JP2015118998A - Method of manufacturing connection body, connection method, and connection body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve poor connection of an electronic component, while suppressing warpage of a substrate by using stage heating.SOLUTION: In a method of manufacturing a connection body where an electronic component 18 is connected onto a substrate 12 via an adhesive 1, by mounting a temporary connection body 21, where the electronic component 18 is mounted on the substrate 12 via an uncured adhesive 1, on a stage 31 having a temperature control mechanism 32, heating the substrate 12 side by means of the stage 31, and hot pressing the electronic component 18 onto the substrate 12 by means of a hot press head 33, the substrate 12 is preheated by means of the stage 31, prior to the hot press process by means of the hot press head 33.

Description

  The present invention relates to a method for manufacturing a connection body in which an electronic component is connected on a substrate via an adhesive, and a connection method for connecting an electronic component on a substrate via an adhesive, and more particularly to an electronic component via an adhesive. The present invention relates to a method for manufacturing a connection body, a connection method for an electronic component, and a connection body that are connected by heating and pressing a substrate.

  Conventionally, a liquid crystal display device has been widely used as various display means such as a television, a PC monitor, a mobile phone, a portable game machine, a tablet PC, or an in-vehicle monitor. In recent years, in such liquid crystal display devices, so-called COG (chip on glass) in which a liquid crystal driving IC is directly mounted on a glass substrate of a liquid crystal display panel, or liquid crystal driving, from the viewpoint of fine pitch, light weight and thinning. A so-called FOG (film on glass) is employed in which a flexible substrate on which a circuit is formed is directly mounted on a substrate of a liquid crystal display panel.

  For example, as shown in FIG. 4, a liquid crystal display device 100 employing a COG mounting system has a liquid crystal display panel 104 that performs a main function for liquid crystal display. The liquid crystal display panel 104 is a glass substrate or the like. And two transparent substrates 102 and 103 facing each other. In the liquid crystal display panel 104, the transparent substrates 102 and 103 are bonded to each other by a frame-shaped seal 105, and the liquid crystal 106 is sealed 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 on both inner surfaces facing each other so as to intersect each other. The transparent substrates 102 and 103 are configured such that a pixel as a minimum unit of liquid crystal display is constituted by the intersection of the transparent electrodes 108 and 109.

  Of the two transparent substrates 102 and 103, one transparent substrate 103 is formed to have a larger planar dimension than the other transparent substrate 102, and the transparent electrode 109 is formed on the edge 103a of the transparent substrate 103 formed to be large. Terminal portion 109a is formed. Further, alignment films 111 and 112 subjected to a predetermined rubbing process are formed on both transparent electrodes 108 and 109, and the initial alignment of liquid crystal molecules is regulated by the alignment films 111 and 112. ing. Further, a pair of polarizing plates 118 and 119 are disposed outside the transparent electrodes 108 and 109, and the vibration direction of transmitted light from the light source 120 such as a backlight is regulated by the polarizing plates 118 and 119. It has come to be.

  On the terminal portion 109a, a liquid crystal driving IC 115 is thermocompression bonded via an anisotropic conductive film 114. The anisotropic conductive film 114 is a film formed by mixing conductive particles in a thermosetting binder resin, and heat conduction is performed between the two conductors so that the electrical conduction between the conductors is achieved by the conductive particles. And the mechanical connection between the conductors is maintained by the binder resin. The liquid crystal driving IC 115 can perform predetermined liquid crystal display by selectively changing the alignment of the liquid crystal by selectively applying a liquid crystal driving voltage to the pixels. In addition, as an adhesive which comprises the anisotropic conductive film 114, a highly reliable thermosetting adhesive is normally used.

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

  However, in such a connection method using an anisotropic conductive film, the heat pressing temperature is high, and the thermal shock to the electronic components such as the liquid crystal driving IC 115 and the transparent substrate 103 is increased. In addition, the temperature difference between the liquid crystal driving IC 115 heated by the thermocompression bonding head 121 and the transparent substrate 103 placed on the stage when the temperature drops to room temperature after the anisotropic conductive film is connected. Further, the transparent substrate 103 may be warped due to a difference in thermal expansion coefficient between the binder and the transparent substrate 103. For this reason, there is a problem that non-uniformity of display is caused, and there is a possibility that problems such as poor connection of the liquid crystal driving IC 115 occur when the warp is large. This phenomenon has become a prominent problem as ICs and glass substrates are made thinner.

JP-A-2005-206220

  An essential cause of the warp of the transparent substrate 103 due to the COG connection is a temperature difference between the thermocompression bonding head 121 and the stage. For this reason, the temperature difference between the thermocompression bonding head 121 and the stage can be reduced also by the method of increasing the stage temperature.

