WO2024117182A1 - 導電ペースト、ｒｆｉｄインレイ及びｒｆｉｄインレイの製造方法 - Google Patents

導電ペースト、ｒｆｉｄインレイ及びｒｆｉｄインレイの製造方法 Download PDF

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WO2024117182A1
WO2024117182A1 PCT/JP2023/042742 JP2023042742W WO2024117182A1 WO 2024117182 A1 WO2024117182 A1 WO 2024117182A1 JP 2023042742 W JP2023042742 W JP 2023042742W WO 2024117182 A1 WO2024117182 A1 WO 2024117182A1
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Prior art keywords
conductive paste
conductive
meth
acrylate
less
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PCT/JP2023/042742
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English (en)
French (fr)
Japanese (ja)
Inventor
洋 小林
悠人 土橋
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Sekisui Chemical Co Ltd
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Sekisui Chemical Co Ltd
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Priority to JP2024519636A priority Critical patent/JP7808188B2/ja
Priority to CN202380059011.4A priority patent/CN119678227A/zh
Publication of WO2024117182A1 publication Critical patent/WO2024117182A1/ja
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
    • C09J9/02—Electrically-conducting adhesives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
    • H10W72/00—Interconnections or connectors in packages
    • H10W72/071—Connecting or disconnecting

Definitions

  • the present invention relates to a conductive paste containing a conductive filler.
  • the present invention also relates to an RFID inlay using the conductive paste and a method for manufacturing an RFID inlay.
  • UHF Ultra High Frequency
  • RFID inlays which allow contactless data transmission and reception, are widely used in contactless RFID tags and contactless RFID cards.
  • UHF Ultra High Frequency
  • RFID inlays have attracted attention due to their long communication distances, and UHF band RFID inlays are used for a variety of items and purposes, such as commuter passes, inventory management, distribution management, and history management.
  • a conductive paste containing a conductive filler and binder resin may be used to bond and connect a chip with electrodes on its surface to a substrate with wiring (antenna pattern) on its surface.
  • Patent Document 1 discloses an adhesive that can be used for electronic components.
  • the adhesive is an acrylic adhesive composition that contains a radical initiator with a 10-hour half-life temperature of 80°C or less, a vinylene-containing oligomer, and at least one diluent.
  • the adhesive can snap cure at low temperatures, and the pot life of the adhesive at room temperature is 24 hours or more.
  • Patent Document 2 discloses a conductive adhesive that contains a polymerizable acrylic compound, an organic peroxide, and solder particles, and in which the one-minute half-life temperature of the organic peroxide is lower than the solidus temperature of the solder particles.
  • liquid pools can occur and the amount of droplets dispensed can change.
  • conductive paste is sometimes placed not only in the adhesive area between the chip and the substrate, but also around the chip, and with a fillet formed, the conductive paste is hardened by heating and pressure before mounting. In this case, heating may be insufficient at the fillet (especially the end of the fillet), and the conductive paste may not harden sufficiently. As a result, there is an issue of reduced electrical conductivity reliability in the resulting electronic component.
  • the substrate may deform.
  • the wiring on the substrate's surface may deform, reducing the electrical conductivity reliability of the resulting electronic components.
  • the object of the present invention is to provide a conductive paste that can improve discharge stability, can improve electrical conductivity reliability even when mounted at a relatively low temperature, and can maintain high electrical conductivity reliability even when cooling and heating are repeated.
  • Another object of the present invention is to provide an RFID inlay using the conductive paste and a method for manufacturing an RFID inlay.
  • This specification discloses the following conductive paste, RFID inlay, and method for manufacturing an RFID inlay.
  • Item 1 A conductive paste containing a curable compound, a curing agent, and a plurality of conductive fillers, in which, when the conductive paste is heated from 25°C to 150°C at a heating rate of 10°C/min and differential scanning calorimetry is performed, the heat generation start temperature is 80°C or higher, the heat generation peak top temperature is 85°C or higher and 105°C or lower, and the heat generation end temperature is 110°C or lower.
  • Item 2 The conductive paste according to item 1, in which the absolute value of the difference between the heat generation start temperature and the heat generation end temperature in the differential scanning calorimetry is 13°C or less.
  • Item 3 The conductive paste according to item 1 or 2, in which the cure shrinkage rate when the conductive paste is heated at 130°C for 10 minutes and cured is 10% or less.
  • Item 4 The conductive paste according to any one of items 1 to 3, wherein the curable compound includes a (meth)acrylic compound.
  • Item 5 The conductive paste according to any one of items 1 to 4, wherein the curable compound contains a polymerizable monomer having one (meth)acryloyl group, and the content of the polymerizable monomer in 100% by weight of the curable compound is 50% by weight or less.
  • Item 6 A conductive paste according to any one of items 1 to 5, used to obtain an RFID inlay.
  • Item 7 An RFID inlay comprising a substrate having wiring on its surface, a chip having electrodes on its surface, and an adhesive portion bonding the substrate and the chip, the adhesive portion being made of the conductive paste described in any one of items 1 to 6, and the wiring and the electrodes being electrically connected by the conductive filler in the adhesive portion.
  • Item 8 A method for manufacturing an RFID inlay, comprising: a first arrangement step of arranging the conductive paste described in any one of items 1 to 6 on a surface of a substrate having wiring on its surface; a second arrangement step of arranging a chip having an electrode on its surface on the surface of the conductive paste opposite the substrate; and a bonding step of forming an adhesive part that bonds the substrate and the chip with the conductive paste by heating and pressurizing the conductive paste, and electrically connecting the wiring and the electrode with the conductive filler in the adhesive part.
  • Item 9 The method for manufacturing an RFID inlay according to Item 8, in which the substrate is long and the RFID inlay is manufactured by transporting the long substrate in the first placement process, the second placement process, and the bonding process using a roll-to-roll method.
  • the conductive paste according to the present invention is a conductive paste containing a curable compound, a curing agent, and a plurality of conductive fillers, and when the conductive paste is heated from 25°C to 150°C at a heating rate of 10°C/min and differential scanning calorimetry is performed, the heat generation start temperature is 80°C or higher, the heat generation peak top temperature is 85°C or higher and 105°C or lower, and the heat generation end temperature is 110°C or lower. Since the conductive paste according to the present invention has the above configuration, it is possible to increase the discharge stability, to increase the conductivity reliability even when mounted at a relatively low temperature, and to maintain high conductivity reliability even when cooling and heating are repeated.
  • FIG. 1 is a cross-sectional view showing a schematic diagram of an RFID inlay using a conductive paste according to a first embodiment of the present invention.
  • the conductive paste according to the present invention is a conductive paste containing a curable compound, a curing agent, and a plurality of conductive fillers.
