JP6679320B2 - Connection body manufacturing method, electronic component connection method - Google Patents

Description

The present invention is a method for manufacturing a connecting body in which electronic components are connected to a transparent substrate via a circuit connecting adhesive containing a photopolymerization initiator, and a circuit connecting adhesive containing a photopolymerization initiator. about the connection methods to connect the electronic components on a transparent substrate.

  2. Description of the Related Art Conventionally, liquid crystal display devices have been widely used as various display means for televisions, PC monitors, mobile phones, portable game machines, tablet PCs, in-vehicle monitors and the like. In recent years, in such a liquid crystal display device, a so-called COG (chip on glass) in which a liquid crystal drive IC is directly mounted on a substrate of a liquid crystal display panel, or a liquid crystal drive circuit is used from the viewpoint of fine pitch, light weight and thinness. A so-called FOG (film on glass) is used in which a flexible substrate on which is formed is directly mounted on a substrate of a liquid crystal display panel.

  For example, as shown in FIG. 14, the liquid crystal display device 100 adopting the COG mounting method has a liquid crystal display panel 104 that performs a main function for liquid crystal display. The liquid crystal display panel 104 includes a glass substrate or the like. It has two transparent substrates 102 and 103 facing each other. In the liquid crystal display panel 104, the transparent substrates 102 and 103 are attached to each other by a frame-shaped seal 105, and the liquid crystal 106 is enclosed in a space surrounded by the transparent substrates 102 and 103 and the seal 105. A panel display unit 107 is provided.

  The transparent substrates 102 and 103 have a pair of striped transparent electrodes 108 and 109 made of ITO (indium tin oxide) or the like formed on both inner surfaces facing each other so as to intersect each other. Then, on both transparent substrates 102 and 103, a pixel as a minimum unit of liquid crystal display is configured by the intersection of these transparent electrodes 108 and 109.

  One of the transparent substrates 102 and 103 has a larger planar size than the other transparent substrate 102, and the transparent electrode 109 is provided on the edge 103a of the large transparent substrate 103. Terminal portion 109a is formed. Alignment films 111 and 112 that have been subjected to a predetermined rubbing treatment are formed on both transparent electrodes 108 and 109, and the alignment films 111 and 112 regulate the initial alignment of liquid crystal molecules. ing. Further, a pair of polarizing plates 118 and 119 is arranged outside the transparent electrodes 108 and 109, and the polarizing directions of the polarizing plates 118 and 119 regulate the vibration direction of transmitted light from a light source 120 such as a backlight. It is supposed to be done.

  A liquid crystal driving IC 115 is thermocompression-bonded onto the terminal portion 109a via an anisotropic conductive film 114. The anisotropic conductive film 114 is formed by mixing conductive particles in a thermosetting binder resin to form a film. The anisotropic conductive film 114 is heated and pressure-bonded between two conductors so that the conductive particles allow electrical conduction between the conductors. The binder resin holds the mechanical connection between the conductors. The liquid crystal driving IC 115 can selectively change the orientation of the liquid crystal by selectively applying a liquid crystal driving voltage to the pixels to perform a predetermined liquid crystal display. As the adhesive forming the anisotropic conductive film 114, usually, the most reliable thermosetting adhesive is used.

  When connecting the liquid crystal driving IC 115 to the terminal portion 109a through the anisotropic conductive film 114, first, the anisotropic conductive film 114 is provided on the terminal portion 109a of the transparent electrode 109 by a temporary pressure bonding means (not shown). Temporarily crimp. Subsequently, after the liquid crystal driving IC 115 is placed on the anisotropic conductive film 114, the liquid crystal driving IC 115 together with the anisotropic conductive film 114 is connected to the terminals by the thermocompression bonding means 121 such as a thermocompression bonding head as shown in FIG. The thermocompression bonding means 121 is caused to generate heat while being pressed toward the portion 109a. The heat generated by the thermocompression bonding means 121 causes a thermosetting reaction in the anisotropic conductive film 114, whereby the liquid crystal driving IC 115 is bonded onto the terminal portion 109a via the anisotropic conductive film 114.

  However, in the connection method using such an anisotropic conductive film, the heat and pressure temperature is high, and the thermal shock to the electronic components such as the liquid crystal driving IC 115 and the transparent substrate 103 becomes large. In addition, after the anisotropic conductive film is connected, when the temperature drops to room temperature, the binder may shrink due to the temperature difference, and the terminal portion 109a of the transparent substrate 103 may warp. Therefore, problems such as display unevenness and poor connection of the liquid crystal driving IC 115 may occur.

  In Patent Document 2, in a method of bonding a connection target object and a connection target object via a photo-curable adhesive, light irradiation is performed after thermal compression by a heating pressure head is started. Has been described.

JP, 2008-252098, A JP 2012-253288A

  Therefore, a connection method using an ultraviolet curable adhesive instead of the anisotropic conductive film 114 using such a thermosetting adhesive has been proposed. In the connection method using the ultraviolet curable adhesive, the adhesive softens and flows by heat and reaches a temperature sufficient to capture the conductive particles between the terminal portion 109a of the transparent electrode 109 and the electrode of the liquid crystal driving IC 115. Only heat and cure the adhesive by UV irradiation.

  In the connection method using such an ultraviolet curable adhesive, it is not necessary to apply high heat to cure the binder resin, and it is possible to prevent problems due to thermal shock to the liquid crystal driving IC 115 and the transparent substrate 103. In order to perform low-temperature connection using such an ultraviolet curable adhesive, it is necessary to reduce the viscosity itself of the binder resin of the ultraviolet curable anisotropic conductive film.

  However, when the viscosity of the binder resin is reduced, an alignment shift occurs when electronic components such as the liquid crystal driving IC 115 are mounted and pressed by the thermocompression bonding means 112, or when the thermocompression bonding means 112 separates from the liquid crystal driving IC 115. I am afraid to do so. Further, in the COG connection and the like, the fine pitch is advanced and the distance between the terminals is narrowed. Therefore, the misalignment is caused by the electrode terminal of the liquid crystal driving IC 115 and the terminal portion of the transparent substrate 103 connected to the electrode terminal. The pitch with the terminal portion adjacent to 109a may be narrowed, which may cause a short circuit between terminals that short-circuits via the conductive particles.

  Further, when an electronic component having a relatively low rigidity such as the flexible substrate 21 is connected to the transparent substrate 12 by using the anisotropic conductive film 1, as in the technique described in Patent Document 2, bonding is performed by the heat of the pressing head. When pressure is applied in a state where the viscosity of the agent is sufficiently lowered, the stress remains due to bending between the terminals 21a of the flexible substrate 21 indicated by the arrow in FIG. 16 during pressure bonding. In the flexible substrate 21, the residual stress of the flexible substrate 21 is released when the heating and pressing head 30 is separated (at the time of press-out), and as shown in FIG. 17, the residual stress of the flexible substrate 21 causes a pressing direction between the terminals 21a. And the force to return to the opposite direction works. Then, when the residual stress of the flexible substrate 21 is released, as shown in FIG. 18, the terminals 21 a of the flexible substrate 21 are separated at the interface between the binder resin layer 3 of the anisotropic conductive film and the flexible substrate 21 ( The gap 44) is likely to occur. Such peeling may lead to poor connection such as a decrease in conduction resistance value of the connection body and a decrease in adhesive force between the anisotropic conductive film and the adherend.

  For example, for the anisotropic conductive film for FOG, it is desirable to use a soft binder resin that spreads sufficiently during pressure bonding, that is, a binder resin having a low viscosity, in order to secure adhesive strength. However, if the viscosity of the binder resin is excessively reduced, the flexible substrate between the wirings is more likely to bend during pressure bonding, and as a result, the effect of releasing the residual stress of the flexible substrate tends to become more prominent.

The present invention is to solve the above-mentioned problems and to connect electronic components at low temperature by using a photo-curable adhesive, prevent misalignment of electronic components, and improve connection failure. the method of manufacturing, and to provide a connection methods of the electronic components.

