JP2006049783A - Manufacturing method and electrode connection method for anisotropic conductive adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an anisotropic conductive adhesive film that can scatter and form a dense region (6) of electrically conductive particles (5) without directly contacting a sticky adhesive layer (4), and an electrode connection method using an anisotropic conductive adhesive agent. <P>SOLUTION: The method is to use the ink-jet method to jet ink (3) containing electro-conductive particles (5) from a jet nozzle (10) onto an adhesive resinous film (2) or an adhesive layer (4), thus scattering and forming a dense region (6) of conductive particles (5) smaller than a minimum insulation distance d between connection electrodes (20) or connected electrodes (21) whose maximum outside diameter A of the region (6) is adjacent to the adhesive resinous film (2) or the adhesive layer (4) at least in an arrangement direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing an anisotropic conductive film used for electrical connection between electronic components arranged at a narrow pitch and connection electrodes of a circuit board, and connection electrodes and circuits of electronic components arranged at a narrow pitch. The present invention relates to an electrode connection method for connecting electrodes to be connected between substrates using an anisotropic conductive adhesive.

  In recent years, with the miniaturization of electronic components, the electrodes have become finer and narrower and a high-resolution connection method is required. Also, from the viewpoint of protecting the natural environment, a connection method that replaces lead-based solder is also required. Attention has been focused on connection using a conductive conductive adhesive film or an anisotropic conductive adhesive.

  In this connection method, an anisotropic conductive adhesive film or an anisotropic conductive adhesive is interposed between the connection electrode of the opposing electronic component and the connection electrode of the circuit board, and the connection electrode and the connection electrode are heated and pressurized. In the pressing direction, the electrodes are electrically connected via the conductive particles contained in the anisotropic conductive adhesive film or the anisotropic conductive adhesive, and the connection electrode or the connected electrode orthogonal to the pressing direction is connected. In the arrangement direction, the insulation between the electrodes is maintained by making the outer diameter of the conductive particles smaller than the insulation interval between the adjacent electrodes.

  These conductive particles are blended so as to be uniformly dispersed in a binder such as an epoxy resin, but when the insulating interval between adjacent electrodes is a very small interval of about 10 μm, a plurality of aggregated conductive particles are electroded. There arises a problem that electrical conduction is established between them and insulation failure occurs. On the other hand, when the blending density of the conductive particles is reduced, the number of conductive particles interposed between the connecting electrode in the pressing direction and the connected electrode electrode is also reduced, resulting in a problem that connection reliability cannot be obtained.

  Therefore, in order to solve this problem, a method for producing an anisotropic conductive adhesive film in which a dense region of conductive particles is transferred and fixed on an adhesive film by a metal mask or gravure printing has been known (patent). Reference 1).

  For the same purpose, a method for producing an anisotropic conductive adhesive film in which a part of a photosensitive drum is charged, conductive particles are adsorbed on the charged part to form a dense region, and transferred onto a resin film is known. (See Patent Document 2).

  Furthermore, for the same purpose, an anisotropic conductive adhesive film manufacturing method is known in which one conductive particle is disposed in each of a plurality of through holes of a core film and the conductive particles are reliably dispersed (patent) Reference 3).

Japanese Patent No. 3472987 (page 3, column 5, lines 1 to 23, FIG. 2) Japanese Patent Laid-Open No. 3-8213 (page 2, column 1, line 10 to line 17, FIG. 1) JP 2003-13021 A (2nd page, third column, lines 37 to 46, FIG. 1)

  However, in the manufacturing method of Patent Document 1 in which dense regions are dispersedly arranged on a binder by metal mask or gravure printing, it is necessary to remove the binder after adhering the metal mask or gravure roll to the adhesive binder. There is a problem that a part of the film remains attached to the metal mask or the gravure roll, and the thickness of the binder becomes non-uniform along the longitudinal direction of the film.

  Moreover, even in the manufacturing method of Patent Document 2 in which the photosensitive drum is charged and the conductive particles are adsorbed, the adhesive binder and the photosensitive drum are brought into close contact with each other, and it is similarly difficult to separate the binder from the photosensitive drum. Is.

  Moreover, in the manufacturing method of Patent Document 3 in which conductive particles are accommodated in and dispersed in a plurality of through holes of the core film, it is difficult to accommodate the conductive particles without passing through each through hole, and an extra core film Therefore, the cost is increased and the thickness of the anisotropic conductive adhesive film is increased.

