JP7027390B2 - Connection body and manufacturing method of connection body - Google Patents

Description

The present invention relates to a method for manufacturing a connector and a connector in which an electronic component and a circuit board are connected, and in particular, the connector and a connector in which the electronic component is connected to the circuit board via an adhesive containing conductive particles. Regarding the manufacturing method of.

Conventionally, a liquid crystal display device or an organic EL panel has been used as various display means such as a television, a PC monitor, a mobile phone, a smart phone, a portable game machine, a tablet terminal, a wearable terminal, or an in-vehicle monitor. In recent years, in such a display device, a so-called COG (chip on glass) in which a drive IC is directly mounted on a glass substrate of a display panel has been adopted from the viewpoint of fine pitch, light weight and thinness.

For example, in a liquid crystal display panel in which a COG mounting method is adopted, as shown in FIGS. 12A and 12B, a transparent substrate 101 made of a glass substrate or the like has a transparent electrode 102 made of ITO (indium tin oxide) or the like. A plurality of them are formed, and electronic components such as a liquid crystal drive IC 103 are connected on these transparent electrodes 102. In the liquid crystal drive IC 103, a plurality of electrode terminals 104 corresponding to the transparent electrodes 102 are formed on the mounting surface, and the electrode terminals 104 are thermocompression bonded onto the transparent substrate 101 via the anisotropic conductive film 105. And the transparent electrode 102 are connected.

The anisotropic conductive film 105 is formed by mixing conductive particles with a binder resin to form a film. By heat-pressing between two conductors, the conductive particles take electrical conduction between the conductors. The binder resin maintains the mechanical connection between the conductors. As the adhesive constituting the anisotropic conductive film 105, a highly reliable thermosetting binder resin is usually used, but a photocurable binder resin or a photoheat-combined type binder resin may be used.

When connecting the liquid crystal drive IC 103 to the transparent electrode 102 via such an anisotropic conductive film 105, first, the anisotropic conductive film 105 is placed on the transparent electrode 102 of the transparent substrate 101 by a temporary crimping means (not shown). Temporarily paste. Subsequently, the liquid crystal drive IC 103 is mounted on the transparent substrate 101 via the anisotropic conductive film 105 to form a temporary connector, and then the liquid crystal drive IC 103 is anisotropic by a thermocompression bonding means such as a thermocompression bonding head 106. It is heated and pressed toward the transparent electrode 102 side together with the conductive film 105. By heating by the thermocompression bonding head 106, the anisotropic conductive film 105 undergoes a thermosetting reaction, whereby the liquid crystal drive IC 103 is adhered onto the transparent electrode 102.

Japanese Patent No. 4789738 Japanese Unexamined Patent Publication No. 2004-214374 Japanese Unexamined Patent Publication No. 2005-203758

With the recent miniaturization and higher definition of liquid crystal display devices and other electronic devices, the wiring pitch of circuit boards and the fine pitch of electrode terminals of electronic components have become finer, and the electrode terminals have become finer using anisotropic conductive films. When electronic components such as IC chips are COG-connected on a pitched circuit board, the conductive particles are densely packed to ensure conduction even between the narrowed electrode terminals. Need to be filled.

However, as shown in FIG. 13, when the conductive particles 107 are packed at a high density while the wiring pitch of the circuit board and the fine pitch of the electrode terminals of the electronic components are increasing, the conductive particles dispersed between the electrode terminals 104 are dispersed. The occurrence rate of short circuit between terminals increases due to the continuation of 107.

In general, the electrodes formed on the circuit board are formed to be as thin as several tens of nm to several μm by printing or the like, so that a short circuit between the electrodes on the circuit board side does not matter.

Therefore, the present invention secures continuity between the electronic component and the circuit board and prevents a short circuit between the electrode terminals of the electronic component even if the wiring pitch of the circuit board or the electrode terminal of the electronic component is made fine pitch. It is an object of the present invention to provide a connecting body which can be manufactured and a method for manufacturing the connecting body.

In order to solve the above-mentioned problems, the connection body according to the present invention is a connection body in which electronic components are connected via an anisotropic conductive adhesive on a circuit board, and the anisotropic conductive adhesive is a binder. Conductive particles are arranged on the resin, and the connection electrode formed on the electronic component and the substrate electrode formed on the circuit board are displaced in the arrangement direction of the connection electrode and the substrate electrode, and the connection electrode and the substrate electrode are arranged. The minimum distance in the arrangement direction of the substrate electrodes is less than four times the particle diameter of the conductive particles, and the distance between the particles of the conductive particles in the space between the connection electrodes formed on the electronic component is the above . It is longer than the interparticle distance between the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode, and is between the substrate electrode formed on the circuit board and the connection electrode. The extrinsic line in the longitudinal direction of the substrate electrode of the conductive particles captured in the above penetrates the conductive particles captured adjacent to the longitudinal direction.

Further, in the method for manufacturing a connector according to the present invention, an electronic component is mounted on a circuit board via an adhesive containing conductive particles, and the electronic component is pressed against the circuit board and described above. In the method for manufacturing a connector for connecting the electronic component to the circuit board by curing the adhesive, the adhesive is a connection electrode formed on the electronic component by arranging conductive particles on a binder resin. And the substrate electrode formed on the circuit board are displaced in the arrangement direction of the connection electrode and the substrate electrode, and the minimum distance in the arrangement direction of the connection electrode and the substrate electrode is the particle diameter of the conductive particles. It is less than four times, and the interparticle distance between the conductive particles in the space between the connection electrodes is captured between the substrate electrode formed on the circuit board and the connection electrode formed on the electronic component. The extrinsic line in the longitudinal direction of the substrate electrode of the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode, which is longer than the interparticle distance between the conductive particles. Penetrates the conductive particles captured adjacently in the longitudinal direction.

