Filled film

Abstract

The filler-containing film has a structure that retains the filler in the adhesive resin layer. The average particle diameter of the filler is 1 to 50 μm, the total thickness of the resin layer is 0.5 times or more and 2 times or less of the average particle diameter of the filler, and the ratio (Lq / Lp) of the minimum distance between the fillers (Lq) at the other end of the long side of the film, which is 5 m or more from the one end, to the minimum distance between the fillers (Lp) at the one end is 1.2 or less. It is preferable that the fillers are arranged in a lattice shape.

Description

[0001] This application is a divisional application of the original patent application filed on November 20, 2017, with original application number 201780074602.3 (international application number PCT / JP2017 / 041681) and entitled "Membrane Containing Filler". Technical Field

[0002] This invention relates to membranes containing fillers. Background Technology

[0003] The applications of filler-containing films include matte film, capacitor film, optical film, label film, antistatic film, anisotropic conductive film and many other applications (Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4).

[0004] Filler-containing membranes are typically manufactured in roll form.

[0005] However, if the filler-containing film is made into a roll, the following phenomena are likely to occur: the resin that acts as the binder for the filler overflows, or the resin that overflows from the resin layers of the stacked upper and lower films in the roll becomes connected to each other. In particular, this problem becomes more pronounced on the core side of the roll due to the tight winding.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-15680;

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-138904;

[0010] Patent document 3: Japanese Patent Application Publication No. 2013-103368;

[0011] Patent document 4: Japanese Patent Application Publication No. 2014-183266. Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] To address the aforementioned problems, the present invention aims to reduce the overflow of resin that serves as the binder in a filler-containing membrane, and to more effectively realize the functions of the filler-containing membrane.

[0014] Methods for solving problems

[0015] The inventors discovered that in a filler-containing membrane, if the average particle size of the filler is made approximately equal to the thickness of the adhesive resin layer holding the filler and the second resin layer that is stacked on the adhesive resin layer as needed, so as to suppress the variation of the distance between the fillers according to the position of the filler-containing membrane along the long side, the overflow of resin can be suppressed when it is made into a roll, and the function of the filler is also effectively brought out, thus leading to the invention.

[0016] That is, the present invention provides a filler-containing membrane, which is a strip of filler-containing membrane that holds the filler in an adhesive resin layer, wherein,

[0017] The average particle size of the filler is 1–50 μm.

[0018] The thickness of the resin layer is more than 0.5 times and less than 2 times the average particle size of the filler;

[0019] The ratio of the minimum inter-filler distance Lq to Lp at the other end, which is at least 5 m away from the first end along the long side of the membrane, is 1.2 or less. In particular, as a preferred embodiment of the filled membrane, the present invention provides a filled membrane in which the filler is conductive particles and is used as an anisotropic conductive membrane. In this filled membrane, the filler is preferably arranged in a lattice pattern.

[0020] Furthermore, the present invention also provides: a film-adhesive body obtained by adhering the above-described filler-containing film to an article; a connection structure obtained by connecting a first article and a second article via the above-described filler-containing film; in particular, a connection structure obtained by anisotropically conductively connecting a first electronic component and a second electronic component via a filler-containing film serving as an anisotropic conductive film. Moreover, the present invention also provides: a method for manufacturing a connection structure by pressing a first article and a second article together via the above-described filler-containing film; and a connection structure obtained by anisotropically conductively connecting the first electronic component and the second electronic component by heat-pressing the first electronic component and the second electronic component respectively using the first article and the second article as the first electronic component and the second electronic component, respectively, via a filler-containing film (i.e., an anisotropic conductive film) with conductive particles as filler; and a method for manufacturing the connection structure with anisotropic conductive connection. In these inventions, it is preferable that the total height of the opposing terminals of the first electronic component and the second electronic component is set to less than twice the size of the conductive particles in the anisotropic conductive film.

[0021] Invention Effects

[0022] According to the filler-containing membrane of the present invention, resin overflow of the adhesive resin layer can be reduced, and the functions of the filler-containing membrane can be more effectively realized depending on the application of the filler-containing membrane. For example, when the filler-containing membrane is a matte film, a uniform matte effect can be obtained. In addition, when the filler-containing membrane is an anisotropic conductive film, it becomes a suitable film for electronic components with connection terminal height reduced to, for example, 3 μm or less. Attached Figure Description

[0023] [ Figure 1A ] Figure 1A This is a plan view illustrating the configuration of the packing material in the packed membrane 10A.

[0024] [ Figure 1B ] Figure 1B This is a cross-sectional view of membrane 10A containing filler.

[0025] [ Figure 2 ] Figure 2 This is a cross-sectional view of the 10B membrane containing the filler.

[0026] [ Figure 3 ] Figure 3 This is a cross-sectional view of the 10C membrane containing the filler.

[0027] [ Figure 4 ] Figure 4 This is a cross-sectional view of a 10D membrane containing filler.

[0028] [ Figure 5 ] Figure 5 This is a cross-sectional view of the 10E membrane containing the filler.

[0029] [ Figure 6 ] Figure 6 This is a cross-sectional view of the 10F membrane containing the filler.

[0030] [ Figure 7 ] Figure 7 This is an explanatory diagram of the test method for the overflow test. Detailed Implementation

[0031] The filler-containing membrane of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same symbols denote the same or equivalent constituent elements.

[0032] <Integral Composition of Membrane Containing Filler>

[0033] Figure 1A This is a plan view illustrating the packing configuration of a packing membrane 10A according to an embodiment of the present invention. Figure 1B This is its XX cross-sectional view.

[0034] The filler-containing membrane 10A is a long strip, formed by a filler dispersion layer 3 in which fillers 1 arranged in a hexagonal lattice are held in an adhesive resin layer 2. The average particle size of the filler 1 is 1 to 50 μm. In this filler-containing membrane 10A, the layer thickness La of the adhesive resin layer 2 is equal to the layer thickness Lt of the resin layer of the filler-containing membrane 10A. This layer thickness La is at least 0.5 times and less than 2 times, preferably at least 0.7 times and less than 1.3 times, the average particle size of the filler 1, and is approximately equal to the average particle size of the filler 1. Furthermore, as will be described later, the filler 1 is preferably evenly distributed.

[0035] <Packaging>

[0036] Filler 1 is selected appropriately from known inorganic fillers (metals, metal oxides, metal nitrides, etc.), organic fillers (resin particles, rubber particles, etc.), and fillers containing a mixture of organic and inorganic materials (e.g., particles with a core formed of resin material and a surface plated with metal (metal-coated resin particles), fillers with insulating microparticles attached to the surface of conductive particles, fillers with insulating treatment on the surface of conductive particles, etc.), based on the performance requirements of the application, such as hardness and optical properties. For example, in optical films or matte films, silica fillers, titanium dioxide fillers, styrene fillers, acrylic fillers, melamine fillers, or various titanates can be used. In capacitor films, titanium oxide, magnesium titanate, zinc titanate, bismuth titanate, lanthanum oxide, calcium titanate, strontium titanate, barium titanate, barium zirconate titanate, lead zirconate titanate, and mixtures thereof can be used. In adhesive films, polymer-based rubber particles, silicone rubber particles, etc., can be contained. In anisotropic conductive films, conductive particles are contained. Examples of 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 with insulating microparticles attached to their surface. Two or more types may be used in combination. Among these, metal-coated resin particles are preferred from the perspective of easy maintenance of contact between the resin particles and the terminals after connection, and stable conductivity. Furthermore, the surface of the conductive particles can be insulated using known techniques without impairing conductivity. The fillers listed above according to their intended use are not limited to this application; filler-containing films for other applications may also contain them as needed. Additionally, in filler-containing films for each application, two or more fillers may be used in combination as needed.

[0037] The shape of the filler is appropriately selected from spherical, ellipsoidal, columnar, needle-shaped, and combinations thereof, depending on the application of the filler-containing membrane. From the perspective of facilitating the confirmation of filler configuration and maintaining a uniform state, a spherical shape is preferred. In particular, when the filler-containing membrane is constructed as an anisotropic conductive membrane, the conductive particles used as filler are preferably approximately spherical. By using approximately spherical particles as conductive particles, for example, as described in Japanese Patent Application Publication No. 2014-60150, when manufacturing an anisotropic conductive membrane with conductive particles arranged thereon using a transfer mold, the conductive particles are smoothly transferred onto the transfer mold, thus allowing for high-precision filling of conductive particles at predetermined positions on the transfer mold. Therefore, the conductive particles can be precisely configured.

[0038] <Particle size of filler>

[0039] The particle size of the filler is appropriately determined according to the application of the filler-containing membrane. However, in this invention, since the average particle size of the filler is approximately equal to the total thickness of the resin layer in the filler-containing membrane, it is preferable to set it to 1 μm or more and 50 μm or less from the perspective of membrane operability, etc. In particular, when the filler-containing membrane is used as an anisotropic conductive membrane (when the filler is conductive particles), it is preferable to set it to 1 μm or more and 30 μm or less from the perspective of dealing with deviations in wiring height or wiring flatness, suppressing the increase of conduction resistance, and suppressing the occurrence of short circuits. In particular, when the thickness of the connection terminal is reduced to about 3 μm or less, it is preferable to set it to 2.5 μm or more and 20 μm or less. It should be noted that in this case, the terminal is preferably at least one of the terminals of an anisotropic conductive connection such as an IC chip or FPC (preferably an electronic component with the top of the terminal protruding from the substrate on which the terminal is provided). As for the material of the terminal, examples include materials known to be used in electronic components such as gold, copper, and tin.

