JP2016072239A - Anisotropic conductive film, and connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive film which allows for both prevention of short circuit across adjacent electrodes and conduction between counter electrodes.SOLUTION: An anisotropic conductive film has a conductive particle containing layer containing particles having a conductive core material, and particles having an insulating coating formed of an energy-beam curing resin composition on the surface of the conductive core material, and thermosetting resin, and an insulating adhesive layer containing thermosetting resin.SELECTED DRAWING: Figure 1C

Description

  The present invention relates to an anisotropic conductive film and a connection method using the anisotropic conductive film.

  Conventionally, as a means for connecting an electronic component to a substrate, a tape-like connection material in which a thermosetting resin in which conductive particles are dispersed is applied to a release film (for example, anisotropic conductive film (ACF)) ) Is used.

  This anisotropic conductive film is used, for example, to connect a flexible printed circuit board (FPC) or IC chip terminal (electrode) to an ITO (Indium Tin Oxide) electrode formed on a glass substrate of an LCD panel. As described above, it is used when various electrodes are bonded and electrically connected.

  In recent years, electronic components have been further miniaturized and integrated. For this reason, in the electrodes of the electronic component, the pitch between adjacent electrodes is becoming smaller (fine pitch). However, the conductive component used for the anisotropic conductive film is often spherical and has a size of several μm or more. When such an anisotropic conductive film is used to connect electrodes having a small inter-electrode pitch that has been miniaturized and integrated, there is a problem that insulation resistance between adjacent electrodes cannot be sufficiently obtained.

Therefore, in the fine pitch connection, a technique for reducing the risk of short-circuiting has been proposed by using conductive particles that are insulation-coated with a resin. Examples of the resin used for the insulating coat include a thermoplastic resin and a thermosetting resin.
By using conductive particles coated with insulation, the risk of short-circuiting can be reduced to some extent, but conductive particles trapped between the opposing electrodes must break the insulation coat and become conductive. The strength of the insulating coat itself is designed to be somewhat weak. Therefore, even if the conductive particles are coated with insulation, there is a problem that when the stress is caused by the thermal contraction of the member in a state of being clogged between the electrodes, the insulation coat is broken and a short circuit occurs. .

  Regarding the insulating coating of conductive particles, a technique using an active energy ray curable resin in addition to the thermoplastic resin and the thermosetting resin has been proposed (see, for example, Patent Documents 1 and 2). However, even these proposed techniques cannot achieve both short-circuit prevention between adjacent electrodes and conduction between opposing electrodes in fine pitch connection.

JP-A-6-96620 Japanese Patent Laid-Open No. 11-306861

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an anisotropic conductive film capable of achieving both short-circuit prevention between adjacent electrodes and conduction between counter electrodes, and a connection method using the anisotropic conductive film.

Means for solving the problems are as follows. That is,
<1> Conductive core material, particles having an insulating film formed from an active energy ray-curable resin composition on the surface of the conductive core material, and a conductive particle-containing layer containing a thermosetting resin;
An insulating adhesive layer containing a thermosetting resin;
It is an anisotropic conductive film characterized by having.
<2> The anisotropic conductive film according to <1>, wherein the average thickness of the conductive particle-containing layer is less than the average thickness of the insulating adhesive layer.
<3> The anisotropic conductive film according to any one of <1> to <2>, wherein the active energy ray-curable resin composition contains a (meth) acrylate resin.
<4> The conductive particle-containing layer contains an anionic curing agent,
The insulating adhesive layer contains an anionic curing agent;
The anisotropic conductive film according to any one of <1> to <3>.
<5> A connection method for connecting the wiring of a wiring board having a substrate that transmits active energy rays and a wiring that does not transmit active energy rays, and a terminal of an electronic component,
A first disposing step of disposing the anisotropic conductive film according to any one of <1> to <4> on the wiring of the wiring substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film so that the terminal of the electronic component is in contact with the anisotropic conductive film;
An active energy ray irradiating step of irradiating the anisotropic conductive film with the active energy ray from the wiring board side;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member.
<6> The second arrangement step includes a temporary fixing process in which the anisotropic conductive film is heated and pressed at a temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and at the curing temperature of −10 ° C. or higher. The connection method according to <5>.

  According to the present invention, the conventional problems can be solved, the object can be achieved, and the anisotropic conductive film capable of achieving both prevention of short-circuit between adjacent electrodes and conduction between counter electrodes, and the different A connection method using an anisotropic conductive film can be provided.

