JP2014160546A - Anisotropic conductive film, connection method and joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive film or the like which is excellent in storage stability, and connection reliability at the time of connection at a low temperature.SOLUTION: Disclosed is an anisotropic conductive film which performs anisotropic conductive connection between a terminal of a substrate and a terminal of an electrical component. This film has a conductive particle-containing layer containing a conductive particle, a film forming resin, a hardening resin and a hardener, and an insulating adhesive layer containing the film forming resin, the hardening resin and the hardener. Only the insulating adhesive layer contains a thiol compound, and the conductive particle has Cu on the surface.

Description

  The present invention relates to an anisotropic conductive film, a connection method, and a joined body.

  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 starts, for example, when connecting a terminal of a flexible printed circuit (FPC) or IC (Integrated Circuit) chip and an electrode formed on a glass substrate of an LCD (Liquid Crystal Display) panel. In other words, it is used when various terminals are bonded and electrically connected.

  The anisotropic conductive connection for electrically connecting the terminal of the substrate and the terminal of the electronic component using the anisotropic conductive film is usually performed by sandwiching the anisotropic conductive film between the substrate and the electronic component. This is done by heating and pressing the isotropic conductive film. As heating temperature in this case, it is about 170 degreeC-200 degreeC, for example. This heat can affect the substrate and electronic components. Further, misalignment may occur at the time of connection due to a difference in thermal expansion coefficient between the substrate and the electronic component.

Therefore, there is a demand for a method for anisotropic conductive connection between the terminal of the substrate and the terminal of the electronic component at a low temperature. For example, an insulating adhesive layer containing a polymerizable acrylic compound, a film-forming resin and a polymerization initiator, and a conductive particle-containing layer containing a polymerizable acrylic compound, a film-forming resin, a polymerization initiator and conductive particles, An anisotropic conductive film in which the insulating adhesive layer and the conductive particle-containing layer each contain a thiol compound has been proposed (see, for example, Patent Document 1). .
In the proposed technique, connection at 130 ° C. is performed. However, in recent years, connection at a lower temperature (for example, 110 ° C.) has been demanded. In the proposed technique, there is a problem that connection reliability is lowered when attempting to connect at such a lower temperature.

  Moreover, the anisotropic conductive film containing a thiol compound generally has a problem that storage stability is lowered.

  Therefore, it is currently required to provide an anisotropic conductive film excellent in storage stability and connection reliability when connected at a low temperature, a connection method using the anisotropic conductive film, and a joined body. It is.

JP 2011-32491 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention aims to provide an anisotropic conductive film excellent in storage stability and connection reliability when connected at a low temperature, a connection method using the anisotropic conductive film, and a joined body. And

Means for solving the problems are as follows. That is,
<1> An anisotropic conductive film for anisotropically conductively connecting a terminal of a substrate and a terminal of an electronic component,
A conductive particle-containing layer containing conductive particles, a film-forming resin, a curable resin, and a curing agent;
An insulating adhesive layer containing a film-forming resin, a curable resin, and a curing agent;
Only the insulating adhesive layer contains a thiol compound,
The conductive particle is an anisotropic conductive film characterized by having Cu on the surface.
<2> The anisotropic conductive film according to <1>, wherein the content of the thiol compound in the insulating adhesive layer is 0.25% by mass to 15% by mass.
<3> The anisotropic conductive film according to any one of <1> to <2>, wherein the conductive particles are at least one of Cu particles and Cu-coated resin particles.
<4> A connection method for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component,
A first disposing step of disposing the anisotropic conductive film according to any one of <1> to <3> on a terminal of the substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film such that a terminal of the electronic component is in contact with the anisotropic conductive film;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member.
<5> A substrate having terminals, an electronic component having terminals, and an anisotropy interposed between the substrate and the electronic component to electrically connect the terminal of the substrate and the terminal of the electronic component A cured product of a conductive film,
The anisotropic conductive film is the anisotropic conductive film according to any one of <1> to <3>.

