JP7315878B2 - Filler containing film - Google Patents

Description

The present invention relates to filler-containing films such as anisotropic conductive films.

Filler-containing films, in which fillers are dispersed in a resin layer, are used in a wide variety of applications such as matte films, capacitor films, optical films, label films, antistatic films, and anisotropic conductive films ( Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4).

As one aspect of filler-containing films, for example, anisotropic conductive films are widely used for mounting electronic components such as IC chips. From the viewpoint of adapting the anisotropic conductive film to a high mounting density, conductive particles are dispersed in the insulating resin layer of the anisotropic conductive film at a high density. However, if the number density of the conductive particles is too high, a short circuit is likely to occur in the connection structure between electronic components using the anisotropic conductive film.

On the other hand, in manufacturing an anisotropic conductive film, a coating roll having regular grooves on the surface such as a gravure coater is used to apply a resin liquid containing conductive particles to an insulating resin layer or a release film, A method of regularly arranging conductive particles in a single layer on an insulating resin layer has been proposed (Patent Document 5). In addition, the conductive particles dispersed in a predetermined arrangement are transferred to the first insulating resin layer and the second insulating resin layer using a transfer mold, and the first insulating resin and the second insulating resin to which the conductive particles are transferred are transferred to the first insulating resin layer and the second insulating resin layer. A method of forming a first conductive particle layer and a second conductive particle layer in which conductive particles are regularly arranged at different depths of an anisotropic conductive film by laminating resin has been proposed (Patent Document 6).

Japanese Unexamined Patent Application Publication No. 2006-15680 JP 2015-138904 A JP 2013-103368 A JP 2014-183266 A JP 2016-31888 JP 2015-201435 A

According to the production of the anisotropic conductive film described in Patent Document 5, since the conductive particles are regularly arranged, even if the number density of the conductive particles is increased, the number of short circuits is less than when the conductive particles are randomly arranged. less likely to occur. However, since the conductive particles are arranged in a single layer on one side of the anisotropic conductive film, there is a limit to precisely arranging the conductive particles so as not to cause short circuits when the number density is increased.

According to the method for producing an anisotropic conductive film described in Patent Document 6, since conductive particles are held in each of the first insulating resin layer and the second insulating resin layer, the anisotropic conductive film as a whole is conductive. It is possible to increase the number density of particles and suppress the occurrence of short circuits. However, according to the method for producing an anisotropic conductive film described herein, a curable resin is used for the first insulating resin layer and the second insulating resin layer, and the conductive particles are held in these resin layers by curing. , when the first insulating resin layer and the second insulating resin layer are bonded together, the tackiness of the surface of the anisotropic conductive film may decrease. The workability is lowered when the anisotropic conductive film is low-temperature pressure-bonded to the electronic component and temporarily pressure-bonded to fix it to the component.

In contrast, the present invention provides a filler-containing film such as an anisotropic conductive film by having a first filler layer and a second filler layer at different depths, thereby increasing the filler number density and enhancing functionality. An object of the present invention is to improve it (for example, to make it compatible with high-density mounting). Specifically, when the filler-containing film is configured as an anisotropic conductive film, it suppresses the occurrence of short circuits in the connection structure between electronic components, improves the connection reliability, and furthermore, the anisotropic conductive film, etc. In order to improve the workability in temporary attachment or temporary press-bonding of a filler-containing film, the film surface is provided with tackiness.

The present inventors have found that the first filler layer and the second filler layer are provided at different depths of the resin layer, thereby increasing the number density of the filler, and particularly an anisotropic conductive film, which is one aspect of the filler-containing film. When producing a filler-containing film that suppresses the occurrence of shorts in the case of, by pushing the filler into both the front and back surfaces of the resin layer, the first filler layer is exposed from one surface of the resin layer or the surface When the second filler layer is provided in the vicinity of the resin layer so as to be exposed from the other surface of the resin layer or provided in the vicinity of the surface, the conductive particles are likely to be captured by the terminals of the electronic component to be anisotropically connected, thereby improving the connection reliability. The present inventors have found that the tackiness of the film surface can be easily ensured, and have conceived the present invention. Thus, providing fillers on both sides can contribute to imparting and improving the performance of the filler-containing film, stabilizing the quality, and reducing the cost.

That is, the present invention comprises a resin layer, a first filler layer composed of a filler dispersed as a single layer in the resin layer, and a single layer dispersed in the resin layer at a depth different from that of the first filler layer. A filler-containing film comprising a filler-dispersed layer having a second filler layer made of a filler,
The filler of the first filler layer is exposed from one surface of the resin layer or is close to the one surface,
The filler in the second filler layer is exposed from or adjacent to the other surface of the resin layer to provide a filler-containing film. In particular, the present invention provides, as a preferred embodiment of the filler-containing film, a filler-containing film that is used as an anisotropic conductive film, in which the filler is conductive particles and the resin layer is an insulating resin layer.

The present invention also provides a method for producing the filler-containing film described above,
A filler is held on one surface of the resin layer in a predetermined dispersed state, the filler is pushed into the resin layer, another filler is held on the other surface of the resin layer in a predetermined divided state, and the filler is placed on the resin layer. To provide a manufacturing method characterized by pressing into.

In addition, the present invention provides a film stuck body in which the above filler-containing film is stuck to an article, a connected structure in which a first article and a second article are connected via the above filler-containing film, particularly and a connection structure in which a first electronic component and a second electronic component are anisotropically conductively connected via a filler-containing film used as an anisotropic conductive film. Furthermore, the present invention provides a method for manufacturing a connection structure in which the first article and the second article are pressure-bonded via the above-mentioned filler-containing film, and the first electronic component and the second electronic component, respectively. The first electronic component and the second electronic component are anisotropically conductively connected by thermocompression bonding the first electronic component and the second electronic component through a filler-containing film used as an anisotropic conductive film. A method of manufacturing a connection structure is provided.

According to the anisotropic conductive film, which is one aspect of the filler-containing film of the present invention, the filler is exposed from the front and back surfaces of the resin layer or is present in the vicinity of the surface, so that it is configured as an anisotropic conductive film. In this case, the conductive particles are likely to be captured by the terminals of the electronic component that are anisotropically connected. Therefore, connection reliability is improved.

In addition, the number density of the first filler layer and the number density of the second filler layer are lower than the number density of the filler in the entire film. Therefore, even if the filler is present at a high density in the entire film, it is possible to avoid the risk of lowering the tackiness of the film surface. Furthermore, according to the filler-containing film such as the anisotropic conductive film of the present invention, it is not essential to cure the resin layer in order to fix the filler to the resin layer, so that the tackiness is ensured on the film surface. can do. In addition to improving the tackiness, by providing the filler on both surfaces of the filler-containing film instead of only on one surface, it can be expected to impart a different functionality than when only one surface is provided with the filler.

In addition, since the number density of the first filler layer and the number density of the second filler layer are lower than the number density of the fillers in the entire film, the arrangement of the fillers in each filler layer can be precisely controlled. Therefore, the fillers can be accurately arranged in a predetermined arrangement even if the arrangement pitch of the fillers in the entire filler-containing film such as an anisotropic conductive film is narrowed. Therefore, together with the above-described improvement in trapping property, it is suitable for fine-pitch connection, and can be used, for example, for connection of electronic components having a terminal width of 6 μm to 50 μm and an inter-terminal space of 6 μm to 50 μm. Also, if the effective connection terminal width (the width of the portion of the pair of terminals that face each other when connected, the width of the portion that overlaps in plan view) is 3 μm or more and the shortest distance between the terminals is 3 μm or more, no short circuit will occur. Electronic components can be connected. In addition, as another aspect, for example, there is an optical film, and the optical performance of the filler can be adjusted by adjusting the non-contact and independent number ratio in the thickness direction and planar view of the resin layer of the filler. . The same can be said for materials that are directly related to the appearance, such as matte films. Since this can be adjusted on both sides, it is easy to contribute to improvement in performance and quality and cost reduction.

FIG. 1A is a plan view showing the arrangement of fillers (conductive particles) in a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10A of an example. FIG. 1B is a cross-sectional view of a filler-containing film 10A of an example. FIG. 2 is a cross-sectional view of a filler-containing film in which the filling ratio of the filler in the first filler layer and the filler in the second filler layer is approximately 100%, and the filler is exposed from the surface of the resin layer. FIG. 3 shows a filler-containing film in which the filling rate of the filler in the first filler layer and the filler in the second filler layer is about 100%, and the filler is embedded in the resin layer so that the surface of the resin layer is flat. It is a sectional view. FIG. 4 is a cross-sectional view of a filler-containing film in which the filling rate of the filler slightly exceeds 100% and the surface of the resin layer directly above the filler has depressions. FIG. 5A is a plan view showing the arrangement of fillers (conductive particles) in a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10B of Example. FIG. 5B is a cross-sectional view of the filler-containing film 10B of the example. FIG. 6 is a cross-sectional view when an electronic component is anisotropically conductively connected with the filler-containing film 10A. FIG. 7A is a plan view showing the arrangement of fillers (conductive particles) in a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10C of Example. FIG. 7B is a cross-sectional view of a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10C of Example. FIG. 8A is a plan view showing the arrangement of fillers (conductive particles) in a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10D of Example. FIG. 8B is a cross-sectional view of the filler-containing film 10D of the example. FIG. 9 is a plan view showing the arrangement of filler units 1C before and after anisotropic conductive connection. FIG. 10 is a cross-sectional view of a connected structure in which electronic components are anisotropically conductively connected using a filler-containing film 10D. FIG. 11A is a cross-sectional view of a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10E having a second resin layer. FIG. 11B is a cross-sectional view of a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10F having a second resin layer. FIG. 11C is a cross-sectional view of a filler-containing film (an anisotropic conductive film that is one aspect thereof) 10G having a second resin layer. FIG. 12 is a process explanatory diagram of a method for manufacturing a filler-containing film (an anisotropic conductive film, which is one aspect thereof) 10 having a second resin layer.

Hereinafter, the filler-containing film of the present invention will be described in detail with reference to the drawings, mainly focusing on an anisotropic conductive film which is one embodiment thereof. In addition, in each figure, the same code|symbol represents the same or equivalent component.

<Overall structure of filler-containing film>
FIG. 1A is a plan view for explaining the arrangement of fillers in a filler-containing film 10A of one example of the present invention, and FIG. 1B is its XX cross-sectional view.

The filler-containing film 10A includes a resin layer 2, a first filler layer composed of a filler 1A dispersed in a single layer at a predetermined depth in the film thickness direction from one surface 2a of the resin layer 2, and a first filler. It consists of a filler dispersed layer 3 formed of a second filler layer composed of filler 1B dispersed in a single layer at a depth different from that of the layer. The filler 1A of the first filler layer is unevenly distributed on one surface 2a side of the resin layer 2 and exposed from the surface 2a, and the filler 1B of the second filler layer is located on the other surface 2b side of the resin layer 2. and exposed from the surface 2b. In the drawing, the fillers 1A in the first filler layer are shown in dark color, and the fillers in the second filler layer are shown in white.

In addition, unless otherwise specified, the dispersed state of the fillers in the present invention includes the state in which the fillers 1A and 1B are randomly dispersed and the state in which the fillers 1B are dispersed in a regular arrangement.

In addition, in the filler-containing film 10A of this example, one of the number density of the fillers 1A in the first filler layer and the number density of the fillers 1B in the second filler layer gradually increases in the longitudinal direction of the film, and the other gradually decreases. The uniformity of the number density of the fillers 1A and 1B, which are the sum of the first filler layer and the second filler layer, over the entire film is excellent.

