Resin particles, conductive particles, conductive material, and connection structure

Abstract

A purpose of the present invention is to provide resin particles that have excellent resistance to heat, that, when used as base particles of electrically conductive particles, allows implementation of thermocompression bonding with a low pressure, and that can be used to obtain a connection structure having excellent connection reliability. Another purpose of the present invention is to provide: electrically conductive particles obtained by using the resin particles; an electrically conductive material; and a connection structure. The resin particles according to the present invention have a 5% weight loss temperature of 350°C or higher, a 10% K value of 100<sp / >-2500 N / mm2 at 25°C, and a 30% K value of 100<sp / >-1500 N / mm2 at 25°C.

Description

Technical Field

[0001] The present invention relates to resin particles that are excellent in heat resistance, and when used as base particles for conductive particles, can cope with thermocompression bonding mounting at low pressure and can obtain a connection structure excellent in connection reliability. The present invention also relates to conductive particles, a conductive material, and a connection structure using the resin particles.

Background Art

[0002] As a method for electrically connecting between electrodes of an electronic circuit board, etc., a method using conductive particles in which a conductive layer is formed on the surface of base particles such as resin particles has been proposed (for example, Patent Document 1). Such conductive particles are used, for example, in IC chips, liquid crystal display elements, etc.

[0003] In conventional conductive particles, when electrically connecting between electrodes at a relatively low pressure, the connection resistance between the electrodes may become high. This is because at a relatively low pressure, the conductive particles do not deform sufficiently, and it is difficult for the conductive particles and the electrodes to come into sufficient contact. Therefore, when using conventional conductive particles, a relatively high pressure is required to sufficiently deform the conductive particles.

[0004] However, when electrically connecting between electrodes at a relatively high pressure, although the base particles or the conductive particles can be deformed, scratches may be formed on the electrodes, and the connection resistance may become high. In addition, an action for the compressed base particles or conductive particles to return to their original shape may work, and a phenomenon called springback may occur. When springback occurs in the base particles or the conductive particles, the contact area between the conductive particles and the electrodes decreases, the connection resistance increases, and the connection reliability may decrease.

[0005] In recent years, various IC chips have come to be used also in the vicinity of engines such as in automobiles and motor drive units. These environments are severe environments that are affected by high temperatures over a long period of time and repeatedly, unlike the case of IC chips for conventional electronic device applications. Therefore, long-term reliability at high temperatures is required for each member constituting the IC chip, and the base particles of the conductive particles are required to have excellent heat resistance.

[0006] Also, in recent years, in liquid crystal display elements, flexible substrates are increasingly being used due to the progress of narrow bezelization and thinning. For example, in a method for manufacturing a liquid crystal display element, after disposing a conductive material containing conductive particles on a glass substrate, a flexible substrate is laminated and thermocompression bonded by a FOG method, and the flexible substrate is mounted. When thermocompression bonding is performed at a high pressure during mounting of the flexible substrate by such a FOG method, distortion may occur after mounting, and there has been a problem that display unevenness may occur in the obtained liquid crystal display element. Therefore, the base particles of the conductive particles are required to have flexibility corresponding to thermocompression bonding mounting at a low pressure.

[0007] As resin particles having excellent heat resistance, for example, divinylbenzene crosslinked particles are known. However, since these particles are hard, when used as the base particles of the conductive particles in the case of performing low-pressure mounting such as the above-mentioned FOG method, it has been difficult to cope with thermocompression bonding mounting at a low pressure. Also, polyimide particles and the like are known as resin particles having excellent heat resistance. For example, Patent Document 2 discloses a method for manufacturing polyimide particles. However, it is difficult to obtain truly spherical particles with good reproducibility for the polyimide particles that can be produced by the manufacturing method disclosed in Patent Document 2, and the plating process required when used as the base particles of the conductive particles is complicated, which has been a problem. Furthermore, Patent Document 3 also discloses a similar method for manufacturing polyimide particles, but the particle size thereof is on the order of several hundred nm, which is too small for use as the above-mentioned conductive particles.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0009]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object of the present invention is to provide resin particles that are excellent in heat resistance, can cope with thermocompression bonding mounting at a low pressure when used as base particles for conductive particles, and can obtain a connection structure excellent in connection reliability. Another object of the present invention is to provide conductive particles, a conductive material, and a connection structure using the resin particles.

Means for Solving the Problems

[0011] The resin particles of the present invention have a 5% weight loss temperature of 350°C or higher, a 10% K value at 25°C of 100 N / mm 2 or higher and 2500 N / mm 2 or lower, and a 30% K value at 25°C of 100 N / mm 2 or higher and 1500 N / mm 2 or lower. The present invention will be described in detail below.

[0012] The inventors of the present invention have found that resin particles with a 5% weight loss temperature of a specific temperature or higher and 10% K value and 30% K value within specific ranges respectively are excellent in heat resistance, and when used as base particles for conductive particles, they can meet the requirements of thermocompression bonding mounting at low pressure and obtain a connection structure with excellent connection reliability, thus completing the present invention.

[0013] The resin particles of the present invention have a lower limit of 5% weight loss temperature of 350 °C. Due to the 5% weight loss temperature being 350 °C or higher, the resin particles of the present invention are excellent in heat resistance and are suitable for applications in high-temperature environments such as in-vehicle use. The preferable lower limit of the 5% weight loss temperature is 360 °C, more preferably 380 °C, and even more preferably 400 °C. Also, there is no particular upper limit for the above 5% weight loss temperature, but the substantial upper limit is 600 °C. The 5% weight loss temperature can be determined as the temperature at which 5% weight loss occurs when thermogravimetric measurement is performed under a nitrogen atmosphere at a heating rate of 5 °C / min from 35 °C to 1000 °C using a differential thermal and thermogravimetric simultaneous measurement device. Examples of the differential thermal and thermogravimetric simultaneous measurement device include TG / DTA6300 (manufactured by Hitachi High-Tech Science Corporation).

