. The particle diameter of the base material particles can be obtained by observing any 50 base material particles with an electron microscope or an optical microscope, calculating an average value of particle diameters of the base material particles, or using a particle size distribution measuring apparatus. In observation with an electron microscope or an optical microscope, the particle diameter of each 1 substrate particle was obtained as a particle diameter based on the equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle diameter based on the equivalent circle diameter of any 50 base material particles was substantially equal to the average particle diameter based on the equivalent sphere diameter. In the particle size distribution measuring apparatus, the particle size of each 1 substrate particle is obtained as the particle size based on the equivalent sphere diameter. The average particle diameter of the base particles is preferably calculated using a particle size distribution measuring apparatus. In the case of measuring the particle diameter of the base particles, the conductive particles can be measured, for example, as follows.

The mixture was added to "TECHN OVIT 4000,4000" manufactured by Kulzer corporation so that the content of the conductive particles became 30% by weight, and dispersed, to prepare an embedded resin body for conductive particle inspection. The cross section of the conductive particles was cut out using an ion milling device (IM 4000, manufactured by hitachi high technology corporation) so as to pass through the vicinity of the center of the base particles embedded in the resin body. Then, using a field emission scanning electron microscope (FE-SEM), the image magnification was set to 25000 times, 50 conductive particles were randomly selected, and the base particles of each conductive particle were observed. The particle diameters of the base particles in the respective conductive particles were measured, and the base particles were arithmetically averaged to obtain the particle diameters of the base particles.

The aspect ratio of the base particles is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. The aspect ratio represents the major/minor diameter.

The use of the base particles is not particularly limited. The substrate particles are suitable for various uses. The substrate particles are preferably used to form a conductive layer on the surface of the substrate particles to obtain conductive particles having the conductive layer. That is, the base particles are preferably base particles for conductive particles. Since the base material particles have excellent compression deformation characteristics and compression fracture characteristics, when an electroconductive layer is formed on the surface of the base material particles and the electrodes are electrically connected to each other by using the electroconductive layer as electroconductive particles, the electroconductive particles are effectively arranged between the substrates or between the electrodes. In addition, in the base material particles, connection failure and display failure are less likely to occur in the connection structure using the conductive particles.

(Conductive particles)

The conductive particles include the base particles and a conductive layer disposed on the surface of the base particles. Since the conductive particles have the above-described structure, the connection resistance of the obtained connection structure can be reduced and the conduction reliability can be improved even when the conductive particles are mounted at a low pressure.

The conductive particles 11 shown in fig. 2 include the base particles 1 and the conductive layer 2 disposed on the surface of the base particles 1. The conductive layer 2 coats the surface of the substrate particles 1. The conductive particles 11 are coated particles in which the surface of the base particle 1 is coated with the conductive layer 2.

Fig. 3 is a cross-sectional view showing a modification of the conductive particles using the base particles according to the first embodiment of the present invention.

The conductive particles 21 shown in fig. 3 include base particles 1, a conductive layer 22, a plurality of core materials 23, and a plurality of insulating materials 24.

The conductive layer 22 is disposed on the surface of the base particle 1. The conductive particles 21 have a plurality of protrusions 21a on the surface. The conductive layer 22 has a plurality of protrusions 22a on the outer surface. In this way, the conductive particles may have protrusions on the surface of the conductive particles or may have protrusions on the outer surface of the conductive layer. The plurality of core substances 23 are arranged on the surface of the base particle 1. A plurality of core substances 23 are buried in the conductive layer 22. The core material 23 is disposed inside the protrusions 21a, 22a. The conductive layer 22 encapsulates a plurality of core materials 23. The protrusions 21a, 22a are formed by swelling the outer surface of the conductive layer 22 with the plurality of core substances 23.

The conductive particles 21 have an insulating substance 24 disposed on the outer surface of the conductive layer 22. At least a part of the area of the outer surface of the conductive layer 22 is covered with an insulating substance 24. The insulating substance 24 is made of an insulating material, and is an insulating particle. In this way, the conductive particles may have an insulating substance disposed on the outer surface of the conductive layer.

The metal used for forming the conductive layer is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, silicon, tungsten, molybdenum, and alloys thereof. Examples of the metal include tin-doped indium oxide (ITO) and solder. In order to further reduce the connection resistance between the electrodes, an alloy containing tin, nickel, palladium, copper, or gold is preferable, and nickel or palladium is preferable.

The conductive layer may be formed of 1 layer, as in the conductive particles 11 and 21. The conductive layer may be formed of a plurality of layers. That is, the conductive layer may have a stacked structure of 2 or more layers. In the case where the conductive layer is formed of a plurality of layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, more preferably a gold layer. In the case where the outermost layer is the preferable conductive layer, the connection resistance between the electrodes is further reduced. In addition, when the outermost layer is a gold layer, corrosion resistance is further improved.

The method for forming the conductive layer on the surface of the base material particles is not particularly limited. Examples of the method for forming the conductive layer include a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and a method of applying a metal powder or paste containing a metal powder and a binder to the surface of a base particle. Since the formation of the conductive layer is simple, a method using electroless plating is preferable. Examples of the method using physical vapor deposition include vacuum vapor deposition, ion plating, ion sputtering, and the like.

