TWI743116B - Anisotropic conductive film - Google Patents

Abstract

Provided is an anisotropic conductive film that can cope with narrow pitch bumps and can reduce the number density of conductive particles compared to conventional anisotropic conductive films. In the anisotropic conductive film 1A, conductive particles 2 are arranged on the insulating resin adhesive 3, and a polygonal repeating unit 5 is repeatedly arranged along the vertical and horizontal directions in a plan view. The polygonal repeating unit 5 is a plurality of conductive particles. The centers of the particles 2 are formed by connecting sequentially. The side of the polygon of the repeating unit 5 obliquely intersects the long-side direction or the short-side direction of the anisotropic conductive film.

Description

Anisotropic conductive film

The present invention relates to an anisotropic conductive film.

An anisotropic conductive film formed by dispersing conductive particles in an insulating resin adhesive is widely used when mounting electronic components such as IC chips on wiring boards. In the anisotropic conductive film, it is strongly required to improve the catchability 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 parts.

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

Patent Document 1: Japanese Patent No. 4887700

Patent Document 2: Japanese Patent Application Publication No. 9-320345

As described in Patent Documents 1 and 2, when the conductive particles are arranged in a simple lattice shape In this case, the layout of the bumps should be dealt with 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 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. There are also designs for insulating resin adhesives. Constraints.

Therefore, the subject of the present invention is to be able to cope with bumps with a narrow pitch and to reduce the number density of conductive particles compared with the conventional anisotropic conductive film.

The inventors found that instead of setting the conductive particles in the top view of the anisotropic conductive film as a simple lattice-like arrangement, the conductive particles are repeatedly arranged in the vertical and horizontal directions by repeating the polygonal unit composed of a plurality of conductive particles. Particles, and the sides forming the polygon are obliquely intersected with respect to the long-side direction or the short-side direction of the anisotropic conductive film, so as to solve the above-mentioned problems, thereby contemplating the present invention.

That is, the present invention provides an anisotropic conductive film in which conductive particles are arranged in an insulating resin adhesive, and a polygonal repeating unit is repeatedly arranged in a plan view. The polygonal repeating unit is composed of a plurality of conductive particles. The centers are sequentially connected and formed, and the polygons of the repeating units have sides that obliquely intersect the long side direction or the short side direction of the anisotropic conductive film.

According to the anisotropic conductive film of the present invention, since the conductive particles are not set as simple The lattice-like arrangement is set to repeatedly arrange the repeating unit formed by a plurality of conductive particles, so that the reduced distance between the conductive particles is uniformly present in the entire film. In addition, since the polygonal shape of the repeating unit has a side obliquely intersecting the long-side direction or the short-side direction of the anisotropic conductive film, the conductive particles in the bumps have high trapping properties. Therefore, it is possible to connect the 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 part where the distance between particles of conductive particles is enlarged is also uniformly present in the entire film, the number density of conductive particles in the entire anisotropic conductive film can be suppressed Increase, 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 pushing force necessary to press the jig during anisotropic conductive connection. Therefore, it is possible to reduce the pressure exerted by the self-pressing jig on the electronic component during the anisotropic conductive connection, and to prevent the deformation of the electronic component.

1A, 1Ba, 1Bb, 1Ca, 1Cb, 1Da, 1Db, 1Ea, 1Eb, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M, 1a, 1b, 1c, 1d, 1e‧‧‧Anisotropic conductivity membrane

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 is a plan view explaining the arrangement of conductive particles in an anisotropic conductive film 1A of the embodiment.

FIG. 1B is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1A of the embodiment.

FIG. 1C is a cross-sectional view of the anisotropic conductive film 1A of the embodiment.

FIG. 2A is a plan view explaining the arrangement of conductive particles of the anisotropic conductive film 1Ba of the embodiment.

FIG. 2B is a plan view illustrating the arrangement of conductive particles in the anisotropic conductive film 1Bb of the embodiment.

FIG. 3A is a plan view explaining the arrangement of conductive particles of the anisotropic conductive film 1Ca of the embodiment.

FIG. 3B is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1Cb of the embodiment.

4A is a plan view illustrating the arrangement of conductive particles of the anisotropic conductive film 1Da of the embodiment.

4B is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1Db of the embodiment.

FIG. 5A is a plan view illustrating the arrangement of conductive particles in the anisotropic conductive film 1Ea of the embodiment.

FIG. 5B is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1Eb of the embodiment.

FIG. 6 is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1F of the embodiment.

FIG. 7 is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1G of the embodiment.

FIG. 8 is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1H of the embodiment.

FIG. 9 is a plan view explaining the arrangement of conductive particles of the anisotropic conductive film 1I of the embodiment.

FIG. 10 is a plan view illustrating the arrangement of conductive particles in the anisotropic conductive film 1J of the embodiment.

FIG. 11 is a plan view explaining the arrangement of conductive particles of the anisotropic conductive film 1K of the embodiment.

FIG. 12 is a plan view explaining the arrangement of conductive particles in the anisotropic conductive film 1L of the embodiment.

FIG. 13 is a plan view explaining the arrangement of conductive particles of the anisotropic conductive film 1M of the embodiment.

FIG. 14 is a cross-sectional view of the anisotropic conductive film 1a of the embodiment.