[0014] The resin particles of the present invention have a lower limit of 10% K value at 25 °C of 100 N / mm 2 , and an upper limit of 2500 N / mm 2 . When the 10% K value is 100 N / mm 2 or higher, a uniform gap can be maintained when used as the base particles of the conductive particles for the connection structure, and the resulting connection structure will be excellent in reliability. When the 10% K value is 2500 N / mm 2 or lower, it can preferably cope with thermocompression bonding mounting at low pressure when used as the base particles of the conductive particles. The preferable lower limit of the 10% K value is 150 N / mm 2 , more preferably 320 N / mm 2 , and even more preferably 400 N / mm 2 , and the preferable upper limit is 2000 N / mm2 , a more preferable upper limit is 1900 N / mm 2 , a still more preferable upper limit is 1500 N / mm 2 . Note that the above 10% K value and the 30% K value described later can be obtained by measuring the compression displacement (μm) when resin particles are compressed under the conditions of 25°C, a compression speed of 0.3 mN / second, and a maximum test load of 10 mN with a smooth indenter end face of a diamond cylinder with a diameter of 50 μm using a compression testing machine. Examples of the above compression testing machine include Fisherscope H-100 (manufactured by Fisher). K value (N / mm 2 ) = (3 / √2)·F·S -3 / 2 ·R -1 / 2 In the above formula, F is the load value (N) when the particles are compressed by 10% or 30%, S is the compression displacement (mm) when the particles are compressed by 10% or 30%, and R is the radius (mm) of the short side of the particles.

[0015] The resin particles of the present invention have a lower limit of the 30% K value at 25°C of 100 N / mm 2 and an upper limit of 1500 N / mm 2 . When the above 30% K value is 100 N / mm 2 or more, a uniform gap can be maintained when used as the base particles of the conductive particles for the connection structure, and the resulting connection structure has excellent reliability. When the above 30% K value is 1500 N / mm 2 or less, it can preferably cope with thermocompression bonding mounting at a low pressure when used as the base particles of the conductive particles. The preferable lower limit of the above 30% K value is 150 N / mm 2 , a more preferable lower limit is 200 N / mm 2 , a still more preferable lower limit is 240 N / mm 2 , and the preferable upper limit is 900 N / mm 2 , a more preferable upper limit is 720 N / mm 2 , a still more preferable upper limit is 700 N / mm 2 .

[0016] The resin particles of the present invention preferably have an upper limit of the coefficient of variation of the aspect ratio of 10%. When the coefficient of variation of the aspect ratio is 10% or less, a more uniform gap can be maintained when used as the base particles of the conductive particles, and short - circuiting in the lateral direction between the electrodes can be avoided. Therefore, the resulting connection structure is more excellent in reliability. A more preferable upper limit of the coefficient of variation of the aspect ratio is 3%, a still more preferable upper limit is 2%, and a particularly preferable upper limit is 1%. Although there is no particular lower limit for the coefficient of variation of the aspect ratio, the practical lower limit is 0.1%. The coefficient of variation of the aspect ratio can be obtained by the following formula from the standard deviation and the average value after taking a particle image with a scanning electron microscope and measuring the long side and the short side of 50 particles in the obtained image with calipers to obtain the aspect ratio. Examples of the scanning electron microscope include Regulus - 8220 (manufactured by Hitachi High - Technologies Corporation). Coefficient of variation of aspect ratio (%)=(σa÷Σa)×100 In the above formula, σa is the standard deviation of the aspect ratio, and Σa is the average value of the aspect ratio.

[0017] The resin particles of the present invention preferably have a lower limit of the average particle diameter of 0.1 μm and an upper limit of 1000 μm. When the average particle diameter is 0.1 μm or more, it becomes difficult to form aggregated conductive particles when forming the conductive layer. When the average particle diameter is 1000 μm or less, when connecting between electrodes using the conductive particles, the contact area between the conductive particles and the electrodes becomes sufficiently large. If the average particle diameter is too large, it becomes difficult to sufficiently compress the conductive particles, and thus the connection resistance value between the electrodes may increase. A more preferable lower limit of the average particle diameter is 1.0 μm, and a more preferable upper limit is 500 μm. The average particle diameter is the number - average particle diameter, which can be obtained by taking a particle image with a scanning electron microscope and measuring the short sides of 50 particles in the obtained image with calipers and taking the average value.

[0018] The resin particles of the present invention preferably have an upper limit of 20% for the coefficient of variation of the particle diameter measured by particle size distribution measurement. When the coefficient of variation of the particle diameter is 20% or less, a more uniform gap can be maintained when used as the base particles of the conductive particles used in the connection structure, and the resulting connection structure will be more excellent in reliability. A more preferable upper limit of the coefficient of variation of the particle diameter is 11%, and an even more preferable upper limit is 10%. There is no particular lower limit for the coefficient of variation of the particle diameter, but the substantial lower limit is 0.1%. The coefficient of variation of the particle diameter can be obtained by the following formula by deriving the standard deviation and the average value of the particle diameter using a particle size distribution measuring device of the laser diffraction scattering method. Examples of the particle size distribution measuring device include LS 13 320 (wet system) (manufactured by Beckman Coulter). Coefficient of variation of particle diameter (%) = (σs ÷ Σs) × 100 In the above formula, σs is the standard deviation of the particle diameter, and Σs is the average value of the particle diameter.

[0019] The resin particles of the present invention preferably have an upper limit of 200% for the change amount of the 30% K value before and after heating when heated at 200 ° C for 24 hours. When the change amount of the 30% K value before and after heating is 200% or less, when used as the base particles of the conductive particles, damage to the conductive layer and the substrate surface due to hardening of the particles can be suppressed during use at high temperatures. A more preferable upper limit of the change amount of the 30% K value before and after heating is 140%, an even more preferable upper limit is 120%, and a particularly preferable upper limit is 90%. Also, there is no particular lower limit for the change amount of the 30% K value before and after heating, but the substantial lower limit is 0%. When the change amount of the 30% K value before and after heating is below the lower limit, deterioration of the particles is expected, so there is concern about weakening of the electrode portion and the electrical connection reliability of the connection structure decreases. The change amount of the 30% K value before and after heating can be obtained by the following formula. Change amount of 30% K value before and after heating (%) = (B - A) ÷ A × 100 In the above formula, A is the 30% K value at 25°C before heating, and B is the 30% K value at 25°C after heating at 200°C for 24 hours.

