JP2023007156A - Resin particle, conductive particle, conductive material, and connection structure - Google Patents

Abstract

To provide resin particles which effectively control a gap even under high temperature environment when used as a spacer, and can prevent damage of a connection target member.SOLUTION: Resin particles have a coefficient of linear thermal expansion at 100-200°C of 300 ppm/°C or less, a compressive elastic modulus when compressed by 10% of 100 N/mm2 or more and 5000 N/mm2 or less, and a compressive elastic modulus when compressed by 30% of 100 N/mm2 or more and 2000 N/mm2 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to resin particles. The present invention also relates to a conductive particle, a conductive material, and a connection structure using the resin particles.

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

The anisotropic conductive material is used to electrically connect electrodes of various members to be connected, such as flexible printed circuit boards (FPC), glass substrates, glass epoxy substrates, and semiconductor chips, to obtain connection structures. ing. Further, as the conductive particles, conductive particles having resin particles and conductive portions arranged on the surfaces of the resin particles are sometimes used. A connection structure using such conductive particles is used in electronic devices such as display devices, and is also used in automobile engines, motors, and the like. Automobile engines and motors are much hotter than parts of electronic devices. Therefore, connection structures, conductive materials, conductive particles, and resin particles used in engine parts and motor parts are required to have high heat resistance so as not to be decomposed or melted by heat.

Further, the liquid crystal display element is configured by disposing liquid crystal between two glass substrates. In the liquid crystal display element, a spacer is used as a gap control material in order to keep the gap between the two glass substrates uniform and constant. Furthermore, it is desirable that the spacers do not damage the glass substrate. Moreover, it is preferable that the spacer is not destroyed during mounting. Resin particles are generally used as the spacer.

Patent Document 1 below describes a method for producing polyurethane beads that are excellent in flexibility and heat resistance in a low temperature range. The above production method includes the steps of dispersing a bead raw material containing a polyol component and an isocyanate component into particles in water containing a suspension stabilizer and reacting them to prepare a polyurethane bead suspension; and a step of solid-liquid separation of the turbid liquid. Moreover, the polyol component contains a polyester polyol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid.

JP 2010-024319 A

When the polyurethane beads of Patent Document 1 are used as the resin particles, the heat resistance of the resin particles, the conductive particles, etc. can be improved to some extent. However, since polyurethane beads generally tend to expand due to heat, when polyurethane beads are used as resin particles (spacers) in a high temperature environment (for example, 100° C. to 200° C.), it is necessary to control the gap uniformly and constantly. is difficult and may damage the member to be connected such as the PET substrate. Furthermore, in the conductive particles and the connection structure obtained using the resin particles, the resin particles are likely to expand due to heat, so when used in a high temperature environment, the conductive particles (especially the conductive portion) Cracks may occur, and voids (bubbles) may occur around the conductive particles in the connection structure. As a result, the connection reliability of the connection structure may be lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide resin particles that, when used as a spacer, can effectively control the gap even in a high-temperature environment and prevent damage to members to be connected. Another object of the present invention is to provide conductive particles, a conductive material, and a connection structure using the resin particles. Another object of the present invention is to provide resin particles that can suppress the occurrence of cracks in the resulting conductive particles even in a high-temperature environment. A further object of the present invention is to provide resin particles that can suppress the generation of voids in the resulting bonded structure even in a high-temperature environment.

According to a broad aspect of the present invention, the linear thermal expansion coefficient at 100 ° C. to 200 ° C. is 300 ppm / ° C. or less, and the compression elastic modulus when compressed by 10% is 100 N / mm ² or more and 5000 N / mm ² or less. Provided are resin particles having a compressive modulus of 100 N/mm ² or more and 2000 N/mm ² or less when compressed by 30%.

In a specific aspect of the present invention, the resin particles have a coefficient of linear thermal expansion of 100 ppm/°C or less at 100°C to 200°C.

In a specific aspect of the present invention, the resin particles have a ratio of the compression modulus at 10% compression to the compression modulus at 30% compression of 1.5 or more and 3.0 or less.

In a specific aspect of the resin particles according to the present invention, the thermal decomposition temperature is 400° C. or higher.

In a specific aspect of the resin particles according to the present invention, the material of the resin particles contains a polymer having imide groups formed by polymerization of two or more polymerizable monomers.

In a specific aspect of the resin particles according to the present invention, the aspect ratio is 1.0 or more and 1.1 or less.

In a specific aspect of the resin particles according to the present invention, the particle diameter is 0.1 μm or more and 1000 μm or less.

In a specific aspect of the resin particles according to the present invention, the CV value of particle diameter is 10% or less.

In a specific aspect of the present invention, the resin particles have a BET specific surface area of 0.5 m ² /g or more and 10.0 m ² /g or less.

In a specific aspect of the resin particles according to the present invention, the resin particles are used as spacers for liquid crystal display elements, used as adhesives for electronic parts, or used to obtain conductive particles having a conductive portion. used for

According to a broad aspect of the present invention, there is provided a conductive particle comprising the resin particle described above and a conductive portion arranged on the surface of the resin particle.

In a specific aspect of the conductive particles according to the present invention, the conductive particles further include an insulating substance arranged on the outer surface of the conductive portion.

In a specific aspect of the conductive particles according to the present invention, the conductive particles have projections on the outer surface of the conductive portion.

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

According to a broad aspect of the present invention, a first member to be connected, a second member to be connected, and a connecting portion connecting the first member to be connected and the second member to be connected are connected. A connection structure is provided, wherein the connection portion includes the resin particles described above.

In a specific aspect of the connected structure according to the present invention, the first member to be connected has a first electrode on its surface, the second member to be connected has a second electrode on its surface, The connecting portion includes conductive particles, the conductive particles include the resin particles, and a conductive portion disposed on the surface of the resin particles, and the first electrode and the second electrode are connected. They are electrically connected by the conductive particles.

The resin particles according to the present invention have a coefficient of linear thermal expansion of 300 ppm/° C. or less at 100° C. to 200° C., and a compression modulus of 100 N/mm ² or more and 5000 N/mm ² or less when compressed by 10%. , a compression elastic modulus of 100 N/mm ² or more and 2000 N/mm ² or less when compressed by 30%. Since the resin particles according to the present invention have the above configuration, when used as a spacer, it is possible to effectively control the gap and prevent damage to the members to be connected even in a high-temperature environment. can. In addition, since the resin particles according to the present invention are provided with the above configuration, it is possible to suppress the occurrence of cracks in the obtained conductive particles even in a high-temperature environment. Furthermore, since the resin particles according to the present invention have the above configuration, it is possible to suppress the generation of voids in the resulting bonded structure even in a high-temperature environment.

FIG. 1 is a cross-sectional view showing resin particles according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. FIG. 5 is a cross-sectional view showing an example of a connection structure using conductive particles according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view showing an example of a connection structure using resin particles according to the first embodiment of the present invention.

The details of the present invention are described below.

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

The resin particles 1 are spherical particles. Resin particles 1 have a linear thermal expansion coefficient of 300 ppm/° C. or less at 100° C. to 200° C., and a compressive elastic modulus of 100 N/mm ² or more and 5000 N/mm ² or less when compressed by 10%, and 30%. Compressive elastic modulus when compressed is 100 N/mm ² or more and 2000 N/mm ² or less.

Like Resin Particle 1, the resin particles according to the present invention have a coefficient of linear thermal expansion of 300 ppm/° C. or less at 100° C. to 200° C., and a compressive elastic modulus of 100 N/mm ² or more when compressed by 10%. 5000 N/mm ² or less, and a compression elastic modulus when compressed by 30% is 100 N/mm ² or more and 2000 N/mm ² or less.