  • the conductive paste according to the present invention is heated from 25° C. to 150° C. at a temperature increase rate of 10° C./min and subjected to differential scanning calorimetry, the conductive paste has a heat generation start temperature of 80° C. or higher, a heat generation peak top temperature of 85° C. or higher and 105° C. or lower, and a heat generation end temperature of 110° C. or lower.
  • the conductive paste according to the present invention has the above-mentioned configuration, and therefore can improve the discharge stability. In particular, the discharge stability by a jet dispenser can be improved. Furthermore, the conductive paste according to the present invention has the above-mentioned configuration, and therefore can be sufficiently cured at a relatively low temperature (for example, 160°C to 180°C). Furthermore, the conductive paste according to the present invention can improve the conductivity reliability even when mounted at a relatively low temperature. Furthermore, the conductive paste according to the present invention has the above-mentioned configuration, and therefore can maintain high conductivity reliability (improve the thermal cycle characteristics) even when the connection structure (electronic component) is repeatedly cooled and heated. In other words, the conductive paste according to the present invention can improve the conductivity reliability even when mounted at a relatively low temperature and when cooling and heating are repeatedly performed.
  • the conductive paste is heated from 25°C to 150°C at a heating rate of 10°C/min, and differential scanning calorimetry (DSC) is performed.
  • DSC differential scanning calorimetry
  • the conductive paste according to the present invention has a heat generation start temperature of 80°C or higher, a heat generation peak top temperature of 85°C to 105°C, and a heat generation end temperature of 110°C or lower.
  • the heat generation start temperature refers to the temperature at which the amount of heat generated starts to increase from the baseline.
  • the heat generation end temperature refers to the temperature at which, after reaching the heat generation peak top, the amount of heat generated has decreased to 1% of the amount of heat generated at the heat generation peak top.
  • the above differential scanning calorimetry can be performed in the following manner.
  • a differential scanning calorimetry device is prepared. 5 mg of the above conductive paste is placed in a dedicated aluminum pan (aluminum container) and the lid is closed using a dedicated tool.
  • the dedicated aluminum pan containing the conductive paste and an empty aluminum pan (reference) are placed in a heating unit and heated in a nitrogen atmosphere from 25°C to 150°C at a temperature increase rate of 10°C/min, and the reverse heat flow and non-reverse heat flow are observed.
  • the heat generation peak observed in the non-reverse heat flow is regarded as the heat generation peak of the conductive paste.
  • An example of the above differential scanning calorimetry device is the "TA7000" manufactured by Hitachi High-Tech Science Corporation.
  • the heat generation start temperature in the differential scanning calorimetry measurement is preferably 82°C or higher, and more preferably 85°C or higher. There is no particular upper limit to the heat generation start temperature.
  • the heat generation start temperature may be 105°C or lower, 103°C or lower, 100°C or lower, or 90°C or lower.
  • the heat generation peak top temperature in the above differential scanning calorimetry is preferably 88°C or higher, more preferably 90°C or higher, and is preferably 103°C or lower, more preferably 100°C or lower.
  • the heat generation end temperature in the differential scanning calorimetry measurement is preferably 108°C or less, and more preferably 105°C or less. There is no particular limit to the lower limit of the heat generation end temperature.
  • the heat generation end temperature may be 90°C or more, or may be 95°C or more.
  • the absolute value of the difference between the heat generation start temperature and the heat generation end temperature is preferably 1°C or more, more preferably 3°C or more, even more preferably 5°C or more, and is preferably 25°C or less, more preferably 20°C or less, even more preferably 15°C or less, and particularly preferably 13°C or less. If the absolute value of the difference between the heat generation start temperature and the heat generation end temperature is equal to or more than the above lower limit and equal to or less than the above upper limit, the storage stability of the conductive paste can be improved, and the conductivity reliability can be further improved even when mounted at a relatively low temperature.
  • examples of methods for adjusting the heat generation start temperature, heat generation peak top temperature, and heat generation end temperature to the above preferred ranges include the following methods.
  • the conductive paste according to the present invention is in a paste form at 25°C.
  • the conductive paste is used by discharging it at, for example, 20°C to 50°C. It is preferable that the conductive paste according to the present invention is used by discharging it using a jet dispenser.
  • the conductive paste has good adhesive properties.
  • the conductive paste is suitable for use as an adhesive.
  • the conductive paste is particularly suitable for use in bonding a substrate and a chip.
  • the conductive paste is preferably an anisotropic conductive paste.
  • the conductive paste is preferably used for electrically connecting electrodes.
  • the conductive paste is preferably used for obtaining a connection structure.
  • the conductive paste is preferably used for obtaining electronic components.
  • the conductive paste is particularly preferably used for obtaining an RFID inlay (use of the conductive paste for obtaining an RFID inlay).
  • the conductive paste is preferably used for bonding and connecting a chip having an electrode on its surface to a substrate having wiring (antenna pattern) on its surface (use of the conductive paste for bonding and connecting a chip having an electrode on its surface to a substrate having wiring (antenna pattern) on its surface).
  • the conductive paste is preferably used by being applied to a substrate having a surface tension of 30 mN/m or more and 50 mN/m or less (use of the conductive paste on a substrate having a surface tension of 30 mN/m or more and 50 mN/m or less).
  • the conductive paste is preferably used to bond a chip having a planar area of 0.50 mm2 or less (use of the conductive paste for bonding a chip having a planar area of 0.50 mm2 or less).
  • the conductive paste is preferably thermosetting.
  • the conductive paste is preferably a thermosetting conductive paste, and more preferably a thermosetting anisotropic conductive paste.
  • the curing shrinkage rate when the conductive paste is cured by heating at 130°C for 10 minutes is preferably 13% or less, more preferably 10% or less, even more preferably 9% or less, and particularly preferably 7% or less.
  • the curing shrinkage rate may be 0%, 0% or more, or 3% or more.
  • the cure shrinkage rate is measured, for example, as follows.
  • the conductive paste is applied onto a glass substrate, and the specific gravity of the conductive paste (before curing) is measured using an AccuPyc II 1340 manufactured by Micrometrics.
  • the conductive paste is then heated at 130°C for 10 minutes to form a cured product of the conductive paste.
  • the specific gravity of the resulting cured product of the conductive paste is measured using an AccuPyc II 1340 manufactured by Micrometrics.
  • the cure shrinkage rate is calculated using the following formula.
  • Cure shrinkage rate (specific gravity of cured conductive paste - specific gravity of conductive paste) x 100 / specific gravity of conductive paste
  • (meth)acrylate refers to acrylate and methacrylate.
  • (meth)acrylic refers to acrylic and methacrylic.
  • (meth)acryloyl refers to acryloyl and methacryloyl.
  • the curable compound includes a thermosetting compound and a photocurable compound.
  • the curable compound is preferably a thermosetting compound.
  • the thermosetting compound is a compound that can be cured by heating.
