TWI783897B - Anisotropic conductive film - Google Patents

Abstract

Provided is an anisotropic conductive film capable of handling narrow-pitch bumps and capable of reducing the number density of conductive particles compared with conventional anisotropic conductive films. In the anisotropic conductive film 1A, conductive particles 2 are arranged on the insulating resin adhesive 3, and polygonal repeating units 5 are repeatedly arranged in the vertical and horizontal directions in a plan view. The polygonal repeating units 5 are a plurality of conductive particles. The centers of particles 2 are connected sequentially to form. The sides of the polygon of the repeating unit 5 are oblique to the long-side direction or the short-side direction of the anisotropic conductive film.

Description

Anisotropic Conductive Film

The invention relates to an anisotropic conductive film.

The anisotropic conductive film obtained by dispersing conductive particles in an insulating resin binder is widely used when mounting electronic components such as IC chips on wiring boards and the like. In the anisotropic conductive film, it is strongly required to improve the capture of conductive particles in the bumps and avoid short circuits between adjacent bumps by narrowing the pitch of the bumps accompanying the high-density mounting of electronic components.

In response to this requirement, it has been proposed to arrange the conductive particles in the anisotropic conductive film in a lattice-like arrangement, and to make the arrangement axis inclined relative to the long-side direction of the anisotropic conductive film (Patent Document 1, Patent Document 1, Literature 2).

Patent Document 1: Japanese Patent No. 4887700 Patent Document 2: Japanese Patent Application Laid-Open No. 9-320345

[Problem to be Solved by the Invention]

As described in Patent Documents 1 and 2, when the conductive particles are arranged in a simple lattice, the layout of the bumps is handled by the inclination angle of the arrangement axis or the distance between the conductive particles. Therefore, if the bumps have a narrow pitch, the distance between the conductive particles must be reduced, and the number density of the conductive particles increases, resulting in an increase in the manufacturing cost of the anisotropic conductive film.

In addition, in order to reduce the distance between the conductive particles and avoid short circuit, it is necessary to prevent the conductive particles from flowing away due to the resin flow of the insulating resin adhesive during the anisotropic conductive connection, and the design of the insulating resin adhesive also has restrict.

Therefore, the object of the present invention is to be able to cope with narrow-pitch bumps, and to reduce the number density of conductive particles compared with conventional anisotropic conductive films. [Technical means to solve the problem]

The inventors of the present invention found that instead of arranging the conductive particles of the anisotropic conductive film in a simple lattice-like arrangement in a plan view, the conductive particles are repeatedly arranged in the vertical and horizontal directions by repeating the polygonal units composed of a plurality of conductive particles. Particles, and the sides forming the polygons are obliquely intersected with respect to the long-side direction or the short-side direction of the anisotropic conductive film, thereby solving the above-mentioned problems, and the present invention was conceived.

That is, the present invention provides an anisotropic conductive film in which conductive particles are arranged in an insulating resin binder, and The polygonal repeating unit is repeatedly arranged under the top view, and the polygonal repeating unit is formed by sequentially connecting the centers of a plurality of conductive particles, The polygon of the repeating unit has sides oblique to the long side direction or the short side direction of the anisotropic conductive film. [Effect of Invention]

According to the anisotropic conductive film of the present invention, since each conductive particle is not arranged in a simple lattice-like arrangement, but is set as a repeating unit formed by a plurality of conductive particles, the distance between the conductive particles is shortened Part of it is evenly present in the whole film. Also, since the polygonal shape of the repeating unit has sides obliquely intersecting the long-side direction or the short-side direction of the anisotropic conductive film, the capture property of conductive particles in the bump is high. Therefore, it is possible to connect bumps with a narrow pitch without causing a short circuit.

On the other hand, according to the anisotropic conductive film of the present invention, since the portion where the distance between the conductive particles is enlarged is uniformly present in the entire film, the number density of the conductive particles in the entire anisotropic conductive film can be suppressed. increase, and suppress the increase in manufacturing cost accompanying the increase in the number density of conductive particles. In addition, by suppressing an increase in the number density of conductive particles, it is also possible to suppress an increase in the thrust force necessary to press the jig at the time of anisotropic conductive connection. Therefore, it is possible to reduce the pressure exerted by the self-pressing jig on the electronic parts during anisotropic conductive connection, and prevent deformation of the electronic parts.

Hereinafter, the anisotropic conductive film of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code|symbol represents the same or equivalent component.

＜The overall structure of the anisotropic conductive film＞ FIG. 1A is a plan view showing the arrangement of conductive particles in an anisotropic conductive film 1A according to an embodiment of the present invention, and FIG. 1C is a cross-sectional view thereof. This anisotropic conductive film 1A has a structure in which conductive particles 2 are arranged in a single layer on or near the surface of an insulating resin adhesive 3 , and an insulating adhesive layer 4 is laminated thereon.

Furthermore, as the anisotropic conductive film of the present invention, the insulating adhesive layer 4 may be omitted, and the conductive particles 2 may be embedded in the insulating resin adhesive 3 .

（polybenzoguanamine）等樹脂粒子之表面而成之金屬被覆樹脂粒子等。配置之導電粒子的大小較佳為1 μm以上且30 μm以下，更佳為1 μm以上且10 μm以下，進而較佳為2 μm以上且6 μm以下。 <Conductive Particles> As the conductive particles 2, those of known anisotropic conductive films can be appropriately selected and used. Examples include: metal particles such as nickel, copper, silver, gold, and palladium; polyamide and polyphenylguanidine coated with metal such as nickel;

(polybenzoguanamine) and other resin particles on the surface of metal-coated resin particles. The size of the disposed conductive particles is preferably not less than 1 μm and not more than 30 μm, more preferably not less than 1 μm and not more than 10 μm, still more preferably not less than 2 μm and not more than 6 μm.

The average particle size of the conductive particles 2 can be measured by an image-type or laser-type particle size distribution meter. The anisotropic conductive film can also be observed from a top view, and the particle diameter can be measured and obtained. In this case, it is preferable to measure 200 or more, more preferably to measure 500 or more, and still more preferably to measure 1000 or more.

The surface of the conductive particles 2 is preferably covered by insulating coating or insulating particle treatment. This kind of coating is easy to peel off from the surface of the conductive particles 2, and will not hinder the anisotropic conductive connection. Moreover, the protrusion may be provided in the whole surface or a part of the conductive particle 2. The height of the protrusions is within 20% of the diameter of the conductive particles, preferably within 10%.

＜Configuration of Conductive Particles＞ In FIGS. 1A to 7 below, as an example, an arrangement example of the repeating unit when the polygonal repeating unit 5 is a trapezoid will be described. The disposition of the conductive particles 2 under the top view of the anisotropic conductive film 1A shown in FIG. Alternative two directions (X direction, Y direction) are repeated and arranged on one surface (that is, the entire surface) of the anisotropic conductive film 1 . Furthermore, the anisotropic conductive film of the present invention may have a region where no conductive particles are disposed, if necessary.

The arrangement of the conductive particles 2 can also be regarded as arranging conductive particles in a part of the vertices of the regular triangles when the regular triangles are arranged without gaps (or the vertices of the regular hexagons when the regular hexagons are arranged without gaps). In other words, it can be considered as an arrangement in which conductive particles at specific lattice points are regularly removed from the arrangement of conductive particles existing at each lattice point of the hexagonal lattice. Therefore, the apex of the trapezoid of the repeating unit 5 composed of the conductive particles 2a, 2b, 2c, and 2d becomes a part of the regular hexagon combined with the regular triangle, and exists at the lattice point of the hexagonal lattice. If one of the sides 2a, 2b of the trapezoid is reversed, the side 2c, 2d and the repeating unit of the adjacent trapezoid (that is, the repeating unit composed of conductive particles 2e, 2f, 2g, 2h) side 2g, 2h overlap.

Furthermore, when considering the situation of the repeating unit of the conductive particle 2, as shown in FIG. The direction overlaps one side and repeats, and repeats in the Y direction without overlapping the sides and vertices. In the present invention, the repeating unit is preferably regarded as a polygon composed of more than 4 conductive particles, and is not overlapped. In the case of a side of a corner, it is a polygon that is the smallest unit repeated along the vertical and horizontal directions of the anisotropic conductive film.