  According to the present invention, the anisotropic conductive film which can solve the above-mentioned problems and can achieve the above-mentioned object, and is excellent in storage stability and connection reliability when connected at a low temperature, and the anisotropic A connection method using a conductive film and a joined body can be provided.

FIG. 1 is an explanatory diagram illustrating a connection reliability measurement method in the embodiment. FIG. 2 is an explanatory view showing a method of measuring the adhesive strength in the example.

(Anisotropic conductive film)
The anisotropic conductive film of the present invention is an anisotropic conductive film for anisotropically connecting a terminal of a substrate and a terminal of an electronic component, and has at least a conductive particle-containing layer and an insulating adhesive layer. Furthermore, it has other layers as required.
In the anisotropic conductive film, only the insulating adhesive layer contains a thiol compound.
The conductive particles have Cu on the surface.

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

-Conductive particles-
The conductive particles are not particularly limited as long as they are conductive particles having Cu on the surface, and can be appropriately selected according to the purpose. Examples thereof include Cu particles and Cu-coated resin particles.

The Cu-coated resin particles are not particularly limited as long as the surfaces of the resin particles are coated with Cu, and can be appropriately selected according to the purpose.
There is no restriction | limiting in particular as the coating method of Cu 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.

  The conductive particles only need to have conductivity during anisotropic conductive connection. For example, even if the surface of the conductive particles is an insulating film, as long as the particles are deformed and exposed to anisotropic conductive connection, the conductive particles are exposed. It is.

There is no restriction | limiting in particular as an average particle diameter of the said electroconductive particle, Although it can select suitably according to the objective, 1 micrometer-30 micrometers are preferable, 2 micrometers-25 micrometers are more preferable, and 3 micrometers-10 micrometers are especially preferable.
The average particle diameter is an average value of particle diameters measured for 10 conductive particles arbitrarily.
The particle diameter can be measured, for example, by observation with a scanning electron microscope.

  There is no restriction | limiting in particular as content of the said electroconductive particle in the said electroconductive particle content layer, Although it can select suitably according to the objective, 0.1 mass%-30 mass% are preferable, and 2 mass%- 30 mass% is more preferable, 2 mass%-20 mass% is still more preferable, and 2 mass%-10 mass% are especially preferable.

-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, 30 mass%-60 mass% are preferable, 35 mass%-55 mass% % Is more preferable.

-Curable resin-
There is no restriction | limiting in particular as said curable resin, According to the objective, it can select suitably, For example, an epoxy resin, a polymeric acrylic compound, etc. are mentioned.

--- Epoxy resin--
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, alicyclic type An epoxy resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

--Polymerizable acrylic compound--
There is no restriction | limiting in particular as said polymeric acrylic compound, According to the objective, it can select suitably, For example, polyethyleneglycol diacrylate, phosphate ester type acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4 -Hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, bisphenoxyethanol full orange acrylate, 2-acryloyloxyethyl succinic acid, lauryl acrylate, stearyl acrylate, isobornyl acrylate, tricyclodecane dimethanol dimethacrylate , Cyclohexyl acrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, tetrahydrofurfuryl acrylate DOO, o- phthalic acid diglycidyl ether acrylate, ethoxylated bisphenol A dimethacrylate, bisphenol A type epoxy acrylate, urethane acrylate, epoxy acrylate, and can be exemplified methacrylate corresponding thereto. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as content of the said curable resin in the said electroconductive particle content layer, Although it can select suitably according to the objective, 30 to 80 mass% is preferable, and 35 to 65 mass% is preferable. % Is more preferable.

-Curing agent-
There is no restriction | limiting in particular as said hardening | curing agent, According to the objective, it can select suitably, For example, imidazoles, an organic peroxide, an anionic hardening | curing agent, a cationic hardening | curing agent etc. are mentioned.

Examples of the imidazoles include 2-ethyl 4-methylimidazole.
Examples of the organic peroxide include lauroyl peroxide, butyl peroxide, benzyl peroxide, dilauroyl peroxide, dibutyl peroxide, peroxydicarbonate, and benzoyl peroxide.
Examples of the anionic curing agent include organic amines.
Examples of the cationic curing agent include a sulfonium salt, an onium salt, and an aluminum chelating agent.
Among these, an organic peroxide is preferable and dilauroyl peroxide is more preferable in terms of excellent storage stability.

