JP6900741B2 - Growing method of anisotropic conductive film, connection structure and connection structure - Google Patents

Description

The present invention relates to an anisotropic conductive film, a connecting structure, and a method for manufacturing the connecting structure.

Conventionally, for example, in the connection between a liquid crystal display and a tape carrier package (TCP), the connection between a flexible printed circuit board (FPC) and TCP, or the connection between an FPC and a printed wiring board, conductive particles are dispersed in an adhesive film. An anisotropic conductive film is used. Also, when mounting a semiconductor silicon chip on a substrate, so-called chip-on-glass (COG), in which the semiconductor silicon chip is directly mounted on the substrate, is performed instead of the conventional wire bonding, and this is also anisotropic conduction. Film is used.

In recent years, with the development of electronic devices, the density of wiring and the sophistication of circuits have been increasing. As a result, a connection structure in which the distance between the connection electrodes is, for example, 15 μm or less is required, and the bump electrode of the connection member has also been reduced in area. In order to obtain a stable electrical connection in the connection of bump electrodes with a smaller area (bump connection), it is necessary that a sufficient number of conductive particles are interposed between the bump electrode and the circuit electrode on the substrate side. is there.

In response to such problems, for example, Patent Document 1 below discloses a circuit connection adhesive having a first adhesive layer and a second adhesive layer, and average particles are contained as conductive particles contained in the adhesive layer. It is described that conductive particles having a diameter of 1 to 7 μm can be applied. Further, Patent Document 2 below proposes to use an anisotropic conductive adhesive film having a two-layer structure, which is an adhesive layer containing no conductive fine particles on the side in contact with the circuit board. Further, in Patent Document 3 below, conductive particles are densely packed on a laminate provided with an adhesive layer on a biaxially stretchable film, and the average particle spacing between the conductive particles and the adjacent particles is set. An anisotropic conductive adhesive sheet obtained by biaxially stretching and holding the particles so as to have a predetermined distance and transferring the conductive particles to an adhesive sheet having a predetermined thickness has been proposed. Further, in Patent Document 4 below, a large number of conductive particles that are regularly arranged apart from each other, a polymer film that holds the conductive particles, and an adhesive layer formed on one side of the polymer film. An anisotropic conductive film has been proposed in which the surface of the polymer film opposite to the surface on which the adhesive layer is formed has adhesiveness.

Japanese Unexamined Patent Publication No. 2003-49152 Japanese Unexamined Patent Publication No. 6-45024 Japanese Patent No. 4822322 JP-A-2009-76431

However, in the method disclosed in Patent Documents 1 to 3, the conductive particles flow together with the flow of the adhesive layer during the production of the connection structure, so that the conductive particles aggregate between the bump electrodes or between the circuit electrodes, resulting in a short circuit. It could occur. Further, the distribution of the density of the conductive particles due to the flow of the conductive particles may cause not only a decrease in the insulating characteristics but also a variation in the connection resistance value. On the other hand, in the method disclosed in Patent Document 4, when the conductive particles are embedded in the polymer film so that a part of the conductive particles protrudes from both sides of the polymer film, there is a concern that the conductive particles are likely to fall off and the polymer. There is a concern that the conductive particles tend to aggregate during the production of the connection structure due to insufficient film strength of the film. On the other hand, the conductive particles are polymerized so that a part of the conductive particles protrudes only on one surface of the polymer film. When embedded in a film, there is a concern that the polymer film fused to the conductive particles may cause an increase in connection resistance or a variation in connection resistance value.

In the present invention, in connecting circuit members to each other, an heterogeneous conductive film capable of ensuring connection reliability between opposing electrodes and ensuring insulation between adjacent electrodes in the circuit member, and between opposing electrodes It is an object of the present invention to provide a connection structure and a method for manufacturing the connection structure, which can achieve both the connection reliability of the above and the insulation property between adjacent electrodes in a circuit member.

In order to solve the above problems, the present invention includes a first adhesive layer, an insulating film which is a film and has through holes extending in the thickness direction of the film, and a second adhesive layer in this order. The insulating film has conductive particles arranged in the through holes, and the thickness of the insulating film is 0.4 times or more and 1.0 times or less the particle size of the conductive particles, and penetrates the ^{insulating film per 1 mm 2.} the number and conductive particles of holes when the MN _H and MN _p respectively, MN _p is less than 0.9 MN _H or 1.0 MN _H, provides the anisotropic conductive film.

According to the anisotropic conductive film of the present invention, by having the above structure, the conductive particles can be regularly arranged while being separated from each other, the flow of the conductive particles is suppressed, the electrodes facing each other are adhered to each other, and electricity is obtained. The connection can be balanced at a high level. As a result, in the connection between the circuit members, it is possible to secure the connection reliability between the opposing electrodes and the insulation between the adjacent electrodes in the circuit member at the same time.

In the anisotropic conductive film according to the present invention, ^{the number of through holes per 1 mm 2} of the insulating film may be 5000 or more and 30,000 or less. An anisotropic conductive film having such an insulating film can contain conductive particles at a density corresponding to the number of through holes described above, ensuring connection reliability between opposing electrodes and adjoining adjacent electrodes in a circuit member. It is possible to more preferably balance the securing of the insulating property between the electrodes.

In the anisotropic conductive film according to the present invention, the ratio of the conductive particles existing apart from the other conductive particles in the conductive particles may be 97% or more.

Further, the average particle size of the conductive particles may be 2.5 μm or more and 6.0 μm or less.

Further, the thickness of the first adhesive layer may be 0.1 μm or more and 1.0 μm or less. Even when one of the circuit members to be connected is a circuit member having a bump electrode and the other is a circuit member having a circuit electrode (an electrode having no bump) corresponding to the bump electrode, the first having the above thickness. By arranging the isotropic conductive film so that the adhesive layer side of the above faces the circuit member side having the circuit electrode (electrode having no bump) corresponding to the bump electrode, it becomes easy to suppress the flow of the conductive particles. It becomes easy to secure the insulation between adjacent electrodes in the circuit member.

The present invention also comprises a first circuit member having a first electrode, a second circuit member having a second electrode corresponding to the first electrode, and a second circuit member having a first adhesive layer side. It is composed of a cured product of the isotropic conductive film according to the present invention, which is directed toward the side, and adheres the first circuit member and the second circuit member and electrically connects the first electrode and the second electrode. Provided is a connection structure including a connection portion.

In the above connection structure, since the circuit members are connected to each other by the cured product of the anisotropic conductive film according to the present invention, the connection reliability between the opposing electrodes and the insulation between the adjacent electrodes in the circuit member Can be compatible with.

In the above connection structure, even when the first electrode is a bump electrode and the second electrode is a circuit electrode corresponding to the bump electrode, the connection reliability between the opposing electrodes and the connection reliability in the circuit member It is possible to achieve both insulation between adjacent electrodes.

In particular, when the thickness of the first adhesive layer of the anisotropic conductive film according to the present invention is 0.1 μm or more and 1.0 μm or less, it becomes easy to suppress the flow of conductive particles, and the adjacent particles in the circuit member are adjacent to each other. It becomes easy to secure the insulation between matching electrodes.

The present invention also includes a first circuit member having a first electrode, a second circuit member having a second electrode corresponding to the first electrode, a first circuit member and a second circuit member. The insulating film is provided with a connecting portion for electrically connecting the first electrode and the second electrode, and the connecting portion is a film and has a through hole extending in the thickness direction of the film. Provided is a connection structure which is arranged in a hole and includes a conductive particle which is interposed between the first electrode and the second electrode and electrically connects the first electrode and the second electrode.

In the connection structure, the insulating film can sufficiently secure the insulating property between adjacent electrodes in the circuit member, and the conductive particles can sufficiently secure the connection reliability between the opposing electrodes. ..

In the above connection structure, even when the first electrode is a bump electrode and the second electrode is a circuit electrode corresponding to the bump electrode, the connection reliability between the opposing electrodes and the connection reliability in the circuit member It is possible to achieve both insulation between adjacent electrodes.