  Furthermore, none of these manufacturing methods can be used for a connection method in which an anisotropic conductive adhesive is disposed between an electronic component and a circuit board to connect the connecting electrode and the connected electrode that face each other. Met. That is, it is necessary to form a dense region of conductive particles with respect to the binder attached to at least one of the connection electrode or the connected electrode, but a metal mask or the like is adhered to the binder or a core film is interposed. In the above conventional method, the electronic parts and the circuit board are disturbed, and the adhered binder itself may be peeled off together with the metal mask or the like, which is extremely difficult.

  The present invention has been made in view of such conventional problems, and an anisotropic conductive adhesive that can be formed by dispersing dense regions of conductive particles without directly touching an adhesive binder. It aims at providing the manufacturing method of a film.

  In addition, in the connection between the connection electrode and the connected electrode using an anisotropic conductive adhesive, even if the insulation interval between adjacent electrodes is very small, the insulation failure between the electrodes due to the contact between the conductive particles does not occur. An object of the present invention is to provide an electrode connection method that does not occur and that provides connection reliability between electrodes in the pressurizing direction.

In order to achieve the above-described object, a method for producing an anisotropic conductive adhesive film according to claim 1 is provided between an electronic component in which a plurality of connection electrodes are arranged and a circuit board in which a plurality of connected electrodes are arranged. It is a method for producing an anisotropic conductive adhesive film that is disposed and heated and pressed between a connection electrode and a connected electrode, and electrically connected between electrodes in a pressing direction,
The ink containing conductive particles is ejected from the ejection nozzle onto the adhesive resin film by an inkjet method, and the maximum outer diameter of the region is at least between the connection electrodes or the connected electrodes adjacent to each other in the arrangement direction. A dense region of conductive particles smaller than the minimum insulation interval d is formed in a dispersed manner.

  When ink containing conductive particles is ejected onto the adhesive resin film by an ink jet method, the ink is formed on the adhesive resin film as a dense region where the conductive particles are dense. Since the maximum outer diameter of the region is smaller than the minimum insulation distance d between the connection electrodes or the connected electrodes, the electrodes adjacent in the arrangement direction are not electrically connected via the conductive particles.

  In addition, since the dense region of conductive particles is dispersed and formed in the adhesive resin film, any dense region is interposed between the opposing connection electrode and the connected electrode, and the opposing connection electrodes are electrically connected. To do.

  The method for producing an anisotropic conductive adhesive film according to claim 2, wherein a plurality of discharge nozzles are arranged along a longitudinal direction of a nozzle plate disposed on the adhesive resin film, and conductive particles are discharged from each of the plurality of discharge nozzles. The step of discharging the ink containing, and the step of feeding the adhesive resin film in a direction orthogonal to the arrangement direction of the discharge nozzles at a pitch longer than at least the maximum outer diameter A of the dense area, In addition, a dense region of conductive particles is formed in a dispersed manner.

  By causing the ink to protrude from each discharge nozzle, a large number of dense regions are formed in a short time on the adhesive resin film.

  By adjusting the arrangement pitch of the projecting nozzles and the feed pitch of the adhesive resin film, each interval in the orthogonal direction between densely formed regions is set.

  The anisotropic conductive adhesive film manufacturing method according to claim 3 is characterized in that the plurality of discharge nozzles are arranged in parallel in two rows in a staggered manner along the longitudinal direction of the nozzle plate.

  By arranging the discharge nozzles in parallel in two rows, a large number of dense regions are formed in a short time even if the arrangement pitch in the longitudinal direction is increased.

  By arranging the discharge nozzles in a staggered manner in two rows in parallel, even if the interval in the feeding direction of dense regions formed in two rows is shorter than the maximum outer diameter A, they do not overlap each other.

  The method for producing an anisotropic conductive adhesive film according to claim 4 is characterized in that the outline of the projection opening of the discharge nozzle is formed as an ellipse having the longitudinal direction of the nozzle plate as a major axis, and the outline of the dense region of conductive particles is bonded. An ellipse having a major axis in a direction perpendicular to the feeding direction of the resin film is characterized.

  The dense area does not overlap in the feeding direction of the adhesive resin film, and the area of the dense area per unit area of the adhesive resin film is increased.

