JP6142612B2 - Anisotropic conductive film - Google Patents

Description

  The present invention provides an anisotropic conductive film for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component, a manufacturing method of a connection structure using the anisotropic conductive film, and a manufacturing method thereof. Connection structure.

  When electrically connecting electronic components such as IC chips and liquid crystal panels to a substrate, anisotropic conductive films are widely used. As such anisotropic conductive films, film forming components, epoxy-based curing components, A film in which an imidazole-based latent curing agent and conductive particles are uniformly mixed and formed on a base film is widely used (Patent Document 1). Such an anisotropic conductive film is usually stored wound on a reel in consideration of convenience during use.

JP 2006-252980 A

  By the way, the surface of a substrate or electronic component to be anisotropically conductively connected with such an anisotropic conductive film is contaminated with a cyclic silicone oligomer present as an impurity in a silicone sheet used during thermocompression bonding. There is a case. When anisotropic conductive connection is performed by thermocompression bonding in the presence of such contamination, conduction reliability may be reduced at the crimping interface during thermocompression bonding or subsequent high temperature and high humidity reliability tests. “Float” may occur. For this reason, the surface of a substrate or an electronic component to be anisotropically connected is cleaned by a technique such as solvent cleaning or plasma cleaning.

  However, depending on the state of contamination of the substrate and electronic components, the normal cleaning process may not be sufficient. In such a case, “floating” at the anisotropic conductive connection interface using the anisotropic conductive film. Increased risk of occurrence of inevitability. For this reason, there is a demand for an anisotropic conductive film that does not cause “floating” even when a substrate or electronic component that is not sufficiently cleaned by a normal cleaning process is used. In addition, the anisotropic conductive film that is wound and stored on a reel may be difficult to peel off from the base film or may be blocked from being peeled off from the base film. There is also a need for an anisotropic conductive film that can be easily peeled off and blocking is also suppressed.

  The present invention is intended to solve the conventional problems, and is applied to anisotropic conductive connection for anisotropic conductive film for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component. It is an object of the present invention to prevent “floating” from occurring at the same time, and to easily peel off from a base film when wound on a reel, and to suppress blocking.

  The inventor comprises an anisotropic conductive film composed of two layers, an anisotropic conductive layer and an insulating resin layer, and by setting the residual solvent amount in the anisotropic conductive layer within a predetermined range, The inventors have found that the above object can be achieved and have completed the present invention.

That is, the present invention is an anisotropic conductive film for anisotropic conductive connection between the terminal of the substrate and the terminal of the electronic component,
It has a two-layer structure in which an anisotropic conductive layer containing a film forming component, a polymerization component, a polymerization initiator and conductive particles and an insulating resin layer containing a film forming component are laminated,
The residual solvent amount in the anisotropic conductive layer is 2 to 8% by mass,
Provided is an anisotropic conductive film in which the polymerization initiator is substantially unaffected by the residual solvent.

  Moreover, this invention is a manufacturing method of the connection structure by which the terminal of the board | substrate and the terminal of the electronic component were anisotropically conductive-connected by the anisotropic conductive film, Comprising: The following processes (A)-(C) The manufacturing method which has, and the connection structure manufactured by the manufacturing method are provided.

<Process (A)>
Temporary sticking step of temporarily sticking the above-mentioned anisotropic conductive film of the present invention on the terminal of the substrate from the anisotropic conductive layer side;
<Process (B)>
A placing step of placing the electronic component on the temporarily attached anisotropic conductive film so that the terminal faces the terminal of the substrate; and <Step (C)>
A connecting step of obtaining a connection structure by anisotropically connecting the terminals of the substrate and the terminals of the electronic component by heating and pressing the placed electronic component with a heating pressing member.

