JP7583265B2 - Manufacturing method of connector, connector - Google Patents

Description

The present invention relates to a method for manufacturing a connector using an anisotropic conductive film and to the connector.

Conventionally, the display panels of small electronic devices such as smartphones and tablet computers, and large image display devices such as large organic EL televisions, are composed of a display section and a wiring area arranged at least partially around the periphery of the display section. Terminals of various electronic components such as FPC (flexible printed circuit) boards are anisotropically conductively connected to the wiring area via an anisotropic conductive film. When making this anisotropic conductive connection, an anisotropic conductive film with a width equal to or less than the width of the wiring area is temporarily attached to the wiring area of the display panel, and the terminals of various electronic components such as the FPC board are aligned to the temporarily attached anisotropic conductive film, after which the anisotropic conductive connection process is performed (Patent Document 1).

In recent years, there has been a demand for narrower frames in the display panels of small electronic devices and large image display devices as described above. For this reason, attempts have been made to narrow the width of the mounting area around the periphery of the panel more than ever before, and inevitably, attempts have been made to further narrow the width of the wiring area within the mounting area (for example, to a width of 0.6 mm or less). Accordingly, attempts have been made to use anisotropic conductive films that are slit to a width equivalent to or less than the width of the mounting area of the display panel as a temporary attachment to such mounting areas.

JP 2007-90461 A

However, when attempting to slit anisotropic conductive film to narrower widths (for example, widths of 0.6 mm or less), there is a problem that it is difficult for the slitting blade to penetrate the anisotropic conductive film, the cut surface tends to be irregular, and the difficulty of the slitting work increases significantly. In addition, when attempting to pull out anisotropic conductive film from a roll made from anisotropic conductive film that has been slit to such a narrow width, there is a problem that pulling out defects such as blocking are likely to occur. Thus, when attempting to make narrow anisotropic conductive film and its roll compatible with the narrow frame of a display panel, there is a problem that the difficulty of manufacturing them increases.

In addition, in a mounting device that temporarily attaches an anisotropic conductive film to a wiring area of a display panel, the anisotropic conductive film needs to be accurately positioned in a narrow wiring area. However, it is expected that with the placement accuracy of conventional mounting devices, it will become more difficult to accurately place a narrow anisotropic conductive film in a narrow wiring area than ever before. If it becomes so difficult, when a connection is manufactured by anisotropic conductive connection by first temporarily attaching a narrow anisotropic conductive film to a display panel with a narrow frame of a small electronic device, a problem may occur in which the evaluation result of any one of the specified evaluation items (conductive resistance, insulation resistance, conductive particle capture, adhesive strength) of the manufactured connection is reduced to a level that cannot be applied to practical use. If such a problem occurs, for example, there is a concern that a connection failure such as a short circuit or a decrease in the number of captured conductive particles may occur when an anisotropic conductive connection is made using an anisotropic conductive film.

The object of the present invention is to solve the problems in the conventional technology. Specifically, when manufacturing a connection by anisotropically conductively connecting the terminal portion of a first electronic component such as an FPC board to an even narrower wiring area within a very narrow (e.g., 0.6 mm or less) mounting area of a second electronic component such as a narrow-framed display panel via an anisotropic conductive film, the object is to free the user from the constraint of having to use an anisotropic conductive film with a width equal to or smaller than the mounting area. The object is also to enable temporary attachment of the anisotropic conductive film using a conventional mounting device, and to prevent the evaluation results of the manufactured connection from being reduced to a level that is not practically applicable for any of the specified evaluation items (conductive resistance, insulation resistance, conductive particle capture, adhesive strength).

The inventor hypothesized that "the problems with the prior art are due to the fact that the prior art is stuck to the common technical knowledge that an anisotropic conductive film must first be temporarily attached to the narrowed mounting area of a second electronic component such as a display panel in a small electronic device as the frame of the second electronic component such as a display panel becomes narrower, and that an anisotropic conductive film for this temporary attachment must be slit to a width equal to or smaller than the narrow width of the mounting area." Based on this hypothesis, the inventor discovered that the possibility of achieving the object of the present invention would increase if it were possible to use an anisotropic conductive film with a width equal to or larger than the width of the wiring area in the mounting area of a second electronic component such as a display panel. As a means of achieving this objective, the inventors discovered that, rather than first temporarily attaching the anisotropic conductive film to the narrowed mounting area of the second electronic component such as a display panel, it is possible to first temporarily attach the anisotropic conductive film to the terminal portion of the first electronic component such as an FPC board, and then adjust the relative positional relationship between the terminal portion of the first electronic component such as an FPC board, the wiring area within the mounting area of the second electronic component such as a display panel, and the anisotropic conductive film used to anisotropically conductively connect them to a predetermined relationship, thereby completing the present invention.

