HK1260569B - Method for manufacturing anisotropic conductive film, and anisotropic conductive film - Google Patents

Description

Method for manufacturing anisotropic conductive film and anisotropic conductive film

Technical Field

The present technology relates to a method for manufacturing an anisotropic conductive film containing conductive particles, and an anisotropic conductive film. The present application claims priority on the basis of Japanese patent application No. 2016-.

Background

Conventionally, an Anisotropic Conductive Film (ACF) for mounting electronic components such as IC chips is known. In recent years, it has been studied to separate or arrange conductive particles in an anisotropic conductive film from adjacent conductive particles independently using a mold having a plurality of openings (see, for example, patent document 1).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2014-060151.

Disclosure of Invention

Problems to be solved by the invention

However, conductive particles used for a mold having a plurality of openings are graded so that the particle size distribution is steep (sharp) so as not to hinder anisotropic connection, and thus manufacturing cost is high.

Further, in the anisotropic conductive film in which conductive particles having significantly different particle diameters are arranged under the surface field of view, insufficient penetration of the conductive particles occurs at the time of pressing, which causes conduction failure.

The present technology was conceived to solve the aforementioned problems, and provides a method for manufacturing an anisotropic conductive film that can reduce manufacturing costs. Further, an anisotropic conductive film capable of suppressing occurrence of conduction failure is provided. Further, a method for producing a filler-disposed film and a filler-disposed film are provided, which can reduce the production cost.

Means for solving the problems

As a result of diligent studies, the present inventors have found that the production cost can be reduced by screening conductive particles or a filler using a member having a plurality of openings. Further, it was found that occurrence of conduction failure can be suppressed by forming a predetermined pattern in a particle size distribution chart of conductive particles arranged in an anisotropic conductive film under a surface field of view.

That is, the method for manufacturing an anisotropic conductive film according to the present technology includes: a holding step of supplying conductive particles having a plurality of particle diameters to a member having a plurality of openings and holding the conductive particles in the openings; and a transfer step of transferring the conductive particles held in the opening portion to the adhesive film, wherein in a particle size distribution chart (X-axis: particle size [ mu ] m; Y-axis: number of particles) of the conductive particles held in the opening portion, a range of a particle size having a slope equal to or larger than a maximum peak value is substantially infinite in a chart shape.

Further, an anisotropic conductive film according to the present technology includes: an insulating adhesive formed in a film shape; and a plurality of conductive particles arranged on the insulating adhesive under a surface field of view, wherein in a particle size distribution chart (X axis: particle size [ mu ] m; Y axis: number of particles) of the conductive particles, a range of particle sizes with an inclination more than or equal to a maximum peak value is in a chart shape with an infinite size.

In the film roll package according to the present technology, the anisotropic conductive film is wound around a roll core.

That is, the method for producing a filler-disposed film according to the present technology includes: a holding step of supplying a filler having a plurality of particle diameters to a member having a plurality of openings, and holding the filler in the openings; and a transfer step of transferring the filler held in the opening portion to the adhesive film, wherein in a particle size distribution chart (X-axis: particle size [ mu ] m; Y-axis: number of particles) of the filler held in the opening portion, a range of a particle size having a slope of at least a maximum peak is substantially infinite in a chart shape.

Further, a filler arrangement film according to the present technology includes: an insulating adhesive formed in a film shape; and a plurality of fillers arranged in the insulating adhesive under a surface field of view, wherein in a particle size distribution chart (X axis: particle size [ mu ] m; Y axis: number of particles) of the fillers, a range of particle sizes having a slope of not less than a maximum peak is substantially infinite in a chart shape.

Effects of the invention

According to this technique, the conductive particles or the filler are screened using a member having a plurality of openings, and the manufacturing cost can be reduced. In addition, in the particle size distribution chart of the conductive particles arranged in the anisotropic conductive film under the surface field of view, the occurrence of conduction failure can be suppressed by forming the particle size distribution chart into a predetermined chart shape.

Drawings

Fig. 1 is a cross-sectional view schematically showing a state where conductive particles are supplied to a member having a plurality of openings.

Fig. 2 (a) is a graph schematically showing the particle size distribution of the conductive particles supplied to the opening, and fig. 2 (B) is a graph schematically showing the particle size distribution of the conductive particles held in the opening.

FIG. 3 is a graph schematically showing another example of the particle size distribution of the conductive particles held in the openings.

Fig. 4 is a graph schematically showing another example of the particle size distribution of the conductive particles held in the openings.

Fig. 5 is a graph schematically showing another example of the particle size distribution of the conductive particles held in the openings.

Fig. 6 (a) is a graph schematically showing the particle size distribution of the conductive particles on the lower limit side of the particle size supplied to the opening, and fig. 6 (B) is a graph schematically showing the particle size distribution of the conductive particles held in the opening.

FIG. 7 is a graph schematically showing another example of the particle size distribution of the conductive particles held in the openings.

Fig. 8 is a cross-sectional view schematically showing a state where adhesive films are opposed to each other in a transfer step.

Fig. 9 is a sectional view schematically showing the method of manufacturing a connected body according to the present embodiment, fig. 9 a shows a placement step (S1), and fig. 9B shows a curing step (S2).

Detailed Description

Hereinafter, embodiments of the present technology will be described in detail in the following order.

1. Method for manufacturing anisotropic conductive film

2. Anisotropic conductive film

3. Method for manufacturing connection structure and connection structure

4. Method for producing filler-coated film and filler-coated film

5. Examples of the embodiments

< 1. method for producing anisotropic conductive film

The method for manufacturing an anisotropic conductive film according to the present embodiment includes: a holding step (A) of supplying conductive particles having a plurality of particle diameters to a member having a plurality of openings and holding the conductive particles in the openings; and a transfer step (B) of transferring the conductive particles held in the openings to the adhesive film. The holding step (a) and the transfer step (B) will be described below.

[ holding step (A) ]

(opening member)

Fig. 1 is a cross-sectional view schematically showing a state in which conductive particles are supplied onto a member having a plurality of openings. As shown in fig. 1, the member 10 is a mold having an opening portion with an opening dimension S of a predetermined opening diameter or opening width. Examples of the mold include a metal material such as stainless steel, a transparent inorganic material such as glass, and an organic material such as poly (meth) acrylate or a crystalline resin. The opening forming method can be formed by various known techniques. For example, the substrate may be provided by machining, may be provided by photolithography, may be provided by printing, and is not particularly limited. The mold may have various shapes such as a plate shape and a roll shape, and is not particularly limited.

The opening portion contains conductive particles therein, and examples of the shape of the opening include a polygonal column such as a cylindrical column or a quadrangular prism, a pyramid such as a conical cone or a quadrangular pyramid, and the like. The position on the member of the opening, that is, the position of the conductive particles arranged in the anisotropic conductive film in a plan view, preferably has a specific shape and regularity, and is preferably arranged in a regular pattern such as a lattice pattern or a staggered pattern (a pattern of thousand ). Examples of the lattice shape include an orthorhombic lattice, a hexagonal lattice, a square lattice, a rectangular lattice, and a parallel lattice. Further, the film may have regularity in a predetermined arrangement shape with respect to the longitudinal direction of the film.