Each side of the trapezoid of the repeating unit 5 ( FIG. 1A ) is oblique to the long-side direction and the short-side direction of the anisotropic conductive film 1A. Thereby, the outer tangent line L1 of the longitudinal direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2b which adjoins the conductive particle 2a in the longitudinal direction of the anisotropic conductive film. Moreover, the circumscribed line L2 of the short-side direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2d which adjoins this conductive particle 2a in the short-side direction of the anisotropic conductive film. Since usually in the case of anisotropic conductive connection, the long side direction of the anisotropic conductive film becomes the short side direction of the bump, so if the polygonal side of the repeating unit 5 is aligned with the long side direction or the short The oblique direction of the side can prevent a plurality of conductive particles from being arranged in a straight line along the edge of the bump, thereby avoiding the phenomenon that a plurality of conductive particles arranged in a straight line are detached from the terminal at the same time and become ineffective for conduction. Capability of capturing conductive particles 2 can be improved.

Furthermore, in the present invention, the repeating unit may not necessarily have all its sides obliquely intersecting with the long-side direction or the short-side direction of the anisotropic conductive film, and the short-side direction of each bump becomes the long-side direction of the anisotropic conductive film. In this case, it is preferable that each side of the repeating unit intersects obliquely with the long-side direction or the short-side direction of the anisotropic conductive film from the viewpoint of capturing properties of conductive particles.

On the other hand, when the arrangement pattern of bumps is radial (so-called fan-out bumps), it is preferable that the polygons forming the repeating unit have sides in the long-side direction or short-side direction of the anisotropic conductive film. That is, in order to realize that the bumps to be connected will not be misaligned even if they are thermally expanded, there are cases where the arrangement pattern of the bumps is made radial (for example, Japanese Patent Laid-Open No. 2007-19550, Japanese Patent Laid-Open No. 2015-232660, etc. ), in this case, the angle formed by the long-side direction of each bump and the long-side direction and short-side direction of the anisotropic conductive film gradually changes. Therefore, even if the polygonal side of the repeating unit 5 is not obliquely intersected with the long-side direction or the short-side direction of the anisotropic conductive film, the polygonal side of the repeating unit 5 is also the length of the radially arranged bumps. The edges in the side direction are obliquely intersected. Therefore, it is possible to avoid the phenomenon that most of the conductive particles attached to the edge of the bump are not captured by the bump during the anisotropic conductive connection, resulting in a decrease in the capture ability of the conductive particles.

On the other hand, the radial arrangement pattern of the bumps is usually formed bilaterally symmetrically. Therefore, it is preferable that the polygon forming the repeating unit 5 has the long-side direction or the short-side direction of the anisotropic conductive film in terms of easily confirming whether the connection state is good or not by the indentation after the anisotropic conductive film. The side, especially the polygon forming the repeating unit 5 has the side of the long side direction or the short side direction of the anisotropic conductive film, and is symmetrical with the short side direction or the long side direction of the anisotropic conductive film as the axis of symmetry shape, and the repeating unit 5 is repeatedly arranged along the long-side direction or the short-side direction of the anisotropic conductive film. For example, like the anisotropic conductive film 1Ba shown in FIG. 2A , the trapezoid of the repeating unit 5 can be set as a trapezoid with an axis of symmetry in the short side direction of the anisotropic conductive film, so that its bottom and upper sides are aligned with the anisotropic conductive film. The long-side direction of the anisotropic conductive film is parallel, and, like the anisotropic conductive film 1Bb shown in FIG. .

In the present invention, the arrangement of the conductive particles 2 in the repeating unit 5 or the vertical and horizontal repeating pitches of the repeating unit 5 can be appropriately changed according to the shape or pitch of the terminals to be connected in the anisotropic conductive connection. Therefore, compared with the case where the conductive particles 2 are arranged in a simple lattice shape, the anisotropic conductive film can achieve a higher trapping property with a smaller number of conductive particles as a whole. For example, for the above-mentioned anisotropic conductive film 1Ba, in order to increase the number density of the conductive particles in the longitudinal direction of the anisotropic conductive film, it can also be configured as follows: as shown in FIG. 3A, the anisotropic conductive film 1Ca Repeat the trapezoidal repeating unit 5 in its shape along the width direction of the anisotropic conductive film, and alternately repeat the trapezoidal repeating unit 5 and repeating unit 5B along the long side direction of the anisotropic conductive film, the repeating unit 5B is a shape obtained by inverting the repeating unit of the trapezoid along the axis in the long side direction of the film. In this case, it may also be arranged as follows: Like the anisotropic conductive film 1Da shown in FIG. The repeating unit 5B of the formed shape.

Similarly, for the above-mentioned anisotropic conductive film 1Bb, in order to increase the number density of conductive particles in the short-side direction of the anisotropic conductive film, it can also be configured as follows: the anisotropic conductive film 1Cb as shown in FIG. 3B Generally, the trapezoidal repeating unit 5 is repeated in its shape along the long side direction of the anisotropic conductive film, and the repeating unit 5 and the repeating unit 5B are alternately repeated along the width direction of the anisotropic conductive film. The repeating unit 5B It is a shape obtained by inverting the axis of the repeating unit along the short side direction of the anisotropic conductive film. Also, it may be configured as follows: Like the anisotropic conductive film 1Db shown in FIG. 4B, the repeating unit 5 is inverted along the long-side direction and the short-side direction of the anisotropic conductive film. The repeating unit 5B of the shape repeats alternately.

Furthermore, for the above-mentioned anisotropic conductive film 1Ca, in order to reduce the number density of the short-side direction of the anisotropic conductive film, the difference between the repeating units 5 and 5B can be enlarged like the anisotropic conductive film 1Ea shown in FIG. 5A . The repeating columns in the longitudinal direction of the anisotropic conductive film are spaced apart from each other. In order to reduce the number density in the longitudinal direction of the anisotropic conductive film, the repeating unit 5 can be enlarged like the anisotropic conductive film 1Eb shown in FIG. 5B , 5B, the repeated columns in the width direction of the anisotropic conductive film are spaced apart from each other.

Also, as in the anisotropic conductive film 1F shown in FIG. 6 , the repeating pitch of the repeating unit 5 in the Y direction can be increased for the arrangement of conductive particles in the anisotropic conductive film 1A shown in FIG. 1A . In the configuration of the conductive particles 2 shown in FIG. 1A , each conductive particle 2 overlaps with any one of the vertices of the regular hexagons when the regular hexagons are arranged without gaps, but in the configuration of the conductive particles shown in FIG. 6 In the case where not all the conductive particles are arranged in a regular hexagon without gaps, the vertices of the regular hexagon are different from the arrangement of the conductive particles shown in FIG. 1A in this respect.

Also, like the anisotropic conductive film 1G shown in FIG. 7 , the repeating pitch in the Y direction can be further enlarged, and separate conductive particles 2p can be arranged between adjacent repeating units 5 in the Y direction, and other repeating units can also be further arranged. unit. Also, the repeating pitch of the repeating unit 5 in the X direction can be appropriately changed, and individual conductive particles or other repeating units can also be arranged between the repeating pitches in the X direction.

Also, like the anisotropic conductive film 1H shown in FIG. 8 , the trapezoidal repeating unit 5 or the repeating unit 5B formed by repeating the trapezoidal repeating unit 5 along the short-side direction or the long-side direction of the anisotropic conductive film, and A row of individual conductive particles 2p is disposed between the row of the anisotropic conductive film in the width direction of the repeating unit 5 and the row of the anisotropic conductive film of the repeating unit 5B in the width direction. Thereby, conductive particles 2 are arranged in an orthorhombic lattice, and individual conductive particles 2p exist in the center of the unit lattice. When the conductive particles are arranged in an orthorhombic lattice, in order to reduce the number density of the conductive particles, the repeating unit 5 itself can also be formed into a rhombus like the anisotropic conductive film 1I shown in FIG. 9 . By arranging the conductive particles 2 in an orthorhombic lattice as shown in FIGS. 8 and 9 , the conductive particles 2 exist in the long-side direction, short-side direction, and directions inclined relative to these directions of the anisotropic conductive film. Therefore, it becomes easy to achieve both the improvement of the capture property of the conductive particles and the suppression of the short circuit during the anisotropic conductive connection.