The modulus of elasticity under compression (10% K value of the conductive particles at 20 ℃) when the conductive particles are compressed at 10% is preferably 12000N/mm ² or more, more preferably 17000N/mm ² or more, further preferably 23000N/mm ² or more, preferably 37000N/mm ² or less, more preferably 34000N/mm ² or less, further preferably 31000N/mm ² or less. When the 10% k value of the conductive particles at 20 ℃ is not less than the lower limit and not more than the upper limit, even when the conductive particles are mounted at a low pressure, recesses (indentations) can be more favorably formed on the surface of the electrode of the obtained connection structure.

The modulus of elasticity under compression of the conductive particles at 20℃of 20% (20% K value of the conductive particles at 20 ℃) is preferably 8000N/mm ² or more, more preferably 10000N/mm ² or more, further preferably 13000N/mm ² or more, preferably 28500N/mm ² or less, more preferably 27500N/mm ² or less, further preferably 24500N/mm ² or less. When the 20% k value of the conductive particles at 20 ℃ is not less than the lower limit and not more than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the conductive particles are mounted at a low pressure.

The modulus of elasticity under compression of the conductive particles at 20℃of 30% (30% K value of the conductive particles at 20 ℃) is preferably 5500N/mm ² or more, more preferably 8000N/mm ² or more, further preferably 10000N/mm ² or more, preferably 27500N/mm ² or less, more preferably 26500N/mm ² or less, further preferably 23500N/mm ² or less. When the 30% k value of the conductive particles at 20 ℃ is not less than the lower limit and not more than the upper limit, the contact area between the conductive particles and the electrode can be further increased even when the conductive particles are mounted at a low pressure.

The conductive particles preferably exhibit a higher compression elastic modulus at the initial stage of compression (for example, at 10% compression) than at the middle stage of compression (for example, at 20% compression) and at the later stage of compression (for example, at 30% compression). In the case where the above-described preferred embodiment is satisfied with the base particles, in the case where the electrodes are electrically connected using the conductive particles, the recesses (indentations) are formed well on the surfaces of the electrodes due to the initial hardness of the compression, and the contact area between the electrodes and the conductive particles can be sufficiently increased due to the softness from the middle stage to the late stage of the compression. Therefore, the connection resistance between the electrodes can be reduced, and the conduction reliability between the electrodes can be improved. For example, even when a connection structure in which electrodes are electrically connected by conductive particles is left to stand under high-temperature and high-humidity conditions for a long period of time, the connection resistance is not easily increased, and connection failure is not easily generated.

The ratio of the absolute value of the difference between the 10% K value at 20 ℃ and the 20% K value at 20 ℃ of the conductive particles to the absolute value of the difference between the 20% K value at 20 ℃ and the 30% K value at 20 ℃ of the conductive particles was set to be the ratio (absolute value of the difference between the 10% K value at 20 ℃ and the 20% K value at 20 ℃/absolute value of the difference between the 20% K value at 20 ℃ and the 30% K value at 20 ℃). The ratio (absolute value of difference between 10% K value at 20 ℃ and 20% K value at 20 ℃ per absolute value of difference between 20% K value at 20 ℃ and 30% K value at 20 ℃) is preferably 1.0 or more, more preferably more than 1.0, further preferably 2.5 or more, preferably 10.0 or less, more preferably 9.5 or less, further preferably 6.0 or less. The effect of the present invention can be further effectively exhibited if the ratio (absolute value of the difference between 10% k value at 20 ℃ and 20% k value at 20 ℃) per absolute value of the difference between 20% k value at 20 ℃ and 30% k value at 20 ℃) is within the above-mentioned range.

The compressive elastic modulus (10% k value, 20% k value, and 30% k value) of the conductive particles at 20 ℃ can be determined as follows.

The conductive particles were compressed using a micro compression tester under conditions of 20℃at a compression rate of 0.3 mN/sec and a maximum test load of 20mN on the smooth indenter end face of a cylinder (diameter 100 μm, made of diamond). The load value (N) and the compression displacement (mm) at this time were measured. The compressive elastic modulus can be obtained from the obtained measurement value by the following formula. For example, "Fischer Scope H-100" manufactured by Fischer company is used as the micro compression tester.

The conductive particles have a 10% K value, 20% K value or 30% K value (N/mm) ²)＝(3/2^1/2)·F·S^-3/2·R^-1/2

F: load value (N) at 10%, 20% or 30% compression deformation of conductive particles

S: compression displacement (mm) of conductive particles when subjected to 10%, 20% or 30% compression deformation

R: radius (mm) of conductive particle

The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, preferably 500 μm or less, more preferably 100 μm or less, further preferably 50 μm or less, particularly preferably 20 μm or less. When the particle diameter of the conductive particles is equal to or larger than the lower limit and equal to or smaller than the upper limit, the contact area between the conductive particles and the electrodes becomes sufficiently large when the electrodes are connected using the conductive particles, and the conductive particles are less likely to form agglomerates when the conductive layer is formed. Further, the interval between the electrodes connected via the conductive particles does not become excessively large, and the conductive layer is not easily peeled off from the surface of the base material particles. When the particle diameter of the conductive particles is not less than the lower limit and not more than the upper limit, the conductive particles can be suitably used for the purpose of the conductive material.

