HK1227180A1 - Anisotropic conductive film and method for producing same - Google Patents

Description

Anisotropic conductive film and method for producing same

Technical Field

The invention relates to an anisotropic conductive film and a method for manufacturing the same.

Background

In recent years, from the viewpoint of application to high-density mounting, an anisotropic conductive film having a two-layer structure in which conductive particles for anisotropic conductive connection are arranged in a single layer on an insulating adhesive layer has been proposed in order to improve conduction reliability and insulation, improve a capture rate of mounted conductive particles, reduce manufacturing cost, and the like (patent document 1).

The anisotropic conductive film with the double-layer structure can be prepared by the following method: after arranging conductive particles in a single layer and densely packed on a transfer layer, the transfer layer is subjected to biaxial stretching treatment to form a transfer layer in which the conductive particles are uniformly arranged at predetermined intervals, the conductive particles on the transfer layer are transferred onto an insulating resin layer containing a thermosetting resin and a polymerization initiator, and further another insulating resin layer containing a thermosetting resin but not containing a polymerization initiator is laminated on the transferred conductive particles (patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4789738.

Disclosure of Invention

Problems to be solved by the invention

However, in the two-layer anisotropic conductive film of patent document 1, an insulating resin layer containing no polymerization initiator is used, and although the conductive particles are uniformly arranged at a single layer and at predetermined intervals, the insulating resin layer containing no polymerization initiator is likely to cause a large resin flow due to heating at the time of anisotropic conductive connection, and the conductive particles are likely to flow along the resin flow, which causes problems such as a decrease in the capture rate of the mounted conductive particles, a short circuit, and a decrease in the insulation.

The invention aims to: the anisotropic conductive film of the present invention has a multilayer structure including conductive particles arranged in a single layer, and can achieve good conduction reliability, good insulation properties, and a good capture rate of the mounted conductive particles.

Means for solving the problems

The present inventors have found that an anisotropic conductive film obtained by arranging conductive particles in a single layer on a photopolymerizable resin layer so as to be embedded at a specific ratio, irradiating ultraviolet rays to fix or temporarily fix the conductive particles, and further laminating a heat or photo cation, anion, or radical polymerizable resin layer on the fixed or temporarily fixed conductive particles can achieve the above object; thus, the present invention has been completed.

That is, the present invention provides an anisotropic conductive film comprising a 1 st connection layer and a 2 nd connection layer formed on one surface thereof, wherein:

the 1 st connecting layer is a photo-polymerization resin layer,

the 2 nd connecting layer is a resin layer with heat or light cation, anion or free radical polymerization,

the conductive particles for anisotropic conductive connection are arranged in a single layer on the 2 nd connection layer side surface of the 1 st connection layer, and the embedding rate of the conductive particles in the 1 st connection layer is 80% or more, or 1% or more and 20% or less. Here, the embedding rate indicates the degree of embedding of the electronic particles in the 1 st connection layer, and may be defined as a ratio (embedding rate) of a depth Lb of embedding of the conductive particles in the 1 st connection layer to a particle diameter La of the conductive particles, and may be obtained by an expression of "embedding rate (%) = (Lb/La) × 100".

The 2 nd connecting layer is preferably a thermally polymerizable resin layer using a thermal polymerization initiator that initiates polymerization reaction by heating, but may be a photopolymerizable resin layer using a photopolymerization initiator that initiates polymerization reaction by light. The resin layer may be a thermally and/or photopolymerizable resin layer using a thermal polymerization initiator and a photopolymerization initiator in combination. Here, the 2 nd connection layer is limited in preparation to the case of a thermopolymerized resin layer using a thermopolymerization initiator.

The anisotropic conductive film of the present invention may have a 3 rd connecting layer having a configuration similar to that of the 2 nd connecting layer on the other surface of the 1 st connecting layer for the purpose of preventing warpage of the joined body due to stress relaxation or the like. That is, the other surface of the 1 st joining layer may have a 3 rd joining layer composed of a heat or photo cation, anion or radical polymerizable resin layer.

The 3 rd connecting layer is preferably a thermally polymerizable resin layer using a thermal polymerization initiator that initiates polymerization reaction by heating, but may be a photopolymerizable resin layer using a photopolymerization initiator that initiates polymerization reaction by light. The resin layer may be a thermally and/or photopolymerizable resin layer using a thermal polymerization initiator and a photopolymerization initiator in combination. Here, the 3 rd connection layer is limited in preparation to the case of a thermopolymerized resin layer using a thermopolymerization initiator.

The present invention also provides a method for producing the anisotropic conductive film, which comprises the following steps (a) to (C) for forming the 1 st connection layer by a one-step photopolymerization reaction, or the following steps (AA) to (DD) for forming the 1 st connection layer by a two-step photopolymerization reaction.

(case of forming the 1 st connecting layer by one-step photopolymerization)

Process (A)

Arranging conductive particles in a single layer on the photopolymerizable resin layer such that the conductive particles have a degree of embedding in the 1 st connecting layer of 80% or more, or 1% or more, and 20% or less;

process (B)

A step of forming a 1 st connection layer having conductive particles fixed to the surface thereof by irradiating the photopolymerizable resin layer on which the conductive particles are arranged with ultraviolet rays to perform photopolymerization; and

process (C)

And a step of forming a 2 nd connecting layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on the surface of the 1 st connecting layer facing the conductive particles.

(case of forming the 1 st connecting layer by two-step photopolymerization)

Working procedure (AA)

Arranging conductive particles in a single layer on the photopolymerizable resin layer such that the conductive particles have a degree of embedding in the 1 st connecting layer of 80% or more, or 1% or more, and 20% or less;

working procedure (BB)

A step of forming a temporary 1 st connection layer on the surface of the substrate by irradiating the photopolymerizable resin layer on which the conductive particles are arranged with ultraviolet rays to perform photopolymerization;

procedure (CC)

Forming a 2 nd connecting layer composed of a thermally cationic, anionic or radical polymerizable resin layer on the surface of the temporary 1 st connecting layer on the conductive particle side; and

working procedure (DD)

And a step of forming a 1 st connection layer by irradiating the 1 st connection layer with ultraviolet rays from the side opposite to the 2 nd connection layer to cause photopolymerization, and then curing the 1 st connection layer.

