JP2006156785A - Connecting structure of ic chip and external wiring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To electrically conduct a chip electrode and an external-electrode terminal surely by interposing a sufficient number of conductive particles between the chip electrode for an IC chip and the external-electrode terminal for an external wiring. <P>SOLUTION: When an output terminal 12a and an input terminal 12b for the IC chip 11 for driving a liquid crystal are connected to a panel-electrode terminal 6 for a liquid-crystal display panel 1, a weir 17 for the conductive particles for damming up the flowing conductive particles 14 is projected and formed to the panel electrode-terminal 6 side at one end on the downstream side in the flowing direction of the conductive particles 14, on one surface opposed to the panel-electrode terminal 6 at the output terminal 12a and the input terminal 12b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a connection structure between an IC chip and an external wiring, and in particular, an adhesive material containing a plurality of conductive particles for a chip electrode of an IC chip and an external electrode terminal of an external wiring in a display panel, a flexible wiring board or the like. In particular, the present invention relates to a connection structure between an IC chip and an external wiring that are suitable for connection.

  Conventionally, a display panel that displays information such as specific figures and characters by selectively applying an electric field to a predetermined portion of a pair of substrates is widely used as a display panel for various electric devices such as mobile phones and computers. Has been.

  The panel electrode terminal of the display panel is electrically connected to the chip electrode of the driving IC chip for driving the display panel. For example, the liquid crystal driving IC chip is mounted on the liquid crystal display panel. The liquid crystal display panel is connected directly by being mounted directly or by being mounted on a flexible wiring board or the like.

  FIG. 5 is a schematic cross-sectional view showing an example of a connection structure between a conventional liquid crystal driving IC chip and a liquid crystal display panel.

  As shown in FIG. 5, the liquid crystal display panel 21 is provided with a panel electrode 23 on the inner surfaces of a pair of substrates 22 facing each other, and one substrate 22 is larger in plan view than the other substrate 22. It has the terminal part 24 formed. A panel electrode 23 extends from the terminal portion 24 to serve as a first panel electrode terminal 25a. One end of the terminal portion 24 is independent of the panel electrode 23 and the first panel electrode terminal 25a. The 2nd panel electrode terminal 25b formed in this way is provided.

  The base 26a of the liquid crystal driving IC chip 26 has an output terminal 32a, which is a plurality of chip electrodes corresponding to the first panel electrode terminal 25a, and an input, which is a plurality of chip electrodes corresponding to the second panel electrode terminal 25b. A terminal 32b is provided.

  In order to mount the liquid crystal driving IC chip 26 on the liquid crystal display panel 21, first, an adhesive 29 containing a plurality of conductive particles 28 in the portion of the terminal portion 24 where the panel electrode terminals 25 a and 25 b are formed. Apply. Subsequently, the output terminal 32a of the liquid crystal driving IC chip 26 is opposed to the first panel electrode terminal 25a through the adhesive 29, and the input terminal 32b of the liquid crystal driving IC chip 26 is opposed to the second panel electrode terminal 25b. After the liquid crystal driving IC chip 26 is placed on the terminal portion 24, pressure is applied to the liquid crystal driving IC chip 26. Then, by electrically connecting the panel electrode terminals 25a and 25b of the liquid crystal display panel 21 to the output terminals 32a and 32b of the liquid crystal driving IC chip 26 through the conductive particles 28 of the adhesive 29, The liquid crystal driving IC chip 26 is mounted on the liquid crystal display panel 21.

  However, when the liquid crystal driving IC chip 26 is mounted on the liquid crystal display panel 21 as described above, when the liquid crystal driving IC chip 26 is pressed via the adhesive 29, as shown in FIG. The contained conductive particles 28 flow to the outer edge side of the liquid crystal driving IC chip 26. As a result, there is a possibility that a sufficient quantity of conductive particles 28 does not remain between the panel electrode terminals 25a and 25b and the input terminal 32b and the output terminal 32a, and the conduction cannot be achieved. Had a problem.

  Further, with the recent narrowing of the frame of the liquid crystal display panel 21 and the fine pitch of the panel electrode terminals 25a and 25b, the connection area between the panel electrode terminals 25a and 25b and the output terminals 32a and the input terminals 32b is also reduced. A sufficient number of conductive particles 28 cannot remain between the panel electrode terminals 25a and 25b and the output terminal 32a and the input terminal 32b. It was more difficult to achieve continuity.

  On the other hand, by increasing the density of the conductive particles 28 in the adhesive 29, the number of conductive particles 28 interposed between the panel electrode terminals 25a and 25b and the output terminals 32a and 32b may be increased. . However, in such a case, a large number of conductive particles 28 are located between the panel electrode terminals 25a and 25b, between the output terminals 32a and between the input terminals 32b. As a result, short-circuiting occurs between adjacent chip electrodes. It had a problem that there is a risk of being.