  • the thermosetting compound includes a (meth)acrylic compound, an oxetane compound, an epoxy compound, an episulfide compound, a phenol compound, an amino compound, an unsaturated polyester compound, a polyurethane compound, a silicone compound, and a polyimide compound.
  • the curable compound may be used alone or in combination of two or more kinds.
  • the curable compound preferably contains an epoxy compound or a (meth)acrylic compound, and more preferably contains a (meth)acrylic compound. From the viewpoint of improving adhesion, the curable compound more preferably contains a compound having a (meth)acryloyl group ((meth)acrylate).
  • the (meth)acrylic compound may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate.
  • the polyfunctional (meth)acrylate may be a difunctional (meth)acrylate, a trifunctional (meth)acrylate, or a tetrafunctional or higher (meth)acrylate.
  • the (meth)acrylic compound may have 100 or less (meth)acryloyl groups, 50 or less, or 10 or less. Only one type of the (meth)acrylic compound may be used, or two or more types may be used in combination.
  • the above monofunctional (meth)acrylates include 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, lauryl (meth)acrylate, isobutyl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, octyl/decyl (meth)acrylate, tridecyl (meth)acrylate, nonyl (meth)acrylate, caprolactone (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (3-ethyloxene
  • acrylates include methyl acrylate (meth)acrylate, methoxyethy
  • polyfunctional (meth)acrylates include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol (meth)acrylate, 1,9-nonanediol di(meth)acrylate, polyethylene glycol (200) di(meth)acrylate, tetraethylene glycol di(meth)acrylate, triethylene glycol (meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, dipropylene glycol di(meth)acrylate, alkoxylated hexanediol di(meth)acrylate, dodecanediol di(meth)acrylate, Examples of such acrylates include polyethylene glycol (600) di(meth)acrylate, 1,
  • the (meth)acrylic compound contains a polymerizable monomer having one (meth)acryloyl group (hereinafter, sometimes referred to as "polymerizable monomer (A)").
  • the curable compound contains a polymerizable monomer having one (meth)acryloyl group (polymerizable monomer (A)).
  • the (A) polymerizable monomer is a monofunctional (meth)acrylate.
  • the (A) polymerizable monomer is a polymerizable component that can be homopolymerized or copolymerized.
  • the (A) polymerizable monomer has an aromatic skeleton or an alicyclic skeleton.
  • the (A) polymerizable monomer may have an aromatic skeleton, an alicyclic skeleton, or both an aromatic skeleton and an alicyclic skeleton.
  • the (A) polymerizable monomer may include a polymerizable monomer having an aromatic skeleton and a polymerizable monomer having an alicyclic skeleton.
  • Examples of the (A) polymerizable monomer having an aromatic skeleton include 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, ethoxylated (4) nonylphenol (meth)acrylate, and alkoxylated phenol (meth)acrylate.
  • Examples of the polymerizable monomer (A) having an alicyclic skeleton include cyclohexyl (meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, isobornyl (meth)acrylate, 4-tert-butylcyclohexanol, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, acrylomorpholine, N-acryloyloxyethylhexahydrophthalimide, and 3,3,5-trimethylcyclohexyl (meth)acrylate.
  • the polymerizable monomer (A) is isobornyl (meth)acrylate.
  • the molecular weight of the (A) polymerizable monomer is preferably 50 or more, more preferably 100 or more, even more preferably 150 or more, and particularly preferably 200 or more, and is preferably 1000 or less, more preferably less than 1000, even more preferably 900 or less, particularly preferably 800 or less, and most preferably 700 or less.
  • the viscosity of the conductive paste can be adjusted to a suitable range, and the conductivity reliability can be further improved.
  • the molecular weight of the (A) polymerizable monomer means the molecular weight that can be calculated from the structural formula of the (A) polymerizable monomer when the structural formula of the (A) polymerizable monomer can be identified.
  • the molecular weight means the weight average molecular weight.
  • the weight average molecular weight indicates the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). Since the (A) polymerizable monomer has a relatively small molecular weight, the structural formula can generally be identified.
  • the weight average molecular weight can be measured using the following measuring device and under the following measuring conditions.
  • Measurement device "Waters GPC System (Waters 2690 + Waters 2414 (RI))" manufactured by Japan Waters Corporation Column: Shodex GPC LF-G x 1, Shodex GPC LF-804 x 2 Mobile phase: THF 1.0 mL/min Sample concentration: 5 mg/mL Detector: Refractive Index Detector (RID) Standard material: polystyrene (manufactured by TOSOH Corporation, weight average molecular weight: 620 to 590,000)
  • the (meth)acrylic compound may contain a (meth)acrylic compound other than the (A) polymerizable monomer.
  • the (meth)acrylic compound other than the (A) polymerizable monomer may be used alone or in combination of two or more.
  • the (meth)acrylic compound other than the (A) polymerizable monomer has two or more (meth)acryloyl groups. It is preferable that the (meth)acrylic compound other than the (A) polymerizable monomer is a polyfunctional (meth)acrylate.
  • the (meth)acrylic compound other than the (A) polymerizable monomer may have two (meth)acryloyl groups, two or more, three or more, four or more, or ten or less.
  • the (meth)acrylic compound other than the (A) polymerizable monomer contains urethane (meth)acrylate.
  • the molecular weight of the urethane (meth)acrylate is preferably 1000 or more, more preferably 1500 or more, even more preferably 2000 or more, even more preferably 3000 or more, and particularly preferably 5000 or more, and is preferably 30000 or less, more preferably 25000 or less, even more preferably 20000 or less, and particularly preferably 18000 or less.
  • the adhesiveness can be further improved and the conductivity reliability can be further improved.
  • the molecular weight of the urethane (meth)acrylate refers to the molecular weight that can be calculated from the structural formula of the urethane (meth)acrylate when the structural formula of the urethane (meth)acrylate can be identified.
  • the molecular weight refers to the weight average molecular weight.
  • the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).
  • the molecular weight of the urethane (meth)acrylate is preferably the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).
  • the weight average molecular weight can be measured using the following measuring device and under the following measuring conditions.
  • Measurement device "Waters GPC System (Waters 2690 + Waters 2414 (RI))" manufactured by Japan Waters Corporation Column: Shodex GPC LF-G x 1, Shodex GPC LF-804 x 2 Mobile phase: THF 1.0 mL/min Sample concentration: 5 mg/mL Detector: Refractive Index Detector (RID) Standard material: polystyrene (manufactured by TOSOH Corporation, weight average molecular weight: 620 to 590,000)
  • the content of the curable compound in the conductive paste (100% by weight) is preferably 15% by weight or more, more preferably 20% by weight or more, and preferably 60% by weight or less, more preferably 55% by weight or less, and even more preferably 50% by weight or less.
  • the content of the curable compound is equal to or more than the lower limit and equal to or less than the upper limit, the adhesiveness can be further improved and the electrical conductivity reliability can be further improved.