  The anisotropic conductive film of the present invention comprises an anisotropic conductive layer containing a film forming component, a polymerization component, a polymerization initiator, and conductive particles, and an insulating resin layer containing a film forming component. It has a layer structure, the amount of residual solvent in the anisotropic conductive layer is adjusted to 2 to 8% by mass, and a polymerization initiator that does not substantially affect the polymerization initiation characteristics by the residual solvent is used. It is what. Therefore, the anisotropic conductive film of the present invention does not generate “float” when applied to anisotropic conductive connection, and is easily peeled off from the base film when wound on a reel, and blocking is also suppressed. It will be a thing.

  The anisotropic conductive film of the present invention is for anisotropically conductively connecting a terminal of a substrate and a terminal of an electronic component, and contains a film forming component, a polymerization component, a polymerization initiator, and conductive particles. It has a two-layer structure in which an anisotropic conductive layer and an insulating resin layer containing a film-forming component are laminated. Furthermore, the amount of residual solvent in the anisotropic conductive layer is adjusted to 2 to 8% by mass, and a polymerization initiator that does not substantially affect the polymerization initiation characteristics by the residual solvent is used. .

<Anisotropic conductive layer>
As described above, the residual solvent amount in the anisotropic conductive layer is adjusted to 2 to 8% by mass, preferably more than 5% to 8% by mass. For this reason, when a substrate or electronic component is bonded with an anisotropic conductive film, contaminants such as cyclic silicone oligomers on the surface of the substrate or electronic component on the side in contact with the anisotropic conductive layer should be excluded from the surface. Can do. Although the mechanism of exclusion is not clear, contaminants such as cyclic silicone oligomers are washed away from the surface by the residual solvent contained in a relatively large amount or taken into the anisotropic conductive film and further diffused to the outside. It is speculated that it has been excluded.

  If the amount of residual solvent is small, there is a concern that the effect of eliminating contaminants such as cyclic silicone oligomers will be insufficient, and if the amount is large, the peelability of the base film from the anisotropic conductive film is reduced, and the anisotropic conductive film. However, when the amount of residual solvent is 2 to 8% by mass, such a concern does not occur.

  In order to adjust the residual solvent amount in the anisotropic conductive layer to 2 to 8% by mass, the type and amount of the solvent used for the composition for forming the anisotropic conductive layer, the coating conditions when forming the anisotropic conductive layer, This can be done by adjusting the drying conditions. For example, with respect to the drying time, the amount of residual solvent can be increased if the time is short, and the amount of residual solvent can be decreased if the time is long.

  Here, the residual solvent can be appropriately selected from known solvents in consideration of dissolving power, boiling point, and the like according to the type of film forming component and polymerization component to be used. Preferred solvents include propylene glycol monomethyl ether acetate, polyethylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl ethyl ketone and the like. Among them, propylene glycol monomethyl ether from the viewpoint of preventing deterioration in workability when applying the composition for forming an anisotropic conductive layer (for example, problems caused by excessive drying of the coating film) and obtaining good film properties. Acetate can be preferably used.

(Film forming component)
As the film forming component used in the anisotropic conductive layer of the anisotropic conductive film of the present invention, among the film forming components used in the conventional anisotropic conductive film, the application target of the anisotropic conductive film And the compatibility with cellulose ester derivatives can be selected as appropriate. For example, phenoxy resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, and the like can be given. Two or more of these may be used in combination. Among these, a phenoxy resin can be preferably employed in terms of film formability, processability, and connection reliability.

  The content of the film-forming component in the anisotropic conductive layer is preferably 15 to 55% by mass, more preferably 30 to 40% by mass on a mass basis in order to maintain good film strength and anisotropic conductivity. It is.

(Polymerization component)
As the polymerization component used in the anisotropic conductive layer of the anisotropic conductive film of the present invention, the application target of the anisotropic conductive film or polymerized from the polymerization components used in the conventional anisotropic conductive film It can be appropriately selected in consideration of compatibility with the polymerization component. When the polymerization initiator is a radical polymerization initiator, a radical polymerizable acrylic monomer or oligomer can be preferably used. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) pyr acrylate, isobutyl (meth) acrylate, phosphoric acid group-containing (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, dimethyloltricyclodecane di (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2- Bis [4-((meth) acryloxymethoxy) phenyl] propane, 2,2-bis [4-((meth) acryloxyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meta Acry Chromatography, tris (acryloxyethyl) isocyanurate, urethane (meth) acrylate, epoxy (meth) acrylate. Two or more of these may be used in combination. Here, “(meth) acrylate” includes both acrylate and methacrylate.