[0040] It should be noted that the particle size of the filler can be measured using a common particle size distribution measuring device, and the average particle size can also be determined using a particle size distribution measuring device. An example of such a device is the FPIA-3000 (Malvern). In this case, it is desirable to have at least 200 samples for particle size measurement, preferably at least 1000, and more preferably at least 5000. Alternatively, it is sometimes preferable to use a metal microscope or scanning electron microscope to observe samples in which the filler is dispersed on a flat plate such as a glass plate, or samples in which a curable resin composition is mixed, dispersed, and then coated, to determine the particle size or average particle size. This is because, in the case of an aspect ratio, the size can be determined from the Z-axis (focus adjustment) of the observation device. Furthermore, if the filler is not spherical, the average particle size can be determined by using a planar or cross-sectional image of the filler-containing membrane, taking the maximum length or the diameter that mimics a spherical shape as the particle size of the filler.

[0041] <Packaging Arrangement>

[0042] In the filler-containing membrane of the present invention, the arrangement of the fillers is arbitrary as long as the conditions regarding the total thickness of the resin layer or the minimum inter-filler distance described later are met; however, from the viewpoint of obtaining the inventive effect, a grid pattern is preferred. Figure 1A In the filled membrane 10A shown, the filler 1 is arranged regularly in a grid pattern when viewed from above. By arranging it in a grid pattern, the filler particles do not contact each other and are easier to position evenly. Therefore, by tightly winding the filled membrane, areas prone to resin overflow or leakage can be prevented. Thus, even if resin overflow or leakage occurs at a certain point, it can be prevented from further expanding in the upper and lower resin layers that are overlapped by winding. It should be noted that the same effect can sometimes be obtained even if the filler arrangement is arbitrary.

[0043] Here, as a lattice-like arrangement scheme, besides Figure 1ABesides the hexagonal grid shown, other grid arrangements include rectangular grids, rhomboid grids, square grids, and other rectangular grids. Among these, forming a hexagonal, square, or rhomboid grid (i.e., a diamond grid) allows for a more even arrangement of the fillers, which is therefore preferred. It should be noted that in this invention, the grid-like arrangement also includes arrangements of conductive particle groups in a grid pattern. The conductive particles forming this group preferably exhibit regularity within the group. Furthermore, arrangements obtained by regularly extracting a portion of the filler from the grid-like conductive particles are also included. The vacancies in the filler can be identified by their regular existence in a predetermined direction of the membrane within the range that achieves the desired effect of the filler-containing membrane. Additionally, by repeatedly presenting filler vacancies along the long side of the membrane, or by gradually increasing or decreasing the number of filler vacancies along the long side of the membrane, batch management can be implemented, and the filler-containing membrane and the connecting structure using it can be given traceability capabilities (a traceable property). This is also effective for preventing counterfeiting, verifying authenticity, and preventing improper use of membranes containing fillers or connecting structures that use them.

[0044] In this invention, regardless of the position of the long side of the filler membrane, the regularity of the grid-like filler arrangement remains stable. When the minimum inter-filler distance at one end along the long side of the filler membrane is defined as Lp, and the minimum inter-filler distance at the other end, located at least 5m away from this end along the long side of the membrane, is defined as Lq, the ratio Lq / Lp is 1.2 or less. By measuring the shortest distances of the inter-grid distances of 10 or more, preferably 20 or more, and more preferably 100 or more fillers arranged in a grid pattern at one end and the other end respectively, and calculating the minimum inter-filler distance Lp and the minimum inter-filler distance Lq at the other end, the ratio Lq / Lp can be determined.

[0045] Furthermore, in this invention, as a parameter for the uniform arrangement of packing 1, it is preferable to set the ratio (Lmax / Lmin) obtained as follows to be 1 or more and 1.2 or less. That is, in regions where 10 or more, preferably 20 or more, parts are randomly extracted from the entire membrane, or regions that reach 1% or more, preferably 2% or more of the total membrane length, an arbitrary packing P0 is selected in each region, and three packings P1, P2, and P3 are selected in order of their closest distance to the packing P0. Among the distances L1, L2, and L3 between the three packings P1, P2, and P3 and the packing P0, the ratio (Lmax / Lmin) of the maximum distance (Lmax) to the minimum distance (Lmin) is taken. Figure 1AWhen the average value is 1.0 or more and 1.2 or less, preferably 1.1 or less, and more preferably 1.05 or less, the average value is preferably 1.0 or more and 1.2 or less, preferably 1.1 or less, and more preferably 1.05 or less. In particular, when the packing 1 is arranged in a hexagonal grid, when five packings P1, P2, P3, P4, and P5 are selected in order of proximity to any packing P0, and the ratio of the maximum distance (Lmax) to the minimum distance (Lmin) (Lmax / Lmin) is calculated in the same manner as above, the average value is preferably 1.0 or more and 1.1 or less. In addition, when three packings P1, P2, and P3, preferably five packings P1, P2, P3, P4, and P5 are selected in order of proximity to any packing P0, and the average value of the ratio of the maximum distance (Lmax) to the minimum distance (Lmin) (Lmax / Lmin) is calculated in the same manner as above, the packing arrangement may not be a grid arrangement if the average value is 1.0 or more and 1.2 or less, preferably 1.1 or less, and more preferably 1.05 or less. Preferably, even P1, which is adjacent to any filler P0, reaches the same numerical range; more preferably, even P2 reaches the same numerical range; and even more preferably, even P3 reaches the same numerical range. In this way, it can be said that the dispersion is approximately uniform on a surface.

[0046] When the filler is arranged in a hexagonal, square, or rhomboid grid (diamond grid), the aforementioned ratio (Lmax / Lmin) is designed to be 1. However, in practice, slight positional shifts can occur during the manufacturing of the filler-containing membrane. Furthermore, if the filler-containing membrane is made into a roll, there is a concern that slight positional shifts may also occur due to the tightness of the roll due to the thickness of the filler-containing membrane. In contrast, the upper limit of the aforementioned ratio (Lmax / Lmin) becomes the acceptable range for the positional shift of the filler in this invention. In this invention, by suppressing this acceptable range to a low level, a state in which the fillers do not contact each other and are evenly distributed is formed, thereby preventing resin overflow or seepage. In addition, when the filler is a conductive particle and the filler-containing membrane is an anisotropic conductive membrane, pressure can be applied evenly to each conductive particle 1 during anisotropic conductive connection, effectively reducing the deviation of the conduction resistance, and also preventing short circuits.

[0047] In filler-containing films, it is desirable that the ratio (Lmax / Lmin) falls within the aforementioned range, and this can be achieved at any point along the film. This can be easily confirmed by examining both ends of the filler-containing film along its long side. Specifically, when the filler-containing film is wound onto a core to form a roll, and the core diameter is set to 2R, the aforementioned ratio (Lmax / Lmin) only needs to be between 1.0 and 1.2 in a region extending 2πR from one end of the filler-containing film on the core side (i.e., the circumference of the core). This is because tension due to winding is most likely to occur in this region, thus the ratio (Lmax / Lmin) is prone to variation. It should also be noted that one end of the filler-containing film on the core side refers to, for example, the portion where the guide portion of the core is connected to the filler-containing film (or the substrate film supporting it). The other end refers to the position where the film is removed from the roll formed using the core. The length from one end to the other varies depending on the length of the filler membrane, but when studying the ratio (Lmax / Lmin) at the other end, it is preferable if the average value of the ratio (Lmax / Lmin) of more than 10 sites arbitrarily selected from the length of more than 1 circumference of the outermost periphery is 1.0 or more and 1.2 or less.

[0048] Furthermore, in the filler-containing membrane of the present invention, the proportion of fillers existing without contact with each other by arbitrarily configuring the fillers or arranging the fillers in a grid pattern as described above is 95% or more, preferably 98% or more, and more preferably 99.5% or more.

[0049] It should be noted that, as a method to suppress minute positional displacement of the filler and prevent the fillers from contacting each other, as described later, it is preferable to pre-fabricate a mold that specifies the location where the filler should be placed when manufacturing the filler-containing membrane, place the filler at that location, and then transfer the filler to the adhesive resin layer.

[0050] It should be noted that when using a filler-containing film as an anisotropic conductive film, the lattice axis of the filler arranged in a grid pattern can be parallel to or intersect the long side direction of the anisotropic conductive film, depending on the width and spacing of the terminals to be connected. For example, in the case of anisotropic conductive film used for fine-pitch applications, such as... Figure 1A As shown, at least one lattice axis A of the conductive particle 1 is inclined relative to the long side direction of the anisotropic conductive film 10A, and the angle θ between the long side direction of the terminal 20 connected through the anisotropic conductive film 10A and the lattice axis A is preferably 16° to 74°. Even in applications other than those using anisotropic conductive films, the effect of stabilizing the capture state can be expected by tilting it in this way.

