Connector, method for manufacturing a connector, and inspection method

Abstract

The visual recognition of the indentations is improved, and the inspection after connection in the connection process using the anisotropic conductive film is performed rapidly and accurately. A transparent substrate and an electronic component connected to the transparent substrate via an anisotropic conductive adhesive are provided. In the terminal of the transparent substrate, a plurality of indentations (30) caused by conductive particles contained in the anisotropic conductive adhesive are arranged in the in-plane direction.

Description

[0001] This application is a divisional application of the following invention patent application:

[0002] Invention title: Connector, manufacturing method and inspection method of connector; Application number: 201580010878.6; Application date: February 26, 2015. Technical Field

[0003] This invention relates to a connector for connecting electronic components and a transparent substrate, and particularly to a connector for connecting electronic components to a transparent substrate via an adhesive containing conductive particles, a method for manufacturing the connector, and a method for inspecting the connector. This application claims priority based on Japanese Patent Application No. 2014-036743, filed February 27, 2014, and Japanese Patent Application No. 2015-034548, filed February 24, 2015, both of which are incorporated herein by reference. Background Technology

[0004] Liquid crystal displays (LCDs) or organic EL panels have traditionally been used in various display units such as televisions, PC monitors, mobile phones, smartphones, portable game consoles, tablets, wearable devices, and in-vehicle monitors. In recent years, driven by the desire for miniaturization and thinner designs, new construction methods have emerged for such display devices. These methods involve directly mounting driver ICs onto the glass substrate of the display panel using anisotropic conductive film (ACF), or directly mounting flexible substrates that form the driver circuitry onto the glass substrate.

[0005] On a glass substrate on which ICs and flexible substrates are mounted, multiple transparent electrodes made of indium tin oxide (ITO) are formed, and electronic components such as ICs and flexible substrates are connected to these transparent electrodes. The electronic components connected to the glass substrate have multiple electrode terminals formed on their mounting surfaces corresponding to the transparent electrodes. These terminals are thermo-pressed onto the glass substrate through an anisotropic conductive film, thereby connecting the electrode terminals and the transparent electrodes.

[0006] Anisotropic conductive films are formed by incorporating conductive particles into an adhesive resin. Electrical conduction between two conductors is achieved through heating and pressing, with the conductive particles maintaining the mechanical connection between the conductors. The adhesive resin is used as the adhesive for the anisotropic conductive film. Typically, a highly reliable thermosetting adhesive resin is used, but photocurable adhesive resins or photo-thermal adhesive resins can also be used.

[0007] When connecting electronic components to a transparent electrode via such anisotropic conductive film, firstly, the anisotropic conductive film is temporarily attached to the transparent electrode on a glass substrate using a temporary pressing unit (not shown). Next, the electronic components are mounted on the glass substrate via the anisotropic conductive film to form a temporary connector. Then, the electronic components and the anisotropic conductive film are heated and pressed together toward the transparent electrode using a thermoforming unit such as a thermoforming joint. Through heating using this thermoforming joint, the anisotropic conductive film undergoes a thermosetting reaction, thereby bonding the electronic components to the transparent electrode.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent No. 4789738

[0011] Patent Document 2: Japanese Patent Application Publication No. 2004-214374

[0012] Patent document 3: Japanese Patent Application Publication No. 2005-203758. Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] Furthermore, in the connection process utilizing this anisotropic conductive film, the heating and pressing process of the connection points for the connected electronic components typically involves large-area heating and pressing rather than multiple mounting parts. This is because the connection points of the electronic components are relatively small compared to the area of ​​the connected electronic components, and also because the multiple electrode terminals (protrusions) arranged at the connection points require parallelism, etc.

[0015] Therefore, in the connection process using anisotropic conductive films, from the point of view of improving productivity, it is necessary not only to shorten the connection process itself, but also to speed up the inspection process that accompanies the shortened connection time.

[0016] Post-connection inspection is a process to confirm that conductivity is ensured by crushing conductive particles between the electrode terminals of the electronic component and the transparent electrode of the glass substrate. When expedited, this is sometimes performed by visually inspecting the indentations of the conductive particles on the transparent electrode from the back of the glass substrate. Additionally, post-connection inspection involves visually inspecting the state of the indentations, the presence of adhesive floats around them, and the state of peeling, either directly or using photographic images.

[0017] The condition of the indentation is determined by comparison with the surrounding area where there are no conductive particles. As a mechanical criterion, it can be judged by observing differences in contrast and color matching. However, if conductive particles overlap between the electrode terminal and the transparent electrode, or if conductive particles are continuously in contact with or excessively close to the transparent electrode in the in-plane direction, it affects the identification of the indentation and its surrounding area—that is, the contrast and color matching—resulting in poor visual recognition and potentially hindering rapid and accurate visual inspection.

[0018] Therefore, the present invention aims to provide a connector, a method for manufacturing the connector, and a method for inspecting the connector, which improves the visual recognizability of the indentation and enables rapid and accurate inspection of the connector after connection in the connection process using anisotropic conductive films.

[0019] Solution for solving the problem

[0020] To solve the above-mentioned problems, the connector according to the present invention includes: a transparent substrate; and an electronic component connected to the transparent substrate via an anisotropic conductive adhesive, wherein in the terminals of the transparent substrate, a plurality of indentations caused by conductive particles contained in the anisotropic conductive adhesive are arranged in the in-plane direction.

[0021] Furthermore, the manufacturing method of the connector according to the present invention involves mounting an electronic component on a circuit board via an adhesive containing conductive particles, pressing the electronic component against the circuit board, and hardening the adhesive to connect the electronic component to the circuit board. In the manufacturing method of the connector, the anisotropic conductive adhesive contains conductive particles arranged in an adhesive resin, and in the terminals of the transparent substrate, the multiple indentations caused by the conductive particles are arranged in the in-plane direction.

[0022] Furthermore, the inspection method of the present invention inspects the connection status of an electronic component connected to a transparent substrate via an anisotropic conductive adhesive containing conductive particles. In the above inspection method, the connection status is inspected by comparing the indentation of conductive particles contained in the anisotropic conductive adhesive at the terminals of the transparent substrate and the peripheral portion of the indentation.

[0023] Invention Effects

[0024] According to the present invention, conductive particles are arranged within the terminals, so that each indentation appears independently. Therefore, the indentations appearing on the terminals become easily identifiable due to their clear contrast and significantly improved visual recognizability, enabling rapid and accurate inspection of the connectivity between the indented electronic components and the terminals of the transparent substrate. Attached Figure Description

[0025] Figure 1This is a cross-sectional view of a liquid crystal display panel shown as an example of a connector.

[0026] Figure 2 This is a bottom view showing the state of the indentations on the input / output terminals when viewed from the back of a transparent substrate.

[0027] Figure 3 This is a cross-sectional view showing the connection process between the liquid crystal driving IC and the transparent substrate.

[0028] Figure 4 This is a plan view showing the electrode terminals (bumps) of an IC for driving a liquid crystal display and the space between the terminals.

[0029] Figure 5 This is a cross-sectional view showing anisotropic conductive film.

[0030] Figure 6 It is a plan view showing an anisotropic conductive film in which conductive particles are arranged in a regular lattice pattern.

[0031] Figure 7 It is a planar diagram showing an anisotropic conductive film in which conductive particles are regularly arranged in a hexagonal lattice.

[0032] Figure 8 The diagram shows a plan view of the indentation that appears on the terminal. (A) shows the case of using an anisotropic conductive film with randomly dispersed conductive particles, and (B) shows the case of using an anisotropic conductive film with conductive particles arranged in a certain order.