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 the anisotropic conductive film 1e of the embodiment.

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 symbol indicates the same or equivalent constituent element.

<Integral structure of anisotropic conductive film>

FIG. 1A is a plan view showing the arrangement of conductive particles of 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 conductive particles 2 are arranged in a single layer on the surface of an insulating resin adhesive 3 or in the vicinity thereof, 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.

<Conductive particles>

(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1μm以上且30μm以下，更佳為1μm以上且10μm以下，進而較佳為2μm以上且6μm以下。 As the conductive particles 2, a user in a well-known anisotropic conductive film can be appropriately selected and used. For example, metal particles such as nickel, copper, silver, gold, palladium, etc.; polyamide and polyphenylguanidine coated with metals such as nickel

(polybenzoguanamine) and other resin particles formed on the surface of metal-coated resin particles, etc. The size of the conductive particles to be arranged 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 with an image-type or laser-type particle size distribution meter. It is also possible to observe the anisotropic conductive film from a plan view and measure the particle size to obtain it. In this case, it is preferable to measure 200 or more, more preferably 500 or more, and even more preferably 1000 or more.

The surface of the conductive particles 2 is preferably coated by insulating coating, insulating particle treatment, or the like. Such a coating easily peels 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 part of the conductive particles 2. The height of the protrusion is within 20% of the conductive particle size, preferably within 10%.

<Configuration of conductive particles>

In the following FIGS. 1A to 7, 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 in the top view of the anisotropic conductive film 1A shown in FIG. The alternate 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 optionally have a region where no conductive particles are arranged.

The arrangement of the conductive particles 2 can also be regarded as 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 that it is an arrangement in which the conductive particles at specific lattice points are regularly removed from the arrangement of the conductive particles existing in 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, which exists in the lattice points of the hexagonal lattice. If one side 2a, 2b of the trapezoid is inverted, the side 2c, 2d and the adjacent repeating unit of the trapezoid (ie, the repeating unit composed of conductive particles 2e, 2f, 2g, 2h) side 2g, 2h overlap.

Furthermore, when considering the repeating unit of the conductive particle 2, as shown in FIG. The direction overlaps one side and repeats, and repeats along the Y direction when the sides and vertices are not overlapped. In the present invention, the repeating unit is preferably regarded as a polygon composed of 4 or more conductive particles, and is not overlapped. In the case of the side of the angle, the polygon 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) obliquely intersects 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, and the conductive particle 2b is adjacent to the conductive particle 2a in the longitudinal direction of the anisotropic conductive film. In addition, the outer tangent line 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. Generally, in anisotropic conductive connection, the long side direction of the anisotropic conductive film becomes the short side direction of the bump. Therefore, if the polygonal side of the repeating unit 5 and the anisotropic conductive film 1A The oblique intersection of the long side direction or the short side direction can prevent a plurality of conductive particles from being arranged in a straight line along the edge of the bump, thereby avoiding a plurality of conductive particles arranged in a straight line from leaving the terminal and becoming helpless Due to the phenomenon of conduction, the capture performance of the conductive particles 2 can be improved.

Furthermore, in the present invention, the repeating unit may not necessarily have all sides obliquely intersecting 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, in terms of the capturing properties of conductive particles, it is preferable that each side of the repeating unit obliquely intersect the long-side direction or the short-side direction of the anisotropic conductive film.

On the other hand, when the arrangement pattern of the 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 the 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 Application Publication No. 2007-19550, Japanese Patent Application Publication No. 2015-232660, etc. ), in this case, the angle formed by the long side direction of each bump and the long side direction and the short side direction of the anisotropic conductive film gradually changes. Therefore, even if the polygonal side of the repeating unit 5 is not obliquely crossed 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 aligned with the length of each bump in a radial arrangement. The edges of the side direction are oblique. Therefore, it is possible to avoid the phenomenon that most of the conductive particles attached to the edge of the bump during anisotropic conductive connection are not captured by the bump, resulting in a decrease in the capturing property of the conductive particles.

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

In the present invention, the arrangement of the conductive particles 2 in the repeating unit 5 or the repeating pitch of the repeating unit 5 in the vertical and horizontal directions can be appropriately changed according to the shape or pitch of the terminal 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 anisotropic conductive film as a whole can achieve higher trapping performance with a smaller number of conductive particles. For example, for the anisotropic conductive film 1Ba, in order to increase the number density of conductive particles in the longitudinal direction of the anisotropic conductive film, it can also be configured as follows: like the anisotropic conductive film 1Ca shown in FIG. 3A , Repeating the trapezoidal repeating unit 5 in its shape along the width direction of the anisotropic conductive film, and repeating the trapezoidal repeating unit 5 and the repeating unit 5B alternately along the longitudinal direction of the anisotropic conductive film, the repeating unit 5B is a shape formed by reversing the repeating unit of the trapezoid along the axis of the long side of the film. In this case, it can also be configured as follows: like the anisotropic conductive film 1Da as shown in FIG. The repeating unit of the shape of 5B.