Also, it can also be arranged as follows: Like the anisotropic conductive film 1J shown in FIG. The rectangular lattice-like arrangement of the rhombus-shaped repeating unit 5B reversed along the long-side direction or the short-side direction of the anisotropic conductive film is repeated in such a manner that the lattice points do not overlap. As in the anisotropic conductive film 1K shown in FIG. 11, the same particle arrangement as that of the anisotropic conductive film 1J in FIG.

The repeating unit is not limited to the configuration in which the conductive particles occupy part of the vertices of the regular hexagon (that is, the lattice points of the hexagonal lattice) when the regular triangle is arranged without gaps. It may also be configured that the conductive particles occupy a part of the lattice points of the square lattice. For example, it is possible to alternately repeat the repeating unit 5 of the trapezoid along the long side direction and the short side direction of the anisotropic conductive film and the repeating unit 5B formed by inverting it, which is the same as the arrangement of the conductive particles shown in FIG. 5A. Arrangement As shown in FIG. 12, the anisotropic conductive film 1L is formed on lattice points of a square lattice.

Also, the number of vertices of the polygon forming the repeating unit is not limited to 4, and may be 5 or more, 6 or more, or 7 or more. However, in the design or production steps of manufacturing the anisotropic conductive film, in order to easily recognize the shape of the repeating unit, it is preferable to set the number of vertices of the repeating unit to an even number.

The shape of the polygon forming the repeating unit may or may not be a regular polygon, but it is preferably a shape having an axis of symmetry in terms of easily identifying the shape of the repeating unit. In this case, each conductive particle which comprises a repeating unit may not exist in the lattice point of a hexagonal lattice or a square lattice. For example, like the anisotropic conductive film 1M shown in FIG. 13 , the repeating unit 5 may be formed of conductive particles located at vertices of a regular octagon. The polygonal shape of the repeating unit can be determined according to the shape and pitch of the bumps or terminals for anisotropic conductive connection, the inclination angle of the long side direction of the bumps or terminals relative to the long side direction of the anisotropic conductive film, the different The resin composition of the insulating resin binder in the tropic conductive film is appropriately determined.

Furthermore, the arrangement of the conductive particles in the present invention is not limited to the arrangement of the repeating units shown in the drawings, for example, it may be formed by inclining the arrangement of the repeating units shown in the drawings. In this case, the aspect formed by inclining 90 degrees, that is, the long-side direction and the short-side direction of the exchange membrane is also included. Moreover, the thing which changed the interval between repeating units or the interval between the electroconductive particles in a repeating unit may be sufficient.

＜Shortest interparticle distance of conductive particles＞ The shortest interparticle distance of the conductive particles is preferably at least 0.5 times the average particle diameter of the conductive particles between adjacent conductive particles in a repeating unit and between adjacent conductive particles between repeating units. When this distance is too short, it will become easy to cause a short circuit by mutual contact of conductive particles. The upper limit of the distance between adjacent conductive particles is determined according to the bump shape or the bump pitch. For example, when the bump width is 200 μm and the inter-bump space is 200 μm, when at least one conductive particle exists in either the bump width or the inter-bump space, the shortest particle size of the conductive particles is The distance between them was set to less than 400 μm. It is preferable to set it as less than 200 micrometers from the viewpoint of making the capturing property of conductive particle reliable.

<Number Density of Conductive Particles> The number density of conductive particles is important in terms of suppressing the manufacturing cost of the anisotropic conductive film and avoiding excessive thrust of the pressing jig used for anisotropic conductive connection. When the average particle diameter of the conductive particles is less than 10 μm, it is preferably at most 50,000/mm ² , more preferably at most 35,000/mm ² , and still more preferably at most 30,000/mm ² . On the other hand, if the number density of the conductive particles is too small, there is a possibility that the terminals may not sufficiently catch the conductive particles and cause conduction failure, so it is preferably 300/mm ^or more, more preferably 500/mm ^or more, and then Preferably it is 800 pieces/mm ² or more.

Also, when the average particle diameter of the conductive particles is 10 μm or more, it is preferably at least 15 particles/mm ² , more preferably at least 50 particles/mm ² , and still more preferably at least 160 particles/mm ² . This is because the area ratio occupied by the conductive particles increases as the conductive particle diameter increases. For the same reason, it is preferably 1800 pieces/mm ² or less, more preferably 1100 pieces/mm ² or less, still more preferably 800 pieces/mm ² or less.

Furthermore, the number density of the conductive particles may deviate partially (as an example, 200 μm×200 μm) from the above number density.

＜Insulating resin adhesive＞ As the insulating resin adhesive 3 , thermally polymerizable compositions, photopolymerizable compositions, photothermally combined polymerizable compositions, and the like used as insulating resin adhesives in known anisotropic conductive films can be appropriately selected and used. Among them, examples of the thermally polymerizable composition include a thermally radically polymerizable resin composition containing an acrylate compound and a thermally radical polymerization initiator, and a thermally cationic polymerizable resin composition containing an epoxy compound and a thermally cationic polymerization initiator. Compositions, thermal anion polymerizable resin compositions containing epoxy compounds and thermal anionic polymerization initiators, etc., as photopolymerizable compositions include photoradical polymerization containing acrylate compounds and photoradical polymerization initiators Resin composition etc. A plurality of polymerizable compositions may be used in combination as long as no particular problem arises. Examples of combined use include combined use of a thermal cation polymerizable composition and a thermal radical polymerizable composition, and the like.

Here, as a photopolymerization initiator, multiple types of initiators that react to light having different wavelengths may be contained. Thereby, it is possible to distinguish the wavelengths used for photocuring of the resin constituting the insulating resin layer during production of the anisotropic conductive film and photocuring of the resin for bonding electronic components to each other when anisotropic conductive connection is used.

In the case of forming the insulating resin adhesive 3 using a photopolymerizable composition, all or all of the photopolymerizable compound contained in the insulating resin adhesive 3 can be cured by photocuring during the production of the anisotropic conductive film. Partially photohardened. By this photocuring, the arrangement of the conductive particles 2 in the insulating resin adhesive 3 can be maintained or fixed, and the suppression of short circuit and the improvement of capture are expected. Moreover, by adjusting the conditions of this photocuring, the viscosity of the insulating resin layer in the manufacturing process of an anisotropic conductive film can be adjusted.

The compounding quantity of the photopolymerizable compound in the insulating resin adhesive 3 is preferably 30 mass % or less, More preferably, it is 10 mass % or less, More preferably, it is less than 2 mass %. The reason for this is that when there are too many photopolymerizable compounds, the pushing force applied by press-fitting at the time of anisotropic conductive connection increases.

On the other hand, the thermally polymerizable composition contains a thermally polymerizable compound and a thermally polymerizable initiator, and as the thermally polymerizable compound, one that also functions as a photopolymerizable compound can be used. Moreover, you may contain a photopolymerizable compound separately in addition to a thermal polymerizable compound, and may contain a photopolymerizable initiator in a thermally polymerizable composition. It is preferable to contain a photopolymerizable compound and a photopolymerization initiator separately besides a thermopolymerizable compound. For example, a thermal cationic polymerization initiator is used as a thermal polymerization initiator, an epoxy resin is used as a thermal polymerizable compound, a photoradical initiator is used as a photopolymerization initiator, and an acrylate compound is used as a photopolymerizable compound. . Cured products of these polymeric compositions may also be contained in the insulating adhesive 3 .

As the acrylate compound used as a thermally or photopolymerizable compound, conventionally known thermally polymerizable (meth)acrylate monomers can be used. For example, a monofunctional (meth)acrylate monomer and a difunctional or higher polyfunctional (meth)acrylate monomer can be used.

In addition, the epoxy compound used as a polymerizable compound forms a three-dimensional network structure and imparts good heat resistance and adhesiveness. It is preferable to use a solid epoxy resin and a liquid epoxy resin in combination. Here, the term "solid epoxy resin" means an epoxy resin that is solid at normal temperature. In addition, the term "liquid epoxy resin" means an epoxy resin that is liquid at room temperature. In addition, normal temperature means the temperature range of 5-35 degreeC stipulated in JIS Z 8703. In this invention, 2 or more types of epoxy compounds can be used together. Moreover, an oxetane (oxetane) compound can also be used together besides an epoxy compound.