  In addition, when the polymerization initiator is a cationic polymerization initiator, an epoxy compound or an oxetane compound can be preferably used.

Preferred examples of the epoxy compound include compounds, oligomers, and polymers having one or more epoxy groups in the molecule. These may be liquid or solid. Specifically, bisphenol A, bisphenol F, bisphenol S, hexahydrobisphenol A, tetramethylbisphenol A, diaryl bisphenol A, hydroquinone, catechol, resorcin, cresol, tetrabromobisphenol A, trihydroxybiphenyl, benzophenone, bisresorcinol, Glycidyl ether obtained by reacting polychlorophenol and epichlorohydrin such as bisphenol hexafluoroacetone, tetramethylbisphenol A, tetramethylbisphenol F, tris (hydroxyphenyl) methane, bixylenol, phenol novolak, cresol novolak, or glycerin, Neopentyl glycol, ethylene glycol, propylene glycol, tylene glycol Lumpur, hexylene glycol, polyethylene glycol, polyglycidyl ethers obtained by reacting an aliphatic polyhydric alcohol and epichlorohydrin such as polypropylene glycol;
Glycidyl ether ester obtained by reacting hydroxycarboxylic acid such as p-oxybenzoic acid and β-oxynaphthoic acid with epichlorohydrin, or phthalic acid, methylphthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydro Polyglycidyl esters obtained from polycarboxylic acids such as phthalic acid, endomethylenetetrahydrophthalic acid, endomethylenehexahydrophthalic acid, trimellitic acid, polymerized fatty acids;
Glycidyl aminoglycidyl ether obtained from aminophenol, aminoalkylphenol;
Glycidylaminoglycidyl ester obtained from aminobenzoic acid;
Glycidylamine obtained from aniline, toluidine, tribromoaniline, xylylenediamine, diaminocyclohexane, bisaminomethylcyclohexane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, etc .;
Known epoxy resins such as epoxidized polyolefins can be mentioned. In addition, alicyclic epoxy compounds such as 3,4-epoxycyclohexenylmethyl-3'4'-epoxycyclohexenecarboxylate can also be used.

  Examples of the oxetane compound include bis (3-ethyl-3-oxetanylmethyl) ether, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene. 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3-oxetanyl)] methyl ester, 3-ethyl-3- (Phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, oxetanylsilsesquioxane, phenol And novolak oxetane.

  The content of the polymerization component in the anisotropic conductive layer is preferably 15 to 65% by mass, more preferably 30 to 50% by mass in order to keep the film strength and anisotropic conductivity favorable. .

(Polymerization initiator)
As the polymerization initiator, it can be used by appropriately selecting from known polymerization initiators according to the kind of the polymerization component, but the polymerization initiator is not substantially affected by the residual solvent. There is a need to. This is because if the polymerization initiation characteristics are affected by the residual solvent, it is difficult to realize the intended polymerization reaction. For example, in the case of an imidazole-based latent curing agent which is an example of an anionic polymerization initiator, the microcapsule may be attacked by the residual solvent, in which case the potential is lowered, and as a result, the intended polymerization is performed. The reaction cannot be realized, and the storage stability is also lowered. Here, “substantially” means that the polymerization initiation characteristics are not significantly deviated from the scope of the present invention as long as the effects of the present invention can be obtained, even if the polymerization initiation characteristics are slightly affected by the residual solvent. .