  However, in the connection method using stage heating, it is possible to effectively suppress the warping of the transparent substrate by raising the heating temperature of the stage, but the heat of the stage is transmitted to the binder resin temporarily attached to the transparent substrate. Further, the binder resin is cured before the main press bonding, and the conductive particles cannot be pushed in even by the heat pressing by the thermocompression bonding head in the main press bonding step, which may increase the conduction resistance.

  The present invention solves the above-mentioned problems, and suppresses the warping of the substrate by using stage heating and improves the connection failure of the electronic component, the connection method of the electronic component, and this An object of the present invention is to provide a connection body manufactured using the same.

  In order to solve the above-described problems, a connection body manufacturing method according to the present invention includes a temporary connection body in which an electronic component is mounted on a substrate via an uncured adhesive on a stage having a temperature control mechanism. A connected body in which the electronic component is heated and pressed on the substrate by a thermocompression bonding head, and the electronic component is connected to the substrate via the adhesive. In this manufacturing method, the substrate is preheated by the stage prior to the heating and pressing step by the thermocompression bonding head.

  Further, the connection method according to the present invention is such that a temporary connection body in which an electronic component is mounted on a substrate via an uncured adhesive is placed on a stage having a temperature control mechanism, and the substrate side is placed by the stage. In the connection method in which the electronic component is heated and pressed onto the substrate by the thermocompression bonding head and the electronic component is connected to the substrate through the adhesive, the heating and pressing step by the thermocompression bonding head is used. First, the substrate is preheated by the stage.

  Moreover, the connection body which concerns on this invention is manufactured by the said method.

  According to the present invention, prior to the heat pressing by the thermocompression bonding head, preheating is performed to heat the substrate of the temporary connection body by stage heating, so that the temperature of the substrate is raised in advance, and the electrons heated and pressed by the thermocompression bonding head. The temperature difference from the parts was reduced, and the occurrence of warpage could be suppressed. In addition, according to the present invention, by performing preheating with a predetermined temperature profile, the curing reaction of the binder resin due to preheating is suppressed, and in the heat pressing process by the thermocompression bonding head, the electrical conductivity between the electronic component and the substrate is improved. Can be improved.

FIG. 1 is a cross-sectional view showing a mounting process to which the present invention is applied. FIG. 2 is a cross-sectional view showing an anisotropic conductive film. FIG. 3 is a graph showing a temperature profile of the anisotropic conductive film in the preheating step. FIG. 4 is a cross-sectional view showing a conventional liquid crystal display panel. FIG. 5 is a cross-sectional view showing a COG mounting process of a conventional liquid crystal display panel.

  Hereinafter, a method for manufacturing a connection body, a connection method, and a connection body to which the present invention is applied 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 be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Hereinafter, a case where so-called COG (chip on glass) mounting in which an IC chip for driving a liquid crystal as an electronic component is mounted on a glass substrate of a liquid crystal display panel will be described as an example. As shown in FIG. 1, the liquid crystal display panel 10 includes two transparent substrates 11 and 12 made of a glass substrate and the like, and the transparent substrates 11 and 12 are bonded to each other by a frame-shaped seal 13. . In the liquid crystal display panel 10, the liquid crystal 14 is sealed in a space surrounded by the transparent substrates 11 and 12 to form a panel display unit 15.

  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 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 configured by the intersection of the transparent electrodes 16 and 17.

  Of the transparent substrates 11 and 12, one transparent substrate 12 is formed to have a larger planar dimension than the other transparent substrate 11, and an edge 12a of the formed transparent substrate 12 has an electronic component. A COG mounting unit 20 on which the liquid crystal driving IC 18 is mounted is provided.

  Note that the liquid crystal driving IC 18 can selectively apply a liquid crystal driving voltage to the pixels to partially change the alignment of the liquid crystal and perform a predetermined liquid crystal display.

  In the COG mounting part 20, a terminal part 17a of the transparent electrode 17 is formed. On the terminal portion 17a, a liquid crystal driving IC 18 is connected using the anisotropic conductive film 1 as a circuit connecting adhesive. The anisotropic conductive film 1 contains conductive particles 4, and the conductive particles 4 include the electrodes of the liquid crystal driving IC 18 and the terminal portions 17 a of the transparent electrodes 17 formed on the edge 12 a of the transparent substrate 12. It is electrically connected via The anisotropic conductive film 1 is a thermosetting adhesive, and is thermally bonded by a thermocompression bonding head 33 to be described later, so that the binder resin is fluidized and the conductive particles 4 are connected to the terminal portions 17a and the liquid crystal driving IC 18. In this state, the binder resin is cured. Thereby, the anisotropic conductive film 1 electrically and mechanically connects the transparent substrate 12 and the liquid crystal driving IC 18.

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

[Anisotropic conductive film]
Next, the anisotropic conductive film 1 will be described. As shown in FIG. 2, an anisotropic conductive film (ACF) 1 usually has a binder resin layer (adhesive layer) 3 containing conductive particles 4 on a release film 2 as a base material. It is formed. As shown in FIG. 1, the anisotropic conductive film 1 is formed by interposing a binder resin layer 3 between a transparent electrode 17 formed on the transparent substrate 12 of the liquid crystal display panel 10 and a liquid crystal driving IC 18. It is used to connect the display panel 10 and the liquid crystal driving IC 18 so as to be conductive.