The thickness of the conductive layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1.0 μm or less, and still more preferably 0.3 μm or less. In the case where the conductive layer is a plurality of layers, the thickness of the conductive layer is the thickness of the entire conductive layer. When the thickness of the conductive layer is not less than the lower limit and not more than the upper limit, sufficient conductivity can be obtained, and the conductive particles are not excessively hard, and the conductive particles are sufficiently deformed at the time of connection between the electrodes.

When the conductive layer is formed of a plurality of layers, the thickness of the conductive layer of the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.50 μm or less, more preferably 0.10 μm or less. When the thickness of the outermost conductive layer is equal to or greater than the lower limit and equal to or less than the upper limit, the coating of the outermost conductive layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes further decreases. In addition, in the case where the outermost layer is a gold layer, the thinner the gold layer is, the lower the cost is.

The thickness of the conductive layer can be measured, for example, by observing a cross section of the conductive particles using a Transmission Electron Microscope (TEM).

The conductive particles may have protrusions on the surface. The conductive particles may have protrusions on an outer surface of the conductive layer. The protrusion is preferably a plurality. An oxide film is formed on the surface of the conductive layer and the surface of the electrode connected by the conductive particles. In the case of using conductive particles having protrusions, the oxide film can be effectively removed by the protrusions by disposing conductive particles between electrodes and pressing them. Therefore, the electrode can be more reliably brought into contact with the conductive layer of the conductive particle, and the connection resistance between the electrodes can be reduced. In addition, in the case where the conductive particles have an insulating substance on the surface or in the case where the conductive particles are dispersed in a binder resin and used as a conductive material, the insulating substance or the binder resin between the conductive particles and the electrode can be effectively removed by the protrusions of the conductive particles. Therefore, the conduction reliability between the electrodes can be improved.

As a method for forming protrusions on the surface of the conductive particles, there may be mentioned: a method of forming a conductive layer by electroless plating after attaching a core material to the surface of the base material particles; and a method in which a conductive layer is formed on the surface of the base material particles by electroless plating, a core material is attached, and then a conductive layer is formed by electroless plating. In addition, the core material may not be used in order to form the protrusions.

The conductive particles may include an insulating substance disposed on an outer surface of the conductive layer. In this case, if the conductive particles are used for connection between the electrodes, short-circuiting between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are in contact, an insulating material is present between a plurality of electrodes, so that it is possible to prevent a short circuit between electrodes that are laterally adjacent to each other, not between upper and lower electrodes. When the electrodes are connected, the conductive particles are pressurized by 2 electrodes, so that the insulating material between the conductive layer of the conductive particles and the electrodes can be easily removed. In the case where the conductive particles have protrusions on the surface of the conductive layer, the insulating substance between the conductive layer of the conductive particles and the electrode can be more easily removed. The insulating material is preferably an insulating resin layer or insulating particles, more preferably insulating particles. The insulating particles are preferably insulating resin particles.

(Conductive Material)

The conductive material includes conductive particles and a binder resin. In the conductive material, the conductive particles include the base particles and a conductive layer disposed on the surfaces of the base particles. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is suitable for electrical connection of the electrodes. The conductive material is preferably a circuit connection material.

The binder resin is not particularly limited. As the binder resin, a known insulating resin can be used. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. The binder resin may be used in an amount of 1 or 2 or more.

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

The conductive material may contain various additives such as a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, and a flame retardant, in addition to the conductive particles and the binder resin.

The method for dispersing the conductive particles in the binder resin is not particularly limited. As a method for dispersing the conductive particles in the binder resin, a conventionally known dispersing method can be used. Examples of the method for dispersing the conductive particles in the binder resin include the following methods. And a method in which the conductive particles are added to the binder resin and then kneaded and dispersed by a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, and then added to the binder resin, and kneaded and dispersed by a planetary mixer or the like. And a method in which the binder resin is diluted with water, an organic solvent, or the like, and then the conductive particles are added and kneaded and dispersed by a planetary mixer or the like.

The conductive material can be used as a conductive paste, a conductive film, or the like. In the case where the conductive material of the present invention is a conductive film, a film containing no conductive particles may be stacked over the conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

The content of the binder resin in 100 wt% of the conductive material is preferably 10 wt% or more, more preferably 30 wt% or more, further preferably 50 wt% or more, particularly preferably 70 wt% or more, preferably 99.99 wt% or less, and more preferably 99.9 wt% or less. If the content of the binder resin is not less than the lower limit and not more than the upper limit, conductive particles are effectively arranged between the electrodes, and the connection reliability of the members to be connected by the conductive material is further improved.

The content of the conductive particles in the conductive material is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, preferably 40 wt% or less, more preferably 20 wt% or less, and further preferably 10 wt% or less, based on 100 wt% of the conductive material. When the content of the conductive particles is not less than the lower limit and not more than the upper limit, the conduction reliability between the electrodes is further improved.