  In the above constraints, when the polymerization component is a radical polymerizable acrylic monomer or oligomer, a polymerization initiator that generates free radicals by heat or light can be preferably used. And azo compounds. Among these, organic peroxides can be preferably used. Specific examples of the organic peroxide include benzoyl peroxide, tertiary butyl peroxide, di-2-ethylhexyl peroxydicarbonate, dilauroyl peroxide, 1,1-di (t-butylperoxy) cyclohexane, and the like. Is mentioned. As the azo compound, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile) (V-65), 2,2 ′ -Azobisisobutyronitrile (AIBN), 2,2'-azobis (2-methylbutyronitrile), 1,1-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis [2-methyl -N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide], dimethyl 2,2′-azobis (2-methoxypropionate) and the like. In addition, alkylphenone, benzoin, benzophenone, dicarbonyl compound, thioxanthone, acylphosphine oxide, derivatives thereof and the like can also be used as a polymerization initiator.

  When the polymerization component is an epoxy compound or an oxetane compound, a cationic polymerization initiator that initiates polymerization by the action of light or heat, preferably by the action of heat, can be preferably used. As such cationic polymerization initiators, known ones can be used, for example, aryldiazonium salt polymerization initiators, aryliodonium salt polymerization initiators, arylsulfonium salt polymerization initiators, allene ions. A complex polymerization initiator, a chelate polymerization initiator of a metal (for example, aluminum, titanium, zinc, tin, etc.) and an acetoacetate ester or a diketone can be used. In particular, it is preferable to use an arylsulfonium salt polymerization initiator from the viewpoint of excellent reactivity at low temperatures and a long pot life.

  Specific examples of commercially available cationic polymerization initiators that can be used in the present invention include, for example, aryldiazonium salts [for example, PP-33 (manufactured by ADEKA)], aryliodonium salts, arylsulfonium salts [for example, , FC-509, FC-540 (manufactured by 3M), UVE1014 (manufactured by GE), UVI-6974, UVI-6970, UVI-6990, UVI-6950 (manufactured by Union Carbide), SP-170 , SP-150, CP-66, CP-77, etc. (manufactured by ADEKA Corporation)], SI-60L, SI-80L, SI-100L, SI-110L (manufactured by Sanshin Chemical Industry Co., Ltd.), Allen -Ion complex [for example, CG-24-61 (made by Ciba-Geigy)] is mentioned.

  The content of these polymerization initiators in the anisotropic conductive layer is preferably based on 100 parts by mass of the polymerization component in order to improve the curing rate of the anisotropic conductive layer and suppress the decrease in the particle capture rate. It is 1-20 mass parts, More preferably, it is 3-10 mass parts.

(Conductive particles)
As the conductive particles contained in the anisotropic conductive layer of the anisotropic conductive film of the present invention, among the known conductive particles applied to anisotropic conductive connection, the intended use of the anisotropic conductive film It can be appropriately selected and used depending on. Examples of such conductive particles include metal particles and metal-coated resin particles. Examples of the metal particles include nickel particles, cobalt particles, silver particles, copper particles, gold particles, and palladium particles. As the metal-coated resin particles, the surface of core resin particles such as styrene-divinylbenzene copolymer particles, benzoguanamine resin particles, crosslinked polystyrene resin particles, acrylic resin particles, styrene-silica composite resin particles, nickel, copper, gold, And those coated with a metal such as palladium. On the surface of these metal particles and metal-coated resin particles, a thin film of gold or palladium, or an insulating resin thin film that is torn during anisotropic conductive connection may be formed as necessary.

  The average particle diameter of the conductive particles is preferably 1 to 10 μm, more preferably 2 to 5 μm, in order to realize reliable anisotropic conductive connection according to the purpose of use of the anisotropic conductive film.

  The content of the conductive particles in the anisotropic conductive layer of the anisotropic conductive film is preferably on a mass basis in order to realize a reliable anisotropic conductive connection according to the purpose of use of the anisotropic conductive film. 5 to 50%, more preferably 10 to 35%.

(Silane coupling agent)
The anisotropic conductive layer of the anisotropic conductive film of the present invention can contain a known silane coupling agent in order to improve adhesion to a particularly inorganic substrate such as a glass substrate. For example, an epoxy-based silane coupling agent, an acrylic silane coupling agent, a thiol-based silane coupling agent, an amine-based silane coupling agent, and the like are appropriately selected according to the purpose of use of the anisotropic conductive film. Can do.