The opening size S can be set based on the particle diameter of the conductive particles disposed in the anisotropic conductive film. For example, the ratio of the diameter of the opening to the particle diameter of the conductive particles (i.e., the diameter of the opening/the particle diameter of the conductive particles) is preferably 1.1 to 2.0, and more preferably 1.3 to 1.8, from the viewpoint of the balance between easy storage of the conductive particles and easy insertion of the insulating resin. For example, the ratio of the particle size of the conductive particles to the depth of the openings (i.e., the particle size of the conductive particles/the depth of the openings) is preferably 0.4 to 3.0, and more preferably 0.5 to 1.5, from the viewpoint of improving the balance between the transferability and the retention property of the conductive particles. Further, the diameter and depth of the opening can be determined by a laser microscope. The average particle diameter of the conductive particles used in the production process can be measured by a particle size distribution meter of an image type or a laser type. Further, it is preferable to use an image-type particle size distribution meter because an accurate particle size (particle diameter) can be obtained. An example of the image-type particle size distribution measuring apparatus is FPIA-3000 (MALVERN).

The opening dimension S is preferably equal to or greater than 60% of the total opening, more preferably equal to or greater than 80% of the total opening, and still more preferably equal to or greater than all of the openings. By making the size of the opening different, any one of the plurality of conductive particle diameters is easily held, and by making the size of the opening the same, the particle diameter of the obtained anisotropic conductive film is easily made uniform. In any case, the conductive particles significantly larger than the openings are not substantially retained in the openings. Thus, in the particle size distribution chart (X-axis: particle size [ μm ]; Y-axis: number of particles) of the conductive particles held in the opening, the range in which the slope is equal to or larger than the particle size of the maximum peak can be obtained in a substantially infinite graph shape.

In the case where there are conductive particles that are significantly smaller than the opening, there is a concern that a plurality of conductive particles will remain in the opening, but the unnecessary conductive particles will be scraped off by the method of containing conductive particles described below. If the conductive particles are not removed, the fine conductive particles are present in one opening or in the vicinity of the opening, but are not helpful or less influential on the connection, and therefore may be ignored. This is because the resin flows during connection and hardly overlaps in the connection direction of the bumps. In addition, in the case where relatively small conductive particles having a size contributing to connection are present, it is expected that the conduction performance can be improved. When the conductive particles are sandwiched between the terminals, the conductive particles can be expected to function as spacers for the conductive particles larger than the conductive particles. That is, relatively small conductive particles having a size that contributes to connection may not be sufficiently sandwiched, but are expected to have an improved conduction performance because they become conduction points, and the sandwiching of conductive particles larger than this can be controlled within a certain range, so that it is expected that a favorable connection state can be conveniently obtained. This is because the metal-coated resin particles can be compressed, and therefore the state of compression can be controlled, and a further effect can be expected, which is preferable. In addition, the compression hardness may be reduced and the relatively small conductive particles may be set to a size for the purpose of anisotropic connection. Thus, by adjusting the compressive hardness of the conductive particles, options for obtaining the conduction performance are increased.

In addition, when the opening size S of a part of the full opening portion is different, regularity may be added. For example, the openings having the opening dimension S of the upper limit to the lower limit of the ratio of the opening diameters may be adjacent to each other, or the openings having the opening dimension S of the upper limit or the lower limit may be provided periodically in the longitudinal direction of the anisotropic conductive film. The periodic repeating unit can be set according to the width of the bump and the inter-bump gap (L/S). The conductive particles can be reliably arranged at the positions sandwiched by the bumps by setting the arrangement of the openings so that the conductive particles are present in the bumps in consideration of the width of the bumps and the gaps between the bumps. The distance between the openings can be set as appropriate, but can be set to 0.5 times or more, preferably equal times or more, the maximum conductive particle diameter for the purpose of arrangement. Further, if considering the case where relatively small conductive particles are present, the distance between the openings can be set to 1.5 times or more, preferably 2 times or more, the maximum conductive particle diameter for the purpose of arrangement. The size of the conductive particles and the size of the conductive particles having a smaller particle diameter among the conductive particles to be used may be appropriately set, and the ratio of the conductive particles to be present may be set.

In addition, in order to prevent a production failure of the connection structure and to ensure conduction, the minimum and maximum openings may be repeated in pairs. Alternatively, a plurality of openings having a size between the maximum and minimum sizes may be provided at the same time. In this case, the conductive particles of any size may be disposed in the anisotropic conductive film, or some of them may not be disposed. That is, even if any one is missing, the conduction can be satisfied if only one is present. As an example, the number of the cells is preferably 5 or more, more preferably 10 or more, and still more preferably 12. The distance between the conductive particles is preferably 0.5 times or more, more preferably equal times or more, the maximum conductive particle diameter. The arrangement is preferably substantially in the direction orthogonal to the longitudinal direction of the film. In order to complement a bump. When the conductive particles are arranged in this manner, any one of the conductive particles is supplemented at the time of connection in actual use, and therefore, occurrence of conduction failure can be avoided. For example, in the case of irregular shapes having uneven connection surfaces of terminals (for example, connection surfaces of Au bumps of an IC chip), it is expected that any one of the conductive particles will be appropriately supplemented if there is such a pair. If the bumps are allowed to be uneven, it is easy to obtain a cost advantage of the connecting body such as improvement of yield in manufacturing the bumps or enlargement of an allowable range of design quality. In addition, in the case of the Au bump, an effect of reducing the amount of Au used itself can be expected. In the case where the connection surface of the terminal has irregular uneven shape, the conductive particles can be compressed if they are metal-coated resin particles, and therefore, it is considered that the adjustment of the compression hardness can be applied. Further, when the surface area is increased by irregularly having such an irregular shape, it is presumed that if the conductive particles are different in size, the connection surface and the contact point of the conductive particles are increased as compared with the single size. When the connection surface of the terminal is smooth, the above-described effects can be expected by adjusting the particle diameter and the compression hardness. The above-described effects are based on the premise that the difference between the maximum and minimum conductive particle diameters or the hardness (compressive hardness) of the conductive particles is adjusted, and that the defects are avoided or within an allowable range by adjusting the arrangement position, number density, and the like of the conductive particles.

The method for storing the conductive particles in the openings is not particularly limited, and a known method can be used. For example, after spreading or applying a dry conductive particle powder or a dispersion liquid obtained by dispersing the dry conductive particle powder in a solvent onto the opening forming surface of the member 10, the surface of the opening forming surface can be scraped (squeegee) with a brush, a blade (blade), or the like, so that the conductive particles can be accommodated in the opening.

When the conductive particles are accommodated in the openings, as shown in fig. 1, the conductive particles 20a and 20b smaller than the opening size S are accommodated in the openings, but the conductive particles 20c larger than the opening size S are not accommodated in the openings, and thus screening for removing conductive particles having a large particle diameter is possible. This can reduce the manufacturing cost. Further, the cost can be reduced by recovering and reusing the scraped conductive particles.

(conductive particles)

As the conductive particles, conductive particles used in a known anisotropic conductive film can be appropriately selected and used. Examples thereof include metal particles such as nickel, copper, silver, gold, palladium, and the like; and metal-coated resin particles in which the surfaces of resin particles of polyamide, polybenzguanamine, or the like are coated with a metal such as nickel. The size of the conductive particles to be arranged is preferably 0.5 to 50 μm, and more preferably 1 to 30 μm, as an example.

The average particle diameter of the conductive particles supplied in the holding step (a) is preferably 0.5 to 50 μm in terms of handling property during production, and accounts for 90% or more of the total particle amount. In addition, it is preferable that conductive particles smaller than 1 μm and larger than 30 μm are removed in the holding step. The average particle diameter can be measured by an image-based particle size distribution meter as described above, or can be measured by surface observation (surface field observation) after the holding step.

