TW202227543A - Film containing filler - Google Patents

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

Filled film

The present invention relates to a filler-containing film.

Filler-containing films in which fillers are dispersed in a resin layer are used in various applications such as matte films, capacitor films, optical films, label films, antistatic films, and anisotropic conductive films (Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4). In terms of optical properties, mechanical properties, or electrical properties, it is desirable to suppress unnecessary resin formation of the filler-containing film when the filler-containing film is press-bonded to the article to be adhered to the filler-containing film. Resin flows and suppresses the presence of segregation of fillers. Especially in the case where conductive particles are contained as fillers and the filler-containing film is made into an anisotropic conductive film used for the packaging of electronic parts such as IC chips, if the conductive particles are made in a way that can cope with the high packaging density of electronic parts When the conductive particles are dispersed at high density in the insulating resin layer, the conductive particles dispersed at high density will move unnecessarily due to the flow of the resin during the assembly of electronic parts, so that there is segregation between terminals, which is the main cause of short circuit.

In this regard, in order to reduce short circuits and improve workability when preliminarily press-bonding an anisotropic conductive film to a substrate, it has been proposed to laminate a photocurable resin layer in which conductive particles are embedded in a single layer and an insulating adhesive layer. formed anisotropic conductive film (Patent Document 5). As a method of using the anisotropic conductive film, pre-bonding is performed in a state where the photocurable resin is not cured and has viscosity, and then the photocurable resin layer is photocured to fix the conductive particles, and then the substrate and the electronic Parts are officially crimped.

In addition, in order to achieve the same object as Patent Document 5, there is also proposed a three-layer structure in which a first connection layer is sandwiched between a second connection layer mainly composed of an insulating resin and a third connection layer. conductive film (Patent Documents 6 and 7). Specifically, with regard to the anisotropic conductive film of Patent Document 6, the first connection layer has a structure in which conductive particles are arranged in a single layer in the plane direction on the side of the second connection layer of the insulating resin layer, and the adjacent conductive particles are arranged in a single layer. The thickness of the insulating resin layer in the central region is thinner than the thickness of the insulating resin layer near 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 undulating, and the first connection layer has "the plane direction on the third connection layer side of the insulating resin layer is In the structure of "conductive particles arranged in a single layer", the thickness of the insulating resin layer in the central region between adjacent conductive particles is thinner than the thickness of the insulating resin layer near the conductive particles. prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2006-15680 Patent Document 2: Japanese Patent Laid-Open No. 2015-138904 Patent Document 3: Japanese Patent Laid-Open No. 2013-103368 Patent Document 4: Japanese Patent Laid-Open No. 2014-183266 Patent Document 5: Japanese Patent Laid-Open No. 2003-64324 Patent Document 6: Japanese Patent Laid-Open No. 2014-060150 Patent Document 7: Japanese Patent Laid-Open No. 2014-060151

[The problem to be solved by the invention]

However, the anisotropic conductive film described in Patent Document 5 has the following problems: the conductive particles are easily moved during the pre-compression bonding of the anisotropic conductive connection, and the anisotropic conductive connection before the anisotropic conductive connection cannot be maintained after the anisotropic conductive connection. The precise arrangement of the conductive particles, or the distance between the conductive particles cannot be sufficiently separated. In addition, if the photo-curable resin layer is photo-cured after the anisotropic conductive film is preliminarily bonded to the substrate, and the photo-cured resin layer embedded with conductive particles is attached to the electronic component, there is a problem of “in the It is difficult to capture conductive particles at the ends of bumps of electronic components, or there is a problem that "conductive particles require too much force to be pressed in, and conductive particles cannot be pressed in enough". In addition, in Patent Document 5, studies from the viewpoint of exposing the conductive particles from the photocurable resin layer in order to improve the pressing-in of the conductive particles are insufficient.

Therefore, in place of the photocurable resin layer, the conductive particles are dispersed in an insulating resin layer with a high viscosity at the heating temperature during anisotropic conductive connection, and the flow of conductive particles during anisotropic conductive connection is suppressed. properties, and improve workability when bonding the anisotropic conductive film to electronic parts. However, even if the conductive particles are temporarily and precisely arranged in such an insulating resin layer, if the resin layer flows during the anisotropic conductive connection, the conductive particles will also flow simultaneously, so it is difficult to sufficiently improve the trapping properties of the conductive particles. Or the reduction of short circuits makes it difficult to maintain the initial precise arrangement of the conductive particles after anisotropic conductive connection, and it is also difficult to keep the conductive particles separated from each other.

In addition, in the case of the three-layer structure anisotropic conductive film described in Patent Documents 6 and 7, no problem was found with respect to the fundamental point of anisotropic conductive connection properties, but because of the three-layer structure, the manufacturing cost was high. From a viewpoint, reduction of the number of manufacturing steps is sought. In addition, in the vicinity of the conductive particles on one side of the first connection layer, the whole or a part of the first connection layer is greatly raised along the outer shape of the conductive particles, and the insulating resin layer constituting the first connection layer itself is not flat. Since the conductive particles are held in the raised portion, there is a possibility that the design constraints for retaining the conductive particles and improving the catchability by the terminal will increase.

On the other hand, the subject of the present invention is to use a filler-containing film in which a filler such as conductive particles is dispersed in a resin layer, even if the three-layer structure is not required, and even if the resin is not used in the vicinity of the filler holding the filler resin. The whole or part of the layer is significantly raised compared to the outer shape of the filler, which will also inhibit the flow of the filler caused by the unnecessary flow of the resin layer when the filler-containing film is crimped to the article. When the anisotropic conductive film is formed, the unnecessary flow of conductive particles during thermocompression bonding between the anisotropic conductive film and electronic components is suppressed, the ability to capture conductive particles of the terminal is improved, and short circuits are reduced. [Technical means to solve the problem]

The inventors of the present invention have obtained the following findings on the relationship between the surface shape near the filler in the resin layer and the viscosity of the resin layer regarding a filler-containing film having a "filler-dispersed layer in which a filler such as conductive particles is dispersed in the resin layer". That is, it was found that, with respect to the anisotropic conductive film described in Patent Document 5, the surface of the insulating resin layer (that is, the photocurable resin layer) itself on the side where the conductive particles are embedded becomes flat, and (i) the conductive When fillers such as particles are exposed from the resin layer, if the surface of the resin layer around the filler is concave with respect to the tangent plane of the resin layer in the central portion between adjacent fillers, the concave portion becomes a part of the surface of the resin layer The defective state can reduce unnecessary insulating resins that may hinder the bonding of the filler and the article when the filler-containing film is bonded to the article by crimping the filler-containing film to the article; and (ii) When the filler is not exposed from the resin layer and is buried in the resin layer, if the surface of the resin layer directly above the filler forms a ripple-like trace that is regarded as a trace of the filler being buried in the resin layer If there are undulations, the amount of resin in the concave portion of the undulations decreases, and when the filler-containing film is crimped to the article, the filler is easily pressed into the article by the article; (iii) Therefore, if the two opposite articles are pressed through the filler-containing film In this way, the packing held by the opposite article is well connected to the article, in other words, the catching property of the packing of the article, or the consistency of the arrangement state of the packing held by the article before and after crimping is improved, which makes it easier to carry out Inspection of products containing filler films, or confirmation of use surfaces. Furthermore, it was found that in the case of forming the filler dispersion layer by laminating the filler into the resin, such a recess in the resin layer can be formed by adjusting the viscosity of the resin layer into which the filler is pressed.

Based on the above findings, the present invention provides a filler-containing film having a filler-dispersed layer in which a filler is dispersed in a resin layer, and The surface of the resin layer near the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between the adjacent fillers, especially to provide a film in which the surface of the resin layer around the filler is relative to the above-mentioned tangent plane. Defects, or the resin amount of the resin layer just above the filler becomes smaller than when the surface of the resin layer just above the filler is located on the above-mentioned tangent plane.

Furthermore, the present invention provides a method for producing a filler-containing film, which has the step of forming a filler-dispersed layer in which a filler is dispersed in a resin layer, The step of forming the filler-dispersed layer includes the step of holding the filler on the surface of the resin layer, and The step of pressing the filler held on the surface of the resin layer into the resin layer, In the step of keeping the filler on the surface of the resin layer, the filler is kept on the surface of the resin layer in a state where the filler is dispersed, and In the step of burying the filler in the resin layer, the resin layer when the filler is embedded is adjusted so that the surface of the resin layer near the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between the adjacent fillers In particular, a method of manufacturing a film containing a filler is provided, and as the recess, the surface of the resin layer around the filler is formed in a state where the surface of the resin layer is deficient relative to the above-mentioned tangent plane, or the amount of resin in the resin layer directly above the filler is provided. It is less than when the surface of the resin layer directly above the filler is located in the above-mentioned tangential plane. [Effect of invention]

The filler-containing film of the present invention has a filler-dispersed layer in which a filler is dispersed in a resin layer. In the filler-dispersed layer, the surface of the resin layer in the vicinity of the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between adjacent fillers. That is, when the filler is exposed from the resin layer, the surface of the resin layer around the exposed filler has a concave portion, the concave portion is in a state where the resin layer is deficient with respect to the tangential plane, and the amount of resin decreases. Furthermore, when the filler is not exposed from the resin layer and is buried in the resin layer, the surface of the resin layer just above the filler has a recess, and the resin amount in the recess is reduced relative to the tangent plane.

Therefore, if the resin layer has a concave portion around the filler exposed from the resin layer, the amount of resin in the concave portion decreases, thereby reducing the flow of resin when the filler-containing film is crimped to the article, and the filler becomes easy to crimp. to the item. Furthermore, when the two articles are crimped via the filler-containing film, the resin is less likely to be a hindrance to sandwiching the filler or flattening the filler. In addition, in accordance with the reduction in the amount of resin around the filler by the concave portion, the resin flow associated with the unnecessary flow of the filler is reduced. Thereby, the trapping property of the filler of the article is improved, and especially when the filler-containing film is constituted as an anisotropic conductive film, the trapping property of the conductive particles of the terminal is improved, thereby improving the conduction reliability.

In addition, if the resin layer just above the filler embedded in the resin layer has a concave portion, it is easy to apply a pressing force from the article to the filler when the filler-containing film is crimped to the article. In addition, in accordance with the reduction of the amount of resin directly above the filler by the recess, the resin flow associated with causing the filler to flow unnecessarily is reduced. Therefore, in this case, the trapping property of the filler of the article is also improved, especially when the filler-containing film is formed as an anisotropic conductive film, that is, when conductive particles are dispersed as fillers in the insulating resin layer. In this case, the capture property of the conductive particles of the terminal is improved, thereby improving the conduction reliability.

In this way, according to the filler-containing film of the present invention, the trapping property of the filler is improved, and the filler does not flow easily on the article, so that the arrangement of the filler can be precisely controlled. Therefore, when the filler-containing film is formed as an anisotropic conductive film, the arrangement of the conductive particles can be precisely controlled with respect to the terminals, so that, for example, it can be used for a terminal width of 6 μm to 50 μm and an interval between terminals of 6 μm to 50 μm. The connection of electronic components with fine pitch. In addition, if 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 part in plan view among the widths of the opposite pair of terminals during connection) is 3 μm or more, and the shortest terminal When the distance between them is 3 μm or more, electronic components can be connected without short-circuiting.

In addition, since the arrangement of the conductive particles can be precisely controlled, when connecting electronic components with standard pitches, the arrangement of the conductive particles, or the layout of the area where the number density of the conductive particles is changed, and the relationship between various electronic components can be made. The layout of the terminals corresponds.

Furthermore, in the filler-containing film of the present invention, if the resin layer immediately above the filler embedded in the resin layer has a concave portion, the position of the filler can be clearly known by the external observation of the filler-containing film, so it is easy to carry out Using the product inspection of the appearance, it is also easy to identify the front and back of the film surface. Therefore, when the filler-containing film is crimped to the article, it is easy to confirm the use surface of "which film surface of the filler-containing film is to be attached to the article". The same advantages can also be obtained in the case of manufacturing filled films.

In addition, according to the filler-containing film of the present invention, it is not necessary to photoharden the resin layer in advance in order to fix the arrangement of the filler, so that the resin layer can have adhesiveness when the filler-containing film is crimped to an article. Therefore, in the case where the filler-containing film and the article are pre-crimped and then the actual crimping is performed, the workability during the pre-crimping is improved, and when the article is fully crimped after the pre-crimping, the workability is also improved.