  The content of the silane coupling agent in the anisotropic conductive layer of the anisotropic conductive film is set to 100 parts by mass in total of the film-forming component and the curing component in order to achieve a reliable addition effect of the silane coupling agent. On the other hand, Preferably it is 0.5-5 mass parts, More preferably, it is 1-3 mass parts.

(Other ingredients)
The anisotropic conductive layer of the anisotropic conductive film of this invention can contain various additives, such as a coloring agent, antioxidant, and a rust inhibitor, as needed.

(Thickness of anisotropic conductive layer)
The thickness of the anisotropic conductive layer is preferably 3 to 12 μm, more preferably 4 to 6 μm, in relation to the particle size of the conductive particles. Further, if the thickness of the anisotropic conductive layer is too thick, there is a tendency that the conductive particles are not easily captured between the terminals to be anisotropically conductive, and if it is too thin, the conductive particles in the anisotropic conductive film The dispersion state of the film tends to be non-uniform, and the applicability of the composition for forming an anisotropic conductive layer tends to decrease. Therefore, the total thickness of the anisotropic conductive film is preferably 10 to 40%, more preferably 20-30%.

<Insulating resin layer>
(Film forming component)
The insulating resin layer constituting the anisotropic conductive film of the present invention is a layer for ensuring the adhesion between the substrate to be connected and the electronic component and the insulation between the wirings, and contains at least a film forming component To do. The film forming component can be selected from those applicable to the anisotropic conductive layer. In addition to the film-forming component, the insulating resin layer includes, if necessary, the same polymerization component as the anisotropic conductive layer, a polymerization initiator, a silane coupling agent, a colorant, an antioxidant, a rust inhibitor, Various additives such as a solvent can be contained. Preferably, it is comprised from the same compounding component as an anisotropic conductive layer except not containing electroconductive particle.

  The amount of residual solvent in the insulating resin layer is preferably 0.1 to 10% by mass from the viewpoint of suppressing the occurrence of problems due to the protrusion of the resin component on the side surface of the reel when the anisotropic conductive film is wound around the reel. More preferably, it is 0.1-5 mass%.

(Insulating resin layer thickness)
The thickness of the insulating resin layer is preferably 5 to 25 μm, more preferably 10 from the viewpoint of filling a sufficient amount of insulating resin for adhesion between the substrate to be anisotropically conductive and the electronic component. ˜20 μm.

<Manufacture of anisotropic conductive film>
The anisotropic conductive film of the present invention can be produced as follows. First, an insulating resin layer forming composition is prepared by uniformly mixing a film-forming component and other components as necessary with a solvent such as propylene glycol monomethyl ether acetate by a known mixing method, Insulating resin layer by applying to a predetermined dry thickness (usually 8 to 20 μm) on the release sheet by a technique and drying in a drying oven adjusted to 60 to 80 ° C. for 2 to 8 minutes Form. Next, the above-described film-forming component, polymerization component, polymerization initiator, conductive particles, and other optional components such as a silane coupling agent, if necessary, together with a solvent such as propylene glycol monomethyl ether acetate are known. A composition for forming an anisotropic conductive layer is prepared by uniformly mixing by a mixing method, and this composition is coated on another release sheet by a known coating method to a predetermined dry thickness (usually a thickness of 4 to 10 μm). ) And drying in a drying oven adjusted to 60 to 80 ° C. to form an anisotropic conductive layer. The anisotropic conductive film of the present invention can be obtained by laminating the obtained anisotropic conductive layer and insulating resin layer by a known method and conditions.

  The anisotropic conductive film of the present invention thus obtained can be applied to substrates such as an ITO glass substrate, a flexible substrate, a rigid substrate, an IC module, and a mother board, and an electronic device such as an IC chip, a TAB tape, a liquid crystal panel, and various substrates. This can be preferably applied when manufacturing a connection structure by anisotropically connecting parts. The manufacturing method of the connection structure of this invention is demonstrated below.