  The combination of the curable resin and the curing agent is not particularly limited and may be appropriately selected depending on the purpose. The combination of the epoxy resin and the cationic curing agent, the polymerizable acrylic compound, A combination with the organic peroxide is preferred.

  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, 1 mass%-10 mass% are preferable, and 2 mass%-5 mass% are preferable. 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, a silane coupling agent, a filler, a softening agent, a hardening accelerator, anti-aging agent, a coloring agent (a pigment, dye) ), Organic solvents, ion catchers and the like.
There is no restriction | limiting in particular as content of the said other component, According to the objective, it can select suitably.

There is no restriction | limiting in particular as average thickness of the said electroconductive particle content layer, Although it can select suitably by the relationship with the average particle diameter of the said electroconductive particle, and the average thickness of the said insulating contact bonding layer, 5 micrometers-30 micrometers. Is preferable, and 10 μm to 25 μm is more preferable. When the average thickness is less than 5 μm, the conductive particles may not be sufficiently filled between the terminals of the substrate and the terminals of the electronic component, and when it exceeds 30 μm, it may cause connection failure.
Here, the said average thickness is an average value at the time of measuring the thickness of five places of the said electroconductive particle content layer arbitrarily.

<Insulating adhesive layer>
The insulating adhesive layer contains at least a thiol compound, a film-forming resin, a curable resin, and a curing agent, and further contains other components as necessary.

-Thiol compound-
The thiol compound is not particularly limited as long as it is a compound containing a thiol group (mercapto group) and can be appropriately selected according to the purpose. However, from the viewpoint of reactivity and storage stability, pentaerythritol tetrakis is preferable. (3-mercaptopropionate) (PEMP), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate (TEMPIC), trimethylolpropane tris (3-mercaptopropionate) (TMMP), dipenta Erythritol hexakis (3-mercaptopropionate) (DPMP), 2-ethylhexyl-3-mercaptopropionate (EHMP), and tetraethylene glycol bis (3-mercaptopropionate) (EGMP-4) are preferred. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as content of the said thiol compound in the said insulating contact bonding layer, Although it can select suitably according to the objective, 0.25 mass%-15 mass% are preferable, 0.25 mass%- 10 mass% is more preferable, 0.5 mass%-10 mass% is still more preferable, and 2 mass%-7 mass% is especially preferable.

-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. The preferred embodiment is also the same.

  There is no restriction | limiting in particular as content of the said film formation resin in the said insulating contact bonding layer, Although it can select suitably according to the objective, 30 mass%-60 mass% are preferable, 35 mass%-55 mass% Is more preferable.

-Curable resin-
There is no restriction | limiting in particular as said curable resin, According to the objective, it can select suitably, For example, an epoxy resin, a polymeric acrylic compound, etc. are mentioned.
There is no restriction | limiting in particular as said epoxy resin, According to the objective, it can select suitably, For example, the said epoxy resin etc. which were illustrated in description of the said electroconductive particle content layer are mentioned.
There is no restriction | limiting in particular as said polymeric acrylic compound, According to the objective, it can select suitably, For example, the said polymeric acrylic compound etc. which were illustrated in description of the said electroconductive particle content layer are mentioned.

  There is no restriction | limiting in particular as content of the said curable resin in the said insulating contact bonding layer, Although it can select suitably according to the objective, 30 mass%-80 mass% are preferable, and 35 mass%-65 mass% are preferable. Is more preferable.

-Curing agent-
There is no restriction | limiting in particular as said hardening | curing agent, According to the objective, it can select suitably, For example, the said hardening | curing agent etc. which were illustrated in description of the said electroconductive particle content layer are mentioned. The preferred embodiment is also the same.

  The combination of the curable resin and the curing agent is not particularly limited and may be appropriately selected depending on the purpose. The combination of the epoxy resin and the cationic curing agent, the polymerizable acrylic compound, A combination with the organic peroxide is preferred.