The solid epoxy resin is not particularly limited as long as it is compatible with the liquid epoxy resin and is solid at room temperature, and examples include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional epoxy resin Resins, dicyclopentadiene-type epoxy resins, novolac phenol-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, etc., may be used alone or in combination of two or more of them And use. Among these, bisphenol A type epoxy resin is preferably used.

The liquid epoxy resin is not particularly limited as long as it is liquid at room temperature, and examples thereof include bisphenol A epoxy resin, bisphenol F epoxy resin, novolak phenol epoxy resin, naphthalene epoxy resin, Resin etc. can be used individually by 1 type among these, or can use it in combination of 2 or more types. In particular, it is preferable to use a bisphenol A type epoxy resin from the viewpoint of film viscosity, flexibility, and the like.

Among the thermal polymerization initiators, examples of the thermal radical polymerization initiator include organic peroxides, azo compounds, and the like. In particular, an organic peroxide that does not generate nitrogen gas that causes air bubbles can be preferably used.

If the amount of the thermal radical polymerization initiator used is too small, hardening will become poor, and if too much, the product life (Life) will be reduced, so it is preferably 2 to 60 parts by mass relative to 100 parts by mass of the (meth)acrylate compound. parts by mass, more preferably 5 to 40 parts by mass.

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators of epoxy compounds can be used, for example, iodonium salts, permeic acid salts, phosphonium salts, ferrocenes, etc. that generate acids by heat can be used, In particular, aromatic cobaltium salts that exhibit good latency to temperature can be preferably used.

If the amount of thermal cationic polymerization initiator used is too small, the hardening tends to be poor, and if too much, the product life tends to be shortened. Therefore, it is preferably 2 to 60 parts by mass relative to 100 parts by mass of the epoxy compound, and more preferably 5 to 40 parts by mass.

As a thermal anionic polymerization initiator, a commonly used known one can be used. For example, organic acid dihydrazide, dicyandiamine, amine compound, polyamide amine compound, cyanate compound, phenolic resin, acid anhydride, carboxylic acid, tertiary amine compound, imidazole, Lewis acid, Brenest Acid salts, polythiol-based hardeners, urea resins, melamine resins, isocyanate compounds, blocked isocyanate compounds, and the like may be used alone or in combination of two or more. Among them, it is preferable to use a microcapsule type latent curing agent in which a modified imidazole is used as a core and the surface is coated with polyurethane.

It is preferable to contain a film-forming resin in the thermopolymerizable composition. The film-forming resin corresponds to, for example, a high-molecular-weight resin having an average molecular weight of 10,000 or more, and preferably has an average molecular weight of about 10,000 to 80,000 from the viewpoint of film-forming properties. As the film-forming resin, various resins such as phenoxy resins, polyester resins, polyurethane resins, polyester urethane resins, acrylic resins, polyimide resins, and butyral resins may be used alone or may be used alone. Use in combination of 2 or more types. Among these, a phenoxy resin is preferably suitably used from the viewpoint of the film formation state, connection reliability, and the like.

In order to adjust the melt viscosity, an insulating filler may also be contained in the thermopolymerizable composition. Examples thereof include silica powder, alumina powder, and the like. The size of the insulating filler is preferably 20 to 1000 nm in particle size, and the compounding amount is preferably 5 to 50 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable compound) such as an epoxy compound.

Furthermore, fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion catcher agents, etc. other than the above-mentioned insulating fillers may be contained.

Moreover, a stress relieving agent, a silane coupling agent, an inorganic filler, etc. can also be blended as needed. Examples of the stress relieving agent include hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-isoprene block copolymers, and the like. Moreover, examples of the silane coupling agent include epoxy-based, methacryloxy-based, amino-based, vinyl-based, mercapto/thioether-based, ureide-based, and the like. Moreover, as an inorganic filler, silica, talc, titanium oxide, calcium carbonate, magnesium oxide, etc. are mentioned.

The insulating resin adhesive 3 can be formed by forming a coating composition containing the above-mentioned resin into a film by a coating method, drying it, or further curing it, or forming a film by a known method in advance. The insulating resin adhesive 3 can also be obtained by laminating resin layers as needed. Also, the insulating resin adhesive 3 is preferably formed on a release film such as a polyethylene terephthalate film subjected to release treatment.

(Viscosity of insulating resin adhesive) The minimum melt viscosity of the insulating resin adhesive 3 can be appropriately determined according to the manufacturing method of the anisotropic conductive film and the like. For example, when a method of holding conductive particles in a specific arrangement on the surface of an insulating resin adhesive and pressing the conductive particles into the insulating resin adhesive is performed as a method of manufacturing an anisotropic conductive film, the In order to form the insulating resin adhesive into a film, it is preferable to set the minimum melt viscosity of the resin to 1100 Pa·s or more. Also, as described below, as shown in FIG. 14 or 15, a concave portion 3b is formed around the exposed portion of the conductive particle 2 pressed into the insulating resin adhesive 3, or as shown in FIG. In terms of forming the concave portion 3c directly above the conductive particles 2 pressed into the insulating resin adhesive 3, the minimum melt viscosity is preferably at least 1500 Pa·s, more preferably at least 2000 Pa·s, and still more preferably at least 2000 Pa·s. 3000-15000 Pa·s, preferably 3000-10000 Pa·s. Regarding the minimum melt viscosity, as an example, a rotary rheometer (manufactured by TA Instrument Co., Ltd.) can be used to keep it constant under the conditions of a temperature increase rate of 10°C/min and a measurement pressure of 5 g, using a measuring plate with a diameter of 8 mm And seek out. Also, when the step of pressing the conductive particles 2 into the insulating resin adhesive 3 is performed at preferably 40 to 80°C, more preferably at 50 to 60°C, the concave portion 3b or 3c is formed in the same manner as above. On the other hand, the lower limit of the viscosity at 60°C is preferably not less than 3000 Pa·s, more preferably not less than 4000 Pa·s, still more preferably not less than 4500 Pa·s, and the upper limit is preferably not more than 20000 Pa·s. More preferably, it is 15000 Pa·s or less, More preferably, it is 10000 Pa·s or less.

By making the viscosity of the resin constituting the insulating resin adhesive 3 high as described above, when an anisotropic conductive film is used, the conductive particles 2 are sandwiched between opposing electronic parts and other connection objects. When heat and pressure are applied, the conductive particles 2 in the anisotropic conductive film can be prevented from flowing away due to the flow of the molten insulating resin binder 3 .

(thickness of insulating resin adhesive) The thickness La of the insulating resin adhesive 3 is preferably not less than 1 μm and not more than 60 μm, more preferably not less than 1 μm and not more than 30 μm, still more preferably not less than 2 μm and not more than 15 μm. Moreover, it is preferable that the ratio (La/D) of the thickness La of the insulating resin adhesive 3 and the average particle diameter D of the conductive particle 2 is 0.6-10. When the thickness La of the insulating resin adhesive 3 is too large, the conductive particles are likely to be dislocated during the anisotropic conductive connection, and the catchability of the conductive particles in the terminal is reduced. This tendency becomes remarkable when La/D exceeds 10. Therefore, La/D is preferably 8 or less, more preferably 6 or less. Conversely, if the thickness La of the insulating resin adhesive 3 is too small and La/D is less than 0.6, it is difficult to maintain the conductive particles in a specific particle dispersion state or specific arrangement by the insulating resin adhesive 3 . Especially when the terminal to be connected is a high-density COG, the ratio (La/D) of the layer thickness La of the insulating resin adhesive 3 to the particle diameter D of the conductive particles 2 is preferably 0.8-2.