  In order to solve the above-mentioned problems, the method for producing a connector according to the present invention is an adhesive disposing step of providing a circuit connecting adhesive containing a photopolymerization initiator on a transparent substrate, and the circuit connecting adhesive. An electronic component is arranged on the transparent substrate via the light irradiation step of irradiating the adhesive for circuit connection with light, and heating and light irradiation while pressing the electronic component against the transparent substrate. The main irradiation step is performed, and the irradiation amount of light in the light irradiation step is smaller than the irradiation amount of light in the main pressing step.

  Further, the method for producing a connected body according to the present invention comprises an adhesive disposing step of providing a circuit connecting adhesive containing a photopolymerization initiator on a transparent substrate, and a transparent substrate on the transparent substrate via the circuit connecting adhesive. An electronic component is placed on the transparent substrate, the electronic component is pressed against the transparent substrate, and a temporary pressure bonding step of irradiating the adhesive for circuit connection with light, while pressing the electronic component against the transparent substrate, The main pressure bonding step of heating and light irradiation is performed, and the light irradiation amount in the temporary pressure bonding step is smaller than the light irradiation amount in the main pressure bonding step.

  Further, the method for connecting electronic components according to the present invention includes an adhesive disposing step of providing an adhesive for circuit connection containing a photopolymerization initiator on a transparent substrate, and an adhesive arranging step on the transparent substrate via the adhesive for circuit connection. And a light irradiation step of irradiating the circuit connecting adhesive with light, and a main pressure bonding step of heating and light irradiation while pressing the electronic component against the transparent substrate. However, the light irradiation amount in the light irradiation step is smaller than the light irradiation amount in the main pressure bonding step.

  According to the present invention, curing is started by irradiating a circuit connecting adhesive containing a photopolymerization initiator with light at an appropriate irradiation amount, and temporary pressure bonding of electronic components is performed in a state where the viscosity is increased. You can Therefore, in the light irradiation step (temporary crimping step) or the main crimping step, when the electronic component is pressed by the crimping tool or when the crimping tool is separated from the electronic component, the electronic component is displaced from the predetermined position, misalignment occurs. Can be suppressed.

FIG. 1 is a sectional view showing a mounting process to which the present invention is applied. FIG. 2 is a cross-sectional view showing the anisotropic conductive film. FIG. 3 is a cross-sectional view showing a step of temporarily attaching the anisotropic conductive film. FIG. 4 is a cross-sectional view showing a step of disposing the liquid crystal driving IC on the transparent substrate. FIG. 5 is a cross-sectional view showing a temporary pressure bonding step of the liquid crystal driving IC. FIG. 6 is a cross-sectional view showing a main pressure bonding step of the liquid crystal driving IC. FIG. 7 is a cross-sectional view showing a connection body in which a liquid crystal driving IC is connected on a transparent substrate. FIG. 8: is sectional drawing which shows an example of the process of arrange | positioning a flexible substrate on a transparent substrate via an anisotropic conductive film. FIG. 9 is a cross-sectional view showing an example of a step of irradiating the anisotropic conductive film with ultraviolet rays after disposing the flexible substrate on the transparent substrate via the anisotropic conductive film. FIG. 10: is sectional drawing which shows an example of the main pressure bonding process of a flexible substrate. FIG. 11 is a diagram for explaining a method of measuring conduction resistance according to the example and the comparative example. FIG. 12 is a diagram for explaining a method for measuring the amount of misalignment in the width direction of the terminals of the connected body sample. FIG. 13 is a diagram for explaining the light irradiation before the main pressure bonding and the timing of the light irradiation and the thermal pressurization during the main pressure bonding in the second embodiment. FIG. 14 is a sectional view showing a conventional liquid crystal display panel. FIG. 15 is a sectional view showing a COG mounting process of a conventional liquid crystal display panel. FIG. 16: is sectional drawing which shows an example of the heating press process of a laminated body in the manufacturing method of the conventional flexible substrate. FIG. 17 is a cross-sectional view showing an example of a laminated body in a state where stress is released at the time of press-out of a heating tool in a conventional method of manufacturing a flexible substrate. FIG. 18 is a cross-sectional view showing an example of a laminated body in a state where residual stress is released in the flexible substrate in the conventional method for manufacturing a flexible substrate.

Hereinafter, a manufacturing method of the present invention has been applied connecting member, about the connection methods of the electronic components 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 various modifications can of course be made without departing from the scope of the present invention. Also, the drawings are schematic, and the ratios of the respective dimensions may differ from the actual ones. Specific dimensions should be judged in consideration of the following description. Further, it is needless to say that the drawings include parts in which dimensional relationships and ratios are different from each other.

<First Embodiment>
In the following first embodiment, a case where so-called COG (chip on glass) mounting, in which an IC chip for driving a liquid crystal is mounted as an electronic component, is mounted on a glass substrate of a liquid crystal display panel will be described as an example. In this liquid crystal display panel 10, as shown in FIG. 1, two transparent substrates 11 and 12 made of glass substrates or the like are arranged opposite to each other, and these transparent substrates 11 and 12 are attached to each other by a frame-shaped seal 13. . The liquid crystal display panel 10 has a panel display unit 15 formed by enclosing the liquid crystal 14 in the space surrounded by the transparent substrates 11 and 12.

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

  One of the transparent substrates 11 and 12 has a larger planar size than the other transparent substrate 11, and the edge 12a of the larger transparent substrate 12 is used as an electronic component. A COG mounting portion 20 on which the liquid crystal driving IC 18 is mounted is provided, and a FOG mounting portion 22 on which a flexible substrate 21 having a liquid crystal driving circuit as an electronic component is mounted is provided near the outside of the COG mounting portion 20. Has been.

  Note that the liquid crystal driving IC and the liquid crystal driving circuit can perform a predetermined liquid crystal display by selectively changing the orientation of the liquid crystal by selectively applying the liquid crystal driving voltage to the pixels. ing.

  A terminal portion 17 a of the transparent electrode 17 is formed on each of the mounting portions 20 and 22. On the terminal portion 17a, the liquid crystal driving IC 18 and the flexible substrate 21 are connected by using the anisotropic conductive film 1 as a circuit connecting adhesive containing a photopolymerization initiator. The anisotropic conductive film 1 contains the conductive particles 4, and the electrodes of the liquid crystal driving IC 18 and the flexible substrate 21 and the terminal portion 17a of the transparent electrode 17 formed on the edge portion 12a of the transparent substrate 12, It is electrically connected via the conductive particles 4. The anisotropic conductive film 1 is an ultraviolet curable adhesive, and is fluidized by being thermocompression-bonded by a heating and pressing head 30 to be described later, so that the conductive particles 4 are brought into contact with the terminal portion 17a, the liquid crystal driving IC 18, and the flexible substrate. The conductive particles 4 are crushed between the electrodes 21 and are irradiated with ultraviolet rays by the ultraviolet irradiator 31, so that the conductive particles 4 are cured in the crushed state. As a result, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 to the liquid crystal driving IC 18 and the flexible substrate 21.

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

[Anisotropic conductive film]
As shown in FIG. 2, an anisotropic conductive film (ACF: Anisotropic Conductive Film) 1 usually has a binder resin layer (adhesive layer) 3 containing conductive particles formed on a release film 2 serving as a base material. It was done. In the anisotropic conductive film 1, as shown in FIG. 1, the binder resin layer 3 is interposed between the transparent electrode 17 formed on the transparent substrate 12 of the liquid crystal display panel 10 and the liquid crystal driving IC 18 or the flexible substrate 21. Thus, the liquid crystal display panel 10 and the liquid crystal driving IC 18 or the flexible substrate 21 are connected to each other and electrically connected.

  As the release film 2, a base material generally used in anisotropic conductive films, such as polyethylene terephthalate film, can be used.

  The binder resin layer 3 is composed of conductive particles 4 dispersed in a binder. The binder contains a film-forming resin, a curable resin, a curing agent, a silane coupling agent, and the like, and is the same as the binder used in a usual anisotropic conductive film.