<Filler>
Fillers 1A and 1B are known inorganic fillers (metals, metal oxides, metal nitrides, etc.), organic fillers (resin particles, rubber particles, etc.), organic materials and inorganic fillers, depending on the application of the filler-containing film. Fillers mixed with a system material (for example, particles whose core is made of a resin material and whose surface is plated with metal (metal-coated resin particles), conductive particles with insulating fine particles attached to the surface, conductive particle surfaces , etc.), depending on the performance required for the application, such as hardness and optical performance. For example, in optical films and matte films, silica fillers, titanium oxide fillers, styrene fillers, acrylic fillers, melamine fillers and various titanates can be used. 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 in capacitor films etc. can be used. The adhesive film may contain polymer rubber particles, silicone rubber particles, and the like. The anisotropic conductive film contains conductive particles. 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 having insulating fine particles attached to their surfaces. . Two or more types can also be used together. Among them, the metal-coated resin particles are preferable because the resin particles repel each other after being connected, thereby making it easy to maintain contact with the terminal and stabilizing the conduction performance. Moreover, the surfaces of the conductive particles may be subjected to an insulating treatment by a known technique so as not to interfere with the conductive properties. The fillers listed above for each use are not limited to the use concerned, and may be contained in filler-containing films for other uses as necessary. Moreover, in the filler-containing film for each application, two or more fillers can be used in combination, if necessary.

The shape of the filler is appropriately selected from spherical, ellipsoidal, columnar, acicular, combinations thereof, and the like depending on the use of the filler-containing film. A spherical shape is preferable because it facilitates confirmation of the filler arrangement and facilitates maintenance of a uniform shape. In particular, when the filler-containing film is configured as an anisotropic conductive film, it is preferable that the conductive particles, which are the filler, are substantially spherical. By using substantially spherical conductive particles, for example, in producing an anisotropic conductive film in which conductive particles are arranged using a transfer mold as described in Japanese Patent Application Laid-Open No. 2014-60150, transfer Since the conductive particles roll smoothly on the mold, the conductive particles can be filled at a predetermined position on the transfer mold with high accuracy. Therefore, the conductive particles can be precisely arranged.

The particle diameters DA and DB of the fillers 1A and 1B are preferably 1 μm or more and 30 μm or less in order to cope with variations in wiring height, suppress an increase in conduction resistance, and suppress the occurrence of short circuits. It is more preferably 3 μm or more and 9 μm or less.

The particle size of the filler 1A in the first filler layer and the particle size of the filler 1B in the second filler layer may be the same or different. When the filler-containing film is configured as an anisotropic conductive film, the compressed state such as flatness after anisotropically conductive connection of both fillers 1A and 1B, which are conductive particles, especially when the conductive particles are metal-coated resin particles It is preferable to make them the same from the point of stabilizing the conduction performance by making the compression state of them the same. Further, the filler 1A and the filler 1B may be the same or different in material and hardness (for example, compression elastic modulus).

The particle sizes of the fillers 1A and 1B can be measured with a general particle size distribution measuring device, and the average particle size can also be determined using a particle size distribution measuring device. An example of a measuring device is FPIA-3000 (Malvern). The diameter of the filler in the film can be obtained from observation with a metallurgical microscope or observation with an electron microscope such as SEM. In this case, it is desirable to set the number of samples for measuring the filler diameter to 200 or more. When the shape of the filler is not spherical, the particle size of the filler can be the maximum length or the diameter of a sphere-like shape based on the plane image or cross-sectional image of the filler-containing film.

<Position of filler in film thickness direction>
Regarding the positions of the fillers 1A and 1B in the film thickness direction, in FIG. However, in the present invention, the filler 1A of the first filler layer is exposed from one surface 2a of the resin layer 2, or the filler 1A is completely embedded in the resin layer 2. However, it is located close to the surface 2a of the resin layer 2, and the filler 1B of the second filler layer is exposed from the other surface 2b of the resin layer 2, or the second filler 1B is inside the resin layer 2. It includes an aspect in which it is completely embedded but is located close to the surface 2 b of the resin layer 2 . Here, the fillers 1A and 1B are completely embedded in the resin layer 2, but are located near the surfaces 2a and 2b. This means that the embedding rate is 110% or less, preferably 105% or less. When the fillers 1A and 1B are exposed from the surfaces 2a and 2b of the resin layer 2, the particle sizes of the fillers 1B in the filler layer may be the same or different. When the filler-containing film is configured as an anisotropic conductive film, it is preferable because the ability to capture the fillers 1A and 1B, which are conductive particles, is remarkably improved at the time of anisotropic conductive connection. In addition, when the fillers 1A and 1B are embedded in the resin layer 2 and are close to the surfaces 2a and 2b thereof, the tackiness of the filler-containing film is improved without impairing the trapping properties of the fillers 1A and 1B. It is preferable because In particular, when the fillers 1A and 1B are close to the surfaces 2a and 2b of the resin layer 2 by less than 0.1 μm, the tackiness is not impaired and the catching properties of the fillers 1A and 1B are improved, which is preferable. In a filler layer having a filler number density of 5000/mm ² or more or an area occupation ratio of 2% or more, the fillers 1A and 1B are embedded in the resin layer 2, and the surfaces 2a and 2b of the resin layer 2 are substantially the same. It is preferably flush. As a result, compared to the case where the filler is exposed from the resin layer, the tackiness of the filler-containing film does not decrease, and the embedding rate exceeds 100% and the filler is completely embedded. When the filler-containing film is configured as an anisotropic conductive film, the filler, which is a conductive particle, is less likely to be affected by resin flow during anisotropic conductive connection, thereby improving capture properties. On the other hand, if neither the first filler layer nor the second filler layer is exposed from the resin layer 2 and neither is positioned near the surfaces 2a and 2b of the resin layer 2, the filler-containing film will be anisotropic. When it is configured as a conductive film, the filler, which is a conductive particle, is likely to be affected by resin flow during anisotropic conductive connection, and there is concern about a decrease in trapping ability. Alternatively, it may be difficult to uniformly remove the resin from the vicinity of the filler, which may adversely affect the pushing of the filler. The same applies to filler-containing films other than anisotropic conductive films.

The distance from the tangential plane of the surface 2a of the resin layer 2 to the deepest part of the filler 1A in the intermediate part between the fillers 1A adjacent in the first filler layer (hereinafter referred to as the embedding amount) L1 and the particle diameter DA of the conductive particles 1A (L/DA) is preferably 30% to 110%, more preferably 30% to 105%, still more preferably 30% to 100%, and particularly preferably 60% or more. 100% or less. Similarly, for the filler 1B of the second filler layer, the distance (embedding amount) L2 from the tangential plane of the surface 2b of the resin layer 2 at the intermediate portion between the adjacent fillers 1B to the deepest portion of the filler 1B and the The embedding rate, which is the ratio (L2/DB) to the particle diameter DB, is preferably 30% or more and 110% or less, more preferably 30% or more and 105% or less, still more preferably 30% or more and 100% or less, and particularly preferably It is 60% or more and 100% or less. By setting the embedding ratios (L1/DA) and (L2/DB) to 30% or more, it becomes easy to maintain the fillers 1A and 1B in a predetermined regular arrangement or a predetermined arrangement by means of the resin layer 2. Further, by making the filler-containing film 110% or less, preferably 105% or less, when the filler-containing film is configured as an anisotropic conductive film, the filler, which is a conductive particle between the terminals, is unnecessary due to the flow of the resin during anisotropic conductive connection. It becomes difficult to be swept away by In addition, in the filler-containing film, by aligning the embedding rate of the filler from the resin layer 2, an effect of improving the properties can be expected. As an example, when the performance of an optical film depends on a filler, if there is a certain degree of regularity in the dispersibility (independence) in plan view and the embedding state, it can be obtained by simply applying a kneaded binder. It is presumed that performance improvement and quality stability can be obtained compared to other methods.

The embedding rate of the fillers 1A in the first filler layer and the embedding rate of the fillers 1B in the second filler layer may be the same or different.

Here, the filler diameters DA and DB are the average filler diameters of the fillers 1A in the first filler layer and the fillers 1B in the second filler layer, respectively.

Further, in the present invention, the numerical values of the embedding ratio (L1/DA) and (L2/DB) are 80% or more of the total number of fillers (e.g. conductive particles) contained in the filler-containing film such as an anisotropic conductive film, Preferably, 90% or more, more preferably 96% or more, have the values of the embedding ratios (L1/DA) and (L2/DB). Embedding ratios (L1/DA) and (L2/DB) are determined by arbitrarily extracting 10 or more regions with an area of 30 mm ² or more from a filler-containing film such as an anisotropic conductive film, and observing a part of the cross section of the film with an SEM. It can be obtained by imaging and measuring a total of 50 or more fillers. In order to further improve the accuracy, 200 or more fillers may be measured and obtained.

As an example of a particularly preferable embedding mode of the fillers 1A and 1B in the resin layer 2, as shown in FIG. are exposed from the surfaces 2a and 2b of the resin layer 2, respectively, and recesses 2x are formed in the filler resin layer 2 around the exposed fillers 1A and 1B. The fillers 1A and 1B on the front and back of the resin layer 2 are flush with the surfaces 2a and 2b of the resin layer 2, respectively. A mode in which recesses 2x are formed in the resin layer 2 around the exposed fillers 1A and 1B exposed from the surfaces 2a and 2b can be mentioned. Due to the formation of the recesses 2x, when the filler-containing film is configured as an anisotropic conductive film, the filler 1A generated when the fillers 1A and 1B, which are conductive particles, are sandwiched between the terminals during anisotropic conductive connection. , 1B, the resistance received from the resin is reduced compared to the case where there is no recess 2x, and the ability to capture the filler in the terminal is improved. As a filler-containing film, compared to a film obtained by simply applying a kneaded binder, as described above, the state of the filler and resin has specificity, so it is expected that performance and quality will be characterized. can be expected.

On the other hand, when the filler-containing film is configured as an anisotropic conductive film, when connecting electronic components using the anisotropic conductive film, from the viewpoint of preventing air from being caught, as shown in FIG. Moreover, it is preferable that the filling ratio of the fillers 1A and 1B, which are conductive particles, is about 100% and that the fillers 1A and 1B are embedded in the resin layer 2 so that the surface of the filler dispersed layer 3 is flat.

Further, when the embedding rate exceeds 100%, as shown in FIG. 4, depressions 2y are formed in the regions directly above the fillers 1A and 1B on the surfaces 2a and 2b of the resin layer 2 close to the fillers 1A and 1B. preferably. Due to the formation of the recesses 2y, when the filler-containing film is configured as an anisotropic conductive film, the pressure during the anisotropic conductive connection is greater than the case where the recesses 2y are not formed. It becomes easy to concentrate on 1B, and the catching property of the fillers 1A and 1B in the terminal is improved. As a filler-containing film, compared to a film obtained by simply applying a kneaded binder, as described above, the state of the filler and resin has specificity, so it is expected that performance and quality will be characterized. can be expected.

<Filler arrangement>
In the filler-containing film 10A shown in FIG. 1A, the fillers 1A in the first filler layer and the fillers 1B in the second filler layer are arranged in a square lattice. As described above, in the filler-containing film of the present invention, the fillers 1A and 1B are preferably arranged regularly. As for the regular arrangement, in addition to the square lattice shown in FIG. 1A, lattice arrangements such as a rectangular lattice, an orthorhombic lattice, and a hexagonal lattice can be used. As a regular arrangement other than the lattice arrangement, there can be mentioned one in which particle rows in which fillers are linearly arranged at predetermined intervals are arranged side by side at predetermined intervals. When the filler-containing film is configured as an anisotropic conductive film by arranging the fillers 1A and 1B in a regular arrangement such as a lattice, pressure is applied to each of the fillers 1A and 1B, which are conductive particles, during anisotropic conductive connection. In addition, variations in conduction resistance can be reduced.