(Embedded state of conductive particles in insulating resin binder) There is no particular limitation on the embedding state of the conductive particles 2 in the insulating resin adhesive 3, and the anisotropic conductive connection is performed by sandwiching an anisotropic conductive film between opposing parts and applying heat and pressure. In this case, it is preferable to expose a part of the conductive particles 2 from the insulating resin adhesive 3 as shown in FIGS. tangent plane 3p of the conductive particle 2 to form a recess 3b around the exposed portion of the conductive particle 2, or as shown in FIG. Partly, the concave portion 3c is formed with respect to the tangential plane 3p similar to the above, and the surface of the insulating resin adhesive 3 directly above the conductive particle 2 has undulations. For the flattening of the conductive particles 2 generated when the conductive particles 2 are clamped between the electrodes of the facing electronic parts and heated and pressed, by the presence of the concave portion 3b as shown in Fig. 14 and Fig. 15 and the absence of the concave portion 3b In comparison, the resistance of the conductive particles 2 from the insulating resin binder 3 is reduced. Therefore, it becomes easy to pinch the conductive particle 2 between the opposing electrodes, and conduction performance also improves. In addition, in the resin constituting the insulating resin adhesive 3, by forming the concave portion 3c (FIG. 16) on the surface of the resin directly above the conductive particle 2, the pressure during heating and pressing changes compared with the case where the concave portion 3c does not exist. It is easy to concentrate on the conductive particles 2, and the conductive particles 2 are easily held in the electrode, and the conduction performance is improved.

In terms of easily obtaining the effect of the above-mentioned recesses 3b, 3c, the ratio of the maximum depth Le of the recess 3b (Figure 14, Figure 15) around the exposed portion of the conductive particle 2 to the average particle diameter D of the conductive particle 2 (Le /D) is preferably less than 50%, more preferably less than 30%, and more preferably 20 to 25%. The maximum diameter Ld of the concave portion 3b (Fig. 14, Fig. 15) around the exposed portion of the conductive particle 2 and The ratio (Ld/D) of the average particle diameter D of the conductive particles 2 is preferably 100% or more, more preferably 100 to 150%, and the maximum depth Lf of the resin recess 3c ( FIG. The ratio (Lf/D) of the average particle diameter D of the conductive particles 2 is preferably greater than 0, and is preferably less than 10%, more preferably less than 5%.

Furthermore, the diameter Lc of the exposed portion of the conductive particles 2 can be set to be below the average particle diameter D of the conductive particles 2 , preferably 10-90% of the particle diameter D. One point of the top 2t of the conductive particle 2 may be exposed, or the conductive particle 2 may be completely embedded in the insulating resin adhesive 3 so that the diameter Lc becomes zero.

(The position of the conductive particles in the thickness direction of the insulating resin adhesive) In terms of easily obtaining the effect of the above-mentioned concave portion 3b, the ratio of the distance Lb between the tangent plane 3p and the deepest part of the conductive particle 2 (hereinafter referred to as the embedding amount) to the average particle diameter D of the conductive particle 2 (Lb/D) (hereinafter referred to as embedding rate) is preferably not less than 60% and not more than 105%.

＜Insulating Adhesive Layer＞ In the anisotropic conductive film of the present invention, an insulating adhesive layer 4 having a viscosity or adhesiveness different from that of the resin constituting the insulating resin adhesive 3 may be laminated on the insulating resin adhesive 3 on which the conductive particles 2 are disposed.

In the case where the above-mentioned concave portion 3b is formed on the insulating resin adhesive 3, the insulating adhesive layer 4 can be laminated on the insulating resin adhesive 3 where the concave portion 3b is formed, like the anisotropic conductive film 1d shown in FIG. The surface, like the anisotropic conductive film 1e shown in FIG. 18, may be laminated on the surface opposite to the surface on which the concave portion 3b is formed. The same applies to the case where the insulating resin adhesive 3 is formed with the concave portion 3c. By laminating the insulating adhesive layer 4, when the anisotropic conductive film is used to connect the electronic parts with anisotropic conduction, the space formed by the electrodes or bumps of the electronic parts can be filled, and the adhesiveness can be improved.

Also, when the insulating adhesive layer 4 is laminated on the insulating resin adhesive 3, it is preferable that the insulating adhesive layer 4 is located on the IC chip regardless of whether the insulating adhesive layer 4 is located on the formation surface of the recesses 3b, 3c. The first electronic component side (in other words, the insulating resin adhesive 3 is located on the second electronic component side such as the substrate). Thereby, the inadvertent movement of the conductive particles can be avoided, and the trapping property can be improved. Furthermore, generally, the first electronic component such as an IC chip is set to the side of the pressing jig, the second electronic component such as the substrate is set to the side of the stage, and after the anisotropic conductive film and the second electronic component are temporarily pressure-bonded, the first The electronic part and the second electronic part are formally crimped, but according to the size of the thermocompression bonding area of the second electronic part, etc., after the anisotropic conductive film is temporarily pasted on the first electronic part, the first electronic part and the second Electronic parts are officially crimped.

As the insulating adhesive layer 4, what is used as an insulating adhesive layer among well-known anisotropic conductive films can be selected suitably and used. The insulating adhesive layer 4 may use the same resin as the above-mentioned insulating resin adhesive 3 and further adjust the viscosity to a lower one. The greater the difference between the minimum melt viscosity of the insulating adhesive layer 4 and the insulating resin adhesive 3, the easier it is to fill the space formed by the electrodes or bumps of the electronic parts with the insulating adhesive layer 4, and it is expected to improve the mutual contact between the electronic parts. Subsequent effects. Moreover, the more this difference exists, the relatively smaller the amount of movement of the resin constituting the insulating resin adhesive 3 during anisotropic conductive connection is, and therefore the easier it is to improve the capture property of the conductive particles of the terminal. Practically speaking, the minimum melt viscosity ratio between the insulating adhesive layer 4 and the insulating resin adhesive 3 is preferably 2 or higher, more preferably 5 or higher, and still more preferably 8 or higher. On the other hand, if the ratio is too large, when the long-sized anisotropic conductive film is made into a package, resin overflow or blocking (blocking) may occur, so 15 is practically preferable. the following. More specifically, the preferred minimum melt viscosity of the insulating adhesive layer 4 satisfies the above ratio and is 3000 Pa·s or less, more preferably 2000 Pa·s or less, and most preferably 100 to 2000 Pa·s.

As a method of forming the insulating adhesive layer 4, a coating composition containing the same resin as that used to form the insulating resin adhesive 3 can be formed into a film by a coating method and dried, or further hardened, or preliminarily Film formation is performed by a known method.

The thickness of the insulating adhesive layer 4 is preferably not less than 1 μm and not more than 30 μm, more preferably not less than 2 μm and not more than 15 μm.

Furthermore, the minimum melt viscosity of the overall anisotropic conductive film formed by combining the insulating resin adhesive 3 and the insulating adhesive layer 4 also depends on the ratio of the thicknesses of the insulating resin adhesive 3 and the insulating adhesive layer 4. It may be 8000 Pa·s or less, and may be 200 to 7000 Pa·s, preferably 200 to 4000 Pa·s for easy filling between bumps.

Furthermore, insulating fillers such as silica microparticles, alumina, and aluminum hydroxide may be added to the insulating resin adhesive 3 or the insulating adhesive layer 4 as needed. It is preferable that the compounding quantity of an insulating filler shall be 3 mass parts or more and 40 mass parts or less with respect to 100 mass parts of resins which comprise these layers. Thereby, even if the anisotropic conductive film is melted during the anisotropic conductive connection, unnecessary movement of the conductive particles due to the melted resin can be suppressed.

＜Manufacturing method of anisotropic conductive film＞ As a method of producing an anisotropic conductive film, for example, a transfer mold for arranging conductive particles in a specific arrangement is produced, conductive particles are filled in the concave portion of the transfer mold, and the insulating resin adhesive formed on the release film 3 is covered thereon and pressure is applied, and the conductive particles 2 are pressed into the insulating resin adhesive 3 , so that the conductive particles 2 are transferred to the insulating resin adhesive 3 . Or further, the insulating adhesive layer 4 is laminated on the conductive particles 2 . In this way, the anisotropic conductive film 1A was obtained.