According to the present invention, the inter-particle distance between the conductive particles in the inter-terminal space between the adjacent electrode terminals is longer than the inter-particle distance between the conductive particles captured between the connection electrode and the substrate electrode. Therefore, it is possible to prevent a short circuit between terminals due to a series of conductive particles in the space between terminals of the connection electrode having a fine pitch.

FIG. 1 is a cross-sectional view of a liquid crystal display panel shown as an example of a connector. FIG. 2 is a cross-sectional view showing a connection process between the liquid crystal drive IC and the transparent substrate. FIG. 3 is a plan view showing the electrode terminals (bumps) of the liquid crystal drive IC and the space between the terminals. FIG. 4 is a cross-sectional view showing the minimum distance D in the arrangement direction of the electrode terminals and the terminal portions in the liquid crystal drive IC and the transparent substrate. FIG. 5 is a cross-sectional view showing an anisotropic conductive film. FIG. 6 is a plan view showing an anisotropic conductive film in which conductive particles are regularly arranged in a grid pattern. FIG. 7 is a graph showing the distribution of the number of captured particles of the electrode terminals in the anisotropic conductive film in which the conductive particles are regularly arranged and the anisotropic conductive film in which the conductive particles are randomly dispersed. FIG. 8A is a plan view showing an anisotropic conductive film in which the conductive particles are sparse in the longitudinal direction and densely arranged in the width direction, and FIG. 8B is a plan view in which the conductive particles are arranged in the longitudinal direction. It is a top view which shows the anisotropic conductive film which is densely arranged loosely in the width direction. FIG. 9 shows a state in which an anisotropic conductive film in which conductive particles are arranged in an inclined manner with respect to the longitudinal direction and the width direction of the film is arranged on the terminal portion along the arrangement direction of the terminal portion in the longitudinal direction of the film. It is a plan view which shows. In FIG. 10, another anisotropic conductive film in which conductive particles are arranged so as to be inclined with respect to the longitudinal direction and the width direction of the film is arranged on the terminal portion in the longitudinal direction of the film along the arrangement direction of the terminal portion. It is a top view which shows the state. In FIG. 11, another anisotropic conductive film in which conductive particles are arranged so as to be inclined with respect to the longitudinal direction and the width direction of the film is arranged on the terminal portion in the longitudinal direction of the film along the arrangement direction of the terminal portion. It is a top view which shows the state. FIG. 12 is a cross-sectional view showing a step of connecting an IC chip to a transparent substrate of a liquid crystal display panel, where (A) a step before connection and (B) show a connection step. FIG. 13 is a cross-sectional view showing a connection state between the conventional transparent substrate and the IC chip.

Hereinafter, the connecting body to which the present invention is applied and the manufacturing method of the connecting body will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention. In addition, the drawings are schematic, and the ratio of each dimension may differ from the actual one. Specific dimensions, etc. should be determined in consideration of the following explanation. In addition, it goes without saying that parts having different dimensional relationships and ratios are included between the drawings.

[Liquid crystal display panel]
Hereinafter, as a connector to which the present invention is applied, a liquid crystal display panel in which an IC chip for driving a liquid crystal as an electronic component is mounted on a glass substrate will be described as an example. As shown in FIG. 1, in the liquid crystal display panel 10, two transparent substrates 11 and 12 made of a glass substrate or the like are arranged to face each other, and the transparent substrates 11 and 12 are bonded to each other by a frame-shaped seal 13. .. The liquid crystal display panel 10 is formed by enclosing the liquid crystal 14 in the space surrounded by the transparent substrates 11 and 12.

The transparent substrates 11 and 12 are formed on both inner surfaces facing each other so that a pair of striped transparent electrodes 16 and 17 made of ITO (indium tin oxide) or the like intersect each other. The two transparent electrodes 16 and 17 are configured to have pixels as the minimum unit of the liquid crystal display by the intersections of the two transparent electrodes 16 and 17.

Of the two transparent substrates 11 and 12, one of the transparent substrates 12 is formed to have a larger plane dimension than the other transparent substrate 11, and the edge portion 12a of the large transparent substrate 12 is used as an electronic component. A COG mounting unit 20 on which the liquid crystal drive IC 18 is mounted is provided. The COG mounting portion 20 is formed with a terminal portion 17a of the transparent electrode 17 and a substrate-side alignment mark 21 superimposed on the IC-side alignment mark 22 provided on the liquid crystal display driving IC 18.

The liquid crystal drive IC 18 can display a predetermined liquid crystal display by partially changing the orientation of the liquid crystal by selectively applying the liquid crystal drive voltage to the pixels. Further, as shown in FIG. 2, in the liquid crystal drive IC 18, a plurality of electrode terminals 19 (bumps) conductively connected to the terminal portion 17a of the transparent electrode 17 are formed on the mounting surface 18a on the transparent substrate 12. .. As the electrode terminal 19, for example, a copper bump, a gold bump, or a copper bump plated with gold is preferably used.

[Electrode terminal]
In the liquid crystal drive IC 18, for example, as shown in FIG. 3, electrode terminals 19 (input bumps) are arranged in a row along one side edge of the mounting surface 18a, and the other side edge facing one side edge is arranged. Electrode terminals 19 (output bumps) are arranged in a plurality of rows in a staggered manner along the line. The electrode terminals 19 and the terminal portions 17a provided on the COG mounting portion 20 of the transparent substrate 12 are formed in the same number and at the same pitch, respectively, and the transparent substrate 12 and the liquid crystal drive IC 18 are aligned and connected to each other. By doing so, it is connected.

