HK1192654A

HK1192654A - Anisotropic conductive film, process for producing anisotropic conductive film, connecting method, and bonded object

Info

Publication number: HK1192654A
Application number: HK14105877.1A
Authority: HK
Inventors: 石松朋之
Original assignee: 迪睿合电子材料有限公司
Priority date: 2011-08-23
Filing date: 2012-08-08
Publication date: 2014-08-22

Description

Anisotropic conductive film, method for producing anisotropic conductive film, connection method, and joined body

Technical Field

The present invention relates to an anisotropic conductive film that can electrically and mechanically connect electronic components such as an IC chip and a liquid crystal panel (LCD panel) in a Liquid Crystal Display (LCD), a method for producing the anisotropic conductive film, a connecting method using the anisotropic conductive film, and a joined body.

Background

Conventionally, as a means for connecting an electronic component and a substrate, a tape-shaped connecting material (for example, Anisotropic Conductive Film (ACF)) in which a thermosetting resin in which Conductive particles are dispersed is applied to a release Film has been used.

The anisotropic conductive film is mainly used when terminals of a Flexible Printed Circuit (FPC) and an IC chip are connected to ito (indium Tin oxide) electrodes formed on a glass substrate of an LCD panel, for example, and is used when various terminals are bonded to each other and electrically connected to each other.

In recent years, electronic components are being further miniaturized and integrated. Therefore, the pitch between adjacent electrodes of the above-described electronic component becomes smaller (fine pitch). However, the conductive component used for the anisotropic conductive film is generally spherical, and the size thereof is often a diameter of several μm or more. When electrodes with a small inter-electrode pitch, which are miniaturized and integrated, are connected using such an anisotropic conductive film, there is a problem that the insulation resistance between adjacent electrodes (terminals) is insufficient. Therefore, in anisotropic conductive connection with a fine pitch, it is required to obtain excellent on-resistance and insulation resistance between adjacent terminals.

Therefore, as a technique related to fine pitches, an anisotropic conductive material in which metal powder having a shape in which fine metal particles are chain-connected is dispersed in a rubber material has been proposed as an anisotropic conductive material that can be used for connection between substrates and an inductive sensor (see patent document 1).

However, in the technique proposed in this proposal, there is a problem that metal powders come into contact with each other at the time of anisotropic conductive connection, insulation resistance between adjacent electrodes in the substrate or the electronic component cannot be sufficiently secured, and short circuit occurs. Further, since the number of the metal particles to be connected is not specified, there is a problem that the metal particles which do not effectively act on the anisotropic conductive connection exist in the chain, and the particle capture rate is lowered.

Further, as a connecting method using an anisotropic conductive member, a connecting method including a step of sandwiching an anisotropic conductive member including conductive particles containing a magnetic material between two substrates on which conductor patterns to be connected are formed, a step of applying a magnetic field so as to control an orientation state of the conductive particles, and a step of hot press-fitting the 2 substrates has been proposed (see patent document 2).

However, in the technique proposed in this proposal, since a magnetic field is applied when anisotropic conductive connection is performed, a plurality of conductive particles are linked in a chain form by the applied magnetic field, and as a result, insulation resistance between adjacent electrodes in a substrate or an electronic component cannot be sufficiently ensured, and a short circuit occurs. Further, if a plurality of conductive particles are linked in a chain, there is a problem that conductive particles that do not effectively act on anisotropic conductive connection exist in the chain, and the particle capture rate is lowered.

Therefore, in the anisotropic conductive connection with a fine pitch, it is currently required to provide an anisotropic conductive film which can obtain insulation resistance between adjacent terminals and can perform anisotropic conductive connection with excellent on-resistance and particle capture rate, a method for producing the anisotropic conductive film, a connection method using the anisotropic conductive film, and a bonded body.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2003-346556

Patent document 2: japanese laid-open patent publication No. 2004-185857

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above problems and to achieve the following object. That is, an object of the present invention is to provide an anisotropic conductive film which can obtain insulation resistance between adjacent terminals in anisotropic conductive connection with a fine pitch and can perform anisotropic conductive connection with excellent on-resistance and particle trapping rate, a method for producing the anisotropic conductive film, a connecting method using the anisotropic conductive film, and a joined body.

Means for solving the problems

The means for solving the above problems are as follows. Namely:

< 1 > an anisotropic conductive film for anisotropically and electrically connecting a terminal of a substrate and a terminal of an electronic component,

contains a conductive particle and a conductive metal oxide,

the conductive particles are at least one of conductive particles in which a metal plating layer and an insulating layer are provided on the surface of resin particles in this order and conductive particles in which an insulating layer is provided on the surface of metal particles,

the conductive particles are connected by 3.0 to 10.0 on average.

< 2 > the anisotropic conductive film according to the above < 1 >, wherein the metal plating layer is a magnetic metal plating layer containing at least one of Fe, Ni, and Co.

< 3 > the anisotropic conductive film according to the above < 1 >, wherein the metal particles are nickel particles.