<Method for manufacturing connection structure>
The method for manufacturing a connection structure of the present invention is a method for manufacturing a connection structure in which a terminal of a substrate and a terminal of an electronic component are anisotropically conductively connected by an anisotropic conductive film, and includes the following step (A): ~ (C).

(Temporary sticking step of step (A))
First, the anisotropic conductive film of the present invention is temporarily attached on the terminal of the substrate as described above from the anisotropic conductive layer side. The temporarily pasting technique and conditions can be appropriately selected from known techniques and conditions. Usually, temporary sticking is carried out by heating and pressurizing to such an extent that an anisotropic conductive film does not fully cure.

(Placement step of step (B))
Next, the electronic component is placed on the temporarily attached anisotropic conductive film so that the terminal faces the terminal of the substrate. As a mounting method, a known method can be employed. Usually, a board | substrate and an electronic component are temporarily fixed by heat-pressing so that an anisotropic conductive film may not fully cure.

(Connection process of process (C))
A connection structure in which the terminals of the substrate and the terminals of the electronic component are anisotropically conductively connected by heating and pressing the electronic component placed on the substrate through the heat pressing member through the placing step of the step (B). Get the body. The connection structure thus obtained is also part of the present invention. Here, as a method for heating and pressing, it can be performed using a heating and pressing apparatus conventionally used in anisotropic conductive connection. Moreover, a heating condition and a pressing condition can also be appropriately set according to the type of material used for the anisotropic conductive film.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

Reference Example 1 (Preparation of composition for forming anisotropic conductive layer)
40 parts by mass of a phenoxy resin (YP50, manufactured by Nippon Steel Chemical Co., Ltd.) as a film forming component, 40 parts by mass of a bisphenol A type liquid epoxy resin (EP828, Japan Epoxy Resin Co., Ltd.) as a polymerization component, and cationic polymerization As an initiator, 5 parts by mass of an arylsulfonium salt compound (SI-60L, Sanshin Chemical Industry Co., Ltd.) and conductive particles (Ni-plated resin core with an average particle size of 3 μm, manufactured by Sekisui Chemical Co., Ltd.) 40 masses Part and 85 parts by mass of propylene glycol monomethyl ether acetate (PMA) as a solvent were uniformly mixed using a mixer to obtain a composition for forming an anisotropic conductive layer of an anisotropic conductive film.

Reference Example 2 (Preparation of insulating resin layer forming composition)
40 parts by mass of a phenoxy resin (YP50, manufactured by Nippon Steel Chemical Co., Ltd.) as a film forming component, 40 parts by mass of a bisphenol A type liquid epoxy resin (EP828, Japan Epoxy Resin Co., Ltd.) as a polymerization component, and cationic polymerization Mix 5 parts by mass of an arylsulfonium salt compound (SI-60L, Sanshin Chemical Industry Co., Ltd.) as an initiator and 85 parts by mass of propylene glycol monomethyl ether acetate (PMA) as a solvent using a mixer. Thus, an insulating resin layer forming composition for an anisotropic conductive film was obtained.

Reference Example 3 (Creation of anisotropic conductive layer)
Using a bar coater, the anisotropic conductive layer forming composition obtained in Reference Example 1 is a 25 μm-thick base film (a polyethylene terephthalate film subjected to a release treatment) so as to have the dry thickness and residual solvent amount shown in Table 1. An anisotropic conductive layer was obtained by applying to an oven and drying in an oven at 70 ° C. The thickness of the anisotropic conductive layer is adjusted by adjusting the gap of the bar coater at the time of coating, and the residual solvent amount is adjusted by changing the drying time within the constraint of a maximum of 6 minutes. It was.

The residual solvent amount was measured by peeling the obtained anisotropic conductive layer from the base film, measuring the weight [W ₀ ] of the single anisotropic conductive layer, and then measuring the anisotropic conductive layer at 135 ° C. After removing the volatile components by putting them in the oven for 5 minutes, the weight [W ₁ ] was measured again and calculated according to the following formula.

