TW202233787A - Anisotropic conductive film - Google Patents

Abstract

To provide an anisotropic conductive film capable of corresponding to a bump of a narrow pitch and reducing number density of conductive particles more than that of a conventional anisotropic conductive film. Disclosed is an anisotropic conductive film 1A in which a conductive particle 2 is arranged in an insulating resin binder 3. A polygon repeating unit 5 formed by sequentially connect the centers of a plurality of conductive particle 2 is repeatedly arranged in vertical and horizontal directions in a plan view. A polygon side of the repeating unit 5 obliquely crosses the longitudinal direction or the transverse direction of the anisotropic conductive film.

Description

Anisotropic Conductive Film

The present invention relates to an anisotropic conductive film.

Anisotropic conductive films in which conductive particles are dispersed in an insulating resin binder are widely used for mounting electronic components such as IC chips on wiring boards and the like. In anisotropic conductive films, it is strongly required to improve the trapping properties of conductive particles in the bumps and to avoid short circuits between adjacent bumps by narrowing the pitch of bumps accompanying high-density mounting of electronic components.

In response to such a demand, it has been proposed to arrange the conductive particles in the anisotropic conductive film into a lattice-like arrangement, and to incline the axis of the arrangement with respect to the longitudinal direction of the anisotropic conductive film (Patent Document 1, Patent Reference 2).

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

[The 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 shape, the bump layout 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, the number density of the conductive particles increases, and the manufacturing cost of the anisotropic conductive film increases.

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

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

The present inventors have found that the conductive particles in the plan view of the anisotropic conductive film are not arranged in a simple lattice, but the conductive particles are repeatedly arranged in the vertical and horizontal directions by the repetition of polygonal units composed of a plurality of conductive particles. The present invention can be conceived by solving the above-mentioned problems by making the sides forming the polygons obliquely intersect with the long-side direction or the short-side direction of the anisotropic conductive film.

That is, the present invention provides 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 connecting the centers of a plurality of conductive particles in sequence, The polygon of the repeating unit has an oblique side to the long-side direction or short-side direction of the anisotropic conductive film. [Effect of invention]

According to the anisotropic conductive film of the present invention, since the conductive particles are not arranged in a simple lattice-like arrangement, but a repeating unit formed of a plurality of conductive particles is repeatedly arranged, so that the distance between the conductive particles is shortened Part of the film is uniformly present in the whole film. In addition, since the polygonal shape of the repeating unit has a side obliquely intersecting with the long-side direction or short-side direction of the anisotropic conductive film, the ability to capture conductive particles in the bump is high. It is thus possible to connect bumps with narrow pitches without causing short circuits.

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 also uniformly present in the entire film, the number density of the conductive particles in the entire anisotropic conductive film can be suppressed The increase in the number density of the conductive particles suppresses the increase in the manufacturing cost. Furthermore, by suppressing an increase in the number density of the conductive particles, it is also possible to suppress an increase in the thrust required for pressing the jig during anisotropic conductive connection. Therefore, the pressure exerted by the self-pressing jig on the electronic parts during the anisotropic conductive connection can be reduced, and the deformation of the electronic parts can be prevented.

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.

<Overall structure of anisotropic conductive film> 1A is a plan view showing an 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. The anisotropic conductive film 1A has a structure in which the conductive particles 2 are arranged in a single layer on the surface of the insulating resin adhesive 3 or its vicinity, and the 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。 <Electroconductive particle> As the conductive particle 2, a user of a well-known anisotropic conductive film can be suitably selected and used. Examples include: metal particles such as nickel, copper, silver, gold, and palladium;

Metal-coated resin particles formed on the surface of resin particles such as polybenzoguanamine. The size of the arranged conductive particles is preferably 1 μm or more and 30 μm or less, more preferably 1 μm or more and 10 μm or less, and still more preferably 2 μm or more and 6 μm or less.

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 viewed from above, and the particle size can be measured and determined. In this case, it is preferable to measure 200 or more pieces, more preferably to measure 500 pieces or more, and still more preferably to measure 1000 pieces or more.

The surfaces of the conductive particles 2 are preferably covered by insulating coating or insulating particle treatment. Such a coating is easily peeled off from the surface of the conductive particle 2 and does not hinder anisotropic conductive connection. In addition, protrusions may be provided on the entire surface or a part of the conductive particles 2 . The height of the protrusions is within 20% of the conductive particle size, preferably within 10%.

<Arrangement of Conductive Particles> In the following FIGS. 1A to 7 , as an example, an arrangement example of the repeating unit when the repeating unit 5 of the polygonal shape is a trapezoid will be described. The arrangement of the conductive particles 2 in the plan view of the anisotropic conductive film 1A shown in FIG. 1A is as follows: a polygonal repeating unit 5 formed by sequentially connecting the centers of a plurality of conductive particles 2a, 2b, 2c, and 2d along the positive The alternate two directions (X direction, Y direction) are repeated and arranged on one surface (ie, the entire surface) of the anisotropic conductive film 1 . Furthermore, the anisotropic conductive film of this invention may have the area|region where electroconductive particle is not arrange|positioned as needed.

The arrangement of the conductive particles 2 can also be regarded as disposing the conductive particles at a part of the apex of the equilateral triangle when the equilateral triangle is arranged without gaps (or the apex of the regular hexagon when the hexagon is arranged without gaps). In other words, it is considered to be an arrangement in which the conductive particles at a specific lattice point are regularly removed from the arrangement in which the conductive particles exist 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 forms a part of the regular hexagon in which the regular triangle is combined, and exists at the lattice point of the hexagonal lattice. If the sides 2a and 2b of the trapezoid are inverted with the sides 2a and 2b as the center, the sides 2c and 2d and the sides 2g, 2g, 2h overlap.