Similarly, for the 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: anisotropic conductive film 1Cb as shown in FIG. 3B Generally, the repeating unit 5 of the trapezoid is repeated in its shape along the long side direction of the anisotropic conductive film, and the repeating unit 5 and the repeating unit 5 are repeated along the width direction of the anisotropic conductive film. The element 5B is alternately repeated, and the repeating unit 5B is a shape formed by reversing the repeating unit along the axis of the short side direction of the anisotropic conductive film. In addition, it can also be configured as follows: Like the anisotropic conductive film 1Db shown in FIG. 4B, the repeating unit 5 is formed by inverting the repeating unit 5 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 anisotropic conductive film 1Ca, in order to reduce the number density in 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. In order to reduce the number density of 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 is the interval between the repeated rows in the width direction of the anisotropic conductive film.

In addition, like the anisotropic conductive film 1F shown in FIG. 6, for the arrangement of conductive particles of the anisotropic conductive film 1A shown in FIG. 1A, the repeating pitch of the repeating unit 5 in the Y direction may be enlarged. 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 hexagon when the regular hexagons are arranged without gaps, but in the configuration of the conductive particles shown in FIG. 6 , It is not necessary that all the conductive particles become the vertices of the regular hexagons when the regular hexagons are arranged without gaps. This is different from the configuration of the conductive particles shown in FIG. 1A.

Moreover, 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 the repeating units 5 adjacent in the Y direction, or other repeats can be arranged. unit. In addition, the X-direction repeating pitch of the repeating unit 5 can also be appropriately changed, and individual conductive particles or other repeating units can also be arranged between the X-direction repeating pitches.

Like the anisotropic conductive film 1H shown in FIG. 8, repeating the trapezoidal repeating unit 5 along the short side direction or the long side direction of the anisotropic conductive film or the repeating unit formed by reversing it 5B, and 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. As a result, the conductive particles 2 are arranged in a rhombic lattice, and the individual conductive particles 2p exist in the center of the unit lattice. When the conductive particles are arranged in a rhombic lattice manner, in order to reduce the number density of conductive particles, the repeating unit 5 itself may be formed into a rhombus like the anisotropic conductive film 1I shown in FIG. 9. By arranging the conductive particles 2 into 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 these directions of the anisotropic conductive film , Therefore, it becomes easy to balance the improvement of the capture property of the conductive particles and the suppression of the short circuit during the anisotropic conductive connection.

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

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

In addition, the number of vertices of the polygon forming the repeating unit is not limited to 4, but can be 5 or more, it may be 6 or more, or it may be 7 or more. However, in the design or production steps of the anisotropic conductive film manufacturing, 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. In terms of easy recognition of the shape of the repeating unit, a shape having an axis of symmetry is preferred. In this case, the conductive particles 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 composed of conductive particles located at the apex of a regular octagon. The polygonal shape of the repeating unit can be based on 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 the terminal relative to the film long side direction of the anisotropic conductive film, and the difference The resin composition of the insulating resin adhesive 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 unit shown in the figure, and for example, it may be formed by tilting the arrangement of the repeating unit shown in the figure. In this case, it also includes the aspect in which it is inclined by 90°, that is, the aspect in which the long-side direction and the short-side direction of the membrane are exchanged. In addition, it may be obtained by changing the interval of the repeating unit or the interval of the conductive particles in the repeating unit.

<The shortest distance between conductive particles>

The shortest inter-particle distance of the conductive particles between adjacent conductive particles in the repeating unit and between adjacent conductive particles between the repeating units is preferably 0.5 times or more of the average particle diameter of the conductive particles. If the distance is too short, it becomes easy to cause a short circuit due to the 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 200μm and the space between bumps is 200μm, the conductive particles are placed in the bump width or between the bumps. When there is at least one in any one of the spaces, the shortest inter-particle distance of the conductive particles is set to be less than 400 μm. In terms of ensuring the capturing properties of conductive particles, it is preferably less than 200 μm.

<Number density of conductive particles>

The number density of conductive particles in terms of suppressing the manufacturing cost of the anisotropic conductive film and avoiding excessive thrust required by the pressing jig used in the anisotropic conductive connection, the average particle size of the conductive particles is not up to In the case of 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 conductive particles is too small, there is a risk of poor conduction due to insufficient capture of conductive particles by the terminal. Therefore, it is preferably 300 particles/mm ² or more, more preferably 500 ^{particles/mm 2} or more, and further Preferably it is 800 pieces/mm ² or more.

Moreover, 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 is that if the conductive particle size becomes larger, the area ratio of 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 conductive particles may locally (for example, 200 μm×200 μm) deviate from the above number density.

<Insulating resin adhesive>

As the insulating resin adhesive 3, a thermally polymerizable composition, a photopolymerizable composition, a photo-thermal polymerizable composition, etc. used as an insulating resin adhesive in a well-known anisotropic conductive film can be appropriately selected and used. Among them, the thermally polymerizable composition includes a thermally radically polymerizable resin composition containing an acrylate compound and a thermal radical polymerization initiator, and a thermally radically polymerizable resin composition containing an epoxy compound and thermal A thermally cationically polymerizable resin composition of a cationic polymerization initiator, a thermally anionic polymerizable resin composition containing an epoxy compound and a thermal anionic polymerization initiator, etc. As the photopolymerizable composition, an acrylate compound and a light Photo-radical polymerizable resin composition of radical polymerization initiator, etc. As long as there is no particular problem, multiple polymerizable compositions may be used in combination. Examples of the combined use include the combined use of a thermally cationically polymerizable composition and a thermally radically polymerizable composition.