According to a fifth aspect of the present invention, there is provided an electrode connection method in which an anisotropic conductive adhesive is disposed between an electronic component having a plurality of connection electrodes arranged and a circuit board having a plurality of connection electrodes arranged. An electrode connection method for heating and pressurizing between connecting electrodes and electrically connecting electrodes in a pressurizing direction,
(A) a step of adhering an adhesive resin layer to at least one surface of the connection electrode or the electrode to be connected, and forming an adhesive resin layer; and (b) adhering ink containing conductive particles from a discharge nozzle by an inkjet method. Discharge onto the resin layer, and form a dense region of conductive particles having a maximum outer diameter of the region smaller than the minimum insulating distance d between adjacent connection electrodes or connected electrodes in the arrangement direction in the adhesive resin layer. And (c) heating and pressurizing between the connection electrode and the electrode to be connected, and electrically connecting the electrodes in the pressurizing direction.

  When ink containing conductive particles is ejected onto the adhesive resin layer by an ink jet method, the ink is formed in the adhesive resin layer as a dense region where the conductive particles are concentrated. Since the maximum outer diameter of the region is smaller than the minimum insulation distance d between the connection electrodes or the connected electrodes, the electrodes adjacent in the arrangement direction are not electrically connected via the conductive particles.

  In addition, since the dense regions of conductive particles are dispersed and formed in the adhesive resin layer, any dense region is interposed between the opposed connection electrode and the connected electrode, and electrically connects the opposed connection electrodes. .

  According to the first aspect of the present invention, since a dense region of a plurality of conductive particles is formed on the adhesive resin film by an inkjet method, a simple printing process can be performed without directly contacting the adhesive resin film with adhesiveness. A dense region can be formed.

  Further, since the dense region of the conductive particles can be formed without bringing the adhesive surface of the adhesive resin film into contact with the other, the adhesive resin film can be formed with a thickness as designed without deformation.

  In addition, since the dense region of the conductive particles is formed by ejecting ink by the inkjet method, the size and the formation position of the dense region can be controlled with high accuracy, and using the minimum necessary conductive particles, Insulation between the connection electrodes in the arrangement direction and electrical connection between the connection electrodes in the pressing direction orthogonal to the arrangement direction are possible.

  According to the invention of claim 2, a large number of dense regions can be formed in a short time on the adhesive resin agent film, and by cutting along the feed direction of the adhesive resin agent film having the dense regions formed, Many strip-like anisotropic conductive adhesive films can be produced simultaneously.

  By adjusting the arrangement pitch of the protruding nozzles and the feed pitch of the adhesive resin film, the dense region of conductive particles can be efficiently dispersed and formed in accordance with the size and arrangement pitch of the connection electrodes and the electrodes to be connected.

  According to the invention of claim 3, in contrast to the invention of claim 2, a larger number of dense regions can be formed in a short time.

  Since the dense regions formed on the adhesive resin film are formed in a staggered pattern, even if the interval in the feeding direction is shorter than the maximum outer diameter A, the dense regions can be formed at high density without overlapping each other.

  According to the invention of claim 4, compared to the invention of claim 2 or claim 3, the area of the dense area per unit area of the adhesive resin film is expanded without overlapping the dense use area, The number of conductive particles interposed between the electrode and the connected electrode can be increased.

  According to the invention of claim 5, since the dense region of conductive particles is formed dispersed in the adhesive resin layer, even if the insulating interval in the arrangement direction between the connection electrodes or the connected electrodes is narrowed to a very small interval, the difference is different. Insulation failure due to the isotropic conductive adhesive does not occur.

  In addition, the size and formation position of the conductive particles formed in the adhesive resin layer can be accurately controlled by the ink jet method, so the arrangement direction can be ensured using the minimum necessary conductive particles. The electrical connection between the connection electrodes in the pressurizing direction orthogonal to can be performed.

  Hereinafter, the manufacturing method of the anisotropic conductive adhesive film which concerns on one embodiment of this invention is demonstrated using FIG. 1 thru | or FIG. 1 is a bottom view of the head unit 9, FIG. 2 is a longitudinal sectional view of the head unit 9, FIG. 3 is a plan view showing a state in which the ink 3 is discharged to the adhesive resin film 2, and FIG. FIG. 5 is a plan view of the anisotropic conductive adhesive film 1 excluding the surface separator 7.

