WO2018051799A1

WO2018051799A1 - Filler-containing film

Info

Publication number: WO2018051799A1
Application number: PCT/JP2017/031318
Authority: WO
Inventors: 怜司塚尾; 三宅　健
Original assignee: デクセリアルズ株式会社
Priority date: 2016-09-13
Filing date: 2017-08-31
Publication date: 2018-03-22
Also published as: TWI759326B; TW202227543A; JP7352114B2; CN116003858A; JP2022126655A; KR20190010879A; TW201825563A; KR20220080204A

Abstract

The purpose of the invention is, in a filler-containing film in which filler is dispersed in a resin layer, to limit filler flow due to unnecessary flow of the resin layer during pressure bonding of the filler-containing film and an object. Said filler-containing film 10A has a filler dispersion layer 3 in which filler 1 is dispersed in the resin layer 2. The surface of the resin layer 2 near the filler 1 has depressions 2b, 2c with respect to a tangent plane to the resin layer 2 at the center between adjacent fillers 1. The ratio (La/D) of the layer thickness La of the resin layer 2 to the particle diameter D of the filler 1 is preferably 0.6-10. The ratio (Lb/D) of the deepest distance Lb for filler 1 from the tangent plane at the center between adjacent fillers 1 for the surface of the resin layer 2 in which the depressions 2b, 2c are formed to the filler particle diameter D is preferably 60% to 105%.

Description

Filler-containing film

The present invention relates to a filler-containing film.

Filler-containing films in which filler is dispersed in the resin layer are used in a wide variety of applications such as matte films, condenser films, optical films, label films, anti-static films, anisotropic conductive films ( Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4). When a filler-containing film is pressure-bonded to an article that is an adherend of the filler-containing film, it is optically possible to suppress unnecessary resin flow of the resin forming the filler-containing film and suppress uneven distribution of the filler. Desirable in terms of characteristics, mechanical characteristics, or electrical characteristics. In particular, when conductive particles are included as fillers and the filler-containing film is an anisotropic conductive film used for mounting electronic components such as IC chips, it is insulative so that it can cope with the high mounting density of electronic components. When the conductive particles are dispersed in the resin layer at a high density, the conductive particles dispersed at a high density move unnecessarily due to the resin flow when the electronic component is mounted and are unevenly distributed between the terminals, causing a short circuit.

On the other hand, in order to reduce shorts and improve workability when temporarily bonding an anisotropic conductive film to a substrate, a photocurable resin layer in which conductive particles are embedded in a single layer, an insulating adhesive layer, An anisotropic conductive film in which is laminated is proposed (Patent Document 5). As a method of using this anisotropic conductive film, temporary pressure bonding is performed in a state where the photocurable resin is uncured and has tackiness, and then the photocurable resin layer is photocured to fix the conductive particles, and then Then, the substrate and the electronic component are finally bonded.

In order to achieve the same object as that of Patent Document 5, an anisotropic conductive film having a three-layer structure in which a first connection layer is sandwiched between a second connection layer and a third connection layer mainly made of an insulating resin. Have also been proposed (Patent Documents 6 and 7). Specifically, the anisotropic conductive film of Patent Document 6 has a structure in which the first connection layer has conductive particles arranged in a single layer in the plane direction on the second connection layer side of the insulating resin layer, The insulating resin layer thickness in the central region between the adjacent conductive particles is thinner than the insulating resin layer thickness in the vicinity of the conductive particles. On the other hand, the anisotropic conductive film of Patent Document 7 has a structure in which the boundary between the first connection layer and the third connection layer is undulated, and the first connection layer is on the third connection layer side of the insulating resin layer. In this plane direction, the conductive particles are arranged in a single layer, and the insulating resin layer thickness in the central region between adjacent conductive particles is thinner than the insulating resin layer thickness in the vicinity of the conductive particles.

JP 2006-15680 A JP2015-138904A JP2013-103368A JP 2014-183266 A JP 2003-64324 A JP 2014-060150 A Japanese Patent Application Laid-Open No. 2014-060151

However, in the anisotropic conductive film described in Patent Document 5, the conductive particles easily move during temporary pressure bonding of the anisotropic conductive connection, and the precise arrangement of the conductive particles before the anisotropic conductive connection is made after the anisotropic conductive connection. There is a problem that it cannot be maintained or the distance between the conductive particles cannot be sufficiently separated. In addition, after temporarily bonding such an anisotropic conductive film to the substrate, the photocurable resin layer is photocured, and the photocured resin layer in which the conductive particles are embedded is bonded to the electronic component. There is a problem that the conductive particles are difficult to be captured at the ends of the bumps, and an excessively large force is required to push the conductive particles, and the conductive particles cannot be pushed in sufficiently. Moreover, in patent document 5, examination from the viewpoint of the exposure of the electrically-conductive particle from a photocurable resin layer etc. is not fully made for the improvement of indentation of an electrically-conductive particle.

Therefore, instead of the photo-curable resin layer, conductive particles are dispersed in an insulating resin layer that becomes highly viscous at the heating temperature during anisotropic conductive connection, thereby suppressing the fluidity of the conductive particles during anisotropic conductive connection. In addition, it is conceivable to improve workability when the anisotropic conductive film is attached to the electronic component. However, even if the conductive particles are precisely arranged in such an insulating resin layer, if the resin layer flows during anisotropic conductive connection, the conductive particles also flow at the same time. It is difficult to sufficiently reduce the short circuit, and it is difficult to maintain the initial precise arrangement of the conductive particles after anisotropic conductive connection and to keep the conductive particles in a separated state.

In addition, in the case of the anisotropic conductive film having a three-layer structure described in Patent Documents 6 and 7, although there is no problem with respect to the basic anisotropic conductive connection characteristics, since it has a three-layer structure, the manufacturing cost is low. From the viewpoint, it is required to reduce the number of manufacturing steps. In addition, in the vicinity of the conductive particles on one side of the first connection layer, the whole or part of the first connection layer is greatly raised along the outer shape of the conductive particles, and the insulating resin layer itself forming the first connection layer is flat. However, since the conductive particles are held in the raised portions, there is a concern that there are many design restrictions for improving the holding of the conductive particles and the capturing property by the terminals.

On the other hand, the present invention provides a filler-containing film in which fillers such as conductive particles are dispersed in a resin layer, and does not require a three-layer structure. Even if the whole or a part of the filler is not raised larger than the outer shape of the filler, it is possible to suppress the flow of the filler due to the unnecessary flow of the resin layer when the filler-containing film and the article are pressure-bonded. Is formed as an anisotropic conductive film, the unnecessary flow of the conductive particles is suppressed at the time of thermocompression bonding between the anisotropic conductive film and the electronic component, the trapping property of the conductive particles at the terminal is improved, and a short circuit is caused. The problem is to reduce.

The present inventor has obtained the following knowledge about the relationship between the surface shape of the resin layer near the filler and the viscosity of the resin layer, with respect to the filler-containing film having a filler dispersion layer in which fillers such as conductive particles are dispersed in the resin layer. That is, in the anisotropic conductive film described in Patent Document 5, the surface of the insulating resin layer (that is, the photocurable resin layer) on the side where the conductive particles are embedded is flat, i) When fillers such as conductive particles are exposed from the resin layer, if the surface of the resin layer around the filler is recessed with respect to the tangential plane of the resin layer at the center between adjacent fillers, Unnecessary insulation that may interfere with the bonding between the filler and the article when the filler-containing film is pressed onto the article and the filler-containing film is joined to the article due to the dent becoming part of the surface of the resin layer chipped. The resin can be reduced, and (ii) when the filler is embedded in the resin layer without being exposed from the resin layer, the filler is embedded in the resin layer on the surface of the resin layer immediately above the filler. And traces of When undulations such as undulations are formed, the amount of resin is reduced in the undulations of the undulations, which makes it easier for the filler to be pushed in by the article when crimping the filler-containing film to the article. (Iii) Therefore, when two opposing articles are pressure-bonded via the filler-containing film, the filler sandwiched between the opposing articles and the article are well connected, in other words, the filler trapping property in the article, Alternatively, the present inventors have found that the consistency of the arrangement state before and after the pressure-bonding of the filler sandwiched between articles is improved, and that the product inspection of the filler-containing film and the confirmation of the use surface are facilitated. In addition, it has been found that such a dent in the resin layer can be formed by adjusting the viscosity of the resin layer into which the filler is pressed when the filler dispersion layer is formed by pressing the filler into the resin layer.

The present invention is based on the above-described findings, and is a filler-containing film having a filler dispersion layer in which a filler is dispersed in a resin layer,
The surface of the resin layer in the vicinity of the filler provides a filler-containing film having a recess with respect to the tangent plane of the resin layer at the center between adjacent fillers. In particular, in this recess, the surface of the resin layer around the filler is Provided is a film that is lacking with respect to the tangent plane or has a resin amount in the resin layer immediately above the filler that is less than when the surface of the resin layer immediately above the filler is on the tangential plane. .

Further, the present invention is a method for producing a filler-containing film having a step of forming a filler dispersion layer in which a filler is dispersed in a resin layer,
The step of forming the filler dispersion layer is a step of holding the filler on the surface of the resin layer;
Having a step of pushing the filler held on the surface of the resin layer into the resin layer;
In the step of holding the filler on the surface of the resin layer, the filler is held on the surface of the resin layer in a state where the filler is dispersed,
In the step of pushing the filler into the resin layer, the viscosity of the resin layer when pushing the filler so that the surface of the resin layer in the vicinity of the filler has a dent with respect to the tangent plane of the resin layer at the center between adjacent fillers, Provided is a method for producing a filler-containing film that adjusts the indentation speed or temperature, and in particular, as the dent, the surface of the resin layer around the filler is missing from the tangential plane, or the resin layer directly above the filler A method for producing a filler-containing film is provided in which a less amount of the resin is formed than when the surface of the resin layer immediately above the filler is on the tangential plane.

The filler-containing film of the present invention has a filler dispersion layer in which a filler is dispersed in a resin layer. In this filler dispersion layer, the surface of the resin layer in the vicinity of the filler has a dent with respect to the tangential plane of the resin layer at the center between adjacent fillers. That is, when the filler is exposed from the resin layer, there is a dent in the surface of the resin layer around the exposed filler, and the resin layer is not in contact with the tangential plane at the dent. The amount of resin has been reduced. In addition, when the filler is buried in the resin layer without being exposed from the resin layer, the surface of the resin layer immediately above the filler has a dent, and the amount of resin in the dent portion is reduced with respect to the tangential plane. ing.

For this reason, if there is a dent in the resin layer around the filler exposed from the resin layer, the resin flow is reduced when the filler-containing film is pressure-bonded to the article due to the reduced amount of resin in the dent. At the same time, the filler is easily pressed against the article. Furthermore, when two articles are pressure-bonded via the filler-containing film, the resin is unlikely to hinder the filler from being sandwiched or the filler from being flattened. Moreover, since the resin amount around the filler is reduced by the depression, the resin flow that leads to unnecessary flow of the filler is reduced. Therefore, the trapping property of the filler in the article is improved, and in particular, when the filler-containing film is configured as an anisotropic conductive film, the conduction reliability is improved by improving the trapping property of the conductive particles in the terminal.

Also, if the resin layer immediately above the filler embedded in the resin layer has a dent, the pressing force from the article is likely to be applied to the filler when the filler-containing film is pressure-bonded to the article. In addition, the resin flow that leads to unnecessary flow of the filler is reduced by the amount of the resin immediately above the filler being reduced by the depression. Therefore, in this case as well, the trapping property of the filler in the article is improved, especially when the filler-containing film is configured as an anisotropic conductive film, that is, when the conductive particles are dispersed in the insulating resin layer as a filler. The conduction reliability is improved by improving the trapping property of the conductive particles at the terminal.