Here, as the photopolymerization initiator, multiple initiators that react to light of different wavelengths may be contained. Thereby, it is possible to distinguish the wavelength used in the light curing of the resin constituting the insulating resin layer during the manufacture of the anisotropic conductive film and the light curing of the resin used to bond the electronic parts to each other during the anisotropic conductive connection.

In the case of using a photopolymerizable composition to form the insulating resin adhesive 3, light curing at the time of manufacturing the anisotropic conductive film can make all or all of the photopolymerizable compound contained in the insulating resin adhesive 3 Part of the light hardens. By this light curing, 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. In addition, by adjusting the light curing conditions, the viscosity of the insulating resin layer in the manufacturing step of the anisotropic conductive film can be adjusted.

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 is that if there are too many photopolymerizable compounds, the pushing force applied by pressing during anisotropic conductive connection will increase.

On the other hand, the thermopolymerizable composition contains a thermopolymerizable compound and a thermopolymerization initiator, and as the thermopolymerizable compound, one that also functions as a photopolymerizable compound can be used. In addition to the thermally polymerizable compound, the thermally polymerizable composition may also contain a photopolymerizable compound. It also contains a photopolymerizable initiator. It is preferable to contain a photopolymerizable compound and a photopolymerization initiator in addition to the thermally polymerizable 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 photo radical initiator is used as a photopolymerization initiator, and an acrylate compound is used as a photopolymerizable compound. . The insulating adhesive 3 may contain hardened products of these polymerizable compositions.

As the acrylate compound used as a thermally or photopolymerizable compound, a conventionally known thermally polymerizable (meth)acrylate monomer can be used. For example, a monofunctional (meth)acrylate-based monomer and a multifunctional (meth)acrylate-based monomer with more than difunctionality can be used.

In addition, when the epoxy compound used as the polymerizable compound forms a three-dimensional network structure and provides good heat resistance and adhesiveness, it is preferable to use a solid epoxy resin and a liquid epoxy resin in combination. Here, the so-called solid epoxy resin means an epoxy resin that is solid at room temperature. In addition, the term "liquid epoxy resin" means an epoxy resin that is liquid at room temperature. In addition, the term "normal temperature" refers to the temperature range of 5 to 35°C specified in JIS Z 8703. In the present invention, two or more epoxy compounds can be used in combination. In addition to epoxy compounds, oxetane compounds may also be used in combination.

The solid epoxy resin is not particularly limited as long as it is compatible with liquid epoxy resins and is solid at room temperature. Examples include bisphenol A epoxy resins, bisphenol F epoxy resins, and multifunctional epoxy resins. Resin, dicyclopentadiene type epoxy resin, novolak phenol type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, etc., can be used alone or in combination of two or more And use. Among them, bisphenol A type epoxy resin is preferably used.

Liquid epoxy resins are not particularly limited as long as they are liquid at room temperature, and examples include bisphenol A epoxy resins, bisphenol F epoxy resins, novolac phenol epoxy resins, and naphthalene epoxy resins. Resin etc. may be used individually by 1 type from these, or may be used in combination of 2 or more types. In particular, from the viewpoints of the viscosity and flexibility of the film, it is preferable to use a bisphenol A epoxy resin.

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

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

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

Too little use of the thermal cationic polymerization initiator tends to cause poor hardening. Too much also tends to reduce product life. Therefore, relative to 100 parts by mass of the epoxy compound, it is preferably 2-60 parts by mass, more preferably 5-40 parts by mass.

As the thermal anionic polymerization initiator, a known one that is generally used can be used. Examples include: organic acid dihydrazine, dicyandiamine, amine compounds, polyamide compounds, cyanate ester compounds, phenol resins, acid anhydrides, carboxylic acids, tertiary amine compounds, imidazoles, Lewis acids, and Burenst An acid salt, a polythiol curing agent, a urea resin, a melamine resin, an isocyanate compound, a blocked isocyanate compound, etc. may be used alone or in combination of two or more. Among these, it is preferable to use a microcapsule-type latent hardening agent in which an imidazole modified body is used as the core and the surface is coated with polyurethane.

It is preferable to include a film-forming resin 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. From the viewpoint of film-forming properties, It is preferably an average molecular weight of about 10,000 to 80,000. Examples of the film-forming resin include various resins such as phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, acrylic resin, polyimide resin, and butyraldehyde resin. These resins may be used alone or may be used alone. Use in combination of two or more types. Among these, it is preferable to suitably use a phenoxy resin from the viewpoints of the film formation state, connection reliability, and the like.

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 or alumina powder. The size of the insulating filler is preferably a particle size of 20 to 1000 nm, 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.

Furthermore, it may contain fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion catcher agents, etc. different from the above-mentioned insulating fillers.

In addition, a stress reliever, a silane coupling agent, an inorganic filler, etc. can also be blended as necessary. As a stress reliever, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer, etc. are mentioned. In addition, 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 and drying, or further curing, or by forming a film in advance by a known method. 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 peeling film such as a polyethylene terephthalate film that has been peeled off.