[0051] <Packaging density and area occupancy>

[0052] The number density and area occupancy of the filler are appropriately determined based on the application of the filler-containing membrane and the particle size of the filler. For example, when conductive particles are used as fillers and the filler-containing membrane is used as an anisotropic conductive membrane, if the number density of conductive particles is too small, it will not be able to handle the connection of electronic components with fine pitch; if it is too large, it may cause short circuits. Therefore, when the particle size is 1–30 μm, a density of 30–72,000 particles / mm is preferred. 2 More preferably, 50 to 50,000 pieces / mm 2 For the same reasons as filler density, the area occupancy of the membrane in top view (filler density × average area of ​​one filler × 100) is preferably set to 0.1–35%, more preferably 0.5–30%. Since the manufacturing conditions for filler-containing membranes other than anisotropic conductive membranes are largely the same as those for anisotropic conductive membranes (because there are no significant differences), it can be assumed that the conditions for filler density and area occupancy are also largely the same from a design perspective. When the filler-containing membrane is manufactured into a roll, a filler area occupancy that is high enough can suppress resin overflow; therefore, the lower limit is preferably 6% or more, more preferably 12% or more (the upper limit is also preferably 35% or less, more preferably 30% or less, as described above). If it is 35% or more, there is a concern that filler contact may compromise independence. It should be noted that, as mentioned above, the filler density or area occupancy is not limited to these ranges.

[0053] <Adhesive Resin Layer>

[0054] (Viscosity of the adhesive resin layer)

[0055] There is no particular limitation on the minimum melt viscosity of the adhesive resin layer 2, and it can be appropriately determined according to the application of the filler-containing film or the manufacturing method of the filler-containing film. For example, as long as the depressions 2b and 2c described later can be formed, it can be set to about 1000 Pa·s according to the manufacturing method of the filler-containing film. On the other hand, as a manufacturing method of the filler-containing film, when the filler is held on the surface of the resin layer in a prescribed configuration and the filler is pressed into the resin layer, from the perspective of the resin layer being able to form a film, it is preferable to set the minimum melt viscosity of the resin to 1100 Pa·s or more.

[0056] Furthermore, as explained later in the method for manufacturing a filler-containing membrane, from such Figure 1B As shown, a recess 2b is formed around the exposed portion of the filler 1 pressed into the adhesive resin layer 2, or as shown in the diagram. Figure 2Considering the angle at which the recess 2c is formed directly above the filler 1 pressed into the adhesive resin layer 2, the minimum melt viscosity of the adhesive resin layer 2 is preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, further preferably 3000 to 15000 Pa·s, and even more preferably 3000 to 10000 Pa·s. As an example, this minimum melt viscosity can be determined using a rotational rheometer (manufactured by TA Instruments) at a constant measuring pressure of 5g using a measuring plate with a diameter of 8mm. More specifically, it can be determined by using a temperature range of 30 to 200°C, a heating rate of 10°C / min, a measuring frequency of 10Hz, and a load variation of 5g on the measuring plate.

[0057] By setting the minimum melt viscosity of the adhesive resin layer 2 to a high viscosity of 1500 Pa·s or more, unnecessary movement of filler generated during the pressing of the filler-containing film onto the article can be suppressed. In particular, when the filler-containing film is used as an anisotropic conductive film, it can prevent conductive particles that should be held between the terminals during anisotropic conductive connection from flowing due to resin flow.

[0058] Furthermore, when a filler dispersion layer 3 containing a filler film 10A is formed by pressing filler 1 into adhesive resin layer 2, regarding adhesive resin layer 2 when filling 1 is pressed in, when filling 1 is pressed into adhesive resin layer 2 and the filler 1 is exposed from adhesive resin layer 2, adhesive resin layer 2 undergoes plastic deformation, resulting in a depression 2b formed in adhesive resin layer 2 around filler 1. Figure 1B The high-viscosity viscous body, or, when the filler 1 is pressed in such that it is not exposed from the adhesive resin layer 2 but embedded in the adhesive resin layer 2, a depression 2c is formed on the surface of the adhesive resin layer 2 directly above the filler 1. Figure 2 The adhesive resin layer 2 is a highly viscous viscous substance. Therefore, regarding the viscosity of the adhesive resin layer 2 at 60°C, the lower limit is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. This determination can be performed using the same method as for determining the minimum melt viscosity of the adhesive resin layer, by extracting the value at a temperature of 60°C.

[0059] Regarding the specific viscosity of the adhesive resin layer 2 when the filler 1 is pressed into it, depending on the shape or depth of the recesses 2b and 2c to be formed, the lower limit is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. Furthermore, such a viscosity is obtained preferably at 40–80°C, more preferably 50–60°C.

[0060] As described above, by forming a depression 2b around the filler 1 exposed from the resin layer 2 ( Figure 1B When the filler-containing membrane is pressed onto an article, the flattening of the filler 1 reduces the resistance from the resin compared to the case without the recess 2b. Therefore, when the filler-containing membrane is used as an anisotropic conductive membrane, conductive particles are easily held by the terminals during anisotropic conductive connections, thereby improving both conductivity and trapping ability.

[0061] Additionally, a recess 2c is formed on the surface of the adhesive resin layer 2 directly above the filler 1, which is embedded without being exposed from the adhesive resin layer 2. Figure 2 Compared to the case without recess 2c, the pressure during pressing of the filler-containing membrane onto the article tends to concentrate on the filler 1. Therefore, when the filler-containing membrane is used as an anisotropic conductive membrane, the conductive particles are easily held by the terminals during anisotropic conductive connections, thereby improving capture and conductivity. Since the filler-containing membrane of the present invention has a relatively small amount of resin, the aforementioned recess 2b or recess 2c exists, which makes it easier for the filler to be held by the article (conductive particles and terminals or electrodes in the case of anisotropic conductive membranes), and the effect of suppressing the pressing force at a low level is expected. It is also expected that the independence of the captured filler after pressing will be easier to maintain before and after pressing. This is because the amount of flowing resin itself is relatively small.

[0062] <Instead of "sloping" or "undulating">

[0063] like Figure 1B , Figure 2 The "recesses" 2b and 2c of the filled film (anisotropic conductive film) shown can also be described from the viewpoint of "tilt" or "undulation". The following explanation will be given with reference to the accompanying drawings.

[0064] The 10A membrane containing filler (anisotropic conductive membrane) is composed of a filler dispersion layer 3 consisting of filler 1 such as conductive particles. Figure 1BIn the filler dispersion layer 3, the filler 1 is regularly dispersed with one side exposed above the adhesive resin layer 2. When viewed from above, the fillers 1 do not contact each other, and in the film thickness direction, the fillers 1 are also regularly dispersed without overlapping, forming a single-layer filler (e.g., conductive particle) layer in which the fillers 1 are aligned in the film thickness direction.

[0065] On the surface 2a of the adhesive resin layer 2 surrounding each filler 1, an inclination 2b is formed relative to the cross-section 2p of the adhesive resin layer 2 at the center between adjacent fillers. It should be noted that, as described later, in the anisotropic conductive film and other filler-containing films of the present invention, an undulation 2c may also be formed on the surface of the adhesive resin layer directly above the filler 1 embedded in the adhesive resin layer 2. Figure 2 ).

[0066] In this invention, "tilt" refers to a state where the surface flatness of the adhesive resin layer near filler 1 is damaged, resulting in a partial defect of the adhesive resin layer relative to the aforementioned cross-section 2p, thereby leading to a reduction in resin content. In other words, in a tilted state, the surface of the adhesive resin layer around the filler is defective relative to the cross-section. On the other hand, "undulation" refers to a state where the surface of the adhesive resin layer directly above the filler has waves, with a portion having a height difference like waves, thereby leading to a reduction in resin content. In other words, the amount of resin in the adhesive resin layer directly above the filler is less than when the surface of the adhesive resin layer directly above the filler is on the cross-section. This can be identified by comparing the portion corresponding to the area directly above the filler with the flat surface portion between the fillers. It should be noted that sometimes the starting point of the undulation also exists in the form of a tilt.

[0067] As described above, by forming an inclined 2b around the filler 1 exposed from the adhesive resin layer 2... Figure 1B When a filler-containing film is constructed as an anisotropic conductive film, the flattening of the filler 1, which acts as conductive particles, during anisotropic conductive connection and is clamped between terminals, reduces the resistance from the resin compared to the case without tilt 2b. Therefore, the filler is easily clamped in the terminals, thereby improving conductivity and trapping ability. This tilt is preferably along the shape of the filler. This is because, in addition to making the connection effect easier to observe, the filler is also easier to identify, thus facilitating inspections during the manufacturing of filler-containing films such as anisotropic conductive films. Furthermore, this tilt and undulation may sometimes disappear partially due to hot pressing or other processes on the adhesive resin layer; this invention covers such cases. In these cases, the filler may sometimes be exposed at a point on the surface of the resin layer. It should be noted that, since there are many different electronic components to be connected, in addition to adjustments based on these, a high degree of design freedom is desired to meet various requirements. Therefore, anisotropic conductive films can be used with reduced tilt or undulation, or with some of the tilt or undulation eliminated.

[0068] Additionally, undulations 2c are formed on the surface of the adhesive resin layer 2 directly above the filler 1, which is embedded without being exposed from the adhesive resin layer 2. Figure 2 Similar to the inclined case, it is easier to apply pressure from the terminal to the filler during anisotropic conductive connections. Furthermore, by having undulations, compared to the case of flat adhesive resin stacking, the amount of adhesive resin directly above the filler is reduced. Therefore, the adhesive resin directly above the filler is easily expelled during connection, making it easier for the terminal to contact the filler. This improves the filler's hold-up in the terminal and enhances conductive reliability. The same effect can be obtained in solutions other than anisotropic conductive films containing filler films.

