KR100356142B1 - Structure and method of connecting the aluminum wiring - Google Patents

Abstract

This invention prevents corrosion of the aluminum wiring in a connection part in the structure which connects an aluminum wiring and a to-be-connected body with an anisotropic conductive material.

The anode substrate 3 of the envelope 2 of the fluorescent display tube 1 protrudes from the box shape. Wiring such as an electrode in the envelope 2 is drawn out to the surface of one end 3a of the positive electrode substrate 3 to form the external terminal portion 5 of the aluminum foil. The flexible cable 8 is connected to the edge part of the external terminal part 5 by thermocompression bonding via the anisotropic conductive material 9 (ACF). There is a portion without the ACF 9 between the tip portion 8b of the flexible cable 8 and the external terminal portion 5. That is, the ACF 9 does not protrude out from between the flexible cable 8 and the external terminal portion 5. The connection part is covered with the mold material 12. Since there is no part from which the anisotropic conductive material 9 containing chlorine ions which corrode aluminum protrudes, the outer terminal part 5 of aluminum does not corrode.

Description

STRUCTURE AND METHOD OF CONNECTING THE ALUMINUM WIRING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring connection structure particularly useful when connecting flexible connection wiring or the like to an aluminum wiring formed on a substrate with an anisotropic conductive material, and a manufacturing method thereof.

FIG. 3 shows an example of a connection structure in which the external terminal portion 101 of the fluorescent display tube 100 and the flexible cable 102 which is external wiring are connected through an anisotropic conductive material 103 (ACF). have.

In general, the fluorescent display tube 100 is a box-shaped envelope (envelope) formed by airtightly assembling a plate member made of an insulating material such as glass with a sealing adhesive material. And an insulating material such as glass, and means (structure) for hermetically storing an anode as a light emitting display portion, a cathode as an electron source, a control electrode for controlling electrons, and the like. An anode as a light emitting display portion having a phosphor layer, a cathode as an electron source, a control electrode for controlling electrons, and the like are housed therein. On the inner surface of the anode substrate 104 that forms part of the envelope, a wiring conductor of an internal electrode is wound around the anode. The wiring conductor hermetically penetrates the sealing portion of the envelope and is drawn out to the surface of the anode substrate 104 outside the envelope to form the external terminal portion 101. Usually, many of these external terminal parts 101 are provided in a minute pitch on the anode substrate outside the envelope, and since the width thereof is quite small, the resistance is often high. For this reason, in order to use a high resistance electrically-conductive material, such as IT0 (Induium Tin Oxide), there exist some difficulties, and generally an aluminum thin film is used. The wiring in the enclosure and a part of the external terminals outside the enclosure are covered with a cross 105.

In the case where the fluorescent display tube 100 is connected to a drive circuit (not shown) or the like provided outside, a flexible cable 102 as shown in FIG. 3 may be used. This flexible cable 102 is collectively referred to as TAB, and the Cu wiring 107 is formed on one side of the polyimide film 106 serving as the base material. The pitch of the Cu wiring 107 corresponding to the pitch of the external terminal portion 101 of the fluorescent display tube 100 to be connected is selected.

The anisotropic conductive material 103 (ACF) connecting the external terminal portion 101 of the fluorescent display tube 100 and the wiring 107 of the flexible cable 102 has conductive particles in a thermosetting adhesive such as epoxy. Is dispersed, and is usually supplied as a sheet-like conductive material. The anisotropic conductive material 103 is mounted on the external terminal portion 101 of the fluorescent display tube 100, and the wiring 107 of the flexible cable 102 is positioned thereon, and these are thermally compressed.

The anisotropic electrically conductive material 103 can obtain high electroconductivity in the thickness direction by melt | dissolving an adhesive agent by heating and pressurization, and being caught between the electrodes which the electrically conductive particle disperse | distributes. In the plane direction, the conductive particles are dispersed to such an extent that they do not come into contact with each other and the adhesive becomes an insulator, so that high insulation can be obtained. Mechanical connection between the conductive particles and the electrode is obtained by an adhesive. For this reason, the plurality of external terminal portions 101 of the fluorescent display tube 100 conduct only with the respective wirings 107 of the flexible cables 102 positioned with respect to them, so that the external terminal portions 101 and the flexible cables are electrically connected. 102 is certainly connected mechanically.