Thus, according to the filler-containing film of the present invention, the filler capturing property is improved, and the filler is difficult to flow on the article, so that the arrangement of the filler can be precisely controlled. Therefore, when the filler-containing film is an anisotropic conductive film, the arrangement of the conductive particles can be precisely controlled with respect to the terminals. For example, a fine pitch with a terminal width of 6 μm to 50 μm and a space between terminals of 6 μm to 50 μm. Can be used to connect electronic components. Further, when the size of the conductive particles is less than 3 μm (for example, 2.5 to 2.8 μm), the effective connection terminal width (the width of the overlapping portion in plan view among the widths of the pair of terminals opposed at the time of connection) ) Is 3 μm or more, and the shortest distance between terminals is 3 μm or more, it is possible to connect electronic components without causing a short circuit.

In addition, since the arrangement of the conductive particles can be precisely controlled, when connecting electronic components with normal pitch, the layout of the conductive particle arrangement area and the area where the number density of the conductive particles is changed is the terminal of various electronic parts. It is possible to correspond to the layout of.

Furthermore, in the filler-containing film of the present invention, if there is a dent in the resin layer immediately above the filler embedded in the resin layer, the position of the filler can be clearly seen by observing the appearance of the filler-containing film. It becomes easy to identify the front and back of the film surface. For this reason, when the filler-containing film is pressure-bonded to the article, it is easy to confirm the use surface of which side of the filler-containing film is bonded to the article. Similar advantages are obtained when producing filler-containing films.

In addition, according to the filler-containing film of the present invention, it is not always necessary to photocure the resin layer in order to fix the filler arrangement. Can have sex. For this reason, when the final pressure bonding is performed after the filler-containing film and the article are temporarily pressure-bonded, workability at the time of temporary pressure-bonding is improved, and workability is improved also when the article is finally pressure-bonded after the temporary pressure bonding.

On the other hand, according to the manufacturing method of the present invention, the viscosity, indentation speed, or temperature of the resin layer when the filler is embedded in the resin layer is adjusted so that the above-described dent is formed in the resin layer. Therefore, the filler-containing film of the present invention that exhibits the above-described effects can be easily manufactured.

FIG. 1A is a plan view showing the arrangement of conductive particles of an anisotropic conductive film 10A of an example which is an embodiment of the filler-containing film of the present invention. FIG. 1B is a cross-sectional view of an anisotropic conductive film 10A of an example which is an embodiment of the filler-containing film of the present invention. FIG. 2 is a cross-sectional view of an anisotropic conductive film 10B of an example which is an embodiment of the filler-containing film of the present invention. FIG. 3A is a cross-sectional view of an anisotropic conductive film 10C of an example which is an embodiment of the filler-containing film of the present invention. FIG. 3B is a cross-sectional view of the anisotropic conductive film 10 </ b> C ′ of an example which is an aspect of the filler-containing film of the present invention. FIG. 4 is a cross-sectional view of an anisotropic conductive film 10D of an example which is an embodiment of the filler-containing film of the present invention. FIG. 5 is a cross-sectional view of an anisotropic conductive film 10E of an embodiment which is an aspect of the filler-containing film of the present invention. FIG. 6 is a cross-sectional view of an anisotropic conductive film 10F of an example which is an embodiment of the filler-containing film of the present invention. FIG. 7 is a cross-sectional view of an anisotropic conductive film 10G of an example which is an embodiment of the filler-containing film of the present invention. FIG. 8 is a cross-sectional view of an anisotropic conductive film 10X serving as a comparative example of the filler-containing film of the present invention. FIG. 9 is a cross-sectional view of an anisotropic conductive film 10Y serving as a comparative example of the filler-containing film of the present invention. FIG. 10 is a cross-sectional view of an anisotropic conductive film 10H of an example which is an embodiment of the filler-containing film of the present invention. FIG. 11 is a cross-sectional view of an anisotropic conductive film 10I of an example which is an embodiment of the filler-containing film of the present invention. FIG. 12A is a cross-sectional photograph of an anisotropic conductive film of an example which is an embodiment of the filler-containing film of the present invention. FIG. 12B is a cross-sectional photograph of an anisotropic conductive film of an example which is an embodiment of the filler-containing film of the present invention. FIG. 12C is a cross-sectional photograph of an anisotropic conductive film serving as a comparative example of the filler-containing film of the present invention. FIG. 13A is a top view photograph of an anisotropic conductive film of an example which is an embodiment of the filler-containing film of the present invention. FIG. 13B is a top view photograph of an anisotropic conductive film of an example which is an embodiment of the filler-containing film of the present invention.

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

<Overall configuration of filler-containing film>
FIG. 1A is a plan view for explaining the arrangement of fillers in a filler-containing film 10A according to one embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX. This filler-containing film 10 </ b> A is used as an anisotropic conductive film, in which conductive particles as a filler 1 are dispersed in an insulating resin layer 2.

In the present invention, the filler-containing film 10A such as an anisotropic conductive film can be in the form of a long film having a length of, for example, 5 m or more, and can be a wound body wound around a winding core.

The filler-containing film 10 </ b> A is composed of a filler dispersion layer 3, and the filler dispersion layer 3 is regularly dispersed with the filler 1 exposed on one side of the resin layer 2. The fillers 1 are not in contact with each other in the plan view of the film, the fillers 1 are regularly dispersed in the film thickness direction without overlapping each other, and the single layer filler layer in which the positions of the fillers 1 in the film thickness direction are aligned. Is configured.

A recess 2b is formed on the surface 2a of the resin layer 2 around each filler 1 with respect to the tangential plane 2p of the resin layer 2 at the center between adjacent fillers. As will be described later, in the filler-containing film of the present invention, a recess 2c may be formed on the surface of the resin layer immediately above the filler 1 embedded in the resin layer 2 (FIGS. 4 and 6).

<Dispersed state of filler>
The filler dispersion state in the present invention includes a state where the fillers 1 are randomly dispersed and a state where the fillers 1 are regularly arranged. In either case, it is preferable from the viewpoint of capture stability that the positions in the film thickness direction are aligned. Here, the position of the filler 1 in the film thickness direction being aligned is not limited to the position of the filler 1 being aligned at a single depth in the film thickness direction. It includes a mode in which filler 1 is present in each of the vicinity.

Further, in order to make the optical, mechanical or electrical characteristics of the filler-containing film uniform, especially when the filler-containing film is an anisotropic conductive film, the filler 1 is a plan view of the film from the viewpoint of suppressing short circuit. It is preferable to arrange regularly. The arrangement mode can be determined according to the article to which the filler-containing film is pressure-bonded. For example, in the anisotropic conductive film, the arrangement mode of the conductive particles can be determined by the layout of the terminals and bumps. There is no limitation in particular about this aspect. For example, it can be a square lattice arrangement as shown in FIG. 1A in a plan view of the film. In addition, examples of the regular arrangement of the filler include a lattice arrangement such as a rectangular lattice, an oblique lattice, a hexagonal lattice, and a triangular lattice. A plurality of grids having different shapes may be combined. As an arrangement mode of the fillers, particle rows in which fillers are linearly arranged at predetermined intervals may be arranged in parallel at predetermined intervals. Moreover, the aspect which the missing | missing of a filler exists regularly in the predetermined direction of a film may be sufficient.

By making the fillers 1 non-contact with each other and having a regular arrangement such as a lattice shape, when the filler-containing film is pressure-bonded to the article, pressure is evenly applied to the fillers 1 to reduce variations in the connection state. it can. In addition, it is possible to manage lots by allowing fillers to be repeatedly removed in the longitudinal direction of the film, or by gradually increasing or decreasing the locations where fillers are missing in the longitudinal direction of the film. It is also possible to impart traceability (a property that enables tracking) to the connected connection structure. This is also effective for prevention of counterfeiting, authenticity determination, prevention of unauthorized use, etc. of the filler-containing film and the connection structure using the same.

Therefore, in the anisotropic conductive film, since the conductive particles are regularly arranged, variation in conduction resistance can be reduced when electronic parts are connected by the anisotropic conductive film. In addition, it is more preferable that the conductive particles are regularly arranged in a plan view of the film and that the positions in the film thickness direction are aligned in order to achieve both capture stability and short circuit suppression.

On the other hand, when the space between the terminals of the electronic parts to be connected is wide and short-circuiting is difficult to occur, the conductive particles may be randomly dispersed without regularly arranging them.

When the fillers are regularly arranged in the filler-containing film, the lattice axis or the arrangement axis of the arrangement may be parallel to the longitudinal direction of the film or the direction perpendicular to the longitudinal direction, and intersect with the longitudinal direction of the film. It can be determined according to the article to be connected, and when the filler-containing film is an anisotropic conductive film, it can be determined according to the terminal width, terminal pitch, and the like. For example, when an anisotropic conductive film for fine pitch is used, the lattice axis A of the conductive particles 1 is skewed with respect to the longitudinal direction of the anisotropic conductive film 10A as shown in FIG. The angle θ formed by the longitudinal direction of the terminals 20 connected by the film 10A (the short direction of the film) and the lattice axis A is preferably 6 ° to 84 °, more preferably 11 ° to 74 °.

In the filler-containing film, the distance between the fillers can also be determined according to the article to be connected. When the filler-containing film is an anisotropic conductive film, the interparticle distance of the conductive particles 1 is determined by the anisotropic conductive film. It can be appropriately determined according to the size of the terminal to be connected and the terminal pitch. For example, when an anisotropic conductive film is made compatible with fine pitch COG (Chip-On-Glass), the distance between the nearest particles should be 0.5 times or more the conductive particle diameter D in order to prevent occurrence of short circuit. Preferably, it is more preferable to make it larger than 0.7 times. On the other hand, the upper limit of the distance between the nearest particles can be determined according to the purpose of the filler-containing film. For example, from the viewpoint of difficulty in manufacturing the filler-containing film, the distance between the nearest particles is preferably the conductive particle diameter D. It can be 100 times or less, more preferably 50 times or less. Further, from the viewpoint of the capturing property of the conductive particles 1 at the terminal at the time of anisotropic conductive connection, the distance between the nearest particles is preferably 4 times or less of the conductive particle diameter D, more preferably 3 times or less. preferable.

In the filler-containing film of the present invention, the filler area occupancy calculated by the following formula is preferably 35% or less, more preferably 0.3 to 30%.
Area occupancy (%) = [number density of fillers in plan view] × [average of area in plan view of one filler] × 100

Here, as the measurement area of the number density of the filler, a plurality of rectangular areas each having a side of 100 μm or more are arbitrarily set (preferably 5 or more, more preferably 10 or more), and the total area of the measurement area is 2 mm. ^Two or more are preferable. What is necessary is just to adjust suitably the magnitude | size and number of each area | region according to the state of number density. For example, as an example of the case where the number density of anisotropic conductive films for fine pitch is relatively large, a metal microscope is used for 200 places (2 mm ² ) in an area of 100 μm × 100 μm arbitrarily selected from anisotropic conductive films. The number density is measured using an observation image obtained by, for example, and averaged to obtain the “number density of conductive particles in plan view” in the above formula. A region having an area of 100 μm × 100 μm is a region where one or more bumps exist in a connection object having a space between bumps of 50 μm or less.

