TWI647886B - Anisotropic conductive film, connection structure, connection structure manufacturing method and connection method - Google Patents

Abstract

The method for manufacturing the connection structure of the present invention is to insert an anisotropic conductive connection layer between a terminal of a flexible display and a terminal of the electronic component, and connect the flexible display to the electronic component. And conducting, the step of: mounting the electronic component on the terminal by aligning a terminal of the electronic component with a terminal provided on the flexible display via the anisotropic conductive connection layer And a connecting step of: pressing the electronic component on the flexible display, and connecting the terminal provided on the flexible display to the terminal of the electronic component via the anisotropic conductive connecting layer; The conductive particles in the anisotropic conductive connection layer conduct the terminals. The compressive hardness at the time of 30% compression deformation of the above conductive particles is 150 to 400 Kgf/mm ² .

Description

 Anisotropic conductive film, connection structure, connection structure manufacturing method and connection method  

The present invention relates to an anisotropic conductive connecting material used for constructing an electronic component such as a flexible printed circuit board or a semiconductor component for a flexible display, and using an anisotropic conductive connecting layer to be flexible A connection structure in which a physical display is connected to an electronic component, a connection method in which a flexible display is connected to an electronic component using an anisotropic conductive connection layer, and a method of manufacturing a connection structure using the connection method.

As a technique for mounting an electronic component such as a semiconductor element on a substrate, for example, a flip chip mounting method in which an electronic component is mounted on a substrate in a so-called face down state is widely used. In the flip chip mounting method, in order to improve the connection reliability and the like, an anisotropic conductive film is inserted between the terminal of the electronic component and the terminal provided on the substrate, and electrical and mechanical connection by the anisotropic conductive film is performed. The anisotropic conductive film is one in which conductive particles are dispersed in an adhesive containing a resin or the like. The conductive particles are, for example, particles obtained by subjecting the resin particles to nickel plating or gold plating.

In the above-described method, for example, in Patent Document 1, the terminal surface of the electronic component or the terminal surface of the wiring substrate is a flat surface, and the conductive particles are uniformly crushed, whereby the terminals of the electronic component are placed on the terminal. The electrical connection of the terminals of the wiring substrate is good.

Moreover, the mounting method is also used for a liquid crystal display or a flexible display. The liquid crystal display uses a glass substrate having a Young's modulus of up to 72 GPa and is not easily deformed, and is easily damaged by external extrusion or the like. On the other hand, a flexible display made of a soft plastic for a substrate is very thin and flexible, so that it can be bent and is not easily broken, and can be used for an electronic paper or a roll up screen.

In a flexible display, a transparent electrode (ITO or the like) in a display region is extended and connected to an electronic component such as an IC chip or a flexible printed circuit board at an end portion of a substrate made of plastic or the like. Terminal. In the flexible display, the terminal for connection is provided immediately below or in the vicinity of the display region, and the terminal is made finer and narrower in order to perform high-density mounting or the like. In the electrical connection of the terminal for miniaturization and narrow pitch, and the terminal of an electronic component or a flexible printed circuit board, an anisotropic conductive film is used as described above (for example, see Patent Document 2).

In a flexible display, since a flexible substrate such as polyimide or polyethylene terephthalate is used, a general anisotropic conductive film used in connection with an electronic component is used, and pressurized In the case of connection, there is a case where cracks occur in the terminal starting from the conductive particles, and the substrate is also cracked or cracked. For example, when an electronic component such as an IC chip is directly connected to a substrate of a flexible display, unlike a flexible printed circuit board having a wide wiring, an IC chip or the like becomes a bump of a terminal. In the presence of pressure, the pressure applied during the connection is also concentrated at one point, so that cracks are likely to occur.

In the flexible display, the mounting area of the electronic component is present immediately below or in the vicinity of the display portion. Therefore, compared with the case where the electronic component is mounted on the terminal of the wiring substrate as in the above-described Patent Document 1, Cracks are generated in the narrow structure area, and crack generation must be particularly suppressed. In the flexible display, if the terminal is cracked when the electronic component is connected, or the flexible substrate is broken, cracks or cracks may occur in the display portion, and thus the display portion is greatly affected. It is required to suppress the occurrence of cracks due to the connection of electronic parts or the cracking of the substrate.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2009-111043

Patent Document 2: Japanese Laid-Open Patent Publication No. 2009-242508

The present invention has been made in view of such prior circumstances, and an object thereof is to provide an anisotropic conductive connecting material which is provided with a terminal for a flexible display and a terminal of an electronic component by using an anisotropic conductive connecting material. When electrically connected, the terminal disposed on the flexible display or the flexible display itself may be prevented from cracking or cracking; a connecting structure connecting the flexible display and the electronic component using the anisotropic conductive connecting layer; A method of connecting a flexible display to an electronic component using an anisotropic conductive connection layer, and a method of manufacturing the bonded structure using the connection method.