The initiator used in forming the 2 nd connecting layer in the process (CC) is limited to a thermal polymerization initiator because it does not adversely affect the product life as an anisotropic conductive film, the stability of the connecting and connecting structure. That is, when the 1 st connection layer is irradiated with ultraviolet rays in two steps, the 2 nd connection layer may be limited to a thermopolymerization curable layer due to a restriction in the process. In the case of performing two-step irradiation successively, since the irradiation can be performed in approximately the same step as one step, the same operational effect can be expected.

The present invention also provides a method for producing an anisotropic conductive film having a 3 rd connection layer having the same structure as the 2 nd connection layer on the other surface of the 1 st connection layer, which comprises the following step (Z) after the step (C) in addition to the above steps (a) to (C), or comprises the following step (Z) after the step (DD) in addition to the above steps (AA) to (DD).

Process (Z)

And a step of forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on the surface of the 1 st connection layer opposite to the conductive particle side.

The present invention also provides a method for producing an anisotropic conductive film having a 3 rd connection layer having approximately the same structure as the 2 nd connection layer on the other surface of the 1 st connection layer, which comprises the following step (a) before the step (a) in addition to the above steps (a) to (C), or comprises the following step (a) before the step (AA) in addition to the above steps (AA) to (DD).

Process (a)

And forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on one surface of the photopolymerizable resin layer.

In the step (a) or the step (AA) of the production method having the step (a), the conductive particles may be arranged in a single layer on the other surface of the photopolymerizable resin layer so that the embedding rate of the conductive particles in the 1 st connecting layer is 80% or more, or 1% or more, and 20% or less.

When the 3 rd connection layer is provided by such a step, the polymerization initiator is preferably limited to a polymerization initiator utilizing a thermal reaction for the above-described reasons. However, if the 2 nd and 3 rd connection layers containing a photopolymerization initiator are provided by a method that does not adversely affect the product life and connection after the 1 st connection layer is provided, the anisotropic conductive film containing a photopolymerization initiator that satisfies the gist of the present invention can be produced without any particular limitation.

Note that, any of the 2 nd or 3 rd connection layers of the present invention also functions as an adhesive layer is included in the present invention.

The present invention also provides a connection structure in which a 1 st electronic component and a 2 nd electronic component are anisotropically and electrically connected to each other by the anisotropic conductive film.

ADVANTAGEOUS EFFECTS OF INVENTION

The anisotropic conductive film of the present invention has a 1 st connection layer composed of a photopolymerizable resin layer and a 2 nd connection layer composed of a thermally or photocationically, anionically or radically polymerizable resin layer formed on one surface thereof, and conductive particles for anisotropic conductive connection are arranged in a single layer on the 2 nd connection layer side surface of the 1 st connection layer so that the embedding rate of the conductive particles with respect to the 1 st connection layer is 80% or more, or 1% or more, and 20% or less. Therefore, the conductive particles can be firmly fixed to the 1 st connecting layer, and particularly, in the case where the conductive particles are arranged in a single layer so that the embedding rate is 80% or more, the conductive particles can be more firmly fixed to the 1 st connecting layer. Naturally, the adhesiveness of the anisotropic conductive film is stably improved, and the productivity of anisotropic conductive connection is also improved. Further, the photo radical polymerizable resin layer under (on the back side of) the conductive particles of the 1 st connection layer is not sufficiently irradiated with ultraviolet rays due to the presence of the conductive particles, so that the curing rate is relatively lowered, and good press-fitting property is exhibited, and as a result, good conduction reliability, insulation property, and capture rate of the mounted conductive particles can be realized. In the case of a single-layer arrangement with an embedding rate of 1% to 20%, the adhesion and adhesive strength can be improved because the amount of resin in the 1 st connecting layer is not greatly reduced.

When heat is used for anisotropic conductive connection, the same method as a connection method of a general anisotropic conductive film is used. In the case of using light, the pressing may be performed by a bonding tool before the reaction is completed. In this case, the connecting tool or the like is often heated to promote the flow of the resin and the press-fitting of the particles. In addition, when heat and light are used in combination, the same procedure as described above may be used.

Drawings

FIG. 1 is a cross-sectional view of an anisotropic conductive film according to the present invention.

FIG. 2 is an explanatory view of the step (A) of producing the anisotropic conductive film of the present invention.

Fig. 3A is an explanatory view of the step (B) of producing the anisotropic conductive film of the present invention.

FIG. 3B is a view illustrating a step (B) of producing an anisotropic conductive film according to the present invention.

Fig. 4A is an explanatory view of the step (C) of producing the anisotropic conductive film of the present invention.

Fig. 4B is an explanatory view of the step (C) of producing the anisotropic conductive film of the present invention.

FIG. 5 is a cross-sectional view of the anisotropic conductive film of the present invention.

FIG. 6 is an explanatory view of the step (AA) of producing the anisotropic conductive film of the present invention.

Fig. 7A is an explanatory view of the step (BB) of producing the anisotropic conductive film of the invention.

Fig. 7B is an explanatory view of the step (BB) of manufacturing the anisotropic conductive film of the present invention.

Fig. 8A is an explanatory view of a step (CC) of producing the anisotropic conductive film of the present invention.

Fig. 8B is an explanatory view of the step (CC) of manufacturing the anisotropic conductive film of the present invention.

Fig. 9A is an explanatory view of the step (DD) of producing the anisotropic conductive film of the present invention.

Fig. 9B is an explanatory view of the step (DD) of producing the anisotropic conductive film of the present invention.

Detailed Description

< Anisotropic conductive film >

Hereinafter, a preferred example of the anisotropic conductive film of the present invention will be described in detail.

As shown in fig. 1, the anisotropic conductive film 1 of the present invention has a structure in which a 2 nd connection layer 3 made of a thermally or photo-cationically, anionic, or radical polymerizable resin layer is formed on one surface of a 1 st connection layer 2 made of a photopolymerizable resin layer obtained by photopolymerizing a photopolymerizable resin layer. The conductive particles 4 are arranged in a single layer, preferably uniformly, on the surface 2a of the 1 st connection layer 2 on the 2 nd connection layer 3 side for anisotropic conductive connection. Here, the uniformity refers to a state in which the conductive particles are aligned in a planar direction. This regularity may also be provided at regular intervals.