The present invention also relates to the anisotropic conductive film according to the present invention between a first circuit member having a first electrode and a second circuit member having a second electrode corresponding to the first electrode. Provided is a method for manufacturing a connection structure having a step of thermocompression bonding the first circuit member and the second circuit member by interposing the first adhesive layer side toward the second circuit member side.

According to the above method, it is possible to obtain a connection structure having both the connection reliability between the opposing electrodes and the insulating property between the adjacent electrodes in the circuit member.

In the above method, even when the first electrode is a bump electrode and the second electrode is a circuit electrode corresponding to the bump electrode, the connection reliability between the opposing electrodes and the adjacent electrode in the circuit member are adjacent to each other. It is possible to obtain a connection structure that has both insulating properties between electrodes.

In particular, when the thickness of the first adhesive layer of the anisotropic conductive film according to the present invention is 0.1 μm or more and 1.0 μm or less, it becomes easy to suppress the flow of conductive particles, and the adjacent particles in the circuit member are adjacent to each other. It becomes easy to secure the insulation between matching electrodes.

According to the present invention, in connecting circuit members to each other, an anisotropic conductive film capable of ensuring connection reliability between opposing electrodes and ensuring insulation between adjacent electrodes in the circuit member, and facing each other. It is possible to provide a connection structure and a method for manufacturing the connection structure, which can achieve both connection reliability between electrodes and insulation between adjacent electrodes in a circuit member.

It is a schematic cross-sectional view which shows one Embodiment of the anisotropic conductive film which concerns on this invention. It is an enlarged schematic view of the main part of the anisotropic conductive film shown in FIG. FIG. 2 is a cross-sectional view taken along the line II of FIG. It is a schematic cross-sectional view which shows the manufacturing process of the insulating film which has a through hole. It is a schematic cross-sectional view which shows the manufacturing process of the anisotropic conductive film which concerns on this invention. It is a schematic cross-sectional view which shows the subsequent process of FIG. It is a schematic cross-sectional view which shows one Embodiment of the connection structure which concerns on this invention. It is a schematic cross-sectional view which shows the manufacturing process of the connection structure shown in FIG. 7. It is a schematic cross-sectional view which shows the subsequent process of FIG.

Hereinafter, preferred embodiments of the anisotropic conductive film, the connecting structure, and the method for manufacturing the connecting structure according to the present invention will be described in detail with reference to the drawings.

[Structure of anisotropic conductive film]
The anisotropic conductive film according to the present embodiment includes a first adhesive layer, an insulating film which is a film and has through holes extending in the thickness direction of the film, and a second adhesive layer in this order. , Has conductive particles arranged in the through hole. This anisotropic conductive film includes an insulating film which is a film and has through holes extending in the thickness direction of the film and conductive particles arranged in the through holes, and the insulating film and the conductive particles and anisotropic conductivity. It may have a region containing an adhesive between both main surfaces of the film. The conditions of the first adhesive layer and the second adhesive layer in one embodiment of the anisotropic conductive film described below can be the conditions of the two regions containing the above-mentioned adhesive, and the first The condition of the thickness of the adhesive layer and the second adhesive layer can be read as the shortest distance between the main surface of the anisotropic conductive film and the insulating film or conductive particles.

FIG. 1 is a schematic cross-sectional view showing an embodiment of an anisotropic conductive film according to the present invention. The anisotropic conductive film 10 shown in FIG. 1 shows an anisotropic conductive film provided on the release film 12, and the anisotropic conductive film according to the present embodiment is composed of a laminate 11. In the laminated body 11, the first adhesive layer 22, the insulating film 20 which is a film and has through holes 21 extending in the thickness direction of the film, and the second adhesive layer 23 are laminated in this order. Therefore, the conductive particles P arranged in the through hole 21 are included. The laminate 11 has regions 13 and 15 in which the conductive particles P are not included in the cross section when cut in a plane perpendicular to the thickness direction of the insulating film 20, and regions 14 in which the conductive particles P are contained. doing.

The through holes 21 are filled with conductive particles P, and an adhesive may be filled between the conductive particles P and the wall surface surrounding the through holes 21 of the insulating film 20. In the present embodiment, the through hole 21 is filled with the adhesive constituting the second adhesive layer 23.

The laminate 11 shown in FIG. 1 may have through holes 21 in which all the through holes 21 are filled with the conductive particles P, but the conductive particles P are not filled. The through hole 21 not filled with the conductive particles P may be filled with an adhesive constituting the second adhesive layer 23.

The release film 12 is made of, for example, polyethylene terephthalate (PET), polyethylene, polypropylene, or the like. The release film 12 may contain an arbitrary filler. Further, the surface of the release film 12 may be subjected to a mold release treatment, a plasma treatment, or the like.

The first adhesive layer 22 and the second adhesive layer 23 can contain an adhesive component and a film-forming agent.

Examples of the adhesive component include a monomer (main agent) and a curing agent. As the monomer, a cationically polymerizable compound, an anionically polymerizable compound or a radically polymerizable compound can be used. Examples of the cationically polymerizable compound or the anionically polymerizable compound include epoxy compounds.

As the epoxy compound, the epoxy novolac derived from epichlorohydrin, a bisphenol type epoxy resin derived from a bisphenol compound such as bisphenol A, bisphenol F or bisphenol AD, epichlorohydrin, and a novolak resin such as phenol novolac or cresol novolac. As well as resins, various epoxy compounds having two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic can be used. The epoxy compound may be an oligomer.

As the radically polymerizable compound, a compound having a functional group that is polymerized by a radical can be used, and examples thereof include an acrylic compound such as (meth) acrylate, a maleimide compound, and a styrene derivative. The radically polymerizable compound can be used in either a monomer or an oligomer state, and the monomer and the oligomer may be mixed and used. That is, in the present specification, the monomer also includes an oligomer.

As the monomer, one type may be used alone, or two or more types may be used in combination.

When an epoxy compound is used, examples of the curing agent include imidazole type, hydrazide type, boron trifluoride-amine complex, sulfonium salt, amineimide, polyamine salt, dicyandiamide, acid anhydride and the like. It is preferable that these curing agents are coated with a polyurethane-based or polyester-based polymer substance and microencapsulated in terms of extending the pot life.

The curing agent used in combination with the epoxy compound is appropriately selected depending on the target connection temperature, connection time, storage stability, and the like. When the curing agent is a composition containing an epoxy compound and a curing agent from the viewpoint of high reactivity, the gel time is preferably within 10 seconds at a predetermined temperature, and from the viewpoint of storage stability, it is preferable. It is preferable that there is no difference in gel time from the composition after storage in a constant temperature bath at 40 ° C. for 10 days. From this point of view, the curing agent is preferably a sulfonium salt.

When an acrylic compound is used, examples of the curing agent include those that decompose by heating, such as a peroxide compound and an azo compound, to generate free radicals.

The curing agent used in combination with the acrylic compound is appropriately selected depending on the target connection temperature, connection time, storage stability, and the like. From the viewpoint of high reactivity and storage stability, the curing agent is preferably an organic peroxide or an azo compound having a half-life of 10 hours of 40 ° C. or higher and a half-life of 1 minute of 180 ° C. or lower, and has a half-life of 180 ° C. or higher. More preferably, an organic peroxide or an azo compound having a temperature of 60 ° C. or higher for 10 hours and a temperature of 170 ° C. or lower for a half-life of 1 minute is preferable.

As the curing agent, one type may be used alone, or two or more types may be used in combination. The first adhesive layer 22 and the second adhesive layer 23 may further contain a decomposition accelerator, an inhibitor, and the like.

The amount of the curing agent blended is the monomer and the film formation described later from the viewpoint of obtaining a sufficient reaction rate when the connection time is 10 seconds or less regardless of whether the monomer of the epoxy compound or the acrylic compound is used. It is preferably 0.1 part by mass or more and 40 parts by mass or less, and more preferably 1 part by mass or more and 35 parts by mass or less with respect to 100 parts by mass in total with the material. When the blending amount of the curing agent is 0.1 parts by mass or more, a sufficient reaction rate can be obtained, good adhesive strength and small connection resistance can be easily obtained, and when it is 40 parts by mass or less, the adhesive It becomes easy to prevent the flowability of the layer from decreasing and the connection resistance from increasing, and it becomes easy to secure the storage stability of the anisotropic conductive film.

