Resin particles, metal-coated particles, and resin materials

Abstract

This invention provides resin particles capable of improving gap control of connection structures when exposed to high-temperature environments. The resin particles of this invention are resin particles of a polymer containing a polymeric component, wherein the polymeric component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. The compressive modulus of the resin particles when compressed by 20% at 200°C is 1000 N / mm². 2 above.

Description

Technical Field

[0001] This invention relates to resin particles of polymers containing polymeric components. Additionally, this invention relates to metal-coated particles and resin materials using the aforementioned resin particles. Background Technology

[0002] Conductive materials such as conductive pastes and conductive films are widely known. In recent years, development has been underway to use these conductive materials for mounting semiconductor chips and the like. From the perspective of increasing current capacity and reliability in thermal cycling, conductive materials sometimes contain conductive particles such as solder particles dispersed in the adhesive resin.

[0003] The aforementioned conductive materials have been used to obtain various connection structures. Examples of connections using these conductive materials include, for instance, connections between flexible printed circuit boards and glass substrates (FOG (Film on Glass)), connections between semiconductor chips and flexible printed circuit boards (COF (Chip on Film)), connections between semiconductor chips and glass substrates (COG (Chip on Glass)), and connections between flexible printed circuit boards and glass epoxy boards (FOB (Film on Board)).

[0004] In such a connection structure, a spacer is used as a gap control material to maintain a uniform and constant spacing between the two substrates (connected components). This spacer preferably has properties that do not damage the substrates, and furthermore, it is preferable that the spacer will not be damaged during installation. Sometimes, resin particles or metal-coated particles having resin particles and a metal coating layer covering the resin particles are used as this spacer.

[0005] As an example of the aforementioned resin particles, Patent Document 1 discloses a resin particle having a 5% weight loss temperature of 350°C or higher and a 10% K value of 100 N / mm at 25°C. 2 Above and 2500 N / mm 2 The following value, and the 30% K value at 25℃, is 100 N / mm. 2 Above and 1500 N / mm 2 the following.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: WO2021 / 193911A1 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] When conventional resin particles are used as spacers, the following problems exist: when exposed to high-temperature environments (e.g., 200°C), the compressive modulus of the resin particles cannot be sufficiently increased, thus failing to improve the gap control provided by the resin particles. Furthermore, in connection structures such as electronic components, the connection portion connecting two components is repeatedly heated and cooled (exposed to thermal cycling conditions). With conventional resin particles, thermal cycling causes the resin within the particles to thermally decompose, resulting in outgassing. In cases of significant outgassing, voids may form at the connection portion of the connection structure, or cracks and peeling may occur between the resin particles and the metal coating layer in metal-coated particles, leading to reduced conductivity reliability of the connection structure. In other words, with conventional resin particles, it is difficult to effectively control the gap between substrates and improve the conductivity reliability of the connection structure after thermal cycling when exposed to high-temperature environments.

[0011] The object of this invention is to provide resin particles capable of improving gap control of connection structures exposed to high-temperature environments, and the application of these resin particles in solder paste. Furthermore, the object of this invention is to provide metal-coated particles and resin materials using the aforementioned resin particles.

[0012] Problem Solving Methods

[0013] This specification discloses the following resin particles, the application of resin particles in solder paste, metal-coated particles, and resin materials.

[0014] Item 1. A resin particle, which is a polymeric resin particle containing a polymeric component, wherein the polymeric component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups, and the resin particle has a compressive modulus of 1000 N / mm² when compressed by 20% at 200°C. 2 above.

[0015] Item 2. The resin particles according to Item 1, wherein, in 100% by weight of the polymerizable component, the total content of the divinylbenzene and the (meth)acrylate compound having four or more (meth)acryloyl groups is 80% by weight or more.

[0016] Item 3. The resin particles according to Item 1 or 2, wherein the weight ratio of the content of the divinylbenzene in the polymerizable component to the content of the (meth)acrylate compound having four or more (meth)acryloyl groups in the polymerizable component is 0.40 or more and 1.70 or less.

[0017] Item 4. The resin particles according to any one of items 1 to 3, wherein the amount of gas released when the resin particles are heated at 250°C for 10 minutes is less than 1000 ppm.

[0018] Item 5. The resin particles according to any one of items 1 to 4, wherein the particle size of the resin particles is 1 μm or more and 100 μm or less.

[0019] Item 6. The resin particles according to any one of items 1 to 5, wherein the resin particles are used to obtain metal-coated particles having the metal coating layer by forming a metal coating layer on the surface, or the resin particles have a particle size of 5 μm or more and 100 μm or less.

[0020] Item 7. The resin particles according to Item 6, wherein the resin particles are used to obtain metal-coated particles having the metal coating by forming a metal coating layer on the surface, or the resin particles have a particle size of 20 μm or more and 100 μm or less.

[0021] Item 8. The resin particles according to any one of items 1 to 5, wherein the resin particles are used to obtain metal-coated particles having the metal coating layer by forming a metal coating layer on the surface.

[0022] Item 9. The resin particles according to Item 5, wherein the particle size of the resin particles is 5 μm or more and 100 μm or less.

[0023] Item 10. The resin particles according to Item 9, wherein the particle size of the resin particles is 20 μm or more and 100 μm or less.

[0024] Item 11. A metal-coated particle comprising: any one of items 1 to 10, a resin particle, and a metal coating layer disposed on the surface of the resin particle.

[0025] Item 12. The metal-coated particles according to Item 11, wherein the thickness of the metal coating layer is 0.2 μm or more.

[0026] Item 13. A resin material comprising an adhesive resin and resin particles of any one of items 1 to 10, or a resin material comprising an adhesive resin and metal-coated particles having the resin particles and a metal coating layer disposed on the surface of the resin particles, wherein the resin particles or the metal-coated particles are dispersed in the adhesive resin.

[0027] Item 14. The resin material according to Item 13, wherein the resin material is a solder paste containing solder particles.

[0028] Item 15. The use of the resin particles described in any one of Items 1 to 10, or the resin particles and the metal-coated particles disposed on the surface of the resin particles, in a solder paste containing solder particles and a binder resin.

[0029] The effects of the invention

[0030] The resin particles of the present invention are resin particles of a polymer containing a polymeric component. In the resin particles of the present invention, the polymeric component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. Regarding the resin particles of the present invention, the compressive modulus when the resin particles are compressed by 20% at 200°C is 1000 N / mm². 2 That's all. Regarding the resin particles of the present invention, due to the above-described configuration, the gap control of the connecting structure when exposed to high-temperature environments can be improved. Attached Figure Description

[0031] Figure 1 This is a schematic cross-sectional view of resin particles according to the first embodiment of the present invention.

[0032] Figure 2 This is a schematic cross-sectional view of a metal-coated particle using resin particles according to the first embodiment of the present invention.

[0033] Figure 3 This is a cross-sectional view showing an example of a connecting structure obtained using the resin particles of the first embodiment of the present invention.

[0034] Figure 4 This is a cross-sectional view showing an example of a connecting structure obtained using metal-coated particles, wherein the metal-coated particles are resin particles of the first embodiment of the present invention.

[0035] Symbol Explanation

[0036] 1…resin particles

[0037] 2…Metal cladding

[0038] 3… Soldering Department

[0039] 4…Resin section

[0040] 11…Metal-coated particles

[0041] 41, 51… connecting structures

[0042] 42…First connecting object component

[0043] 42a…Electrode 1

[0044] 43…Second connecting object component

[0045] 43a…Electrode 2

[0046] 44…Connecting part Detailed Implementation

[0047] The following is a detailed description of the present invention.

[0048] (Resin particles)

[0049] The resin particles of the present invention are resin particles of a polymer containing a polymeric component. In the resin particles of the present invention, the polymeric component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. In the resin particles of the present invention, the compressive modulus when the resin particles are compressed by 20% at 200°C is 1000 N / mm². 2 above.

[0050] When conventional resin particles are used as spacers, the following problem exists: when the resin particles are exposed to a high-temperature environment (e.g., 200°C), the compressive modulus of the resin particles cannot be sufficiently increased, and the gap control provided by the resin particles cannot be improved.

[0051] With respect to the resin particles of the present invention, the gap controllability of the connecting structure when exposed to high-temperature environments can be improved due to the above-described configuration. In the above-described connecting structure, the gap on or between the connecting components can be controlled with high precision using the resin particles.

[0052] Furthermore, in connection structures of electronic components, the connection points connecting two components are repeatedly heated and cooled (exposed to thermal cycling conditions). With conventional resin particles, thermal cycling causes the resin within the particles to decompose, resulting in outgassing. In cases of significant outgassing, voids may form at the connection points, or cracks and peeling may occur between the resin particles and the metal coating in metal-coated particles, reducing the conductivity reliability of the connection structure. In other words, with conventional resin particles, it is difficult to effectively control the gap between substrates and improve the conductivity reliability of the connection structure after thermal cycling when exposed to high-temperature environments.

[0053] The resin particles of the present invention, having the above-described configuration, can be used in applications requiring high conductivity. The resin particles of the present invention, having the above-described configuration, can improve the conductivity reliability of the connection structure after thermal cycling. However, it should be noted that the resin particles of the present invention can also be used in applications where high conductivity is not required.

[0054] The present invention will now be described in detail with reference to the accompanying drawings.

[0055] Figure 1 This is a schematic cross-sectional view of resin particles according to the first embodiment of the present invention.

[0056] Resin particle 1 is a polymer comprising a polymeric component. In resin particle 1, the polymeric component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. Regarding resin particle 1, the compressive modulus when resin particle 1 is compressed by 20% at 200°C is 1000 N / mm². 2 above.

[0057] The compressive modulus (K value of the resin particles at 20% of 200°C) of the above resin particles when compressed by 20% at 200°C is 1000 N / mm². 2 The above. The preferred 20% K value for the above resin particles at 200°C is 1200 N / mm. 2 The above, and more preferably, is 1300 N / mm 2 The above, and more preferably, is 1500 N / mm 2 The above, and especially preferred, is 1750 N / mm. 2 The above, and the optimal value, is 2000 N / mm. 2 The above is preferably 20000 N / mm. 2 The following, or more preferably, is 10000 N / mm 2 The following, and more preferably, is 5000 N / mm 2 The following applies: If the 20% K value of the resin particles at 200°C is above the lower limit mentioned above, the gap control of the connection structure when exposed to a high-temperature environment can be further improved. If the 20% K value of the resin particles at 200°C is below the upper limit mentioned above, the damage of the resin particles when exposed to a high-temperature environment can be further prevented.

[0058] The compression modulus (K value of the resin particles at 20% compression at 25°C) of the above-mentioned resin particles is preferably 1000 N / mm². 2 The above, and more preferably, is 1500 N / mm 2 The above, and more preferably 2000 N / mm 2 The above is preferably 20000 N / mm. 2 The following, or more preferably, is 10000 N / mm 2 The following, and more preferably, is 6000 N / mm 2The following applies: If the 20% K value of the resin particles at 25°C is above the lower limit mentioned above, the gap control of the connection structure when exposed to a high-temperature environment can be further improved. If the 20% K value of the resin particles at 25°C is below the upper limit mentioned above, the resin particles can better follow the connection object (substrate, etc.), and the gap control can be further improved.

[0059] The ratio of the compressive modulus of the resin particles when compressed by 20% at 25°C to the compressive modulus of the resin particles when compressed by 20% at 200°C is defined as (20% K value of resin particles at 25°C / 20% K value of resin particles at 200°C). This ratio (20% K value of resin particles at 25°C / 20% K value of resin particles at 200°C) is preferably 0.7 or more, more preferably 0.9 or more, further preferably 1.0 or more, preferably 3.0 or less, more preferably 2.5 or less, further preferably 2.0 or less, and particularly preferably 1.5 or less. If the ratio (20% K value of resin particles at 25°C / 20% K value of resin particles at 200°C) is at or above the lower limit and below the upper limit, the gap control of the connecting structure when exposed to high-temperature environments can be further improved.