FIG. 1A is a schematic diagram for explaining a first arrangement step in an example of the connection method of the present invention. FIG. 1B is a schematic diagram for explaining a second arrangement step in an example of the connection method of the present invention. FIG. 1C is a schematic diagram for explaining an active energy ray irradiation step in an example of the connection method of the present invention. FIG. 1D is a schematic diagram for explaining a heating and pressing step in an example of the connection method of the present invention.

(Anisotropic conductive film)
The anisotropic conductive film of the present invention has a conductive particle-containing layer and an insulating adhesive layer, and further contains other components as necessary.

<Conductive particle-containing layer>
The conductive particle-containing layer contains at least particles and a thermosetting resin, preferably contains a curing agent, and further contains other components as necessary.

<< Particles >>
The particles include a conductive core material and an insulating film, and further include other components as necessary.
In the particles, the insulating film is formed on the surface of the conductive core material.

-Conductive core material-
There is no restriction | limiting in particular as said electroconductive core material, According to the objective, it can select suitably, For example, a metal particle, a metal covering resin particle, etc. are mentioned.

There is no restriction | limiting in particular as said metal particle, According to the objective, it can select suitably, For example, nickel, cobalt, silver, copper, gold | metal | money, palladium etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, nickel, silver, and copper are preferable. These metal particles may be provided with gold or palladium on the surface for the purpose of preventing surface oxidation.

The metal-coated resin particles are not particularly limited as long as the surfaces of the resin particles are coated with metal, and can be appropriately selected according to the purpose. For example, the surface of the resin particles is nickel, copper, gold And particles coated with at least any one metal of palladium.
There is no restriction | limiting in particular as the coating method of the metal to the said resin particle, According to the objective, it can select suitably, For example, an electroless-plating method, sputtering method, etc. are mentioned.
There is no restriction | limiting in particular as a material of the said resin particle, According to the objective, it can select suitably, For example, a styrene- divinylbenzene copolymer, a benzoguanamine resin, a crosslinked polystyrene resin, an acrylic resin, a styrene-silica composite resin etc. Is mentioned.

-Insulation film-
The insulating film is formed from an active energy ray-curable resin composition. Before the anisotropic conductive film is used for anisotropic conductive connection, the insulating film is not cured by active energy rays.
The insulating film only needs to have an insulating property that does not cause conduction between the particles when a plurality of the particles are in contact with each other in an unpressurized state.

-Active energy ray curable resin composition-
The active energy ray-curable resin composition is not particularly limited and may be appropriately selected depending on the intended purpose. For example, it contains at least a (meth) acrylate resin and a photopolymerization initiator, and further required. Depending on the situation, other components are contained.

--- (Meth) acrylate resin ---
The (meth) acrylate resin is a resin containing at least one of an acrylate group and a methacrylate group.
In the (meth) acrylate resin, the (meth) acrylate group is polymerized by the radical species generated from the photopolymerization initiator and cured.
Examples of the (meth) acrylate resin include epoxy (meth) acrylate resin and urethane (meth) acrylate resin.

--- Photopolymerization initiator ---
Examples of the photopolymerization initiator include the following compounds.
Benzophenone Benzoin and its alkyl ethers (for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc.)
Acetophenones (for example, acetophenone, hydroxyphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy 2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, etc.)
Anthraquinones (for example, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, etc.)

--- Other ingredients ---
As said other component, monofunctional (meth) acrylate etc. are mentioned, for example.

There is no restriction | limiting in particular as an average particle diameter of the said particle | grains, Although it can select suitably according to the objective, 1 micrometer-30 micrometers are preferable, 2 micrometers-10 micrometers are more preferable, and 3 micrometers-6 micrometers are especially preferable.
The average particle diameter can be determined, for example, by measuring the particle diameter of 50 particles using a scanning electron microscope (SEM) and arithmetically averaging them.

  The average particle diameter of the particles is preferably less than the average thickness of the conductive particle-containing layer.

The particles can be produced, for example, by coating the conductive core material with the active energy ray-curable resin composition.
There is no restriction | limiting in particular as the method of the said coating | cover, According to the objective, it can select suitably, For example, the dry system etc. which utilized the physicochemical change by mechanical energy are mentioned.
Examples of the apparatus capable of forming the insulating film on the surface of the conductive core by the dry method include, for example, Mechanomill (trade name, manufactured by Tokuju Kogakusho Co., Ltd.), Hybridizer (manufactured by Nara Machinery Co., Ltd., trade name: NHS series).
In the dry method, for example, the particles can be obtained by treating the conductive core material and the powdered active energy ray-curable resin composition with the apparatus.

