JP2015170647A - Method of manufacturing connection body, connection method for electronic component, and connection body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate poor connection of an electrode terminal by preventing warping of an electronic component.SOLUTION: In a method of manufacturing a connection body, an electronic component which has bumps separately provided on one side of paired opposed side edges and the another side thereof, is arranged on a circuit board via an adhesive film, and pressure-bonded to the circuit board by a pressure-bonding tool. The adhesive film causes hardening reaction in an area where a section between the bumps of the electronic component is prearranged, before the electronic component is pressure-bonded by the pressure-bonding tool.

Description

  The present invention relates to a method for manufacturing a connection body in which an electronic component and a circuit board are connected, and in particular, a method for manufacturing a connection body in which the electronic component is connected to a circuit board by pressurizing the electronic component through an adhesive film, The present invention relates to an electronic component connection method and a connection body manufactured thereby.

  2. Description of the Related Art Conventionally, a connection body is provided in which electronic components such as an IC chip and an LSI chip are connected to circuit boards of various electronic devices. In recent years, various electronic devices use IC chips or LSI chips in which bumps, which are protruding electrodes, are arranged on the mounting surface as electronic components from the viewpoints of fine pitch, light weight, and thinning. So-called COB (chip on board) or COG (chip on glass) for directly mounting electronic components on the circuit board is employed.

  In COB connection and COG connection, an IC chip is thermocompression-bonded on a terminal portion of a circuit board via an anisotropic conductive film. An anisotropic conductive film is a film formed by mixing conductive particles in a thermosetting binder resin, and heat conduction is performed between two conductors so that electrical conduction between the conductors is achieved with the conductive particles. The mechanical connection between the conductors is maintained by the binder resin. As an adhesive constituting the anisotropic conductive film, a highly reliable thermosetting adhesive is usually used. In addition, a connection method using a photo-curing resin or a connection method using both thermosetting and photo-curing is also used.

  For example, as shown in FIG. 8A, the bumped IC chip 50 has an input bump area 52 in which input bumps 51 are arranged in a line along one side edge 50a on the mounting surface of the circuit board. An output bump area 54 in which output bumps 53 are arranged in two rows in a zigzag manner is provided along the other side edge 50b facing one side edge 50a. The bump arrangement varies depending on the type of IC chip. In general, a conventional IC chip with bumps has a larger number of output bumps 53 than the number of input bumps 51, and an output bump area 54 than the area of the input bump area 52. And the shape of the input bump 51 is formed larger than the shape of the output bump 53.

  In COG mounting, as shown in FIG. 8B, after the IC chip 50 is mounted on the electrode terminal 57 of the circuit board 56 via the anisotropic conductive film 55, the IC chip is mounted by the thermocompression bonding head 58. Heat and press from above 50. By the heat and pressure by the thermocompression bonding head 58, the binder resin of the anisotropic conductive film 55 is melted and flows from between the input / output bumps 51 and 53 and the electrode terminals 57 of the circuit board 56, and each input / output. Conductive particles are sandwiched between the bumps 51 and 53 and the electrode terminal 57 of the circuit board 56, and in this state, the binder resin is thermally cured. As a result, the IC chip 50 is electrically and mechanically connected to the circuit board 56.

JP2013-155286A

  Here, an electronic component such as an IC chip 50 with bumps is separated by forming an input bump 51 on one side of a pair of opposing side edges and forming an output bump 53 on the other side, and bumps in the center. There is a region where is not formed.

  Further, the IC chip 50 is different in bump arrangement and size between the input bump 51 and the output bump 53 and is asymmetrically arranged on the mounting surface. For example, in an IC chip such as a driving IC used for various liquid crystal display panels such as smartphones, as the number of pixels increases, output signals corresponding to each pixel increase, and output bumps tend to increase. There has also been proposed a design in which the input bumps 51 formed on the side edge are arranged in one row while the output bumps 53 formed on the other side edge are arranged in two rows or three or more rows.

  Furthermore, as mobile devices such as smartphones, tablet devices, and wearable devices have become smaller and thinner in recent years, the IC chip 50 is also designed to be wider and thinner, increasing the area between the input and output bumps, and pressing in the surface direction. On the other hand, the area between the bumps is easily deformed.