[0060] The 20% K value of the above resin particles at 25°C and 200°C can be determined as follows.

[0061] A micro compression testing machine is used to compress resin particles under a maximum test load of 90 mN for 30 seconds at 25°C or 200°C using a smooth indenter end face of a cylindrical (50 μm diameter, diamond) indenter. The load value (N) and compression displacement (mm) are measured. The compression modulus can be calculated from the measured values ​​using the following formula. Examples of micro compression testing machines include the Fischerscope H-100 from Fischer and the ENT-5 from Elionix.

[0062] 20% K value (N / mm) 2 ) = (3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2

[0063] F: Load value (N) when resin particles undergo 20% compressive deformation.

[0064] S: Compression displacement (mm) when resin particles undergo 20% compression deformation.

[0065] R: Radius of the resin particle (mm)

[0066] As a method for adjusting the 20% K value of the above-mentioned resin particles at 25°C and 200°C, and the above-mentioned ratio (20% K value of resin particles at 25°C / 20% K value of resin particles at 200°C) to a preferred range, examples include using the preferred polymerizable component described later, adjusting the molecular weight of the polymerizable component, using the preferred crosslinking agent described later, adjusting the polymerization temperature and polymerization time, applying pressure during polymerization, adjusting the porosity (specific surface area) of the resin particles, and cleaning unreacted polymerizable components (monomers).

[0067] From the viewpoint of improving the effects of the present invention, the compression recovery rate of the above-mentioned resin particles at 25°C is preferably 20% or more, more preferably 25% or more, further preferably 30% or more, preferably 95% or less, more preferably 90% or less, and further preferably 85% or less. The compression recovery rate of the above-mentioned resin particles at 25°C may be 70% or less, 60% or less, or 55% or less.

[0068] The compression recovery rate described above can be measured as follows.

[0069] Resin particles are dispersed on the test stage. For each dispersed resin particle, a micro compression tester is used, with a smooth cylindrical (100 μm diameter, diamond) indenter end face at 25°C, applying a load (reverse load value) towards the center of the resin particle until the resin particle undergoes 40% compression deformation. Then, the load is unloaded back to the origin load value (0.40 mN). The load-compression displacement during this period can be measured, and the compression recovery rate can be calculated using the following formula. It should be noted that the loading speed is set to 0.33 mN / second. For example, the Fischerscope H-100 from Fischer and the ENT-5 from Elionix can be used as micro compression testers.

[0070] Compression recovery rate (%) = (L2 / L1) × 100

[0071] L1: The compressive displacement from the origin (load value) to the reverse load value when a load is applied.

[0072] L2: Unloading displacement from the reverse load value to the original load value during load removal.

[0073] The following provides further details regarding the resin particles. It should be noted that, in the following description, "(meth)acrylic acid" refers to one or both of "acrylic acid" and "methacrylic acid," and "(meth)acrylate" refers to one or both of "acrylate" and "methacrylate."

[0074] The aforementioned resin particles are resin particles formed from resin.

[0075] Various organic materials can be used as the resin material for the above-mentioned resin particles. Examples of resin materials for the above-mentioned resin particles include: polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as poly(methyl)acrylate and poly(isoborneol)methacrylate; polyalkylene terephthalate, polycarbonate, polyamide, phenol-formaldehyde resin, melamine-formaldehyde resin, benzoguanamine-formaldehyde resin, urea-formaldehyde resin, phenolic resin, melamine resin, benzoguanamine-formaldehyde resin, urea-formaldehyde resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene ether, polyacetal, polyimide, polyamide-imide, polyetheretherketone, polyethersulfone, and polymers obtained by polymerizing one or more polymeric monomers having olefinic unsaturated groups. Since the hardness of the resin particles can be easily controlled within a suitable range, the resin used to form the above-mentioned resin particles is preferably a polymer obtained by polymerizing one or more polymerizable monomers having multiple olefinic unsaturated groups.

[0076] The aforementioned resin particles comprise a polymer containing a polymeric component. The polymeric component preferably comprises a polymeric monomer having an olefinically unsaturated group. Examples of polymeric monomers having olefinically unsaturated groups include non-crosslinked monomers and crosslinked monomers.

[0077] Examples of non-crosslinking monomers include: styrene monomers such as styrene and α-methylstyrene; carboxyl-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; alkyl methacrylates such as (meth)acrylate, ...

[0078] Examples of monomers exhibiting the aforementioned crosslinking properties 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, etc. Multifunctional (meth)acrylate compounds such as (poly)tetramethylene glycol di(meth)acrylate and 1,4-butanediol di(meth)acrylate; silane-containing monomers such as (iso)cyanurate, triallyl trimellitate, divinylbenzene, diallyl phthalate, diallyl acrylamide, diallyl ether, γ-(meth)acryloyloxypropyltrimethoxysilane, trimethoxysilyl styrene, and vinyltrimethoxysilane.

[0079] The aforementioned polymerizable component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. The polymer of the aforementioned polymerizable component may comprise a copolymer of divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups, or it may comprise a homopolymer of divinylbenzene and a homopolymer of a (meth)acrylate compound having four or more (meth)acryloyl groups. From the viewpoint of further effectively realizing the effects of the present invention, the polymer of the aforementioned polymerizable component preferably comprises a copolymer of divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups.

[0080] The aforementioned (meth)acrylate compounds having 4 or more (meth)acryloyl groups may have 4, 5 or more, or 6 or more (meth)acryloyl groups. The aforementioned (meth)acrylate compounds having 4 or more (meth)acryloyl groups may have 20 or fewer (meth)acryloyl groups, 10 or fewer, 8 or fewer, or 6 or fewer. The range of the number of (meth)acryloyl groups in the aforementioned (meth)acrylate compounds having 4 or more (meth)acryloyl groups can be appropriately set by selecting the aforementioned lower and upper limits. The aforementioned (meth)acrylate compounds having 4 or more (meth)acryloyl groups may use only one type or a combination of two or more types.

[0081] From the viewpoint of further effectively realizing the effects of the present invention, the aforementioned (meth)acrylate compounds having four or more (meth)acryloyl groups are particularly preferably having four or more but six or fewer (meth)acryloyl groups. From the viewpoint of further effectively realizing the effects of the present invention, the aforementioned (meth)acrylate compounds having four or more (meth)acryloyl groups are preferably tetrafunctional (meth)acrylate compounds, pentafunctional (meth)acrylate compounds, or hexafunctional (meth)acrylate compounds. The aforementioned (meth)acrylate compounds having four or more (meth)acryloyl groups may include tetrafunctional (meth)acrylate compounds, may include pentafunctional (meth)acrylate compounds, or may include hexafunctional (meth)acrylate compounds.

[0082] Examples of the above-mentioned (meth)acrylate compounds having four (meth)acryloyl groups (tetrafunctional (meth)acrylate compounds) include pentaerythritol tetra(meth)acrylate, pentaerythritol alkoxytetra(meth)acrylate, alkoxylated pentaerythritol tetra(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate.

[0083] Examples of (meth)acrylate compounds having five (meth)acryloyl groups include dipentaerythritol hydroxypenta(meth)acrylate and alkoxylated dipentaerythritol hydroxypenta(meth)acrylate.

[0084] Examples of (meth)acrylate compounds having six (meth)acryloyl groups include dipentaerythritol hexa(meth)acrylate (such as dipentaerythritol hexaacrylate) and alkoxylated dipentaerythritol hexa(meth)acrylate (such as alkoxylated dipentaerythritol hexaacrylate).

[0085] From the viewpoint of further effectively realizing the effects of the present invention, the aforementioned (meth)acrylate compound having four or more (meth)acryloyl groups preferably comprises a (meth)acrylate compound having four (meth)acryloyl groups, more preferably comprising pentaerythritol tetra(meth)acrylate. From the viewpoint of further effectively realizing the effects of the present invention, the aforementioned polymerizable component preferably comprises divinylbenzene and a (meth)acrylate compound having four (meth)acryloyl groups, more preferably comprising divinylbenzene and pentaerythritol tetra(meth)acrylate. From the viewpoint of further effectively realizing the effects of the present invention, the polymer (resin particles) of the aforementioned polymerizable component preferably comprises a copolymer of divinylbenzene and a (meth)acrylate compound having four (meth)acryloyl groups, more preferably comprising a copolymer of divinylbenzene and pentaerythritol tetra(meth)acrylate.

[0086] The aforementioned polymerizable components may include polymerizable components other than divinylbenzene and (meth)acrylate compounds having four or more (meth)acryloyl groups (hereinafter, sometimes referred to as "other polymerizable components"), or may not include them.

[0087] Other polymerizable components mentioned above include polymerizable monomers having olefinic unsaturated groups. Only one of these other polymerizable components may be used, or two or more may be used in combination.

[0088] When resin particles are obtained using the aforementioned crosslinking monomers, a crosslinking agent can be used. Examples of such crosslinking agents include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Only one type of crosslinking agent may be used, or two or more may be used in combination.

[0089] From the viewpoint of further effectively realizing the effects of the present invention, the polymerizable component preferably includes a crosslinking agent. From the viewpoint of further effectively realizing the effects of the present invention, the polymerizable component (the crosslinking agent) preferably includes (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, or 1,4-butanediol di(meth)acrylate. From the viewpoint of further effectively realizing the effects of the present invention, the polymerizable component (the crosslinking agent) is preferably (poly)propylene glycol di(meth)acrylate, (poly)tetramethylene glycol di(meth)acrylate, or 1,4-butanediol di(meth)acrylate.

[0090] The aforementioned resin particles can be obtained by polymerizing the polymerizable monomers having olefinic unsaturated groups using known methods. Examples of such methods include suspension polymerization in the presence of a free radical polymerization initiator, and methods that use non-crosslinked seed particles together with a free radical polymerization initiator to swell and polymerize the monomers.

[0091] The viscosity of the mixture of the above-mentioned polymerizable components (before polymerization) is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, further preferably 500 mPa·s or more, particularly preferably 1000 mPa·s or more, most preferably 1200 mPa·s or more, preferably 7000 mPa·s or less, more preferably 5000 mPa·s or less, and further preferably 4000 mPa·s or less. If the viscosity of the mixture of the above-mentioned polymerizable components (before polymerization) is at or above the lower limit, the particle size of the resin particles can be easily controlled. If the viscosity of the mixture of the above-mentioned polymerizable components (before polymerization) is at or below the upper limit, the molecular weight of the polymer of the obtained polymerizable components can be increased, the 20% K value of the resin particles at 25°C and 200°C can be easily adjusted to a preferred range, and the gap control of the connected structure when exposed to high-temperature environments can be further improved. The mixture of the above-mentioned polymerizable components (before polymerization) contains a polymerizable compound for the resin particles in a weight ratio for the resin particles.

[0092] The viscosity of the mixture of the above-mentioned polymerizable components (before polymerization) can be measured, for example, using an E-type viscometer at 25°C and 5 rpm. Examples of such an E-type viscometer include the "VISCOMETER TV-22" manufactured by Toki Sangyo Co., Ltd.