On the other hand, according to the production method of the present invention, the viscosity, the pressing speed or the temperature of the resin layer when the filler is embedded in the resin layer is adjusted so as to form the above-mentioned concave portion in the resin layer. Therefore, the filler-containing film of the present invention which exhibits the above-mentioned effects can be easily produced.

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 structure of filler-containing film> FIG. 1A is a top view illustrating the arrangement of the filler of the filler-containing film 10A according to an embodiment of the present invention, and FIG. 1B is a XX cross-sectional view thereof. The filler-containing film 10A is used as an anisotropic conductive film, and is formed by dispersing conductive particles as the filler 1 in the insulating resin layer 2 .

In the present invention, the filler-containing film 10A such as an anisotropic conductive film may be in the form of a long film having a length of 5 m or more, or may be in a package that is wound into a core.

The filler-containing film 10A is composed of the filler-dispersed layer 3 , and in the filler-dispersed layer 3 , the filler 1 is regularly dispersed in a state of being exposed on one side of the resin layer 2 . In the top view of the film, the fillers 1 are not in contact with each other, and in the film thickness direction, the fillers 1 are also regularly dispersed without overlapping each other, forming a single-layer filler layer in which the positions of the fillers 1 in the film thickness direction are aligned.

On the surface 2a of the resin layer 2 around each filler 1, a concave portion 2b is formed with respect to the tangent plane 2p of the resin layer 2 on the central portion between the adjacent fillers. Furthermore, as will be described later, the filler-containing film of the present invention may have recesses 2c 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 dispersion state of the filler in the present invention includes both the state in which the filler 1 is randomly dispersed, and the state in which the filler 1 is dispersed in a regular arrangement. In either case, the positional alignment in the film thickness direction is preferable in terms of capturing stability. Here, the so-called positional alignment of the filler 1 in the film thickness direction is not limited to the positional alignment of the filler 1 at a single depth in the film thickness direction, including the presence of fillers at the front and back interfaces of the resin layer 2 or their vicinity. 1 state.

In addition, in order to make the optical, mechanical or electrical properties of the filler-containing film uniform, especially when the filler-containing film is used as an anisotropic conductive film, in terms of suppressing short circuits, it is preferable to use the filler 1 in the plan view of the film. Arranged regularly. The arrangement pattern can be determined according to the crimping of the article containing the filler film. For example, in the anisotropic conductive film, the arrangement pattern of the conductive particles can be determined according to the layout of the terminals and bumps. Therefore, the arrangement pattern of the conductive particles is not the same. There is no particular limitation. For example, the film can be arranged in a square lattice as shown in FIG. 1A in a plan view of the film. In addition, as an aspect of the regular arrangement of the fillers, lattice arrangements such as rectangular lattices, rhombic lattices, hexagonal lattices, and triangular lattices can be exemplified. It can also be a combination of lattices of various shapes. As an aspect of the arrangement of the fillers, the particle rows in which the fillers are linearly arranged at specific intervals may be juxtaposed at specific intervals. Moreover, it may be in the form where the vacancy of the filler regularly exists in the specific direction of a film.

When the fillers 1 are not in contact with each other and are regularly arranged in a grid shape, when the filler-containing film is crimped to the article, pressure is equally applied to each of the fillers 1, thereby reducing the uneven connection state. In addition, batch management can be achieved by making the vacancies of the fillers repeatedly exist in the longitudinal direction of the film, or by gradually increasing or decreasing the vacancies of the fillers in the longitudinal direction of the film, and can also be used for filler-containing films and applications. Its connection structure grants tracking ability (the property of being able to track). It is also effective for preventing counterfeiting of filler-containing films or connecting structures using the same, determining authenticity, preventing unauthorized use, and the like.

Therefore, in the anisotropic conductive film, by arranging the conductive particles regularly, it is possible to reduce unevenness in on-resistance when connecting electronic components using the anisotropic conductive film. In addition, in order to achieve capture stability and suppression of short circuits at the same time, it is more preferable that the conductive particles are regularly arranged in a plan view of the film, and the positions in the film thickness direction are aligned.

On the other hand, when the distance between the terminals of the electronic components to be connected is large and short-circuiting is unlikely to occur, the conductive particles may not be regularly arranged but randomly dispersed.

In the case where the fillers are regularly arranged in the filler-containing film, the grid axis or the arrangement axis of the arrangement may be parallel to the longitudinal direction of the film, or parallel to the direction orthogonal to the longitudinal direction, or parallel to the longitudinal direction of the film. The cross in the longitudinal direction can be determined according to the articles to be connected, and when the filler-containing film is used as an anisotropic conductive film, it can be determined according to the terminal width, terminal pitch, and the like. For example, in the case of an anisotropic conductive film for fine pitch, as shown in FIG. 1A , the lattice axis A of the conductive particles 1 is inclined with respect to the longitudinal direction of the anisotropic conductive film 10A, so that the The angle θ formed by the long-side direction (short-side direction of the film) of the terminal 20 connected to the conductive film 10A 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 items to be connected. When the filler-containing film is used as an anisotropic conductive film, the distance between the fillers can be determined according to the size of the terminals connected by the anisotropic conductive film or The inter-particle distance between the conductive particles 1 is appropriately determined according to the terminal pitch. For example, when the anisotropic conductive film is made to correspond to a micro-pitch COG (Chip On Glass, chip on glass), it is preferable to set the distance between the closest particles to be conductive in terms of preventing short circuit The particle diameter D is 0.5 times or more, more preferably 0.7 times or more. On the other hand, the upper limit of the distance between the closest particles can be determined according to the purpose of the filler-containing film. The distance is set to be 100 times or less, more preferably 50 times or less, of the diameter D of the conductive particles. In addition, in terms of the ability to capture the conductive particles 1 of the terminal during anisotropic conductive connection, the distance between the closest particles is preferably 4 times or less the diameter D of the conductive particles, and more preferably 3 times or less.

Moreover, in the filler-containing film of the present invention, the area occupancy rate of the filler calculated from the following formula is preferably 35% or less, more preferably 0.3 to 30%. Area occupancy rate (%) = [number density of fillers in plan view] × [average of the plan area of 1 filler] × 100

Here, as the measurement area of the number density of the filler, it is preferable to arbitrarily set a rectangular area with one side of 100 μm or more at a plurality of locations (preferably 5 locations or more, more preferably 10 locations or more), In addition, the total area of the measurement regions is set to be 2 mm ² or more. The size or number of each area may be appropriately adjusted according to the state of the number density. For example, as an example of the case where the number density of anisotropic conductive films for micro-pitch applications is relatively large, 200 sites (2 mm ² ), the number density of the conductive particles in the above-mentioned formula can be obtained by measuring the number density using the observation image obtained by using a metal microscope, etc., and averaging them. A region with an area of 100 μm×100 μm is a region where one or more bumps exist in a connection object with an inter-bump interval of 50 μm or less.

Furthermore, if the area occupancy rate is within the above-mentioned range, the value of the number density is not particularly limited. When the filler-containing film is used as an anisotropic conductive film, in practical application, the number density is 30. /mm ² or more, preferably 150-70,000 pieces/mm ² , especially in the case of micro-pitch applications, preferably 6,000-42,000 pieces/mm ² , more preferably 10,000-40,000 pieces/mm ² , and further More preferably, it is 15,000 to 35,000 pieces/mm ² .

The number density of fillers can be obtained by measuring the observed image with image analysis software (eg, WinROOF, Mitani Corporation, etc.), in addition to the observation using a metal microscope as described above. The observation method or the measurement method is not limited to the above.

In addition, the average value of the top view area of 1 filler is calculated|required by the observation image obtained by the metal microscope, SEM, etc. which measure the film surface. Image analysis software can also be used. The observation method or the measurement method is not limited to the above.

The area occupancy is an index of the thrust required for the pressing jig in order to crimp the filler-containing film to the article, and is preferably 35% or less, more preferably 0.3 to 30%. The reason for this is as follows. That is, in the anisotropic conductive film, in order to cope with the fine pitch, the distance between the particles of the conductive particles is reduced within the range where short circuit does not occur, and the number density is increased. However, if the number density is increased in this way, the number of terminals of electronic components increases, and the total area of connection per electronic component increases. Accordingly, in order to press-bond the anisotropic conductive film to the electronic components, a pressing jig is required for pressing The required thrust increases, and there is a possibility that the pressing of the previous pressing jig becomes insufficient. The problem of the thrust required for pressing the jig is not limited to the anisotropic conductive film, but is the same for all filler-containing films. On the other hand, by setting the area occupancy rate to preferably 35% or less, and more preferably 30% or less as described above, it is possible to suppress the thrust required for the pressing jig in order to press-bond the filler-containing film to the article. lower.

＜Packing＞ In the present invention, filler 1 is selected from known inorganic fillers (metals, metal oxides, metal nitrides, etc.), organic fillers (resin particles, rubber particles, etc.), organic materials mixed with Fillers of inorganic materials (for example, the core is formed of a resin material, the surface is plated with metal particles (metal-coated resin particles), the surface of the conductive particles is adhered with insulating fine particles, and the surface of the conductive particles is obtained by insulating the surface. etc.), it is appropriately selected according to the properties required in the application such as hardness and optical properties. For example, silica fillers, titanium oxide fillers, styrene fillers, acrylic fillers, melamine fillers, or various titanates, etc. may be used for optical films or matte films. As the film for capacitors, titanium oxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium titanate zirconate, lead titanate zirconate, and the like can be used. mixture, etc. Next, the film may contain polymer-based rubber particles, polysiloxane 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 adhered to the surface. You can also use 2 or more types together. Among them, the metal-coated resin particles are preferred because the resin particles rebound after the connection, so that the contact with the terminals is easily maintained, and the conduction performance is stable. In addition, the surface of the conductive particle may be subjected to an insulating treatment that does not hinder the conduction characteristics by a known technique. The fillers listed in the above application types are not limited to this application, and may also contain filler-containing films for other applications as required. Moreover, the filler-containing film of each application may use two or more types of fillers in combination as needed.

The particle size D of the filler 1 is appropriately determined according to the application of the filler-containing film. For example, the anisotropic conductive film is preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and 9 μm or less.

The particle size D of the filler before being dispersed in the resin layer 2 can be measured by a general particle size distribution analyzer, and the average particle size can also be determined using a particle size distribution analyzer. As an example of a particle size distribution measuring apparatus, FPIA-3000 (Malvern Corporation) can be mentioned. On the other hand, the particle size D of the filler in the filler-containing film (that is, the particle size D after dispersing the filler in the resin layer) can be determined by observation with an electron microscope such as SEM. In this case, it is preferable to set the number of samples for measuring the particle diameter D to 200 or more. In addition, when the shape of the filler is not spherical, the maximum length or the diameter that resembles the shape of a sphere can be used as the particle size D of the filler based on a plane image or a cross-sectional image.

Furthermore, for example, in order to improve the insulating properties of the conductive particles of the anisotropic conductive film, when insulating fine particles adhered to the surface of the conductive particles are used as fillers, the particle size of the fillers in the present invention means that the insulating particles on the surface are not included. The particle size of the microparticles.

<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 application of the filler-containing film, the manufacturing method of the filler-containing film, and the like. For example, as long as the above-mentioned concave portions 2b and 2c can be formed, it may be set to about 1000 Pa·s by the manufacturing method of the filler-containing film. On the other hand, as a method for producing a filler-containing film, when a method of holding a filler on the surface of a resin layer in a specific arrangement and pressing the filler into the resin layer is performed, the resin layer can be formed into a film. , preferably the minimum melt viscosity of the resin is set to 1100 Pa∙s or more.

Further, as described in the method for producing a film containing a filler to be described later, as shown in FIG. 1B and the like, a concave portion 2b is formed around the exposed portion of the filler 1 pressed into the resin layer 2, or as shown in FIGS. 4 and 6 . In general, in terms of forming the concave portion 2c directly above the filler 1 pressed into the resin layer 2, it is preferably 1500 Pa∙s or more, more preferably 2000 Pa∙s or more, and still more preferably 3000 to 15000 Pa∙s s, more preferably 3000 to 10000 Pa∙s. As an example, the minimum melt viscosity can be obtained by using a rotational rheometer (manufactured by TA Instruments), keeping it constant at a measurement pressure of 5 g, and using a measurement plate with a diameter of 8 mm. More specifically, it can be obtained by In the temperature range of 30 to 200° C., the temperature increase rate was 10° C./min, the measurement frequency was 10 Hz, and the load on the measurement plate was changed by 5 g.