< 1 st connecting layer 2>

The 1 st connecting layer 2 constituting the anisotropic conductive film 1 of the present invention is a photopolymerizable resin layer obtained by photopolymerization of a photopolymerizable resin layer such as a photo cation, anion or radical polymerizable resin layer, and therefore, conductive particles can be fixed. Further, since the polymerization is performed, the resin is hard to flow even when heated at the time of anisotropic conductive connection, and thus occurrence of short circuit can be greatly suppressed, whereby conduction reliability and insulation can be improved, and mounting particle capture efficiency can be improved. The particularly preferred first connecting layer 2 is a photo radical polymerization resin layer obtained by photo radical polymerization of a photo radical polymerizable resin layer containing an acrylate compound and a photo radical polymerization initiator. The following describes a case where the first connection layer 2 is a photo radical polymerization resin layer.

(acrylate Compound)

As the acrylate compound forming the acrylate unit, a conventionally known photo radical polymerizable acrylate can be used. For example, monofunctional (meth) acrylates (herein, (meth) acrylates include acrylates and methacrylates), and polyfunctional (meth) acrylates having two or more functions can be used. In the present invention, in order to make the adhesive thermosetting, it is preferable to use a polyfunctional (meth) acrylate for at least a part of the acrylic monomer.

If the content of the acrylate compound in the 1 st connecting layer 2 is too small, it tends to be difficult to obtain a viscosity difference with the 2 nd connecting layer 3, and if too large, curing shrinkage tends to be large and workability tends to be lowered, and therefore, it is preferably 2 to 70% by mass, and more preferably 10 to 50% by mass.

(photo radical polymerization initiator)

The photo radical polymerization initiator can be suitably selected from known photo radical polymerization initiators. Examples thereof include acetophenone type photopolymerization initiators, benzil ketal type photopolymerization initiators, phosphorus type photopolymerization initiators, and the like.

The amount of the photo radical polymerization initiator used is preferably 0.1 to 25 parts by mass, and more preferably 0.5 to 15 parts by mass, because if the amount is too small, photo radical polymerization cannot be sufficiently performed, and if the amount is too large, rigidity is lowered.

(conductive particles)

The conductive particles can be suitably selected from conventionally known conductive particles used for anisotropic conductive films. Examples thereof include metal particles such as nickel, cobalt, silver, copper, gold, and palladium, and metal-coated resin particles. More than 2 kinds of them may be used in combination.

The average particle size of the conductive particles is preferably 1 to 10 μm, more preferably 2 to 6 μm, because when the average particle size is too small, it is not able to absorb variations in height of the wiring and tends to increase the resistance, and when the average particle size is too large, it tends to cause short-circuiting.

If the amount of the conductive particles in the 1 st connecting layer 2 is too small, the number of the conductive particles to be mounted decreases, and anisotropic conductive connection becomes difficult, and if too large, short-circuiting may occur, and therefore, the number of the particles per 1 square mm is preferably 50 to 50000, and more preferably 200 to 30000.

The first connecting layer 2 may be formed of a film-forming resin such as a phenoxy resin, an epoxy resin, an unsaturated polyester resin, a saturated polyester resin, a polyurethane resin, a butadiene resin, a polyimide resin, a polyamide resin, or a polyolefin resin, if necessary. The 2 nd and 3 rd connection layers can be used in combination in the same manner.

The thickness of the layer 2 of the 1 st connection layer is preferably 1.0 to 6.0 μm, more preferably 2.0 to 5.0 μm, because the capture rate of the mounting conductive particles tends to decrease when the layer is too thin, and the on-resistance tends to increase when the layer is too thick.

The first connecting layer 2 may further contain an epoxy compound and a thermal or photo cationic or anionic polymerization initiator. In this case, as described below, the 2 nd connecting layer 3 is also preferably a thermally or photocatalytically or anionically polymerizable resin layer containing an epoxy compound and a thermal or photocatalytically or anionically polymerization initiator. This improves the interlayer peel strength. The description is made in the 2 nd connecting layer 3 for the epoxy compound and the thermal or photo cationic or anionic polymerization initiator.

In the 1 st connection layer 2, as shown in fig. 1, the conductive particles 4 are embedded in the 1 st connection layer 2. When the degree of embedding is defined as a ratio of the depth Lb of the conductive particles 4 embedded in the 1 st connection layer 2 to the particle diameter La of the conductive particles 4 (embedding rate), the embedding rate can be obtained by the expression "embedding rate (%) = (Lb/La) × 100".

In the present invention, in order to solve the problem of "the conductive particles can be fixed at a desired position in order to achieve good trapping of the mounting conductive particles", the embedding ratio of the conductive particles 4 in the 1 st connection layer 2 is adjusted so as to be 80% or more, preferably 85% or more, and more preferably greater than 90%. In this case, the conductive particles 4 may be completely buried in the 1 st connection layer 2, but are preferably set to 120% or less.

In the present invention, in order to solve the problem of "fixing conductive particles at desired positions for achieving good capturing of the mounted conductive particles" and the problem of "securing the amount of resin present under the conductive particles for improving the adhesive strength between the 1 st connecting layer 2 and the adherend to achieve good adhesion" in a well-balanced manner, the embedding ratio of the conductive particles 4 in the 1 st connecting layer 2 is adjusted so that the lower limit is 1% or more, preferably more than 1%, and the upper limit is 20% or less, preferably less than 20%.

The embedding rate of the conductive particles 4 in the 1 st connecting layer 2 can be adjusted by, for example, repeatedly pressing the conductive particles with a rubber roller having a release material on the surface. Specifically, the number of repetitions may be reduced when the embedding rate is to be reduced, and the number of repetitions may be increased when the embedding rate is to be increased.

In addition, in the case where the 1 st connecting layer 2 is formed by irradiating the photopolymerizable resin layer with ultraviolet rays, irradiation may be performed from either one of the surface on which the conductive particles are not arranged and the surface on which the conductive particles are arranged, but in the case where irradiation is performed from the side on which the conductive particles are arranged, in the 1 st connecting layer 2, the curing rate of the region 2X of the 1 st connecting layer located between the conductive particles 4 and the outermost surface 2b of the 1 st connecting layer 2 may be made lower than the curing rate of the region 2Y of the 1 st connecting layer located between the conductive particles 4 adjacent to each other. This makes it easy to eliminate the region 2X of the 1 st connection layer when thermocompression bonding for anisotropic conductive connection is performed, and improves the conduction reliability. Here, the curing rate is a value defined as a reduction rate of vinyl groups, and the curing rate of the region 2X of the 1 st connection layer is preferably 40 to 80%, and the curing rate of the region 2Y of the 1 st connection layer is preferably 70 to 100%.