[0020] When the resin particles of the present invention are used for the base particle application of conductive particles, the recovery rate is preferably 2.5% or more and 25% or less. When the above recovery rate is 2.5% or more, the conduction reliability between electrodes can be effectively enhanced. When the above recovery rate is 25% or less, when mounted at a low pressure, the occurrence of springback can be effectively suppressed, and the reduction in the conduction reliability of the connection structure can be suppressed. The more preferable lower limit of the above recovery rate is 3.5%, and the more preferable upper limit is 21%. Note that the above recovery rate means a value expressed as a percentage of L2 / L1, where L1 is the compression displacement from the origin load value when applying a load to a predetermined reverse load value, and L2 is the unloading displacement from the reverse load value when releasing the load to the origin load value. Specifically, it can be derived by using a compression tester, applying a load to the resin particles with the smooth end face of a diamond column having a diameter of 50 μm at 25°C, a compression speed of 0.3 mN / second, an origin load value of 1.0 mN, and a reverse load value of 10 mN, and analyzing the recovery behavior after removing the load. Recovery rate (%) = [L2 / L1] × 100

[0021] The 5% weight loss temperature, 10% K value at 25°C, and 30% K value at 25°C of the resin particles of the present invention can be easily adjusted to the above-mentioned ranges by selecting the material constituting the resin particles.

[0022] The resin particles of the present invention preferably have a main chain skeleton containing an imide group. Specifically, for example, resin particles composed of polybismaleimide, a copolymer of bismaleimide and a compound having an unsaturated double bond, polyimide, etc. can be mentioned. Among these, the resin particles of the present invention preferably have segments derived from bismaleimide. By having segments derived from the above bismaleimide, that is, by using a polymer obtained by using bismaleimide as a polymerizable monomer, it becomes easier to make the 5% weight loss temperature, the 10% K value at 25°C, and the 30% K value at 25°C fall within the above-described ranges.

[0023] Specific examples of the bismaleimide include, for example, compounds represented by the following formula (1), compounds represented by the following formula (2), compounds represented by the following formula (3), BMI-1700 (manufactured by DESIGNER MOLECULES), BMI-2500 (manufactured by DESIGNER MOLECULES), BMI-3000 (manufactured by DESIGNER MOLECULES), BMI-5000 (manufactured by DESIGNER MOLECULES), BMI-6000 (manufactured by DESIGNER MOLECULES), 1,2-bis(maleimide)ethane, 1,4-bis(maleimide)butane, 4,4'-bismaleimidodiphenylmethane, 4,4'-diphenylmethanebismaleimide, bis-(3-ethyl-4-maleimidophenyl)methane, 2,2'-bis-[4-(4-maleimidophenoxy)phenyl]propane, 4,4'-diphenylmethanebismaleimide, 1,4-phenylenebismaleimide, 1,3-phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl sulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, 1-maleimide-3-maleimidomethyl-3,5,5-trimethylcyclohexane, 1,1'-(cyclohexane-1,3-diylbis(methylene))bis(1H-pyrrole-2,5-dione), 1,1'-(4,4'-methylenebis(cyclohexane-4,1-diyl))bis(1H-pyrrole-2,5-dione), 1,1'-(3,3'-(piperazine-1,4-diyl)bis(propane-3,1-diyl))bis(1H-pyrrole-2,5-dione), 2,2'-(ethylenedioxy)bis(ethylmaleimide), etc. Among these, compounds represented by the following formula (1), compounds represented by the following formula (2), and compounds represented by the following formula (3) are preferred. Examples of commercially available compounds represented by the following formula (1) include, for example, BMI-689 (manufactured by DESIGNER MOLECULES). Examples of commercially available compounds represented by the following formula (2) include, for example, BMI-1400 (manufactured by DESIGNER MOLECULES). Examples of commercially available compounds represented by the following formula (3) include, for example, BMI-1500 (manufactured by DESIGNER MOLECULES).

[0024]

Chemical formula

[0025]

Chemical formula

[0026] In formula (2), n is an integer of 1 or more and 10 or less.

[0027]

Chemical formula

[0028] In formula (3), m is an integer of 1 or more and 2 or less.

[0029] The compound having the above unsaturated double bond may be a non-crosslinkable monomer or a crosslinkable monomer.

[0030] Examples of the non-crosslinkable monomer include, for example, styrene monomers, N-alkyl group-substituted maleimide monomers, N-aryl group-substituted maleimide monomers, N-acyl group-substituted maleimide monomers, other non-crosslinkable maleimide monomers, carboxyl group-containing monomers, alkyl (meth) acrylates, oxygen atom-containing (meth) acrylates, nitrile-containing monomers, vinyl ester compounds, unsaturated hydrocarbons, halogen-containing monomers, and the like.

[0031] Examples of the styrene monomer include styrene, α-methylstyrene, and the like. Examples of the N-alkyl group-substituted maleimide monomer include N-methylmaleimide, N-ethylmaleimide, N-benzylmaleimide, and the like. Examples of the N-aryl group-substituted maleimide monomer include N-ethylmaleimide, N-(4-aminophenyl)maleimide, N-(9-acridinyl)maleimide, and the like. Examples of the N-acyl group-substituted maleimide monomer include N-methoxycarbonylmaleimide and the like. Examples of the other non-crosslinkable maleimide monomer include succinimidyl-4-(N-maleimidomethyl)cyclo-hexane-1-carboxylate, N-succinimidyl-3-maleimidopropionate, and the like. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, maleic acid, maleic anhydride, and the like. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like. Examples of the oxygen atom-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, glycidyl (meth)acrylate, and the like. Examples of the nitrile-containing monomer include (meth)acrylonitrile and the like. Examples of the vinyl ester compound of an acid include vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, and the like. Examples of the unsaturated hydrocarbon include ethylene, propylene, isoprene, butadiene, and the like. Examples of the halogen-containing monomer include trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, chlorostyrene, and the like.

[0032] Examples of the crosslinkable monomer include polyfunctional (meth)acrylate, silane-containing monomer, and the like.

[0033] Examples of the polyfunctional (meth)acrylate include tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and the like. Examples of the silane-containing monomer include triallyl (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane, and the like.