  • the content of the (A) polymerizable monomer is preferably 10% by weight or more, more preferably 15% by weight or more, and preferably 50% by weight or less, more preferably 45% by weight or less, even more preferably 40% by weight or less, and particularly preferably 35% by weight or less.
  • the content of the (A) polymerizable monomer is equal to or more than the lower limit and equal to or less than the upper limit, the electrical conductivity reliability can be further improved.
  • the content of the (A) polymerizable monomer indicates the total content of the polymerizable monomer having an aromatic skeleton and the polymerizable monomer having an alicyclic skeleton.
  • the content of the polymerizable monomer (A) is preferably 10% by weight or more, more preferably 15% by weight or more, and even more preferably 20% by weight or more, and is preferably 65% by weight or less, more preferably 60% by weight or less, and even more preferably 50% by weight or less.
  • the content of the polymerizable monomer (A) is equal to or more than the lower limit and equal to or less than the upper limit, the viscosity of the conductive paste can be adjusted to a suitable range, and the adhesiveness can be improved and the electrical reliability can be further improved.
  • the content of the polymerizable monomer indicates the total content of the polymerizable monomer having an aromatic skeleton and the polymerizable monomer having an alicyclic skeleton.
  • the content of the urethane (meth)acrylate in 100% by weight of the curable compound is preferably 15% by weight or more, more preferably 20% by weight or more, and preferably 80% by weight or less, more preferably 70% by weight or less.
  • the adhesiveness can be increased and the electrical conductivity reliability can be further improved.
  • the total content of the polymerizable monomer (A) and the urethane (meth)acrylate is preferably 20% by weight or more, more preferably 40% by weight or more, and preferably 90% by weight or less, more preferably 80% by weight or less.
  • the viscosity of the conductive paste can be adjusted to a suitable range, and the adhesiveness can be increased and the electrical conductivity reliability can be further improved.
  • the content of the (A) polymerizable monomer is preferably 15% by weight or more, more preferably 20% by weight or more, and preferably 55% by weight or less, more preferably 50% by weight or less, out of a total of 100% by weight of the (A) polymerizable monomer and the urethane (meth)acrylate.
  • the content of the (A) polymerizable monomer is equal to or more than the lower limit and equal to or less than the upper limit, the viscosity of the conductive paste can be adjusted to a suitable range, and the adhesiveness can be improved and the electrical reliability can be further improved.
  • the content of the (A) polymerizable monomer indicates the total content of the polymerizable monomer having an aromatic skeleton and the polymerizable monomer having an alicyclic skeleton.
  • the conductive paste includes a plurality of conductive fillers.
  • the conductive fillers are not particularly limited.
  • the conductive fillers may be conductive particles or carbon fibers.
  • "including a plurality of conductive fillers” means that the conductive paste includes two or more conductive fillers. Only one type of the conductive filler may be used, or two or more types may be used in combination.
  • the shape of the conductive filler is not particularly limited.
  • the shape of the conductive filler may be spherical, may be a shape other than spherical, or may be flat, etc.
  • the conductive filler is preferably a conductive particle.
  • the conductive particle may be a solder particle or a metal particle.
  • the metal particle may be a metal powder.
  • the conductive particle may include a base particle and a conductive portion disposed on the surface of the base particle. From the viewpoint of further increasing the reliability of conduction, the conductive particle preferably includes a base particle and a conductive portion disposed on the surface of the base particle.
  • the particle diameter of the conductive particles is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, even more preferably 2 ⁇ m or more, and is preferably 100 ⁇ m or less, more preferably 30 ⁇ m or less, even more preferably 10 ⁇ m or less.
  • the particle diameter of the conductive particles is equal to or more than the lower limit and equal to or less than the upper limit, the electrical conductivity reliability can be further improved.
  • the particle diameter of the conductive particles is preferably an average particle diameter, and more preferably a number average particle diameter.
  • the average particle diameter of the conductive particles can be determined, for example, by observing 50 random conductive particles with an electron microscope or optical microscope and calculating the average particle diameter of each conductive particle, or by performing laser diffraction particle size distribution measurement.
  • the particle diameter of the conductive particles is measured by observing 50 arbitrary conductive particles with an electron microscope or optical microscope, the measurement can be performed, for example, as follows.
  • the conductive particles are added to "Technovit 4000" manufactured by Kulzer so that the content of the conductive particles is 30% by weight, and dispersed to prepare an embedding resin body for conductive particle inspection.
  • a cross section of the conductive particle is cut out using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin body for conductive particle inspection.
  • the image magnification is set to 25,000 times, 50 conductive particles are randomly selected, and each conductive particle is observed.
  • the circle equivalent diameter of each conductive particle is measured, and the arithmetic average of the measured diameters is determined as the particle diameter of the conductive particle.
  • the coefficient of variation (CV value) of the particle diameter of the conductive particles is preferably 10% or less, more preferably 5% or less.
  • the coefficient of variation of the particle diameter of the conductive particles is equal to or less than the upper limit, the reliability of electrical conductivity can be further improved.
  • the coefficient of variation (CV value) of the particle diameter of the conductive particles may be 0% or more, or 1% or more.
  • CV value The above coefficient of variation (CV value) can be measured as follows.
  • CV value (%) ( ⁇ /Dn) ⁇ 100 ⁇ : Standard deviation of the particle diameter of the conductive particles Dn: Average particle diameter of the conductive particles
  • the conductive filler content in the conductive paste (100% by weight) is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and is preferably 80% by weight or less, more preferably 60% by weight or less, even more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less.
  • the electrical conductivity reliability can be further improved.
  • the content of the conductive filler relative to 100 parts by weight of the curable compound in the conductive paste is preferably 2 parts by weight or more, more preferably 3 parts by weight or more, even more preferably 5 parts by weight or more, and particularly preferably 7 parts by weight or more.
  • the content of the conductive filler relative to 100 parts by weight of the curable compound in the conductive paste is preferably 35 parts by weight or less, more preferably 30 parts by weight or less, even more preferably 25 parts by weight or less, and particularly preferably 20 parts by weight or less.
  • the conductive filler preferably contains a metal.
  • the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, ruthenium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, as well as alloys thereof.
  • Tin-doped indium oxide (ITO) may also be used as the metal. Only one of the above metals may be used, or two or more of them may be used in combination.
  • the conductive filler preferably contains a tin-containing alloy, nickel, palladium, ruthenium, silver, copper or gold, and more preferably contains nickel or palladium. From the viewpoint of increasing the corrosion resistance of the conductive filler and maintaining high electrical conductivity reliability, the conductive filler preferably contains nickel or gold, and more preferably contains nickel. From the viewpoint of increasing the corrosion resistance of the conductive filler and maintaining high electrical conductivity reliability, it is particularly preferable that the conductive filler contains nickel on the outer surface.