[0093] The particle size of the aforementioned resin particles is preferably 0.1 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, even more preferably 2 μm or more, even more preferably 5 μm or more, particularly preferably 10 μm or more, most preferably 20 μm or more, preferably 300 μm or less, more preferably 100 μm or less, further preferably 70 μm or less, particularly preferably 50 μm or less, and most preferably 30 μm or less. If the particle size of the aforementioned resin particles is at or above the aforementioned lower limit, it is difficult for agglomeration to occur when a metal coating layer is formed on the surface of the resin particles by chemical plating, and it is not easy to form agglomerated metal-coated particles. If the particle size of the aforementioned resin particles is below the aforementioned upper limit, the gap control of the connecting structure when exposed to a high-temperature environment can be further improved.

[0094] In particular, since the occurrence of cracks in the cured product can be suppressed when the resin material using resin particles is cured, and the gap control in the connection structure using the resin material can be significantly improved when exposed to a high-temperature environment, the particle size of the resin particles is preferably 5 μm or more. To further enhance this effect, the particle size of the resin particles is more preferably 10 μm or more, and even more preferably 20 μm or more. Furthermore, when the resin material is solder paste, this effect is further enhanced. The particle size of the resin particles is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 20 μm or more and 100 μm or less. Moreover, from the viewpoint of significantly improving the conductivity reliability of the connection structure after thermal cycling, the particle size of the resin particles is preferably 10 μm or more.

[0095] The inventors have discovered that, in order to further and more effectively realize the effects of the present invention, it is important to combine the following three elements, which include: 1) using a specific polymerizable component; 2) controlling the compressive modulus of the resin particles within a specific range; and 3) controlling the particle size of the resin particles within a specific range.

[0096] The particle size of the resin particles mentioned above refers to the diameter when the resin particles are perfectly spherical, and to the diameter when the resin particles are not perfectly spherical, assuming they are spheres with a volume equivalent to that of the particles.

[0097] The particle size of the aforementioned resin particles is preferably the average particle size, and more preferably the number-average particle size. Furthermore, by ensuring that the lower and upper limits of the number-average particle size of the resin particles satisfy the preferred lower and upper limits of the particle size of the resin particles, the effect can be further enhanced. The particle size of the resin particles can be determined, for example, by observing any 50 resin particles using an electron microscope or an optical microscope and calculating the average particle size of each resin particle, or by performing laser diffraction particle size distribution measurement. When observing using an electron microscope or an optical microscope, the particle size of each resin particle is determined in terms of the equivalent circle diameter. When observing using an electron microscope or an optical microscope, the average particle size of any 50 resin particles, measured in terms of the equivalent circle diameter, is substantially equal to the average particle size measured in terms of the equivalent sphere diameter. In laser diffraction particle size distribution measurement, the particle size of each resin particle is determined in terms of the equivalent sphere diameter. The particle size of the aforementioned resin particles is preferably calculated by laser diffraction particle size distribution measurement.

[0098] From the viewpoint of further controlling the gap on or between the connected components with higher precision, the aforementioned resin particles preferably do not contain resin particles with a particle size of 1.5 times or more than the average particle size, or contain resin particles with a particle size of 1.5 times or more than the average particle size at a concentration of 1000 ppm or less. From the viewpoint of further controlling the gap on or between the connected components with higher precision, the content of resin particles with a particle size of 1.5 times or more than the average particle size is preferably 1000 ppm or less, more preferably 100 ppm or less, further preferably 10 ppm or less, and particularly preferably 0.1 ppm or less. This range includes 0 ppm. From the viewpoint of further controlling the gap on or between the connected components with higher precision, the content of resin particles with a particle size of 1.5 times or more than the average particle size is most preferably 0 ppm (not contained).

[0099] The content (ppm) of resin particles with a particle size greater than 1.5 times the average particle size can be determined as follows: The resin particles are filtered through a filter with a pore size 1.5 times the average particle size. The resin particles remaining on the filter are observed using an optical microscope, and the resin particles with a particle size greater than 1.5 times the average particle size are counted. The content (ppm) of resin particles with a particle size greater than 1.5 times the average particle size is calculated by dividing the counted resin particles by the total number of filtered resin particles.

[0100] From the viewpoint of further improving the precision of controlling the gap on or between connected components, the coefficient of variation (CV) of the resin particle size is preferably 10% or less, more preferably 8.0% or less. There is no particular limitation on the lower limit of the CV of the resin particle size. The CV of the resin particle size can be 0% or more, or 1.0% or more. The range of the CV of the resin particle size can be appropriately set by selecting the aforementioned lower limit and upper limit.

[0101] The CV value (coefficient of variation) of the particle size of the above resin particles can be determined as follows.

[0102] The CV value (%) of resin particle size = (ρ / Dn) × 100

[0103] ρ: Standard deviation of resin particle size

[0104] Dn: Average particle size of resin particles

[0105] From the viewpoint of further improving the precision control of the gap between or on the connecting components, the aspect ratio of the resin particles is preferably 1.5 or less, more preferably 1.3 or less. There is no particular limitation on the lower limit of the aspect ratio of the resin particles. The aspect ratio of the resin particles can be 1.0 or more, or 1.1 or more. The aspect ratio represents the length / short diameter. The aspect ratio is preferably determined by observing 10 arbitrary resin particles using an electron microscope or an optical microscope, taking the maximum and minimum diameters as the length and short diameters respectively, and calculating the average length / short diameter ratio of each spherical resin particle. The range of the aspect ratio of the resin particles can be appropriately set by selecting the lower and upper limits mentioned above.

[0106] The gas release rate of the resin particles after heating at 250°C for 10 minutes is preferably 2000 ppm or less, more preferably 1000 ppm or less, further preferably 800 ppm or less, particularly preferably 500 ppm or less, and most preferably 300 ppm or less. This range includes 0 ppm. The most preferably gas release rate of the resin particles after heating at 250°C for 10 minutes is 0 ppm (no gas release). If the gas release rate of the resin particles after heating at 250°C for 10 minutes is below the above upper limit, it is possible to suppress the formation of voids at the joint of the connecting structure due to thermal cycling, and the formation of cracks and peeling between the resin particles and the metal coating layer in the metal-coated particles, thereby improving the conductivity reliability of the connecting structure after thermal cycling. The lower limit of the gas release rate of the resin particles after heating at 250°C for 10 minutes is not particularly limited. The gas release rate of the resin particles after heating at 250°C for 10 minutes can be 0 ppm or more, 5 ppm or more, or 10 ppm or more. The range of gas release when the above resin particles are heated at 250°C for 10 minutes can be set by appropriately selecting the above lower limit and the above upper limit.

[0107] The amount of gas released when the above resin particles are heated at 250°C for 10 minutes can be measured, for example, as described below.

[0108] As samples, 5 mg of the aforementioned resin particles and a known weight of toluene (a toluene solution of known concentration) were prepared. Using a thermal desorption apparatus, the 5 mg of resin particles were heated at 250°C for 10 minutes while helium was introduced at a flow rate of 20 mL / min, causing the resulting component (A) to be adsorbed and captured in a glass tube filled with adsorbent. Helium was then introduced into the glass tube containing component (A), and the tube was heated at 350°C for 40 minutes. The component released from the adsorbent was directly introduced into a gas chromatograph-mass spectrometer for analysis. Using a thermal desorption apparatus, the known weight of toluene was heated at 250°C for 10 minutes while helium was introduced at a flow rate of 20 mL / min, causing the resulting component (B) to be adsorbed and captured in a glass tube filled with adsorbent. Helium gas was introduced into the glass tube containing the captured component (B), and the glass tube containing the captured component (B) was heated at 350°C for 40 minutes. The component detached from the adsorbent was directly introduced into a gas chromatograph-mass spectrometer for analysis. The peak area values ​​of each component detected using the resin particles were compared with the peak area values ​​detected using a known weight of toluene, and the amount of gas released when the resin particles were heated at 250°C for 10 minutes was calculated.

[0109] The known weight of toluene mentioned above can be 5 mg of toluene.

[0110] More specifically, the amount of gas released when the above-mentioned resin particles are heated at 250°C for 10 minutes can be measured as follows.

[0111] The sample (5 mg of resin particles or a known weight of toluene) was sealed in a sample tube, and helium gas was introduced into the sample tube at a flow rate of 20 mL / min while heating at 250°C for 10 minutes. The components volatilized due to heating were adsorbed and captured in a glass tube filled with a capturing agent (e.g., TENAX-TA). Helium gas was then introduced into the glass tube containing the captured volatilized components while heating the glass tube at 350°C for 40 minutes. The components that were released from the adsorbent due to heating were directly introduced into a gas chromatograph-mass spectrometer (hereinafter, GC / MS) for analysis (ATD-GC / MS). Examples of the apparatus used for the above determination and the analytical conditions are described below.

[0112] [ATD-GC / MS]

[0113] Heated desorption unit: PerkinElmer "TurboMatrix350"

[0114] GC: Agilent Technologies' "7890A"

[0115] MS: "JMS-Q1000GCQ" manufactured by JEOL Ltd.

[0116] Column: "EQUITY-1 60m × 0.25mm I.D. × 0.25μm" manufactured by SUPELCO

[0117] <Conditions of the thermal desorption device>

[0118] Heating temperature of the sample tube: 250 °C

[0119] Heating time: 10 minutes

[0120] Flow rate of helium: 20 mL / minute

[0121] Cold trap temperature: 4 °C

[0122] Desorption temperature and time from the capture tube (glass tube): 350 °C and 40 minutes

[0123] Split: Inlet; 25 mL / minute, Outlet; 25 mL / minute

[0124] <GC / MS conditions>

[0125] Carrier gas: Helium, contact gas flow

[0126] Column flow rate: 1.5 mL

[0127] Split ratio: 1:30

[0128] Initial oven temperature: 40 °C

[0129] Hold time: 4 minutes

[0130] Temperature ramp rate: 10 °C / minute

[0131] Final temperature: 300 °C

[0132] Hold time: 10 minutes

[0133] MS: EI mode, 70 eV, Transfer line; 250 °C, Ion source; 230 °C

[0134] The sum of the peak area values of each component detected when the above resin particles were used was compared with the peak area values detected when a toluene solution of a known concentration (toluene of a known weight, for example, "VOCs Mixed Standard Stock Solution III" manufactured by Kanto Chemical Co., Inc.) was used. Thus, the concentration of volatile components (degassing) from the resin particles was calculated in terms of toluene. In the present invention, the amount of degassing (ppm) of the resin particles when heated at 250 °C for 10 minutes was calculated by the following formula.

[0135] Gas release (ppm) = [(sum of peak areas of volatile components from resin particles) / (peak area of ​​toluene) × concentration of toluene in toluene solution (μg / g) × volume of toluene solution measured (g)] / weight of resin particles

[0136] Methods for adjusting the gas release rate of the resin particles after heating at 250°C for 10 minutes to a preferred range include: using the preferred polymerizable component described above, adjusting the molecular weight of the polymerizable component, using the preferred crosslinking agent described above, adjusting the polymerization temperature and polymerization time, applying pressure during polymerization, and cleaning unreacted polymerizable components (monomers).

[0137] The uses of the aforementioned resin particles are not particularly limited. The aforementioned resin particles are suitable for various applications. The aforementioned resin particles are preferably used as spacers. The aforementioned resin particles are preferably spacer resin particles. The aforementioned resin particles can also be used as spacers in resin materials. Examples of such spacers include spacers for liquid crystal display elements, spacers for gap control, and spacers for stress relief. The aforementioned gap control spacers can be used for gap control of stacked chips to ensure stand-off height and flatness, and for gap control of optical components to ensure the smoothness of the glass surface and the thickness of the adhesive layer. The aforementioned stress relief spacers can be used for stress relief of sensor chips, and for stress relief of adhesive layers bonding two adhered objects.