<< Thermosetting resin >>
There is no restriction | limiting in particular as said thermosetting resin, According to the objective, it can select suitably, For example, an epoxy resin, an acrylic resin, etc. are mentioned.

  There is no restriction | limiting in particular as said epoxy resin, According to the objective, it can select suitably, For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, those modified epoxy resins etc. are mentioned. .

  There is no restriction | limiting in particular as said acrylic resin, According to the objective, it can select suitably, For example, an acrylic compound, liquid acrylate, etc. are mentioned.

  Among these, the epoxy resin is preferable because the thermosetting resin is difficult to be cured by active energy rays when combined with an anionic curing agent described later.

  There is no restriction | limiting in particular as content of the said thermosetting resin in the said electroconductive particle content layer, Although it can select suitably according to the objective, 10 mass with respect to 100 mass parts of the said electroconductive particle content layer. Part-50 mass parts is preferable, and 20 mass parts-40 mass parts is more preferable.

<< Curing agent >>
The curing agent is not particularly limited as long as it is a curing agent that cures the thermosetting resin, and can be appropriately selected according to the purpose. Examples thereof include a cationic curing agent and an anionic curing agent. It is done.
Among these, the curing agent is preferably an anionic curing agent in that active species are not easily generated by active energy rays.

The cationic curing agent is not particularly limited as long as it is a curing agent that generates cationic species by heat and cationically cures the thermosetting resin, and can be appropriately selected according to the purpose. For example, onium Examples include salt.
Examples of the onium salt include a sulfonium salt and an iodonium salt.
Examples of the sulfonium salt include a triarylsulfonium salt.
The counter anion in the onium salt is not particularly limited and may be appropriately selected depending on the purpose. For example, SbF ₆ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ^{— and the} like.

The anionic curing agent is not particularly limited as long as it is a curing agent that anionically cures the thermosetting resin by heat, and can be appropriately selected according to the purpose. For example, imidazole curing agent, polythiol curing agent And amine curing agents.
Among these, an imidazole curing agent is preferable because it is excellent in curability at low temperatures.

  Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino. -6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid Examples include adducts.

  Examples of the polythiol curing agent include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, dipentaerythritol hexa-3-mercaptopropionate, and the like.

  Examples of the amine curing agent include hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5] undecane, and bis. (4-aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenyl sulfone and the like can be mentioned.

  There is no restriction | limiting in particular as content of the said hardening | curing agent in the said electroconductive particle content layer, Although it can select suitably according to the objective, 20 mass parts-with respect to 100 mass parts of the said electroconductive particle content layer. 60 mass parts is preferable, and 30 mass parts-50 mass parts is more preferable.

<< Other ingredients >>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, film forming resin, a silane coupling agent, etc. are mentioned.

-Film forming resin-
There is no restriction | limiting in particular as said film formation resin, According to the objective, it can select suitably, For example, phenoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin Resin etc. are mentioned. The film forming resin may be used alone or in combination of two or more. Among these, phenoxy resin is preferable from the viewpoint of film forming property, processability, and connection reliability.
Examples of the phenoxy resin include a resin synthesized from bisphenol A and epichlorohydrin.
As the phenoxy resin, an appropriately synthesized product or a commercially available product may be used.

  There is no restriction | limiting in particular as content of the said film formation resin in the said electroconductive particle content layer, Although it can select suitably according to the objective, 10 mass parts with respect to 100 mass parts of the said electroconductive particle content layer. -50 mass parts is preferable, and 20 mass parts-40 mass parts is more preferable.

-Silane coupling agent-
The silane coupling agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an epoxy silane coupling agent, an acrylic silane coupling agent, a thiol silane coupling agent, and an amine silane. A coupling agent etc. are mentioned.

  There is no restriction | limiting in particular as content of the said silane coupling agent in the said electroconductive particle content layer, Although it can select suitably according to the objective, It is 0.00 with respect to 100 mass parts of the said electroconductive particle content layer. 1 mass part-3.0 mass parts are preferable, and 0.5 mass part-2.0 mass parts are more preferable.

There is no restriction | limiting in particular as average thickness of the said electroconductive particle content layer, Although it can select suitably according to the objective, 1 micrometer-30 micrometers are preferable, 3 micrometers-10 micrometers are more preferable, and 5 micrometers-8 micrometers are especially preferable.
Here, the said average thickness is an arithmetic mean value at the time of measuring the thickness of five places of the said electroconductive particle content layer arbitrarily.