  The present invention has been made in view of these points, and by inserting a sufficient number of conductive particles between the chip electrode of the IC chip and the external electrode terminal of the external wiring to achieve conduction, the chip It is an object of the present invention to provide a connection structure between an IC chip and an external wiring that can reliably conduct an electrode and an external electrode terminal.

  In order to achieve the above object, the feature of the connection structure between the IC chip and the external wiring according to the first aspect of the invention is that the chip electrode of the IC chip for driving the display panel corresponds to the chip electrode. In the connection structure of the IC chip and the external wiring, in which the external electrode terminal of the formed external wiring is connected via an adhesive containing conductive particles, the chip electrode and the external electrode terminal are connected. In this case, the conductive particle weir for damming the flowing conductive particles is a surface facing the external electrode terminal of the chip electrode, and the downstream electrode in the flow direction of the conductive particles, the external electrode The point is that it protrudes toward the terminal side.

  Here, the external wiring includes various wirings that are electrically connected to the IC chip, such as a display panel such as a liquid crystal display panel and wiring of a flexible wiring board.

  According to the first aspect of the present invention, when the tip electrode is connected to the external electrode terminal, the flow of the conductive particles is blocked by the conductive particle dam, and the conductive particles of the conductive particle dam are dammed. A plurality of conductive particles can be retained on the edge, that is, the panel electrode terminal.

  In addition, the connection structure between the IC chip and the external wiring according to the second aspect of the invention is characterized in that the conductive particle weir is formed at one end portion of the chip electrode perpendicular to the longitudinal direction of the external electrode terminal. There is in point.

  According to the second aspect of the invention, by forming the conductive particle weir at one end portion orthogonal to the longitudinal direction of the external electrode terminal, the connection area between the chip electrode and the external electrode terminal is ensured as wide as possible. And more conductive particles can be interposed between the chip electrode and the external electrode terminal.

  According to a third aspect of the present invention, the connecting structure between the IC chip and the external wiring is characterized in that the protruding height of the conductive particle weir is 1/4 to 1/2 of the diameter of the conductive particle. It is in the point formed by the dimension.

  According to the third aspect of the present invention, the protrusion height of the conductive particle weir 17 is formed to be ½ to ¼ of the diameter of the conductive particle, thereby adding to the IC chip. Even when the conductive particles are somewhat crushed by the pressure, the conduction between the chip electrode and the external electrode terminal can be reliably ensured.

  Furthermore, the connection structure between the IC chip and the external wiring according to the invention described in claim 4 is characterized in that the inner edge for blocking the conductive particles of the conductive particle weir is on the downstream side in the flow direction of the conductive particles. It is in the point that is curved.

  According to the fourth aspect of the present invention, the conductive particles blocked by the conductive particle weir can be reliably retained at the inner edge of each conductive particle weir formed by bending. The conductive particles can be interposed between the chip electrode and the external electrode terminal.

  As described above, according to the connection structure between the IC chip and the external wiring according to the present invention, the chip electrode and the external electrode terminal are connected to each other with a plurality of conductive particles interposed between the chip electrode and the external electrode terminal. As a result, the chip electrode and the external electrode terminal can be reliably conducted.

  Hereinafter, an embodiment of a connection structure between an IC chip and external wiring according to the present invention will be described with reference to FIGS. In this embodiment, a description will be given using a connection between a liquid crystal driving IC chip for driving a liquid crystal display panel as an IC chip and a liquid crystal display panel wiring as an external wiring.

  FIG. 1 is a schematic plan view showing a connection structure between a liquid crystal driving IC chip and a liquid crystal display panel according to this embodiment, and FIG. 2 is a schematic cross-sectional view taken along line AA of the connection structure of FIG. is there.

  As shown in FIGS. 1 and 2, the liquid crystal display panel 1 has a pair of transparent substrates 2, and the first transparent substrate 2 a out of the two transparent substrates 2 has a planar shape as compared with the second transparent substrate 2 b. It has the terminal part 3 formed large.

  A plurality of panel electrodes 5 made of ITO (Indium Tin Oxide) or the like are provided on the inner surfaces of the transparent substrates 2 facing each other, and each panel electrode 5 extends to the terminal portion 3. Thus, the first panel electrode terminal 6a is formed.

  In addition, a plurality of second panel electrode terminals 6 b that are independent from the panel electrodes 5 and the first panel electrode terminals 6 a are provided at one end of the terminal portion 3.