[0034] When the resin particles of the present invention have a segment derived from the above bismaleimide, the preferable lower limit of the content ratio of the segment derived from the above bismaleimide is 0.1 mol%. When the content ratio of the segment derived from the above bismaleimide is 0.1 mol% or more, it becomes easier to make the 5% weight loss temperature, the 10% K value at 25°C, and the 30% K value at 25°C fall within the above-mentioned ranges. The more preferable lower limit of the content ratio of the segment derived from the above bismaleimide is 3.0 mol%, the still more preferable lower limit is 9.0 mol%, and the particularly preferable lower limit is 20 mol%. In particular, the 5% weight loss temperature can be easily adjusted according to the content ratio of the segment derived from the above bismaleimide contained in the resin particles, and can be increased by increasing the content ratio of the segment derived from the above bismaleimide, and can be decreased by reducing the content ratio of the segment derived from the above bismaleimide. Also, regarding the 10% K value at 25°C and the 30% K value at 25°C, they can be decreased by increasing the content ratio of the segment derived from the above bismaleimide, and can be increased by reducing the content ratio of the segment derived from the above bismaleimide.

[0035] When the resin particles of the present invention have imide groups, the preferable lower limit of the imide group content is 0.01%, and the preferable upper limit is 80%. When the content of the above imide groups is 0.01% or more, polymer particles having a main chain skeleton with more excellent heat resistance are obtained. When the content of the above imide groups is 80% or less, it becomes easier to make the 10% K value at 25°C and the 30% K value at 25°C within the above-mentioned ranges. The more preferable lower limit of the content of the above imide groups is 5%, the further preferable lower limit is 7.5%, and the more preferable upper limit is 50%. In particular, the 5% weight loss temperature can also be easily adjusted according to the content ratio of the above imide groups contained in the resin particles, and can be increased by increasing the content ratio of the imide groups, and can be decreased by reducing the content ratio of the imide groups. The content ratio of the above imide groups can be determined by the following formula. Content ratio of imide groups (%) = C ÷ D × 100 In the above formula, C is the total molecular weight of the imide group portions contained in the repeating unit, and D is the total molecular weight of the repeating structural units of the resin constituting the resin particles. When the resin particles of the present invention are copolymer particles, the molar fraction of each repeating structural unit is calculated, and the calculated total molecular weight is taken as D. For example, in the case of Example 2 described later, since the molar fraction of the structural unit of the compound represented by formula (1) is 0.5 and the molar fraction of the structural unit of styrene is 0.5, D = Molecular weight of the compound represented by formula (1) × mole fraction + Molecular weight of styrene × mole fraction = 689 × 0.5 + 104.15 × 0.5 = 396.575 It is calculated as follows.

[0036] As the polymerization method for producing the resin particles of the present invention, specifically, for example, conventionally known polymerization methods such as suspension polymerization method, emulsion polymerization method, seed polymerization method, dispersion polymerization method, etc. can be mentioned. Among them, since the particle size distribution is relatively wide and polymer particles with polydispersity can be obtained, the above suspension polymerization method and the above emulsion polymerization method are suitable for the purpose of producing fine particles with various particle diameters. When using the above suspension polymerization method and the above emulsion polymerization method, it is preferable to classify the polymer particles obtained by polymerization and select the polymer particles having a desired particle diameter or particle size distribution.

[0037] The conductive particles having the resin particles of the present invention and the conductive layer formed on the surface of the resin particles are also one of the present inventions.

[0038] Examples of the material constituting the conductive layer 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, tin-doped indium oxide (ITO), etc. Among them, since the connection resistance between electrodes can be further reduced, alloys containing tin, nickel, palladium, gold, copper, or silver are preferable, alloys containing tin, nickel, palladium, gold, or copper are more preferable, and nickel or palladium is even more preferable.

[0039] As a method for forming the conductive layer on the surface of the resin particles, for example, a method by electroless plating, a method by electroplating, a method by physical vapor deposition, a method of coating the surface of the resin particles with a paste containing metal powder or a metal powder and a binder, etc. can be mentioned. Since the formation of the conductive layer is simple, the method for forming the conductive layer is preferably a method by electroless plating. Examples of the method by physical vapor deposition include methods such as vacuum evaporation, ion plating, and ion sputtering.

[0040] The conductive particles of the present invention preferably have an insulating material on the outer surface of the conductive layer. By having an insulating material on the outer surface of the conductive layer, when the obtained conductive particles are used for connection between electrodes, short-circuiting between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles come into contact, since an insulating material exists between the plurality of electrodes, short-circuiting between electrodes adjacent in the lateral direction rather than between the upper and lower electrodes can be prevented. When connecting the electrodes, by pressing the conductive particles with two electrodes, the insulating substance between the conductive layer of the conductive particles and the electrodes can be easily removed. Further, when the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating substance between the conductive layer of the conductive particles and the electrodes can be more easily removed.

[0041] Since the insulating material can be more easily removed during crimping between electrodes, the insulating material is preferably insulating particles.

[0042] Examples of the insulating material include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, cross-linked products of thermoplastic resins, thermosetting resins, water-soluble resins, etc. The insulating material may be used alone or in combination of two or more.

[0043] Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, etc. Examples of the above (meth)acrylate polymer include polymethyl (meth)acrylate, polydodecyl (meth)acrylate, and polystyryl (meth)acrylate. Examples of the above block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the above thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the above thermosetting resin include epoxy resin, phenol resin, and melamine resin. Examples of the crosslinked product of the above thermoplastic resin include the introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate, etc. Examples of the above water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose.

[0044] When manufacturing the above insulating material, a chain transfer agent may be used to adjust the degree of polymerization. Examples of the above chain transfer agent include thiol and carbon tetrachloride.

[0045] Examples of the method for disposing the above insulating material on the outer surface of the above conductive layer include chemical methods, physical or mechanical methods, etc. Examples of the above chemical method include interfacial polymerization method, suspension polymerization method in the presence of particles, emulsion polymerization method, etc. Examples of the above physical or mechanical method include spray drying, hybridization, electrostatic deposition method, spraying method, dipping, method by vacuum evaporation, etc. Among them, since the above insulating material is difficult to desorb, a method of disposing the above insulating material on the outer surface of the above conductive layer via a chemical bond is preferable.