By setting the minimum melt viscosity of the resin layer 2 to a high viscosity of 1500 Pa∙s or more, unnecessary movement of the filler can be suppressed in the crimping of the filler-containing film to the article, especially when the filler-containing film is set to anisotropic In the case of a conductive film, the conductive particles that should be held between the terminals during anisotropic conductive connection can be prevented from flowing due to resin flow.

Furthermore, in the case where the filler dispersion layer 3 of the filler-containing film 10A is formed by pressing the filler 1 into the resin layer 2 , the resin layer 2 when the filler 1 is pressed is exposed so that the filler 1 is exposed from the resin layer 2 . When the filler 1 is pressed into the resin layer 2, the resin layer 2 is plastically deformed and a concave portion 2b is formed in the resin layer 2 around the filler 1 (Fig. 1B). When the filler 1 is embedded in the resin layer 2 without being exposed from the resin layer 2 , it becomes a high-viscosity viscous body as if the concave portion 2 c ( FIG. 6 ) was formed on the surface of the resin layer 2 directly above the filler 1 . Therefore, the lower limit of the viscosity of the resin layer 2 at 60°C is preferably 3000 Pa∙s or higher, more preferably 4000 Pa∙s or higher, further preferably 4500 Pa∙s or higher, and the upper limit is preferably 20000 Pa∙s or lower, More preferably, it is 15000 Pa∙s or less, and still more preferably 10000 Pa∙s or less. This measurement is performed by the same measurement method as 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 pressed into the resin layer 2 corresponds to the shape or depth of the formed recesses 2b and 2c, and the lower limit is preferably 3000 Pa∙s or more, more preferably 4000 Pa∙s Above, 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 still more preferably 10000 Pa∙s or less. Moreover, it is preferable that such a viscosity is obtained at 40-80 degreeC, More preferably, it is 50-60 degreeC.

As described above, since the concave portion 2b is formed around the filler 1 exposed from the resin layer 2 ( FIG. 1B ), the flattening of the filler 1 generated when the filler-containing film is press-bonded to the article has a higher resistance from the resin. When there is no recessed part 2b, it falls. Therefore, when the filler-containing film is used as the anisotropic conductive film, it becomes easy to sandwich the conductive particles between the terminals during anisotropic conductive connection, thereby improving the conduction performance and improving the capture property.

Moreover, since the surface of the resin layer 2 just above the filler 1 which is hidden from being exposed from the resin layer 2 is formed with the concave portion 2c ( FIG. 4 , FIG. 6 ), compared with the case where the concave portion 2c is not present, the filler-containing film is more effective for articles. The pressure during the crimping is easy to concentrate on the filler 1. Therefore, when the filler-containing film is used as an anisotropic conductive film, it becomes easy to sandwich the conductive particles with the terminals at the time of anisotropic conductive connection, thereby improving the trapping property and improving the conduction performance.

(layer thickness of resin layer) In the filler-containing film of the present invention, 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 to 10. Here, the particle diameter D of the filler 1 refers to its average particle diameter. If the layer thickness La of the resin layer 2 is too large, the positional displacement of the filler is likely to occur when the filler-containing film is pressed against the article. Therefore, when the filler-containing film is used as an optical film, unevenness in optical properties occurs. Moreover, in the case where the filler-containing film is used as an anisotropic conductive film, the captureability of the conductive particles of the terminal at the time of anisotropic conductive connection decreases. This tendency is remarkable when La/D exceeds 10. Therefore, La/D is more preferably 8 or less, and still more preferably 6 or less. Conversely, 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 specific particle dispersion state or a specific arrangement by the resin layer 2 . Therefore, when the filler-containing film is used as an anisotropic conductive film, especially when the connected terminals are high-density COG, the ratio of the layer thickness La of the insulating resin layer 2 to the particle size D of the conductive particles 1 (La /D) is preferably 0.8 to 2. On the other hand, when the risk of short circuit generation is considered to be low from the bump layout of the 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 may be formed of 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 made insulating is also determined according to the use of the filler-containing film.

Here, the curable resin composition can be formed from, for example, a thermally polymerizable composition containing a thermally polymerizable compound and a thermally polymerizable initiator. The thermally polymerizable composition may also contain a photopolymerization initiator if necessary.

When a thermal polymerization initiator and a photopolymerization initiator are used in combination, those that function as a thermally polymerizable compound and also function as a photopolymerizable compound may be used, or a photopolymerizable compound may be included in addition to the thermally polymerizable compound. sexual compounds. It is preferable to contain a photopolymerizable compound in addition to a thermopolymerizable compound. For example, a cationic curing initiator is used as a thermal polymerization initiator, an epoxy resin is used as a thermal polymerizable compound, a photoradical initiator is used as a photopolymerization initiator, and an acrylate compound is used as a photopolymerizable compound.

As the photopolymerization initiator, a plurality of photopolymerization initiators that react with light having different wavelengths may be contained. Thereby, in the manufacture of the filler-containing film, the wavelengths used for the photocuring of the resin for forming the resin layer into a film and the photocuring of the resin for crimping the filler-containing film to the article can be separately used.

In the photocuring at the time of manufacture of the filler-containing film, all or a 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 the suppression of short circuits and the improvement of trapping properties can be expected. Moreover, the viscosity of the resin layer in the manufacturing process of a filler containing film can also be adjusted suitably by this photohardening.

The blending 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. The reason for this is that when there are too many photopolymerizable compounds, the thrust required for press-fitting when the filler-containing film and the article are crimped increases.

Examples of the thermally polymerizable composition include: a thermally polymerizable acrylate-based composition containing a (meth)acrylate compound and a thermal radical polymerization initiator, a thermally polymerizable acrylate-based composition containing an epoxy compound and a thermal cationic polymerization initiator Thermal cationic polymerizable epoxy-based composition of the agent, etc. In place of the thermally cationically polymerizable epoxy-based composition containing a thermally cationic polymerization initiator, a thermally anionic polymerizable epoxy-based composition containing a thermally anionic polymerization initiator may also be used. Moreover, as long as there is no particular hindrance, a plurality of polymerizable compositions may be used in combination. As an example of combined use, the combined use of a thermally cationically polymerizable compound and a thermally radically polymerizable compound, etc. may be mentioned.

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

As a thermal radical polymerization initiator, an organic peroxide, an azo type compound, etc. are mentioned, for example. In particular, an organic peroxide that does not generate nitrogen gas which causes bubbles can be preferably used.

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

Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, modified epoxy resins thereof, alicyclic epoxy resins, etc., and may be used in combination Two or more of these. Moreover, in addition to an epoxy compound, an oxetane compound may be used together.

As the thermal cationic polymerization initiator, known thermal cationic polymerization initiators for epoxy compounds can be used, for example, iodonium salts, perylene salts, phosphonium salts, ferrocenes, etc. which generate acids by heat can be used, especially It is preferable to use an aromatic perionium salt which shows good latency with respect to temperature.

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

As the thermal anionic polymerization initiator, a commonly used well-known hardener can be used. For example, organic acid dihydrazide, dicyandiamide, amine compound, polyamide amine compound, cyanate ester compound, phenol resin, acid anhydride, carboxylic acid, tertiary amine compound, imidazole, Lewis acid, Brunsted acid Salts, polythiol-based curing agents, urea resins, melamine resins, isocyanate compounds, blocked isocyanate compounds and the like may be used alone or in combination of two or more. Among these, it is preferable to use a microcapsule-type latent hardener in which an imidazole modified body is used as a core and whose surface is coated with polyurethane.

The thermally polymerizable composition preferably contains a film-forming resin or a silane coupling agent. Examples of film-forming resins include phenoxy resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, urethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefins. Resin etc., these 2 or more types can be used together. Among these, a phenoxy resin can be preferably used from the viewpoints of film formability, workability, and connection reliability. The weight average molecular weight is preferably 10,000 or more. Moreover, as a silane coupling agent, an epoxy-type silane coupling agent, an acryl-type silane coupling agent, etc. are mentioned. These silane coupling agents are mainly alkoxysilane derivatives.

In order to adjust the melt viscosity, the thermally polymerizable composition may contain an insulating filler in addition to the above-mentioned filler 1 . It can be exemplified by silica powder, alumina powder, and the like. The insulating filler is preferably a small filler with a particle size of 20 to 1000 nm, and the blending amount is preferably 5 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable composition) such as an epoxy compound. ~50 parts by mass. The insulating filler contained in addition to the filler 1 can be preferably used in the case where the application of the filler-containing film is an anisotropic conductive film, but depending on the application, it may not be insulating. filler. When the filler-containing film is used as an anisotropic conductive film, a finer insulating filler (so-called nanofiller) different from the filler 1 may be appropriately contained in the resin layer forming the filler-dispersed layer as necessary.

The filler-containing film of the present invention may contain fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion scavengers, etc. in addition to the above-mentioned insulating or conductive fillers. .

<Position of the filler in the thickness direction of the resin layer> In the filler-containing film of the present invention, regarding the position of the filler 1 in the thickness direction of the resin layer 2, as described above, the filler 1 may be exposed from the resin layer 2, or it may not be exposed but buried in the resin layer 2, and the filler is the deepest The distance from the resin layer to the tangent plane 2p on the central portion between the adjacent fillers on the surfaces 2a of the resin layer on which the recesses 2b and 2c are formed (hereinafter referred to as the embedded amount) Lb to the ratio of the particle size D of the filler 1 (Lb /D) (hereinafter referred to as burying rate) is preferably 60% or more and 105% or less.

By setting the embedding ratio (Lb/D) to 60% or more, the filler 1 can be maintained in a specific particle dispersion state or a specific arrangement by the resin layer 2, and by setting it to 105% or less, the filler 1 can be reduced. The amount of resin in the resin layer that acts in such a way as to make the filler flow unnecessarily when the filler-containing film is crimped to the article.

Furthermore, in the present invention, the numerical value of the embedded rate (Lb/D) refers to 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of fillers contained in the filler-containing film. Intake rate (Lb/D) value. Therefore, the term "embedding rate of 60% or more and 105% or less" means that the embedding rate is 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of fillers contained in the filler-containing film. % or more and less than 105%.

By making the embedding ratio (Lb/D) of all the fillers uniform in this way, the pressing load when the film containing the filler is crimped to the article is uniformly applied to the filler. Therefore, the film-bonded body obtained by crimping and bonding the filler-containing film to an article can ensure uniformity of quality such as optical properties and mechanical properties. Moreover, in the case where the filler-containing film is used as an anisotropic conductive film, the capture state of the conductive particles in the terminal at the time of anisotropic conductive connection becomes favorable, and the conduction stability improves.

The burial rate (Lb/D) can be arbitrarily extracted from the filler-containing film at 10 or more locations with an area of 30 ^mm2 or more, and a part of the film cross-section can be observed by SEM image, and a total of 50 or more The filler was measured and obtained. In order to further improve the accuracy, it can also be obtained by measuring more than 200 fillers.

In addition, the measurement of the burial rate (Lb/D) can be obtained at one time for a certain number of objects by adjusting the focus in the surface view image. Alternatively, a laser-type discriminating displacement sensor (manufactured by Keyence, etc.) can also be used for the measurement of the burial rate (Lb/D).

(Embedding rate of more than 60% and less than 100%) As a more specific embedment of the filler 1 having an embedment ratio (Lb/D) of 60% or more and 105% or less, first, as shown in FIG. 2 In the form of exposure, the embedding rate is more than 60% but not 100% embedded. With regard to the filler-containing film 10A, the portion of the surface of the resin layer 2 that is tangent to the filler 1 exposed from the resin layer 2 and its vicinity are relative to the tangent of the surface 2a of the resin layer on the central portion between the adjacent fillers The plane 2p has a concave portion 2b that is recessed in a mortar-like shape.

In the case of manufacturing the filler-containing film 10A having the concave portion 2b 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, 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 still more preferably 10000 Pa∙s or less. Moreover, it is preferable that such a viscosity is obtained at 40-80 degreeC, More preferably, it is 50-60 degreeC.

(The state of 100% burial rate) Next, as an aspect of the filling rate (Lb/D) of 100% in the filler-containing film of the present invention, there may be mentioned a filler-containing film 10B as shown in FIG. In the same mortar-shaped concave portion 2b of the filler-containing film 10A shown, the exposed diameter Lc of the filler 1 exposed from the resin layer 2 is smaller than the particle size D of the filler 1; like the filler-containing film 10C shown in FIG. 3A, the filler 1 The concave portion 2b around the exposed portion is steeply formed near the filler 1, and the exposed diameter Lc of the filler 1 is approximately equal to the particle size D of the filler; like the filler-containing film 10D shown in FIG. 4, on the surface of the resin layer 2 It has a shallow recess 2c, and the filler 1 is exposed from the resin layer 2 at one point of the top 1a.