That is, the present invention provides a method for manufacturing a connection body in which a terminal portion of a first electronic component is anisotropically conductively connected to a wiring region within a mounting region of a second electronic component via an anisotropic conductive film, the method comprising the steps of:
a temporary attachment step of temporarily attaching an anisotropic conductive film to a first electronic component;
a placing step of placing the anisotropic conductive film temporarily attached to the first electronic component on a wiring region of the second electronic component;
a thermocompression bonding step of thermocompression bonding from the first electronic component side by a thermocompression bonding tool,
The present invention provides a method for manufacturing a connection body, in which an anisotropic conductive film has a first region sandwiched between opposing surfaces of a second electronic component and a first electronic component, and a second region adjacent to the first region, facing the first electronic component but not facing the second electronic component.

The present invention also provides a connection body in which a terminal portion of a first electronic component and a wiring region of a second electronic component are anisotropically conductively connected via an anisotropic conductive film having a conductive particle-containing layer in which conductive particles are contained in a binder resin layer,
The anisotropic conductive film provides a connection body characterized in that it has a first region sandwiched between the opposing surfaces of the second electronic component and the first electronic component, and a second region adjacent to the first region, facing the first electronic component but not facing the second electronic component.

In the method for manufacturing a connection body of the present invention, an anisotropic conductive film is temporarily attached to the terminal portion of a first electronic component such as an FPC board. This eliminates the need to make the width of the anisotropic conductive film used equal to or smaller than the width of the mounting area of a second electronic component such as a display panel. Therefore, an anisotropic conductive film whose width is greater than the width of the wiring area of the second electronic component and has stable anisotropic conductive properties can be used. Therefore, the anisotropic conductive film can be temporarily attached using a conventional mounting device, and temporary attachment with particularly high placement accuracy is not required. As a result, it is possible to avoid the evaluation results of the manufactured connection body being reduced to a level that cannot be applied to practical use for any of the specified evaluation items (conductive resistance, insulation resistance, conductive particle capture, adhesive strength).

FIG. 1 is an explanatory diagram of a temporary attachment step in the manufacturing method of the connection body of the present invention. FIG. 2 is an explanatory diagram of the placement step in the method for producing a connection body of the present invention. FIG. 3 is an explanatory diagram of the thermocompression bonding step in the method for producing a connection body of the present invention. FIG. 4 is a schematic cross-sectional view of a connector of the present invention. FIG. 5 is a schematic cross-sectional view of an anisotropic conductive film applied to the method for producing a connection body of the present invention.

The present invention is a method for manufacturing a connection body that anisotropically conductively connects a terminal portion of a first electronic component to a wiring area of a second electronic component via an anisotropic conductive film, and includes the following "temporary attachment step," "mounting step," and "thermocompression bonding step." Below, the method for manufacturing the connection body of the present invention will be described in detail for each step with reference to the drawings.

(Temporary attachment process)
In the temporary attachment step, as shown in Fig. 1, an anisotropic conductive film 20 is temporarily attached to a first electronic component 10. The position where the anisotropic conductive film 20 is temporarily attached to the first electronic component 10 is usually a position that covers a terminal portion 11 provided at the end of the first electronic component 10, and it is preferable that the first electronic component 10 and the anisotropic conductive film 20 are flush with each other at the end portion in order to facilitate alignment in the subsequent mounting step and to minimize the width of the anisotropic conductive film 20 itself. The temporary attachment operation itself can be performed in accordance with the temporary attachment operation of an anisotropic conductive film.

(First electronic component 10)
As the first electronic component 10, it is preferable to use an FPC board such as a known COF (chip on film) board. Note that hard glass boards and glass epoxy boards can also be used as long as they do not impair the effects of the present invention. In addition, as the terminal portion 11, it is possible to use a terminal material such as a metal such as Au, Ag, Cu, Ni, Ti, Al, Sn, Mo, or a metal alloy combining these metals, or a metal oxide such as ITO.

(Anisotropic Conductive Film 20)
The anisotropic conductive film 20 has a conductive particle-containing layer 23 having a structure in which conductive particles 22 are arranged two-dimensionally or three-dimensionally randomly or regularly (for example, in a lattice pattern such as a hexagonal lattice pattern or a square lattice pattern) in a binder resin layer 21. When the conductive particles are arranged randomly, the manufacturing operation of the anisotropic conductive film 20 can be simplified (for example, by kneading and dispersing the conductive particles in the binder resin and forming a film of the dispersion). When the conductive particles are arranged regularly, the amount of conductive particles used can be reduced, reducing the manufacturing cost of the anisotropic conductive film and also suppressing the occurrence of short circuits.