  The adhesive composition of the binder resin layer 3 is composed of a normal binder component containing, for example, a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent, and the like.

  As the film-forming resin, a resin having an average molecular weight of about 10,000 to 80,000 is preferable, and various resins such as an epoxy resin, a modified epoxy resin, a urethane resin, and a phenoxy resin are particularly mentioned. Among these, phenoxy resin is preferable from the viewpoint of film formation state, connection reliability, and the like.

  It does not specifically limit as a thermosetting resin, For example, a commercially available epoxy resin can be used. Examples of such epoxy resins include naphthalene type epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, bisphenol type epoxy resins, stilbene type epoxy resins, triphenolmethane type epoxy resins, phenol aralkyl type epoxy resins, and naphthols. Type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like. These may be used alone or in combination of two or more.

  As the latent curing agent, a heat curing type curing agent can be suitably used. The latent curing agent does not normally react, but is activated by various triggers selected according to applications such as heat and pressure, and starts the reaction. The activation method of the thermally activated latent curing agent includes a method of generating active species (cations and anions) by a dissociation reaction by heating, and the like. There are a method of starting a curing reaction by dissolving and dissolving, a method of starting a curing reaction by eluting a molecular sieve encapsulated type curing agent at a high temperature, and a method of elution / curing using a microcapsule. Thermally active latent curing agents include imidazole, hydrazide, boron trifluoride-amine complexes, sulfonium salts, amine imides, polyamine salts, dicyandiamide, etc., and modified products thereof. The above mixture may be sufficient. Among these, a microcapsule type imidazole-based latent curing agent is preferable.

  Examples of the silane coupling agent include epoxy-based, amino-based, mercapto-sulfide-based, and ureido-based agents. By adding the silane coupling agent, the adhesion at the interface between the organic material and the inorganic material is improved.

  Examples of the conductive particles 4 include particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver and gold, metal oxides, carbon, graphite, glass and ceramics, The surface of particles of plastic or the like coated with metal, or the surface of these particles further coated with an insulating thin film can be used. When using a resin particle surface coated with metal, the resin particles include, for example, epoxy resin, phenol resin, acrylic resin, acrylonitrile / styrene (AS) resin, benzoguanamine resin, divinylbenzene resin, styrene resin, etc. Particles can be mentioned. In addition, as for the electroconductive particle 4, the whole particle | grain may be formed only with the electroconductive material.

  The adhesive composition constituting the binder resin layer 3 is not limited to the case where it contains a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent, etc. You may make it comprise from any material used as an adhesive composition of a film.

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

  Although the anisotropic conductive film 1 may be produced by any method, for example, it can be produced by the following method. An adhesive composition containing a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent, conductive particles and the like is prepared. An anisotropic conductive film 1 in which the binder resin layer 3 is supported on the release film 2 by applying the adjusted adhesive composition onto the release film 2 using a bar coater, a coating apparatus, and the like, and drying the oven composition or the like. Get.

[2-layer ACF]
Moreover, the anisotropic conductive film 1 which concerns on this invention has the binder resin layer 3 containing the electroconductive particle 4, and the insulating adhesive layer which consists of an insulating adhesive composition which does not contain electroconductive particle. It is good also as an anisotropic conductive film of the 2 layer structure laminated | stacked.

  The insulating adhesive composition constituting the insulating adhesive layer is composed of a normal binder component containing a film-forming resin, a thermosetting resin, a latent curing agent, a silane coupling agent, and the like. It can be comprised with the material similar to the adhesive composition of the layer 3. FIG.

  The anisotropic conductive film 1 having a two-layer structure is formed by applying an adhesive composition constituting an insulating adhesive layer to a release film and drying the binder resin layer 3 supported by the release film 2 described above. It can be formed by bonding.

[Production method]
Next, a manufacturing process of a connection body in which the liquid crystal driving IC 18 is connected to the transparent electrode 17 of the transparent substrate 12 through the anisotropic conductive film 1 will be described. First, the anisotropic conductive film 1 is temporarily pressure-bonded onto the transparent electrode 17. The method for temporarily pressing the anisotropic conductive film 1 is to dispose the anisotropic conductive film 1 on the transparent electrode 17 of the transparent substrate 12 of the liquid crystal display panel 10 so that the binder resin layer 3 is on the transparent electrode 17 side. To do.

  And after arrange | positioning the binder resin layer 3 on the transparent electrode 17, the binder resin layer 3 is heated and pressurized with the heating press head for temporary attachment from the peeling film 2 side, a heating press head is released from the peeling film 2, and it peels. By peeling the film 2 from the binder resin layer 3 on the transparent electrode 17, only the binder resin layer 3 is temporarily attached on the transparent electrode 17. Temporary pressure bonding by the heating and pressing head is performed by heating (for example, about 70 to 100 ° C.) while pressing the upper surface of the release film 2 to the transparent electrode 17 side with a slight pressure (for example, about 0.1 to 2 MPa).