(Connection Structure)

The connection structure can be obtained by connecting the connection target members using the conductive particles or using a conductive material containing the conductive particles and a binder resin.

The connection structure is provided with: a first connection object member having a first electrode on a surface thereof; a second connection object member having a second electrode on a surface thereof; and a connection unit that connects the first connection target member and the second connection target member. In the connection structure, the material of the connection portion includes conductive particles, and the conductive particles include the base material particles and a conductive layer disposed on the surface of the base material particles. In the connection structure, the first electrode and the second electrode are electrically connected by the conductive particles. The connection portion is preferably formed of conductive particles or a conductive material including the conductive particles and a binder resin.

Preferably, the first connection object member has a first electrode on a surface thereof. Preferably, the second connection object member has a second electrode on a surface thereof. Preferably, the first electrode and the second electrode are electrically connected by the conductive particles.

The connection structure 51 shown in fig. 4 includes a first member to be connected 52, a second member to be connected 53, and a connection portion 54 that connects the first member to be connected 52 and the second member to be connected 53. The connection portion 54 is formed of a conductive material including the conductive particles 11 and a binder resin. In fig. 4, the conductive particles 11 are schematically shown for convenience of illustration. Instead of the conductive particles 11, other conductive particles such as the conductive particles 21 may be used.

The first connection object member 52 has a plurality of first electrodes 52a on a surface (upper surface). The second connection object member 53 has a plurality of second electrodes 53a on a surface (lower surface). The first electrode 52a and the second electrode 53a are electrically connected by 1 or more conductive particles 11. Therefore, the first and second members to be connected 52, 53 are electrically connected by the conductive particles 11.

The method for producing the connection structure is not particularly limited. As an example of a method for manufacturing the connection structure, a method in which the conductive material is disposed between the first connection object member and the second connection object member to obtain a laminate, and then the laminate is heated and pressurized, and the like can be given. The pressure of the pressurization was 9.8X10 ⁴Pa～4.9×10⁶ Pa. The heating temperature is 120-220 ℃. The pressurizing pressure for connecting the electrodes of the flexible printed board, the electrodes arranged on the resin film, and the electrodes of the touch panel is about 9.8X10 ⁴Pa～1.0×10⁶ Pa. In the connection structure according to the present invention, since the structure is provided, even when the connection structure is mounted at a low pressure, the connection resistance can be reduced, and the conduction reliability can be improved.

Specifically, the connection target member includes electronic components such as a semiconductor chip, a capacitor, a diode, and the like, and electronic components such as a printed board, a flexible printed board, a glass epoxy board, a glass substrate, and the like, and a circuit board and the like. The conductive material is preferably a conductive material for connecting electronic components. The conductive paste is a paste-like conductive material, and is preferably applied to the member to be connected in a paste-like state.

The conductive particles and the conductive material are also suitable for use in a touch panel. Therefore, the connection target member is preferably a flexible substrate or a connection target member having an electrode disposed on a surface of a resin film. The connection target member is preferably a flexible substrate, and preferably a connection target member in which an electrode is disposed on a surface of a resin film. In the case where the flexible substrate is a flexible printed substrate or the like, the flexible substrate generally has an electrode on a surface.

Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, and a tungsten electrode. In the case where the connection target member is a flexible substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. In the case where the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In the case where the electrode is an aluminum electrode, the electrode may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a 3-valent metal element, zinc oxide doped with a 3-valent metal element, and the like. Examples of the 3-valent metal element include Sn, al, and Ga.

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

The following materials were prepared.

(Polyorganosiloxane Material)

A first alkoxysilane: vinyl trimethoxy silane (number of carbon atoms of polymerizable unsaturated group: 2)

Second alkoxysilane: methyltrimethoxysilane (number of carbon atoms of alkyl group: 1)

(1) Preparation of substrate particles

Example 1

To a 5000mL separable flask equipped with a thermometer, a dropping device, and a stirrer, 1500g of an aqueous ammonia solution of 0.13% by weight and 47 parts by weight of a second alkoxysilane (methyltrimethoxysilane) were added, and stirring was performed at 20 rpm. Subsequently, 53 parts by weight of a first alkoxysilane (vinyltrimethoxysilane) was slowly added, and after hydrolysis and polymerization reaction were performed with stirring at 20rpm, 10mL of a 25 wt% aqueous ammonia solution was slowly added, and particles were separated from the aqueous ammonia solution, to obtain condensate particles. The obtained condensate particles were fired at a firing temperature of 300℃and a firing oxygen concentration of 20% for 2 hours to obtain base particles (core-shell particles) having carboxyl groups on the surface.