The binder resin layer 21 and the conductive particles 22 can be configured in the same manner as the binder resin layer and the conductive particles that constitute the conductive particle-containing layer of a known anisotropic conductive film. For example, the binder resin layer can be an acrylic resin composition layer or an epoxy resin composition layer. The layer thickness of the binder resin layer 21 is preferably 1 μm or more and 10 μm or less. In addition, the conductive particles can be metal or alloy particles such as nickel particles and solder particles, or metal-coated resin particles in which known resin particles are coated with a metal such as nickel. The average particle diameter of the conductive particles is preferably 1 μm or more and 10 μm or less. The surfaces of such conductive particles 22 may be insulated.

The number density of the conductive particles 22 in the binder resin layer 21 is preferably 1,000 to 500,000 particles/ ^mm2 . By setting the number density of the conductive particles 22 within this range, it is possible to provide the necessary number of captured conductive particles 22 for a connection terminal. This number density can be determined by observing the film in a plan view using an optical microscope.

The anisotropic conductive film 20 may be composed of only the conductive particle-containing layer 23, but it is preferable to use a structure in which an insulating resin layer 24 is further laminated, as shown in FIG. 5. Naturally, this insulating resin layer 24 is a layer that does not contain conductive particles. In this case, it is preferable that the conductive particle-containing layer 23 exhibits a higher melt viscosity than the insulating resin layer 24 in order to suppress unnecessary resin flow of the conductive particles during anisotropic conductive connection.

In the anisotropic conductive film 20, it is preferable that the conductive particles 22 are unevenly distributed on one side of the binder resin layer 21. If the conductive particles are unevenly distributed on one side, the conductive particles are more likely to come into contact with the wiring area of the second electronic component described later, and it is easier to improve the reliability of conduction during anisotropic conductive connection. As for the degree of uneven distribution, when the distance from the one side of the binder resin layer 21 of the anisotropic conductive film 20 to the conductive particles 22 is D and the layer thickness of the binder resin layer 21 is La, the ratio (%) of the distance D to the layer thickness La [(D/La) x 100] is preferably -5% or more and 40% or less, more preferably -5% or more and 15% or less, and particularly preferably -5% or more and 5% or less. If the ratio exceeds 40%, the conductive particles 22 are more likely to be displaced during anisotropic conductive connection, and the number of conductive particles captured between the terminal portion of the first electronic component and the wiring area of the second electronic component described later during anisotropic conductive connection decreases. Furthermore, if the ratio falls below -5% (if the conductive particles are exposed to a large extent from the binder resin layer), the insulating resin layer 24 will no longer be able to cover the conductive particles 22, and there is concern that the properties of the anisotropic conductive film 20, such as a decrease in adhesive ability, will be impaired. A particularly preferable degree of uneven distribution is that the conductive particles 22 are flush with the binder resin layer 21.

In addition, in this temporary attachment process, when the anisotropic conductive film is temporarily attached to the first electronic component, it is preferable to perform the temporary attachment from the side where the conductive particles are not unevenly distributed. This makes it easier to bring the conductive particles into contact with the wiring area of the second electronic component described below, making it easier to improve the conductivity reliability when making an anisotropic conductive connection.

In addition, when the anisotropic conductive film 20 has an insulating resin layer 24 as shown in FIG. 5, it is preferable to temporarily attach the anisotropic conductive film to the first electronic component in this temporary attachment process so that the insulating resin layer 24 side is located on the first electronic component 10 side. This is because the conductive particle-containing layer 23 is pressurized after the insulating resin layer 24 during anisotropic conductive connection, which suppresses unnecessary movement of the conductive particles 22 and prevents short circuits and a decrease in the number of captured particles.

(Placement process)
In the placing step, as shown in Fig. 2, after the temporary attachment step, the anisotropic conductive film 20 temporarily attached to the first electronic component 10 is placed on the wiring region 31 in the mounting region 30a of the second electronic component 30. When placing the anisotropic conductive film 20 in this placing step, alignment is performed so that a first region 20X is sandwiched between the opposing surfaces of the second electronic component 30 and the first electronic component 10, and a second region 20Y is adjacent to the first region 20X and faces the first electronic component 10 but does not face the second electronic component 30. When the anisotropic conductive film 20 is configured in this manner, even if the wiring region 31 of the second electronic component 30 is very narrow, the width of the anisotropic conductive film 20 can be made larger than the width of the wiring region 31. The alignment can be performed using a known alignment device or alignment mechanism. The first region 20X and the second region 20Y being "adjacent" means that the second region 20Y extends continuously and uninterrupted from the first region 20X.