In addition, after filling the conductive particles in the concave part of the transfer mold, the insulating resin adhesive is covered on it, and the conductive particles are transferred from the transfer mold to the surface of the insulating resin adhesive, and the conductive particles on the insulating resin adhesive are transferred to the surface of the insulating resin adhesive. The particles are pressed into the insulating resin binder, so that the anisotropic conductive film can also be produced. The embedding amount (Lb) of the conductive particles can be adjusted by the pressing force, temperature, etc. at the time of this pressing. In addition, the shape and depth of the recesses 3b, 3c can be adjusted by the viscosity of the insulating resin adhesive during press-fitting, the press-in speed, temperature, and the like. For example, the lower limit of the viscosity of the insulating resin adhesive when the conductive particles are pressed in is preferably at least 3000 Pa·s, more preferably at least 4000 Pa·s, still more preferably at least 4500 Pa·s, and the upper limit is set to It is preferably at most 20000 Pa·s, more preferably at most 15000 Pa·s, further preferably at most 10000 Pa·s. Moreover, such viscosity can be obtained at preferably 40-80°C, more preferably 50-60°C. More specifically, in the case of manufacturing the anisotropic conductive film 1a having the recess 3b shown in FIG. 14 on the surface of the insulating resin adhesive, it is preferable to set the viscosity of the insulating resin adhesive when the conductive particles are pressed 8000 Pa·s (50-60°C), in the case of manufacturing the anisotropic conductive film 1c having the concave portion 3c shown in Figure 16, it is preferable to set the viscosity of the insulating resin adhesive when the conductive particles are pressed into It is 4500 Pa s (50 ~ 60 ℃).

In addition, as a transfer mold, besides what filled the concave part with conductive particles, the thing which provided the top surface of a convex part with a microadhesive, and made conductive particle adhere to this top surface can also be used.

These transfer molds can be manufactured by using or applying known techniques such as machining, photolithography, and printing.

In addition, as a method of arranging conductive particles in a specific arrangement, a method using a biaxially stretched film or the like may be used instead of a method using a transfer mold.

＜Package＞ In order to continuously supply the anisotropic conductive film for the connection of electronic parts, it is preferable to make a film package wound on a reel. The length of the film package may be at least 5 m, preferably at least 10 m. There is no upper limit in particular, but it is preferably not more than 5000 m, more preferably not more than 1000 m, and still more preferably not more than 500 m in terms of the operability of the cargo.

The film package may be formed by connecting anisotropic conductive films shorter than the full length with connecting tapes. There may be many connecting parts, and they may exist regularly or randomly. The thickness of the connecting tape is not particularly limited as long as it does not impede the performance, but if it is too thick, it will affect the overflow or adhesion of the resin, so it is preferably 10-40 μm. Moreover, the width of a film is not specifically limited, As an example, it is 0.5-5 mm.

According to the film package, continuous anisotropic conductive connection can be realized, which helps to reduce the cost of the connection body.

＜Connection structure＞ The anisotropic conductive film of the present invention is used for anisotropic first electronic parts such as FPC, IC chip, IC module and second electronic parts such as FPC, rigid substrate, ceramic substrate, glass substrate and plastic substrate by heat or light. It can be better applied when the conductive connection is made. In addition, IC chips or IC modules may be stacked to anisotropically connect the first electronic components. The bonded structure thus obtained and the method for its manufacture are also part of the present invention.

As a method of connecting electronic components using an anisotropic conductive film, it is preferable to temporarily stick the interface of the anisotropic conductive film on the side where the conductive particles in the film thickness direction are present, for example, in order to improve connection reliability. For the second electronic component such as the wiring board, the first electronic component such as the IC chip is mounted on the temporary anisotropic conductive film, and thermocompression bonding is performed from the side of the first electronic component. Moreover, it is also possible to connect by photocuring. Furthermore, in this connection, it is preferable to align the long-side direction of the terminal of the electronic component with the short-side direction of the anisotropic conductive film from the viewpoint of connection work efficiency. Example

Experimental example 1 to experimental example 8 (Production of anisotropic conductive film) Regarding the anisotropic conductive film used for COG connection, the effects of the resin composition of the insulating resin adhesive and the arrangement of conductive particles on the film-forming performance and conduction characteristics were studied in the following manner.

First, resin compositions for forming an insulating resin adhesive and an insulating adhesive layer were prepared with the compositions shown in Table 1, respectively. In this case, the minimum melt viscosity of the resin composition is adjusted according to the preparation conditions of the insulating resin composition. The resin composition forming the insulating resin adhesive was coated on a PET film with a film thickness of 50 μm by a bar coater, and dried in an oven at 80°C for 5 minutes, and the resin composition shown in Table 2 was formed on the PET film. An insulating resin adhesive layer with a thickness La. In the same manner, an insulating adhesive layer was formed on the PET film with the thickness shown in Table 2.

[Table 1] (parts by mass) Composition table for COG composition A B C D. insulating resin adhesive Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 50 45 40 37 Silica filler (Aerosil R805, Japan Aerosil Co., Ltd.) 20 10 10 8 Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 25 40 45 50 Silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.) 2 2 2 2 Thermal cationic polymerization initiator (SI-60L, Sanxin Chemical Industry Co., Ltd.) 3 3 3 3 insulating adhesive layer Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 40 Silica filler (Aerosil R805, Japan Aerosil Co., Ltd.) 5 Liquid epoxy resin (jER828, Mitsubishi Chemical Corporation) 50 Silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.) 2 Thermal cationic polymerization initiator (SI-60L, Sanxin Chemical Industry Co., Ltd.) 3

Next, a mold was produced so that the arrangement of the conductive particles in plan view would be the arrangement shown in Table 2, and the distance between the centers of the closest conductive particles in the repeating unit would be 6 μm. Pellets of a known transparent resin were poured into the mold in a molten state, cooled and solidified, thereby forming a resin mold in which the concave portions were arranged as shown in Table 2. Here, in Experimental Example 8, the conductive particles were arranged in a hexagonal lattice (number density: 32,000/mm ² ), and one of the lattice axes was inclined by 15° relative to the long-side direction of the anisotropic conductive film. °.

Prepare metal-coated resin particles (Sekisui Chemical Co., Ltd., AUL703, average particle size: 3 μm) as conductive particles, fill the conductive particles into the concave portion of the resin mold, and coat the above-mentioned insulating resin adhesive thereon, Bonding was carried out by pressing at 60° C. and 0.5 MPa. Then, the insulating resin adhesive is peeled off from the mold, and the conductive particles on the insulating resin adhesive are pressed (pressing conditions: 60-70°C, 0.5 Mpa), thereby pressing them into the insulating resin adhesive , a film in which conductive particles were embedded in an insulating resin binder in the state shown in Table 2 was produced. In this case, the embedding state of the conductive particles is controlled according to the pressing conditions. As a result, in Experimental Example 4, the film shape was not maintained after the conductive particles were injected, but in other experimental examples, a film in which the conductive particles were embedded could be produced. In observation with a metal microscope, as shown in Table 2, recesses were observed around the exposed portion of the embedded conductive particles or directly above the embedded conductive particles. Furthermore, both the concave portion around the exposed portion of the conductive particle and the concave portion directly above the conductive particle were observed in each experimental example except Experimental Example 4, and the most clearly observed is shown in Table 4 for each experimental example. The measured value of the concave part.

An anisotropic conductive film in which the resin layer is a two-layer type is produced by laminating an insulating adhesive layer on the conductive particle embedded film side. However, in Experimental Example 4, the film shape was not maintained after the conductive particles were injected, so the following evaluation was not performed.

(Evaluation) For the anisotropic conductive film of each experimental example, (a) initial on-resistance and (b) on-reliability were measured as follows. The results are shown in Table 2.

(a) Initial on-resistance The anisotropic conductive film of each experimental example was sandwiched between the glass substrate on the stage and the IC for conducting characteristics evaluation on the pressing tool side, and the pressing tool was heated and pressed (180°C, 5 seconds) to obtain each evaluation. Use connectors. In this case, the thrust obtained by the pressing tool was changed to three levels of low (40 MPa), medium (60 MPa), and high (80 MPa), and three types of connection objects for evaluation were obtained.

Here, regarding the IC for conduction characteristic evaluation and the glass substrate, their terminal patterns correspond, and the dimensions are as follows. In addition, when connecting the evaluation IC and the glass substrate, the long-side direction of the anisotropic conductive film was aligned with the short-side direction of the bump.

IC for evaluation of conduction characteristics Dimensions: 1.8×20.0mm Thickness: 0.5mm Bump specifications: size 30×85 μm, distance between bumps 50 μm, bump height 15 μm

Glass substrate (ITO wiring) Glass material: 1737F manufactured by Corning Incorporated Dimensions: 30×50 mm Thickness: 0.5 mm Electrode: ITO wiring

The initial on-resistance of the connection object for evaluation obtained by measurement is evaluated in accordance with the following three-stage evaluation criteria. Evaluation criteria for initial on-resistance (practical, as long as it does not reach 2 Ω, there is no problem) A: Less than 0.4 Ω B: 0.4 Ω or more and less than 0.8 Ω C: 0.8Ω or more

(b) Conduction reliability Conduct a reliability test in which the evaluation connector made in (a) is placed in a constant temperature bath at a temperature of 85°C and a humidity of 85%RH for 500 hours, and measure the on-resistance after the initial on-resistance in the same way as the initial on-resistance according to the following three Evaluate according to the evaluation criteria of each stage.