  It is preferable that the average thickness of the conductive particle-containing layer is less than the average thickness of the insulating adhesive layer in that both prevention of shorting between adjacent electrodes and conduction between counter electrodes can be achieved at a high level. The difference between the average thickness of the conductive particle-containing layer and the average thickness of the insulating adhesive layer [(average thickness of the insulating adhesive layer) − (average thickness of the conductive particle-containing layer)] is 2 μm to 15 μm. More preferably, 4 μm to 10 μm is particularly preferable.

<Insulating adhesive layer>
The insulating adhesive layer contains at least a thermosetting resin, preferably contains a curing agent, and further contains other components as necessary.

<< Thermosetting resin >>
There is no restriction | limiting in particular as said thermosetting resin, According to the objective, it can select suitably, For example, an epoxy resin, an acrylic resin, etc. are mentioned.

Examples of the epoxy resin include the epoxy resin exemplified in the description of the thermosetting resin of the conductive particle-containing layer.
As said acrylic resin, the said acrylic resin etc. which were illustrated in description of the said thermosetting resin of the said electroconductive particle content layer are mentioned, for example.
Among these, the thermosetting resin is preferably an epoxy resin in that it is hard to be cured by active energy rays.

  There is no restriction | limiting in particular as content of the said thermosetting resin in the said insulating contact bonding layer, Although it can select suitably according to the objective, 5 mass parts-with respect to 100 weight parts of the said insulating contact bonding layers 45 mass parts is preferable, and 15 mass parts-35 mass parts is more preferable.

<< Curing agent >>
The curing agent is not particularly limited as long as it is a curing agent that cures the thermosetting resin, and can be appropriately selected according to the purpose. Examples thereof include a cationic curing agent and an anionic curing agent. It is done.
Among these, the curing agent is preferably an anionic curing agent in that active species are not easily generated by active energy rays.

  The cationic curing agent is not particularly limited as long as it is a curing agent that generates cationic species by heat and cationically cures the thermosetting resin, and can be appropriately selected according to the purpose. The said hardening | curing agent etc. which were illustrated in description of the said hardening | curing agent of an electroconductive particle content layer are mentioned.

  The anionic curing agent is not particularly limited as long as it is a curing agent that anionically cures the thermosetting resin by heat, and can be appropriately selected according to the purpose. For example, the conductive particle-containing layer Examples include the anionic curing agent exemplified in the description of the curing agent.

  The content of the curing agent in the insulating adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose. Part is preferable, and 30 to 50 parts by mass is more preferable.

<< Other ingredients >>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, film forming resin, a silane coupling agent, etc. are mentioned.

-Film forming resin-
There is no restriction | limiting in particular as said film formation resin, According to the objective, it can select suitably, For example, the said film formation resin etc. which were illustrated in description of the said electroconductive particle content layer are mentioned. As the film-forming resin, a phenoxy resin is preferable from the viewpoint of film forming property, processability, and connection reliability.

  The content of the film-forming resin in the insulating adhesive layer is not particularly limited and may be appropriately selected depending on the intended purpose. A mass part is preferable and 25 mass parts-45 mass parts are more preferable.

-Silane coupling agent-
The silane coupling agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an epoxy silane coupling agent, an acrylic silane coupling agent, a thiol silane coupling agent, and an amine silane. A coupling agent etc. are mentioned.

  There is no restriction | limiting in particular as content of the said silane coupling agent in the said insulating contact bonding layer, Although it can select suitably according to the objective, 0.1 mass with respect to 100 mass parts of said insulating contact bonding layers. Part to 3.0 parts by weight is preferable, and 0.5 part to 2.0 parts by weight is more preferable.

There is no restriction | limiting in particular as average thickness of the said insulating contact bonding layer, Although it can select suitably according to the objective, 5 micrometers-50 micrometers are preferable, 7 micrometers-30 micrometers are more preferable, and 10 micrometers-15 micrometers are especially preferable.
Here, the said average thickness is an arithmetic mean value at the time of measuring the thickness of five places of the said insulating contact bonding layers arbitrarily.

  There is no restriction | limiting in particular as average thickness of the said anisotropic conductive film, According to the objective, it can select suitably.

(Connection method)
The connection method of the present invention includes at least a first arrangement step, a second arrangement step, an active energy ray irradiation step, and a heating and pressing step, and further includes other steps as necessary.
The connection method is a connection method in which the wiring of the wiring board and the terminal of the electronic component are connected by an anisotropic conductive film.