  Both transparent substrates 2 are integrally joined by a sealing material 8 applied to the outer peripheral edge of the inner surface, and inside the both transparent substrates 2 and the sealing material 8 are a liquid crystal 9 and a spacer (not shown). Is enclosed.

  On the other hand, in the IC chip 11 for driving the liquid crystal, as shown in FIG. 3, circuit wiring 11b is formed on one surface of the base 11a having a rectangular planar shape, and the first panel electrode terminal is formed on one surface of the base 11a. A passivation film 11c is formed at a predetermined portion excluding the position corresponding to 6a and the second panel electrode terminal 6b so as to cover the end of the circuit wiring 11b. A predetermined position on the circuit wiring 11b including the end covered with the passivation film 11c corresponds to the output terminal 12a as a plurality of chip electrodes corresponding to the first panel electrode terminal 6a and the second panel electrode terminal 6b. Input terminals 12b as a plurality of chip electrodes are provided. Since the output terminal 12a and the input terminal 12b are formed across the edge of the passivation film 11c, the center part of the top surface on the protruding side is formed in a recessed shape.

  The liquid crystal driving IC chip 11 has an output terminal 12a facing the first panel electrode terminal 6a and an input terminal 12b facing the second panel electrode terminal 6b. And is mounted via an adhesive 15 containing a plurality of conductive particles 14.

  The output terminals 12a and the input terminals 12b of the liquid crystal driving IC chip 11 have respective conductive particles that flow toward the outer edge of the liquid crystal driving IC chip 11 when the output terminals 12a and the input terminals 12b are connected to the panel electrode terminals 6. A conductive particle weir 17 is provided for blocking 14.

  As shown in FIG. 4, each of the conductive particle weirs 17 is a downstream edge in the flow direction of the conductive particles 14 of the output terminal 12a and the input terminal 12b, and extends in the longitudinal direction of the panel electrode terminals 6a and 6b. It is formed at one end orthogonal to protrude toward the panel electrode terminal 6 side. The projecting height dimension of each conductive particle weir 17 is shorter than the diameter dimension of the conductive particles 14, and is preferably ¼ to ½ of the diameter dimension of the conductive particles 14, and the conductive particles 14 having a diameter of 4 μm are formed. When using the contained adhesive material 15, the conductive particle weir 17 may be formed to have a protruding height of 1 to 2 μm.

  Further, the inner edge 17 a of each conductive particle weir 17 is formed to be curved downstream in the flow direction of the conductive particles 14.

  The conductive particle weir 17 is formed by pressing the output terminal 12a and the input terminal 12b against a mold having a predetermined level difference.

  The method for forming the conductive particle weir 17 is not limited to the present embodiment. For example, the thickness of the passivation film 11c in the portion corresponding to the position where the conductive particle weir 17 is formed is larger than that in the other portions. It can also be formed by forming the output terminal 12a and the input terminal 12b from the thick passivation film 11c.

  Next, the operation of this embodiment will be described.

  First, the adhesive 15 containing the conductive particles 14 is applied to the arrangement position of the liquid crystal driving IC chip 11 in each panel electrode terminal 6 of the terminal portion 3.

  Subsequently, liquid crystal driving is performed on the terminal portion 3 while aligning the output terminal 12a and the first panel electrode terminal 6a and aligning the input terminal 12b and the second panel electrode terminal 6b via the adhesive material 15. A pressure is applied on the liquid crystal driving IC chip 11 with the IC chip 11 mounted thereon.

  Then, pressure is applied to the liquid crystal driving IC chip 11, whereby each conductive particle 14 flows to the outer edge side of the liquid crystal driving IC chip 11. At this time, the conductive particles 14 located on the panel electrode terminal 6 are blocked by the conductive particle weirs 17 of the output terminal 12 a and the input terminal 12 b and stay at the inner edge 17 a of the conductive particle weir 17. .

  Then, while the conductive particles 14 are crushed by the output terminals 12a and the input terminals 12b, the adhesive 15 is solidified in the state where the conductive particles 14 are interposed in the side edges 17a of the conductive particle weirs 17, thereby driving the liquid crystal The output terminal 12 a and the input terminal 12 b of the IC chip 11 and the panel electrode terminals 6 of the liquid crystal display panel 1 are electrically connected through the conductive particles 14. Thus, the liquid crystal driving IC chip 11 is mounted on the liquid crystal display panel 1.

  According to the present embodiment, when the liquid crystal driving IC chip 11 is mounted on the liquid crystal display panel 1, the flow of the conductive particles 14 is blocked by the conductive particle dams 17, and the inner edge 17 a of the conductive particle dams 17. That is, a plurality of conductive particles 14 can be retained on the panel electrode terminal 6.