The arrangement of the fillers 1A in the first filler layer and the arrangement of the fillers 1B in the second filler layer may be the same or different. When they are the same, for example, like the filler-containing film 10B shown in FIGS. A filler unit may be formed in which the fillers 1A of the first filler layer and the fillers 1B of the second filler layer are in contact with each other or close to each other. In that case, it is preferable that the filler units are arranged regularly without contacting each other. Thereby, the occurrence of short circuit can be suppressed.

For example, the arrangement of the fillers 1A and 1B is the same in the first filler layer and the second filler layer, but the arrangement of one filler 1A is shifted from the arrangement of the other filler 1B by a predetermined distance in the film surface direction. , a filler unit can be configured in which the filler 1A of the first filler layer and the filler 1B of the second filler layer are partially overlapped in plan view of the filler-containing film. In this case, like the anisotropic conductive film, which is one aspect of the filler-containing film 10A shown in FIG. Since the containing film is an anisotropic conductive film, an effect that either of the fillers 1A and 1B, which are conductive particles, is likely to be captured by the terminal during anisotropic conductive connection can be expected. That is, when an anisotropic conductive connection is made between the terminal 20 of the first electronic component 30 and the terminal 21 of the second electronic component 31 using an anisotropic conductive film, which is one aspect of the filler-containing film 10A shown in FIG. 1A. 6, when the filler 1A is positioned at the edges of the terminals 20 and 21 as shown in FIG. Even if the fillers 1A or 1B are displaced when pressed, the terminals 20 and 21 are connected to one of the adjacent fillers 1A and 1B, and the ability to capture the fillers at the terminals can be enhanced. Further, in this case, if resin flow occurs during heating and pressurization, the distance between the fillers 1A and 1B is increased, so the risk of short-circuiting is reduced. It should be noted that partially overlapping the fillers 1A and 1B in this way is a filler diameter and number density in the entire anisotropic conductive film, which is one aspect of the filler-containing film, the distance between the fillers, the size of the terminals to be connected, and the terminals. Based on the distance between fillers 1A and 1B, it is assumed that a short circuit will not occur in the design even if the fillers 1A and 1B are partially overlapped. It is preferable because the effect of improving the properties is likely to be satisfied. Further, when the adjacent fillers 1A and 1B are substantially flush with the front and back surfaces 2a and 2b of the resin layer 2, respectively, or are exposed from the front and back surfaces 2a and 2b, these is preferable because the effect of is further increased. When the filler-containing film is configured as an anisotropic conductive film in this way, in the above-mentioned filler-containing film, if the filler 1A of the first filler layer and the filler 1B of the second filler layer are completely Even if they are overlapped, if they are used for anisotropic conductive connection, the resin may melt or flow due to heat and pressure during anisotropic conductive connection. No problem. The same can be said for aspects other than the anisotropic conductive film.

On the other hand, when the arrangement of the fillers 1A in the first filler layer and the arrangement of the fillers 1B in the second filler layer are different, the arrangements have a common point, for example, the shapes of both arrangements are similar. Preferably. This is not limited to anisotropic conductive films.

Further, the arrangement of the filler 1A and the arrangement of the filler 1B are each part of the regular arrangement, and the arrangement of the filler 1A and the arrangement of the filler 1B are combined to form a regular arrangement such as a lattice. good too. For example, when the arrangement of the filler 1A and the arrangement of the filler 1B together form a hexagonal lattice, the arrangement of the filler 1A has a hexagonal arrangement included in the hexagonal lattice, and the arrangement of the filler 1B has the hexagonal arrangement. Let the array be the center of Note that the regular arrangement in this case is not limited to a hexagonal lattice. Moreover, it is not limited about which part of the regular arrangement|sequence formed by combining both the arrangement|sequence of the filler 1A, and the arrangement|sequence of the filler 1B makes. The regular arrangement formed by combining the arrangement of the fillers 1A and the arrangement of the fillers 1B may be distorted with respect to the correct lattice arrangement. Such arrangement conditions, which are difficult to reproduce easily, make it possible to manage lots, and it is also possible to provide traceability (a property that enables tracing) to filler-containing films and connected structures using them. becomes. This is also effective for prevention of counterfeiting of filler-containing films and connection structures using such films, determination of authenticity, prevention of unauthorized use, and the like. Generally, in an anisotropic conductive connection, a situation may occur in which a considerable number of conductive particles arranged linearly are not captured by the edge portion of the terminal. situation can be avoided. Therefore, it is possible to easily keep the number of the conductive particles trapped in the terminal within a certain range, which is preferable. In addition, since such distortion is repeated, it is possible to easily judge whether the arrangement shape is appropriate or not by a sampling inspection or the like.

The distorted arrangement of fillers as described above can be formed using a single transfer mold. may be formed. By forming an arrangement of fillers (e.g., conductive particles) as an entire filler-containing film such as an anisotropic conductive film using two transfer molds, a transfer mold for filler 1A and a transfer mold for filler 1B, various It is possible to form an arrangement of , which makes it easier to respond to design changes in a short period of time, contributes to the reduction of manufacturing costs, and furthermore, fillers such as various anisotropic conductive films with different filler arrangements It is possible to reduce the total cost related to the production of a filler-containing film such as an anisotropic conductive film, including the costs required for the possession of manufacturing equipment for producing the containing film, parts management, maintenance, and the like. In the present invention, as described above, two types of transfer molds, the transfer mold for filler 1A and the transfer mold for filler 1B, are used to form a filler-containing film such as an anisotropic conductive film as a whole in plan view. ), and a method for manufacturing a filler-containing film such as an anisotropic conductive film using two transfer dies according to the design method.

In addition, the filler 1A and the filler 1B may have voids in the arrangement state within the range where the intended effect of the invention of the filler-containing film can be obtained. It can be confirmed by regularly existing in a predetermined direction of the film. Further, by causing the missing filler to repeatedly exist in the longitudinal direction of the film, or by gradually increasing or decreasing the locations where the filler is missing in the longitudinal direction of the film, the same effect as the distortion described above can be obtained. That is, lot management becomes possible, and traceability (property that enables tracing) can be imparted to the filler-containing film and the connection structure using the same. This is also effective for prevention of counterfeiting of filler-containing films and connection structures using such films, determination of authenticity, prevention of unauthorized use, and the like.

In each of the first filler layer and the second filler layer, the lattice axis or arrangement axis of the arrangement of the fillers 1A and 1B may be parallel to the longitudinal direction of the filler-containing film 10A such as an anisotropic conductive film. It may intersect the longitudinal direction of the filler-containing film 10A such as a conductive film. For example, in the case of using an anisotropic conductive film, there is no particular limitation because it can be determined according to the width of terminals to be connected, the pitch of terminals, and the like. For example, when making an anisotropic conductive film for fine pitch, as shown in FIG. The angle θ between the longitudinal direction (the lateral direction of the film) of the terminal 20 connected with the filler-containing film 10A such as an anisotropic conductive film and the lattice axis A is preferably 6° to 84°, More preferably, it is 11° to 74°. Even in applications other than the anisotropic conductive film, such an inclination is expected to have the effect of stabilizing the trapped state.

The inter-particle distance of the fillers 1A and 1B is appropriately determined depending on whether or not the filler (eg, conductive particles) unit 1C is formed, the size of the terminals connected by the filler-containing film such as an anisotropic conductive film, the terminal pitch, and the like. For example, the nearest inter-particle distance L3 between adjacent fillers 1A in the first filler layer and the nearest inter-particle distance L4 between adjacent fillers 1B in the second filler layer (FIG. 1A) are the anisotropic conductive film. In the case of, when the adjacent conductive particles 1A and 1B do not belong to one filler unit (conductive particle unit), the particle diameters DA and DB of the fillers 1A and 1B are 1.5 times or more. is preferable from the viewpoint of short-circuit suppression, and 66 times or less is preferable in terms of securing the minimum number of fillers trapped in the terminal and obtaining stable conduction. In particular, when the filler-containing film is configured as an anisotropic conductive film, and when the anisotropic conductive film is adapted to fine-pitch COG (Chip On Glass), the distances L3 and L4 between the closest particles are 1.5 times the particle diameter. It is preferably 5 to 5 times larger, and preferably 10 to 66 times larger than the particle diameter in the case of FOG (Film On Glass) having a relatively large pitch. Other than the anisotropic conductive film, it may be appropriately adjusted according to the characteristics thereof.

As described later, when forming a filler unit 1C with a plurality of fillers 1A in the first filler layer, or when forming a filler unit 1C with a plurality of fillers 1B in the second filler layer, a filler-containing film In the case of an anisotropic conductive film, which is one embodiment, the distance between the fillers 1A in the first filler layer in one fire unit 1C is preferably 1/4 times or less the particle diameter DA of the filler 1A. , the fillers 1A may be in contact with each other. Similarly, the distance between the fillers 1B in the second filler layer in one filler unit 1C is preferably 1/4 times or less the particle diameter DB of the fillers 1B, and the fillers 1B may be in contact with each other. Other than the anisotropic conductive film, it may be appropriately adjusted according to the characteristics thereof.

<Filler number density>
The number density of the filler in the entire filler-containing film of the present invention is not particularly limited because it is appropriately adjusted according to the application, the required properties, the particle size of the fillers 1A and 1B, the arrangement, etc. However, the following anisotropic The case of conductive films can be applied. Since the production conditions for the filler-containing film are approximately the same as those for the anisotropic conductive film, it can be safely assumed that the conditions for the filler number density are also approximately the same. When the filler-containing film is configured as an anisotropic conductive film, the pitch of the terminals in the electronic component connected with the anisotropic conductive film, the particle diameter and arrangement of the fillers (conductive particles) 1A and 1B in the anisotropic conductive film, etc. adjusted accordingly. For example, the upper limit of the number density is preferably 70,000/mm ² or less, more preferably 50,000/mm ² or less, and even more preferably 35,000/mm ² or less in order to suppress short circuits. On the other hand, the lower limit of the number density is preferably 100/mm ² or more, preferably 150/mm ² or more, and 400 in order to reduce the filler (conductive particles) for cost reduction and to satisfy the conductivity performance. pcs/mm ² or more is even more preferred. In particular, when the anisotropic conductive film is used for fine-pitch applications in which the minimum connection area of terminals of electronic components is 2000 μm ² or less, the number is preferably 10,000/mm ² or more. The design number density of the fillers 1A in the first filler layer and the design number density of the fillers 1B in the second filler layer may be the same or different.

In the production of a filler-containing film, when the filler is attached in the longitudinal direction of the filler-containing film, if there is a tendency for the lack of filler or non-uniformity in distribution to increase inevitably, the longitudinal direction of the filler-containing film One of the number density of the fillers in the first filler layer and the number density of the fillers in the second filler layer gradually increases in the direction, and the other gradually decreases, that is, the direction of increase or decrease in the number density is the first It is preferable that the first filler layer and the second filler layer have opposite directions. When the average number density of the first filler in the entire filler-containing film such as an anisotropic conductive film is made equal, by gradually increasing or decreasing the number density of the filler as described above, one end 10Ap of the filler-containing film and the other end 10Aq, the magnitude relationship between the number density of the first filler layer and the number density of the second filler layer is reversed, and the uniformity of the filler number density in the entire filler-containing film is improved. This can be expected to be effective in the case where uniformity in the number density over the entire surface is strongly required, as in an anisotropic conductive film, since the degree of manufacturing difficulty is reduced. In addition, the effect of cost reduction can be similarly expected for the anisotropic conductive film and for other uses.