  As the film forming resin, 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 phenoxy resin, epoxy resin, modified epoxy resin, urethane resin and the like. Among them, a phenoxy resin is particularly preferable from the viewpoint of film formation state, connection reliability, and the like.

  The curable resin is not particularly limited, and examples thereof include epoxy resin and acrylic resin.

  The epoxy resin is not particularly limited and can be appropriately selected depending on the purpose. Specific examples include, for example, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, Examples thereof include dicyclopentadiene type epoxy resin and triphenylmethane type epoxy resin. These may be used alone or in combination of two or more.

  The acrylic resin is not particularly limited and may be appropriately selected depending on the intended purpose. Specific examples include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate. , Trimethylolpropane triacrylate, dimethyloltricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane , 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyi) ) Isocyanurate, urethane acrylate, epoxy acrylate. These may be used alone or in combination of two or more.

  The curing agent is not particularly limited as long as it is a photo-curing type, and can be appropriately selected according to the purpose, but when the curable resin is an epoxy resin, a cationic curing agent is preferable, and an anionic curing agent is preferable. May be. When the curable resin is an acrylic resin, a radical type curing agent is preferable. The curable resin may include an epoxy resin and an acrylic resin, respectively.

  The cationic curing agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include sulfonium salts and onium salts. Of these, aromatic sulfonium salts are preferable. The radical type curing agent is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include organic peroxides.

  Examples of the silane coupling agent include epoxy type, amino type, mercapto sulfide type, and ureide type. By adding the silane coupling agent, the adhesiveness at the interface between the organic material and the inorganic material is improved.

  The conductive particles 4 may be any known conductive particles used in anisotropic conductive films. Examples of the conductive particles 4 include particles of various metals or metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver and gold, metal oxides, carbon, graphite, glass, ceramics, Examples thereof include those obtained by coating the surface of particles of plastic or the like with metal, or those obtained by further coating the surface of these particles with an insulating thin film. When the surface of the resin particles is coated with a metal, examples of the resin particles include epoxy resin, phenol resin, acrylic resin, acrylonitrile styrene (AS) resin, benzoguanamine resin, divinylbenzene resin, styrene resin, etc. Particles can be mentioned.

[Production method]
Next, a manufacturing process of a connection body in which the liquid crystal driving IC 18 and the flexible substrate 21 are connected to the transparent electrode 17 of the transparent substrate 12 through the anisotropic conductive film 1 will be described.

<Specific example 1-1>
[Temporary pasting process]
First, the anisotropic conductive film 1 is temporarily attached on the transparent substrate 12 (adhesive placement step). The method of temporarily attaching the anisotropic conductive film is as shown in FIG. 3, in which the anisotropic conductive film 1 is placed on the transparent electrode 17 of the transparent substrate 12 so that the binder resin layer 3 is on the transparent electrode 17 side. Deploy. After disposing the binder resin layer 3 on the transparent electrode 17, the binder resin layer 3 is heated and pressed from the side of the release film 2 with, for example, a thermocompression bonding tool, the thermocompression bonding tool is separated from the release film 2, and the release film 2 is a binder resin. Peel from layer 3. The anisotropic conductive film 1 may be temporarily attached by pressing with a thermocompression bonding tool and light irradiation, or by using both heat pressing and light irradiation.

[Alignment process / Temporary pressure bonding process]
Next, the liquid crystal driving IC 18 is placed on the transparent substrate 12 via the anisotropic conductive film 1, and the liquid crystal driving IC 18 is pressed against the transparent substrate 12 and the anisotropic conductive film 1 is irradiated with light ( Temporary crimping process). First, as shown in FIG. 4, the liquid crystal driving IC 18 and the transparent electrode 17 are aligned. Specifically, the liquid crystal driving IC is arranged so that each terminal portion 17a of the transparent electrode 17 and the electrode terminal 18a of the liquid crystal driving IC 18 face each other via the binder resin layer 3.

  Next, as shown in FIG. 5, the upper surface of the liquid crystal driving IC 18 is heated at a predetermined temperature by a thermocompression bonding tool 30 via a cushioning material 32 at a lower temperature and a lower pressure than the main bonding step described later. The binder resin layer 3 of the anisotropic conductive film 1 is irradiated with ultraviolet rays by an ultraviolet ray irradiator 31 provided on the back side of the transparent substrate 12 while being thermally pressurized.

  The temperature of the heat and pressure applied by the thermocompression bonding tool 30 is ± 10 to 20 ° C. (for example, around 80 ° C.) with respect to a predetermined temperature indicating the viscosity (minimum melt viscosity) when the binder resin layer is melted before the start of curing Is set to. As a result, the warpage of the transparent substrate is minimized, and the liquid crystal driving IC is not damaged by heat.

  The ultraviolet light emitted from the ultraviolet irradiator 31 passes through the transparent support 12 made of glass or the like that supports the transparent substrate 12 and the transparent substrate 12 supported by this support to irradiate the binder resin layer 3. An LED lamp, a mercury lamp, a metal halide lamp, or the like can be used as the ultraviolet irradiator 31.

Here, the irradiation amount of ultraviolet rays (= UV illuminance (mW / cm ² ) × irradiation time (seconds)) with which the anisotropic conductive film 1 is irradiated in the temporary pressure bonding step is smaller than the light irradiation amount in the main pressure bonding step. It is preferable that the irradiation amount in the main pressure bonding step is 3 to 20%. For example, when the irradiation amount in the main pressure bonding step is 100 mW / cm ² for 1 second, the irradiation amount of ultraviolet rays in the temporary pressure bonding step is preferably 3 to 15 mW / cm ² and 0.5 to 2 seconds.

  In the temporary pressure bonding step, it is preferable to change the light irradiation amount according to the minimum inter-wiring space (minimum inter-bump space) of the liquid crystal driving IC 18. For example, when the minimum inter-wiring space of the liquid crystal driving IC 18 is 8 to 20 μm, the light irradiation amount in the temporary pressure bonding step is preferably 4 to 20% of the light irradiation amount in the main pressure bonding step. Under such light irradiation conditions, it is not necessary to adjust the viscosity of the binder resin of the anisotropic conductive film each time.

  Further, the pressing force to the liquid crystal driving IC 18 in the temporary pressure bonding step is preferably 40 to 90%, and more preferably 70 to 80% of the pressing force to the liquid crystal driving IC 18 in the main pressure bonding step.

  In the temporary pressure-bonding step, the anisotropic conductive film 1 is irradiated with ultraviolet rays at an appropriate dose to start the curing of the binder resin layer 3 and temporarily pressure-bond the liquid crystal driving IC 18 with the viscosity increased. be able to. Therefore, when the liquid crystal driving IC 18 is pressed by the thermocompression bonding tool 30 or when the thermocompression bonding tool 30 is separated from the liquid crystal driving IC 18, the liquid crystal driving IC 18 has a predetermined size in the temporary pressure bonding step and the main pressure bonding step described later. It is possible to suppress the misalignment that deviates from the position.

[Main crimping process]
Next, as shown in FIG. 6, while pressing the liquid crystal driving IC 18 against the transparent substrate 12, pressure and light irradiation are performed to electrically and mechanically connect the liquid crystal driving IC 18 and the transparent substrate 12. (Main pressure bonding step). In the main compression bonding step, the thermocompression bonding tool 30 presses the conductive particles 4 with a predetermined pressure that is sandwiched between the electrode terminal 18a of the liquid crystal driving IC 18 and the terminal portion 17a of the transparent electrode 17. Further, in the main pressure-bonding step, ultraviolet rays are irradiated with the illuminance and the time for curing the binder resin layer 3.

  As a result, the binder resin flows out from between the electrode terminal 18a of the liquid crystal driving IC 18 and the terminal portion 17a of the transparent electrode 17, and the conductive particles 4 are sandwiched so that conduction is achieved. Is cured. As a result, as shown in FIG. 7, the liquid crystal display panel 10 is formed as a connection body in which the liquid crystal driving IC 18 is electrically and mechanically connected to the transparent substrate 12.