The number density value is not particularly limited as long as the area occupancy is within the above range, but when the filler-containing film is an anisotropic conductive film, the number density is practically 30 pieces / mm. ² or more, preferably 150 to 70000 pieces / mm ² , particularly in the case of fine pitch use, preferably 6000 to 42000 pieces / mm ² , more preferably 10,000 to 40000 pieces / mm ² , and still more preferably 15000-35000 pieces / mm ² .

The number density of the filler may be obtained by observing with a metal microscope as described above, or may be obtained by measuring an observation image with image analysis software (for example, WinROOF, Mitani Corporation, etc.). The observation method and the measurement method are not limited to the above.

In addition, the average of the planar view area of one filler can be obtained by measuring an observation image using a metal microscope on the film surface or an electron microscope such as SEM. Image analysis software may be used. The observation method and the measurement method are not limited to the above.

The area occupancy ratio is an index of thrust required for the pressing jig to press the filler-containing film to the article, and is preferably 35% or less, more preferably 0.3 to 30%. This is due to the following reason. That is, conventionally, in order to correspond to a fine pitch in anisotropic conductive films, the distance between conductive particles has been reduced and the number density has been increased as long as no short circuit occurs. However, when the number density is increased in this way, the number of terminals of the electronic component is increased, and the total area of connection per electronic component is increased, so that the anisotropic conductive film is pressed against the electronic component to be pressed. There is a concern that the thrust required for the tool becomes large, and there is a problem that the pressing is insufficient with the conventional pressing jig. The problem of thrust required for such a pressing jig is not limited to anisotropic conductive films, but is common to all filler-containing films. On the other hand, by setting the area occupation ratio to 35% or less, more preferably 30% or less as described above, the thrust required for the pressing jig to press the filler-containing film to the article is reduced. It becomes possible to suppress.

<Filler>
In the present invention, the filler 1 is a known inorganic filler (metal, metal oxide, metal nitride, etc.), organic filler (resin particles, rubber particles, etc.), organic material, etc., depending on the use of the filler-containing film. Fillers mixed with inorganic materials (for example, particles whose core is formed of a resin material and metal-plated on the surface (metal-coated resin particles), those in which insulating fine particles are attached to the surface of conductive particles, conductive particles The surface is suitably selected according to the performance required for applications such as hardness and optical performance. For example, in an optical film or a matte film, a silica filler, a titanium oxide filler, a styrene filler, an acrylic filler, a melamine filler, various titanates, and the like can be used. For capacitor films, titanium oxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate and mixtures thereof Etc. can be used. The adhesive film can contain polymer rubber particles, silicone rubber particles, and the like. The anisotropic conductive film contains conductive particles. Examples of the conductive particles include metal particles such as nickel, cobalt, silver, copper, gold, and palladium, alloy particles such as solder, metal-coated resin particles, and metal-coated resin particles having insulating fine particles attached to the surface. . Two or more kinds can be used in combination. Among these, the metal-coated resin particles are preferable in that the resin particles repel after being connected, so that the contact with the terminal is easily maintained and the conduction performance is stabilized. In addition, the surface of the conductive particles may be subjected to an insulation treatment that does not hinder the conduction characteristics by a known technique. The filler mentioned according to the above-mentioned use is not limited to the said use, and may contain the filler containing film of another use as needed. Moreover, in the filler-containing film for each application, two or more kinds of fillers can be used in combination as required.

The particle diameter D of the filler 1 is appropriately determined according to the use of the filler-containing film. For example, an anisotropic conductive film is preferably 1 μm or more and 30 μm or less, more preferably, in order to be able to cope with variations in wiring height, to suppress increase in conduction resistance, and to suppress occurrence of short circuit. 3 μm or more and 9 μm or less.

The particle diameter D of the filler before being dispersed in the resin layer 2 can be measured with a general particle size distribution measuring apparatus, and the average particle diameter can also be obtained with a particle size distribution measuring apparatus. An example of the particle size distribution measuring apparatus is FPIA-3000 (Malvern). On the other hand, the particle diameter D of the filler in the filler-containing film (that is, the particle diameter D after the filler is dispersed in the resin layer) can be obtained from observation with an electron microscope such as SEM. In this case, it is desirable that the number of samples for measuring the particle diameter D is 200 or more. Moreover, when the shape of a filler is not spherical, the diameter of the shape imitating the maximum length or a sphere based on a planar image or a cross-sectional image can be used as the particle diameter D of the filler.

In addition, for example, in order to improve the insulating properties of the conductive particles of the anisotropic conductive film, when using a filler having insulating fine particles attached to its surface, the particle size of the filler in the present invention is the surface The particle diameter does not include the insulating fine particles.

<Resin layer>
(Viscosity of resin)
In the present invention, the minimum melt viscosity of the resin layer 2 is not particularly limited, and can be appropriately determined according to the use of the filler-containing film, the method for producing the filler-containing film, and the like. For example, as long as the above-mentioned dents 2b and 2c can be formed, depending on the manufacturing method of a filler containing film, it can also be set as about 1000 Pa.s. On the other hand, as a method for producing a filler-containing film, when the filler is held on the surface of the resin layer in a predetermined arrangement and the filler is pushed into the resin layer, the resin layer is the minimum from the point that the film can be formed. The melt viscosity is preferably 1100 Pa · s or more.

Further, as described in the method for producing a filler-containing film described later, a dent 2b is formed around the exposed portion of the filler 1 pushed into the resin layer 2 as shown in FIG. From the point of forming the recess 2c just above the filler 1 pushed into the resin layer 2 as shown, preferably 1500 Pa · s or more, more preferably 2000 Pa · s or more, still more preferably 3000 to 15000 Pa · s, even more. The pressure is preferably 3000 to 10,000 Pa · s. This minimum melt viscosity can be obtained by using a rotary rheometer (manufactured by TA Instruments Inc.) as an example, keeping it constant at a measurement pressure of 5 g, and using a measurement plate having a diameter of 8 mm, and more specifically in the temperature range. At 30 to 200 ° C., it can be obtained by setting the temperature rising rate 10 ° C./min, the measurement frequency 10 Hz, and the load fluctuation 5 g with respect to the measurement plate.

By setting the minimum melt viscosity of the resin layer 2 to a high viscosity of 1500 Pa · s or more, it is possible to suppress unnecessary movement of the filler for pressure-bonding the filler-containing film to the article. In this case, it is possible to prevent the conductive particles to be sandwiched between the terminals during anisotropic conductive connection from flowing due to resin flow.

Further, when the filler dispersion layer 3 of the filler-containing film 10 </ b> A is formed by pressing the filler 1 into the resin layer 2, the resin layer 2 when the filler 1 is pressed is such that the filler 1 is exposed from the resin layer 2. When the resin layer 2 is pressed into the resin layer 2, the resin layer 2 is plastically deformed to form a highly viscous viscous material that forms a recess 2 b (FIG. 1B) in the resin layer 2 around the filler 1, or When the filler 1 is pushed into the resin layer 2 without being exposed from the resin layer 2, a dent 2 c (FIG. 6) is formed on the surface of the resin layer 2 immediately above the filler 1. Use a highly viscous material. Therefore, the lower limit of the viscosity of the resin layer 2 at 60 ° C. is preferably 3000 Pa · s or more, more preferably 4000 Pa · s or more, further preferably 4500 Pa · s or more, and the upper limit is preferably 20000 Pa · s or less. Preferably it is 15000 Pa.s or less, More preferably, it is 10000 Pa.s or less. This measurement is performed by the same measurement method as that for the minimum melt viscosity, and can be obtained by extracting a value at a temperature of 60 ° C.

The specific viscosity of the resin layer 2 when the filler 1 is pushed into the resin layer 2 is preferably at least 3000 Pa · s, more preferably 4000 Pa, depending on the shape and depth of the recesses 2b and 2c to be formed. S or more, more preferably 4500 Pa · s or more, and the upper limit is preferably 20000 Pa · s or less, more preferably 15000 Pa · s or less, and even more preferably 10000 Pa · s or less. Further, such a viscosity is preferably obtained at 40 to 80 ° C., more preferably 50 to 60 ° C.

As described above, the depression 2b (FIG. 1B) is formed around the filler 1 exposed from the resin layer 2, thereby preventing the filler 1 from being flattened when the filler-containing film is bonded to the article. The resistance received from the resin is reduced compared to the case where there is no dent 2b. For this reason, when the filler-containing film is an anisotropic conductive film, the conductive particles are easily sandwiched between the terminals at the time of anisotropic conductive connection, whereby the conduction performance is improved and the trapping property is improved.

Further, since the recess 2c (FIGS. 4 and 6) is formed on the surface of the resin layer 2 immediately above the filler 1 that is buried without being exposed from the resin layer 2, compared to the case where there is no recess 2c. The pressure during pressure bonding of the filler-containing film to the article is likely to concentrate on the filler 1. Therefore, when the filler-containing film is an anisotropic conductive film, the conductive particles are easily sandwiched between the terminals at the time of anisotropic conductive connection, so that the trapping property is improved and the conduction performance is improved.

(Layer thickness of resin layer)
In the filler-containing film of the present invention, the ratio (La / D) between the layer thickness La of the resin layer 2 and the particle diameter D of the filler 1 is preferably 0.6 to 10. Here, the particle diameter D of the filler 1 means the average particle diameter. If the layer thickness La of the resin layer 2 is too large, the filler tends to be misaligned when the filler-containing film is pressed onto the article. Therefore, when the filler-containing film is an optical film, the optical characteristics vary. Further, when the filler-containing film is an anisotropic conductive film, the trapping property of the conductive particles at the terminal is lowered during anisotropic conductive connection. This tendency is remarkable when La / D exceeds 10. Therefore, La / D is more preferably 8 or less, and even more preferably 6 or less. On the other hand, if the layer thickness La of the resin layer 2 is too small and La / D is less than 0.6, it is difficult to maintain the filler 1 in a predetermined particle dispersion state or a predetermined arrangement by the resin layer 2. Therefore, when the filler-containing film is an anisotropic conductive film, particularly when the terminal to be connected is a high density COG, the ratio (La) of the layer thickness La of the insulating resin layer 2 to the particle diameter D of the conductive particles 1 / D) is preferably 0.8-2. On the other hand, when it is considered that the risk of occurrence of a short circuit is low due to the bump layout of electronic components to be connected, the lower limit of the ratio (La / D) may be set to 0.25 or more.

(Composition of resin layer)
In the present invention, the resin layer 2 can be formed from a thermoplastic resin composition, a high viscosity adhesive resin composition, and a curable resin composition. The resin composition constituting the resin layer 2 is appropriately selected according to the use of the filler-containing film, and whether or not the resin layer 2 is insulative is also determined according to the use of the filler-containing film.

Here, the curable resin composition can be formed from, for example, a thermopolymerizable composition containing a thermopolymerizable compound and a thermal polymerization initiator. You may make a thermopolymerizable composition contain a photoinitiator as needed.

When a thermal polymerization initiator and a photopolymerization initiator are used in combination, one that also functions as a photopolymerizable compound may be used as the thermopolymerizable compound, and a photopolymerizable compound is contained separately from the thermopolymerizable compound. May be. Preferably, a photopolymerizable compound is contained separately from the thermally polymerizable compound. For example, a cationic curing initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermopolymerizable compound, a photo radical initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound.

As the photopolymerization initiator, a plurality of types that react to light having different wavelengths may be contained. Thereby, at the time of manufacture of a filler containing film, the wavelength used by the photocuring of resin for film-forming a resin layer and the photocuring of resin when a filler containing film is crimped | bonded to articles | goods can be used properly.