The number density of the filler in the first filler layer or the second filler layer in the longitudinal direction of the filler-containing film such as an anisotropic conductive film is within a region of 20% or more of the total length of the film or 3 m or more in the longitudinal direction of the filler-containing film. In, as the measurement area of the filler number density, a plurality of rectangular areas with one side of 100 μm or more are set at different positions in the longitudinal direction of the filler-containing film (preferably 5 or more, more preferably 10 or more), and the measurement is performed. The total area of the regions is preferably 2 mm ² or more, and the number density of the filler in each measurement region is measured using a metallographic microscope and averaged, or the region of 20% or more of the total length of the film or 3 m or more It can be obtained by taking an image inside and measuring the number density of the filler with image analysis software (e.g., WinROOF, Mitani Shoji Co., Ltd.), and the number density of the filler gradually increases or decreases. can be confirmed by the fact that the filler number density measured in each measurement region monotonically increases or decreases with respect to the longitudinal direction of the filler-containing film such as an anisotropic conductive film. The area of 100 μm×100 μm is an area in which one or more bumps exist in the object to be connected with an inter-bump space of 50 μm or less. In addition, the upper limit of one side of the measurement area may be appropriately adjusted depending on the number density of the filler. If it is extremely dense or sparse, for example, the total number of fillers in the total area may be adjusted to 200 or more, preferably 1000 or more.

When the filler-containing film is configured as an anisotropic conductive film, the anisotropic conductive film is used for fine-pitch applications in which the minimum terminal connection area of the electronic component connected with the anisotropic conductive film is 2000 μm ² or less. In addition, at one end 10Ap of the filler-containing film (anisotropic conductive film), the number density NpAB of the fillers 1A and 1B, which is the combination of the first filler layer and the second filler layer, and the first filler layer and the second filler layer at the other end 10Aq The difference (NpAB-NqAB) from the number density NqAB of the fillers 1A and 1B combined with the filler layers is preferably within ±2%, more preferably ±1.5, with respect to their average ((NpAB + NqAB)/2). %, still more preferably within ±1%, and in the case of a normal pitch with a minimum terminal contact area exceeding 2000 μm ² , (NpAB-NqAB) is preferably ((NpAB+NqAB)/2) It is within ±20%, more preferably within ±10%.

When the designed filler arrangement and number density are equal in the first filler layer and the second filler layer, the step of forming the first filler layer and the second filler layer in the resin layer 2 includes the first filler layer and the second filler layer as described later. The running direction of the resin layer 2 can be reversed between when the filler 1A that forms the filler layer is attached to the resin layer 2 and when the filler 1B that forms the second filler layer is attached to the resin layer 2, and the same process can be repeated. It is preferable for manufacturing. Reversing the running direction in this way means that if there is a defect in the transfer mold used for attaching the filler, the position of the defect on the filler-containing film such as an anisotropic conductive film will not overlap on the front and back of the film. It is also preferable in that the risk of the film becoming defective as a whole can be avoided.

On the other hand, when the number densities of the fillers 1A and 1B in the first filler layer and the second filler layer are different, the filler layer with the higher number density among these is brought closer to the outer interface of the filler-containing film such as an anisotropic conductive film. Positioning is preferable from the viewpoint of enhancing the ability of the terminal to capture the filler. In addition, when the filler layer is exposed on the outer surface of the filler-containing film such as an anisotropic conductive film, the number of filler layers to be exposed is limited from the viewpoint of suppressing the decrease in tackiness of the filler-containing film such as an anisotropic conductive film. It is preferable to use a low density one (lower number density side). As described above, in the filler-containing film, the number density of the fillers 1A and 1B in the first filler layer and the second filler layer can be appropriately varied depending on the required properties.

<Resin layer>
(Viscosity of resin layer)
The minimum melt viscosity of the resin layer 2 is not particularly limited, and can be appropriately determined according to the use of the filler-containing film, the production method of the filler-containing film, and the like. For example, as long as the recesses 2x and 2y described above can be formed, it can be about 1000 Pa·s depending on the manufacturing method of the filler-containing film. On the other hand, when a filler is held in a predetermined arrangement on the surface of a resin layer and the filler is pushed into the resin layer as a method for producing a filler-containing film, the resin layer has a minimum content of resin from the viewpoint that the film can be formed. It is preferable to set the melt viscosity to 1100 Pa·s or more. The depressions 2x, 2y may be on both sides or only on one side (ie, either one of the fillers 1A, 1B).

Further, as will be described later in the method of manufacturing a filler-containing film, depressions 2x are formed around the exposed portions of the fillers 1A and 1B pressed into the resin layer 2 as shown in FIG. 1B, or as shown in FIG. preferably 1500 Pa s or more, more preferably 2000 Pa s or more, still more preferably 3000 to 15000 Pa s, and even more It is preferably 3000 to 10000 Pa·s. This minimum melt viscosity can be obtained by using a rotary rheometer (manufactured by TA Instruments) as an example, holding a measuring pressure of 5 g constant, and using a measuring plate with a diameter of 8 mm. More specifically, the temperature range At 30 to 200° C., it can be obtained by setting the temperature increase rate to 10° C./min, the measurement frequency to 10 Hz, and the load variation to the measurement plate to 5 g.

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

Further, when the filler dispersion layer 3 of the filler-containing film 10A is formed by pressing the fillers 1A and 1B into the resin layer 2, the resin layer 2 when the fillers 1A and 1B are pressed is When the fillers 1A and 1B are pushed into the resin layer 2 so that the fillers 1A and 1B are exposed, the resin layer 2 is plastically deformed to form a depression 2x (FIG. 1B) in the resin layer 2 around the fillers 1A and 1B. When the fillers 1A and 1B are pressed into the resin layer 2 so that the fillers 1A and 1B are embedded in the resin layer 2 without being exposed from the resin layer 2, the resin layer immediately above the fillers 1A and 1B is formed into a viscous body having a high viscosity. A viscous body having such a high viscosity that a recess 2y (FIG. 4) is formed on the surface of 2 is used. Therefore, the lower limit of the viscosity of the resin layer 2 at 60° C. is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, and still more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less. It is preferably 15000 Pa·s or less, more preferably 10000 Pa·s or less. This measurement is performed in the same manner as for the minimum melt viscosity, and can be obtained by extracting the value at a temperature of 60°C.

The specific viscosity of the resin layer 2 when the fillers 1A and 1B are pushed into the resin layer 2 depends on the shape and depth of the recesses 2x and 2y to be formed, and the lower limit is preferably 3000 Pa s or more, more preferably is 4000 Pa·s or more, more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, still more preferably 10000 Pa·s or less. Also, such a viscosity is preferably obtained at 40-80°C, more preferably 50-60°C.

As described above, since the recesses 2x (FIG. 1B) are formed around the fillers 1A and 1B exposed from the resin layer 2, flattening of the fillers 1A and 1B that occurs when the filler-containing film is pressed onto the article. The resistance received from the resin against deformation is reduced as compared with the case where there is no recess 2x. Therefore, when the filler-containing film is an anisotropic conductive film, the conductive particles are easily sandwiched between the terminals during the anisotropic conductive connection, thereby improving the conduction performance and the capture property. In particular, in an anisotropic conductive film, fillers 1A and 1B, which are conductive particles, are present on both sides of the resin layer 2. Therefore, in order to reduce the resistance received from the resin, such depressions 2x are formed on either side of the film. It is preferably on one side, more preferably on both sides.

In addition, since the dents 2y (FIG. 4) are formed on the surface of the resin layer 2 directly above the fillers 1A and 1B that are embedded without being exposed from the resin layer 2, the filler is more likely than the case without the dents 2y. The pressure when the containing film is pressure-bonded to the article tends to be concentrated on the fillers 1A and 1B. Therefore, when the filler-containing film is an anisotropic conductive film, the conductive particles are easily sandwiched between the terminals during the anisotropic conductive connection, thereby improving the trapping property and the conduction performance. In particular, in an anisotropic conductive film, for the same reason as described above, it is preferable that such depressions 2y are present on either one surface, and more preferably on both surfaces. 2x and 2y may be present on each side or may be mixed.

<“Tilted” or “undulating” instead of dents>
The 'dents' 2x, 2y of the filler-containing film as shown in Figures 1B and 4 can also be described in terms of 'tilts' or 'undulations'. Description will be made below with reference to the drawings.

A filler-containing film 10A such as an anisotropic conductive film is composed of a filler-dispersed layer 3 (FIG. 1B). In the filler-dispersed layer 3, the fillers 1A and 1B are regularly dispersed on one side of the resin layer 2 while being exposed. The fillers 1A and 1B are not in contact with each other in a plan view of the film, and the fillers 1A and 1B are regularly dispersed without overlapping each other in the film thickness direction, and the positions of the fillers 1A and 1B in the film thickness direction are aligned. It constitutes a single-layer filler layer.

The surfaces 2a and 2b of the resin layer 2 around the individual fillers 1A and 1B are formed with an inclination 2x with respect to the tangential plane 2p of the resin layer 2 in the central portion between adjacent fillers. As will be described later, in the filler-containing film of the present invention, undulations 2y may be formed on the surface of the resin layer immediately above the fillers 1A and 1B embedded in the resin layer 2 (Fig. 4).

In the present invention, the term “inclination” means that the flatness of the surface of the resin layer is impaired near the fillers 1A and 1B, and the amount of resin is reduced due to lack of part of the resin layer with respect to the tangential plane 2p. means state. In other words, with the inclination, the surface of the resin layer around the filler is lacking with respect to the tangential plane. On the other hand, "undulation" means that the surface of the resin layer directly above the filler has undulations, and the resin is reduced due to the presence of portions with height differences such as undulations. In other words, the amount of resin in the resin layer directly above the filler is smaller than when the surface of the resin layer directly above the filler is on the tangential plane. These can be recognized by contrasting the portion corresponding to directly above the filler and the flat surface portion between the fillers (FIGS. 1B and 4). Note that the undulation starting point may exist as an inclination.

As described above, the inclination 2x (FIG. 1B) is formed around the fillers 1A and 1B exposed from the resin layer 2, so that when the filler-containing film is configured as an anisotropic conductive film, the anisotropic The resistance received from the resin against the flattening of the fillers 1A and 1B that occurs when the fillers 1A and 1B are sandwiched between the terminals at the time of conductive connection is reduced compared to the case where there is no inclination 2x. Since it becomes easier to hold the wire, the conduction performance is improved, and the trapping property is improved. This slope preferably follows the contour of the filler. This is because, in addition to the effect of connection becoming more likely to be exhibited, the filler can be easily recognized, thereby facilitating inspection in the production of a filler-containing film such as an anisotropic conductive film. Also, the inclination and undulations may partially disappear when the resin layer is heat-pressed, but the present invention includes this. In this case, the filler may be exposed at one point on the surface of the resin layer. When the filler-containing film is configured as an anisotropic conductive film, there are various electronic components to be connected, and as long as tuning is performed according to these, it is desired that the degree of freedom in design is high so as to satisfy various requirements. Therefore, the slope or undulation can be reduced or partially eliminated.

In addition, since undulations 2y (FIG. 4) are formed on the surface of the resin layer 2 directly above the fillers 1A and 1B that are buried without being exposed from the resin layer 2, the filler-containing film is configured as an anisotropic conductive film, a pressing force from the terminal is likely to be applied to the filler during anisotropic connection. Also, due to the undulations, the amount of resin directly above the filler is less than when the resin is deposited flatly, so the resin directly above the filler is more likely to be expelled during connection, and the terminal and filler are separated. Since it becomes easy to contact, the capping property of the filler in the terminal is improved, and the conduction reliability is improved.