  As shown in FIGS. 4 and 5, the anisotropic conductive adhesive film 1 manufactured in the present embodiment has an adhesive layer 4 serving as a binder formed by dispersing dense regions 6 of a large number of conductive particles 5. The dense region 6 of the conductive particles 5 is formed in the adhesive layer 4 by an ink jet method.

  Ink jet system is an ink jet printer that supplies ink to fine discharge nozzles arranged corresponding to the dot rows constituting characters, pressurizes the ink held in the discharge nozzles, and applies ink droplets to the recording paper. In the present invention, it refers to all systems in which ink containing at least conductive particles is ejected from an ejection nozzle onto an adhesive layer in a non-contact manner. In the present embodiment, using the head unit 9 shown in FIGS. 1 and 2, the ink 3 in which conductive particles 5 are blended with an epoxy resin and a solvent is discharged onto the adhesive layer 4. The conductive particles 5 used here are spheres having a nickel layer around a spherical core molded from a resin and further gold-plated on the outer periphery thereof, and an outer diameter of 3 to 4 μm. However, the outer diameter is not necessarily limited to this size. For example, the outer diameter may be 10 μm or more, and the conductive particles may have other external shapes, materials, and structures.

  The head unit 9 is a thermal jet type head unit 9 that heats the ink 3 to generate bubbles, and ejects the ink 3 from the discharge nozzle 10 with the pressure. As shown in FIG. A nozzle plate 12 is laminated on the surface. The nozzle plate 12 is provided with a plurality of discharge nozzles 10 having a circular outline of the discharge ports 10a in parallel along the longitudinal direction (X direction in the figure) of the nozzle plate 12, and the discharge nozzles in each row. 10 are located at positions shifted every half pitch in the X direction, and are arranged in a staggered manner.

  The inside of the discharge nozzle 10 of the nozzle plate 12 is a pressurizing chamber 14 partitioned by a partition wall 13, and driving applied from an unshown drive power supply circuit to the inner surface of the pressurizing chamber 14 facing the discharge nozzle 10. A heating resistor 15 that generates heat by voltage is attached. The pressurizing chamber 14 further communicates with an external ink tank (not shown) via an ink supply groove 16 drilled inward of the unit substrate 11.

  The head unit 9 configured in this manner has a large number of head units 9 that are accommodated in the case 17a of the line head 17 and eject the ink 3 as shown in FIG. The resin agent film 2 is disposed below each discharge nozzle 10. As shown in FIG. 4, the adhesive resin film 2 is obtained by previously attaching an epoxy-based adhesive serving as the binder 4 to the entire front surface side of the back separator 8. In addition to this, an acrylic adhesive may be used as the binder 4 serving as the adhesive layer.

  The line head 17 causes the ink 3 to be simultaneously discharged onto the adhesive resin film 2 from all the two rows of discharge nozzles 10 along the longitudinal direction (X direction in FIG. 3). This is performed by applying a driving voltage to the heating resistor 15 in the pressurizing chamber 14. The pressure chamber 10 is supplied with the ink 3 in which the conductive particles 5 are blended from the ink supply groove 16, and the heat generated by the heating resistor 15 heats the ink 3 in the pressure chamber 10 to generate bubbles. Thus, the pressure is discharged from the discharge nozzle 10 onto the adhesive resin film 2 with that pressure.

  On the adhesive resin film 2, the ink 3 containing the conductive particles 5 adheres, so that as shown in FIG. 4, corresponding to the arrangement sites of the discharge nozzles 10 arranged in two rows in a staggered manner, A dense region 6 of a large number of conductive particles 5 is formed in a staggered manner.

  By making the outline of the discharge port 10a of the discharge nozzle 10 circular, the maximum outer diameter (diameter) A of the dense area 6 having the circular outline is the same as that of the anisotropic conductive adhesive film 1 in which the dense area 6 is formed. It is assumed that it is smaller than the minimum insulation distance d between adjacent connection electrodes (connected electrodes) in the arrangement direction (Y direction in FIG. 7) of the connection electrodes (connected electrodes) 20 and 21 to be connected. Thereby, even if it is the dense region 6 formed by being dispersed at an arbitrary position, it does not straddle both adjacent two connection electrodes, and the conductive particles 5 in the dense region 6 short-circuit between the connection electrodes. Can be prevented.