<First arrangement step>
The first disposing step is not particularly limited as long as it is a step of disposing the anisotropic conductive film of the present invention on the wiring of the wiring board, and can be appropriately selected according to the purpose.
In the first arrangement step, it is preferable that the anisotropic conductive film is arranged on the wiring of the wiring board so that the conductive particle-containing layer is in contact with the wiring.

<< wiring board >>
The wiring board includes at least a board and wiring, and further includes other members as necessary.

-Board-
The substrate is not particularly limited as long as it is a substrate that transmits active energy rays, and can be appropriately selected according to the purpose. Examples thereof include a plastic substrate and a glass substrate.
There is no restriction | limiting in particular as a shape, a magnitude | size, and a structure of the said board | substrate, According to the objective, it can select suitably.
Here, “transmitting active energy rays” means that active energy rays having a wavelength necessary for curing a curing component (for example, (meth) acrylate resin) in the active energy ray-curable resin composition, Any material may be used as long as it transmits to the extent necessary for the curing component to cure, and the transmittance of the active energy ray having the above wavelength does not need to be 100%.

−Wiring−
The wiring is not particularly limited as long as it is a wiring that does not transmit the active energy ray, and can be appropriately selected according to the purpose.
The wiring is arranged on the substrate.
Examples of the material of the wiring include gold, silver, copper, and aluminum.
There is no restriction | limiting in particular as a shape, a magnitude | size, and a structure of the said wiring, According to the objective, it can select suitably.
Here, “does not transmit active energy rays” means that active energy rays having a wavelength necessary for curing a curing component (for example, (meth) acrylate resin) in the active energy ray-curable resin composition, Any material that does not transmit the cured component to the extent that it does not cure may be used, and the transmittance of the active energy ray having the above-described wavelength does not need to be 0%. However, the wiring preferably has a transmittance of 0% for the active energy rays.

<Second arrangement step>
The second arrangement step is not particularly limited as long as it is a step of arranging the electronic component on the anisotropic conductive film so that the terminals of the electronic component are in contact with the anisotropic conductive film. However, the anisotropic conductive film is temporarily heated and pressed at a temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and as high as possible. It is preferable that the fixing process is included in that the prevention of a short circuit between adjacent electrodes and the conduction between the counter electrodes can be highly compatible. In this case, it is preferable to press at a pressure higher than usual (for example, 5 MPa to 40 MPa). Further, the heating and pressing time is preferably 0.5 second to 2 seconds.
Here, the “curing temperature of the thermosetting resin” is a temperature indicating the lowest melt viscosity when the melt viscosity is measured with a rheometer (temperature increase rate: 30 ° C./min).
Moreover, as "the temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and as high as possible", the curing temperature is preferably less than the curing temperature and the curing temperature of -10 ° C or more, less than the curing temperature and The curing temperature is more preferably −5 ° C. or higher.

<< Electronic parts >>
The electronic component is not particularly limited as long as it is an electronic component having a terminal to be connected, and can be appropriately selected according to the purpose. Examples thereof include an IC chip, a TAB tape, and a liquid crystal panel. It is done. Examples of the IC chip include a liquid crystal screen control IC chip in a flat panel display (FPD).

<Active energy ray irradiation process>
The active energy ray irradiation step is not particularly limited as long as it is a step of irradiating the anisotropic conductive film with the active energy ray from the wiring board side, and can be appropriately selected according to the purpose.

There is no restriction | limiting in particular as said active energy ray, Although it can select suitably according to the objective, A ultraviolet-ray is preferable at the point which hardens | cures the said insulating film which coat | covers the said electroconductive core material. There is no restriction | limiting in particular as a wavelength of the said ultraviolet-ray, According to the objective, it can select suitably, For example, 200 nm-400 nm etc. are mentioned.
There is no restriction | limiting in particular as an irradiation source of the said active energy ray, According to the objective, it can select suitably, For example, an LED lamp, a YAG laser, a xenon lamp, a halogen lamp etc. are mentioned.
There is no restriction | limiting in particular as irradiation amount of the said active energy ray, According to the objective, it can select suitably.

By performing the active energy ray irradiation step, the insulating film on the particles between adjacent electrodes (between wirings on the wiring board) is cured. On the other hand, the insulating film on the particles between the counter electrodes (between the wiring of the wiring board and the terminals of the electronic component) is not cured.
Therefore, at the time of heating and pressing performed after the active energy ray irradiation step, the insulating film on the particles between the adjacent electrodes is not broken, and the insulation between the adjacent electrodes is maintained. On the other hand, since the insulating coating on the particles between the counter electrodes is broken and the conductive core material is in contact with the wiring and the terminals, conduction between the counter electrodes is obtained.