< 4 > the anisotropic conductive film according to any one of the above < 1 > -to < 3 >, wherein the particle connection ratio of the conductive particles is 8% to 50%.

[ 5 ] A method for manufacturing an anisotropic conductive film, which is any one of the methods < 1 > to < 4 >, comprising:

a magnetization step of magnetizing conductive particles of an anisotropic conductive composition containing the conductive particles having magnetism; and

and a coating step of coating the anisotropic conductive composition containing the magnetized conductive particles on a substrate.

< 6 > a connecting method for anisotropically and electrically connecting a terminal of a substrate and a terminal of an electronic component, comprising:

a bonding step of bonding an anisotropic conductive film to the terminals of the substrate,

A step of mounting an electronic component on the anisotropic conductive film,

A heating and extruding step of heating and extruding the electronic component by a heating and extruding member,

the anisotropic conductive film according to any one of claims < 1 > -4.

< 7 > the joined body, which is produced by the joining method < 6 > described above.

Effects of the invention

The present invention can solve the above-described problems of the related art, and can achieve the above-described object, and can provide an anisotropic conductive film which can obtain insulation resistance between adjacent terminals in anisotropic conductive connection with a fine pitch and can perform anisotropic conductive connection with excellent on-resistance and particle trapping rate, a method for producing the anisotropic conductive film, a connection method using the anisotropic conductive film, and a bonded body.

Drawings

FIG. 1 is a schematic cross-sectional view showing an example of the anisotropic conductive film of the present invention.

Detailed Description

(Anisotropic conductive film)

The anisotropic conductive film of the present invention is an anisotropic conductive film for anisotropically and electrically connecting a terminal of a substrate and a terminal of an electronic component, and contains conductive particles and further contains other components as necessary.

< conductive particle >

The conductive particles are at least one of conductive particles in which a metal plating layer and an insulating layer are provided on the surface of resin particles in this order, and conductive particles in which an insulating layer is provided on the surface of metal particles.

The shape and size of the conductive particles are not particularly limited and may be appropriately selected according to the purpose.

Resin particles-

The material of the resin particles is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include: polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyisobutylene, polybutadiene, polyalkylene terephthalate, polysulfone, polycarbonate, polyamide, phenol resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, (meth) acrylate polymer, divinylbenzene-based copolymer, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

Among them, preferred are (meth) acrylate polymers, divinylbenzene polymers and divinylbenzene-based copolymers.

Examples of the divinylbenzene-based copolymer include a divinylbenzene-styrene copolymer and a divinylbenzene- (meth) acrylate copolymer.

Here, the (meth) acrylate refers to either methacrylate or acrylate. The (meth) acrylate polymer may be either a crosslinked type or a non-crosslinked type, if necessary, or may be used in combination.

The shape of the resin particles is not particularly limited and may be appropriately selected depending on the purpose, but it is preferable that the surface shape has fine irregularities.

The structure of the resin particles is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a single-layer structure and a laminated structure.

The average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1 to 50 μm, more preferably 2 to 20 μm, and particularly preferably 2 to 10 μm.

When the average particle diameter of the resin particles is less than 1 μm or more than 50 μm, a sharp particle size distribution may not be obtained. On the other hand, when the average particle diameter of the resin particles is within the above-described particularly preferable range, it is advantageous in that good connection reliability is obtained.

The average particle diameter of the resin particles can be measured, for example, using a particle size distribution measuring apparatus (product name: マイクロトラック MT3100, manufactured by Nikkiso Co., Ltd.).

Metal plating layer-

The metal plating layer is not particularly limited as long as it is a plating layer formed on the surface of the resin particle, and may be appropriately selected depending on the purpose, but a magnetic metal plating layer containing at least one of Fe, Ni, and Co is preferable, and a magnetic metal plating layer containing Ni is more preferable, from the viewpoint of enhancing the magnetic properties and increasing the particle connection rate.

The metal plating layer may contain at least one of phosphorus and boron.

The phosphorus concentration in the metal plating layer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10% by mass or less, and more preferably 3.0% by mass to 10% by mass. When the phosphorus concentration exceeds 10 mass%, the particle connection rate, the number of particles captured, and the particle capture rate (particle capture efficiency) may decrease.

The boron concentration in the metal plating layer is not particularly limited and may be appropriately selected according to the purpose.

The method of adjusting the phosphorus concentration and the boron concentration of the metal plating layer is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include a method of controlling the pH of the plating reaction, a method of controlling the phosphoric acid concentration and the boron concentration in the plating solution, and the like.

Among them, a method of controlling the pH of the plating reaction is preferable from the viewpoint of excellent reaction control.

The phosphorus concentration and the boron concentration in the metal plating layer can be measured by analyzing the composition of the plating layer using EDX (energy dispersive X-ray analysis apparatus, product of hitachi ハイテクノロジーズ), for example.

Examples of the plating include Ni — P (nickel-phosphorus) plating, Ni-B (nickel-boron) plating, Fe plating, and Co plating.