[0033] Figure 9 This is a plan view showing the input / output terminal array.

[0034] Figure 10 It is a cross-sectional view showing the state in which the conductive particles are held by protrusions and terminals forming a concave-convex portion with a height difference within 50% of the particle size.

[0035] Figure 11 It is a cross-sectional view showing the state in which the conductive particles are held by protrusions and terminals forming a concave-convex portion with a height difference within 50% of the particle size.

[0036] Figure 12 It is a cross-sectional view showing the state in which conductive particles are held by protrusions and terminals forming a concave-convex portion having a height difference of more than 50% over the particle size of the conductive particles.

[0037] Figure 13 It is a cross-sectional view showing the state in which conductive particles are held by protrusions and terminals forming a concave-convex portion having a height difference of more than 50% over the particle size of the conductive particles. Detailed Implementation

[0038] Hereinafter, with reference to the accompanying drawings, the connector, the method for manufacturing the connector, and the method for inspecting the connector to which the present invention is applied will be described in detail. Furthermore, the present invention is not limited to the embodiments described below, and various modifications can obviously be made without departing from the essential points of the invention. Additionally, the drawings are schematic, and the proportions of various dimensions may differ from reality. Specific dimensions should be determined with reference to the following description. Furthermore, it should be understood that the drawings also include portions with different dimensional relationships or proportions.

[0039] [LCD display panel]

[0040] Hereinafter, a liquid crystal display panel, in which an IC chip for driving a liquid crystal is mounted on a glass substrate as an electronic component, will be described as an example of a connector to which the present invention is applied. This liquid crystal display panel 10 is as follows: Figure 1 As shown, two transparent substrates 11 and 12, made of glass substrates or the like, are arranged opposite each other and are bonded together by a frame-shaped sealing material 13. Furthermore, the liquid crystal display panel 10 forms a panel display section 15 by sealing liquid crystal 14 into the space surrounded by the transparent substrates 11 and 12.

[0041] The transparent substrates 11 and 12 are formed on their opposing inner surfaces such that a pair of transparent electrodes 16 and 17 in a stripe pattern made of ITO (indium tin oxide) or the like intersect each other. Furthermore, the two transparent electrodes 16 and 17 form pixels, which are the smallest units of a liquid crystal display, through the intersection of these two transparent electrodes 16 and 17.

[0042] Of the two transparent substrates 11 and 12, one transparent substrate 12 is formed with a planar dimension larger than that of the other transparent substrate 11. At the edge 12a of the larger transparent substrate 12, a mounting portion 27 is provided for mounting a liquid crystal driving IC 18 as an electronic component. Furthermore, as... Figure 2 , Figure 3 As shown, the mounting portion 27 has an input terminal array 20a with a plurality of input terminals 19a arranged with transparent electrodes 17 and an output terminal array 20b with a plurality of output terminals 19b arranged with output terminals, and a substrate side alignment mark 31 that overlaps with the IC side alignment mark 32 provided on the liquid crystal driving IC 18.

[0043] The liquid crystal driver IC18 selectively applies liquid crystal driving voltage to pixels, locally changing the orientation of the liquid crystal to achieve a predetermined liquid crystal display. Additionally, as... Figure 3 , Figure 4As shown, the liquid crystal driving IC 18 has an input bump array 22a on its mounting surface 18a to the transparent substrate 12, consisting of multiple input bumps 21a that are electrically connected to the input terminals 19a of the transparent electrode 17, and an output bump array 22b consisting of multiple output bumps 21b that are electrically connected to the output terminals 19b of the transparent electrode 17. The input bumps 21a and output bumps 21b are preferably, for example, copper bumps, gold bumps, or bumps that are gold-plated onto copper bumps.

[0044] The input bumps 21a are arranged in a row along one side edge of the mounting surface 18a, for example, and the output bumps 21b are arranged in multiple rows in an alternating manner along another side edge opposite to one side edge. The input and output bumps 21a and 21b and the input and output terminals 19a and 19b provided on the mounting portion 27 of the transparent substrate 12 are formed in the same number and at the same spacing, and are connected to the transparent substrate 12 and the liquid crystal driving IC 18 by alignment connection.

[0045] In addition, the arrangement of the input and output bumps 21a and 21b, besides Figure 4 In addition to the configuration shown, the input / output bumps 21a and 21b can also be arranged in one or more columns on one side edge and one or more columns on the other side edge. Furthermore, the input / output bumps 21a and 21b can be arranged in a straight line where the parallel and adjacent electrode terminals of the multiple columns are parallel to each other, or they can be arranged in an alternating pattern where the parallel and adjacent electrode terminals of the multiple columns are uniformly staggered.

[0046] Furthermore, the LCD driver IC18 can also arrange input / output bumps 21a and 21b along the long side of the IC substrate and form side bumps along the short side of the IC substrate. In addition, the input / output bumps 21a and 21b can be formed with the same size or with different sizes. Furthermore, the input / output bump rows 22a and 22b can be arranged symmetrically or asymmetrically with the same size, or with asymmetrically arranged with different sizes.

[0047] Furthermore, with the miniaturization and increasing functionality of liquid crystal display devices and other electronic devices in recent years, electronic components such as the liquid crystal driver IC18 are also required to be miniaturized and lowered, and the height of the input and output bumps 21a and 21b is also getting lower (e.g., 6 to 15 μm).

[0048] Furthermore, the liquid crystal driver IC 18 has an IC-side alignment mark 32 formed on its mounting surface 18a, which is used to align the transparent substrate 12 by overlapping with the substrate-side alignment mark 31. In addition, since the wiring spacing of the transparent electrodes 17 of the transparent substrate 12 or the input / output bumps 21a and 21b of the liquid crystal driver IC 18 are miniaturized, high-precision alignment adjustment is required between the liquid crystal driver IC 18 and the transparent substrate 12.

[0049] The substrate-side alignment mark 31 and the IC-side alignment mark 32 can be used to achieve alignment between the transparent substrate 12 and the liquid crystal driving IC 18 by combining various marks.

[0050] An anisotropic conductive film 1 is used as an adhesive for circuit connection on the input / output terminals 19a and 19b of the transparent electrode 17 formed in the mounting portion 27 to connect the liquid crystal driver IC 18. The anisotropic conductive film 1 contains conductive particles 4, which electrically connect the input / output bumps 21a and 21b of the liquid crystal driver IC 18 and the input / output terminals 19a and 19b of the transparent electrode 17 formed in the mounting portion 27 of the transparent substrate 12 via the conductive particles 4. The anisotropic conductive film 1 is thermopressed by the thermo-press joint 33, causing the adhesive resin to flow. As a result, the conductive particles 4 are compressed between the input / output terminals 19a and 19b and the input / output bumps 21a and 21b of the liquid crystal driver IC 18, and the adhesive resin hardens in this state. Thus, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 and the liquid crystal driver IC 18.

[0051] Furthermore, an alignment film 24, which has undergone a predetermined rubbing treatment, is formed on the two transparent electrodes 16 and 17 to define the initial orientation of the liquid crystal molecules. Moreover, a pair of polarizing plates 25 and 26 are disposed on the outer side of the two transparent substrates 11 and 12 to define the vibration direction of transmitted light from a light source (not shown) such as a backlight.