Here, when irradiation is performed from a surface on which the conductive particles are not arranged, there is substantially no difference in the curing rate between the regions 2X and 2Y of the 1 st connecting layer. This is preferable in terms of ACF product quality. The reason for this is that: in the ACF production process, fixing of the conductive particles is promoted, and stable quality can be ensured. The reason for this is that: in general, when the conductive particles are made long as a product, the pressure applied to the aligned conductive particles can be made approximately the same at the start and end of winding, and the alignment can be prevented from being disordered.

The photo radical polymerization in forming the 1 st connection layer 2 may be performed by one step (i.e., one light irradiation), but may be performed by two steps (i.e., two light irradiations). In this case, the light irradiation of the second step is preferably performed from the other surface side of the 1 st junction layer 2 under an oxygen-containing atmosphere (in the atmosphere) after the 2 nd junction layer 3 is formed on one surface of the 1 st junction layer 2. This can expect the following effects: the radical polymerization reaction is inhibited by oxygen, the surface concentration of the uncured component is increased, and the adhesiveness can be improved. Further, since the polymerization reaction is complicated by the two-step curing, it is also expected that the fluidity of the resin or the particles can be controlled finely.

In the two-step photo radical polymerization, the curing rate of the region 2X of the 1 st link layer in the first step is preferably 10 to 50%, the curing rate in the second step is preferably 40 to 80%, the curing rate of the region 2Y of the 1 st link layer in the first step is preferably 30 to 90%, and the curing rate in the second step is preferably 70 to 100%.

When the photo radical polymerization reaction in forming the 1 st connecting layer 2 is performed in two steps, only 1 type of photo radical polymerization initiator may be used as the radical polymerization initiator, but 2 types of photo radical polymerization initiators having different wavelength regions for initiating the radical reaction are preferably used because the adhesiveness is improved. For example, a photo-radical polymerization initiator (for example, IRGACURE369, BASF Japan ltd. (BASF ジャパン (strain))) for initiating a radical reaction by using light having a wavelength of 365nm from an LED light source and a photo-radical polymerization initiator (for example, IRGACURE2959, BASF Japan ltd. (BASF ジャパン (strain))) for initiating a radical reaction by using light from a high-pressure mercury lamp light source are preferably used in combination. Since the combination of the resins is complicated by the use of 2 different types of photo radical polymerization initiators as described above, the behavior of the heat flow of the resins at the time of connection can be more finely controlled. The reason for this is that: when the anisotropic conductive connection is pressed, the particles are easily subjected to a force applied in the thickness direction, and the flow in the plane direction is suppressed, so that the effects of the present invention are more easily exhibited.

The lowest melt viscosity of the 1 st joining layer 2 as measured by a rheometer is higher than the lowest melt viscosity of the 2 nd joining layer 3, and specifically, the numerical value of [ the lowest melt viscosity (mPa · s) of the 1 st joining layer 2) ]/[ the lowest melt viscosity (mPa · s) of the 2 nd joining layer 3) ] is preferably 1 to 1000, and more preferably 4 to 400. The former is preferably 100 to 100000 mPas, more preferably 500 to 50000 mPas, in terms of the minimum melt viscosity. The latter is preferably 0.1 to 10000 mPas, more preferably 0.5 to 1000 mPas.

The formation of the 1 st connection layer 2 may be performed by: the conductive particles are adhered to a photo radical polymerizable resin layer containing a photo radical polymerizable acrylate and a photo radical polymerization initiator by a film transfer method, a die transfer method, an ink jet method, an electrostatic adhesion method, or the like, and ultraviolet rays are irradiated from one side, the opposite side, or both sides of the conductive particles. In particular, from the viewpoint of suppressing the curing rate of the region 2X of the 1 st connecting layer to be relatively low, it is preferable to irradiate ultraviolet light only from the conductive particle side.

< 2 nd connecting layer 3>

The 2 nd connecting layer 3 is composed of a heat or photo cation, anion or radical polymerizable resin layer, preferably a heat or photo cation or anion polymerizable resin layer containing an epoxy compound and a heat or photo cation or anion polymerization initiator, or a heat or photo radical polymerizable resin layer containing an acrylate compound and a heat or photo radical polymerization initiator. Here, the 2 nd connecting layer 3 is formed of a thermally polymerizable resin layer, which is desirable in terms of simplicity of production and quality stability since the polymerization reaction of the 2 nd connecting layer 3 does not occur by ultraviolet irradiation at the time of forming the 1 st connecting layer 2.

In the case where the 2 nd connecting layer 3 is a thermally or photocationically or anionically polymerizable resin layer, it may further contain an acrylate compound and a thermal or photo radical polymerization initiator. This improves the interlayer peel strength with the 1 st connecting layer 2.

(epoxy compound)

When the 2 nd connecting layer 3 is a thermally or photocationically or anionically polymerizable resin layer containing an epoxy compound and a thermal or photocationically or anionically polymerization initiator, the epoxy compound is preferably a compound or resin having 2 or more epoxy groups in the molecule. They may be liquid or solid.

(thermal cationic polymerization initiator)

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators for epoxy compounds can be used, for example, those capable of generating an acid capable of cationic polymerization of a cationically polymerizable compound by heat, and those known as iodine can be usedOnium salts, sulfonium salts,Salts, ferrocenes, and the like, aromatic sulfonium salts exhibiting good latency to temperature can be preferably used.

When the amount of the thermal cationic polymerization initiator to be blended is too small, curing tends to be poor, and when too large, the product life tends to be reduced, and therefore, it is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the epoxy compound.

(thermal anionic polymerization initiator)

As the thermal anionic polymerization initiator, known ones as thermal anionic polymerization initiators for epoxy compounds can be used, and for example, a base capable of anionic polymerization of an anionic polymerizable compound is thermally generated, and known aliphatic amine compounds, aromatic amine compounds, secondary or tertiary amine compounds, imidazole compounds, polythiol compounds, boron trifluoride-amine complexes, dicyandiamide, organic acid hydrazide and the like can be used, and encapsulated imidazole compounds exhibiting good latency to temperature can be preferably used.

When the amount of the thermal anionic polymerization initiator to be blended is too small, curing tends to be poor, and when too large, the product life tends to be reduced, and therefore, it is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the epoxy compound.

(photo cation polymerization initiator and photo anion polymerization initiator)

As the photo cation polymerization initiator or photo anion polymerization initiator for the epoxy compound, known ones can be suitably used.