Furthermore, when considering the situation of the repeating unit of the conductive particle 2, it can also be regarded as a regular hexagonal repeating unit 5x composed of the conductive particles 2p, 2q, 2r, 2s, 2t, and 2u along X as shown in FIG. 1B. The direction overlaps one side and repeats, and repeats along the Y direction when the sides and vertices do not overlap. In the present invention, the repeating unit is preferably regarded as a polygon composed of more than 4 conductive particles, and the number of conductive particles is not overlapped. In the case of the sides of the angular shape, it is the smallest unit of polygon that repeats in the vertical and horizontal directions of the anisotropic conductive film.

Each side of the trapezoid of the repeating unit 5 ( FIG. 1A ) is obliquely crossed with the long-side direction and the short-side direction of the anisotropic conductive film 1A. Thereby, the circumscribed line L1 of the longitudinal direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2b, and the conductive particle 2b is adjacent to the conductive particle 2a in the longitudinal direction of the anisotropic conductive film. Moreover, the outer tangent L2 of the short-side direction of the anisotropic conductive film of the conductive particle 2a penetrates the conductive particle 2d, and the conductive particle 2d is adjacent to the conductive particle 2a in the short-side direction of the anisotropic conductive film. Since the long-side direction of the anisotropic conductive film is generally the short-side direction of the bumps during anisotropic conductive connection, if the polygonal side of the repeating unit 5 is shorter than the long-side direction of the anisotropic conductive film 1A The side direction is oblique, which 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 separated from the terminal at the same time and become unhelpful for conduction. The catchability of the conductive particles 2 can be improved.

Furthermore, in the present invention, the repeating units may not necessarily all be oblique to the long-side direction or the short-side direction of the anisotropic conductive film, and the short-side direction of each bump may become the long-side direction of the anisotropic conductive film In this case, it is preferable that each side of the repeating unit and the long-side direction or the short-side direction of the anisotropic conductive film are obliquely crossed from the viewpoint of the capture property of the conductive particles.

On the other hand, when the arrangement pattern of the bumps is radial (so-called fan-out bumps), it is preferable that the polygon in which the repeating unit is formed has the side in the long-side direction or the short-side direction of the anisotropic conductive film. That is, in order to prevent the bumps to be connected from being displaced 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 sides of the polygon of the repeating unit 5 and the long-side direction or the short-side direction of the anisotropic conductive film are not obliquely crossed, the sides of the polygon of the repeating unit 5 are equal to the length of the radially arranged bumps. The edges in the side direction are oblique. Therefore, during the anisotropic conductive connection, most of the conductive particles attached to the edges of the bumps are not captured by the bumps, and the phenomenon that the captureability of the conductive particles is reduced can be avoided.

On the other hand, the radial arrangement pattern of the bumps is usually formed to be bilaterally symmetrical. Therefore, it is preferable that the polygon in which the repeating unit 5 is formed 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 connection. The sides, especially the polygons forming the repeating unit 5, have the sides in the long-side direction or the short-side direction of the anisotropic conductive film, and are 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 units 5 are 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 a trapezoid having a symmetry axis in the short-side direction of the anisotropic conductive film, so that the bottom and top sides of the anisotropic conductive film are the same as those of the anisotropic conductive film 1Ba. The longitudinal direction of the anisotropic conductive film is parallel, and, as in the anisotropic conductive film 1Bb shown in FIG. 2B, the bottom and top sides of the repeating units of the same trapezoid are parallel to the short side direction of the anisotropic conductive film. .

In the present invention, the arrangement of the conductive particles 2 in the repeating unit 5 or the repeating pitch in the vertical and horizontal directions of the repeating unit 5 can be appropriately changed according to the shape or pitch of the terminal serving as the connection object of the anisotropic conductive connection. Therefore, compared with the case where the conductive particles 2 are arranged in a simple lattice shape, the entire anisotropic conductive film can achieve high capture performance with a small number of conductive particles. For example, in order to increase the number density of the conductive particles in the longitudinal direction of the anisotropic conductive film 1Ba, the anisotropic conductive film 1Ba may be arranged as follows: the anisotropic conductive film 1Ca shown in FIG. 3A , repeat the trapezoidal repeating unit 5 in its shape along the width direction of the anisotropic conductive film, and repeat the trapezoidal repeating unit 5 and repeating unit 5B alternately along the longitudinal 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 longitudinal direction of the film. In this case, it is also possible to set the following configuration: as in 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, the following arrangement may be employed: the anisotropic conductive film 1Cb shown in FIG. 3B Generally, the repeating unit 5 of the trapezoid shape is repeated along the longitudinal 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 in which the repeating unit is reversed along the axis of the short-side direction of the anisotropic conductive film. Moreover, it is also possible to set it as the following arrangement: like the anisotropic conductive film 1Db shown in FIG. 4B , the repeating unit 5 is reversed in both the long-side direction and the short-side direction of the anisotropic conductive film. The repeating unit 5B of the shape repeats alternately.

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

In addition, as in the anisotropic conductive film 1F shown in FIG. 6 , the repeating pitch in the Y direction of the repeating unit 5 may be enlarged for the arrangement of the conductive particles in the anisotropic conductive film 1A shown in FIG. 1A . In the arrangement of the conductive particles 2 shown in FIG. 1A , each of the conductive particles 2 overlaps with any of the vertices of the regular hexagon when the regular hexagon is arranged without gaps, but in the arrangement of the conductive particles shown in FIG. 6 , , it is not necessary for all the conductive particles to be the vertices of the regular hexagon when the regular hexagon is arranged without gaps, which is different from the arrangement of the conductive particles shown in FIG. 1A .