The method for manufacturing a connection structure according to the present invention which achieves the above object is to insert an anisotropic conductive connection layer between a terminal of a flexible display and a terminal of an electronic component, and connect and electrically connect the flexible display to the electronic component. The method includes the steps of: mounting the electronic component on the flexible display such that the terminal of the electronic component is opposed to the terminal provided on the flexible display via the anisotropic conductive connection layer; And connecting step: pressing the electronic component on the flexible display, and connecting the terminal disposed on the flexible display to the terminal of the electronic component through the anisotropic conductive connecting layer and conducting the conductive particle in the anisotropic conductive connecting layer The terminals are turned on; the compression hardness at 30% compression deformation of the conductive particles is 150 to 400 Kgf/mm ² .

The connection method of the present invention for achieving the above object is to connect a terminal provided on a flexible display to a terminal of an electronic component by an anisotropic conductive connection layer, and has the following steps: a mounting step: interlacing The conductive conductive connection layer mounts the electronic component on the flexible display such that the terminal of the electronic component faces the terminal provided on the flexible display; and the connecting step: pressurizing the electronic component to the flexible display, and utilizing The anisotropic conductive connection layer connects the terminal disposed on the flexible display to the terminal of the electronic component and conducts the terminals through the conductive particles in the anisotropic conductive connection layer; when the conductive particles are 30% compressed and deformed The compression hardness is 150 to 400 Kgf/mm ² .

The anisotropic conductive connecting material of the present invention which achieves the above object connects the terminal provided on the flexible display to the terminal of the electronic component, and has a compression hardness of 150 to 400 Kgf/mm ² when the adhesive contains 30% compression deformation. Conductive particles.

The connection structure system of the present invention for achieving the above object inserts an anisotropic conductive connection layer between a terminal of the flexible display and a terminal of the electronic component, and connects and electrically connects the flexible display and the electronic component, and anisotropically conductive The compressive hardness at 30% compression deformation of the conductive particles in the layer is 150 to 400 Kgf/mm ² .

According to the present invention, the compression hardness at the time of 30% compression deformation of the conductive particles contained in the insulating adhesive for the anisotropic conductive connecting material is 150 to 400 Kgf/mm ² , and even the flexibility is obtained. When the display is connected to the electronic component, the conductive particles are deformed, and the contact area between the conductive particles and the terminals of the flexible display is enlarged, and cracks in the terminals of the flexible display can be prevented, and the flexible display itself can be suppressed. Cracks are also generated, or cracks.

1‧‧‧membrane layer

2‧‧‧Release film

3‧‧‧ Anisotropic conductive film

4‧‧‧Insulating adhesive

5‧‧‧Electrical particles

10, 20‧‧‧ Connection structure

10a, 20a‧‧‧ Display Department

10b, 20b‧‧‧ Construction Department

11‧‧‧Flexible display

12‧‧‧ IC chip

12a, 13a, 14a‧‧‧ terminals

13‧‧‧Flexible printed circuit boards

14‧‧‧Flexible film

15‧‧‧Display media layer

16‧‧‧ Sealing Department

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a film laminate to which the present invention is applied.

Fig. 2 is a graph showing the relationship between the compression shift and the load calculated from the compression hardness at the time of 30% compression deformation of the conductive particles.

3 is a view showing a connection structure in which a flexible display and an electronic component are connected by an anisotropic conductive film, (A) is a plan view of the connection structure, and (B) is a cross-sectional view of the connection structure.

Fig. 4 is a cross-sectional view showing a connecting portion of a terminal of a flexible film and a terminal of an electronic component.

Fig. 5 is a plan view showing a connection structure in which two IC chips and a flexible printed circuit board are connected to a flexible display by an anisotropic conductive film.

Hereinafter, the anisotropic conductive connecting material, the connecting structure, the method of manufacturing the connecting structure, and the connecting method to which the present invention is applied will be described in detail with reference to the drawings. In addition, the present invention is not limited to the following detailed description unless otherwise specified. The description of the embodiments of the present invention is carried out in the following order.

1. Anisotropic conductive connecting material

2. Connection structure, connection method of connection structure, connection method

<Anisotropic conductive connecting material>

The anisotropic conductive connecting material is inserted between the terminal of the flexible display and the terminal of the electronic component, and the flexible display is connected to the electronic component and turned on. Examples of such an anisotropic conductive connecting material include a film-shaped anisotropic conductive film or a slurry-like anisotropic conductive connecting paste. In the present application, an anisotropic conductive film or an anisotropic conductive connecting paste is defined as an "anisotropic conductive connecting material". Hereinafter, an anisotropic conductive film will be described as an example.

As shown in FIG. 1, the film laminate 1 is usually formed by laminating an anisotropic conductive film 3 which is an anisotropic conductive connection layer on a release film 2 which is a release substrate.

The release film 2 is, for example, a pair of PET (Poly Ethylene Terephthalate, polyethylene terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1, poly-4-methylpentene- 1) A PTFE (Polytetrafluoroethylene) or the like is coated with a release agent such as an anthrone.

The anisotropic conductive film 3 is one in which the conductive particles 5 are dispersed in an insulating adhesive (adhesive) 4 containing a film-forming resin, a thermosetting resin, and a curing agent. The anisotropic conductive film 3 is formed into a film shape on the release film 2.