In order to make it easier to obtain the effects of the inclination 2x (FIG. 1B) of the resin layer 2 around the exposed portions of the fillers and the undulations 2y (FIG. 4) of the resin layer directly above the fillers, the exposed portions of the fillers 1A and 1B are The ratios (Le/DA) and (Le/DB) of the maximum depth Le of the peripheral slope 2x and the particle diameters DA and DB of the fillers 1A and 1B are preferably less than 50%, more preferably less than 30%, and further It is preferably 20 to 25%, and the ratio of the maximum diameter Ld of the slope 2x around the exposed portion of the fillers 1A and 1B to the particle diameters DA and DB of the fillers 1A and 1B (Ld/DA), (Ld/DB) is preferably 100% or more, more preferably 100 to 150%, and the ratio (Lf /DA) and (Lf/DB) are greater than 0, preferably less than 10%, more preferably 5% or less.

The diameter Lc of the exposed portions of the fillers 1A and 1B can be less than the particle diameters DA and DB of the fillers 1A and 1B, preferably 10 to 90% of the particle diameters DA and DB. Alternatively, the conductive particles 1 may be exposed at one point at the top, or DA and DB may be completely buried in the resin layer 2 so that the diameter Lc becomes zero.

In the present invention, the presence of the inclination 2x and the undulations 2y on the surface of the resin layer 2 can be confirmed by observing a cross section of a filler-containing film such as an anisotropic conductive film with a scanning electron microscope. It can also be confirmed by in-plane visual field observation. Observation of inclination 2x and undulation 2y is also possible with an optical microscope and a metallurgical microscope. Also, the magnitude of the inclination 2x and the undulation 2y can be confirmed by adjusting the focus during image observation. The same is true even after reducing the slope or undulation by heat pressing as described above. This is because traces may remain.

(Thickness of resin layer)
In the filler-containing film such as the anisotropic conductive film of the present invention, the ratios (La/DA) and (La/DB) of the layer thickness La of the resin layer 2 and the average particle diameters DA and DB of all the fillers 1A and 1B are , preferably 0.3 or more, 0.6 to 10, more preferably 0.6 to 8, still more preferably 0.6 to 6. As the average particle diameters DA and DB, when the average particle diameters of the filler 1A in the first filler layer and the filler 1B in the second filler layer are different, their averages may be used. If the layer thickness La of the resin layer 2 is too large and the ratio exceeds 10, when the filler-containing film is configured as an anisotropic conductive film, the fillers 1A and 1B, which are conductive particles, are misaligned during anisotropic conductive connection. and the ability to capture the fillers 1A and 1B at the terminals is reduced. Conversely, if the layer thickness La of the resin layer 2 is too small and this ratio is less than 0.6, it becomes difficult to maintain the fillers 1A and 1B in the predetermined arrangement in the resin layer 2 .

(Composition of resin layer)
The resin layer 2 may be conductive or insulating, or may be plastic or curable, depending on the intended use of the filler-containing film. Preferably, it is made of an insulating curable resin composition. For example, it can be formed from an insulating thermally polymerizable composition containing a thermally polymerizable compound and a thermal polymerization initiator. The thermally polymerizable composition may contain a photopolymerization initiator, if necessary. Known resins and compounds can be used for these. An anisotropic conductive film in one aspect of the filler-containing film will be mainly described below, and the case of an insulating resin will be described.

When a thermal polymerization initiator and a photopolymerization initiator are used together, a thermally polymerizable compound that also functions as a photopolymerizable compound may be used, and a photopolymerizable compound is contained separately from the thermally polymerizable compound. may Preferably, a photopolymerizable compound is contained separately from the thermally polymerizable compound. For example, a cationic curing initiator is used as the thermal polymerization initiator, an epoxy resin is used as the thermally polymerizable compound, a photoradical initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound.

A plurality of photopolymerization initiators that react to light with different wavelengths may be contained. As a result, when the filler-containing film is configured as an anisotropic conductive film, photocuring of the resin constituting the insulating resin layer during the production of the anisotropic conductive film and adhesion of electronic components during anisotropic connection It is possible to use different wavelengths for photocuring of the resin for curing.

In the photo-curing during the production of the anisotropic conductive film in one embodiment of the filler-containing film, all or part of the photopolymerizable compound contained in the resin layer can be photo-cured. This photocuring maintains or fixes the arrangement of the fillers 1A and 1B in the resin layer 2, and is expected to suppress short circuits and improve trapping. Moreover, the viscosity of the resin layer in the manufacturing process of the anisotropic conductive film may be appropriately adjusted by this photocuring.

The blending amount of the photopolymerizable compound in the resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. This is because if the amount of the photopolymerizable compound is too large, the pushing force applied during connection increases. Especially in the case of anisotropic connection, this is preferable. This is to achieve both resin flow and pushing of the conductive particles held by the resin.

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

Here, as the (meth)acrylate compound, a conventionally known thermally polymerizable (meth)acrylate monomer can be used. For example, monofunctional (meth)acrylate monomers and bifunctional or higher polyfunctional (meth)acrylate monomers can be used.

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

If the amount of the thermal radical polymerization initiator used is too small, curing will be poor, and if it is too large, the product life will be shortened. 5 to 40 parts by mass.

Examples of epoxy compounds include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, novolac-type epoxy resins, modified epoxy resins thereof, and alicyclic epoxy resins, and two or more of these can be used in combination. can. Moreover, in addition to the epoxy compound, an oxetane compound may be used in combination.

As the thermal cationic polymerization initiator, those known as thermal cationic polymerization initiators for epoxy compounds can be employed. For example, iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc. that generate acid by heat can be used. and in particular aromatic sulfonium salts, which exhibit good latency with respect to temperature, can be preferably used.

If the amount of the thermal cationic polymerization initiator used is too small, it tends to cause poor curing, and if it is too large, the product life tends to be shortened. parts, more preferably 5 to 40 parts by mass.

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

The thermally polymerizable composition may contain an insulating filler in addition to the fillers 1A and 1B to adjust the melt viscosity. Examples include silica powder and alumina powder. The insulating filler preferably has a fine filler with a particle size of 20 to 1000 nm, and the blending amount may be 5 to 50 parts by mass with respect to 100 parts by mass of a thermally polymerizable compound (photopolymerizable composition) such as an epoxy compound. preferable. The insulating filler to be contained separately from the fillers 1A and 1B is preferably used when the application of the filler-containing film is an anisotropic conductive film. A filler may be contained. When the filler-containing film is configured as an anisotropic conductive film, the resin layer forming the filler-dispersed layer may contain finer insulating fillers (so-called nano-fillers) different from the fillers 1A and 1B, if necessary. can be included.

The filler-containing film of the present invention contains fillers, softeners, accelerators, antioxidants, colorants (pigments, dyes), organic solvents, ion catchers, etc., in addition to the insulating or conductive fillers described above. may be included.

<Deformation mode of filler-containing film>
(filler unit)
The filler-containing film of the present invention can take various forms regarding the arrangement of the filler.

For example, as in a filler _- containing film 10C such as an anisotropic conductive film shown in FIGS. Filler unit 1C ₂ is formed with filler 1B, filler units 1C ₁ and 1C ₂ do not contact each other, do not overlap even when the filler-containing film is viewed from above, and filler units 1C ₁ and 1C ₂ are arranged in a lattice. I can give you something. In this case, the number of fillers 1A per filler unit 1C ₁ of the first filler layer can be, for example, 2 to 9, particularly 2 to 4. In the filler unit, the fillers 1A may be arranged in a row or aggregated in a mass. Similarly, the number of fillers 1B per filler unit 1C ₂ of the second filler layer can be, for example, 2 to 9, particularly 2 to 4. The fillers 1B may be arranged in a line in the filler unit, or may be aggregated in a lump. In the case of an anisotropic conductive film, this can also be applied by arranging filler units so as to reduce the risk of short circuit according to the terminal layout. For applications other than the anisotropic conductive film, it may be appropriately adjusted according to the purpose.

In the case of an anisotropic conductive film, from the viewpoint of improving the catching property of the filler (conductive particles) and suppressing short circuit, preferably, the filler unit 1C ₁ of the first filler layer and the filler of the second filler layer Preferably, each unit _1C2 is composed of a single row of fillers with their longitudinal directions non-parallel, and particularly preferably perpendicular, as shown in FIGS. 7A and 7B.

Further, as in a filler-containing film 10D such as an anisotropic conductive film shown in FIGS. The filler unit 1C may be formed by contacting or adjoining a plurality of fillers 1B. It is preferable to regularly arrange the filler units 1C without contacting the filler units 1C with each other. The number of fillers 1A in the first filler layer per filler unit 1C is 2 to 9, particularly 2 to 4, and the number of fillers 1B in the second filler layer is 2 to 9, particularly 2 to 4. It is preferable to In the same way as described above, in the case of an anisotropic conductive film, it can also be applied by arranging filler units so as to reduce the risk of short circuit according to the terminal layout. For applications other than the anisotropic conductive film, it may be appropriately adjusted according to the purpose.

In the case of an anisotropic conductive film, a filler-containing film 10D having a filler unit 1C formed from a plurality of fillers (conductive particles) 1A and 1B is used for anisotropic conductive connection, and in the film thickness direction By pressing, as shown in FIG. 9, the fillers (conductive particles) 1A and 1B that are in contact with each other can be spread radially and the fillers (conductive particles) 1A and 1B can be separated from each other. In this case, as shown in FIG. 10, even in the inter-terminal region where the fillers (conductive particles) 1A, 1B are not pressed by the terminals 20, 21 facing each other, the fillers forming the filler unit 1C before the anisotropic conductive connection 1A and 1B are separated. Therefore, according to this filler-containing film 10D, short-circuiting between adjacent terminals can be suppressed. On the other hand, even when the conductive particles 1A and 1B are positioned at the edges of the terminals 20 and 21 facing each other before the anisotropic conductive connection, at least one of the fillers 1A and 1B is captured by the terminals 20 and 21 due to the anisotropic conductive connection. be done. Therefore, according to this filler-containing film 10D, the trapping efficiency of the conductive particles is improved. You may form such a filler unit 1C also for uses other than an anisotropic conductive film according to the objective. It is considered preferable to apply when pressing with pressure rollers. This is because the pressure load is likely to be applied in directions other than the thickness direction of the film.

(Embodiment in which the lack of arrangement of one filler layer is compensated for by the other filler layer)
One filler layer of the first filler layer and the second filler layer is formed in a predetermined arrangement and a predetermined number density in terms of design, and then the arrangement and number density of the fillers are confirmed for the entire region, and one of the conductive particles The other filler layer is formed so as to match the particle arrangement of the layer, and if necessary, to compensate for the lack of the particle arrangement of one filler layer, and the filler-containing film as a whole such as an anisotropic conductive film has a filler. may be arranged in a predetermined manner and omissions may be eliminated. Therefore, the filler layer formed later may have a different number density in the longitudinal direction of the filler-containing film. By doing so, the yield of the filler-containing film is improved, and an effect of cost reduction can be expected.

(Lamination of the second resin layer)
Like a filler-containing film 10E such as an anisotropic conductive film shown in FIG. 2 resin layers 4 may be laminated. In addition, when the embedding ratios of the first filler layer and the second filler layer in the resin layer 2 are different, and the first filler layer is exposed from the resin layer more than the second filler layer, the anisotropy shown in FIG. The second resin layer 4 may be laminated on the first resin layer side having a large amount of protrusion from the resin layer 2, such as a filler-containing film 10F such as an anisotropic conductive film shown in FIG. 11C. The second resin layer 4 may be laminated on the surface of the resin layer 2 where the filler layer does not protrude like the filler-containing film 10G. The lamination of the second resin layer 4 fills the spaces formed by the electrodes and bumps of the electronic parts when anisotropically conductively connecting the electronic parts using a filler-containing film such as an anisotropic conductive film, Adhesion can be improved. When laminating the second resin layer 4, the second resin layer 4 is attached to the electronic component to be pressed by the tool (the resin layer 2 is attached to the electronic component placed on the stage). to) is preferred. By doing so, it is possible to avoid unintentional movement of the filler, and to improve the trapping property.