  There is no restriction | limiting in particular as content of the said hardening | curing agent in the said insulating contact bonding layer, Although it can select suitably according to the objective, 1 mass%-10 mass% are preferable, and 2 mass%-5 mass% are preferable. More preferred.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a silane coupling agent, a filler, a softening agent, a hardening accelerator, anti-aging agent, a coloring agent (a pigment, dye) ), Organic solvents, ion catchers and the like.
There is no restriction | limiting in particular as content of the said other component, According to the objective, it can select suitably.

There is no restriction | limiting in particular as average thickness of the said insulating contact bonding layer, Although it can select suitably, 5 micrometers-30 micrometers are preferable, and 10 micrometers-25 micrometers are more preferable. When the average thickness is less than 5 μm, the resin filling rate between the terminals may decrease, and when it exceeds 30 μm, connection failure may occur.
Here, the said average thickness is an average value at the time of measuring the thickness of five places of the said insulating contact bonding layers arbitrarily.

<Board>
The substrate is not particularly limited as long as it is a substrate that has terminals and is an object of anisotropic conductive connection using the anisotropic conductive film, and can be appropriately selected according to the purpose. , Glass substrates having terminals, plastic substrates having terminals, and the like. The substrate may be a printed wiring board (PWB).
Examples of the glass substrate having the terminal include an ITO (Indium Tin Oxide) glass substrate, an IZO (Indium Zinc Oxide) glass substrate, and other glass pattern substrates. Among these, an ITO glass substrate and an IZO glass substrate are preferable.
There is no restriction | limiting in particular as a material and structure of the plastic substrate which has the said terminal, According to the objective, it can select suitably, For example, the rigid board | substrate which has a terminal, the flexible substrate which has a terminal, etc. are mentioned.

There is no restriction | limiting in particular as average thickness of the said board | substrate, Although it can select suitably according to the objective, 0.1 mm-1.0 mm are preferable, and 0.2 mm-0.8 mm are more preferable.
The said average thickness is an average value at the time of measuring the thickness of arbitrary 10 places of the said board | substrate.

<Electronic parts>
The electronic component is not particularly limited as long as the electronic component has a terminal and is an object of anisotropic conductive connection using the anisotropic conductive material, and can be appropriately selected according to the purpose. Examples thereof include IC (Integrated Circuit), TAB (Tape Automated Bonding) tape, COF (Chip-on-Flex, chip on flex), TCP (Tape carrier package, tape carrier package), and liquid crystal panel. Examples of the IC include a liquid crystal screen control IC chip in a flat panel display (FPD).
There is no restriction | limiting in particular as a shape of the said electronic component, According to the objective, it can select suitably, For example, when it sees from an upper surface, a rectangle, a square, etc. are mentioned.

(Connection method)
The connection method of the present invention includes at least a first arrangement step, a second arrangement step, and a heating and pressing step, and further includes other steps as necessary.
The connection method is a method in which the terminals of the substrate and the terminals of the electronic component are anisotropically conductively connected.

  There is no restriction | limiting in particular as said board | substrate and said electronic component, According to the objective, it can select suitably, For example, the said board | substrate illustrated by description of the said anisotropic conductive film of this invention, and the said electronic component are Each is listed.

<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 terminal of the substrate, and can be appropriately selected according to the purpose.
In the first arrangement step, the anisotropic conductive film is usually arranged on the terminal of the substrate so that the conductive particle-containing layer of the anisotropic conductive film is in contact with the terminal of the substrate. .
In the arrangement, heating and pressurization for temporary fixing may be performed. The heating temperature at this time is preferably a heating temperature at which the anisotropic conductive film is not cured.

<Second arrangement step>
The second placement step is not particularly limited as long as it is a step of placing the electronic component on the anisotropic conductive film so that terminals of the electronic component are in contact with the anisotropic conductive film, It can be appropriately selected according to the purpose.
In the second arranging step, the electronic component is usually arranged on the anisotropic conductive film so that the insulating adhesive layer of the anisotropic conductive film is in contact with a terminal of the electronic component.