The film-forming material is preferably a polymer containing the above-mentioned monomer and curing agent and having an action of facilitating the handling of a low-viscosity composition. By using the film forming material, it is possible to prevent the film from being easily torn, cracked or sticky, and it is possible to obtain an anisotropic conductive film that is easy to handle.

As the film forming material, a thermoplastic resin can be preferably used. For example, phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin, polyacrylic resin, polyester urethane resin and the like can be mentioned. These polymers may contain siloxane bonds or fluorine substituents. Among the above resins, it is preferable to use a phenoxy resin from the viewpoint of adhesive strength, compatibility, heat resistance, and mechanical strength.

The above-mentioned thermoplastic resin may be used alone or in combination of two or more.

The larger the molecular weight of the thermoplastic resin, the easier it is to obtain film formability, and the melt viscosity that affects the fluidity of the adhesive layer can be set in a wide range. The weight average molecular weight of the thermoplastic resin is preferably 5000 or more and 150,000 or less, and more preferably 10,000 or more and 80,000 or less. When the weight average molecular weight of the thermoplastic resin is 5000 or more, good film formability can be easily obtained, and when it is 150,000 or less, good compatibility with other components can be easily obtained.

In the present invention, the weight average molecular weight refers to a value measured by a gel permeation chromatograph (GPC) using a calibration curve using standard polystyrene according to the following conditions.
(Measurement condition)
Equipment: GPC-8020 manufactured by Tosoh Corporation
Detector: RI-8020 manufactured by Tosoh Corporation
Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Kasei Co., Ltd.
Sample concentration: 120 mg / 3 mL
Solvent: Tetrahydrofuran Injection volume: 60 μL
Pressure: 2.94 x 106 Pa (30 kgf / cm ² )
Flow rate: 1.00 mL / min

The blending amount of the film forming material is preferably 5% by mass or more and 80% by mass or less, and more preferably 15% by mass or more and 70% by mass or less, based on the total amount of the monomer, the curing agent and the film forming material. When the blending amount of the film forming material is 5% by mass or more, good film forming property is easily obtained, and when it is 80% by mass or less, the adhesive layer tends to show good fluidity.

Further, the first adhesive layer 22 and the second adhesive layer 23 are filled with a filler, a softening agent, an accelerator, an antiaging agent, a coloring agent, a flame retardant, a thixotropic agent, a coupling agent, and a phenol. It may further contain a resin, a melamine resin, isocyanates and the like. When the adhesive layer contains a filler, further improvement in connection reliability can be expected.

Examples of the insulating film 20 include a film obtained by curing a composition containing a monomer (main agent) and a curing agent, a film containing a polymer such as polyethylene terephthalate (PET), polyethylene, polypropylene, and polyimide.

A film obtained by curing a composition containing a monomer and a curing agent is preferably used because it is easy to form through holes.

Examples of the monomer include a cationically polymerizable compound, an anionically polymerizable compound, and a radically polymerizable compound.

Examples of the cationically polymerizable compound or the anionically polymerizable compound include epoxy compounds. As the epoxy compound, the epoxy novolac derived from epichlorohydrin, a bisphenol type epoxy resin derived from a bisphenol compound such as bisphenol A, bisphenol F or bisphenol AD, epichlorohydrin, and a novolak resin such as phenol novolac or cresol novolac. As well as resins, various epoxy compounds having two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic can be used. The epoxy compound may be an oligomer.

As the radically polymerizable compound, a compound having a functional group that is polymerized by a radical can be used, and examples thereof include an acrylic compound such as (meth) acrylate, a maleimide compound, and a styrene derivative. The radically polymerizable compound may be an oligomer.

As the monomer, one type may be used alone, or two or more types may be used in combination.

When an epoxy compound is used as the cationically polymerizable compound or the anionic polymerizable compound, examples of the curing agent include a photoacid generator that generates an acid by irradiation with ultraviolet rays, a photobase generator that generates a base by irradiation with ultraviolet rays, and the like. Be done. On the other hand, when a radically polymerizable compound is used, examples of the curing agent include a photoradical generator in which free radicals are generated by irradiation with ultraviolet rays.

Regardless of which curing agent is used, the type and blending amount of the curing agent are appropriately selected depending on the film formation temperature, drying time, and storage stability. From the viewpoint of reactivity, it is preferable that curing is completed at an ^{irradiation amount of 2000 mJ / mm 2} or less by ultraviolet rays having a wavelength of 365 nm at 25 ° C. Further, from the viewpoint of forming through holes, it is preferable to select the type and blending amount of the curing agent so that the curing is completed at an ^{irradiation amount of 2000 mJ / mm 2} or less by ultraviolet rays having a wavelength of 365 nm at 25 ° C.

The insulating film 20 further contains a filler, a softening agent, an accelerator, an antiaging agent, a coloring agent, a flame retardant, a mold release agent, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, an isocyanate, and the like. It may be contained. When a release agent is contained, the filling property of the conductive particles and the formation of through holes described later tend to be good.

It is preferable that the shape of the insulating film 20 does not easily change due to heating or pressurization during the manufacture of the connection structure. Further, it is preferable that the insulating film 20 is not easily broken during the production of the connection structure. From this point of view, the insulating film 20 preferably has an elastic modulus of 1 MPa or more at 150 ° C., and more preferably 10 MPa or more from the viewpoint of preventing deformation.

For the elastic modulus at 150 ° C., a 100 μm-thick insulating film having no through holes was prepared, and a dynamic viscoelastic device (for example, RSA-3 of TA Instruments Japan Co., Ltd.) was used. The value measured in the tension mode under the conditions of a heating rate of 5 ° C./min, a frequency of 1 Hz, and a strain of 0.1%.

^{The number of through holes per 1 mm 2 of the} insulating film 20 is preferably 5,000 or more and 30,000 or less, more preferably 6,000 or more and 29000 or less, and further preferably 8,000 or more and 25,000 or less. preferable. The anisotropic conductive film having such an insulating film 20 can contain conductive particles at a density corresponding to the number of through holes described above, ensuring connection reliability between opposing electrodes and adjoining the circuit member. It is possible to more preferably achieve both the assurance of the insulating property between the matching electrodes.

The thickness of the insulating film 20 is preferably 1.0 times or less the conductive particle size, and less than 1.0 times the conductive particle size, from the viewpoint of reducing the resistance when the first electrode and the second electrode are connected. More preferably.

Examples of the conductive particles P include metal particles such as gold, silver, nickel, copper, and solder, and conductive coated particles obtained by coating non-conductive particles such as carbon particles, glass, ceramics, and plastic with a conductive substance such as metal. Can be mentioned. Examples of the metal that coats the non-conductive particles include gold, silver, nickel, copper, solder, and the like, and may have a multilayer structure.

From the viewpoint of storage stability, the conductive particles preferably have a surface layer containing platinum group noble metals such as gold and silver, and more preferably have a surface layer containing gold. The surface layer containing precious metals may be provided on the surface of nickel.

Of the metal particles, the heat-melted metal particles such as solder and the conductive coated particles obtained by coating plastic or the like with a conductive substance such as metal are easily deformed by heating and pressurizing, so that they come into contact with the electrodes at the time of connection. As the area increases, the variation in thickness on the circuit member side can be absorbed, and the connection reliability can be further improved.

The conductive particles P may be provided with protrusions on the surface. In this case, it becomes easy to reduce the connection resistance.

The average particle size of the conductive particles P is preferably 2.5 μm or more and 6.0 μm or less. When the average particle size of the conductive particles is 2.5 μm or more, the visibility of the conductive particles at the time of crimping is improved, and it becomes easy to confirm the state of the conductive particles captured between the opposing circuits. When the average particle size of the conductive particles is 6.0 μm or less, it is easy to obtain good insulation characteristics even when connecting a circuit member having a high-definition circuit in which the distance between adjacent circuit electrodes is 15 μm or less. It becomes.