  Since the maximum outer diameter A of the dense region 6 is determined by the inner diameter of the discharge port 10a of the discharge nozzle 10 formed in the head unit 9 and the distance from the discharge nozzle 10 to the adhesive resin film 2, for example, the discharge nozzle If the outer diameter of the dense region 6 is expanded by 25% by the diffusion of the ink 3 with respect to the inner diameter of 10, the inner diameter of the discharge nozzle 10 is at least larger than the maximum outer diameter of the conductive particles 5, and the minimum between the connection electrodes It is assumed that the insulation distance is less than d * 0.8.

  After the ink 3 is discharged from each of the two discharge nozzles 10, the adhesive resin film 2 is fed by one pitch in the short direction (downward in FIG. 3) of the head unit 9, and again, all the two rows along the X direction The ink 3 is simultaneously discharged from the discharge nozzle 10 onto the adhesive resin film 2 and this is repeated until the dense region 6 is formed on the entire adhesive resin film 2. The feed amount for feeding the adhesive resin film 2 at one pitch is twice the short direction (Y direction) interval Py between the dense regions 6 and 6 formed on the adhesive resin film 2 by the two discharge nozzles 10. As a result, the dense regions 6 with the equal pitch Py are formed in the Y direction in a dispersed manner throughout the adhesive resin film 2.

  As will be described later, the anisotropic conductive adhesive film 1 manufactured in the above-described process has a feeding direction (Y direction in FIG. 3) in the arrangement direction of the connection electrodes (connected electrodes) 20 and 21 (Y in FIG. 7). Direction) and at least one column of the dense region 6 formed at an equal pitch Py in the feed direction overlaps the connecting electrode 20 and the connected electrode 21 (see FIG. 7). It is necessary to set the pitch Py in the feed direction at least as narrow as the width Ey in the arrangement direction of the connection electrodes 20 and the connected electrodes 21 (Y direction in FIG. 7), so that the dense regions 6 do not overlap. It is preferable to make it as small as possible. Therefore, the distance in the short direction (Y direction) of the two rows of discharge nozzles 10 of the head unit 9 that is substantially equal to the feed direction pitch Py of the dense region 6 is also the arrangement direction of the connection electrodes 20 and the connected electrodes 21 (see FIG. 7). A value smaller than the width Ey in the Y direction) is set.

  Moreover, the direction (X direction) orthogonal to the feed direction of the adhesive resin film 2 is the longitudinal direction (X direction in FIG. 7) of the electrodes orthogonal to the arrangement direction of the connection electrodes 20 and the connected electrodes 21. In general, when the connection electrodes (connected electrodes) 20 and 21 are electrically connected using the anisotropic conductive adhesive film 1 described above, the width Ey in the arrangement direction of the connection electrodes (connected electrodes) 20 and 21 is 20 μm. If the width Ex in the longitudinal direction of the electrode is 80 μm, at least five or more conductive particles 5 of 3 to 4 μm are interposed between the connecting electrodes (connected electrodes) 20 and 21 of this size. In this case, it is said that a sufficient connection current for electrical connection can flow.

  From this, assuming that at least one conductive particle 5 is included in the unit dense region 6, five or more dense regions 6 in the width Ex in the longitudinal direction of the electrode are fed to the adhesive resin film 2. The direction pitch Px perpendicular to the feed direction must be present in the direction orthogonal to the direction (X direction), and the width Px of the longitudinal direction (X direction in FIG. 7) of the connection electrodes (connected electrodes) 20 and 21 It is preferable to make it as small as possible as long as it is narrower than 1/5 and does not overlap between the dense regions 6. Accordingly, the distance in the longitudinal direction (X direction) of the discharge nozzles 10 of the head unit 9 that is substantially equal to the pitch Px of the dense region 6 is also the longitudinal direction of the electrodes of the connection electrodes (connected electrodes) 20 and 21 (the X direction in FIG. 7). ) To a value smaller than one fifth of the width Ex.

  As shown in FIG. 4, the adhesive resin film 2 formed by dispersing the dense regions 6 in this way is covered with the surface separator 7, and then the adhesive resin film 2 is 1 mm wide as indicated by the broken line in FIG. 3. Cut along the feeding direction of the adhesive resin film 2 and wound on a winding roller (not shown), the anisotropic conductive adhesive film 1 is manufactured.

  The front separator 7 and the back separator 8 are each formed of a material that can be easily peeled from the adhesive adhesive layer 4. In this embodiment, the thickness of the front separator 7 is 20 μm, and the thickness of the back separator 8 is The thickness of the adhesive conductive film 1 wound around the winding roller is 80 μm, and the thickness of the adhesive layer 4 is 40 μm and the thickness of the adhesive layer 4 is 20 μm.