The connecting portion of the external terminal portion 101 and the flexible cable 102 is covered with a mold member 108 such as resin for the purpose of waterproofing or the like.

In the conventional connection structure described above, the anisotropic conductive material 103 is included when the external terminal portion 101 and the flexible cable 102 of the fluorescent display tube 100 are thermally compressed with the anisotropic conductive material 103 interposed therebetween. Since the epoxy resin to be fluid has fluidity, the anisotropic conductive material 103 protrudes from both, and protrudes to the external terminal 101 which does not face the flexible cable 102. And the problem that the part 110 of the outer terminal part 101 made from aluminum which the projecting anisotropic conductive material 103 contacted corrodes generate | occur | produces.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching the cause of this corrosion, the present inventors acquired the following knowledge. First, the epoxy resin which is an adhesive agent of the anisotropic conductive material 103 contains hydrolyzable chlorine. In the portion sandwiched between the outer terminal portion 101 and the flexible cable 102, since the epoxy resin is cured by thermocompression bonding, chlorine cannot be taken in and moved in the mesh structure of the cured product, so that the aluminum of the outer terminal 101 Less chance to react. However, since the hardening reaction by thermocompression bonding is incomplete as the protruded anisotropic conductive material 103, chlorine ion approaches aluminum of the outer terminal part 101, and destroys the oxide film of aluminum. Then, the electrochemical effect is caused by the effect of the potential difference between the external terminal portion 101 and the wiring of the flexible cable 102 when the fluorescent display tube 100 is driven and the effect of moisture contained in the mold material over a long time. Reaction occurs and corrosion of aluminum in the external terminal portion 101 proceeds.

MEANS TO SOLVE THE PROBLEM This invention was made | formed based on the inventor's knowledge about this in order to solve the problem of aluminum wiring corrosion mentioned above, In the connection structure which connects an aluminum wiring and a to-be-connected body with an anisotropic conductive material, The purpose is to prevent corrosion of aluminum wiring.

1 is a cross-sectional view showing an example of an embodiment of the present invention;

2 is a cross-sectional view showing a connection step in an example of an embodiment of the present invention;

3 is a cross-sectional view showing an example of a connection structure between a conventional fluorescent display tube and an external cable.

Explanation of symbols for the main parts of the drawings

DESCRIPTION OF SYMBOLS 1: Fluorescent display tube 3: Anode substrate as a board | substrate

4: wiring conductor

5: external terminal portion as aluminum wiring

5a: End portion of external terminal portion 8: Flexible cable as a to-be-connected body

8a: end of flexible cable 8b: tip of flexible cable

9: anisotropic conductive material 20: thermal crimping device

The connection structure of the aluminum wiring of Claim 1 is anisotropic to the aluminum wiring (external terminal part 5) formed on the board | substrate (anode board | substrate 3), and the to-be-connected body (flexible cable 8) outside the said board | substrate. In the connection structure of the aluminum wiring connected using the electrically conductive material 9, the said anisotropic electrically conductive material does not protrude from the said aluminum wiring and the to-be-connected body, It is characterized by the above-mentioned.

The connection structure of the aluminum wiring of Claim 2 is the aluminum wiring (external terminal part 5) formed on the board | substrate (anode substrate 3) of the fluorescent display tube 1, and the connection wiring outside the said fluorescent display tube (flexibility) In the connection structure of the aluminum wiring which connects the cable 8 using the anisotropic conductive material 9, the said anisotropic conductive material does not protrude from the said aluminum wiring and the said connection wiring top.

The connection structure of the aluminum wiring of Claim 3 is the connection structure of the aluminum wiring of Claim 1 or 2 WHEREIN: The said anisotropic electrically-conductive material 9 is an epoxy type adhesive agent containing many micro conductive particles, It is characterized by the above-mentioned. .