  For this reason, when the IC chip 50 is heated and pressed by the thermocompression bonding head 58 when connected to the circuit board 56, the binder resin is eliminated in the central inter-bump region where the input bump 51 and the output bump 53 are not formed. Advance and bend. As a result, the IC chip 50 is in a state where the outside of the input bumps 51 and the output bumps 53 formed on the side edge of the substrate is floated, the pressing force is weakened, and there is a possibility that connection failure occurs.

  Further, as shown in FIG. 9, in the IC chip 50, when the central portion where the input bump 51 and the output bump 53 are not formed is bent, the pressure is concentrated on the bump 53a formed on the inner side in the output bump 53. Relatively, the pressing force to the conductive particles 60 by the bumps 53b formed on the outside is weakened, resulting in poor connection. Further, when the heat pressing by the crimping head 58 is finished and pressed out, the circuit board 56 and the IC chip 50 are warped due to the difference in contraction rate caused by the difference in linear expansion coefficient between the circuit board 56 and the IC chip 50. Relatively, the pressing force to the conductive particles 60 by the bumps 53b formed on the outside is weakened, resulting in poor connection.

  Then, an object of this invention is to provide the manufacturing method of the connection body which can prevent the curvature of an electronic component, and can eliminate the connection defect of an electrode terminal, the connection method of an electronic component, and a connection body.

  In order to solve the above-described problem, a manufacturing method of a connection body according to the present invention is an electronic component in which bumps are provided separately on one side and the other side of a pair of opposing side edges via an adhesive film. In the method of manufacturing a connection body, which is arranged on a circuit board and the electronic component is crimped to the circuit board by a crimping tool, the adhesive film is preliminarily bonded to the electronic component before the electronic component is crimped by the crimping tool. A curing reaction is caused in a region where the bumps are arranged.

  Further, the electronic component connecting method according to the present invention is such that an electronic component provided with bumps on one side and the other side of a pair of opposing side edges is disposed on a circuit board via an adhesive film, and is crimped. In the electronic component connecting method in which the electronic component is crimped to the circuit board by a tool, the adhesive film is disposed between the bumps of the electronic component in advance before the electronic component is crimped by the crimping tool. It causes a curing reaction in the region.

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

  According to the present invention, since the adhesive film causes a curing reaction in a region where the bumps of the electronic component are arranged in advance, the electronic component being heated and pressed is prevented from being bent and arranged along both side edges. It is possible to prevent the bumps from floating and to prevent the connection resistance from increasing.

FIG. 1 is a cross-sectional view showing a manufacturing process of a connection body to which the present invention is applied. FIG. 2 is a cross-sectional view showing a manufacturing process of a connection body to which the present invention is applied. FIG. 3 is a plan view showing a mounting surface of the liquid crystal driving IC. FIG. 4 is a cross-sectional view of the anisotropic conductive film. FIG. 5 is a plan view of the anisotropic conductive film. FIG. 6 is a cross-sectional view showing a manufacturing process of a connection body to which the present invention is applied. FIG. 7 is a cross-sectional view showing a step of allowing the anisotropic conductive film to advance a curing reaction in advance. (A) is a top view of liquid crystal drive IC, (B) is sectional drawing which shows a connection process. FIG. 9 is a cross-sectional view showing a state in which the liquid crystal driving IC is warped.

  Hereinafter, a method for manufacturing a connection body, a method for connecting an electronic component, 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.

[LCD panel]
Hereinafter, a liquid crystal display panel in which an IC chip for driving a liquid crystal as an electronic component is mounted on a glass substrate will be described as an example of a connection body to which the present invention is applied. 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. The COG mounting portion 20 is formed with a substrate-side alignment mark 21 that overlaps the terminal portion 17 a of the transparent electrode 17 and the IC-side alignment mark 22 provided on the liquid crystal driving IC 18.

  The liquid crystal driving IC 18 can selectively apply a liquid crystal driving voltage to the pixels to change the alignment of the liquid crystal partially and perform a predetermined liquid crystal display. As shown in FIG. 2, the liquid crystal driving IC 18 has a plurality of electrode terminals 19 (bumps) that are electrically connected to the terminal portions 17 a of the transparent electrode 17 on the mounting surface 18 a to the transparent substrate 12. . As the electrode terminal 19, for example, a copper bump, a gold bump, or a copper bump plated with gold is suitably used.