Conventional resin particles tend to expand due to heat, so when used as a spacer in a high temperature environment (for example, 100° C. to 200° C.), it is difficult to control the gap uniformly and constantly. It may damage the connection target member such as. In addition, in the conductive particles and the connection structure produced using the resin particles, the resin particles easily expand due to heat, so when used in a high temperature environment, the conductive particles (especially the conductive portion) Cracks may occur, and voids (bubbles) may occur around the conductive particles in the connection structure. As a result, the connection reliability of the connection structure may be lowered.

Since the resin particles according to the present invention have the above configuration, when used as spacers, they are less likely to break between members to be connected during mounting. As a result, it is possible to effectively control the gap even in a high-temperature environment, and to prevent damage to the members to be connected even in a high-temperature environment.

In addition, in the conductive particles obtained using the resin particles, the conductive material containing the conductive particles, and the connection structure containing the resin particles or the conductive particles, in a high temperature environment (for example, 100 ° C. to 200 °C), it is possible to suppress the occurrence of cracks in the conductive particles (especially the conductive portion) and the occurrence of voids in the connection structure. As a result, the connection reliability of the connection structure can be enhanced.

The resin particles have a linear thermal expansion coefficient of 300 ppm/°C or less at 100°C to 200°C. The linear thermal expansion coefficient of the resin particles at 100 to 200°C is preferably 250 ppm/°C or less, more preferably 150 ppm/°C or less, even more preferably 100 ppm/°C or less, and particularly preferably 90 ppm/°C or less. When the coefficient of linear thermal expansion of the resin particles at 100° C. to 200° C. is equal to or less than the above upper limit, the effects of the present invention can be exhibited more effectively. In addition, it is possible to more effectively suppress the occurrence of cracks in the conductive particles (particularly, the conductive portion) obtained by using the resin particles and the occurrence of voids in the connection structure.

The lower limit of the coefficient of linear thermal expansion at 100° C. to 200° C. of the resin particles is not particularly limited. A coefficient of linear thermal expansion of the resin particles at 100° C. to 200° C. may be 0 ppm/° C. or more. The reason why the temperature range for measuring the coefficient of linear thermal expansion is 100° C. to 200° C. is that the range is set based on the temperature range assumed when the conductive particles and the connecting structure are used.

The coefficient of linear thermal expansion is measured on a pellet-shaped sample prepared by compressing resin particles, using a tableting machine, by a compression load method (TMA) at a heating rate of 5° C./min. As a measuring instrument for measuring the linear thermal expansion coefficient, Seiko Instruments Inc. and "TMA Q400" manufactured by K.K. Examples of the tableting machine include "STJ-0129-1" manufactured by Taiyo Co., Ltd., and the like.

The compression elastic modulus (10% K value) when the resin particles are compressed by 10% is 100 N/mm ² or more and 5000 N/mm ² or less. The 10% K value is preferably 500 N/mm ² or more, more preferably 1000 N/mm ² or more, still more preferably 2000 N/mm ² or more, preferably 4400 N/mm ² or less, more preferably 4000 N/mm ² 3000 N/mm 2 or less, more preferably 3000 N/mm ² or less. When the 10% K value is equal to or more than the lower limit and equal to or less than the upper limit, the effects of the present invention can be exhibited more effectively.

The compression elastic modulus (30% K value) when the resin particles are compressed by 30% is 100 N/mm ² or more and 2000 N/mm ² or less. The 30% K value is preferably 300 N/mm ² or more, more preferably 500 N/mm ² or more, still more preferably 1000 N/mm ² or more, preferably 1900 N/mm ² or less, more preferably 1800 N/mm ² 1500 N/mm 2 or less, more preferably 1500 N/mm ² or less. When the 30% K value is equal to or more than the lower limit and equal to or less than the upper limit, the effects of the present invention can be exhibited more effectively.

The ratio (10% K value/30% K value) of the compression modulus (10% K value) when the resin particles are compressed by 10% to the compression modulus (30% K value) when the resin particles are compressed by 30% is , preferably 1.5 or more, more preferably 1.8 or more, still more preferably 2.0 or more, preferably 3.0 or less, more preferably 2.8 or less, further preferably 2.6 or less . When the ratio (10% K value/30% K value) is equal to or greater than the lower limit and equal to or less than the upper limit, the effects of the present invention can be exhibited more effectively.

The compression elastic modulus (10% K value and 30% K value) of the resin particles can be measured as follows.

Using a microcompression tester, a single resin particle is compressed with a cylindrical (50 μm diameter, diamond-made) smooth indenter end surface under conditions of 25° C., a compression rate of 0.3 mN/sec, and a maximum test load of 20 mN. The load value (N) and compression displacement (mm) at this time are measured. From the obtained measured values, the compression elastic moduli (10% K value and 30% K value) can be obtained by the following formula. As the microcompression tester, for example, "Fischer Scope H-100" manufactured by Fisher Co., Ltd. is used. The compression elastic moduli (10% K value and 30% K value) of the resin particles are the arithmetic mean of the compression elastic moduli (10% K value and 30% K value) of 50 arbitrarily selected resin particles. It is preferable to calculate by

10% K value and 30% K value (N/mm ² ) = (3/2 ^1/2 ) F S ^-3/2 R ^-1/2
F: Load value (N) when the resin particles are compressed and deformed by 10% or 30%
S: Compressive displacement (mm) when the resin particles are compressed and deformed by 10% or 30%
R: radius of resin particles (mm)

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

The compression recovery rate of the resin particles is preferably 5% or more, more preferably 8% or more, and preferably 60% or less, more preferably 40% or less. When the compression recovery rate is equal to or higher than the lower limit and equal to or lower than the upper limit, the effects of the present invention can be exhibited more effectively.

The compression recovery rate of the resin particles can be measured as follows.

Sprinkle resin particles on the sample stage. Using a microcompression tester, a single resin particle that has been dispersed is subjected to compression deformation of 30% in the direction of the center of the resin particle at 25° C. with a smooth indenter end face of a cylinder (50 μm in diameter, made of diamond). Apply a load (reverse load value) until After that, unloading is performed to the origin load value (0.40 mN). By measuring the load-compression displacement during this period, the compression recovery rate can be obtained from the following formula. Note that the load speed is 0.33 mN/sec. As the microcompression tester, for example, "Fischer Scope H-100" manufactured by Fisher Co., Ltd. is used.

Compression recovery rate (%) = [L2/L1] x 100
L1: Compressive displacement from the origin load value to the reverse load value when the load is applied L2: Unloading displacement from the reverse load value to the origin load value when releasing the load

The thermal decomposition temperature of the resin particles is preferably 300° C. or higher, more preferably 400° C. or higher, even more preferably 450° C. or higher, and particularly preferably 470° C. or higher. When the thermal decomposition temperature of the resin particles is equal to or higher than the lower limit, the effects of the present invention can be exhibited more effectively. In addition, it is possible to more effectively suppress the occurrence of cracks in the conductive particles (particularly, the conductive portion) obtained by using the resin particles and the occurrence of voids in the connection structure. The upper limit of the thermal decomposition temperature of the resin particles is not particularly limited. The thermal decomposition temperature of the resin particles may be 600° C. or lower.

The thermal decomposition temperature can be measured using a simultaneous differential thermogravimetric measurement device (for example, "TG/DTA: STA7200" manufactured by Hitachi High-Tech Science Co., Ltd.). The temperature at which the weight decreases by 10% from the initial weight in the measurement result is defined as the thermal decomposition temperature.