  In the anisotropic conductive adhesive film 1 manufactured in this way, as shown in FIG. 5, dense regions 6 of a large number of conductive particles 5 are staggered with pitches Px and Py equally spaced in two orthogonal directions. It is formed in a shape.

  Next, a process of electrically connecting the connection electrode 20 and the connected electrode 21 using the anisotropic conductive adhesive film 1 manufactured in this way will be described with reference to FIGS.

  Here, as shown in these drawings, the plurality of connection electrodes 20, 20 of the liquid crystal display element 24 are individually associated with the plurality of connected electrodes 21, 21... Arranged on the printed wiring board 23. The connected electrode 20 connected to the output control terminal of the liquid crystal driver IC is connected in correspondence with the connecting electrode 20 connected to the input / output terminal of the liquid crystal display element 24, and the liquid crystal driver IC Display control of the display element 24 is performed.

  As described above, the width Ey of the connected electrodes 21 in the arrangement direction (Y direction in FIG. 7) is 20 μm, and the insulation distance d between the connected electrodes 21 and 21 adjacent in the arrangement direction is 10 μm. The plurality of connected electrodes 21, 21... Are arranged on the left and right in the drawing at a pitch of 30 μm. Since the connection electrodes 20 connected in correspondence with the connected electrodes 21 are arranged at positions opposite to the connected electrodes 21, the plurality of connecting electrodes 20, 20 are also the same in the same direction as the liquid crystal display element 24. Arranged at pitch.

  The anisotropic conductive adhesive film 1 peels off the surface separator 7 shown in FIG. 5 and exposes the adhesive layer 4 and the dense region 6 with the exposed surface (surface) in the direction in which the connected electrodes 21 and 21 are arranged. Affixed to the electrode 21 to be connected. That is, the feeding direction of the adhesive resin film 2 (Y direction in FIG. 3) is the arrangement direction of the connected electrodes 21 (Y direction in FIG. 7).

  After the adhesive layer 4 is sufficiently adhered to the printed wiring board 23 and the connected electrode 21, the back separator 8 is peeled off as shown in FIGS. 6 and 7. In this state, each connected electrode 21 has at least five dense regions 6 of the conductive particles 5.

  Subsequently, the arrangement surface of the connection electrodes 20, 20 is placed on the adhesive layer 4 so that the plurality of connected electrodes 21, 21. The contact electrode 20 and the connected electrode 21 are pressed while being heated. The pressurizing time is, for example, 5 seconds at 190 ° C. and 15 seconds at 170 ° C.

  By the heating and pressurizing steps, the conductive particles 5 included in the dense region 6 on the connected electrode 21 are sandwiched between the connecting electrode 20 and make the two conductive. At the same time, the thermosetting adhesive layer 4 is cured by heating, and the connecting electrode 20 and the connected electrode 21 are physically fixed while maintaining the above-mentioned pressure state.

  On the other hand, between the electrodes adjacent to each other in the arrangement direction of the connection electrodes (connected electrodes) 20 and 21, there is always a portion where the dense region 6 does not exist, and the conductive particles 5 do not exist. The insulation between the connected electrodes) 20 and 21 is maintained.

  In the above-described embodiment, the dense regions 6 of the conductive particles 5 are dispersed on the adhesive resin film 2 at an equal pitch in a staggered manner, but it is not always necessary to form them at an equal pitch.

According to the above-described embodiment, the dense region 6 of the conductive particles 5 is formed on the adhesive resin film 2 by an ink jet method, so that the adhesive layer 4 to be adhered is not touched during the formation process, Since the discharge direction and discharge speed of the ink 3 containing the conductive particles 5 can be controlled, the dense region 6 of the conductive particles 5 of any size can be formed at any position of the adhesive resin film 2. Can do. Therefore, it is possible to connect the electrodes 20 and 21 by efficiently dispersing the conductive particles 5 using only the minimum necessary conductive particles 5 that can provide connection reliability.
9 to 11 are

  Further, since the dense region 6 of the conductive particles 5 can be formed on the surface without touching the adhesive layer 4 to be adhered using the ink jet method, the electronic component in which the connection electrodes are arranged and the connected electrode are provided. The present invention can also be applied to an electrode connection method in which an anisotropic conductive adhesive is arranged between arranged circuit boards, a connection electrode and a connected electrode are heated and pressurized, and an electrode in a pressing direction is electrically connected.