The average thickness of the metal plating layer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10nm to 200 nm.

When the average thickness exceeds 200nm, the particles after plating are likely to aggregate together by plating, and may be easily formed into large particles.

The average thickness of the metal plating layer is obtained by grinding a cross section of 10 particles selected arbitrarily using, for example, a focused ion beam machining and observation apparatus (manufactured by Hitachi ハイテクノロジー, trade name: FB-2100), measuring the thickness of the metal plating layer using a transmission electron microscope (manufactured by Hitachi ハイテクノロジー, trade name: H-9500), and arithmetically averaging the measured values.

The plating method for forming the metal plating layer is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include an electroless plating method and a sputtering method.

Metal particles-

The metal particles are not particularly limited and may be appropriately selected according to the purpose, and examples thereof include: copper, iron, nickel, gold, silver, aluminum, zinc, stainless steel, hematite (Fe)₂O₃) Magnetite (Fe)₃O₄) The general formula is as follows: MFe₂O₄、MO·nFe₂O₃(in the two formulae, M represents 2 metal, for example, can be cited Mn, Co, Ni, Cu, Zn, Ba, Mg, N is a positive integer, and, the M in the repetition can be the same or different types.) expressed by various ferrite, silicon steel powder, permalloy, Co based amorphous alloy, Shandast alloy, Alpamm high permeability iron aluminum alloy, nickel iron molybdenum high permeability alloy, Bowman alloy, Bonwawa constant permeability alloy various metal powder, its alloy powder. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, nickel particles are more preferable from the viewpoint of connection reliability.

Insulating layer-

The insulating layer is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a layer made of a resin. The resin is not particularly limited and may be suitably selected according to the purpose, and examples thereof include a solid epoxy resin, a phenoxy resin, a vinyl polymer, a polyester resin, an alkylated cellulose resin, and a flux (フラックス) resin.

The method of coating the insulating layer on the resin particles and the metal particles provided with the metal plating layer is not particularly limited and may be appropriately selected depending on the purpose, and for example, a method of dispersing the resin particles or the metal particles provided with the metal plating layer in a resin solution, heating the resulting dispersion as fine droplets while spraying, and drying the solvent may be mentioned. The resin used in this method is not particularly limited and may be suitably selected according to the purpose, and examples thereof include a solid epoxy resin, a phenoxy resin, a vinyl polymer, a polyester resin, an alkylated cellulose resin, and a flux resin.

The average particle diameter of the conductive particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1 to 50 μm, and more preferably 2 to 10 μm. When the average particle diameter is less than 1 μm, the function as conductive particles may not be found, leading to conduction failure, and when it exceeds 50 μm, the film forming ability may be lowered, causing defects in production.

The average particle diameter of the conductive particles can be measured, for example, using a particle size distribution measuring apparatus (product name: マイクロトラック MT3100, manufactured by Nikkiso Co., Ltd.).

The conductive particles are connected to the anisotropic conductive film by an average number of 3.0 to 10.0, preferably an average number of 3.0 to 5.0. If the average number of the bonds is less than 3.0, the particle capturing rate decreases, and if it exceeds 10.0, the pressing force during press-fitting becomes poor, resulting in poor conduction.

The connection of the conductive particles means a state in which the conductive particles are in contact with each other. The method of connecting the conductive particles is not particularly limited and may be appropriately selected depending on the purpose, but the magnetization step in the method for producing an anisotropic conductive film of the present invention to be described later is preferable.

The average number of connections can be determined by the following method. The anisotropic conductive film was observed with a metal microscope (trade name: MX51, manufactured by Olympus corporation), the number of connected particles of 1,000 conductive particles observed was counted, and [ 1,000/(the number of connected particles) ] was defined as the average number of connections.

Here, the anisotropic conductive film will be described with reference to fig. 1, in which the conductive particles are connected to each other. FIG. 1 is a schematic sectional view of an example of the anisotropic conductive film of the present invention. The anisotropic conductive film 1 contains conductive particles 2 and a resin layer 3 containing a film-forming resin or the like. In fig. 1, the number of connected conductive particles in the group a in which 4 conductive particles are in continuous contact with beads is 4. The number of the connected conductive particles of the group B of 4 conductive particles in aggregated contact is 4. The 9 conductive particles are partially connected by a plurality of beads, and the number of the conductive particles connected in the particle group C in which a portion is in aggregated contact is 9. As a connection method, a particle group in which conductive particles are aggregated and contacted is preferable in terms of increasing a particle capture rate.

The particle connection ratio of the conductive particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 8% to 80%, more preferably 8% to 50%, and particularly preferably 30% to 50%. When the particle connection ratio is less than 8%, the improvement of the particle capturing ratio may be insufficient, and when it exceeds 80%, the particle capturing ratio may be lowered, and conductive particles which cannot be captured may be easily present.

