KR102545861B1 - Conductive material - Google Patents

Abstract

A conductive material from which excellent conduction reliability can be obtained with respect to an oxide layer. The conductive material includes resin core particles 10, insulating particles 20 arranged in plurality on the surface of the resin core particles 10 to form projections 30a, resin core particles 10 and insulating particles 20 ), and the Mohs hardness of the insulating particle 20 contains electrically conductive particle larger than 7. As a result, the conductive particles penetrate the oxide layer on the surface of the electrode and penetrate sufficiently, and excellent conduction reliability is obtained.

Description

Conductive material {CONDUCTIVE MATERIAL}

The present invention relates to a conductive material that electrically connects circuit members to each other. This application claims priority based on Japanese Patent Application No. 2014-220448, filed on October 29, 2014, and Japanese Patent Application No. 2015-201767, filed on October 13, 2015 in Japan. The application is incorporated herein by reference.

In recent years, IZO (Indium Zinc Oxide) has been used as wiring for circuit members instead of ITO (Indium Tin Oxide), which is expensive to produce. The surface of the IZO wiring is smooth, and an oxide layer (passive state) is formed on the surface. Further, for example, in aluminum wiring, a protective layer of an oxide layer such as TiO ₂ may be formed on the surface to prevent corrosion.

However, since the oxide layer is hard, in conventional conductive materials, conductive particles do not penetrate the oxide layer sufficiently, and sufficient conduction reliability cannot be obtained in some cases.

Japanese Unexamined Patent Publication No. 2013-149613

The present invention has been proposed in view of such a conventional situation, and provides a conductive material capable of obtaining excellent conduction reliability with respect to an oxide layer.

As a result of intensive studies, the present inventors have found that excellent conduction resistance can be obtained by setting the Mohs hardness of the insulating particles forming the protrusions of the conductive particles to be larger than a predetermined value.

That is, the conductive material according to the present invention includes resin core particles, insulating particles arranged in plurality on the surface of the resin core particles to form projections, and a conductive layer arranged on the surfaces of the resin core particles and the insulating particles. It is characterized in that it contains conductive particles having a Mohs hardness of the insulating particles greater than 7.

Further, the bonded structure according to the present invention includes resin core particles, insulating particles arranged in plurality on the surface of the resin core particles to form projections, and a conductive layer arranged on the surfaces of the resin core particles and the insulating particles. and the terminal of the first circuit member and the terminal of the second circuit member are connected by conductive particles having a Mohs hardness of the insulating particles greater than 7.

Further, the method for manufacturing a bonded structure according to the present invention includes resin core particles, insulating particles arranged in plurality on the surface of the resin core particles to form protrusions, and arranged on the surfaces of the resin core particles and the insulating particles. A conductive layer is provided, and the terminal of the first circuit member and the terminal of the second circuit member are crimped through a conductive material containing conductive particles having a Mohs hardness of more than 7 of the insulating particles.

According to the present invention, since the Mohs hardness of the insulating particles forming the projections is large, the conductive particles penetrate the oxide layer on the surface of the electrode sufficiently to penetrate, and excellent conduction reliability is obtained.

1 is a cross-sectional view schematically illustrating a first structural example of conductive particles.
2 is a cross-sectional view schematically illustrating a second structural example of conductive particles.
3 is a cross-sectional view schematically illustrating a third structural example of conductive particles.
4 is a cross-sectional view schematically illustrating conductive particles at the time of crimping.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail in the following order, referring drawings.

1. Conductive Particles

2. Challenge material

3. Manufacturing method of connection structure

4. Examples

<1. Conductive Particles>

The conductive particle according to the present embodiment includes a resin core particle, a plurality of insulating particles disposed on the surface of the resin core particle to form projections, and a conductive layer disposed on the resin core particle and the surface of the insulating particle, The Mohs hardness of the insulating particles is greater than 7. As a result, the conductive particles penetrate the oxide layer on the surface of the electrode and penetrate sufficiently, and excellent conduction reliability is obtained. In particular, when the circuit member as an adherend is a plastic substrate with a low elastic modulus such as a PET (Poly Ethylene Terephthalate) substrate, the effect of deformation of the substrate can be reduced without increasing the pressure during compression, so that low resistance can be realized. Valid.

[First configuration example]

1 is a cross-sectional view schematically illustrating a first structural example of conductive particles. The conductive particles of the first structural example include resin core particles 10, insulating particles 20 attached to the surface of the resin core particles 10 in plural numbers and serving as core materials of the projections 30a, and resin core particles 10 and a conductive layer (30) covering the insulating particles (20).

Examples of the resin core particles 10 include benzoguanamine resins, acrylic resins, styrene resins, silicone resins, polybutadiene resins, and the like, and at least two or more types of repeating units based on monomers constituting these resins. and copolymers having combined structures. Among these, it is preferable to use a copolymer obtained by combining divinylbenzene, tetramethylolmethane tetraacrylate and styrene.