[0046] The outer surface of the conductive layer and the surface of the insulating material may each be coated with a compound having a reactive functional group. The outer surface of the conductive layer and the surface of the insulating material may not be directly chemically bonded, and may be indirectly chemically bonded by a compound having a reactive functional group. For example, after introducing a carboxyl group onto the outer surface of the conductive layer, the carboxyl group may be chemically bonded to the functional group on the surface of the insulating material via a polyelectrolyte such as polyethyleneimine.

[0047] The conductive particles of the present invention preferably have protrusions on the outer surface of the conductive layer. By having protrusions on the outer surface of the conductive layer, the obtained conductive particles can further enhance the conduction reliability between electrodes. An oxide film is often formed on the surface of the electrode connected by the conductive particles. In addition, an oxide film is often formed on the surface of the conductive layer of the conductive particles. By using the conductive particles having the protrusions, after arranging the conductive particles between the electrodes and then crimping them, the oxide film is effectively removed by the protrusions. Therefore, the electrode and the conductive particles can be made to contact more surely, and the connection resistance between the electrodes can be made lower more effectively. Further, when the conductive particles have the insulating material on the surface, or when 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 is effectively removed by the protrusions of the conductive particles. Therefore, the conduction reliability between the electrodes can be enhanced more effectively.

[0048] Examples of the method for forming protrusions on the outer surface of the conductive layer include a method of embedding a core material in the conductive layer. By embedding the core material in the conductive layer, a plurality of protrusions can be easily formed on the outer surface of the conductive layer. However, in order to form protrusions on the outer surface of the conductive layer of the conductive particles, it is not necessarily required to use a core material.

[0049] As a method for forming the above-mentioned protrusions, specifically, for example, after adhering a core material to the surface of resin particles, a method of forming a conductive layer by electroless plating, or after forming a conductive layer on the surface of resin particles by electroless plating, adhering a core material and then forming a conductive layer by electroless plating, etc. can be mentioned. As another method for forming the above-mentioned protrusions, for example, after forming a first conductive layer on the surface of resin particles, disposing a core material on the first conductive layer, and then forming a second conductive layer, or a method of adding a core material during the process of forming a conductive layer (such as the first conductive layer or the second conductive layer, etc.) on the surface of resin particles can be mentioned. Further, in order to form the above-mentioned protrusions, after forming a conductive layer on resin particles by electroless plating without using the above-mentioned core material, plating is deposited in a protrusion shape on the surface of the conductive layer, and then a method of forming a conductive layer by electroless plating, etc. may be used.

[0050] As a method for adhering a core material to the surface of the above-mentioned resin particles, for example, in a dispersion liquid of resin particles, adding a core material and adhering the core material to the surface of the resin particles by accumulating it by van der Waals force, or adding a core material to a container containing resin particles and adhering the core material to the surface of the resin particles by a mechanical action such as rotation of the container, etc. can be mentioned. Among them, since it is easy to control the amount of the core material to be adhered, a method of accumulating and adhering the core material to the surface of the resin particles in the dispersion liquid is preferable.

[0051] The material of the above-mentioned core material may be a conductive substance or a non-conductive substance. Examples of the above-mentioned conductive substances include metals, metal oxides, conductive non-metals such as graphite, conductive polymers, etc. Examples of the above-mentioned conductive polymers include polyacetylene, etc. Examples of the above-mentioned non-conductive substances include silica, alumina, titanium oxide, barium titanate, zirconia, etc. Among them, as the material of the core substance, a metal is preferable because it can enhance conductivity and further effectively reduce the contact resistance, and the core substance is preferably metal particles. As the metal that is the material of the core substance, the metals listed as the materials constituting the conductive layer can be appropriately used.

[0052] The conductive material containing the conductive particles and the binder resin of the present invention is also one of the present inventions.

[0053] As the binder resin, an insulating resin is used. For example, vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, elastomers, etc. are mentioned. The binder resin may be used alone or in combination of two or more.

[0054] Examples of the vinyl resin include vinyl acetate resin, acrylic resin, styrene resin, etc. Examples of the thermoplastic resin include polyolefin resin, ethylene-vinyl acetate copolymer, polyamide resin, etc. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, unsaturated polyester resin, etc. The curable resin may be any of room temperature curable resin, heat curable resin, photo curable resin, moisture curable resin. Further, the curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated product of styrene-butadiene-styrene block copolymer, hydrogenated product of styrene-isoprene-styrene block copolymer, etc. Examples of the elastomer include styrene-butadiene copolymer rubber, acrylonitrile-styrene block copolymer rubber, etc.

[0055] In addition to the above conductive particles and the above binder resin, the conductive material of the present invention may contain various additives such as, for example, fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, flame retardants, and the like.

[0056] In the conductive material of the present invention, the conductive particles of the present invention are preferably dispersed in the binder resin. As a method for dispersing the conductive particles in the binder resin, a conventionally known dispersion method can be used. Specifically, for example, after adding the conductive particles to the binder resin, a method of kneading and dispersing with a planetary mixer or the like, or a method of uniformly dispersing the conductive particles in water or an organic solvent using a homogenizer or the like and then adding them to the binder resin and kneading and dispersing with a planetary mixer or the like, or a method of diluting the binder resin with water or an organic solvent or the like, adding the conductive particles, and kneading and dispersing with a planetary mixer or the like can be mentioned.

[0057] The conductive material of the present invention can be used, for example, as an anisotropic conductive paste, anisotropic conductive ink, anisotropic conductive adhesive, anisotropic conductive film, anisotropic conductive sheet, or the like. When the conductive material of the present invention is used as a film-like adhesive such as an anisotropic conductive film or anisotropic conductive sheet, a film-like adhesive containing no conductive particles may be laminated on the film-like adhesive containing the conductive particles.

[0058] The preferable lower limit of the content of the binder resin in 100 parts by weight of the conductive material of the present invention is 10 parts by weight, and the preferable upper limit is 99.99 parts by weight. When the content of the binder resin is within this range, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material of the present invention is further improved. The more preferable lower limit of the content of the binder resin is 30 parts by weight, the further preferable lower limit is 50 parts by weight, the particularly preferable lower limit is 70 parts by weight, and the more preferable upper limit is 99.9 parts by weight.