In addition, a minute protrusion 2q may be formed adjacent to "the concave portion 2b of the resin layer 2 around the exposed portion of the filler" or "the concave portion 2c of the resin layer just above the filler". An example of this is shown in FIG. 3B .

Since the filling rate of the filler-containing films 10B, 10C, 10C', and 10D is 100%, the top 1a of the filler 1 and the surface 2a of the resin layer 2 are aligned on the same plane. If the top 1a of the filler 1 and the surface 2a of the resin layer 2 are aligned on the same plane, compared with the case where the filler 1 protrudes from the resin layer 2 as shown in FIG. , In the periphery of each filler, the amount of resin in the film thickness direction is not easy to become uneven, which can reduce the movement of the filler caused by the resin flow. Furthermore, 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 so as to be on the same plane. In other words, when the embedding ratio (Lb/D) is about 80-105%, especially 90-100%, the top of the filler 1 embedded in the resin layer 2 and the surface of the resin layer 2 can be said to be on the same plane, so the reduction of Movement of filler due to resin flow.

Among these filler-containing films 10B, 10C, and 10D, as for 10D, since the amount of resin around the filler 1 does not easily become uneven, the movement of the filler caused by the flow of the resin can be eliminated. 1 point, but the filler 1 is exposed from the resin layer 2, so the trapping property of the filler 1 of the article is also good. Therefore, when the filler-containing film is constituted as an anisotropic conductive film, the effect that the conductive particles captured to the terminal during anisotropic conductive connection are not easily produced even by a slight movement can be expected. Therefore, this aspect is particularly effective for an anisotropic conductive film used for a fine pitch or a narrow inter-bump space.

Furthermore, as will be described later, the filler-containing films 10B ( FIG. 2 ), 10C ( FIG. 3A ), and 10D ( FIG. 4 ) having different shapes and depths of the concave portions 2 b and 2 c can be formed by changing the resin layer when the filler 1 is pressed in. 2 viscosity, injection speed or temperature, etc.

(The state where the burial rate exceeds 100%) As an aspect of the filler-containing film of the present invention in which the burying rate exceeds 100%, the filler 1 is exposed like the filler-containing film 10E shown in FIG. 5 , and the resin layer 2 around the exposed portion has a relatively The concave portion 2b of the cut plane 2p; like the filler-containing film 10F shown in FIG. Those having the concave portion 2c with respect to the tangent plane 2p.

Furthermore, the resin layer 2 around the exposed portion of the filler 1 has a filler-containing film 10E ( FIG. 5 ) having a concave portion 2 b and a filler-containing film 10F having a concave portion 2 c on the resin layer 2 directly above the filler 1 ( FIG. 6 ) It can be manufactured by changing the viscosity of the resin layer 2 when the filler 1 is press-fitted, the press-fit speed, the temperature, etc. at the time of manufacture.

When the filler-containing film 10E shown in FIG. 5 is press-bonded with the article, the filler 1 is directly pressed from the article, so that the article and the filler are easily bonded. The isotropic conductive film improves the capture property of the conductive particles of the terminal when an electronic component is anisotropically conductively connected. Furthermore, when the filler-containing film 10F shown in FIG. 6 is pressed against the article, the filler 1 does not directly press the article, but presses through the resin layer 2, but the amount of resin in the pressing direction is the same as that in the state of FIG. 8 ( That is, the filler 1 is buried more than 100% of the filling rate, the filler 1 is not exposed from the resin layer 2, and the surface of the resin layer 2 is flat). The filler 1 moves unnecessarily due to resin flow when the article is crimped.

The concave portion 2b of the resin layer 2 around the exposed portion of the above-mentioned filler (Fig. 1B, Fig. 2, Fig. 3A, Fig. 3B, Fig. 5), or the concave portion 2c of the resin layer just above the filler (Fig. 4, Fig. 6) ), the ratio (Le/D) of the maximum depth Le of the concave portion 2b around the exposed portion of the filler 1 to the particle size D of the filler 1 is preferably less than 50%, more preferably less than 30%, more preferably 20 to 25%, and the ratio (Ld/D) of the maximum diameter Ld of the concave portion 2b around the exposed portion of the filler 1 to the particle size D of the filler 1 is preferably 100% or more, more It is preferably 100-150%, and the ratio (Lf/D) of the maximum depth Lf of the concave portion 2c in the resin directly above the filler 1 to the particle size D of the filler 1 is greater than 0, and preferably less than 10%, more preferably 5% or less.

In addition, the exposed diameter Lc of the filler 1 can be set to be equal to or smaller than the particle diameter D of the filler 1 , 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 becomes zero.

On the other hand, if the top of the filler 1 embedded in the resin layer 2 is substantially on the same plane as the surface of the resin layer 2, and the depths of the recesses 2b and 2c (the deepest part of the recesses are above the center part between the adjacent fillers) The distance between the tangent planes) is 10% or more of the particle size of the filler (hereinafter referred to as "the filler that is on the same plane as the resin layer and the depth of the concave part is 10% or more") is locally concentrated in the area, even if the performance of the filler-containing film Or there is no problem with the quality, and the appearance may be damaged. Moreover, when the concave parts 2b and 2c of such a region are directed toward the article and the filler-containing film is attached to the article, the concave parts 2b and 2c may swell after lamination. For example, when the filler-containing film is an anisotropic conductive film, if the conductive particles that are on the same plane as the insulating resin layer 2 and have a depth of 10% or more of the concave portion are concentrated in one bump, they will be generated after connecting with the bump. Bulging may cause a decrease in conductivity. Therefore, the number of fillers that are on the same plane as the resin layer and the depth of the concave portion is 10% or more in the area from any filler that is on the same plane as the resin layer 2 and has a depth of 10% or more of the concave part to within 200 times the particle size of the filler The ratio to the total number of fillers is preferably within 50%, more preferably within 40%, and still more preferably within 30%. On the other hand, in the area|region where this ratio exceeds 50%, it is preferable to spread resin etc. on the surface of a filler containing film, and to make the recessed parts 2b and 2c shallow. In this case, the viscosity of the resin to be dispersed is preferably lower than that of the resin forming the resin layer 2, and the concentration of the resin to be dispersed is preferably diluted to such an extent that the concave portion of the resin layer 2 can be recognized after the dispersion. By making the recessed parts 2b and 2c shallow in this way, the above-mentioned problems of appearance and bulging can be improved.

Furthermore, as shown in FIG. 7 , in the filler-containing film 10G in which the burial rate (Lb/D) is less than 60%, the filler 1 is easily rolled on the resin layer 2 , so that the object-to-filler ratio is improved when it is crimped to the article. In terms of the capture rate, it is preferable to set the burying rate (Lb/D) to 60% or more.

In addition, in a state where the burying ratio (Lb/D) exceeds 100%, like the filler-containing film 10X shown in FIG. 8, when the surface of the resin layer 2 is flat, the filler 1 and the article are interposed between The amount of resin in between becomes excessive. Also, like the filler-containing film 10Y shown in FIG. 9 , when the surface of the resin layer 2 is raised along the shape of the filler 1 , the filler 1 tends to flow due to the resin flow of the resin layer 2 when it is pressed against the article. Furthermore, since the filler 1 does not directly contact the article and presses the article, but presses the article through the resin, the filler also easily flows due to the resin flow.

In the present invention, the presence of the concave portions 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 by surface field observation. The concave portions 2b and 2c can also be observed with an optical microscope or a metal microscope. In addition, the size of the concave portions 2b and 2c can also be confirmed by focusing adjustment or the like at the time of image observation. The same is true even after resin is applied to the deep recessed portion as described above.

＜Variation of filler-containing film＞ (Second insulating resin layer) The filler-containing film of the present invention can also be like the filler-containing film 10H shown in FIG. 10 , in the surface of the resin layer 2 of the filler dispersion layer 3 where the concave portion 2 b is formed, the minimum melt viscosity of the laminate is preferably lower than that of the resin layer 2 . the second resin layer 4 . The second resin layer and the third resin layer described later are layers that do not contain the filler 1 dispersed in the filler-dispersed layer. In addition, as in the filler-containing film 10I shown in FIG. 11 , on the surface of the resin layer 2 of the filler-dispersed layer 3 on which the recesses 2b are not formed (the surface on the opposite side from the surface where the recesses are formed), the lowest melt viscosity may be laminated. The second resin layer 4 is lower than the resin layer 2 .

The second resin layer 4 may be insulating or conductive according to the application of the filler-containing film. By laminating the second resin layer 4, even if the surface of the article has irregularities, the space formed by the irregularities can be filled with the second resin layer when the filler-containing film is crimped to the article. Therefore, when the filler-containing film is used as an anisotropic conductive film having an insulating resin layer as the second resin layer, when the anisotropic conductive film is used to perform anisotropic conductive connection to the electronic components facing, The space formed by the electrodes or bumps of the electronic components can be filled with the second resin layer to improve the adhesion of the electronic components to each other.

Furthermore, when the anisotropic conductive film having the second resin layer 4 is used to anisotropically conductively connect the opposing electronic components, it is preferable whether or not the second resin layer 4 is located on the surface of the concave portion 2b. , the second resin layer 4 is located on the side of the first electronic component such as an IC chip (in other words, the resin layer 2 is located on the side of the second electronic component such as a substrate). In this way, the unexpected movement of the conductive particles can be avoided, and the catchability can be improved. In addition, generally, the first electronic component such as an IC chip is placed on the pressing jig side, the second electronic component such as a substrate is placed on the stage side, and the anisotropic conductive film and the second electronic component are preliminarily crimped, and then the first electronic component is placed on the platen side. The electronic component and the second electronic component are formally crimped, but according to the size of the crimping area of the second electronic component, after temporarily attaching the anisotropic conductive film to the first electronic component, the first electronic component and the second electronic component are bonded together. Parts are officially crimped.

The more the minimum melt viscosity of the resin layer 2 and the second resin layer 4 is different, the easier it is to fill the "space formed by the surface irregularities of the article containing the filler film by thermocompression" with the second resin layer. The adhesion of the film to the article, or the adhesion of the opposite articles to each other is improved when the article is thermocompressed via the filler-containing film. Furthermore, as the difference exists, the amount of movement of the resin layer 2 present in the filler dispersion layer 3 becomes relatively small relative to the second resin layer 4, and unnecessary flow of the filler held in the resin layer 2 can be reduced. Therefore, when the filler-containing film is used as an anisotropic conductive film of the second resin layer having insulating properties, the electrodes or bumps of electronic components for anisotropic conductive connection using the anisotropic conductive film are used. The formed space is easily filled with the second resin layer 4, and the effect of improving the adhesion between electronic components can be expected. In addition, since the amount of movement of the resin layer 2 holding the conductive particles in the filler-dispersed layer 3 is relatively small relative to the second resin layer, it is easy to improve the captureability of the conductive particles of the terminal.

The minimum melt viscosity ratio of the resin layer 2 and the second resin layer 4 also depends on the ratio of the layer thicknesses of the resin layer 2 and the second resin layer 4. In practical applications, it is preferably 2 or more, more preferably 5 or more, and then Preferably it is 8 or more. On the other hand, if the ratio is too large, when the long filler-containing film is made into a roll, there is a possibility that the resin will overflow or agglomerate. Therefore, in practical applications, the resin layer 2 and the second The minimum melt viscosity of the resin layer 4 is preferably 15 or less. More specifically, the preferred minimum melt viscosity of the second resin layer 4 satisfies the above ratio, and is 3000 Pa∙s or less, more preferably 2000 Pa∙s or less, especially 100 to 2000 Pa∙s.

Furthermore, the second resin layer 4 can be formed by adjusting the viscosity of the same resin composition as the resin layer 2 .

In addition, the thickness of the second resin layer 4 can be appropriately set according to the application of the filler-containing film. In general, it is preferable to set it as 0.2 to 50 times the particle size of the filler so as not to increase the difficulty of the lamination step of the second resin layer 4 excessively. When the filler-containing film is used as the anisotropic conductive films 10H and 10I, the layer thickness of the second resin layer 4 is preferably 4 to 20 μm, and is preferably 1 to 8 of the diameter of the conductive particles times.

In addition, in the anisotropic conductive films 10H and 10I, the minimum melt viscosity of the entire anisotropic conductive film obtained by aligning the insulating resin layer 2 and the second resin layer 4 also depends on the resin layer 2 and the second resin layer 4. In practical applications, the ratio of the thickness of the resin layer 4 can be set to be less than 8000 Pa∙s, and in order to facilitate filling between bumps, it can be 200 to 7000 Pa∙s, preferably 200 to 4000 Pa∙s .