[0069] (The position of the filler in the thickness direction of the adhesive resin layer)

[0070] Considering the perspective of "inclination" or "undulation," the position of the filler 1 in the thickness direction of the adhesive resin layer 2 can be either exposed from the adhesive resin layer 2 or embedded within it. However, the ratio of the distance Lb (hereinafter referred to as the embedment amount) from the deepest part of the filler to the cross-section 2p between the center of adjacent fillers to the average particle size D of the filler (Lb / D) (hereinafter referred to as the embedment rate) is preferably 60% or more and 105% or less. It should be noted that the filler 1 can penetrate the adhesive resin layer 2. In the case of penetration, the embedment rate is 100%.

[0071] By setting the embedment ratio (Lb / D) to 60% or more, the filler 1 is maintained in a specified particle dispersion state or a specified arrangement by the adhesive resin layer 2. Furthermore, by setting it to 105% or less, when the filler-containing film is constructed as an anisotropic conductive film, the amount of adhesive resin layer (insulating resin layer) that causes unnecessary movement of the filler (conductive particles) between terminals during anisotropic conductive connections can be reduced. The same effect can be obtained in solutions other than anisotropic conductive films containing filler films.

[0072] It should be noted that the embedment ratio (Lb / D) refers to a value where the total number of fillers (e.g., conductive particles) contained in a filler-containing film such as an anisotropic conductive film is 80% or more, preferably 90% or more, more preferably 96% or more, and even more preferably 99% or more. Therefore, an embedment ratio of 60% or more and 105% or less means that the embedment ratio of 80% or more, preferably 90% or more, more preferably 96% or more, and even more preferably 99% or more in a filler-containing film such as anisotropic conductive film is 60% or more and 105% or less. In this way, by making the embedment ratio (Lb / D) of all fillers consistent, the pressure load (weight) is applied evenly to the fillers, thus improving the capture state of the fillers in the terminals and increasing the stability of conductivity in the case of anisotropic conductive films. The same effect can be obtained in solutions other than anisotropic conductive films containing fillers.

[0073] The embedment ratio (Lb / D) can be determined by randomly sampling 10 or more locations with an area of ​​30 mm² from a filler film such as anisotropic conductive film. 2 The above area is determined by observing a portion of the membrane cross-section in an SEM image and measuring a total of more than 50 conductive particles. To further improve accuracy, the determination can also be made by measuring more than 200 filler particles.

[0074] Alternatively, the embedment ratio (Lb / D) can be measured by adjusting the focus in a planar field-of-view image and calculating the number of elements at a certain level. Alternatively, the embedment ratio (Lb / D) can also be measured using a laser-type discrimination displacement sensor (e.g., Keyence Co., Ltd.).

[0075] For a more specific embedment scheme of filler 1 with an embedment ratio (Lb / D) of 60% or more and 105% or less, the following can be listed first: Figure 1B As shown in the filler-containing membrane 10A, the filler 1 is embedded in a manner that exposes from the adhesive resin layer 2 with an embedment rate of 60% or more but less than 100%. In this filler-containing membrane 10A, the portion of the surface of the adhesive resin layer 2 that contacts the filler 1 exposed from the resin layer 2 and its vicinity has an inclination 2b relative to the cross-section 2p of the surface 2a of the insulating resin layer at the center between adjacent fillers. This inclination forms an ridge line that generally follows the shape of the filler.

[0076] Such tilt 2b or undulation 2c, as described later, is obtained when a filler-containing film 10A, such as an anisotropic conductive film, is manufactured by pressing filler 1 into the adhesive resin layer 2. The lower limit of the viscosity at which filler 1 is pressed is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and even more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and even more preferably 10000 Pa·s or less. Furthermore, such viscosity is preferably obtained at 40–80°C, more preferably 50–60°C. It should be noted that by hot pressing or the like, a portion of the tilt 2b or undulation 2c may disappear, and the tilt 2b may also become undulation 2c. Additionally, the filler with undulation 2c may be exposed at a point on its top of the adhesive resin layer 2.

[0077] The inclined 2b of the adhesive resin layer 2 around the exposed portion of the filler described above is easily obtained. Figure 1B ), or the undulations of the adhesive resin layer directly above the filler 2c ( Figure 2 From the perspective of the effect, the ratio of the maximum depth Lh of the inclined 2b to the average particle size D of the filler 1 (Lh / D) is preferably less than 50%, more preferably less than 30%, and even more preferably 20-25%. The ratio of the maximum diameter Lg of the inclined 2b or the undulation 2c to the average particle size D of the filler 1 (Lg / D) is preferably more than 100%, more preferably 100-150%. The ratio of the maximum depth Lf of the undulation 2c to the average particle size D of the filler 1 (Lf / D) is greater than 0, preferably less than 10%, and more preferably less than 5%.

[0078] It should be noted that the diameter Lc of the exposed (directly above) portion of the filler 1 in the inclined 2b or undulating 2c can be set to be less than or equal to the average particle size D of the filler 1, preferably 10 to 90% of the average particle size D. It can be set to be exposed at a point on the top of the filler 1, or it can be set to be completely embedded in the adhesive resin layer 2, with a diameter Lc of 0.

[0079] In this invention, the presence of tilt 2b and undulation 2c on the surface of the adhesive resin layer 2 can be confirmed by observing the cross-section of a filler-containing film such as an anisotropic conductive film using a scanning electron microscope, or by observing in a planar field of view. Tilting 2b and undulation 2c can also be observed using an optical microscope or a metal microscope. Furthermore, the size of tilt 2b and undulation 2c can be confirmed by adjusting the focus during image observation. As mentioned above, this remains even after the tilt or undulation is reduced by hot pressing. This is because traces may sometimes remain.

[0080] (Composition of the adhesive resin layer)

[0081] The adhesive resin layer 2 can be conductive or insulating, depending on the application of the filler-containing membrane. It can also be plasticizing or curable, but preferably it can be formed from an insulating curable resin composition, for example, a thermally polymerizable composition containing a thermally polymerizable compound and a thermally polymerizable initiator. The thermally polymerizable composition may contain a photopolymerization initiator if needed. These can use known resin compositions and curing agents and initiators. Hereinafter, the case of an insulating resin will be described, primarily using an anisotropic conductive film as an example of a filler-containing membrane.

[0082] When using both thermal polymerization initiators and photopolymerization initiators, compounds that function as both thermal and photopolymerizable compounds can be used, or compounds that contain photopolymerizable compounds in addition to thermal polymerization compounds can be used. It is preferable to contain photopolymerizable compounds in addition to thermal polymerization compounds. For example, thermal cationic polymerization initiators can be used as thermal polymerization initiators, epoxy compounds can be used as thermal polymerization compounds, photoradical polymerization initiators can be used as photopolymerization initiators, and acrylate compounds can be used as photopolymerizable compounds.

[0083] As a photopolymerization initiator, it can contain multiple light-reacting molecules with different wavelengths. Therefore, in the manufacture of filler-containing films, the wavelengths used in the photocuring of the resin constituting the adhesive resin layer and the photocuring used when the filler-containing film is bonded to the adherend (e.g., photocuring of the resin used to bond electronic components to each other in anisotropic conductive bonding) can be used separately.

[0084] In the photocuring process during the manufacture of the filler-containing membrane, all or part of the photopolymerizable compound contained in the adhesive resin layer can be photocured. Through this photocuring, the configuration of filler 1 in the adhesive resin layer 2 is maintained or even fixed. Furthermore, through this photocuring, the viscosity of the adhesive resin layer in the manufacturing process of the filler-containing membrane can be appropriately adjusted. In particular, this photocuring is preferably performed when the ratio (La / D) of the thickness La of the adhesive resin layer 2 to the average particle size D of the filler 1 is less than 0.6. This is because when the thickness of the adhesive resin layer 2 is thin relative to the average particle size D of the filler 1, adjusting the viscosity of the adhesive resin layer 2 while more reliably maintaining or fixing the configuration of the filler 1 in the adhesive resin layer 2 also suppresses a decrease in yield when bonding the filler-containing membrane to the substrate.

[0085] The amount of photopolymerizable compound in the adhesive resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably less than 2% by mass. This is because if there is too much photopolymerizable compound, the pushing force required for pressing in the case of hot pressing a filler-containing film onto the adherend increases. This is especially preferable in the case of anisotropic conductive bonding. This is to balance resin flow and the pressing in of conductive particles retained in the resin.

[0086] Examples of thermopolymerizable compositions include: thermopolymerizable acrylate compositions containing (meth)acrylate compounds and thermopolymerizable free radical initiators, and thermopolymerizable cationic epoxy compositions containing epoxy compounds and thermopolymerizable cationic initiators. Thermopolymerizable anionic epoxy compositions containing thermopolymerizable anionic initiators can also be used instead of thermopolymerizable cationic epoxy compositions containing thermopolymerizable cationic initiators. Furthermore, multiple polymerizable compositions can be used in combination, provided that no particular obstacles are encountered. Examples of parallel applications include the combined use of cationic polymerizable compositions and thermopolymerizable free radical polymerizable compositions.

[0087] Here, conventionally known thermopolymerizable (meth)acrylate monomers can be used as (meth)acrylate compounds. For example, monofunctional (meth)acrylate monomers or difunctional or more polyfunctional (meth)acrylate monomers can be used.