(Second Electronic Component 30)
The second electronic component 30 may preferably be, for example, various image display panels such as a liquid crystal display panel using a glass substrate or an optical resin. The mounting area 30a is an area formed on at least a part of the periphery (frame) of the second electronic component 30, and is an area where anisotropic conductive connection with the first electronic component 10 is made. Inside the mounting area 30a, a wiring area 31 is formed from a terminal material such as a metal such as Au, Ag, Cu, Ni, Ti, Al, Sn, Mo, or a metal alloy combining these metals, or a metal oxide such as ITO.

(Thermocompression bonding process)
The thermocompression bonding process corresponds to the main curing process. As shown in FIG. 3, in this process, the first electronic component 10 is heated by a thermocompression bonding tool 40 in the direction of the arrow, and the first region 20X of the anisotropic conductive film 10 is thermocompressed to the wiring region 31 of the second electronic component 30. During this thermocompression bonding, a known buffer material (e.g., a Teflon (registered trademark) sheet having a thickness of 50 μm) may be interposed between the thermocompression bonding tool 40 and the first electronic component 10. At this time, the second region 20Y of the anisotropic conductive film 20 is not thermocompressed by the thermocompression bonding tool 40. Through this thermocompression bonding process, the connection body 100 of FIG. 4, which is a part of the present invention, is obtained. This connection body 100 has a structure in which the terminal portion 11 of the first electronic component 10 and the wiring region 31 of the second electronic component 30 are anisotropically conductively connected via the anisotropic conductive film 20 having a conductive particle-containing layer 23 in which conductive particles 22 are contained in the binder resin layer 21. This connection body 100 is configured such that the anisotropic conductive film 20 has a first region 20X that is sandwiched between the opposing surfaces of the second electronic component 30 and the first electronic component 10, and a second region 20Y that is adjacent to the first region 20X and faces the first electronic component 10 but not the second electronic component 30.

In this thermocompression bonding process, the relationship between the first electronic component 10, the second electronic component 30, and the anisotropic conductive film (ACF) 20 can be expressed by the following indices (widths) (a) to (f) shown in Figure 3.

(a) Mounting width:
This is the width of the frame of the second electronic component such as a display panel, and is not particularly limited, but is preferably 1 mm or less in response to the narrowing of the frames of the second electronic component such as a display panel, and cases of 0.2 mm or less are also envisioned.
(b) Wiring area width:
The width of the wiring area is the width of the wiring area provided within the mounting width, and the wiring area width is not larger than the mounting width. Since the mounting width is preferably 1 mm or less in response to narrower frames of second electronic components such as display panels, the width of the wiring area is preferably 0.1 mm or more.
(C) ACF first region width:
This is the width (overlap width) of the area that is sandwiched between the opposing surfaces of the first electronic component and the second electronic component and is thermocompression bonded by a thermocompression bonding tool. The first area width is equal to or smaller than the mounting width, but is preferably equal to or larger than 25% of the ACF width.
(D) Thermocompression tool position:
It is the distance from the inner edge of the mounting area (the edge of the display section), and if this value is negative, it indicates that the thermocompression bonding tool extends to the display section. It is 0% or more and less than 100% of the mounting area width, but preferably 5% or more and 70% or less.
(E) Thermocompression tool width:
The width of the thermocompression bonding tool is preferably 0.8 to 3 times the mounting width, in order to promote the curing reaction of the first region of the anisotropic conductive film while preventing the tool from contacting on one side. On the other hand, it is preferable that the width is larger than the width of the anisotropic conductive film, in order to promote the curing reaction of the anisotropic conductive film in the second region.
(F) ACF second region width:
The width of the region of the ACF facing the first electronic component but not facing the second electronic component, and is preferably equal to or less than the tool width. This is to increase the curing reaction rate of the ACF in the second region. In order to obtain sufficient connection strength, the second region is preferably equal to or less than 75% of the width of the anisotropic conductive film. Furthermore, it is required to increase the curing reaction rate of the film to a certain level, and in practical terms, it is preferably 60% or more, and more preferably 80% or more. The curing reaction rate can be calculated based on the peak intensities of the completely cured product and the uncured product in a general IR method, with the second region of the ACF that is not thermocompression-bonded of each evaluation connection body as the measurement site. In the second region of the ACF, which is the curing reaction rate measurement site, it is preferable to measure the vicinity of the center of gravity as a representative value.

The connection obtained in this way eliminates the need to use an anisotropic conductive film with a width equal to or smaller than the width of the mounting area when manufacturing a connection by anisotropically conductively connecting the terminal portion of a first electronic component such as an FPC board to an even narrower wiring area within a very narrow (e.g., 0.6 mm or less) mounting area of a second electronic component such as a narrow-framed display panel via an anisotropic conductive film, and also makes it possible to temporarily attach the anisotropic conductive film using a conventional mounting device (which does not require particularly high placement accuracy). As a result, the evaluation results for all of the specified evaluation items (conductive resistance, insulation resistance, conductive particle capture, adhesive strength) of the manufactured connection can be made to a level that is practically problem-free.