[Electrode terminal]
For example, as shown in FIG. 3, the liquid crystal driving IC 18 has electrode terminals 19a (input bumps) arranged in a line along one side edge of the mounting surface 18a, and the other side edge facing one side edge. The electrode terminals 19b (output bumps) are arranged in a staggered manner in a plurality of rows along the line, and there is an inter-terminal region A where no electrode terminals are provided between the electrode terminals 19a and 19b. The electrode terminals 19a and 19b and the terminal portions 17a provided on the COG mounting portion 20 of the transparent substrate 12 are formed at the same number and pitch, respectively, and the transparent substrate 12 and the liquid crystal driving IC 18 are aligned. Connected by connecting.

  In addition to the arrangement shown in FIG. 3, the electrode terminals 19a and 19b may be arranged in one or more rows on one side edge and in one or more rows on the other side edge. May be. In addition, the electrode terminals 19a and 19b may have a plurality of rows arranged in a row, and a portion of the rows may be arranged in a row. Further, the electrode terminals 19a and 19b may be formed in a straight arrangement in which a plurality of rows are parallel and adjacent electrode terminals are parallel, or a plurality of rows of parallel and adjacent electrode terminals are equal. It may be formed in a staggered arrangement. In the present specification, when it is not necessary to distinguish between the electrode terminals 19a constituting the input bumps and the electrode terminals 19b constituting the output bumps, they are simply referred to as electrode terminals 19.

  Further, the liquid crystal driving IC 18 is formed with an IC side alignment mark 22 for alignment with the transparent substrate 12 by being superimposed on the mounting surface 18a with the substrate side alignment mark 21 (see FIG. 2). Since the wiring pitch of the transparent electrodes 17 of the transparent substrate 12 and the fine pitch of the electrode terminals 19 of the liquid crystal driving IC 18 are increasing, the liquid crystal driving IC 18 and the transparent substrate 12 are required to have high-precision alignment adjustment. It has been.

  As the substrate-side alignment mark 21 and the IC-side alignment mark 22, various marks that can be aligned with the transparent substrate 12 and the liquid crystal driving IC 18 can be used.

  On the terminal part 17a of the transparent electrode 17 formed in the COG mounting part 20, a liquid crystal driving IC 18 is connected using the anisotropic conductive film 1 as an adhesive film for circuit connection. The anisotropic conductive film 1 contains conductive particles 4, and the electrode terminal 19 of the liquid crystal driving IC 18 and the terminal portion 17 a of the transparent electrode 17 formed on the edge portion 12 a of the transparent substrate 12 are electrically conductive. Electrical connection is made through the particles 4. The anisotropic conductive film 1 is thermocompression bonded by the thermocompression bonding head 33, whereby the binder resin is fluidized and the conductive particles 4 are crushed between the terminal portion 17a and the electrode terminal 19 of the liquid crystal 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. 4, 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. The anisotropic conductive film 1 is a thermosetting adhesive or a photo-curing adhesive such as ultraviolet rays, and is attached to the transparent electrode 17 formed on the transparent substrate 12 of the liquid crystal display panel 10 and also has a liquid crystal driving IC 18. Is mounted and is fluidized by being thermally pressed by the thermocompression bonding head 33, and the conductive particles 4 are crushed between the terminal portion 17a of the transparent electrode 17 and the electrode terminal 19 of the liquid crystal driving IC 18 facing each other. The conductive particles are cured in a crushed state by heating or ultraviolet irradiation. Thereby, the anisotropic conductive film 1 can connect the transparent substrate 12 and the liquid crystal driving IC 18 to make them conductive.

  In the anisotropic conductive film 1, conductive particles 4 are dispersed in a normal binder resin layer 3 containing a film-forming resin, a curable resin, a latent curing agent, a silane coupling agent, and the like.

  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.

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

  It does not specifically limit as curable resin, For example, a commercially available epoxy resin, an acrylic resin, etc. are mentioned.

  The epoxy resin is not particularly limited. 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, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as an acrylic resin, According to the objective, an acrylic compound, liquid acrylate, etc. can be selected suitably. For example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane 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, tricyclo Examples include decanyl acrylate, tris (acryloxyethyl) isocyanurate, urethane acrylate, and epoxy acrylate. In addition, what made acrylate the methacrylate can also be used. These may be used individually by 1 type and may use 2 or more types together.