The film-forming resin is preferably a resin having an average molecular weight of about 10,000 to 80,000. Examples of the film-forming resin include various resins such as an epoxy resin, a deformed epoxy resin, an urethane resin, and a phenoxy resin. Among them, a phenoxy resin is preferred from the viewpoints of a film formation state, connection reliability, and the like. When the content of the film-forming resin is too small, the film cannot be formed, and if it is too large, the resin for electrical connection is not easily removed. Therefore, it is 20 to 80 parts by mass, preferably 40, per 100 parts by mass of the insulating adhesive 4. ~70 parts by mass.

The hardening component is not particularly limited as long as it has fluidity at normal temperature, and examples thereof include commercially available epoxy resins and acrylic resins.

The epoxy resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a naphthalene type epoxy resin, a biphenyl type epoxy resin, a phenol novolak type epoxy resin, a bisphenol type epoxy resin, and a quinoid type. Epoxy resin, trisphenol methane type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, and the like. These may be used alone or in combination of two or more.

The acrylic resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include an acrylic compound and a liquid acrylate. Specific examples thereof include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and trimethylolpropane. Triacrylate, dimethylol tricyclodecane acrylate, 1,4-butanediol tetraacrylate, 2-hydroxy-1,3-dipropenyloxypropane, 2,2-bis[4-( Propylene methoxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, isocyanide Uric acid tris(propylene methoxyethyl ester), urethane acrylate, epoxy acrylate, and the like. These may be used alone or in combination of two or more.

As the thermosetting resin, an epoxy resin or an acrylic resin is preferably used.

Examples of the latent curing agent include various curing agents such as a heat curing type and a UV curing type. The latent curing agent usually does not react, and is activated by various trigger sources selected according to the use such as heat, light, pressure, and the like, and the reaction is started. A method for activating a heat-active latent curing agent: a method of forming an active species (cation or anion) in a dissociation reaction by heating or the like; stably dispersing in an epoxy resin at room temperature, at a high temperature and a ring A method in which an oxygen resin is compatible and melted, and a hardening reaction is started; a method in which a molecular sieve-sealed hardener is melted at a high temperature to start a hardening reaction; a microcapsule melting and hardening method is used. The thermally active latent curing agent is an imidazole, an anthraquinone, a boron trifluoride-amine complex, an onium salt, an amine imine, an amine salt, a dicyandiamide, or the like, or the like, and the like They may be used singly or in combination of two or more kinds. Among them, a microcapsule type imidazole-based latent curing agent is preferred.

Further, the anisotropic conductive film 3 may further contain a decane coupling agent. The decane coupling agent is not particularly limited, and examples thereof include an epoxy group, an amine group, a thiol group, a thio group, and a urea group. By adding a decane coupling agent, the interface between the organic material and the inorganic material can be improved.

The compression hardness (K value) at 30% compression deformation of the conductive particles 5 is 150 to 400 Kgf/mm ² (1.50 to 4.00 GPa), preferably 150 to 350 Kgf/mm ² (1.50 to 3.50 GPa). The index of the hardness of the conductive particles 5 is a K value calculated from a load required to perform 30% compression deformation on the particle size in an unloaded state when a load is applied to one particle to deform the particle. The 30% compression deformation refers to a state in which the conductive particles 5 are deformed in one direction, and the particle diameter 2R (mm) of the conductive particles is deformed by 30% shorter than the original particle diameter, that is, the conductive particles. The particle size 2R is a deformed state of 70% of the original particle diameter. The smaller the K value, the softer the particles.

The compression hardness (K value) at the time of 30% compression deformation of the conductive particles 5 was calculated by the following formula (1).

Here, in the formula (1), F and S are respectively a load value (Kgf) and a compression shift (mm) at 30% of compression deformation of the conductive particles, and R is a radius of the semiconductor particles (mm).

The K value is measured, for example, by the following measurement method. Specifically, first, conductive particles are spread on a steel sheet having a smooth surface at room temperature. Next, one conductive particle is selected from the dispersed conductive particles. Then, a smooth end surface of a 50 μm diameter cylinder made of diamond made of a micro compression tester (for example, PCT-200 type: manufactured by Shimadzu Corporation) is pressed against the selected one of the conductive particles to be compressed. The conductive particles. At this time, the compression load is electrically detected as an electromagnetic force, and the compression displacement is electrically detected as a displacement by the actuation transformer. Here, the "compression shift" refers to a value (mm) obtained by subtracting the length of the short diameter of the conductive particles after deformation from the particle diameter of the conductive particles before deformation. Thereafter, other conductive particles on the steel sheet are selected, and the compression load and the compression shift are also measured for the selected conductive particles. For example, the measurement of compressive deformation of 10 conductive particles with respect to different compression loads is performed.

The relationship between compression shift and load is shown in Figure 2. According to the relationship shown in Fig. 2, the load value F (kgf) is calculated from the compression shift S (mm) at 30% compression of the conductive particles. Then, the compression hardness K value at the time of 30% compression is calculated by the formula (1) by the load value F (kgf) and the compression shift S (mm).