[0088] Examples of initiators for thermal free radical polymerization include organic peroxides and azo compounds. In particular, organic peroxides that do not generate nitrogen that leads to bubble formation are preferred.

[0089] Regarding the amount of thermal free radical polymerization initiator used, if too little is used, the curing will be poor, and if too much is used, the product life will be reduced. Therefore, relative to 100 parts by weight of (meth)acrylate compound, it is preferred to be 2 to 60 parts by weight, and more preferably 5 to 40 parts by weight.

[0090] Examples of epoxy compounds include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic varnish type epoxy resin, their modified epoxy resins, alicyclic epoxy resins, etc., and two or more of them can be used in combination. In addition to epoxy compounds, oxetane compounds can also be used in combination.

[0091] As a thermal cationic polymerization initiator, compounds known as thermal cationic polymerization initiators for epoxy compounds can be used, such as iodonium salts, sulfonium salts, phosphonium salts, ferrocene salts, etc., which generate acids by heat. In particular, aromatic sulfonium salts that exhibit good latency to temperature are preferred.

[0092] Regarding the amount of thermal cationic polymerization initiator used, too little will tend to result in poor curing, while too much will tend to reduce product life. Therefore, relative to 100 parts by weight of epoxy compound, it is preferred to be 2 to 60 parts by weight, and more preferably 5 to 40 parts by weight.

[0093] The thermopolymerizable 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, polyurethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefin resins; two or more of these can be used in combination. Among these, phenoxy resins are preferred from the viewpoints of film-forming properties, processability, and bonding reliability. The weight-average molecular weight is preferably 10,000 or higher. Examples of silane coupling agents include epoxy-based silane coupling agents and acrylic-based silane coupling agents. These silane coupling agents are primarily alkoxysilane derivatives.

[0094] In the thermopolymerizable composition, in order to adjust the melt viscosity, an insulating filler may be included in addition to filler 1 described above. Examples of such fillers include silica powder and alumina powder. The insulating filler is preferably a microfiller with a particle size of 20 to 1000 nm. Furthermore, the amount of the filler is preferably 5 to 50 parts by mass relative to 100 parts by mass of the thermopolymerizable compound (photopolymerizable composition) such as the epoxy compound. The insulating filler included in addition to filler 1 is preferably used when the purpose of the filler-containing film is an anisotropic conductive film, but it may not be insulating depending on the purpose; for example, conductive microfillers may be included. When the filler-containing film is constructed as an anisotropic conductive film, an even smaller insulating filler (so-called nanofiller) different from filler 1 may be appropriately included in the resin layer forming the filler dispersion layer, as needed.

[0095] In addition to the insulating or conductive fillers mentioned above, the filler membrane of the present invention may also contain fillers, softeners, accelerators, anti-aging agents, colorants (pigments, dyes), organic solvents, ion scavengers, etc.

[0096] <Thickness of the adhesive resin layer>

[0097] The thickness La of the adhesive resin layer 2 is preferably determined based on the average particle size D of the filler 1, such as... Figure 1A and Figure 1B As shown, when the resin layer in the filler-containing membrane is composed of a single layer of adhesive resin, the ratio (La / D) is small. If the amount of resin is too small, it is difficult to maintain the filler 1 in a specified dispersion or lattice configuration. Therefore, in this invention, it is set to 0.5 or more, preferably 0.6 or more, and more preferably 0.7 or more. On the other hand, if this ratio (La / D) becomes large and the amount of resin is excessive, overflow is likely to occur. Therefore, in this invention, it is set to 2 or less, preferably 1.6 or less, and more preferably less than 1.3.

[0098] It should be noted that the positional relationship between the adhesive resin layer 2 and the filler 1 in the film thickness direction can be described as follows: Figure 1B The filler 1 shown is exposed on one side of the adhesive resin layer 2, or it can be as follows: Figure 2 As shown in the filler membrane 10B, the filler 1 is not exposed from both sides of the adhesive resin layer 2, but rather embedded within the adhesive resin layer 2. It can also be like... Figure 3 As shown in the filler-containing membrane 10C, the filler 1 is exposed on both sides of the adhesive resin layer 2. In these cases, of the two membrane surfaces of the adhesive resin layer 2, the membrane surface closer to the filler 1 is preferably aligned with the filler 1 on one surface.

[0099] <Second Resin Layer>

[0100] The filler-containing membrane of the present invention can be used as needed, such as Figure 4 The 10D membrane with filler shown is as follows. Figure 5 As shown in the filler-containing membrane 10E, a second resin layer 4 is preferably laminated on the adhesive resin layer 2 with a minimum melt viscosity lower than that of the adhesive resin layer.

[0101] In this case, the total thickness Lt of the resin layer, which is the sum of the thickness La of the adhesive resin layer 2 and the thickness Ld of the second resin layer 4, is preferably 0.5 times to 2 times the average particle size D of the filler 1. It should be noted that the lower limit of 0.5 times also includes cases where the second resin layer is infinitely thin. When Lt falls within this range, a third resin layer, preferably with a minimum melt viscosity lower than or equal to that of the adhesive resin layer, can be provided, similar to the second resin layer. The third resin layer can be provided on the side of the adhesive resin layer opposite to the second resin layer, or it can be laminated on one side of the second resin layer. By laminating layers with minimum melt viscosities different from the adhesive resin layer or the second resin layer, the characteristics of the filler-containing film can be appropriately adjusted. In the case of an anisotropic conductive film as one embodiment of the filler-containing film, by appropriately filling the gaps between the terminals with resin, the adhesive strength is expected to improve. The same effect can be expected in the surface condition of the connected articles in applications other than anisotropic conductive films.

[0102] On the other hand, as a resin layer containing a filler membrane, different adhesive resin layers with different filler configurations can be stacked. The minimum melt viscosity of the adhesive resin layers with different filler configurations can be the same or different. In addition, a resin layer without filler can be placed in between, as described above as a second resin layer, or a second or third resin layer can be provided as the outermost layer. This can be done to adjust the thickness of the filler membrane itself, to ensure that the filler only contacts one side of the article, or to adjust the position of the filler between articles (without contacting any articles, etc.).

[0103] Alternatively, it can be like Figure 6 The filler-containing film 10F shown has a substrate film 5. The substrate film 5 can function as a functional film or as a release film. The substrate film 5 is not required to be a release film, therefore the present invention also includes a solution in which the substrate film 5 (functional film) and the filler-containing film 10 are integrated. Similarly, it also includes a solution in which the substrate film 5 and the filler-containing film 10 are not integrated (the filler-containing film does not include the substrate film). Examples of functional films include films that perform optical functions and films with conductive patterns on their surfaces (e.g., films with applied electrode patterns for touch sensors). Functional films can also be described as films whose effects are manifested through the physical properties of their constituent elements. By combining a functional film as a substrate film and a filler-containing film, applications such as appropriately adjusting and improving functions or endowing composite functions can be made. For example, examples include combining a filler-containing film with optical characteristics on a film with applied electrode patterns for touch sensors.

[0104] The substrate film 5 can be formed from known thermoplastic resin films such as PET (polyethylene terephthalate) film, but is not limited to these. Besides PET, examples include OPP (oriented polypropylene), PMP (poly-4-methylpentene-1), and PTFE (polytetrafluoroethylene). Furthermore, if it has a tensile modulus of elasticity equivalent to these films, it can function as a support layer for the adhesive resin layer.

[0105] From an operational perspective, the thickness Le of the substrate film 5 is preferably 20 μm or more and 100 μm or less, more preferably 25 μm or more and 85 μm or less, and even more preferably 30 μm or more and 80 μm or less. Furthermore, if the thickness Le of the substrate film 5 is sufficiently large relative to the total thickness Lt of the resin layer, resin overflow can be reduced, eliminating the problem of resin layer overflow. Therefore, as an example, it is preferable to set the thickness Le of the substrate film 5 to 10 times or less, more preferably 4 times or less, the total thickness Lt of the resin layer (in the absence of a second resin layer). On the other hand, excessively thickening the substrate film 5 is wasteful of material and makes it difficult to adequately ensure the full length of the filler-containing film in a single roll. Therefore, the thickness Le of the substrate film 5 is preferably 2 times or more, the total thickness Lt of the resin layer (in the absence of a second resin layer, the thickness La of the adhesive resin layer 2).

[0106] That is, in this invention, when the filler film 10F is an anisotropic conductive film, if the total thickness Lt of the resin layers (adhesive resin layer 2 and second resin layer 4) relative to the substrate film 5 is relatively thinner, resin overflow itself is suppressed, and the effect of reducing resin overflow can be expected. Furthermore, if the substrate film 5 is thinned, the thickness of the filler film is also thinned. Therefore, when manufacturing a roll, even if the diameter of the roll is the same as that of a known anisotropic conductive film, the film length can be longer than that of a known anisotropic conductive film. This is not limited to anisotropic conductive films.