  The latent curing agent is not particularly limited, and examples thereof include various curing agents such as a heat curing type and a UV curing type. The latent curing agent does not normally react, but is activated by various triggers selected according to applications such as heat, light, and pressure, and starts the reaction. The activation method of the thermal activation type latent curing agent includes a method of generating active species (cation, anion, radical) by a dissociation reaction by heating, etc., and it is stably dispersed in the epoxy resin near room temperature, and epoxy at high temperature There are a method of initiating a curing reaction by dissolving and dissolving with a resin, a method of initiating a curing reaction by eluting a molecular sieve encapsulated type curing agent at a high temperature, and an elution / curing method using microcapsules. 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.

  Although it does not specifically limit as a silane coupling agent, For example, an epoxy type, an amino type, a mercapto sulfide type, a ureido type etc. can be mentioned. By adding the silane coupling agent, the adhesion at the interface between the organic material and the inorganic material is improved.

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

[Conductive particles]
Examples of the conductive particles 4 include any known conductive particles used in the anisotropic conductive film 1. Examples of the conductive particles 4 include particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver, gold, metal oxide, carbon, graphite, glass, ceramic, Examples thereof include those in which the surface of particles such as plastic is coated with metal, or those in which the surface of these particles is further coated with an insulating thin film. In the case where the surface of the resin particle is coated with metal, examples of the resin particle include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile / styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, and the like. Can be mentioned.

  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 curable resin, a latent curing agent, a silane coupling agent, conductive particles and the like is prepared. The adjusted adhesive composition is applied onto the release film 2 using a bar coater, a coating device, etc., dried by an oven or the like, and finally the cover film 6 is laminated, whereby the binder resin layer 3 is formed on the release film 2. A supported anisotropic conductive film 1 is obtained.

[Precuring]
Between the electrode terminals 19a and 19b of the liquid crystal drive IC 18 before the liquid crystal drive IC 18 is pressure-bonded by the thermocompression bonding head 33 described later, the anisotropic conductive film 1 is a terminal region A in which no electrode terminals are provided. A curing reaction is caused in advance in the region where the is disposed. As shown in FIG. 3, when the mounting surface 18 a of the liquid crystal driving IC 18 is formed in a rectangular shape whose longitudinal direction is the arrangement direction of the electrode terminals 19, the anisotropic conductive film 1 also has the longitudinal direction of the liquid crystal driving IC 18. Affixed along the direction. At this time, as shown in FIG. 5, the anisotropic conductive film 1 is a precured portion in which a curing reaction has been generated in the vicinity of the approximate center in the width direction disposed in the inter-terminal region A of the liquid crystal driving IC 18. 5 is formed.

  Therefore, in the anisotropic conductive film 1, when the liquid crystal driving IC 18 is disposed in the COG mounting portion 20, the inter-terminal region A of the liquid crystal driving IC 18 is provided on the precuring portion 5 as shown in FIG. 6. . The preliminary curing unit 5 has a high viscosity of the binder resin because the curing reaction has progressed, and even when the liquid crystal driving IC 18 is heated and pressed by the thermocompression bonding head 33, the discharge from the inter-terminal region A is suppressed. . Therefore, the anisotropic conductive film 1 prevents the bending of the liquid crystal driving IC 18 that is heated and pressed against the thermocompression bonding head 33 by the precuring portion 5, and the electrode terminal portions 19a and 19b arranged along both side edges. Can be prevented, and an increase in connection resistance due to insufficient pressing of the conductive particles 4 can be prevented.

[Curing reaction rate]
Here, the curing reaction rate of the precured portion 5 is preferably 10 to 30%. When the curing reaction rate is less than 10%, the warp of the liquid crystal driving IC 18 cannot be sufficiently suppressed, and the electrode terminal 19b on the side edge side floats, and the insufficient pressing of the conductive particles 4 is sufficiently solved. There is a risk that it will not be possible. If the curing reaction rate exceeds 30%, the flow of the binder resin of the anisotropic conductive film 1 is hindered when the liquid crystal driving IC 18 is crimped, and the binder resin is excluded from between the electrode terminal 19 and the terminal portion 17a. Otherwise, the pushing of the conductive particles 4 is insufficient, and the conduction resistance may increase.

[Pre-curing]
When the thermosetting binder resin layer 3 is used, the anisotropic conductive film 1 can be cured by heating in the vicinity of the substantial center in the width direction in advance. For example, as shown in FIG. 7, the preliminary curing is performed by heating and pressing from above the cover film 6 with a thermocompression bonding tool 7 having a width W corresponding to the width of the preliminary curing portion 5 of the anisotropic conductive film 1. .