  • the conductive particles are metal particles
  • examples of the metal particles include silver, copper, nickel, silicon, gold, titanium, and alloys such as solder. From the viewpoint of more effectively increasing the reliability of electrical conduction, it is preferable that the material of the metal particles contains nickel or a nickel alloy, and it is more preferable that the material of the metal particles is nickel or a nickel alloy. From the viewpoint of more effectively increasing the reliability of electrical conduction, it is preferable that the outer surface portion of the metal particles contains nickel or a nickel alloy.
  • the conductive particle which includes a base particle and a conductive portion disposed on the surface of the base particle.
  • the base particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles.
  • the base particles are preferably base particles other than metal particles, and more preferably resin particles, inorganic particles other than metal particles, or organic-inorganic hybrid particles.
  • the base particles may be core-shell particles having a core and a shell disposed on the surface of the core.
  • the core may be an organic core, and the shell may be an inorganic shell.
  • the above-mentioned base particles are more preferably resin particles or organic-inorganic hybrid particles, and may be either resin particles or organic-inorganic hybrid particles. By using these preferred base particles, the effects of the present invention are more effectively exhibited.
  • the material for the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyether ether ketone, polyether sulfone, divinylbenzene polymer, and polymers obtained by polymerizing one or more of various polymeriz
  • the divinylbenzene polymer may be a divinylbenzene copolymer.
  • examples of the divinylbenzene copolymer include divinylbenzene-styrene copolymer and divinylbenzene-(meth)acrylic acid ester copolymer.
  • the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having multiple ethylenically unsaturated groups.
  • examples of the polymerizable monomer having an ethylenically unsaturated group include non-crosslinkable monomers and crosslinkable monomers.
  • non-crosslinkable monomers include styrene-based monomers such as styrene and ⁇ -methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; alkyl (meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; 2-hydroxyethyl Examples of such monomers include oxygen-containing (meth)acrylate compounds such as (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and
  • crosslinkable monomers 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)propane tri ...
  • the resin particles can be obtained by polymerizing the polymerizable monomer having the ethylenically unsaturated group by a known method. Examples of such methods include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of using non-crosslinked seed particles to swell and polymerize the monomer together with a radical polymerization initiator.
  • the base particles are inorganic particles other than metal particles or organic-inorganic hybrid particles
  • examples of the inorganic material of the base particles include silica, alumina, barium titanate, zirconia, and carbon black. It is preferable that the inorganic material is not a metal.
  • the particles formed from silica are not particularly limited, but examples include particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, and then baking the particles as necessary.
  • the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed from a crosslinked alkoxysilyl polymer and an acrylic resin.
  • the organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core.
  • the core is preferably an organic core.
  • the shell is preferably an inorganic shell.
  • the base particle is preferably an organic-inorganic hybrid particle having an organic core and an inorganic shell disposed on the surface of the organic core.
  • Examples of the organic core material include the resin particle materials mentioned above.
  • the material of the inorganic shell may be any of the inorganic substances listed as the material of the base particle described above.
  • the material of the inorganic shell is preferably silica.
  • the inorganic shell is preferably formed by forming a shell-like material from a metal alkoxide on the surface of the core by a sol-gel method, and then firing the shell-like material.
  • the metal alkoxide is preferably a silane alkoxide.
  • the inorganic shell is preferably formed from a silane alkoxide.
  • the base particles are metal particles
  • examples of the metal particles include silver, copper, nickel, silicon, gold, titanium, and alloys such as solder.
  • the particle diameter of the base particles is preferably 0.01 ⁇ m or more, more preferably 0.05 ⁇ m or more, even more preferably 0.5 ⁇ m or more, even more preferably 1 ⁇ m or more, and particularly preferably 3 ⁇ m or more, and is preferably 50 ⁇ m or less, more preferably 30 ⁇ m or less, even more preferably 20 ⁇ m or less, and particularly preferably 10 ⁇ m or less.
  • the particle diameter of the base particles is equal to or greater than the lower limit, the electrical conductivity reliability is further increased.
  • aggregation is less likely to occur, and aggregated conductive particles are less likely to be formed.
  • the conductive particles are easily compressed sufficiently, and the connection resistance between the electrodes connected via the conductive particles can be further effectively reduced.
  • the particle diameter of the base particles is preferably an average particle diameter, and more preferably a number average particle diameter.
  • the number average particle diameter of the base particles can be measured, for example, as follows.
  • the conductive particles are added to "Technovit 4000" manufactured by Kulzer so that the content of the conductive particles is 30% by weight, and dispersed to prepare an embedded resin body for inspecting base particles.
  • a cross section of the conductive particles dispersed in the embedded resin body for inspecting base particles is cut out using an ion milling device ("IM4000" manufactured by Hitachi High-Technologies Corporation) so as to pass through the vicinity of the center of the base particle in the conductive particles dispersed in the embedded resin body for inspecting base particles.
  • IM4000 manufactured by Hitachi High-Technologies Corporation
  • the image magnification is set to 25,000 times, 50 conductive particles are randomly selected, and the base particle of each conductive particle is observed. The particle diameter of the base particle in each conductive particle is measured, and the arithmetic average is taken to determine the average particle diameter of the base particles.
  • FE-SEM field emission scanning electron microscope
  • the conductive portion preferably contains a metal.
  • the metal constituting the conductive portion is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, ruthenium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, as well as alloys thereof.
  • tin-doped indium oxide (ITO) may be used as the metal. Only one of the metals may be used, or two or more of them may be used in combination. From the viewpoint of further reducing the connection resistance between the electrodes, an alloy containing tin, nickel, palladium, ruthenium, silver, copper, or gold is preferred, and nickel or palladium is more preferred.
  • the conductive portion contains nickel, and it is even more preferable that the outer surface portion of the conductive portion contains nickel.
  • the nickel content in 100% by weight of the nickel-containing conductive part is preferably 10% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, even more preferably 70% by weight or more, and particularly preferably 90% by weight or more.
  • the nickel content in 100% by weight of the nickel-containing conductive part may be 99% by weight or less, 90% by weight or less, or 70% by weight or less.
  • the conductive portion may be formed of one layer.
  • the conductive portion may be formed of multiple layers. That is, the conductive portion may have a laminated structure of two or more layers.
  • the metal constituting the outermost layer is preferably an alloy containing gold, silver, nickel, palladium, ruthenium, copper, or tin, and is more preferably nickel.
  • the connection resistance between the electrodes is further reduced.
  • the method for forming the conductive portion on the surface of the base particle is not particularly limited.
  • Examples of the method for forming the conductive portion include electroless plating, electroplating, physical collision, mechanochemical reaction, physical vapor deposition or physical adsorption, and coating the surface of the base particle with a metal powder or a paste containing a metal powder and a binder.
  • the method for forming the conductive portion is preferably electroless plating, electroplating, or physical collision.