Example 2

Into a 5000mL separable flask equipped with a thermometer, a dropping device, and a stirrer, 1500g of a 0.13 wt% aqueous ammonia solution and 68 parts by weight of a first alkoxysilane (vinyltrimethoxysilane) were charged, and stirring was performed at 20 rpm. Next, 32 parts by weight of a second alkoxysilane (methyltrimethoxysilane) was slowly added, and after hydrolysis and polymerization reaction were performed with stirring at 20rpm, 10mL of a25 wt% aqueous ammonia solution was slowly added, and particles were separated from the aqueous ammonia solution, to obtain condensate particles. The obtained condensate particles were fired at a firing temperature of 300℃and a firing oxygen concentration of 20% for 2 hours to obtain base particles (core-shell particles) having carboxyl groups on the surface.

Examples 3 to 7

Base particles (core-shell particles) having carboxyl groups on the surfaces were obtained in the same manner as in example 1 except that the addition amounts of the first and second alkoxysilanes, the firing temperatures of the condensate particles, and the firing oxygen concentrations were changed as shown in tables 1 and 3.

Example 8

To a 5000mL separable flask equipped with a thermometer, a dropping device, and a stirrer, 1500g of an aqueous ammonia solution of 0.13 wt%, 35 parts by weight of a first alkoxysilane (vinyltrimethoxysilane), and 65 parts by weight of a second alkoxysilane (methyltrimethoxysilane) were slowly added. After hydrolysis and polymerization reaction were carried out with stirring at 20rpm, 10mL of 25 wt% aqueous ammonia solution was slowly added, and the particles were separated from the aqueous ammonia solution to obtain condensate particles. The obtained condensate particles were fired at a firing temperature of 580 ℃ and a firing oxygen concentration of 15% for 2 hours to obtain base particles having carboxyl groups on the surface, which were not core-shell particles.

Examples 9 to 11 and comparative example 2

Base particles other than core-shell particles were obtained in the same manner as in example 8 except that the firing temperature of the condensate particles was changed as shown in tables 3,5 and 7 and the firing oxygen concentration was changed to 0%.

Comparative example 1

To 70 parts by weight of divinylbenzene copolymer resin particles (MICROPEARL SP-203, manufactured by water chemical industry Co., ltd.) were added 30 parts by weight of tetraethoxysilane, and after hydrolysis and polymerization reaction were carried out with stirring at 30rpm, 2.4mL of 25% by weight aqueous ammonia solution was slowly added, and the particles were separated from the aqueous ammonia solution to obtain base particles (core-shell particles).

Comparative example 3

In a 2L flask equipped with a stirrer, a reflux condenser and a thermometer were charged 110.0g of benzoguanamine, 160.0g of 37 wt% formalin and 620g of water, and pH was adjusted to 8.8 with 25 wt% aqueous ammonia to obtain a mixture. The resulting mixture was heated while stirring, and the temperature was kept at 70℃for 30 minutes to prepare an aqueous solution of an initial condensate of benzoguanamine. Next, a 10 wt% aqueous solution of p-toluenesulfonic acid monohydrate was added to the aqueous solution of the initial condensate obtained while maintaining the temperature at 70 ℃, and the pH was adjusted to 6.0. Then, the temperature was raised to 90℃and the curing reaction was continued for 3 hours. After cooling, the obtained reaction solution was filtered and dried to obtain white benzoguanamine resin particles.

(2) Preparation of conductive particles

(Examples 1 to 11 and comparative examples 1 to 3)

The obtained base particles were added to 500 parts by weight of distilled water and dispersed, whereby a dispersion was obtained. Further, as a nickel plating solution, a nickel plating solution (pH 8.5) containing 0.14mol/L of nickel sulfate, 0.46mol/L of dimethylamine borane, and 0.2mol/L of sodium citrate was prepared. The resulting dispersion was stirred at 60℃and the nickel plating solution was added dropwise to the dispersion at a dropping rate of 30 mL/min for 10 minutes to thereby effect electroless nickel-boron alloy plating. Then, the dispersion was filtered, the particles were removed, washed with water, and dried, whereby conductive particles having a conductive layer (nickel-boron alloy, thickness 0.1 μm) disposed on the surface of the base particles were obtained.

Example 12

The base particles obtained in example 4 were dispersed in 500 parts by weight of distilled water, to thereby obtain a dispersion. Next, 1g of nickel particle slurry (average particle diameter: 150 nm) was added to the dispersion over 3 minutes to obtain base particles to which the core material was attached. Further, as a nickel plating solution, a nickel plating solution (pH 5.0) containing 0.19mol/L of nickel sulfate, 0.21mol/L of sodium hypophosphite and 0.08mol/L of sodium citrate was prepared. While stirring the obtained dispersion at 45 ℃, the nickel plating solution was added dropwise to the dispersion at a dropping rate of 50 ml/min, and electroless nickel plating was performed. Then, the dispersion was filtered, the particles were removed, washed with water, and dried, whereby conductive particles having a nickel-phosphorus conductive layer (thickness 0.1 μm) disposed on the surface of the base particles were obtained.

Example 13

10 Parts by weight of the base particles obtained in example 4 were added to 100 parts by weight of an alkali solution containing 5% by weight of a palladium catalyst solution, dispersed by using an ultrasonic disperser, and the solution was filtered to remove the base particles. Next, the substrate particles were added to 100 parts by weight of a1 wt% dimethylamine borane solution to activate the surfaces of the substrate particles. The surface-activated base particles were sufficiently washed with water, and then added to 500 parts by weight of distilled water to disperse them, thereby obtaining a dispersion.