  Hereinafter, an electrode connection method according to another embodiment of the present invention will be described with reference to FIGS. In these drawings, the same components as those in the above-described embodiment or the components that operate in the same manner are designated by the same reference numerals and the description thereof is omitted.

  Also in the present embodiment, the plurality of connection electrodes 20, 20 of the liquid crystal display element 24 are connected to the plurality of connected electrodes 21, 21,. As shown in FIG. 9, an adhesive serving as a binder is evenly adhered to one of the electrodes, in this case, as shown in FIG. 9, on the plurality of connected electrodes 21, 21. The agent layer 4 is formed.

  Subsequently, the line head 17 is opposed to the adhesive layer 4 formed on the printed wiring board 23 at a predetermined interval, and the ink 3 is applied onto the adhesive layer 4 from the discharge nozzle 10 provided in the line head 17. The step of discharging and the step of relatively moving either the printed wiring board 23 or the line head 17 are alternately repeated, and a large number of dense regions 6 of the conductive particles 5 are formed on the surface of the adhesive layer 4 as shown in FIG. Dispersed to form.

  The maximum outer diameter (diameter) A of the dense region 6 is smaller than the minimum insulation distance d between the adjacent connection electrodes 20 and 20 or the connected electrodes 21 and 21, and is therefore adjacent in the arrangement direction (left and right in the figure). The dense regions 6 do not straddle the electrodes to be insulated, and the electrodes in the arrangement direction are insulated.

  On the other hand, the dense regions 6 of the conductive particles 5 are formed dispersed on the surface of the adhesive layer 4 so as not to overlap each other, and a plurality of dense regions 6 exist on the vertical lines of the connection electrodes 20.

  Subsequently, the arrangement surface of the connection electrodes 20, 20 is placed on the adhesive layer 4 so that the plurality of connected electrodes 21, 21. The adhesive layer 4 which is thermosetting is cured, and the printed wiring board 23 and the liquid crystal display element 24 are physically fixed.

  At the same time, as shown in FIG. 12, when the connection electrode 20 and the connected electrode 21 are pressurized, the conductive particles 5 contained in the dense region 6 interposed between the two electrodes 20 and 21 are separated from both the electrodes 20. , 21 is contacted with a high contact pressure, and the adhesive layer 4 is cured, so that the contact state is maintained, and the electrodes 20 and 21 in the pressurizing direction are electrically connected.

  In the above-described embodiment, the thermal jet type head unit 9 has been described as an ink jet type, but a piezo jet type that ejects ink by deformation of a piezoresistive element (piezoelectric element) may be used, and the flow path is changed. Thus, a continuous method in which ink is ejected to a predetermined position of the adhesive resin film 2 may be used.

  Further, the line head 17 employed in the ink jet type line printer simultaneously ejected the ink 3 from the plurality of ejection nozzles 10 in one row, but the smaller number of ejection nozzles 10 moved relative to the adhesive resin film 2. The dense region 6 of the conductive particles 5 may be dispersed and formed.

  Further, although the contour of the discharge port 10a of the discharge nozzle 10 is circular and the contour of the dense region 6 is circular, the contour of the dense region 6 changes the shape of the discharge port 10a, or the adhesive resin film 2 or adhesive layer. 4 and any of the ejection nozzles 10 can be formed in an arbitrary shape by relatively moving during ejection of the ink 3. For example, in the first embodiment, when the outline of the discharge port 10a is formed as an ellipse whose major axis is the longitudinal direction of the nozzle plate 12, a dense region of the conductive particles 5 formed on the adhesive resin film 2 is used. The outline 6 becomes an ellipse having a major axis in the direction (X direction) orthogonal to the feeding direction of the adhesive resin film 2. Therefore, when the anisotropic conductive adhesive film 1 is attached to the electrode 21 whose longitudinal direction is the X direction shown in FIG. 7, the dense region 6 has a width that does not extend between the electrodes 21, 21 and the X direction is long. The outline of the ellipse is used as an axis, the area of the dense region 6 per unit length in the arrangement direction (X direction) of the electrodes 21 can be increased, and the number of conductive particles 5 arranged on each electrode 21 is increased. Thus, the electrodes 20 and 21 in the pressurizing direction can be more reliably electrically connected.