The present invention will now be described in more detail with reference to examples.

Examples 1 to 10, Comparative Examples 1 to 6
(1) Preparation of anisotropic conductive film (a) Preparation of binder resin layer A binder resin layer forming composition consisting of 40 parts by mass of phenoxy resin (YP-50, Nippon Steel Chemical & Material Co., Ltd.), 25 parts by mass of silica filler (Aerosil R805, Nippon Aerosil Co., Ltd.), 30 parts by mass of liquid epoxy resin (iER828, Mitsubishi Chemical Co., Ltd.), 2 parts by mass of silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.), and 3 parts by mass of thermal cationic polymerization initiator (SI-60L, Sanshin Chemical Industry Co., Ltd.) was applied onto a PET film having a film thickness of 50 μm with a bar coater, and dried in an oven at 80 ° C. for 5 minutes to form a binder resin layer having a thickness of 5 μm on the PET film. However, in Example 8, a binder resin layer having a thickness of 10 μm was formed on the PET film.

(b) Preparation of a Conductive Particle Transfer Mold A mold was prepared in which a convex pattern was formed so that the conductive particles were arranged in a square lattice arrangement in a plan view, and the number density of the conductive particles was 6,000 particles/mm ² for Example 10, 12,000 particles/mm 2 for Examples 1, 2, 4, and 6 to 8 and Comparative Examples 1 and 3 to 5, 16,000 particles/mm ² for Examples 3, 5, and 9 and Comparative Example ² , and 20,000 particles/mm ² for Comparative Example 6. A conductive particle transfer mold having a square lattice arrangement pattern was prepared by pouring pellets of a known transparent resin in a molten state into the mold and cooling and solidifying it.

(c) Preparation of a conductive particle-containing layer Metal-coated resin particles (Sekisui Chemical Co., Ltd., AUL703, average particle diameter 3 μm) were prepared as conductive particles, and these conductive particles were filled into the recesses of the conductive particle transfer mold, and the above-mentioned binder resin was placed on top of them and attached by thermocompression at 60° C. and 0.5 MPa. The binder resin layer was then peeled off from the conductive particle transfer mold, and the conductive particles on the binder resin layer were pressed into the binder resin layer by applying pressure (thermocompression bonding conditions: 60 to 70° C., 0.5 MPa) to prepare a conductive particle-containing layer. This conductive particle-containing layer was capable of functioning as a single-layer anisotropic conductive film. The embedding degree of the conductive particles (the ratio between the layer thickness La of the binder resin layer and the distance D from its surface to the conductive particles) was 0% in the cases of Examples 1 to 7 and Comparative Examples 1 to 5 (in other words, the conductive particles were unevenly distributed flush with one side of the binder resin layer), and 40% in the cases of Examples 8 to 10 and Comparative Example 6. The CV value of the metal-coated resin particles used was 20% or less when measured with an FPIA-3000 (Malvern Instruments) with 1000 or more particles.

(d) Formation of Insulating Resin Layer A composition for forming an insulating resin layer, consisting of 40 parts by mass of phenoxy resin (YP-50, Nippon Steel Chemical & Material Co., Ltd.), 5 parts by mass of silica filler (Aerosil R805, Nippon Aerosil Co., Ltd.), 50 parts by mass of liquid epoxy resin (iER828, Mitsubishi Chemical Co., Ltd.), 2 parts by mass of a silane coupling agent (KBM-403, Shin-Etsu Chemical Co., Ltd.), and 3 parts by mass of a thermal cationic polymerization initiator (SI-60L, Sanshin Chemical Industry Co., Ltd.), was applied onto a PET film having a film thickness of 50 μm with a bar coater, and dried in an oven at 80 ° C. for 5 minutes to form an insulating resin layer having a thickness of 5 μm on the PET film.

(e) Lamination of a conductive particle-containing layer and an insulating resin layer In Examples 1 to 7 and Comparative Examples 1 to 5, an insulating resin layer was laminated by a conventional method on the surface of the conductive particle-containing layer where the conductive particles were not unevenly distributed, thereby obtaining an anisotropic conductive film having a two-layer structure. In Examples 9 to 10 and Comparative Example 6, an insulating resin layer was laminated by a conventional method on the surface of the conductive particle-containing layer where the conductive particles were unevenly distributed, thereby obtaining an anisotropic conductive film having a two-layer structure. These anisotropic conductive films were applied to the manufacture of the following connection body. In Example 8, an insulating resin layer was not laminated, and a single binder resin layer was applied to the manufacture of a connection body.