[0052] [Anisotropic conductive film]

[0053] Next, the anisotropic conductive film 1 will be described. For example... Figure 5As shown, the anisotropic conductive film (ACF) 1 typically forms an adhesive resin layer (adhesive layer) 3 containing conductive particles 4 on a release film 2, which serves as the substrate material. The anisotropic conductive film 1 is a thermosetting or photocurable adhesive, such as a UV-curable adhesive, and is adhered to the input / output terminals 19a and 19b formed on the transparent substrate 12 of the liquid crystal display panel 10, and a liquid crystal driver IC 18 is mounted thereon. It flows under heat pressure using a thermo-pressurized joint 33, causing the conductive particles 4 to collapse between the input / output terminals 19a and 19b of the opposing transparent electrodes 17 and the input / output bumps 21a and 21b of the liquid crystal driver IC 18. It hardens under these collapsed conductive particles by heating or UV irradiation. Thus, the anisotropic conductive film 1 connects the transparent substrate 12 and the liquid crystal driver IC 18, enabling them to conduct electricity.

[0054] In addition, the anisotropic conductive film 1 has conductive particles 4 arranged in a predetermined pattern on a common adhesive resin layer 3 containing film-forming resin, thermosetting resin, latent curing agent, silane coupling agent, etc.

[0055] The release film 2 supporting the adhesive resin layer 3 is formed by coating a release agent such as silicone onto PET (polyethylene terephthalate), OPP (oriented polypropylene), PMP (poly-4-methylpentene-1), PTFE (polytetrafluoroethylene), etc., and not only prevents the anisotropic conductive film 1 from drying out, but also maintains the shape of the anisotropic conductive film 1.

[0056] The film-forming resin contained in the adhesive resin layer 3 is preferably a resin with an average molecular weight of about 10,000 to 80,000. Various resins such as epoxy resin, modified epoxy resin, urethane resin, and phenoxy resin can be cited as film-forming resins. Among these, phenoxy resin is particularly preferred from the viewpoints of film formation state and bonding reliability.

[0057] As a thermosetting resin, there are no particular limitations; examples include commercially available epoxy resins and acrylic resins.

[0058] There are no particular limitations on epoxy resins, but examples include naphthalene-type epoxy resins, biphenyl-type epoxy resins, phenolic varnish-type epoxy resins, bisphenol-type epoxy resins, stilbene-type epoxy resins, pyromethane-type epoxy resins, phenolic aralkyl-type epoxy resins, naphthol-type epoxy resins, dimercyclopentadiene-type epoxy resins, and triphenylmethane-type epoxy resins. These can be used alone or in combination of two or more.

[0059] As for acrylic resins, there are no particular restrictions; acrylic compounds, liquid acrylates, etc., can be appropriately selected according to the purpose. Examples include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethyloltricyclodecane diacrylate, 1,4-butanediol tetraacrylate, 2-hydroxy-1,3-diacryloyloxypropane, 2,2-bis[4-(acryloyloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloyloxyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, resinous (acryloyloxyethyl) isocyanurate, urethane acrylate, epoxy acrylate, etc. Furthermore, materials in which the acrylate is methacrylate can also be used. These can be used alone or in combination of two or more.

[0060] There are no particular limitations on latent curing agents, but various curing agents such as heat-curing and UV-curing types can be cited. Latent curing agents typically do not react; they are activated by various initiation conditions selected based on their intended use, such as heat, light, or pressure, and thus begin a reaction. Activation methods for heat-active latent curing agents include: methods that generate active species (cations, anions, free radicals) through heating and dissociation reactions; methods that stably disperse the curing agent in epoxy resin near room temperature and then dissolve / melt it with the epoxy resin at high temperatures, initiating a curing reaction; methods that melt out molecular sieve-encapsulated curing agents at high temperatures and initiate a curing reaction; and melting / curing methods using microcapsules, etc. Heat-active latent curing agents include imidazoles, hydrazides, boron trifluoride-amine complexes, sulfonium salts, aminated imides, polyamine salts, dicyandiamide, etc., or their modified forms; these can be used alone or in mixtures of two or more. Microencapsulated imidazole latent curing agents are preferred.

[0061] There are no particular limitations on silane coupling agents, but examples include epoxy, amine, mercapto / sulfide, and urea compounds. Adding silane coupling agents improves the adhesion between organic and inorganic materials at the interface.

[0062] [Conductive particles]

[0063] As the conductive particle 4, any known conductive particle used in the anisotropic conductive film 1 can be used. Examples of conductive particles 4 include particles of various metals or metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, and gold; particles on which metal is deposited on the surface of particles made of metal oxides, carbon, graphite, glass, ceramics, or plastics; or particles on which an insulating film is further deposited. In the case where metal particles are deposited on the surface of resin particles, examples of resin particles include epoxy resin, phenolic resin, acrylic resin, acrylonitrile styrene (AS) resin, styrene-based melamine resin, divinylbenzene resin, and styrene resin. The size of the conductive particle 4 is preferably 1 to 10 μm, but the present invention is not limited thereto.

[0064] [The regular arrangement of conductive particles]

[0065] In the anisotropic conductive film 1, the conductive particles 4 are arranged regularly in a predetermined pattern when viewed from above, for example, as shown in the figure. Figure 6 or Figure 7 As shown, the conductive particles 4 are arranged in a grid pattern and uniformly, or in a hexagonal grid pattern. The arrangement distance of such conductive particles 4 can be adjusted appropriately. That is, different arrangement distances can be used depending on the direction of arrangement. As will be described later, by arranging them regularly when viewed from above, compared to the case where the anisotropic conductive film 1 and the conductive particles 4 are randomly dispersed, the visual recognition of the indentations 30 appearing on the input / output terminals 19a and 19b can be improved during inspection after the connection of the liquid crystal driving IC 18.

[0066] On the other hand, when conductive particles are randomly dispersed, they may become adjacent or repeat when connected to each other, making it difficult to identify individual conductive particles after pressing.

[0067] Furthermore, because the anisotropic conductive film 1 is regularly arranged when viewed from above, compared to the case where the conductive particles 4 are randomly dispersed, the space 23 between adjacent input / output bumps 21a and 21b of the liquid crystal driver IC 18 will be smaller, thereby reducing the area between terminals. Even if the conductive particles 4 are filled with high density, short circuits between bumps in the space 23 between the input / output bumps 21a and 21b caused by the agglomeration of conductive particles 4 can be prevented during the connection process of the liquid crystal driver IC 18.

[0068] Furthermore, in the anisotropic conductive film 1, the conductive particles 4 are arranged in a regular pattern, thereby preventing the agglomeration of conductive particles 4 and the resulting uneven density even when the adhesive resin layer 3 is filled with a high density. Therefore, based on the anisotropic conductive film 1, conductive particles 4 can also be captured in the finely pitched input / output terminals 19a, 19b or input / output bumps 21a, 21b. The uniform arrangement pattern of the conductive particles 4 can be arbitrarily set.

[0069] Such anisotropic conductive film 1 can be manufactured by, for example, by coating an adhesive on a stretchable sheet and arranging conductive particles 4 in a single layer thereon and then stretching the sheet at a desired elongation ratio; by arranging conductive particles 4 in a predetermined pattern on a substrate and then transferring conductive particles 4 to an adhesive resin layer 3 supported by a release film 2; or by supplying conductive particles 4 to the adhesive resin layer 3 supported by the release film 2 via an arrangement plate having openings corresponding to the arrangement pattern.

[0070] Furthermore, the shape of the anisotropic conductive film 1 is not particularly limited, but as... Figure 5 The device shown can be made into a long strip shape, for example, that can be wound onto the reel 6 and cut to a predetermined length for use.