(acrylate Compound)

When the 2 nd connecting layer 3 is a thermally or photo radical polymerizable resin layer containing an acrylate compound and a thermal or photo radical polymerization initiator, the acrylate compound can be appropriately selected from those described with respect to the 1 st connecting layer 2.

(thermal radical polymerization initiator)

The thermal radical polymerization initiator may be, for example, an organic peroxide or an azo compound, but an organic peroxide which does not generate nitrogen which causes bubbles can be preferably used.

If the amount of the thermal radical polymerization initiator used is too small, curing will be poor, and if it is too large, the product life will be reduced, so that it is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the acrylate compound.

(photo radical polymerization initiator)

As the photo radical polymerization initiator for the acrylate compound, a known photo radical polymerization initiator can be used.

If the amount of the photo radical polymerization initiator used is too small, curing will be poor, and if it is too large, the product life will be reduced, so that it is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the acrylate compound.

(3 rd connecting layer 5)

While the anisotropic conductive film having the two-layer structure of fig. 1 has been described above, the 3 rd connecting layer 5 may be formed on the other surface of the 1 st connecting layer 2 as shown in fig. 5. This can provide an effect of more finely controlling the fluidity of the entire layer. Here, the 3 rd connecting layer 5 may have the same configuration as the 2 nd connecting layer 3. That is, the 3 rd connecting layer 5 is composed of a thermally or photocatalytically or anionically polymerizable resin layer (preferably, a polymerizable resin layer containing an epoxy compound and a thermal or photocatalytically or anionically polymerizable initiator), or a thermally or photoradically polymerizable resin layer (preferably, a polymerizable resin layer containing an acrylate compound and a thermal or photoradically polymerizable initiator). Such a 3 rd connecting layer 5 may be formed on one surface of the 1 st connecting layer after the 2 nd connecting layer is formed and on the other surface of the 1 st connecting layer, or may be formed in advance on the other surface of the 1 st connecting layer or a photopolymerizable resin layer which is a precursor thereof (the surface on which the 2 nd connecting layer is not formed) before the 2 nd connecting layer is formed.

< method for producing Anisotropic conductive film >

The method for producing the anisotropic conductive film of the present invention includes a method for producing the anisotropic conductive film by a one-step photopolymerization reaction and a method for producing the anisotropic conductive film by a two-step photopolymerization reaction.

< method for producing photopolymerization by one step >

An example of producing the anisotropic conductive film of fig. 1 (fig. 4B) by photopolymerization in one step will be described. The preparation examples have the following steps (A) to (C).

(Process (A))

As shown in fig. 2, the conductive particles 4 are arranged in a single layer on the photopolymerizable resin layer 31 formed on the release film 30 as necessary so that the embedding rate is 80% or more, or 1% or more and 20% or less. The method of arranging the conductive particles 4 is not particularly limited, and a method of biaxially stretching an unstretched polypropylene film in example 1 of japanese patent No. 4789738, a method of using a mold in japanese patent application laid-open No. 2010-33793, or the like can be used. In consideration of the size of the connection target, conduction reliability, insulation properties, and capture rate of the mounted conductive particles, the arrangement is preferably arranged so as to be spaced from each other by about 1 to 100 μm on the plane.

The embedding rate can be adjusted by repeatedly pressing an elastic body such as a rubber roller.

(Process (B))

Next, as shown in fig. 3A, the photopolymerizable resin layer 31 on which the conductive particles 4 are arranged is irradiated with Ultraviolet (UV) rays to perform photopolymerization, thereby forming the 1 st connecting layer 2 on the surface of which the conductive particles 4 are fixed. In this case, ultraviolet rays (UV) may be irradiated from the conductive particle side or from the opposite side, but when ultraviolet rays (UV) are irradiated from the conductive particle side, as shown in fig. 3B, the curing rate of a region 2X of the 1 st connecting layer located between the conductive particles 4 and the outermost surface of the 1 st connecting layer 2 may be made lower than the curing rate of a region 2Y of the 1 st connecting layer located between the conductive particles 4 adjacent to each other. This can also provide the effect of reliably reducing the curability of the back surface side of the particles, facilitating press-fitting during bonding, and preventing the particles from flowing.

(Process (C))

Next, as shown in fig. 4A, the 2 nd connecting layer 3 composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer is formed on the surface of the 1 st connecting layer 2 on the conductive particle 4 side. As a specific example, the 2 nd connecting layer 3 formed on the release film 40 by a conventional method is placed on the surface of the 1 st connecting layer 2 on the conductive particle 4 side, and thermocompression bonding is performed to such an extent that excessive thermal polymerization does not occur. Then, the anisotropic conductive film of fig. 4B can be obtained by removing the peeling films 30 and 40.

The anisotropic conductive film 100 of fig. 5 can be obtained by performing the following step (Z) after the step (C).

(Process (Z))

On the opposite surface of the 1 st connecting layer to the conductive particle side, a 3 rd connecting layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer is preferably formed in the same manner as the 2 nd connecting layer. This results in the anisotropic conductive film of fig. 5.

The anisotropic conductive film 100 of fig. 5 may be obtained by performing the following step (a) before the step (a) without performing the step (Z).

(Process (a))

The step is a step of forming a 3 rd connecting layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on one surface of a photopolymerizable resin layer. The anisotropic conductive film 100 of fig. 5 can be obtained by performing the steps (a), (B), and (C) immediately after the step (a). However, in the step (a), the conductive particles are arranged in a single layer on the other surface of the photopolymerizable resin layer so that the embedding rate is 80% or more, or 1% or more and 20% or less.

(preparation method by carrying out two-step photopolymerization)

Next, an example of producing the anisotropic conductive film of fig. 1 (fig. 4B) by photopolymerization in two steps will be described. The preparation examples have the following steps (AA) to (DD).

(Process (AA))

As shown in fig. 6, the conductive particles 4 are arranged in a single layer on the photopolymerizable resin layer 31 formed on the release film 30 as necessary so that the embedding rate is 80% or more, or 1% or more and 20% or less. The method of arranging the conductive particles 4 is not particularly limited, and a method of biaxially stretching an unstretched polypropylene film in example 1 of japanese patent No. 4789738, a method of using a mold in japanese patent application laid-open No. 2010-33793, or the like can be used. In consideration of the size of the connection target, conduction reliability, insulation properties, and capture rate of the mounted conductive particles, the arrangement is preferably arranged so as to be spaced from each other by about 1 to 100 μm on the plane.