The compression hardness at the time of 30% compression deformation of the conductive particles 5 is 150 to 400 Kgf/mm ² , and if the substantially spherical particles are pressed, they are deformed by the load, thereby being as follows When the anisotropic conductive film 3 is inserted between the terminal of the flexible display and the terminal of the electronic component, and the terminals are connected to each other and turned on, they are deformed by being slightly crushed even after being compressed. Therefore, the conductive particles 5 are not in surface contact with respect to the terminals of the flexible display, and the pressure per unit area transmitted to the terminals is reduced, and the partial pressure applied to the terminals can be dispersed, and the terminals can be prevented. Cracks are generated, or the flexible display itself is broken. When the K value of the conductive particles 5 is too small and too soft, the on-resistance value of the connection portion is unstable, so that it is 150 Kgf/mm ² or more. By setting it as 150 to 400 Kgf/mm ² , cracking of the terminal and cracking or cracking of the flexible display itself can be prevented, and the on-resistance value can also be lowered.

As the conductive particles 5, particles of various metals such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, gold, or metal alloys can be used, and metal oxides, carbon, graphite, glass, ceramics, and plastics can be used. The surface of the particles is coated with a metal, or an insulating film is applied to the surface of the particles. When the surface of the resin particle is coated with a metal, examples of the resin particle include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile-styrene (AS) resin, a benzoguanamine resin, and the like. Particles such as a vinyl benzene resin or a styrene resin. The conductive particles 5 are composed of these materials and satisfy the above K value.

The average particle diameter of the conductive particles 5 is preferably from 1 to 20 μm, more preferably from 2 to 10 μm, from the viewpoint of connection reliability. By setting the average particle diameter of the conductive particles 5 to a range of 1 μm to 20 μm, the conductive particles 5 can be electrically connected even if they are compressed and deformed by pressurization.

Further, the average particle density of the conductive particles 5 in the insulating adhesive 4 is preferably from 1,000 to 50,000/mm ² , more preferably from 3,000 to 30,000/mm, from the viewpoint of connection reliability and insulation reliability. ² .

The film laminate 1 having such a configuration can be produced by dissolving the above-mentioned insulating adhesive (adhesive) 4 in a solvent such as toluene or ethyl acetate to produce an anisotropy in which the conductive particles 5 are dispersed. The electrically conductive composition is applied to the release film 2 having releasability so as to have a desired thickness, and is dried to remove the solvent to form the anisotropic conductive film 3.

Further, the film laminate 1 is not limited to the configuration in which the anisotropic conductive film 3 is formed on the release film 2, and the insulating layer 3 may be laminated, for example, only by the insulating adhesive 4. Resin layer (NCF: Non Conductive Film).

Further, the film laminate 1 may be configured such that a release film is provided on the opposite side of the surface of the anisotropic conductive film 3 on which the release film 2 is laminated.

The compression hardness at the time of 30% compression deformation of the conductive particles 5 in the anisotropic conductive film 3 of the film laminate 1 having the above-described constitution is 150 to 400 Kgf/mm ² , whereby the pressure is applied. The roughly spherical particles are deformed by the load. Therefore, in the anisotropic conductive film 3, when the terminal provided on the flexible flexible display is connected and electrically connected to the terminal of the electronic component, it is deformed by being slightly crushed by compression. The terminal of the flexible display is not in surface contact with dots, and the contact area is increased, so that the pressure applied to the terminal is dispersed, and cracking of the terminal or cracking or cracking of the flexible display itself can be suppressed. .

<Connection structure, method of manufacturing the connection structure, and connection method>

Next, a connection method in which the terminals of the flexible display and the terminals of the electronic component are electrically connected and connected using the anisotropic conductive film 3, a connection structure manufactured thereby, and a method of manufacturing the connection structure will be described.

The connection structure 10 shown in FIG. 3 is connected to the flexible display 11 to mechanically and electrically connect the IC chip 12 as an electronic component for driving the flexible display 11 and to be electrically connected to the outside. Flexible printed circuit board 13. The connection structure 10 has a display portion 10a that displays an image or the like, and a configuration portion 10b that mechanically and electrically connects the IC chip 12 and the flexible printed circuit board 13.

The flexible display 11 has two flexible films 14 of a front panel and a back panel, and a display medium layer 15 such as a microcapsule layer or a liquid crystal layer is disposed between the two flexible films 14, and the periphery of the display medium layer 15 It is sealed by the sealing portion 16 using the sealing material. The Young's modulus of the flexible film 14 is 10 GPa or less, preferably 2 to 10 GPa, and more preferably 3 to 5 GPa. The Young's modulus is a fixed number of substances that are calculated from the strain (deformation rate) per unit generated when a stress is applied to a substance and deformed.

If the Young's modulus is large, it is not easily deformed with respect to stress, and if the Young's modulus is small, it is easily deformed.