  Next, the temporary connection body 21 is formed by arranging the liquid crystal driving IC 18 so that the transparent electrode 17 of the transparent substrate 12 and the electrode terminal of the liquid crystal driving IC 18 face each other with the binder resin layer 3 therebetween. The temporary connection body 21 is placed on the stage 31 of the connection device 30 (see FIG. 1).

[Connecting device]
The connection device 30 is used in a manufacturing process of a connection body in which the liquid crystal driving IC 18 is connected to the transparent electrode 17 of the transparent substrate 12 through the anisotropic conductive film 1. As shown in FIG. A stage 31 on which the connection body 21 is placed, a heating mechanism 32 for heating the stage 31, and a liquid crystal driving IC 18 mounted on the transparent substrate 12 placed on the stage 31 via the anisotropic conductive film 1 And a head moving mechanism 34 that moves the thermocompression bonding head 33.

  The stage 31 has the edge 12 a of the transparent substrate 12 placed on the surface thereof and is opposed to the thermocompression bonding head 33. Further, the stage 31 is heated to a high temperature (for example, 80 to 100 ° C.) such that the binder resin layer 3 is not cured by a heating mechanism 32 such as a heater. Thereby, the stage 31 reduces the heating temperature difference between the transparent substrate 12 placed on the surface and the liquid crystal driving IC 18 heated and pressed by the thermocompression bonding head 33 and the binder resin layer 3 of the anisotropic conductive film 1. can do. For this reason, it is preferable to form the stage 31 with a material having good thermal conductivity such as ceramic.

  The heating mechanism 32 for heating the stage 31 is, as will be described later, a known control method such as PID control (Proportional Integral Derivative Controller) prior to the heat pressing process by the thermocompression bonding head 33 in the main pressure bonding process of the liquid crystal driving IC 18. By controlling the heating temperature of the stage 31, the preliminary connection body 21 is preheated with a predetermined temperature profile.

  The thermocompression bonding head 33 heats and presses the liquid crystal driving IC 18 mounted on the transparent substrate 12 with the anisotropic conductive film 1 interposed therebetween, and a predetermined resin that cures the binder resin of the anisotropic conductive film 1 by the heater. Heated to a temperature (eg 200-250 ° C.). Further, the thermocompression bonding head 33 is held by the head moving mechanism 34 so as to be close to and away from the stage 31.

  The thermocompression bonding head 33 heats and presses the liquid crystal driving IC 18 against the transparent substrate 12 by the head moving mechanism 34 when the liquid crystal driving IC 18 is connected. By being heated and pressed by the thermocompression bonding head 33, the binder resin of the anisotropic conductive film 1 exhibits fluidity and flows out from between the terminal portion 17a of the transparent electrode 17 and the terminal portion of the liquid crystal driving IC 18; The conductive particles 4 are sandwiched, and the binder resin is cured in this state. When the connection process of the liquid crystal driving IC 18 is completed, the thermocompression bonding head 33 is separated above the stage 31 by the head moving mechanism 34 and waits until the temporary connection body 21 is newly placed on the stage 31.

[Connection process]
Next, a connection process using the connection device 30 will be described. In the connection process, as shown in FIG. 1, first, the temporary connection body 21 is placed on the stage 31. The temporary connection body 21 is opposed to a thermocompression bonding head 33 on which the transparent substrate 12 is placed on the stage 31 and the liquid crystal driving IC 18 stands by above the stage 31.

[Preheating]
Here, in this connection process, preheating by the stage 31 is started with a predetermined temperature profile prior to the heat pressing process by the thermocompression bonding head 33, and then the heat pressing process by the thermocompression bonding head 33 is performed. Specifically, the temperature control of the stage 31 is performed by the heating mechanism 32, and the temperature profile is set for all preliminary operations from when the temporary connection body 21 is placed on the stage 31 until the heat pressing by the thermocompression bonding head 33 is started. The rate of temperature increase of the binder resin layer 3 when 50% of the heating time has elapsed is set to 50% or less of the total temperature increase due to preheating, and more preferably, the temperature of the binder resin layer 3 when 50% of the total preheating time has elapsed. The temperature increase rate is set to 25% or less of the total temperature increase due to the preheating.

  In FIG. 3, the temperature profile of the binder resin layer 3 by preheating is shown. In FIG. 3, temperature gradient 1 is a temperature profile when the rate of temperature increase of the binder resin layer 3 when 50% of the total preheating time has elapsed is 25% of the total temperature increase due to preheating. In FIG. 3, the temperature gradient 2 is a temperature profile when the rate of temperature increase of the binder resin layer 3 when 50% of the total preheating time has elapsed is 50% of the total temperature increase due to preheating. The temperature gradient 3 is a temperature profile when the rate of temperature increase of the binder resin layer 3 at the time of 50% of the total preheating time is 75% of the total temperature increase due to preheating.