(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, etc. For example, as a method of manufacturing an anisotropic conductive film, when conducting a method of holding conductive particles on the surface of an insulating resin adhesive with a specific arrangement, and pressing the conductive particles into the insulating resin adhesive, In terms of forming 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. In addition, as described below, as shown in FIG. 14 or FIG. 15, a concave portion 3b is formed around the exposed portion of the conductive particles 2 pressed into the insulating resin adhesive 3, or as shown in FIG. In terms of forming the recess 3c directly above the conductive particles 2 pressed into the insulating resin adhesive 3, the minimum melt viscosity is preferably 1500 Pa‧s or more, more preferably 2000 Pa‧s or more, and more preferably 3000~ 15000Pa‧s, especially 3000~10000Pa‧s. Regarding the minimum melt viscosity, as an example, a rotary rheometer (manufactured by TA Instrument Co., Ltd.) can be used, and it can be determined by using a measuring plate with a diameter of 8mm, which is constant under the conditions of a temperature increase rate of 10°C/min and a measurement pressure of 5g. out. In addition, when the step of pressing the conductive particles 2 into the insulating resin adhesive 3 is performed at 40 to 80°C, more preferably 50 to 60°C, the recesses 3b or 3c are formed in the same manner as described above. In terms of the viscosity at 60°C, the lower limit is preferably 3000 Pa‧s or more, more preferably 4000 Pa‧s or more, more preferably 4500 Pa‧s or more, and the upper limit is preferably 20000 Pa‧s or less, more preferably 15000Pa ‧S or less, more preferably 10000Pa‧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 facing objects to be connected such as electronic parts. 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 adhesive 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. In addition, in terms of the relationship between the thickness La of the insulating resin adhesive 3 and the average particle diameter D of the conductive particles 2, the ratio (La/D) is preferably 0.6-10. If the thickness La of the insulating resin adhesive 3 is too large, the conductive particles become easily dislocated during the anisotropic conductive connection, and the ability to capture the conductive particles in the terminal decreases. If La/D exceeds 10, this tendency is significant. 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. Especially when the connected terminal 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.

(The embedding state of conductive particles in insulating resin adhesive)

Regarding the embedding state of the conductive particles 2 in the insulating resin adhesive 3, there is no particular limitation. An anisotropic conductive connection is made 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. 14 and 15, relative to the surface 3a of the insulating resin adhesive at the center between adjacent conductive particles 2 The cut plane 3p is formed around the exposed part of the conductive particle 2 to form a recess 3b, or as shown in FIG. 16, the insulating resin adhesive directly above the conductive particle 2 pressed into the insulating resin adhesive In part, the concave portion 3c is formed with respect to the same tangential plane 3p as described above, so that the surface of the insulating resin adhesive 3 directly above the conductive particles 2 has undulations. For the flattening of the conductive particles 2 generated when the conductive particles 2 are sandwiched between the electrodes of the opposing electronic components and heated and pressurized, the presence of the concave portion 3b as shown in FIG. 14 and FIG. 15 and the absence of the concave portion Compared with the case of 3b, the resistance of the conductive particles 2 from the insulating resin adhesive 3 is reduced. Therefore, it becomes easy to pinch the conductive particles 2 between the opposing electrodes, and the conduction performance is also improved. In addition, in the resin constituting the insulating resin adhesive 3, by forming recesses 3c on the surface of the resin directly above the conductive particles 2 (FIG. 16), the pressure at the time of heating and pressurizing changes compared with the case where the recesses 3c are not present. It becomes easier to concentrate on the conductive particles 2, and it becomes easier to pinch the conductive particles 2 in the electrode, and the conduction performance is improved.

In terms of easily obtaining the effects of the above-mentioned recesses 3b, 3c, the ratio of the maximum depth Le of the recess 3b around the exposed portion of the conductive particle 2 (FIGS. 14 and 15) to the average particle diameter D of the conductive particle 2 (Le /D) is preferably less than 50%, more preferably less than 30%, and still 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 and The ratio of the average particle diameter D of the conductive particles 2 (Ld/D) is preferably 100% or more, more preferably 100 to 150%. The maximum depth Lf of the resin recess 3c (FIG. 14) directly above the conductive particles 2 and 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%.

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

(Position of conductive particles in the thickness direction of insulating resin adhesive)

In terms of easily obtaining the effect of the above-mentioned concave portion 3b, the distance between the tangent plane 3p and the deepest part of the conductive particle 2 (hereinafter referred to as the amount of embedment) Lb to the average particle diameter D of the conductive particle 2 (Lb/D) (Hereinafter referred to as the embedding 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 the resin constituting the insulating resin adhesive 3 may be laminated on the insulating resin adhesive 3 on which the conductive particles 2 are arranged.

In the case where the above-mentioned recess 3b is formed in the insulating resin adhesive 3, an insulating adhesive layer 4 can be laminated on the insulating resin adhesive 3 where the recess 3b is formed like the anisotropic conductive film 1d shown in FIG. The surface may be laminated on the surface opposite to the surface on which the recessed portion 3b is formed like the anisotropic conductive film 1e shown in FIG. 18. The same is true when the insulating resin adhesive 3 is formed with the recessed portion 3c. By laminating the insulating adhesive layer 4, when an anisotropic conductive film is used for anisotropic conductive connection of electronic components, the space formed by the electrodes or bumps of the electronic component can be filled to improve adhesion.