With the recent miniaturization and higher functionality of liquid crystal displays and other electronic devices, electronic components such as the liquid crystal drive IC 18 are also required to be smaller and lower in height, and the height of the electrode terminal 19 is also lowered. (For example, 6 to 15 μm).

Further, as described above, with the recent miniaturization and higher definition of liquid crystal display devices and other electronic devices, the wiring pitch of circuit boards and the fine pitch of electrode terminals of electronic components are also becoming finer. For example, in the liquid crystal drive IC 18, the size of the connection surface connected to the terminal portion 17a of the electrode terminal 19 is 8 to 60 μm in width, 400 μm or less in length, and the lower limit is the same distance as the width (8 to 60 μm) or conductive. It is said to be less than 7 times the particle size. Further, the minimum distance between the electrode terminals 19 is also set to, for example, 8 to 30 μm according to the width of the electrode terminals 19. Further, for example, the minimum distance D in the arrangement direction of the electrode terminal 19 and the terminal portion 17a shown in FIG. 4 (this distance may be deviated in the arrangement direction within a range where anisotropic connection is possible) is the conductive particle. It can be less than 4 times the diameter.

Further, as will be described later, the liquid crystal drive IC 18 is mounted on the COG mounting portion 20 of the transparent substrate 12, so that the fluidity of the binder resin of the anisotropic conductive film 1 is on the electrode terminal 19 and the adjacent electrodes. Unlike the space 23 between the terminals 19, the fluidity of the binder resin in the space 23 between the terminals is higher and easier to flow. Due to this fluidity, the liquid crystal display panel 10 is the distance between the conductive particles 4 and the closest particles on the electrode terminal 19 connected to the terminal portion 17a (hereinafter, also referred to as “inter-particle distance”). The interparticle distance of the conductive particles 4 in the inter-terminal space 23 is longer than that of the above.

Further, the liquid crystal drive IC 18 has an IC-side alignment mark 22 for aligning with the transparent substrate 12 by superimposing the liquid crystal drive IC 18 on the mounting surface 18a with the substrate-side alignment mark 21. Since the wiring pitch of the transparent electrode 17 of the transparent substrate 12 and the fine pitch of the electrode terminal 19 of the liquid crystal drive IC 18 are becoming finer, high-precision alignment adjustment is required between the liquid crystal drive IC 18 and the transparent substrate 12. Has been done.

As the substrate-side alignment mark 21 and the IC-side alignment mark 22, various marks that can be combined to align the transparent substrate 12 and the liquid crystal drive IC 18 can be used.

A liquid crystal display driving IC 18 is connected to the terminal portion 17a of the transparent electrode 17 formed on the COG mounting portion 20 by using an anisotropic conductive film 1 as a circuit connecting adhesive. The anisotropic conductive film 1 contains the conductive particles 4, and the electrode terminal 19 of the liquid crystal drive IC 18 and the terminal portion 17a of the transparent electrode 17 formed on the edge portion 12a of the transparent substrate 12 are made conductive. It is electrically connected via the particles 4. The anisotropic conductive film 1 is thermocompression-bonded by the thermocompression-bonding head 33, so that the binder resin is fluidized and the conductive particles 4 are crushed between the terminal portion 17a and the electrode terminal 19 of the liquid crystal drive IC 18. , The binder resin is cured in this state. As a result, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 and the liquid crystal drive IC 18.

Further, an alignment film 24 subjected to a predetermined rubbing treatment is formed on both the transparent electrodes 16 and 17, and the initial orientation of the liquid crystal molecules is regulated by the alignment film 24. Further, a pair of polarizing plates 25 and 26 are arranged on the outside of both transparent substrates 11 and 12, and the light transmitted from a light source (not shown) such as a backlight is transmitted by these polarizing plates 25 and 26. The vibration direction is regulated.

[Animate conductive film]
Next, the anisotropic conductive film 1 will be described. As shown in FIG. 5, the anisotropic conductive film (ACF) 1 usually has a binder resin layer (adhesive layer) 3 containing conductive particles 4 on a release film 2 as a base material. It was formed. The anisotropic conductive film 1 is a thermosetting type or a photocurable adhesive such as ultraviolet rays, and is attached on a transparent electrode 17 formed on a transparent substrate 12 of a liquid crystal display panel 10 and is a liquid crystal drive IC18. Is mounted and fluidized by being thermally pressurized by the thermal crimping head 33, and the conductive particles 4 are crushed between the terminal portion 17a of the transparent electrode 17 facing each other and the electrode terminal 19 of the liquid crystal drive IC 18. The conductive particles are cured in a crushed state by heating or irradiation with ultraviolet rays. Thereby, the anisotropic conductive film 1 can connect the transparent substrate 12 and the liquid crystal drive IC 18 and make them conductive.

Further, in the anisotropic conductive film 1, the conductive particles 4 are regularly arranged in a predetermined pattern on a normal binder resin layer 3 containing a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent and the like. It is arranged in.

The release film 2 that supports the binder resin layer 3 is, for example, a release agent such as silicone applied to PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), PTFE (Polytetrafluoroethylene) and the like. It is coated to prevent the anisotropic conductive film 1 from drying and to maintain the shape of the anisotropic conductive film 1.