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

Like the anisotropic conductive film 1H shown in FIG. 8 , the repeating unit 5 of the trapezoid shape or the repeating unit 5B formed by reversing it can also be repeated along the short side direction or the long side direction of the anisotropic conductive film, and in the A row of individual conductive particles 2p is arranged between the row in the width direction of the anisotropic conductive film of the repeating unit 5 and the row in the width direction of the anisotropic conductive film of the repeating unit 5B. Thereby, the conductive particles 2 are arranged in an orthorhombic lattice, and the conductive particles 2p alone exist in the center of the unit lattice. When the conductive particles are arranged in a rhombic 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 a rhombic lattice shape as shown in FIGS. 8 and 9 , the conductive particles 2 exist in the long-side direction, the short-side direction, and the direction inclined with respect to 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 short circuits during the anisotropic conductive connection.

In addition, the arrangement may be as follows: like the anisotropic conductive film 1J shown in FIG. 10 , a rectangular lattice-like arrangement of the rhombus-shaped repeating units 5 composed of four conductive particles, and the repeating units 5 The rectangular lattice-like arrangement of the rhombus-shaped repeating units 5B reversed in the long-side direction or the short-side direction of the anisotropic conductive film is repeated so that these lattice points do not overlap. Like the anisotropic conductive film 1K shown in FIG. 11 , the particle arrangement may be the same as that of the anisotropic conductive film 1J of FIG. 10 , and the interval between the arrays of the repeating units 5 and 5B in the short-side direction of the film may be widened.

The repeating unit is not limited to the arrangement in which the conductive particles occupy a part of the vertices of the regular hexagon (ie, the lattice points of the hexagonal lattice) when the conductive particles are arranged without gaps in the regular triangle. It can also be set that the conductive particles occupy a part of the lattice points of the square lattice. For example, similar to the arrangement of the conductive particles shown in FIG. 5A , the repeating unit 5 of the trapezoid and the repeating unit 5B obtained by reversing the trapezoid can be alternately repeated in the long and short directions of the anisotropic conductive film. As shown in FIG. 12, the anisotropic conductive film 1L is disposed on the lattice points of the square lattice.

In addition, the number of vertexes of the polygon forming the repeating unit is not limited to four, and may be five or more, six or more, or seven or more. However, in the design or production steps of manufacturing the anisotropic conductive film, in order to easily identify the shape of the repeating unit, the number of vertices of the repeating unit is preferably an even number.

The shape of the polygon forming the repeating unit may or may not be a regular polygon, but a shape having an axis of symmetry is preferable in terms of easy identification of the shape of the repeating unit. In this case, each conductive particle constituting the repeating unit may not exist in the lattice points of the hexagonal lattice or the square lattice. For example, like the anisotropic conductive film 1M shown in FIG. 13 , the repeating unit 5 may be constituted by conductive particles located at the 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 conducting anisotropic conductive connections, the inclination angle of the longitudinal direction of the bumps or terminals relative to the longitudinal direction of the film of the anisotropic conductive film, the anisotropic conductive film. The resin composition of the insulating resin binder in the oriented 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 figure, for example, the arrangement of the repeating units shown in the figure may be inclined. In this case, the aspect formed by inclining at 90°, that is, the long-side direction and the short-side direction of the exchange membrane is also included. Moreover, what changed the space|interval of a repeating unit or the space|interval of the electroconductive particle in a repeating unit may be sufficient.

<The shortest inter-particle distance of conductive particles> The shortest inter-particle distance of the conductive particles is preferably 0.5 times or more of the average particle diameter of the conductive particles, both between adjacent conductive particles within the repeating unit and between adjacent conductive particles between the repeating units. When the distance is too short, short-circuiting is likely to occur due to mutual contact of conductive particles. The upper limit of the distance between adjacent conductive particles is determined according to the shape of the bumps or the pitch of the bumps. For example, when the bump width is 200 μm and the inter-bump space is 200 μm, when there is at least one conductive particle in either the bump width or the inter-bump space, the shortest particle of the conductive particle The distance between them was set to be less than 400 μm. It is preferable to set it as less than 200 micrometers from the point which makes the capture|acquisition property of electroconductive particle reliable.

<Number Density of Conductive Particles> The number density of conductive particles is in the aspect of suppressing the manufacturing cost of the anisotropic conductive film and avoiding the excessive thrust necessary for the pressing jig used in the anisotropic conductive connection. When the average particle size of the conductive particles is less than 10 μm, it is preferably 50,000 pieces/mm ² or less, more preferably 35,000 pieces/mm ² or less, and still more preferably 30,000 pieces/mm ² or less. On the other hand, if the number density of the conductive particles is too small, there is a possibility of poor conduction due to insufficient capture of the conductive particles in the terminals. Therefore, it is preferably 300 particles/mm ² or more, more preferably 500 particles/mm ² or more, and further It is preferably 800 pieces/mm ² or more.

When the average particle diameter of the conductive particles is 10 μm or more, it is preferably 15 particles/mm ² or more, more preferably 50 particles/mm ² or more, and still more preferably 160 particles/mm ² or more. The reason for this is that when the conductive particle size becomes larger, the area occupied by the conductive particles also increases. For the same reason, it is preferably 1800 pieces/mm ² or less, more preferably 1100 pieces/mm ² or less, and still more preferably 800 pieces/mm ² or less.

Furthermore, the number density of the conductive particles may be partially (for example, 200 μm×200 μm) deviated from the above-mentioned number density.