[0138] The aforementioned resin particles are preferably used as spacers for liquid crystal display elements, and more preferably as peripheral sealants for liquid crystal display elements. In the aforementioned peripheral sealants for liquid crystal display elements, the resin particles preferably function as spacers. Because the resin particles have good compression set characteristics, when they are used as spacers and disposed between substrates, they can be effectively disposed between the substrates. Furthermore, since the resin particles can suppress scratches on components of the liquid crystal display element, display defects are less likely to occur in liquid crystal display elements using the aforementioned spacers.

[0139] Furthermore, the aforementioned resin particles are also suitable for use as inorganic fillers, additives to colorants, shock absorbers, or vibration absorbers. For example, the aforementioned resin particles can be used as a substitute for rubber or springs. Additionally, the aforementioned resin particles can be used to obtain the metal-coated particles described later.

[0140] In the aforementioned 100% by weight of resin particles, the content of the polymer of the polymeric component is preferably 80% by weight or more, more preferably 85% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more. If the content of the polymer of the polymeric component is at or above the aforementioned lower limit, the 20% K value of the resin particles at 25°C and 200°C can be easily adjusted to a preferred range, further improving the gap control of the connected structure when exposed to high-temperature environments. In the aforementioned 100% by weight of resin particles, the upper limit of the content of the polymer of the polymeric component is not particularly limited. In the aforementioned 100% by weight of resin particles, the content of the polymer of the polymeric component can be 100% by weight (total amount) or less, or less than 100% by weight. In the aforementioned 100% by weight of resin particles, the range of the content of the polymer of the polymeric component can be appropriately set by selecting the aforementioned lower limit and the aforementioned upper limit.

[0141] Of the 100% by weight of the polymerizable component described above, the content of divinylbenzene is preferably 20% by weight or more, more preferably 25% by weight or more, further preferably 30% by weight or more, particularly preferably 40% by weight or more, most preferably 45% by weight or more, preferably 80% by weight or less, more preferably 75% by weight or less, further preferably 70% by weight or less, particularly preferably 65% ​​by weight or less, and most preferably 60% by weight or less. If the content of divinylbenzene is above or below the lower limit and below the upper limit, the effects of the present invention can be further effectively achieved, and the conductivity reliability of the connecting structure after thermal cycling can be further improved. If the content of divinylbenzene is above the lower limit, the heat resistance of the resin particles can be improved. If the content of divinylbenzene is below the upper limit, the residual amount of unreacted polymerizable component (monomer) can be reduced.

[0142] Of the 100% by weight of the polymerizable component described above, the content of the (meth)acrylate compound having four or more (meth)acryloyl groups is preferably 20% by weight or more, more preferably 25% by weight or more, even more preferably 30% by weight or more, even more preferably 35% by weight or more, particularly preferably 40% by weight or more, most preferably 45% by weight or more, preferably 80% by weight or less, more preferably 75% by weight or less, even more preferably 70% by weight or less, even more preferably 65% ​​by weight or less, even more preferably 60% by weight or less, particularly preferably 55% by weight or less, and most preferably 50% by weight or less. If the content of the (meth)acrylate compound having four or more (meth)acryloyl groups is above the lower limit and below the upper limit, the effects of the present invention can be further effectively achieved, and the conductivity reliability of the connecting structure after thermal cycling can be further improved. If the content of the (meth)acrylate compound having four or more (meth)acryloyl groups is above the lower limit, the crosslinking degree of the resin particles can be improved. If the content of the above-mentioned (meth)acrylate compounds having four or more (meth)acryloyl groups is below the above-mentioned upper limit, the heat resistance of the resin particles can be improved.

[0143] In the above-mentioned 100% by weight of polymerizable components, the total content of the above-mentioned divinylbenzene and the above-mentioned (meth)acrylate compound having four or more (meth)acryloyl groups is preferably 80% by weight or more, more preferably 85% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more. If the total content of the above-mentioned divinylbenzene and the above-mentioned (meth)acrylate compound having four or more (meth)acryloyl groups is at or above the above-mentioned lower limit, the effects of the present invention can be further effectively exerted. The upper limit of the total content of the above-mentioned divinylbenzene and the above-mentioned (meth)acrylate compound having four or more (meth)acryloyl groups is not particularly limited. In the above-mentioned 100% by weight of polymerizable components, the total content of the above-mentioned divinylbenzene and the above-mentioned (meth)acrylate compound having four or more (meth)acryloyl groups can be 100% by weight (total amount) or less, or less than 100% by weight. In the above-mentioned polymerizable component 100% by weight, the range of the total content of the above-mentioned divinylbenzene and the above-mentioned (meth)acrylate compound having 4 or more (meth)acryloyl groups can be appropriately set by selecting the above-mentioned lower limit value and the above-mentioned upper limit value.

[0144] The weight ratio of the content of divinylbenzene in the polymerizable component to the content of the (meth)acrylate compound having four or more (meth)acryloyl groups in the polymerizable component is defined as the weight ratio (content of divinylbenzene / content of (meth)acrylate compound having four or more (meth)acryloyl groups). The weight ratio (content of divinylbenzene / content of (meth)acrylate compound having four or more (meth)acryloyl groups) is preferably 0.30 or more, more preferably 0.40 or more, even more preferably 0.50 or more, even more preferably 0.60 or more, particularly preferably 0.70 or more, most preferably 0.80 or more, preferably 10.00 or less, more preferably 5.00 or less, even more preferably 4.00 or less, even more preferably 3.00 or less, particularly preferably 2.00 or less, and most preferably 1.50 or less. If the above weight ratio (content of divinylbenzene / content of (meth)acrylate compounds having 4 or more (meth)acryloyl groups) is above the lower limit and below the upper limit, the effects of the present invention can be further effectively achieved. If the above weight ratio (content of divinylbenzene / content of (meth)acrylate compounds having 4 or more (meth)acryloyl groups) is above the lower limit, the heat resistance of the resin particles can be improved. If the above weight ratio (content of divinylbenzene / content of (meth)acrylate compounds having 4 or more (meth)acryloyl groups) is below the upper limit, the degree of crosslinking of the resin particles can be improved, and the residual amount of unreacted polymerizable components (monomers) can be reduced.

[0145] (Metal-coated particles)

[0146] The metal-coated particles of the present invention comprise the aforementioned resin particles and a metal coating layer disposed on the surface of the aforementioned resin particles. In the metal-coated particles of the present invention, due to the aforementioned configuration, when the metal-coated particles are used as spacers, the gap controllability of the connection structure exposed to high-temperature environments can be improved, and the conductivity reliability of the connection structure after thermal cycling can be improved.

[0147] In particular, it is preferable that the resin particles are used to obtain metal-coated particles having the aforementioned metal coating layer by forming a metal coating layer on the surface, or that the resin particles have a particle size of 5 μm or more and 100 μm or less. In this case, when the resin material using the resin particles or metal-coated particles cures, the occurrence of cracks in the cured product can be suppressed, and the gap control in the connection structure using the resin material can be significantly improved when exposed to a high-temperature environment. Furthermore, the conductivity reliability of the connection structure after thermal cycling can be significantly improved. Since these effects can be further effectively achieved, it is more preferable that the resin particles are used to obtain metal-coated particles having the aforementioned metal coating layer by forming a metal coating layer on the surface, or that the resin particles have a particle size of 10 μm or more and 100 μm or less. Since these effects can be further effectively achieved, it is even more preferable that the resin particles are used to obtain metal-coated particles having the aforementioned metal coating layer by forming a metal coating layer on the surface, or that the resin particles have a particle size of 20 μm or more and 100 μm or less.

[0148] In particular, the aforementioned resin particles are preferably used to obtain metal-coated particles having the aforementioned metal coating layer by forming a metal coating layer on the surface (the use of the aforementioned resin particles to obtain metal-coated particles having the aforementioned metal coating layer by forming a metal coating layer on the surface). In this case, when the resin material using the metal-coated particles cures, the occurrence of cracks in the cured product can be suppressed, and the gap control in the connection structure using the resin material can be significantly improved when exposed to a high-temperature environment. Furthermore, the conductivity reliability of the connection structure after thermal cycling can be significantly improved.

[0149] Figure 2 This is a schematic cross-sectional view of a metal-coated particle using resin particles according to the first embodiment of the present invention.

[0150] Figure 2 The metal-coated particle 11 shown has a resin particle 1 and a metal coating layer 2 disposed on the surface of the resin particle 1. The metal coating layer 2 covers the surface of the resin particle 1. The metal-coated particle 11 is a coated particle formed by coating the surface of the resin particle 1 with the metal coating layer 2.

[0151] The compression modulus (K value of the metal-coated particles at 200°C with 20% compression) is preferably 1000 N / mm². 2 The above, and more preferably, is 1500 N / mm 2 The above, and more preferably 2000 N / mm 2 The above is preferably 20000 N / mm. 2The following, or more preferably, is 10000 N / mm 2 The following, and more preferably, is 6000 N / mm 2 The following applies: If the 20% K value of the aforementioned metal-coated particles at 200°C is above the lower limit, the gap control of the connecting structure when exposed to high-temperature environments can be further improved. If the 20% K value of the aforementioned metal-coated particles at 200°C is below the upper limit, the damage of the metal-coated particles of the connecting structure when exposed to high-temperature environments can be further prevented.

[0152] The compression modulus (K value of the metal-coated particles at 20% compression at 25°C) when the above-mentioned metal-coated particles are compressed by 20% is preferably 1500 N / mm². 2 The above, and more preferably, is 2000 N / mm 2 The above, and more preferably 2500 N / mm 2 The above is preferably 20000 N / mm. 2 The following, and more preferably, is 15000 N / mm 2 The following, and more preferably, is 8000 N / mm 2 The following applies: If the 20% K value of the aforementioned metal-coated particles at 25°C is above the lower limit, the gap control of the connection structure when exposed to high-temperature environments can be further improved. If the 20% K value of the aforementioned metal-coated particles at 25°C is below the upper limit, the aforementioned metal-coated particles can better follow the connected component (substrate, etc.), and the gap control can be further improved.

[0153] The ratio of the compressive modulus of the aforementioned metal-coated particles when compressed by 20% at 25°C to the compressive modulus of the aforementioned metal-coated particles when compressed by 20% at 200°C is defined as (20% K value of metal-coated particles at 25°C / 20% K value of metal-coated particles at 200°C). This ratio (20% K value of metal-coated particles at 25°C / 20% K value of metal-coated particles at 200°C) is preferably 0.7 or more, more preferably 0.9 or more, further preferably 1.0 or more, preferably 3.0 or less, more preferably 2.5 or less, and further preferably 2.0 or less. If the ratio (20% K value of metal-coated particles at 25°C / 20% K value of metal-coated particles at 200°C) is at or above the lower limit and below the upper limit, the gap controllability of the connecting structure when exposed to high-temperature environments can be further improved.

[0154] The 20% K value of the aforementioned metal-coated particles at 25°C and 200°C can be determined as follows.

[0155] Using a micro compression testing machine, metal-coated particles are compressed under a maximum test load of 90 mN for 30 seconds at 25°C or 100°C using a smooth indenter end face of a cylindrical cylinder (50 μm in diameter, made of diamond). The load value (N) and compression displacement (mm) are measured. The compression modulus can be calculated from the measured values ​​using the following formula. Examples of micro compression testing machines include the Fischerscope H-100 from Fischer and the ENT-5 from Elionix.

[0156] 20% K value (N / mm) 2 ) = (3 / 2 1 / 2 )·F·S -3 / 2 ·R -1 / 2

[0157] F: Load value (N) when the metal-coated particles undergo 20% compressive deformation.