  • Examples of the physical vapor deposition method include vacuum vapor deposition, ion plating, and ion sputtering.
  • a sheeter composer manufactured by Tokuju Kosakusho Co., Ltd. is used.
  • the thickness of the conductive portion is preferably 0.005 ⁇ m or more, more preferably 0.01 ⁇ m or more, and is preferably 10 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 0.3 ⁇ m or less.
  • the thickness of the conductive portion is equal to or greater than the lower limit and equal to or less than the upper limit, sufficient conductivity is obtained, and the conductive particles do not become too hard, allowing the conductive particles to be sufficiently deformed when connected.
  • the thickness of the conductive portion of the outermost layer is preferably 0.001 ⁇ m or more, more preferably 0.01 ⁇ m or more, and preferably 0.5 ⁇ m or less, more preferably 0.1 ⁇ m or less.
  • the thickness of the conductive portion of the outermost layer is equal to or greater than the lower limit and equal to or less than the upper limit, the conductive portion of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes can be sufficiently low.
  • the thickness of the conductive portion can be measured, for example, by observing the cross-section of the conductive particle using a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the conductive particles preferably have a plurality of protrusions on the outer surface of the conductive part.
  • An oxide film is often formed on the surface of the electrodes connected by the conductive particles.
  • the oxide film can be effectively removed by the protrusions by arranging the conductive particles between the electrodes and pressing them together. This allows the electrodes and the conductive part to be in more reliable contact, and the connection resistance between the electrodes is further reduced.
  • the protrusions of the conductive particles can effectively remove the filler between the conductive particles and the electrodes. This further increases the reliability of the conduction between the electrodes.
  • Methods for forming the above-mentioned protrusions include a method in which a core material is attached to the surface of a base particle and then a conductive portion is formed by electroless plating, and a method in which a conductive portion is formed on the surface of a base particle by electroless plating, then a core material is attached, and then a conductive portion is formed by electroless plating.
  • a method may be used in which, without using the above-mentioned core material, a conductive portion is formed on the base particle by electroless plating, plating is deposited in the form of protrusions on the surface of the conductive portion, and then a conductive portion is formed by electroless plating.
  • Methods for attaching a core substance to the surface of a base particle include, for example, a method in which a core substance is added to a dispersion liquid of the base particle, and the core substance is accumulated and attached to the surface of the base particle by van der Waals forces, and a method in which a core substance is added to a container containing the base particle, and the core substance is attached to the surface of the base particle by mechanical action such as rotating the container.
  • the method for attaching a core substance to the surface of a base particle is preferably a method in which the core substance is accumulated and attached to the surface of the base particle in the dispersion liquid.
  • the materials constituting the core material include conductive materials and non-conductive materials.
  • the conductive materials include, for example, conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers.
  • the conductive polymers include polyacetylene.
  • the non-conductive materials include silica, alumina, titanium oxide, tungsten carbide, and zirconia. From the viewpoint of further increasing the reliability of electrical conduction between the electrodes, it is preferable that the core material is a metal.
  • the metal is not particularly limited.
  • the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, and cadmium, as well as alloys composed of two or more metals, such as tin-lead alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and tungsten carbide.
  • the metal is preferably nickel, copper, silver, or gold.
  • the metal may be the same as or different from the metal constituting the conductive portion.
  • the shape of the core material is not particularly limited.
  • the core material is preferably in the form of a mass.
  • Examples of the core material include particulate masses, agglomerates of multiple microparticles, and amorphous masses.
  • the particle diameter (average particle diameter) of the core material is preferably 0.001 ⁇ m or more, more preferably 0.05 ⁇ m or more, and preferably 0.9 ⁇ m or less, more preferably 0.2 ⁇ m or less.
  • the particle diameter of the core material is equal to or greater than the lower limit and equal to or less than the upper limit, the connection resistance between the electrodes can be effectively reduced.
  • the particle diameter of the core substance is preferably an average particle diameter, and more preferably a number average particle diameter.
  • the particle diameter of the core substance can be determined, for example, by observing 50 random core substances with an electron microscope or optical microscope and calculating the average particle diameter of each core substance, or by performing laser diffraction particle size distribution measurement.
  • the curing agent is preferably a polymerization initiator.
  • the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator.
  • the polymerization initiator may be used alone or in combination of two or more kinds.
  • the polymerization initiator contains a thermal polymerization initiator.
  • the thermal polymerization initiator preferably contains a thermal radical polymerization initiator, and is preferably a thermal radical polymerization initiator.
  • Examples of the thermal radical polymerization initiator include a peroxide radical polymerization initiator, an azo radical polymerization initiator, and a redox radical polymerization initiator.
  • azo radical polymerization initiator examples include azobisisobutyronitrile, azobiscyclohexanecarbonitrile, and azobisdimethylvaleronitrile.
  • the above-mentioned peroxide-based radical polymerization initiators include diacyl-based radical polymerization initiators, peroxyester-based radical polymerization initiators, dialkyl-based radical polymerization initiators, percarbonate-based radical polymerization initiators, and ketone peroxide-based radical polymerization initiators.
  • the above-mentioned diacyl-based radical polymerization initiators include lauroyl peroxide and benzoyl peroxide.
  • the above-mentioned peroxyester-based radical polymerization initiators include t-butyl peroxybenzoate, t-butyl peroxyacetate, t-butyl peroxypivalate, and t-butyl peroxy-2-ethylhexanoate.
  • the above-mentioned dialkyl-based radical polymerization initiators include dicumyl peroxide and di-t-butyl peroxide.
  • the above-mentioned percarbonate-based radical polymerization initiators include diisopropyl peroxydicarbonate.
  • the above-mentioned ketone peroxide-based radical polymerization initiators include methyl ethyl ketone peroxide.
  • the redox radical polymerization initiator includes, for example, a peroxide and a reducing agent or a metal-containing compound.
  • Specific examples of the redox radical polymerization initiator include a mixture of benzoyl peroxide and organic amines, a mixture of the peroxyester radical polymerization initiator and a reducing agent such as mercaptans, and a mixture of methyl ethyl ketone peroxide and an organic cobalt salt.
  • the above polymerization initiator contains a peroxide-based radical polymerization initiator.
  • the content of the curing agent (polymerization initiator) in 100% by weight of the conductive paste is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, and is preferably 5% by weight or less, more preferably 4% by weight or less, even more preferably 3% by weight or less.
  • the content of the curing agent (polymerization initiator) relative to 100 parts by weight of the curable compound in the conductive paste is preferably 0.3 parts by weight or more, more preferably 0.5 parts by weight or more, even more preferably 0.7 parts by weight or more, and is preferably 6 parts by weight or less, more preferably 5 parts by weight or less, and even more preferably 4 parts by weight or less.
  • content of the curing agent (polymerization initiator) is equal to or more than the lower limit and equal to or less than the upper limit, reactivity and storage stability can be improved.