The connection method of the aluminum wiring of Claim 4 is connected to the aluminum wiring which connects aluminum wiring (external terminal part 5) to the to-be-connected body (flexible cable 8) using the anisotropic conductive material 9. First, an anisotropic conductive material 9 is mounted on an end portion 5a of an aluminum wiring (outer terminal portion 5) extending in a predetermined direction, and then a connected body (flexible) that extends in a direction opposite to the predetermined direction. The end part 8a of the to-be-connected body (flexible cable 8) is raised so that the front end part 8b of the end part 8a of the sex cable 8 faces the aluminum wiring (external terminal part 5). It is superimposed on the anisotropic conductive material 9, the overlapping area | region of predetermined length A of an aluminum wiring (external terminal part 5) and a to-be-connected body (flexible cable 8) is provided, and the said anisotropic conductive material The blood corresponding to the overlapping region such that 9 does not protrude from the overlapping region; The anisotropic conductive material 9 is cured by pressing while heating the upper surface of the connecting body (flexible cable).

According to the structure of Claims 1-3 and the structure obtained by the method of Claim 4, an anisotropic electrically conductive material from between aluminum wiring (external terminal part 5) and external to-be-connected body (flexible cable 8). Since 9 is not protruding, the aluminum wiring does not corrode.

The above and other objects, features, aspects, advantages, and the like of the present invention will become more apparent from the following detailed embodiments described with reference to the accompanying drawings.

Embodiment of the Invention

An example of an embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, the connection structure of this example is demonstrated with reference to FIG.

As shown in Fig. 1, the fluorescent display tube 1 is provided with a box-like envelope 2 formed by hermetically assembling a plate made of an insulating material such as glass with a sealing material. As for the positive electrode board | substrate 3 which comprises a part of envelope 2, the one end part 3a protrudes from the box-shaped outline of envelope 2. Inside the envelope 2, an anode formed by depositing a phosphor layer on an anode conductor, a cathode serving as an electron source, a control electrode for controlling electrons, and the like are housed. The wiring conductor 4 made of the aluminum film connected to these electrodes passes through the sealing portion of the envelope 2 airtightly to the surface of one end 3a of the anode substrate 3 outside the envelope 2. It draws out and comprises the external terminal part 5 which consists of aluminum films. The external terminal portion 5 is formed by arranging the number of electrodes in the envelope 2 and the number corresponding to the structure at a predetermined pitch. These wiring conductors 4 and the external terminal part 5 are manufactured by the same process.

The wiring conductor 4 in the envelope 2 is covered with a cross layer 6 as an insulating layer made of lead oxide-based glass, for example lead borosilicate glass. In order to prevent reflection, such as external light, the insulating layer which comprises the cross layer 6 may contain the pigment.

The flexible cable 8 as a to-be-connected body is connected to the edge part of the external terminal part 5 by thermocompression bonding via the anisotropic electrically conductive material 9 (ACF). In the flexible cable 8 (TAB), a plurality of Cu wirings 11 are formed on a surface of one sheet of polyimide film 10 as a substrate at a predetermined pitch. The pitch of the Cu wiring 11 corresponding to the pitch of the external terminal part 5 of the fluorescent display tube 1 to be connected is selected. The anisotropic electrically conductive material 9 is a sheet-like material which disperse | distributed electroconductive particle to thermosetting adhesives, such as an epoxy system. Although not shown in the drawing, the other end of the cable 8 is connected to a connection portion such as a printed circuit board on which a drive circuit or a drive circuit is mounted.