Here, the particle connection rate (%) is for each 1mm²Number of conductive particles [ particle density (A) (number/mm) of anisotropic conductive film²) Density (B) (number/mm) of particles connected to 2 or less particles²) (conductive particles not connected with other conductive particles, and conductive particles with a number of conductive particles connected of 2 particles of anisotropic conductiveFilm per 1mm²The number of (2) was counted and obtained from the following formula (1). The particle density (surface density) can be measured, for example, by using a metal microscope (trade name: MX51, manufactured by Olympus corporation).

Particle connection rate (%) [ 1- (particle density (B)/particle density (a) of particles connected to 2 or less) ] × 100 formula (1)

In the formula (1), the number of conductive particles in the case where 2 conductive particles are connected is counted as 2 conductive particles.

The content of the conductive particles in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

< other ingredients >

The other components are not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a film-forming resin, a thermosetting resin, a curing agent, and a silane coupling agent.

Film-forming resin-

The film-forming resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include: phenoxy resin, unsaturated polyester resin, saturated polyester resin, polyurethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, and the like. The film-forming resin may be used alone in 1 kind, or may be used in combination in 2 or more kinds. Among them, phenoxy resins are particularly preferable from the viewpoint of film-forming properties, processability, and connection reliability.

The phenoxy resin is a resin synthesized from bisphenol a and epichlorohydrin, and any resin that is suitable for synthesis or a commercially available product may be used.

The content of the film-forming resin in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

Thermosetting resins

The thermosetting resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include epoxy resins, acrylic resins, and the like.

-epoxy resins-

The epoxy resin is not particularly limited and may be suitably selected according to the purpose, and examples thereof include thermosetting epoxy resins such as bisphenol a type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, and modified epoxy resins thereof. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The content of the epoxy resin in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

-acrylic resin- -

The acrylic resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include: methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, phosphate group-containing acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1, 3-diacryloyloxypropane, 2-bis [4- (acryloyloxymethyl) phenyl ] propane, 2-bis [4- (acryloyloxyethoxy) phenyl ] propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, tris (acryloyloxyethyl) isocyanurate, urethane acrylate, epoxy acrylate, and the like. In addition, those obtained by replacing the above-mentioned acrylate with methacrylate may also be used. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The content of the acrylic resin in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

Curing agents

The curing agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a cationic curing agent, an anionic curing agent, and a radical curing agent.

- -cationic curing agent- -

The cationic curing agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include sulfonium salts, phosphonium salts, and the like,Salts and the like. Among them, aromatic sulfonium salts are preferred.

The cationic curing agent is preferably used in combination with an epoxy resin as the thermosetting resin.

The content of the cationic curing agent in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

An anionic curing agent- -

The anionic curing agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include polyamine and the like.

The anionic curing agent is preferably used in combination with an epoxy resin as the thermosetting resin.

The content of the anionic curing agent in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

A radical curing agent- -

The radical curing agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include organic peroxides.

The radical curing agent is preferably used in combination with an acrylic resin as the thermosetting resin.

The content of the radical curing agent in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

Silane coupling agents

The silane coupling agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include epoxy silane coupling agents, acrylic silane coupling agents, thiol silane coupling agents, and amine silane coupling agents.

The content of the silane coupling agent in the anisotropic conductive film is not particularly limited and may be appropriately selected according to the purpose.

The thickness of the anisotropic conductive film is not particularly limited and can be appropriately selected according to the purpose.

(method for producing Anisotropic conductive film)

The method for producing an anisotropic conductive film according to the present invention is the method for producing an anisotropic conductive film according to the present invention, and includes at least a magnetization step and a coating step, and further includes other steps as necessary.

< magnetizing Process >

The magnetizing step is not particularly limited as long as it is a step of magnetizing the conductive particles of the anisotropic conductive composition containing the conductive particles having magnetism, and may be appropriately selected according to the purpose.

The conductive particles are the conductive particles in the anisotropic conductive film of the present invention.

The anisotropic conductive composition is not particularly limited as long as it contains the conductive particles, and can be appropriately selected according to the purpose, and for example, it contains at least the conductive particles, and more preferably contains a film-forming resin, a thermosetting composition, a curing agent, and the like.

The film-forming resin in the anisotropic conductive composition is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include the film-forming resins exemplified in the description of the anisotropic conductive film of the present invention.

The thermosetting resin in the anisotropic conductive composition is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include the thermosetting resins exemplified in the description of the anisotropic conductive film of the present invention.

The curing agent in the anisotropic conductive composition is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include the curing agents exemplified in the description of the anisotropic conductive film of the present invention.

The method of magnetizing the conductive particles is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include a method of magnetizing by using a pulse magnetizing apparatus.

The condition for the magnetization is not particularly limited as long as the conductive particles are in a state of being linked by 3.0 to 10.0 particles on average in the obtained anisotropic conductive film, and can be appropriately selected according to the purpose.

< coating Process >

The coating step is not particularly limited as long as the step is a step of coating an anisotropic conductive composition containing the magnetized conductive particles on a substrate, and may be appropriately selected according to the purpose.