  In addition to pre-curing with the thermocompression bonding tool 7, the pre-curing is performed by irradiating infrared rays through a slit corresponding to the pre-curing width to heat the vicinity of the center of the binder resin layer 15 in the width direction to perform a curing reaction. You may start. Or you may squeeze to the width | variety according to the width | variety which pre-cures infrared light, and may irradiate to the approximate center of the width direction of the binder resin layer 15 directly.

[Advanced photocuring]
Further, when the photocurable binder resin layer 3 is used, the anisotropic conductive film 1 irradiates ultraviolet light near the substantial center in the width direction of the binder resin layer 15 through a slit corresponding to the width to be precured. The curing reaction may be initiated by this. Or you may restrict | squeeze to the width | variety according to the width | variety which pre-cures ultraviolet light, and may irradiate to the approximate center of the width direction of the binder resin layer 15 directly.

  The preliminary curing of the anisotropic conductive film 1 is preferably heat curing. According to photocuring, it can be cured only from the surface of the binder resin layer 15 to a very shallow depth. On the other hand, according to thermosetting, the curing reaction can proceed deeply in the thickness direction from the surface of the binder resin layer 15 due to the heat transfer effect, and the curing reaction is surely generated over the entire area in the thickness direction of the preliminary curing portion 5. Can be made.

[2-layer ACF]
The anisotropic conductive film 1 according to the present invention includes a binder resin layer 3 containing conductive particles 4 and an insulating adhesive layer made of an insulating adhesive composition that does not contain conductive particles. 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 comprises a normal binder component containing a film-forming resin, a curable resin, a latent curing agent, a silane coupling agent, etc., and the binder resin layer described above 3 can be made of the same material as the adhesive composition of No. 3.

  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.

  The shape of the anisotropic conductive film 1 is not particularly limited. For example, as shown in FIG. 4, the shape of the anisotropic conductive film 1 is a long tape shape that can be wound around the take-up reel 8, and is cut by a predetermined length. Can be used.

  Moreover, although the above-mentioned embodiment demonstrated as an example the anisotropic conductive film 1 which shape | molded the thermosetting resin composition containing the electroconductive particle 4 in the film form as an adhesive film, the adhesion | attachment which concerns on this invention An agent is not limited to this, For example, the insulating adhesive film using the binder resin layer 3 which does not contain the electroconductive particle 4 may be sufficient.

[Connecting device]
Next, a connection device for connecting the liquid crystal driving IC 18 to the transparent substrate 12 will be described. 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 transparent substrate 12 on which the liquid crystal driving IC 18 is temporarily mounted is placed via the anisotropic conductive film 1, and the transparent substrate 12 placed on the stage 31 via the anisotropic conductive film 1. It has a thermocompression bonding head 33 that heats and presses the mounted liquid crystal driving IC 18, 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.

  The stage 31 may be auxiliary heated to a temperature (for example, 80 to 100 ° C.) that does not cure the binder resin layer 3 by a heating mechanism (not shown) 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 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 temperature. Further, the thermocompression bonding head 33 is held by the head moving mechanism 34 so that the thermocompression bonding head 33 can be moved close to and away from the stage 31 and the pressing force applied to the liquid crystal driving IC 18 can be adjusted.

  When the liquid crystal driving IC 18 is connected, the thermocompression bonding head 33 heats and presses the liquid crystal driving IC 18 against the transparent substrate 12 at a predetermined temperature, pressure, and time by the head moving mechanism 34. 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 between the terminal portion 17 a of the transparent electrode 17 and the electrode terminal 19 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 next heating and pressing process.

[Connection process]
Next, a connection process for connecting the liquid crystal driving IC 18 to the transparent substrate 12 will be described. In the connecting step, first, the anisotropic conductive film 1 is temporarily pasted on the COG mounting part 20 on which the terminal part 17a of the transparent substrate 12 is formed. The anisotropic conductive film 1 has a region A between terminals of the liquid crystal driving IC 18 of the binder resin layer 15 in advance before the liquid crystal driving IC 18 is mounted before or after being temporarily pasted on the COG mounting portion 20. A precured portion 5 in which a curing reaction is caused by heating or ultraviolet irradiation is formed in the region to be disposed. After the anisotropic conductive film 1 is temporarily attached on the COG mounting portion 20, the release film 2 is peeled off, so that only the binder resin layer 15 is attached.