From the viewpoint of reducing the connection resistance between the opposing electrodes, the average particle size of the conductive particles is preferably 2.7 μm or more, and more preferably 3 μm or more. On the other hand, from the viewpoint of ensuring the insulating property between adjacent circuit electrodes, the average particle size of the conductive particles is preferably 5.5 μm or less, and more preferably 5 μm or less.

The average particle size of the conductive particles is obtained by measuring the particle size of 300 arbitrary conductive particles by observation using a scanning electron microscope (SEM) and taking the average value thereof. When the conductive particles are not spherical such as having protrusions, the particle size of the conductive particles is the diameter of a circle circumscribing the conductive particles in the SEM image.

In the anisotropic conductive film of the present embodiment, it is preferable that the conductive particles P are unevenly distributed on one surface side of both main surfaces of the laminated body 11. As shown in FIG. 1, when the conductive particles P are unevenly distributed on one side of the release film 12 of the laminated body 11, the shortest distance between the conductive particles P and one side is 0.1 μm or more 1 It may be 0.0 μm or less. By setting the shortest distance, that is, the thickness of the region 15 not including the conductive particles P within the above range, it is easy to suppress the flow of the conductive particles P during crimping while ensuring the adhesion to the circuit member. Therefore, the capturing performance of the conductive particles P can be improved.

In the present embodiment, the thickness of the first adhesive layer 22 may be 0.1 μm or more and 1.0 μm or less. By setting the thickness of the first adhesive layer 22 to 0.1 μm or more, good adhesion can be easily obtained when the anisotropic conductive film is attached to the circuit member, and by setting it to 1.0 μm or less, pressure bonding is performed. It becomes easy to suppress the flow of conductive particles at the time. Further, from the viewpoint of improving the trapping property of the conductive particles captured between the opposing electrodes of the circuit member to be connected, the thickness of the first adhesive layer 22 may be 0.8 μm or less, and may be 0.5 μm or less. It may be. In particular, when one of the circuit members to be connected is a circuit member having a bump electrode and the other is a circuit member having a circuit electrode (electrode having no bump) corresponding to the bump electrode, the first adhesive layer side is the first. The above effect can be obtained more effectively by interposing between the circuit members so as to face the second circuit member side.

The thickness of the second adhesive layer 23 can be appropriately set, and can be, for example, 12 μm or more and 30 μm or less. The thickness of the region 13 that does not contain the conductive particles P can be, for example, 10 μm or more and 28 μm or less. Further, when the thickness of the second adhesive layer 23 is 1.2 times or less the total height of the electrodes of each of the connecting circuit members, the trapping property of the conductive particles can be improved. It will be easy.

The second adhesive layer 23 can also have a multi-layer structure.

In the present embodiment, from the viewpoint of improving the catching property of the conductive particles, the ratio Da / Db of the thickness Da of the first adhesive layer 22 to the thickness Db of the second adhesive layer 23 is set to 0.1 / Db. It may be 10 to 10/10, or 0.5 / 10 to 5/10. From the same viewpoint, the ratio Dc / Dd of the thickness Dc of the region 15 not containing the conductive particles P to the thickness Dd of the region 13 not containing the conductive particles P is 0.05 / 10-8 /. It may be 10 or 0.25 / 10-4 / 10.

The thickness of the anisotropic conductive film may be, for example, 5 μm or more and 30 μm or less. In the present embodiment, the total thickness of the first adhesive layer 22, the thickness of the insulating film 20, and the thickness of the second adhesive layer 23, that is, the thickness of the laminated body is, for example, 5 μm or more and 30 μm or less. May be good.

The thickness of the anisotropic conductive film is preferably set to be 0 μm or more and 10 μm or less larger than the distance between the mounting surfaces of the circuit members in the connection structure when the circuit members are connected to each other. By setting the thickness of the anisotropic conductive film to be 0 μm or more larger than the above interval, it becomes easier to fill the space between the circuit members with the cured product of the anisotropic conductive film, causing peeling, and connection reliability after the moisture resistance test. It becomes easy to suppress the decrease of. On the other hand, by setting the thickness of the anisotropic conductive film to be 10 μm or less larger than the above interval, the fluidity of the resin when the circuit members are crimped to each other can be maintained, so that the resin between the opposing electrodes can be maintained. It becomes possible to achieve both the exclusion property and the filling property of the resin between adjacent electrodes at a high level, and it becomes easy to obtain an electrical connection between the opposing electrodes even after a reliability test such as a moisture resistance test. From these viewpoints, the thickness of the anisotropic conductive film is more preferably set to be 0.5 μm or more and 8.0 μm or less larger than the above interval, and is set to be 1.0 μm or more and 5.0 μm or less larger. It is more preferable to do so.

Regarding the thickness of the first adhesive layer 22, the thickness of the insulating film 20, and the thickness of the second adhesive layer 23, for example, ion milling is used to cut a cross section of the anisotropic conductive film, and then scanning. It can be observed and measured with a scanning electron microscope (SEM). Specifically, the anisotropic conductive film is fixed to a jig for sample processing / observation using a conductive carbon tape. Then, using ion milling, processing is performed from the second adhesive layer 23 side of the anisotropic conductive film, and the processed cross section is observed with a scanning electron microscope (SEM).

FIG. 2 is an enlarged schematic view of a main part of the anisotropic conductive film. The thickness T of the insulating film 20 is preferably 0.4 times or more and 1.0 times or less, and more preferably 0.4 times or more and less than 1.0 times the particle size D of the conductive particles P. For example, in a connection structure in which circuit members are connected to each other using an anisotropic conductive film, the conductive particles P interposed between the opposing electrodes are flattened and come into contact with the respective electrodes to ensure electrical connection. Will be done. When the thickness T of the insulating film 20 is 0.4 times or more the particle size D of the conductive particles, it is possible to suppress excessive deformation of the conductive particles when the circuit members are pressure-bonded to each other, and the conductive particles can be prevented from being excessively deformed. It becomes easy to suppress the flow and secure the insulation between the adjacent circuit electrodes. On the other hand, when the thickness T of the insulating film 20 is 1.0 times or less the particle size D of the conductive particles, it becomes easy to secure the electrical connection by the conductive particles. The thickness T of the insulating film 20 is 0.5 times or more the particle size D of the conductive particles from the viewpoint of achieving both the connection reliability between the opposing electrodes and the insulating property between the adjacent electrodes in the circuit member at a high level. It is preferably 0.8 times or less.

FIG. 3 is a cross-sectional view taken along the line II of FIG. The insulating film 20 shown in FIG. 3 is provided with a through hole 21 extending in the thickness direction thereof, and the wall surface surrounding the through hole 21 has a cylindrical shape. That is, the insulating film 20 is provided with a through hole having a circular cross-sectional shape when cut on a plane perpendicular to the thickness direction of the film.

The angle formed by the main surface of the insulating film 20 and the wall surface surrounding the through hole 21 can be 90 ° to 85 °, and 89 ° to 87 ° in terms of ease of creating the through hole. Can be done.

The diameter W of the through holes of the insulating film 20 is preferably 1.0 times or more and 1.2 times or less the particle size D of the conductive particles. In this case, since one conductive particle can be filled in one through hole, it becomes easy to secure the insulating property between adjacent electrodes in the circuit member. Further, there is an advantage that the conductive particles in the connecting structure can be easily observed, and the conductive particles captured between the opposing electrodes can be easily identified.

The insulating film 20 can be formed with through holes having a cross-sectional shape other than a circular shape. For example, through holes having a cross-sectional shape such as a square, a rhombus, or a hexagon may be provided. The shape of the through hole is arbitrary, and the size of the through hole is in a direction orthogonal to the axis of the through hole (that is, the thickness direction of the insulating film 20) when the conductive particles are moved in the through hole. The maximum movable distance is preferably 0 times or more and 0.2 times or less, and more preferably 0 times or more and 0.1 times or less of the particle size D of the conductive particles.

The insulating film 20 preferably has through holes that are regularly arranged. Examples of the arrangement pattern include a square arrangement and a hexagonal arrangement. From the viewpoint of increasing the number of through holes in order to support the connection of high-definition circuits, it is preferable to provide the through holes in a hexagonal arrangement pattern.