[0059] In 100 parts by weight of the conductive material of the present invention, the preferable lower limit of the content of the conductive particles is 0.01 part by weight, and the preferable upper limit is 80 parts by weight. When the content of the conductive particles is within this range, it is possible to suppress deterioration such as coatability and to more effectively exhibit effects such as improvement in conductivity. The more preferable lower limit of the content of the conductive particles is 0.1 part by weight, and the more preferable upper limit is 10 parts by weight.

[0060] The conductive material of the present invention may contain various additives such as a filler, a bulking agent, a softening agent, a plasticizer, a polymerization catalyst, a curing catalyst, a coloring agent, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, and a flame retardant, as long as the object of the present invention is not inhibited.

[0061] By using the conductive particles of the present invention, a connection structure excellent in connection reliability can be obtained. A connection structure including a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and a connection portion connecting the first connection target member and the second connection target member, wherein the constituent material of the connection portion is the conductive particles of the present invention or the conductive material of the present invention is also one of the present inventions.

[0062] The resin particles of the present invention have high compression deformation during initial compression, can maintain a constant gap, and can suppress damage to the substrate, and thus are also preferably used as spacers for liquid crystal display elements and the like.

Effects of the Invention

[0063] According to the present invention, it is possible to provide resin particles that are excellent in heat resistance, can cope with thermocompression bonding mounting at a low pressure when used for base particles of conductive particles, and can obtain a connection structure excellent in connection reliability. Further, according to the present invention, it is possible to provide conductive particles, a conductive material, and a connection structure using the resin particles.

Modes for Carrying Out the Invention

[0064] Examples are given below to explain the present invention in more detail, but the present invention is not limited to these examples only.

[0065] (Example 1) In a reaction vessel equipped with a thermometer and a cooling tube, 4.6 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689") and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") as a dispersion stabilizer, 0.4 parts by weight of sodium dodecylbenzenesulfate, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and stirred with heating for 24 hours to obtain resin particles 1.

[0066] (Example 2) In a reaction vessel equipped with a thermometer and a cooling tube, 4.0 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 0.6 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") as a dispersion stabilizer, 0.4 parts by weight of sodium dodecylbenzenesulfate, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and stirred with heating for 24 hours to obtain resin particles 2.

[0067] (Example 3) In a reaction vessel equipped with a thermometer and a cooling pipe, 3.5 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 1.1 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Gosei Chemical Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and heated and stirred for 24 hours to obtain resin particles 3.

[0068] (Example 4) In a reaction vessel equipped with a thermometer and a cooling pipe, 2.8 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 0.5 parts by weight of ethylmaleimide, 1.3 parts by weight of styrene, and 0.2 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Gosei Chemical Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and heated and stirred for 24 hours to obtain resin particles 4.

[0069] (Example 5) In a reaction vessel equipped with a thermometer and a cooling tube, 1.8 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 1.3 parts by weight of ethyl maleimide, 1.6 parts by weight of styrene, and 0.2 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and stirred with heating for 24 hours to obtain resin particles 5.

[0070] (Example 6) In a reaction vessel equipped with a thermometer and a cooling tube, 0.7 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 2.0 parts by weight of ethyl maleimide, 1.9 parts by weight of styrene, and 0.2 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and stirred with heating for 24 hours to obtain resin particles 6.

[0071] (Example 7) In a reaction vessel equipped with a thermometer and a cooling tube, 0.3 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 2.4 parts by weight of ethyl maleimide, 2.0 parts by weight of styrene, and 0.2 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and heated with stirring for 24 hours to obtain resin particles 7.

[0072] (Example 8) In a reaction vessel equipped with a thermometer and a cooling tube, 4.6 parts by weight of the compound represented by the above formula (2) (manufactured by DESIGNER MOLECULES, "BMI-1400") and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and heated with stirring for 24 hours to obtain resin particles 8.

[0073] (Example 9) In a reaction vessel equipped with a thermometer and a cooling tube, 4.1 parts by weight of the compound represented by the above formula (2) (manufactured by DESIGNER MOLECULES, "BMI-1400"), 0.5 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and heated and stirred for 24 hours to obtain resin particles 9.

[0074] (Example 10) In a reaction vessel equipped with a thermometer and a cooling tube, 4.6 parts by weight of the compound represented by the above formula (3) (manufactured by DESIGNER MOLECULES, "BMI-1500") and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65 °C and heated and stirred for 24 hours to obtain resin particles 10.

[0075] (Example 11) In a reaction vessel equipped with a thermometer and a cooling tube, 4.0 parts by weight of the compound represented by the above formula (3) (manufactured by DESIGNER MOLECULES, "BMI-1500"), 0.6 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the obtained solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and heated with stirring for 24 hours to obtain resin particles 11.

[0076] (Example 12) In a reaction vessel equipped with a thermometer and a cooling tube, 3.9 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 0.5 parts by weight of divinylbenzene, 0.2 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the obtained solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65°C and heated with stirring for 24 hours to obtain resin particles 12.

[0077] (Example 13) In a reaction vessel equipped with a thermometer and a cooling pipe, 3.9 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 0.7 parts by weight of divinylbenzene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 4.6 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65°C and heated with stirring for 24 hours to obtain resin particles 13.

[0078] (Example 14) In a reaction vessel equipped with a thermometer and a cooling pipe, 2.4 parts by weight of ethylmaleimide, 2.0 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were mixed with 4.4 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as dispersion stabilizers, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The resulting suspension was heated to 65°C and heated with stirring for 24 hours to obtain resin particles 14.

[0079] (Example 15) In a reaction vessel equipped with a thermometer and a cooling pipe, 4.6 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689") and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were mixed with 3.0 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65 °C and heated with stirring for 24 hours to obtain resin particles 15.

[0080] (Example 16) In a reaction vessel equipped with a thermometer and a cooling pipe, 4.0 parts by weight of the compound represented by the above formula (1) (manufactured by DESIGNER MOLECULES, "BMI-689"), 0.6 parts by weight of styrene, and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 2.0 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and the mixture was stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65 °C and heated with stirring for 24 hours to obtain resin particles 16.

[0081] (Comparative Example 1) Polyimide P84 NT (manufactured by Daicel Evonik Co., Ltd.) was used as resin particles 17.

[0082] (Comparative Example 2) Divinylbenzene copolymer resin particles (manufactured by Sekisui Chemical Co., Ltd., "Micropearl") were used as resin particles 18.