[0071] Furthermore, in the above embodiment, the anisotropic conductive film 1 was described as an example of an adhesive film formed from a thermosetting resin composition in which conductive particles 4 are regularly arranged in an adhesive resin layer 3. However, the adhesive involved in this invention is not limited to this, and can be, for example, a structure in which an insulating adhesive layer composed only of adhesive resin 3 and a conductive particle layer composed of adhesive resin 3 in which conductive particles 4 are regularly arranged are laminated. In addition, as long as the conductive particles 4 are regularly arranged in a top view, the anisotropic conductive film 1 can be further described as follows: Figure 5 In addition to the single-layer arrangement shown, the conductive particles 4 can also be arranged in a regular pattern across multiple adhesive resin layers 3, and viewed from above. Furthermore, the anisotropic conductive film 1 can be uniformly dispersed at a predetermined distance within at least one layer of a multilayer structure.

[0072] [Connection Process]

[0073] Next, the connection process of connecting the liquid crystal driving IC 18 to the transparent substrate 12 will be described. First, an anisotropic conductive film 1 is temporarily attached to the mounting portion 27 of the transparent substrate 12 where input / output terminals 19a and 19b are formed. Next, the transparent substrate 12 is supported on the platform of the connection device, and the liquid crystal driving IC 18 is placed on the mounting portion 27 of the transparent substrate 12 via the anisotropic conductive film 1.

[0074] Next, the adhesive resin layer 3 is heated to a predetermined temperature to harden the adhesive resin layer 3, and then subjected to thermal pressurization at a predetermined pressure and time from the liquid crystal driver IC 18. As a result, the adhesive resin layer 3 of the anisotropic conductive film 1 exhibits fluidity and flows out between the mounting surface 18a of the liquid crystal driver IC 18 and the mounting portion 27 of the transparent substrate 12. The conductive particles 4 in the adhesive resin layer 3 are trapped between the input / output bumps 21a and 21b of the liquid crystal driver IC 18 and the input / output terminals 19a and 19b of the transparent substrate 12 and are crushed.

[0075] As a result, an electrical connection is established by clamping the conductive particles 4 between the input / output bumps 21a, 21b and the input / output terminals 19a, 19b, and the adhesive resin heated by the thermocompression joint 33 in this state hardens. Thus, a liquid crystal display panel 10 can be manufactured that ensures conductivity between the input / output bumps 21a, 21b of the liquid crystal driving IC 18 and the input / output terminals 19a, 19b formed on the transparent substrate 12. Furthermore, the pressure (strain) applied to the clamped conductive particles 4 creates indentations within the input / output terminals 19a, 19b.

[0076] The conductive particles 4, which are not located between the input / output bumps 21a and 21b and the input / output terminals 19a and 19b, are dispersed in the adhesive resin within the space 23 between adjacent input / output bumps 21a and 21b, maintaining an electrically insulating state. Therefore, the liquid crystal display panel 10 achieves electrical conduction only between the input / output bumps 21a and 21b of the liquid crystal driving IC 18 and the input / output terminals 19a and 19b of the transparent substrate 12. Furthermore, as the adhesive resin, a fast-curing type adhesive resin based on free radical polymerization is used, enabling the adhesive resin to cure rapidly within a short heating time. Additionally, as the anisotropic conductive film 1, it is not limited to a thermosetting type; as long as pressure bonding is possible, a photocuring type or a photothermal type adhesive can also be used.

[0077] [Visual recognition of indentations]

[0078] Since the conductive particles 4 are pressed between the input / output bumps 21a and 21b, indentations 30 can be observed at the input / output terminals 19a and 19b from the transparent substrate 12 side. After connecting the liquid crystal driver IC 18, the connectivity can be checked by visual inspection (microscope, etc.) or by photographic image from the back of the transparent substrate 12 (the side opposite to the input / output terminals 19a and 19b).

[0079] The indentation 30 is created by pressing with a thermoforming joint 33 while the input / output bumps 21a, 21b are positioned between the input / output protrusions 21a, 21b and the input / output terminals 19a, 19b, trapping highly conductive particles 4. This indentation leaves a mark on the conductive particles 4 at the input / output terminals 19a, 19b of the transparent electrode 17, which can be visually identified by observation from the back side of the transparent substrate 12. The indentation 30 generally has a diameter greater than or equal to the particle size of the conductive particles 4. Figure 8 As shown in (a), it becomes approximately circular. Additionally, the shape of the indentation 30 is as follows: Figure 8 As shown in (b), the shape is generally unilaterally blurred and mostly composed of curves. In this case, the curves should be recognizable as approximately circular curves, with at least 40%, preferably 50%, and more preferably 60% or more of the circular shape. Furthermore, in the case of metal particles, there may be cases that include linear states.

[0080] Because the intensity of particle pressing varies, the contrast and outer diameter of the indentation 30 are different. Therefore, the indentation becomes a criterion for determining whether the pressing made by the thermocouple 33 is uniform between and within each input / output terminal 19a, 19b.

[0081] Here, in the connector where conductive particles 4 are randomly dispersed in anisotropic conductive film of adhesive resin layer 3 for connection, such as Figure 8 As shown in (c), indentations 30 appear irregularly on the input and output terminals, and they are close together and repeated. Therefore, the visual recognition of indentations 30 is poor, and it takes time to grasp the state, so the inspection takes time, and the judgment accuracy of indentations 30 will decrease. That is, it becomes difficult to identify the curve that forms indentations 30. In addition, when inspecting according to mechanical image processing, it is difficult to set the judgment criteria based on such poor visual recognition. Therefore, the judgment accuracy itself will deteriorate. Because in this case, it will be regarded as a combination of straight lines according to the resolution.

[0082] On the other hand, in the liquid crystal display panel 10 according to the present invention, since it is formed using an anisotropic conductive film 1 with arranged conductive particles 4, the conductive particles 4 are also held in an arranged state within the input / output terminals 19a and 19b, such as... Figure 8 As shown in (a), the indentations 30 appear regularly in an independent manner. Therefore, the indentations 30 appearing on the input / output terminals 19a and 19b clearly exhibit contrast or form their curves, thereby significantly improving the visual recognizability of each indentation 30. Thus, the liquid crystal display panel 10 can quickly and accurately check the connectivity between the input / output bumps 21a and 21b based on the indentations 30 and the input / output terminals 19a and 19b.

[0083] The indentations 30 appearing on the input / output terminals 19a and 19b, if they appear regularly, can ensure visual recognizability through the contrast with the smooth surface where there are no conductive particles 4. Therefore, they can be adjacent to each other, but it is preferable that they are displayed at a predetermined distance, for example, at least 0.2 times the outer diameter, and more preferably at least 0.4 times the outer diameter. In addition, the contrast with the smooth surface also includes the case where they are displayed by curves.

[0084] Such indentations 30 preferably exist independently in 55% or more of a single input / output terminal 19a, 19b, more preferably 65% ​​or more, and even more preferably 75% or more. Independent existence of the indentation 30 means that the conductive particle 4 exists as a single unit, while non-independent existence means that they are adjacent or repeated. However, when multiple conductive particles 4 are intentionally connected and arranged, they are considered independent in that unit.

[0085] In addition, indentation 30 is preferred in Figure 9 In the input / output terminal rows 20a and 20b shown with multiple input / output terminals 19a and 19b arranged as shown, at least 55%, more preferably 65%, and even more preferably 75%, of the central input / output terminals 19aM and 19bM are independently present. Furthermore, when the input / output terminal rows 20a and 20b have an odd number of input / output terminals 19a and 19b, the central input / output terminals 19aM and 19bM refer to the terminals in the very center of the terminal row; when the input / output terminal rows 20a and 20b have an even number of input / output terminals 19a and 19b, the central input / output terminals 19aM and 19bM refer to the two terminals in the very center of the terminal row.