Moreover, it is preferable that the compressive elastic modulus (20% K value) of the resin core particle 10 when compressed by 20% is 500-20000 N/mm<2>. When the 20% K value of the resin core particle 10 is within the above range, as a result, the projections can penetrate the oxide layer on the surface of the electrode. For this reason, an electrode and the conductive layer of electroconductive particle fully contact, and connection resistance between electrodes can be reduced.

The compressive modulus (20% K value) of the resin core particles 10 can be measured as follows. Using a micro compression tester, conductive particles are compressed in a smooth indenter cross section of circumference (50 μm in diameter, made of diamond) under conditions of a compression rate of 2.6 mN/sec and a maximum test load of 10 gf. The load value (N) and compression displacement (mm) at this time are measured. From the obtained measured values, the compressive modulus (20% K value) can be obtained by the following formula. In addition, as a micro-compression tester, "Fisher Scope H-100" by Fischer, etc. is used, for example.

K value (N/㎟) = (3/2 ^1/2 ) F S ^-3/2 R R ^-1/2

F: Load value when conductive particles are compressed and deformed by 20% (N)

S: Compression displacement (mm) when conductive particles are compressed and deformed by 20%

R: Radius of conductive particles (mm)

It is preferable that the average particle diameter of the resin core particle 10 is 2-10 micrometers. In this specification, the average particle diameter means the particle diameter (D50) at 50% of the integrated value in the particle size distribution determined by the laser diffraction/scattering method.

A plurality of insulating particles 20 are attached to the surface of the resin core particle 10 and serve as a core material for the protrusion 30a for piercing the oxide layer on the surface of the electrode. The insulating particle 20 has a Mohs hardness greater than 7, and it is preferable that it is 9 or more. When the hardness of the insulating particle 20 is high, the protrusion 30a can pierce the oxide on the surface of the electrode. Moreover, compared with the case where electroconductive particle is used because the core material of processus|protrusion 30a is the insulating particle 20, the factor of migration is reduced.

As the insulating particle 20, zirconia (Mohs hardness 8-9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10), etc. are mentioned, These may be used independently, You may use it combining two or more types. Among these, it is preferable to use alumina from a viewpoint of economical efficiency.

In addition, the average particle diameter of the insulating particles 20 is preferably 50 nm or more and 250 nm or less, more preferably 100 nm or more and 200 nm or less. Moreover, the number of projections formed on the surface of the resin core particle 20 is preferably 1 to 500, more preferably 30 to 200. By forming a predetermined number of protrusions 30a on the surface of the resin core particle 20 using insulating particles 20 having such an average particle diameter, the protrusions 30a pierce the oxide on the surface of the electrode, thereby reducing the connection resistance between the electrodes. can be effectively lowered.

The conductive layer 30 covers the resin core particles 10 and the insulating particles 20 and has projections 30a raised by the plurality of insulating particles 20 . The conductive layer 30 is preferably nickel or a nickel alloy. As a nickel alloy, Ni-W-B, Ni-W-P, Ni-W, Ni-B, Ni-P, etc. are mentioned. Among these, it is preferable to use low-resistance Ni-W-B.

Moreover, the thickness of the conductive layer 30 is preferably 50 nm or more and 250 nm or less, more preferably 80 nm or more and 150 nm or less. When the thickness of the conductive layer 30 is too small, it becomes difficult to make it function as conductive particles, and when the thickness is too large, the height of the protrusion 30a disappears.

The electroconductive particle of the 1st structural example can be obtained by the method of forming the conductive layer 30 after making the insulating particle 20 adhere to the surface of the resin core particle 10. In addition, as a method of depositing the insulating particles 20 on the surface of the resin core particles 10, for example, adding the insulating particles 20 to a dispersion of the resin core particles 10, and then adding the resin core particles The insulating particle 20 is accumulated and adhered to the surface of (10) by, for example, van der Waals force. Moreover, as a method of forming a conductive layer, the method by electroless plating, the method by electroplating, the method by physical vapor deposition, etc. are mentioned, for example. Among these, the method by electroless plating which is easy to form a conductive layer is preferable.

[Second configuration example]

2 is a cross-sectional view schematically illustrating a second structural example of conductive particles. The conductive particles of the second structural example include resin core particles 10, insulating particles 20 attached to the surface of the resin core particles 10 in plural numbers and serving as core materials for the projections 32a, and resin core particles 10 And the 1st conductive layer 31 which coat|covers the surface of the insulating particle 20, and the 2nd conductive layer 32 which coat|covers the conductive layer 31 are provided. That is, in the second configuration example, the conductive layer 30 of the first configuration example has a two-layer structure. By making the conductive layer a two-layer structure, the adhesion of the second conductive layer 32 constituting the outermost shell can be improved, and the conduction resistance can be reduced.

Since the resin core particles 10 and the insulating particles 20 are the same as those in the first structural example, descriptions thereof are omitted here.

The first conductive layer 31 covers the surfaces of the resin core particles 10 and the insulating particles 20 and serves as a base for the second conductive layer 32 . It will not specifically limit as long as the adhesiveness of the 2nd conductive layer 32 improves as 1st conductive layer 31, For example, nickel, a nickel alloy, copper, silver etc. are mentioned.