From the viewpoint of effectively controlling the gap even in a high-temperature environment when used as a spacer, the aspect ratio of the resin particles is preferably 1.0 or more, more preferably more than 1.0, and preferably 1.0. 0.5 or less, more preferably 1.3 or less, and still more preferably 1.1 or less. The aspect ratio of the resin particles indicates major axis/minor axis. For the aspect ratio of the resin particles, 50 arbitrary resin particles are observed with an electron microscope or an optical microscope, the maximum diameter and the minimum diameter are defined as the major diameter and the minor diameter, respectively, and the average value of the major diameter / minor diameter of each resin particle is calculated. It is preferable to obtain by calculating. The aspect ratio is preferably an average aspect ratio.

The particle diameter of the resin particles can be appropriately set according to the application. The particle diameter of the resin particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 50 μm or less, particularly preferably 20 μm or less, and most preferably 20 μm or less. is 10 μm or less. When the particle diameter of the resin particles is at least the lower limit and at most the upper limit, the resin particles can be more preferably used for the conductive particles and spacers.

The particle size of the resin particles is preferably an average particle size, more preferably a number average particle size. The particle diameter of the resin particles can be obtained, for example, by observing 50 arbitrary resin particles with an electron microscope or an optical microscope and calculating the average value of the particle diameter of each resin particle, or by using a particle size distribution measuring device. be done. In observation with an electron microscope or an optical microscope, the particle diameter of one resin particle is obtained as the particle diameter in the equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle size of arbitrary 50 resin particles in the equivalent circle diameter is approximately equal to the average particle size in the equivalent sphere diameter. In the particle size distribution analyzer, the particle size of one resin particle is determined as the particle size in terms of equivalent sphere diameter. The average particle size of the resin particles is preferably calculated using a particle size distribution analyzer.

In addition, in the case of measuring the particle diameter of the resin particles of the conductive particles, the measurement can be performed, for example, as follows.

The content of the conductive particles is added to "Technovit 4000" manufactured by Kulzer Co., Ltd. and dispersed to prepare an embedded resin body for conductive particle inspection. Using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation), a cross section of the conductive particles is cut out so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin body for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 25000 times, randomly select 50 conductive particles, and observe the resin particles of each conductive particle. . The particle diameter of the resin particles in each conductive particle is measured, and the arithmetic mean is taken as the particle diameter of the resin particles.

The coefficient of variation (CV value) of the particle size of the resin particles is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. When the CV value is equal to or less than the upper limit, the resin particles can be more preferably used for conductive particles and spacers.

The CV value is represented by the following formula.

CV value (%) = (ρ/Dn) × 100
ρ: standard deviation of particle size of resin particles Dn: average value of particle size of resin particles

The shape of the resin particles is not particularly limited. The shape of the resin particles may be spherical, may be other than spherical, or may be flat.

The BET specific surface area of the resin particles is preferably 0.5 m ² /g or more, more preferably 1.0 m ² /g or more, still more preferably 1.5 m ² /g or more, and preferably 10.0 m ² /g. g or less, more preferably 8.0 m ² /g or less, and even more preferably 5.0 m ² /g or less. When the BET specific surface area of the resin particles is equal to or more than the lower limit and equal to or less than the upper limit, the resin particles are less likely to break between connection target members during mounting. As a result, the gap can be effectively controlled even in a high temperature environment.

The BET specific surface area of the resin particles can be measured from a nitrogen adsorption isotherm according to the BET method. Examples of the apparatus for measuring the BET specific surface area of the resin particles include "NOVA4200e" manufactured by Quantachrome Instruments.

Applications of the resin particles are not particularly limited. The resin particles are suitably used for various purposes. By changing the compression conditions of the resin particles during use, the thickness of the resin particles can be suitably changed.

The resin particles are preferably used as spacers, as adhesives for electronic components, as conductive particles having a conductive portion, or as materials for layered manufacturing. More preferably, the resin particles are used as spacers, as adhesives for electronic parts, or as conductive particles having a conductive portion. More preferably, the resin particles are used as spacers, as adhesives for electronic parts, or to obtain conductive particles having a conductive portion. In the conductive particles, the conductive portion is formed on the surface of the resin particles.

The resin particles are preferably used for spacers or used as spacers. Examples of the method of using the above spacers include spacers for liquid crystal display elements, spacers for gap control, spacers for stress relaxation, and spacers for light modulating laminate. The gap control spacer is used for gap control of laminated chips to ensure the standoff height and flatness, and gap control of optical components to ensure the smoothness of the glass surface and the thickness of the adhesive layer. can be used. The stress relieving spacer can be used for relieving the stress of the sensor chip and the like, and relieving the stress of the connecting portion connecting the two members to be connected. Examples of the sensor chip include a semiconductor sensor chip.

The resin particles are preferably used as spacers for liquid crystal display elements, or preferably used as spacers for liquid crystal display elements, and preferably used as peripheral sealing agents for liquid crystal display elements. The resin particles are preferably used as spacers for liquid crystal displays, used as adhesives for electronic parts, or used to obtain conductive particles having a conductive portion. In the liquid crystal display element peripheral sealant, the resin particles preferably function as spacers. Since the resin particles have good compressive deformation characteristics, the resin particles are used as spacers to be arranged between substrates, or a conductive portion is formed on the surface and used as conductive particles to electrically connect electrodes. Spacers or conductive particles are effectively placed between the substrates or between the electrodes. Furthermore, since the resin particles can suppress the agglomeration and movement of the spacers, connection defects and display defects are caused in the liquid crystal display element using the spacers for a liquid crystal display element and the connection structure using the conductive particles. becomes difficult to occur.

The resin particles are preferably used in an adhesive for electronic parts or used as an adhesive for electronic parts. Examples of the adhesives for electronic components include adhesives for liquid crystal panels, adhesives for laminated substrates, adhesives for substrate circuits, and adhesives for camera modules. Examples of the laminated substrate include a semiconductor sensor chip. The resin particles used in the adhesive for electronic parts or the resin particles used as the adhesive for electronic parts are preferably adhesive resin particles having adhesive properties. When the resin particles are adhesive resin particles, the resin particles and the member to be laminated can be satisfactorily adhered when the resin particles are cured by pressure bonding. The resin particles can be used alone as an adhesive for electronic parts. The resin particles can be used as an adhesive for electronic parts without using other adhesive components. When the resin particles are used as an adhesive for electronic parts, they may not be used alone as an adhesive for electronic parts, and may be used together with other adhesive components. Moreover, when the resin particles are adhesive resin particles having adhesive properties, they can also be used as spacers and adhesives for electronic parts. When the resin particles are used as spacers and adhesives for electronic components, the physical properties required for the spacers, such as gap controllability and stress relaxation, and The coexistence with adhesiveness can be realized at a higher level.

The resin particles are preferably used as a material for layered manufacturing. When the resin particles are used as the material for layered manufacturing, for example, a three-dimensional modeled object can be formed by layering the resin particles three-dimensionally to form a specific shape, followed by curing.

Other details of the resin particles will be described below. In the present specification, "(meth)acrylate" means one or both of "acrylate" and "methacrylate", and "(meth)acrylic" means one or both of "acrylic" and "methacrylic". means.

(other details of resin particles)
The material of the resin particles is not particularly limited. The material of the resin particles is preferably an organic material. The resin particles may be particles having a porous structure or particles having a solid structure. The porous structure means a structure having a plurality of pores. The solid structure means a structure without a plurality of pores.