The difference in the minimum melt viscosity between the resin layer 2 and the second resin layer 4 makes it easier for the space formed by the electrodes and bumps of the electronic component to be filled with the second resin 4, and the adhesiveness between the electronic components increases. can be expected to improve In addition, the larger the difference, the smaller the amount of movement of the resin 2 existing in the filler dispersed layer 3, so that the ability of the terminal to capture the filler is likely to be improved. Practically, the minimum melt viscosity ratio between the resin layer 2 and the second resin layer 4 is preferably 2 or more, more preferably 5 or more, and even more preferably 8 or more. On the other hand, if this ratio is too large, when a filler-containing film such as a long anisotropic conductive film is wound, there is a risk of resin extrusion or blocking. More specifically, the preferred minimum melt viscosity of the second resin layer 4 satisfies the above ratio and is 3000 Pa·s or less, more preferably 2000 Pa·s or less, and particularly 100 to 2000 Pa·s.

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

The layer thickness of the second resin layer 4 is preferably 4 to 20 μm. Alternatively, it is 1 to 8 times the filler diameter.

In addition, the minimum melt viscosity of the entire filler-containing films 10E, 10F, 10G such as anisotropic conductive films in which the resin layer 2 and the second resin layer 4 are combined is practically 8000 Pa s or less, preferably 200 to 7000 Pa. ·s or less, particularly preferably 200 to 4000 Pa·s.

(Lamination of the third resin layer)
A third resin layer may be provided on the opposite side of the second resin layer 4 and the resin layer 2 . The third resin layer can function as a tack layer.

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

(Other lamination modes)
Depending on the application of the filler-containing film, a plurality of filler-dispersed layers 3 may be laminated, and a layer containing no filler such as a second resin layer may be interposed between the laminated filler-dispersed layers. , the outermost layer may be provided with a second resin layer or a third resin layer.

<Method for producing filler-containing film>
The filler-containing film of the present invention having a single layer of the filler-dispersed layer 3 as the resin layer holds, for example, the filler 1A on one surface of the resin layer 2 in a predetermined distribution (preferably in a predetermined arrangement), The filler 1A is pressed into the resin layer 2 with a flat plate, a roller, or the like, and the filler 1B is similarly held in a predetermined distribution (preferably in a predetermined arrangement) and pressed into the other surface of the resin layer 2. can be done. In addition, when holding the filler in a predetermined dispersed state on both sides of the resin layer, it is possible to attach it by using a coating roll, attaching it using a transfer mold, and attaching it by various methods. It is preferable that the direction in which the filler is held on one surface of the resin layer and the direction in which the filler is held on the other surface are reversed (180 degrees). This makes it possible to alleviate the non-uniformity of the filler dispersion state on the front surface of the film and the non-uniformity of the filler dispersion state on the rear surface of the film when viewed together.

A filler-containing film such as an anisotropic conductive film in which the second resin layer 4 is laminated on the filler-dispersed layer 3 can be obtained, for example, as shown in FIG. That is, the filler 1A is attached to one surface of the resin layer 2 (a in the figure) and pushed in (b in the figure), and then the second resin layer 4 is laminated on the surface where the filler 1A is pushed in (the same figure). c). A filler 1B is attached to the surface of the resin layer 2 opposite to the second resin layer 4 (d), and the filler 1B is pushed into the resin layer 2 (e). Thus, a filler-containing film 10 such as an anisotropic conductive film in which the second resin layer 4 is laminated on the filler-dispersed layer 3 can be obtained. In this case, by appropriately setting the placement of the filler 1A that is pushed in from one surface of the resin layer 2 and the placement of the filler 1B that is pushed in from the other surface, these fillers 1A and 1B are in contact or close to each other in a plan view. Form 1C.

A filler-containing film such as an anisotropic conductive film in which the resin layer is formed from a single layer of the filler-dispersed layer 3 is also an anisotropic conductive film in which the second resin layer 4 is laminated on the filler-dispersed layer 3. For the filler-containing film and also for the mode in which the third resin layer is laminated, the method of attaching the fillers 1A and 1B to the resin layer 2 or the method of forming the resin layer 2 in which the fillers 1A and 1B are dispersed Examples include a method of transferring the filler to the resin layer using a transfer mold, a method of scattering the filler on the resin layer, and a method of coating with regular grooves on the surface such as a gravure coater similar to the method described in Patent Document 1. A method of applying a resin liquid containing a filler to a resin layer or a release film using a machine roll can be mentioned. In the method of applying a resin solution containing a filler to the release film using a coating roll, the resin layer 2 can be formed by the method. In the method described in Patent Document 1, as described above, it is presumed that the filler cannot be arranged in a more precise regular arrangement than the method using a transfer mold. However, in the present invention, the first filler layer is formed. By reversing the adhesion direction in the longitudinal direction of the anisotropic conductive film between the filler 1A that forms the second filler layer and the filler 1B that forms the second filler layer, when forming the conductive particle layer, the missing fillers and uneven number density can occur. Even when is formed, there is almost no overlapping of filler omissions and portions with uneven number density in both the first filler layer and the second filler layer, so filler (conductive particles) omission in each filler layer It is possible to reduce the influence of non-uniformity of the number density and the number density on the conduction characteristics.

Among the above-described methods, it is preferable to use a transfer mold from the viewpoint of improving the accuracy of the arrangement of the filler. As the transfer mold, for example, openings are formed in inorganic materials such as silicon, various ceramics, glass, metals such as stainless steel, and organic materials such as various resins by a known opening forming method such as photolithography. things can be used. Further, the transfer mold can have a shape such as a plate shape or a roll shape.

In general, in the step of attaching filler such as conductive particles to a resin layer using a transfer mold, in order to produce a filler-containing film such as a long anisotropic conductive film, the direction from one end of the resin layer to the other end is However, as the filler attachment process continues, the filler does not adhere to the resin layer due to clogging of the mold, and the filler is removed from the filler-containing film such as an anisotropic conductive film. places tend to increase. Therefore, when the filler for the first filler layer is attached from one end to the other end of the resin layer, the filler for the second filler layer is preferably attached from the other end to the one end of the resin layer. By reversing the adhesion direction in this way, a region with a high presence probability of missing conductive particles in the first filler layer becomes a region with a low presence probability of missing filler in the second filler layer. It is possible to make the number density of the filler uniform throughout the filler-containing film, and to eliminate excessive omission (connection failure in the case of an anisotropic conductive film) that affects the performance of the filler in anisotropic conductive connection. can be done. In addition, a filler-containing film such as a long anisotropic conductive film is generally produced as a wound body. The resin layer is formed into a wound body by adhering the filler to be the first filler layer from one end to the other end of the resin layer, and then the wound body is unwound and the filler to be the second filler layer is added, It is preferable that the first filler layer is attached to the resin layer in a direction opposite to the attachment direction, and the resin layer is used as a wound body. This simplifies the process by unwinding the wound body of the resin layer on which the first filler layer is formed, and again attaching the filler to be the second filler layer to the resin layer in the same direction as the first filler layer. Therefore, the effect of cost reduction can be expected. When reversing the adhesion direction, the clogged transfer mold may be replaced with a new one or cleaned as necessary. In the case of a product that allows a certain amount of filler to come off, it is possible to reduce the frequency of replacement and cleaning of the transfer mold, which is also expected to reduce costs.

Also in the method of applying a resin solution containing conductive particles to a resin layer or release film using a coating roll, the grooves on the surface of the coating roll become clogged with the continuation of coating, and the filler flows from the other end of the film. It is preferred to apply towards one end.

In addition, even in the method of dispersing the filler in the resin layer, the filler may be removed periodically. Even in such a case, when the filler that forms the first filler layer is adhered to the resin layer, and when the filler that forms the second filler layer is adhered to the resin layer, the traveling direction of the resin layer can be reversed. This is preferable from the viewpoint that the locations where voids are generated do not overlap on the front and back of the resin layer.

When producing a filler-containing film such as a long anisotropic conductive film by any of the above-described production methods, it is expected that a portion where the filler will come off will inevitably be formed. , By reversing the attachment direction of the filler in the longitudinal direction of the filler-containing film such as an anisotropic conductive film of the first filler layer and the second filler layer, it becomes void on the filler-containing film such as an anisotropic conductive film It is possible to disperse the missing parts without concentrating the parts in one place. Therefore, it is possible to contribute to improvement in the yield of filler-containing films such as anisotropic conductive films and reduction in manufacturing costs.

In addition, reversing the attachment direction of the first filler layer and the attachment direction of the second filler layer in the filler-containing film such as an anisotropic conductive film is effective for the arrangement pattern and number density of the fillers in the first filler layer, and the second filler layer. It is effective in reducing variations in filler number density in a filler-containing film such as an anisotropic conductive film, regardless of whether the two fillers have the same arrangement pattern or number density. For example, when designing a filler-containing film such as an anisotropic conductive film, the arrangement of the fillers in the first filler layer and the second filler layer is the same, and the number density of each is set to, for example, 400/mm ² , The absolute value of the difference in the number density between one end and the other end in the longitudinal direction of the filler-containing film such as an anisotropic conductive film that is actually manufactured according to the above-described manufacturing method is preferably 160/mm ² or less, more preferably 80 pieces / mm ² or less, and similarly when the number density of the conductive particles in the first filler layer and the second filler layer is set to 65000 pieces / mm ² respectively, one end and the other end in the longitudinal direction of the anisotropic conductive film The absolute value of the difference in number density is preferably 26,000/mm ² or less, more preferably 13,000/mm ² or less. That is, the absolute value of the difference in the number density between one end and the other end of the filler-containing film such as an anisotropic conductive film is the average number density of the conductive particles in the first filler layer and the second filler layer combined. 800 to 130000/mm ² , preferably within the range of ±20%, more preferably within the range of ±10%. The present invention does not exclude cases where the number density is less than 400/mm ² . Moreover, although an anisotropic conductive film is described as an example, it is not limited to this. For example, it can be easily inferred that making the number density uniform can stabilize the performance of an optical film as well. The same can be said for materials that are directly related to the appearance, such as matte films.

The embedding amount of the fillers 1A and 1B adhered to the resin layer 2 can be adjusted by the pressing force, temperature, etc., when the fillers 1A and 1B are pressed. can be adjusted by the viscosity of the resin layer 2 during pressing, the pressing speed, the temperature, and the like. As a pressing method for achieving a filling rate of more than 100%, there is a method of pressing with a pressing plate having protrusions corresponding to the arrangement of the filler.

A filler-containing film such as an anisotropic conductive film that is formed in a long length is cut as appropriate to obtain a product of a filler-containing film such as an anisotropic conductive film as a wound body. Therefore, the filler-containing film such as the anisotropic conductive film of the present invention has a length of, for example, 5 to 5000 m and can be made into a wound body.

In order to economically connect electronic parts using the anisotropic conductive film included in the filler-containing film, the anisotropic conductive film is preferably long to some extent. Therefore, the anisotropic conductive film is manufactured to have a length of preferably 5 m or longer, more preferably 10 m or longer, and even more preferably 25 m or longer. On the other hand, if the anisotropic conductive film is excessively long, it becomes impossible to use the conventional connecting device used when manufacturing electronic parts using the anisotropic conductive film, and the handleability is also inferior. Therefore, the anisotropic conductive film is preferably manufactured to have a length of 5000 m or less, more preferably 1000 m or less, and even more preferably 500 m or less. Such a long anisotropic conductive film is preferably wound around a winding core from the viewpoint of excellent handleability.