[0086] Similarly, indentation 30 is preferred in Figure 9 In the input / output terminal arrays 20a and 20b shown with multiple input / output terminals 19a and 19b, at both ends of the input / output terminals 19aL, 19aR, 19bL, and 19bR, 55% or more, more preferably 65% ​​or more, and even more preferably 75% or more, are independently present. The presence of indentations 30 at 55% or more independently in the input / output terminals 19aL, 19aR, 19bL, and 19bR at both ends suggests that all input / output terminals 19a and 19b of the input / output terminal arrays 20a and 20b possess the same visual recognizability.

[0087] In addition, indentation 30 is preferred in Figure 9In the input / output terminal rows 20a, 20b showing a plurality of input / output terminals 19a, 19b, 55% or more, more preferably 65% ​​or more, and even more preferably 75% or more of the terminals adjacent to the central input / output terminals 19aM, 19bM, are also independently present. Since more than 55% of the indentations 30 are independently present in each of the input / output terminals 19aMs, 19bM adjacent to the central input / output terminals 19aM, 19bM, it can be inferred that the same visual recognizability exists not only in the center of the terminal row, but also in all the input / output terminals 19a, 19b in the entire row.

[0088] Furthermore, indentation 30 is preferred in Figure 9 In the input / output terminal rows 20a, 20b of the array of multiple input / output terminals 19a, 19b shown, 55% or more, more preferably 65% ​​or more, and even more preferably 75% or more of the terminals adjacent to the input / output terminals 19aL, 19aR, 19bL, 19bR at both ends, are independently present. Since more than 55% of the indentations 30 are independently present in each of the input / output terminals 19aLs, 19aRs, 19bL, 19bR adjacent to the input / output terminals 19aL, 19aR, 19bL, 19bR at both ends, it can be inferred that the same visual recognizability exists not only at both ends of the terminal row but also in the input / output terminals 19a, 19b throughout the entire row.

[0089] Furthermore, in all the input / output terminals 19a and 19b of the parallel input / output terminal rows 20a and 20b on the transparent substrate, the indentation 30 preferably exists independently in 55% or more, more preferably in 65% or more, and even more preferably in 75% or more. By comparing the indentations of the parallel terminal rows with each other, the uniformity of the pressing surface of the thermo-pressed connector 33 throughout the entire area can also be checked.

[0090] In addition, in order to confirm the electrical connection with the input / output protrusions 21a and 21b, the indentation 30 preferably appears in two or more places for each input / output terminal 19a and 19b, more preferably three or more places, and even more preferably four or more places.

[0091] At least a portion of the indentation 30 appears regularly, thus serving as an indicator. This allows for simultaneous monitoring of the connection status of the adhesive resin used to connect the liquid crystal driver IC 18, in the area held by the input / output terminals 19a, 19b and the input / output bumps 21a, 21b, and in the connection status within the terminal space 23 of adjacent input / output bumps 21a, 21b. Because the indentation 30 is in a visually recognizable state, when floats or the like are generated in the adhesive resin of the input / output terminals 19a, 19b or their surrounding areas, their different transmissivity makes comparison with the indentation 30, which serves as an indicator, easy. Furthermore, in the event of foreign matter infiltrating the connector, the regular arrangement also serves as an indicator, making it easier to detect and pinpoint the location and extent of the impact of these defective foreign objects.

[0092] [The similarity or identical arrangement of indentations between adjacent terminals]

[0093] Furthermore, the liquid crystal display panel 10 preferably has a portion of the arrangement of the indentations 30 between adjacent input / output terminals 19a and 19b that are identical or similar. This allows the liquid crystal display panel 10 to easily compare the relative arrangement of the indentations 30, and also enables the rapid and accurate setting or evaluation of inspection criteria. In particular, when visually inspecting, if the arrangement of the indentations 30 between adjacent input / output terminals 19a and 19b is identical or similar, the evaluation of the indentations can be performed easily and quickly. By repeating this process, the entire area of ​​the pressed surface can be assessed with high precision and ease.

[0094] Furthermore, the arrangement can also make the indentations 30 arranged in a straight line side by side. Identity refers to the indentations arranged in a straight line having the same spacing or length, while similarity refers to variations in the spacing or length of the indentations arranged in a straight line. In this case, in the fine-pitch input / output terminals 19a and 19b, two indentations formed with the minimum number of indentations are also considered an arrangement. Similarity refers to a change in the distance or interval. Because if it becomes a fine-pitch arrangement, the arrangement of the clamped conductive particles can only be considered as a straight line or a near-straight line.

[0095] The liquid crystal display panel 10 uses an anisotropic conductive film 1 with regularly arranged conductive particles 4, and the conductive particles 4 are regularly distributed across the adjacent input / output terminals 19a and 19b. In this state, if it is heated and pressed with the hot-press joint 33, the flowability of the adhesive resin also becomes approximately the same between the adjacent input / output terminals 19a and 19b, so that the arrangement of the indentations 30 can be the same or similar.

[0096] [Distance between indentations within a terminal]

[0097] Furthermore, the indentation 30 preferably ensures that the distance between the indentations of the entire indentation 30 within one input / output terminal 19a, 19b is within ±30% of the average distance between indentations, more preferably within 15%, and even more preferably within 7%. The distance between indentations refers to the shortest distance between the outer edges of the indentation 30 with the shortest distance between its outer edges and those of adjacent indentations 30. The average distance between indentations refers to the average value of the distances between the indentations of the entire indentation 30 within one input / output terminal 19a, 19b. Therefore, in the indentation 30 inspection process of the present invention, the uniformity of pressing within one input / output terminal 19a, 19b can also be checked.

[0098] That is, within a single input / output terminal 19a, 19b, if the distance between the indentations of the entire indentation 30 is within ±30% of the average distance between indentations, the pressing force applied to the conductive particle 4 will be approximately uniform, and the input / output protrusions 21a, 21b and the input / output terminals 19a, 19b will be pressed in parallel, and the deviation in the conduction resistance of each input / output terminal 19a, 19b is considered to be small. On the other hand, within a single input / output terminal 19a, 19b, if the distance between the indentations of the entire indentation 30 exceeds ±30% of the average distance between indentations, the input / output protrusions 21a, 21b and the input / output terminals 19a, 19b are considered not to be pressed in parallel, and the deviation in the conduction resistance between each input / output terminal 19a, 19b is considered to be large.

[0099] [Uniformity of pressure within a terminal row]

[0100] Furthermore, the indentation 30 preferably ensures that the difference between the average distance between indentations within a single input / output terminal 19a, 19b and the average distance between indentations in the central input / output terminals 19aM, 19bM of the terminal array arranging the input / output terminals 19a, 19b is within ±30%, more preferably within 15%, and even more preferably within 7%. Thus, in the indentation 30 inspection process of the present invention, the uniformity of pressing within a single input / output terminal array 20a, 20b can also be checked. Moreover, when the input / output terminal array 20a, 20b has an odd number of input / output terminals 19a, 9b, the central input / output terminals 19aM, 19bM refer to the terminals in the very center of the terminal array; when the input / output terminal array 20a, 20b has an even number of input / output terminals 19a, 9b, the central input / output terminals 19aM, 19bM refer to the two terminals in the very center of the terminal array.

[0101] That is, the input / output terminal arrays 20a and 20b are most easily pressed not only when the liquid crystal driving IC18 or the transparent substrate 12 is pressed in parallel, but also when warping occurs. Therefore, the visual recognition of the indentation is also the easiest to show, thus becoming a benchmark for measuring the uniformity of the pressing of the terminal array.