In addition, the surface of the conductive particle is preferably coated with an insulator. By applying insulating coating or insulating particle treatment to the surface of the conductive particles, there is a surface coating which is easily peeled off and does not hinder anisotropic connection, and even if the opening size S is slightly larger than the conductive particles, the conductive particles are easily accommodated in the opening. The thickness of such a surface coating varies depending on the object to be connected, and therefore, there is no particular limitation as long as the connection is not hindered.

When the protrusions are provided on the surface of the conductive particles, the size of the protrusions is preferably within 20%, more preferably within 10% of the minimum conductive particle diameter. The number of the conductive particles is not particularly limited, and the conductive particles may be uniformly or dispersedly provided on the entire surface.

Further, since the conductive particles are mixed with conductive particles having different particle diameters, the conductive particles having relatively high compressibility are preferable. That is, the resin particles are preferably coated with a metal. The hardness varies depending on the connection object, and is not particularly limited, and as an example, the compression hardness (K value) at 20% deformation is 1000 to 8000N/mm²Can be selected from the range of (1), and preferably 1000 to 4000N/mm²The range of (1). In addition, conductive particles having different hardness may be intentionally mixed with each other.

Here, the compression hardness (K value) at 20% deformation is a load when the conductive particles are compressed by a load in one direction, and the particle diameter of the conductive particles becomes 20% shorter than the original particle diameter, and is a value calculated by the following formula (1), and becomes softer as the K value becomes smaller.

(wherein F represents a load at 20% compression deformation of the conductive particles

S: compressive displacement (mm)

R: radius (mm) of conductive particle)

(particle size distribution)

Fig. 2 (a) is a graph schematically showing the particle size distribution of the conductive particles supplied to the opening, and fig. 2 (B) is a graph schematically showing the particle size distribution of the conductive particles held in the opening. The particle size distribution chart is a number distribution of the maximum length (particle size) of 1000 or more, preferably 5000 or more conductive particles measured in the surface field observation of an optical microscope or a metal microscope. As shown in fig. 2 a, in the present method, since the conductive particles supplied to the opening portion may have a wide particle size distribution (broad), an effect of easily obtaining a balance between performance and cost can be expected by using conductive particles classified to the lower limit side of the particle size, and the like, and there is an advantage of increasing options of availability.

In the present embodiment, as shown in fig. 2 a, conductive particles having a wide particle size distribution are supplied to the opening, but as shown in fig. 2B, the particle size distribution chart of the conductive particles held in the opening (X axis: particle size [ μm ]; Y axis: number of particles) has a substantially infinite graph shape in which the slope is equal to or larger than the particle size having the maximum peak. In particular, the higher the ratio of the openings having the same size, the more the threshold value Da has a substantially infinite slope, which is substantially parallel to the Y axis. In the particle size distribution, the slope is substantially infinite, meaning that the particle size distribution has a straight line parallel to the Y axis, and includes a straight line approximately parallel to the Y axis. In addition, the particle size distribution may have a vertical tangent (vertical tangent) in other words, the slope is substantially infinite.

The particle size distribution of the conductive particles held in the openings is not limited to the graph shape shown in fig. 2 (B), and for example, the particle size Db having a slope at the maximum peak may be substantially infinite as shown in fig. 3, or some conductive particles having a particle size Dc having a slope substantially equal to or larger than infinite may be present as shown in fig. 4. As in the graph shapes, the particle diameter of the conductive particles has an upper limit, and the number of particles near the upper limit is large, so that the conductive particles that are insufficiently pressed are relatively reduced, and the occurrence of conduction failure can be suppressed.

As shown in fig. 5, the particle size distribution of the conductive particles held in the openings may have a shape having a plurality of peaks (bottoms) between peaks), and the slope may be substantially infinite in the particle size Dd. When there are a plurality of peaks, for example, when 2 kinds of metal-coated resin particles having different particle diameters are mixed, the conductive performance can be improved by adjusting the compression hardness of the metal-coated resin particles to increase the contact between the connecting surface and the conductive particles.

In addition, as the conductive particles to be supplied, conductive particles classified to the lower limit of the particle diameter are preferably used. Although the conductive particles having a small particle diameter do not contribute to connection and therefore do not have a great influence on conductivity, cost can be taken into consideration, and by using conductive particles classified to the lower limit side of the particle diameter in COG connection or the like requiring a relatively large amount of conductive particles, unnecessary overlapping of the conductive particles (overlapping of the conductive particles in the thickness direction) or the like can be suppressed. Further, by using conductive particles classified to the lower limit side of the particle diameter, a relatively small conductive particle having a size contributing to connection is held in the opening portion in a large number, and an effect of easily adjusting a spacer for controlling sandwiching of a conductive particle larger than a relatively small conductive particle having a size contributing to connection in a certain range can be expected.

As the method of grading the particle size on the lower limit side, various known techniques can be employed. For example, a wet-type classification method in which vibration having an amplitude of 0.2 to 40 μm is applied to conductive particles in a liquid and a sieve having a standard deviation of a minor axis of 10% or less is used can be mentioned (for example, jp 11-319626 a).

Fig. 6 (a) is a graph schematically showing the particle size distribution of the conductive particles classified on the lower limit side of the particle size supplied to the opening portion, and fig. 6 (B) is a graph schematically showing the particle size distribution of the conductive particles held in the opening portion. As shown in fig. 6a, in the particle size distribution chart (X axis: particle size [ μm ]; Y axis: amount of particles) of the supplied conductive particles, the range of the particle size having the slope not more than the maximum peak value is preferably a particle size De which is substantially infinite. Thus, as shown in FIG. 6B, the particle diameter distribution chart (X-axis: particle diameter [ μm ]; Y-axis: number of particles) of the conductive particles held in the opening portion has a particle diameter Df in which the range having an inclination not larger than the particle diameter of the maximum peak is substantially infinite, and a particle diameter Dg in which the range having an inclination not smaller than the particle diameter of the maximum peak is substantially infinite.

As shown in fig. 7, the particle diameter distribution chart (X axis: particle diameter [ μm ]; Y axis: number of particles) of the conductive particles held in the opening may have a threshold Dh substantially parallel to the Y axis, in which the range of the particle diameter having the slope at or below the maximum peak value is substantially infinite, and a threshold Di substantially parallel to the Y axis, in which the range of the particle diameter having the slope at or above the maximum peak value is substantially infinite.

In the case of using conductive particles classified to the lower limit side of the particle diameter, in order to make the pressure of the conductive particles uniform at the time of pressure bonding, it is preferable that 90% or more of the total number of the conductive particles held in the opening be present in the range of ± 30% of the average particle diameter, and more preferably 90% or more of the total number of the conductive particles be present in the range of ± 20% of the average particle diameter. By using conductive particles classified in advance to the lower limit side of the particle diameter in this way, the capture rate of the conductive particles captured at the bumps can be improved.

The present technology is not limited to the shapes of the graphs of the particle size distribution shown in fig. 2 to 7, and various shapes can be adopted within a range not departing from the gist of the present technology. For example, the diagram shape shown in fig. 7 is a bullet shape which is symmetrical to the left and right, but may not be symmetrical to the left and right.

[ transfer Process (B) ]

In the next transfer step (B), first, as shown in fig. 8, the adhesive film 30 is opposed to the surface of the member 10 having the opening formed therein.