(2) Manufacturing of a Connection Body (a) Preparation of Constituent Materials The following anisotropic conductive film, FPC board, and glass board were prepared for manufacturing a connection body.
*Anisotropic conductive film The anisotropic conductive film thus prepared was slit into a width of 0.6 mm using a slitter and used.
*FPC Board An FPC board for evaluation was prepared by providing Cu wiring (8 μm t-Sn plating) with a terminal pitch (L/S=1/1) of 20 μm on a polyimide film (38 μm t-S'perflex base material).
*Glass substrate An ITO pattern glass substrate (manufactured by Corning) was prepared as a glass substrate for evaluation. The outer dimensions of this glass substrate were 30 mm × 50 mm, the thickness was 0.5 mm, the width of the mounting area corresponding to the frame portion where the FPC substrate was to be anisotropically conductively connected was 0.5 mm, and Ti/Al wiring (thickness 0.3 μm) was provided within the mounting area.

(b) Implementation of the temporary attachment step, the placing step, and the thermocompression bonding step The anisotropic conductive films of Examples 1 to 7 and 10 and Comparative Examples 1 to 6 were temporarily attached to the terminal parts of the evaluation FPC board arranged on the mounting stage from the insulating resin layer side, the anisotropic conductive film of Example 9 was temporarily attached from the conductive particle-containing layer side, and the anisotropic conductive film of Example 8 was directly temporarily attached. The temporarily attached anisotropic conductive films were aligned and placed on the mounting area of the glass substrate, and a thermocompression tool was used to apply heat and pressure from above the anisotropic conductive film (180° C., 3.5 MPa, 6 seconds, thermocompression tool descending speed 10 mm/sec, stage temperature 40° C.) to obtain a connection body.

When performing the thermocompression bonding, as shown in FIG. 3, the positional relationship between the anisotropic conductive film 20, the FPC board 10 as the first electronic component, and the glass board 30 as the second electronic component "(a) mounting width, (b) wiring area width, (c) first area width of the ACF, (d) thermocompression tool position, (e) thermocompression tool width, and (f) second area width of the ACF" was as specified in Table 1.

(3) Evaluation of the Connection The connection obtained was evaluated and comprehensively judged for the following "curing reaction rate of the second region of the ACF,""conductivityresistance,""insulationresistance,""particle capture ability," and "adhesive strength." The evaluation results and comprehensive judgment results are shown in Table 1.

(a) Curing reaction rate of the second region of the ACF The curing reaction rate of the second region of the ACF in the evaluation connection (i.e., the region not thermocompressed) was evaluated. Specifically, the curing reaction rate of the second region of the ACF in each evaluation connection was calculated based on the peak intensity of the fully cured material and the uncured material by the IR method. The curing reaction rate was evaluated according to the following criteria.

(Evaluation Criteria for Curing Reaction Rate of the Second Region of ACF)
A (Good): 80% or more B (No problem): 60% or more but less than 80% C (Not good): Less than 60%

(b) Conduction Resistance The conduction resistance of each evaluation connection was evaluated. Specifically, a digital multimeter (product number: Digital Multimeter 7555, manufactured by Yokogawa Electric Corporation) was used to measure the resistance value when a current of 1 mA was applied by the four-terminal method. The conduction resistance was evaluated according to the following criteria.

(Conductive resistance evaluation criteria)
A (Good): Less than 2Ω B (No problem): 2Ω to 4Ω C (Not good): More than 4Ω

(c) Insulation Resistance The insulation resistance of each evaluation connection was evaluated. Specifically, the resistance between adjacent lines was measured using a high resistance meter (product number: High Resistance Meter 4339B, manufactured by Agilent Technologies) by the two-terminal method when an applied voltage of 25 V was set. The insulation resistance was evaluated according to the following criteria.

(Insulation resistance evaluation criteria)
AA (more preferable): 10 ¹² Ω or more A (preferable): 10 ¹¹ Ω or more and less than 10 ¹² Ω B (no problem): 10 ⁹ Ω or more and less than 10 ¹¹ Ω C (not acceptable): less than 10 ⁹ Ω

(d) Particle capture (minimum connection area)
Particle capture was evaluated by estimating the minimum connection area (the area of a terminal where five or more conductive particles are captured). Specifically, a TEG with linear wiring formed in the X direction was used. The indentations were counted using an optical microscope, and a calibration curve was created with the horizontal axis representing the connection area and the vertical axis representing the number of captured particles.