  • the conductive paste may contain components other than the curable compound, the curing agent, and the plurality of conductive fillers, such as a solvent, an inorganic filler, an organic filler, a colorant, a polymerization inhibitor, a chain transfer agent, an antioxidant, an ultraviolet absorber, a defoaming agent, a leveling agent, a surfactant, a slip agent, an antiblocking agent, a wax, a masking agent, a deodorant, a fragrance, a preservative, an antibacterial agent, an antistatic agent, and an adhesion imparting agent.
  • a solvent such as a solvent, an inorganic filler, an organic filler, a colorant, a polymerization inhibitor, a chain transfer agent, an antioxidant, an ultraviolet absorber, a defoaming agent, a leveling agent, a surfactant, a slip agent, an antiblocking agent, a wax, a masking agent, a deodorant, a fragrance, a pre
  • the RFID inlay according to the present invention comprises a substrate having wiring on its surface, a chip having electrodes on its surface, and an adhesive portion bonding the substrate and the chip.
  • the material of the adhesive portion is the conductive paste described above.
  • the wiring and the electrodes are electrically connected by the conductive filler in the adhesive portion.
  • FIG. 1 is a cross-sectional view showing a schematic diagram of an RFID inlay using a conductive paste according to a first embodiment of the present invention.
  • the RFID inlay 81 shown in FIG. 1 comprises a substrate 82 having wiring on its surface, a chip 83 having electrodes on its surface, and an adhesive portion 84 that bonds the substrate 82 and the chip 83.
  • the material of the adhesive portion 84 is a conductive paste containing conductive filler 1.
  • the adhesive portion 84 is formed from a conductive paste containing conductive filler 1. It is preferable that the adhesive portion 84 is formed by hardening the conductive paste containing conductive filler 1.
  • the substrate 82 has wiring 82a on its surface (upper surface).
  • the chip 83 has an electrode 83a on its surface (lower surface).
  • the wiring 82a and the electrode 83a are electrically connected by the conductive filler 1 in the adhesive portion 84.
  • the manufacturing method of the RFID inlay according to the present invention comprises the following steps (1) to (3): (1) A first arrangement step of arranging the above-mentioned conductive paste on the surface of a substrate having wiring on its surface. (2) A second arrangement step of arranging a chip having an electrode on its surface on the surface of the conductive paste opposite the substrate. (3) A bonding step of forming an adhesive part that bonds the substrate and the chip with the conductive paste by heating and pressurizing the conductive paste, and electrically connecting the wiring and the electrodes with the conductive filler in the adhesive part.
  • the RFID inlay and manufacturing method for the RFID inlay according to the present invention use a specific conductive paste, which improves adhesion between the substrate and the chip and increases the reliability of electrical continuity.
  • the substrate is long and that the RFID inlay is manufactured by transporting the long substrate using a roll-to-roll method in the first arrangement step, the second arrangement step, and the bonding step.
  • multiple RFID inlays can be manufactured continuously, and the manufacturing efficiency of the RFID inlay can be further improved.
  • the conductive paste can be applied by, for example, applying it with a dispenser, screen printing, or ejecting it with an inkjet device.
  • the heating temperature in the bonding process is preferably 100°C or higher, more preferably 150°C or higher, and is preferably 400°C or lower, more preferably 300°C or lower, and even more preferably 250°C or lower. If the heating temperature in the bonding process is equal to or higher than the lower limit and equal to or lower than the upper limit, good electrical connection between the chip and the wiring (antenna pattern) can be achieved.
  • the applied pressure in the bonding process is preferably 0.5 N or more, more preferably 1 N or more, and is preferably 3.5 N or less, more preferably 3 N or less, and even more preferably 2.5 N or less.
  • the applied pressure in the bonding process is equal to or more than the lower limit and equal to or less than the upper limit, the adhesion between the substrate and the chip can be improved, and the electrical conductivity reliability can be improved.
  • the heating and pressurizing time in the bonding process is not particularly limited.
  • the heating and pressurizing time in the bonding process may be 2 seconds or more, 15 seconds or less, or 10 seconds or less.
  • the RFID inlay may be cut to a predetermined size as necessary, or may be cut before use. It is preferable that a plurality of the chips are adhered to a long substrate by a plurality of the adhesive parts. A plurality of laminates of the chips and the adhesive parts may be arranged on the long substrate. In the first arrangement step, it is preferable that the conductive paste is arranged at a plurality of locations on the surface of the long substrate. In the second arrangement step, it is preferable that the chips are arranged using a plurality of chips on the surface opposite the substrate side of each of the conductive pastes arranged at a plurality of locations. After the chips are adhered to the long substrate by the adhesive parts, the long substrate may be cut.
  • the substrate is not particularly limited.
  • the substrate is preferably a circuit board.
  • the circuit board include a resin film, a flexible printed circuit board, a rigid-flexible board, a glass board, and a paper board.
  • the base material may be a resin board, a glass board, or a paper board.
  • the substrate has wiring (antenna pattern) on its surface.
  • the substrate has wiring (antenna pattern) formed on its surface.
  • the substrate preferably has a substrate and wiring (antenna pattern) disposed on the surface of the substrate.
  • the substrate may be made of resin, glass, paper, or the like.
  • the resin may be made of PET (polyethylene terephthalate), PP (polypropylene), PVC (polyvinyl chloride), or the like.
  • the paper may be impregnated with epoxy resin or phenolic resin.
  • the substrate is preferably made of resin or paper, and more preferably made of PET (polyethylene terephthalate) or paper.
  • the substrate may be made of resin, glass, or paper.
  • the above wiring may be gold wiring, nickel wiring, tin wiring, aluminum wiring, silver wiring, SUS wiring, copper wiring, molybdenum wiring, tungsten wiring, etc. From the viewpoint of improving the operating sensitivity in the UHF band (860 MHz to 920 MHz), the above wiring is preferably aluminum wiring.
  • the thickness of the substrate is preferably 20 ⁇ m or more, more preferably 30 ⁇ m or more, and is preferably 200 ⁇ m or less, more preferably 100 ⁇ m or less.
  • the shapes of the substrate and the base material are not particularly limited. From the viewpoint of manufacturing RFID inlays by a roll-to-roll method, it is preferable that the substrate and the base material are long.
  • the length of the substrate and the base material is not particularly limited. The length of the substrate and the base material may be 1 m or more, 10 m or more, 5000 m or less, or 1000 m or less.
  • the surface tension of the substrate (base material) is preferably 30 mN/m or more, more preferably 32 mN/m or more, even more preferably 34 mN/m or more, and is preferably 50 mN/m or less, more preferably 48 mN/m or less, even more preferably 45 mN/m or less. If the surface tension of the substrate (base material) is equal to or more than the lower limit and equal to or less than the upper limit, the adhesiveness can be further improved.