As the electroless high-purity nickel plating solution, a plating solution in which a mixed solution containing 0.21mol/L of nickel chloride, 1.54mol/L of hydrazine sulfate, 0.32mol/L of boric acid and 0.08mol/L of sodium citrate was adjusted to pH10.5 with sodium hydroxide was prepared. 500ml of the electroless high-purity nickel plating solution was added dropwise to the dispersion at a dropping rate of 30 ml/min, and electroless high-purity nickel plating was performed. The reaction temperature at this time was set to 60 ℃. Thereafter, the mixture was stirred until the pH was stabilized, and the foaming of hydrogen was stopped. Then, the dispersion was filtered, the particles were removed, washed with water, and dried, whereby conductive particles having a conductive layer (high purity nickel, thickness 0.1 μm) disposed on the surface of the base particles were obtained. The conductive portion in the obtained conductive particle has a plate-like protrusion on the outer surface.

Example 14

10 Parts by weight of the base particles obtained in example 4 were added to 100 parts by weight of an alkali solution containing 5% by weight of a palladium catalyst solution, dispersed by using an ultrasonic disperser, and the solution was filtered to remove the base particles. Next, the substrate particles were added to 100 parts by weight of a1 wt% dimethylamine borane solution to activate the surfaces of the substrate particles. After the surface-activated base particles were sufficiently washed with water, they were dispersed by adding 500 parts by weight of distilled water, whereby a suspension (0) was obtained.

Nickel plating solution (1) (pH 8.5) containing 0.14mol/L of nickel sulfate, 0.46mol/L of dimethylamine borane and 0.2mol/L of sodium citrate was prepared. While stirring the suspension (0) at 60 ℃, the nickel plating solution (1) was slowly dropped into the suspension (0), and electroless nickel-boron alloy was performed to obtain a suspension (1).

Next, a nickel plating solution (2) (pH 8.0) containing 0.14mol/L of nickel sulfate and 0.45mol/L of hydrazine was prepared. And (3) slowly dropwise adding the nickel plating solution (2) into the suspension (1) while stirring the suspension (1) at 65 ℃ to carry out electroless nickel plating to obtain the suspension (2).

Nickel plating solution (3) (pH 8.0) containing 0.14mol/L of nickel sulfate, 0.09mol/L of sodium stannate trihydrate and 0.45mol/L of sodium gluconate was prepared. And (3) slowly dropwise adding the nickel plating solution (3) into the suspension (2) while stirring the suspension (2) at 65 ℃ to perform electroless nickel-tin alloy plating to obtain the suspension (3).

Then, the suspension (3) was filtered, and the particles were removed, washed with water, and dried, whereby conductive particles having a conductive layer (nickel-tin alloy, thickness 0.1 μm) disposed on the surface of the base particles were obtained.

(3) Preparation of connection Structure

The following materials were mixed. 10 parts by weight of bisphenol A type epoxy resin (EPIKOTE 1009, mitsubishi chemical corporation). 40 parts by weight of an acrylic rubber (weight average molecular weight: about 80 ten thousand) and 200 parts by weight of methyl ethyl ketone. 50 parts by weight of a microcapsule curing agent (HX 3941HP, manufactured by Asahi chemical electronic materials Co., ltd.). 2 parts by weight of a silane coupling agent (SH 6040, manufactured by Dow Corning Toray Silicone Co.). To the obtained mixture, conductive particles were added so that the content became 3 wt% and dispersed, to obtain a resin composition.

The obtained resin composition was applied to a 50 μm thick PET (polyethylene terephthalate) film, which was subjected to a mold release treatment on one side, and dried with hot air at 70℃for 5 minutes to prepare an anisotropic conductive film. The thickness of the obtained anisotropic conductive film was 12. Mu.m.

The resulting anisotropic conductive film was cut into a size of 5mm×5 mm. The cut anisotropic conductive film was adhered to a substantially central portion of an aluminum electrode of a glass substrate (width 3cm, length 3 cm) provided with an aluminum electrode (height 0.2 μm, L/s=20 μm/20 μm) having a lead wire for resistance measurement on one side. Next, 2 layers of flexible printed boards (width 2cm, length 1 cm) provided with the same aluminum electrode were aligned and bonded so that the electrodes overlapped with each other. The laminate of the glass substrate and 2 layers of flexible printed substrates was thermally bonded under pressure conditions of 40N, 180 ℃ and 15 seconds to obtain a connection structure.

(Evaluation)

(1) Ratio in polyorganosiloxane (number of silicon atoms having 2-crosslinked structure/number of silicon atoms having 3-crosslinked structure)

The obtained substrate particles were subjected to solid ²⁹ Si-NMR measurement (measurement frequency: 79.4254MHz, pulse width: 3.7. Mu.s, sample holder: 8mm, sample rotation speed: 7kHz, cumulative number: 3600, measurement temperature: 25 ℃) using an NMR spectrum analyzer (ECX 400, JEOL). By the above method, the ratio (number of silicon atoms having 2-crosslinked structure/number of silicon atoms having 3-crosslinked structure) in the polyorganosiloxane was determined.