＜Insulating resin adhesive＞ As the insulating resin adhesive 3, a thermally polymerizable composition, a photopolymerizable composition, a photothermal combined polymerizable composition, etc., which are used as insulating resin adhesives among known anisotropic conductive films, can be appropriately selected and used. Among them, the thermally polymerizable composition includes a thermally polymerizable resin composition containing an acrylate compound and a thermal radical polymerization initiator, and a thermally cationic polymerizable resin containing an epoxy compound and a thermal cationic polymerization initiator. Compositions, thermal anionic polymerizable resin compositions containing epoxy compounds and thermal anionic polymerization initiators, etc. Examples of photopolymerizable compositions include photo-radical polymerization containing acrylate compounds and photo-radical polymerization initiators resin composition, etc. As long as there is no particular problem, a plurality of polymerizable compositions may be used in combination. As an example of combined use, the combined use of a thermal cationically polymerizable composition and a thermally radically polymerizable composition, etc. are mentioned.

Here, as a photopolymerization initiator, a plurality of initiators that react with light having different wavelengths may be contained. Thereby, wavelengths used for photocuring of the resin constituting the insulating resin layer during the production of the anisotropic conductive film and photocuring of the resin for bonding electronic parts to each other during the anisotropic conductive connection can be distinguished.

When the insulating resin adhesive 3 is formed using a photopolymerizable composition, all or all of the photopolymerizable compounds contained in the insulating resin adhesive 3 can be cured by light curing 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 circuits and the improvement of trapping are expected. Moreover, the viscosity of the insulating resin layer in the manufacturing process of anisotropic conductive film can be adjusted by adjusting the conditions of this photohardening.

The blending amount of the photopolymerizable compound in the insulating resin adhesive 3 is preferably 30% by mass or less, more preferably 10% by mass or less, and still more preferably less than 2% by mass. The reason for this is that when there are too many photopolymerizable compounds, the thrust applied by pressing 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, in addition to a thermally polymerizable compound, a photopolymerizable compound may be contained separately in a thermopolymerizable composition, and a photopolymerizable initiator may be contained. It is preferable to contain a photopolymerizable compound and a photopolymerization initiator separately in addition to a thermopolymerizable compound. For example, a thermal cationic polymerization initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermal polymerizable compound, a photoradical initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound . Cured products of these polymerizable compositions may be contained in the insulating adhesive 3 .

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

Moreover, the epoxy compound used as a polymerizable compound forms a three-dimensional network structure, and provides favorable heat resistance and adhesiveness, and it is preferable to use a solid epoxy resin and a liquid epoxy resin together. Here, the so-called solid epoxy resin means an epoxy resin which is solid at normal temperature. In addition, the liquid epoxy resin means the epoxy resin which is liquid at normal temperature. In addition, the normal temperature means the temperature range of 5-35 degreeC prescribed|regulated by JIS Z 8703. In the present invention, two or more epoxy compounds may be used in combination. Moreover, you may use together an oxetane compound other than 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 thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and 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 singly or in combination of two or more and use. Among these, bisphenol A type epoxy resins are 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 type epoxy resin, bisphenol F type epoxy resin, novolak phenol type epoxy resin, and naphthalene type epoxy resin. Resin etc. may be used individually by 1 type from these, or may be used in combination of 2 or more types. In particular, it is preferable to use a bisphenol A type epoxy resin from the viewpoints of the viscosity and flexibility of the film.

Among the thermal polymerization initiators, the thermal radical polymerization initiators include, for example, organic peroxides, azo-based compounds, and the like. In particular, organic peroxides which do not generate nitrogen gas which causes bubbles can be preferably used.

If the usage-amount of the thermal radical polymerization initiator is too small, the curing will be poor, and if it is too large, 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 for epoxy compounds can be used. In particular, aromatic perylene salts exhibiting good latency to temperature can be preferably used.

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

As the thermal anionic polymerization initiator, publicly known ones that are generally used can be used. For example, organic acid dihydrazine, dicyandiamide, amine compounds, polyamide amine compounds, cyanate ester compounds, phenol resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, Brünster 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 these, a microcapsule-type latent hardener having an imidazole modified body as a core and coating the surface thereof with polyurethane is preferably used.

The film-forming resin is preferably contained in the thermally polymerizable 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. The film-forming resins include various resins such as phenoxy resins, polyester resins, polyurethane resins, polyesterurethane resins, acrylic resins, polyimide resins, butyral resins, and these may be used alone or may be used. Use in combination of two or more. Among these, from the viewpoints of film formation state, connection reliability, and the like, a phenoxy resin is preferably used.

In order to adjust the melt viscosity, an insulating filler may be contained in the thermally polymerizable composition. It can be exemplified by silica powder, alumina powder, and the like. The size of the insulating filler is preferably 20 to 1000 nm in particle diameter, and the blending 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.

Further, fillers, softeners, accelerators, antiaging agents, colorants (pigments, dyes), organic solvents, ion catcher agents, etc., different from the above-described insulating fillers may be contained.

Moreover, a stress relaxation agent, a silane coupling agent, an inorganic filler, etc. may also be mix|blended as needed. As a stress relaxation agent, a hydrogenated styrene-butadiene block copolymer, a hydrogenated styrene-isoprene block copolymer, etc. are mentioned. Moreover, as a silane coupling agent, an epoxy type, a methacryloyloxy type, an amino type, a vinyl type, a mercapto/thioether type|system|group, a ureide type|system|group, etc. are mentioned. 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, 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 necessary. In addition, 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 conducting a method of holding conductive particles on the surface of an insulating resin adhesive in a specific arrangement as a method for producing an anisotropic conductive film, and pressing the conductive particles into the insulating resin adhesive, 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. Further, as will be described later, as shown in FIG. 14 or FIG. 15 , concave portions 3 b are formed around the exposed portions of the conductive particles 2 pressed into the insulating resin adhesive 3 , or as shown in FIG. 16 . The minimum melt viscosity is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, and more preferably 3000 to 15000 Pa·s, preferably 3000 to 10000 Pa·s. As an example of this minimum melt viscosity, a rotational rheometer (manufactured by TA Instruments) can be used, the temperature increase rate is 10°C/min, the measurement pressure is kept constant at 5 g, and a measurement plate with a diameter of 8 mm is used. and ask for. Furthermore, when the step of press-fitting the conductive particles 2 into the insulating resin adhesive 3 is performed at preferably 40 to 80° C., more preferably 50 to 60° C., the concave portion 3 b or 3 c is formed in the same manner as described above. On the other hand, the lower limit of the viscosity at 60°C is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, More preferably, it is 15000 Pa·s or less, and still more preferably 10000 Pa·s or less.