(3rd resin layer) The third resin layer may be provided on the opposite side to the second resin layer 4 via the resin layer 2 . The third resin layer may be insulating or conductive according to the application of the filler-containing film. For example, when the filler-containing film is used as the anisotropic conductive film of the insulating third resin layer, the third resin layer can function as an adhesive layer. The 3rd resin layer may be provided in order to fill the space formed by the electrode of an electronic component or a bump similarly to a 2nd resin layer.

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 obtained by aligning the resin layer 2, the second resin layer 4 and the third resin layer is not particularly limited. It can also be set to 200 to 4000 Pa∙s.

(Other laminated versions) Depending on the application of the filler-containing film, a filler-dispersed layer may be laminated, a layer without filler such as a second resin layer may be interposed between the laminated filler-dispersed layers, or a second resin layer or a third resin layer may be further provided on the outermost layer. .

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

Among them, in the step of pressing the filler into the resin layer, the surface of the resin layer near the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between the adjacent fillers, and the pressure when the filler is pressed is adjusted. The viscosity of the resin layer, the pressing speed or the temperature.

The resin layer into which the filler is pressed is not particularly limited as long as the concave portions 2b and 2c described above can be formed. Among them, the minimum melt viscosity is preferably 1500 Pa∙s or more, more preferably 2000 Pa∙s or more, more preferably 3000 to 15000 Pa∙s, particularly preferably 3000 to 10000 Pa∙s, and the lower limit of the viscosity at 60°C Preferably, it is 3000 Pa∙s or more, more preferably 4000 Pa∙s or more, still 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 still more preferably 10000 Pa∙s or less. Therefore, it is preferable to make the minimum melt viscosity of the resin layer which hold|maintain a filler on the surface into the said range.

In the case where the filler-containing film is formed of a single layer of the filler-dispersed layer 3, the filler-containing film of the present invention is, for example, by holding the filler 1 on the surface of the resin layer 2 in a specific arrangement, and using a flat plate or a roller to hold the filler 1 on the surface of the resin layer 2. It is manufactured by pressing into the resin layer. Furthermore, in the case of manufacturing a filler-containing film with an embedding rate exceeding 100%, it is also possible to press-fit using a press plate having convex portions corresponding to the filler arrangement.

Here, the filling amount of the filler 1 in the resin layer 2 can be adjusted by the pressing force, temperature, etc. when the filler 1 is pressed, and the shape and depth of the recesses 2b and 2c can be adjusted by the resin layer when pressed 2. Adjust the viscosity, pressing speed, temperature, etc. For example, in the case of manufacturing the anisotropic conductive film 10B ( FIG. 2 ) as a filler-containing film, it is preferable to set the viscosity of the insulating resin layer 2 when the conductive particles 1 are pressed into 8000 Pa·s (60° C.), In the case of manufacturing the anisotropic conductive film 10C ( FIG. 3A ), it is preferable to set the viscosity of the insulating resin layer 2 when the conductive particles 1 are pressed into 12,000 Pa·s (70° C.), so that the anisotropic conductive film 10C ( FIG. 3A ) is manufactured. In the case of the conductive film 10D ( FIG. 4 ), it is preferable to set the viscosity of the insulating resin layer 2 when the conductive particles 1 are pressed into 4500 Pa·s (60° C.) to manufacture the anisotropic conductive film 10E ( FIG. 4 ). In the case of 5), it is preferable to set the viscosity of the insulating resin layer 2 when the conductive particles 1 are pressed into 7000 Pa·s (70° C.), in the case of producing the anisotropic conductive film 10F ( FIG. 6 ) , it is preferable to set the viscosity of the insulating resin layer 2 when the conductive particles 1 are pressed into 3500 Pa·s (70° C.).

In addition, as a method of holding the filler 1 in the resin layer 2, a well-known method can be utilized. For example, by directly dispersing the filler 1 on the resin layer 2, or by attaching the filler 1 in a single layer to a biaxially stretchable film, carrying out biaxial stretching of the film, and pressing the resin layer 2 on the stretched film to transfer the filler to The resin layer 2 holds the filler 1 in the resin layer 2 . Moreover, you may hold|maintain the filler 1 in the resin layer 2 using a transfer mold.

When a transfer mold is used to hold the filler 1 in the resin layer 2, as the transfer mold, for example, inorganic materials such as metals such as silicon, various ceramics, glass, and stainless steel, or organic materials such as various resins can be used. Those with openings formed by a known opening forming method such as photolithography", those using a printing method. In addition, the transfer mold may take a shape such as a plate shape and a roll shape. In addition, this invention is not limited to the said method.

In addition, the viscosity of the second resin layer 4 of the resin layer 2 may be lower than that of the surface on the side where the filler is pressed into the resin layer 2 or the opposite area thereof.

In the case of crimping a filled film to an article, or using a filled film to crimp an opposing article, in order to perform the crimping economically, the filled film is preferably elongated to some extent. Therefore, the length of the filler-containing film is preferably 5 m or more, more preferably 10 m or more, and still more preferably 25 m or more. On the other hand, if the filler-containing film is too long, in the case of crimping the filler-containing film and the article, the previous connecting device cannot be used, and the operability is also poor. Therefore, the length of the filler-containing film is preferably 5000 m or less, more preferably 1000 m or less, and still more preferably 500 m or less. In terms of excellent handleability, it is preferable that such a long body of the filler-containing film is a package that is wound into a core.

<How to use the filler film> The filler-containing film of the present invention can be used by being attached to an article in the same manner as the 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 corresponding to the use of the filler-containing film by crimping, preferably by thermocompression. When performing this bonding, light irradiation may be used, and heat and light may be used together. For example, when the resin layer of the filler-containing film has sufficient adhesion to the article to which the filler-containing film is attached, the filler-containing film can be adhered by gently pressing the resin layer of the filler-containing film against the article. A film bonded body formed on the surface of an article. In this case, the surface of the article is not limited to a flat surface, and may have concavities and convexities, or may be curved as a whole. When the article is in the form of a film or a flat plate, a crimping roller can also be used to attach the filler-containing film to the article. Thereby, the filler of the filler-containing film can also be directly bonded to the article.

In addition, the filler-containing film may be interposed between the opposing first and second items, and the two opposing items may be joined by a thermocompression-bonding roller or a crimping tool, and the filler may be sandwiched between the items. between. In addition, the filler-containing film may be sandwiched by the article so that the filler and the article are not brought into direct contact with each other.

In particular, when the filler-containing film is used as an anisotropic conductive film, it can be preferably used in the following situations, that is, using a thermocompression bonding tool, through the anisotropic conductive film, IC chips, IC modules, A first electronic component such as an FPC is anisotropically conductively connected to a second electronic component such as an FPC, glass substrate, plastic substrate, rigid substrate, and ceramic substrate. IC chips or wafers can also be stacked using anisotropic conductive films to be multi-layered. Furthermore, the electronic components connected by the anisotropic conductive film of the present invention are not limited to the above-mentioned electronic components. In recent years, it can be used for a variety of electronic parts.

Therefore, the present invention includes a bonded body obtained by bonding the filler-containing film of the present invention to various articles by crimping, or a manufacturing method of the bonded body. In particular, when the filler-containing film is used as an anisotropic conductive film, the method for producing a connection structure for anisotropically conductively connecting electronic components to each other using the anisotropic conductive film, or a method obtained therefrom is also included. The connection structure is a connection structure formed by anisotropically conductively connecting electronic components to each other by the anisotropic conductive film of the present invention.

As a method of connecting electronic components using an anisotropic conductive film, when the anisotropic conductive film is constituted by a single layer of the conductive particle dispersion layer 3, it can be produced by a self-isotropic conductive film The side with the conductive particles 1 embedded in the surface is temporarily bonded to second electronic components such as various substrates and pre-bonded, and the first electronic components such as IC chips are aligned with the pre-bonded anisotropic conductive film on the surface. The side where the conductive particles 1 are not embedded is thermocompressed. 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 (which may be the same as the thermal polymerizable compound) , can also be a combination of light and heat crimping method. In this way, the unexpected movement of the conductive particles can be suppressed to a minimum. Moreover, it can also be used by temporarily sticking the side on which the conductive particles are not embedded to the second electronic component. Furthermore, the anisotropic conductive film may be temporarily bonded to the first electronic component instead of the second electronic component.

Furthermore, 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 may be temporarily attached to the second electronic components such as various substrates and Preliminary crimping is performed, and the first electronic components such as an IC chip are placed on the side of the second insulating resin layer 4 of the preliminarily crimped anisotropic conductive film, and thermocompression bonding is performed. The second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component. In addition, the conductive particle-dispersed layer 3 side may be temporarily attached to the first electronic component and used. Example

Hereinafter, the anisotropic conductive film which is one aspect of the filler-containing film of the present invention will be specifically described by way of examples. Examples 1 to 15, Comparative Examples 1 to 3 (1) Manufacture of anisotropic conductive film With the compositions shown in Table 1A and Table 1B, resin compositions for forming the insulating resin layer, the second insulating resin layer, and the adhesive layer were prepared, respectively.

The resin composition for forming an insulating resin layer was coated on a PET film with a film thickness of 50 μm using a bar coater, dried in an oven at 80°C for 5 minutes, and formed on the PET film as shown in Table 2A and Table 2B. thickness of insulating resin layer. In the same manner, the second insulating resin layer and the adhesive 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 in which the conductive particles were randomly dispersed in a single layer (number density: 70,000/mm ² ).

[Table 1A] (unit: parts by mass) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 insulating resin layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 40 40 40 25 40 35 40 40 35 Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) 25 25 25 25 20 15 10 15 15 10 Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 30 30 30 30 15 40 15 40 40 15 Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 2 2 2 2 2 2 2 2 2 Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3 3 3 3 - 3 - 3 3 - Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - 38 - 38 - - 38 second insulating resin layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 40 40 40 30 - - - - - Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) 5 5 5 5 5 - - - - - Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 50 50 50 50 25 - - - - - Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 2 2 2 2 - - - - - Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3 3 3 3 - - - - - - Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - 38 - - - - - sticky layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) - - - - - - - - - - Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) - - - - - - - - - - Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) - - - - - - - - - - Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) - - - - - - - - - - Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) - - - - - - - - - - Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - - - - - - -

[Table 1B] (unit: parts by mass) Example 11 Example 12 Example 13 Example 14 Example 15 Comparative Example 1 Comparative Example 2 Comparative Example 3 insulating resin layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 35 40 40 40 40 40 40 Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) 10 30 25 15 25 25 15 25 Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 45 30 30 40 30 30 40 30 Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 2 2 2 2 2 2 2 Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3 3 3 3 3 3 3 3 Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - - - - - second insulating resin layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 40 40 - 40 40 - 40 Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) 5 5 5 - 5 5 - 5 Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 50 50 50 - 50 50 - 50 Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 2 2 - 2 2 - 2 Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3 3 3 - 3 3 - 3 Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - - - - - sticky layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) - - - - 37 - - - Silica filler (Nippon AEROSIL Co., Ltd., AEROSIL R805) - - - - 8 - - - Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) - - - - 50 - - - Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) - - - - 2 - - - Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) - - - - 3 - - - Microencapsulated latent hardener (ASAHI KASEI E-materials Co., Ltd. Novacure HX3941HP) - - - - - - - -

On the other hand, the conductive particles 1 are arranged in a square grid as shown in FIG. 1A in a plan view, the distance between particles is equal to the particle size of the conductive particles, and the number density of the conductive particles is 28000/ ^mm2 . That is, the following molds were fabricated: the pattern of the convex parts of the mold was arranged in a square lattice, the distance between the convex parts of the lattice axis was twice the diameter of the average conductive particle (3 μm), the lattice axis and the short side direction of the anisotropic conductive film. The angle θ formed was 15°, and particles of a known transparent resin were poured into the mold in a molten state, and cooled and solidified, thereby forming a resin mold with the concave portion having the arrangement pattern shown in FIG. 1A .

As the conductive particles, prepared in accordance with the description of Japanese Patent Application Laid-Open No. 2014-132567, in which insulating fine particles (average particle size: 0.3 μm) were adhered to metal-coated resin particles (Sekisui Chemical Industry Co., Ltd., AUL703, average particle size: 3 μm) were prepared. On the surface, the conductive particles were filled into the concave portion of the resin mold, the insulating resin layer described above was covered thereon, and it was bonded by pressing at 60° C. at 0.5 MPa. Next, the insulating resin layer was peeled off from the mold, and the conductive particles on the insulating resin layer were pressed into the insulating resin layer by pressing (pressing conditions: 60 to 70° C., 0.5 MPa) to prepare a dispersion of conductive particles. Anisotropic conductive film composed of a single layer of layers (Examples 6 to 10, 14 and Comparative Example 2). The embedded state of the conductive particles is controlled by pressing conditions.