  Next, the liquid crystal driving IC 18 is mounted on the COG mounting portion 20 of the transparent substrate 12 via the anisotropic conductive film 1, and the transparent substrate 12 is mounted on the stage 31 of the connection device 30. Thus, the liquid crystal driving IC 18 is opposed to the thermocompression bonding head 33 that stands by above the stage 31.

  Next, the thermocompression bonding head 33 heated to a predetermined temperature for curing the binder resin layer 3 is hot-pressed from above the liquid crystal driving IC 18 at a predetermined pressure and time. Thereby, the binder resin layer 3 of the anisotropic conductive film 1 exhibits fluidity, and flows out from between the mounting surface 18a of the liquid crystal driving IC 18 and the COG mounting portion 20 of the transparent substrate 12, and in the binder resin layer 3. The conductive particles 4 are sandwiched and crushed between the electrode terminals 19 of the liquid crystal driving IC 18 and the terminal portions 17a of the transparent substrate 12, and in this state, the binder resin heated by the thermocompression bonding head 33 is cured.

  At this time, in the connection step according to the present invention, since the curing reaction is advanced in advance in the binder resin layer 3 below the inter-terminal region A of the liquid crystal driving IC 18, the liquid crystal driving IC 18 is heated and pressed by the thermocompression bonding head 33. Also when it is done, discharge from the inter-terminal region A is suppressed.

  Therefore, according to this connection process, as shown in FIG. 6, the precured portion 5 of the anisotropic conductive film 1 prevents the liquid crystal driving IC 18 being heated and pressed against the thermocompression bonding head 33 from being bent. It is possible to prevent the electrode terminal portions 19 a and 19 b arranged along the edge from floating and to prevent an increase in connection resistance due to insufficient pressing of the conductive particles 4.

  Further, according to the present connection step, since the curing reaction is advanced in advance in the binder resin layer 3 below the inter-terminal region A of the liquid crystal driving IC 18, the inter-terminal region of the liquid crystal driving IC 18 accompanying the curing shrinkage of the binder resin. The occurrence of warping of A can be suppressed, and even after the heating and pressing of the thermocompression bonding head 33, the spring back due to the residual stress of the liquid crystal driving IC 18 is prevented, and the connectivity between the terminal portion 17a and the electrode terminal 19 is prevented. Can be maintained.

  The electrode terminal 19 and the terminal part 17a are electrically connected by sandwiching the conductive particles 4. Thereby, the liquid crystal display panel 10 in which electrical conductivity is ensured between the electrode terminal 19 of the liquid crystal driving IC 18 and the terminal portion 17a formed on the transparent substrate 12 can be manufactured.

  The conductive particles 4 that are not between the electrode terminals 19 and the terminal portions 17a are dispersed in the binder resin in the inter-terminal spaces between the adjacent electrode terminals 19, and maintain an electrically insulated state. Thereby, electrical conduction is achieved only between the electrode terminal 19 of the liquid crystal driving IC 18 and the terminal portion 17a of the transparent substrate 12. In addition, by using a fast curing type radical polymerization reaction system as the binder resin, the binder resin can be rapidly cured even with a short heating time. Further, the anisotropic conductive film 1 is not limited to the thermosetting type, and may be a photo-curing type or a photo-heat combined type adhesive as long as pressure connection is performed.

  Next, examples of the present invention will be described. In this example, a connected body sample in which an evaluation IC is connected to an evaluation glass substrate using an anisotropic conductive film is prepared, and the conductive material sandwiched between the bump of the evaluation IC and the terminal portion of the evaluation glass substrate. The height of the conductive particles and the conduction resistance value after the reliability test were measured.

[Anisotropic conductive film]
The anisotropic conductive film used for connecting the IC for evaluation was 60 parts by mass of phenoxy resin (trade name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.), 40 parts by mass of epoxy resin (trade name: EP828, manufactured by Japan Epoxy Resin Co., Ltd.). , 1 part by mass of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 4 parts by mass of a thermal cationic curing agent (trade name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), conductive particles (Trade name: Micropearl AU, particle size 3 μm, manufactured by Sekisui Chemical Co., Ltd.) was adjusted to a binder resin composition added to toluene, and this binder resin composition was applied onto a release film (PET), followed by 70 ° C. It was formed by leaving it in hot air for 10 minutes and drying it. The anisotropic conductive film has a width of 2.5 mm, and the binder resin layer after drying has a thickness of 18 μm.