Examples of the organic material include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonates, polyamides, phenol formaldehyde resins, and melamine. Formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, urethane resin, isocyanate resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal , polyimide, polyamideimide, polyetheretherketone, polyethersulfone, and divinylbenzene polymer. The divinylbenzene polymer may be a divinylbenzene copolymer. Examples of the divinylbenzene copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer.

Materials for the resin particles include epoxy resins, melamine resins, benzoguanamine resins, urethane resins, isocyanate resins, polyimide resins, polyamide resins, polyamideimide resins, phenol resins, or polymerizable monomers having an ethylenically unsaturated group. It is preferably a polymer obtained by polymerizing seeds or two or more. The material of the resin particles is an epoxy resin, a melamine resin, a benzoguanamine resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a phenol resin, or one or more polymerizable monomers having an ethylenically unsaturated group. It is more preferred that the polymer is a From the viewpoint of easily obtaining resin particles having the properties of the present invention, the material of the resin particles is more preferably a polyimide resin. When the material of the resin particles satisfies the above preferable aspects, the CV value of the resin particles can be lowered, and the gap controllability can be further improved. Moreover, the connection reliability of the obtained connection structure can be further improved.

From the viewpoint of easily obtaining the resin particles having the characteristics of the present invention, it is particularly preferable that the material of the resin particles is a polymer having an imide group formed by polymerization of two or more polymerizable monomers. . The polymer having an imide group formed by polymerization of the two or more polymerizable monomers includes a polymerizable monomer having two acid anhydride groups and a polymerizable monomer having two amino groups. It is most preferably a polymer with The polymerizable monomer having the two acid anhydrides may be an esterified derivative of the polymerizable monomer having the two acid anhydrides, and the polymerizable monomer having the two acid anhydrides may be a carboxylic acid derivative. When the material of the resin particles satisfies the above preferable aspects, the CV value of the resin particles can be lowered, and the gap controllability can be further improved. Moreover, the connection reliability of the obtained connection structure can be further improved.

Examples of the polymerizable monomer having two acid anhydride groups include 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, pyromellitic anhydride, and 3,3′,4,4′-benzophenone. Tetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 9,9-bis(3,4- dicarboxyphenyl)fluorene dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5- Cyclohexanetetracarboxylic dianhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetra Carboxylic acid dianhydrides, ethylenediaminetetraacetic acid dianhydrides, esterified derivatives thereof, carboxylic acid derivatives, and the like. From the viewpoint of lowering the CV value of the particle diameter of the resin particles and further enhancing the gap controllability, the polymerizable monomer having two acid anhydride groups is 4,4′-(hexafluoroisopropylidene)diphthal Acid anhydrides or their esterified derivatives as well as carboxylic acid derivatives are preferred.

Examples of the polymerizable monomer having two amino groups include 4,4′-diaminodiphenyl ether, 1,3-phenylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,8-diaminooctane, 1, 6-diaminohexane, 1,4-diaminobutane, 1,2-diaminoethane, 1,2-bis(2-aminoethoxy)ethane and the like. From the viewpoint of lowering the CV value of the resin particles and further improving the gap controllability, the polymerizable monomer having two amino groups is preferably 4,4'-diaminodiphenyl ether.

From the viewpoint of increasing the thermal decomposition temperature and more effectively exhibiting the effects of the present invention, the presence of The total molecular weight of the imide groups (hereinafter sometimes referred to as "imide group content") is preferably 10% or more, more preferably 20% or more, and still more preferably 25% or more. When the imide group content is at least the lower limit, the effect of the present invention can be exhibited more effectively.

The resin particles can be obtained by polymerizing a polymerizable monomer having an imide group in the main chain. The polymerization method is not particularly limited, and includes known methods such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, polycondensation), addition condensation, living polymerization, and living radical polymerization. Other polymerization methods include suspension polymerization in the presence of a radical polymerization initiator.

(Conductive particles)
The conductive particles include the resin particles described above and a conductive portion arranged on the surface of the resin particles.

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

A conductive particle 11 shown in FIG. 2 has a resin particle 1 and a conductive portion 2 arranged on the surface of the resin particle 1 . The conductive portion 2 covers the surfaces of the resin particles 1 . The conductive particles 11 are coated particles in which the surfaces of the resin particles 1 are coated with the conductive portions 2 .

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

A conductive particle 21 shown in FIG. 3 has a resin particle 1 and a conductive portion 22 arranged on the surface of the resin particle 1 . The conductive particles 21 shown in FIG. 3 differ from the conductive particles 11 shown in FIG. 2 only in the conductive portions 22 . The conductive portion 22 has a first conductive portion 22A that is an inner layer and a second conductive portion 22B that is an outer layer. A first conductive portion 22A is arranged on the surface of the resin particle 1 . A second conductive portion 22B is arranged on the surface of the first conductive portion 22A.

FIG. 4 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

A conductive particle 31 shown in FIG. 4 has a resin particle 1 , a conductive portion 32 , a plurality of core substances 33 , and a plurality of insulating substances 34 .

The conductive portion 32 is arranged on the surface of the resin particle 1 . The conductive particles 31 have a plurality of projections 31a on their surfaces. The conductive portion 32 has a plurality of projections 32a on its outer surface. Thus, the conductive particles may have projections on the surface, or may have projections on the outer surface of the conductive portion. A plurality of core substances 33 are arranged on the surface of the resin particles 1 . A plurality of core substances 33 are embedded in the conductive portion 32 . The core substance 33 is arranged inside the protrusions 31a and 32a. The conductive portion 32 covers a plurality of core substances 33 . The outer surface of the conductive portion 32 is raised by a plurality of core substances 33 to form protrusions 31a and 32a.

The conductive particles 31 have an insulating material 34 disposed on the outer surface of the conductive portion 32 . At least a partial region of the outer surface of the conductive portion 32 is covered with an insulating material 34 . The insulating substance 34 is made of an insulating material and is an insulating particle. Thus, the conductive particles may have an insulating material disposed on the outer surface of the conductive portion.

The metal for forming the conductive portion is not particularly limited. The above metals 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. Further, examples of the metal include tin-doped indium oxide (ITO) and solder. From the viewpoint of further increasing the connection reliability between the electrodes, the metal is preferably an alloy containing tin, nickel, palladium, copper or gold, preferably nickel or palladium.

Like the conductive particles 11 and 31, the conductive portion may be formed of one layer. Like the conductive particles 21, the conductive portion may be formed of multiple layers. That is, the conductive portion may have a laminated structure of two or more layers. When the conductive portion 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, and is a gold layer. is more preferred. When the outermost layer is one of these preferred conductive parts, the connection reliability between the electrodes can be further enhanced. Moreover, when the outermost layer is a gold layer, the corrosion resistance can be further enhanced.

The method of forming the conductive portion on the surface of the resin particles is not particularly limited. Examples of the method for forming the conductive portion include a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a method of coating the surface of resin particles with a metal powder or a paste containing a metal powder and a binder. mentioned. From the viewpoint of forming the conductive portion more easily, the method of forming the conductive portion is preferably a method using electroless plating. Methods such as vacuum deposition, ion plating, and ion sputtering can be used as the method by physical vapor deposition.

The compression elastic modulus (10% K value) when the conductive particles are compressed by 10% is preferably 180 N/mm ² or more, more preferably 1800 N/mm ² or more, and still more preferably 3600 N/mm ² or more, It is preferably 9000 N/mm ² or less, more preferably 7000 N/mm ² or less, still more preferably 5000 N/mm ² or less. When the 10% K value is equal to or more than the lower limit and equal to or less than the upper limit, the effects of the present invention can be exhibited more effectively.