The second conductive layer 32 covers the first conductive layer 31 and has projections 32a raised by a plurality of insulating particles 20 . It is preferable that the 2nd conductive layer 32 is nickel or a nickel alloy similarly to the 1st structural example. As a nickel alloy, Ni-W-B, Ni-W-P, Ni-W, Ni-B, Ni-P, etc. are mentioned. Among these, it is preferable to use low-resistance Ni-W-B.

In addition, the total thickness of the first conductive layer 31 and the second conductive layer 32 is the same as that of the conductive layer 30 of the first configuration example, preferably 50 nm or more and 250 nm or less, more preferably 80 nm. nm or more and 150 nm or less. When the total thickness is too small, it becomes difficult to function as conductive particles, and when the total thickness is too large, the height of the projections 32a disappears.

The method of forming the second conductive layer 32 after the insulating particle 20 is adhered to the surface of the resin core particle 10, the first conductive layer 31 is formed, and then the conductive particle of the second structural example is formed. can be obtained by Further, as a method of adhering the insulating particles 20 on the surface of the resin core particles 10, for example, adding the insulating particles 20 to a dispersion of the resin core particles 10, and then adding the resin core particles ( 10), the insulating particles 20 are accumulated and adhered to the surface by, for example, van der Waals force. Moreover, as a method of forming the 1st conductive layer 31 and the 2nd conductive layer 32, the method by electroless plating, the method by electroplating, the method by physical vapor deposition, etc. are mentioned, for example. there is. Among these, the method by electroless plating which is easy to form a conductive layer is preferable.

[Example of the 3rd configuration]

3 is a cross-sectional view schematically illustrating a third structural example of conductive particles. The conductive particles of the third structural example are adhered in plurality to the resin core particles 10, the first conductive layer 33 covering the surface of the resin core particle 10, and the surface of the first conductive layer 33, Insulating particles 20 serving as the core of the protrusion 34a, a first conductive layer 33, and a second conductive layer 34 covering the surfaces of the insulating particles 20 are provided. That is, the 3rd structural example is what made the insulating particle 20 adhere to the surface of the 1st conductive layer 33, and also formed the 2nd conductive layer 34. This prevents the insulating particles 20 from penetrating into the resin core particles 10 during compression, so that the projections can easily pierce the oxide layer on the surface of the electrode.

Since the resin core particles 10 and the insulating particles 20 are the same as those in the first structural example, descriptions thereof are omitted here.

The 1st conductive layer 33 covers the surface of the resin core particle 10, and becomes the adhesion surface of the insulating particle 20 and the base of the 2nd conductive layer 34. It will not specifically limit as long as the adhesiveness of the 2nd conductive layer 34 improves as 1st conductive layer 33, For example, nickel, a nickel alloy, copper, silver etc. are mentioned.

In addition, the thickness of the first conductive layer 33 is preferably 10 nm or more and 200 nm or less, more preferably 50 nm or more and 150 nm or less. Since the effect of elasticity of the resin core particle 10 will fall when thickness is too large, conduction reliability will fall.

The second conductive layer 34 covers the insulating particles 20 and the first conductive layer 33 and has projections 34a raised by the plurality of insulating particles 20 . It is preferable that the 2nd conductive layer 34 is nickel or a nickel alloy similarly to the 1st structural example. As a nickel alloy, Ni-W-B, Ni-W-P, Ni-W, Ni-B, Ni-P, etc. are mentioned. Among these, it is preferable to use low-resistance Ni-W-B.

In addition, the thickness of the second conductive layer 34 is preferably 50 nm or more and 250 nm or less, more preferably 80 nm or more and 150 nm or less, similarly to the conductive layer 30 of the first structural example. When the total thickness is too small, it becomes difficult to function as conductive particles, and when the total thickness is too large, the height of the projections 34a disappears.

The conductive particle of the third configuration example is a method in which the first conductive layer 33 is formed on the surface of the resin core particle 10, and then the insulating particle 20 is attached to form the second conductive layer 34. can be obtained by In addition, as a method of adhering the insulating particles 20 on the surface of the first conductive layer 33, for example, in a dispersion of the resin core particles 10 on which the first conductive layer 33 is formed, the insulating particles (20) is added, and the insulating particle 20 is integrated and adhered to the surface of the first conductive layer 33 by, for example, van der Waals force. In addition, as a method of forming the 1st conductive layer 33 and the 2nd conductive layer 34, the method by electroless plating, the method by electroplating, the method by physical vapor deposition, etc. are mentioned, for example. there is. Among these, the method by electroless plating which is easy to form a conductive layer is preferable.

<2. conductive material>

The electrically-conductive material according to the present embodiment includes resin core particles, insulating particles disposed in a plurality on the surface of the resin core particles to form protrusions, and a conductive layer disposed on the surfaces of the resin core particles and the insulating particles, and has insulating properties. It contains electroconductive particle whose Mohs hardness is greater than 7. Examples of the conductive material include films and pastes, and examples thereof include an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP). Moreover, as a hardening type of an electrically-conductive material, a thermosetting type, a photocuring type, a light-heat combined use hardening type, etc. are mentioned.