<How to use the filler-containing film>
The filler-containing film of the present invention can be used in the same manner as conventional filler-containing films, and there are no particular restrictions on the article as long as the filler-containing film can be laminated together. The filler-containing film can be attached to various articles by pressure bonding, preferably by thermocompression bonding, depending on the application. At the time of bonding, light irradiation may be used, or heat and light may be used in combination. For example, when the resin layer of the filler-containing film has sufficient adhesiveness to the article to which the filler-containing film is attached, the filler-containing film is formed into one article by lightly pressing the resin layer of the filler-containing film against the article. A film stuck body stuck on the surface can be obtained. In this case, the surface of the article is not limited to a flat surface, and may be uneven or curved as a whole. When the article is in the form of a film or a flat plate, a pressure roller may be used to bond the filler-containing film to the article. Thereby, the filler of the filler-containing film and the article can also be directly bonded.

Alternatively, a filler-containing film may be interposed between two opposing articles, and the two opposing articles may be joined with a thermocompression roller or a compression tool so that the filler is sandwiched between the articles. Alternatively, the filler-containing film may be sandwiched between the articles so that the filler and the articles do not come into direct contact with each other.

In particular, when the filler-containing film is an anisotropic conductive film, a first electronic component such as an IC chip, an IC module, or an FPC, an FPC, and a glass substrate are bonded via the anisotropic conductive film using a thermocompression tool. , a plastic substrate, a rigid substrate, a ceramic substrate, or the like, for anisotropic conductive connection. IC chips or wafers may be stacked using an anisotropic conductive film to form multiple layers. In addition, the electronic components to be connected by the anisotropic conductive film of the present invention are not limited to the electronic components described above. It can be used for various electronic parts that have been diversifying in recent years.

Therefore, the present invention includes a connected structure in which the filler-containing film of the present invention is adhered to various articles by pressure bonding, and a method for producing the same. In particular, when the filler-containing film is an anisotropic conductive film, a method for manufacturing a connected structure for anisotropically conductively connecting electronic components using the anisotropic conductive film, and the connection obtained thereby Structures, that is, connection structures in which electronic components are anisotropically conductively connected to each other by the anisotropic conductive film of the present invention are also included.

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

Further, when the anisotropic conductive film is formed from a laminate of the conductive particle dispersed layer 3 and the second insulating resin layer 4, the conductive particle dispersed layer 3 is temporarily attached to the second electronic component such as various substrates. Then, the first electronic component such as an IC chip is aligned and placed on the second insulating resin layer 4 side of the temporarily press-bonded anisotropic conductive film, and is thermally press-bonded. The second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component. Also, the conductive particle dispersed layer 3 side can be temporarily attached to the first electronic component for use.

The anisotropic conductive film, which is one aspect of the filler-containing film of the present invention, will be specifically described below with reference to examples.
(1) Production of anisotropically conductive film
(1-1) Examples 1A and 1B to Example 8
With the formulation shown in Table 1, (i) a high-viscosity first insulating resin layer forming a conductive particle dispersed layer (hereinafter also referred to as A layer), (ii) lower than the first insulating resin layer A resin composition was prepared for forming a viscous second insulating resin layer (hereinafter also referred to as N layer) and (iii) a third insulating resin layer for forming a tack layer.

A resin composition that forms the first insulating resin layer (layer A) is applied with a bar coater onto a PET film having a film thickness of 50 μm, dried in an oven at 80° C. for 5 minutes, and coated on the PET film. An insulating resin layer having a thickness shown in is formed. Similarly, a second insulating resin layer (N layer) and a third insulating resin layer (tack layer) were formed on the PET film with the thicknesses shown in Table 2, respectively.

On the other hand, the conductive particles (average particle diameter 3 μm) of the first conductive particle layer have a square hole lattice arrangement shown in FIG. ² (Examples 1A and 1B) or 10000, 20000 or 30000 pieces/mm ² for COG (Examples 2 to 8). That is, a mold was prepared in which the projection pattern of the mold was in a square lattice arrangement and the angle θ between the lattice axis and the lateral direction of the anisotropic conductive film was 15°, and pellets of a known transparent resin were produced. The melted resin was poured into the mold and cooled to solidify, thereby forming a roll-shaped resin mold having recesses arranged in the pattern shown in FIG. 1A.

This resin mold recess is filled with conductive particles (Sekisui Chemical Co., Ltd., AUL703, average particle size 3 μm), the above-mentioned first insulating resin layer (A layer) is covered thereon, and a pressure roll is applied. The conductive particles were adhered over a length of 300 m from one end to the other end of the first insulating resin layer by pressing at 60° C. and 0.5 MPa. Then, the first insulating resin layer (A layer) is peeled from the mold, and the conductive particles on the first insulating resin layer (A layer) are pressed with a pressure roll (pressing conditions: 70 ° C., 0.5 MPa). was pressed into the first insulating resin layer (A layer) to form a first conductive particle layer. The indentation rate was 100%, and the conductive particles and the surface of the first insulating resin layer (A layer) were flush with each other. Around the pushed-in conductive particles, recesses were formed with respect to the tangential plane of the first insulating resin layer in the central portion between the adjacent conductive particles.

Next, the second insulating resin layer (N layer) is attached to the surface of the first insulating resin layer (A layer) into which the conductive particles are pressed by heating and pressurizing (45 ° C., 0.5 MPa). Conductive particles were adhered to the opposite surface over a length of 300 m in the same manner as described above, and the conductive particles were pressed in to form a second conductive particle layer, thereby obtaining a conductive particle dispersed layer. In this case, the first conductive particles (first conductive particle layer) and the second conductive particles (second conductive particle layer) were shifted by 3 μm in the lateral direction of the film. The running direction of the first insulating resin layer to which the conductive particles are adhered was reversed from that in the case of forming the first conductive particle layer. Also, when forming the second conductive particle layer, the indentation rate was set to 100% so that the conductive particles and the surface of the first insulating resin layer (A layer) were flush with each other. Around the pushed-in conductive particles, recesses were formed with respect to the tangential plane of the first insulating resin layer in the central portion between the adjacent conductive particles.

In Examples 1A, 2, 3, 4, 6, 7, and 8, the conductive particle-dispersed layer obtained as described above was used as an anisotropic conductive film. In Example 1B, the running direction of the film when the conductive particles that will be the first conductive particle layer are attached to the first insulating resin layer, and the conductive particles that will be the second conductive particle layer are attached to the first insulating resin layer. The running direction of the film was made equal when adhering to.

In Example 5, the third insulating resin layer (tack layer) was heated and pressurized (45 ° C., 0.5 MPa ).

In a region of 300 m in length from one end to the other end of the anisotropic conductive film of each example, 10 rectangular regions with a side of 200 μm were set at different positions in the longitudinal direction as measurement regions for the number density of conductive particles. Then, in this measurement area, the first conductive particle layer and the second conductive particle layer are observed with a metallurgical microscope, the number density of the conductive particles in each conductive particle layer is obtained, and the number density of the conductive particles from the one end to the other end. was investigated. The results are shown in Tables 2 and 3.

(1-2) Comparative Examples 1 to 3
As in Example 1, the first insulating resin layer (A layer), the second insulating resin layer (N layer), and the third insulating resin layer (tack layer) having the resin composition shown in Table 1 formed.

However, in Comparative Example 1, the conductive particles were uniformly dispersed in the resin composition forming the first insulating resin layer (A layer), applied to a PET film, and dried to remove the conductive particles from the surface. A monodisperse conductive particle dispersed layer having a density of 40,000 particles/mm ² was formed.

In Comparative Example 2, the same procedure as in Example 2 was performed except that only the first conductive particle layer on the side of the second insulating resin layer (N layer) was formed as the conductive particle layer at a surface density of 40000 particles/mm ² . to produce an anisotropic conductive film.

In Comparative Example 3, as the conductive particle layer, only the second conductive particle layer on the opposite side of the second insulating resin layer (N layer) was formed at a surface density of 40000 particles/mm ² . An anisotropic conductive film was produced in the same manner.

The anisotropic conductive films of Comparative Examples 1 to 3 were also investigated for the variation tendency (increase or decrease tendency) of the number density of the conductive particles from one end to the other end. The results are shown in Tables 2 and 3.

(2) Evaluation The anisotropic conductive films of Examples and Comparative Examples prepared in (1) were cut with an area sufficient for connection, and (a) initial conduction resistance, (b) reliability After the test, the conduction resistance, (c) particle trapping property, (d) short rate, and (e) temporary pressure bonding property were measured or evaluated. The results are shown in Tables 2 and 3.

In this case, as samples to be evaluated, in Examples 1A and 1B (anisotropic conductive film for FOG), one end and the other end in the length direction of the anisotropic conductive film having a length of 300 m were used. 2 to 8 and Comparative Examples 1 to 3 (anisotropic conductive film for COG) used the middle portion (portion of 150 m from one end) of the anisotropic conductive film in the longitudinal direction.

(a) Initial conduction resistance
(a1) Evaluation of conductive properties of anisotropic conductive film for FOG (Examples 1A and 1B)
A sample of an anisotropic conductive film was sandwiched between an FPC for evaluating conduction characteristics and a glass substrate, and heated and pressed (200 ° C., 5 MPa, 5 sec) with a tool width of 1.5 mm to obtain each connection for evaluation, The conduction resistance of the obtained connection for evaluation was measured. It is desirable that the initial conduction resistance is practically 1Ω or less. Therefore, an initial conduction of 1 Ω or less was evaluated as OK, and a case of more than 1 Ω was evaluated as NG.

Here, the terminal patterns of the FPC for evaluation and the glass substrate correspond to each other, and the sizes are as follows. When the FPC for evaluation and the glass substrate were connected, the longitudinal direction of the anisotropic conductive film was aligned with the lateral direction of the terminals.

PFC for evaluating conduction characteristics
Terminal pitch 50μm
Terminal width: Terminal space = 1:1
Polyimide film thickness/copper foil thickness (PI/Cu) = 38/8, Sn plating

Glass substrate Electrode ITO coating
thickness 0.7mm

(a2) Evaluation of conductive properties of anisotropic conductive films for COG (Examples 2 to 8, Comparative Examples 1 to 3)
A sample of an anisotropic conductive film was sandwiched between an IC for evaluating conduction characteristics and a glass substrate, and heated and pressed (180 ° C., 80 MPa, 5 seconds) to obtain each connection for evaluation. The conduction resistance of the connection was measured. It is desirable that the initial conduction resistance is practically 1Ω or less. Therefore, an initial conduction resistance of 1Ω or less was evaluated as OK, and a case of more than 1Ω was evaluated as NG.

Here, the terminal patterns of the evaluation IC and the glass substrate correspond to each other, and the sizes are as follows. When connecting the evaluation IC and the glass substrate, the longitudinal direction of the anisotropic conductive film was aligned with the lateral direction of the bumps.

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

Glass substrate Glass material Corning 1737F
Outline 30×50mm
thickness 0.5mm
Electrode ITO wiring

(b) Conduction resistance after reliability test The connection for evaluation prepared in (a) is placed in a constant temperature chamber at a temperature of 85 ° C and a humidity of 85% RH for 500 hours. It was measured. Practically, it is desirable that the conduction resistance after the reliability test is 6Ω or less. Therefore, 6Ω or less was evaluated as OK, and the case of over 6Ω was evaluated as NG.

(c) particle trapping
(c1) Evaluation of particle trapping property of anisotropic conductive film for FOG (Examples 1A and 1B)
The number of trapped conductive particles was measured for 100 FPC terminals in the area of 25×400 μm in the connection for conducting property evaluation, and the minimum number of trapped conductive particles was obtained, and evaluated according to the following criteria.
A (good): 3 or more B (practically no problem): less than 3

(c2) Evaluation of particle trapping properties of anisotropic conductive films for COG (Examples 2 to 8, Comparative Examples 1 to 3)
Using an IC for evaluation of particle trapping property, this IC for evaluation and a glass substrate corresponding to a terminal pattern are shifted by 6 μm in alignment and heated and pressurized (180 ° C., 80 MPa, 5 seconds), and the IC for evaluation. The number of trapped conductive particles was measured for 100 particles in a region of 6 μm×66.6 μm where the bump and the terminal of the substrate overlapped, and the minimum number of trapped particles was obtained and evaluated according to the following criteria. Practically, it is preferable that it is B evaluation or more.