[0158] S: Compressive displacement (mm) when the metal-coated particles undergo 20% compressive deformation.

[0159] R: Radius of the metal-coated particle (mm)

[0160] From the viewpoint of making the present invention more effective, the compression recovery rate of the above-mentioned metal-coated particles at 25°C is preferably 20% or more, more preferably 25% or more, further preferably 30% or more, preferably 95% or less, more preferably 90% or less, and further preferably 85% or less.

[0161] The compression recovery rate described above can be measured as follows.

[0162] Metal-coated particles are dispersed on the test stage. For each dispersed metal-coated particle, a micro compression tester is used. A load (reverse load value) is applied to the center of the metal-coated particle at 25°C using the smooth end face of a cylindrical (100 μm diameter, diamond) indenter until the metal-coated particle undergoes 40% compressive deformation. Then, the load is unloaded until the original load value (0.40 mN) is applied. The load-compression displacement during this period can be measured, and the compression recovery rate can be calculated using the following formula. It should be noted that the loading speed is set to 0.33 mN / second. For example, the Fischerscope H-100 from Fischer and the ENT-5 from Elionix can be used as micro compression testers.

[0163] Compression recovery rate (%) = (L2 / L1) × 100

[0164] L1: The compressive displacement from the origin (load value) to the reverse load value when a load is applied.

[0165] L2: Unloading displacement from the reverse load value to the original load value during load removal.

[0166] The particle size of the aforementioned metal-coated particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 2 μm or more, further preferably 5 μm or more, particularly preferably 10 μm or more, most preferably 20 μm or more, preferably 300 μm or less, more preferably 100 μm or less, further preferably 70 μm or less, particularly preferably 50 μm or less, and most preferably 30 μm or less. If the particle size of the metal-coated particles is above or below the aforementioned lower limit and below the aforementioned upper limit, then when forming the metal coating layer, it is not easy to form agglomerated metal-coated particles, the spacing between the substrates (connected components) will not become too large, and the metal coating layer is not easily peeled off from the surface of the resin particles.

[0167] In particular, since the occurrence of cracks in the cured resin material using metal-coated particles can be suppressed during curing, and the gap control in the connection structure using the resin material can be significantly improved when exposed to a high-temperature environment, the particle size of the aforementioned metal-coated particles is preferably 5 μm or more. Since these effects can be further effectively achieved, the particle size of the aforementioned metal-coated particles is more preferably 10 μm or more, and even more preferably 20 μm or more. Furthermore, when the aforementioned resin material is solder paste, these effects can be further effectively achieved. The particle size of the aforementioned metal-coated particles is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 20 μm or more and 100 μm or less. Moreover, from the viewpoint of significantly improving the conductivity reliability of the connection structure after thermal cycling, the particle size of the aforementioned metal-coated particles is preferably 10 μm or more.

[0168] The inventors have discovered that, in order to further and more effectively realize the effects of the present invention, it is important to combine the following three elements, which include: 1) using a specific polymerizable component for the resin particles; 2) controlling the compressive modulus of the resin particles in the metal-coated particles within a specific range; and 3) controlling the particle size of the metal-coated particles within a specific range.

[0169] The particle size of the aforementioned metal-coated particles is expressed as the diameter when the metal-coated particles are perfectly spherical, and as the diameter when the metal-coated particles are not perfectly spherical, it is expressed as the diameter when they are assumed to be perfectly spherical with a volume equivalent to that of the particle.

[0170] The particle size of the aforementioned metal-coated particles is preferably the average particle size, and more preferably the number-average particle size. Furthermore, by ensuring that the lower and upper limits of the number-average particle size of the aforementioned metal-coated particles satisfy the preferred lower and upper limits of the particle size of the aforementioned metal-coated particles, the effect can be further enhanced. The particle size of the metal-coated particles can be determined, for example, by observing any 50 metal-coated particles using an electron microscope or an optical microscope and calculating the average particle size of each metal-coated particle, or by performing laser diffraction particle size distribution measurement. When observing using an electron microscope or an optical microscope, the particle size of each metal-coated particle is determined in terms of the equivalent circle diameter. When observing using an electron microscope or an optical microscope, the average particle size of any 50 metal-coated particles, measured in terms of the equivalent circle diameter, is substantially equal to the average particle size measured in terms of the equivalent sphere diameter. In laser diffraction particle size distribution measurement, the particle size of each metal-coated particle is determined in terms of the equivalent sphere diameter. The particle size of the aforementioned metal-coated particles is preferably calculated by laser diffraction particle size distribution measurement.

[0171] The metal used to form the aforementioned metal cladding layer is not particularly limited. Examples of such 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 their alloys. Additionally, examples of such metals include tin-doped indium oxide (ITO) and solder. From the viewpoint of further improving the reliability of the connection between electrodes, the aforementioned metal is preferably a tin-containing alloy, nickel, palladium, copper, or gold, with nickel or palladium being more preferred.

[0172] Like the metal-coated particle 11, the aforementioned metal coating layer can be formed from a single layer. Alternatively, the aforementioned metal coating layer can be formed from multiple layers. That is, the aforementioned metal coating layer can have a stacked structure of two or more layers. When the metal coating layer is formed from multiple 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 more preferably a gold layer. When the outermost layer is one of these preferred metal coating layers, the reliability of the connection between electrodes can be further improved. Furthermore, when the outermost layer is a gold layer, corrosion resistance can be further improved.

[0173] There is no particular limitation on the method for forming a metal coating layer on the surface of the aforementioned resin particles. Examples of methods for forming the metal coating layer include electroless plating, electroplating, physical vapor deposition, and applying metal powder or a paste containing metal powder and a binder to the surface of the resin particles. From the viewpoint of more easily forming a metal coating layer, electroless plating is preferred. Examples of physical vapor deposition methods include vacuum vapor deposition, ion plating, and ion sputtering.

[0174] The thickness of the aforementioned metal cladding layer is preferably 0.005 μm or more, more preferably 0.01 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, particularly preferably 0.15 μm or more, most preferably 0.2 μm or more, preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 0.3 μm or less. The thickness of the aforementioned metal cladding layer is the overall thickness of the metal cladding layer when there are multiple layers. If the thickness of the aforementioned metal cladding layer is above or below the aforementioned lower limit and below the aforementioned upper limit, the metal cladding particles will not become too hard, and the metal cladding particles will deform sufficiently between the substrate (connected components). In particular, when the thickness of the aforementioned metal cladding layer is 0.2 μm or more, the effects of the present invention can be further effectively achieved, and the conductivity reliability of the connection structure after thermal cycling can be further improved.

[0175] When the aforementioned metal cladding layer is formed of multiple layers, the thickness of the outermost metal cladding layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, preferably 0.5 μm or less, more preferably 0.1 μm or less. If the thickness of the outermost metal cladding layer is above or below the aforementioned lower limit and below the aforementioned upper limit, the coating of the outermost metal cladding layer becomes more uniform, the corrosion resistance is sufficiently increased, and the connection reliability between electrodes can be further improved. In addition, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

[0176] The thickness of the aforementioned metal cladding layer can be measured, for example, by observing the cross-section of the metal-clad particles using a transmission electron microscope (TEM). For the thickness of the aforementioned metal cladding layer, it is preferable to calculate the average thickness of the metal cladding layer at any five locations as the thickness of the metal cladding layer for one metal-clad particle; more preferably, the average thickness of the entire metal cladding layer can be calculated as the thickness of the metal cladding layer for one metal-clad particle. The thickness of the aforementioned metal cladding layer is preferably determined by calculating the average thickness of the metal cladding layer for any 50 metal-clad particles. The thickness of the aforementioned metal cladding layer is preferably the average thickness.

[0177] (Resin material)

[0178] The resin material of the present invention is a resin material comprising the above-described resin particles and adhesive resin, or a resin material comprising the above-described resin particles and a metal-coated layer disposed on the surface of the resin particles, and an adhesive resin. In the resin material of the present invention, the above-described resin particles or the above-described metal-coated particles are dispersed in the above-described adhesive resin. In the resin material of the present invention, due to the above-described configuration, the gap control of the connection structure when exposed to a high-temperature environment can be improved, and the conductivity reliability of the connection structure after thermal cycling can be improved.

[0179] The aforementioned resin material preferably further comprises conductive particles. The aforementioned resin material preferably further comprises conductive particles different from the aforementioned metal-coated particles. The aforementioned conductive particles are different from the aforementioned resin particles. The aforementioned resin material is preferably a conductive material that further comprises conductive particles. The aforementioned resin material is preferably a conductive material. When the aforementioned resin material is a conductive material, it is suitable for electrical connections between electrodes. The aforementioned resin material is preferably a circuit connection material. When the aforementioned resin material further comprises conductive particles, it can be used as a conductive paste and a conductive film, etc. When the resin material of the present invention is a conductive film, a film without conductive particles can be laminated on a conductive film containing conductive particles. The aforementioned conductive paste is preferably an isotropic conductive paste. The aforementioned conductive film is preferably an isotropic conductive film.

[0180] The aforementioned resin particles are preferably used in conjunction with conductive particles, and more preferably with solder particles. The aforementioned metal-coated particles are preferably used in conjunction with conductive particles, and more preferably with solder particles. The aforementioned resin material preferably comprises the aforementioned resin particles or the aforementioned metal-coated particles and the aforementioned conductive particles, and more preferably comprises the aforementioned resin particles or the aforementioned metal-coated particles and the aforementioned solder particles. The aforementioned metal-coated particles are preferably different from the solder particles, and preferably do not contain solder. By using the aforementioned conductive particles (solder particles, etc.) differently from the aforementioned resin particles or the aforementioned metal-coated particles, the effects of the present invention can be further effectively achieved, and the conductivity reliability of the connection structure after thermal cycling can be further improved.

[0181] In addition, the following invention is also disclosed in this specification: the application of the above-described resin particles, or the above-described resin particles and metal-coated particles disposed on the surface of the above-described resin particles, in solder paste containing solder particles and binder resin.

[0182] In 100% by weight of the aforementioned resin material (solder paste), the content of the aforementioned resin particles or the aforementioned metal-coated particles is preferably 0.1% by weight or more, more preferably 1% by weight or more, further preferably 2% by weight or more, particularly preferably 5% by weight or more, most preferably 10% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, and further preferably 50% by weight or less. If the content of the aforementioned resin particles or the aforementioned metal-coated particles is above the aforementioned lower limit and below the aforementioned upper limit, the effects of the present invention can be further effectively exerted, and the conductivity reliability of the connection structure after thermal cycling can be further improved.

[0183] The aforementioned conductive particles can be solder particles or metal particles. The aforementioned metal particles can be metal powder. The aforementioned conductive particles can have a substrate particle and a conductive portion disposed on the surface of the substrate particle. From the viewpoint of further improving the conductivity reliability of the connection structure after thermal cycling, the aforementioned conductive particles are preferably solder particles. From the viewpoint of further improving the conductivity reliability of the connection structure after thermal cycling, the aforementioned resin material preferably further contains solder particles. From the viewpoint of further improving the conductivity reliability of the connection structure after thermal cycling, the aforementioned resin material is preferably a solder paste containing solder particles. The aforementioned solder paste contains the aforementioned components of the aforementioned resin material.

[0184] The aforementioned solder particles have a central portion and an outer surface both formed of solder. These solder particles are particles whose central portion and outer surface are both composed of solder.

[0185] The solder is preferably a metal with a melting point below 450°C (low-melting-point metal). The solder particles are preferably metal particles with a melting point below 450°C (low-melting-point metal particles). These low-melting-point metal particles are particles containing a low-melting-point metal. The low-melting-point metal refers to a metal with a melting point below 450°C. The melting point of the low-melting-point metal is preferably below 300°C, more preferably below 220°C, and even more preferably below 190°C.