Hereinafter, a thermosetting anisotropic conductive film having a two-layer structure in which an ACF layer containing conductive particles and a non-conductive film (NCF) layer containing no conductive particles are laminated will be described as an example. In addition, as a thermosetting type anisotropic conductive film, a cation-curing type, anion-curing type, a radical curing type, or these can be used together, for example, but an anion-curing type anisotropic conductive film is demonstrated here.

In the anion-curing type anisotropic conductive film, the ACF layer and the NCF layer contain a film-forming resin, an epoxy resin, and an anionic polymerization initiator as binders.

The film-forming resin corresponds to, for example, a high molecular weight resin having an average molecular weight of 10000 or more, and from the viewpoint of film formation, it is preferable that the average molecular weight is about 10000 to 80000. Examples of the film-forming resin include various resins such as phenoxy resins, polyester resins, polyurethane resins, polyester urethane resins, acrylic resins, polyimide resins, and butyral resins. These may be used alone, You may use it combining two or more types. Among these, it is preferable to use a phenoxy resin suitably from viewpoints of film formation state, connection reliability, etc.

The epoxy resin forms a three-dimensional network structure and imparts good heat resistance and adhesiveness, and it is preferable to use a solid epoxy resin and a liquid epoxy resin together. Here, the solid epoxy resin means an epoxy resin that is solid at room temperature. Moreover, a liquid epoxy resin means a liquid epoxy resin at normal temperature. In addition, normal temperature means the temperature range of 5-35 degreeC prescribed|regulated by JIS Z8703.

The solid epoxy resin is not particularly limited as long as it is compatible with liquid epoxy resin and is solid at room temperature, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional type epoxy resin, dicyclopentadiene type epoxy resin, novolac phenol A type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, etc. are mentioned, One type can be used individually or in combination of 2 or more types among these. Among these, it is preferable to use a bisphenol A type epoxy resin. As a specific example available on the market, Nippon Steel Sumikin Chemical Co., Ltd. trade name "YD-014", etc. are mentioned.

The liquid epoxy resin is not particularly limited as long as it is liquid at normal temperature, and examples thereof include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac phenol type epoxy resins, and naphthalene type epoxy resins. or two or more may be used in combination. In particular, it is preferable to use a bisphenol A type epoxy resin from the viewpoints of film tackiness, flexibility and the like. As a specific example available on the market, Mitsubishi Chemical Corporation's brand name "EP828" etc. are mentioned.

As the anionic polymerization initiator, a commonly used known curing agent can be used. For example, organic acid dihydrazide, dicyandiamide, amine compounds, polyamide amine compounds, cyanate ester compounds, phenolic resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, brens tedate salts, polymercaptan-based curing agents, urea resins, melamine resins, isocyanate compounds, block isocyanate compounds, and the like, and among these, one type may be used alone or in combination of two or more types. Among these, it is preferable to use a microcapsule type latent curing agent obtained by using an imidazole modified product as a nucleus and covering the surface with polyurethane. As a specific example available on the market, "Novacure 3941HP", a trade name of Asahi Kasei E-Materials Co., Ltd., etc. is mentioned.

Moreover, as a binder, you may mix|blend a stress reliever, a silane coupling agent, an inorganic filler, etc. as needed. Examples of the stress reliever include hydrogenated styrene-butadiene block copolymers and hydrogenated styrene-isoprene block copolymers. Moreover, as a silane coupling agent, an epoxy type, a methacryloxy type, an amino type, a vinyl type, a mercapto sulfide type, a ureide type, etc. are mentioned. Moreover, as an inorganic filler, a silica, a talc, a titanium oxide, a calcium carbonate, magnesium oxide, etc. are mentioned.

<3. Manufacturing Method of Connected Structure>

The method for manufacturing a bonded structure according to the present embodiment includes resin core particles, insulating particles arranged in plurality on the surfaces of the resin core particles to form protrusions, and a conductive layer arranged on the surfaces of the resin core particles and the insulating particles. And the terminal of the 1st circuit member and the terminal of a 2nd circuit member are crimped|bonded through the electrically-conductive material containing the electrically-conductive particle whose Mohs hardness of insulating particle is larger than 7. Thereby, the connection structure which the terminal of a 1st circuit member and the terminal of a 2nd circuit member are connected by the above-mentioned electroconductive particle can be obtained.

The first circuit member and the second circuit member are not particularly limited and can be appropriately selected according to the purpose. Examples of the first circuit member include plastic substrates, glass substrates, printed wiring boards (PWBs), and the like for LCD (Liquid Crystal Display) panel applications and plasma display panel (PDP) applications. Moreover, as a 2nd circuit member, flexible printed circuits (FPC: Flexible Printed Circuits), such as IC (Integrated Circuit) and COF (Chip On Film), a tape carrier package (TCP) board|substrate, etc. are mentioned, for example.