  Therefore, the output terminal 12a, the input terminal 12b, and the panel electrode terminal 6 can be connected with the plurality of conductive particles 14 interposed between the output terminal 12a, the input terminal 12b, and the panel electrode terminal 6. Thus, the output terminal 12a, the input terminal 12b, and the panel electrode terminal 6 can be reliably conducted.

  As a result, conventionally, the conductive particles 14 having a quantity equivalent to 50% of the connection area between the output terminal 12a and the input terminal 12b and the panel electrode terminal 6 can be interposed, but according to this embodiment. For example, the conductive particles 14 having a quantity corresponding to an area of 60 to 70% could be interposed.

  Further, the protruding height dimension of the conductive particle weir 17 is formed to be ½ to ¼ of the diameter dimension of the conductive particle 14, so that the conductive particle is applied by pressurization to the liquid crystal driving IC chip 11. Even if 14 is somewhat crushed, it is possible to reliably ensure conduction between the output terminal 12 a and the input terminal 12 b and the panel electrode terminal 6.

  Further, since the inner edge 17a of each conductive particle weir 17 is curved and formed downstream in the flow direction of the conductive particles 14, the conductive particles 14 blocked by the respective conductive particle weirs 17 are surely secured. Can be retained at the inner edge 17a of each conductive particle weir 17, and more conductive particles 14 can be interposed between the panel electrode terminal 6 and the output terminal 12a.

  Furthermore, since the conductive particle weir 17 is formed at one end portion of the chip electrode perpendicular to the longitudinal direction of the panel electrode terminal 6, the connection area between the output terminal 12a and the input terminal 12b and the panel electrode terminal 6 is as much as possible. It can be ensured widely, and more conductive particles 14 can be interposed between the output terminal 12 a and the input terminal 12 b and the panel electrode terminal 6.

  In addition, this invention is not limited to the said embodiment, A various change is possible as needed.

  For example, in the present embodiment, the panel electrode terminal 6 of the liquid crystal display panel 1 is used as the external wiring. However, the present invention is not limited to this, and further, when an IC chip is mounted on a flexible wiring board. You may use for the connection structure of this IC chip and the wiring of a flexible wiring board.

  Further, the shape of the conductive particle weir 17 is not limited to this embodiment. For example, the inner edge 17a of each conductive particle weir 17 may be formed in a straight line. Further, in this embodiment, the conductive particle weir 17 is formed at one end edge of the chip electrode. For example, in the conductive electrode weir 17 of the chip electrode located at the corner of the rectangular substrate 11a, the conductive particle 14 may be formed at the downstream edge in the flow direction, that is, at the two edges on the outer edge side of the liquid crystal driving IC chip 11 so that the planar shape is L-shaped.

Schematic plan view showing an embodiment of a connection structure between an IC chip and external wiring according to the present invention 1 is a schematic cross-sectional view taken along line AA in FIG. Schematic cross-sectional view enlarging the chip electrode of FIG. Schematic plan view showing the main part of FIG. Typical sectional drawing which shows an example of the connection structure of the conventional IC chip and external wiring Schematic plan view showing the main part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 2a 1st transparent substrate 2b 2nd transparent substrate 3 Terminal part 5 Panel electrode 6a 1st panel electrode terminal 6b 2nd panel electrode terminal 11 Liquid crystal drive IC chip 12a Output terminal 12b Input terminal 14 Conductive particle 15 Adhesive material 17 Weir for conductive particles 17a Inner edge

Claims (4)

An IC chip in which a chip electrode of an IC chip for driving a display panel and an external electrode terminal of an external wiring formed corresponding to the chip electrode are connected via an adhesive containing conductive particles In the connection structure between and external wiring
When connecting the chip electrode and the external electrode terminal, a conductive particle weir for blocking the flowing conductive particles is a surface facing the external electrode terminal in the chip electrode, and the conductive particles A connection structure between an IC chip and external wiring, characterized in that it is formed at the downstream edge in the flow direction so as to protrude toward the external electrode terminal.   The connection structure between the IC chip and the external wiring according to claim 1, wherein the conductive particle weir is formed at one end of the chip electrode perpendicular to the longitudinal direction of the external electrode terminal.   The connection structure between the IC chip and the external wiring according to claim 1 or 2, wherein the protruding height of the conductive particle weir is formed by a size of 1/4 to 1/2 of the diameter of the conductive particle. . 4. The IC chip according to claim 1, wherein an inner edge of the conductive particle weir for blocking the conductive particles is formed to be curved downstream in the flow direction of the conductive particles. 5. Connection structure with external wiring.

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