The material of the substrate is not particularly limited and may be appropriately selected depending on the purpose, but a polyethylene terephthalate film is preferable. For the purpose of improving the strength, the polyethylene terephthalate film may contain an inorganic filler such as titanium oxide.

The average thickness of the base material is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10 to 80 μm, and more preferably 12 to 75 μm.

When the average thickness of the substrate is less than 10 μm, handling of the anisotropic conductive film during mounting may be difficult due to a decrease in tensile strength, etc., and when it exceeds 80 μm, it may be difficult to form a roll shape, and the amount of waste may increase because the final substrate is discarded.

If necessary, the base material may be subjected to a mold release treatment such as a silicone treatment.

The coating method is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include: various coating methods typified by a blade coating method, a spray coating method, a spin coating method, a roll coating method, and the like, a hot melt method, a coextrusion method, and the like.

In the coating, heating may be performed as necessary. The heating temperature and the heating time are not particularly limited and may be appropriately selected depending on the purpose.

(connection method and bonded body)

The connecting method of the present invention includes at least a bonding step, a mounting step, a heating and pressing step, and further includes other steps as necessary.

The connection method is a connection method for anisotropically and electrically connecting the terminals of the substrate and the terminals of the electronic component.

The joined body of the present invention is produced by the above joining method of the present invention.

< substrate >

The substrate is not particularly limited as long as it is a substrate having a terminal to be subjected to anisotropic conductive connection, and may be appropriately selected according to the purpose, and examples thereof include an ITO glass substrate, a flexible substrate, and a rigid substrate.

The size, shape, and structure of the substrate are not particularly limited, and may be appropriately selected according to the purpose.

< electronic part >

The electronic component is not particularly limited as long as it is an electronic component having a terminal to be subjected to anisotropic conductive connection, and can be appropriately selected according to the purpose, and examples thereof include an IC chip, a TAB tape, a liquid crystal panel, and the like. Examples of the IC chip include an IC chip for controlling a liquid crystal screen of a Flat Panel Display (FPD).

< bonding Process >

The bonding step is not particularly limited as long as it is a step of bonding an anisotropic conductive film to the terminal of the substrate, and may be appropriately selected according to the purpose.

The anisotropic conductive film is the anisotropic conductive film of the present invention.

< mounting step >

The mounting step is not particularly limited as long as the electronic component is mounted on the anisotropic conductive film, and may be appropriately selected according to the purpose.

Usually, no anisotropic conductive connection is made at this time.

< Process of heating and extruding >

The heating and pressing step is not particularly limited as long as it is a step of heating and pressing the electronic component by a heating and pressing member, and may be appropriately selected according to the purpose.

Examples of the heating and pressing member include a pressing member having a heating mechanism. As the pressing member having the heating mechanism, for example, a hot tool or the like can be cited.

The heating temperature is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include 100 to 250 ℃.

The pressure for the extrusion is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include 0.1 to 100 MPa.

The time for the heating and pressing is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include 0.5 to 120 seconds.

In the heating and pressing step, the anisotropic conductive film is preferably softened and then cured.

In the heating and pressing step, the conductive particles present between the terminals of the substrate and the terminals of the electronic component are deformed by the pressure acting between the terminals by heating and pressing. Due to this deformation, the insulating layer of the conductive particles is broken, and the metal plating layer or the metal particles of the conductive particles are exposed. Since the metal plating layer or the metal particles of the conductive particles are exposed, the terminals of the substrate and the terminals of the electronic component can be electrically connected via the conductive particles, and anisotropic conductive connection can be performed.

In this case, the conductive particles are connected by 3.0 to 10.0 particles on average, so that the particle capturing ratio is improved and excellent anisotropic conductive connection is realized.

Further, even when the anisotropic conductive film is heated and pressed, the conductive particles present between the terminals of the substrate or between the terminals of the electronic component are hardly deformed. Therefore, the metal plating layer or the metal particles of the conductive particles present between the terminals of the substrate or between the terminals of the electronic component are not exposed, but are always covered with the insulating layer. Accordingly, even when the conductive particles are connected to each other and span between the terminals of the substrate or between the terminals of the electronic component, the insulation resistance between the terminals of the substrate or between the terminals of the electronic component can be maintained, and as a result, a short circuit can be prevented.

[ examples ] A method for producing a compound

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, parts indicate parts by mass.

Production example 1

< preparation of crosslinked polystyrene particles >

Benzoyl peroxide is added as a polymerization initiator to a solution in which the mixing ratio of divinylbenzene, styrene and butyl methacrylate is adjusted, and polymerization is carried out by heating while uniformly stirring at a high speed, thereby obtaining a fine particle dispersion. The fine particle dispersion is filtered and dried under reduced pressure to obtain a cake (ブロック) as an aggregate of fine particles. The block was further pulverized to obtain crosslinked polystyrene particles having an average particle diameter of 3 μm.