As the film-forming resin contained in the binder resin layer 3, a resin having an average molecular weight of about 10,000 to 80,000 is preferable. Examples of the film-forming resin include various resins such as epoxy resin, modified epoxy resin, urethane resin, and phenoxy resin. Of these, phenoxy resin is particularly preferable from the viewpoint of film formation state, connection reliability and the like.

The thermosetting resin is not particularly limited, and examples thereof include commercially available epoxy resins and acrylic resins.

The epoxy resin is not particularly limited, but for example, a naphthalene type epoxy resin, a biphenyl type epoxy resin, a phenol novolac type epoxy resin, a bisphenol type epoxy resin, a stillben type epoxy resin, a triphenol methane type epoxy resin, and a phenol aralkyl type epoxy resin. , Naftor 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 an acrylic compound, a liquid acrylate, or the like can be appropriately selected depending on the intended purpose. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethyloltricyclodecanediacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-. 1,3-Diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclo Examples thereof include decanyl acrylate, tris (acryloxyethyl) isocyanurate, urethane acrylate, and epoxy acrylate. In addition, what made acrylate into methacrylate can also be used. These may be used alone or in combination of two or more.

The latent curing agent is not particularly limited, and examples thereof include various curing agents such as a heat curing type and a UV curing type. The latent curing agent does not normally react, but is activated by various triggers selected according to the application such as heat, light, and pressurization to initiate the reaction. The method of activating the heat-active latent curing agent is a method of generating active species (cations, anions, radicals) by a dissociation reaction by heating, and a method of stably dispersing in an epoxy resin near room temperature and epoxy at a high temperature. There are a method of incompatible / dissolving with a resin to start a curing reaction, a method of eluting a molecular sieve-encapsulated type curing agent at a high temperature to start a curing reaction, a method of eluting / curing with microcapsules, and the like. Thermally active latent curing agents include imidazole type, hydrazide type, boron trifluoride-amine complex, sulfonium salt, amineimide, polyamine salt, dicyandiamide and the like, and modified products thereof. The above mixture may be used. Of these, a microcapsule type imidazole-based latent curing agent is preferable.

The silane coupling agent is not particularly limited, and examples thereof include epoxy-based, amino-based, mercapto-sulfide-based, and ureido-based. By adding the silane coupling agent, the adhesiveness at the interface between the organic material and the inorganic material is improved.

[Conductive particles]
Examples of the conductive particles 4 include any known conductive particles used in the anisotropic conductive film 1. Examples of the conductive particles 4 include particles of various metals such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, and gold, particles of metal alloys, metal oxides, carbon, graphite, glass, and ceramics. Examples thereof include those in which the surface of particles such as plastic is coated with metal, and those in which the surface of these particles is further coated with an insulating thin film. When the surface of the resin particles is coated with a metal, the resin particles include, for example, epoxy resin, phenol resin, acrylic resin, acrylonitrile-styrene (AS) resin, benzoguanamine resin, divinylbenzene resin, styrene resin and the like. Particles can be mentioned. The size of the conductive particles 4 is preferably 1 to 10 μm, but the present invention is not limited thereto.

[Regular arrangement of conductive particles]
In the anisotropic conductive film 1, the conductive particles 4 are regularly arranged in a predetermined arrangement pattern in a plan view, and some are arranged in a grid pattern and evenly, for example, as shown in FIG. Due to the regular arrangement in the plan view, the anisotropic conductive film 1 is finer between the adjacent electrode terminals 19 of the liquid crystal drive IC 18 than in the case where the conductive particles 4 are randomly dispersed. Even if the area between the terminals is pitched and the area between the terminals is narrowed, and even if the conductive particles 4 are packed at high density, short-circuiting between the electrode terminals 19 due to the aggregates of the conductive particles 4 is prevented in the connection process of the liquid crystal drive IC 18. can do.

Further, in the anisotropic conductive film 1, the conductive particles 4 are regularly arranged, so that even when the binder resin layer 3 is filled with high density, the occurrence of sparse and dense due to the aggregation of the conductive particles 4 is prevented. Has been done. Therefore, according to the anisotropic conductive film 1, the conductive particles 4 can be captured even in the terminal portion 17a and the electrode terminals 19 having a fine pitch. The uniform arrangement pattern of the conductive particles 4 can be arbitrarily set. The connection process of the liquid crystal drive IC 18 will be described in detail later.

In such an anisotropic conductive film 1, for example, a pressure-sensitive adhesive is applied onto a stretchable sheet, conductive particles 4 are arranged in a single layer on the adhesive, and then the sheet is stretched at a desired stretching ratio. Method, a method of transferring the conductive particles 4 to the binder resin layer 3 supported by the release film 2 after arranging the conductive particles 4 in a predetermined arrangement pattern on the substrate, or a method of transferring the conductive particles 4 to the binder resin layer 3 supported by the release film 2. It can be manufactured by a method of supplying the conductive particles 4 via an arrangement plate provided with openings corresponding to the arrangement pattern on the resin layer 3.

[Particle number density]
Here, since the wiring pitch of the transparent electrode 17 of the transparent substrate 12 and the fine pitch of the electrode terminal 19 of the liquid crystal drive IC 18 are becoming finer, when the liquid crystal drive IC 18 is COG-connected on the transparent substrate 12, the fine pitch is increased. In order to ensure conduction by sandwiching the conductive particles between the electrode terminal 19 and the terminal portion 17a, the anisotropic conductive film 1 has the conductive particles 4 arranged at a high density. ..