(2) Particle diameter of base material particles

The obtained base particles were measured for about 100000 particle diameters by using a particle size distribution measuring apparatus (product of Beckmann Kort corporation, "Mul tisizer" and an average particle diameter was measured.

(3) The modulus of elasticity under compression (10% K value at 20 ℃, 20% K value at 20 ℃, 30% K value at 20 ℃ and 20% K value at 150) and the compressive load value (10% load value at 20 ℃, 20% load value at 20 ℃ and 30% load value at 20 ℃) of the substrate particles

The compressive elastic modulus and the compressive load value of the obtained base material particles were measured by the above method using a micro compression tester (Fischer Scope H-100, manufactured by Fischer). Further, the ratio (20% K value at 150 ℃ C./20% K value at 20 ℃ C.), the ratio (absolute value of the difference between 10% K value at 20 ℃ C. And 20% K value at 20 ℃ C./absolute value of the difference between 20% K value at 20 ℃ C. And 30% K value at 20 ℃ C.), and the ratio (30% load value at 20 ℃ C./10% load value at 20 ℃ C.) were determined.

(4) Compression recovery rate (20% compression recovery rate at 20 ℃ and 20% compression recovery rate at 150 ℃) and failure strain of the base material particles

The compression recovery rate and the fracture strain of the obtained base material particles were measured by the method using a micro compression tester (Fischer scope H-100, manufactured by Fischer Co.) under conditions of 20℃and 150 ℃. Further, the ratio (20% compression recovery at 150 ℃ C./20% compression recovery at 20 ℃ C.) was determined.

(5) Static contact angle of water with substrate particles

The static contact angle was measured by dropping 100. Mu.L of pure water onto the substrate particles mounted on the adhesive tape at 20℃using a contact angle meter (manufactured by MATSUBO Co., ltd. "contact angle meter PG-X").

(6) Compressive elastic modulus of conductive particles (10% K value at 20 ℃, 20% K value at 20 ℃ and 30% K value at 20 ℃)

The compressive elastic modulus of the obtained conductive particles was measured by the above method using a micro compression tester (Fischer Scope H-100, manufactured by Fischer Co.).

(7) State of indentation

In the obtained connection structure, the electrode provided on the glass substrate was observed from the glass substrate side of the connection structure using a differential interference microscope, and the presence or absence of the formation of an indentation in the electrode in contact with the conductive particles was observed. After leaving the mixture at 85℃for 100 hours in 85% air, the presence or absence of formation of an indentation in the electrode contacted with the conductive particles was similarly observed. The state of the indentation is determined according to the following criteria.

[ Criterion for determining indentation State ]

O: of the 50 electrodes, the number of electrodes in which no indentation clearly appears in the connection structure before heating was 0, and the number of electrodes in which no indentation clearly appears in the connection structure after heating was 0

O: the number of electrodes of 50 electrodes, in which no indentation clearly appears in the connection structure before heating, is 0, and the number of electrodes, in which no indentation clearly appears in the connection structure after heating, is 1 or more and less than 5

O: of the 50 electrodes, the number of electrodes in which no mark appears clearly in the connection structure before heating is 0, and the number of electrodes in which no mark appears clearly in the connection structure after heating is 5 or more

Delta: of the 50 electrodes, the number of electrodes in which no mark appears clearly in the connection structure before heating is 1 or more and less than 5

X: of the 50 electrodes, the number of electrodes in which no mark appears clearly in the connecting structure before heating is 5 or more

(8) Contact area between conductive particles and electrode

The obtained connection structure was observed for the cross sections of 3 conductive particles using a focused ion beam scanning electron microscope (FIB-SEM), and the average of the ratio of the lengths of the portions of the conductive particles in contact with the upper and lower electrodes was calculated in 100% of the circumference of the conductive particles. The contact area between the conductive particles and the electrode was determined according to the following criteria.

[ Evaluation criterion of contact area of conductive particles with electrode ]

O: the ratio of the length of the portion of the conductive particles in contact with the upper and lower electrodes is 50% or more

O: the ratio of the length of the portion of the conductive particles in contact with the upper and lower electrodes is less than 50% and 40% or more

O: the length ratio of the conductive particles to the parts contacting the upper and lower electrodes is less than 40% and 30% or more

Delta: the ratio of the length of the portion of the conductive particles in contact with the upper and lower electrodes is less than 30% and 20% or more

X: the length ratio of the conductive particles to the parts contacting the upper and lower electrodes is less than 20%

(9) Initial connecting resistance

The connection resistance a between the opposed electrodes of the obtained connection structure was measured by the 4-terminal method. The initial connection resistance was determined according to the following criteria.