In the anisotropic conductive film of the present embodiment, the particle density of the conductive particles is preferably 5000 / mm ² or more 30000 / mm ² or less. By satisfying this condition, it is possible to more preferably secure the connection reliability between the opposing electrodes and the insulation between the adjacent electrodes in the circuit member.

In the anisotropic conductive film of the present embodiment, when the number of through holes and the number of conductive particles per ^{1 mm 2} _{of the insulating film 20 are MN H} and MN _p , respectively, MN _p is 0.9 _{MN H} or more. 0 mN _H may be less, and may be less 0.95MN _H or 1.0 MN _H.

In the anisotropic conductive film of the present embodiment, the ratio of the conductive particles existing apart from the other conductive particles in the conductive particles may be 97% or more, or 99% or more.

[Manufacturing method of insulating film having through holes]
The method for producing the above-mentioned insulating film 20 will be described. FIG. 4 is a schematic cross-sectional view showing a manufacturing process of an insulating film having through holes.

The manufacturing method of this embodiment is
Step 1 of preparing a laminate having an easy-adhesive film 30, a resin layer 31 provided on the easy-adhesive film 30, and a transfer resin layer 32 provided on the resin layer 31 ((a) in FIG. 4). When,
Step 2 ((b) of FIG. 4) in which the mold 40 having the regularly arranged convex pattern is pressed from the transfer resin layer 32 side of the laminate,
After the transfer resin layer 32 is cured, the mold 40 is peeled off to obtain an element in which the resin layer 31 and the insulating film 20 having the through holes 21 are provided on the easy-adhesion film 30 (FIG. 4 (FIG. 4). c)) and
To be equipped.

As the easy-adhesion film 30, for example, a film made of polyester such as polyethylene terephthalate (PET), polyethylene, polypropylene, or the like can be used. The easy-adhesion film 30 may contain an arbitrary filler. Further, it is preferable that the surface of the easy-adhesion film 30 is subjected to an easy-adhesion treatment or the like.

The resin layer 31 is formed of, for example, polyester resin, polypropylene resin, polyethylene resin, polycarbonate resin, polyimide resin, epoxy resin, phenoxy resin, polyester urethane resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl acetate resin, polystyrene resin and the like. be able to. Two or more of the above resins can be used in combination. From the viewpoint of solubility in an organic solvent, it is preferable to use polyvinyl butyral resin.

The resin layer 31 can be produced by applying a resin paste containing the above resin onto the easy-adhesion film 30. The resin paste can contain a solvent such as an organic solvent, and the thickness of the resin paste can be appropriately adjusted depending on the ratio of the solvent. Examples of the organic solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, toluene, tetrahydrofuran, acetonitrile and the like. One of these may be used alone, or two or more thereof may be used in combination.

As a method for applying the resin paste, a known method can be used. For example, spin coating method, roller coating method, bar coating method, dip coating method, micro gravure coating method, curtain coating method, die coating method, spray coating method, doctor coating method, kneader coating method, flow coating method, screen printing method, cast. Law etc. can be mentioned. A spin coating method, a microgravure coating method, a die coating method, or the like is suitable for producing the resin layer 31, and the spin coating method is particularly suitable from the viewpoint of forming the resin layer 31 into a thin film of 1 μm or less.

The thickness of the resin layer 31 can be, for example, 0.1 μm or more and 10.0 μm or less, preferably 0.5 μm or more and 5.0 μm or less, and 1.0 μm or more 3 from the viewpoint of improving the transferability of the convex pattern. More preferably, it is 0.0 μm or less.

For the transfer resin layer 32, a composition containing the monomer (main agent) exemplified as the material of the insulating film 20, a curing agent and, if necessary, other components is used as a transfer resin paste, and this is applied onto the resin layer 31. Can be provided by

The viscosity of the transfer resin paste can be varied depending on the coating method, but is preferably 10 mPa · s or more and 10000 mPa · s or less from the viewpoint of improving the transferability of the convex pattern. When the viscosity of the transfer resin paste is in the above range, it is possible to prevent insufficient filling of the mold 40 having the convex pattern due to the fluidity being too high or too low, and the pattern. It becomes easier to prevent defects. From the viewpoint of further improving the transferability of the convex pattern, the viscosity of the transfer resin paste is preferably 50 mPa · s or more and 1000 mPa · s or less, and more preferably 100 mPa · s or more and 500 mPa · s or less.

In this specification, the viscosity of the paste means a value measured at 20 ° C. using an E-type viscometer.

The transfer resin paste can also be diluted with an organic solvent to adjust the viscosity. When the transfer resin paste is diluted with an organic solvent, it is preferable to remove the organic solvent by drying before pressing the mold 40 against the transfer resin layer 32. By removing the organic solvent, air bubbles generated from the transfer resin layer 32 can be suppressed, and the appearance of the transfer surface is improved.

Examples of the organic solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, toluene, tetrahydrofuran, acetonitrile and the like. One of these may be used alone, or two or more thereof may be used in combination. From the viewpoint of reducing the amount of the organic solvent remaining in the transfer resin layer 32, the above-mentioned organic solvent is preferable, and methyl ethyl ketone is particularly preferable.

As the mold 40 having a convex pattern, for example, a mold made of various materials such as nickel, silicon, and plastic can be produced and used by a known method. It is possible to form a mold having a convex pattern by an electroforming method in the case of nickel and an etching method in the case of silicon. In the case of plastic, a mold having a convex pattern can be formed by transferring a concave pattern made of nickel or silicon to plastic.

The convex pattern is provided so that the above-mentioned through hole is formed. For example, when a through hole having a circular cross-sectional shape is provided, a mold having a cylindrical (pillar) pattern can be used. The height, diameter, and arrangement of the pillars at this time are set so that the thickness of the insulating film 20 described above, the diameter of the through holes, and the arrangement of the through holes can be obtained. In step 2, the convex pattern can penetrate the transfer resin layer 32 and reach the resin layer 31.

The transfer resin layer 32 through which the convex pattern penetrates can be cured by, for example, irradiating with ^{ultraviolet rays having a wavelength of 200 to 400 nm at 500 to 2000 mJ / cm 2.}

[Manufacturing method of anisotropic conductive film]
Next, an embodiment of the method for producing an anisotropic conductive film according to the present invention will be described with reference to FIGS. 5 to 6.

The method for producing the anisotropic conductive film of the present embodiment shown in FIGS. 5 to 6 is as follows.
Step 1 ((a) of FIG. 5) in which the release film 12, the first adhesive layer 22, and the insulating film 20 having the through holes 21 are laminated in this order is prepared.
Step 2 (FIG. 5 (b)) of filling the through holes 21 of the insulating film 20 with the conductive particles P,
Step 3 ((a) of FIG. 6) in which the second adhesive layer 23 is laminated on the surface of the insulating film 20 opposite to the first adhesive layer 22
To be equipped.

The laminate in step 1 is, for example, the easy-adhesive film 30, the resin layer 31, and the insulating film 20 produced by the same method as above on the first adhesive layer 22 provided on the release film 12. The elements laminated in this order can be obtained by laminating the insulating film 20 so as to be in contact with the first adhesive layer 22, and then peeling off the easy-adhesive film 30 and the resin layer 31.

For the lamination, for example, a hot roll laminator or the like can be used.

As a method of filling the through holes 21 of the insulating film 20 with conductive particles, for example, the conductive particles are sprayed on the insulating film 20 and then scraped off with a brush, a brush, a blade, or the like, and the conductive particles P are formed in the through holes 21. A method of filling can be mentioned. The conductive particles that are not filled in the through holes 21 can be removed by using an air blow, an adhesive roll, an electrostatic roll, or the like, but from the viewpoint of selectively removing only the conductive particles that are not filled in the through holes 21. It is preferable to use an electrostatic roll.

In the present embodiment, the thickness T of the insulating film 20 is 0.4 times or more and 1.0 times or less, 0.4 times or more and less than 1.0 times, or 0.5 times the particle size D of the conductive particles P. It is preferable to use the insulating film 20 and the conductive particles P that satisfy the relationship of 0.8 times or more. Thus, the number of through holes per 1 mm ² of the insulating film 20 and the number of conductive particles when an MN _H and MN _p respectively, be the MN _p less 0.9 MN _H or 1.0 MN _H It will be easy.