(Particle Capture Evaluation Criteria)
A (preferable): 200 μm2 or ^more and less than 1000 ^μm2 B (no problem): 1000 μm2 ^or more and 2000 ^μm2 or less C (not acceptable): more ^than 2000 μm2

(e) Adhesive strength The adhesive strength of each evaluation connection was evaluated. Specifically, it was measured using a tensile tester (RTC 1201 , A&D Co., Ltd. ). The evaluation FPC board was cut to a width of 1 cm, and the evaluation FPC board was pulled up in a 90 degree direction from the evaluation glass board at a speed of 50 mm/sec. The force required for peeling was measured as adhesive strength (N /cm ).
The adhesive strength was evaluated according to the following criteria.

(Adhesive Strength Evaluation Criteria)
A (preferable): greater than 8N /cm B (no problem): 5N /cm to 8N /cm C (not acceptable): less than 5N /cm

[Discussion of evaluation results]
From the results in Table 1, the connections of Examples 1 to 10 showed good results in each evaluation item of the curing reaction rate of the second region of the ACF, the conduction resistance, the insulation resistance, the particle capture property, and the adhesive strength. In particular, in the case of Example 3, even if the wiring region width of the glass substrate is as narrow as 0.1 mm, it was found that the evaluation results of the conduction resistance, the insulation resistance, the conductive particle capture property, and the adhesive strength of the manufactured connection were all at a level that would not cause any practical problems.

The connection body of Comparative Example 1 was rated "C" for electrical resistance. Comparing with Example 4, this is thought to be due to the small proportion of the ACF first region width and the large proportion of the ACF second region width. Comparing the results of Comparative Example 1 and Example 4, it was found that it is preferable for the proportion of the ACF first region width to the total width of the anisotropic conductive film to be 25% or more (the proportion of the ACF second region width to be less than 75%).

The connection in Comparative Example 2 was rated "C" for conduction resistance. This is believed to be due to the thermocompression tool position being too far from the edge of the display. Comparing the results of Comparative Example 2 and Example 5, it was found that a thermocompression tool position of 70% or less is preferable.

In Comparative Example 3, it was not possible to produce a connection body. This is thought to be because the width of the thermocompression bonding tool was about four times the mounting width, and the bottom surface of the thermocompression bonding tool made a one-sided contact with the FPC board without making surface contact. Comparing the results of Comparative Example 3 and Example 6, it was found that it is preferable for the thermocompression bonding tool width to be three times the mounting width or less.

The connection body manufactured under the conditions of Comparative Example 4 had problems with the evaluation item of adhesive strength. This was thought to be due to the mounting width of 0.1 mm, which reduced the adhesive width between the glass substrate and the anisotropic conductive film, resulting in a decrease in connection strength. Comparing the results of Comparative Example 4 and Example 7, it was found that there were no problems with adhesive strength if the mounting width was 0.2 mm or more.

Under the conditions of Comparative Example 5, it was not possible to produce a connection. This is thought to be because the thermocompression bonding tool position was a negative value of -10%, and the thermocompression bonding tool came into contact with the display section, causing the bottom surface to make partial contact with the FPC board without making surface contact.

The connection body manufactured under the conditions of Comparative Example 6 had a problem with the evaluation item of insulation resistance. The anisotropic conductive film of Comparative Example 6 had a conductive particle number density of 20,000 particles/ ^mm2, which is thought to be the cause of the problem because the conductive particles were too dense. Comparing the results of Comparative Example 6 with those of Examples 9 and 10, it was found that no problem occurs in insulation resistance if the conductive particle number density is 6,000 particles/mm2 or ^more and 16,000 particles/mm2 or ^less .

In the method for manufacturing a connection body of the present invention, an anisotropic conductive film is temporarily attached to a terminal portion of a first electronic component such as an FPC board. This eliminates the need to make the width of the anisotropic conductive film used equal to or less than the width of the mounting area of a second electronic component such as a display panel. Therefore, an anisotropic conductive film whose width is greater than the width of the wiring area of the second electronic component and has stable anisotropic conductive properties can be used. Therefore, the anisotropic conductive film can be temporarily attached using a conventional mounting device, and temporary attachment with particularly high placement accuracy is not required. In this way, not only is it unnecessary to introduce a new mounting device, but it is also possible to avoid significant modifications to the conventional mounting device. As a result, it is possible to avoid the evaluation results of the specified evaluation items (conductive resistance, insulation resistance, conductive particle capture, adhesive strength) of the manufactured connection body being reduced to a level that cannot be practically applied. Therefore, the method for manufacturing a connection body of the present invention is useful when anisotropically conductively connecting the terminal portion of a first electronic component such as an FPC board to a narrow-width mounting area of a second electronic component such as a display panel.