Specifically, in the anisotropic conductive film 1, the conductive particles 4 are arranged at a number density of 5000 to 60,000 particles / mm ² . If the particle number density is less than 5000 particles / mm ² , the number of particles captured between the fine-pitched electrode terminal 19 and the terminal portion 17a decreases, and the conduction resistance increases. Further, if the particle number density is more than 60,000 particles / mm ² , the conductive particles 4 in the narrowed space between the terminals 19 between the electrode terminals 19 will be connected, and there is a possibility that the adjacent electrode terminals 19 will be short-circuited. be. It should be noted that these are examples, and the particle number density is arbitrarily adjusted from the size of the conductive particles 4, and the present invention is not limited thereto.

The shape of the anisotropic conductive film 1 is not particularly limited, but for example, as shown in FIG. 5, a long tape shape that can be wound around the take-up reel 6 is used, and the length is cut by a predetermined length. can do.

Further, in the above-described embodiment, as the anisotropic conductive film 1, an adhesive film obtained by molding a thermosetting resin composition in which conductive particles 4 are regularly arranged on a binder resin layer 3 into a film shape has been described as an example. The adhesive according to the present invention is not limited to this, and for example, an insulating adhesive layer made of only the binder resin 3 and a conductive particle-containing layer made of the binder resin 3 in which the conductive particles 4 are regularly arranged are laminated. It can be configured. Further, in the anisotropic conductive film 1, if the conductive particles 4 are regularly arranged in a plan view, they are arranged in a single layer as shown in FIG. 5, and the conductive particles 4 are arranged over a plurality of binder resin layers 3. Are arranged and may be regularly arranged in a plan view. Further, the anisotropic conductive film 1 may be singly dispersed at a predetermined distance in at least one layer having a multilayer structure.

[Connection process]
Next, a connection step of connecting the liquid crystal drive IC 18 to the transparent substrate 12 will be described. First, the anisotropic conductive film 1 is temporarily attached onto the COG mounting portion 20 on which the terminal portion 17a of the transparent substrate 12 is formed. Next, the transparent substrate 12 is placed on the stage of the connecting device, and the liquid crystal drive IC 18 is arranged on the mounting portion of the transparent substrate 12 via the anisotropic conductive film 1.

Next, the binder resin layer 3 is heat-pressed from the liquid crystal drive IC 18 at a predetermined pressure and time by a thermocompression bonding head 33 heated to a predetermined temperature. As a result, the binder resin layer 3 of the anisotropic conductive film 1 exhibits fluidity, flows out from between the mounting surface 18a of the liquid crystal drive IC 18 and the COG mounting portion 20 of the transparent substrate 12, and is in the binder resin layer 3. The conductive particles 4 are sandwiched between the electrode terminal 19 of the liquid crystal drive IC 18 and the terminal portion 17a of the transparent substrate 12 and crushed.

As a result, the conductive particles 4 are electrically connected by sandwiching the conductive particles 4 between the electrode terminal 19 and the terminal portion 17a, and the binder resin heated by the thermocompression bonding head 33 is cured in this state. As a result, it is possible to manufacture the liquid crystal display panel 10 in which the conductivity is ensured between the electrode terminal 19 of the liquid crystal driving IC 18 and the terminal portion 17a formed on the transparent substrate 12.

The conductive particles 4 that are not between the electrode terminal 19 and the terminal portion 17a are dispersed in the binder resin in the space between the terminals 23 between the adjacent electrode terminals 19, and maintain an electrically insulated state. As a result, electrical conduction is achieved only between the electrode terminal 19 of the liquid crystal drive IC 18 and the terminal portion 17a of the transparent substrate 12. By using a radical polymerization reaction system, which is a fast-curing type, as the binder resin, the binder resin can be quickly cured even with a short heating time. Further, the anisotropic conductive film 1 is not limited to the thermosetting type, and a photocuring type or a photothermal combined type adhesive may be used as long as it is pressure-connected.

[Distance between conductive particles]
Here, in the present invention, the interparticle distance between the conductive particles 4 in the inter-terminal space 23 between the adjacent electrode terminals 19 is the distance between the conductive particles 4 captured between the electrode terminal 19 and the terminal portion 17a. Longer than the interparticle distance of. Therefore, the liquid crystal display panel 10 can prevent a short circuit between terminals due to a series of conductive particles 4 in the space 23 between terminals of the finely pitched electrode terminals 19.

That is, in the present invention, the conductive particles 4 of the anisotropic conductive film 1 are regularly arranged. Further, at the time of thermal pressurization by the thermocompression bonding head 33, the liquid crystal drive IC 18 has higher fluidity of the binder resin in the space 23 between the terminals than on the electrode terminals 19, and is more likely to flow. Further, the conductive particles 4 captured between the electrode terminal 19 and the terminal portion 17a are less affected by the flow of the binder resin.

On the other hand, the conductive particles 4 in the space between terminals 23 are not sandwiched between the electrode terminals 19 and the terminal portions 17a, and are relatively greatly affected by the binder resin that flows due to the thermal pressurization by the thermocompression bonding head 33. Therefore, the distance between the conductive particles 4 in the space between terminals 23 is relatively large. Therefore, the liquid crystal display panel 10 can surely capture the conductive particles 4 between the electrode terminal 19 and the terminal portion 17a to secure the conductivity, and the space between the terminals between the adjacent electrode terminals 19 can be ensured. In 23, since the distance between particles is maintained, a short circuit between the electrode terminals 19 can be prevented.