[0186] The melting point of the aforementioned solder particles is preferably 100°C or higher, more preferably 105°C or higher, more preferably 250°C or lower, and more preferably 245°C or lower. If the melting point of the aforementioned solder particles is above the lower limit and below the upper limit, the cohesiveness of the solder during conductive connection can be further improved more effectively. If the melting point of the aforementioned solder particles is above the lower limit and below the upper limit, when using a resin material (conductive material) to electrically connect the electrodes, the conductivity reliability can be further improved more effectively, and the insulation reliability can be further improved more effectively. The range of the melting point of the aforementioned solder particles can be appropriately set by selecting the aforementioned lower limit and upper limit values.

[0187] The melting point of the aforementioned solder particles can be determined using differential scanning calorimetry (DSC). Examples of DSC devices include the SII Corporation's "EXSTAR DSC7020".

[0188] Furthermore, the aforementioned solder particles preferably contain tin. Of the 100% by weight of metal contained in the solder particles, the tin content is preferably 30% by weight or more, more preferably 40% by weight or more, further preferably 70% by weight or more, and particularly preferably 90% by weight or more. If the tin content in the solder particles is at or above the aforementioned lower limit, the connection reliability between the solder and the electrode can be further improved more effectively. Of the 100% by weight of metal contained in the solder particles, the tin content can be 100% by weight or less, or less than 100% by weight. The range of tin content of 100% by weight of metal contained in the solder particles can be appropriately set by selecting the aforementioned lower limit and the aforementioned upper limit.

[0189] It should be noted that the tin content mentioned above can be determined using a high-frequency inductively coupled plasma emission spectrometer (ICP-AES manufactured by Horiba Corporation) or a fluorescence X-ray analyzer (EDX-800HS manufactured by Shimadzu Corporation).

[0190] By using the aforementioned solder particles, the solder melts and bonds to the electrodes, creating electrical conductivity between them. For example, since the solder portion and the electrode easily form surface contact rather than point contact, the connection resistance is reduced. Furthermore, by using the aforementioned solder particles, the bonding strength between the solder portion and the electrode is increased, resulting in greater difficulty in solder portion peeling from the electrode, thus further effectively improving conductivity and connection reliability.

[0191] The low-melting-point metal constituting the solder particles is not particularly limited. This low-melting-point metal is preferably tin or an alloy containing tin. Examples of such alloys include tin-silver alloys, tin-copper alloys, tin-silver-copper alloys, tin-bismuth alloys, tin-zinc alloys, and tin-indium alloys. Due to its excellent wettability to the electrode, the aforementioned low-melting-point metal is preferably tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy. More preferably, the aforementioned low-melting-point metal is a tin-bismuth alloy or a tin-indium alloy.

[0192] The solder particles described above are preferably deposition materials with a liquidus temperature of 450°C or below, based on JIS Z3001: Welding Terminology. Examples of compositions of the solder particles include, for instance, metallic compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium, etc. The solder particles preferably do not contain lead, and more preferably contain tin and indium, or tin and bismuth.

[0193] To further and effectively improve the bonding strength between the solder and the electrode, the solder particles may contain metals such as nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum, and palladium. Furthermore, from the viewpoint of further improving the bonding strength between the solder and the electrode, the solder particles preferably contain nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further and effectively improving the bonding strength between the solder and the electrode, the content of these metals used to improve the bonding strength is preferably 0.0001% by weight or more, and preferably 1% by weight or less, out of 100% by weight of the metals contained in the solder particles.

[0194] The average particle size of the solder particles is preferably 0.01 μm or more, more preferably 0.03 μm or more. If the average particle size of the solder particles is at or above the lower limit, the solder can be more effectively disposed on the electrode. The average particle size of the solder particles can be 10 μm or less, 5 μm or less, or 3 μm or less. The range of the average particle size of the solder particles can be appropriately set by selecting the lower and upper limits mentioned above.

[0195] The average particle size of the aforementioned solder particles is the number-average particle size. The average particle size of the aforementioned solder particles can be determined, for example, by observing any 50 solder particles using an electron microscope or an optical microscope and calculating the average particle size of each solder particle, or by performing laser diffraction particle size distribution measurement. When observing using an electron microscope or an optical microscope, the particle size of each solder particle is determined in terms of the equivalent circle diameter. When observing using an electron microscope or an optical microscope, the average particle size of any 50 solder particles, measured in terms of the equivalent circle diameter, is substantially equal to the average particle size measured in terms of the equivalent sphere diameter. In laser diffraction particle size distribution measurement, the particle size of each solder particle is determined in terms of the equivalent sphere diameter. The average particle size of the aforementioned solder particles is preferably calculated by laser diffraction particle size distribution measurement.

[0196] The coefficient of variation (CV) of the solder particle size is preferably 40% or less, more preferably 30% or less. If the coefficient of variation of the solder particle size is below the upper limit, the solder can be more effectively disposed on the electrode. The coefficient of variation (CV) of the solder particle size can be 0% or more, 1% or more, 5% or more, or 10% or more. However, the CV of the solder particle size can also be less than 5%. The range of the coefficient of variation of the solder particle size can be appropriately set by selecting the lower limit and the upper limit.

[0197] The coefficient of variation (CV) mentioned above can be determined as follows.

[0198] CV value (%) = (ρ / Dn) × 100

[0199] ρ: Standard deviation of solder particle size

[0200] Dn: Average particle size of solder particles

[0201] The shape of the solder particles is not particularly limited. The shape of the solder particles can be spherical or flat, or any other shape other than a sphere.

[0202] In 100% by weight of the aforementioned resin material (solder paste), the content of the aforementioned solder particles is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 10% by weight or more, particularly preferably 20% by weight or more, most preferably 30% by weight or more, preferably 80% by weight or less, more preferably 60% by weight or less, and further preferably 50% by weight or less. If the content of the aforementioned solder particles is above or below the aforementioned lower limit and below the aforementioned upper limit, the solder can be more effectively disposed on the electrodes, and it is easier to dispose of a larger amount of solder between the electrodes, thereby further improving the conductivity reliability of the connection structure after thermal cycling. From the viewpoint of further improving conductivity reliability, a higher content of the aforementioned solder particles is preferred.

[0203] The adhesive resin described above is not particularly limited. Known insulating resins can be used as the adhesive resin. The adhesive resin preferably contains a thermoplastic component (thermoplastic compound) or a curing component, more preferably a curing component. Examples of the curing component include photocurable components and thermocurable components. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermocurable component preferably contains a thermocurable compound and a thermosetting agent. Examples of the adhesive resin include, for example, vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one type of adhesive resin can be used, or two or more types can be used in combination.

[0204] Examples of vinyl resins include vinyl acetate resins, acrylic resins, and styrene resins. Examples of thermoplastic resins include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of curable resins include epoxy resins, urethane resins, polyimide resins, and unsaturated polyester resins. It should be noted that the curable resins can be room-temperature curing resins, thermosetting resins, light-curing resins, or moisture-curing resins. The curable resins can be used in combination with a curing agent. Examples of thermoplastic block copolymers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrides of styrene-butadiene-styrene block copolymers, and hydrides of styrene-isoprene-styrene block copolymers. Examples of elastomers include styrene-butadiene copolymer rubbers and acrylonitrile-styrene block copolymer rubbers.

[0205] In addition to the resin particles or metal-coated particles and the adhesive resin, the resin material may also contain various additives such as fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants.

[0206] As a method for dispersing the resin particles or the metal-coated particles in the adhesive resin, conventionally known dispersion methods can be used. Examples of methods for dispersing the resin particles or the metal-coated particles in the adhesive resin include: Adding the resin particles or the metal-coated particles to the adhesive resin and then mixing and dispersing them using a planetary mixer or the like; uniformly dispersing the resin particles or the metal-coated particles in water or an organic solvent using a homogenizer, then adding them to the adhesive resin and mixing and dispersing them using a planetary mixer or the like; diluting the adhesive resin with water or an organic solvent, then adding the resin particles or the metal-coated particles and mixing and dispersing them using a planetary mixer or the like.

[0207] The viscosity (η25) of the aforementioned resin material at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, more preferably 400 Pa·s or less, and more preferably 300 Pa·s or less. If the viscosity of the aforementioned resin material at 25°C is above the lower limit and below the upper limit, the reliability of the connection between electrodes can be further improved more effectively. The aforementioned viscosity (η25) can be appropriately adjusted according to the type and amount of the compounding components.

[0208] The aforementioned viscosity (η25) can be measured, for example, using an E-type viscometer at 25°C and 10 rpm. Examples of such an E-type viscometer include the "VISCOMETER TV-22" manufactured by Toki Sangyo Co., Ltd.

[0209] In the 100% by weight of the aforementioned resin material, the content of the adhesive resin is preferably 10% by weight or more, more preferably 30% by weight or more, further preferably 50% by weight or more, particularly preferably 70% by weight or more, preferably 99.99% by weight or less, even more preferably 99.9% by weight or less, even more preferably 99% by weight or less, even more preferably 98% by weight or less, even more preferably 90% by weight or less, even more preferably 80% by weight or less, particularly preferably 70% by weight or less, and most preferably 65% ​​by weight or less. If the content of the adhesive resin is above or below the aforementioned lower limit and below the aforementioned upper limit, the effects of the present invention can be further effectively achieved, and the conductivity reliability of the connection structure after thermal cycling can be further improved. Furthermore, if the content of the adhesive resin is above or below the aforementioned lower limit and below the aforementioned upper limit, conductive particles or metal-coated particles are effectively disposed between the electrodes, further increasing the connection reliability of the connection components connected by the resin material.

[0210] (Connection structure)

[0211] By using the aforementioned resin particles to connect the connecting components, a connecting structure can be obtained.

[0212] The connecting structure using the aforementioned resin particles includes a first connecting member, a second connecting member, and a connecting portion connecting the first connecting member and the second connecting member. In the connecting structure, the connecting portion comprises either the resin particles or the metal-coated particles. Preferably, the connecting portion is formed of the resin particles or the metal-coated particles, or of a composition comprising the resin particles.

[0213] Alternatively, a connection structure can be obtained by using a conductive material containing the aforementioned resin particles or metal-coated particles, adhesive resin, and conductive particles to connect the connecting components.

[0214] In the above-described connection structure, due to the aforementioned configuration, the gap controllability of the connection structure when exposed to high-temperature environments can be improved, and the conductivity reliability after thermal cycling can be improved.

[0215] The connection structure using the aforementioned resin particles or metal-coated particles includes a first connection member having a first electrode on its surface, a second connection member having a second electrode on its surface, and a connection portion connecting the first connection member and the second connection member. In the connection structure, the connection portion contains the aforementioned resin particles. Preferably, the connection portion is formed of a resin material (conductive material) containing the aforementioned resin particles or metal-coated particles, conductive particles, and an adhesive resin. The conductive particles are preferably solder particles. The resin material is preferably solder paste containing solder particles. When the connection portion is formed of a resin material (conductive material) containing the aforementioned resin particles or metal-coated particles, conductive particles, and an adhesive resin, the first electrode and the second electrode are preferably electrically connected via the conductive particles in the connection structure. When the connection portion is formed of a resin material (solder paste) containing the resin particles or the metal-coated particles, solder particles and adhesive resin, in the connection structure, it is more preferable that the first electrode and the second electrode are electrically connected through the solder portion.