Comparative example 1

< production of Anisotropic conductive film >

Preparation of an anisotropic conductive composition

The crosslinked polystyrene particles having an average particle diameter of 3 μm obtained in production example 1 were sequentially subjected to Ni plating and Au plating in 50 parts of a microcapsule-type amine-based curing agent (product name: ノバキュア HX3941HP, manufactured by Asahi Kasei ケミカルズ Co., Ltd.), 14 parts of a liquid epoxy resin (product name: EP828, manufactured by ジャパンエポキシレジン Co., Ltd.), 35 parts of a phenoxy resin (product name: YP50, manufactured by Nippon Tekko chemical Co., Ltd.) and 1 part of a silane coupling agent (product name: KBE403, manufactured by shin Shich chemical Co., Ltd.) to obtain conductive particles having an average particle diameter of 3 μm, and the conductive particles having a particle density of 4,000 pcs/mm²The above-mentioned components are dispersed therein to obtain an anisotropic conductive composition 1.

The average thickness of the plating layer of the total of the Ni plating and the Au plating was 100 nm.

The average thickness of the plating layer was obtained by grinding a cross section of 10 particles selected arbitrarily using a focused ion beam machining observation apparatus (manufactured by Hitachi ハイテクノロジー, trade name: FB-2100), measuring the thickness of the plating layer using a transmission electron microscope (manufactured by Hitachi ハイテクノロジー, trade name: H-9500), and arithmetically averaging the measured values.

-a magnetizing procedure-

The conductive particles in the anisotropic conductive composition 1 were magnetized by passing a magnetizing current of 1,000A at intervals of 1 time for 3 seconds for 15 seconds using a cylindrical pulse magnetizing apparatus (manufactured by P-2804, マグネットラボ).

Production of anisotropic conductive film

The anisotropic conductive composition 1 containing the magnetized conductive particles was applied to a silicone-treated release PET (polyethylene terephthalate) film so that the average thickness after drying was 20 μm, to obtain a sheet-like anisotropic conductive film 1.

< method of joining (production of joined body) >

As evaluation substrates, anisotropic conductive connection was performed using COF (evaluation substrate, 35 μm pitch, line/space 1/1, Cu8 μm thickness-Sn-plated, 38 μm thickness-S' perflex substrate) and ITO coated glass (evaluation substrate, 35 μm pitch, glass thickness 0.7 mm).

Specifically, the anisotropic conductive film 1 thus produced was cut into a width of 1.0 mm. The anisotropic conductive film 1 was bonded to ITO-coated glass.

After the COF was placed thereon and pre-fixed in place, anisotropic conductive connection was performed at 190 ℃ under press-fitting conditions, 3MPa, and 10 seconds (tool speed 10 mm/sec, step temperature 40 ℃) using a thermal tool having a width of 1.0mm and using a buffer material (テフロン (registered trademark) having a thickness of 70 μm), thereby producing a bonded body 1.

< evaluation >

The following evaluations were performed on the produced anisotropic conductive film and the joined body. The results are shown in Table 1-1.

[ average number of links ]

The average number of the connected conductive particles in the anisotropic conductive film was determined by observing the anisotropic conductive film using a metal microscope (product name: MX51, manufactured by olympus corporation), counting the number of connected particle groups of 1,000 conductive particles observed, and taking [ 1,000 pieces/(number of connected particle groups) ] as the average number of the connections.

[ particle connection Rate ]

Particle connection (%) by counting per 1mm²Number of conductive particles [ particle density (A) (number/mm) of anisotropic conductive film²) Density (B) (number/mm) of particles connected to 2 or less particles²) (conductive particles not connected with other conductive particles and conductive particles of the number of 2 particles connected anisotropic conductive film per 1mm²The number of (d) and is obtained according to the following formula (1).

In the formula (1), the number of conductive particles is 2 when the conductive particles are connected.

[ number of particle traps and particle trapping rate (particle trapping efficiency) ]

The number of particles captured and the particle capture rate (particle capture efficiency) were measured by the following methods.

The number of conductive particles (the number of particles after bonding) at 100 terminals of each bonded body was counted by a metal microscope (product name: MX51, manufactured by Olympus corporation).

The maximum value and the minimum value of the number of particles per terminal at this time, or even the average value, are determined as the number of captured particles.

Further, the particle capture rate (particle capture efficiency) per terminal was obtained from the following equation (2).

The particle capturing efficiency (%)

[ (number of particles caught by terminal after press-fitting)/(number of particles existing under terminal before press-fitting) ] × 100 formula (2)

Here, the number of particles captured by the terminal after press-fitting is the number of conductive particles that are present on the terminal and clearly determined to be related to conduction. The term "the number of particles existing under the terminal before press-fitting" means the number of conductive particles existing in the same area as the terminal in the anisotropic conductive film before press-fitting.

[ conduction resistance ]

For each joined body, 1mA current was passed by the 4-terminal method, and the resistance value (. omega.) between the terminals at 15 points was measured. The maximum value, minimum value, and average value at this time were obtained.

[ short circuit occurrence number ]

For each joined body, the insulation resistance value was measured when a voltage of 30V was applied between the terminals. At this time, the insulation resistance value is less than 1 × 10⁸The case of Ω is determined as a short circuit. Then, the number of short-circuit occurrences was determined by measuring the distance between the terminals at 30 points.