<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 the temperature of the said heating, Although it can select suitably according to the objective, 110 to 140 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, 0.5 Mpa-10 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, 0.5 second-10 second are preferable.

(Joint)
The joined body of the present invention includes at least a substrate, an electronic component, and a cured product of an anisotropic conductive film, and further includes other members as necessary.

  There is no restriction | limiting in particular as said board | substrate and said electronic component, According to the objective, it can select suitably, For example, the said board | substrate illustrated by description of the said anisotropic conductive film of this invention, and the said electronic component are Each is listed.

The anisotropic conductive film is the anisotropic conductive film of the present invention.
The cured product of the anisotropic conductive film is interposed between the substrate and the electronic component to electrically connect the terminal of the substrate and the terminal of the electronic component.

  The joined body can be manufactured, for example, by the connection method of the present invention.

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

Example 1
<Preparation of anisotropic conductive film>
-Production of conductive particle-containing layer-
Phenoxy resin (product name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.) 40 parts by mass, bifunctional acrylic monomer (polyethylene glycol # 200 diacrylate, product name: A-200, manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass, urethane 20 parts by mass of acrylate (product name: U-2PPA, manufactured by Shin-Nakamura Chemical Co., Ltd.), 2 parts by mass of phosphate ester acrylate (product name: PM-2, manufactured by Nippon Kayaku Co., Ltd.), organic peroxide (dilauroyl) 3 parts by mass of peroxide) and 5 parts by mass of conductive particles (Cu particles, average particle diameter: 5 μm) were uniformly mixed using a stirrer (automatic revolution mixer, Aritori Nertaro, manufactured by Shinky Corporation). The blended composition was applied onto a silicone-treated PET (polyethylene terephthalate) so that the average thickness after drying was 17 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 Chemical Co., Ltd.) 45 parts by mass, bifunctional acrylic monomer (polyethylene glycol # 200 diacrylate, product name: A-200, manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass, urethane 20 parts by mass of acrylate (product name: U-2PPA, manufactured by Shin-Nakamura Chemical Co., Ltd.), 2 parts by mass of phosphate ester acrylate (product name: PM-2, manufactured by Nippon Kayaku Co., Ltd.), organic peroxide (dilauroyl) 3 parts by mass of peroxide) and a thiol compound (pentaerythritol tetrakis (3-mercaptopropionate), the amount corresponding to the content shown in Table 1) were mixed with a stirrer (spinning revolving mixer, Aritori Kentaro, manufactured by Shinky Corporation) ) To mix evenly. The blended mixture was applied onto silicone-treated PET (polyethylene terephthalate) so that the average thickness after drying was 18 μm, and dried at 70 ° C. for 5 minutes to produce an insulating adhesive layer.

  The conductive particle-containing layer and the insulating adhesive layer obtained above were laminated at a roll temperature of 45 ° C. using a roll laminator to obtain an anisotropic conductive film (ACF).

<Manufacture of joined body>
The joined body was manufactured by the following method.
As COF (chip-on-flex), COF for evaluation (Dexerials Corporation evaluation base material, 200 μm P (pitch), Cu 8 μmt (thickness) -Sn plating, 38 μmt (thickness) —S′perflex base material) was used.
As PWB (printed wiring board), PWB for evaluation (Dexerials Corporation evaluation base material, 200 μm P (pitch), Cu 35 μmt (thickness) —Au plating, FR-4 base material) was used.
On the evaluation PWB, the anisotropic conductive film slit to a width of 2 mm was arranged so that the conductive particle-containing layer was in contact with the evaluation PWB. When arranging, it was pasted at 80 ° C., 1 MPa, and 1 second. Subsequently, the evaluation COF was disposed on the anisotropic conductive film so as not to protrude from the anisotropic conductive film. Subsequently, the evaluation COP is heated and pressed under the conditions of 110 ° C., 3 MPa, and 5 seconds with a heating tool (width 2.0 mm) through a buffer material (silicone rubber, thickness 0.25 mm) to obtain a joined body. Got.