[IC for evaluation]
As an evaluation element for measuring the conduction resistance, an IC substrate having a width of 2.0 mm × a length of 24 mm and a thickness of 0.20 mm is provided, and a plurality of output bumps are arranged in two rows along a side edge on one long side. An evaluation IC was prepared, in which a plurality of input bumps were formed in a single-line straight arrangement along the other long side edge opposite to the one long side edge. The input bump size is 40 μm × 120 μm, and the output bump size is 14 μm × 120 μm. The width of the inter-terminal region between the input bump and the output bump is 1.5 mm.

[Evaluation Glass Substrate]
As an evaluation glass substrate to which the evaluation IC is connected, an ITO pattern glass having a comb-like electrode pattern having a thickness of 0.1 mm and the same size and the same pitch as the bump of the evaluation IC was used.

  After temporarily attaching an anisotropic conductive film to the glass substrate for evaluation, the IC for evaluation was mounted while aligning the IC bump and the substrate electrode, and heat was applied by a thermocompression bonding head at 170 ° C., pressure 60 MPa, and 5 sec. A connector sample was prepared by pressure bonding. About each created connection body sample, the cross section of the connection body sample was measured with the electron microscope (SEM) about the height of the electroconductive particle pinched by the output bump of evaluation IC, and the terminal part of the glass substrate for evaluation. . The measurement was performed on the conductive particles under each output bump in the first row arranged outside the one long side of the IC substrate and in the second row arranged inside. The smaller the difference between the heights of the conductive particles in the output bumps in the first row and the second row, the more uniformly the conductive particles are pressed, that is, the warpage of the evaluation IC is suppressed. is there.

  Moreover, about the output bump of the 1st row | line | column of each connection body sample, the conduction resistance after a reliability test was measured using the digital multimeter (brand name: Digital multimeter 7561, Yokogawa Electric Corporation make). The conditions of the reliability test are 85 ° C., 85% RH, and 500 hr. In the evaluation of the resistance value, the initial value: less than 10Ω is ◯ (best), the initial value: 10Ω or more and less than 30Ω is Δ (normal), and 30Ω or more is × (defect).

[Example 1]
In Example 1, before adhering the anisotropic conductive film to the glass substrate for evaluation, an area between the input bumps and the output bumps of the evaluation IC between which the terminals are not provided is arranged in advance. A curing reaction was caused. This pre-curing was performed by heating and pressing the anisotropic conductive film with a thermocompression tool (SUS cartridge heater) having a width of 0.5 mm (see FIG. 7). The heat pressing conditions of the thermocompression bonding tool were 1.0 MPa, 130 ° C., and 3 seconds. The temperature of the thermocompression bonding tool was measured by providing a thermocouple at the tip.

  The curing reaction rate of the precured portion of the anisotropic conductive film according to Example 1 was measured and found to be 8%. For the measurement of the curing reaction rate, the pre-cured part with which the thermocompression bonding tool is in contact is cut out with a cutter, and temporarily attached to a glass substrate for evaluation using an infrared spectrophotometer (FT / IR-4100, manufactured by JASCO Corporation). It was calculated from the attenuation amount (%) of the absorption wavelength of the epoxy ring before and after connection of the evaluation IC.

  In the connection body sample according to Example 1, the conductive particle height in the first row of output bumps is 2.7 μm, and the conductive particle height in the second row of output bumps is 2.2 μm. The evaluation of the conduction resistance was Δ (normal).

[Example 2]
In Example 2, the same conditions as in Example 1 were used except that the heating temperature of the thermocompression bonding tool was set to 140 ° C. The curing reaction rate of the precured portion of the anisotropic conductive film according to Example 2 was measured and found to be 16%.

  In the connection body sample according to Example 2, the conductive particle height in the first row of output bumps is 2.3 μm, and the conductive particle height in the second row of output bumps is 2.2 μm. The evaluation of the conduction resistance was ◯ (best).

[Example 3]
In Example 3, the same conditions as in Example 1 were used except that the heating temperature of the thermocompression bonding tool was set to 150 ° C. The curing reaction rate of the precured portion of the anisotropic conductive film according to Example 3 was measured and found to be 27%.