  As shown in FIG. 3, when the temporary connection body 21 is placed on the stage 31, the heating mechanism 32 gradually increases the stage temperature, and when the predetermined preheating time has elapsed, the binder resin layer 3 is predetermined. Heat to reach a temperature of. At this time, according to the temperature profile of the temperature gradient 1, when 50% of the total preheating time has elapsed, the binder resin layer 3 is heated to 25% of the total temperature increase temperature, and the subsequent preheating time is 50%. Increase the temperature by 75% of the total temperature increase. Further, according to the temperature profile of the temperature gradient 2, when 50% of the total preheating time has elapsed, the binder resin layer 3 is heated to 50% of the total temperature increase temperature, and then the entire preheating time is 50%. Raise the temperature by 50% of the temperature rise.

  By controlling the temperature of the stage 31 so that the temperature profiles according to the temperature gradient 1 and the temperature gradient 2 are obtained, in the preheating performed before the heat pressing process by the thermocompression bonding head 33 of the temporary connection body 21, The temperature is increased and the temperature difference with the liquid crystal driving IC 18 heated and pressed by the thermocompression bonding head 33 in the main compression bonding step is reduced to suppress the occurrence of warpage and to prevent the binder resin layer 3 from being cured before the main compression bonding. can do. Therefore, in the main press-bonding step, the binder resin is caused to flow out from between the terminal of the liquid crystal driving IC 18 and the terminal portion 17a of the transparent electrode 17 by heating and pressing with the thermo-compression head 33, and the conductive particles 4 are placed between both terminals. It can be cured in a crushed state.

  On the other hand, as shown in the temperature gradient 3, as the temperature profile of the binder resin layer 3 in the preheating, the temperature increase rate of the binder resin layer 3 when 50% of the total preheating time has elapsed is the total temperature increase temperature by the preheating. If it is higher than 50%, the curing reaction of the binder resin layer 3 proceeds before the main press bonding, and the binder resin is also removed from the terminals of the liquid crystal driving IC 18 and the transparent electrode 17 by the heat pressing by the thermocompression bonding head 33 in the main press bonding step. It cannot flow out from between the portions 17a, and the conductive particles 4 cannot be pushed between both terminals, and the conduction resistance increases.

[Main crimping]
After preliminary heating, the upper surface of the liquid crystal driving IC 18 is subjected to main pressure bonding by heat-pressing at a predetermined temperature, pressure and time with a thermocompression bonding head 33 which has been heated to a predetermined heating temperature. The heat and pressure conditions by the thermocompression bonding head 33 are set to a predetermined temperature (for example, 230 ° C.), pressure (for example, 60 MPa), and time (for example, 5 seconds) for curing the binder resin layer 3.

  As a result, the terminal portion 17a of the transparent electrode 17 and the electrode terminal of the liquid crystal driving IC 18 are electrically connected via the conductive particles 4, and the binder resin heated by the thermocompression bonding head 33 in this state is cured. To do. The conductive particles 4 that are not between the terminals are dispersed in the binder resin and maintain an electrically insulated state. Thereby, electrical conduction is achieved only between the transparent electrode 17 of the transparent substrate 12 and the electrode terminal of the liquid crystal driving IC 18.

  At this time, in the manufacturing process according to the present invention, the temperature of the stage 31 is controlled as described above to heat the binder resin layer 3 in the preheating while suppressing the curing of the binder resin layer 3. Can flow out from between the electrode terminal of the liquid crystal driving IC 18 and the terminal portion 17a of the transparent electrode 17, and the conductive particles 4 can be cured while being crushed between the two terminals. Further, since the temperature difference between the transparent substrate 12 and the liquid crystal driving IC 18 is reduced by the preheating, the warp of the transparent substrate 12 is suppressed even after connection, and problems such as display unevenness can be prevented.

  Thereby, a connection body in which the transparent substrate 12 and the liquid crystal driving IC 18 are connected via the anisotropic conductive film 1 can be manufactured.

  As described above, the COG mounting in which the liquid crystal driving IC is directly mounted on the glass substrate of the liquid crystal display panel has been described as an example. However, the present technology is a COB mounting in which electronic components such as an IC chip are connected to a rigid substrate such as a glass epoxy substrate. It can also be applied to various connections such as.

[Others]
In the above, the anisotropic conductive film 1 having a film shape as the conductive adhesive has been described. Moreover, even if this invention is used for the connection process by the insulating adhesive film which consists of the binder resin layer which does not contain the electroconductive particle 4, and the paste-form binder resin which does not contain the electroconductive particle 4, it uses. Good. The adhesive according to the present invention is not limited to the presence or absence of the conductive particles 4 or the form of a film or paste.