In photocuring during the production of the filler-containing film, all or part of the photopolymerizable compound contained in the resin layer can be photocured. By this photocuring, the arrangement of the filler 1 in the resin layer 2 is maintained or fixed, and it is expected that the short circuit is suppressed and the capturing property is improved. Moreover, you may adjust suitably the viscosity of the resin layer in the manufacturing process of a filler containing film by this photocuring.

The amount of the photopolymerizable compound in the resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. This is because when the amount of the photopolymerizable compound is too large, the thrust required for pressing when the filler-containing film is pressure-bonded to the article increases.

Examples of the thermally polymerizable composition include a thermal radical polymerizable acrylate composition containing a (meth) acrylate compound and a thermal radical polymerization initiator, and a thermal cationic polymerizable epoxy system containing an epoxy compound and a thermal cationic polymerization initiator. Examples thereof include compositions. Instead of the thermal cationic polymerizable epoxy composition containing a thermal cationic polymerization initiator, a thermal anionic polymerizable epoxy composition containing a thermal anionic polymerization initiator may be used. In addition, a plurality of types of polymerizable compositions may be used in combination as long as there is no particular problem. Examples of combined use include combined use of a thermal cationic polymerizable compound and a thermal radical polymerizable compound.

Here, as the (meth) acrylate compound, a conventionally known thermal polymerization type (meth) acrylate monomer can be used. For example, a monofunctional (meth) acrylate monomer or a bifunctional or higher polyfunctional (meth) acrylate monomer can be used.

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

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

Examples of the epoxy compound include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a modified epoxy resin thereof, an alicyclic epoxy resin, and the like. it can. In addition to the epoxy compound, an oxetane compound may be used in combination.

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators for epoxy compounds can be employed. For example, iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc. that generate an acid by heat are used. In particular, an aromatic sulfonium salt showing a good potential with respect to temperature can be preferably used.

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

As the thermal anionic polymerization initiator, a commonly used known curing agent can be used. For example, organic acid dihydrazide, dicyandiamide, amine compound, polyamidoamine compound, cyanate ester compound, phenol resin, acid anhydride, carboxylic acid, tertiary amine compound, imidazole, Lewis acid, Bronsted acid salt, polymercaptan curing agent , Urea resin, melamine resin, isocyanate compound, block isocyanate compound, and the like. Among these, one kind can be used alone, or two or more kinds can be used in combination. Among these, it is preferable to use a microcapsule type latent curing agent having an imidazole-modified product as a core and a surface thereof coated with polyurethane.

The thermopolymerizable composition preferably contains a film-forming resin and a silane coupling agent. Examples of the film-forming resin include phenoxy resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide resin, polyolefin resin, and the like. be able to. Among these, a phenoxy resin can be preferably used from the viewpoint of film forming property, workability, and connection reliability. The weight average molecular weight is preferably 10,000 or more. Examples of the silane coupling agent include an epoxy silane coupling agent and an acrylic silane coupling agent. These silane coupling agents are mainly alkoxysilane derivatives.

In addition to the filler 1 described above, an insulating filler may be contained in the thermopolymerizable composition in order to adjust the melt viscosity. Examples of this include silica powder and alumina powder. The insulating filler is preferably a fine filler having a particle size of 20 to 1000 nm, and the blending amount is 5 to 50 parts by mass with respect to 100 parts by mass of a thermally polymerizable compound (photopolymerizable composition) such as an epoxy compound. Is preferred. The insulating filler contained separately from the filler 1 is preferably used when the use of the filler-containing film is an anisotropic conductive film, but may not be insulating depending on the use. For example, a conductive fine filler may be used. You may make it contain. When the filler-containing film is an anisotropic conductive film, the resin layer forming the filler dispersion layer appropriately contains a finer insulating filler (so-called nanofiller) different from the filler 1 as necessary. Can do.

The filler-containing film of the present invention includes a filler, a softening agent, an accelerator, an anti-aging agent, a colorant (pigment, dye), an organic solvent, an ion catcher agent, etc. in addition to the above-described insulating or conductive filler. You may make it contain.

<Position of filler in thickness direction of resin layer>
In the filler-containing film of the present invention, the filler 1 in the thickness direction of the resin layer 2 may be exposed from the resin layer 2 as described above, and is embedded in the resin layer 2 without being exposed. The distance of the deepest part of the filler from the tangential plane 2p in the center between adjacent fillers on the surface 2a on which the resin layer recesses 2b and 2c are formed (hereinafter referred to as an embedding amount). It is preferable that the ratio (Lb / D) between Lb and the particle diameter D of the filler 1 (hereinafter referred to as embedding rate) is 60% or more and 105% or less.

By setting the embedding rate (Lb / D) to 60% or more, the filler 1 is maintained in a predetermined particle dispersion state or a predetermined arrangement by the resin layer 2, and by setting it to 105% or less, a filler-containing film The amount of resin in the resin layer that acts to cause the filler to flow unnecessarily at the time of pressure bonding with the article can be reduced.

In the present invention, the embedding rate (Lb / D) is 80% or more, preferably 90% or more, more preferably 96% or more of the total number of fillers contained in the filler-containing film. It means that the value is (Lb / D). Therefore, the embedding rate of 60% or more and 105% or less means that the embedding rate of 80% or more, preferably 90% or more, more preferably 96% or more of the total number of fillers contained in the filler-containing film is 60% or more and 105%. % Or less.

As described above, since the embedding rate (Lb / D) of all fillers is uniform, the pressing load when the filler-containing film is pressure-bonded to the article is uniformly applied to the filler. Therefore, in the film sticking body in which the filler-containing film is pressure-bonded to the article and bonded, quality uniformity such as optical characteristics and mechanical characteristics can be ensured. Moreover, when an anisotropic conductive film is used as the filler-containing film, the state of trapping the conductive particles at the terminal becomes good during anisotropic conductive connection, and the conduction stability is improved.

As for the embedding rate (Lb / D), 10 or more areas having an area of 30 mm ² or more are arbitrarily extracted from the filler-containing film, a part of the film cross section is observed with an SEM image, and a total of 50 or more fillers are measured. Can be obtained. In order to increase accuracy, 200 or more fillers may be measured and obtained.

Further, the measurement of the embedding rate (Lb / D) can be obtained collectively for a certain number by adjusting the focus in the surface field image. Alternatively, a laser discriminating displacement sensor (manufactured by Keyence etc.) may be used for measuring the embedding rate (Lb / D).

(Aspects with an embedding rate of 60% or more and less than 100%)
As a more specific embedding mode of the filler 1 with an embedding rate (Lb / D) of 60% or more and 105% or less, first, the filler 1 is formed from the resin layer 2 as in the filler-containing film 10A shown in FIG. A mode of embedding at an embedding rate of 60% or more and less than 100% so as to be exposed can be given. The filler-containing film 10A has a portion of the surface of the resin layer 2 in contact with the filler 1 exposed from the resin layer 2 and the vicinity thereof in contact with the surface 2a of the resin layer at the center between adjacent fillers. It has a dent 2b that is recessed in a bowl shape with respect to the plane 2p.

When the filler-containing film 10A having the dent 2b is manufactured by pressing the filler 1 into the resin layer 2, the lower limit of the viscosity of the resin layer 2 when the filler 1 is pressed is preferably 3000 Pa · s or more. It is 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 15000 Pa · s or less, and further preferably 10,000 Pa · s or less. Further, such a viscosity is preferably obtained at 40 to 80 ° C., more preferably 50 to 60 ° C.

(Aspect with 100% embedding rate)
Next, among the filler-containing films of the present invention, as an embodiment with an embedding rate (Lb / D) of 100%, the filler shown in FIG. 1B around the filler 1 like the filler-containing film 10B shown in FIG. The filler-containing film 10C shown in FIG. 3A has a mortar-like dent 2b similar to the containing film 10A, and the exposed diameter Lc of the filler 1 exposed from the resin layer 2 is smaller than the particle diameter D of the filler 1. As shown in FIG. 4, a recess 2b around the exposed portion of the filler 1 suddenly appears in the vicinity of the filler 1, and the exposed diameter Lc of the filler 1 and the particle diameter D of the filler are substantially equal. The filler-containing film 10D shown in FIG. As described above, the surface of the resin layer 2 has a shallow dent 2c, and the filler 1 is exposed from the resin layer 2 at one point of the top 1a.

Note that a minute protruding portion 2q may be formed adjacent to the recess 2b of the resin layer 2 around the exposed portion of the filler or the recess 2c of the resin layer immediately above the filler. An example of this is shown in FIG. 3B.

Since these filler-containing films 10B, 10C, 10C ', and 10D have an embedding rate of 100%, the top portion 1a of the filler 1 and the surface 2a of the resin layer 2 are flush with each other. When the top portion 1a of the filler 1 and the surface 2a of the resin layer 2 are flush with each other, the filler-containing film and the article are compared to the case where the filler 1 protrudes from the resin layer 2 as shown in FIG. The amount of resin in the film thickness direction is less likely to be nonuniform in the periphery of each filler during pressure bonding, and there is an effect that the movement of the filler due to resin flow can be reduced. Even if the embedding rate is not strictly 100%, this effect can be obtained if the top of the filler 1 embedded in the resin layer 2 and the surface of the resin layer 2 are aligned with each other. it can. In other words, when the embedding rate (Lb / D) is approximately 80 to 105%, particularly 90 to 100%, the top of the filler 1 embedded in the resin layer 2 and the surface of the resin layer 2 are flush with each other. Therefore, the movement of the filler due to the resin flow can be reduced.

Among these filler-containing films 10B, 10C, and 10D, 10D can hardly eliminate the amount of resin around the filler 1 so that the movement of the filler due to resin flow can be eliminated. Since the filler 1 is exposed from the layer 2, the trapping property of the filler 1 in the article is also good. Therefore, when the filler-containing film is formed of an anisotropic conductive film, an effect that slight movement hardly occurs in the conductive particles captured by the terminal at the time of anisotropic conductive connection can be expected. Therefore, this aspect is particularly effective for anisotropic conductive films used for applications where the fine pitch and the space between bumps are narrow.

Note that the filler-containing films 10B (FIG. 2), 10C (FIG. 3A), and 10D (FIG. 4) having different shapes and depths of the recesses 2b and 2c are formed on the resin layer 2 when the filler 1 is pushed in, as will be described later. It can be produced by changing the viscosity, indentation speed or temperature.

(Mode of embedding rate over 100%)
Among the filler-containing films of the present invention, as an aspect exceeding 100% embedding rate, the filler 1 is exposed like the filler-containing film 10E shown in FIG. 5, and the tangential plane 2p is formed on the resin layer 2 around the exposed portion. The filler 1 is not exposed from the resin layer 2 (that is, the exposed diameter Lc = 0) as in the filler-containing film 10F shown in FIG. 6, and the surface of the resin layer 2 immediately above the filler 1 is present. The thing with the dent 2c with respect to the tangent plane 2p can be mention | raise | lifted.

In addition, the filler-containing film 10E (FIG. 5) which has the dent 2b in the resin layer 2 around the exposed part of the filler 1 and the filler-containing film 10F (FIG. 6) which has the dent 2c in the resin layer 2 immediately above the filler 1 are It can manufacture by changing the viscosity of the resin layer 2 at the time of indentation of the filler 1 at the time of manufacturing them, indentation speed, or temperature.