As the adhesive film 30, a film used as an insulating adhesive layer in a known anisotropic conductive film can be appropriately selected and used. Examples of the curing type of the adhesive film 30 include a thermosetting type, a photo-curing type, and a photo-thermal curing type. For example, a photo radical polymerizable resin layer containing an acrylate compound and a photo radical polymerization initiator, a thermal radical polymerizable resin layer containing an acrylate compound and a thermal radical polymerization initiator, a thermal cationic polymerizable resin layer containing an epoxy compound and a thermal cationic polymerization initiator, a thermal anionic polymerizable resin layer containing an epoxy compound and a thermal anionic polymerization initiator, or the like, or a cured resin layer thereof can be used.

Hereinafter, an anion-curable adhesive film will be described as an example. The anion-curable adhesive film contains a film-forming resin, an epoxy resin and an anion polymerization initiator.

The film-forming resin corresponds to, for example, a high molecular weight resin having an average molecular weight of 10000 or more, and is preferably an average molecular weight of approximately 10000 to 80000 from the viewpoint of film-forming properties. 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 butyral resin, and these resins may be used alone or in combination of two or more. Among these, phenoxy resins are preferably used as appropriate from the viewpoint of film formation state, connection reliability, and the like.

The epoxy resin forms a 3-dimensional network structure and imparts excellent heat resistance and adhesiveness, and a solid epoxy resin and a liquid epoxy resin are preferably used in combination. Here, the solid epoxy resin means an epoxy resin that is solid at normal temperature. The liquid epoxy resin means an epoxy resin that is liquid at normal temperature. The normal temperature means a temperature range of 5 to 35 ℃ defined in jis z 8703.

The solid epoxy resin is not particularly limited as long as it is compatible with a liquid epoxy resin and is solid at room temperature, and examples thereof include a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a polyfunctional epoxy resin, a dicyclopentadiene type epoxy resin, a phenol novolac type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, and the like, and one kind or two or more kinds in combination can be used from among these. 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 ordinary temperature, and examples thereof include bisphenol a type epoxy resin, bisphenol F type epoxy resin, novolac phenol type epoxy resin, naphthalene type epoxy resin, and the like, and one kind or a combination of two or more kinds of these can be used alone. In particular, bisphenol a type epoxy resins are preferably used from the viewpoint of the adhesiveness, flexibility, and the like of the film.

As the anionic polymerization initiator, a commonly used and known curing agent can be used. Examples thereof include organic acid dihydrazide, dicyandiamide, an amine compound, a polyamidoamine (polyaminoamine) compound, a cyanate ester compound, a phenol resin, an acid anhydride, a carboxylic acid, a tertiary amine compound, imidazole, a Lewis acid, a Br Φ nsted acid salt, a polythiol curing agent, a urea resin, a melamine resin, an isocyanate compound, a blocked isocyanate compound, and the like, and one kind or two or more kinds of them may be used alone or in combination. Among these, it is preferable to use a microcapsule-type latent curing agent in which an imidazole modifier is used as a core and the surface thereof is coated with polyurethane.

Further, a stress buffer, a silane coupling agent, an inorganic filler, and the like may be mixed as necessary. Examples of the stress buffer include hydrogenated styrene butadiene block copolymers and hydrogenated styrene isoprene block copolymers. Examples of the silane coupling agent include epoxy compounds, methacryloxy compounds, ammonia compounds, vinyl compounds, mercapto compounds, sulfide compounds, and urea compounds. Examples of the inorganic filler include silica, talc, titanium oxide, calcium carbonate, and magnesium oxide.

The adhesive film 30 can be formed by forming a film of a coating composition containing the above-mentioned resin by a coating method, drying, or further curing, or by forming a film by a known method in advance. The thickness of the adhesive film 30 is preferably 1 to 30 μm, and more preferably 2 to 15 μm. Further, an insulating adhesive layer having such a thickness may be laminated as necessary. The adhesive film 30 is preferably formed on a release film 40 such as a polyethylene terephthalate film subjected to a release treatment.

The pressure may be applied to the adhesive film 30 from the side of the release film 40 to press the insulating adhesive layer into the opening, the conductive particles 20 may be embedded and attached to the surface of the insulating adhesive layer, or the conductive particles may be pressed into the insulating adhesive layer after transfer. The adhesive film 30 may be laminated before or after these steps as described above. This results in a structure in which the conductive particles 20 are aligned in a single layer in the planar direction of the insulating adhesive layer. In addition, in order to satisfy the supplement at the time of connection, it is preferable that the conductive particles are located in a position close to the outermost surface of the adhesive film 30.

The minimum melt viscosity of the entire insulating adhesive layer is preferably 100 to 10000 Pa/sec. Within this range, the conductive particles can be precisely arranged in the insulating adhesive layer, and the trapping property of the conductive particles can be prevented from being impaired by the flow of the resin for press-fitting at the time of anisotropic conductive connection. As an example, the minimum melt viscosity can be determined by using a measuring plate having a diameter of 8mm, using a rotary rheometer (TA instruments Co., Ltd.), with a temperature rise rate of 10 ℃/min and a measuring pressure of 5g kept constant.

< 2. Anisotropic conductive film >

The anisotropic conductive film according to the present embodiment includes an insulating adhesive formed in a film shape; and a plurality of conductive particles arranged in the insulating adhesive under the surface visual field, wherein in the particle size distribution chart (X axis: particle size [ mu ] m; Y axis: number of particles) of the conductive particles, the range of the particle size with the slope more than the maximum peak value is in a chart shape with an infinite size. The X-axis particle size is preferably in the range of 1 to 30 μm. The particle size distribution chart is a number distribution of the maximum length (particle size) of 1000 or more, preferably 5000 or more conductive particles measured in the surface field observation of an optical microscope or a metal microscope.

In addition, the particle size distribution chart of the conductive particles (X-axis: particle size [ mu ] m)](ii) a Y-axis: number of particles) has a wide shape (broadd). Here, the wide shape means a particle diameter D of 10% cumulative number from the side where the particle diameter is small in cumulative distribution₁₀With a particle diameter D of 90% by number₉₀The difference is greater than 1 μm. Alternatively, the broad shape means the particle diameter D of 10% cumulative number from the side where the particle diameter is small in cumulative distribution₁₀With a particle diameter D of 90% by number₉₀The difference is more than 25% of the average particle diameter. The cumulative 10% of the number refers to the number of particles (particle diameter) of 10% in the order of size (particle diameter) with the number of total particles measured as 100%.

In the above-described manufacturing method, the conductive particles accommodated in the opening portion are conductive particles disposed in the anisotropic conductive film in a surface field of view. That is, as described with reference to the particle size distribution diagrams shown in fig. 2 to 7, the anisotropic conductive film according to the present embodiment is configured such that conductive particles on the upper limit side of the particle size are selected, and the particle size of the conductive particles has an upper limit, and the number of particles near the upper limit is large, thereby suppressing the occurrence of conduction failure. Further, the conductive particles having a small particle diameter do not contribute to the connection, and therefore do not affect the conductivity much. Further, conductive particles having a wide particle size distribution, that is, relatively low-cost conductive particles that are not graded or are minimally graded, can be used, and therefore, this can contribute to reduction in material cost. Further, by adjusting the size or hardness (compressive hardness) of the conductive particles as described above, an effect of improving the conduction characteristics can be expected.