The anisotropic conductive material 9 shown in FIG. 1 has each end part 5a (and adjacent outer terminal parts 5 and 5) of the plurality of outer terminal parts 5 arranged at predetermined intervals in a direction perpendicular to the ground. (Area between) overlap. From above, the flexible cable 8 which makes the left side the edge part 8a in the figure overlaps. Here, the tip portion 8b of the end 8a of the flexible cable 8 is not in contact with the anisotropic conductive material 9 and is an area between the external terminal portion 5 (and the adjacent external terminal portions 5, 5). Face to face). That is, the edge part 5a of the external terminal part 5 and the edge part 8a of the flexible cable 8 form the overlap area. In the overlapping region, the length in the longitudinal direction of the wiring in the transverse direction in FIG. 1 is A, and the length in the direction perpendicular to this corresponds to the entire width of the plurality of external terminal portions 5. Within this overlapping region, an anisotropic conductive material 9 is formed between the tip 8b of the end 8a of the flexible cable 8 and the outer terminal portion 5 (and between adjacent outer terminal portions 5, 5). There is no part. In other words, the anisotropic conductive material 9 does not protrude from the flexible cable 8 and the external terminal portion 5 (and between adjacent external terminal portions 5, 5). That is, the anisotropic conductive material 9 does not protrude from the flexible cable 8 and the external terminal part 5 with respect to the longitudinal direction of the wiring in the horizontal direction in FIG. As described above, in this example, the anisotropic conductive material 9 does not protrude from the overlapping region.

The anisotropic electrically conductive material 9 is in the state hardened | cured by the thermocompression bonding process, and the flexible cable 8 and the external terminal part 5 are electrically and mechanically reliably connected. And the connection part of the flexible cable 8 and the external terminal part 5 is covered with the mold material 12 in this example, and it makes the waterproof performance more reliable.

As a specific numerical example, while the mounting length of the flexible cable 8, ie, the length A of the overlapping region A = 2.5 to 3.0 mm, the length B of the anisotropic conductive material 9 is 1.5 to 2 mm is an appropriate value. Moreover, the thickness of an aluminum wiring is about 1 micrometer (sputter vapor deposition), and the copper wiring of TAB is about 18 micrometers (0.4 micrometer tin plating).

According to the structure of this example, at least as long as the use of the fluorescent display tube is common, the aluminum film of the external terminal portion 5 does not corrode as easily as conventionally. And, as in the present example, when the connecting portion of the external terminal portion 5 and the cable 8 is covered with a mold material such as resin, high moisture resistance can be obtained even in a special environment with high humidity, so that corrosion of the aluminum film is further generated. Difficult to do

In the present invention, the fluorescent display tube is not only a display element for emitting a segment of a fixed pattern, but also a fluorescent display tube or an optical writing element capable of selectively driving a display portion of a fine matrix pattern to perform desired character display or graphic display. Also includes a fluorescent light emitting tube. Usually, in the latter fluorescent light emitting tube, the anode, which is the light emitting portion, is divided into fine patterns, and the number of wiring conductors wound therefrom is large, and therefore, the number of external terminals drawn out is large. For example, as a fluorescent light emitting tube of A4 size (emission width 210 mm) and 300 dpi, the pitch of the wires drawn out on both sides of the total dot number of about 2500 and the outer envelope becomes about 0.17 mm, and the conventional fixed pattern display Compared to the wiring of fluorescent display tubes, it is very dense and compact.

The wires drawn on both sides of the envelope are connected to the TAB as described above, but the external shape of the TAB can be reduced by making the wiring pitch smaller and higher density. The smaller the TAB, the smaller the size of the polyimide film 10 serving as the base material can be used, and the number of TABs increases.

In the above situation, for example, the wiring pitch of the external terminal portion of the fluorescent light emitting tube to which the structure of the present example is applied is 110 μm, for example. As described above, since corrosion of the wiring occurs electrochemically, the life time of corrosion decreases as the electric field strength increases. When wiring pitch becomes small, since the electric field strength between wirings becomes strong, wiring corrosion becomes more likely to occur.

Therefore, when the research and development of the fluorescent light emitting tube proceeds in the direction of high resolution, the wiring pitch of the external terminal portion becomes smaller, and thus the problem of corrosion becomes more serious, and therefore the structure of the corrosion protection according to this example is very important. do.