(Process (BB))

Next, as shown in fig. 7A, the photopolymerizable resin layer 31 on which the conductive particles 4 are arranged is irradiated with Ultraviolet (UV) rays to perform photopolymerization, thereby forming the temporary 1 st connecting layer 20 on the surface of which the conductive particles 4 are temporarily fixed. In this case, ultraviolet rays (UV) may be irradiated from the conductive particle side or from the opposite side, but when ultraviolet rays (UV) are irradiated from the conductive particle side, as shown in fig. 7B, the curing rate of a region 2X of the 1 st connecting layer located between the conductive particles 4 and the outermost surface of the temporary 1 st connecting layer 20 may be made lower than the curing rate of a region 2Y of the 1 st connecting layer located between the conductive particles 4 adjacent to each other.

(Process (CC))

Next, as shown in fig. 8A, the 2 nd connecting layer 3 composed of a thermally cationic, anionic, or radical polymerizable resin layer is formed on the surface of the temporary 1 st connecting layer 20 on the conductive particle 4 side. As a specific example, the 2 nd connecting layer 3 formed on the release film 40 by a conventional method is placed on the surface of the 1 st connecting layer 2 on the conductive particle 4 side, and thermocompression bonding is performed to such an extent that excessive thermal polymerization does not occur. Then, the temporary anisotropic conductive film 50 of fig. 8B can be obtained by removing the peeling films 30 and 40.

(Process DD)

Next, as shown in fig. 9A, the temporary 1 st connecting layer 20 is irradiated with ultraviolet rays from the side opposite to the 2 nd connecting layer 3 to perform photopolymerization reaction, and the temporary 1 st connecting layer 20 is finally cured to form the 1 st connecting layer 2. This results in the anisotropic conductive film 1 of fig. 9B. The irradiation of ultraviolet rays in this step is preferably performed from the vertical direction with respect to the temporary 1 st connection layer. It is preferable that the irradiation is performed through a mask or a difference is set in the amount of irradiation light according to the irradiation site so that the difference in the curing rate between the regions 2X and 2Y of the 1 st connecting layer does not disappear.

In the case of performing photopolymerization in two steps, the anisotropic conductive film 100 of fig. 5 can be obtained by performing the following step (Z) after the step (DD).

(Process (Z))

The 3 rd connection layer composed of a thermally or photocationically, anionically or radically polymerizable resin layer is preferably formed on the opposite surface of the 1 st connection layer to the conductive particle side, similarly to the 2 nd connection layer. This results in the anisotropic conductive film of fig. 5.

The anisotropic conductive film 100 of fig. 5 may be obtained by performing the following step (a) before the step (AA), without performing the step (Z).

(Process (a))

The step is a step of forming a 3 rd connecting layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on one surface of a photopolymerizable resin layer. The anisotropic conductive film 100 of fig. 5 can be obtained by performing the steps (AA) to (DD) immediately after the step (a). However, in the step (AA), the conductive particles are arranged in a single layer on the other surface of the photopolymerizable resin layer so that the embedding rate is 80% or more, or 1% or more and 20% or less. In this case, as the polymerization initiator used in forming the 2 nd connecting layer, a thermal polymerization initiator is preferably used. In the case of a photopolymerization initiator, the process may adversely affect the product life of the anisotropic conductive film and the stability of the connection and connection structure.

< connection Structure >

The anisotropic conductive film thus obtained can be preferably used for anisotropic conductive connection of a 1 st electronic component such as an IC chip or an IC module to a 2 nd electronic component such as a flexible substrate or a glass substrate. The thus obtained connection structure is also part of the present invention. From the viewpoint of improving the conduction reliability, it is preferable that the 1 st connection layer side of the anisotropic conductive film is disposed on the 2 nd electronic component side such as a flexible substrate, and the 2 nd connection layer side is disposed on the 1 st electronic component side such as an IC chip.

Examples

The present invention will be described in detail with reference to examples.

Examples 1 to 6 and comparative example 1

While the alignment of the conductive particles was performed in accordance with the procedure of example 1 of japanese patent No. 4789738, an anisotropic conductive film having a two-layer structure in which the 1 st connection layer and the 2 nd connection layer were laminated was prepared in accordance with the formulation (parts by mass) shown in table 1.

(layer 1 connection)

Specifically, first, an acrylate compound, a photo radical polymerization initiator, and the like are mixed with ethyl acetate or toluene to prepare a mixed solution so that the solid content is 50 mass%. The mixed solution was coated on a polyethylene terephthalate film having a thickness of 50 μm so as to have a dry thickness of 5 μm, and dried in an oven at 80 ℃ for 5 minutes, thereby forming a photo radical polymerizable resin layer as a precursor layer of the 1 st connection layer.

Next, with respect to the obtained photo radical polymerizable resin layer, conductive particles (Ni/Au plated resin particles, AUL704, waterlogging chemical industry, ltd.) having an average particle diameter of 4 μm were arranged in a single layer so that the embedding rate of the conductive particles with respect to the 1 st connecting layer was a percentage shown in table 1 of the particle diameter by adjusting the number of repeated pressing with a rubber roller from each other by 4 μm. Further, the photo radical polymerizable resin layer was irradiated from the conductive particle side with a light having a wavelength of 365nm and a cumulative light amount of 4000mJ/cm²Thereby forming a 1 st connection layer having conductive particles fixed to the surface thereof.

(2 nd connecting layer)

A mixed solution of a thermosetting resin, a latent curing agent and the like was prepared with ethyl acetate or toluene so that the solid content was 50 mass%. The mixture was coated on a polyethylene terephthalate film having a thickness of 50 μm so as to have a dry thickness of 12 μm, and dried in an oven at 80 ℃ for 5 minutes, thereby forming a 2 nd connecting layer.

(Anisotropic conductive film)

The 1 st connection layer and the 2 nd connection layer thus obtained were laminated with the conductive particles inside, thereby obtaining an anisotropic conductive film.

(connection Structure sample body)

Using the obtained anisotropic conductive film, an IC chip (bump size 30X 85 μm, bump height 15 μm, and bump pitch 50 μm) having a size of 0.5X 1.8X 20.0mm was mounted on a glass wiring substrate (1737F) made by Corning Inc. (コーニング Co.) having a size of 0.5X 50X 30mm under conditions of 180 ℃ and 80MPa for 5 seconds, thereby obtaining a sample of a connection structure.

(test evaluation)

The obtained connection structure sample was evaluated by tests for the "mounted conductive particle capture rate", "conduction reliability", "number of connected particles", and "insulation" of the anisotropic conductive film, as described below. The results obtained are shown in table 1.