REFERENCE SIGNS LIST 10 First electronic component 11 Terminal portion 20 Anisotropic conductive film 20X First region 20Y Second region 21 Binder resin layer 22 Conductive particles 23 Conductive particle-containing layer 24 Insulating resin layer 30 Second electronic component (e.g., display panel)
30a Mounting area 31 Wiring area 40 Thermocompression bonding tool 100 Connection body D Distance La from one side of the binder resin layer of the anisotropic conductive film to the conductive particles Layer thickness of the binder resin layer (a) Mounting width (b) Wiring area width (c) First area width of the anisotropic conductive film (d) Thermocompression bonding tool position (e) Thermocompression bonding tool width (f) Second area width of the anisotropic conductive film

Claims (14)

A method for manufacturing a connection body in which a terminal portion of a first electronic component is anisotropically conductively connected to a wiring region within a mounting region of a second electronic component via an anisotropic conductive film, the method comprising the steps of:
a temporary attachment step of temporarily attaching an anisotropic conductive film to a first electronic component;
a placing step of placing the anisotropic conductive film temporarily attached to the first electronic component on a wiring region of the second electronic component;
a thermocompression bonding step of thermocompression bonding from the first electronic component side with a thermocompression bonding tool, wherein the position of the thermocompression bonding tool is 5% or more and 70% or less of the mounting area width,
the anisotropic conductive film has a conductive particle-containing layer including a binder resin layer and conductive particles contained therein, the conductive particles being regularly arranged in the conductive particle-containing layer, the conductive particles being unevenly distributed on one side of the binder resin layer and on one side of the conductive particle-containing layer facing a second electronic component,
the anisotropic conductive film has a first region sandwiched between opposing surfaces of the second electronic component and the first electronic component, and a second region adjacent to the first region and facing the first electronic component but not facing the second electronic component ;
A method for manufacturing a connection body, wherein the mounting width is 1 mm or less, the wiring region width is 0.1 mm or more, and the first region width is less than the mounting width and is 25% or more of the anisotropic conductive film width . 2. The method according to claim 1, wherein the width of the second region is 75% or more of the width of the anisotropic conductive film. 3. The method according to claim 1, wherein the curing reaction rate of the film is 60% or more by thermocompression bonding. The method according to any one of claims 1 to 3, wherein in the temporary attachment step, the first electronic component and the anisotropic conductive film are flush with each other at their terminal ends. 5. The manufacturing method according to claim 1, wherein in the placing step, a first region of the anisotropic conductive film temporarily attached to the first electronic component is aligned with a wiring region of the second electronic component. 6. The manufacturing method according to claim 1, wherein, when a distance from one surface of the binder resin layer in the conductive particle-containing layer of the anisotropic conductive film to the conductive particles is D and a layer thickness of the binder resin layer is La, a ratio (%) of the distance D to the layer thickness La [(D/La) x 100] is -5% or more and 40% or less . The method according to claim 6, wherein the ratio is −5% or more and 5% or less. The manufacturing method according to any one of claims 1 to 7, wherein in the temporary attachment step, when the anisotropic conductive film is temporarily attached to the first electronic component, the temporary attachment is performed from a side on which conductive particles are not unevenly distributed. The method according to any one of claims 1 to 8 , wherein the anisotropic conductive film has a structure in which an insulating resin layer is further laminated on a conductive particle-containing layer. The manufacturing method according to claim 9 , wherein in the temporary attachment step, the anisotropic conductive film is temporarily attached to the first electronic component such that the insulating resin layer side is positioned on the first electronic component side. The manufacturing method according to any one of claims 1 to 10 , wherein the width of the thermocompression bonding tool is greater than the width of the anisotropic conductive film. 12. The method according to claim 1, wherein the width of the thermocompression bonding tool is 0.8 to 3 times the mounting width of the second electronic component. 13. The manufacturing method according to claim 1, wherein the first electronic component is an FPC board, and the second electronic component is a display panel. A connection body in which a terminal portion of a first electronic component and a wiring region within a mounting region of a second electronic component are anisotropically conductively connected via an anisotropic conductive film having a conductive particle-containing layer in which conductive particles are contained in a binder resin layer, the conductive particles being regularly arranged in the conductive particle-containing layer, the conductive particles being unevenly distributed on one side of the binder resin layer and unevenly distributed on one side of the conductive particle-containing layer facing the second electronic component ,
the anisotropic conductive film includes a first region sandwiched between opposing surfaces of the second electronic component and the first electronic component, and a second region adjacent to the first region, facing the first electronic component but not facing the second electronic component ;
A connection body having a mounting width of 1 mm or less, a wiring region width of 0.1 mm or more, and a first region width of less than the mounting width and greater than 25% of the width of the anisotropic conductive film.

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