  At this time, according to the main manufacturing process, the viscosity of the binder resin is increased to some extent by irradiating the anisotropic conductive film 1 with ultraviolet rays in a dose smaller than the light dose in the main pressure bonding process in the temporary pressure bonding process. Therefore, it is possible to prevent misalignment of the liquid crystal driving IC 18 when the thermocompression bonding tool 30 is pressed or when the thermocompression bonding tool 30 is separated. Therefore, the pitch between the electrode terminal 18a of the liquid crystal driving IC 18 with a fine pitch and the terminal portion adjacent to the terminal portion 17a of the transparent electrode 17 connected to the electrode terminal 18a is narrowed, and the conductive particles 4 are interposed therebetween. It is possible to prevent a short circuit between short-circuited terminals.

  The ultraviolet irradiation may be started from the temporary attaching step. At this time, the illuminance in the temporary bonding step may be lower than that in the temporary pressure bonding step.

<Specific example 1-2>
In the present manufacturing method, in the above-described temporary pressure bonding step, ultraviolet irradiation may be performed from the liquid crystal driving IC 18 side instead of the transparent substrate 12 side.

<Specific example 1-3>
This manufacturing method includes a step of providing the anisotropic conductive film 1 on the transparent substrate 12, a step of disposing the liquid crystal driving IC 18 on the anisotropic conductive film 1, and a step of irradiating light from the liquid crystal driving IC 18 side. (Light irradiation step) and a step of performing heating and light irradiation while pressing the liquid crystal driving IC 18 against the transparent substrate 12 (main pressure bonding step), and the irradiation amount of light in the light irradiation step is main pressure bonding. It may be smaller than the light irradiation amount in the process.

<Specific example 1-4>
The present manufacturing method may further include a step of pressing the liquid crystal driving IC 18 with a heating tool before and after the light irradiation step in Specific Example 1-3.

<Specific example 1-5>
The present manufacturing method is different between the step of providing the anisotropic conductive film 1 on the transparent substrate 12 and the step of disposing the liquid crystal driving IC 18 on the anisotropic conductive film 1 in Specific Example 1-3. It may further have a step of irradiating the entire surface of the anisotropic conductive film 1.

<Specific example 1-6>
This manufacturing method includes a step of providing the anisotropic conductive film 1 on the transparent substrate 12 and a step of irradiating the entire surface of the anisotropic conductive film 1 with light from the anisotropic conductive film 1 side (pre-irradiation step). And a step of disposing the liquid crystal driving IC 18 on the anisotropic conductive film 1 after the pre-irradiation step, a step of performing light irradiation from the transparent substrate 12 side (light irradiation step), and the liquid crystal driving IC 18 on the transparent substrate 12. And a step of performing heating and light irradiation (main pressure bonding step) while pressing against each other, and the total light irradiation amount of the previous irradiation step and the light irradiation step is smaller than the light irradiation amount in the main pressure bonding step. You may do it.

<Second Embodiment>
In the second embodiment, a case where a flexible substrate is mounted (FOG mounting) as an electronic component on a glass substrate of a liquid crystal display panel will be described as an example. In the second embodiment, the same reference numerals as those in the first embodiment are the same as those in the first embodiment.

[Method of manufacturing connected body]
<Specific example 2-1>
The present manufacturing method as an example includes a step of providing an anisotropic conductive film on a transparent substrate, and arranging a flexible substrate on the transparent substrate via the anisotropic conductive film, and irradiating the anisotropic conductive film with light. And a step of performing heating and light irradiation while pressing the flexible substrate against the transparent substrate.

[Temporary pasting process]
The temporary attaching step can be performed in the same manner as the temporary attaching step in the above-described first embodiment.

[Light irradiation process]
In the light irradiation step, for example, as shown in FIG. 8, the flexible substrate 21 is arranged on the transparent substrate 12 via the anisotropic conductive film 1, and the anisotropic conductive film 1 is irradiated with light. For the light irradiation, for example, as shown in FIG. 9, the binder resin layer 3 of the anisotropic conductive film 1 can be irradiated with ultraviolet rays by an ultraviolet ray irradiator 31 arranged on the transparent substrate 12 side. The light irradiation may be performed from the flexible substrate 21 side instead of the transparent substrate 12 side.

  In the light irradiation step, the irradiation amount of the ultraviolet rays with which the anisotropic conductive film 1 is irradiated is made smaller than the irradiation amount of light in the main pressure bonding step described later. In addition, in the light irradiation step, it is preferable to change the light irradiation amount depending on the minimum inter-wiring space of the flexible substrate 21. For example, when the minimum wiring space of the flexible substrate 21 exceeds 25 μm, the light irradiation amount in the light irradiation step is preferably 5 to 25% of the light irradiation amount in the main pressure bonding step, and is 5 to 15%. More preferably. Further, for example, when the minimum wiring space of the flexible substrate 21 is 25 μm or less, the light irradiation amount in the light irradiation step is preferably 2 to 15% of the light irradiation amount in the main pressure bonding step, and It is more preferably set to 10%.

The ultraviolet illuminance and the ultraviolet irradiation time for irradiation in the light irradiation step can be appropriately selected within a range satisfying the above-mentioned conditions. For example, the ultraviolet illuminance can be set to 1 to 400 mW / cm ² , and the ultraviolet irradiation time can be set to 0.5 to 2 seconds. Particularly, from the viewpoint of preventing the anisotropic conductive film 1 from being completely cured before the main pressure bonding step, the light irradiation time in the light irradiation step is ⅕ or less of the pressure bonding time in the main pressure bonding step. It is preferable.

[Main crimping process]
In the final pressure bonding step, as shown in FIG. 10, for example, heating and light irradiation are performed while pressing the flexible substrate 21 against the transparent substrate 17. As a result, the flexible substrate 21 and the transparent substrate 17 are connected to each other, and a liquid crystal display panel is formed, for example, as a connection body in which the flexible substrate 21 is connected to the transparent substrate 17.

  In the main pressure bonding step, first, it is preferable that the flexible substrate 21 and the transparent electrode 17 are aligned. Specifically, the flexible substrate 21 is arranged so that each terminal portion 17a of the transparent electrode 17 and the terminal portion 21a of the flexible substrate 21 face each other with the binder resin layer 3 in between.

  Next, the upper surface of the flexible substrate 21 is thermally pressed by the thermocompression bonding tool 30 heated to a predetermined heating temperature through the buffer material 32, and the ultraviolet irradiation device 31 provided on the back side of the transparent substrate 12 changes the temperature. The binder resin layer 3 of the anisotropic conductive film 1 is irradiated with ultraviolet rays. The thermal pressurization in the main press-bonding step is performed by applying a predetermined pressure for sandwiching the conductive particles 4 between the terminal portion 21a of the flexible substrate 21 and the terminal portion 17a of the transparent electrode 17. The light irradiation in the main pressure bonding step is performed under the condition that the binder resin layer 3 can be cured.

  According to such a method for manufacturing a connector, the light irradiation amount in the light irradiation step is made smaller than the light irradiation amount in the main pressure bonding step, so that the binder of the anisotropic conductive film 1 before the main pressure bonding step. Since the viscosity of the resin is increased to some extent, it is possible to prevent misalignment of the flexible substrate 21 when pressure is applied by the thermocompression bonding tool 30 or when the thermocompression bonding tool 30 is separated.

  Further, according to the present manufacturing method, since it is possible to suppress the influence of releasing the residual stress of the flexible substrate during pressure bonding, it is possible to suppress peeling at the interface between the binder resin layer of the anisotropic conductive film and the flexible substrate. Therefore, it is possible to suppress a connection failure such as a decrease in the conduction resistance value of the connection body and a decrease in the adhesive force between the anisotropic conductive film and the adherend.

  In addition, according to the present manufacturing method, even if the viscosity of the binder resin of the anisotropic conductive film is not adjusted each time according to the wiring layout of the flexible substrate and the space between the wirings, the residual stress can be released depending on the conditions of light irradiation. The influence can be suppressed. Therefore, the manufacturing efficiency of the connected body can be further improved.