Further, as described above, the number density of the conductive particles is preferably 5000 to 60,000 particles / mm ² . By having the number density, the liquid crystal display panel 10 prevents a short circuit between terminals due to the continuation of the conductive particles 4 in the narrowed space between terminals 23, and at the same time, the fine pitched electrode terminals 19 and terminals. Conductive particles 4 can be reliably captured between the portions 17a and the conductivity can be improved.

FIG. 7 shows an anisotropic conductive film 1 (number density: 28,000 / mm ² ) in which the conductive particles 4 are regularly arranged and an anisotropic conductive film (number density) in which the conductive particles are randomly dispersed. : 60,000 pieces / mm ² ) is a graph comparing the distribution of the number of conductive particles captured by one electrode terminal 19 in the anisotropically conductively connected connectors. The size of the electrode terminals 19 is 14 μm × 50 μm (= 700 μm ² ), and the distance between the electrode terminals 19 is 14 μm. The binder and connection conditions of the anisotropic conductive film 1 are the same as those in the following examples and comparative examples.

As shown in FIG. 7, it can be seen that the capture reliability is improved in the connection body manufactured by using the anisotropic conductive film 1.

[Sparsely dense arrangement in the longitudinal direction of the film]
Further, as shown in FIG. 8A, the anisotropic conductive film 1 is formed in a film shape having the arrangement direction of the terminal portion 17a and the electrode terminals 19 in the longitudinal direction, and the conductive particles 4 are formed in the longitudinal direction. It may be sparse and densely arranged in the width direction.

The anisotropic conductive film 1 is attached in the longitudinal direction along the arrangement direction of the terminal portion 17a and the electrode terminals 19. Therefore, in the anisotropic conductive film 1, the conductive particles 4 are sparsely arranged along the arrangement direction of the terminal portion 17a and the electrode terminal 19 by being bonded to the COG mounting portion 20, and the terminal portion 17a and the electrode terminal 19 are arranged. It is densely arranged in the length direction.

In such an anisotropic conductive film 1, the conductive particles 4 are relatively sparsely arranged in the arrangement direction of the terminal portion 17a and the electrode terminals 19, so that the anisotropic conductive film 1 extends between the adjacent electrode terminals 19 in the terminal-to-terminal space 23. Since the number of the conductive particles 4 is reduced and the distance between the particles is widened, it is possible to further prevent a short circuit between the electrode terminals 19.

Further, in the anisotropic conductive film 1, since the conductive particles 4 are relatively densely arranged in the width direction, the particle capture rate of the conductive particles 4 between the terminal portion 17a and the electrode terminal 19 is high. Go up. Therefore, the continuity with the liquid crystal drive IC 18 is not impaired.

As shown in FIG. 8B, the anisotropic conductive film 1 is formed in a film shape having the arrangement direction of the terminal portion 17a and the electrode terminals 19 in the longitudinal direction, and the conductive particles 4 are formed in the longitudinal direction. It may be densely and sparsely arranged in the width direction.

Also in this case, the conductive particles 4 in the space between terminals 23 are greatly affected by the binder resin that flows due to the thermal pressurization by the thermocompression bonding head 33, and the distance between the particles becomes relatively large. Therefore, the liquid crystal display panel 10 can prevent a short circuit between the electrode terminals 19.

Further, in the liquid crystal display panel 10, since the conductive particles 4 are relatively densely arranged in the length direction of the film, the conductive particles 4 are reliably captured between the terminal portion 17a and the electrode terminals 19. This can be done, and the continuity with the liquid crystal drive IC 18 is not impaired.

[High density filling array]
Further, as shown in FIGS. 9 to 11, the anisotropic conductive film 1 is arranged by inclining the conductive particles 4 with respect to the width direction Lt orthogonal to the longitudinal direction Lf of the film, and is arranged in the longitudinal direction of the film. By arranging Lf parallel to the arrangement direction of the terminal portions 17a and the width direction Lt of the film parallel to the longitudinal direction of the terminal portions 17a, the anisotropic conductive film 1 is conductive in the direction orthogonal to the longitudinal direction Lf. The extrinsic line (two-point chain line) of the particle P may penetrate the conductive particles Pc and Pe adjacent to the conductive particle P.

As a result, in the plan view in which the anisotropic conductive film 1 is superposed on the terminal portion 17a of the transparent electrode 17, the interparticle distance between the adjacent conductive particles 4 in the width direction (longitudinal direction Lf of the film) of the terminal portion 17a is close. Therefore, it is possible to improve the capture rate of the conductive particles 4 in the connection surface of the terminal portion 17a having a fine pitch. Therefore, the anisotropic conductive film 1 is sandwiched between the opposite electrode terminals 19 at the time of the anisotropic conductive connection and pushed into the terminal portion 17a, and the conductive particles are made conductive between the electrode terminals 19 and the terminal portions 17a. It is possible to prevent the number of Ps from becoming insufficient.

In the anisotropic conductive film 1 shown in FIGS. 9 to 11, the conductive particles are inclined in the second arrangement direction L2 in the film width direction Lt with respect to the film width direction Lt, and are inclined toward the film longitudinal direction Lf. By inclining the first arrangement direction L1 of the film with respect to the film longitudinal direction Lf, the distance between adjacent conductive particles in the width direction and the longitudinal direction of the terminal portion 17a is made dense, and the capture rate is further improved.