Comparative example 2

< production of Anisotropic conductive film and bonded body >

A sheet-like anisotropic conductive film 2 was obtained in the same manner as in comparative example 1, except that Ni plating and Au plating were replaced with Ni — P (nickel-phosphorus) plating described below in comparative example 1.

In addition, the joined body 2 was produced in the same manner as in comparative example 1.

Ni-P-plating

10g of the crosslinked polystyrene particles having an average particle diameter of 3 μm obtained in production example 1 were subjected to alkali etching with a 5 mass% aqueous solution of sodium hydroxide, acid neutralization, and sensitization with a tin dichloride solution. After that, an electroless plating pretreatment comprising an activation treatment of a palladium dichloride solution was performed, and after filtration, conductive particles having palladium adhered to the particle surfaces were obtained.

The obtained conductive particles were diluted with 1,500mL of water, 0.005mmol of bismuth nitrate and 0.006mmol of thallium nitrate were added as plating stabilizers, and the pH was adjusted to 5.7 with 10 mass% sulfuric acid water and 2N aqueous sodium hydroxide solution to prepare a slurry, and the temperature of the slurry was adjusted to 26 ℃.

To this slurry were added 40mL of a mixture of 450g/L nickel sulfate, 80mL of 150g/L sodium hypophosphite and 116g/L sodium citrate, 280mL of water, 0.02mmol of bismuth nitrate and 0.024mmol of thallium nitrate as plating stabilizers, and the pH was adjusted to 9.3 with 28 mass% aqueous ammonia, and the plating solution for the previous stage reaction was added by a metering pump at an addition rate of 80 mL/min.

Thereafter, the mixture was stirred until the pH became stable, and the hydrogen bubbling was confirmed to stop, thereby conducting the preliminary step of electroless plating.

Next, 180mL of a mixed solution of nickel sulfate (450 g/L), sodium hypophosphite (440 mL) (150 g/L) and sodium citrate (116 g/L), and a late-stage reaction plating solution containing 0.3mmol of bismuth nitrate and 0.36mmol of thallium nitrate as a plating stabilizer were added by a quantitative pump at a rate of 27 mL/min.

After that, the mixture was stirred until the pH became stable, and it was confirmed that hydrogen was not foamed, and the subsequent step of electroless plating was carried out.

Next, the plating solution was filtered, and the filtrate was washed with water and then dried in a vacuum dryer at 80 ℃.

The same evaluation as in comparative example 1 was conducted. The results are shown in Table 1-1.

The average thickness of the plating layer was 100nm, and the P (phosphorus) concentration in the plating layer of the conductive particles was 9.5 mass%.

The P concentration and the B (boron) concentration described later were measured by cutting out a cross section of the plated particles using a focused ion beam (manufactured by hitachi ハイテクノロジーズ), and analyzing the composition of the plated layer using EDX (energy dispersive X-ray analysis apparatus, manufactured by hitachi ハイテクノロジーズ).

(example 1)

< production of Anisotropic conductive film and bonded body >

Production of conductive particles 1

Resin particles provided with a metal plating layer were obtained in the same manner as in comparative example 2, except that the P concentration of Ni — P (nickel-phosphorus) plating in comparative example 2 was changed to the P concentration shown in table 1-1.

Then, the insulating layer is coated by the method described in paragraphs [ 0013 ] to [ 0014 ] of Japanese patent laid-open No. 4-362104. The resin particles having the insulating layer coated with the metal plating layer can be confirmed by observing the resin particles with a metal microscope.

Production of anisotropic conductive film and bonded body

An anisotropic conductive film 3 and a joined body 3 were obtained in the same manner as in comparative example 1, except that the conductive particles in comparative example 1 were replaced with the conductive particles 1.

The obtained anisotropic conductive film 3 and the bonded body 3 were evaluated in the same manner as in comparative example 1. The results are shown in Table 1-1.

(examples 2 and 3)

< production of Anisotropic conductive film and bonded body >

Anisotropic conductive films 4 to 5 and bonded bodies 4 to 5 were obtained in the same manner as in example 1, except that the P concentration of Ni-P plating in the production of conductive particles in example 1 was changed to the P concentration shown in Table 1-1.

The average thickness of the plating layer was 100 nm. The resin particles having the metal plating layer covering the insulating layer can be confirmed by observing the resin particles with a metal microscope.

The obtained anisotropic conductive films 4 to 5 and bonded bodies 4 to 5 were evaluated in the same manner as in comparative example 1. The results are shown in Table 1-1.

(example 4)

< production of Anisotropic conductive film and bonded body >

An anisotropic conductive film 6 and a joined body 6 were obtained in the same manner as in example 1, except that Ni — P plating was replaced by Ni — B (nickel-boron) plating in the production of conductive particles in example 1, and the B (boron) concentration in the plating layer was set to 5.5 mass%.