  In the light irradiation step described above, the binder resin layer of the anisotropic conductive film 1 is applied by the ultraviolet irradiator 31 while thermocompressing with a thermocompression bonding tool at a lower temperature and a lower pressure than in the main pressure bonding step via a cushioning material. 3 may be irradiated with ultraviolet rays. The heat pressurizing temperature and the pressing force by the thermocompression bonding tool can be set to the same conditions as those in the temporary pressure bonding step in the above-described first embodiment, for example.

<Specific example 2-2>
The present manufacturing method may further include a step of pressing the flexible substrate 21 with a heating tool before and after the light irradiation step in Example 2-1.

<Specific example 2-3>
The present manufacturing method is such that light is applied to the entire surface of the anisotropic conductive film 1 between the step of providing the anisotropic conductive film 1 in Example 2-1 on the transparent substrate 12 and the step of disposing the flexible substrate 21. You may further have the process of performing irradiation.

<Specific example 2-4>
The present manufacturing method includes a temporary attaching step of providing the anisotropic conductive film 1 on the transparent substrate 12, a step of irradiating the entire surface of the anisotropic conductive film 1 with light (pre-irradiation step), and a pre-irradiation step. A step of arranging the flexible substrate 21 on the anisotropic conductive film 1, a step of irradiating light from the transparent substrate 12 side (a light irradiating step), heating the flexible substrate 21 against the transparent substrate 12 while heating and A light irradiation step (main pressure bonding step) may be included, and the total light irradiation amount in the first irradiation step and the light irradiation step may be smaller than the light irradiation amount in the main pressure bonding step.

<First embodiment>
Next, examples of the present technology will be described. In this example, for each connection body sample of a transparent substrate and an IC chip manufactured under different ultraviolet irradiation conditions in the temporary pressure bonding step, the IC chip and the transparent electrode of the transparent substrate after the initial connection and after the reliability test were performed. The conduction resistance value (Ω) and the amount of IC chip alignment deviation (μm) were measured.

  An anisotropic conductive film including a binder resin layer containing a photo-acid generator and a cationically polymerizable compound was prepared as an adhesive used for connection.

This binder resin layer is
Phenoxy resin (YP-50: Nippon Steel & Sumikin Chemical Co., Ltd.); 45 parts by mass of isocyanuric acid EO-modified diacrylate (M-215: Toa Gosei Co., Ltd.); 45 parts by mass of silane coupling agent (KBM-403: Shin-Etsu Chemical). Industrial Co., Ltd.); 2 parts by mass photoradical generator (Irgacure 369: manufactured by BASF Japan Co., Ltd.); 8 parts by mass of ethyl acetate and toluene to prepare a mixed solution having a solid content of 50% and conductivity. Particles (AUL704: average particle diameter 4 μm, manufactured by Sekisui Chemical Co., Ltd.) were dispersed so that the particle density was about 50,000 particles / mm ² . This mixed solution was applied on a PET film having a thickness of 50 μm and dried in an oven at 70 ° C. for 5 minutes to form a film having a thickness of 20 μm.

As an evaluation element,
External shape: 1.8 mm x 20 mm,
Bump height: 15 μm,
Bump size: 30 × 60 μm (minimum space between bumps 10 μm),
The evaluation IC of was used. The bumps are arranged inside both ends of the evaluation IC outer shape in the long side direction such that the short side of the bump is parallel to the evaluation IC outer shape long side direction. The distance between the bumps in this arrangement direction is the minimum inter-bump space of the present evaluation element.

  As the evaluation base material to which the evaluation IC was connected, an ITO-coated glass having a thickness of 0.5 mm was used.

  An evaluation IC is placed on the glass substrate via the anisotropic conductive film, and heat-pressed by a thermocompression-bonding tool and ultraviolet rays are radiated by an ultraviolet ray irradiator (ZUV-C30H: OMRON Corporation) for temporary pressure-bonding and main bonding. Crimping was performed to form a connected body sample.

  The temporary pressure bonding conditions are 80 ° C., 2 MPa, and 2 seconds for each of Examples 1 to 6 and Comparative Examples 1 to 8. At the time of pressing, a Teflon (thickness of 50 μm as a cushioning material between the thermocompression bonding tool and the IC for evaluation ( (Registered trademark) sheet. The ultraviolet irradiation was started at the same time as the heating and pressing by the thermocompression bonding tool. The ultraviolet irradiation during the temporary pressure bonding was performed from the glass substrate side.

The main pressure bonding conditions are 100 ° C., 80 MPa, and 5 seconds in each of Examples 1 to 6 and Comparative Examples 1 to 8. At the time of pressing, a Teflon (thickness of 50 μm as a cushioning material between the thermocompression bonding tool and the evaluation IC ( (Registered trademark) sheet. The ultraviolet irradiation was started 4 seconds after the heating and pressing by the thermocompression bonding tool, the irradiation time was 1 second, and the illuminance was 100 mW / cm ² . Ultraviolet irradiation at the time of main pressure bonding was performed from the glass substrate side.

  Then, the initial conduction resistance value (Ω) and the conduction resistance value (Ω) after the reliability test were measured for the connection body samples according to each example and comparative example. The condition of the reliability test is 85 ° C. 85% RH 500 hr. As shown in FIG. 11, the conduction resistance value was measured when a digital multimeter was connected to the wiring 43 of the ITO coating glass connected to the bump 42 of the evaluation IC and a current of 2 mA was applied by the so-called 4-terminal method. The conduction resistance value was measured.

  Further, with respect to the connected body samples according to each of the examples and the comparative examples, the amount of misalignment was measured using a stereoscopic microscope. The allowable range of the misalignment amount was set to 1.0 μm or less.

[Example 1]
In Example 1, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 3 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 1 is 3% of the irradiation amount in the main pressure bonding step. The connection sample according to Example 1 had a low initial conduction resistance of 1.4Ω and a conduction resistance of 4.3Ω after the reliability test. The amount of misalignment of the connected sample according to Example 1 was 0.9 μm.

[Example 2]
In Example 2, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 5 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 2 is 5% of the irradiation amount in the main pressure bonding step. The connection sample according to Example 2 had a low initial conduction resistance of 1.0Ω and a conduction resistance of 4.1Ω after the reliability test. The amount of misalignment of the connected sample according to Example 2 was 0.7 μm.

[Example 3]
In Example 3, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 15 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 3 is 15% of the irradiation amount in the main pressure bonding step. The connection body sample according to Example 3 had a low initial conduction resistance of 1.2Ω and a conduction resistance of 4.4Ω after the reliability test. The amount of misalignment of the connected sample according to Example 3 was 0.3 μm.

[Example 4]
In Example 4, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 20 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 4 is 20% of the irradiation amount in the main pressure bonding step. The connection sample according to Example 4 had a low initial conduction resistance of 2.4Ω and a conduction resistance of 4.4Ω after the reliability test. The amount of misalignment of the connected sample according to Example 4 was 0.3 μm.

[Example 5]
In Example 5, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 10 mW / cm ² and 0.5 seconds. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 5 is 5% of the irradiation amount in the main pressure bonding step. The connection sample according to Example 5 had a low initial conduction resistance of 1.2Ω and a conduction resistance of 4.5Ω after the reliability test. The amount of misalignment of the connected sample according to Example 5 was 0.6 μm.
[Example 6]
In Example 6, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 10 mW / cm ² and 2 seconds. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Example 6 is 20% of the irradiation amount in the main pressure bonding step. The connection sample according to Example 6 had a low initial conduction resistance of 1.3Ω, and the conduction resistance after the reliability test was 4.2Ω. The amount of misalignment of the connected sample according to Example 6 was 0.6 μm.

[Comparative Example 1]
In Comparative Example 1, the heat and pressure conditions in the temporary pressure bonding step were 7 MPa and 50 ° C., and the irradiation of ultraviolet rays was not performed. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 1 is 0% of the irradiation amount in the main pressure bonding step. The connection body sample according to Comparative Example 1 had a high initial conduction resistance of 3.4Ω and a conduction resistance of 6.1Ω after the reliability test. In addition, the amount of misalignment of the connector sample according to Comparative Example 1 was as large as 3.1 μm.