[0102] Furthermore, if the difference between the average indentation distance of an input / output terminal 19a, 19b and the average indentation distance of the input / output terminals 19aM, 19bM in the center of the input / output terminal array 20a, 20b is within ±30%, then the pressing force applied to the conductive particle 4 in that input / output terminal 19a, 19b will also be approximately the same as that of the input / output terminals 19aM, 19bM in the center of the terminal array. It is assumed that the input / output protrusions 21a, 21b are pressed in parallel, and the deviation of the conduction resistance of the other input / output terminals 19a, 19b is also small. On the other hand, if the difference between the average indentation distance of one input / output terminal 19a, 19b and the average indentation distance of the input / output terminals 19aM, 19bM in the center of the input / output terminal array 20a, 20b exceeds ±30%, it is considered that the input / output protrusions 21a, 21b in that terminal array are not pressed in parallel with the input / output terminals 19a, 19b, and the deviation in the on-resistance between each input / output terminal 19a, 19b is considered large. This deviation in on-resistance also includes the effects of aging during reliability testing, etc.

[0103] Furthermore, in each input / output terminal 19a, 19b of the parallel input / output terminal rows 20a, 20b on the transparent substrate 12, the indentation 30 preferably ensures that the distance between the indentations of the entire indentation 30 within one input / output terminal 19a, 19b is within ±30% of the average distance between indentations, more preferably within 15%, and even more preferably within 7%. Additionally, in the parallel input / output terminal rows 20a, 20b on the transparent substrate 12, the difference between the average distance between indentations within one input / output terminal 19a, 19b and the average distance between indentations in the central input / output terminals 19aM, 19bM of the input / output terminal rows 20a, 20b is preferably within ±30%, more preferably within 15%, and even more preferably within 7%. In this way, by comparing the indentations of the parallel terminal rows, the uniformity of the entire pressing surface area can be checked.

[0104] [Concave / convex parts]

[0105] Here, the input / output bumps 21a and 21b of the liquid crystal driving IC18 can also have uneven portions 28 with a height difference within 50% of the particle size of the conductive particles 4 on the surface that captures the conductive particles 4. For example... Figure 10, Figure 11 As shown, the uneven portion 28 is formed, for example, by protruding from the two side edges or the central portion of the surface that captures the conductive particles 4. In addition, the height difference of the uneven portion 28 is set as the difference between the highest protrusion 28a and the lowest concave portion 28b on the surface of the input and output protrusions 21a and 21b.

[0106] Furthermore, the unevenness of the protrusion 28 is set to within 50% of the particle size of the conductive particles 4 before pressing. By keeping the unevenness within 50% of the particle size of the conductive particles 4, even when the conductive particles 4 are captured by the recess 28b, the conductive particles 4 are also sufficiently pressed into the recess 28b, and the protrusion 28a is not allowed to directly abut against the input / output terminals 19a, 19b. Therefore, the input / output protrusions 21a, 21b and the input / output terminals 19a, 19b are electrically connected by holding the conductive particles 4, ensuring good conductivity reliability even under environmental changes after connection. In addition, by providing the unevenness of the protrusion 28 with a height difference within 50% of the particle size of the conductive particles 4 on the surface of the input / output protrusions 21a, 21b, the visual recognizability of the indentation in the input / output terminals 19a, 19b is not particularly affected, ensuring good visual recognizability.

[0107] On the other hand, if the height difference of the uneven part 28 exceeds 50% of the particle size of the conductive particles 4 before pressing, then... Figure 12 , Figure 13 As shown, when the conductive particles 4 are captured by the recess 28b, the pressure of the conductive particles 4 may be insufficient, leading to an increase in on-resistance. Furthermore, because the protrusion 28a directly abuts against the input / output terminals 19a and 19b, the tracking accuracy for changes in the distance between the connected input / output protrusions 21a and 21b and the input / output terminals 19a and 19b is lower, potentially compromising on-resistance. Additionally, regarding... Figure 12 The conductive particles 4, as an example of the case where the recesses 28b of the input / output bumps 21a and 21b are used to fill the gaps, are also shown to be embedded in the recesses 28b. Due to material variations in the input / output bumps 21a and 21b, hardness variations occur, causing the conductive particles 4 to become embedded in the input / output bumps 21a and 21b during the crimping process. In this case, the tracking ability for changes in the distance between the connected input / output bumps 21a and 21b and the input / output terminals 19a and 19b becomes lower, which could potentially compromise the reliability of the conductive connection. Example

[0108] [First Embodiment]

[0109] Next, the first embodiment of the present invention will be described. In the first embodiment, an anisotropic conductive film with regularly arranged conductive particles and an anisotropic conductive film with randomly dispersed conductive particles were used to make a connector sample for connecting an evaluation IC to an evaluation glass substrate. The number and independence of indentations appearing on the terminals of the evaluation glass substrate were evaluated, and the initial on-resistance and the short-circuit occurrence rate between adjacent IC bumps were measured.

[0110] [Anisotropic conductive film]

[0111] The adhesive resin layer of the anisotropic conductive film used for IC interconnection was evaluated by adjusting the adhesive resin composition by adding 60 parts by weight of phenoxy resin (trade name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.), 40 parts by weight of epoxy resin (trade name: jER828, manufactured by Mitsubishi Chemical Co., Ltd.), and 2 parts by weight of cationic curing agent (trade name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.) to a solvent, and then applying the adhesive resin composition to a release film and firing it.

[0112] [Evaluation IC for on-resistance measurement]

[0113] As an evaluation element for measuring on-resistance, an evaluation IC with the following dimensions was used: 0.7mm × 20mm, thickness 0.2mm; and Au-plated bumps with a width of 15μm × length of 100μm and a height of 12μm.

[0114] [Evaluation IC for short-circuit testing between IC bumps]

[0115] As an evaluation element for determining short circuits between IC bumps, an evaluation IC with the following dimensions was used: 0.7mm × 20mm, thickness 0.2mm; bumps (Au-plated): width 15μm × length 100μm, height 12μm; and space width between bumps: 7.5μm.

[0116] [Evaluation glass substrate]

[0117] As an evaluation glass substrate that connects an evaluation IC for measuring on-resistance and an evaluation IC for measuring short circuits between IC bumps, an ITO patterned glass with a shape of 30mm×50mm and a thickness of 0.5mm is used, which forms a terminal row with multiple terminals of the same size and spacing as the bumps of the evaluation IC for measuring on-resistance.

[0118] After temporarily attaching an anisotropic conductive film to the evaluation glass substrate, the evaluation IC was mounted while aligning the IC bumps with the substrate electrodes. A thermoforming process was then performed using a thermoforming connector at 180°C, 80 MPa, and 5 seconds to create a connector sample. For each connector sample, the number and independence of indentations appearing on the terminals of the evaluation glass substrate, the initial on-resistance, and the short-circuit occurrence rate between adjacent IC bumps were measured.

[0119] Regarding the independence of indentations appearing on the terminals of the evaluation glass substrate, for each connector sample connected to the evaluation IC used for on-resistance measurement, the number of non-independent indentations was measured when multiple indentations appeared as observed from the back of the evaluation glass substrate, with a count of 1000 indentations.

[0120] In addition, the number of indentations appearing in one terminal on the evaluation glass substrate was counted by visual inspection and by processing the photographic images with an image processing machine (WinRoof: Mitani Corporation), and the average of 50 substrate electrodes was calculated.