[0216] From the viewpoint of further improving the conductivity reliability after thermal cycling and improving the dispersion of the components in the conductive material, in the above-described connection structure, it is more preferable that the connection portion is formed of a resin material (conductive material) comprising the aforementioned metal-coated particles, conductive particles, and adhesive resin. From the viewpoint of further improving the conductivity reliability after thermal cycling and improving the dispersion of the components in the conductive material, in the above-described connection structure, it is even more preferable that the connection portion is formed of a resin material (solder paste) comprising the aforementioned metal-coated particles, solder particles, and adhesive resin.

[0217] Figure 3 This is a cross-sectional view showing an example of a connecting structure obtained using the resin particles of the first embodiment of the present invention.

[0218] Figure 3 The connecting structure 41 shown includes a first connecting member 42, a second connecting member 43, and a connecting portion 44 connecting the first connecting member 42 and the second connecting member 43. The connecting portion 44 is formed of a resin material (solder paste) containing resin particles 1, solder particles, and adhesive resin. The resin particles 1 are used as spacers. The spacing between the first connecting member 42 and the second connecting member 43 is controlled by the resin particles 1.

[0219] Figure 4 This is a cross-sectional view showing an example of a connecting structure obtained using metal-coated particles, wherein the metal-coated particles are resin particles of the first embodiment of the present invention.

[0220] Figure 4 The connecting structure 51 shown includes a first connecting member 42, a second connecting member 43, and a connecting portion 44 connecting the first connecting member 42 and the second connecting member 43. The connecting portion 44 is formed of a resin material (solder paste) containing metal-coated particles 11, solder particles, and adhesive resin. The metal-coated particles 11 are used as spacers. The spacing between the first connecting member 42 and the second connecting member 43 is controlled by the metal-coated particles 11.

[0221] In the connecting structures 41 and 51, the connecting portion 44 has a solder portion 3 formed by the aggregation and bonding of multiple solder particles, and a resin portion 4 formed of an adhesive resin. When the adhesive resin contains a curable component, the resin portion is preferably a cured portion of the adhesive resin.

[0222] The first connecting member 42 has a plurality of first electrodes 42a on its surface (upper surface). The second connecting member 43 has a plurality of second electrodes 43a on its surface (lower surface). The first electrodes 42a and the second electrodes 43a are electrically connected by the solder portion 3. Therefore, the first connecting member 42 and the second connecting member 43 are electrically connected by the solder portion 3. It should be noted that in the connecting portion 44, there is no solder in the region (resin portion 4) different from the solder portion 3 that is concentrated between the first electrodes 42a and the second electrodes 43a. There is no solder separated from the solder portion 3 in the region different from the solder portion 3 (resin portion 4). It should be noted that, if it is a small amount, solder may also be present in the region (resin portion 4) different from the solder portion 3 that is concentrated between the first electrodes 42a and the second electrodes 43a.

[0223] like Figure 3 , 4 As shown, in the connecting structures 41 and 51, multiple solder particles aggregate between the first electrode 42a and the second electrode 43a. After the multiple solder particles melt, the molten solder particles wet and spread on the surface of the electrodes and solidify to form the solder portion 3. Therefore, the connection area between the solder portion 3 and the first electrode 42a, and between the solder portion 3 and the second electrode 43a, becomes larger. That is, by using solder particles, compared to the case where the outer surface of the conductive part is made of conductive particles such as nickel, gold, or copper, the contact area between the solder portion 3 and the first electrode 42a, and between the solder portion 3 and the second electrode 43a, becomes larger. Therefore, the conductivity reliability and connection reliability of the connecting structures 41 and 51 after thermal cycling are higher.

[0224] The manufacturing method of the aforementioned connecting structure is not particularly limited. As an example of a manufacturing method for the connecting structure, a method can be described that, after obtaining a laminate by disposing the aforementioned resin material (conductive material) between a first connecting member and a second connecting member, the laminate is then heated and pressurized. The pressure applied during pressurization is preferably 40 MPa or more, more preferably 60 MPa or more, preferably 90 MPa or less, more preferably 70 MPa or less. It should be noted that if the conductive material is solder paste containing solder particles, the connecting structure can be manufactured without pressurizing the laminate. The heating temperature is preferably 80°C or more, more preferably 100°C or more, preferably 250°C or less, more preferably 190°C or less.

[0225] The first and second connecting components described above are not particularly limited. Examples of the first and second connecting components include: electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, and diodes; and electronic components such as circuit boards such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid-flexible substrates, glass epoxy boards, and glass substrates. The first and second connecting components are preferably electronic components.

[0226] The resin material described above is preferably a conductive material used for connecting electronic components. The resin material is a paste-like conductive material, and is preferably applied to the component to be connected in a paste-like state.

[0227] The aforementioned resin particles, resin materials, and circuit connection materials are also suitable for use in touch panels. Therefore, the aforementioned connection component is preferably a flexible substrate, or a connection component with electrodes disposed on the surface of the resin film. The aforementioned connection component is preferably a flexible substrate, and more preferably a connection component with electrodes disposed on the surface of the resin film. When the aforementioned flexible substrate is a flexible printed circuit board or the like, the flexible substrate typically has electrodes on its surface.

[0228] Examples of electrodes disposed on the aforementioned connecting member 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 connecting member is a flexible printed circuit board, the electrodes are preferably gold, nickel, tin, silver, or copper electrodes. When the connecting member is a glass substrate, the electrodes are preferably aluminum, copper, molybdenum, or tungsten electrodes. It should be noted that when the electrode is an aluminum electrode, it can be an electrode formed solely of aluminum, or it can be an electrode with an aluminum layer stacked 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 trivalent metal elements include Sn, Al, and Ga.

[0229] Furthermore, the aforementioned resin particles are suitable for use as spacers for liquid crystal display elements. When the resin particles are used as spacers for liquid crystal display elements, the gap can be effectively controlled, preventing substrate damage. The first connecting member can be a member for a first liquid crystal display element. The second connecting member can be a member for a second liquid crystal display element. The connecting portion can be a sealing portion that seals the outer peripheries of the first liquid crystal display element member and the second liquid crystal display element member when they are facing each other.

[0230] The aforementioned resin particles can also be used as peripheral sealants for liquid crystal display elements. The liquid crystal display element includes a first liquid crystal display element component and a second liquid crystal display element component. The liquid crystal display element further includes: a sealing portion that seals the outer peripheries of the first liquid crystal display element component and the second liquid crystal display element component when they are facing each other; and liquid crystal disposed inside the sealing portion between the first liquid crystal display element component and the second liquid crystal display element component. In this liquid crystal display element, a liquid crystal droplet process is employed, and the sealing portion is formed by thermally curing a sealant used in the liquid crystal droplet process.

[0231] The present invention will now be specifically described by way of examples and comparative examples. The present invention is not limited to the examples described below.

[0232] The following materials have been prepared.

[0233] (polymeric components)

[0234] Divinylbenzene (manufactured by NS Styrene Monomer, "DVB960")

[0235] Styrene (styrene monomer manufactured by NS Styrene Monomer)

[0236] Methyl methacrylate (manufactured by Mitsubishi Chemical Corporation, "ACRYESTER M", 1 (meth)acryloyl group)

[0237] Ethylene glycol dimethacrylate (manufactured by Mitsubishi Chemical Corporation, "ACRYESTER ED", 2 (meth)acryloyl groups)

[0238] Trimethylolpropane trimethacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., with 3 (meth)acryloyl groups)

[0239] Pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., "A-TMMT", 4 (meth)acryloyl groups)

[0240] Dipentaerythritol polyacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., "A-DPH", with 5-6 (meth)acryloyl groups)

[0241] (Other components (solvents))

[0242] Toluene (manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd.)

[0243] (Polymerization initiator)

[0244] Benzoyl peroxide (manufactured by Tokyo Chemical Industry Co., Ltd., "BPO")

[0245] (Example 1)

[0246] (1) Preparation of resin particles

[0247] To 80 parts by weight of divinylbenzene (80% by weight of the polymerizable component out of 100% by weight), 20 parts by weight of pentaerythritol tetraacrylate (20% by weight of the polymerizable component out of 100% by weight) were added and stirred to obtain a monomer liquid. Next, 1 part by weight of a polymerization initiator (benzoyl peroxide) was added to the obtained monomer liquid and stirred until homogeneous to obtain a monomer mixture. 200 parts by weight of a 1.0% by weight aqueous solution of polyvinyl alcohol with a molecular weight of approximately 2000 dissolved in pure water were added to a reactor. The obtained monomer mixture was added to the reactor, and stirring was carried out until the monomer droplets reached the given particle size. Then, the monomer droplets were polymerized at 90°C for 9 hours to obtain particles. The obtained particles were washed three times each with hot water and acetone, and then fractionated to recover the resin particles.

[0248] (2) Fabrication of metal-coated particles

[0249] Ten parts by weight of the resin particles were dispersed in 100 parts by weight of an alkaline solution containing 5% palladium catalyst using an ultrasonic disperser, and the resin particles were collected by filtering the solution. Next, the resin particles were added to 100 parts by weight of a 1% dimethylamine borane solution to activate the surface of the resin particles. After thoroughly washing the activated resin particles with water, they were added to 500 parts by weight of distilled water and dispersed to obtain dispersion A.

[0250] In addition, as a nickel plating solution, a nickel plating solution (1) containing 0.14 mol / L nickel sulfate, 0.46 mol / L dimethylamine borane and 0.2 mol / L sodium citrate was prepared (pH 8.5).

[0251] While stirring the above dispersion A containing 10 parts by weight of resin particles at 70°C, nickel plating solution (1) was added dropwise at a rate of 30 mL / min for 10 minutes. Then, it was added dropwise at a rate of 10 mL / min for 40 minutes, and then at a rate of 4 mL / min for 80 minutes, thereby performing electroless nickel-boron alloy plating while controlling the boron content introduced into the coating. The particles were then removed by filtering the obtained dispersion, washed with water, and dried to obtain metal-coated particles with a metal coating layer (nickel layer) disposed on the surface of the resin particles.

[0252] (3) Preparation of resin materials

[0253] The following materials were mixed to obtain a mixture: 20 parts by weight of resin particles; 21 parts by weight of solder particles (Senju Metal Industries, Ltd., "Sn-Bi type solder alloy"); 25 parts by weight of bisphenol A type phenoxy resin; 4 parts by weight of fluorene type epoxy resin; 30 parts by weight of phenolic varnish type epoxy resin; SI-60L (Sanshin Chemical Industry Co., Ltd.). The obtained mixture was degassed and stirred for 3 minutes to obtain resin material (conductive paste, solder paste) A containing resin particles. Similarly, resin material B containing metal-coated particles was obtained, except that the resin particles were replaced with metal-coated particles.

[0254] (4) Fabrication of connecting structures

[0255] An LGA substrate with pads measuring 0.5mm × 0.5mm and a semiconductor chip were prepared. Resin materials (conductive paste, solder paste) A and B were screen-printed onto the LGA substrate to form solder paste layers. Next, the semiconductor chip was stacked on the solder paste layers with its electrodes facing each other. Then, reflow soldering was performed at 160°C to cure the solder paste layers, resulting in connection structures A and B. It should be noted that no pressure was applied during the reflow soldering process.

[0256] (Examples 2-12, 14 and Comparative Examples 2-4)

[0257] Except for the types and contents (by weight %) of polymerizable components, the average particle size and CV value of resin particles, and the type and thickness of the metal coating layer, as shown in Tables 1-4, resin particles, metal-coated particles, resin materials A and B, and connecting structures A and B were prepared in the same manner as in Example 1. It should be noted that the average particle size and CV value of the resin particles were adjusted by grading.