[0083] (Comparative Example 3) In a reaction vessel equipped with a thermometer and a cooling pipe, 4.4 parts by weight of light acrylate MPD-A (manufactured by Kyoeisha Chemical Co., Ltd.), 0.2 parts by weight of A-TMMT (manufactured by Shin-Nakamura Chemical Co., Ltd.), and 0.3 parts by weight of 2,2'-azobis(isobutyronitrile) as a polymerization initiator were dissolved in 2.0 parts by weight of toluene. To the resulting solution, 13.1 parts by weight of a 5.5 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Gosenol GH-20") and 0.4 parts by weight of sodium dodecylbenzenesulfate as a dispersion stabilizer, and 180 parts by weight of ultrapure water were added, and stirred using a high-speed homogenizer (manufactured by Central Scientific Trading Co., Ltd., "Polytron PT-3100") to obtain a suspension. The obtained suspension was heated to 65 °C and heated and stirred for 24 hours to obtain resin particles 19.

[0084] (Comparative Example 4) According to Non-Patent Document 1, resin particles were prepared as follows. In a reaction vessel equipped with a thermometer, a stirrer, and a cooling pipe, 0.1 mol of 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 0.05 mol of 1,4-bis(4-aminophenoxy)benzene, and 0.05 mol of bis[4-(3-aminophenoxy)phenyl]sulfone were dissolved in 500 mL of N,N-dimethylformamide. The resulting solution was stirred at 25 °C for 24 hours to obtain a solution of polyamic acid, which is a prepolymer of polyimide. 100 mL of toluene was added to the obtained solution, and heated under reflux for 4 hours under a nitrogen atmosphere to obtain resin particles 20.

[0085] (5% Thermogravimetric Decrease Temperature) 10 mg of each of the resin particles obtained in the examples and comparative examples was weighed into an aluminum pan, and thermogravimetric measurement was performed under a nitrogen atmosphere at a heating rate of 5 °C / min from 35 °C to 1000 °C using a differential thermal thermogravimetric simultaneous measurement device, and the temperature at which a 5% weight decrease occurred was determined. The results are shown in Tables 1 and 2. As the differential thermal thermogravimetric simultaneous measurement device, TG / DTA6300 (manufactured by Hitachi High-Technologies Corporation) was used.

[0086] (10% K Value and 30% K Value) For each of the resin particles obtained in Examples 1 to 16 and Comparative Examples 2 and 3, using a compression tester, the compression displacement (μm) when compressed at 25°C, a compression speed of 0.3 mN / second, and a maximum test load of 10 mN with the smooth pressing surface of a diamond cylinder with a diameter of 50 μm was measured, and the 10% K value and 30% K value were determined by the above-described formula. The results are shown in Tables 1 and 2. As the compression tester, Fisherscope H-100 (manufactured by Fisher) was used.

[0087] (Coefficient of variation of aspect ratio and average particle diameter) For each of the resin particles obtained in the Examples and Comparative Examples, particle images were taken with a scanning electron microscope, and the aspect ratio was determined by measuring the long side and short side of 50 particles in the obtained images with calipers. Then, the coefficient of variation of the aspect ratio was determined by the above-described formula from their standard deviation and average value. Also, the average value of the short sides of 50 particles in the obtained images was determined as the average particle diameter. The results are shown in Tables 1 and 2. As the scanning electron microscope, Regulus-8220 (manufactured by Hitachi High-Technologies Corporation) was used.

[0088] (Coefficient of variation of particle diameter) For each of the resin particles obtained in the Examples and Comparative Examples, using a particle size distribution measuring device based on the laser diffraction scattering method, the standard deviation and average value of the particle diameter were derived, and the coefficient of variation of the particle diameter was determined by the above-described formula. The results are shown in Tables 1 and 2. As the particle size distribution measuring device, LS 13 320 (wet system) (manufactured by Beckman Coulter) was used.

[0089] (Change amount of 30% K value before and after heating) For each of the resin particles obtained in Examples 1 to 16 and Comparative Examples 2 to 4, they were heated at 200°C for 24 hours. From the measurement results of the 30% K value at 25°C before and after heating, the change amount of the 30% K value before and after heating was determined by the above-described formula. The results are shown in Tables 1 and 2.

[0090] (Recovery rate) For each of the resin particles obtained in Examples 1 to 16 and Comparative Examples 2 to 4, using a compression tester, the resin particles were loaded with a smooth end face of a diamond cylinder with a diameter of 50 μm under the conditions of 25°C, a compression rate of 0.3 mN / second, an initial load value of 1.0 mN, and a reverse load value of 10 mN. After removing the load, the recovery behavior was analyzed, and the recovery rate was derived by the method described above. The results are shown in Tables 1 and 2. As the compression tester, Fisherscope H-100 (manufactured by Fisher) was used.

[0091] (Content ratio of imide group) For each of the resin particles obtained in Examples 1 to 16 and Comparative Examples 2 to 4, the content ratio of the imide group was determined by the above-described formula. The results are shown in Tables 1 and 2.

[0092] <Evaluation> The following evaluations were performed on each of the resin particles obtained in the Examples and Comparative Examples. The results are shown in Tables 1 and 2.

[0093] (1) Long-term connection reliability under high-temperature conditions (1-1) Preparation of conductive particles 10 parts by weight of each of the resin particles obtained in the examples and comparative examples were dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and then the solution was filtered to take out the resin particles. 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 resin particles with activated surfaces 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 diameter 100 nm) was added to the dispersion over 3 minutes to obtain a suspension containing resin particles with core substances attached. Also, a nickel plating solution (pH 8.5) containing 0.35 mol / L of nickel sulfate, 1.38 mol / L of dimethylamine borane, and 0.5 mol / L of sodium citrate was prepared. While stirring the obtained suspension at 60 °C, the nickel plating solution was gradually dropped into the suspension to perform electroless nickel plating. Thereafter, the suspension was filtered to take out the particles, washed with water, and dried to obtain conductive particles having a nickel-boron conductive layer (thickness 0.15 μm) on the surface of the resin particles.