  Next, examples of the present invention will be described. In this example, as a connection body sample, each connection body sample manufactured by connecting an evaluation IC on a glass substrate for evaluation with different anisotropic conductive film curing conditions was used. The amount of warpage was measured and evaluated.

[Preparation of anisotropic conductive film]
As an adhesive used for connection of the evaluation IC, an anisotropic conductive film having a two-layer structure in which the following conductive particle-containing layer and an insulating adhesive layer were laminated was prepared.

(Conductive particle-containing layer)
30 parts by mass of bis A type phenoxy resin (trade name YP50, manufactured by Nippon Steel Chemical Co., Ltd.), 30 parts by mass of bisphenol A type liquid epoxy resin (trade name EP 828, manufactured by Mitsubishi Chemical Corporation), imidazole-based latent curing agent (trade name) PHX3941HP, manufactured by Asahi Kasei Co., Ltd.) 40 parts by mass, epoxy silane coupling agent (trade name A-187, manufactured by Momentive Performance Materials Co., Ltd.) 1 part by mass, conductive particles having a particle diameter of 3.25 μm (trade name) Toluene was added to 35 parts by mass of Micropearl AU (manufactured by Sekisui Chemical Co., Ltd.) to prepare a composition having a solid content of 50%. The adjusted composition was applied onto a release film and dried by heating in an oven to produce a conductive particle-containing layer having a thickness of 8 μm.

(Insulating adhesive layer)
25 parts by mass of bis A type phenoxy resin (trade name YP50, manufactured by Nippon Steel Chemical Co., Ltd.), 35 parts by mass of bisphenol A type liquid epoxy resin (trade name EP 828, manufactured by Mitsubishi Chemical Corporation), imidazole-based latent curing agent (trade name) PHX3941HP (manufactured by Asahi Kasei Co., Ltd.) 40 parts by mass, epoxy-based silane coupling agent (trade name A-187, manufactured by Momentive Performance Materials Co., Ltd.) 1 part by mass of toluene to prepare a composition having a solid content of 50% did. The adjusted composition was applied onto a release film and dried by heating in an oven to prepare an insulating adhesive layer having a thickness of 12 μm.

  By laminating the conductive particle-containing layer thus adjusted and the insulating adhesive layer, a two-layer anisotropic conductive film was produced.

[IC for evaluation]
As an evaluation element, an evaluation IC having an outer shape: 2.0 mm × 20 mm, a thickness of 0.5 mm, a space between bumps: 20 μm, a bump height: 15 μm (Au-plated) was used.

[Evaluation Glass Substrate]
As an evaluation glass substrate to which the evaluation IC is connected, an ITO pattern glass having an outer shape: 30 mm × 50 mm, a thickness of 0.5 mm, and a space between bumps: 20 μm was used.

[Manufacture of temporary connections]
First, a glass substrate for evaluation was placed on a substrate support base of a temporary pressure bonding apparatus. An anisotropic conductive film was arranged on the connection surface of the glass substrate placed on the substrate support so that the conductive particle-containing layer was opposed to the connection surface. Then, the head part of the pressure bonder was heated to 80 ° C., and the pressure surface of the heated head part was pressed onto the upper surface of the insulating adhesive layer from above the release film and pressurized at 1 MPa for 2 seconds. An anisotropic conductive film was temporarily pressure-bonded on the glass substrate by this heat and pressure. Thereafter, the release film was peeled off, and the connection surface on which the bump of the evaluation IC was formed was placed on the anisotropic conductive film while aligning the bump and the wiring electrode, thereby manufacturing a temporary connection body.

  Subsequently, the IC for evaluation was connected to the glass substrate by the method according to Examples and Comparative Examples shown below to produce a connection body.

[Example 1]
In Example 1, the glass substrate of the temporary connection body was fixed on the heating stage of the connection device before the main pressure bonding step, and preheating was performed for 10 seconds. The heating stage is initially set to 30 ° C., and the stage temperature is adjusted by the heating mechanism so that the anisotropic conductive film has a temperature profile of 45 ° C. 5 seconds after the temporary connection body is mounted and 90 ° C. after 10 seconds. It was adjusted. The temperature of the anisotropic conductive film was measured by placing a thermocouple between the evaluation IC and the glass substrate.

  The temperature profile of the preheating according to Example 1 is as shown by the temperature gradient 1 in FIG. In Example 1, the temperature of the anisotropic conductive film was increased by 60 ° C. from 30 ° C. to 90 ° C. in 10 seconds by preheating. Then, when 50% of the total preheating time for 10 seconds had elapsed (after 5 seconds), the temperature was raised by 25% (15 ° C.) to the temperature raised by the stage heating (60 ° C.) to 45 ° C.