The flexible film 14 has a small Young's modulus and is easily deformed with respect to a load compared to a glass substrate of about 72 GPa. The flexible film 14 is exemplified by polyimide or polyethylene terephthalate. As shown in FIG. 4, the terminal 14a of the flexible film 14 provided on the back panel, and the terminal 12a of the IC chip 12 or the terminal 13a of the flexible printed circuit board 13 are electrically connected by the compressively deformed conductive particles 5. connection.

The connection structure 10 can be manufactured by the following connection method. First, the mounting step of inserting the anisotropic conductive film 3 between the "terminal 14a of the flexible film 14" and the "terminal 12a of the IC chip 12 and the terminal 13a of the flexible printed circuit board 13" is performed. The IC 14 and the flexible printed circuit board 13 are mounted on the flexible film 14 so that the terminal 14a of the flexible film 14 faces the terminal 12a of the IC chip 12 and the terminal 13a of the flexible printed circuit board 13. on. Next, a connection step is performed in which the IC film 12 and the flexible printed circuit board 13 are pressed against the flexible film 14, and the terminal 14a and the IC chip 12 provided on the flexible film 14 are bonded by the anisotropic conductive film 3. The terminal 12a and the terminal 13a of the flexible printed circuit board 13 are connected and electrically connected via the conductive particles 5 in the anisotropic conductive film 3.

In the method of manufacturing the bonded structure 10, for example, a case where the film laminated body 1 including the anisotropic conductive film 3 is used as an insulating adhesive using a thermoplastic resin as a hardening component will be described. 4 contains conductive particles 5 . First, in the mounting step, the anisotropic conductive film of the film laminate 1 is connected to the terminal 14a of the flexible film 14 and the terminal 12a of the IC chip 12 and the terminal 13a of the flexible printed circuit board 13. 3 is placed so as to be on the terminal 14a side of the flexible film 14, and the release film 2 is peeled off, and only the anisotropic conductive film 3 is used, and then the anisotropic conductive film 3 is adhered to the terminal 14a. The adhesion is performed by, for example, heating at a temperature at which the thermosetting resin component contained in the anisotropic conductive film 3 is not cured while being slightly pressurized. Thereby, the anisotropic conductive film 3 is positioned and fixed to the terminal 14a of the flexible film 14.

Next, the IC wafer 12 and the flexible printed circuit board 13 are mounted on the anisotropic conductive film 3. The mounting of the electronic component is performed by confirming the positional alignment state of the anisotropic conductive film 3, and the terminal 14a of the flexible film 14 and the terminal 12a of the IC wafer 12 are flexible. The IC chip 12 and the flexible printed circuit board 13 are mounted on the flexible film 14 via the anisotropic conductive film 3 so that the terminals 13a of the printed circuit board 13 face each other.

Next, the connecting step of mechanically and electrically connecting the flexible film 14 of the flexible display 11 and the IC chip 12 and the flexible printed circuit board 13 is performed by using a heatable and pressurizable extrusion head from the IC chip 12. On the upper surface of the flexible printed circuit board 13, the IC wafer 12 and the flexible printed circuit board 13 are pressed while heating the flexible film 14, and the anisotropic conductive film 3 is cured to pass through the conductive particles 5. The terminal 14a of the flexible film 14 is electrically connected to the terminal 12a of the IC chip 12 and the terminal 13a of the flexible printed circuit board 13, and the flexible film 14 and the IC chip 12 are flexibly covered by the insulating adhesive 4. The printed circuit board 13 is mechanically connected, whereby the connection structure 10 in which the IC chip 12 and the flexible printed circuit board 13 are connected to the flexible display 11 can be obtained.

The connection step is carried out under the condition that the heating temperature is a temperature higher than the hardening temperature of the thermosetting resin contained in the anisotropic conductive film 3, and the thermally melted anisotropic conductive film is removed from the terminal 14a and the terminals 12a and 13a. 3. Pressurization is performed at a pressure at which the conductive particles 5 can be held. Thereby, the flexible film 14 and the IC wafer 12 and the flexible printed circuit board 13 are electrically connected by the conductive particles 5, and are mechanically connected by an insulating adhesive (adhesive) 4. The specific conditions of temperature and pressure are about 120 ° C ~ 150 ° C, and the pressure is about 1 MPa ~ 5 MPa.

In the connecting step, the IC wafer 12 and the flexible printed circuit board 13 are pressed toward the flexible film 14 by the extrusion head, and the conductive particles 5 inserted between them are compressed and deformed. The terminal 14a of the flexible film 14 is not in point contact but is in surface contact, and the contact area with the terminal 14a is increased. Thereby, in the connecting step, the pressure per unit area transmitted from the conductive particles 5 to the terminal 14a is reduced, and the partial pressure applied to the terminal 14a can be dispersed, and the crack of the terminal 14a can be prevented, and the deflection can be prevented. The film 14 also cracks or ruptures.