4 is a cross-sectional view schematically illustrating conductive particles at the time of crimping. In Fig. 4, the conductive layer is omitted. Since the conductive particles 40 have a plurality of insulating particles 42 forming projections arranged on the surface of the resin core particles 41, the oxide layer formed on the terminal 51 of the first circuit member 50 ( 52) becomes possible. The oxide layer 52 functions as a protective layer that prevents corrosion of wiring, and examples thereof include TiO ₂ , SnO ₂ , and SiO ₂ .

In the present embodiment, since the Mohs hardness of the insulating particles 41 is greater than 7, the oxide layer 52 can be pierced without increasing the pressure during crimping, and the occurrence of wiring cracks can be suppressed. In particular, when the first circuit member 50 is a plastic substrate with a low modulus of elasticity such as a PET (Poly Ethylene Terephthalate) substrate, low resistance can be realized by reducing the effect of deformation of the substrate without increasing the pressure during compression. Because of this, it is very effective. The modulus of elasticity of the plastic substrate can be determined by taking into account factors such as flexibility and flexibility required for the connection body and the relationship between the connection strength with electronic components such as the drive circuit element 3 described later. It becomes 2000 Mpa - 4100 Mpa.

In the crimping of the terminals of the first circuit member and the terminals of the second circuit member, the second circuit member is thermally pressed with a crimping tool heated to a predetermined temperature for a predetermined period of time to perform main crimping. Here, the predetermined pressure is preferably 10 MPa or more and 80 MPa or less from the viewpoint of preventing wiring cracks in circuit members. In addition, the predetermined temperature is the temperature of the anisotropic conductive film during compression, and is preferably 80°C or more and 230°C or less.

The crimping tool is not particularly limited and can be appropriately selected according to the purpose, and pressing may be performed once using a pressing member having a larger area than the pressing target, or pressing several times using a pressing member having a smaller area than the pressing target. You may carry out by dividing in sequence. The tip shape of the crimping tool is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include a flat shape and a curved shape. Further, when the shape of the tip is a curved surface, it is preferable to press along the curved surface.

Moreover, you may heat-compress by attaching a shock absorber between a crimping tool and a 2nd circuit member. By attaching with a buffer material interposed, while being able to reduce pressure variation, it is possible to prevent the crimping tool from being contaminated. The buffer material is made of a sheet-like elastic material or a plastic body, and for example, silicone rubber or polytetrafluoroethylene is used.

According to the manufacturing method of such a bonded structure, since the Mohs hardness of the insulating particles is large, the oxide layer can be pierced without increasing the pressure during crimping, and the occurrence of wiring cracks can be suppressed. In addition, by making the conductive layer of a material having a high hardness such as Ni-W-B, the oxide layer can be easily pierced without increasing the pressure at the time of crimping, and the occurrence of wiring cracks can be further suppressed.

Example

<3. Example>

Hereinafter, embodiments of the present invention will be described. In this example, conductive particles having protrusions were prepared, and a connected structure was prepared using an anisotropic conductive film containing the conductive particles. Then, the conduction resistance of the bonded structure and the incidence rate of wiring cracks were evaluated. In addition, this invention is not limited to these Examples.

Production of the anisotropic conductive film, production of the bonded structure, measurement of conduction resistance, and calculation of the occurrence rate of wiring cracks were performed as follows.

[Manufacture of anisotropic conductive film]

An anisotropic conductive film having a two-layer structure in which an ACF layer and an NCF layer are laminated was prepared. First, 20 parts by mass of phenoxy resin (YP50, Nippon Steel Chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP828, Mitsubishi Chemical Co., Ltd.), solid epoxy resin (YD-014, Nippon Steel Chemical Co., Ltd.) 10 parts by mass, 30 parts by mass of a microcapsule type latent curing agent (Novacure 3941H, Asahi Kasei E Materials), and 10 parts by mass of conductive particles were blended to obtain an ACF layer having a thickness of 6 µm. Next, 20 parts by mass of phenoxy resin (YP50, Nippon Steel Chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP828, Mitsubishi Chemical Co., Ltd.), solid epoxy resin (YD-014, Nippon Steel Chemical Co., Ltd.) ) 10 parts by mass and 30 parts by mass of a microcapsule type latent curing agent (Novacure 3941H, Asahi Kasei E-Materials) were blended to obtain an NCF layer having a thickness of 12 μm. Then, the ACF layer and the NCF layer were bonded together to obtain an anisotropic conductive film having a two-layer structure with a thickness of 18 µm.

[Manufacture of connection structure]

As evaluation substrates, TiO ₂ /Al coated glass substrate (0.3 mmt, TiO ₂ thickness: 50 nm, Al thickness: 300 nm), TiO ₂ /Al coated PET (Poly Ethylene Terephthalate) substrate (0.3 mmt, TiO ₂ thickness : 50 nm, Al thickness: 300 nm), and IC (1.8 mm × 20 mm, T: 0.3 mm, Au-plated bump: 30 μm × 85 μm, h = 15 μm) were prepared. In addition, the crimping conditions were 190°C-60 MPa-5 sec or 190°C-100 MPa-5 sec.