[0094] (1-2) Preparation of Insulating Particles A monomer composition containing 100 mmol of methyl methacrylate, 1 mmol of N,N,N-trimethyl-N-2-methacryloyloxyethylammonium chloride, and 1 mmol of 2,2'-azobis(2-amidinopropane) dihydrochloride was weighed into ion-exchanged water so that the solid content fraction was 5% by weight in a separable flask. As the separable flask, a 1000 mL one equipped with a four-neck separable cover, a stirring blade, a three-way cock, a condenser, and a temperature probe was used. Thereafter, it was stirred at 200 rpm and polymerized at 70 °C for 24 hours under a nitrogen atmosphere. After completion of the reaction, it was freeze-dried to obtain insulating particles having an ammonium group on the surface, an average particle diameter of 220 nm, and a CV value of the particle diameter of 10%.

[0095] (1-3) Preparation of Conductive Particles with Insulating Particles The insulating particles obtained in the above “(1-2) Preparation of Insulating Particles” were dispersed in distilled water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles. Next, 10 g of the conductive particles obtained in the above “(1-1) Preparation of Conductive Particles” were dispersed in 500 mL of distilled water, 1 g of a 10 wt% aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 8 hours. After filtering through a 3-μm mesh filter, it was further washed with methanol and dried to obtain conductive particles with insulating particles.

[0096] (1-4) Preparation of Conductive Material (Anisotropic Conductive Paste) 7 parts by weight of the obtained conductive particles with insulating particles, 25 parts by weight of bisphenol A type phenoxy resin, 4 parts by weight of fluorene type epoxy resin, 30 parts by weight of phenol novolak type epoxy resin, and SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd.) were blended and defoamed and stirred for 3 minutes to obtain a conductive material (anisotropic conductive paste).

[0097] (1-5) Preparation of Connection Structure A transparent glass substrate (first connection target member) having an aluminum electrode pattern (first electrode) with a height of 0.2 μm and an L / S of 10 μm / 10 μm formed on the upper surface was prepared. Also, a two-layer flexible substrate (second connection target member) having an aluminum electrode pattern (second electrode) with an L / S of 10 μm / 10 μm formed on the lower surface was prepared. The obtained anisotropic conductive paste was applied onto the transparent glass substrate to a thickness of 15 μm to form an anisotropic conductive paste layer. Next, the two-layer flexible substrate was laminated on the anisotropic conductive paste layer so that the electrodes faced each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer became 180°C, a pressure heating head was placed on the upper surface of the semiconductor chip, and a pressure of 1 MPa was applied to cure the anisotropic conductive paste layer at 180°C to obtain a connection structure.

[0098] (1-6) Evaluation of Long-Term Connection Reliability under High Temperature Conditions 100 of the obtained connection structures were left at 200°C for 24 hours. For the 100 connection structures after leaving, it was confirmed whether or not there was a conduction failure between the upper and lower electrodes. When the number of connection structures with poor conductivity is 1 or less, it is designated as "○○○"; when the number of connection structures with poor conductivity is 2 or more and 5 or less, it is designated as "○○"; when the number of connection structures with poor conductivity is 6 or more and 10 or less, it is designated as "○"; when the number of connection structures with poor conductivity is 11 or more, it is designated as "×". The long-term connection reliability under high-temperature conditions was evaluated accordingly.

[0099] (2) Adhesion between resin particles and conductive parts For the connection structure obtained in the same manner as the above "(1) Long-term connection reliability under high-temperature conditions", the conductive particles in the connection part were observed using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, "Regulus8220"). For 100 observed conductive particles, it was confirmed whether the conductive part (conductive layer) arranged on the surface of the resin particles was peeled off or not. When the number of conductive particles with the conductive part peeled off was 0, it was designated as "○○○"; when it exceeded 0 and was 15 or less, it was designated as "○○"; when it exceeded 15 and was 30 or less, it was designated as "○"; when it exceeded 30 and was 50 or less, it was designated as "×"; when it exceeded 50, it was designated as "××". The adhesion between resin particles and conductive parts was evaluated accordingly.

[0100] (3) Insulation reliability (lateral direction) 100 connection structures obtained in the same manner as the above "(1) Long-term connection reliability under high-temperature conditions" were left at 200 °C for 24 hours. For the 100 connection structures after leaving, in order to confirm the presence or absence of leakage between adjacent electrodes, the resistance value was measured using a tester. Resistance value is 10 8 When the number of connection structures with a resistance value of 10

[0101]

Table 1

[0102]

Table 2

Industrial Applicability

[0103] According to the present invention, it is possible to provide resin particles that are excellent in heat resistance, can cope with thermocompression bonding mounting at a low pressure when used for base particles of conductive particles, and can obtain a connection structure excellent in connection reliability. Further, according to the present invention, it is possible to provide conductive particles, a conductive material, and a connection structure using the resin particles.

Claims

1. Resin particles having a main chain skeleton containing an imide group, The 5% weight loss temperature is 350 °C or higher, and the 10% K value at 25 °C is 100 N / mm ２ or more and 2500 N / mm ２ or less, and the 30% K value at 25 °C is 100 N / mm ２ or more and 1500 N / mm ２ or less, characterized by resin particles.

2. The resin particles according to Claim 1, wherein the coefficient of variation of the aspect ratio is 10% or less.

3. The resin particles according to Claim 1 or 2, wherein the average particle diameter is 0.1 μm or more and 1000 μm or less.

4. The resin particles according to Claim 1, 2, or 3, wherein the coefficient of variation of the particle diameter by particle size distribution measurement is 20% or less.

5. The resin particles according to Claim 1, 2, 3, or 4, wherein the change amount of the 30% K value before and after heating when heated at 200 °C for 24 hours is 200% or less.

6. Conductive particles having the resin particles according to Claim 1, 2, 3, 4, or 5 and a conductive layer formed on the surface of the resin particles.

7. The conductive particles according to Claim 6, having an insulating material on the outer surface of the conductive layer.

8. The conductive particles according to Claim 6 or 7, having protrusions on the outer surface of the conductive layer.

9. A conductive material containing the conductive particles according to Claim 6, 7, or 8 and a binder resin.

10. 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 a connection portion connecting the first connection target member and the second connection target member, A connection structure in which the constituent material of the connection portion is the conductive particles according to Claim 6, 7, or 8, or the conductive material according to Claim 9.

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