The method for manufacturing the bonded structure 10 as described above is such that the compressive hardness at the time of 30% compression deformation of the conductive particles 5 contained in the anisotropic conductive film 3 is 150 to 400 Kgf/mm ² , which can be prevented. When the flexible film 14 is connected to the electronic component, particularly when it is connected to the IC wafer 12 in which the terminal is dispersed, the terminal 14a of the flexible film 14 is cracked, and the flexible film 14 itself is prevented from being cracked or broken. The anisotropic conductive film 3 is inserted between the terminal 14a of the flexible film 14 and the terminal 12a of the IC chip 12 and the terminal 13a of the flexible printed circuit board 13. Therefore, in the method of manufacturing the connection structure 10, the terminal 14a of the flexible film 14 can be prevented from being cracked, and the flexible film 14 itself can be prevented from being cracked, and the electronic component can be constructed without being broken. On the flexible film 14.

Therefore, the manufacturing method of the connection structure 10 is in the case where the electronic component mounting region is present in the vicinity of the display portion 10a of the flexible display 11 having the display medium layer 15 or directly under the display portion 10a, even if it is configured The narrow portion of the portion 10b does not cause cracks in the terminal 14a of the flexible film 14, and does not cause cracks in the flexible film 14 itself, and does not break, so that cracks or cracks are not delayed. The display unit 10a can prevent the display of an image or the like generated on the display medium layer 15 from being affected.

The connection structure 10 is configured to mechanically and electrically connect one IC chip 12 and the flexible printed circuit board 13 to the flexible display 11 . However, the connection structure 10 is not limited thereto, and may be as shown in FIG. 5 . The structure 20 is connected. The connection structure 20 is configured to mechanically and electrically connect the two IC chips 12 and the flexible printed circuit board 13 to the flexible display 11 by the anisotropic conductive film 3. The connection structure 20 has a display portion 20a that displays an image generated by a display medium layer (not shown), and a configuration portion 20b that mechanically and electrically separates the IC chip 12 and the flexible printed circuit board 13. Connect the assembly. Similarly to the above-described connection structure 10, the connection structure 20 does not cause cracks in the terminal 14a of the flexible film 14, and does not cause the flexible film 14 itself to be broken.

Further, the connection structures 10 and 20 do not need to be reinforced to prevent cracks in the terminals 14a of the flexible display 11, and there is no change from the manufacturing steps of the conventional flexible display 11, and the manufacturing cost can be prevented from being changed. high.

The connection structures 10 and 20 are not limited to the above-described flexible display, and may be an electronic component such as an IC chip 12 or a flexible printed circuit board 13 to which a flexible substrate such as a flexible film is connected.

Further, the electronic component is not limited to the IC chip 12 or the flexible printed circuit board 13, and may be other electronic components. For example, a semiconductor element such as a semiconductor wafer or a wafer capacitor other than an IC wafer such as an LSI (Large Scale Integration) wafer, a liquid crystal driving semiconductor package material (COF: Chip On FiLm), or the like can be cited. Further, the electronic component may be mounted on the flexible display 11 in two or more. The mounting position of the electronic component is not limited to FIG. 4 and FIG. 5, and may be directly under the display portions 10a and 20a.

The present invention has been described above, and the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

Example

Next, specific embodiments of the present invention will be described based on actual experimental results, but the present invention is not limited to the embodiments.

<Production of an anisotropic conductive film>

(Examples 1 to 5)

In Example 1 to Example 5, 30 parts by mass of a phenoxy resin (YP50, manufactured by Nippon Steel Chemical Co., Ltd.) as a film-forming resin, and a liquid epoxy resin (EP-) were added so as to have a solid content of 50%. 828, manufactured by Mitsubishi Chemical Corporation, 20 parts by mass, an imidazole-based latent curing agent (Novacure 3941HP, manufactured by Asahi Kasei E-MATERIALS Co., Ltd.), a decane coupling agent (A-187, manufactured by Momentive Performance Materials Co., Ltd.), 2 parts by mass, having a specific hardness An anisotropic conductive composition was prepared by using 10 parts by mass of conductive particles and toluene. Then, the anisotropic conductive composition was applied onto a release substrate using a bar coater, and toluene was dried in an oven to prepare an anisotropic conductive film having a film thickness of 20 μm.

The conductive particles are formed by forming a core portion of a resin, and plating the core portion with nickel (Ni) or nickel gold (NiAu). Specifically, the resin particles of the core are charged with benzammonium peroxide as a polymerization initiator in a solution in which the mixing ratio of divinylbenzene, styrene, and butyl methacrylate is adjusted, and uniform at a high speed. Heating was carried out while stirring, and polymerization was carried out to obtain a fine particle dispersion. Then, the microparticle dispersion is filtered and dried under reduced pressure to obtain a bulk which is an aggregate of fine particles. Further, by pulverizing the bulk, divinylbenzene-based resin particles having an average particle diameter of 3.0 μm of various hardnesses were obtained.

Then, the divinylbenzene-based resin particles obtained in the above manner are subjected to Ni plating or NiAu plating to prepare conductive particles obtained by plating Ni or NiAu on the divinylbenzene resin particles.