[0107] <Total thickness of resin layer>

[0108] In the filler-containing membrane of the present invention, the lower limit of the total thickness Lt of the resin layer is preferably 0.5 times or more, 0.6 times or more, or 0.7 times or more of the average particle size D of the filler 1, and the upper limit is preferably less than 2 times, less than 1.6 times, or less than 1.3 times. When the total thickness Lt of the resin layer is less than 1 times the average particle size D of the filler 1, the filler 1 may sometimes penetrate the resin layer. Here, the total thickness Lt of the resin layer refers to, for example, Figure 1B , Figure 2 and Figure 3 As shown, in the case where the filler membranes 10A, 10B, and 10C only have the adhesive resin layer 2 as the resin layer, this refers to the thickness of the adhesive resin layer 2. Additionally, as... Figure 4 or Figure 5 As shown, when the second resin layer 4 is laminated as needed, the total thickness Lt of the resin layer refers to the combined thickness of the adhesive resin layer 2 and the second resin layer 4. On the other hand, as... Figure 6 As shown, when the substrate film 5 is used as a release film, the total thickness Lt of the resin layer does not include the thickness of the substrate film 5. The same applies when the substrate film 5 is used as a functional film.

[0109] If filler 1 is spherical, then, given the relationship between the total thickness Lt of the resin layer containing the filler membrane and the average particle size D of filler 1 as specified above, the filler content in the filler membrane is preferably 1.2 vol% or more and 45 vol% or less. On the other hand, the area occupancy of the filler in a planar view of the filler membrane is preferably 0.1% or more and 35% or less.

[0110] <Method for manufacturing membranes containing fillers>

[0111] In the case where the filler-containing membrane of the present invention is formed by a single layer of filler dispersion layer 3, the filler-containing membrane of the present invention can be manufactured, for example, by holding filler 1 on the surface of adhesive resin layer 2 in a prescribed arrangement and then pressing filler 1 into adhesive resin layer 2 with a plate or roller.

[0112] Here, the amount of filler 1 embedded in the adhesive resin layer 2 can be adjusted by the pressing pressure, temperature, etc. when pressing the filler 1. In addition, the presence, shape, and depth of the depressions 2b and 2c can be adjusted by the viscosity, pressing speed, temperature, etc. of the adhesive resin layer 2 during pressing.

[0113] Furthermore, there are no particular limitations on the method for holding the filler 1 to the adhesive resin layer 2; for example, a transfer mold can be used to hold the filler 1 to the adhesive resin layer 2. As a transfer mold, for example, a transfer mold in which an opening is formed on an inorganic material such as silicon, various ceramics, glass, or stainless steel, or an organic material such as various resins, using a known opening-forming method such as photolithography can be used. It should be noted that the transfer mold can be formed into a plate shape, a roller shape, or other shapes.

[0114] From an economic perspective when using the filler-containing membrane, it is preferable that the filler-containing membrane is of a certain length. Therefore, the length of the filler-containing membrane is preferably 5m or more, more preferably 10m or more, and even more preferably 25m or more. On the other hand, if the filler-containing membrane is too long, existing devices cannot be used as the means of bonding the filler-containing membrane to the adhered object, and the operability is also poor. Therefore, the length of the filler-containing membrane is preferably 5000m or less, more preferably 1000m or less, and even more preferably 500m or less. From the perspective of excellent operability, this long strip of filler-containing membrane is preferably made into a roll wound on a core. In addition, there is no particular limitation on the membrane width, but from the perspective of operability (workability) of winding or pulling out, the lower limit is preferably set to 0.3mm or more, more preferably 0.5mm or more, and even more preferably 0.6mm or more. In addition, the upper limit can be set to 600mm or less, but if the absolute value of the resin amount is increased excessively, there is a concern that the overflow will increase when forming long strips. Therefore, it is preferable to be 70mm or less, more preferably 50mm or less, and even more preferably 30mm or less.

[0115] <Instructions for use of membranes containing fillers>

[0116] The filler-containing film of the present invention can be used in the same way as existing filler-containing films, as long as the filler-containing film can be adhered to it, and there is no particular limitation on the article. Depending on the intended use, the filler-containing film can be adhered to various articles by pressing, preferably by heat pressing. This adhesion can be performed using light irradiation, or a combination of heat and light. For example, if the resin layer of the filler-containing film has sufficient adhesion to the article to which it is to be adhered, a film-adhesive body formed by gently pressing the resin layer of the filler-containing film onto the article surface can be obtained. In this case, the surface of the article is not limited to a flat surface; it can be uneven or curved as a whole. When the article is in film or flat shape, a pressing roller can be used to adhere the filler-containing film to these articles. Thus, the filler of the filler-containing film can also be directly bonded to the article. When the filler-containing film and the substrate film (functional film) are integrated, functionality can be imparted simply by such adhesion. For example, a filler film containing conductive particles is disposed on the surface of a substrate film (functional film) with electrode patterns, and functional films with different electrode patterns are bonded thereon, thereby forming a conductive circuit.

[0117] Alternatively, the filler-containing membrane can be placed between two opposing articles, and the two articles can be joined together using hot-pressing rollers or tools, thus holding the filler between the articles. Alternatively, the filler can be inserted into the articles without direct contact with them.

[0118] In particular, when using a filler-containing film as an anisotropic conductive film, it is preferably used when anisotropically conductively connecting first electronic components such as IC chips, IC modules, and FPCs to second electronic components such as FPCs, glass substrates, plastic substrates, rigid substrates, and ceramic substrates via a thermoforming tool. Anisotropic conductive films can also be used to stack IC chips or wafers for multilayering. It should be noted that the electronic components connected using the anisotropic conductive film of this invention are not limited to the aforementioned electronic components. In recent years, it has been used in a wide variety of electronic components.

[0119] Therefore, the present invention includes: a connection structure obtained by bonding various articles (e.g., a first article and a second article) together by pressing using the filler-containing film of the present invention, and a method thereof. In particular, when the filler-containing film is used as an anisotropic conductive film, the invention further includes a method for manufacturing a connection structure for anisotropically conductively connecting electronic components (a first electronic component and a second electronic component) together using the anisotropic conductive film; or a connection structure obtained therefrom, i.e., a connection structure obtained by anisotropically conductively connecting electronic components together using the anisotropic conductive film of the present invention.

[0120] As a method for connecting electronic components using anisotropic conductive films, when the anisotropic conductive film is composed of a single layer of conductive particle dispersion layer 3, for various substrates and other second electronic components, the anisotropic conductive film is temporarily adhered to the side where the conductive particles 1 are embedded in the surface and temporarily pressed together. An IC chip and other first electronic components are then assembled on the side of the temporarily pressed anisotropic conductive film where the conductive particles 1 are not embedded in the surface and heat-pressed together. This process can be performed. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerization compound, but also a photopolymerization initiator and a photopolymerization compound (which can be the same as the thermal polymerization compound), a heat-pressing method using both light and heat can be used. By operating in this way, unnecessary movement of the conductive particles can be minimized. Alternatively, the side where the conductive particles are not embedded can be temporarily adhered to the second electronic component for use. It should also be noted that the anisotropic conductive film can be temporarily adhered to the first electronic component instead of the second electronic component.

[0121] Furthermore, when the anisotropic conductive film is formed by a laminate of a conductive particle dispersion layer 3 and a second resin layer 4, the conductive particle dispersion layer 3 is temporarily adhered to various substrates or other second electronic components and temporarily pressed together. The second resin layer 4 side of the temporarily pressed anisotropic conductive film is then aligned with a first electronic component such as an IC chip and placed thereon, followed by heat pressing. Alternatively, the second resin layer 4 side of the anisotropic conductive film can be temporarily adhered to the first electronic component. Alternatively, the conductive particle dispersion layer 3 side can be temporarily adhered to the first electronic component for use.

[0122] Example

[0123] Hereinafter, through examples, an anisotropic conductive film, which is one embodiment of the filler-containing film of the present invention, will be specifically described.

[0124] Examples 1-4, Comparative Examples 1-4

[0125] (1) Fabrication of anisotropic conductive films

[0126] A resin composition for forming an insulating resin layer to form a conductive particle dispersion layer was prepared according to the blending methods shown in Table 1. The minimum melt viscosity of the insulating resin layer was 3000 Pa·s or higher. The resin composition was coated on a PET film with a film thickness of 50 μm using a doctor blade coater and dried in an oven at 80°C for 5 minutes to form an insulating resin layer with the film thickness shown in Table 2 on the PET film.

[0127] [Table 1]

[0128]

[0129] On the other hand, a mold was made so that conductive particles with the average particle size shown in Table 2 form a hexagonal or square lattice arrangement when viewed from above (the angle between the arrangement axis and the long side of the film is 30°), and achieve the number density shown in Table 2. Particles of a known transparent resin were injected into the mold in a molten state and cooled to solidify, thereby forming a resin mold with a hexagonal or square lattice arrangement pattern in the recesses.

[0130] Conductive particles were filled into the recesses of the resin mold, and the aforementioned insulating resin layer was coated on top. The mixture was then pressed at 60°C and 0.5 MPa to adhere the particles. The insulating resin layer was then peeled off the mold, and the conductive particles on the insulating resin layer were pressed into the insulating resin layer under pressure (pressing conditions: 60–70°C, 0.5 MPa) to form a conductive particle dispersion layer (Examples 1–4). It should be noted that, as the conductive particles with the average particle size shown in Table 2, conductive particles with an average particle size of 3 μm (AUL703, Sekisui Chemicals Co., Ltd.) were used in Examples 1 and 2, while conductive particles with an average particle size of 20 μm (Au / Ni plating, Nippon Chemical Industries Co., Ltd.) were used in Examples 3 and 4.