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, 3c are formed. 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). In this way, the inadvertent movement of the conductive particles can be avoided, and the capturing performance can be improved. In addition, usually the first electronic component such as 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 the anisotropic conductive film is temporarily crimped with the second electronic component, and then the first The electronic component and the second electronic component are formally crimped, but according to the size of the thermal compression bonding area of the second electronic component, the anisotropic conductive film is temporarily pasted on the first electronic component, and then the first electronic component and the second The electronic parts are officially crimped.

As the insulating adhesive layer 4, a known anisotropic conductive film can be appropriately selected and used as an insulating adhesive layer. The insulating adhesive layer 4 can also be used with the above-mentioned insulating tree Grease adhesive 3 has the same resin and further adjusts the viscosity to a lower one. The more 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 can be expected to improve the relationship between the electronic parts The effect of subsequent sex. In addition, the greater the difference, the smaller the amount of movement of the resin constituting the insulating resin adhesive 3 during the anisotropic conductive connection is relatively smaller, and therefore the easier it is for the terminal to capture conductive particles to improve. 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-sized anisotropic conductive film is made into a roll, there is a risk of resin overflow or blocking, so it is practically preferable to 15 the following. More specifically, the preferable 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 particularly 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 by a coating method and dried, or further cured, or preliminarily The film is formed by a well-known method.

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

In addition, the lowest 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 thickness of the insulating resin adhesive 3 to the insulating adhesive layer 4, which is practical It can be set below 8000Pa‧s, in order to easily fill between the bumps, it can be 200~7000Pa‧s, preferably 200~4000Pa‧s.

Furthermore, if necessary, 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. Insulating filler The blending amount 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 melts during anisotropic conductive connection, it is possible to prevent the molten resin from causing the conductive particles to move unnecessarily.

<Manufacturing method of anisotropic conductive film>

As a manufacturing method of anisotropic conductive film, for example, manufacturing a transfer mold for arranging conductive particles in a specific arrangement, filling the recesses of the transfer mold with conductive particles, and forming an insulating resin adhesive on the release film 3 is coated on it and pressure is applied, and the conductive particles 2 are pressed into the insulating resin adhesive 3, thereby transferring the conductive particles 2 to the insulating resin adhesive 3. Or, an insulating adhesive layer 4 is further laminated on the conductive particles 2. In this way, an anisotropic conductive film 1A can be obtained.

In addition, after filling the concave portion of the transfer mold with conductive particles, the insulating resin adhesive is coated on it, 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 adhesive, thereby making it possible to produce an anisotropic conductive film. The embedding amount (Lb) of conductive particles can be adjusted by the pressing force, temperature, etc. during the pressing. In addition, the shape and depth of the recesses 3b and 3c can be adjusted by the viscosity of the insulating resin adhesive during press-fitting, press-fitting speed, temperature, and the like. For example, the lower limit of the viscosity of the insulating resin adhesive when the conductive particles are pressed into 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 preferably set to 20000Pa‧s or less, more preferably 15000Pa‧s or less, and still more preferably 10000Pa‧s or less. Moreover, such a viscosity can be obtained at preferably 40 to 80°C, more preferably 50 to 60°C. More specifically, when manufacturing the anisotropic conductive film 1a with 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. 8000Pa‧s(50~60℃), used in manufacturing tools In the case of the anisotropic conductive film 1c of the recess 3c shown in FIG. 16, it is preferable to set the viscosity of the insulating resin adhesive when the conductive particles are pressed into 4500 Pa·s (50-60°C).

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

These transfer molds can be manufactured using or applying well-known techniques such as mechanical processing, photolithography, and printing.

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

<Roll body>

In order for the anisotropic conductive film to be continuously provided for the connection of electronic parts, it is preferably made into 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 particular upper limit, but in terms of the handling of the delivery, it is preferably 5000 m or less, more preferably 1000 m or less, and still more preferably 500 m or less.

The film roll body may be formed by connecting anisotropic conductive films shorter than the full length by a connecting tape. There may be multiple connection sites, and they may exist regularly or randomly. The thickness of the connecting tape is not particularly limited as long as it does not hinder the performance. However, if it is too thick, it will affect the overflow or adhesion of the resin, so it is preferably 10-40μm. In addition, the width of the film is not particularly limited, but as an example, it is 0.5 to 5 mm.

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

<Connected structure>

The anisotropic conductive film of the present invention is used to heat or light FPC, IC chip, IC module, etc. Electronic parts can be preferably used for anisotropic conductive connection with second electronic parts such as FPC, rigid substrate, ceramic substrate, glass substrate, and plastic substrate. In addition, IC chips or IC modules may be stacked to connect first electronic components to each other in anisotropic conductive manner. The resulting connection structure and its manufacturing method are also part of the present invention.

As a method of connecting electronic parts using an anisotropic conductive film, in terms of improving connection reliability, for example, it is preferable to temporarily stick the interface on the side where conductive particles are present in the thickness direction of the anisotropic conductive film. The second electronic component such as the wiring board is mounted with the first electronic component such as an IC chip to the temporarily attached anisotropic conductive film, and the thermal compression bonding is performed from the side of the first electronic component. In addition, it is also possible to use light curing for connection. Furthermore, in this connection, in terms of connection efficiency, 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.