Conductive particles obtained by plating Ni on the divinylbenzene-based resin particles are supported by a palladium catalyst in 5 g of 3 μm of divinylbenzene-based resin particles by a dipping method. Next, an electroless nickel plating solution (pH 12, plating liquid temperature: 50 ° C) prepared from nickel sulfate hexahydrate, sodium hypophosphite, sodium citrate, triethanolamine, and cerium nitrate was used for the resin particles to perform electroless nickel plating. On the other hand, nickel-coated resin particles having a nickel plating layer (metal layer) having various phosphorus contents were formed as conductive particles (resin core-plated Ni particles). The average particle diameter of the obtained conductive particles is in the range of 3 to 4 μm.

The conductive particles obtained by subjecting the divinylbenzene-based resin particles to NiAu were mixed with 12 g of sodium chloroaurate dissolved in 1000 mL of ion-exchanged water to prepare 12 g of divinylbenzene-based resin particles to prepare an aqueous suspension. A gold plating bath was prepared by adding 15 g of ammonium thiosulfate, 80 g of ammonium sulfite, and 40 g of ammonium hydrogen phosphate to the obtained aqueous suspension. After 4 g of hydroxylamine was added to the obtained gold plating bath, the pH of the gold plating bath was adjusted to 9 by using ammonia, and the bath temperature was maintained at 60 ° C for about 15 to 20 minutes, thereby obtaining gold-plated nickel on the surface. Nickel film resin particles (resin core-plated NiAu particles) of a layer (metal layer). The average particle diameter of the obtained conductive particles is in the range of 3 to 4 μm.

The compression hardness at 30% compression deformation of the conductive particles is shown in Table 1, respectively. As described above, the compressive hardness at the time of 30% compression deformation of the conductive particles is such that the conductive particles are scattered on the steel sheet having a smooth surface at room temperature, and one conductive particle is selected from the conductive particles dispersed. Then, a smooth end surface of a 50 μm diameter cylinder made of diamond made of a micro compression tester (for example, PCT-200 type: manufactured by Shimadzu Corporation) is pressed against the selected one of the conductive particles to be compressed. The conductive particles. Then, according to the relationship shown in Fig. 2, the load value F (kgf) is calculated from the compression shift S (mm) at 30% compression of the conductive particles.

Then, by calculating the load value F (kgf) and the compression shift S (mm), the compression hardness K value at the time of 30% compression is calculated using the formula (1).

(Comparative Example 1 to Comparative Example 3)

In Comparative Example 1 to Comparative Example 3, an anisotropic property was produced in the same manner as in the Example except that the compressive hardness at the time of 30% compression of the resin core-plated Ni particles was changed as shown in Table 1. Conductive film.

<Crack generation test>

In the crack generation test, a flexible film having a Young's modulus of the Young's modulus shown in Table 1 or polyethylene terephthalate (PET) was used. Wiring was formed on the flexible film with a size of 20 mm × 40 mm × total thickness of 50.6 μm, and PI/AI/ITO = 50 μm / 0.5 μm / 0.1 μm and a pitch of 50 μm.

Next, the anisotropic conductive film placed on the flexible film on which the wiring is formed is placed on the IC wafer in such a manner that the IC wafer is placed opposite to the wiring via the anisotropic conductive film. On the conductive film. Then, the upper surface of the IC wafer was heated and pressurized by a pressing head at a temperature of 200 ° C and a pressure of 600 kgf / cm ² to be connected thereto, thereby producing a bonded structure.

Moreover, the occurrence of cracks in the wiring was confirmed by visual observation. The rate of occurrence of cracks indicates the ratio of cracks generated in 100 wirings. The crack generation rate is shown in Tables 1 and 2.

<Test of on-resistance value>

In the test of the on-resistance value, the flexible film was connected to the flexible wiring board in the same manner as the crack generation test, and the connection structure was produced, and the on-resistance was measured. In the flexible wiring board, the element for measurement characteristic measurement for conducting the measurement wiring was formed with a size of 20 mm × 40 mm × 50.5 μm and PI / AI / ITO = 50 μm / 0.5 μm / 0.1 μm and a pitch of 50 μm. The on-resistance value after leaving for 125 hours (after aging) in an environment of 85 ° C / 85% RH was evaluated. The on-resistance value was measured by using a digital-multimeter (trade name: digital-multimeter 7561, manufactured by Yokogawa Electric Co., Ltd.), and the on-resistance value at the time of flowing a current of 1 mA was measured by a four-terminal method. When the on-resistance value after aging is 10 Ω or less, the resistance is set to be low. The measurement results of the on-resistance values are shown in Tables 1 and 2.

As is clear from the results shown in Tables 1 and 2, in Examples 1 to 5, cracks did not occur in the wiring, and the occurrence rate of cracks was lower than that of Comparative Examples 2 and 3, and generation of cracks was suppressed. Therefore, it is understood from Examples 1 to 5 that the compression hardness at the time of 30% compression deformation of the conductive particles in the anisotropic conductive film is in the range of 150 to 400 Kgf/mm ² , thereby suppressing the occurrence of cracks in the wiring.