By setting the viscosity of the resin constituting the insulating resin adhesive 3 to a high viscosity as described above, when an anisotropic conductive film is used, the conductive particles 2 are sandwiched between the connection objects such as opposing electronic components. In the case of heating and pressing, 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 1 μm or more and 60 μm or less, more preferably 1 μm or more and 30 μm or less, and still more preferably 2 μm or more and 15 μm or less. Moreover, as for the relationship between the thickness La of the insulating resin binder 3 and the average particle diameter D of the electroconductive particle 2, it is preferable that the ratio (La/D) is 0.6-10. When the thickness La of the insulating resin adhesive 3 is too large, the conductive particles tend to be displaced during anisotropic conductive connection, and the ability to capture the conductive particles in the terminal decreases. This tendency is 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 a specific arrangement by the insulating resin adhesive 3 . In particular, when the terminals to be connected are 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 to 2.

(Embedding of conductive particles in insulating resin adhesive) The embedded state of the conductive particles 2 in the insulating resin adhesive 3 is not particularly limited, and anisotropic conductive connection is performed by sandwiching an anisotropic conductive film between opposing parts and applying heat and pressure In this case, as shown in FIG. 14 and FIG. 15 , it is preferable to expose a part of the conductive particles 2 from the insulating resin adhesive 3 to the surface 3 a of the insulating resin adhesive in the central part between the adjacent conductive particles 2 . A recess 3b is formed around the exposed portion of the conductive particle 2, or as shown in FIG. 16, the insulating resin adhesive directly above the conductive particle 2 pressed into the insulating resin adhesive 3 In part, the concave portion 3c is formed with respect to the same tangent plane 3p as described above, and the surface of the insulating resin binder 3 directly above the conductive particle 2 has undulations. For the flattening of the conductive particles 2 that occurs when the conductive particles 2 are held between the electrodes of the opposing electronic components and heated and pressed, the presence of the concave portion 3b as shown in Fig. 14 and Fig. 15 and the absence of the concave portion 3b In contrast, the conductive particles 2 receive less resistance from the insulating resin binder 3 . Therefore, it becomes easy to hold the conductive particle 2 between the opposing electrodes, and the conduction performance is also improved. In addition, in the resin constituting the insulating resin binder 3, by forming the concave portions 3c on the surface of the resin directly above the conductive particles 2 (FIG. 16), the pressure during heating and pressurization changes compared with the case where the concave portions 3c do not exist. It is easy to concentrate on the conductive particles 2, and it becomes easy to hold the conductive particles 2 in the electrode, and the conduction performance is improved.

In terms of easily obtaining the effects of the concave portions 3b and 3c described above, the ratio of the maximum depth Le of the concave portion 3b (FIG. 14 and FIG. 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 20-25%, the maximum diameter Ld of the concave portion 3b (FIG. 14, FIG. 15) around the exposed portion of the conductive particle 2 is equal to 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 concave portion 3c ( FIG. 14 ) of the resin directly above the conductive particles 2 is equal to The ratio (Lf/D) of the average particle diameter D of the conductive particles 2 is preferably greater than 0, and preferably less than 10%, more preferably less than 5%.

In addition, the diameter Lc of the exposed portion of the conductive particles 2 can be set to be equal to or less than the average particle diameter D of the conductive particles 2 , preferably 10 to 90% of the particle diameter D. The conductive particle 2 may be exposed at one point of the top 2t of the conductive particle 2, or the conductive particle 2 may be completely embedded in the insulating resin binder 3, and the diameter Lc may be zero.

(Position of conductive particles in thickness direction of insulating resin adhesive) In terms of easily obtaining the effect of the recesses 3b described above, the distance between the tangent plane 3p and the deepest part of the conductive particles 2 (hereinafter referred to as the amount of embedding) Lb and the ratio of the average particle diameter D of the conductive particles 2 (Lb/D) (Hereinafter referred to as the burying rate) is preferably 60% or more and 105% or less.

<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 in which the conductive particles 2 are arranged.

In the case where the above-mentioned concave portion 3b is formed in the insulating resin adhesive 3, the insulating adhesive layer 4 may be laminated on the insulating resin adhesive 3 where the concave portion 3b is formed, as in the anisotropic conductive film 1d shown in FIG. 17 . On the surface, like the anisotropic conductive film 1e shown in FIG. 18, it may be laminated on the surface opposite to the surface on which the recessed 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 electronic components are anisotropically conductively connected using the anisotropic conductive film, the spaces formed by the electrodes or bumps of the electronic components can be filled to improve the adhesiveness.

In addition, 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 surface where the recesses 3b and 3c are formed. On the side of the first electronic component (in other words, the insulating resin adhesive 3 is on the side of the second electronic component such as the substrate). Thereby, the inadvertent movement of the conductive particles can be avoided, and the catchability can be improved. In addition, generally, the first electronic component such as an IC chip is placed on the pressing jig side, the second electronic component such as a substrate is placed on the stage side, and the anisotropic conductive film and the second electronic component are temporarily pressure-bonded, and then the first electronic component is placed on the stage. The electronic component and the second electronic component are formally crimped, but the anisotropic conductive film is temporarily attached to the first electronic component according to the size of the thermocompression bonding area of the second electronic component, and then the first electronic component and the second electronic component are temporarily bonded. Electronic parts are officially crimped.