Evaluation criteria for conduction reliability (practical, as long as it does not reach 5 Ω, there is no problem) A: Less than 1.2 Ω B: 1.2 Ω or more and less than 2 Ω C: 2Ω or more

[Table 2] COG evaluation Experimental example 1 Experimental example 2 Experimental example 3 Experimental example 4 Experimental example 5 Experimental example 6 Experimental example 7 Experimental example 8 Composition of resin A B C D. A A A A The shape of the film after the conductive particles are pressed OK OK OK NG OK OK OK OK Conductive particle size: D (μm) 3 3 3 3 3 3 3 3 Configuration of Conductive Particles Figure 1A Figure 1A Figure 1A Figure 1A Figure 4A Figure 8 Figure 10 hexagonal lattice The distance between the centers of the closest conductive particles (μm) 6 6 6 6 6 6 6 6 Thickness (μm) Insulating resin adhesive layer (La) 4 4 4 4 4 4 4 4 insulating adhesive layer 14 14 14 14 14 14 14 14 La/D 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Minimum Melt Viscosity (Pa·s) Insulating resin adhesive layer 8000 2000 1500 800 8000 8000 8000 8000 insulating adhesive layer 800 800 800 800 800 800 800 800 Total Melt Viscosity 1200 900 900 800 1200 1200 1200 1200 Viscosity at 60°C (Pa·s) Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Embedded State of Conductive Particles Embedding rate (100×Lb/D)% >80 >95 >95 - >80 >80 >80 >80 Exposure diameter Lc (μm) <2.8 <2.5 <2.5 - <2.8 <2.8 <2.8 <2.8 presence or absence of concave part have have have - have have have have The maximum depth Le of the concave part (ratio to the particle size D of conductive particles) <50% <50% <50% - <50% <50% <50% <50% The maximum diameter Ld of the concave portion (ratio to the particle diameter D of conductive particles) <1.3 <1.3 <1.3 - <1.3 <1.3 <1.3 <1.3 Evaluation Thrust: Low 40 MPa Initial on-resistance A A A - A A A B Conduction reliability A A A - A A A B Thrust: medium 60 MPa Initial on-resistance A A A - A A A B Conduction reliability A A A - A A A B Thrust: up to 80 MPa Initial on-resistance A A A - A A A A Conduction reliability A A A - A A A A

As can be seen from Table 2, in Experimental Example 4 in which the minimum melt viscosity of the insulating resin layer was 800 Pa·s, it was difficult to form a film having recesses in the insulating resin adhesive near the conductive particles. On the other hand, in the experimental example in which the minimum melt viscosity of the insulating resin adhesive is 1500 Pa·s or more, by adjusting the conditions at the time of embedding the conductive particles, it can be formed near the conductive particles of the insulating resin adhesive. The anisotropic conductive film obtained in this way has good conduction characteristics when used in COG. Also, compared with Experimental Example 8 in which the hexagonal lattice is arranged, in Experimental Examples 1 to 7 in which the number density of conductive particles is lower, anisotropic conductive connection can be performed under lower pressure.

(c) Short circuit occurrence rate Using the anisotropic conductive films of Experimental Examples 1-3 and 5-8, using ICs for evaluation of the following short-circuit occurrence rates, the connection objects for evaluation were obtained under the connection conditions of 180°C, 60 MPa, and 5 seconds, and the obtained results were measured. For the number of short circuits in the evaluation connectors, the occurrence rate of short circuits was calculated as the ratio of the measured number of short circuits to the number of terminals of the evaluation IC.

IC for evaluation of short circuit occurrence rate (comb TEG (test element group, test element group) with 7.5 μm space: Dimensions: 15×13mm Thickness: 0.5 mm Bump specifications: size 25×140 μm, distance between bumps 7.5 μm, bump height 15 μm

As long as the short circuit is less than 50 ppm, it is practically better, and the anisotropic conductive films of Experimental Examples 1-3 and 5-8 are all less than 50 ppm.

Furthermore, for each of the experimental examples except the experimental example 4, the conductive particles captured by each bump were measured, and as a result, 10 or more conductive particles were captured.

Experimental example 9-16 (Production of anisotropic conductive film) Regarding the anisotropic conductive film used for FOG connection, the effects of the resin composition of the insulating resin adhesive and the arrangement of the conductive particles on the film formation performance and conduction characteristics were studied in the following manner.

That is, a resin composition for forming an insulating resin adhesive and an insulating adhesive layer was prepared with the composition shown in Table 3, and an anisotropic conductive film was produced in the same manner as in Experimental Example 1 using these. Table 4 shows the arrangement of the conductive particles in this case and the distance between the centers of the closest conductive particles. In Experimental Example 16, the conductive particles were arranged in a hexagonal lattice (number density: 15,000/mm ² ), and one of the lattice axes was inclined at 15° with respect to the long side direction of the anisotropic conductive film.

In the manufacturing process of the anisotropic conductive film, after the conductive particles were pressed into the insulating resin binder, the film shape was not maintained in Experimental Example 12, but the film shape was maintained in the other experimental examples. Therefore, regarding the anisotropic conductive films of the experimental examples other than the experimental example 12, the embedding state of the conductive particles was observed and measured with a metal microscope, and the following evaluation was performed. Table 4 shows the embedding state of the conductive particles in each experimental example. The embedding state shown in Table 4 is the same as Table 2, and is a measured value in which the recessed part of the insulating resin adhesive was observed most clearly about each experimental example.

(Evaluation) For the anisotropic conductive film of each experimental example, (a) initial on-resistance and (b) on-reliability were measured as follows. The results are shown in Table 4.

(a) Initial on-resistance The anisotropic conductive film obtained in each experiment example was cut into 2 mm×40 mm, sandwiched between the FPC for evaluation of conduction characteristics and the glass substrate, and heated and pressed with a tool width of 2 mm (180°C, 5 seconds) , to obtain the linkers for evaluation. In this case, the thrust obtained by the pressing tool was changed to three levels of low (3 MPa), medium (4.5 MPa), and high (6 MPa), and three types of connection objects for evaluation were obtained. The on-resistance of the connection object for evaluation obtained was measured similarly to Experimental Example 1, and the measured value was evaluated in three stages according to the following reference|standard.

FPC for evaluation: Terminal pitch: 20 μm Terminal width/space between terminals: 8.5 μm/11.5 μm Polyimide film thickness (PI) / copper foil thickness (Cu) = 38/8, tin plating (Sn plating)

Alkali-free glass substrate: Electrode: ITO wiring Thickness: 0.7 mm

Evaluation criteria for initial on-resistance A: Less than 1.6 Ω B: 1.6 Ω or more and less than 2.0 Ω C: 2.0Ω or more

(b) Conduction reliability The connection object for evaluation prepared in (a) was placed in a constant temperature bath at a temperature of 85°C and a humidity of 85%RH for 500 hours, and the on-resistance after measurement was performed in the same way as the initial on-resistance, and the evaluation was performed in three stages according to the following criteria. Measurements.

Evaluation Criteria for Conduction Reliability A: Less than 3.0 Ω B: 3.0 Ω or more and less than 4 Ω C: 4.0Ω or more

As can be seen from Table 4, in Experimental Example 12 in which the minimum melt viscosity of the insulating resin layer was 800 Pa·s, it was difficult to form a film having recesses. On the other hand, in the experimental example in which the minimum melt viscosity of the insulating resin layer is 1500 Pa·s or more, by adjusting the conditions at the time of embedding the conductive particles, it is possible to form a recess near the conductive particles of the insulating resin binder , and the anisotropic conductive film obtained in this way has good conduction characteristics when used in FOG.