<Heat pressing process>
The heating and pressing step is not particularly limited as long as it is a step of heating and pressing the electronic component with a heating and pressing member, and can be appropriately selected according to the purpose.

Examples of the heating and pressing member include a pressing member having a heating mechanism. Examples of the pressing member having the heating mechanism include a heat tool.
There is no restriction | limiting in particular as temperature of the said heating, Although it can select suitably according to the objective, 130 to 200 degreeC is preferable.
There is no restriction | limiting in particular as the pressure of the said press, Although it can select suitably according to the objective, 40 MPa-100 MPa are preferable.
There is no restriction | limiting in particular as time of the said heating and a press, Although it can select suitably according to the objective, 3 seconds-15 seconds are preferable.

An example of the connection method of the present invention will be described with reference to FIGS. 1A to 1D.
First, as shown in FIG. 1A, an anisotropic conductive film having a conductive particle-containing layer 3 and an insulating adhesive layer 4 is arranged on a wiring board having a substrate 1 and a wiring 2 (first arrangement). Process). At this time, the conductive particle-containing layer 3 is disposed so as to be in contact with the wiring 2.
The conductive particle-containing layer 3 has a thermosetting resin and particles. The particles include a conductive core material 31 and an insulating film 32 formed on the surface of the conductive core material 31.

Subsequently, as shown in FIG. 1B, the electronic component 5 is arranged on the anisotropic conductive film so that the terminals 6 of the electronic component 5 are in contact with the anisotropic conductive film (second arrangement step). .
At this time, it is preferable to include a temporary fixing process in which the anisotropic conductive film is heated and pressed at a temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and as high as possible.

Then, as shown to FIG. 1C, an active energy ray is irradiated to the said anisotropic conductive film from the said wiring board side (active energy ray irradiation process).
Then, the insulating film 32 on the particles between the adjacent electrodes (between the wirings 2 on the wiring board) is cured. On the other hand, the insulating film 32 on the particles between the counter electrodes (between the wiring 2 of the wiring board and the terminal 6 of the electronic component 5) is not cured.

Then, as shown to FIG. 1D, an electronic component is heated and pressed with a heating press member (heating press process).
If it does so, the insulating film 32 in the said particle | grains between adjacent electrodes will not be torn, but the insulation between adjacent electrodes will be maintained.
On the other hand, the insulating film 32 of the particles between the counter electrodes is broken when the particles are deformed. Then, since the conductive core material 31 comes into contact with the wiring 2 and the terminal 6, conduction between the counter electrodes is obtained.
When the same kind of thermosetting resin, film-forming resin, curing agent, etc. are used for the conductive particle-containing layer and the insulating adhesive layer, the conductive particle-containing layer and the insulating adhesive layer are used after the heating and pressing step. The interface with becomes unclear and almost integrated.

  Since the anisotropic conductive film of the present invention and the connection method of the present invention can achieve both short-circuit prevention between adjacent electrodes and conduction between counter electrodes, the pitch between adjacent electrodes is narrow (so-called fine pitch). It can be suitably used for connection. The pitch can be 20 μm or less, and can be 15 μm.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Example 1)
<Preparation of particles>
The particles were prepared by coating a conductive core material with an active energy ray-curable resin composition. Specifically, it was produced as follows.
90 parts by mass of conductive core material (AUL704, manufactured by Sekisui Chemical Co., Ltd., average particle size 4 μm) and powdered active energy ray-curable resin composition [containing urethane (meth) acrylate resin and photopolymerization initiator] 10 The mass part was placed in a hybridizer (trade name: NHS series, manufactured by Nara Machinery Co., Ltd.) and processed. The processing conditions in the hybridizer were a rotational speed of 16,000 rpm and a reaction vessel temperature of 60 ° C.
The average particle diameter of the obtained particles was 4.1 μm.

(Production Example 2)
<Preparation of particles>
Particles were obtained in the same manner as in Production Example 1 except that the urethane (meth) acrylate resin was replaced with an epoxy (meth) acrylate resin in Production Example 1.
The average particle diameter of the obtained particles was 4.1 μm.

(Production Example 3)
<Preparation of particles>
In Production Example 1, the material for covering the conductive core material is changed from a powdery active energy ray-curable resin composition (containing a urethane (meth) acrylate resin and a photopolymerization initiator) to a urethane (meth) acrylate resin. Particles were obtained in the same manner as in Production Example 1, except that only the above was used.
The average particle diameter of the obtained particles was 4.1 μm.