Reference example 4 (creation of an insulating resin layer)
Using a bar coater, the composition for forming an insulating resin layer obtained in Reference Example 2 was applied to a 50 μm-thick base film (peeled polyethylene terephthalate film) so as to have the dry thickness and residual solvent amount shown in Table 1. The insulating resin layer was obtained by applying and drying. In addition, each adjustment of the thickness of an insulating resin layer and the amount of residual solvents was performed similarly to the anisotropic conductive layer.

Examples 1-5, Comparative Examples 1-4 (creation of anisotropic conductive film)
The anisotropic conductive layer and the insulating resin layer shown in Table 1 were bonded together using a roll laminator at a temperature of 45 ° C. and a pressure of 0.2 MPa (air pressure). By removing the film (peeled PET film), an anisotropic conductive film having a base film disposed on the insulating resin layer side was prepared.

(Evaluation)
About the anisotropic conductive films of the obtained Examples and Comparative Examples, each item of “crimp appearance”, “remaining amount of contaminants”, “base film peelability”, and “blocking characteristics” at the time of reel winding Testing and evaluation were performed as described below. The obtained results are shown in Table 1.

"Crimping appearance"
A glass substrate for a liquid crystal panel from which surface contaminants have been removed with acetone is placed on a hot plate set at 80 ° C. from the back side, and a 400 μm thick silicone rubber sheet (HC−) is placed on the front ITO wiring surface. 30A, Shin-Etsu Chemical Co., Ltd.) was stacked and pressed with a hand roller for 60 seconds. On the surface of this glass substrate, an anisotropic conductive film was temporarily attached from the side of the anisotropic conductive layer, and further an IC chip for flip chip connection (1.8 mm × 2.0 mm × 0. 5 mm thickness) was placed, and thermocompression bonding was performed with a flip chip bonder (TBX, Panasonic Factory Solution Co., Ltd.) under the conditions of a pressure bonding temperature of 170 ° C., a pressure bonding pressure of 125 N / IC, and a pressure bonding time of 5 seconds. The “floating” of the interface between the thermocompression bonded IC chip and the glass substrate was observed and evaluated according to the following criteria.

Rank Evaluation criteria ○: When “floating” is not observed at all Δ: When “floating” is observed only in an area of less than 1% of the total area of the anisotropic conductive film side surface of the IC chip ×: IC When “floating” is observed in an area of 1% or more of the total area of the chip's anisotropic conductive film side surface

"Residual amount of pollutants"
The IC chip on the glass substrate on which the appearance of the crimping appearance was tested was peeled off with a die shear tester (Dage 2400, manufactured by Daisy), and 5 μl of n-hexane was applied from the microsyringe to the peeling surface of the IC chip. The n-hexane was recovered. The collected n-hexane was hung on a plate-like support and dried. After completion of drying, the residue remaining on the support is analyzed using an FT-IR apparatus (Part No. FT / IR-4100, manufactured by JASCO Corporation), and the absorption wavelength peak (specific peak) peculiar to the cyclic silicone oligomer as a contaminant. Whether or not (800 cm ⁻¹ , 1260 cm ⁻¹ ) was observed was determined and evaluated according to the following criteria.

Rank Evaluation criteria ◎: When no peak is observed ○: When the detected intensity of the specific peak with respect to the internal standard peak (styrene) is less than 5% ×: The detected intensity of the specific peak with respect to the internal standard peak (styrene) is 5% If it is above

"Base film peelability"
The anisotropic conductive film was cut into a width of 5 cm, and the peel force between the anisotropic conductive film and the base film (peeled PET film) was measured using a tensile tester (Tensilon, Orientec Co., Ltd.). It is desirable that it is 0.1N / 5cm or less practically.