Example

Experimental example 1~Experimental example 8

(Production of Anisotropic Conductive Film)

Regarding the anisotropic conductive film used for COG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of conductive particles on the film formation performance and conduction characteristics was studied in the following manner.

First, the resin compositions for forming the insulating resin adhesive and the insulating adhesive layer were prepared with the compositions shown in Table 1. 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 forming the insulating resin adhesive was coated on a PET film with a film thickness of 50μm by a bar coater, dried in an oven at 80°C for 5 minutes, and the PET film was formed as shown in Table 2 Insulating resin adhesive layer of thickness La. In the same way, the insulating adhesive layer was formed on the PET film with the thickness shown in Table 2.

Then, the layout of the conductive particles in a plan view became the layout shown in Table 2, and the distance between the centers of the repeating units closest to the conductive particles became 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 with the recesses arranged as shown in Table 2. Here, in Experimental Example 8, the conductive particles are arranged in a hexagonal lattice arrangement (number density 32000/mm ² ), and one of the lattice axes is inclined with respect to the longitudinal direction of the anisotropic conductive film by 15 °.

As conductive particles, metal-coated resin particles (Sekisui Chemical Industry Co., Ltd., AUL703, average particle size 3μm) were prepared, and the conductive particles were filled into the recesses of the resin mold, and the insulating resin adhesive was coated on it. Press at 60°C and 0.5 MPa to bond it together. Then, the insulating resin adhesive is peeled from the mold, and the conductive particles on the insulating resin adhesive are pressurized (pressing conditions: 60~70℃, 0.5Mpa), thereby pressing them into the insulation. In the fringe resin adhesive, 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. In other experimental examples, a film embedded with conductive particles could be produced. In the observation with a metal microscope, as shown in Table 2, recesses were observed around the exposed part of the embedded conductive particles or directly above the embedded conductive particles. Furthermore, in each experimental example except Experimental Example 4, both the recesses around the exposed part of the conductive particles and the recesses directly above the conductive particles were observed. The most clearly observed are shown in Table 4 for each experimental example. The measured value of the concave part.

An anisotropic conductive film with a two-layer resin layer is produced by laminating an insulating adhesive layer on the side of the conductive particle-embedded film that is pressed into the conductive particles. However, in Experimental Example 4, the film shape was not maintained after the conductive particles were press-fitted, so the following evaluation was not performed.

(Evaluation)

For the anisotropic conductive film of each experimental example, (a) initial on-resistance and (b) on-state 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 evaluating the conduction characteristics of the pressing tool, and each evaluation was obtained by heating and pressing the pressing tool (180°C, 5 seconds) Use a linker. In this case, the thrust obtained by the pressing tool is changed into three stages of low (40MPa), medium (60MPa), and high (80MPa), and three types of evaluation connectors are obtained.

Here, regarding the IC for conduction characteristic evaluation and the glass substrate, these terminal patterns correspond to each other, 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 conduction characteristic evaluation

Shape: 1.8×20.0mm

Thickness: 0.5mm

Bump specifications: size 30×85μm, distance between bumps 50μm, bump height 15μm

Glass substrate (ITO wiring)

Glass material: 1737F manufactured by Corning

Shape: 30×50mm

Thickness: 0.5mm

Electrode: ITO wiring

The initial on-resistance of the evaluation connector obtained by measurement is evaluated according to the following three-stage evaluation criteria.

Evaluation criteria for initial on-resistance (practically, as long as it does not reach 2Ω, there is no problem)

A: Less than 0.4Ω

B: 0.4Ω or more and less than 0.8Ω

C: 0.8Ω or more

(b) Conduction reliability

Carry out the reliability test of placing the connection object for evaluation made in (a) in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 hours, and measure the on-resistance afterwards in the same way as the initial on-resistance, according to the following 3 Evaluation based on the evaluation criteria of the stage.

Evaluation criteria for continuity reliability (practically, as long as it does not reach 5Ω, there is no problem)

A: Less than 1.2Ω

B: 1.2Ω or more and less than 2Ω

C: 2Ω or more

According to Table 2, it can be seen that in Experimental Example 4 where the lowest melt viscosity of the insulating resin layer is 800 Pa·s, it is difficult to form a film with recesses in the insulating resin adhesive near the conductive particles. On the other hand, it can be seen that in the experimental example where the minimum melt viscosity of the insulating resin adhesive is 1500 Pa•s or more, the convexity can be formed near the conductive particles of the insulating resin adhesive by adjusting the conditions when the conductive particles are embedded. In addition, the anisotropic conductive film thus obtained has good conduction characteristics when used in COG. In addition, it can be seen that compared with Experimental Example 8 with a hexagonal lattice arrangement, in Experimental Examples 1-7 with a lower number density of conductive particles, anisotropic conductive connection can be performed at a lower pressure.

(c) Short circuit incidence rate

Using the anisotropic conductive films of Experimental Examples 1~3 and 5~8, using the following IC for evaluating the incidence of short-circuits, the evaluation connector was obtained under the connection conditions of 180℃, 60MPa, and 5 seconds, and the evaluation was obtained by measurement. Using the number of short-circuits of the connected object, the ratio of the number of short-circuits measured to the number of terminals of the evaluation IC is used to obtain the occurrence rate of short-circuits.