When the conductive particles are not graded or not graded to the minimum, the conductive particles arranged in the anisotropic conductive film may have a particle size distribution diagram (X-axis: particle size [ μm ]; Y-axis: number of particles) in which a plurality of peaks are present (bottom portions between peaks). This is because the conductive particle size before the gradation does not exist in any way, but there is no particular problem because it does not cause any trouble as described above as long as it does not overlap in the thickness direction at the time of connection.

In addition, when conductive particles having different hardness are mixed, the conductive particles may be intentionally formed into such a shape. For example, if the conductive particles having relatively hard hardness are set to have a relatively small peak value of particle diameter, and the conductive particles having less hard hardness are set to have a relatively large peak value of particle diameter, the effect of improving the replenishing efficiency can be expected. In addition, the press-in of the conductive particles can be adjusted, which contributes to conduction stability. In this case, the particle size of each conductive particle may be measured before the holding step, and the particle size may be adjusted to have a substantially suitable peak value by simply screening the particles. Alternatively, conductive particles each having a different particle size distribution may be prepared and mixed so as to have a substantially suitable peak.

In the particle size distribution chart (X-axis: particle size [ μm ]; Y-axis: number of particles) of the conductive particles disposed in the anisotropic conductive film, it is preferable that the range of the particle size in which the slope is equal to or less than the maximum peak value is substantially infinite. Thus, as shown in FIG. 6B, the conductive particles held in the opening have a particle diameter distribution chart (X-axis: particle diameter [ μm ]; Y-axis: number of particles) in which the range of particle diameters having an inclination equal to or smaller than the maximum peak is substantially infinite particle diameter Df and the range of particle diameters having an inclination equal to or larger than the maximum peak is substantially infinite particle diameter Dg. In order to make the pressure of the conductive particles uniform when pressure-bonded, it is preferable that 90% or more of the total number of particles is present in a range of ± 30% of the average particle diameter, and it is more preferable that 90% or more of the total number of particles is present in a range of ± 20% of the average particle diameter. By using conductive particles classified in advance to the lower limit side of the particle diameter in this way, the capture rate of the conductive particles captured at the bumps can be improved.

However, in the holding step (a), when the openings of the member are covered with conductive particles having a large particle diameter, the conductive particles are removed by subsequent wiping, and there are openings in which the conductive particles are not held, and "missing" of the conductive particles occurs in the anisotropic conductive film. The omission is not problematic as long as it is in a range that does not hinder the anisotropic connection.

In addition, the allowable range of the leakage rate of the anisotropic conductive film varies depending on the bump layout of the connection object. The leak rate is a ratio of the number of conductive particles existing in the length of the film in the width direction to the length of the film in the length direction. As an example, if the bumps are arranged at a high density like COG, the leak rate needs to be reduced, but as an example, if the bump area is relatively large like FOG, the leak rate is not so large.

In addition, it is preferable that there is no bias in omission. For the same reason as described above, the COG requirement is small, and the FOG is large to some extent.

The length and width of the ACF used for each 1 time are various according to the connection object,however, the maximum size of about 20 mm. times.2 mm is generally the upper limit. Therefore, if the conductive particle size is 10 μm or less, 40mm will be formed²The continuous area of 2 times, preferably 5 times, and more preferably 10 times as large as the area of the entire anisotropic conductive film, provided that 1mm is arbitrarily extracted from the continuous area²Without significant differences (bias), no obstacles are presented to the connection. The 1mm²It is preferable to extract (discontinuously) 10 sites of an area of 50 μm in the film longitudinal direction and 200 μm in the film width direction. In general, the width direction of the film is the longitudinal direction of the bump for anisotropic connection, and the length direction of the film is the width direction of the bump, and therefore, the area to be evaluated is preferably rectangular in shape with a short length direction of the film.

When the conductive particle size is larger than 10 μm and not larger than 30 μm, the area of the whole film is maintained as it is, the extracted area is 2 times in the film length direction and width direction, 10 discrete portions are extracted for 100 μm × 400 μm area, and the total of 4mm is evaluated²And (4) finishing. In addition, when the width of the film is less than 400 μm, the rectangular shape may be appropriately changed.

The bias of the omission is not preferable if concentrated omission occurs in a small number density of specific portions. Such omission preferably has a minimum value of 50% or more, more preferably 60% or more, and still more preferably 70% or more, relative to the maximum value of the number density of 10 sites of 50 × 200 μm or 100 × 400 μm.

As an example of the missing bias, the total of the arbitrarily extracted areas is preferably (1 mm) in terms of the number density of the conductive particles in the entire area²) A difference of + -30%, more preferably a difference of + -20%. If the value is within the above range, it is easy to achieve a balance between cost and performance.

(film roll body)

The anisotropic conductive film is preferably a film wound body wound around a roll (roll) in order to continuously connect electronic components. The length of the wound film body may be 5m or more, and preferably 10m or more. There is no particular upper limit, and from the viewpoint of handling property of the shipment, it is preferably 5000m or less, more preferably 1000m or less, and still more preferably 500m or less.

The film wound body may be connected to an anisotropic conductive film shorter than the entire length by a connection tape. The connecting portion may be present at a plurality of positions, may be present regularly, or may be present randomly. The thickness of the interface tape is not particularly limited as long as it does not hinder performance, but is preferably 10 to 40 μm since an excessively thick thickness may affect extrusion or blocking (blocking) of the resin. The width of the film is not particularly limited, but is 0.5 to 5mm as an example.

According to such a film wound body, continuous anisotropic connection can be achieved, and the cost reduction of the connected body can be facilitated.

< 3 > method for producing connection structure and connection structure

The method for manufacturing a connection structure according to the present technology includes: a disposing step (S1) of disposing a 1 st electronic component and a 2 nd electronic component with an anisotropic conductive film interposed therebetween; and a curing step (S2) of bonding the 2 nd electronic component to the 1 st electronic component by a bonding tool and curing the anisotropic conductive film, wherein the anisotropic conductive film includes: an insulating adhesive formed in a film shape; and a plurality of conductive particles arranged in the insulating adhesive under the surface visual field, wherein in the particle size distribution chart (X axis: particle size [ mu ] m; Y axis: number of particles) of the conductive particles, the range of the particle size with the slope more than the maximum peak value is in a chart shape with infinite degree.

Fig. 9 is a sectional view schematically showing the method of manufacturing the connected body according to the present embodiment, fig. 9 (a) shows the arrangement step (S1), and fig. 9 (B) shows the curing step (S2). Note that since the anisotropic conductive adhesive film is the same as described above, the description thereof is omitted here.

[ disposing step (S1) ]

As shown in fig. 9 a, in the disposing step (S1), the 1 st electronic component 50 and the 2 nd electronic component 70 are disposed with the anisotropic conductive film 60 interposed therebetween, wherein the anisotropic conductive film 60 includes an insulating adhesive formed in a film shape and a plurality of conductive particles disposed on the insulating adhesive in a surface view, and a range of a particle diameter having a slope equal to or larger than a maximum peak value in a particle diameter distribution diagram (X-axis: particle diameter [ μm ]; Y-axis: number of particles) of the conductive particles is substantially infinite in a diagram shape.