Next, examples of the present invention will be described. In this embodiment, an anisotropic conductive film in which the conductive particles are regularly arranged and an anisotropic conductive film in which the conductive particles are randomly dispersed are used, and the evaluation IC is connected to the evaluation glass substrate. A body sample was prepared, and the number of conductive particles captured between the substrate electrode formed on the evaluation glass substrate and the IC bump formed on the evaluation IC and the closest particle of the conductive particles were used. Distance (inter-particle distance), number of conductive particles in the inter-bump space between adjacent IC bumps, distance from the closest particles of the conductive particles (inter-particle distance), initial conduction resistance, between adjacent IC bumps The short circuit rate was measured.

[Animate conductive film]
The binder resin layer of the anisotropic conductive film used to connect the evaluation IC is a phenoxy resin (trade name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.) by 60 parts by mass, and an epoxy resin (trade name: jER828, manufactured by Mitsubishi Chemical Co., Ltd.). A binder resin composition was prepared by adding 40 parts by mass and 2 parts by mass of a cationic curing agent (trade name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.) to a solvent, and this binder resin composition was applied onto a release film. , Formed by firing.

[Evaluation IC]
As the evaluation element, an evaluation IC having an outer shape; 1.8 mm × 20 mm, a thickness of 0.5 mm, a bump (Au-plated); a width of 30 μ × a length of 85 μm, a height of 15 μm, and a space width between bumps: 50 μm was used.

[Glass substrate for evaluation]
As the evaluation glass substrate to which the evaluation IC is connected, an ITO pattern glass having an outer shape; 30 mm × 50 mm, a thickness of 0.5 mm, and a comb-shaped electrode pattern having the same size and pitch as the bump of the evaluation IC is used. board.

After temporarily attaching the anisotropic conductive film to this evaluation glass substrate, the evaluation IC is mounted while aligning the IC bump and the substrate electrode, and thermocompression bonding is performed at 180 ° C., 80 MPa, and 5 sec by the thermocompression bonding head. By doing so, a connection sample was created. For each connector sample, the number of trapped conductive particles and the distance between particles sandwiched between the IC bump and the substrate electrode, the number of conductive particles in the space between bumps between adjacent IC bumps, and the distance between particles. The distance, initial conduction resistance, and short circuit occurrence rate between adjacent IC bumps were measured.

The number of trapped conductive particles sandwiched between the IC bump and the substrate electrode is determined by observing the indentation appearing on the substrate electrode from the back surface of the evaluation glass substrate for each connector sample, and pairing the IC bump and the substrate. The number of conductive particles trapped between the electrodes was measured for any 100 IC bumps and substrate electrodes, and the average was calculated. Similarly, for the interparticle distance of the conductive particles captured between the IC bump and the substrate electrode, the indentation appearing on the substrate electrode is observed from the back surface of the evaluation glass substrate, and any 100 IC bumps and the substrate electrode are observed. Was measured, and the average and minimum distances were calculated.

The number of conductive particles in the inter-bump space was observed from the back surface of the evaluation glass substrate for each connection sample, measured for any 100 inter-bump spaces, and the average was calculated. Similarly, the inter-particle distance of the conductive particles in the inter-bump space was observed from the back surface of the evaluation glass substrate, measured for any 100 inter-bump spaces, and the average and minimum distances were obtained. It should be noted that, on the same observation surface, those deviated in the depth direction were roughly calculated from the measured values.

Further, each connected sample was evaluated as having a good initial conduction resistance of 0.5 Ω or less and a short circuit occurrence rate between IC bumps of 50 ppm or less.

[Example 1]
In Example 1, an anisotropic conductive film in which conductive particles were regularly arranged in a binder resin layer was used. In the anisotropic conductive film used in Example 1, an adhesive is applied on a stretchable sheet, conductive particles are arranged in a lattice pattern and evenly in a single layer, and then the sheet is subjected to a desired draw ratio. It was produced by laminating a binder resin layer in a state of being stretched in. The conductive particles used (trade name: AUL704, manufactured by Sekisui Chemical Co., Ltd.) have a particle diameter of 4 μm, a distance between particles before connection is 0.5 μm, and a particle number density is 28,000 particles / mm ² .

[Example 2]
In Example 2, the same conditions as in Example 1 were used except that an anisotropic conductive film having a particle distance of 1 μm and a particle number density of 16000 / mm ² before connection was used.

[Example 3]
In Example 3, the same conditions as in Example 1 were used except that an anisotropic conductive film having a particle-to-particle distance of 1.5 μm and a particle number density of 10500 / mm ² before connection was used.

[Example 4]
In Example 4, the same conditions as in Example 1 were used except that an anisotropic conductive film having a particle distance of 3 μm and a particle number density of 5200 particles / mm ² before connection was used.

[Example 5]
In Example 5, the same conditions as in Example 1 were used except that an anisotropic conductive film having a particle distance of 0.5 μm and a particle number density of 50,000 particles / mm ² before connection was used.

[Comparative Example 1]
In Comparative Example 1, an anisotropic conductive film in which conductive particles are randomly dispersed in a binder resin layer is obtained by adding conductive particles to a binder resin composition to prepare the binder resin composition, applying the mixture onto a release film, and firing the mixture. Using. The conductive particles used (trade name: AUL704, manufactured by Sekisui Chemical Co., Ltd.) have a particle diameter of 4 μm and a particle number density of 100,000 particles / mm ² .

[Comparative Example 2]
In Comparative Example 2, the conditions were the same as those in Comparative Example 1 except that the particle number density was 16000 particles / mm ² .

As shown in Table 1, in the connector samples according to Examples 1 to 5, the number of conductive particles sandwiched between the IC bumps of the pair of evaluation ICs and the substrate electrodes of the evaluation glass substrate is 8 on average. It was 0.1 or more, and the initial conduction resistance was 0.4Ω or less, which was good. The interparticle distance of the conductive particles sandwiched between the pair of IC bumps and the substrate electrodes was 1.2 μm or more on average, and 0.2 μm or more at the minimum.