[Comparative Example 2]
In Comparative Example 2, the heat and pressure conditions in the temporary pressure bonding step were 7 MPa and 60 ° C., and irradiation with ultraviolet rays was not performed. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 2 is 0% of the irradiation amount in the main pressure bonding step. The connection sample according to Comparative Example 2 had an initial conduction resistance as low as 1.5Ω, but had a conduction resistance as high as 5.1Ω after the reliability test. Further, the amount of misalignment of the connector sample according to Comparative Example 2 was as large as 4.3 μm.

[Comparative Example 3]
In Comparative Example 3, the heat and pressure conditions in the temporary pressure bonding step were 7 MPa and 50 ° C., and the ultraviolet irradiation conditions were 15 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 3 is 1.5% of the irradiation amount in the main pressure bonding step. The connection sample according to Comparative Example 3 had an initial conduction resistance of 2.3Ω and a conduction resistance after the reliability test of 5.3Ω. The amount of misalignment of the connector sample according to Comparative Example 3 was 1.8 μm.

[Comparative Example 4]
In Comparative Example 4, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and irradiation with ultraviolet rays was not performed. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 4 is 0% of the irradiation amount in the main pressure bonding step. The connection body sample according to Comparative Example 4 had a low initial conduction resistance of 1.2Ω and a conduction resistance of 4.3Ω after the reliability test. However, the misalignment amount of the connector sample according to Comparative Example 4 was as large as 6.4 μm.

[Comparative Example 5]
In Comparative Example 5, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were ² mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 5 is 2% of the irradiation amount in the main pressure bonding step. The connection sample according to Comparative Example 5 had a low initial conduction resistance of 1.2Ω and a conduction resistance of 4.3Ω after the reliability test. However, the misalignment amount of the connector sample according to Comparative Example 5 was as large as 3.1 μm.

[Comparative Example 6]
In Comparative Example 6, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 25 mW / cm ² and 1 second. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 6 is 25% of the irradiation amount in the main pressure bonding step. The connected body sample according to Comparative Example 6 had an initial conduction resistance as high as 6.3Ω and a conduction resistance after the reliability test as high as 9.3Ω. However, the misalignment amount of the connector sample according to Comparative Example 6 was 0.3 μm.

[Comparative Example 7]
In Comparative Example 7, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 10 mW / cm ² and 0.2 seconds. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 7 is 2% of the irradiation amount in the main pressure bonding step. The connected sample according to Comparative Example 7 had a low initial conduction resistance of 1.1Ω and a conduction resistance of 4.5Ω after the reliability test. However, the misalignment amount of the connector sample according to Comparative Example 7 was as large as 3.1 μm.

[Comparative Example 8]
In Comparative Example 8, the heat and pressure conditions in the temporary pressure bonding step were 60 MPa and 80 ° C., and the ultraviolet irradiation conditions were 10 mW / cm ² and 2.5 seconds. The irradiation amount of ultraviolet rays in the temporary pressure bonding step of Comparative Example 8 is 25% of the irradiation amount in the main pressure bonding step. The connected sample according to Comparative Example 8 had an initial conduction resistance as high as 5.2Ω and a conduction resistance after the reliability test as high as 7.5Ω. The amount of misalignment of the connector sample according to Comparative Example 8 was as large as 1.2 μm.

As shown in Table 1, in Examples 1 to 6, ultraviolet rays were irradiated at an illuminance of 3 to 20 mW / cm ² and an irradiation time of 0.5 to 2 seconds in the temporary pressure bonding step. This is 3 to 20% of the irradiation amount in the main pressure bonding step. Therefore, in Examples 1 to 6, the curing reaction of the binder resin can be appropriately advanced to increase the viscosity, and the misalignment amount of the evaluation IC was 1.0 μm without inhibiting the intrusion of the conductive particles. Could be less than.

  Since Comparative Examples 1 and 2 did not irradiate ultraviolet rays in the temporary pressure bonding step, when the pressure was applied at a low temperature and a low pressure, the misalignment amount of the evaluation IC became large when pressed by the thermocompression bonding tool. Further, since the pressure was applied at a low pressure, the conductive particles were insufficiently pressed, and the conduction resistance increased after the reliability test.

  In Comparative Example 3, ultraviolet rays were radiated at an appropriate illuminance and time in the temporary pressure bonding step, but the pressing force of the evaluation IC was low, the pressing of the conductive particles was insufficient, and the conduction resistance increased.

  In Comparative Example 4, when the pressure was applied at a high pressure when the temporary pressure bonding step was performed without irradiating with ultraviolet rays, the conductive particles were able to be secured by the indentation of the conductive particles, but the misalignment amount became large.

In Comparative Example 5, since the ultraviolet illuminance in the temporary pressure bonding step was as low as ² mW / cm ² , the curing reaction of the binder resin did not proceed and the viscosity was low, so the conductivity could be secured by pushing the conductive particles. The amount of deviation has increased.

In Comparative Example 6, since the ultraviolet illuminance in the temporary pressure bonding step was as high as 25 mW / cm ² , misalignment could be suppressed, but on the other hand, the curing reaction of the binder resin proceeded too much and the conductive particles were sufficiently dispersed in the main pressure bonding step. I couldn't push it into, and the conduction resistance increased.

  In Comparative Example 7, since the ultraviolet irradiation time in the temporary pressure bonding step was as short as 0.2 seconds, the curing reaction of the binder resin did not proceed and the viscosity was low, so the conductivity could be secured by pushing the conductive particles, The amount of misalignment has increased.

  In Comparative Example 8, since the ultraviolet irradiation time in the temporary pressure bonding step was as long as 2.5 seconds, it was possible to suppress a large misalignment, but the curing reaction of the binder resin proceeded too much and the conductivity in the main pressure bonding step was increased. The particles could not be pushed in sufficiently and the conduction resistance increased.

  From the above, it is understood that by appropriately increasing the viscosity of the binder resin in the temporary pressure bonding step, it is possible to suppress the misalignment without hindering the intrusion of the conductive particles. Further, it is understood that the light irradiation amount in the temporary pressure bonding step is preferably 3 to 20% of the light irradiation amount in the main pressure bonding step.

[Examples 7 to 9]
In Examples 7 to 9, the anisotropic conductive film was attached to the ITO-coated glass in the same manner as in Examples 1, 2 and 5 described above, and the entire surface of the film was bonded from the anisotropic conductive film side under the same conditions as the temporary pressure bonding. Ultraviolet rays were irradiated (pre-irradiation) from the anisotropic conductive film side. An evaluation IC was placed on the anisotropic conductive film after ultraviolet irradiation, and temporary pressure bonding (light irradiation) was performed under the same conditions as in Examples 1, 2, and 5. For the pre-irradiation from the anisotropic conductive film side, a light source substantially the same as the light irradiation from the transparent substrate side was used. Then, the main pressure bonding was performed to obtain a connected body sample. The results of Examples 7 to 9 were substantially the same as those of Examples 1, 2, and 5.

<Second embodiment>
In this embodiment, the transparent substrate (chromium / aluminum coated glass: evaluation base material) and the electronic component (flexible substrate (FPC): evaluation element) are connected by changing the irradiation conditions of ultraviolet rays in the temporary pressure bonding step. , Got the connection. Then, for each of the obtained connection body samples, the conduction resistance value (Ω) between the electrode of the flexible substrate and the electrode of the chromium / aluminum-coated glass (aluminum) after the initial connection and after the reliability test, and the adhesive after the reliability test The amount of gap between the surface of the layer and the surface of the flexible substrate and the amount of misalignment were measured.