The 1 st electronic component 50 includes a 1 st terminal row 51. The 1 st electronic component 50 is not particularly limited and can be appropriately selected according to the purpose. Examples of the 1 st electronic component 50 include LCD (Liquid Crystal Display) panels, Flat Panel Displays (FPDs) such as organic el (oled), transparent substrates such as touch panels, and Printed Wiring Boards (PWB). The material of the printed wiring board is not particularly limited, and for example, epoxy glass such as FR-4 base material, plastic such as thermoplastic resin, ceramics, and the like can be used. The transparent substrate is not particularly limited as long as it has high transparency, and examples thereof include a glass substrate and a plastic substrate.

The 2 nd electronic component 70 includes a 2 nd terminal row 71 facing the 1 st terminal row 51. The 2 nd electronic component 70 is not particularly limited and can be appropriately selected according to the purpose. Examples of the 2 nd electronic component 70 include an IC (Integrated Circuit), a Flexible Printed Circuit (FPC), a Tape Carrier Package (TCP) substrate, and a cof (chip On film) for mounting an IC On an FPC.

[ curing step (S2) ]

As shown in fig. 9B, in the curing step (S2), the 2 nd electronic component 70 is pressed against the 1 st electronic component 50 by the pressing tool 80. Thereby, the 2 nd electronic component is sufficiently pressed by the pressure bonding tool 80, and the resin is cured in a state where the conductive particles 61 are sandwiched between the terminals.

According to the method for producing a connection structure, excellent conductivity can be obtained as in the case of using an anisotropic conductive film containing conductive particles graded in advance.

Further, a connection structure according to the present technology includes: 1 st electronic component; a 2 nd electronic component; and an adhesive film to which the 1 st electronic component and the 2 nd electronic component are adhered, the adhesive film being formed by curing an anisotropic conductive film, the anisotropic conductive film having an insulating adhesive formed in a film shape and a plurality of conductive particles arranged on the insulating adhesive in a surface view field, and having a substantially infinite graph shape in a range of a particle diameter having a slope equal to or larger than a maximum peak value in a particle diameter distribution graph (X-axis: particle diameter [ mu ] m; Y-axis: number of particles) of the conductive particles.

According to such a connection structure, excellent conductivity can be obtained as in the case of bonding with an anisotropic conductive film containing conductive particles graded in advance.

The present technology is not limited to the application to the above-described method for manufacturing a connection structure, and can be applied to a case where IC chips or wafers are stacked (stack) and multilayered.

< 4. method for producing filler-provided film and filler-provided film

In the above-described method for producing an anisotropic conductive film, a filler-disposed film in which a filler is disposed in a surface field of view can be produced by using the same filler as the conductive particles instead of the conductive particles.

That is, the method for producing a filler-disposed film according to the present embodiment includes: a holding step of supplying a filler having a plurality of particle diameters to a member having a plurality of openings, and holding the filler in the openings; and a transfer step of transferring the filler held in the opening portion to the adhesive film, wherein in a particle size distribution chart (X-axis: particle size [ mu ] m; Y-axis: number of particles) of the filler held in the opening portion, a range of particle sizes having a slope of not less than a maximum peak value is substantially infinite in a chart shape. By thus classifying the filler using a member having a plurality of openings, the manufacturing cost of the filler placement film can be reduced. In addition, in this method, since the filler supplied to the opening portion may have a wide particle size distribution (a wide range), an effect of easily obtaining a balance between performance and cost can be expected by using conductive particles or the like classified to the lower limit side of the particle size, and there is an advantage of increasing options of availability.

As the filler, one or both of an inorganic filler and an organic filler can be used in accordance with the use of the filler for disposing the film. Examples of the inorganic filler include silica, calcium carbonate, talc, barium sulfate, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, titanium oxide, zinc oxide, iron oxide, mica, and the like. Examples of the organic filler include known resin fillers such as silicone resin, fluororesin, and polybutadiene resin, and rubber particles.

For example, when the filler arrangement film is used as a gap spacer, examples of the filler include silica, calcium carbonate, a known resin filler, rubber particles, and the like, and the filler arrangement film functions as an excellent gap spacer because the particle diameters of the filler are uniform. In addition, for example, when the filler-disposed film is used as an optical member for light diffusion, matting, gloss, or the like, examples of the filler include titanium oxide, zinc oxide, iron oxide, or a known resin filler, and the filler-disposed film can obtain excellent optical performance because the filler is disposed at a predetermined position in a surface field of view. In addition, for example, when the filler-disposed film is used as a design member, the filler includes a coloring filler (whether inorganic or organic), and the filler-disposed film can obtain excellent design properties because the filler is disposed at a predetermined position in a surface field of view.

The member having a plurality of openings and the adhesive film are the same as those described in the above-described method for producing an anisotropic conductive film, and therefore, the description thereof is omitted here.

The filler arrangement film according to the present embodiment includes: an insulating adhesive formed in a film shape; and a plurality of fillers arranged in the insulating adhesive under the surface visual field, wherein in the particle size distribution chart (X axis: particle size [ mu ] m; Y axis: number of particles) of the fillers, the range of the particle size with the slope more than the maximum peak value is in a chart shape with infinite degree in nature. The filler arrangement film is arranged under the surface field of view without a filler having a large particle diameter in the particle diameter distribution of the filler, and therefore can be used for applications to be adopted as a conductive member, or a gap spacer, an optical member, a design member, and the like, in addition to a method of using an anisotropic conductive film known as conductive particles, for example.

Examples

< 5. example >

Hereinafter, examples of the present technology will be described. In this example, an anisotropic conductive film was produced by supplying conductive particles mixed at a predetermined ratio (converted in number) to a resin mold having an opening array pattern formed therein to hold the conductive particles in openings, and transferring the conductive particles held in the openings to an adhesive film. Then, the anisotropic conductive film was evaluated in a graded manner. Further, a connection structure was produced using an anisotropic conductive film, and the connection structure was subjected to conductivity evaluation, complementary evaluation, and short-circuit evaluation. Further, the present technology is not limited to these embodiments. For example, the same effects as the results of the ranking evaluation of the anisotropic conductive film can be obtained also in the examples of the filler-disposed film and the method for producing the filler-disposed film using the resin particles instead of the conductive particles.

[ production of Anisotropic conductive film ]

(preparation of resin mold)

The angle theta formed by the lattice axis and the short side direction of the anisotropic conductive film is 15 DEG, the distance between particles is equal to 2 times of the particle diameter of the conductive particles, and the number density of the conductive particles is 28000 pieces/mm²In the embodiment (1), a mold having projections conforming to the arrangement pattern was produced. The projections of the mold were square with a size of 3.3. mu. m.times.3.3 μm, and the pitch at the center point was 6 μm, which was 2 times the average conductive particle size of 3 μm. The height of the projection (i.e., the depth of the opening) was set to 3.5 μm. A known pellet (pellet) of transparent resin is poured into the mold in a molten state, cooled, and solidified, thereby forming a resin mold in which an opening arrangement pattern is formed. The depth of the opening of the obtained resin mold is substantially the same as the height of the convex portion.

(preparation of insulating resin layer A and insulating resin layer A)

A resin composition A having the following formulation was coated on a PET film having a thickness of 50 μm by a bar coater, and dried in an oven at 80 ℃ for 5 minutes to form an insulating resin layer A having a thickness of 4 μm on the PET film.

Resin composition A (insulating resin layer A)

Phenoxy resin (YP-50, new day tienjin chemical (ltd)): 30 parts by mass; epoxy resin (jER 828, mitsubishi chemical (ltd)): 40 parts by mass; cationic curing agent (SI-60L, Sanxin chemical industry Co., Ltd.): 2 parts by mass; bulking agent (AEROSIL RX300, japan AEROSIL (strain)): 30 parts by mass.