"Blocking characteristics"
The anisotropic conductive film was slit to a width of 1.5 mm, and wound about 100 m on a plastic reel to produce a reel product having a width of 1.5 mm × 100 m. After the central axis is passed through the center of the reel product and the reel product is fixed so as not to rotate around the central axis, a 50 g weight is attached to the outermost anisotropic conductive film, Left in the room for 3 hours. After leaving, the anisotropic conductive film was pulled out from the reel product, checked for the presence of blocking, and evaluated according to the following criteria.

Rank Evaluation criteria ○: When blocking does not occur △: When blocking less than 1 m in length occurs ×: When blocking of 1 m or more in length occurs

(Discussion)
The anisotropic conductive films of Examples 1 to 5 showed good results for each evaluation item of “crimp appearance”, “residual amount of contaminants”, “base film peelability”, and “blocking characteristics”. On the other hand, since the anisotropic conductive film of Comparative Example 1 has a single layer and a thick anisotropic conductive layer with a large amount of residual solvent, the evaluation results of “base film peelability” and “blocking characteristic” are examples. It was inferior compared. In the case of the anisotropic conductive films of Comparative Examples 2 and 3, since the amount of residual solvent in the anisotropic conductive layer is small, the evaluation results of “crimped appearance” and “residual amount of contaminants” are inferior to those of Examples. It was. In the case of the anisotropic conductive film of Comparative Example 4, although the amount of residual solvent in the insulating resin layer is large, the amount of residual solvent in the anisotropic conductive layer in contact with the glass substrate is small, so that the same as in Comparative Examples 2 and 3 In addition, the evaluation results of “crimp appearance” and “remaining amount of contaminants” were inferior to those of the examples.

  The anisotropic conductive film of the present invention does not generate “float” when applied to anisotropic conductive connection, and is easily peeled off from the base film even when wound on a reel, and blocking is also suppressed. Therefore, the anisotropic conductive film of the present invention is useful for anisotropic conductive connection between various substrates and electronic components.

Claims (10)

An anisotropic conductive film for anisotropic conductive connection between a terminal of a substrate and a terminal of an electronic component,
It has a two-layer structure in which an anisotropic conductive layer containing a film forming component, a polymerization component, a polymerization initiator and conductive particles and an insulating resin layer containing a film forming component are laminated,
The amount of residual solvent in the anisotropic conductive layer is 2 % by mass or more and 8% by mass or less ,
ACF polymerization initiator is one that polymerization initiation properties of resources by the residual solvent is not affected. The anisotropic conductive film according to claim 1, wherein the residual solvent amount in said anisotropic conductive layer is larger 8 wt% or less than 5%. The thickness of the anisotropic conductive layer, an anisotropic conductive film according to claim 1 or 2, wherein 40% or less than 10% of the anisotropic conductive film. The anisotropic conductive film according to any one of claims 1 to 3, wherein the polymerization initiator is a cationic polymerization initiator. The anisotropic conductive film according to claim 1, wherein the amount of residual solvent in the insulating resin layer is 0.1 % by mass or more and 10 % by mass or less . The anisotropic conductive film according to claim 1, wherein the polymerization component is an epoxy compound. The anisotropic conductive film according to any one of the heavy synthetic fraction, claims 1 containing 65% or less than 15% by weight 6. The anisotropic conductive film according to any one of claims 1 to 7, wherein the content of the polymerization initiator is 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerization component. A method for manufacturing a connection structure in which a terminal of a substrate and a terminal of an electronic component are anisotropically conductively connected by an anisotropic conductive film, the following steps (A) to (C):
(A) Temporary sticking step of temporarily sticking the anisotropic conductive film according to any one of claims 1 to 8 on the terminal of the substrate from the anisotropic conductive layer side;
(B) a placing step of placing an electronic component on the temporarily attached anisotropic conductive film such that the terminal faces the terminal of the substrate; and (C) a heating pressing member for placing the electronic component The manufacturing method which has the connection process of obtaining the connection structure by making the terminal of a board | substrate and the terminal of an electronic component carry out anisotropic conductive connection by heating and pressing by. A bonded structure in which a terminal of a substrate and a terminal of an electronic component are anisotropically conductively connected by the anisotropic conductive film according to claim 1 .