  The following anisotropic conductive film was used as an adhesive for connecting the chrome / aluminum coated glass and the flexible substrate. First, 30 parts by mass of phenoxy resin (YP-70: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP808: manufactured by Mitsubishi Chemical Co., Ltd.), and 20 parts by mass of solid epoxy resin (YD014: Nippon Steel & Sumikin Chemical Co., Ltd.), 3 parts by mass of conductive particles (AUL704: average particle size 4 μm, Sekisui Chemical Co., Ltd.), and 5 parts by mass of photocationic curing agent (LW-S1: San Apro Co., Ltd.). ) And 10 parts by mass of a cationic curing agent (SI-60L, manufactured by Sanshin Chemical Co., Ltd.) were uniformly mixed using a stirrer. This mixed solution was applied onto a PET film (thickness 50 μm) which had been subjected to a peeling treatment, and was molded into a film having a thickness 20 μm. Thereby, an anisotropic conductive film was obtained.

  As the flexible substrate, 200 μmP or 50 μmP (Line / Space = 1/1), Cu8 μmt-Sn plating, and 38 μmt-S'perflex base material were used.

  As the chrome / aluminum coating glass, aluminum pattern glass (200 μmP or 50 μmP, thickness 1.1 mm) was used.

[Example 10]
An anisotropic conductive film having a width of 1.5 mm was attached to the chrome / aluminum coated glass, and the flexible substrate was aligned on the anisotropic conductive film. From the chrome / aluminum coated glass side of the aligned laminate, an LED lamp (controller: ZUV-C20H, head unit: ZUV-H20MB, lens unit: ZUV-212L, made by OMRON) with a maximum emission wavelength of 360 nm is used. UV irradiation was performed for 1 second (irradiation amount: 40 mJ / cm ² ) with an illuminance of 40 mW / cm ² .

After irradiation with ultraviolet rays, a thermocompression bonding tool (1.5 mm width) was used to heat and press the buffer material (Teflon (registered trademark) sheet having a thickness of 50 μm) under the conditions of 120 ° C., 6 MPa and 5 seconds, and also the heating and pressing. After 3 seconds from the start, UV irradiation was performed from the chrome / aluminum coated glass side for 2 seconds (irradiation amount: 400 mJ / cm ² ) with an illuminance of 200 mW / cm ² using the LED lamp.

(Initial conduction resistance value and conduction resistance value after reliability test)
About the obtained connection sample, an initial conduction resistance value and a digital multimeter (trade name: Digital Multimeter 7561, manufactured by Yokogawa Electric Co., Ltd.) were used in the same manner as in the above-described first embodiment. The conduction resistance value was measured after the reliability test. The case where the initial conduction resistance value was less than 3Ω was evaluated as “A”, the case of 3Ω or more and less than 5Ω was evaluated as “B”, and the case of 5Ω or more was evaluated as “C”. Further, the conduction resistance value after the reliability test was evaluated as "A" when it was less than 5Ω, "B" when it was 5Ω or more and less than 10Ω, and "C" when it was 10Ω or more. Practically, the evaluation of the conduction resistance value is preferably “A” or “B”.

(Gap after reliability test)
With respect to the obtained connected body sample, gaps at the interfaces between the cured product of the anisotropic conductive film after the reliability test and the flexible substrate were measured at three positions, and the average value thereof was calculated. The case where the gap is 3.5 μm or less (70% or less of the average particle size of the conductive particles) is evaluated as “A”, and more than 3.5 μm and less than 4.5 μm (70% of the average particle size of the conductive particles is When it was more than 90% and less than 90%, it was evaluated as “B”, and when it was 4.5 μm or more (90% or more of the average particle diameter of the conductive particles), it was evaluated as “C”. Practically, the evaluation of the gap is preferably “A” or “B”.

(Amount of misalignment)
With respect to the obtained connection body sample, the amount of misalignment in the width direction between the terminal 45 of the chrome / aluminum coated glass and the terminal 46 of the flexible substrate was measured using a stereoscopic microscope (see FIG. 12). When the amount of misalignment was 3 μm or less, it was evaluated as “A”, when it was more than 3 μm and less than 5 μm, it was evaluated as “B”, and when it was 5 μm or more, it was evaluated as “C”.

As an evaluation criterion for the amount of misalignment, for example, as shown in FIG. 12, assuming that a terminal 45 and a terminal 46 having a connection width of 50 μmP and a connection width of 600 μm, the condition that the connection area per wiring is about 10,000 μm ² or less is NG. . That is, when the amount of misalignment was 8 μm or more ((25−8) μm × (600−8) μm = 10064 μm ² ) was set as NG. Then, assuming that the alignment tolerance of the apparatus is about 3 μm, the case where the amount of alignment deviation is less than 5 μm was judged to be practically preferable. Although the amount of misalignment is 5 μm or more, there is no practical problem, but a smaller amount is preferable from the viewpoint of quality control of the connection structure.

[Example 11]
Example 11 was the same as Example 10 except that the condition of UV irradiation before the main pressure bonding was changed to 1 second (irradiation amount: 20 mJ / cm ² ) with an illuminance of 20 mW / cm ² to obtain a connector sample. I went the same way.

[Example 12]
Example 12 was the same as Example 10 except that the condition of the ultraviolet irradiation before the main pressure bonding was changed to 1 second (irradiation amount: 100 mJ / cm ² ) with an illuminance of 100 mW / cm ² to obtain a connected body sample. I went the same way.

[Comparative Example 9]
In Comparative Example 9, the same procedure as in Example 10 was carried out except that the connector sample was obtained without performing the ultraviolet irradiation before the main pressure bonding.

[Comparative Example 10]
Comparative Example 10 was the same as Example 10 except that the condition of the UV irradiation before the main pressure bonding was changed to 1 second (irradiation amount: 8 mJ / cm ² ) with an illuminance of 8 mW / cm ² to obtain a connector sample. I went the same way.

[Comparative Example 11]
In Comparative Example 11, the conditions of the ultraviolet irradiation before the crimping, 1 second at an intensity 120 mW / cm ² (irradiation dose: 120mJ / cm ²⁾ except that to obtain a connection member sample was changed to, Example 10 I went the same way.

[Example 13]
In Example 13, the same procedure as in Example 10 was performed except that a flexible substrate of 50 μmP was used instead of the flexible substrate of 200 μmP to obtain a connected body sample.

[Example 14]
Example 14 was the same as Example 13 except that the condition of UV irradiation before main pressure bonding was changed to 1 second (irradiation amount: 8 mJ / cm ² ) with an illuminance of 8 mW / cm ² to obtain a connector sample. I went the same way.

[Example 15]
In Example 15, the conditions of the ultraviolet irradiation before the crimping, 1 second at an intensity 60 mW / cm ² (irradiation dose: 60mJ / cm ²⁾ except that to obtain a connection member sample was changed to, as in Example 13 I went the same way.

[Comparative Example 12]
In Comparative Example 12, the same procedure as in Example 13 was performed, except that the connected body sample was obtained without performing the ultraviolet irradiation before the main pressure bonding.

[Comparative Example 13]
Comparative Example 13 was the same as Example 13 except that the condition of UV irradiation before the main pressure bonding was changed to 1 second (irradiation amount: 4 mJ / cm ² ) with an illuminance of 4 mW / cm ² to obtain a connector sample. I went the same way.

[Comparative Example 14]
In Comparative Example 14, the conditions of the ultraviolet irradiation before the crimping, 1 second at an intensity 80 mW / cm ² (irradiation dose: 80mJ / cm ²⁾ except that to obtain a connection member sample was changed to, as in Example 13 I went the same way.

  In the table below, “(1) Before main pressure bonding” represents the conditions of light irradiation before main pressure bonding shown in (1) in FIG. In addition, “(2) At the time of main pressure bonding” represents the conditions of light irradiation at the time of main pressure bonding shown in (2) in FIG.

  In Examples 10 to 12 in which the minimum wiring space of the flexible substrate exceeds 25 μm, the light irradiation amount in the light irradiation step was set to 5 to 25% of the light irradiation amount in the main pressure bonding step. From this, it was found that the evaluation of the initial conduction resistance value, the conduction resistance value after the reliability test, the gap after the reliability test, and the amount of misalignment was good.