Furthermore, a double-layer anisotropic conductive film was produced by laminating the second insulating resin layer by the conductive particle dispersion layer produced in the same manner (Examples 1 to 5, 11 to 13, and Comparative Example 1). Moreover, in the comparative example 3, as mentioned above, the 2nd insulating resin layer was laminated|stacked on the insulating resin layer in which the electroconductive particle was disperse|distributed. In this case, as shown in Table 2, the surface of the conductive particle-dispersed layer on which the second insulating resin layer was laminated was set to the surface of the insulating resin layer in which the conductive particles were pressed, or the surface on the opposite side.

Furthermore, a three-layer type anisotropic conductive film was produced by laminating an adhesive layer from the two-layer type anisotropic conductive film produced in the same manner (Example 15).

(2) Buried state The anisotropic conductive films of each of Examples 1 to 15 and Comparative Examples 1 to 3 were cut by a cutting line passing through the conductive particles, and the cross-sections were observed with a metal microscope. Moreover, with respect to Examples 4 to 10, 14 and Comparative Example 2 in which the conductive particles were exposed on the surface of the anisotropic conductive film, or the conductive particles were located near the film surface of the anisotropic conductive film, the surface of the film was examined by a metal microscope. Observed. 12A shows a sectional photograph of Example 2, FIG. 12B shows a sectional photograph of Example 3, FIG. 12C shows a sectional photograph of Comparative Example 3, FIG. 13A shows a photograph of the top surface of Example 4, and FIG. 13B shows the top surface photograph of Example 8 photo.

In Examples 1 to 7, 9 to 15, and Comparative Example 1, the conductive particles with an embedded rate of less than 60% and the conductive particles with an embedded rate of more than 100% were exposed from the insulating resin layer. Among them, in Example 1 In -7, 9-15, the recessed part 2b was observed in the surface of the insulating resin layer around the conductive particle (FIG. 12A, FIG. 12B, FIG. 13A). In Comparative Example 3, the burying rate was less than 100%, but the conductive particles were not exposed from the insulating resin layer, and the concave portions 2b and 2c were not observed. 12A , 12B and 12C, the metal layer 1p of the conductive particles 1 has a round shape with a darker color, and the insulating particle layer 1q attached to the metal layer 1p has a lighter color.

In Example 8, the conductive particles were completely embedded in the insulating resin layer, and the conductive particles were not exposed from the insulating resin layer, but concave portions 2c were observed on the surface of the insulating resin layer just above the conductive particle layer ( FIG. 13B ). In Comparative Example 2, the burial rate was slightly greater than 100%, the conductive particles were not exposed from the resin layer, the surface of the resin layer was flat, and no concave portion was observed on the surface of the resin layer directly above the conductive particles.

(3) Evaluation For the anisotropic conductive films of Examples and Comparative Examples produced in (1), the following methods were used to measure (a) initial on-resistance, (b) on-reliability, (c) particle trapping properties, and (d) positional deviation Move to measure or evaluate. The results are shown in Table 2A and Table 2B.

(a) Initial on-resistance The anisotropic conductive films of the Examples and Comparative Examples were cut with an area sufficient for connection, sandwiched between the IC for evaluation of conduction characteristics and the glass substrate, and heated and pressurized (180°C, 60 MPa, 5 seconds) ) to obtain each connector for evaluation, and measure the on-resistance of the connector for evaluation obtained by the four-terminal method. The initial on-resistance is preferably 2 Ω or less in practical applications, more preferably 0.6 Ω or less.

Here, the IC for evaluation corresponds to the terminal pattern of the glass substrate and the like, and the dimensions are as follows. Moreover, when connecting the IC for evaluation and a glass substrate, the long-side direction of an anisotropic conductive film and the short-side direction of a bump were aligned.

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

Glass substrate (ITO wiring) Glass Material Corning 1737F Outline 30×50mm Thickness 0.5 mm Electrode ITO wiring

(b) Turn-on reliability In the same manner as the initial on-resistance, the on-resistance after leaving the connector for evaluation prepared in (a) in a thermostatic bath with a temperature of 85° C. and a humidity of 85% RH for 500 hours was measured. In practical applications, the on-reliability is preferably 6 Ω or less, more preferably 4 Ω or less.

(c) Particle capture Using the IC for evaluation of particle trapping properties, the IC for evaluation was aligned with the glass substrate (ITO wiring) corresponding to the terminal pattern at a distance of 6 μm, and heat and pressure were applied (180°C, 60 MPa, 5 seconds) to evaluate The number of trapped conductive particles was measured in 100 regions of 6 μm × 66.6 μm where the bumps of the IC and the terminals of the substrate overlapped, and the minimum trapped number was obtained, and evaluated according to the following criteria. In practical use, the B evaluation or more is preferable.

IC for evaluation of particle capture performance Outline 1.6×29.8 mm Thickness 0.3 mm Bump size 12×66.6 μm, bump pitch 22 μm (L/S=12 μm/10 μm), bump height 12 μm

Particle Capture Performance Evaluation Criteria A 5 or more B More than 3 and less than 5 C less than 3

(d) Position offset Using the same evaluation IC as in (c), the evaluation IC and the glass substrate (ITO wiring) corresponding to the terminal pattern were aligned and heated and pressurized (180° C., 60 MPa, 5 seconds). In this case, the inter-particle distance before heating and pressing and the inter-particle distance after heating and pressing (measured by observation of the indentation from the glass side) were measured with a metal microscope, and the average value of each was obtained and calculated by the following formula The particle gap was evaluated according to the following criteria. In practical use, the C evaluation or higher is preferable.

In addition, in Comparative Example 3, since the conductive particles were randomly dispersed, the evaluation of positional displacement was not performed.

Particle gap = 100*P1/P0 (In the formula, P1: the average value of particle spacing after heating and pressing, P0: Average value of particle spacing before heating and pressing)

Position Offset Evaluation Criteria A Particle gap below 160% B Particle gap exceeds 160% and is less than 180% C Particle gap exceeds 180% and is less than 200% D Particle gap exceeds 200%

凹部2b、2c之有無 有凹部2b 有凹部2b 有凹部2b 有凹部2b 有凹部2b 有凹部2b 有凹部2b 導電粒子完全埋入至絕緣性樹脂層中，有凹部2c 有凹部2b 有凹部2b 導電粒子之直徑：D（μm） 3 3 3 3 3 3 3 3 3 3 埋入率：100×Lb／D（%） 63 87 100 100 103 103 103 105 103 103 粒子露出直徑：Lc（μm） 3 3 3 2.2 2.3 2.4 2.4 0 2.4 2.4 埋入量：Lb（μm） 1.9 2.6 3 3.0 3.1 3.1 3.1 3.2 3.1 3.1 導電粒子存在位置上之膜最小厚度：Ld（μm） 2.1 1.4 1.0 1.0 0.9 14.9 14.9 14.8 14.9 14.9 厚度（μm） 黏性層 － － － － － － － － － － 絕緣性樹脂層（La） 4 4 4 4 4 18 18 18 30 30 第2絕緣性樹脂層 14 14 14 14 14 － － － － － La／D 1.3 1.3 1.3 1.3 1.3 6 6 6 10 10 最低熔融黏度（Pα∙s） 黏性層 － － － － － － － － － － 絕緣性樹脂層 6000 6000 6000 6000 6000 3000 3000 3000 3000 3000 第2絕緣性樹脂層 800 800 800 800 800 － － － － － 絕緣性樹脂層／第2絕緣性樹脂層 8 8 8 8 8 － － － － － 60℃黏度（Pa∙s） 絕緣性樹脂層 8000 8000 8000 8000 8000 4500 4500 4500 4500 4500 導通特性（Ω） 初期導通電阻 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 導通可靠性500 hr 2.5 2.2 2.2 2.4 2.3 2.4 2.4 2.3 2.8 2.7 粒子捕捉性 B A A A A B B B B B 位置偏移 B A A A A B B B B B [Table 2A] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 particle position

Presence of recesses 2b, 2c With recess 2b With recess 2b With recess 2b With recess 2b With recess 2b With recess 2b With recess 2b The conductive particles are completely embedded in the insulating resin layer, and there are recesses 2c With recess 2b With recess 2b Diameter of conductive particles: D (μm) 3 3 3 3 3 3 3 3 3 3 Burial rate: 100×Lb/D (%) 63 87 100 100 103 103 103 105 103 103 Particle exposure diameter: Lc (μm) 3 3 3 2.2 2.3 2.4 2.4 0 2.4 2.4 Buried amount: Lb (μm) 1.9 2.6 3 3.0 3.1 3.1 3.1 3.2 3.1 3.1 The minimum thickness of the film where the conductive particles exist: Ld (μm) 2.1 1.4 1.0 1.0 0.9 14.9 14.9 14.8 14.9 14.9 Thickness (μm) sticky layer - - - - - - - - - - Insulating resin layer (La) 4 4 4 4 4 18 18 18 30 30 second insulating resin layer 14 14 14 14 14 - - - - - La/D 1.3 1.3 1.3 1.3 1.3 6 6 6 10 10 Minimum melt viscosity (Pα∙s) sticky layer - - - - - - - - - - insulating resin layer 6000 6000 6000 6000 6000 3000 3000 3000 3000 3000 second insulating resin layer 800 800 800 800 800 - - - - - Insulating resin layer/Second insulating resin layer 8 8 8 8 8 - - - - - Viscosity at 60℃（Pa∙s） insulating resin layer 8000 8000 8000 8000 8000 4500 4500 4500 4500 4500 On characteristics (Ω) Initial on-resistance 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 On reliability 500 hr 2.5 2.2 2.2 2.4 2.3 2.4 2.4 2.3 2.8 2.7 particle capture B A A A A B B B B B position offset B A A A A B B B B B

凹部2b、2c之有無 有凹部2b 有凹部2b 有凹部2b 有凹部2b 有凹部2b 無凹部2b 導電粒子完全埋入至絕緣性樹脂層中，無凹部2c 無凹部2b、2c 導電粒子之直徑：D（μm） 3 3 3 3 3 3 3 3 埋入率：100×Lb／D（%） 103 100 43 103 60 64 ＞100 75 粒子露出直徑：Lc（μm） 3 3 2.6 2.3 2.6 2.5 0 0 埋入量：Lb（μm） 3.1 3.0 1.3 3.1 1.8 1.9 ＞3.0 2.2 導電粒子存在位置上之膜最小厚度：Ld（μm） 1.0 1.0 2.7 14.9 1.2 1.8 14.8 2.3 厚度（μm） 黏性層 － － － － 3 － － － 絕緣性樹脂層（La） 4 4 4 36 3 4 18 4 第2絕緣性樹脂層 14 14 14 － 12 14 － 14 La／D 1.3 1.3 1.3 12 1 1.3 6 1.3 最低熔融黏度（Pα∙s） 黏性層 － － － － 1000 － － － 絕緣性樹脂層 2000 10000 6000 3000 6000 1000 1000 6000 第2絕緣性樹脂層 800 800 800 － 800 800 － 800 絕緣性樹脂層／第2絕緣性樹脂層 3 13 8 － 8 1 － 8 60℃黏度（Pa∙s） 絕緣性樹脂層 3000 15000 8000 4500 8000 1500 1500 8000 導通特性（Ω） 初期導通電阻 0.2 0.2 0.2 0.4 0.2 0.2 0.2 0.3 導通可靠性500 hr 2.5 2.5 2.5 4.9 2.8 2.4 2.5 6.4 粒子捕捉性 B A B B B C C C 位置偏移 B A C C C D D － [Table 2B] Example 11 Example 12 Example 13 Example 14 Example 15 Comparative Example 1 Comparative Example 2 Comparative Example 3 particle position