Further, the average thickness of the plating layer was 100 nm. The resin particles having the metal plating layer covering the insulating layer can be confirmed by observing the resin particles with a metal microscope.

The obtained anisotropic conductive film 6 and the bonded body 6 were evaluated in the same manner as in comparative example 1. The results are shown in tables 1 to 2.

(example 5)

< production of Anisotropic conductive film and bonded body >

An anisotropic conductive film 7 and a joined body 7 were obtained in the same manner as in example 1, except that Ni — P plating was replaced by Co plating in the production of conductive particles in example 1.

The obtained anisotropic conductive film 7 and the bonded body 7 were evaluated in the same manner as in comparative example 1. The results are shown in tables 1 to 2.

(example 6)

< production of Anisotropic conductive film and bonded body >

An anisotropic conductive film 8 and a joined body 8 were obtained in the same manner as in example 1, except that the resin particles provided with the metal plating layer in example 1 were replaced by nickel particles (product name: T123, average particle diameter 3 μm, manufactured by インコ Co.).

The insulating layer-coated nickel particles were confirmed by metal microscope observation.

The obtained anisotropic conductive film 8 and the bonded body 8 were evaluated in the same manner as in comparative example 1. The results are shown in tables 1 to 2.

Comparative examples 3 and 4

< production of Anisotropic conductive film and bonded body >

In example 1, except that the magnetization conditions were adjusted so that the average number of the connections of the conductive particles in the anisotropic conductive film was changed to the average number shown in table 1-2, the anisotropic conductive films 9 to 10 and the bonded bodies 9 to 10 were obtained in the same manner as in example 1.

The obtained anisotropic conductive films 9 to 10 and bonded bodies 9 to 10 were evaluated in the same manner as in comparative example 1. The results are shown in tables 1 to 2.

(example 7)

< production of Anisotropic conductive film and bonded body >

In example 1, an anisotropic conductive film 11 and a joined body 11 were obtained in the same manner as in example 1, except that the magnetization conditions were adjusted so that the average number of the connected conductive particles in the anisotropic conductive film was changed to the average number shown in table 1-2.

The obtained anisotropic conductive film 11 and the bonded body 11 were evaluated in the same manner as in comparative example 1. The results are shown in tables 1 to 2.

[ TABLE 1-1 ]

[ TABLE 1-2 ]

In tables 1-1 and 1-2, the P/B concentration is the phosphorus concentration or boron concentration in the plating layer, and the unit is mass%.

In comparative example 1, since Au plating was performed, the magnetic property was weak and the particle connection rate was low. In addition, since conductive particles without an insulating layer are used, a short circuit occurs. In comparative example 2, since Ni — P plating was performed, although the particle connection rate was good due to the magnetism obtained by Ni, short circuits occurred in many cases due to the use of conductive particles without an insulating layer. That is, when conductive particles without an insulating layer are used, the number of short circuits increases as the particle connection ratio increases.

On the other hand, in examples 1 to 7, the particle trapping rate and the on-resistance were excellent, and no short circuit was observed. In examples 1 to 3, the P concentration of Ni-P plating was varied, and the lower the P concentration, the stronger the magnetic property, and the higher the particle connection ratio.

In examples 1 to 2, 4 to 5 and 7, the particle connection ratio was in an appropriate range, and therefore the particle trapping ratio was more excellent.

In comparative example 3, the average number of the conductive particle connections was less than 3.0, and therefore the particle capture rate (particle capture efficiency) was less than 20%, and was insufficient.

In comparative example 4, since the average number of the connections of the conductive particles exceeded 10.0, the on-resistance increased, conduction failure occurred, and short-circuiting occurred in many cases.

Industrial applicability

The anisotropic conductive film and the connection method of the present invention can obtain the insulation resistance between adjacent terminals and can perform anisotropic conductive connection having excellent on-resistance and particle trapping rate, and therefore, can be suitably used for the production of a joined body by anisotropic conductive connection with a fine pitch.

Description of the symbols

1 Anisotropic conductive film

2 conductive particles

3 resin layer

A particle swarm

B particle group

C particle group

Claims

1. An anisotropic conductive film for anisotropically and electrically connecting a terminal of a substrate and a terminal of an electronic component,

contains a conductive particle and a conductive metal oxide,

the conductive particles are connected by 3.0 to 10.0 on average.

2. The acf of claim 1 wherein,

the metal plating layer is a magnetic metal plating layer containing at least one of Fe, Ni, and Co.

3. The acf of claim 1 wherein,

the metal particles are nickel particles.

4. The ACF of any one of claims 1 to 3,

the particle connection ratio of the conductive particles is 8% to 50%.

5. A method for manufacturing an anisotropic conductive film according to any one of claims 1 to 4, comprising:

6. A connecting method for anisotropically and electrically connecting a terminal of a substrate and a terminal of an electronic component, comprising:

A step of mounting an electronic component on the anisotropic conductive film,

the anisotropic conductive film according to any one of claims 1 to 4.

7. A joined body produced by the joining method according to claim 6.