<Evaluation>
The following evaluation was performed. The results are shown in Table 1.

<< Connection reliability (conducting resistance) >>
The initial resistance value of the obtained bonded body and the resistance value after being allowed to stand at 85 ° C. and 85% RH for 500 hours were measured by the following method.
Specifically, as shown in FIG. 1, a resistance value when a current of 1 mA is passed by a four-terminal method using a digital multimeter (product number: Digital Melchometer 7555, manufactured by Yokogawa Electric Corporation) is measured. did. The resistance value was measured for 30 channels, and the maximum resistance value was taken as the measured value. The measurement results were evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: Less than 2Ω B: 2Ω or more and less than 5Ω C: 5Ω or more

<< Adhesive strength >>
As shown in FIG. 2, the manufactured joined body was subjected to a 90 degree peel test (JIS K6854-1) at a peel speed of 50 mm / min using a peel tester (manufactured by A & D Co., Ltd.). The peel strength was measured as the adhesive strength. The measurement results were evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: 8 N / cm or more B: 5 N / cm or more and less than 8 N / cm C: Less than 5 N / cm

<< Storage stability >>
The produced anisotropic conductive film was left in an oven at 40 ° C. for 24 hours. Using the anisotropic conductive film after being allowed to stand, a joined body was produced by the above method, and the connection reliability (initial) and the adhesive strength were evaluated.

<< Insulation >>
A sample was prepared by slitting an anisotropic conductive film to a width of 2 mm, and heating and pressing COF having electrodes of 50 μm pitch and PWB of 50 μm pitch under conditions of 110 ° C., 3 MPa, and 5 seconds. 100 identical samples were prepared and the occurrence rate of short circuit was measured.

(Examples 2 to 20 and Comparative Examples 1 to 5)
In Example 1, the kind and content of the conductive particles in the conductive particle-containing layer (A layer), the kind and content of the thiol compound in the conductive particle-containing layer, the insulating adhesive layer (N layer) Table 1 to Table 3 show the types and contents of the thiol compounds and the types of the organic peroxides in the conductive particle-containing layer and the insulating adhesive layer. Kind and content of particles, kind and content of thiol compound in conductive particle-containing layer, kind and content of thiol compound in insulating adhesive layer, and conductive particle-containing layer and insulating property An anisotropic conductive film was obtained in the same manner as in Example 1 except that the type of the organic peroxide in the adhesive layer was changed.
A bonded body was prepared in the same manner as in Example 1 using the obtained anisotropic conductive film and subjected to evaluation. The results are shown in Tables 1 to 3.

  In Tables 1 to 3, the A layer represents a conductive particle-containing layer. The N layer represents an insulating adhesive layer. Content represents content (mass%) in the layer.

In Tables 1 to 3, “Cu particles” in Examples and Comparative Examples are copper particles (average particle diameter of 5 μm) produced by an atomizing method.
The “resin particles” in Example 20 are copper plating resin particles obtained by electroless copper plating of benzoguanamine resin particles having an average particle diameter of 4.8 μm.
“Ni particles” in Comparative Example 4 are nickel particles (average particle diameter of 5 μm) produced by the atomization method.
“Au / Ni particles” in Comparative Example 5 are gold-plated nickel particles (average particle diameter of 5 μm) obtained by electroless gold plating of nickel particles.

  In Tables 1 to 3, “lauroyl” is dilauroyl peroxide. “BPO” is benzoyl peroxide.

In Tables 1 to 3, the types of thiol compounds are as follows.
PEMP: Pentaerythritol tetrakis (3-mercaptopropionate)
TEMPIC: Tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate TMMP: Trimethylolpropane tris (3-mercaptopropionate)
DPMP: dipentaerythritol hexakis (3-mercaptopropionate)
EHMP: 2-ethylhexyl-3-mercaptopropionate EGMP-4: Tetraethylene glycol bis (3-mercaptopropionate)
All of the above thiol compounds are manufactured by SC Organic Chemical Co., Ltd.