Presence of recesses 2b, 2c With recess 2b With recess 2b With recess 2b With recess 2b With recess 2b Without recess 2b The conductive particles are completely embedded in the insulating resin layer, and there are no recesses 2c No recesses 2b, 2c Diameter of conductive particles: D (μm) 3 3 3 3 3 3 3 3 Burial rate: 100×Lb/D (%) 103 100 43 103 60 64 >100 75 Particle exposure diameter: Lc (μm) 3 3 2.6 2.3 2.6 2.5 0 0 Buried amount: Lb (μm) 3.1 3.0 1.3 3.1 1.8 1.9 >3.0 2.2 The minimum thickness of the film where the conductive particles exist: Ld (μm) 1.0 1.0 2.7 14.9 1.2 1.8 14.8 2.3 Thickness (μm) sticky layer - - - - 3 - - - Insulating resin layer (La) 4 4 4 36 3 4 18 4 second insulating resin layer 14 14 14 - 12 14 - 14 La/D 1.3 1.3 1.3 12 1 1.3 6 1.3 Minimum melt viscosity (Pα∙s) sticky layer - - - - 1000 - - - insulating resin layer 2000 10000 6000 3000 6000 1000 1000 6000 second insulating resin layer 800 800 800 - 800 800 - 800 Insulating resin layer/Second insulating resin layer 3 13 8 - 8 1 - 8 Viscosity at 60℃（Pa∙s） insulating resin layer 3000 15000 8000 4500 8000 1500 1500 8000 On characteristics (Ω) Initial on-resistance 0.2 0.2 0.2 0.4 0.2 0.2 0.2 0.3 On reliability 500 hr 2.5 2.5 2.5 4.9 2.8 2.4 2.5 6.4 particle capture B A B B B C C C position offset B A C C C D D -

From Table 2A and Table 2B, it can be seen that the embedded rate of conductive particles is between 60% and 105%, the conductive particles protrude from the insulating resin layer and have recesses 2b in Examples 1 to 3, or the conductive particles are completely embedded in the insulating resin layer. In Example 8, which has a conductive resin layer and has recesses 2c, the initial on-resistance and on-reliability are very low, and the evaluations of particle trapping properties and positional displacement are also good. Comparative example 1 in which the layer protrudes but no recess 2b and "Comparative example 2 in which the conductive particles are completely embedded in the insulating resin layer and no recess 2c", the positional displacement was evaluated as D, and the conductive particles could not be held during connection, so they could not cope with Micro-pitch connections. In addition, it can be seen that “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 there is neither a concave part 2b nor a recessed portion 2b in the vicinity of the conductive particles 1. The conduction reliability of the comparative example 3" without the concave portion 2c was poor. From this, it can be inferred that if 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 flow of the resin during anisotropic conductive connection, and the pressing of the conductive particles to the terminals is insufficient. .

In addition, it can be seen that the minimum melt viscosity of the insulating resin layers of the above-mentioned Examples 1 to 3 and 8 is 2000 Pa·s or more, the melt viscosity at 60°C is 3000 Pa·s or more, and the minimum melt viscosity of Comparative Examples 1 and 2 is 1000 Pa. ∙s, the melt viscosity at 60°C was 1500 Pa∙s, and since the viscosity at the time of pressing was lowered by adjusting the pressing conditions of the conductive particles, the concave portions 2b and 2c were not formed. On the other hand, the minimum melt viscosity or 60° C. viscosity of Comparative Example 3 was approximately the same as that of Examples 1 to 3, but the conductive particle dispersion layer was not formed by laminating conductive particles on an insulating resin, but by making Since the conductive particles are dispersed in the resin composition forming the insulating resin layer, and the conductive particles are coated to form the conductive particle dispersion layer, the concave portions 2b and 2c are not formed.

In addition, it can be seen that with respect to Example 3 (minimum melt viscosity 6000 Pa∙s, 60°C melt viscosity 8000 Pa∙s), no matter the conditions are as in Example 11 (minimum melt viscosity 2000 Pa∙s, 60°C melt viscosity 3000 Pa∙s) s), or as high as in Example 12 (minimum melt viscosity 10,000 Pa∙s, 60°C melt viscosity 15,000 Pa∙s), when concave portions 2b are formed around the conductive particles, All of the positional shifts were rated B or higher, and there was no problem in practical use.

Furthermore, it can be seen that the embedding ratio of the conductive particles of the above-mentioned Examples 1 to 3 and 8 is between 60 and 105%, and that the evaluation of the positional displacement of Example 13 in which the embedding ratio is lower than 60% is lower.

From Examples 4 and 5 and Examples 6 and 7, it can be seen that when the anisotropic conductive film is a double-layer type of the conductive particle-dispersed layer and the second insulating resin layer, the conductive particle-dispersed layer is a single layer. In this case, the evaluations of particle trapping properties and positional displacement are good in practical applications. In addition, it can be seen from Examples 2, 3, 13 and 15 that even if the two-layer type anisotropic conductive film is further provided with an adhesive layer to form a three-layer type, the particle trapping properties are good in practical use.

From Example 3 and Examples 4 and 5, it can be seen that when the anisotropic conductive film is made into a two-layer type of the conductive particle dispersion layer and the second insulating resin layer, the conductive particles are pressed into the insulating resin layer and conductive. In the case where the second insulating resin layer is layered on the area of the particles, and the case where the second insulating resin layer is layered on the opposite side, the evaluation of particle trapping properties and positional displacement is good in practice.

Furthermore, as can be seen from Examples 6, 7, 9, 10 and 14, the ratio La/D to the layer thickness La of the insulating resin layer and the particle diameter D of the conductive particles is 10 or less, and when it exceeds 10, the position The evaluation of the offset becomes lower.

Furthermore, the same resin composition diluted with the same resin composition was sprayed on the exposed surfaces of the conductive particles of the anisotropic conductive films of Examples 4 and 5 to make the surface substantially smooth. equivalent results.

In addition, in the same manner as the method for measuring the number of shorts described in the examples of Japanese Patent Laid-Open No. 2016-085983, the number of shorts between 100 bumps was confirmed for the connectors for evaluation of the initial on-resistance of all the examples. , resulting in no short-circuiters. Furthermore, with regard to the anisotropic conductive films of all the examples, the short-circuit occurrence rate was determined in accordance with the method for measuring the short-circuit occurrence rate described in the examples of JP-A No. 2016-085982, and the results were found to be less than 50 ppm. There is no problem in practical application.

Experimental examples 1 to 4 (Fabrication of anisotropic conductive film) In order to study the effect of the resin composition of the insulating resin layer on the film forming ability and conduction characteristics of the anisotropic conductive film used for COG connection, the insulating resin layer and the second insulating resin were prepared with the compositions shown in Table 3. layer of resin composition. In this case, the minimum melt viscosity of the resin composition is adjusted by the preparation conditions of the resin composition. Using the obtained resin composition, an insulating resin layer was formed in the same manner as in Example 1, and an anisotropic conductive layer composed of a single layer of a conductive particle dispersion layer was produced by laminating the insulating resin into conductive particles. Then, a second insulating resin layer was laminated on the side of the insulating resin layer where the conductive particles were pressed into the insulating resin layer to produce the anisotropic conductive film shown in Table 4. In this case, the configuration of the conductive particles is the same as that of the first embodiment. In addition, by appropriately adjusting the pressing conditions of the conductive particles, the conductive particles were in the embedded state shown in Table 4.

In the production process of the anisotropic conductive film, after the insulating resin was laminated with the conductive particles, the film shape was not maintained in Experimental Example 4 (film shape evaluation: NG), but was maintained in the other experimental examples. Film shape (film shape evaluation: OK). Therefore, the embedded state of the conductive particles was observed and measured with a metal microscope in the anisotropic conductive films of the experimental examples other than the experimental example 4, and the subsequent evaluation was performed.

Furthermore, in each of the experimental examples other than Experimental Example 4, the concave portions around the conductive particles exposed from the insulating resin layer, the concave portions in the insulating resin layer directly above the conductive particles, or both were observed. Table 4 shows the measurement values of those in which the recesses were most clearly observed in each of the experimental examples. The observed buried state satisfies the above-mentioned preferred range.

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

[Table 4] Experimental example 1 Experimental example 2 Experimental example 3 Experimental example 4 Composition of resin composition (Table 3) A B C D Film shape after pressing conductive particles OK OK OK NG Diameter of conductive particles: D (μm) 3 3 3 3 Configuration of Conductive Particles square lattice square lattice square lattice square lattice The distance between the centers of the nearest conductive particles (μm) 6 6 6 6 Thickness (μm) Insulating resin layer (La) 4 4 4 4 second insulating resin layer 14 14 14 14 La/D 1.3 1.3 1.3 1.3 Minimum melt viscosity (Pα∙s) insulating resin layer 8000 2000 1500 800 second insulating resin layer 800 800 800 800 total melt viscosity 1200 900 900 800 Viscosity at 60℃（Pa∙s） insulating resin layer 12000 3000 2000 1100 Buried state of conductive particles Buried rate (100×Lb/D)% >80 >95 >95 - Exposed diameter: Lc (μm) <2.8 <2.5 <2.5 - The presence or absence of recesses Have Have Have - The maximum depth Le of the concave part (ratio to the diameter D of the conductive particle) <50% <50% <50% - The maximum diameter Ld of the concave portion (ratio to the diameter D of the conductive particle) <1.3 <1.3 <1.3 - Evaluation Initial on-resistance 0K OK OK - turn-on reliability OK OK OK -

(Evaluation) (a) Initial on-resistance and on-reliability The initial on-resistance and on-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 on-resistance OK: 2.0 Ω or less NG: greater than 2.0 Ω

Evaluation Criteria for On-Reliability OK: 6.0 Ω or less NG: greater than 6.0 Ω

(b) Particle capture The particle capturing properties were evaluated in the same manner as in Example 1. As a result, all of Experimental Examples 1 to 3 were above the B judgment.

(c) Short circuit occurrence rate The short-circuit occurrence rate was evaluated in the same manner as in Example 1. As a result, none of Experimental Examples 1 to 3 reached 50 ppm, and it was confirmed that there was no problem in practical use.

As can be seen from Table 4, when the minimum melt viscosity of the insulating resin layer is 800 Pa·s, it is difficult to form a film having a concave portion in the insulating resin layer in the vicinity of the conductive particles. On the other hand, it was found that if the minimum melt viscosity of the insulating resin layer is 1500 Pa·s or more, the recesses can be formed on the surface of the insulating resin layer in the vicinity of the conductive particles by adjusting the conditions for burying the conductive particles. The anisotropic conductive film has good conduction characteristics in COG applications. In addition, in all of the experimental examples 1 to 3, the initial on-resistance was 0.6 Ω or less, and the on-reliability was 4 Ω or less, showing good results.

Experimental Examples 5 to 8 (Fabrication of anisotropic conductive film) In order to investigate the effect of the resin composition of the insulating resin layer on the film forming ability and conduction characteristics of the anisotropic conductive film used for FOG connection, the results are shown in Table 5. Composition The resin composition for forming the insulating resin layer and the second insulating resin layer was prepared. In this case, the conductive particles were arranged in a hexagonal lattice arrangement with a number density of 15,000 particles/mm ² such that one of the lattice axes was inclined by 15° with respect to the longitudinal direction of the anisotropic conductive film. Moreover, the minimum melt viscosity of a resin composition is adjusted by the preparation conditions of a resin composition. Using the obtained resin composition, an insulating resin layer was formed in the same manner as in Example 1, and anisotropy composed of a single layer of a conductive particle-dispersed layer was produced by laminating conductive particles to the insulating resin. The conductive film was further laminated with a second insulating resin layer on the side of the insulating resin layer where the conductive particles were pressed to produce the 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 pressing conditions of the conductive particles.

In the production process of the anisotropic conductive film, after the conductive particles were laminated to the insulating resin, the film shape was not maintained in Experimental Example 8 (film shape evaluation: NG), but the film was maintained in the other experimental examples. Shape (film shape evaluation: OK). Therefore, the embedded state of the conductive particles was observed and measured with a metal microscope in the anisotropic conductive films of the experimental examples other than the experimental example 8, and the subsequent evaluation was performed.

Furthermore, in each of the experimental examples other than Experimental Example 8, the concave portions around the conductive particles exposed from the insulating resin layer, the concave portions in the insulating resin layer directly above the conductive particles, or both were observed. Table 6 shows the measured values of those in which the recesses were most clearly observed in each of the experimental examples. The observed buried state satisfies the above-mentioned preferred range.