  • the conductive paste of the present invention can be suitably used for application to a substrate (base material) having a surface tension equal to or more than the lower limit and equal to or less than the upper limit.
  • the surface tension of the above substrate (base material) can be measured in accordance with JIS K6768 using the following method. A cotton swab is dipped in the JIS-specified liquid and applied to the substrate (base material). The surface tension is determined from the shape of the coating two seconds after application.
  • the above chips include semiconductor chips (IC chips), etc.
  • the chip has an electrode on its surface.
  • the electrode include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, silver electrodes, SUS electrodes, copper electrodes, molybdenum electrodes, and tungsten electrodes. From the viewpoint of further improving the reliability of electrical conduction, the electrode is preferably a copper electrode or a gold electrode, and more preferably a copper electrode.
  • the number of electrodes per chip is not particularly limited.
  • the number of electrodes per chip may be 1 or more, 4 or more, 20 or less, or 10 or less.
  • the shape of the tip is not particularly limited.
  • the tip may be rectangular, triangular, or circular.
  • the plane area of the chip is preferably 0.04 mm2 or more, more preferably 0.09 mm2 or more, even more preferably 0.16 mm2 or more, and is preferably 0.50 mm2 or less, more preferably 0.40 mm2 or less, even more preferably 0.30 mm2 or less.
  • the conductive paste can be arranged on the fine wiring with high precision.
  • the RFID inlay can maintain the conductivity reliability even when it is left in a high-temperature and high-humidity environment for a long time.
  • the conductive paste according to the present invention can be suitably used for bonding relatively small chips.
  • Curable Compounds Isobornyl acrylate ((A) polymerizable monomer, molecular weight: 208) Polyester urethane acrylate ("UN-353” manufactured by Negami Chemical Industries, Ltd., molecular weight (weight average molecular weight): 5000) Tricyclodecane dimethanol diacrylate ("IRR214" manufactured by Daicel Allnex Corporation, molecular weight: 304) Trimethylolpropane triacrylate (“A-TMPT” manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight: 296) Epoxy resin half acrylate (“EBECRYL3605" manufactured by Daicel Allnex Co., Ltd., molecular weight: 450) N-Acryloyloxyethylhexahydrophthalimide ("M-140" manufactured by Toagosei Co., Ltd., molecular weight: 251)
  • Conductive filler "NIELB-005-S” manufactured by Sekisui Chemical Co., Ltd. (conductive particles having a base particle and a conductive portion on the surface of the base particle, nickel content in 100% by weight of the conductive portion: 52% by weight, average particle size: 5 ⁇ m)
  • Inorganic filler Silica ("KE-S100” manufactured by Nippon Shokubai Co., Ltd.)
  • Tips IC chip (copper electrode, NXP "UCODE7", surface area: 0.22 mm 2 )
  • PET film long, resin film with aluminum wiring and operating frequency in the UHF band (860 MHz to 920 MHz), surface tension: 43 mN/m
  • Example 1 Preparation of Conductive Paste The materials shown in Table 1 below were mixed in the amounts shown in Table 1 below and stirred using a planetary mixer (Thinky Mixer), to obtain a conductive paste (anisotropic conductive paste).
  • a planetary mixer Thinky Mixer
  • connection step the wiring on the surface of the PET film and the electrodes on the surface of the chip were electrically connected by the conductive filler (conductive particles) in the adhesive part to obtain a connection structure (adhesion step).
  • the first arrangement step, the second arrangement step, and the adhesion step were performed using a "DDA40000" (roll-to-roll method) manufactured by Muhlbauer.
  • the resulting connection structure was cut to a size of 5 cm x 1.5 cm using a "DCL30000” manufactured by Muhlbauer, to obtain 50 RFID inlays.
  • Examples 2 to 9 and Comparative Examples 1 to 3 A conductive paste and an RFID inlay were obtained in the same manner as in Example 1, except that the ingredients and amounts of the conductive paste were changed as shown in Tables 1, 3, and 5.
  • Discharge stability by jet dispenser A discharge test of the obtained conductive paste was carried out using an inkjet dispenser (MDS-3200 manufactured by Vermes). The discharge stability of the conductive paste by the jet dispenser was judged according to the following criteria. Note that “stable discharge” means that no liquid pool occurs when the conductive paste is discharged, and there is no change in the amount of droplets discharged.
  • ⁇ The absolute value of the difference in peak sensitivity of all RFID inlays is less than 2 dBm. ⁇ : Does not fall under either ⁇ or ⁇ . ⁇ : The absolute value of the difference in initial peak sensitivity of at least one RFID inlay is 3 dBm or more.
  • REFERENCE SIGNS LIST 1 conductive filler 81
  • RFID inlay 82 ...substrate having wiring on its surface 82a
  • wiring 83 ...chip having electrode on its surface 83a

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WO2025089237A1 (ja) * 2023-10-24 2025-05-01 株式会社レゾナック 接着剤組成物、接続構造体、及び接続構造体の製造方法
WO2026009765A1 (ja) * 2024-07-01 2026-01-08 積水化学工業株式会社 導電ペースト、ｒｆｉｄインレイ及びｒｆｉｄインレイの製造方法

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WO2018181694A1 (ja) * 2017-03-30 2018-10-04 積水化学工業株式会社 導電性粒子、導電材料及び接続構造体
WO2018230470A1 (ja) * 2017-06-12 2018-12-20 積水化学工業株式会社 樹脂粒子、導電性粒子、導電材料、接着剤、接続構造体及び液晶表示素子
WO2020054288A1 (ja) * 2018-09-14 2020-03-19 積水化学工業株式会社 導電材料及び接続構造体
WO2020230842A1 (ja) * 2019-05-14 2020-11-19 積水化学工業株式会社 樹脂粒子、導電性粒子、導電材料及び接続構造体

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WO2018181694A1 (ja) * 2017-03-30 2018-10-04 積水化学工業株式会社 導電性粒子、導電材料及び接続構造体
WO2018230470A1 (ja) * 2017-06-12 2018-12-20 積水化学工業株式会社 樹脂粒子、導電性粒子、導電材料、接着剤、接続構造体及び液晶表示素子
WO2020054288A1 (ja) * 2018-09-14 2020-03-19 積水化学工業株式会社 導電材料及び接続構造体
WO2020230842A1 (ja) * 2019-05-14 2020-11-19 積水化学工業株式会社 樹脂粒子、導電性粒子、導電材料及び接続構造体

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025089237A1 (ja) * 2023-10-24 2025-05-01 株式会社レゾナック 接着剤組成物、接続構造体、及び接続構造体の製造方法
WO2026009765A1 (ja) * 2024-07-01 2026-01-08 積水化学工業株式会社 導電ペースト、ｒｆｉｄインレイ及びｒｆｉｄインレイの製造方法

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