IC for short circuit rate evaluation (comb TEG (test element group) in 7.5μm space):

Shape: 15×13mm

Thickness: 0.5mm

Bump specifications: size 25×140μm, distance between bumps 7.5μm, bump height 15μm

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

Furthermore, for each experimental example except Experimental Example 4, the conductive particles captured by each bump were measured, and as a result, more than 10 conductive particles were captured.

Experimental example 9~16

(Production of Anisotropic Conductive Film)

Regarding the anisotropic conductive film used for FOG connection, the influence of the resin composition of the insulating resin adhesive and the arrangement of conductive particles on the film formation performance and conduction characteristics was studied in the following manner.

That is, the resin composition forming the insulating resin adhesive and the insulating adhesive layer was prepared with the composition shown in Table 3, and using these, the anisotropic conductive film was produced in the same manner as in Experimental Example 1. Table 4 shows the distance between the arrangement of the conductive particles and the center of the conductive particles in this case. In Experimental Example 16, the conductive particles were arranged in a hexagonal lattice arrangement (number density 15000/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 manufacturing 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, but the film shape was maintained in the other experimental examples. Therefore, for the anisotropic conductive film 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 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 that in Table 2, and is the measured value when the concave portion of the insulating resin adhesive is most clearly observed for each experimental example.

(Evaluation)

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

Evaluation FPC:

Terminal pitch: 20μm

Terminal width/space between terminals: 8.5μm/11.5μm

Polyimide film thickness (PI)/copper foil thickness (Cu)=38/8, tin plating (Sn plating)

Alkali-free glass substrate:

Electrode: ITO wiring

Thickness: 0.7mm

Evaluation criteria for initial on-resistance

A: Less than 1.6Ω

B: 1.6Ω or more and less than 2.0Ω

C: 2.0Ω or more

(b) Conduction reliability

Place the connection object for evaluation made in (a) in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 hours, and measure the on-resistance afterwards in the same way as the initial on-resistance, and evaluate the on-resistance in 3 stages according to the following criteria Measurements.

Evaluation criteria for continuity reliability

A: Less than 3.0Ω

B: 3.0Ω or more and less than 4Ω

C: 4.0Ω or more

According to Table 4, it can be seen that in Experimental Example 12 where the minimum melt viscosity of the insulating resin layer is 800 Pa·s, it is difficult to form a film with recesses. On the other hand, it can be seen that in the experimental example where the minimum melt viscosity of the insulating resin layer is 1500 Pa·s or more, by adjusting the conditions when the conductive particles are embedded, the recesses can be formed near the conductive particles of the insulating resin adhesive. In addition, the anisotropic conductive film thus obtained has good conduction characteristics when used in FOG.

(c) Short circuit incidence rate

Measure the number of short-circuits of the connection object for evaluation of the measured initial on-resistance, according to the measurement The number of short-circuits obtained and the number of gaps in the evaluation connector were used to determine the incidence of short-circuits. As long as the short-circuit occurrence rate is less than 100 ppm, there is no practical problem.

The short-circuit incidence rates of 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, more than 10 conductive particles were captured.

Claims (11)

An anisotropic conductive film, in which conductive particles are arranged in an insulating resin adhesive, and a polygonal repeating unit is repeatedly arranged in a plan view. The polygonal repeating unit connects the centers of a plurality of conductive particles in sequence. Formed, the polygon of the repeating unit has sides oblique to the long or short direction of the anisotropic conductive film, and the repeating unit does not overlap on the polygonal side of the repeating unit, and it runs along the anisotropic conductive film in a plan view. The vertical and horizontal directions are repeated. For example, the anisotropic conductive film in the first item of the scope of patent application, wherein the repeating unit is arranged on one side of the anisotropic conductive film. For example, the anisotropic conductive film of item 1 or 2 in the scope of patent application, wherein the repeating unit is a trapezoid. For example, the anisotropic conductive film of item 1 or 2 of the scope of patent application, wherein each side of the polygon forming the repeating unit obliquely intersects the long side direction or the short side direction of the anisotropic conductive film. For example, the anisotropic conductive film of item 1 or 2 of the scope of patent application, wherein the polygons forming the repeating unit have sides in the long-side direction or the short-side direction of the anisotropic conductive film. For example, the anisotropic conductive film of item 1 or 2 of the scope of patent application, wherein the arrangement of the conductive particles constituting the conductive particle unit overlaps the vertices of the hexagons when the regular hexagons are arranged without gaps. For example, the anisotropic conductive film of item 1 or 2 of the scope of patent application, wherein the conductive particles are metal particles or metal-coated resin particles. For example, the anisotropic conductive film of item 1 or 2 in the scope of patent application, wherein the surface of the conductive particles is covered. For example, the anisotropic conductive film of item 1 or 2 in the scope of patent application has a resin adhesive layer laminated. A connecting structure that connects a first electronic component and a second electronic component with an anisotropic conductive film through the anisotropic conductive film in any one of items 1 to 9 in the scope of the patent application. A method for manufacturing a connecting structure, which manufactures a connecting structure of a first electronic component and a second electronic component by thermally compressing a first electronic component and a second electronic component through an anisotropic conductive film, and applying for The anisotropic conductive film in any one of items 1 to 9 of the scope of the patent is used as an anisotropic conductive film.

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