A resin composition B having a composition described below was applied to a PET film having a thickness of 50 μm by a bar coater, and dried in an oven at 80 ℃ for 5 minutes to form an insulating resin layer B having a thickness of 14 μm on the PET film.

Resin composition B (insulating resin layer B)

Phenoxy resin (YP-50, new day tienjin chemical (ltd)): 30 parts by mass; phenoxy resin (FX-316 ATM55, new day tientian chemical (ltd)): 30 parts by mass; epoxy resin (jER 828, mitsubishi chemical (ltd)): 40 parts by mass; cationic curing agent (SI-60L, Sanxin chemical industry Co., Ltd.): 2 parts by mass.

(preparation of 2-layer Anisotropic conductive film)

As the conductive particles, 3 μm metal-coated resin particles (AUL 703, average particle diameter 3 μm, hereinafter referred to as "3 μm diameter particles") and 5 μm metal-coated resin particles (AUL 705, average particle diameter 5 μm, hereinafter referred to as "5 μm diameter particles") were prepared.

Conductive particles a were obtained by weighing the particles having a diameter of 3 μm in terms of number at 80% and the particles having a diameter of 5 μm at 20% in a container and sufficiently mixing the weighed particles. The mixture was confirmed by drawing out a small amount of the mixture, spreading the mixture in the form of a coherent film, and observing the film with a metal microscope. Further, the mixing was repeated 3 to 10 times, and it was confirmed that the mixture was uniform.

The conductive particles A are filled in the recesses of a resin mold having an opening array pattern formed therein, covered with the insulating resin layer A, and pressed at 60 ℃ and 0.5MPa to adhere the conductive particles A to the insulating resin layer. Then, the insulating resin layer A was peeled off from the resin mold, and the conductive particles on the insulating resin layer A were pressed into the insulating resin layer A by pressing (pressing conditions: 60 to 70 ℃ C., 0.5 MPa), thereby producing a conductive particle-containing layer. An anisotropic conductive film A having a thickness of 18 μm was produced by laminating a layer containing no conductive particles, which is composed of an insulating resin layer B, on the surface of the conductive particle-containing layer on which the conductive particles A are present at 60 ℃ and 0.5 MPa.

Conductive particles B mixed so that 3 μm diameter particles account for 75% by number and 5 μm diameter particles account for 25%; conductive particles C mixed so that the number of particles having a diameter of 3 μm is 50% in terms of the number and the number of particles having a diameter of 5 μm is 50%; conductive particles D mixed so that the number of particles having a diameter of 3 μm is 40% and the number of particles having a diameter of 5 μm is 60%; and conductive particles E having a diameter of 3 μm of 100% in terms of number were produced in the same manner as described above.

[ grading evaluation of Anisotropic conductive film ]

The film surfaces of the conductive particle-containing layers of the anisotropic conductive films a to E were observed with a metal microscope, and particle omission in alignment was evaluated. The anisotropic conductive films A to E were observed in 10 discrete portions over an area of 50 μm in the film longitudinal direction and 200 μm in the film width direction, and the observation was repeated in 5 portions for a total of 5mm²The area of (a).

As a result, the anisotropic conductive films a to D showed the same performance as that of the anisotropic conductive film E using only 3 μm diameter particles as described later, although the particles were missing in the alignment as the number ratio of the 3 μm diameter particles of the conductive particles used was lower, and the range of practical use was not problematic.

The particle size distribution of the conductive particles in the conductive particle-containing layers of the anisotropic conductive films a to E was measured by a particle size distribution measuring apparatus (FPIA-3000 (MALVERN corporation)).

As a result, the particle size distribution of all the conductive particles of the anisotropic conductive films a to E has a substantially infinite graph shape with a slope of about 3 μm, and the maximum peak is less than 3 μm. That is, the graph shape is similar to a straight line parallel to the Y axis in a particle diameter of about 3 μm. In addition, it was confirmed that 90% or more of the total number of conductive particles was present in the range of ± 30% of the average particle diameter in all of the anisotropic conductive films a to E. Strictly speaking, since the conductive particles larger than 3 μm are present, the graph shape of the portion where the value of the Y axis between 3 μm and 3.3 μm on the X axis is close to zero (the portion on the side slightly more positive than 0 when X is 3 to 3.3) has a shape of only a little shoulder (shoulder) as shown in fig. 4.

[ evaluation of conductivity of connection Structure ]

Anisotropic conductive films a to E were sandwiched between the IC for conductivity evaluation and the glass substrate, and heated and pressed (180 ℃, 60MPa, 5 seconds) to prepare a connection structure for conductivity evaluation. Then, the on-resistance of each connection structure was measured after a reliability test in which the connection structure was initially connected and left to stand in a constant temperature bath at a temperature of 85 ℃ and a humidity of 85% RH for 500 hours.

As a result, in all the connection structures using the anisotropic conductive films a to E, the initial on-resistance was less than 0.5 Ω, and the on-resistance after the reliability test was less than 5 Ω. That is, the anisotropic conductive films a to D showed the same performance as the anisotropic conductive film E using only particles having a diameter of 3 μm, and it was found that there was no problem in practical use.

IC for conductivity evaluation:

the external form is 1.8 multiplied by 20.0mm

Thickness of 0.5mm

The specification size of the salient point is 30 multiplied by 85 mu m; the distance between the salient points is 50 mu m; bump height 15 μm

Glass substrate (ITO wiring):

1737F, CORNING, Inc. of glass

Outer diameter of 30X 50mm

Thickness of 0.5mm

And (6) wiring an electrode ITO.

[ evaluation of complement of connection Structure ]

The captured state of the conductive particles was subjected to indentation inspection using a connection structure for conductivity evaluation. As a result, it was confirmed that at least 3 or more conductive particles were formed into independent indentations for each bump in all of the anisotropic conductive films a to E. In addition, as for the trapping number, the trapping number tends to increase as the mixing ratio of the particles having a diameter of 3 μm increases, and the trapping number is the largest only with the anisotropic conductive film E having a diameter of 3 μm.

[ short-circuit evaluation of connection Structure ]

For each connection structure for conductivity evaluation, the number of channels for 100 inter-bump short circuits was measured and used as the number of short circuits. As a result, all the connection structures using the anisotropic conductive films a to E are not short-circuited.

Further, anisotropic conductive films a to E were sandwiched between an IC for short-circuit occurrence rate evaluation and a glass substrate having a pattern corresponding to the IC for evaluation, and heated and pressed (180 ℃, 60MPa, 5 seconds) to prepare a connection structure for conductivity evaluation. Then, the number of channels short-circuited between bumps was defined as the short-circuit number, and the short-circuit occurrence rate calculated as "the number of short-circuits occurring/7.5 μm total number of voids" was determined.

As a result, the occurrence rate of short circuits was less than 50ppm in all the connection structures using the anisotropic conductive films A to E. Further, if the short-circuit occurrence rate is less than 50ppm, there is no problem in practical use.

IC (comb TEG (test Element group)) for evaluating short-circuit incidence

The external form is 1.5 multiplied by 13mm

Thickness of 0.5mm

The bump size is gold plating, the height is 15 μm, the size is 25X 140 μm, and the distance between bumps is 7.5 μm.