When the filler-containing film 10E shown in FIG. 5 is pressure-bonded to the article, the filler 1 is directly pressed from the article, so that the article and the filler can be easily joined. The trapping property of the conductive particles at the terminal when the electronic component is anisotropically conductively connected with the anisotropic conductive film is improved. In addition, when the filler-containing film 10F shown in FIG. 6 is pressure-bonded to the article, the filler 1 does not directly press the article and presses through the resin layer 2, but the amount of resin present in the pressing direction is small. Compared to the state of FIG. 8 (that is, the filler 1 is embedded with an embedding rate exceeding 100%, the filler 1 is not exposed from the resin layer 2 and the surface of the resin layer 2 is flat). For this reason, it is easy to apply a pressing force to the filler, and it is prevented that the filler 1 moves unnecessarily due to the resin flow at the time of pressure bonding with the article.

The recess 2b (FIGS. 1B, 2, 3A, 3B, and 5) of the resin layer 2 around the exposed portion of the filler and the recess 2c (FIGS. 4 and 6) of the resin layer immediately above the filler. From the viewpoint of facilitating the effect, the ratio (Le / D) of the maximum depth Le of the recess 2b around the exposed portion of the filler 1 and the particle diameter D of the filler 1 is preferably less than 50%, more preferably less than 30%. More preferably, it is 20 to 25%, and the ratio (Ld / D) of the maximum diameter Ld of the dent 2b around the exposed portion of the filler 1 to the particle diameter D of the filler 1 is preferably 100% or more, more preferably Is 100 to 150%, and the ratio (Lf / D) of the maximum depth Lf of the recess 2c to the particle diameter D of the filler 1 in the resin immediately above the filler 1 is greater than 0, preferably less than 10%, more Preferably it is 5% or less.

Note that the exposed diameter Lc of the filler 1 can be made equal to or less than the particle diameter D of the filler 1, and is preferably 10 to 90% of the particle diameter D. As shown in FIG. 4, it may be exposed at one point on the top of the filler 1, or the filler 1 may be completely buried in the resin layer 2 and the exposed diameter Lc may be zero.

On the other hand, the top of the filler 1 embedded in the resin layer 2 and the surface of the resin layer 2 are substantially flush with each other, and the depths of the recesses 2b and 2c (recesses from the tangential plane at the center between adjacent fillers). If there is a region where the filler with the deepest part) having a particle size of 10% or more of the particle diameter (hereinafter simply referred to as “filler having a recess depth of 10% or more flush with the resin layer”) is contained in the filler, Even if there is no problem in the performance and quality of the film, the appearance may be impaired. Further, when the filler-containing film and the article are bonded together with the dents 2b and 2c in such a region facing the article, the dents 2b and 2c may cause floating or the like after the bonding. For example, in the case where the filler-containing film is an anisotropic conductive film, if conductive particles having a dent depth of 10% or more flush with the insulating resin layer 2 are concentrated on one bump, it floats after connection with the bump. May occur and conductivity may be reduced. Therefore, in an area within 200 times the particle diameter of the filler from an arbitrary filler having a depth of 10% or more that is flush with the resin layer 2, the depth of the depression is 10 flush with the resin layer with respect to the total number of fillers. % Of the number of fillers is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. On the other hand, in a region where this ratio exceeds 50%, it is preferable to make the recesses 2b and 2c shallow by spraying a resin on the surface of the filler-containing film. In this case, it is preferable that the resin to be sprayed has a lower viscosity than the resin forming the resin layer 2, and the concentration of the resin to be sprayed is diluted to such an extent that the dent of the resin layer 2 can be confirmed after the spraying. It is desirable. Thus, by making the dents 2b and 2c shallow, the above-described appearance and floating problems can be improved.

In addition, as shown in FIG. 7, in the filler-containing film 10G having an embedding rate (Lb / D) of less than 60%, the filler 1 is likely to roll on the resin layer 2. From the viewpoint of improving the capture rate, it is preferable to set the embedding rate (Lb / D) to 60% or more.

Further, in an embodiment where the embedding rate (Lb / D) exceeds 100%, a resin interposed between the filler 1 and the article when the surface of the resin layer 2 is flat like the filler-containing film 10X shown in FIG. The amount is excessive. Further, when the surface of the resin layer 2 is raised along the shape of the filler 1 as in the filler-containing film 10Y shown in FIG. 9, the filler 1 is caused to flow by the resin flow of the resin layer 2 at the time of pressure bonding with the article. easy. Furthermore, since the filler 1 presses the article through the resin without directly contacting the article and pressing the article, the filler is easily flowed by the resin flow.

In the present invention, the presence of the dents 2b and 2c on the surface of the resin layer 2 can be confirmed by observing the cross section of the filler-containing film with a scanning electron microscope, and can also be confirmed with surface field observation. The dents 2b and 2c can be observed even with an optical microscope or a metal microscope. The size of the recesses 2b and 2c can also be confirmed by focus adjustment during image observation. The same is true even after the resin is sprayed on the deep dents as described above.

<Deformation aspect of a filler containing film>
(Second insulating resin layer)
The filler-containing film of the present invention preferably has the lowest melting than the resin layer 2 on the surface of the filler dispersion layer 3 where the dents 2b of the resin layer 2 are formed, as in the filler-containing film 10H shown in FIG. You may laminate | stack the 2nd resin layer 4 with a low viscosity. The second resin layer and the third resin layer described later are layers that do not contain the filler 1 dispersed in the filler dispersion layer. Further, like the filler-containing film 10I shown in FIG. 11, the resin layer is formed on the surface of the filler dispersion layer 3 where the recess 2b of the resin layer 2 is not formed (the surface opposite to the surface where the recess is formed). A second resin layer 4 having a minimum melt viscosity lower than 2 may be laminated.

The second resin layer 4 can also be made insulating or conductive depending on the use of the filler-containing film. When the filler-containing film and the article are pressure-bonded by laminating the second resin layer 4, even if the article has irregularities, the second resin layer can fill the space formed by the irregularities. it can. Accordingly, when the filler-containing film is an anisotropic conductive film having an insulating resin layer as the second resin layer, the opposite electronic parts are anisotropically conductively connected using the anisotropic conductive film. Sometimes, the space formed by the electrodes and bumps of the electronic components can be filled with the second resin layer, and the adhesion between the electronic components can be improved.

In the case where the opposite electronic parts are anisotropically conductively connected using the anisotropic conductive film having the second resin layer 4, whether or not the second resin layer 4 is on the formation surface of the recess 2b. Regardless, it is preferable that the second resin layer 4 is on the first electronic component side such as an IC chip (in other words, the resin layer 2 is on the second electronic component side such as a substrate). By doing so, unintentional movement of the conductive particles can be avoided, and the trapping property can be improved. Usually, the first electronic component such as an IC chip is on the pressing jig side, the second electronic component such as a substrate is on the stage side, and the anisotropic conductive film is temporarily bonded to the second electronic component, and then the first electronic component is The component and the second electronic component are finally crimped. Depending on the size or the like of the crimping region of the second electronic component, the first electronic component and the second electronic component are temporarily attached after the anisotropic conductive film is temporarily attached to the first electronic component. Is crimped.

The minimum melt viscosity between the resin layer 2 and the second resin layer 4 is more likely to be filled with the second resin layer in the space formed by the surface irregularities of the article to be thermocompression-bonded with the filler-containing film. For this reason, when the adhesiveness between the filler-containing film and the article, or when the opposing article is thermocompression bonded via the filler-containing film, the adhesiveness between the opposing articles is improved. Further, as the difference is increased, the amount of movement of the resin layer 2 existing in the filler dispersion layer 3 becomes relatively small with respect to the second resin layer 4, and the unnecessary flow of the filler held in the resin layer 2 is reduced. Can be reduced. Therefore, when the filler-containing film is an anisotropic conductive film having an insulating second resin layer, it is formed by electrodes and bumps of electronic parts that are anisotropically conductively connected by the anisotropic conductive film. The space to be filled is easily filled with the second resin layer 4, and the effect of improving the adhesion between the electronic components can be expected. In addition, since the amount of movement of the resin layer 2 holding the conductive particles in the filler dispersion layer 3 is relatively small with respect to the second resin layer, the trapping property of the conductive particles at the terminal is easily improved.

Although the minimum melt viscosity ratio between the resin layer 2 and the second resin layer 4 depends on the ratio of the layer thicknesses of the resin layer 2 and the second resin layer 4, it is preferably 2 or more in practice, more preferably 5 or more, more preferably 8 or more. On the other hand, if this ratio is too large, when a long filler-containing film is used as a wound body, there is a possibility that the resin protrudes or blocks, so that the resin layer 2 and the second resin layer 4 are practically used. The minimum melt viscosity ratio is preferably 15 or less. The preferable minimum melt viscosity of the second resin layer 4 more specifically satisfies the above-mentioned ratio and is 3000 Pa · s or less, more preferably 2000 Pa · s or less, and particularly 100 to 2000 Pa · s.

The second resin layer 4 can be formed by adjusting the viscosity in the same resin composition as the resin layer 2.

Further, the thickness of the second resin layer 4 can be appropriately set according to the use of the filler-containing film. From the viewpoint of not excessively increasing the difficulty of the lamination process of the second resin layer 4, it is generally preferable that the particle diameter of the filler is 0.2 to 50 times. When the filler-containing film is an anisotropic conductive film 10H or 10I, the layer thickness of the second resin layer 4 is preferably 4 to 20 μm, and the conductive particle diameter is preferably 1 to 8 times.

In the anisotropic conductive films 10H and 10I, the minimum melt viscosity of the entire anisotropic conductive film including the insulating resin layer 2 and the second resin layer 4 is the resin layer 2 and the second resin layer. Although it depends on the thickness ratio of 4, it may be 8000 Pa · s or less for practical use, and may be 200 to 7000 Pa · s for easy filling between the bumps, preferably 200 to 4000 Pa. -S.

(Third resin layer)
A third resin layer may be provided on the opposite side across the second resin layer 4 and the resin layer 2. The third resin layer can also be made insulating or conductive depending on the use of the filler-containing film. For example, when the filler-containing film is an anisotropic conductive film having an insulating third resin layer, the third resin layer can function as a tack layer. Similar to the second resin layer, the third resin layer may be provided to fill a space formed by the electrodes and bumps of the electronic component.

The resin composition, viscosity, and thickness of the third resin layer may be the same as or different from those of the second resin layer. The minimum melt viscosity of the filler-containing film in which the resin layer 2, the second resin layer 4, and the third resin layer are combined is not particularly limited, but may be 8000 Pa · s or less, or 200 to 7000 Pa · s. It may be 200 to 4000 Pa · s.

(Other lamination modes)
Depending on the use of the filler-containing film, a filler dispersion layer may be laminated, and a layer containing no filler, such as the second resin layer, may be interposed between the laminated filler dispersion layers. A second resin layer or a third resin layer may be provided on the outer layer.

<Method for producing filler-containing film>
The method for producing a filler-containing film of the present invention includes a step of forming a filler dispersion layer in which a filler is dispersed in a resin layer. The step of forming the filler dispersion layer includes a step of holding the filler in a state where the filler is dispersed on the surface of the resin layer, and a step of pushing the filler held in the resin layer into the resin layer.

Among these, in the step of pushing the filler into the resin layer, the resin layer when the filler is pushed so that the surface of the resin layer near the filler has a dent with respect to the tangent plane of the resin layer at the center between the adjacent fillers Adjust the viscosity, indentation speed or temperature.