First, on a TiO ₂ /Al-coated glass substrate or on a TiO ₂ /Al-coated PET substrate, an anisotropic conductive film slit into a 1.5 mm width is temporarily adhered using a press, and after peeling off the peeling PET film, an IC is pressed with a press was used and crimped under predetermined crimping conditions to obtain a bonded structure.

[Measurement of conduction resistance]

The conduction resistance (Ω) of the initial connected structure was measured using a digital multimeter (trade name: Digital Multimeter 7561, manufactured by Yokogawa Electric Co., Ltd.). Moreover, after carrying out the reliability test by leaving the bonded structure to stand in a high-temperature, high-humidity environment of 85°C and 85%RH for 500 h, the conduction resistance (Ω) of the bonded structure was measured.

[Rate of wiring cracks]

Arbitrary 20 points of wiring on the substrate side of the bonded structure were observed with a metallographic microscope, and wiring cracks were counted to calculate the occurrence rate.

[Total judgment]

A case where the difference between the initial conduction resistance and the conduction resistance after the reliability test was 0.3 Ω or less, and the occurrence rate of wiring cracks was 0% was evaluated as "OK", and other cases were evaluated as "NG".

<Example 1>

As resin core particles, divinylbenzene-based resin particles were prepared as follows. A fine particle dispersion was obtained by introducing benzoyl peroxide as a polymerization initiator into a solution of divinylbenzene, styrene, and butyl methacrylate in an adjusted mixing ratio, heating the mixture while stirring uniformly at high speed, and conducting a polymerization reaction. A block body, which is an aggregate of fine particles, was obtained by filtering the fine particle dispersion and drying under reduced pressure. Then, divinylbenzene-based resin particles having an average particle diameter of 3.0 µm were obtained by pulverizing the block body. The compressive elastic modulus (20% K value) of these resin core particles when compressed by 20% was 12000 N/mm 2 .

Also, as the insulating particles, alumina (Al ₂ O ₃ ) having an average particle diameter of 150 nm was used. In addition, as the plating solution for the conductive layer, a nickel plating solution containing a nickel plating solution (pH 8.5) containing 0.23 mol/L of nickel sulfate, 0.25 mol/L of dimethylamine borane, and 0.5 mol/L of sodium citrate was used.

First, with respect to 100 parts by mass of an alkali solution containing 5 wt% of a palladium catalyst liquid, a mass part of the resin core particles 10 was dispersed with an ultrasonic disperser, and then the solution was filtered to take out the resin core particles. Then, 10 parts by mass of the resin core particles were added to 100 parts by mass of a 1 wt% solution of dimethylamine borane to activate the surface of the resin core particles. Then, after sufficiently washing the resin core particles with water, 500 parts by mass of distilled water were added and dispersed to obtain a dispersion liquid containing the resin core particles to which palladium adhered.

Next, 1 g of insulating particles was added to the dispersion over 3 minutes to obtain a slurry containing particles with insulating particles. And stirring the slurry at 60 degreeC, the nickel plating liquid was gradually dripped in the slurry, and electroless nickel plating was performed. After confirming that the hydrogen expansion had stopped, the particles were filtered, washed with water, substituted with alcohol, and vacuum dried to obtain conductive particles having protrusions formed of alumina and a conductive layer of Ni-B plating. As a result of observing these conductive particles with a scanning electron microscope (SEM), the average particle diameter was 3 to 4 μm, the number of projections per particle was about 70, and the thickness of the conductive layer was about 100 nm.

As shown in Table 1, a TiO ₂ /Al coated glass substrate and an IC were bonded under compression conditions of 190°C-60 MPa-5 sec using the anisotropic conductive film to which the conductive particles were added, to obtain a bonded structure. The initial resistance value of the bonded structure was 0.6 Ω, the resistance value after the reliability test was 0.9 Ω, the wiring crack generation rate was 0%, and the overall judgment was OK.

<Example 2>

As shown in Table 1, using the same anisotropic conductive film to which conductive particles were added as in Example 1, the TiO ₂ /Al-coated PET substrate and the IC were bonded under compression conditions of 190°C-60 MPa-5 sec, and connected. got a struct. The initial resistance value of the bonded structure was 0.7 Ω, the resistance value after the reliability test was 1.0 Ω, the wiring crack generation rate was 0%, and the overall judgment was OK.

<Example 3>

As the plating solution for the conductive layer, a Ni-W-B plating solution (pH 8.5) containing 0.23 mol/L of nickel sulfate, 0.25 mol/L of dimethylamine borane, 0.5 mol/L of sodium citrate and 0.35 mol/L of sodium tungstate was used. . Except for this, it carried out similarly to Example 1, and obtained the electroconductive particle which has the protrusion formed from alumina, and the electroconductive layer of Ni-W-B plating. As a result of observing these conductive particles with a metal microscope, the average particle diameter was 3 to 4 μm, the number of projections per particle was about 70, and the thickness of the conductive layer was about 100 nm.