[0121] Additionally, to confirm whether the IC used for evaluation is being pressed evenly, such as... Figure 9 As shown, for two output terminal rows 20b, the output terminal 19bM in the center of the outer output terminal row 20b, the output terminals 19bMs adjacent to the central output terminal 19bM, the output terminals 19bL and 19bR at both ends, and the output terminals 19bLs and 19bRs adjacent to the output terminals 19bL and 19bR at both ends are evaluated to determine whether more than 75% of the indentations appearing in each terminal are independent. If the terminal 19bM in the center of the row and the terminals 19bL and 19bR at both ends of the row are pressed in the same way, it can be considered that the other terminals in the same row are also pressed in approximately the same way. In addition, if the terminal 19bMs adjacent to the terminal 19bM in the center of the row and the terminals 19bLs and 19bRs adjacent to the terminals at both ends of the row are pressed in the same way, it can be evaluated that the uniformity is higher. This is an example of a simple inspection method.

[0122] Furthermore, the number of output terminals in the outer output terminal row 20b is even. Measurements are taken of the two output terminals in the center of the electrode row. The observation areas of the terminals at both ends of the electrode row, the terminals adjacent to the terminals at both ends, and the terminals adjacent to the central terminal are the same.

[0123] In addition, the on-resistance was measured after initial connection and reliability tests. An initial on-resistance of 1.0Ω or less and an on-resistance of 6Ω or less after reliability tests were considered good. The reliability test conditions were 85°C, 85%RH, and 500hr. Furthermore, regarding the short-circuit incidence rate between IC bumps, a rate of 50ppm or less was considered good.

[0124] [Example 1]

[0125] In Example 1, an anisotropic conductive film with conductive particles regularly arranged in an adhesive resin layer was used. The anisotropic conductive film used in Example 1 was manufactured by laminating an adhesive resin layer onto a stretchable sheet after coating it with an adhesive and uniformly arranging conductive particles in a grid pattern in a single layer thereon, stretching the sheet to the desired elongation ratio. The conductive particles used (trade name: AUL704, manufactured by Sekisui Chemicals Co., Ltd.) had a particle size of 4 μm, an inter-particle distance of 0.5 μm before bonding, and a particle number density of 28,000 particles / mm. 2 .

[0126] [Example 2]

[0127] In Example 2, the interparticle distance before connection was 1 μm and the particle number density was 16,000 particles / mm. 2 In addition to the anisotropic conductive film, the same conditions as in Example 1 were used.

[0128] [Example 3]

[0129] In Example 3, the interparticle distance before connection was 1.5 μm and the particle number density was 10,500 particles / mm. 2 In addition to the anisotropic conductive film, the same conditions as in Example 1 were used.

[0130] [Example 4]

[0131] In Example 4, the interparticle distance before connection was 3 μm and the particle number density was 5200 particles / mm. 2 In addition to the anisotropic conductive film, the same conditions as in Example 1 were used.

[0132] [Example 5]

[0133] In Example 5, conductive particles with a particle size of 3 μm (trade name: AUL703, manufactured by Sekisui Chemicals Co., Ltd.), a particle spacing of 0.5 μm before connection, and a particle number density of 50,000 particles / mm were used. 2 In addition to the anisotropic conductive film, the same conditions as in Example 1 were used.

[0134] [Comparative Example 1]

[0135] In Comparative Example 1, an anisotropic conductive film was prepared by adding conductive particles to an adhesive resin composition, coating it onto a release film, and firing it, thereby randomly dispersing the conductive particles in the adhesive resin layer. The conductive particles used (trade name: AUL704, manufactured by Sekisui Chemicals Co., Ltd.) had a particle size of 4 μm and a particle number density of 100,000 particles / mm². 2 .

[0136] [Comparative Example 2]

[0137] In Comparative Example 2, the particle number density was 60,000 particles / mm². 2 Except for that, the same conditions as in Comparative Example 1 were used.

[0138] [Table 1]

[0139] .

[0140] As shown in Table 1, in the connector samples of Comparative Examples 1 and 2, within 1000 indentations, at least 10% of the indentations were adjacent or repeated, with 104 (Comparative Example 1) and 232 (Comparative Example 2) being adjacent or repeated, indicating poor visual recognition. On the other hand, in the connector samples of Examples 1-5, there were two fewer adjacent or repeated indentations than in the comparative examples, thus indicating good visual recognition. Furthermore, both the examples and the comparative examples showed a tendency for the independence of the indentations to deteriorate proportionally to the number density of conductive particles.

[0141] Furthermore, when comparing the number of indentations within a single terminal using visual inspection and image processing, the differences are larger in the comparative examples and smaller in the embodiments. This is believed to be because the comparative examples have fewer indentations due to their adjacency or repetition, leading to multiple indentations being counted as one, resulting in poor identification. On the other hand, in the embodiments, the indentations are almost never adjacent or repetitive, so no difference is observed visually or with the image processing. Therefore, it can be concluded that the identification of each indentation is easy and accurate.

[0142] Furthermore, regarding whether 75% or more of the indentations appearing in each terminal of the terminal row, the terminal adjacent to the central terminal, the terminals at both ends, and the terminals adjacent to the terminals at both ends are independent, the comparative example failed to obtain a state in which 75% or more of the indentations are independent in any type of terminal that is easily identifiable, while in the embodiment, a state in which 75% or more of the indentations are independent in all terminals that is easily identifiable is obtained.

[0143] The connector samples involved in these embodiments have an initial on-resistance and an on-resistance after reliability testing of less than 1Ω. In addition, the occurrence rate of short circuits between IC bumps is less than 50ppm. That is, by examining the indentations in 4 to 8 terminals provided in the center and both ends of the terminal array according to the connector samples involved in the embodiments, the uniformity of the pressing in the terminal array can be confirmed.

[0144] Furthermore, in the connector samples involved in each embodiment, the same observation was made on the terminal row (input terminal row 20a) formed on the side edge opposite to the side edge of the substrate forming the terminal row for observing the indentation, which is parallel to the terminal row for observing the indentation. Similarly, more than 75% of the indentations appearing in each terminal of the terminal row, the terminal adjacent to the central terminal, the terminals at both ends, and the terminals adjacent to the terminals at both ends, are independent. That is, it can be seen that the connector samples involved in each embodiment can obtain uniformity of pressing throughout the entire area of ​​the pressing part of the IC for evaluation.

[0145] [Second Embodiment]

[0146] Next, a second embodiment of the present invention will be described. In the second embodiment, an anisotropic conductive film with regularly arranged conductive particles and an anisotropic conductive film with randomly dispersed conductive particles were used. An evaluation IC with uneven surfaces having a height difference within 50% of the particle size of the conductive particles was formed on the bump surface to make a connector sample. The number and independence of indentations appearing on the terminals of the evaluation glass substrate were evaluated, and the on-resistance and short-circuit occurrence rate between adjacent IC bumps were measured after initial and reliability tests.

[0147] The evaluation IC used in the second embodiment is the same as that used in the first embodiment, except that the bumps used for on-resistance measurement and short-circuit measurement between IC bumps have uneven portions with a height difference within 50% of the particle size of conductive particles formed on the surface of the input and output bumps. Furthermore, the anisotropic conductive film and the evaluation glass substrate are the same as those used in the first embodiment.

[0148] Furthermore, the number of indentations appearing on the terminals of the evaluation glass substrate, the evaluation location of independence, and the evaluation criteria are the same as in the first embodiment. In addition, in the second embodiment, the number of indentations appearing within one terminal of the evaluation glass substrate is counted visually. Furthermore, the evaluation criteria for on-resistance and short-circuit occurrence rate between IC bumps, as well as the conditions for reliability testing, are the same as in the first embodiment.

[0149] [Examples 6-10]

[0150] Example 6 uses the anisotropic conductive film used in Example 1, Example 7 uses the anisotropic conductive film used in Example 2, Example 8 uses the anisotropic conductive film used in Example 3, Example 9 uses the anisotropic conductive film used in Example 4, and Example 10 uses the anisotropic conductive film used in Example 5.