The resin layer into which the filler is pushed is not particularly limited as long as the depressions 2b and 2c of the previous operation can be formed, but it is preferable that the minimum melt viscosity is 1100 Pa · s or more and the viscosity at 60 ° C. is 3000 Pa · s or more. Among them, the minimum melt viscosity is preferably 1500 Pa · s or more, more preferably 2000 Pa · s or more, further preferably 3000 to 15000 Pa · s, and particularly preferably 3000 to 10,000 Pa · s. Preferably it is 3000 Pa · s or more, more preferably 4000 Pa · s or more, further preferably 4500 Pa · s or more, and the upper limit is preferably 20000 Pa · s or less, more preferably 15000 Pa · s or less, further preferably 10000 Pa · s or less. It is. Therefore, it is preferable that the minimum melt viscosity of the resin layer that holds the filler on the surface is in the above range.

When the filler-containing film is formed from a single layer of the filler dispersion layer 3, the filler-containing film of the present invention, for example, holds the filler 1 on the surface of the resin layer 2 in a predetermined arrangement, and the filler 1 is a flat plate or It is manufactured by pushing into the resin layer with a roller. In the case of producing a filler-containing film having an embedding rate of more than 100%, the film may be pressed with a pressing plate having a convex portion corresponding to the filler arrangement.

Here, the embedding amount of the filler 1 in the resin layer 2 can be adjusted by the pressing force, temperature, etc. when the filler 1 is pushed, and the shapes and depths of the recesses 2b, 2c are the resin when pushing. It can adjust with the viscosity of the layer 2, indentation speed, temperature, etc. For example, when the anisotropic conductive film 10B (FIG. 2) is manufactured as the filler-containing film, the viscosity of the insulating resin layer 2 when the conductive particles 1 are pushed in is preferably 8000 Pa · s (60 ° C.). When the isotropic conductive film 10C (FIG. 3A) is manufactured, the viscosity of the insulating resin layer 2 when the conductive particles 1 are pushed in is preferably 12000 Pa · s (70 ° C.), and the anisotropic conductive film 10D (FIG. 4), when manufacturing the anisotropic conductive film 10E (FIG. 5), it is preferable that the viscosity of the insulating resin layer 2 when the conductive particles 1 are pushed in is 4500 Pa · s (60 ° C.). The viscosity of the insulating resin layer 2 when the conductive particles 1 are pushed in is preferably 7000 Pa · s (70 ° C.). When the anisotropic conductive film 10F (FIG. 6) is manufactured, the conductive particles 1 It is preferable that the viscosity of the insulating resin layer 2 at the time included the 3500Pa · s (70 ℃).

Further, as a method for holding the filler 1 in the resin layer 2, a known method can be used. For example, the filler 1 can be directly sprayed on the resin layer 2, or the filler 1 can be attached as a single layer to a film that can be biaxially stretched, the film is biaxially stretched, and the resin layer 2 is applied to the stretched film. By pressing and transferring the filler to the resin layer 2, the filler 1 is held on the resin layer 2. Alternatively, the filler 1 can be held on the resin layer 2 using a transfer mold.

When the transfer layer is used to hold the filler 1 on the resin layer 2, examples of the transfer mold include inorganic materials such as silicon, various ceramics, glass, and stainless steel, and organic materials such as various resins. On the other hand, those in which openings are formed by a known opening forming method such as a photolithographic method or those in which a printing method is applied can be used. Further, the transfer mold can take a plate shape, a roll shape or the like. The present invention is not limited by the above method.

Further, the second resin layer 4 having a lower viscosity than that of the resin layer 2 can be laminated on the surface of the resin layer 2 into which the filler has been pressed in, or on the opposite surface thereof.

When a filler-containing film is pressure-bonded to an article, or when an opposite article is pressure-bonded using a filler-containing film, the filler-containing film must be somewhat long in order to economically perform the pressure-bonding. preferable. Therefore, the length of the filler-containing film is preferably 5 m or more, more preferably 10 m or more, and even more preferably 25 m or more. On the other hand, if the filler-containing film is excessively long, the conventional connection device cannot be used when the filler-containing film is pressure-bonded to the article, and the handleability is also poor. Therefore, the length of the filler-containing film is preferably 5000 m or less, more preferably 1000 m or less, and even more preferably 500 m or less. Such a long body of the filler-containing film is preferably a wound body wound around a core from the viewpoint of excellent handleability.

<Usage method of filler-containing film>
The filler-containing film of the present invention can be used by being attached to an article in the same manner as a conventional filler-containing film, and the article is not particularly limited as long as the filler-containing film can be attached. It can be attached to various articles according to the use of the filler-containing film by pressure bonding, preferably by heat pressure bonding. At the time of bonding, light irradiation may be used, and heat and light may be used in combination. For example, when the resin layer of the filler-containing film has sufficient adhesiveness to the article to which the filler-containing film is bonded, the filler-containing film is a single article by lightly pressing the resin layer of the filler-containing film against the article. The film sticking body stuck on the surface can be obtained. In this case, the surface of the article is not limited to a flat surface, and may be uneven, or may be bent as a whole. When the article is in the form of a film or a flat plate, the filler-containing film may be bonded to the article using a pressure roller. Thereby, the filler of a filler containing film and articles | goods can also be joined directly.

In addition, a filler-containing film is interposed between the first article and the second article facing each other, the two articles facing each other are joined by a thermocompression roller or a crimping tool, and the filler is sandwiched between the articles. Good. Further, the filler-containing film may be sandwiched between the articles so that the filler and the article are not in direct contact with each other.

In particular, when the filler-containing film is an anisotropic conductive film, using a thermocompression bonding tool, a first electronic component such as an IC chip, an IC module, or an FPC, an FPC, a glass substrate through the anisotropic conductive film It can be preferably used for anisotropic conductive connection with a second electronic component such as a plastic substrate, a rigid substrate, or a ceramic substrate. IC chips and wafers may be stacked using an anisotropic conductive film to form a multilayer. In addition, the electronic component connected with the anisotropic conductive film of this invention is not limited to the above-mentioned electronic component. It can be used for various electronic parts that have been diversified in recent years.

Therefore, this invention includes the manufacturing method of the bonding body which bonded the filler containing film of this invention to various articles | goods by crimping, and a bonding body. In particular, when the filler-containing film is an anisotropic conductive film, a method for manufacturing a connection structure for anisotropic conductive connection between electronic components using the anisotropic conductive film, and a connection obtained thereby A structure, that is, a connection structure in which electronic components are anisotropically conductively connected by the anisotropic conductive film of the present invention is also included.

As a method for connecting an electronic component using an anisotropic conductive film, when the anisotropic conductive film is composed of a single layer of the conductive particle dispersion layer 3, the anisotropic conductive film is used for second electronic components such as various substrates. The first electronic component such as an IC chip on the side where the conductive particles 1 of the anisotropic conductive film temporarily bonded and temporarily bonded from the side where the conductive particles 1 are embedded in the surface is not embedded in the surface. And can be manufactured by thermocompression bonding. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerizable compound, but also a photopolymerization initiator and a photopolymerizable compound (may be the same as the thermal polymerizable compound), A pressure bonding method using both light and heat may be used. In this way, unintentional movement of the conductive particles can be minimized. Further, the side on which the conductive particles are not embedded may be temporarily attached to the second electronic component for use. Note that the anisotropic conductive film may be temporarily attached to the first electronic component instead of the second electronic component.

Further, when the anisotropic conductive film is formed of a laminate of the conductive particle dispersion layer 3 and the second insulating resin layer 4, the conductive particle dispersion layer 3 is temporarily attached to a second electronic component such as various substrates. Then, the first electronic component such as an IC chip is aligned and placed on the second insulating resin layer 4 side of the anisotropic conductive film that has been temporarily pressure-bonded, and thermocompression-bonded. The second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component. Alternatively, the conductive particle dispersion layer 3 side can be temporarily attached to the first electronic component for use.

Hereinafter, the anisotropic conductive film which is one aspect of the filler-containing film of the present invention will be specifically described with reference to examples.
Examples 1 to 15 and Comparative Examples 1 to 3
(1) Manufacture of anisotropic conductive film Resin compositions for forming an insulating resin layer, a second insulating resin layer, and a tack layer were prepared using the formulations shown in Tables 1A and 1B.

The resin composition for forming the insulating resin layer is coated on a PET film having a film thickness of 50 μm with a bar coater, dried in an oven at 80 ° C. for 5 minutes, and the thicknesses shown in Tables 2A and 2B on the PET film. The insulating resin layer was formed. Similarly, a second insulating resin layer and a tack layer were formed on the PET film with the thicknesses shown in Table 2A and Table 2B, respectively.

However, in Comparative Example 3, conductive particles were mixed with the resin composition forming the insulating resin layer to form an insulating resin layer (number density 70000 / mm ² ) in which the conductive particles were dispersed in a single layer at random.

On the other hand, the mold is prepared so that the conductive particles 1 have a square lattice arrangement shown in FIG. 1A in plan view, the interparticle distance is equal to the particle diameter of the conductive particles, and the number density of the conductive particles is 28000 / mm ^2. did. That is, the convex pattern of the mold is a square lattice arrangement, and the pitch of the convex portions on the lattice axis is twice the average conductive particle diameter (3 μm), which is formed by the lattice axis and the short direction of the anisotropic conductive film. A mold having an angle θ of 15 ° is manufactured, and a known transparent resin pellet is poured into the mold in a melted state, cooled, and solidified, whereby the resin mold having the array pattern shown in FIG. 1A is formed. Formed.

As conductive particles, metal-coated resin particles (Sekisui Chemical Co., Ltd., AUL703, average particle diameter of 3 μm) are coated with insulating fine particles (average particle diameter of 0.3 μm) according to the description in JP-A No. 2014-132567. The conductive particles were filled in resin-type dents, and the above-mentioned insulating resin layer was covered thereon and adhered by pressing at 60 ° C. and 0.5 MPa. Then, the insulating resin layer is peeled from the mold, and the conductive particles on the insulating resin layer are pressed into the insulating resin layer by pressing (pressing conditions: 60 to 70 ° C., 0.5 Mpa) to disperse the conductive particles. An anisotropic conductive film composed of a single layer was produced (Examples 6 to 10, 14 and Comparative Example 2). The embedded state of the conductive particles was controlled by the indentation conditions.

Further, a two-layer type anisotropic conductive film was prepared by laminating the second insulating resin layer on the conductive particle dispersion layer prepared in the same manner (Examples 1 to 5, 11 to 13, Comparative Example 1). ). In Comparative Example 3, the second insulating resin layer was laminated on the insulating resin layer in which the conductive particles were dispersed as described above. In this case, as shown in Table 2, the surface of the conductive particle dispersion layer on which the second insulating resin layer was laminated was the surface of the insulating resin layer into which the conductive particles were pressed, or the surface on the opposite side.

Further, a three-layer type anisotropic conductive film was prepared by laminating a tack layer on a similarly prepared two-layer type anisotropic conductive film (Example 15).

(2) Embedding State The anisotropic conductive films of Examples 1 to 15 and Comparative Examples 1 to 3 were cut along a cutting line passing through the conductive particles, and the cross section was observed with a metal microscope. In Examples 4 to 10, 14 and Comparative Example 2 where the conductive particles are exposed on the surface of the anisotropic conductive film or the conductive particles are in the vicinity of the film surface of the anisotropic conductive film, the film surface is made of metal. Observed with a microscope. 12A shows a cross-sectional photograph of Example 2, FIG. 12B shows a cross-sectional photograph of Example 3, FIG. 12C shows a cross-sectional photograph of Comparative Example 3, FIG. 13A shows a top view of Example 4, and FIG. 13B shows a top view of Example 8. Show photos.