  After preheating, the upper surface of the IC for evaluation is heated to the curing temperature (200 ° C.) of the thermosetting resin in the anisotropic conductive film while pressing the upper surface of the evaluation IC with a pressure of 60 MPa for 5 seconds. The conductive film was cured, and the evaluation IC was finally bonded. Thus, a connection body in which the evaluation IC and the glass substrate were connected was manufactured.

[Example 2]
In Example 2, preheating was performed for 5 seconds. The heating stage is initially set to 30 ° C., and the stage is set by the heating mechanism so that the anisotropic conductive film has a temperature profile of 45 ° C. 2.5 seconds after mounting the temporary connection body and 90 ° C. after 5 seconds. The temperature was adjusted.

  The temperature profile of the preheating according to Example 2 is as shown by the temperature gradient 1 in FIG. In Example 2, the temperature of the anisotropic conductive film was raised by 60 ° C. from 30 ° C. to 90 ° C. in 5 seconds by preheating. Then, when 50% of the total preheating time for 5 seconds had elapsed (after 2.5 seconds), the temperature was raised by 25% (15 ° C.) to the temperature raised by the stage heating (60 ° C.) to 45 ° C. After preheating, the main press bonding step was performed under the same conditions as in Example 1 to manufacture a connection body.

[Example 3]
In Example 3, preheating was performed for 10 seconds. The heating stage is initially set to 30 ° C., and the stage temperature is set by the heating mechanism so that the anisotropic conductive film has a temperature profile of 60 ° C. 5 seconds after mounting the temporary connection body and 90 ° C. after 10 seconds. It was adjusted.

  The temperature profile of preheating according to Example 3 is as shown by the temperature gradient 2 in FIG. In Example 3, the temperature of the anisotropic conductive film was increased by 60 ° C. from 30 ° C. to 90 ° C. in 10 seconds by preheating. Then, when 50% of the total preheating time for 10 seconds had elapsed (after 5 seconds), the temperature was raised by 50% (30 ° C.) to the temperature raised by the stage heating (60 ° C.) to 60 ° C. After preheating, the main press bonding step was performed under the same conditions as in Example 1 to manufacture a connection body.

[Comparative Example 1]
In Comparative Example 1, the main crimping process was immediately performed on the temporary connection body without performing preheating. The main pressure bonding conditions are the same as those in Example 1.

[Comparative Example 2]
In Comparative Example 2, preheating was performed for 10 seconds. The heating stage is initially set to 30 ° C., and the stage temperature is adjusted by the heating mechanism so that the anisotropic conductive film has a temperature profile of 75 ° C. 5 seconds after mounting the temporary connection body and 90 ° C. after 10 seconds. It was adjusted.

  The temperature profile of the preheating according to the comparative example 2 is as shown by the temperature gradient 3 in FIG. In Comparative Example 2, the temperature of the anisotropic conductive film was increased by 60 ° C. from 30 ° C. to 90 ° C. in 10 seconds by preheating. Then, when 50% of the total preheating time for 10 seconds had elapsed (after 5 seconds), the temperature was raised by 75% (45 ° C.) to the temperature raised by the stage heating (60 ° C.) to 75 ° C. After preheating, the main press bonding step was performed under the same conditions as in Example 1 to manufacture a connection body.

[Connected body evaluation method]
Measurement and evaluation methods of the pre-bonding reaction rate, warpage amount, and connection resistance value of the temporary connection bodies and connection bodies according to Examples and Comparative Examples are as follows.

[Measurement of reaction rate before final bonding]
An uncured anisotropic conductive film as sample A and an anisotropic conductive film taken out from the heating stage before the main pressure bonding step as sample B are sampled, and 10 mg of each sample is precisely weighed in a measurement cell. And each of these samples from the exothermic peak area when the temperature was raised from 30 ° C. to 230 ° C. at a heating rate of 10 ° C./min with a differential differential calorimeter DSC200 (model name, manufactured by Seiko Denshi Kogyo Co., Ltd.). Find the calorific value. In addition, the calorific value of each sample is set to A and B for convenience. Next, using these A and B, the DSC reaction rate R (%) immediately after heating and pressing was determined by the following formula 1.
R (%) = (1-B / A) × 100 (Formula 1)

[Measurement of warpage]
Using a stylus type surface roughness meter (trade name: SE-3H, manufactured by Kosaka Laboratory Co., Ltd.), the amount of warpage of the glass substrate surface for evaluation after scanning from the lower side of the glass substrate and the final bonding of the evaluation IC is performed. (Μm) was measured. A case where the amount of warpage was the same as or higher than that of Comparative Example 1 was evaluated.

  If the amount of warping is at the level of Comparative Example 1, uneven brightness occurs due to deformation of the transparent substrate of the liquid crystal display panel. On the other hand, if the level is ◯ or ◎, luminance unevenness hardly occurs.