IC for particle trapping evaluation
Outline 1.6×29.8mm
thickness 0.3mm
Bump specification size 12×66.6 μm, bump pitch 22 μm, bump height 12 μm

Particle trapping evaluation criteria A (good): 5 or more B (practically no problem): 3 or more and less than 5 C (poor): less than 3

(d) Short rate
(d1) Evaluation of short rate of anisotropic conductive film for FOG (Examples 1A and 1B)
The same FPC as the FPC for evaluating conduction characteristics was heated and pressed (200 ° C., 5 MPa, 5 sec) to non-alkali glass (thickness 0.7 mm), and the number of short circuits in the obtained connections for evaluation was measured. The rate of occurrence of short circuits was obtained from the number of short circuits and the number of gaps in the connection for evaluation, and evaluated according to the following criteria.
A (good): less than 50 ppm
B (practically no problem): 50 ppm or more and less than 200 ppm C (defective): 200 ppm or more

(d2) Evaluation of short rate of anisotropic conductive film for COG (Examples 2 to 8, Comparative Examples 1 to 3)
Using an IC for evaluating the short circuit rate, (a) obtaining an evaluation connection in the same manner as in the evaluation of the initial conduction resistance, measuring the number of short circuits in the obtained evaluation connection, and evaluating the measured number of short circuits The rate of occurrence of short-circuit was obtained from the number of gaps in the connecting members, and evaluated according to the following criteria.

Short-circuit rate evaluation IC (7.5 μm space comb tooth TEG (test element group))
Outline 15×13mm
thickness 0.5mm
Bump specifications Size 25×140 μm, distance between bumps 7.5 μm, bump height 15 μm

Short rate evaluation criteria A: less than 50 ppm B: 50 ppm or more and less than 200 ppm C: 200 ppm or more

(e) Temporary crimping property Using a crimping tool, an anisotropic conductive film with a PET film (width 1.5 mm, length 50 mm) is applied to ITO glass at a temperature of 60 ° C. or 70 ° C., a crimping pressure of 1 MPa, and a crimping time of 1 second. Temporary crimping was performed by pressing with In this case, a silicon rubber having a thickness of 350 μm was interposed as a cushioning material between the crimping tool and the PET film. The PET film was peeled off from 100 temporarily pressure-bonded samples in which the anisotropic conductive film was thus pressed against the ITO glass. At that time, the success or failure of the temporary press-bonding was conveniently judged as OK when not a single anisotropic conductive film was peeled off from the ITO glass together with the PET film, and NG when even one film was peeled off.
A: OK at 60°C or higher
B: OK at 70°C or higher
C: NG at 70°C or higher

As shown in Table 2, conductive particles are embedded in the front and back surfaces of the insulating resin layer at an embedding rate of 100%, respectively, and the conductive particles extend from one end to the other end in the length direction of the anisotropic conductive film. In Example 1A, in which the tendency of increase and decrease in the number density is opposite in the first conductive particle layer and the second conductive particle layer, the reliability of the conduction resistance and the conduction resistance at one end and the other end of the anisotropic conductive film , particle trapping rate, short-circuit rate, and temporary pressure-bonding properties were all evaluated as good. On the other hand, in Example 1B, in which the number density tends to increase and decrease in the first conductive particle layer and the second conductive particle layer, the total number of conductive particles in the first conductive particle layer and the second conductive particle layer At one end of the film where the density was low, there was a portion with poor particle trapping performance, and at the other end of the film where the number density was high, good evaluations including particle trapping performance were obtained. In this evaluation, since the connection area is sufficient, it is judged that there is no practical problem even if the evaluation is B for less than three.

As shown in Table 3, the anisotropic conductive films of Examples 2 to 8 also had conductive particles embedded in the front and back surfaces of the insulating resin layer at an embedding rate of 100%. The increasing and decreasing tendency of the number density of the conductive particles in the longitudinal direction was in the opposite direction between the first conductive particle layer and the second conductive particle layer, and all evaluation items were good. In particular, from Example 2 and Example 5, it was found that the anisotropic conductive film of the present invention has good temporary attachment property even without providing a tack layer, has excellent workability, and also has excellent particle trapping property. Recognize.

Further, from Comparative Example 1, it can be seen that when the conductive particles are monodispersed in the conductive particle dispersion layer, both the particle trapping property and the short-circuit rate are inferior. From Comparative Example 2, it can be seen that the particle trapping property is inferior when the conductive particle layer is formed only on the second insulating resin layer (N layer) side. It can be seen that the provisional pressure-bonding property is inferior when it is formed only on the side opposite to the flexible resin layer (N layer). In Comparative Example 3, when the temporary pressure-bonding temperature was set to 75° C., no anisotropic conductive film was peeled from the ITO glass even with 500 temporary pressure-bonding samples. It is recognized that it can be used in practice depending on the situation.

(3) Transfer rate Regarding the anisotropic conductive film of Example 1, the transfer rate of the conductive particles when forming the first conductive particle layer (first time) and the transfer rate of the conductive particles when forming the second conductive particle layer (second time) Each transfer rate was measured.
Here, the transfer rate is the ratio of the number of conductive particles transferred to the first insulating resin layer to the number of conductive particles filled in the resin mold.

The transfer rate is measured by measuring the number of conductive particles in the first conductive particle layer or the second conductive particle layer existing in an area of 1 mm ² at lengths of 0 m, 50 m, 100 m, 200 m, and 300 m of the anisotropic conductive film. was measured using and the average was calculated. The first conductive particle layer (first time) transfers the conductive particles in the direction from the 0 m side to the 300 m side of the anisotropic conductive film, and the second conductive particle layer (second time) is the anisotropic conductive film. It was formed by transferring from the 300 m side to the 0 m side.

As a result, in both the first conductive particle layer and the second conductive particle layer, the transfer rate exceeded 99.9% up to 100 m from the transfer start point, but the transfer rate decreased as the transfer progressed. However, the total transfer rate of the first conductive particle layer and the second conductive particle layer exceeded 99.9% at any point up to 300 m from the transfer start point.

1A, 1B filler 1C, 1C _1, 1C ₂ filler unit 2 resin layer 2a, 2b surface of resin layer 2x recess 2y recess 3 filler dispersion layer 4 second resin layer 10, 10A, 10B, 10C, 10D, 10E, 10F , 10G Filler-containing film of Example 10Ap One end of filler-containing film 10Aq Other end of filler-containing film 20, 21 Terminal 30 First electronic component 31 Second electronic component A Lattice axis of filler arrangement DA, DB Particle diameter La Resin layer layer thickness L1, L2 embedded amount L3 distance between nearest particles between fillers in the first filler layer L4 distance between nearest particles between fillers in the second filler layer Lc diameter of exposed portion of filler Ld dent (inclination ) Maximum diameter Le Maximum depth of dent (tilt) Lf Maximum depth of dent (undulation) θ Angle between the longitudinal direction of the terminal and the lattice axis of the array of conductive particles

Claims (19)

A resin layer, a first filler layer composed of a filler dispersed in a single layer in the resin layer, and a second filler composed of a filler dispersed in a single layer in the resin layer at a depth different from that of the first filler layer. A filler-containing film comprising a filler-dispersed layer having a layer,
The filler of the first filler layer is exposed from one surface of the resin layer or is close to the one surface,
The filler of the second filler layer is exposed from the other surface of the resin layer or is close to the other surface,
A filler unit composed of a plurality of fillers is formed in the filler dispersion layer,
The surface of the resin layer in the vicinity of the filler has an inclination or undulations with respect to the tangential plane of the resin layer in the central portion between the adjacent fillers, and in the inclination, the surface of the resin layer around the filler is oriented with respect to the tangential plane. A filler-containing film in which the amount of resin in the resin layer directly above the filler is smaller in the undulations than when the surface of the resin layer directly above the filler is on the tangential plane. 2. The filler-containing film according to claim 1, wherein the ratio (La/D) of the layer thickness (La) of the resin layer to the average particle diameter D of the filler is 0.6-10. 3. The filler-containing film according to claim 1, wherein a plurality of fillers are arranged in a line or aggregated in the filler unit. When the filler in the first filler layer is close to one surface of the resin layer and the filler in the second filler layer is close to the other surface of the resin layer, the filler in the first filler layer is close to the resin layer. The ratio (L1/DA) between the distance (L1) from one surface of the layer to the deepest part of the filler in the first filler layer and the particle diameter (DA) of the filler in the first filler layer is 110% or less. The filler of the second filler layer is embedded in the resin layer so that the distance (L2) from the other surface of the resin layer to the deepest part of the filler of the second filler layer and the distance (L2) of the second filler layer The filler-containing film according to any one of claims 1 to 3, wherein the filler-containing film is embedded in the resin layer so that the ratio (L2/DB) to the particle diameter (DB) of the filler is 110% or less. Filler units are formed in which the fillers in the first filler layer or the fillers in the second filler layer are in contact or close to each other, and the filler units are not in contact with each other and the filler units are regularly arranged. The filler-containing film according to any one of 1 to 4. 1. Filler units are formed in which the filler in the first filler layer and the filler in the second filler layer are in contact with or in close proximity to each other, and the filler units are not in contact with each other and the filler units are regularly arranged. 5. The filler-containing film according to any one of -4. 6. The filler-containing film according to claim 5, wherein the longitudinal direction of the filler units of the first filler layer and the longitudinal direction of the filler units of the second filler layer are non-parallel in plan view. The filler-dispersed layer and the second resin layer are laminated, and the second resin layer has a lower minimum melt viscosity than the resin layer forming the filler-dispersed layer. filler-containing film. The filler-containing film according to any one of claims 1 to 8, wherein the filler consists of two or more fillers. The filler-containing film according to any one of Claims 1 to 9, wherein the filler is at least one selected from inorganic fillers, organic fillers, fillers in which organic and inorganic materials are mixed, and conductive particles. The filler-containing film according to any one of claims 1 to 9, wherein the filler is conductive particles, the resin layer is an insulating resin layer, and the film is used as an anisotropic conductive film. A method for producing a filler-containing film according to any one of claims 1 to 10,
A filler is held on one surface of the resin layer in a predetermined dispersed state, the filler is pushed into the resin layer, another filler is held on the other surface of the resin layer in a predetermined divided state, and the filler is placed on the resin layer. A manufacturing method characterized by pressing into. 13. The manufacturing method according to claim 12, wherein conductive particles are used as the filler and an insulating resin layer is used as the resin layer in order to use the filler-containing film as an anisotropic conductive film. 14. The method according to claim 12 or 13, wherein when the filler is held on both surfaces of the resin layer in a predetermined dispersed state, the direction in which the filler is held on one surface of the resin layer and the direction in which the filler is held on the other surface are reversed. Production method. 11. A film-attached body in which the filler-containing film according to any one of claims 1 to 10 is attached to an article. A connected structure in which a first article and a second article are connected via the filler-containing film according to any one of claims 1 to 10. A connection structure in which a first electronic component and a second electronic component are anisotropically conductively connected via the filler-containing film according to claim 11 . A method for manufacturing a connected structure, wherein a first article and a second article are connected by crimping the first article and the second article through the filler-containing film according to any one of claims 1 to 10. A method for manufacturing a connected structure, wherein the first electronic component and the second electronic component are anisotropically conductively connected by thermocompression bonding the first electronic component and the second electronic component via the filler-containing film according to claim 11. .

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