In the case of evaluating the "insulation property", a connection structure sample was used, which was obtained by mounting an IC chip (gold-plated bump size 25 × 140 μm, bump height 15 μm, and inter-bump gap 7.5 μm) having a size of 0.5 × 1.5 × 13mm on a glass wiring board (1737F) made by Corning inc., コーニング, having a size of 0.5 × 50 × 30mm under conditions of 180 ℃, 80MPa, and 5 seconds.

Capacity of conductive particles for mounting "

The ratio of "the amount of particles actually captured on the bumps of the connection structure sample body after heating and pressing (after actual mounting)" to "the amount of theoretical particles existing on the bumps of the connection structure sample body before heating and pressing" is obtained by the following mathematical expression.

Mounting conductive particle capture rate (%) = { [ number of particles on bump after heating and pressurizing ]/[ number of particles on bump before heating and pressurizing ] } × 100

"conduction reliability"

The on-resistance of the sample bodies of the connection structures after being left for 500 hours in a high temperature and high humidity environment at 85 ℃ and 85% RH was measured using a digital multimeter (Agilent Technologies Japan, ltd. (アジレント · テクノロジー strain)). In practical use, it is preferably 4 Ω or less.

"number of connected particles"

In a 10mm square region of a sample of a connection structure obtained by observation with an electron microscope at a magnification of 50 times, a connected body in which 2 or more conductive particles are connected in a linear or block shape was counted as one connected particle, and the number of such connected particles was counted. For example, when there are 2 connected particles in which 2 conductive particles are connected and 1 connected particle in which 4 connected particles are connected, the number of connected particles is 3. When the number of the connections is increased, the number of the conductive particles constituting the connection particles also tends to be increased, that is, the independence of the conductive particles occupying the inter-bump gap is easily impaired, and thus the probability of occurrence of a short circuit tends to be increased.

Insulation (incidence of short circuit)'

The short-circuit occurrence rate of the comb TEG pattern with a gap of 7.5 μm was determined. In practice, it is preferably 100ppm or less.

[ Table 1]

As is clear from table 1, in the anisotropic conductive films of examples 1 to 6, since the embedding rate of the conductive particles in the 1 st connection layer was 80% or more, the number of the connection particles was also 10 or less, and the evaluation items of the capture rate of the conductive particles, the conduction reliability, and the occurrence rate of short circuit showed preferable results in terms of practical use.

In contrast, in the anisotropic conductive film of comparative example 1, since the embedding rate of the conductive particles in the 1 st connection layer was 75% or less of 80%, the number of the connected particles was increased, and the short-circuit occurrence rate was increased to 50 ppm.

Example 7

The cumulative light amount at the time of forming the 1 st connection layer was 2000mJ/cm²An anisotropic conductive film was produced in the same manner as in example 1, except that ultraviolet rays were irradiated. The anisotropic conductive film further had a cumulative light amount of 2000mJ/cm from the 1 st connection layer side²The anisotropic conductive film of example 7 in which ultraviolet rays were irradiated from both surfaces of the 1 st connecting layer was obtained by irradiating ultraviolet rays having a wavelength of 365 nm. Using this anisotropic conductive film, a connection structure sample was prepared and evaluated in the same manner as the anisotropic conductive film of example 1, and substantially the same results were obtained without problems in actual use, but the mounted conductive particle capture rate tended to be further improved.

Examples 8 to 12 and comparative examples 2 to 3

The procedure of example 1 was repeated except that the number of times of repeated pressing by the rubber roller was adjusted to arrange the conductive particles in a single layer so that the embedding ratio of the conductive particles to the 1 st connecting layer was a percentage shown in table 2 of the particle diameter, thereby obtaining an anisotropic conductive film and further obtaining a connecting structure sample.

(test evaluation)

The obtained connection structure sample was subjected to test evaluation of the "capture rate of mounted conductive particles", "conduction reliability", and "insulation (short-circuit occurrence rate)" of the anisotropic conductive film in the same manner as in example 1, and further subjected to test evaluation of "adhesive force on the 1 st connection layer side", "adhesive strength (chip shear force)" as described below. The results obtained are shown in table 2.

[ Table 2]

As is clear from table 2, in the anisotropic conductive films of examples 8 to 12, since the embedding rate of the conductive particles in the 1 st connection layer was 1% or more and 20% or less, the evaluation items of the adhesive force, the adhesive strength, the capture rate of the mounted conductive particles, the conduction reliability, and the insulation property (short-circuit occurrence rate) showed preferable results in terms of practical use.

In contrast, in the anisotropic conductive film of comparative example 2, since the embedding rate of the conductive particles into the 1 st connecting layer exceeded 20%, the adhesive strength and the adhesive strength were inferior to those of the anisotropic conductive films of examples 8 to 12. In addition, the incidence of short circuits also increased by a factor of about 2.5. In the anisotropic conductive film of comparative example 3, since the embedding rate of the conductive particles in the first connection layer 1 was less than 1%, the capture rate of the mounted conductive particles was lower than that of the anisotropic conductive films of examples 8 to 12, and the occurrence rate of short circuit as an evaluation index of the insulation property was increased by about 7.5 times.

Example 13

At a cumulative light amount of 2000mJ/cm at the time of forming the 1 st connection layer²An anisotropic conductive film was produced in the same manner as in example 8, except that ultraviolet rays were irradiated. Further, the anisotropic conductive film was irradiated with a cumulative light of 2000mJ/cm from the 1 st connection layer side²The anisotropic conductive film of example 13 was obtained by irradiating ultraviolet rays having a wavelength of 365nm to both sides of the 1 st connecting layer. Using this anisotropic conductive film, a connection structure sample was prepared and evaluated in the same manner as the anisotropic conductive film of example 8, and substantially the same results were obtained without problems in actual use, but the mounted conductive particle capture rate tended to be further improved.