  In Examples 13 to 15 in which the space between the minimum wirings of the flexible substrate was 25 μm or less, the light irradiation amount in the light irradiation step was set to 2 to 15% of the light irradiation amount in the main pressure bonding step. From this, it was found that the evaluation of the initial conduction resistance value, the conduction resistance value after the reliability test, the gap after the reliability test, and the amount of misalignment was good.

  In Comparative Examples 9 and 12, since ultraviolet rays were not irradiated in the light irradiation step, the conduction resistance value after the reliability test, the gap after the reliability test, and the misalignment of the flexible substrate were evaluated during heating and pressing in the main pressure bonding step. Turned out not to be good. Further, in Comparative Examples 10 and 13, since the ultraviolet irradiation amount in the light irradiation step was too small as compared with the ultraviolet irradiation amount in the main pressure bonding step, the conduction resistance value after the reliability test and the gap after the reliability test were evaluated. Turned out not to be good. Moreover, in Comparative Example 13, it was found that the evaluation of the misalignment of the flexible substrate was not good. These results indicate that the fluidity of the binder resin that constitutes the anisotropic conductive film becomes too large during the heating and pressing in the main pressure bonding step, and the wiring between the flexible substrates is bent and the heating tool is pressed out. It is considered that when the residual stress of the flexible substrate is released, peeling easily occurs at the interface between the anisotropic conductive film and the flexible substrate.

  In Comparative Examples 11 and 14, since the ultraviolet irradiation amount in the light irradiation step was too large with respect to the ultraviolet irradiation amount in the main pressure bonding step, the initial conduction resistance value, the conduction resistance value after the reliability test, and the reliability test after the reliability test were performed. It was found that the evaluation of the gap was not good. It is considered that this result is because the curing reaction of the binder resin forming the anisotropic conductive film proceeded so much that the conductive particles could not be sufficiently pushed in in the main pressure bonding step.

[Examples 16 to 19]
In Examples 16 to 19, the anisotropic conductive film was attached to the chrome / aluminum coated glass in the same manner as in Examples 10, 11, 13 and 14, and the anisotropic conductive film was coated on the entire surface of the anisotropic conductive film. On the other hand, ultraviolet rays were irradiated (pre-irradiation) with 20 mJ / cm ² (5% at the time of main pressure bonding). For the pre-irradiation from the anisotropic conductive film side, a light source substantially the same as the light irradiation from the transparent substrate side was used. After ultraviolet irradiation, the flexible substrate was aligned on the anisotropic conductive film to obtain a laminate. This laminate was subjected to light irradiation and main pressure bonding under the same conditions as in Examples 10, 11, 13, and 14. In Examples 16 to 19, almost the same results as in Examples 10, 11, 13, and 14 were obtained.

[Examples 20 to 29]
In Examples 20 to 29, the anisotropic conductive film was attached to the chrome / aluminum coated glass in the same manner as in Examples 10 to 19 and pressed at 60 ° C. and 1 MPa when light was irradiated from the transparent substrate side in the temporary pressure bonding step. Other than the above, the same operation was repeated to perform the main pressure bonding. In Examples 20 to 29, substantially the same results as in Examples 10 to 19 were obtained.

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive film, 2 Release film, 3 Binder resin layer, 4 Conductive particles, 10 Liquid crystal display panel, 11,12 Transparent substrate, 13 Seal, 14 Liquid crystal, 15 Panel display part, 16,17 Transparent electrode, 18 Liquid crystal drive IC, 20 COG mounting part, 21 flexible substrate, 22 FOG mounting part, 24 thick film, 25, 26 polarizing plate, 30 heating and pressing head, 31 ultraviolet ray irradiator, 42 bump, 43 wiring, 44 gap, 45 , 46 terminals

Claims (18)

An adhesive placement step of providing an adhesive for circuit connection containing a photopolymerization initiator on a transparent substrate,
A light irradiation step of arranging electronic components on the transparent substrate via the circuit connecting adhesive, and irradiating the circuit connecting adhesive with light,
While pressing the electronic component against the transparent substrate, having a main pressure bonding step of heating and light irradiation,
The method for manufacturing a connector, wherein the light irradiation amount in the light irradiation step is smaller than the light irradiation amount in the main pressure bonding step. Between the adhesive placement step and the light irradiation step, further has a pre-irradiation step of performing light irradiation from the circuit connection adhesive side to the entire surface of the circuit connection adhesive,
The method for manufacturing a connector according to claim 1, wherein the total light irradiation amount of the pre-irradiation step and the light irradiation step is smaller than the light irradiation amount of the main pressure bonding step.   The said light irradiation process is a manufacturing method of the connection body of Claim 1 or 2 which performs light irradiation from the said transparent substrate side.   The method for manufacturing a connected body according to claim 1, wherein in the light irradiation step, a light irradiation amount is changed depending on a minimum inter-wiring space of the electronic component.   The method for manufacturing a connector according to claim 1, wherein a light irradiation time in the light irradiation step is ⅕ or less of a pressure bonding time in the main pressure bonding step. An adhesive placement step of providing an adhesive for circuit connection containing a photopolymerization initiator on a transparent substrate,
Placing an electronic component on the transparent substrate via the circuit connecting adhesive, pressing the transparent substrate of the electronic component, and a temporary pressure bonding step of performing light irradiation to the circuit connecting adhesive,
While pressing the electronic component against the transparent substrate, having a main pressure bonding step of heating and light irradiation,
The method for manufacturing a connector, wherein the light irradiation amount in the temporary pressure bonding step is smaller than the light irradiation amount in the main pressure bonding step. Between the adhesive placement step and the temporary pressure bonding step, further has a pre-irradiation step of irradiating the entire surface of the circuit connection adhesive with light from the circuit connection adhesive side,
The method for manufacturing a connector according to claim 6, wherein the total light irradiation amount of the pre-irradiation step and the temporary pressure bonding step is smaller than the light irradiation amount of the main pressure bonding step.   The method for manufacturing a connector according to claim 6 or 7, wherein in the temporary pressure bonding step, light irradiation is performed from the transparent substrate side.   The method for manufacturing a connected body according to claim 6, wherein in the temporary pressure bonding step, a light irradiation amount is changed depending on a minimum inter-wiring space of the electronic component.   The method for manufacturing a connector according to claim 6, wherein the light irradiation amount in the temporary pressure bonding step is 3 to 20% of the light irradiation amount in the main pressure bonding step. The method for manufacturing a connector according to claim 10, wherein the illuminance of light in the temporary pressure bonding step is 3 to 20 mW / cm ² . The method for producing a connected body according to claim 10, wherein the irradiation time of light in the temporary pressure bonding step is 0.5 to 2 seconds.   The method for manufacturing a connector according to any one of claims 6 to 12, wherein the pressing force applied to the electronic component in the temporary pressure bonding step is 40 to 90% of the pressing force applied to the electronic component in the main pressure bonding step. .   The method for manufacturing a connector according to claim 6, wherein in the temporary pressure bonding step, light irradiation is started at the same time when the pressure bonding tool is brought into contact with the pressing surface of the electronic component.   The method for producing a connected body according to any one of claims 6 to 13, wherein light irradiation is performed on the adhesive for circuit connection from the adhesive placement step.   The method for manufacturing a connector according to any one of claims 6 to 15, wherein a pressure bonding temperature of the electronic component in the temporary pressure bonding step is equal to a pressure bonding temperature of the electronic component in the main pressure bonding step. An adhesive placement step of providing an adhesive for circuit connection containing a photopolymerization initiator on a transparent substrate,
A light irradiation step of arranging electronic components on the transparent substrate via the circuit connecting adhesive, and irradiating the circuit connecting adhesive with light,
While pressing the electronic component against the transparent substrate, having a main pressure bonding step of heating and light irradiation,
The method of connecting electronic components, wherein the light irradiation amount in the light irradiation step is smaller than the light irradiation amount in the main pressure bonding step.   In the light irradiation step, an electronic component is arranged on the transparent substrate via the circuit connecting adhesive, the electronic component is pressed against the transparent substrate, and the circuit connecting adhesive is irradiated with light. The method of connecting electronic components according to claim 17, which is a temporary pressure bonding step.

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