  In Examples 1 to 20, the insulating adhesive layer contains a thiol compound, and the conductive particle-containing layer contains conductive particles having Cu on the surface, thereby maintaining storage stability and a very low temperature of 110 ° C. It was confirmed that the connection reliability when connecting was compatible. Also, the adhesive strength was excellent.

In a temperature region such as 110 ° C., the curability is usually poor and the connection reliability is lowered. Even when a thiol compound is used, even if connection reliability when connected at 130 ° C. can be satisfied, it is difficult to satisfy connection reliability when connected at a lower temperature of 110 ° C.
The anisotropic conductive film of the present invention contains a thiol compound and conductive particles having Cu on the surface. Thus, it is thought that the connection reliability at the time of connecting at low temperature of 110 degreeC is satisfied by using together with the thiol compound and using the electroconductive particle which has Cu on the surface. However, when the thiol compound and the conductive particles having Cu on the surface are simply used together, the storage stability is lowered. This is considered to be because curing proceeds during storage due to high curability. Therefore, as in the present invention, the thiol compound is contained only in the insulating adhesive layer, and the conductive particle-containing layer contains conductive particles having Cu on the surface, so that the thiol compound and Cu are surfaced only at the time of connection. The conductive particles in contact with each other come into contact with each other, and both storage stability and connection reliability when connected at a very low temperature of 110 ° C. can be achieved.

When the content of the thiol compound in the insulating adhesive layer was 2% by mass to 7% by mass, all of connection reliability, adhesive strength, and storage stability were excellent (for example, Example 3). And 4).
As the curing agent, dilauroyl peroxide was superior to benzoyl peroxide in all of connection reliability, adhesive strength, and storage stability (for example, Examples 3 and 10).
Even if the average particle diameter of the conductive particles was varied within the range of 3 μm to 10 μm, there was almost no effect.
When the content of the conductive particles in the conductive particle-containing layer was 2% by mass to 30% by mass, all of connection reliability, adhesive strength, and storage stability were excellent (for example, implementation) Examples 12 and 19).

When the thiol compound was not contained, the reactivity was insufficient (for example, Comparative Example 1).
When the thiol compound was contained in both the conductive particle-containing layer and the insulating adhesive layer, the storage stability was insufficient (for example, Comparative Example 2).
When the thiol compound was contained only in the conductive particle-containing layer, the reactivity and storage stability were insufficient (for example, Comparative Example 3).
In the case of particles (for example, Ni particles, Au / Ni particles) other than the conductive particles having Cu on the surface as the conductive particles, the reactivity was insufficient (for example, Comparative Examples 4 and 5).

  Since the anisotropic conductive film of the present invention is excellent in storage stability and connection reliability when connected at low temperature, it is suitable for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component at a low temperature. Can be used.

Claims (5)

An anisotropic conductive film for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component,
A conductive particle-containing layer containing conductive particles, a film-forming resin, a curable resin, and a curing agent;
An insulating adhesive layer containing a film-forming resin, a curable resin, and a curing agent;
Only the insulating adhesive layer contains a thiol compound,
An anisotropic conductive film, wherein the conductive particles have Cu on the surface.   The anisotropic conductive film according to claim 1, wherein the content of the thiol compound in the insulating adhesive layer is 0.25% by mass to 15% by mass.   The anisotropic conductive film according to claim 1, wherein the conductive particles are at least one of Cu particles and Cu-coated resin particles. A method of connecting anisotropically conductively connecting a terminal of a substrate 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 3 on a terminal of the substrate;
A second disposing step of disposing the electronic component on the anisotropic conductive film such that a terminal of the electronic component is in contact with the anisotropic conductive film;
And a heating and pressing step of heating and pressing the electronic component with a heating and pressing member. A substrate having a terminal; an electronic component having a terminal; and an anisotropic conductive film that is interposed between the substrate and the electronic component and electrically connects the terminal of the substrate and the terminal of the electronic component. A cured product,
The joined body, wherein the anisotropic conductive film is the anisotropic conductive film according to claim 1.