The compression elastic modulus (30% K value) when the conductive particles are compressed by 30% is preferably 180 N/mm ² or more, more preferably 900 N/mm ² or more, and still more preferably 1800 N/mm ² or more, It is preferably 3600 N/mm ² or less, more preferably 3000 N/mm ² or less, still more preferably 2500 N/mm ² or less. When the 30% K value is equal to or more than the lower limit and equal to or less than the upper limit, the effects of the present invention can be exhibited more effectively.

The compressive elastic modulus (10% K value and 30% K value) of the conductive particles can be measured in the same manner as the compressive elastic modulus (10% K value and 30% K value) of the resin particles.

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

The compression recovery rate of the conductive particles is preferably 5% or more, more preferably 8% or more, and preferably 60% or less, more preferably 40% or less. When the compression recovery rate is equal to or higher than the lower limit and equal to or lower than the upper limit, the effects of the present invention can be exhibited more effectively.

The compression recovery rate of the conductive particles can be measured in the same manner as the compression recovery rate of the resin particles.

The particle diameter of the conductive particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1.0 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 100 μm. Below, more preferably 50 μm or less, particularly preferably 20 μm or less. When the particle size of the conductive particles is at least the lower limit and at most the upper limit, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, and the conductive It becomes difficult to form agglomerated conductive particles when forming the part. Also, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portions are less likely to separate from the surface of the resin particles. Moreover, when the particle size of the conductive particles is equal to or more than the lower limit and equal to or less than the upper limit, the conductive particles can be suitably used as a conductive material.

The particle diameter of the conductive particles means the diameter when the conductive particles are spherical, and when the conductive particles have a shape other than a spherical shape, it is assumed to be a true sphere corresponding to the volume. means the diameter of

The particle size of the conductive particles is preferably an average particle size, more preferably a number average particle size. The particle size of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average value, or by performing laser diffraction particle size distribution measurement. In observation with an electron microscope or an optical microscope, the particle size of each conductive particle is obtained as the particle size in circle equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle size of arbitrary 50 conductive particles in equivalent circle diameter is almost equal to the average particle size in equivalent sphere diameter. In the laser diffraction particle size distribution measurement, the particle size of each conductive particle is obtained as the particle size in terms of equivalent sphere diameter. The particle size of the conductive particles is preferably calculated by laser diffraction particle size distribution measurement.

The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive portion when the conductive portion has multiple layers. When the thickness of the conductive portion is the above lower limit or more and the above upper limit or less, sufficient conductivity is obtained, and the conductive particles do not become too hard, and the conductive particles are sufficiently deformed when connecting between electrodes. do.

When the conductive portion is formed of a plurality of layers, the thickness of the conductive portion in the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, and more preferably. is 0.1 μm or less. When the thickness of the conductive portion of the outermost layer is equal to or more than the lower limit and equal to or less than the upper limit, the coating with the conductive portion of the outermost layer is uniform, the corrosion resistance is sufficiently high, and the connection reliability between the electrodes is improved. can be further enhanced. Further, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

The thickness of the conductive portion can be measured by observing the cross section of the conductive particles using, for example, a transmission electron microscope (TEM). Regarding the thickness of the conductive portion, it is preferable to calculate the average value of the thickness of the conductive portion at five locations as the thickness of the conductive portion of one conductive particle, and the average value of the thickness of the entire conductive portion. More preferably, it is calculated as the thickness of the conductive portion of the conductive particles. The thickness of the conductive portion is preferably obtained by calculating the average value of the thickness of the conductive portion of each conductive particle for 50 arbitrary conductive particles. The thickness of the conductive portion is preferably an average thickness.

The conductive particles preferably have protrusions on the outer surface of the conductive portion. The conductive particles preferably have protrusions on their surfaces. It is preferable that there are a plurality of protrusions. An oxide film is often formed on the surface of the conductive part and the surface of the electrode connected by the conductive particles. When conductive particles having projections are used, the oxide film is effectively removed by the projections by arranging the conductive particles between the electrodes and pressing them. Therefore, the electrodes and the conductive portions of the conductive particles can be brought into contact with each other more reliably, and the connection resistance between the electrodes can be further reduced. Furthermore, when the conductive particles are provided with an insulating substance on the surface, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusions of the conductive particles may cause the conductive particles and the electrode to contact each other. It is possible to more effectively eliminate the insulating material or the binder resin between them. Therefore, it is possible to further improve the connection reliability between the electrodes.

As a method for forming protrusions on the surface of the conductive particles, a method of forming a conductive part by electroless plating after attaching a core substance to the surface of the resin particle, and a method of forming a conductive part by electroless plating on the surface of the resin particle. After forming the part, a core substance is adhered, and then a conductive part is formed by electroless plating. Also, the core substance may not be used to form the projections.

As a method for forming the protrusions, the following methods may be used. A method of adding a core substance in the middle of forming a conductive portion on the surface of a resin particle by electroless plating. As a method of forming projections by electroless plating without using a core material, electroless plating generates metal nuclei, attaches the metal nuclei to the surface of resin particles or conductive parts, and forms conductive parts by electroless plating. how to.

It is preferable that the conductive particles further include an insulating material disposed on the outer surface of the conductive portion. In this case, if the conductive particles are used to connect the electrodes, short-circuiting between adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles come into contact with each other, an insulating material exists between the plurality of electrodes, so short-circuiting between horizontally adjacent electrodes can be prevented instead of between the upper and lower electrodes. . When the electrodes are connected, the insulating material between the conductive portion of the conductive particles and the electrodes can be easily eliminated by pressing the conductive particles with two electrodes. When the conductive particles have projections on the surface of the conductive portion, the insulating material between the conductive portion of the conductive particles and the electrode can be removed more easily. The insulating substance is preferably an insulating resin layer or insulating particles, more preferably insulating particles. The insulating particles are preferably insulating resin particles.

The outer surface of the conductive part and the surface of the insulating particles may each be coated with a compound having a reactive functional group. The outer surface of the conductive portion and the surface of the insulating particles may not be directly chemically bonded, or may be indirectly chemically bonded by a compound having a reactive functional group. After introducing carboxyl groups to the outer surface of the conductive portion, the carboxyl groups may be chemically bonded to functional groups on the surface of the insulating particles via a polymer electrolyte such as polyethyleneimine.

(Conductive material)
The conductive material includes the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is suitably used for electrical connection of electrodes. The conductive material is preferably a circuit connecting material.

The binder resin is not particularly limited. A known insulating resin is used as the binder resin. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include photocurable components and thermosetting components. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers and elastomers. Only one type of the binder resin may be used, or two or more types may be used in combination.

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

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a coloring agent, an antioxidant, a heat stabilizer, and a light stabilizer. It may contain various additives such as agents, UV absorbers, lubricants, antistatic agents and flame retardants.

The method for dispersing the conductive particles in the binder resin is not particularly limited, and 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. A method of adding the conductive particles to the binder resin and then kneading and dispersing the mixture with 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, then added to the binder resin, kneaded with a planetary mixer or the like, and dispersed. A method of diluting the binder resin with water, an organic solvent, or the like, adding the conductive particles, and kneading and dispersing the mixture with a planetary mixer or the like.