Further, in the connection sample according to Examples 1 to 5, the number of conductive particles in the space between bumps extending between adjacent IC bumps was divided into 14.3 to 194.2 on average, but the particles of conductive particles. The average distance was 1.4 μm or more, and the minimum was 0.3 μm. The short-circuit occurrence rate between IC bumps was lower than 50 ppm, and the insulating property was also good.

On the other hand, in Comparative Example 1, since the conductive particles filled with the number density of 100,000 / mm ² are randomly dispersed in the binder resin layer, the conductive particles sandwiched between the substrate electrode and the IC bump. The number was 48 on average, the distance between particles was 0.5 μm on average, the minimum distance was 0 μm, and the initial conduction resistance was 0.2 Ω, which was not a problem. On the other hand, in the space between bumps, the number of conductive particles is 80 on average, the distance between particles is 0.7 μm on average, and the minimum distance is 0 μm, that is, contact between conductive particles is observed, and the occurrence rate of short circuit between bumps is observed. Was 1000 ppm or more.

Further, in Comparative Example 2, since the conductive particles filled with a number density of 16000 / mm ² are randomly dispersed, the average number of conductive particles in the space between bumps is 12.8, and the particles are particles. The average distance was 2.6 μm and the minimum distance was 0 μm. That is, although conductive particles were in contact with each other, the occurrence rate of short circuit between bumps was 50 ppm or less. On the other hand, the number of conductive particles sandwiched between the substrate electrode and the IC bump is 7.7 on average, the distance between particles is 2.1 μm on average, the minimum distance is 0 μm, and the conduction resistance is as high as 5Ω. rice field.

In Example 4, the number density of the conductive particles was 5000 particles / mm ² , but when the conduction resistance was larger than 0.5 Ω, it was a defect, but it was 0.4 Ω, which was not a problem in practical use. Further, in Example 5, the number density of the conductive particles was 50,000 particles / mm ² , but when the number of shorts between the bumps was larger than 50 ppm, it was defective, but it was 50 ppm or less, and there was no problem in practical use. That is, it can be seen that the number density of the conductive particles before the adhesion of the anisotropic conductive film is preferably 5000 to 60,000 / mm ² .

When counting the number of conductive particles captured by the bumps from the indentation, it is common to observe from the substrate side as described above. At this time, few of the conductive particles in the space between the bumps are present on the same plane as the conductive particles captured by the bumps. This is presumed to be the effect of flow.

1 Anisotropic conductive film, 2 Peeling film, 3 Binder resin layer, 4 Conductive particles, 6 Winding reel, 10 Liquid crystal display panel, 11, 12 transparent substrate, 12a edge, 13 seal, 14 liquid crystal, 15 panel display , 16,17 Transparent electrode, 17a terminal part, 18 LCD drive IC, 18a mounting surface, 19 electrode terminal, 20 COG mounting part, 21 board side alignment mark, 22 IC side alignment mark, 23 terminal space, 33 heat Crimping head

Claims (6)

In a connector in which electronic components are connected on a circuit board via an anisotropic conductive adhesive,
In the above anisotropic conductive adhesive, conductive particles are arranged on a binder resin, and the conductive particles are arranged.
The connection electrode formed on the electronic component and the substrate electrode formed on the circuit board are displaced in the arrangement direction of the connection electrode and the substrate electrode, and the minimum distance in the arrangement direction of the connection electrode and the substrate electrode. Is less than 4 times the particle size of the conductive particles.
The interparticle distance between the conductive particles in the space between the connection electrodes formed on the electronic component is the distance between the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode. Longer than the distance between particles,
The extrinsic line in the longitudinal direction of the substrate electrode of the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode is captured adjacent to the longitudinal direction. A connector that penetrates particles. The connector according to claim 1, wherein the anisotropic conductive adhesive is an anisotropic conductive film in which the conductive particles are regularly arranged. The second aspect of claim 2, wherein the conductive particles are arranged in the film width direction and inclined with respect to the film width direction, and the arrangement direction in the film longitudinal direction is inclined with respect to the film longitudinal direction. Connection body. Electronic components are mounted on the circuit board via an adhesive containing conductive particles.
In a method for manufacturing a connector for connecting an electronic component on a circuit board by pressing the electronic component against the circuit board and curing the adhesive.
In the above adhesive, conductive particles are arranged on the binder resin, and the adhesive particles are arranged.
The connection electrode formed on the electronic component and the substrate electrode formed on the circuit board are displaced in the arrangement direction of the connection electrode and the substrate electrode, and the minimum distance in the arrangement direction of the connection electrode and the substrate electrode. Is less than 4 times the particle size of the conductive particles.
The interparticle distance between the conductive particles in the space between the connection electrodes is the distance between the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode formed on the electronic component. Longer than the distance between particles,
The extrinsic line in the longitudinal direction of the substrate electrode of the conductive particles captured between the substrate electrode formed on the circuit board and the connection electrode is captured adjacent to the longitudinal direction. A method for manufacturing a connector that penetrates particles. The method for manufacturing a connector according to claim 4, wherein the adhesive is an anisotropic conductive film in which the conductive particles are regularly arranged. The fifth aspect of claim 5, wherein the conductive particles are arranged in the film width direction and inclined with respect to the film width direction, and the arrangement direction in the film longitudinal direction is inclined with respect to the film longitudinal direction. How to make a connection.

Images