[ Evaluation criterion of initial connection resistance ]

O: the connection resistance A is below 2.0Ω

O: the connection resistance A exceeds 2.0Ω and is 3.0Ω or less

O: the connection resistance A exceeds 3.0Ω and is 5.0Ω or less

Delta: the connection resistance A exceeds 5.0Ω and is 10.0Ω or less

X: the connection resistance A exceeds 10.0Ω

(10) Conduction reliability

The resulting joined structure was left at 85℃and 85% (under high temperature and high humidity) for 500 hours. The connection resistance B between the opposed electrodes of the connection structure after being placed was measured by the 4-terminal method. The conduction reliability of the connection structure is determined according to the following criteria.

[ Evaluation criterion of conduction reliability ]

O: the ratio of the connection resistance B to the connection resistance A is less than 1.0

O: the ratio of the connection resistance B to the connection resistance A is 1.0 or more and less than 1.5

O: the ratio of the connection resistance B to the connection resistance A is 1.5 or more and less than 2.0

Delta: the ratio of the connection resistance B to the connection resistance A is more than 2.0 and less than 5.0

X: the ratio of the connection resistance B to the connection resistance A is more than 5.0

Details and results of the base material particles and the conductive particles are shown in tables 1 to 8 below.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

TABLE 7

TABLE 8

Symbol description

1 … Substrate particles

2 … Conductive layer

11 … Conductive particles

21 … Conductive particles

21A … projection

22 … Conductive layer

22A … projection

23 … Core material

24 … Insulating material

51 … Connection structure

52 … First connection object part

52A … first electrode

53 … Second connection object parts

53A … second electrode

54 … Connection

Claims

1. A substrate particle comprising a polyorganosiloxane, wherein,

The ratio of the number of silicon atoms having a 2-crosslinked structure to the number of silicon atoms having a 3-crosslinked structure in the polyorganosiloxane is 0.3 or more and 1.5 or less,

The substrate particles have a compression elastic modulus of 10000N/mm ² to 30000N/mm ² when compressed by 10% at 20 ℃.

2. The substrate particle according to claim 1, wherein the ratio of the load value at 30% compression at 20 ℃ to the load value at 10% compression at 20 ℃ is 4.0 or less,

The breaking strain is 10% to 40%.

3. The substrate particle according to claim 1 or 2, wherein the ratio of the absolute value of the difference between the compression elastic modulus at 20 ℃ and the compression elastic modulus at 20% at 20 ℃ to the absolute value of the difference between the compression elastic modulus at 20% at 20 ℃ and the compression elastic modulus at 30% at 20 ℃ is 1.0 or more.

4. The substrate particle according to any one of claims 1 to 3, wherein a ratio of an absolute value of a difference between a compression elastic modulus at 20 ℃ and a compression elastic modulus at 20% at 20 ℃ to an absolute value of a difference between a compression elastic modulus at 20% at 20 ℃ and a compression elastic modulus at 30% at 20 ℃ is 1.0 or more and 10.0 or less.

5. The base material particle according to any one of claims 1 to 4, wherein the ratio of the compression elastic modulus at 150 ℃ when compressed by 20% to the compression elastic modulus at 20 ℃ when compressed by 20% is 0.40 or more.

6. The substrate particle according to any one of claim 1 to 5, which has a compression recovery rate of 60% or more when compressed at 20 ℃ by 20%,

The ratio of the compression recovery rate of the base material particles when compressed at 150 ℃ to the compression recovery rate when compressed at 20% at 20 ℃ is 0.30 to 0.90.

7. The substrate particle according to any one of claims 1 to 6, which has a particle diameter of 1.0 μm or more and 5.0 μm or less.

8. The substrate particle according to any one of claims 1 to 7, wherein,

The polyorganosiloxane material comprises a first alkoxysilane having a polymerizable unsaturated group and a second alkoxysilane having no polymerizable unsaturated group.

9. The substrate particle according to any one of claim 1 to 8, comprising a core and a shell disposed on a surface of the core,

The substrate particles are core-shell particles.

10. The substrate particle according to any one of claims 1 to 9, wherein,

The substrate particles have carboxyl groups on the surface,

The contact angle of the water with respect to the substrate particles is 10 DEG to 90 deg.

11. The substrate particle according to any one of claims 1 to 10, wherein,

The substrate particles are used for forming a conductive layer on the surface of the substrate particles to obtain conductive particles having the conductive layer.

12. A conductive particle is provided with:

the substrate particle of any one of claims 1 to 11; and

And a conductive layer disposed on the surface of the base material particles.

13. The conductive particle according to claim 12, comprising:

an insulating material disposed on an outer surface of the conductive layer.

14. The conductive particle according to claim 12 or 13, which has a protrusion on an outer surface of the conductive layer.

15. A conductive material comprising conductive particles and a binder resin,

The conductive particles comprise the substrate particles according to any one of claims 1 to 11, and a conductive layer disposed on the surface of the substrate particles.

16. A connection structure is provided with:

A first connection object member having a first electrode on a surface thereof;

a second connection object member having a second electrode on a surface thereof; and

A connection portion for connecting the first connection object member and the second connection object member,

The material of the connection portion comprises conductive particles,

The conductive particles comprising the substrate particles according to any one of claims 1 to 11, and a conductive layer disposed on the surface of the substrate particles,

The first electrode and the second electrode are electrically connected by the conductive particles.