[ comprehensive evaluation ]

In any of the evaluations of the gradation of the anisotropic conductive film, the conductivity of the connection structure, the complementary evaluation, and the short circuit evaluation, it was found that the anisotropic conductive films a to D to which the present technology is applied are equivalent to the anisotropic conductive film E using only particles having a diameter of 3 μm, and there is no problem in actual use. That is, by applying this technique, conductive particles having a wide particle size distribution can be used, and the manufacturing cost can be reduced. From the results of the evaluation of the anisotropic conductive film by the scale, it was found that the same effects can be obtained even with the filler-disposed film.

In the above-described embodiment, the conductive particles having a relatively large particle size are removed, but the conductive particles having a relatively small particle size may be removed in advance by a known method. Examples of the method for removing the conductive particles having a small particle diameter include a wet-type classification method in which vibration having an amplitude of 0.2 to 40 μm is applied to the conductive particles in a liquid and a standard deviation of a short diameter is 10% or less.

Description of the reference symbols

10 a member; 20 conductive particles; 30 an adhesive film; 40 peeling off the film; 50 the 1 st electronic component; 51 the 1 st terminal row; 60 an anisotropic conductive film; 61 conductive particles; 70 a 2 nd electronic component; 71 the 2 nd terminal row; 80 crimping tool.

Claims (14)

1. A method for manufacturing an anisotropic conductive film,

comprising: a holding step of supplying conductive particles having a plurality of particle diameters to a member having a plurality of openings and holding the conductive particles in the openings; and a transfer step of transferring the conductive particles held in the opening portion to an adhesive film,

in the particle size distribution chart of the conductive particles held in the opening, the range of the particle size with the slope more than the maximum peak value is in a chart shape with the slope being infinite, wherein, the X axis is the particle size and the unit is μm; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the conductive particles and the number of conductive particles near the upper limit is large.

2. The method for manufacturing an anisotropic conductive film according to claim 1, wherein,

a particle diameter distribution chart of the conductive particles supplied in the holding step, wherein a range having a slope of not more than a maximum peak particle diameter is substantially infinite particle diameter, wherein an X-axis is a particle diameter and a unit thereof is μm; the Y axis represents the number of particles.

3. The method for manufacturing an anisotropic conductive film according to claim 1 or 2, wherein,

the surfaces of the plurality of conductive particles supplied in the holding step are covered with an insulator.

4. An anisotropic conductive film is provided, which comprises a base film,

the disclosed device is provided with: an insulating adhesive formed in a film shape; and

a plurality of conductive particles disposed in the insulating adhesive under a surface field of view,

in the particle size distribution chart of the conductive particles, the range of the particle size with the slope more than the maximum peak value is in a chart shape with the virtually infinite degree, wherein, the X axis is the particle size and the unit is mum; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the conductive particles and the number of conductive particles near the upper limit is large.

5. The ACF of claim 4 wherein,

a particle size distribution chart of the conductive particles, wherein the range of the slope below the particle size of the maximum peak is substantially infinite, wherein the X axis is the particle size and the unit thereof is mum; the Y axis represents the number of particles.

6. The acf of claim 4 or 5 wherein,

in a particle size distribution diagram of the conductive particles, a diagram shape having a plurality of peaks is formed, wherein an X axis is a particle size in μm; the Y axis represents the number of particles.

7. An anisotropic conductive film wound body, wherein the anisotropic conductive film according to any one of claims 4 to 6 is wound around a winding core.

8. A method for manufacturing a connection structure, comprising:

a placement step of placing a 1 st electronic component and a 2 nd electronic component with an anisotropic conductive film interposed therebetween, the anisotropic conductive film including an insulating adhesive formed in a film shape and a plurality of conductive particles placed on the insulating adhesive in a surface field of view, wherein a range of a particle diameter having a slope equal to or larger than a maximum peak value in a particle diameter distribution diagram of the conductive particles is substantially infinite in a diagram shape, and an X-axis is a particle diameter and a unit thereof is μm; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the conductive particles and the number of conductive particles near the upper limit is large; and

and a curing step of bonding the 2 nd electronic component to the 1 st electronic component by a bonding tool and curing the anisotropic conductive film.

9. A connection structure is provided with:

1 st electronic component; a 2 nd electronic component; and an adhesive film for adhering the 1 st electronic component and the 2 nd electronic component,

the adhesive film is formed by curing an anisotropic conductive film, the anisotropic conductive film comprises an insulating adhesive formed in a film shape and a plurality of conductive particles arranged on the insulating adhesive under a surface visual field, and in a particle size distribution chart of the conductive particles, a range of a particle size with a slope of more than or equal to a maximum peak value is in a chart shape with an infinite size, wherein an X axis is a particle size and a unit thereof is mum; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the conductive particles and the number of conductive particles near the upper limit is large.

10. A method for producing a filler-containing film,

comprising: a holding step of supplying a filler having a plurality of particle diameters to a member having a plurality of openings, and holding the filler in the openings; and a transfer step of transferring the filler held in the opening portion to an adhesive film,

in the particle size distribution chart of the filler held in the opening, the range of the particle size with the slope of the maximum peak value is in a chart shape with the slope of the maximum peak value being substantially infinite, wherein the X axis is the particle size and the unit thereof is μm; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large.

11. A filler arrangement film is provided with:

an insulating adhesive formed in a film shape; and

a plurality of fillers disposed in the insulating adhesive under a surface field of view,

in the particle size distribution chart of the filler, the range of the particle size with the slope more than the maximum peak value is in a chart shape with the virtually infinite degree, wherein, the X axis is the particle size and the unit is μm; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large.

12. An anisotropic conductive film wound body, wherein the filler arrangement film according to claim 11 is wound around a core.

13. A method for manufacturing a connection structure, comprising:

a placement step of placing a 1 st electronic component and a 2 nd electronic component with a filler placement film interposed therebetween, the filler placement film including an insulating adhesive formed in a film shape and a plurality of fillers disposed on the insulating adhesive in a surface view, wherein a range of a particle diameter having a slope of a maximum peak or more in a particle diameter distribution diagram of the fillers is substantially infinite in a diagram shape, and wherein an X-axis represents a particle diameter and a unit thereof is μm; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large; and

a curing step of bonding the 2 nd electronic component to the 1 st electronic component by a bonding tool and curing the filler arrangement film,

a filler-disposed film having a particle diameter such that a range of a slope equal to or larger than a particle diameter having a maximum peak value is substantially infinite in a particle diameter distribution chart of the filler, wherein an X-axis represents a particle diameter and a unit thereof is [ mu ] m; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large.

14. A connection structure is provided with:

1 st electronic component; a 2 nd electronic component; and an adhesive film for adhering the 1 st electronic component and the 2 nd electronic component,

the adhesive film is a cured filler-disposed film, which is provided with an insulating adhesive formed in a film shape and a plurality of fillers disposed on the insulating adhesive in a surface view, and in which a range of particle diameters having slopes of not less than a maximum peak value in a particle diameter distribution chart of the fillers is in a substantially infinite chart shape, wherein an X-axis represents a particle diameter and a unit thereof is [ mu ] m; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large,

a filler-disposed film having a particle diameter such that a range of a slope equal to or larger than a particle diameter having a maximum peak value is substantially infinite in a particle diameter distribution chart of the filler, wherein an X-axis represents a particle diameter and a unit thereof is [ mu ] m; the Y axis represents the number of particles so that there is an upper limit on the particle diameter of the filler and the number of fillers in the vicinity of the upper limit is large.