Example 1
<Preparation of anisotropic conductive film>
-Production of conductive particle-containing layer-
Phenoxy resin (Product name: YP50, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) 30 parts by mass, Epoxy resin (Product name: EP828, manufactured by Mitsubishi Chemical Co., Ltd.) 30 parts by mass, Amine-based curing agent (Product name: PHX3941HP, manufactured by Asahi Kasei Corporation) , Imidazole curing agent) 40 parts by mass, silane coupling agent (product name: A-187, manufactured by Momentive Performance Materials) 1 part by mass, and 35 parts by mass of particles produced in Production Example 1 , Awatori Nerita, manufactured by Shinky Corp.). The blended mixture was applied onto a silicone-treated PET (polyethylene terephthalate) so that the average thickness after drying was 5 μm, and dried at 70 ° C. for 5 minutes to prepare a conductive particle-containing layer.

-Production of insulating adhesive layer-
Phenoxy resin (Product name: YP50, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) 25 parts by mass, Epoxy resin (Product name: EP828, manufactured by Mitsubishi Chemical Co., Ltd.) 35 parts by mass, Amine-based curing agent (Product name: PHX3941HP, manufactured by Asahi Kasei Corporation) 40 parts by mass of imidazole curing agent) and 1 part by mass of silane coupling agent (product name: A-187, manufactured by Momentive Performance Materials Co., Ltd.) with a stirrer (spinning revolving mixer, Aritori Kentaro, manufactured by Shinky Co., Ltd.) Used to mix evenly. The blended mixture was applied onto a silicone-treated PET (polyethylene terephthalate) so that the average thickness after drying was 15 μm, and dried at 70 ° C. for 5 minutes to produce an insulating adhesive layer.

  The obtained conductive particle-containing layer and the insulating adhesive layer were bonded together to obtain an anisotropic conductive film.

<Manufacture of joined body>
COG (Chip on Glass) mounting was performed by the following method.
A glass substrate having a thickness of 0.7 mm on which an ITO comb wiring was formed was used as the wiring substrate.
As an electronic component, a test IC chip (size: 1.8 mm × 20 mm, thickness: 0.5 mm, gold-plated bump size: 13 μm × 80 μm, bump height: 15 μm, bump space: 12 μm) was used.
On the wiring of the wiring substrate, an anisotropic conductive film was disposed so that the conductive particle-containing layer was in contact with the wiring. Subsequently, the electronic component is disposed on the insulating adhesive layer of the anisotropic conductive film, and a Teflon (registered trademark) sheet having an average thickness of 50 μm is used as a buffer material. Under the conditions, the electronic component was heated and pressed, and temporarily fixed. Subsequently, UV irradiation (400 mW × 2 sec irradiation, UV LED light source manufactured by OMRON Corporation, ZUV-C20H, ZUV-H20MC was used) was performed on the anisotropic conductive film from the wiring board side. Subsequently, a Teflon (registered trademark) sheet having an average thickness of 50 μm is used as a buffer material, and the electronic component is heated and pressed under the conditions of 200 ° C., 60 MPa, and 5 seconds with a heating tool to perform connection, Obtained.

<Evaluation>
It used for the following evaluation. The results are shown in Table 1-1.

<< Short occurrence probability >>
About the joined body produced above, the resistance value (Ω) between the terminals of 16ch was measured using a high resistance meter (product number: high resistance meter 4339B, manufactured by Agilent). Specifically, a ch having a resistance value of 10 ⁸ Ω or less when a voltage of 30 V was applied by the two-terminal method was regarded as a short, and evaluation was performed according to the following evaluation criteria.
〔Evaluation criteria〕
○: The number of channels with a short circuit is 0
Δ: The number of channels with a short circuit is 1-2
X: The number of channels in which a short circuit occurred is 3 to 16

<< Conduction resistance value >>
About the joined body produced above, the resistance value (Ω) between the 30ch terminal and the ITO wiring was measured using a digital multimeter (product number: digital multimeter 7555, manufactured by Yokogawa Electric Corporation). Specifically, the resistance value (conduction resistance value, Ω) after lapse of 500 hours was measured at 85 ° C. and 85% RH when a current of 1 mA was passed by the four-terminal method. Evaluation was performed according to the following evaluation criteria.
〔Evaluation criteria〕
○: Less than 10Ω Δ: 10Ω or more and less than 50Ω ×: 50Ω or more

(Examples 2-7 and Comparative Examples 1-3)
<Production of anisotropic conductive film and production of joined body>
In Example 1, the composition of the conductive particle-containing layer (ACF layer), the composition of the insulating adhesive layer (NCF layer), and their average thickness, heating and pressing conditions during temporary fixing, and the presence or absence of UV irradiation, Except having changed as described in Table 1-1 and Table 1-2, it carried out similarly to Example 1, and produced the anisotropic conductive film and manufacture of the conjugate | zygote.
Evaluation similar to Example 1 was performed. The results are shown in Table 1-1 and Table 1-2.