The viscosity (η25) of the conductive material at 25° C. is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, and preferably 400 Pa·s or less, more preferably 300 Pa·s or less. When the viscosity at 25° C. of the conductive material is equal to or higher than the lower limit and equal to or lower than the upper limit, the connection reliability between the electrodes can be enhanced more effectively. The viscosity (η25) can be appropriately adjusted depending on the types and amounts of ingredients to be blended.

The viscosity (η25) can be measured at 25° C. and 5 rpm using, for example, an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.).

The conductive material can be used as a conductive paste, a conductive film, and the like. When the conductive material according to the present invention is a conductive film, a film containing no conductive particles may be laminated on a 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% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, and particularly preferably 70% by weight or more. is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is at least the lower limit and at most the upper limit, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material is further increased.

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 80% by weight or less, more preferably 60% by weight. %, more preferably 40% by weight or less, more preferably 20% by weight or less, and particularly preferably 10% by weight or less. When the content of the conductive particles is at least the lower limit and at most the upper limit, the connection resistance between the electrodes can be more effectively reduced, and the connection reliability between the electrodes can be more effectively improved. can be enhanced.

(connection structure)
A connection structure can be obtained by connecting the members to be connected using the resin particles described above.

The connection structure using the resin particles connects a first member to be connected, a second member to be connected, and the first member to be connected and the second member to be connected. and a part. In the connection structure, the connection portion contains the resin particles. In the connection structure, the connection portion is preferably formed of the resin particles, or formed of a composition containing the resin particles.

Further, a connection structure can be obtained by connecting members to be connected using the above-described conductive particles or a conductive material containing the above-described conductive particles and a binder resin.

The connection structure using the conductive particles includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, and the first connection A connecting portion connecting the target member and the second connection target member. In the connection structure, the connection portion contains conductive particles. In the connection structure, it is preferable that the connection portion is formed of conductive particles, or formed of a conductive material containing the conductive particles and a binder resin. The conductive particles include the resin particles described above and a conductive portion arranged on the surface of the resin particles. In the connection structure, the first electrode and the second electrode are electrically connected by the conductive particles.

When the conductive particles are used alone, the connecting part itself is the conductive particles. That is, the first member to be connected and the second member to be connected are connected by the conductive particles. The conductive material used to obtain the connection structure is preferably an anisotropic conductive material.

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

A connection structure 41 shown in FIG. 5 is a connection structure that connects a first connection target member 42 , a second connection target member 43 , and the first connection target member 42 and the second connection target member 43 . a portion 44; The connecting portion 44 is made of a conductive material containing the conductive particles 11 and a binder resin. In FIG. 5, 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 and 31 may be used.

The first connection target member 42 has a plurality of first electrodes 42a on its surface (upper surface). The second connection target member 43 has a plurality of second electrodes 43a on its surface (lower surface). The first electrode 42 a and the second electrode 43 a are electrically connected by one or more conductive particles 11 . Therefore, the first and second connection object members 42 and 43 are electrically connected by the conductive particles 11 .

The manufacturing method of the connection structure is not particularly limited. As an example of a method for manufacturing a connected structure, the conductive material is arranged between a first member to be connected and a second member to be connected to obtain a laminate, and then the laminate is heated and pressurized. methods and the like. The pressure during pressurization is preferably 40 MPa or more, more preferably 60 MPa or more, and preferably 90 MPa or less, more preferably 70 MPa or less. The temperature during the heating is preferably 80° C. or higher, more preferably 100° C. or higher, and preferably 140° C. or lower, more preferably 120° C. or lower.

The first member to be connected and the second member to be connected are not particularly limited. Specifically, the first connection target member and the second connection target member include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, as well as resin films, printed circuit boards, flexible Examples include electronic components such as circuit boards such as printed boards, flexible flat cables, rigid flexible boards, glass epoxy boards and glass boards. The first member to be connected and the second member to be connected are preferably electronic components.

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 on the member to be connected in the paste-like state.

The conductive particles, the conductive material, and the connecting material are also suitably used for touch panels. Therefore, it is preferable that the member to be connected is a flexible substrate or a member to be connected in which electrodes are arranged on the surface of a resin film. The member to be connected is preferably a flexible substrate, and is preferably a member to be connected in which electrodes are arranged on the surface of a resin film. When the flexible substrate is a flexible printed substrate or the like, the flexible substrate generally has electrodes on its surface.

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

Moreover, the resin particles can be suitably used as spacers for liquid crystal display elements. When the resin particles are used as spacers for a liquid crystal display element, the gap can be effectively controlled and damage to the substrate can be prevented. The first member to be connected may be a first liquid crystal display element member. The second member to be connected may be a second liquid crystal display element member. The connection portion connects the first liquid crystal display element member and the second liquid crystal display element member in a state in which the first liquid crystal display element member and the second liquid crystal display element member are opposed to each other. It may be a seal portion that seals the outer periphery of the .

The resin particles can also be used as a peripheral sealant for liquid crystal display elements. The liquid crystal display element includes a first liquid crystal display element member and a second liquid crystal display element member. The liquid crystal display element comprises the first liquid crystal display element member and the second liquid crystal display element member in a state in which the first liquid crystal display element member and the second liquid crystal display element member face each other. and a liquid crystal disposed between the first liquid crystal display element member and the second liquid crystal display element member inside the seal portion. Prepare. In this liquid crystal display element, the liquid crystal dropping method is applied, and the sealing portion is formed by thermally curing a sealing agent for the liquid crystal dropping method.

FIG. 6 is a cross-sectional view showing an example of a connection structure using resin particles according to the first embodiment of the present invention.

A connection structure 81 shown in FIG. 6 is a liquid crystal display element. The connection structure 81 has a pair of transparent glass substrates 82 as members to be connected. The transparent glass substrate 82 has an insulating film (not shown) on the opposing surface. Examples of materials for the insulating film include SiO ₂ and the like. A transparent electrode 83 is formed on the insulating film of the transparent glass substrate 82 . Materials for the transparent electrode 83 include ITO and the like. The transparent electrode 83 can be formed by patterning by photolithography, for example. An alignment film 84 is formed on the transparent electrode 83 on the surface of the transparent glass substrate 82 . Examples of the material of the alignment film 84 include polyimide.

A liquid crystal 85 is sealed between the pair of transparent glass substrates 82 . A plurality of resin particles 1 are arranged between the pair of transparent glass substrates 82 . The resin particles 1 are used as spacers for liquid crystal display elements. The distance between the pair of transparent glass substrates 82 is regulated by the plurality of resin particles 1 . A sealant 86 is placed between the edges of the pair of transparent glass substrates 82 . The sealant 86 prevents the liquid crystal 85 from flowing out to the outside. The sealing agent 86 contains resin particles 1A that differ from the resin particles 1 only in particle size.

In the liquid crystal display element, the arrangement density of spacers for a liquid crystal display element per 1 mm ² is preferably 10/mm ² or more, and preferably 1000/mm ² or less. When the arrangement density is 10/mm ² or more, the cell gap becomes even more uniform. When the arrangement density is 1000 pieces/mm ² or less, the contrast of the liquid crystal display device becomes even better.

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

(Example 1)
(1) Preparation of Resin Particles 5.6 parts by weight of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride and 98 parts by weight of ethanol were added to a reaction vessel equipped with a thermometer, a cooling pipe, and a raw material supply port. was added and uniformly dissolved by stirring for 1 hour. Next, the mixture was stirred for 8 hours while the temperature was raised to 80° C. and the ethanol was heated to reflux, thereby obtaining an ethanol solution of the diethyl ester compound.