As shown in Table 1, a TiO ₂ /Al coated glass substrate and an IC were bonded under compression conditions of 190°C-60 MPa-5 sec using the anisotropic conductive film to which the conductive particles were added, to obtain a bonded structure. The initial resistance value of the bonded structure was 0.3 Ω, the resistance value after the reliability test was 0.5 Ω, the wiring crack incidence rate was 0%, and the overall judgment was OK.

<Example 4>

As shown in Table 1, using the same anisotropic conductive film to which conductive particles were added as in Example 3, the TiO ₂ /Al-coated PET substrate and the IC were bonded under compression conditions of 190°C-60 MPa-5 sec, and connected. got a struct. The initial resistance value of the bonded structure was 0.6 Ω, the resistance value after the reliability test was 0.8 Ω, the wiring crack generation rate was 0%, and the overall judgment was OK.

<Comparative Example 1>

As the insulating particles, silica (SiO ₂ ) having an average particle diameter of 150 nm was used. Except for this, it carried out similarly to Example 1, and obtained the electroconductive particle which has the processus|protrusion formed from silica, and the electroconductive layer of Ni-B plating. As a result of observing these conductive particles with a metal microscope, the average particle diameter was 3 to 4 μm, the number of projections per particle was about 70, and the thickness of the conductive layer was about 100 nm.

As shown in Table 1, a TiO ₂ /Al coated glass substrate and an IC were bonded under compression conditions of 190°C-60 MPa-5 sec using the anisotropic conductive film to which the conductive particles were added, to obtain a bonded structure. The initial resistance value of the bonded structure was 1.5 Ω, the resistance value after the reliability test was 3.0 Ω, the occurrence rate of wiring cracks was 0%, and the overall judgment was NG.

<Comparative Example 2>

As shown in Table 1, using the same anisotropic conductive film to which conductive particles were added as in Comparative Example 1, the TiO ₂ /Al-coated PET substrate and the IC were bonded under compression conditions of 190°C-60 MPa-5 sec, and connected. got a struct. The initial resistance value of the bonded structure was 3.0 Ω, the resistance value after the reliability test was 6.0 Ω, the wiring crack incidence rate was 0%, and the overall judgment was NG.

<Comparative Example 3>

As the insulating particles, silica (SiO ₂ ) having an average particle diameter of 150 nm was used. Further, as a plating solution for the conductive layer, a Ni-WB plating solution (pH 8.5) containing 0.23 mol/L of nickel sulfate, 0.25 mol/L of dimethylamine borane, 0.5 mol/L of sodium citrate and 0.35 mol/L of sodium tungstate was used. used Except for this, it carried out similarly to Example 1, and obtained the electroconductive particle which has the processus|protrusion formed from silica, and the conductive layer of Ni-WB plating. As a result of observing these conductive particles with a scanning electron microscope (SEM), the average particle diameter was 3 to 4 μm, the number of projections per particle was about 70, and the thickness of the conductive layer was about 100 nm.

As shown in Table 1, a TiO ₂ /Al coated glass substrate and an IC were bonded under compression conditions of 190°C-60 MPa-5 sec using the anisotropic conductive film to which the conductive particles were added, to obtain a bonded structure. The initial resistance value of the bonded structure was 0.7 Ω, the resistance value after the reliability test was 1.1 Ω, the wiring crack generation rate was 0%, and the overall judgment was NG.

<Comparative Example 4>

As shown in Table 1, using the same anisotropic conductive film to which conductive particles were added as in Comparative Example 3, the TiO ₂ /Al-coated PET substrate and the IC were bonded under compression conditions of 190°C-60 MPa-5 sec, and connected. got a struct. The initial resistance value of the bonded structure was 1.8 Ω, the resistance value after the reliability test was 3.6 Ω, the wiring crack incidence rate was 0%, and the overall judgment was NG.

<Comparative Example 5>

As shown in Table 1, using the same anisotropic conductive film to which conductive particles were added as in Comparative Example 3, the TiO ₂ /Al-coated PET substrate and the IC were bonded under compression conditions of 190°C-100 MPa-5 sec, and connected. got a struct. The initial resistance value of the bonded structure was 0.7 Ω, the resistance value after the reliability test was 1.0 Ω, the wiring crack incidence rate was 25%, and the overall judgment was NG.

As in Comparative Example 1, when Ni-B was formed as the conductive layer and silica having a Mohs hardness of 7 was used as the insulating particle, the resistance after the reliability test increased. In addition, when PET substrates were connected using the conductive particles of Comparative Example 1 as in Comparative Example 2, the resistance after the reliability test greatly increased. Also, as in Comparative Example 3, when Ni-W-B was formed as the conductive layer and silica having a Mohs hardness of 7 was used as the insulating particle, the resistance after the reliability test increased. Further, when PET substrates were connected using the conductive particles of Comparative Example 2 as in Comparative Example 4, the resistance after the reliability test greatly increased. Further, when the PET substrates were connected by increasing the pressure during crimping as in Comparative Example 5, the increase in resistance after the reliability test could be suppressed, but cracks occurred.