(c) Short circuit occurrence rate Measure the number of short circuits of the evaluation connectors whose initial on-resistance has been measured, and calculate the occurrence rate of short circuits based on the measured number of short circuits and the number of gaps between the evaluation connectors. As long as the short-circuit occurrence rate does not reach 100 ppm, there is no practical problem. The occurrence rates of short circuits in Experimental Examples 9-11 and 13-16 did not reach 100 ppm.

Furthermore, for each experimental example except experimental example 12, the conductive particles captured by each bump were measured, and as a result, 10 or more conductive particles were captured.

[Table 3] (parts by mass) Composition table for FOG composition E. f G h insulating resin adhesive Phenoxy resin (YP-50, Nippon Steel Sumitomo Chemical Co., Ltd.) 55 45 25 5 Phenoxy resin (FX-316ATM55, Nippon Steel & Sumikin Chemical Co., Ltd.) 20 40 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Co., Ltd.) 20 20 20 20 2-functional acrylate oligomer (UN-9200A, Negami Industrial Co., Ltd.) 25 35 35 35 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 1 1 1 Phosphomethacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 1 1 1 Benzoyl peroxide (Nyper BW, NOF Corporation) 5 5 5 5 insulating adhesive layer Phenoxy resin (FX-316ATM55, Nippon Steel & Sumikin Chemical Co., Ltd.) 50 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Co., Ltd.) 20 2-functional acrylate oligomer (UN-9200A, Negami Industrial Co., Ltd.) 30 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 Phosphomethacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 Benzoyl peroxide (Nyper BW, NOF Corporation) 5

[Table 4] FOG evaluation Experimental example 9 Experiment 10 Experiment 11 Experiment 12 Experiment 13 Experiment 14 Experiment 15 Experiment 16 Composition of resin E. f G h E. E. E. E. The shape of the film after the conductive particles are pressed OK OK OK NG OK OK OK OK Conductive particle size: D (μm) 3 3 3 3 3 3 3 3 Configuration of Conductive Particles Figure 1A Figure 1A Figure 1A Figure 1A Figure 4A Figure 9 Figure 11 hexagonal lattice The distance between the centers of the closest conductive particles (μm) 9 9 9 9 9 9 9 9 Thickness (μm) Insulating resin adhesive layer (La) 4 4 4 4 4 4 4 4 insulating adhesive layer 14 14 14 14 14 14 14 14 La/D 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Minimum Melt Viscosity (Pa·s) Insulating resin adhesive layer 8000 2000 1500 800 8000 8000 8000 8000 insulating adhesive layer 800 800 800 800 800 800 800 800 Total Melt Viscosity 1200 900 900 800 1200 1200 1200 1200 Viscosity at 60°C (Pa·s) Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Embedded State of Conductive Particles Embedding rate (100×Lb/D)% >80 >95 >95 - >80 >80 >80 >80 Exposure diameter Lc (μm) <2.8 <2.5 <2.5 - <2.8 <2.8 <2.8 <2.8 presence or absence of concave part have have have - have have have have The maximum depth Le of the concave part (ratio to the particle size D of conductive particles) <50% <50% <50% - <50% <50% <50% <50% The maximum diameter Ld of the concave part (ratio to the particle diameter D of conductive particles) <1.3 <1.3 <1.3 - <1.3 <1.3 <1.3 <1.3 Evaluation Thrust: Low 3 MPa Initial on-resistance A A A - A A A B Conduction reliability A A A - A A A B Thrust: medium 4.5 MPa Initial on-resistance A A A - A A A B Conduction reliability A A A - A A A B Thrust: up to 6 MPa Initial on-resistance A A A - A A A A Conduction reliability A A A - A A A A

1A, 1Ba, 1Bb, 1Ca, 1Cb, 1Da, 1Db, 1Ea, 1Eb, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M, 1a, 1b, 1c, 1d, 1e: Anisotropic conductive film 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2p, 2q, 2r, 2s, 2t, 2u: conductive particles 3: Insulating resin adhesive 4: Insulating adhesive layer 5, 5B: repeat unit

[FIG. 1A] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1A of an Example. [FIG. 1B] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1A of an Example. [ Fig. 1C ] is a cross-sectional view of an anisotropic conductive film 1A of an embodiment. [FIG. 2A] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Ba of an Example. [FIG. 2B] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Bb of an Example. [FIG. 3A] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Ca of an Example. [FIG. 3B] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Cb of an Example. [FIG. 4A] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Da of an Example. [FIG. 4B] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Db of an Example. [FIG. 5A] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Ea of an Example. [FIG. 5B] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1Eb of an Example. [FIG. 6] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1F of an Example. [FIG. 7] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1G of an Example. [FIG. 8] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1H of an Example. [FIG. 9] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1I of Example. [FIG. 10] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1J of an Example. [FIG. 11] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1K of an Example. [FIG. 12] It is a top view explaining the arrangement|positioning of the conductive particle of 1 L of anisotropic conductive films of an Example. [FIG. 13] It is a top view explaining the arrangement|positioning of the conductive particle of the anisotropic conductive film 1M of an Example. [ Fig. 14 ] is a cross-sectional view of an anisotropic conductive film 1a of an example. [ Fig. 15 ] is a cross-sectional view of the anisotropic conductive film 1b of the embodiment. [ Fig. 16 ] is a cross-sectional view of the anisotropic conductive film 1c of the embodiment. [ Fig. 17 ] is a cross-sectional view of the anisotropic conductive film 1d of the embodiment. [ Fig. 18 ] is a cross-sectional view of an anisotropic conductive film 1e of an example.

Claims (17)

An anisotropic conductive film, in which conductive particles are arranged in an insulating resin binder, and polygonal repeating units are repeatedly arranged in a plan view, and the polygonal repeating units are formed by sequentially connecting the centers of a plurality of conductive particles Formed, the polygon of the repeating unit has sides oblique to the long-side direction or the short-side direction of the anisotropic conductive film, adjacent repeating units are repeatedly inverted, and adjacent repeating units are reversed with spaces between them. An anisotropic conductive film, in which conductive particles are arranged in an insulating resin binder, and polygonal repeating units are repeatedly arranged in a plan view, and the polygonal repeating units are formed by sequentially connecting the centers of a plurality of conductive particles Formed, the polygon of the repeating unit has sides oblique to the long-side direction or the short-side direction of the anisotropic conductive film, and the repeating pitch of the repeating unit is enlarged. The anisotropic conductive film according to claim 1 or 2, wherein the repeating unit is arranged on one side of the anisotropic conductive film. The anisotropic conductive film according to claim 1 or 2, wherein the repeating unit is trapezoidal. The anisotropic conductive film according to claim 1 or 2, wherein each side of the polygon forming the repeating unit is oblique to the long-side direction or short-side direction of the anisotropic conductive film. The anisotropic conductive film according to claim 1 or 2, wherein the polygons forming the repeating unit have sides in the long direction or short direction of the anisotropic conductive film. The anisotropic conductive film according to claim 1 or 2, wherein, when the polygon is reversed with one side of the polygon constituting the repeating unit as the center, one side of the polygon of the repeating unit after inversion and Adjacent repeating units overlap on one side before inversion. The anisotropic conductive film as claimed in claim 1 or 2, wherein the conductive particle units are formed with positive multiplicity part of an angle. The anisotropic conductive film according to claim 1 or 2, wherein the arrangement of the conductive particles constituting the conductive particle unit overlaps with vertices of the hexagons when regular hexagons are arranged without gaps. The anisotropic conductive film according to claim 1 or 2, wherein individual conductive particles are arranged between the repeating units. The anisotropic conductive film according to claim 1 or 2, wherein a row of individual conductive particles is disposed between the repeating units. The anisotropic conductive film according to claim 1 or 2, wherein the repeating unit is a rhombus. The anisotropic conductive film according to claim 1 or 2, wherein the conductive particles are metal particles or metal-coated resin particles. The anisotropic conductive film according to claim 1 or 2, wherein the surface of the conductive particles is coated. The anisotropic conductive film according to claim 1 or 2, which is laminated with a resin adhesive layer. A connection structure, which anisotropically connects a first electronic component and a second electronic component through the anisotropic conductive film according to any one of claims 1 to 15. A method for manufacturing a connection structure, which manufactures a connection structure between a first electronic component and a second electronic component by thermocompression bonding the first electronic component and the second electronic component through an anisotropic conductive film, and uses the request The anisotropic conductive film of any one of items 1 to 15 as the anisotropic conductive film.

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