Further, in Examples 1 to 5, the on-resistance value was lower than that of Comparative Example 1, and the on-resistance was lowered. Therefore, it is understood from Examples 1 to 5 that the crack hardness of the wiring can be suppressed by suppressing the compression hardness at 30% of the conductive particles in the anisotropic conductive film from 150 to 400 Kgf/mm ² , and The on-resistance value can be reduced. In the examples, in Example 2, cracks in the wiring were not generated, and the on-resistance value was lowered.

With respect to these examples, the compression hardness at the time of 30% compression deformation of the conductive particles in Comparative Example 1 was 100 Kgf/mm ² , and the hardness was low. Therefore, cracks in the wiring were not generated, but the conductive particles were immersed in the wiring. Insufficient to obtain a lower on-resistance value.

In Comparative Examples 2 and 3, when the 30% compression deformation of the conductive particles was 500 Kgf/mm ² and 720 Kgf/mm ² , the hardness was high and hard, and thus the electric resistance was low, but wiring cracks were generated. Since Comparative Example 3 is harder than Comparative Example 2, cracks in the wiring are more likely to occur.

Claims (16)

A method for manufacturing a connection structure is characterized in that an anisotropic conductive connection layer is interposed between a terminal of a flexible display and a terminal of an electronic component, and the flexible display is connected and electrically connected to the electronic component, wherein The step of mounting: mounting the electronic component on the flexible display such that the terminal of the electronic component faces the terminal provided on the flexible display via the anisotropic conductive connection layer And a connecting step of pressing the electronic component to the flexible display, and connecting the terminal disposed on the flexible display to the terminal of the electronic component through the anisotropic conductive connecting layer, and connecting through the opposite direction The conductive particles in the conductive connection layer conduct the terminals; the compression hardness of the conductive particles at 30% compression deformation is 150 to 400 Kgf/mm ² ; and the average particle density of the conductive particles is 1000 to 50000 / Mm ² , but does not contain 1000~5000/mm ² . The method for producing a bonded structure according to the first aspect of the invention, wherein the conductive particles have an average particle density of 3,000 to 30,000/mm ² . The method for producing a bonded structure according to claim 1 or 2, wherein the flexible film used for the substrate of the flexible display has a Young's modulus of 2 to 10 GPa. The method for producing a bonded structure according to claim 1 or 2, wherein the compressive hardness at 30% compression deformation of the conductive particles is 150 to 350 Kgf/mm ² . The method for producing a bonded structure according to claim 1 or 2, wherein the flexible film used for the substrate of the flexible display is polyimide or polyethylene terephthalate. A connection method is characterized in that a terminal provided on a flexible display is connected to a terminal of an electronic component by an anisotropic conductive connection layer, and the method has the following steps: a mounting step: connecting the anisotropic conductive connection The layer mounts the electronic component on the flexible display such that the terminal of the electronic component faces the terminal disposed on the flexible display; and the connecting step: pressurizing the electronic component to the flexible display And connecting the terminal disposed on the flexible display to the terminal of the electronic component by using the anisotropic conductive connection layer, and conducting the terminals through the conductive particles in the anisotropic conductive connection layer; the conductivity The compression hardness at 30% compression deformation of the particles is 150 to 400 Kgf/mm ² ; the average particle density of the conductive particles is 1000 to 50,000 / mm ² , but does not include 1000 to 5000 / mm ² . The joining method of claim 6, wherein the conductive particles have an average particle density of 3,000 to 30,000/mm ² . The joining method of claim 6 or 7, wherein the flexible film used for the substrate of the flexible display has a Young's modulus of 2 to 10 GPa. The joining method of claim 6 or 7, wherein the compressive hardness of the conductive particles at 30% compression deformation is 150 to 350 Kgf/mm ² . The joining method of claim 6 or 7, wherein the flexible film used in the flexible display is polyimine or polyethylene terephthalate. An anisotropic conductive film is connected to a terminal of a flexible display and a terminal of an electronic component, and has a compression hardness of 150 to 400 Kgf / mm ² when the insulating adhesive contains 30% compression deformation. Further, the average particle density is 1000 to 50,000/mm ² of conductive particles, but does not include 1000 to 5000/mm ² . The anisotropic conductive film of claim 11, wherein the conductive particles have an average particle density of 3,000 to 30,000/mm ² . The anisotropic conductive film of claim 11 or 12, wherein the conductive particles have a compression hardness of 150 to 350 Kgf/mm ² at 30% compression deformation. The anisotropic conductive film of claim 11 or 12, wherein the conductive particles are particles obtained by metal plating a resin. A connection structure is characterized in that an anisotropic conductive connection layer is interposed between a terminal of a flexible display and a terminal of an electronic component, and the flexible display is connected and electrically connected to the electronic component, wherein The compressive hardness at 30% compression deformation of the conductive particles in the anisotropic conductive connection layer is 150 to 400 Kgf/mm ² ; and the average particle density is 1000 to 50000 / mm ² , but does not include 1000 to 5000 /mm ² . The bonded structure according to claim 15, wherein the conductive particles have an average particle density of 3,000 to 30,000/mm ² .