On the other hand, as in Examples 1 to 4, when alumina having a Mohs hardness of 9 is used as the insulating particle, the increase in resistance after the reliability test can be suppressed without increasing the pressure during compression, and the occurrence of cracks can be prevented Could. In addition, as in Examples 2 and 4, low resistance could be realized even in the connection of PET substrates. Further, as in Example 4, by forming Ni-W-B as the conductive layer, further low resistance was realized in the connection of PET substrates. These are considered to be because the contact between the wiring and the conductive particles was increased by piercing the oxide layer on the surface of the wiring without increasing the pressure at the time of crimping, since the hardness of the insulating particles was large.

10 resin core particles
20 insulating particles
30, 31, 32, 33, 34 conductive layer
40 conductive particles
41 resin core particles
42 insulating particles
50 1st circuit member
51 terminal
52 oxide layer

Claims (18)

A plurality of resin core particles, insulating particles attached to the surface of the resin core particles to form protrusions, and a conductive layer disposed on the surfaces of the resin core particles and the insulating particles, wherein the Mohs hardness of the insulating particles is Through a conductive material containing conductive particles having a compressive elastic modulus greater than 7 and having a compressive elastic modulus of 500 to 20000 N/mm when the resin core particles are compressed by 20%,
A method for manufacturing a connection structure in which a terminal of a first circuit member and a terminal of a second circuit member, which are plastic substrates having an elastic modulus of 2000 MPa to 4100 MPa, are crimped together,
The manufacturing method of the connection structure in which an oxide layer is formed on the terminal of the said 1st circuit member. According to claim 1,
The manufacturing method of the bonded structure in which the conductive layer of the said electroconductive particle is nickel or a nickel alloy. According to claim 1 or 2,
The method for producing a bonded structure in which the insulating particles of the conductive particles are at least one of zirconia, alumina, tungsten carbide, and diamond. According to claim 1 or 2,
The average particle diameter of insulating particles of the conductive particles is 100 to 200 nm,
The number of projections formed on the surface of the resin core particles of the conductive particles is 1 to 500,
The manufacturing method of the bonded structure whose thickness of the conductive layer of the said electroconductive particle is 80-150 nm. According to claim 1 or 2,
The manufacturing method of the connection structure formed by pressing from the said 2nd circuit member side. According to claim 1 or 2,
A method for producing a bonded structure comprising crimping a terminal of the first circuit member and a terminal of the second circuit member with a pressure of 10 to 80 MPa. According to claim 1 or 2,
The manufacturing method of the connection structure in which a _TiO2 layer is formed on the terminal of the said 1st circuit member. A plurality of resin core particles, insulating particles attached to the surface of the resin core particles to form protrusions, and a conductive layer disposed on the surfaces of the resin core particles and the insulating particles, wherein the Mohs hardness of the insulating particles is 7 or more, and the compressive elastic modulus when the resin core particles are compressed by 20% is 500 to 20000 N/mm 2 By conductive particles,
A terminal of a first circuit member, which is a plastic substrate having an elastic modulus of 2000 MPa to 4100 MPa, and a terminal of a second circuit member are connected,
The connection structure formed by forming an oxide layer on the terminal of the said 1st circuit member. According to claim 8,
The connection structure in which the conductive layer of the said electroconductive particle is nickel or a nickel alloy. According to claim 8 or 9,
A bonded structure in which the insulating particles of the conductive particles are at least one or more of zirconia, alumina, tungsten carbide, and diamond. According to claim 8 or 9,
The average particle diameter of insulating particles of the conductive particles is 100 to 200 nm,
The number of projections formed on the surface of the resin core particles of the conductive particles is 1 to 500,
The connection structure whose thickness of the conductive layer of the said electroconductive particle is 80-150 nm. According to claim 8 or 9,
A connection structure in which a TiO ₂ layer is formed on the terminal of the first circuit member. A plurality of resin core particles, insulating particles attached to the surface of the resin core particles to form protrusions, and a conductive layer disposed on the surfaces of the resin core particles and the insulating particles, wherein the Mohs hardness of the insulating particles is Containing conductive particles having a compressive modulus greater than 7 and having a compressive elastic modulus of 500 to 20000 N/mm when the resin core particles are compressed by 20%,
As a conductive material for connecting the terminal of the first circuit member and the terminal of the second circuit member, which is a plastic substrate having an elastic modulus of 2000 MPa to 4100 MPa,
The conductive material formed by forming an oxide layer on the terminal of the said 1st circuit member. According to claim 13,
The conductive material in which the conductive layer of the said conductive particle is nickel or a nickel alloy. According to claim 13,
The conductive material in which the insulating particles of the conductive particles are at least one or more of zirconia, alumina, tungsten carbide, and diamond. According to claim 13,
The average particle diameter of insulating particles of the conductive particles is 100 to 200 nm,
The number of projections formed on the surface of the resin core particles of the conductive particles is 1 to 500,
The electrically-conductive material whose thickness of the conductive layer of the said electroconductive particle is 80-150 nm. According to claim 13,
A conductive material comprising a TiO ₂ layer formed on a terminal of the first circuit member. A conductive film in which the conductive material according to any one of claims 13 to 17 is formed in a film form.

Images