  In the connection body sample according to Example 3, the conductive particle height in the first row of output bumps is 2.2 μm, and the conductive particle height in the second row of output bumps is 2.2 μm. The evaluation of the conduction resistance was ◯ (best).

[Example 4]
In Example 4, the same conditions as in Example 1 were used except that the heating temperature of the thermocompression bonding tool was set to 160 ° C. The curing reaction rate of the precured portion of the anisotropic conductive film according to Example 4 was measured and found to be 41%.

  In the connection body sample according to Example 4, the conductive particle height in the first row of output bumps is 2.4 μm, and the conductive particle height in the second row of output bumps is 2.4 μm. The evaluation of the conduction resistance was Δ (normal).

[Comparative Example 1]
In Comparative Example 1, preliminary curing for the anisotropic conductive film was not performed.

  In the connection body sample according to Comparative Example 1, the conductive particle height in the first row of output bumps was 2.9 μm, and the conductive particle height in the second row of output bumps was 2.2 μm. The conduction resistance was evaluated as x (defect).

  As shown in Table 1, in the connection body samples according to Examples 1 to 4, the difference in height of the conductive particles under each output bump in the first row and the second row is 0.5 μm or less, and evaluation It can be seen that the warpage of the IC is suppressed. This is because the curing reaction is allowed to proceed in advance in the region arranged in the inter-terminal region of the evaluation IC, thereby suppressing the discharge of the binder resin under the inter-terminal region when the evaluation IC is connected, and the viscosity of This is because bending of the evaluation IC is suppressed by a high pre-cured portion.

  On the other hand, in Comparative Example 1, the bending of the binder resin in the inter-terminal region of the evaluation IC is caused to bend, and the output bumps in the first row arranged outside the evaluation IC are in a floating state. The difference from the height of the conductive particles in the output bump in the second row expanded to 0.7 μm. Further, the conductive particles themselves are not sufficiently pressed in the output bumps in the first row. Therefore, in Comparative Example 1, the evaluation of the conduction resistance after the reliability test in the first column was x (defect).

  In Example 2 and Example 3, there was no difference in the height of the conductive particles under each output bump in the first row and the second row, and the evaluation of the conduction resistance after the reliability test was also ◯ (best). . On the other hand, in Example 1, although the curing reaction rate of the precured portion is slightly low at 8% and there is no problem in actual use, the height of the conductive particles in the output bumps in the first row is increased, and the evaluation IC Suppression of warpage was slightly reduced. Further, in Example 4, the curing reaction rate of the precured part is slightly high at 41%, and the discharge of the binder resin is suppressed as compared with Examples 1 to 3, and although there is no problem in actual use, the conduction resistance value is Slightly higher. From this, it can be seen that the optimal curing reaction rate of the precured portion is 10 to 30%.

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive film, 2 Release film, 3 Binder resin layer, 4 Conductive particle, 5 Pre-hardening part, 6 Cover film, 7 Thermocompression bonding tool, 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, 30 Connection device, 31 Stage, 33 Thermocompression bonding head, 34 Head moving mechanism

Claims (7)

Electronic components provided with bumps on one side and the other side of a pair of opposing side edges are arranged on a circuit board via an adhesive film,
In the manufacturing method of the connection body for crimping the electronic component to the circuit board with a crimping tool,
The said adhesive film is a manufacturing method of the connection body which produces a hardening reaction in the area | region where the said bumps of the said electronic component are arrange | positioned previously, before the said electronic component is crimped | bonded by the said crimping tool.   The said adhesive film is a manufacturing method of the connection body of Claim 1 which produces a curing reaction in the center part of the width direction.   The method for producing a connection body according to claim 1 or 2, wherein the curing reaction of the adhesive film has a curing reaction rate of 10 to 30%.   The manufacturing method of the connection body of any one of Claims 1-3 which produce the said hardening reaction by heating the said adhesive film.   The manufacturing method of the connection body of any one of Claims 1-3 which produce the said hardening reaction by irradiating light to the said adhesive film.   The connection body manufactured by the method of any one of Claims 1-5. Electronic components provided with bumps on one side and the other side of a pair of opposing side edges are arranged on a circuit board via an adhesive film,
In the method for connecting electronic components, in which the electronic component is crimped to the circuit board by a crimping tool,
The adhesive film is a connection method for an electronic component in which a curing reaction is caused in a region where the bumps of the electronic component are arranged in advance before the electronic component is crimped by the crimping tool.

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