  The present invention is particularly suitable for manufacturing an anisotropic conductive adhesive film for connecting electrodes that cannot be connected by solder at a narrow pitch, and for connecting electrodes using an anisotropic conductive adhesive.

4 is a bottom view of the head unit 9. FIG. FIG. 3 is a partially omitted vertical sectional view of the head unit 9. 3 is a plan view showing a state in which ink 3 is ejected onto an adhesive resin film 2. FIG. FIG. 4 is an enlarged vertical cross-sectional view of a main part of FIG. 3. It is a top view of the anisotropic conductive adhesive film 1 except the surface separator 7. FIG. 4 is a longitudinal sectional view showing a state in which the back separator 8 is peeled off and the adhesive layer 4 is brought into close contact with the connected electrode 21 of the printed wiring board 23. FIG. FIG. 7 is a plan view of FIG. 6. FIG. 3 is a longitudinal sectional view showing a state in which a connection electrode 20 and a connected electrode 21 are connected. 3 is a longitudinal sectional view showing a state in which an adhesive layer 4 is attached to a connected electrode 21 of a printed wiring board 23. FIG. It is a longitudinal cross-sectional view which shows the state which formed the dense area | region 6 of the electroconductive particle 5 in the surface of the adhesive bond layer 4 of FIG. FIG. 3 is a longitudinal sectional view showing a state in which a connection electrode 20 and a connected electrode 21 are connected.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anisotropic conductive adhesive film 2 Adhesive resin film 3 Ink 5 Conductive particle 6 Dense area
10 Discharge nozzle 20 Connection electrode 21 Connected electrode 23 Circuit board (printed wiring board)
24 Electronic components (liquid crystal display elements)

Claims (5)

Arranged between an electronic component in which a plurality of connection electrodes are arranged and a circuit board in which a plurality of connection electrodes are arranged, between the connection electrodes and the connection electrodes are heated and pressurized, and the electrodes in the pressurizing direction are electrically connected. A method for manufacturing an anisotropic conductive adhesive film to be connected,
By ink jet method, ink containing conductive particles is discharged from the discharge nozzle onto the adhesive resin film,
The adhesive resin film is formed by dispersing dense regions of conductive particles having a maximum outer diameter A of the region that is at least smaller than the minimum insulation distance d between connection electrodes or connected electrodes in the arrangement direction. A method for producing an anisotropic conductive adhesive film. A plurality of discharge nozzles are arranged along the longitudinal direction of the nozzle plate disposed on the adhesive resin film,
A step of discharging ink containing conductive particles from each of the plurality of discharge nozzles, and a step of feeding the adhesive resin agent film at a pitch longer than at least the maximum outer diameter A of the dense region in a direction orthogonal to the arrangement direction of the discharge nozzles. , Repeat alternately,
The method for producing an anisotropic conductive adhesive film according to claim 1, wherein a dense region of conductive particles is dispersed and formed on the adhesive resin film. The method for producing an anisotropic conductive adhesive film according to claim 2, wherein the plurality of discharge nozzles are arranged in parallel in two rows in a staggered manner along the longitudinal direction of the nozzle plate. The outline of the discharge nozzle projection opening is formed as an ellipse with the longitudinal direction of the nozzle plate as the major axis, and the outline of the dense region of the conductive particles is defined as the major axis in the direction perpendicular to the feeding direction of the adhesive resin film. The method for producing an anisotropic conductive adhesive film according to any one of claims 2 and 3, wherein the ellipse is an ellipse. An anisotropic conductive adhesive is disposed between an electronic component in which a plurality of connection electrodes are arranged and a circuit board in which a plurality of connection electrodes are arranged, and the pressure between the connection electrodes and the connection electrodes is heated and pressurized. An electrode connection method for electrically connecting the electrodes of
(A) attaching the adhesive layer to at least one of the connection electrode or the connection electrode;
(B) An ink containing conductive particles is ejected from an ejection nozzle onto an adhesive resin layer by an inkjet method, and a connection electrode or a connected electrode whose maximum outer diameter A is adjacent to the adhesive resin layer at least in the arrangement direction A step of dispersing and forming a dense region of conductive particles smaller than the minimum insulation interval d between
(C) heating and pressurizing between the connection electrode and the connected electrode, and electrically connecting the electrodes in the pressurizing direction;
An electrode connection method comprising:

Images