Further, when the insulating film 20 having a through hole having a circular cross-sectional shape is used, the insulation satisfies the relationship that the diameter W of the through hole is 1.0 times or more and 1.2 times or less the particle size D of the conductive particles. It is preferable to use the sex film 20 and the conductive particles P. This makes it easy to fill one through hole with one conductive particle, and the ratio of the conductive particles existing apart from the other conductive particles in the conductive particles can be set to 97% or more. When an insulating film 20 having a through hole having a cross-sectional shape other than a circular shape is used, the maximum amount of conductive particles that can move in the through hole in a direction orthogonal to the axis (that is, the thickness direction of the insulating film 20). The above effect can be obtained by using the insulating film 20 and the conductive particles P that satisfy the relationship that the distance is 0 times or more and 0.2 times or less the particle size D of the conductive particles.

In step 3, for example, the second adhesive layer 23 provided on the release film can be laminated using, for example, a hot roll laminator or the like.

As a method of providing the first adhesive layer 22 or the second adhesive layer 23 on the release film, the adhesive component and the film exemplified as the materials of the first adhesive layer 22 and the second adhesive layer 23. A composition containing a forming agent and, if necessary, other components may be used as an adhesive paste, which may be applied on a release film.

The viscosity of the adhesive paste can be varied depending on the application and coating method, but from the viewpoint of suppressing separation of the formulation and improving compatibility, it is preferably 10 mPa · s or more and 10000 mPa · s or less, and 50 mPa. -It is more preferable that the value is s or more and 30,000 mPa · s or less. Further, from the viewpoint of improving the appearance of the anisotropic conductive film, the viscosity of the adhesive paste is preferably 100 mPa · s or more and 10000 mPa · s or less. Within this range, it is possible to suppress the separation of the formulation in the adhesive paste, and it is easy to suppress the deterioration of the appearance due to the generation of air bubbles, streaks, etc. on the coated surface.

As a method for applying the adhesive paste, a known method can be used. For example, spin coating method, roller coating method, bar coating method, dip coating method, micro gravure coating method, curtain coating method, die coating method, spray coating method, doctor coating method, kneader coating method, flow coating method, screen printing method, The cast method and the like can be mentioned. Of these, the die coating method is particularly preferable from the viewpoint of layer thickness accuracy.

The adhesive paste can contain a solvent such as an organic solvent, and the thickness of the resin paste can be appropriately adjusted depending on the ratio of the solvent. Examples of the organic solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, toluene, tetrahydrofuran, acetonitrile and the like. One of these may be used alone, or two or more thereof may be used in combination.

The drying temperature of the adhesive paste is preferably, for example, 20 ° C. or higher and 100 ° C. or lower. When the drying temperature is 20 ° C. or higher, it is difficult for the solvent to remain in the first adhesive layer 22 or the second adhesive layer 23, and it is possible to prevent the connection appearance from being deteriorated by air bubbles due to the residual solvent during crimping. Can be done. On the other hand, when the drying temperature is 100 ° C. or lower, the reaction between the monomer as the adhesive component and the curing agent is unlikely to occur, and the curing of the first adhesive layer 22 or the second adhesive layer 23 is suppressed. It's easy to do. From the viewpoint of volatilizing the solvent contained in the adhesive paste, the drying temperature is preferably 40 ° C. or higher and 100 ° C. or lower, and more preferably 50 ° C. or higher and 80 ° C. or lower.

The anisotropic conductive film according to the present invention can be produced by appropriately modifying the above-mentioned method or by a method other than the above-mentioned method. For example, in the method of the above embodiment, the second adhesive layer may be formed by coating. It is also possible to produce an anisotropic conductive film by forming a second adhesive layer and providing an insulating film and a first adhesive layer on the second adhesive layer.

[Structure of connection structure]
FIG. 7 is a schematic cross-sectional view showing an embodiment of the connection structure according to the present invention. As shown in the figure, the connection structure 1 includes a first circuit member 2 and a second circuit member 3 facing each other, and a cured product 4 of an anisotropic conductive film connecting these circuit members 2 and 3. It is configured with.

The first circuit member 2 is, for example, a tape carrier package (TCP), a printed wiring board, a semiconductor silicon chip, or the like. The first circuit member 2 has a plurality of bump electrodes 6 on the mounting surface 5a side of the main body 5. The bump electrode 6 has, for example, a rectangular shape in a plan view, and has a thickness of, for example, 3 μm or more and less than 18 μm. For example, Au or the like is used as the material for forming the bump electrode 6, and the bump electrode 6 is more easily deformed than the conductive particles P contained in the cured product 4 of the anisotropic conductive film. An insulating layer may be formed on the mounting surface 5a where the bump electrode 6 is not formed.

The second circuit member 3 is, for example, a glass substrate or a plastic substrate in which a circuit is formed of ITO, IZO, metal or the like used for a liquid crystal display, a flexible printed circuit board (FPC), a ceramic wiring board, or the like. As shown in FIG. 7, the second circuit member 3 has a plurality of circuit electrodes 8 corresponding to the bump electrodes 6 on the mounting surface 7a side of the main body 7. Like the bump electrode 6, the circuit electrode 8 has a rectangular shape in a plan view, and has a thickness of, for example, about 100 nm. The surface of the circuit electrode 8 is one selected from, for example, gold, silver, copper, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, indium tin oxide (ITO), and indium zinc oxide (IZO). It is composed of two or more kinds of materials. The mounting surface 7a may also have an insulating layer formed on a portion where the circuit electrode 8 is not formed.

The cured product 4 is formed by using, for example, the anisotropic conductive film shown in FIG. 1 so that the first adhesive layer 22 side faces the second circuit member 3 side, and is formed with the cured product of the anisotropic conductive film. can do. This cured product contains an insulating film 20 having a through hole and conductive particles P which are arranged in the through hole and are interposed between the bump electrode 6 and the circuit electrode 8 to electrically connect both electrodes. Can be included.

The conductive particles P may be unevenly distributed on the side of the second circuit member 3, and are interposed between the bump electrode 6 and the circuit electrode 8 in a state of being slightly flattened by crimping. As a result, an electrical connection between the bump electrode 6 and the circuit electrode 8 is realized. Further, the conductive particles P are separated by the insulating film 20 between the adjacent bump electrodes 6 and 6 and between the adjacent circuit electrodes 8 and 8, and the adjacent bump electrodes 6 and 6 and the adjacent circuit electrodes 8 and 8 are separated from each other. Electrical insulation between the eight is realized.

[Manufacturing method of connection structure]
8 and 9 are schematic cross-sectional views showing a manufacturing process of the connection structure shown in FIG. 7. In forming the connection structure 1, first, the anisotropic conductive film 11 from which the release film 12 has been peeled off is placed so as to face the mounting surface 7a, and the first adhesive layer 22 is placed on the second circuit member 3. Laminate. Next, as shown in FIG. 9, the first circuit member 2 is arranged on the second circuit member 3 on which the anisotropic conductive film 11 is laminated so that the bump electrode 6 and the circuit electrode 8 face each other. .. Then, while heating the anisotropic conductive film 11, the first circuit member 2 and the second circuit member 3 are pressed in the thickness direction.

As a result, the adhesive component contained in the anisotropic conductive film 11 flows, the distance between the bump electrode 6 and the circuit electrode 8 is shortened, and the conductive particles P are meshed with each other, and the adhesive contained in the anisotropic conductive film 11 is engaged. The ingredients cure. Due to the curing of the adhesive component, the bump electrode 6 and the circuit electrode 8 are electrically connected, and the adjacent bump electrodes 6 and 6 and the adjacent circuit electrodes 8 and 8 are electrically insulated from each other. The cured product 4 of the positive electrode film 11 is formed, and the connection structure 1 shown in FIG. 7 is obtained. In the obtained connection structure 1, the cured product 4 of the anisotropic conductive film 11 sufficiently prevents the distance between the bump electrode 6 and the circuit electrode 8 from changing over time, and the long-term reliability of the electrical characteristics is maintained. Can also be secured.