表１−１、及び表１−２中、ＡＵＬ−７０４は、導電性粒子（Ｎｉ／Ａｕメッキ、樹脂コア、積水化学工業株式会社製、平均粒子径４μｍ）である。ＰＫＨＨは、フェノキシ樹脂（巴化学工業株式会社製）である。ＪＥＲ８０６は、ビスフェノールＦ型エポキシ樹脂（三菱化学株式会社製）である。

In Table 1-1 and Table 1-2, AUL-704 is conductive particles (Ni / Au plating, resin core, manufactured by Sekisui Chemical Co., Ltd., average particle diameter 4 μm). PKHH is a phenoxy resin (manufactured by Sakai Chemical Industry Co., Ltd.). JER806 is a bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation).

In Examples 1 to 7, it was possible to achieve both prevention of occurrence of short circuit and securing of conduction.
When the average thickness of the conductive particle-containing layer was 5 μm to 8 μm, particularly excellent results were obtained (see Examples 1-2 and Examples 5-7).
When the average thickness of the conductive particle-containing layer exceeds 8 μm, the trapping property of the particles between the counter electrodes is slightly lowered. Further, the active energy rays are diffracted from the side surface of the wiring and reach the particles between the counter electrodes, and the insulating film of the particles between the counter electrodes is also slightly cured. Furthermore, it becomes difficult for active energy rays to reach particles far from the substrate. According to these results, when the average thickness of the conductive particle-containing layer exceeded 8 μm, prevention of short-circuiting and securing of conduction were reduced as compared with the case where the average thickness of the conductive particle-containing layer was 5 μm to 8 μm.
In the second arrangement step, the anisotropic conductive film is formed at a temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and as high as possible (less than the curing temperature and the curing temperature of −10 ° C. or more). When heated and pressed (see Examples 1-2 and Examples 5-7), the conduction resistance value was superior to when not (Example 4).
In Comparative Examples 1 to 4, prevention of short-circuiting and securing of conduction were not compatible. Even in Comparative Example 3 using conventional insulating coat conductive particles, it was not possible to cope with a fine pitch of 12 μm, and it was impossible to achieve both prevention of short-circuiting and ensuring of conduction.

  Since the anisotropic conductive film of the present invention and the connection method of the present invention can achieve both short-circuit prevention between adjacent electrodes and conduction between counter electrodes, the pitch between adjacent electrodes is narrow (so-called fine pitch). It can be suitably used for connection.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Wiring 3 Conductive particle content layer 31 Conductive core material 32 Insulating film 4 Insulating adhesive layer 5 Electronic component 6 Terminal

Claims (6)

A conductive core material, particles having an insulating film formed from an active energy ray-curable resin composition on the surface of the conductive core material, and a conductive particle-containing layer containing a thermosetting resin;
An insulating adhesive layer containing a thermosetting resin;
An anisotropic conductive film comprising:   The anisotropic conductive film according to claim 1, wherein the average thickness of the conductive particle-containing layer is less than the average thickness of the insulating adhesive layer.   The anisotropic conductive film according to claim 1, wherein the active energy ray-curable resin composition contains a (meth) acrylate resin. The conductive particle-containing layer contains an anionic curing agent,
The insulating adhesive layer contains an anionic curing agent;
The anisotropic conductive film in any one of Claim 1 to 3. A connection method for connecting the wiring of a wiring board having a substrate that transmits active energy rays and a wiring that does not transmit active energy rays, and a terminal of an electronic component,
A first disposing step of disposing the anisotropic conductive film according to any one of claims 1 to 4 on the wiring of the wiring substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film so that the terminal of the electronic component is in contact with the anisotropic conductive film;
An active energy ray irradiating step of irradiating the anisotropic conductive film with the active energy ray from the wiring board side;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member.   The second disposing step includes a temporary fixing process in which the anisotropic conductive film is heated and pressed at a temperature lower than the curing temperature of the thermosetting resin of the conductive particle-containing layer and at the curing temperature of -10 ° C or higher. The connection method described in 1.

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