[Measurement of connection resistance]
The connection resistance (Ω) after the environmental test (85 ° C./85%/500 hr) was measured using a digital multimeter (trade name: Digital Multimeter 7561, manufactured by Yokogawa Electric Corporation). When the resistance value including the connection portion between the bump and the wiring electrode is less than 10Ω, the resistance value is evaluated as “◯”, when the resistance value is 10Ω or more and less than 30Ω, and when it is 30Ω or more as “X”.

  As shown in Table 1, the connection bodies according to the respective examples had good warpage and connection resistance values. In each example, prior to the main press-bonding step by the thermocompression-bonding head, preheating is performed to heat the glass substrate for evaluation of the temporary connection body by stage heating, and the temperature profile is 50% of the total preheating time. This is because the temperature rising rate of the adhesive during the lapse of time is 50% or less of the total temperature rising temperature by the preheating.

  Thereby, the connection body according to each example can increase the temperature of the glass substrate for evaluation in the preheating, and can reduce the temperature difference from the evaluation IC heated and pressed by the thermocompression bonding head in the main pressure bonding step. The occurrence of warpage could be suppressed as compared with the connection body according to Comparative Example 1 in which no preheating was performed. Moreover, the connection body which concerns on each Example performed the preheating with the temperature profile like the temperature gradient 1 or 2, and the hardening reaction rate of the binder resin before this crimping | compression-bonding was suppressed to 22% or less low. Accordingly, in each example, the binder resin layer is prevented from being cured before the main pressure bonding, and in the main pressure bonding step, the binder resin is heated between the electrode terminal of the evaluation IC and the glass substrate for evaluation by heat pressing with a thermocompression bonding head. While flowing out from between the transparent electrodes, the conductive particles could be hardened in a crushed state, and the connection resistance value could be kept low even after the environmental test.

  On the other hand, in Comparative Example 1, since the main pressure bonding was performed without performing preheating, the connection resistance value was good, but when the temperature dropped to room temperature after the anisotropic conductive film was connected, Due to the temperature difference between the evaluation IC heated by the thermocompression bonding head and the evaluation glass substrate placed on the stage and the difference in thermal expansion coefficient between the binder and the evaluation glass substrate, the evaluation glass substrate Warping occurred.

  In Comparative Example 2, the temperature profile of the preheating was such that the temperature rising temperature of the adhesive when 50% of the total preheating time had elapsed was as high as 75% of the total temperature rising temperature due to stage heating. Although the amount of warpage of the glass substrate has been improved, the curing reaction rate of the binder resin before the main press bonding is as high as 32%, and the binder resin can be used as the electrode terminal of the IC for evaluation by heat pressing with a thermocompression bonding head in the main press bonding process. It was not possible to flow out from between the transparent electrodes of the glass substrate for evaluation, and the conductive particles could not be pushed in between both terminals, resulting in an increase in connection resistance.

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive film, 2 Release film, 3 Binder resin layer, 4 Conductive particle, 10 Liquid crystal display panel, 11, 12 Transparent substrate, 13 Seal, 14 Liquid crystal, 15 Panel display part, 16, 17 Transparent electrode, 17a Terminal part, 18 Liquid crystal driving IC, 20 COG mounting part, 21 Temporary connection body, 30 Connection device, 31 Stage, 32 Heating mechanism, 33 Thermocompression bonding head

Claims (7)

A temporary connection body in which electronic components are mounted on a substrate via an uncured adhesive is placed on a stage having a temperature control mechanism,
In the method of manufacturing a connection body in which the substrate side is heated by the stage, the electronic component is heated and pressed onto the substrate by a thermocompression bonding head, and the electronic component is connected to the substrate through the adhesive. ,
A method for manufacturing a connector, wherein the substrate is preheated by the stage prior to the heating and pressing step by the thermocompression bonding head.   The temperature increase rate of the adhesive at the time of 50% of the preheating time from the temporary connection body being placed on the stage to the heat pressing by the thermocompression bonding head is equal to the total temperature increase temperature due to the preheating. The manufacturing method of the connection body according to claim 1 which is 50% or less.   The temperature increase rate of the adhesive at the time of 50% of the preheating time from the temporary connection body being placed on the stage to the heat pressing by the thermocompression bonding head is equal to the total temperature increase temperature due to the preheating. The manufacturing method of the connection body according to claim 1 which is 25% or less.   The temperature profile of the adhesive between the time when the temporary connection body is placed on the stage and the time when the thermocompression bonding head is heated presses down a gradually rising profile. The manufacturing method of the connection body of description.   The method for manufacturing a connection body according to claim 1, wherein the substrate is a glass substrate, and the electronic component is an IC chip. A temporary connection body in which electronic components are mounted on a substrate via an uncured adhesive is placed on a stage having a temperature control mechanism,
In the connection method of heating the substrate side by the stage, heating and pressing the electronic component on the substrate by a thermocompression bonding head, and connecting the electronic component to the substrate through the adhesive,
A connection method in which the substrate is preheated by the stage prior to the heating and pressing step by the thermocompression bonding head.   The connection body manufactured by the method of any one of Claims 1-5.