In Examples 1 to 7, 9 to 15, and Comparative Example 1, conductive particles having an embedding rate of less than 60% and conductive particles having an embedding rate of more than 100% were exposed from the insulating resin layer. In Examples 1 to 7 and 9 to 15, dents 2b were observed on the surface of the insulating resin layer around the electroparticles (FIGS. 12A, 12B, and 13A). In Comparative Example 3, the embedding rate was less than 100%, but the conductive particles were not exposed from the insulating resin layer, and the recesses 2b and 2c were not observed. In the photographs of FIGS. 12A, 12B, and 12C, the metal layer 1p of the conductive particles 1 appears in a dark circle, and the insulating particle layer 1q attached to the metal layer 1p appears in a light color.

In Example 8, the conductive particles are completely embedded in the insulating resin layer, and the conductive particles are not exposed from the insulating resin layer, but a dent 2c is observed on the surface of the insulating resin layer immediately above the conductive particle layer. (FIG. 13B). In Comparative Example 2, the embedding rate was slightly larger than 100%, and the conductive particles were not exposed from the resin layer, but the surface of the resin layer was flat and no dent was observed on the surface of the resin layer immediately above the conductive particles. .

(3) Evaluation For the anisotropic conductive films of Examples and Comparative Examples prepared in (1), (a) initial conduction resistance, (b) conduction reliability, (c) particle trapping property, (D) The positional deviation was measured or evaluated. The results are shown in Table 2A and Table 2B.

(A) Initial conduction resistance The anisotropic conductive film of each Example and Comparative Example is cut with a sufficient area for connection, and sandwiched between an IC for evaluation of conduction characteristics and a glass substrate, and heated and pressurized (180 ° C. 60 MPa, 5 seconds) to obtain each evaluation connection, and the conduction resistance of the obtained evaluation connection was measured by a four-terminal method. The initial conduction resistance is practically preferably 2Ω or less, more preferably 0.6Ω or less.

Here, the IC for evaluation and the glass substrate correspond to their terminal patterns, and the sizes are as follows. Further, when connecting the evaluation IC and the glass substrate, the longitudinal direction of the anisotropic conductive film and the short direction of the bump were matched.

IC for evaluating conduction characteristics
Outline 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 made by Corning
Outline 30 × 50mm
Thickness 0.5mm
Electrode ITO wiring

(B) Conduction reliability The conduction resistance after placing the evaluation connection prepared in (a) in a thermostatic bath at a temperature of 85 ° C. and a humidity of 85% RH for 500 hours was measured in the same manner as the initial conduction resistance. The conduction reliability is practically preferably 6Ω or less, more preferably 4Ω or less.

(C) Particle trapping property Using an IC for particle trapping evaluation, this evaluation IC and the glass substrate (ITO wiring) corresponding to the terminal pattern are heated and pressurized (180 ° C., 60 MPa) while shifting the alignment by 6 μm. 5 seconds), the number of trapped conductive particles was measured for 100 of the 6 μm × 66.6 μm region where the bump of the IC for evaluation and the terminal of the substrate overlap, and the minimum number of traps was determined and evaluated according to the following criteria: . Practically, it is preferable that it is B evaluation or more.

IC for particle trapping evaluation
Outline 1.6 × 29.8mm
Thickness 0.3mm
Bump specifications Size 12 × 66.6μm, bump pitch 22μm (L / S = 12μm / 10μm), bump height 12μm

Particle trapping evaluation criteria A 5 or more B 3 or more and less than 5 C 3 or less

(D) Position shift Using the same evaluation IC as in (c), this evaluation IC and the glass substrate (ITO wiring) corresponding to the terminal pattern are aligned and heated and pressurized (180 ° C., 60 MPa, 5 seconds). In this case, the particle pitch before heating and pressurization and the particle pitch after heating and pressurization (measured from indentation observation from the glass side) are measured using a metal microscope, and the average of each is obtained. The gap was calculated and evaluated according to the following criteria. Practically, it is preferable that it is C evaluation or more.

In Comparative Example 3, since the conductive particles are randomly dispersed, the positional deviation is not evaluated.

Particle gap = 100 * P1 / P0
(Wherein, P1: average particle pitch after heating and pressurization,
P0: average particle pitch before heating and pressing)

Evaluation criteria for positional deviation A A Particle gap of 160% or less B Particle gap of over 160% 180% or less C Particle gap of over 180% 200% or less D Particle gap of over 200%

From Table 2A and Table 2B, Examples 1 to 3 in which the embedding rate of the conductive particles is between 60% and 105%, the conductive particles protrude from the insulating resin layer, and have the dent 2b, and the conductive particles are insulating. Example 8 completely embedded in the resin layer and having the recess 2c has sufficiently low initial conduction resistance and conduction reliability, and evaluation of particle trapping property and positional deviation is good, but the embedding rate is in this range. In Comparative Example 1 in which the conductive particles protrude from the insulating resin layer and there is no dent 2b, and in Comparative Example 2 in which the conductive particles are completely embedded in the insulating resin layer and there is no dent 2c, the positional deviation is D evaluation. It can be seen that sometimes the conductive particles cannot be held, and the fine pitch connection cannot be supported. In addition, the conductive particles 1 are covered with the insulating resin layer 2 and protrude from the surface of the insulating resin layer 2 in the central portion between the adjacent conductive particles, but the recesses 2b and 2c are formed in the vicinity of the conductive particles 1. It can be seen that Comparative Example 3, which does not, has poor conduction reliability. Therefore, when the surface of the insulating resin layer 2 is raised along the shape of the conductive particles 1, the conductive particles are easily affected by the resin flow during anisotropic conductive connection, and the conductive particles are connected to the terminals of the conductive particles. It can be inferred that the indentation is insufficient.

In Examples 1 to 3 and 8 described above, the minimum melt viscosity of the insulating resin layer is 2000 Pa · s or more and the 60 ° C. melt viscosity is 3000 Pa · s or more. In Comparative Examples 1 and 2, the minimum melt viscosity is 1000 Pa. S, the melt viscosity at 60 ° C. is 1500 Pa · s, and it can be seen that the depressions 2b and 2c were not formed because the viscosity at the time of indentation was lowered by adjusting the indentation conditions of the conductive particles. On the other hand, in Comparative Example 3, the minimum melt viscosity and the viscosity at 60 ° C. are the same as those in Examples 1 to 3, but the conductive particle dispersion layer was not formed by pushing the conductive particles into the insulating resin layer. The conductive particles are dispersed in the resin composition for forming the conductive resin layer and coated to form the conductive particle dispersed layer, so that the recesses 2b and 2c are not formed.

Further, in contrast to Example 3 (minimum melt viscosity 6000 Pa · s, 60 ° C. melt viscosity 8000 Pa · s), these are as low as Example 11 (minimum melt viscosity 2000 Pa · s, 60 ° C. melt viscosity 3000 Pa · s). However, even if it is high as in Example 12 (minimum melt viscosity of 10000 Pa · s, 60 ° C. melt viscosity of 15000 Pa · s), when the dent 2b is formed around the conductive particles, the positional deviation is more than B evaluation. It turns out that there is no problem in practical use.

Furthermore, in Examples 1 to 3 and 8 described above, the embedding rate of the conductive particles is between 60 to 105%, but in comparison with this, Example 13 having an embedding rate of less than 60% is evaluated for positional deviation. It turns out that becomes low.

From Examples 4 and 5 and Examples 6 and 7, when the anisotropic conductive film is a two-layer type of a conductive particle dispersion layer and a second insulating resin layer, or a single layer of a conductive particle dispersion layer It can also be seen that the evaluation of particle trapping property and positional deviation is practically good. Moreover, from Examples 2, 3, 13 and Example 15, it is found that the particle trapping property is practically good even when a two-layer type anisotropic conductive film is further provided with a tack layer to form a three-layer type.

From Example 3 and Examples 4 and 5, when the anisotropic conductive film is a two-layer type of the conductive particle dispersion layer and the second insulating resin layer, on the surface into which the conductive particles of the insulating resin layer are pressed. It can be seen that evaluation of particle trapping property and positional deviation is practically good both when the second insulating resin layer is laminated and when the second insulating resin layer is laminated on the opposite side.

Furthermore, from Examples 6, 7, 9, 10 and Example 14, when the ratio La / D between the layer thickness La of the insulating resin layer and the particle diameter D of the conductive particles exceeds 10 with respect to 10 or less, the positional deviation It turns out that evaluation becomes low.

In addition, when the same resin composition diluted on the surface where the conductive particles of the anisotropic conductive films of Examples 4 and 5 are exposed is sprayed and the surface thereof is substantially smoothed, the same evaluation is performed. As a result, almost equivalent results were obtained.

In addition, the number of shorts in 100 bumps is set for the connection for evaluation of the initial conduction resistance of all the examples in the same manner as the method for measuring the number of shorts described in the examples of Japanese Patent Application Laid-Open No. 2016-059883. I confirmed that there was no short circuit. Further, when the short-circuit occurrence rates were determined for the anisotropic conductive films of all the examples according to the measurement method of the short-circuit occurrence rate described in the examples of JP-A-2016-059882, all were less than 50 ppm. It was confirmed that there was no problem in practical use.

Experimental Examples 1-4
(Preparation of anisotropic conductive film)
In order to investigate the influence of the resin composition of the insulating resin layer on the film forming ability and the conduction characteristics of the anisotropic conductive film used for the COG connection, the insulating resin layer and the second insulating property are blended as shown in Table 3. A resin composition for forming a resin layer was prepared. In this case, the minimum melt viscosity of the resin composition was adjusted according to the resin composition preparation conditions. Using the obtained resin composition, an insulating resin layer is formed in the same manner as in Example 1, and the conductive particles are pressed into the insulating resin layer to form an anisotropic layer composed of a single layer of the conductive particle dispersion layer. A conductive film was prepared, and a second insulating resin layer was laminated on the side where the conductive particles of the insulating resin layer were pushed, to prepare an anisotropic conductive film shown in Table 4. In this case, the arrangement of the conductive particles is the same as in Example 1. Further, the conductive particles were brought into the embedded state shown in Table 4 by appropriately adjusting the indentation conditions of the conductive particles.

In this anisotropic conductive film production process, the film shape was not maintained in Experimental Example 4 after the conductive particles were pushed into the insulating resin layer (film shape evaluation: NG), but in the other experimental examples, the film shape was not maintained. Was maintained (film shape evaluation: OK). Therefore, the embedded state of the conductive particles in the anisotropic conductive films of the experimental examples except experimental example 4 was observed and measured with a metal microscope, and further evaluation was performed.

In each experimental example except experimental example 4, a dent around the conductive particles exposed from the insulating resin layer, a dent in the insulating resin layer immediately above the conductive particles, or both of these were observed. Table 4 shows the measured values of the dents most clearly observed for each experimental example. The observed embedded state satisfied the above-described preferable range.

(Evaluation)
(A) Initial conduction resistance and conduction reliability The initial conduction resistance and conduction reliability were evaluated in the same manner as in Example 1. The evaluation criteria in this case are as follows. The results are shown in Table 4.

Evaluation criteria for initial conduction resistance OK: 2.0Ω or less NG: Greater than 2.0Ω

Evaluation standard of conduction reliability OK: 6.0Ω or less NG: Greater than 6.0Ω

(B) Particle trapping property The particle trapping property was evaluated in the same manner as in Example 1.
As a result, all of Experimental Examples 1 to 3 were B judgment or higher.

(C) Short-circuit occurrence rate The short-circuit occurrence rate was evaluated in the same manner as in Example 1.
As a result, it was confirmed that all of Experimental Examples 1 to 3 were less than 50 ppm and there was no practical problem.