The heating temperature at the time of connection is preferably equal to or higher than the temperature at which the polymerization active species is generated in the curing agent and the polymerization of the polymerization monomer is started. This heating temperature is, for example, 80 ° C. to 200 ° C., preferably 100 ° C. to 180 ° C. The heating time is, for example, 0.1 seconds to 30 seconds, preferably 1 second to 20 seconds. If the heating temperature is less than 80 ° C, the curing rate will be slower, and if it exceeds 200 ° C, unwanted side reactions will easily proceed. Further, if the heating time is less than 0.1 seconds, the curing reaction does not proceed sufficiently, and if it exceeds 30 seconds, the productivity of the cured product 4 decreases, and further, an unwanted side reaction tends to proceed.

According to the method for manufacturing a connection structure of the present embodiment, by using the anisotropic conductive film 11, a connection structure capable of achieving both connection reliability between opposing electrodes and insulation between adjacent electrodes in a circuit member can be achieved at the same time. You can get a body.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Formation of adhesive layer]
The adhesive layers were formed by the methods shown below.

(Adhesive layer 1)
45 g of 4,4'-(9-fluorenylidene) -diphenol in a 3000 mL three-necked flask equipped with a Dimroth condenser, a calcium chloride tube, and a stir bar made of polytetrafluoroethylene connected to a stir motor. Sigma Aldrich Japan Co., Ltd.) and 3,3', 5,5'-tetramethylbiphenol diglycidyl ether (manufactured by Mitsubishi Chemical Corporation: YX-4000H) are dissolved in 1000 mL of N-methylpyrrolidone to dissolve the reaction solution. And said. 21 g of potassium carbonate was added thereto, and the mixture was stirred while heating at 110 ° C. with a mantle heater. After stirring for 3 hours, the reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the generated precipitate was collected by suction filtration. The collected precipitate was washed 3 times with 300 mL of methanol to obtain 75 g of phenoxy resin a.

When the molecular weight and dispersity of the phenoxy resin a were measured by gel permeation chromatography (GPC) according to the following conditions, Mn = 15769, Mw = 38045, Mw in terms of polystyrene using a calibration curve using standard polystyrene. / Mn = 2.413.
(Measurement condition)
Equipment: GPC-8020 manufactured by Tosoh Corporation
Detector: RI-8020 manufactured by Tosoh Corporation
Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Kasei Co., Ltd.
Sample concentration: 120 mg / 3 mL
Solvent: Tetrahydrofuran Injection volume: 60 μL
Pressure: 2.94 x 106 Pa (30 kgf / cm ² )
Flow rate: 1.00 mL / min

Next, 50 parts by mass of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation: jER828), 5 parts by mass of 4-hydroxyphenylmethylbenzylsulfonium hexafluoroantimonate as a curing agent, and 50 parts of phenoxy resin a as a film forming material. By mass, was dissolved in methyl ethyl ketone and mixed to prepare an adhesive paste.

The obtained adhesive paste was applied onto a PET resin film having a thickness of 50 μm using a coater, and dried with hot air at 70 ° C. for 5 minutes to form an adhesive layer 1 having a thickness of 0.8 μm.

(Adhesive layer 2)
45 parts by mass of bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation: jER807), 5 parts by mass of 4-hydroxyphenylmethylbenzylsulfonium hexafluoroantimonate as a curing agent, and bisphenol A / bisphenol F copolymerized phenoxy as a film forming material. 55 parts by mass of a resin (manufactured by Nippon Steel & Sumitomo Metal Chemical Corporation: YP-70) was dissolved and mixed in methyl ethyl ketone to prepare an adhesive paste.

The obtained adhesive paste was applied onto a PET resin film having a thickness of 50 μm using a coater, and dried with hot air at 70 ° C. for 5 minutes to form an adhesive layer 2 having a thickness of 15 μm.

(Adhesive layer 3)
The adhesive layer 3 was formed in the same manner as the adhesive layer 1 except that the thickness was changed to 0.3 μm.

[Formation of insulating film]
Insulating films were formed by the methods shown below.

(Insulating film A)
A solution of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: BL-10) dissolved in methyl ethyl ketone is placed on an easily adhesive-treated PET resin film (manufactured by Toyo Spinning Co., Ltd .; Cosmoshine A4100) having a thickness of 100 μm. The film was applied using a coater and dried with hot air at 70 ° C. for 5 minutes to form a resin layer having a thickness of 2 μm.

As an acrylate, 100 parts by mass of tri (propylene glycol) diacrylate (manufactured by Osaka Organic Chemical Co., Ltd .; TPGDA) and 52 parts by mass of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as a photoradical generator are released. As a mold, a solvent-free UV curable mold release agent (manufactured by Shinetsu Chemical Industry Co., Ltd .: KF-2005) was mixed in an amount of 0.5 parts by mass to prepare a transfer resin paste.

The obtained transfer resin paste was applied onto the resin layer using a coater to form a transfer resin layer having a thickness of 3 μm. A nickel mold having columnar pillars having a diameter of 3.5 μm and a height of 4.0 μm in a hexagonal arrangement with a pitch of 6.2 μm was pressed against the transfer resin layer. Next, after irradiating 500 mJ of ultraviolet rays having a wavelength of 365 nm, the mold is released to have a thickness of 2.5 μm having ^{29000 circular through holes having a cross-sectional shape of 3.5 μm in diameter at a density of 29000 pieces / mm 2.} An element having an insulating film A was obtained.

(Insulating film B)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer is changed, the thickness is 2.0 μm having circular through holes having a cross-sectional shape of 3.5 μm at a density of ^{29000 pieces / mm 2.} An element having the insulating film B of the above was obtained.

(Insulating film C)
Similar to the formation of the insulating film A except that the thickness of the transfer resin layer is changed, the thickness is 1.5 μm, which has ^{29000 circular through holes having a cross-sectional shape of 3.5 μm in diameter and a density of 2 mm 2.} An element having the insulating film C of the above was obtained.

(Insulating film D)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer and the convex pattern of the nickel mold were changed, the through holes having a cross-sectional shape of 4.5 μm in diameter were formed at a density of ^{25,000 / mm 2.} An element having a hexagonally arranged insulating film D having a thickness of 1.5 μm was obtained.

(Insulating film E)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer and the convex pattern of the nickel mold were changed, through holes having a cross-sectional shape of 3.5 μm in diameter were formed at a density of ^{10000 / mm 2.} An element having a hexagonally arranged insulating film E having a thickness of 1.5 μm was obtained.

(Insulating film F)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer and the convex pattern of the nickel mold were changed, the through holes having a cross-sectional shape of 3.5 μm in diameter were formed at a density of ^{5000 pieces / mm 2.} An element having a hexagonally arranged insulating film F having a thickness of 1.5 μm was obtained.

(Insulating film G)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer was changed, circular through holes having a cross-sectional shape of 3.5 μm were arranged in a hexagonal manner at a density of ^{29000 pieces / mm 2.} An element having an insulating film G of 1.0 μm was obtained.

(Insulating film H)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer was changed, circular through holes having a cross-sectional shape of 3.5 μm were arranged in a hexagonal manner at a density of ^{29000 pieces / mm 2.} An element having an insulating film H of 3.5 μm was obtained.

(Insulating film I)
Similar to the formation of the insulating film A, except that the thickness of the transfer resin layer and the convex pattern of the nickel mold were changed, the through holes having a cross-sectional shape of 5.0 μm in diameter were formed at a density of ^{25,000 / mm 2.} An element having a hexagonally arranged insulating film I having a thickness of 1.5 μm was obtained.

[Manufacturing of anisotropic conductive film]

( Reference example 1)
The adhesive layer 1 as the first adhesive layer and the element having the insulating film A are bonded to each other at 40 ° C. using a hot roll laminator, and then the easy-adhesive film and the resin layer are separated from the insulating film A. It peeled off.

Next, conductive particles (average particle size 3.3 μm, specific gravity 2.5) in which a nickel layer having a thickness of 0.2 μm is provided on the surface of the particles having polystyrene as the core are sprayed on the insulating film A as conductive particles. Then, it was scraped off using a squeegee, and the through holes were filled with conductive particles. Subsequently, the conductive particles that were not filled in the through holes were removed using an electrostatic cleaner.