[0258] (Example 13)

[0259] (1) Preparation of resin particles

[0260] Except for the changes in the types and contents (by weight %) of polymeric components as shown in Table 3, resin particles were prepared in the same manner as in Example 1.

[0261] (2) Fabrication of metal-coated particles

[0262] Formation of the first metal cladding layer:

[0263] Particle A was obtained with a first metal coating layer (nickel layer, 100 nm thick) disposed on the surface of the resin particles.

[0264] Formation of the second metal cladding layer:

[0265] Ten parts by weight of the obtained particles A were dispersed in 500 parts by weight of ion-exchanged water using an ultrasonic treatment machine to obtain suspension B. A tin plating solution (1) containing 15 g / L tin sulfate, 70 g / L ethylenediaminetetraacetic acid, 30 g / L sodium gluconate, and 1.5 g / L phosphonic acid was prepared (adjusted to pH 8.5 with sodium hydroxide). In addition, a reducing solution A containing 5 g / L sodium borohydride was prepared (adjusted to pH 10.0 with sodium hydroxide).

[0266] While stirring the obtained suspension B at 55°C, the aforementioned tin plating solution (1) was slowly added to the suspension B, and then chemical tin plating was performed by reducing it using reducing solution A, forming a second metal coating layer. Metal-coated particles with a second metal coating layer (tin layer, 100 nm thick) disposed on the surface of the aforementioned first metal coating layer were obtained. In addition to using the obtained metal-coated particles, resin materials A and B and connecting structures A and B were fabricated in the same manner as in Example 1.

[0267] (Comparative Example 1)

[0268] 44.95 parts by weight of pentaerythritol tetraacrylate (50% by weight of 100% by weight of polymerizable component) were added to 44.95 parts by weight of divinylbenzene (50% by weight of 100% by weight of polymerizable component) and stirred to obtain a monomer liquid. Next, 10.1 parts by weight of solvent (toluene) were added to the obtained monomer liquid and stirred until homogeneous to obtain a monomer mixture. 200 parts by weight of a 1.0% by weight aqueous solution of polyvinyl alcohol with a molecular weight of approximately 2000 dissolved in pure water were added to a reactor. The obtained monomer mixture was added to it, and stirring was carried out until the monomer droplets reached a given particle size. Then, the monomer droplets were polymerized by heating at 90°C for 9 hours to obtain porous resin particles. In addition to using the obtained resin particles, metal-coated particles, resin materials A and B, and connecting structures A and B were prepared in the same manner as in Example 1.

[0269] (evaluate)

[0270] (1) Viscosity of the mixture of polymeric components

[0271] The viscosity of the mixture of polymerizable components (before polymerization) was measured using an E-type viscometer (VISCOMETER TV-22 manufactured by Toki Sangyo Co., Ltd.) at 25°C and 5 rpm.

[0272] (2) 20% K value of resin particles at 25℃ and 200℃

[0273] The 20% K values ​​of the obtained resin particles at 25°C and 200°C were determined using a micro compression tester (Elionix ENT-5) by the method described above. Furthermore, the ratio (20% K value at 25°C / 20% K value at 200°C) was calculated.

[0274] (3) Gas release amount when resin particles are heated at 250°C for 10 minutes

[0275] The amount of gas released when the resin particles were heated at 250°C for 10 minutes was determined using the method described above.

[0276] (4) Gap control (resin particles)

[0277] For the connecting structure A obtained using resin particles, it was heated to 250°C in an oven and left at that temperature for 1 hour. The minimum and maximum thicknesses of the connecting portion (cured conductive paste layer) were measured using a scanning electron microscope (SEM). Gap control (resin particles) was determined according to the following criteria.

[0278] [Criteria for determining gap control (resin particles)]

[0279] ○○○: The maximum thickness is less than 1.1 times the minimum thickness.

[0280] ○○: The maximum thickness is more than 1.1 times but less than 1.3 times the minimum thickness.

[0281] ○: The maximum thickness is more than 1.3 times but less than 1.5 times the minimum thickness.

[0282] ×: The maximum thickness is more than 1.5 times the minimum thickness.

[0283] (5) Gap control (metal-coated particles)

[0284] For the connecting structure B obtained using metal-coated particles, it was heated to 250°C in an oven and left at that temperature for 1 hour. The minimum and maximum thicknesses of the connecting portion (the cured conductive paste layer) were measured using a scanning electron microscope (SEM). Gap control (metal-coated particles) was determined according to the following criteria.

[0285] [Criteria for determining gap control (metal-coated particles)]

[0286] ○○○: The maximum thickness is less than 1.1 times the minimum thickness.

[0287] ○○: The maximum thickness is more than 1.1 times but less than 1.3 times the minimum thickness.

[0288] ○: The maximum thickness is more than 1.3 times but less than 1.5 times the minimum thickness.

[0289] ×: The maximum thickness is more than 1.5 times the minimum thickness.

[0290] (6) Conductivity reliability after thermal cycling (resin particles)

[0291] For the connection structure A obtained using resin particles, a thermal cycling test was conducted for 1000 cycles, consisting of heating from -20°C to 100°C and then cooling back to -20°C as one cycle. After the thermal cycling, the connection resistance A at each connection point between the upper and lower electrodes was measured using the four-terminal method. It should be noted that, based on the relationship voltage = current × resistance, the connection resistance can be determined by measuring the voltage flowing through a constant current. The conductivity reliability (resin particles) after the thermal cycling was determined according to the following criteria.

[0292] [Criteria for determining conductivity reliability (resin particles) after thermal cycling]

[0293] ○○○: Connection resistor A is less than 5mΩ

[0294] ○○: Connection resistance A exceeds 5mΩ but is less than 7mΩ

[0295] ○: Connection resistance A exceeds 7mΩ but is less than 10mΩ

[0296] ×: Connection resistance A exceeds 10mΩ, or a poor connection has occurred.

[0297] (7) Conductivity reliability after thermal cycling (metal-coated particles)

[0298] For the connection structure B obtained using metal-coated particles, a thermal cycling test was conducted for 1000 cycles, consisting of heating from -20°C to 100°C and then cooling back to -20°C as one cycle. After the thermal cycling, the connection resistance B at each connection point between the upper and lower electrodes was measured using the four-terminal method. It should be noted that, based on the relationship voltage = current × resistance, the connection resistance can be determined by measuring the voltage flowing through a constant current. The conductivity reliability (metal-coated particles) after the thermal cycling was determined according to the following criteria.

[0299] [Criteria for Determining Conductivity Reliability (Metal-Coated Particles) After Thermal Cycling]

[0300] ○○○: Connection resistor B is 5mΩ or less

[0301] ○○: Connection resistance B exceeds 5mΩ but is less than 7mΩ

[0302] ○: Connection resistance B exceeds 7mΩ but is less than 10mΩ

[0303] ×: Connection resistance B exceeds 10mΩ, or a poor connection has occurred.

[0304] The composition and results of the resin particles and metal-coated particles are shown in Tables 1-4 below.

[0305]

[0306]

[0307]

[0308]

[0309] In addition, Examples 6 (particle size 1 μm), 7 (particle size 5 μm), 8 (particle size 10 μm), 3 (particle size 30 μm), and 9 (particle size 50 μm), which only changed the particle size of the resin particles, are shown in Table 5 below.

[0310]

[0311] According to the results shown in Table 5 above, in addition to 1) using specific polymerizable components and 2) the compressive modulus of the resin particles being within a specific range, if 3A) the particle size of the resin particles is 5 μm or more, the gap control of the connecting structure when exposed to a high-temperature environment can be further improved compared to the case where the particle size of the resin particles is less than 5 μm. Furthermore, it is known that, in addition to 1) using specific polymerizable components and 2) the compressive modulus of the resin particles being within a specific range, if 3B) the particle size of the resin particles is 20 μm or more, the gap control of the connecting structure when exposed to a high-temperature environment can be further improved compared to the case where the particle size of the resin particles is less than 20 μm.

[0312] It should be noted that the gap control (resin particles) results for Example 7 (particle size 5 μm) and Example 8 (particle size 10 μm) are both "○○", but in terms of the maximum thickness / minimum thickness value in the evaluation of gap control (resin particles), Example 8 is smaller than Example 7, and the gap control (resin particles) of Example 8 is superior to that of Example 7. Furthermore, the gap control (metal-coated particles) results for Example 7 (particle size 5 μm) and Example 8 (particle size 10 μm) are both "○○", but in terms of the maximum thickness / minimum thickness value in the evaluation of gap control (metal-coated particles), Example 8 is smaller than that of Example 7, and the gap control (metal-coated particles) of Example 8 is superior to that of Example 7.

[0313] Furthermore, according to the results shown in Table 5 above, except for 1) using specific polymerizable components and 2) the compressive modulus of the resin particles being within a specific range, if 3C) the particle size of the resin particles is 10 μm or more, then compared with the case where the particle size of the resin particles is less than 10 μm, the conductivity reliability of the connection structure after thermal cycling can be significantly improved.

Claims

1. A resin particle, which is a polymeric resin particle containing polymeric components. The polymerizable component comprises divinylbenzene and a (meth)acrylate compound having four or more (meth)acryloyl groups. The compressive modulus of the resin particles when compressed by 20% at 200°C is 1000 N / mm². 2 above.

2. The resin particles according to claim 1, wherein, Of the 100% by weight of the polymerizable component, the total content of the divinylbenzene and the (meth)acrylate compound having four or more (meth)acryloyl groups is 80% by weight or more.

3. The resin particles according to claim 1 or 2, wherein, The content of the divinylbenzene in the polymerizable component is, by weight, 0.40 or more and 1.70 or less relative to the content of the (meth)acrylate compound having four or more (meth)acryloyl groups in the polymerizable component.

4. The resin particles according to any one of claims 1 to 3, wherein, The amount of gas released when the resin particles were heated at 250°C for 10 minutes was less than 1000 ppm.

5. The resin particles according to any one of claims 1 to 4, wherein, The resin particles have a particle size of 1 μm or more and 100 μm or less.

6. The resin particles according to any one of claims 1 to 5, wherein, The resin particles are used to obtain metal-coated particles having the metal coating by forming a metal coating layer on the surface, or the resin particles have a particle size of 5 μm or more and 100 μm or less.

7. The resin particles according to claim 6, wherein, The resin particles are used to obtain metal-coated particles having the metal coating layer by forming a metal coating layer on the surface, or the resin particles have a particle size of 20 μm or more and 100 μm or less.

8. The resin particles according to any one of claims 1 to 5, wherein, The resin particles are used to obtain metal-coated particles having the metal coating layer by forming a metal coating layer on the surface.

9. The resin particles according to claim 5, wherein, The resin particles have a particle size of 5 μm or more and 100 μm or less.

10. The resin particles according to claim 9, wherein, The resin particles have a particle size of 20 μm or more and 100 μm or less.

11. A metal-coated particle, comprising: The resin particles according to any one of claims 1 to 10, and A metal coating layer disposed on the surface of the resin particles.

12. The metal-coated particles according to claim 11, wherein, The thickness of the metal cladding layer is 0.2 μm or more.

13. A resin material comprising an adhesive resin and resin particles according to any one of claims 1 to 10, or a resin material comprising an adhesive resin and metal-coated particles having said resin particles and a metal coating layer disposed on the surface of said resin particles. The resin particles or the metal-coated particles are dispersed in the adhesive resin.

14. The resin material according to claim 13, wherein, The resin material is solder paste containing solder particles.

15. Use of the resin particle according to any one of claims 1 to 10, or the resin particle and the metal-coated particle disposed on the surface of the resin particle, in a solder paste containing solder particles and a binder resin.

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