Next, 2.5 parts by weight of 4,4'-diaminodiphenyl ether was added to the obtained ethanol solution in a reaction vessel equipped with a thermometer, a cooling pipe, and a raw material supply port, and stirred for 1 hour to dissolve uniformly. rice field. Next, the mixture was heated to 80° C. and stirred for 5 hours while heating and refluxing ethanol. After completion of the reaction, ethanol was distilled off using an evaporator to obtain a monomer salt.

Furthermore, in a reaction vessel equipped with a thermometer, a cooling pipe, and a raw material supply port, the above monomer salt, a dispersion stabilizer (“PVP K-30” manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) 1.3 parts by weight, and a reaction solvent 296 parts by weight of ethylene glycol was added as a solvent and stirred for 1 hour to dissolve uniformly. Next, the mixture was heated to 200° C., stirred for 24 hours while heating and refluxing ethylene glycol, and then classified to obtain resin particles.

(2) Preparation of conductive particles After dispersing 10 parts by weight of the resulting resin particles in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution is filtered. The resin particles were taken out. Next, the resin particles were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surface of the resin particles. After thoroughly washing the surface-activated resin particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion. Next, 1 g of nickel particle slurry (average particle size: 100 nm) was added to the above dispersion over 3 minutes to obtain resin particles to which the core substance was attached. Suspension A was obtained by adding and dispersing the resin particles to which the core substance was attached in 500 parts by weight of distilled water.

Also, as the nickel plating solution for the first step, a mixture of 500 g/L of nickel sulfate, 150 g/L of sodium hypophosphite, 150 g/L of sodium citrate, and 6 ml/L of a plating stabilizer was adjusted to pH 8 with ammonia. A plating solution was prepared. 150 ml of this plating solution was added dropwise to Suspension A through a metering pump at an addition rate of 20 ml/min. The reaction temperature was set at 50°C. Thereafter, the mixture was stirred until the pH was stabilized, and after confirming that the bubbling of hydrogen had stopped, the electroless plating first step was carried out.

Next, as a nickel plating solution for a later process, a plating solution was prepared by adjusting a mixture of 500 g/L of nickel sulfate, 80 g/L of dimethylamine borane, and 10 g/L of sodium tungstate to pH 11 with sodium hydroxide. 350 ml of this plating solution was passed through a metering pump at an addition rate of 10 ml/min and dropped into the suspension A after the previous electroless plating step. The reaction temperature was set at 30°C. After that, the mixture was stirred until the pH was stabilized, and after confirming that the bubbling of hydrogen had stopped, the latter stage of electroless plating was carried out. After that, the suspension A is filtered to take out the particles, washed with water, and dried to have the resin particles and the nickel conductive layer (conductive portion) arranged on the surface of the resin particles, and the conductive portion Conductive particles having protrusions on their outer surfaces were obtained.

(3) Preparation of conductive material (anisotropic conductive paste) 7 parts by weight of the obtained conductive particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, and 30 parts by weight of phenol novolak type epoxy resin. A conductive material (anisotropic conductive paste) was obtained by blending parts by weight and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.), followed by defoaming and stirring for 3 minutes.

(4) Fabrication of Connection Structure A transparent PET substrate having a thickness of 0.5 mm was prepared by forming an IZO electrode pattern on the upper surface of an Al—Nd alloy wiring having an L/S ratio of 15 μm/15 μm. Also, a semiconductor chip having a gold electrode pattern with L/S of 15 μm/15 μm formed on the lower surface was prepared. The obtained anisotropic conductive paste was applied onto the transparent PET substrate so as to have a thickness of 30 μm to form an anisotropic conductive paste layer. Next, the semiconductor chip was laminated on the anisotropic conductive paste layer so that the electrodes faced each other. After that, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185° C., a pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 30 MPa per bump area is applied to achieve anisotropic conduction. The paste layer was cured at 185° C. to obtain a connection structure.

(Example 2)
Resin particles were prepared in the same manner as in Example 1, except that 1.4 parts by weight of 1,3-phenylenediamine was used instead of 2.5 parts by weight of 4,4'-diaminodiphenyl ether. Particles, conductive particles, conductive material, and connecting structures were obtained.

(Example 3)
1.8 parts by weight of 1,3-di(aminomethyl)cyclohexane (mixture of cis-type structure and trans-type structure) instead of 2.5 parts by weight of 4,4'-diaminodiphenyl ether when preparing resin particles Part was used. Also, the amount of the dispersion stabilizer added was changed from 1.3 parts by weight to 1.2 parts by weight, and the amount of the reaction solvent added was changed from 296 parts by weight to 270 parts by weight. Resin particles, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except for the above changes.

(Example 4)
1.8 parts by weight of 1,8-diaminooctane was used in place of 2.5 parts by weight of 4,4'-diaminodiphenyl ether when preparing the resin particles. Also, the amount of the dispersion stabilizer added was changed from 1.3 parts by weight to 1.2 parts by weight, and the amount of the reaction solvent added was changed from 296 parts by weight to 271 parts by weight. Resin particles, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except for the above changes.

(Comparative example 1)
Polystyrene particles having an average particle size of 0.85 μm were prepared as seed particles. 0.85 parts by weight of the polystyrene particles, 500 parts by weight of ion-exchanged water, and 120 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol were mixed to prepare a mixed solution. After the mixed liquid was dispersed by ultrasonic waves, it was placed in a separable flask and uniformly stirred.

Next, 19 parts by weight of isobornyl acrylate as a monomer, 5 parts by weight of divinylbenzene (purity 96% by weight), and 1.3 parts by weight of benzoyl peroxide ("Nyper BW" manufactured by NOF Corporation) as a polymerization initiator. , 7.4 parts by weight of triethanolamine lauryl sulfate and 22 parts by weight of ethanol were added to 350 parts by weight of ion-exchanged water to prepare an emulsion.

The emulsified liquid was added in two portions to the mixed liquid in the separable flask and stirred for 8 hours to allow the seed particles to absorb the monomer, thereby obtaining a suspension containing seed particles in which the monomer was swollen. .

Thereafter, 170 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol was added, and heating was started to react at 85° C. for 11 hours to obtain resin particles.

Conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Example 1, except that the obtained resin particles were used.

(Comparative example 2)
Resin particles, conductive We obtained a conductive particle, a conductive material, and a connection structure.

(Comparative Example 3)
19 parts by weight of isobornyl acrylate was changed to 12 parts by weight of tetraacrylate (“NK Ester A-TMMT” manufactured by Shin-Nakamura Chemical Co., Ltd.), and the amount of divinylbenzene (purity 96% by weight) added was changed from 5 parts by weight. Resin particles, conductive particles, a conductive material, and a connection structure were obtained in the same manner as in Comparative Example 1, except that the content was changed to 12 parts by weight.

(evaluation)
(1) Particle diameter (number average particle diameter) of resin particles and CV value of particle diameter of resin particles About 100,000 resin particles were measured using a particle size distribution analyzer (“Multisizer 4” manufactured by Beckman Coulter, Inc.). The particle diameters of the resin particles were measured, and the average value was calculated. Moreover, the CV value of the particle diameter of the resin particles was calculated from the following formula from the measurement result of the particle diameter of the resin particles.

CV value (%) = (ρ/Dn) × 100
ρ: standard deviation of particle diameter of resin particles Dn: average particle diameter of resin particles

(2) Aspect ratio of resin particles The obtained resin particles were observed with a scanning electron microscope to determine the aspect ratio. As the aspect ratio, the average value of the aspect ratios of 50 arbitrary resin particles was adopted.