[0131] In Comparative Examples 1-4, conductive particles were mixed into the resin compositions shown in Table 1 for forming the insulating resin layer, resulting in an insulating resin layer in which the conductive particles were randomly dispersed in a monolayer (number density of 60,000 particles / mm). 2 ).

[0132] (2) Evaluation

[0133] For the anisotropic conductive films of the examples and comparative examples prepared in (1), the following operations were performed to evaluate (a) the consistency of interparticle distance, (b) the overflow test, (c) the connection test facing the COG, and (d) the connection test facing the FOG. The results are shown in Table 2.

[0134] (a) Consistency of inter-particle distances

[0135] Using images taken in a planar field of view using a metal microscope, the shortest distances between the grids of fillers arranged in a lattice pattern were measured at 100 locations at both ends of the anisotropic conductive film. The minimum inter-filler distance Lp at one end and Lq at the other end were calculated, and the ratio Lq / Lp was determined. Furthermore, to calculate the aforementioned ratio (Lmax / Lmin), 20 randomly selected locations, each with a 200μm × 200μm observation area, were taken off-target along the long side of the film. This was used as the total observation area, and the average ratio (Lmax / Lmin) of each observation area was calculated. Then, cases where the ratio Lq / Lp was 1.2 or less and the ratio (Lmax / Lmin) was 1 or more but less than 1.2 were considered OK, while cases that did not meet these ratio requirements were considered NG.

[0136] (b) Overflow test

[0137] A tension of 10g was applied to bring the anisotropic conductive film to the inner circumference of the PET film. The anisotropic conductive film, with widths and lengths shown in Table 2, was then wound onto a core (85mm in diameter) to create a roll. For example... Figure 7 As shown, the angle α between the straight line connecting the core 12 and the anisotropic conductive film 10 (seam 13) and the center 120 of the core, and the straight line connecting the pull-out position 14 of the film in the roll body 11 and the center 120 of the core, is set to 90° to prevent the core 12 from rotating. A load of 200g is applied to the pull-out position 14 of the film, and the roll body is left to stand at 40°C for 6 hours. Afterward, the appearance of the side of the roll body 11 is observed using a digital microscope (50-200x), and the resin overflow is evaluated according to the following criteria. Three locations are observed, including the connection between the core lead and the substrate film.

[0138] Evaluation criteria for resin overflow

[0139] The case where the PET film is sandwiched in the insulating resin layer of the anisotropic conductive film and connected to the insulating resin layer of the upper part of layer 1 is defined as "1.0 layer overflow", and the case where it is connected to the adhesive film of the upper part of layer 2 is defined as "2.0 layer overflow". The number of overflow layers is calculated to one decimal place based on the sandwiching condition of the PET film in the insulating resin layer, and the evaluation is carried out according to the following criteria.

[0140] OK: All observation sites are below layer 3.0.

[0141] NG: Even if there is an overflow of more than 3.0 layers in one part.

[0142] (c) Connectivity test for COG (c1) Initial continuity test

[0143] The anisotropic conductive films of Examples 1 and 2 and Comparative Examples 1 and 2 were cut to a sufficient area for connection and used. The evaluation IC and glass substrate shown below were heated and pressurized through the anisotropic conductive film at 180°C, 60 MPa, and 5 seconds to obtain the evaluation connector. At this time, the thrust required by the pressing clamp was 125 N.

[0144] Evaluation IC:

[0145] Dimensions: Long side 20mm, short side 90% of film width

[0146] Thickness: 0.5mm

[0147] Bump specifications: Size 30×85μm, bump spacing 10μm, bump height 3μm, number of bumps 820

[0148] Glass substrate:

[0149] Glass material: Corning 1737F

[0150] Dimensions: 30×50mm

[0151] Thickness: 0.5mm

[0152] Electrodes: ITO wiring (wiring pattern corresponds to IC bump specifications)

[0153] The initial on-resistance of the evaluation connector was measured using the four-terminal method and evaluated according to the following criteria.

[0154] OK: Less than 2Ω NG: More than 2Ω

[0155] (c2) Reliability testing

[0156] The evaluation connector obtained in (c1) was placed in a constant temperature bath at 85°C and 85%RH for 500 hours, and its on-resistance after placement was measured in the same manner as the initial on-resistance. The evaluation was carried out according to the following criteria.

[0157] OK: Less than 5Ω NG: More than 5Ω

[0158] (c3) Short circuit rate

[0159] Using the short-circuit rate evaluation IC below, the same evaluation connector as described above was obtained. The number of short circuits in the obtained evaluation connector was measured, and the short-circuit rate was calculated as the ratio of the measured number of short circuits to the number of terminals of the evaluation IC. The evaluation was carried out according to the following criteria.

[0160] Short-circuit rate is evaluated using ICs (7.5μm spacing comb-tooth TEGs (test element group)).

[0161] Dimensions: 15×13mm

[0162] Thickness: 0.5mm

[0163] Bump specifications: 25×140μm in size, 7.5μm between bumps, and 3μm in bump height.

[0164] Short circuit rate evaluation criteria:

[0165] OK: Less than 50ppm NG: More than 50ppm

[0166] (d) Connection test for FOG (d1) Initial conduction test

[0167] The anisotropic conductive films of Examples 3 and 4 and Comparative Examples 3 and 4 were cut to an area sufficient for connection and used. The evaluation FPC shown below and the glass substrate were heated and pressurized through the anisotropic conductive film at a tool width of 1.5 mm, 200°C, 5 MPa, and 5 seconds to obtain the evaluation connector. The initial on-resistance of the obtained evaluation connector was measured and evaluated according to the following criteria.

[0168] Evaluation using FPC:

[0169] Terminal pitch: 100μm

[0170] Terminal width: terminal spacing = 1:1

[0171] Polyimide film thickness / copper foil thickness (PI / Cu) = 38 / 20, Sn plating

[0172] Glass substrate:

[0173] Electrode: ITO coated

[0174] Thickness: 0.7mm

[0175] The on-resistance of the evaluation connectors was measured using the four-terminal method and evaluated according to the following criteria.

[0176] OK: Less than 2Ω NG: More than 2Ω

[0177] (d2) Conductivity reliability test

[0178] The evaluation connector obtained in (d1) was placed in a constant temperature bath at 85°C and 85%RH for 500 hours. Its on-resistance after placement was measured in the same way as the initial conduction test in (d1), and it was evaluated according to the following criteria.

[0179] OK: Less than 5Ω NG: More than 5Ω

[0180] (d3) Short circuit rate

[0181] The same FPC used for the initial continuity test (d1) was heated and pressurized on an alkali-free glass substrate (0.7 mm thick) (200 °C, 5 MPa, 5 seconds). The number of short circuits in the evaluation connectors was measured. The short circuit rate was calculated from the measured number of short circuits and the number of gaps in the evaluation connectors. The evaluation was carried out according to the following criteria.

[0182] Short circuit rate evaluation criteria:

[0183] OK: Less than 200ppm NG: More than 200ppm (d4) Bond strength

[0184] The evaluation of the bonding evaluation material obtained in (d1) was performed by cutting an FPC to make the measurement area 1 cm wide. Then, a 90-degree peel test was performed at a peeling speed of 50 mm / min to measure the force required for peeling. The evaluation was carried out according to the following standards.

[0185] OK: Bond strength is above 10 N / cm

[0186] NG: Bond strength less than 10 N / cm

[0187] [Table 2]

[0188]

[0189] Table 2 shows that in the anisotropic conductive films of Examples 1 and 2 (with a film thickness of 1.3 times the particle size and conductive particles arranged in a hexagonal lattice) or Examples 3 and 4 (with anisotropic conductive films arranged in a square lattice), no resin overflow occurred during roll forming, and good results were obtained in both COG-oriented and FOG-oriented connection tests. In contrast, in Comparative Example 1 (with a film thickness of 6 times the particle size and randomly dispersed conductive particles) and Comparative Examples 2, 3, and 4 (with a film thickness of 1.3 times the particle size but randomly dispersed conductive particles), resin overflow occurred during roll forming, resulting in poor short-circuit rates. Furthermore, in the COG-oriented connection test, Comparative Example 1 shows that a large film thickness-to-particle size ratio leads to poor initial conduction resistance or conduction reliability. It should be noted that in Comparative Examples 1-4, the overflow test conditions were set to the same level of load (50g), 23°C, and 3 hours of standing as in ordinary practical applications, and the overflow evaluation was OK. It should be noted that the total height of the terminals of the resulting connectors is the same as the bump height of the IC chip used for evaluation, or the height (copper foil thickness) of the Cu wiring of the FPC used for evaluation.

[0190] In addition, regarding the bonding strength of the connection test for FOG, OK evaluation was obtained in Examples 3 and 4, but the bonding evaluation material obtained in the initial conductivity test (c1) of Examples 1 and 2 also has bonding strength that will not cause obstacles to practical use.

[0191] In Examples 1-4, the uniformity of the inter-particle distance was excellent, but in Comparative Examples 1-4, the uniformity of the inter-particle distance was poor. Therefore, it is considered that the evaluation results of the overflow test in Comparative Examples 1-4 were poor.

[0192] Examples 5 and 6

[0193] Regarding Examples 3 and 4, except that the average particle size was set to 10 μm (Au / Ni plating, Nippon Chemical Industries, Ltd.), the thickness of the adhesive resin layer was set to 20 μm, and the distance between conductive particles was adjusted to achieve a particle number density of 1100 particles / mm, the average particle size was set to 10 μm. 2 In addition, the same operations as in Examples 1 and 2 were performed, and the evaluation was conducted. The results were substantially the same as in Examples 3 and 4 in all evaluation categories.