As the insulating adhesive layer 4, one used as an insulating adhesive layer among known anisotropic conductive films can be appropriately selected and used. The insulating adhesive layer 4 may be the one that uses the same resin as the insulating resin adhesive 3 described above and further adjusts the viscosity to be lower. The greater the difference in the minimum melt viscosity between 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 components with the insulating adhesive layer 4, and it can be expected to improve the mutual relationship between the electronic components. The effect of continuity. In addition, the more this difference exists, the smaller the amount of movement of the resin constituting the insulating resin adhesive 3 during the anisotropic conductive connection is relatively small, and the easier it is to improve the trapping properties of the conductive particles of the terminal. Practically speaking, the minimum melt viscosity of the insulating adhesive layer 4 and the insulating resin adhesive 3 is preferably 2 or more, more preferably 5 or more, and still more preferably 8 or more. On the other hand, if the ratio is too large, when the long anisotropic conductive film is made into a package, there is a risk of resin overflow or blocking, 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 still more preferably 100 to 2000 Pa·s.

As a method of forming the insulating adhesive layer 4, a coating composition containing the same resin as the resin forming the insulating resin adhesive 3 can be formed into a film by a coating method, dried, or further cured, or a It forms into a film by a well-known method.

The thickness of the insulating adhesive layer 4 is preferably 1 μm or more and 30 μm or less, and more preferably 2 μm or more and 15 μm or less.

In addition, the minimum melt viscosity of the entire 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, and practically It can be set to 8000 Pa·s or less, and in order to easily fill between bumps, it can be 200 to 7000 Pa·s, preferably 200 to 4000 Pa·s.

Further, insulating fillers such as silica fine particles, alumina, and aluminum hydroxide may be added to the insulating resin adhesive 3 or the insulating adhesive layer 4 as needed. The blending amount of the insulating filler is preferably 3 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the resin constituting the layers. Thereby, even if the anisotropic conductive film is melted at the time of anisotropic conductive connection, it is possible to suppress unnecessary movement of the conductive particles due to the melted resin.

<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 an insulating resin adhesive formed on the release film is formed. The conductive particles 2 are pressed into the insulating resin adhesive 3 by covering the conductive particles 2 on the insulating resin adhesive 3 , so that the conductive particles 2 are transferred to the insulating resin adhesive 3 . Alternatively, the insulating adhesive layer 4 may be further laminated on the conductive particles 2 . In this way, the anisotropic conductive film 1A can be obtained.

In addition, after the concave part of the transfer mold is filled with conductive particles, the insulating resin adhesive is coated thereon, so that 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. The particles are pressed into the insulating resin binder, whereby an anisotropic conductive film can also be produced. The embedded amount (Lb) of the conductive particles can be adjusted by the pressing force and temperature during the pressing. In addition, the shape and depth of the concave portions 3b and 3c can be adjusted by the viscosity of the insulating resin adhesive during the press-fitting, the press-fitting speed, and the temperature. For example, the lower limit of the viscosity of the insulating resin binder when the conductive particles are pressed is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and still more preferably 4500 Pa·s or more, and the upper limit is set to It is preferably 20,000 Pa·s or less, more preferably 15,000 Pa·s or less, and still more preferably 10,000 Pa·s or less. Moreover, such a viscosity can be obtained preferably at 40-80 degreeC, More preferably at 50-60 degreeC. More specifically, in the case of manufacturing the anisotropic conductive film 1a having the concave portion 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 in. It is 8000 Pa·s (50-60°C), and in the case of manufacturing the anisotropic conductive film 1c having the concave portion 3c shown in FIG. 16, the viscosity of the insulating resin adhesive when the conductive particles are pressed is preferably set. It is 4500 Pa·s (50～60℃).

Furthermore, as the transfer mold, in addition to filling the concave portion with conductive particles, a micro-adhesive is applied to the top surface of the convex portion and the conductive particle is attached to the top surface.

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

In addition, as a method of arranging the 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 body＞ In order to continuously supply the anisotropic conductive film to the connection of electronic parts, it is preferable to form a film roll body wound on a reel. The length of the film roll body may be 5 m or more, preferably 10 m or more. There is no upper limit in particular, but from the viewpoint of the operability of unloading the cargo, it is preferably 5,000 m or less, more preferably 1,000 m or less, and still more preferably 500 m or less.

The film package may be formed by connecting an anisotropic conductive film shorter than the entire length with a connection tape. The connection site may exist in a plurality of places, and may exist regularly or randomly. The thickness of the connection tape is not particularly limited as long as it does not hinder the performance, but if it is too thick, it will affect the overflow or adhesion of the resin, so it is preferably 10 to 40 μm. In addition, the width of the film is not particularly limited, but is 0.5 to 5 mm as an example.

According to the film roll, 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 to anisotropy the first electronic parts such as FPCs, IC chips, and IC modules, and the second electronic parts such as FPCs, rigid substrates, ceramic substrates, glass substrates, and plastic substrates by heat or light. It can be preferably used in the case of conductive connection. Moreover, IC chips or IC modules may be stacked to perform anisotropic conductive connection between the first electronic components. The thus obtained connecting structure and its manufacturing method 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, for example, an interface of the anisotropic conductive film on the side where conductive particles in the film thickness direction of the anisotropic conductive film are present, in terms of improving connection reliability. A second electronic component such as a wiring board is mounted with a first electronic component such as an IC chip on the temporarily attached anisotropic conductive film, and thermocompression bonding is performed from the side of the first electronic component. Moreover, you may connect by photohardening. Furthermore, in this connection, it is preferable to align the long-side direction of the terminal of an electronic component and the short-side direction of an anisotropic conductive film from the viewpoint of the connection work efficiency. Example

Experimental Example 1 to Experimental Example 8 (Fabrication of anisotropic conductive film) Regarding the anisotropic conductive film for COG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of the conductive particles on the film forming performance and conduction characteristics was investigated as follows.