[0151] [Compare Examples 3 and 4]

[0152] In addition, the anisotropic conductive film used in Comparative Example 1 was used in Comparative Example 3, and the anisotropic conductive film used in Comparative Example 2 was used in Comparative Example 4.

[0153] [Table 2]

[0154] .

[0155] As shown in Table 2, in the case of the evaluation IC using a raised surface to form a surface with a height difference of less than 50% of the particle size of conductive particles, the same tendency as in the first embodiment also occurs. That is, in the connector samples involved in Comparative Examples 3 and 4, within 1000 indentations, at least 10% or more of the indentations are adjacent or repeated, such as 121 (Comparative Example 3) and 265 (Comparative Example 4), which can be said to have poor visual recognition. On the other hand, in the connector samples involved in Examples 6 to 10, there are more than one fewer adjacent or repeated indentation than in each of the comparative examples, so the visual recognition can be said to be good. Furthermore, both the examples and the comparative examples tend to show that the independence of the indentation deteriorates proportionally to the number density of conductive particles.

[0156] Furthermore, regarding whether 75% or more of the indentations appearing in each terminal of the terminal row, the terminal adjacent to the central terminal, the terminals at both ends, and the terminals adjacent to the terminals at both ends are independent, the comparative example failed to obtain a state in which 75% or more of the indentations are independent in any type of terminal that is easily identifiable, while in the embodiment, a state in which 75% or more of the indentations are independent in all terminals that is easily identifiable is obtained.

[0157] The connector samples involved in these embodiments have an initial on-resistance and an on-resistance after reliability testing of less than 1Ω. In addition, the occurrence rate of short circuits between IC bumps is less than 50ppm. That is, by examining the indentations in 4 to 8 terminals provided in the center and both ends of the terminal array according to the connector samples involved in the embodiments, the uniformity of the pressing in the terminal array can be confirmed.

[0158] Furthermore, compared to Comparative Example 2 in Table 1, Comparative Example 4 shares the same characteristic of randomly dispersed conductive particles in the adhesive resin, but the short-circuit incidence rate between IC bumps is significantly different. This indicates that when the conductive particles are randomly distributed, the short-circuit incidence rate between IC bumps deviates due to the non-uniformity of the conductive particles. In other words, it also shows that because the conductive particles are regularly arranged, the short-circuit incidence rate between IC bumps can be suppressed.

[0159] Furthermore, in the connector samples involved in each embodiment, the same observation was made on the terminal row (input terminal row 20a) formed on the side edge opposite to the side edge of the substrate forming the terminal row for observing the indentation, which is parallel to the terminal row for observing the indentation. Similarly, more than 75% of the indentations appearing in each terminal of the terminal row, the terminal adjacent to the central terminal, the terminals at both ends, and the terminals adjacent to the terminals at both ends, are independent. That is, it can be seen that the connector samples involved in each embodiment can obtain uniformity of pressing throughout the entire area of ​​the pressing part of the IC for evaluation.

[0160] Label Explanation

[0161] 1 Anisotropic conductive film; 2 Release film; 3 Adhesive resin layer; 4 Conductive particles; 6 Winding shaft; 10 Liquid crystal display panel; 11, 12 Transparent substrate; 12a Edge portion; 13 Sealing material; 14 Liquid crystal; 15 Panel display portion; 16, 17 Transparent electrodes; 18 Liquid crystal driver IC; 18a Mounting surface; 19a Input terminal; 19b Output terminal; 20a Input terminal array; 20b Output terminal array; 21a Input bump; 21b Output bump; 22a Input bump array; 22b Output bump array; 23 Inter-terminal space; 27 Mounting portion; 31 Substrate-side alignment mark; 32 IC-side alignment mark; 23 Inter-terminal space; 33 Thermo-press connector.

Claims

1. An inspection method for visually inspecting the connection status of an electronic component connected to a transparent substrate via an anisotropic conductive adhesive having arranged conductive particles, wherein the above inspection method, By visually inspecting or comparing the indentations and surrounding areas of the conductive particles contained in the anisotropic conductive adhesive at multiple terminals of the aforementioned transparent substrate, the curves forming the indentations are identified, thereby checking the connection status. The aforementioned indentations do not repeat within the multiple terminals of the aforementioned transparent substrate, but appear in their own independent and regular states. This includes a step of visually or by photographic imagery to determine whether the arrangement of the indentations between adjacent terminals is the same or similar, and repeating this step to gain a grasp of the entire area of ​​the pressing surface.

2. The inspection method as described in claim 1, wherein, The aforementioned transparent substrate has a terminal array in which the aforementioned terminals are arranged. Inspect the indentation inside the terminal in the center of the above terminal row.

3. The inspection method as described in claim 1, wherein, The aforementioned transparent substrate has a terminal array in which the aforementioned terminals are arranged. Inspect the indentations inside the terminals at both ends of the aforementioned terminal row.

4. The inspection method as described in claim 1, wherein, The aforementioned transparent substrate has a terminal array in which the aforementioned terminals are arranged. Inspect the indentations inside the terminals adjacent to the central terminal in the aforementioned terminal row.

5. The inspection method as described in claim 1, wherein, The aforementioned transparent substrate has a terminal array in which the aforementioned terminals are arranged. Inspect the indentations inside the terminals adjacent to the terminals at both ends of the above terminal row.

6. The inspection method as described in claim 1, wherein, More than 55% of the indentations within a single terminal exist independently.

7. The inspection method as described in claim 1, wherein, The difference in distance between the outer edge of the indentation within the aforementioned terminal and the outer edge of the nearest other indentation is within ±30% of the average distance within the same terminal.

8. A method for manufacturing a connector, comprising mounting electronic components on a transparent substrate using an adhesive containing conductive particles. In the method for manufacturing the connector, the electronic component is pressed against the transparent substrate, and the adhesive is hardened to connect the electronic component to the transparent substrate. The above-mentioned adhesive contains conductive particles arranged in the adhesive resin. The manufacturing method of the connector includes the following steps: identifying the curves forming the indentations by visually inspecting or comparing the indentations and their surrounding areas on multiple terminals of the transparent substrate using the adhesive, thereby inspecting the connection status between the electronic component and the transparent substrate through visual inspection. This step includes determining whether the arrangement of the indentations between adjacent terminals is the same or similar by visual inspection or video imaging, and repeating this step to understand the entire area of ​​the pressed surface. The aforementioned indentations do not repeat within the multiple terminals of the aforementioned transparent substrate, and appear in their own independent states.

9. A connector manufactured by the connector manufacturing method of claim 8, the connector comprising: Transparent substrate; and Electronic components are attached to the aforementioned transparent substrate via anisotropic conductive adhesive. At multiple terminals of the aforementioned transparent substrate, the multiple indentations caused by the conductive particles contained in the aforementioned anisotropic conductive adhesive are arranged in the in-plane direction. The aforementioned indentations do not repeat within the multiple terminals of the transparent substrate, appearing in their own independent and regular states, and possessing the visual recognizability that the curve forming the indentation can be identified by comparing it visually or through a photographic image with the surrounding area of ​​the indentation, thereby enabling the inspection of the connection status between the electronic component and the transparent substrate. The aforementioned transparent substrate has a terminal row in which the aforementioned terminals are arranged, and the aforementioned indentation has the same visual recognizability in all terminals within the aforementioned terminal row.

10. The connector as claimed in claim 9, wherein, The aforementioned indentations include more than 40% of the curves when they are set to circular.

11. The connector as claimed in claim 9 or 10, wherein, It possesses visual recognition capabilities that enable the aforementioned checks to be performed visually.

Images