Industrial applicability

The anisotropic conductive film has a two-layer structure in which a 1 st connection layer composed of a photopolymerizable resin layer and a 2 nd connection layer composed of a thermally or photocationically or anionically polymerizable resin layer or a thermally or photoradically polymerizable resin layer are laminated, and conductive particles for anisotropic conductive connection are arranged in a single layer on the 2 nd connection layer side surface of the 1 st connection layer so that the embedding rate with respect to the 1 st connection layer is 80% or more. Therefore, the conductive particles can be fixed well on the 1 st connection layer, and the mounted conductive particle capture rate, conduction reliability, the number of connection particles, and insulation properties are exhibited well. In another embodiment of the anisotropic conductive film according to the present invention, the conductive particles for anisotropic conductive connection are arranged in a single layer so that the embedding ratio of the conductive particles for anisotropic conductive connection to the 1 st connection layer is 1% or more and 20% or less. Therefore, the 1 st connection layer exhibits good adhesiveness and adhesive strength, and exhibits good conduction reliability, insulation (short-circuit occurrence rate), and mounting conductive particle capture rate. Therefore, the anisotropic conductive film of the present invention is useful for anisotropic conductive connection of an electronic component such as an IC chip to a wiring board. The wiring of such electronic components is becoming increasingly narrow, and the present invention exhibits this effect particularly when it contributes to such a technical advance.

Description of the symbols

1. 100 Anisotropic conductive film

2. 1 st connection layer

2X, 2Y region of the No. 1 connection layer

3 the 2 nd connecting layer

4 conductive particles

5 No. 3 connecting layer

30. 40 Release film

20 temporary 1 st connection layer

31 photopolymerizable resin layer

50 temporary anisotropic conductive film

Particle diameter of La conductive particle

Depth of embedding Lb conductive particles in the 1 st connection layer

Claims (16)

1. An anisotropic conductive film having a 1 st connection layer and a 2 nd connection layer formed on one surface thereof, characterized in that:

the 1 st connecting layer is a photo-polymerization resin layer,

the 2 nd connecting layer is a resin layer with heat or light cation, anion or free radical polymerization,

the conductive particles for anisotropic conductive connection are arranged in a single layer on the 2 nd connection layer side surface of the 1 st connection layer, and the embedding rate of the conductive particles in the 1 st connection layer is 80% or more, or 1% or more and 20% or less.

2. The anisotropic conductive film according to claim 1, wherein the 1 st connecting layer is a photo radical polymerization resin layer obtained by photo radical polymerization of a photo radical polymerization resin layer containing an acrylate compound and a photo radical polymerization initiator.

3. The acf of claim 2 wherein the 1 st connection layer further contains an epoxy compound and a thermal or photo cationic or anionic polymerization initiator.

4. The acf of claim 1 or 2 wherein the 2 nd connecting layer is a thermally or photocatalytically or anionically polymerizable resin layer containing an epoxy compound and a thermal or photocatalytically or anionically polymerization initiator, or a thermally or photoradically polymerizable resin layer containing an acrylate compound and a thermal or photoradically polymerization initiator.

5. The acf of claim 4 wherein the 2 nd connecting layer is a thermally or photocatalytically or anionically polymerizable resin layer containing an epoxy compound and a thermal or photocatalytically or anionically polymerization initiator, further containing an acrylate compound and a thermal or photoradically polymerization initiator.

6. The anisotropic conductive film according to any of claims 1 to 5, wherein, in the 1 st connecting layer, a curing rate of the 1 st connecting layer in a region between the conductive particles and an outermost surface of the 1 st connecting layer is lower than a curing rate of the 1 st connecting layer in a region between mutually adjacent conductive particles.

7. The acf of any one of claims 1 to 6 wherein the lowest melt viscosity of the 1 st connection layer is higher than the lowest melt viscosity of the 2 nd connection layer.

8. A production method of the anisotropic conductive film according to claim 1, comprising the following steps (A) to (C):

process (A)

Arranging conductive particles in a single layer on the photopolymerizable resin layer such that the conductive particles have a degree of embedding in the 1 st connecting layer of 80% or more, or 1% or more, and 20% or less;

process (B)

A step of forming a 1 st connection layer having conductive particles fixed to the surface thereof by irradiating the photopolymerizable resin layer on which the conductive particles are arranged with ultraviolet rays to perform photopolymerization; and

process (C)

And a step of forming a 2 nd connecting layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on the surface of the 1 st connecting layer facing the conductive particles.

9. The production method according to claim 8, wherein the ultraviolet irradiation in the step (B) is performed from a side of the photopolymerizable resin layer on which the conductive particles are arranged.

10. A production method for the anisotropic conductive film according to claim 1, comprising the following steps (AA) to (DD):

working procedure (AA)

Arranging conductive particles in a single layer on the photopolymerizable resin layer such that the conductive particles have a degree of embedding in the 1 st connecting layer of 80% or more, or 1% or more, and 20% or less;

working procedure (BB)

A step of forming a temporary 1 st connection layer having conductive particles temporarily fixed to the surface thereof by irradiating the photopolymerizable resin layer on which the conductive particles are arranged with ultraviolet rays to perform photopolymerization;

procedure (CC)

Forming a 2 nd connecting layer composed of a thermally cationic, anionic or radical polymerizable resin layer on the surface of the temporary 1 st connecting layer on the conductive particle side; and

working procedure (DD)

And a step of forming a 1 st connection layer by irradiating the 1 st connection layer with ultraviolet rays from the side opposite to the 2 nd connection layer to perform photopolymerization, and then curing the 1 st connection layer.

11. The production method according to claim 10, wherein the ultraviolet irradiation in the step (BB) is performed from a side of the photopolymerizable resin layer on which the conductive particles are arranged.

12. The production method according to claim 8, wherein the step (C) is followed by the following step (Z):

process (Z)

And a step of forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on the surface of the 1 st connection layer opposite to the conductive particle side.

13. The production method according to claim 8, wherein the following step (a) is provided before the step (A):

process (a)

Forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on one surface of the photopolymerizable resin layer;

in the step (a), the conductive particles are arranged in a single layer at an embedding rate of 80% or more, or 1% or more and 20% or less on the other surface of the photopolymerizable resin layer.

14. The production method according to claim 10, wherein the step (DD) is followed by the step (Z) below:

process (Z)

And a step of forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on the surface of the 1 st connection layer opposite to the conductive particle side.

15. The process according to claim 10, wherein the process comprises the following step (a) before the step (AA):

process (a)

Forming a 3 rd connection layer composed of a thermally or photo-cationically, anionically or radically polymerizable resin layer on one surface of the photopolymerizable resin layer;

in the step (AA), the conductive particles are arranged in a single layer at an embedding rate of 80% or more, or 1% or more and 20% or less on the other surface of the photopolymerizable resin layer.

16. A connection structure obtained by anisotropically and electrically connecting a 1 st electronic component and a 2 nd electronic component with the anisotropic conductive film according to any one of claims 1 to 7.