First, the resin compositions for forming the insulating resin adhesive and the 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 by the preparation conditions of the insulating resin composition. The resin composition for 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 to form the resin composition shown in Table 2 on the PET film. An insulating resin adhesive layer with a thickness of La. In the same manner, the 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 prepared so that the arrangement of the conductive particles in plan view was the arrangement shown in Table 2, and the distance between the centers of the nearest conductive particles in the repeating units was 6 μm. The pellets of a known transparent resin were poured into the mold in a molten state, and 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 arrangement (number density of 32,000 particles/mm ² ), and one of the lattice axes was inclined by 15° with respect to the longitudinal direction of the anisotropic conductive film. °.

Metal-coated resin particles (Sekisui Chemical Industry Co., Ltd., AUL703, average particle size 3 μm) were prepared as conductive particles, the conductive particles were filled in the concave portion of the resin mold, and the insulating resin adhesive was coated thereon. By pressing at 60° C. and 0.5 MPa, they were bonded together. 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 to 70°C, 0.5 Mpa) to press them into the insulating resin adhesive. , and a film in which the conductive particles were embedded in the insulating resin adhesive in the state shown in Table 2 was produced. In this case, the embedded 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 pressed, and in the other experimental examples, a film in which conductive particles were embedded could be produced. In the observation with a metal microscope, as shown in Table 2, a concave portion was observed around the exposed portion of the embedded conductive particle or directly above the embedded conductive particle. Furthermore, in each of the experimental examples other than Experimental Example 4, both the concave portion around the exposed portion of the conductive particle and the concave portion directly above the conductive particle were observed, and Table 4 shows the most clearly observed by each experimental example. The measured value of the concave part.

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

(Evaluation) For the anisotropic conductive films 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 property evaluation on the pressing tool side, and each evaluation was obtained by heating and pressing (180° C., 5 seconds) with the pressing tool. Use a linker. In this case, the thrust obtained by the pressing tool was changed into three stages of low (40 MPa), medium (60 MPa), and high (80 MPa), and three types of connectors for evaluation were obtained.

Here, regarding the IC for conducting characteristic evaluation and the glass substrate, the terminal patterns of these correspond to each other, and the dimensions are as follows. Moreover, when connecting the IC for evaluation and a glass substrate, the long-side direction of an anisotropic conductive film and the short-side direction of a bump were aligned.

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

Glass substrate (ITO wiring) Glass material: 1737F made by Corning Shape: 30×50mm Thickness: 0.5 mm Electrode: ITO wiring

The initial on-resistance of the obtained connector for evaluation was measured and evaluated according to the following three-stage evaluation criteria. Evaluation criteria for initial on-resistance (practically, as long as it is less than 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: 0.8 Ω or more

(b) Turn-on reliability Carry out a reliability test in which the connector for evaluation prepared in (a) is placed in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 hours, and the on-resistance after measuring in the same manner as the initial on-resistance, according to the following three The evaluation criteria of the stage are evaluated.

Evaluation criteria for on-reliability (practically, as long as it is less than 5 Ω, there is no problem) A: Less than 1.2 Ω B: 1.2 Ω or more and less than 2 Ω C: 2 Ω 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 The 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 nearest 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℃（Pa·s） Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Buried state of conductive particles Buried 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 The presence or absence of recesses Have Have Have - Have Have Have Have The maximum depth Le of the concave part (the ratio to the particle size D of the conductive particles) <50% <50% <50% - <50% <50% <50% <50% Maximum diameter Ld of concave portion (Ratio to 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 turn-on reliability A A A - A A A B Thrust: Medium 60 MPa Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: High 80 MPa Initial on-resistance A A A - A A A A turn-on 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 a concave portion 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 was 1500 Pa·s or more, it was found that by adjusting the conditions at the time of embedding the conductive particles, it was possible to form near the conductive particles of the insulating resin adhesive. convex portion, and the thus obtained anisotropic conductive film has good conduction characteristics when used for COG. In addition, compared with the experimental example 8 of the hexagonal lattice arrangement, in the experimental examples 1 to 7 in which the number density of the conductive particles is low, it can be seen that the anisotropic conductive connection can be performed at a lower pressure.

(c) Short circuit occurrence rate Using the anisotropic conductive films of experimental examples 1 to 3 and 5 to 8, using the following IC for evaluation of short-circuit occurrence rate, under the connection conditions of 180 ° C, 60 MPa, and 5 seconds to obtain evaluation connectors, and measure the obtained The number of short circuits in the evaluation connector was determined 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-teeth TEG (test element group, test element group) in 7.5 μm space): Outline: 15×13 mm 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 preferable, and all the anisotropic conductive films of Experimental Examples 1 to 3 and 5 to 8 are less than 50 ppm.

Furthermore, in each of the experimental examples other than 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 Examples 9 to 16 (Fabrication of anisotropic conductive film) Regarding the anisotropic conductive film for FOG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of the conductive particles on the film forming performance and conduction characteristics was investigated as follows.

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

In the production step of the anisotropic conductive film, after the conductive particles were pressed into the insulating resin adhesive, the film shape was not maintained in Experimental Example 12, and the film shape was maintained in other experimental examples. Therefore, with respect to the anisotropic conductive films of the experimental examples other than the experimental example 12, the embedded state of the conductive particles was observed and measured with a metal microscope, and the following evaluations were further performed. Table 4 shows the embedded state of the conductive particles in each experimental example. The embedded state shown in Table 4 is the same as that in Table 2, and is the measured value in which the concave portion of the insulating resin adhesive was most clearly observed for each experimental example.