[table 5] (parts by mass) composition E F G H insulating resin layer Phenoxy resin (YP-50, Nippon Steel & Sumitomo Metal Chemical) 55 45 25 5 Phenoxy resin (FX-316ATM55, Nippon Steel & Sumitomo Metal Chemical) 20 40 Difunctional Acrylate (A-DCP, Shin-Nakamura Chemical Industry) 20 20 20 20 Difunctional urethane acrylate oligomer (UN-9200A, Negami Industry) 25 35 35 35 Silane coupling agent (A-187, Momentive Performance Materials) 1 1 1 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku) 1 1 1 1 Benzyl peroxide (Nyper-BW, Nippon Oil) 5 5 5 5 second insulating resin layer Phenoxy resin (FX-316ATM55, Nippon Steel & Sumitomo Metal Chemical) 50 Difunctional Acrylate (A-DCP, Shin-Nakamura Chemical Industry) 20 Difunctional urethane acrylate oligomer (UN-9200A, Negami Industry) 30 Silane coupling agent (A-187, Momentive Performance Materials) 1 Phosphate methacrylate (KAYAMER PM-2, Nippon Kayaku) 1 Benzyl peroxide (Nyper-BW, Nippon Oil) 5

[Table 6] Experimental example 5 Experimental example 6 Experimental example 7 Experimental example 8 Composition of resin composition (Table 5) E F G H Film shape after pressing conductive particles OK OK OK NG Diameter of conductive particles: D (μm) 3 3 3 3 Configuration of Conductive Particles hexagonal lattice hexagonal lattice hexagonal lattice hexagonal lattice The distance between the centers of the nearest conductive particles (μm) 9 9 9 9 Thickness (μm) Insulating resin layer (La) 4 4 4 4 second insulating resin layer 14 14 14 14 La/D 1.3 1.3 1.3 1.3 Minimum melt viscosity (Pα∙s) insulating resin layer 8000 2000 1500 800 second insulating resin layer 800 800 800 800 total melt viscosity 1200 900 900 800 Viscosity at 60℃（Pa∙s） insulating resin layer 12000 3000 2000 1100 Buried state of conductive particles - Buried rate (100×Lb/D)% >80 >95 >95 - Exposed diameter: Lc (μm) <2.8 <2.5 <2.5 - The presence or absence of recesses Have Have Have - The maximum depth Le of the concave part (ratio to the diameter D of the conductive particle) <50% <50% <50% - The maximum diameter Ld of the concave portion (ratio to the diameter D of the conductive particle) <1.3 <1.3 <1.3 Evaluation Initial on-resistance OK OK OK - turn-on reliability OK OK OK -

(Evaluation) (a) Initial on-resistance and on-reliability (i) initial on-resistance and (ii) on-reliability were evaluated as follows. The results are shown in Table 6.

(i) Initial on-resistance The anisotropic conductive film obtained in each experimental example was cut in an area sufficient for connection, sandwiched between the FPC for evaluation of conduction characteristics and an alkali-free glass substrate, and heated with a tool width of 1.5 mm of a thermocompression bonding tool. Pressurization (180° C., 4.5 MPa, 5 seconds) was applied to obtain each connector for evaluation. The on-resistance of the obtained connector for evaluation was measured by the four-terminal method, and the measured value was evaluated according to the following criteria.

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

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

Evaluation criteria for initial on-resistance OK: less than 2.0 Ω NG: 2.0 Ω or more

(ii) On reliability The connector for evaluation prepared in (i) was left for 500 hours in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH, and the subsequent on-resistance was measured in the same manner as the initial on-resistance, and the measured value was evaluated according to the following criteria.

Evaluation Criteria for On-Reliability OK: less than 5.0 Ω NG: 5.0 Ω or more (b) Particle capture The number of trapped conductive particles was measured for 100 terminals of the connector for evaluation prepared in (i), and the minimum number of trapped was determined. If the minimum number of captures is 10 or more, there is no problem in practical application. The minimum capture numbers of Experimental Examples 5 to 7 were all 10 or more.

(c) Short circuit occurrence rate The number of short circuits in the evaluation connector produced in (i) was measured, and the short circuit occurrence rate was determined from the measured number of short circuits and the number of gaps in the evaluation connector. The short-circuit occurrence rates of Experimental Examples 5 to 7 were all less than 50 ppm, and it was confirmed that there was no problem in practical application.

As can be seen from Table 6, when the minimum melt viscosity of the insulating resin layer is 800 Pa·s, it is difficult to form a film having concave portions on the surface of the insulating resin layer near the conductive particles. On the other hand, it was found that if the minimum melt viscosity of the insulating resin layer is 1500 Pa·s or more, the recesses can be formed on the surface of the insulating resin layer in the vicinity of the conductive particles by adjusting the conditions for burying the conductive particles. The anisotropic conductive film has good conduction characteristics in FOG applications.

1: filler, conductive particles 1a: Top of stuffing 1p: Metal layer of conductive particles 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: filled film, anisotropic conductive film 20: Terminal A: Lattice axis D: Particle size of filler, particle size of conductive particles La: layer thickness of resin layer Lb: Buried amount (the distance between the deepest part of the packing and the tangent plane on the central part between the adjacent packings) Lc: exposed diameter Ld: Maximum diameter of the recess Le: The maximum depth of the concave portion around the exposed portion of the filler Lf: the maximum depth of the recess in the resin just above the filler θ: The angle formed by the longitudinal direction of the terminal and the grid axis of the arrangement of the conductive particles

1A is a plan view showing the arrangement of conductive particles in an anisotropic conductive film 10A of an example which is an aspect of the filler-containing film of the present invention. 1B is a cross-sectional view of an anisotropic conductive film 10A which is an example of an aspect of the filler-containing film of the present invention. [ Fig. 2 ] is a cross-sectional view of an anisotropic conductive film 10B which is an embodiment of the filler-containing film of the present invention. 3A is a cross-sectional view of an anisotropic conductive film 10C of an example which is an aspect of the filler-containing film of the present invention. 3B is a cross-sectional view of an anisotropic conductive film 10C' of an example which is an aspect of the filler-containing film of the present invention. [ Fig. 4] Fig. 4 is a cross-sectional view of an anisotropic conductive film 10D which is an embodiment of the filler-containing film of the present invention. [ Fig. 5] Fig. 5 is a cross-sectional view of an anisotropic conductive film 10E which is an embodiment of the filler-containing film of the present invention. 6] It is sectional drawing of the anisotropic conductive film 10F of the Example which is one aspect of the filler-containing film of this invention. [ Fig. 7] Fig. 7 is a cross-sectional view of an anisotropic conductive film 10G which is an embodiment of the filler-containing film of the present invention. 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. 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. 10 is a cross-sectional view of an anisotropic conductive film 10H which is an embodiment of the filler-containing film of the present invention. 11 is a cross-sectional view of an anisotropic conductive film 10I which is an embodiment of the filler-containing film of the present invention. 12A is a cross-sectional photograph of an anisotropic conductive film of an example which is an aspect of the filler-containing film of the present invention. 12B is a cross-sectional photograph of an anisotropic conductive film of an example, which is an aspect of the filler-containing film of the present invention. 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 ] It is a photograph of the upper surface of the anisotropic conductive film of an example which is an aspect of the filler-containing film of the present invention. [ Fig. 13B ] It is a photograph of the upper surface of the anisotropic conductive film of Example which is an aspect of the filler-containing film of the present invention.

1: filler, conductive particles

2: resin layer

2a: Surface of resin layer

2b: Recess

2p: tangent plane

3: Filler dispersion layer, conductive particle dispersion layer

10A: Filler film, anisotropic conductive film

D: Particle size of filler, particle size of conductive particles

La: layer thickness of resin layer

Lb: Buried amount (the distance between the deepest part of the packing and the tangent plane on the central part between the adjacent packings)

Lc: exposed diameter

Ld: Maximum diameter of recess

Le: The maximum depth of the concave portion around the exposed portion of the filler

Claims (27)

A filler-containing film having a filler-dispersed layer in which a filler is dispersed in a resin layer, and The surface of the resin layer in the vicinity of the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between the adjacent fillers. The filler-containing film of claim 1, wherein a concave portion is formed on the surface of the resin layer around the filler exposed from the resin layer. According to the filler-containing film of claim 2, the ratio (Le/D) of the depth Le of the concave portion from the tangential plane to the particle size D of the filler is less than 50%. The filler-containing film according to claim 2 or 3 of the claimed scope, wherein the ratio (Ld/D) of the maximum diameter Ld of the concave portion to the particle size D of the filler is 100% or more. The filler-containing film of claim 1, wherein the concave portion is formed on the surface of the resin layer just above the filler buried in the resin layer which is not exposed from the resin layer. The filler-containing film of claim 1, wherein the filler and the tangent plane of the resin layer on the central portion between the adjacent fillers are in contact, and a concave portion is formed on the surface of the resin layer around the contact. According to the filler-containing film of claim 5 or 6, the ratio (Lf/D) of the depth Lf of the recess from the tangential plane to the particle size D of the filler is less than 10%. The filler-containing film according to any one of items 1 to 7 of the claimed scope, wherein the ratio (La/D) of the layer thickness La of the resin layer to the particle size D of the filler is 0.6-10. The filler-containing film according to any one of claims 1 to 8, wherein the distance Lb between the deepest part of the filler and the tangent plane on the central part between the adjacent fillers on the surface of the resin layer on which the recesses are formed is equal to The ratio (Lb/D) of the particle size D of the filler is 60% or more and 105% or less. The filler-containing film according to any one of claims 1 to 9, wherein the fillers are arranged without contacting each other. The filler-containing film according to any one of the claims 1 to 10 of the claimed scope, wherein the distance between the closest particles of the filler is more than 0.5 times the particle size of the filler. The filler-containing film according to any one of claims 1 to 11, wherein the resin layer of the filler-dispersed layer has a second resin layer on the surface layer on the opposite side to the surface on which the recesses are formed. The filler-containing film according to any one of Claims 1 to 11, wherein a second resin layer is formed on the surface layer of the resin layer of the filler-dispersed layer on which the recesses are formed. The filler-containing film of 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 of the resin layer of the filler-dispersed layer and the second resin layer is 2 or more. The filler-containing film according to any one of items 1 to 15 of the patent application scope, wherein the viscosity of the resin layer of the filler-dispersed layer at 60°C is 3000-20000 Pa∙s. The filler-containing film according to any one of claims 1 to 16 of the claimed scope, wherein the filler is conductive particles, the resin layer of the filler-dispersed layer is an insulating resin layer, and is used as an anisotropic conductive film. A film adhered body, which adheres the filler-containing film of any one of items 1 to 17 of the patent application scope to an article. A connecting structure which connects a first article and a second article through the filler-containing film of any one of the claims 1 to 17 of the application scope. According to the connecting structure of claim 19, the first electronic part and the second electronic part are anisotropically conductively connected via the filler-containing film of claim 17. A method of manufacturing a connecting structure, which comprises crimping a first article and a second article through the filler-containing film of any one of the claims 1 to 17. According to the manufacturing method of the connecting structure of the claim 21, wherein, the first article and the second article are set as the first electronic component and the second electronic component, respectively, by the filler-containing filler according to the claim 17 The film thermally press-bonds the first electronic component and the second electronic component, and manufactures a connection structure in which the first electronic component and the second electronic component are connected by anisotropic conduction. A method for producing a filler-containing film, which has the step of forming a filler-dispersed layer in which a filler is dispersed in a resin layer, The step of forming the filler-dispersed layer includes the step of holding the filler on the surface of the resin layer, and The step of pressing the filler held on the surface of the resin layer into the resin layer, In the step of keeping the filler on the surface of the resin layer, the filler is kept on the surface of the resin layer in a state where the filler is dispersed, and In the step of pressing the filler into the resin layer, the resin layer when the filler is pressed is adjusted so that the surface of the resin layer near the filler has a concave portion with respect to the tangent plane of the resin layer on the central portion between the adjacent fillers viscosity, indentation speed or temperature. The method for producing a filler-containing film according to claim 23, wherein, in the step of keeping the filler on the surface of the resin layer, the minimum melt viscosity is 1100 Pa∙s or more and the viscosity at 60°C is 3000 Pa∙s The above resin layer serves as a resin layer. The method for producing a filler-containing film as claimed in claim 23 or 24, wherein, in the step of keeping the filler on the surface of the resin layer, the filler is kept on the surface of the resin layer in a specific arrangement, and In the step of pressing the filler into the resin layer, the filler is pressed into the resin layer using a flat plate or a roller. The method for producing a filler-containing film according to any one of claims 23 to 25, wherein, in the step of keeping the filler on the surface of the resin layer, the transfer mold is filled with the filler, and the filler is transferred It is printed on the resin layer to keep the filler on the surface of the resin layer in a specific configuration. The method for producing a filler-containing film according to any one of the claims 23 to 26 of the scope of the patent application, wherein conductive particles are used as fillers, an insulating resin layer is used as a resin layer of the filler-dispersed layer, and anisotropic conductive films are produced as filler-containing films membrane.

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