From Table 4, it can be seen that when the minimum melt viscosity of the insulating resin layer is 800 Pa · s, it is difficult to form a film having a dent in the insulating resin layer near the conductive particles. On the other hand, when the minimum melt viscosity of the insulating resin layer is 1500 Pa · s or more, a depression can be formed on the surface of the insulating resin layer in the vicinity of the conductive particles by adjusting the conditions when the conductive particles are embedded, thus obtained. It can be seen that the anisotropic conductive film has good conduction characteristics for COG. In all of Experimental Examples 1 to 3, the initial conduction resistance was 0.6Ω or less, and the conduction reliability was 4Ω or less, indicating good results.

Experimental Examples 5-8
(Preparation of anisotropic conductive film)
In order to investigate the influence of the resin composition of the insulating resin layer on the film forming ability and the conduction characteristics of the anisotropic conductive film used for FOG connection, the insulating resin layer and the second insulating property are blended as shown in Table 5 A resin composition for forming a resin layer was prepared. In this case, the conductive particles were arranged in a hexagonal lattice arrangement with a number density of 15000 / mm ² , and one of the lattice axes was inclined 15 ° with respect to the longitudinal direction of the anisotropic conductive film. Moreover, the minimum melt viscosity of the resin composition was adjusted according to the preparation conditions of the resin composition. Using the obtained resin composition, an insulating resin layer is formed in the same manner as in Example 1, and the conductive particles are pressed into the insulating resin layer to form an anisotropic layer composed of a single layer of the conductive particle dispersion layer. A conductive film was prepared, and a second insulating resin layer was laminated on the side where the conductive particles of the insulating resin layer were pressed, to prepare anisotropic conductive films shown in Table 6. In this case, the conductive particles were in the embedded state shown in Table 6 by appropriately adjusting the indentation conditions of the conductive particles.

In this anisotropic conductive film preparation process, the film shape was not maintained in Experimental Example 8 after the conductive particles were pushed into the insulating resin layer (film shape evaluation: NG), but in the other experimental examples, the film shape was not maintained. Was maintained (film shape evaluation: OK). Therefore, the embedded state of the conductive particles was observed and measured for the anisotropic conductive films of the experimental examples except experimental example 8, and further evaluation was performed.

In each experimental example except Experimental Example 8, a dent around the conductive particles exposed from the insulating resin layer, a dent in the insulating resin layer directly above the conductive particles, or both of these were observed. Table 6 shows the measured values of the dents most clearly observed for each experimental example. The observed embedded state satisfied the above-described preferable range.

(Evaluation)
(A) Initial conduction resistance and conduction reliability (i) Initial conduction resistance and (ii) conduction reliability were evaluated as follows. The results are shown in Table 6.

(I) Initial conduction resistance The anisotropic conductive film obtained in each experimental example was cut in an area sufficient for connection, and sandwiched between an FPC for evaluating conduction characteristics and a non-alkali glass substrate, and the tool width of the thermocompression bonding tool Heating and pressing were performed at 1.5 mm (180 ° C., 4.5 MPa, 5 seconds) to obtain each evaluation connection. The conduction resistance of the obtained connection for evaluation was measured by a four-terminal method, and the measured value was evaluated according to the following criteria.

FPC for evaluation of conduction characteristics:
Terminal pitch 20μm
Terminal width / inter-terminal space 8.5μm / 11.5μm
Polyimide film thickness (PI) / copper foil thickness (Cu) = 38/8, Sn plating

Non-alkali glass substrate:
Electrode ITO wiring thickness 0.7mm

Evaluation criteria for initial conduction resistance OK: Less than 2.0Ω NG: 2.0Ω or more

(Ii) Conduction reliability The connected object for evaluation produced in (i) is placed in a thermostatic bath at a temperature of 85 ° C. and a humidity of 85% RH for 500 hours, and the subsequent conduction resistance is measured in the same manner as the initial conduction resistance. Values were evaluated according to the following criteria.

Evaluation criteria of conduction reliability OK: Less than 5.0Ω NG: 5.0Ω or more (b) Particle trapping property The number of trapped conductive particles is measured for 100 terminals of the connection object for evaluation prepared in (i), and the minimum trapping is achieved. I asked for a number. If the minimum number of captures is 10 or more, there is no practical problem.
In all of Experimental Examples 5 to 7, the minimum number of captures was 10 or more.

(C) Short-circuit occurrence rate The number of shorts of the connection object for evaluation produced in (i) was measured, and the short-circuit occurrence rate was obtained from the measured number of shorts and the number of gaps of the connection object for evaluation. In all of Experimental Examples 5 to 7, the short-circuit occurrence rate was less than 50 ppm, and it was confirmed that there was no practical problem.

It can be seen from Table 6 that when the minimum melt viscosity of the insulating resin layer is 800 Pa · s, it is difficult to form a film having a dent on the surface of the insulating resin layer near the conductive particles. On the other hand, when the minimum melt viscosity of the insulating resin layer is 1500 Pa · s or more, a depression can be formed on the surface of the insulating resin layer in the vicinity of the conductive particles by adjusting the conditions when the conductive particles are embedded, thus obtained. It can be seen that the anisotropic conductive film has good conduction characteristics for FOG.

DESCRIPTION OF SYMBOLS 1 Filler, conductive particle 1a Filler top part 1p Metal layer of conductive particle 1q Insulating particle layer 2 Resin layer 2a Surface of resin layer 2b Recess 2c Recess 2p Tangent plane 2q Protruding part 3 Filler dispersion layer, conductive particle dispersion layer 4 Second resin Layer, second insulating resin layer 10A, 10B, 10C, 10C ', 10D, 10E, 10F, 10G, 10H, 10I Filler-containing film, anisotropic conductive film 20 Terminal A Grid axis D Filler particle diameter, conductivity Particle diameter of particle La Layer thickness of resin layer Lb Embedding amount (Distance of deepest part of filler from tangential plane in central part between adjacent fillers)
Lc Exposed diameter Ld Maximum diameter of the recess Le Maximum depth of the recess around the exposed portion of the filler Lf Maximum depth of the recess in the resin immediately above the filler θ Angle formed between the longitudinal direction of the terminal and the lattice axis of the conductive particle array

Claims

A filler-containing film having a filler dispersion layer in which a filler is dispersed in a resin layer,
A filler-containing film in which the surface of the resin layer in the vicinity of the filler has a dent with respect to the tangent plane of the resin layer at the center between adjacent fillers.
2. The filler-containing film according to claim 1, wherein a dent is formed on the surface of the resin layer around the filler exposed from the resin layer.
The filler-containing film according to claim 2, wherein the ratio (Le / D) of the depth Le of the dent from the tangent plane to the particle diameter D of the filler is less than 50%.
The filler-containing film according to claim 2 or 3, wherein a ratio (Ld / D) between the maximum diameter Ld of the dent and the particle diameter D of the filler is 100% or more.
2. The filler-containing film according to claim 1, wherein a dent is formed on the surface of the resin layer immediately above the filler buried in the resin layer without being exposed from the resin layer.
The filler-containing film according to claim 1, wherein the filler is in contact with the tangent plane of the resin layer at the center between adjacent fillers, and a recess is formed on the surface of the resin layer around the contact.
The filler-containing film according to claim 5 or 6, wherein the ratio (Lf / D) of the depth Lf from the tangential plane of the dent to the particle diameter D of the filler is less than 10%.
The filler-containing film according to any one of claims 1 to 7, wherein the ratio (La / D) between the layer thickness La of the resin layer and the particle diameter D of the filler is 0.6 to 10.
The ratio (Lb / D) between the distance Lb of the deepest part of the filler from the tangent plane at the center between adjacent fillers on the surface where the dents of the resin layer are formed and the particle diameter D of the filler (Lb / D) is 60% or more. The filler-containing film according to any one of claims 1 to 8, which is 105% or less.
The filler-containing film according to any one of claims 1 to 9, wherein the fillers are arranged in a non-contact manner.
The filler-containing film according to any one of claims 1 to 10, wherein the distance between the closest particles of the filler is 0.5 times or more the particle diameter of the filler.
The filler-containing film according to any one of claims 1 to 11, wherein a second resin layer is laminated on the surface of the filler dispersion layer opposite to the surface where the dents of the resin layer are formed.
The filler-containing film according to any one of claims 1 to 11, wherein a second resin layer is laminated on the surface of the filler-dispersed layer where the dent of the resin layer is formed.
The filler-containing film according to claim 12 or 13, wherein the minimum melt viscosity of the second resin layer is lower than the minimum melt viscosity of the resin layer of the filler dispersion layer.
The filler-containing film according to any one of claims 12 to 14, wherein the minimum melt viscosity ratio between the resin layer of the filler dispersion layer and the second resin layer is 2 or more.
The filler-containing film according to any one of claims 1 to 15, wherein the resin layer of the filler dispersion layer has a viscosity of 3000 to 20000 Pa · s at 60 ° C.
The filler-containing film according to claim 1, wherein the filler is a conductive particle, the resin layer of the filler dispersion layer is an insulating resin layer, and is used as an anisotropic conductive film.
A film sticking body in which the filler-containing film according to any one of claims 1 to 17 is stuck to an article.
A connection structure in which the first article and the second article are connected via the filler-containing film according to any one of claims 1 to 17.
The connection structure according to claim 19, wherein the first electronic component and the second electronic component are anisotropically conductively connected through the filler-containing film according to claim 17.
A method for producing a connection structure, wherein the first article and the second article are pressure-bonded via the filler-containing film according to any one of claims 1 to 17.
The first electronic component and the second electronic component are first electronic component and second electronic component, respectively, and the first electronic component and the second electronic component are thermocompression bonded through the filler-containing film according to claim 17. The manufacturing method of the connection structure of Claim 21 which manufactures the connection structure in which the 2nd electronic component and anisotropic conductive connection were manufactured.
A method for producing a filler-containing film having a step of forming a filler dispersion layer in which a filler is dispersed in a resin layer,
The step of forming the filler dispersion layer is a step of holding the filler on the surface of the resin layer;
Having a step of pushing the filler held on the surface of the resin layer into the resin layer;
In the step of holding the filler on the surface of the resin layer, the filler is held on the surface of the resin layer in a state where the filler is dispersed,
In the step of pushing the filler into the resin layer, the viscosity of the resin layer when pushing the filler so that the surface of the resin layer in the vicinity of the filler has a dent with respect to the tangent plane of the resin layer at the center between adjacent fillers, The manufacturing method of the filler containing film which adjusts indentation speed or temperature.
24. The production of a filler-containing film according to claim 23, wherein in the step of holding the filler on the surface of the resin layer, a resin layer having a minimum melt viscosity of 1100 Pa · s or higher and a viscosity at 60 ° C. of 3000 Pa · s or higher is used as the resin layer. Method.
In the step of holding the filler on the surface of the resin layer, the filler is held on the surface of the resin layer in a predetermined arrangement,
The method for producing a filler-containing film according to claim 23 or 24, wherein, in the step of pushing the filler into the resin layer, the filler is pushed into the resin layer with a flat plate or a roller.
The step of holding the filler on the surface of the resin layer fills the transfer mold with the filler, and transfers the filler to the resin layer to hold the filler on the surface of the resin layer in a predetermined arrangement. The manufacturing method of the filler containing film of crab.
The filler-containing film according to any one of claims 23 to 26, wherein conductive particles are used as the filler, an insulating resin layer is used as the resin layer of the filler dispersion layer, and an anisotropic conductive film is produced as the filler-containing film. Production method.