(Evaluation) For the anisotropic conductive films 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 experimental example was cut to 2 mm × 40 mm, sandwiched between the FPC for evaluation of conduction characteristics and the glass substrate, and heated and pressurized with a tool width of 2 mm (180°C, 5 seconds) , and obtained the linker for each evaluation. In this case, the thrust obtained by the pressing tool was changed into three stages of low (3 MPa), medium (4.5 MPa), and high (6 MPa), and three types of connectors for evaluation were obtained. The on-resistance of the obtained connector for evaluation was measured in the same manner as in Experimental Example 1, and the measured value was evaluated in three stages according to the following criteria.

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: 2.0 Ω or more

(b) Turn-on reliability The connector for evaluation prepared in (a) was placed in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 hours, and the subsequent on-resistance was measured in the same manner as the initial on-resistance, and the following criteria were used to evaluate the on-resistance in three stages. Measurements.

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

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 a concave portion. On the other hand, in the experimental example in which the minimum melt viscosity of the insulating resin layer was 1500 Pa·s or more, it was found that recesses could be formed in the vicinity of the conductive particles of the insulating resin binder by adjusting the conditions for burying the conductive particles. , and the thus obtained anisotropic conductive film has good conduction characteristics when used for FOG.

(c) Short circuit occurrence rate The number of short circuits in the evaluation connector for which the initial on-resistance was measured was measured, and the short-circuit occurrence rate was calculated from the number of short circuits obtained by the measurement and the number of gaps in the evaluation connector. As long as the short-circuit occurrence rate is less than 100 ppm, there is no practical problem. The short-circuit occurrence rates of Experimental Examples 9 to 11 and 13 to 16 were all less than 100 ppm.

Furthermore, in each of the experimental examples other than the 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 & Sumitomo Metal Chemical Co., Ltd.) 20 40 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Industry Co., Ltd.) 20 20 20 20 2-functional urethane acrylate oligomer (UN-9200A, Genshang Industrial Co., Ltd.) 25 35 35 35 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 1 1 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 1 1 1 Benzoyl peroxide (Nyper BW, Nippon Oil Co., Ltd.) 5 5 5 5 insulating adhesive layer Phenoxy resin (FX-316ATM55, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.) 50 2-functional acrylate (A-DCP, Shin-Nakamura Chemical Industry Co., Ltd.) 20 2-functional urethane acrylate oligomer (UN-9200A, Genshang Industrial Co., Ltd.) 30 Silane coupling agent (A-187, Momentive Performance Materials Co., Ltd.) 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku Co., Ltd.) 1 Benzoyl peroxide (Nyper BW, Nippon Oil Co., Ltd.) 5

[Table 4] FOG evaluation Experimental example 9 Experimental Example 10 Experimental Example 11 Experimental example 12 Experimental Example 13 Experimental Example 14 Experimental example 15 Experimental Example 16 The 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 nearest 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℃（Pa·s） Insulating resin adhesive layer 12000 3000 2000 1100 12000 12000 12000 12000 Buried state of conductive particles Buried 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 The presence or absence of recesses Have Have Have - Have Have Have Have The maximum depth Le of the concave part (the ratio to the particle size D of the conductive particles) <50% <50% <50% - <50% <50% <50% <50% The maximum diameter Ld of the concave part (the ratio to the particle diameter D of the conductive particle) <1.3 <1.3 <1.3 - <1.3 <1.3 <1.3 <1.3 Evaluation Thrust: 3 MPa lower Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: Medium 4.5 MPa Initial on-resistance A A A - A A A B turn-on reliability A A A - A A A B Thrust: High 6 MPa Initial on-resistance A A A - A A A A turn-on 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: repeating unit

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

Claims (10)

An anisotropic conductive film comprising conductive particles arranged in an insulating resin adhesive, and Polygonal repeating units are repeatedly arranged in a plan view, and the polygonal repeating units are formed by connecting the centers of a plurality of conductive particles in sequence, The polygon of the repeating unit has an oblique side to the long-side direction or short-side direction of the anisotropic conductive film. The anisotropic conductive film according to claim 1, wherein the repeating unit is arranged on one surface 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 any one of claims 1 to 3, wherein each side of the polygon forming the repeating unit is oblique to the long-side direction or the short-side direction of the anisotropic conductive film. The anisotropic conductive film according to any one of claims 1 to 3, wherein the polygon forming the repeating unit has a side in a long-side direction or a short-side direction of the anisotropic conductive film. The anisotropic conductive film according to any one of claims 1 to 5, wherein, in the case of inverting a polygon constituting a repeating unit with one side of the polygon as a center, the number of repeating units after the inversion is as large as One side of the angle overlaps one side of the adjacent repeating unit before the inversion. The anisotropic conductive film according to any one of claims 1 to 6, wherein the conductive particle unit forms a part of a regular polygon. The anisotropic conductive film according to any one of claims 1 to 5, wherein the arrangement of the conductive particles constituting the conductive particle unit overlaps with the vertices of the hexagons when the regular hexagons are arranged without gaps. A connection structure in which a first electronic component and a second electronic component are anisotropically conductively connected by the anisotropic conductive film of any one of claims 1 to 8. A method of manufacturing a connection structure, which manufactures a connection structure of a first electronic component and a second electronic component by thermocompression bonding of a first electronic component and a second electronic component through an anisotropic conductive film, and the use request The anisotropic conductive film of any one of Items 1 to 8 serves as an anisotropic conductive film.

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