(3) BET Specific Surface Area The BET specific surface area of the obtained resin particles was measured from the adsorption isotherm of nitrogen according to the BET method using a measuring device ("NOVA4200e" manufactured by Quantachrome Instruments).

(4) Coefficient of linear thermal expansion A plate-shaped sample having the same composition as the obtained resin particles was prepared, and the temperature was increased by a compressive load method (TMA) using a measuring instrument (“TMA Q400” manufactured by Seiko Instruments Inc.). The linear thermal expansion coefficient was measured at a rate of 5°C/min.

(5) Thermal decomposition temperature The thermal decomposition temperature of the obtained resin particles was measured using a simultaneous differential thermogravimetric analyzer (“TG/DTA: STA7200” manufactured by Hitachi High-Tech Science). The thermal decomposition temperature is the temperature at which the weight decreases by 10% from the initial weight in the measurement results.

(6) 10% K value, 30% K value and ratio (10% K value/30% K value) of resin particles
The compression elastic modulus (10% K value) when the obtained resin particles were compressed by 10% and the compression elastic modulus (30% K value) when compressed by 30% were measured by the method described above. Also, a ratio (10% K value/30% K value) was determined by calculation. As a microcompression tester, "Fischer Scope H-100" manufactured by Fisher Co. was used.

(7) Gap Controllability The obtained connected structure was heated to 200° C. in an oven and left for 1 hour while maintaining the temperature. Observation was made with a scanning electron microscope (SEM), and the minimum thickness and maximum thickness of the connection portion (anisotropic conductive paste layer) were measured. Gap controllability was judged according to the following criteria.

[Criteria for determining gap controllability]
○: The maximum thickness is less than 1.2 times the minimum thickness △: The maximum thickness is 1.2 times or more and less than 1.4 times the minimum thickness ×: The maximum thickness is 1.4 times or more the minimum thickness

(8) Damage prevention property of member to be connected For the connection structure evaluated in (7), the number of damages per 1 mm x 1 mm on the PET substrate surface was measured using an optical microscope. The damage prevention property of the member to be connected was judged according to the following criteria.

[Determination Criteria for Damage Prevention of Connection Object Member]
○: The number of damages on the PET substrate surface is 0 or more and 5 or less ×: The number of damages on the PET substrate surface is 6 or more

(9) Void Suppression 100 pieces of the connection structure thus obtained were heated to 300° C. in an oven and left for 1 hour while maintaining the temperature. A cross-section of the connection portion of the connection structure after standing was cut out using a cross-section polisher ("IB-19530CP" manufactured by JEOL Ltd.). Using a field emission transmission electron microscope (FE-TEM) ("JEM-ARM200F" manufactured by JEOL Ltd.), the image magnification was set to 10000 times, and the presence or absence of voids (bubbles) around the conductive particles was observed. The void suppression property was judged according to the following criteria.

[Void suppression criteria]
〇〇: 1 or less connected structures with voids 〇: 2 to 5 connected structures with voids △: 6 or more 10 connected structures with voids ×: 11 or more connection structures with voids

(10) Crack Suppression 5 g of the obtained conductive particles were heated to 300° C. in an oven and left for 1 hour while maintaining the temperature. Using a field emission transmission electron microscope (FE-TEM) ("JEM-ARM200F" manufactured by JEOL Ltd.), the conductive particles after standing are set to an image magnification of 10000 times, and 100 conductive particles are discarded. Randomly selected samples were observed for the presence or absence of cracks in the conductive portions. Crack suppression was judged according to the following criteria.

[Criteria for Crack Suppression]
〇〇: 1 or less conductive particles with cracks 〇: 2 to 5 conductive particles with cracks △: 6 or more conductive particles with cracks 10 pcs or less ×: 11 or more conductive particles with cracks

(11) Connection reliability (between upper and lower electrodes)
The connection resistance between the upper and lower electrodes of 20 obtained connection structures was measured by the four-probe method. An average value of connection resistance was calculated. From the relationship of voltage=current×resistance, the connection resistance can be obtained by measuring the voltage when a constant current flows. Connection reliability was determined according to the following criteria.

[Connection Reliability Judgment Criteria]
○○: The average value of connection resistance is 2.0 Ω or less ○: The average value of connection resistance is over 2.0 Ω and 3.0 Ω or less ×: The average value of connection resistance is over 3.0 Ω

The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1, 1A... Resin particle 2... Conductive part 11... Conductive particle 21... Conductive particle 22... Conductive part 22A... First conductive part 22B... Second conductive part 31... Conductive particle 31a... Projection 32... Conductive part DESCRIPTION OF SYMBOLS 32a... Protrusion 33... Core substance 34... Insulating substance 41... Connection structure 42... First connection object member 42a... First electrode 43... Second connection object member 43a... Second electrode 44... Connection part 81 … Connection structure (liquid crystal display element)
82... Transparent glass substrate (member to be connected)
83... Transparent electrode 84... Alignment film 85... Liquid crystal 86... Sealant

Claims (16)

A linear thermal expansion coefficient at 100 ° C. to 200 ° C. is 300 ppm / ° C. or less,
Compressive elastic modulus when compressed by 10% is 100 N/mm ² or more and 5000 N/mm ² or less,
Resin particles having a compression elastic modulus of 100 N/mm ² or more and 2000 N/mm ² or less when compressed by 30%. 2. The resin particles according to claim 1, having a linear thermal expansion coefficient of 100 ppm/°C or less at 100°C to 200°C. 3. The resin particles according to claim 1, wherein the ratio of the compression modulus when compressed by 10% to the compression modulus when compressed by 30% is 1.5 or more and 3.0 or less. The resin particles according to any one of claims 1 to 3, which have a thermal decomposition temperature of 400°C or higher. 5. The resin particle according to any one of claims 1 to 4, wherein the resin particle material comprises a polymer having an imide group formed by polymerization of two or more polymerizable monomers. The resin particles according to any one of claims 1 to 5, which have an aspect ratio of 1.0 or more and 1.1 or less. The resin particles according to any one of claims 1 to 6, having a particle diameter of 0.1 µm or more and 1000 µm or less. The resin particles according to any one of claims 1 to 7, wherein the CV value of the particle diameter is 10% or less. The resin particles according to any one of claims 1 to 8, having a BET specific surface area of 0.5 m ² /g or more and 10.0 m ² /g or less. The resin according to any one of claims 1 to 9, which is used as a spacer for liquid crystal display elements, used as an adhesive for electronic parts, or used to obtain conductive particles having a conductive portion. particle. The resin particles according to any one of claims 1 to 10;
and a conductive portion disposed on the surface of the resin particles. 12. The conductive particle of Claim 11, further comprising an insulating material disposed on the outer surface of said conductive portion. 13. The conductive particles according to claim 11 or 12, having projections on the outer surface of said conductive portion. Containing conductive particles and a binder resin,
A conductive material, wherein the conductive particles comprise the resin particles according to any one of claims 1 to 10, and conductive portions disposed on the surfaces of the resin particles. a first connection target member;
a second connection target member;
A connecting portion connecting the first connection target member and the second connection target member,
A connection structure, wherein the connection portion contains the resin particles according to any one of claims 1 to 10. The first member to be connected has a first electrode on its surface,
The second member to be connected has a second electrode on its surface,
wherein the connecting portion contains conductive particles;
The conductive particles comprise the resin particles and a conductive portion disposed on the surface of the resin particles,
16. The connected structure according to claim 15, wherein said first electrode and said second electrode are electrically connected by said conductive particles.

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