Next, the adhesive layer 2 was bonded to the insulating film A at 40 ° C. using a hot roll laminator to obtain an anisotropic conductive film 1.

( Reference Examples 2 to 6)
The anisotropic conductive films 2 to 6 were obtained in the same manner as in Reference Example 1 except that the elements having the insulating films B to F were used instead of the elements having the insulating films A.

(Example 7)
An anisotropic conductive film 7 was obtained in the same manner as in Reference Example 1 except that the adhesive layer 3 was used instead of the adhesive layer 1.

(Comparative Example 1)
An anisotropic conductive film 8 was obtained in the same manner as in Reference Example 1 except that the insulating film A was removed after filling with the conductive particles.

(Comparative Examples 2 to 4)
The anisotropic conductive films 9 to 11 were obtained in the same manner as in Reference Example 1 except that the elements having the insulating films GI were used instead of the elements having the insulating films A.

[Evaluation of anisotropic conductive film]
(Filling rate)
For the anisotropic conductive films 1 to 11, the ^{number of conductive particles in the range of 50,000 μm 2} was actually measured at 20 places, and the average value thereof was converted into the number of conductive particles per ^{1 mm 2.} A conductive particle number MN _p per this 1 mm ^2, and a through-hole number MN _H per 1 mm ² of the insulating film was calculated filling factor represented by the following formula.
Filling rate (%) = (MN _p / MN _H ) x 100

(Single dispersion rate)
For the anisotropic conductive films 1 to 11, ^{the range of 2500 μm 2} was observed, and the total number Nt of the conductive particles and the number Nm of the conductive particles (conductive particles in the monodisperse state) existing apart from the other conductive particles were obtained. It was. From these values, the ratio (monodispersity) of the conductive particles existing apart from the other conductive particles in the conductive particles was calculated from the following formula.
Monodispersity (%) = (Nm / Nt) x 100

A metallurgical microscope was used to actually measure the conductive particles. The results are summarized in the table below.

[Preparation of connection structure]
As the first circuit member, an IC chip in which bump electrodes are arranged in a staggered pattern in two rows (outer diameter 2 mm × 20 mm, thickness 0.3 mm, bump electrode size 70 μm × 15 μm, bump electrode distance 15 μm, bump electrode thickness 15 μm) ) Was prepared. Further, as the second circuit member, an ITO wiring pattern (pattern width 20 μm, space between electrodes 10 μm) formed on the surface of a glass substrate (Corning Inc .: # 1737, 38 mm × 28 mm, thickness 0.3 mm) is formed. Got ready.

The PET resin film on the first adhesive layer side of the anisotropic conductive film (2.5 mm × 25 mm) according to Reference Examples 1 to 6, Examples 7 and Comparative Examples 1 to 4 was peeled off, and the first adhesive layer was peeled off. Using a thermocompression bonding device consisting of a stage (150 mm x 150 mm) consisting of a ceramic heater and a tool (3 mm x 20 mm) on a glass substrate with the side surface at 80 ° C., 0.98 MPa (10 kgf / cm ² ). It was attached by heating and pressurizing for 2 seconds under the conditions.

Next, the other PET resin film of the anisotropic conductive film is peeled off, the bump electrode of the IC chip and the circuit electrode of the glass substrate are aligned, and then a stage (150 mm × 150 mm) and a tool (150 mm × 150 mm) made of a ceramic heater ( Using a thermocompression bonding device composed of 3 mm x 20 mm), the connection structure is heated and pressurized for 5 seconds under the conditions of the measured maximum reaching temperature of the anisotropic conductive film of 170 ° C. and the area conversion pressure of 70 MPa at the bump electrode. Got

[Evaluation of connection structure]
In the connection structure obtained by using each of the heterogeneous conductive films of Reference Examples 1 to 6, Examples 7 and Comparative Examples 1 to 4, the capture rate of conductive particles between the bump electrode and the circuit electrode, and the bump electrode The connection resistance between the circuit electrodes and the insulation resistance between the adjacent circuit electrodes were evaluated.

(Capture rate)
The number of conductive particles MN _p ^{per 1 mm 2} in the isotropic conductive film, the _{average value N b} (measured at 200 points) of the number of conductive particles on the bump electrode, and the area S of the bump electrode were obtained and expressed by the following formulas. The supplement rate was calculated.
Capture rate (%) = [(N _b / S) / MN _p ] × 100

(Connection resistance and insulation resistance)
The connection resistance was measured by the four-terminal measurement method, and the average value of the measurements at 14 points was obtained. A multimeter (manufactured by ETAC: MLR21) was used for the measurement.
The evaluation of the connection resistance is A judgment when it is smaller than 1.0Ω, B judgment when it is 1.0Ω or more and less than 2.0Ω, C judgment when it is 2.0Ω or more, and D judgment when a connection failure occurs. did.
For the insulation resistance, a voltage of 50 V was applied to the obtained connection structure, and the insulation resistance between the circuit electrodes at a total of 1440 locations was measured collectively.
The insulation resistance evaluation, a greater than 10 ⁹ Omega A determination, B determines if it is less than or 10 ⁸ Ω 10 ⁹ Ω, C determine if it is less than 10 ⁸ Omega, the event of a short circuit by D determined ..

1 ... connection structure, 2 ... first circuit member, 3 ... second circuit member, 4 ... cured product, 6 ... bump electrode, 8 ... circuit electrode, 10 ... anisotropic conductive film (with release film), 11 ... Laminated body (anisotropic film), 12 ... Release film, 20 ... Insulating film, 21 ... Through hole, 22 ... First adhesive layer, 23 ... Second adhesive layer, 30 ... Easy adhesive film, 31 ... resin layer, 32 ... transfer resin layer, 40 ... type.

Claims (9)

A first adhesive layer, an insulating film which is a film and has through holes extending in the thickness direction of the film, and a second adhesive layer are provided in this order.
It has conductive particles arranged in the through hole and has
The thickness of the insulating film is 0.4 times or more and 1.0 times or less the particle size of the conductive particles.
The number of the through-holes per 1 mm ² of the insulating film and the number of the conductive particles when the MN _H and MN _p respectively, MN _p is Ri der least 1.0 MN _H below 0.9 MN _H,
The thickness of the first adhesive layer is 0.1 μm or more and 0.5 μm or less.
An anisotropic conductive film. The anisotropic conductive film according to claim 1, wherein the number of through holes per 1 mm ^{2 of the insulating film is 5000 or more and 30,000 or less.} The anisotropic conductive film according to claim 1 or 2, wherein the ratio of the conductive particles existing apart from the other conductive particles in the conductive particles is 97% or more. The anisotropic conductive film according to any one of claims 1 to 3, wherein the average particle size of the conductive particles is 2.5 μm or more and 6.0 μm or less. The ratio Da / Db of the thickness Da of the first adhesive layer to the thickness Db of the second adhesive layer is 0.1 / 10 to 0.5 / 10, according to claims 1 to 4. The anisotropic conductive film according to any one of the above. The first circuit member with the first electrode and
A second circuit member having a second electrode corresponding to the first electrode, and
The cured product of the anisotropic conductive film according to any one of claims 1 to 5, wherein the first adhesive layer side faces the second circuit member side, and the first circuit member and the second circuit member. A connection structure comprising a connecting portion for adhering the circuit member of the above and electrically connecting the first electrode and the second electrode. The connection structure according to claim 6, wherein the first electrode is a bump electrode, and the second electrode is a circuit electrode corresponding to the bump electrode. The invention according to any one of claims 1 to 5, between the first circuit member having the first electrode and the second circuit member having the second electrode corresponding to the first electrode. A connection having a step of interposing an anisotropic conductive film so that the first adhesive layer side faces the second circuit member side and thermocompression bonding the first circuit member and the second circuit member. Method of manufacturing the structure. The method for manufacturing a connection structure according to claim 8 , wherein the first electrode is a bump electrode, and the second electrode is a circuit electrode corresponding to the bump electrode.

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