[0194] Comparative Examples 5 and 6

[0195] An anisotropic conductive film with an adhesive resin layer thickness of 18 μm (Comparative Example 5), the same as Comparative Example 1, was fabricated in Example 1, and an anisotropic conductive film with an adhesive resin layer thickness of 50 μm (Comparative Example 6), was fabricated in Example 3, and overflow tests were conducted on them. The results showed that the resin overflow evaluation was excellent in both Examples 1 and 3.

[0196] Symbol Explanation

[0197] 1: Filler or conductive particles;

[0198] 2: Adhesive resin layer or insulating resin layer;

[0199] 3: Filler dispersion layer or conductive particle dispersion layer;

[0200] 4: Second resin layer;

[0201] 5: Substrate film;

[0202] 10, 10A, 10B, 10C, 10D, 10E, 10F: Contains filler films or anisotropic conductive films;

[0203] 11: Rolled body;

[0204] 12: Roll core;

[0205] 120: The center of the core;

[0206] 13: The seam between the core and the anisotropic conductive film;

[0207] 14: The position where the membrane is pulled out;

[0208] 20: terminal;

[0209] A: Lattice axis;

[0210] D: Average particle size of the filler;

[0211] La: Thickness of the adhesive resin layer;

[0212] Lb: The distance to the deepest part of the packing;

[0213] Lc: Diameter of the exposed (directly above) portion of the filler;

[0214] Ld: Thickness of the second resin layer;

[0215] Le: Thickness of the substrate film;

[0216] Lf: Maximum depth of undulation;

[0217] Lg: The maximum diameter of the slope or undulation around the exposed (directly above) portion of the filler;

[0218] Lh: The maximum depth of the slope around the exposed portion of the filler;

[0219] Lt: Total thickness of the resin layer;

[0220] Lp: Minimum inter-packing distance at one end of the long side of the membrane containing the packing;

[0221] Lq: The minimum inter-packing distance at the other end that is more than 5m away from one end along the long side of the membrane;

[0222] Lmax: The maximum distance between packing materials;

[0223] Lmin: The minimum distance between packing materials.

Claims

1. A filler-containing membrane, which is a strip-shaped filler-containing membrane in which the filler is held in an adhesive resin layer such that the ratio of the distance Lb between the deepest part of the filler and the center of the tangential section between adjacent fillers to the average particle size D of the filler, i.e., the embedment ratio Lb / D, is 60% or more and 105% or less. The average particle size of the filler is 1–50 mm. μ m, The total thickness of the resin layer is more than 0.5 times and less than 2 times the average particle size of the filler. The ratio of the minimum inter-packing distance Lq to Lp at the other end, which is more than 5m away from the first end along the long side of the membrane containing the packing, is less than 1.

2. The packing is arranged in a hexagonal, square, or rhomboid grid. In any 10 or more locations randomly selected from the whole membrane, or in areas that reach more than 1% of the total membrane length, any packing material P0 is selected in each area, and three packing materials P1, P2, and P3 are selected in order of their closest distance to the packing material P0. Among the distances L1, L2, and L3 between these three packing materials P1, P2, and P3 and packing material P0, the ratio Lmax / Lmin of the maximum distance Lmax to the minimum distance Lmin is obtained. In the design, Lmax / Lmin is 1.

2. A filler-containing membrane, which is a strip-shaped filler-containing membrane in which the filler is held in the adhesive resin layer such that the ratio of the distance Lb between the deepest part of the filler and the center of the tangential section between adjacent fillers to the average particle size D of the filler, i.e., the embedment ratio Lb / D, is 60% or more and 105% or less. When the packing material is spherical, the average particle size is defined as its diameter. When the packing material is not spherical, the average particle size is defined, based on a planar or cross-sectional image of the packing membrane, as the maximum length or the diameter that mimics a spherical shape. In this definition, the average particle size is 1–50 mm. μ m, The total thickness of the resin layer is more than 0.5 times and less than 2 times the average particle size of the filler. In a region consisting of arbitrarily selected 10 or more locations from the entire membrane, or a region representing more than 1% of the total membrane length, an arbitrary packing material P0 is selected in each region. Then, three packing materials P1, P2, and P3 are selected in order of their closest distance to P0. Among the distances L1, L2, and L3 between these three packing materials P1, P2, and P3 and packing material P0, the average ratio of the maximum distance Lmax to the minimum distance Lmin (Lmax / Lmin) is between 1.0 and 1.

2. The packing material is arranged in a hexagonal, square, or rhomboid grid with Lmax / Lmin designed as 1.

3. The filler-containing membrane according to claim 1, wherein, When selecting any packing material P0 and selecting three packing materials P1, P2, and P3 in order of their closest distance to P0, the ratio of the maximum distance Lmax to the minimum distance Lmin among the distances L1, L2, and L3 between these three packing materials P1, P2, and P3 and the aforementioned packing material P0, is greater than 1.0 and less than 1.

2.

4. The filler-containing membrane according to claim 1 or 2, wherein, The membrane's area occupancy rate when viewed from above is 0.1% to 35%, and this area occupancy rate = packing density × average area of ​​one packing × 100.

5. The filler-containing membrane according to claim 1 or 2, wherein, The packing density is 30–72,000 pieces / mm². 2 .

6. The filler-containing membrane according to claim 1 or 2, wherein, The packing material is an inorganic packing material, an organic packing material, or a packing material in which organic and inorganic materials coexist.

7. The filler-containing membrane according to claim 1 or 2, wherein, The filler is a core of resin material particles coated with metal, i.e., metal-coated resin particles; a filler with insulating microparticles attached to the surface of conductive particles; or a filler whose surface of conductive particles has been insulated.

8. The filler-containing membrane according to claim 6, wherein, In addition to the fillers mentioned above, the membrane containing fillers also contains at least one of the following: filler, softener, accelerator, anti-aging agent, organic solvent, and ion scavenger.

9. The filler-containing membrane according to claim 6, wherein, In addition to the fillers mentioned above, the filler membrane also contains pigments and dyes as colorants.

10. The filler-containing membrane according to claim 1 or 2, wherein, The adhesive resin layer is laminated with the substrate film, and the thickness Le of the substrate film is 20. μ m or more and 100 μ Below m.

11. The filler-containing membrane of claim 10, wherein, The thickness Le of the substrate film is more than twice and less than 10 times the total thickness Lt of the resin layer.

12. The filler-containing membrane according to claim 1 or 2, wherein, The minimum melt viscosity of the adhesive resin layer is 1100 Pa·s or higher.

13. The filler-containing membrane according to claim 1 or 2, wherein, The minimum melt viscosity of the adhesive resin layer is above 2000 Pa·s.

14. The filler-containing membrane according to claim 1 or 2, wherein, The minimum melt viscosity of the adhesive resin layer is 3000~15000 Pa·s.

15. The filler-containing membrane according to claim 1 or 2, wherein, A second resin layer with a minimum melt viscosity lower than that of the adhesive resin layer is stacked on the adhesive resin layer. The total thickness of the resin layer, including the adhesive resin layer and the second resin layer, is more than 0.5 times and less than 2 times the average particle size of the filler.

16. The filler-containing membrane according to claim 1 or 2, wherein, The filler content is above 1.2 vol% and below 45 vol%.

17. The filler-containing membrane according to claim 1 or 2, wherein, The filler membrane has a width of 0.3 mm or more and 70 mm or less, and a length of 5 m or more and 5000 m or less; it is a roll wound around a core.

18. The filler-containing membrane of claim 17, wherein, With the core diameter set to 2R, in a region 2πR long from one end of the core containing the filler film, any filler P0 is selected, and three fillers P1, P2, and P3 are selected in order of their closest distance to filler P0. Among the distances L1, L2, and L3 between these three fillers P1, P2, and P3 and filler P0, the ratio Lmax / Lmin of the maximum distance Lmax to the minimum distance Lmin is calculated to be greater than 1.0 and less than 1.

2.

19. The filler-containing membrane according to claim 1 or 2, wherein, The filler is a conductive particle, and the filler-containing film is used as an anisotropic conductive film.

20. A membrane adhesive obtained by attaching a filler-containing membrane according to any one of claims 1 to 19 to an article.

21. A connecting structure obtained by connecting a first article and a second article via a filler-containing membrane as described in any one of claims 1 to 19.

22. The connection structure of claim 21, wherein the connection structure is obtained by anisotropically conductively connecting the first electronic component and the second electronic component via the filler-containing membrane of claim 9.

23. The connection structure according to claim 22, wherein, The combined height of the opposite terminals of the first electronic component and the second electronic component is less than twice the particle size of the filler containing the filler membrane.

24. A method for manufacturing a connecting structure, wherein a first article and a second article are pressed together via a filler-containing membrane as described in any one of claims 1 to 19.

25. A method for manufacturing a connecting structure, wherein anisotropic conductive connection is achieved by hot-pressing a first electronic component and a second electronic component via a filler-containing film as described in claim 19.

26. The manufacturing method according to claim 25, wherein, The combined height of the opposite terminals of the first electronic component and the second electronic component is set to be less than twice the particle size of the filler containing the filler membrane.

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