Next, the connection process of the external terminal part 5 and the cable 8 in this example is demonstrated with reference to FIG.

In FIG. 2, reference numeral 20 denotes a thermocompression bonding apparatus used for thermocompression bonding by the anisotropic conductive material 9 described above. The thermocompression bonding apparatus 20 is provided with the air cylinder 21 as a pressurizing means, and the heater head 22 as a heating means provided in the front-end | tip of the rod of the air cylinder 21. As shown in FIG.

On the end part 5a of the external terminal part 5, the anisotropic electrically conductive material 9 is mounted.

The end portion 8a of the flexible cable 8 is superimposed on the anisotropic conductive material 9 so that the tip portion 8b of the end portion 8a of the flexible cable 8 faces the external terminal portion 5. In order to prevent the anisotropic conductive material 9 from protruding from the overlapping region, the upper surface of the flexible cable 8 corresponding to the overlapping region is pressed while heating with the thermocompression bonding apparatus 20.

The binder of the anisotropic conductive material 9 is softened and has fluidity. Conventionally, the anisotropic conductive material fluidized at this time protrudes from the outer diameter of the TAB, but in this example, the anisotropic conductive material 9 has a suitable length between the front end 8b of the flexible cable 8 and the external terminal portion 5. (Particularly, the TAB dimension and the heater head dimension are enlarged to reduce the ACF dimension. For example, the TAB dimension is 2.5 mm to 2.8 to 3.0 mm, the ACF dimension is 2.0 mm to 1.5 mm, and the head is provided. 2.5-3.0 mm in dimensions), including this portion, the entire overlapped region of the flexible cable 8 and the external terminal portion 5 was thermocompressed. Therefore, the thermocompression bonding apparatus 20 with larger heater head 22 was used than before. Thereby, the fluidized anisotropic conductive material 9 could be hardened without protruding between the flexible cable 8 and the external terminal portion 5. The Cu wiring 11 of the flexible cable 8 and the external terminal part 5 (Al) are electrically and mechanically connected by the anisotropic electrically conductive material 9 hardened | cured.

At this time, the conductive particles (for example, metal balls having a diameter of about 5 μm) in the anisotropic conductive material 9 are crushed between the Cu wiring 11 of the cable 8 and the external terminal portion 5 (Al). This is conducting. For example, if the electrically-conductive particle is a metal ball with a diameter of about 5 micrometers, it fills about 2 micrometers in thickness, and is electrically conductive.

By the above-described steps, the plurality of external terminal portions 5 of the fluorescent display tube 1 conduct only with the respective wirings 11 of the flexible cables 8 positioned with respect to them, and the external terminal portions 5 The flexible cable 8 is certainly connected mechanically.

Then, the connection part of the external terminal part 5 and the flexible cable 8 is coat | covered with mold material 12, such as resin, for waterproofing.

As explained above, according to the connection structure and the connection method of this example, since the anisotropic electrically conductive material 9 was comprised so that it might not protrude from the connection part of the aluminum external terminal part 5 and the external cable 8, the anisotropy which protruded The problem that aluminum of the external terminal part 5 corrodes because of the electrically conductive material 9 has been solved.

According to the present invention, since the anisotropic conductive material does not protrude from the connecting portion between the aluminum wiring and the connected object, aluminum corrosion of the connecting portion can be eliminated.

Moreover, in the fluorescent display tube which often takes the structure which connects many external terminal parts which consist of aluminum thin films to an external cable with an anisotropic conductive material, even if it operates in high temperature, high humidity environment, it does not cause wiring corrosion. In particular, the present invention is particularly useful in that high connection reliability can be maintained. Further, the present invention further ensures waterproof performance because the connection portion between the connected object and the aluminum wiring is covered with a mold material. . In addition, high moisture resistance can be obtained even in a special environment with high humidity, so that corrosion of the aluminum film is more difficult to occur.

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

Claims (4)

In the connection structure of the aluminum wiring which formed on the board | substrate, and the to-be-connected body outside the said board | substrate using an anisotropic conductive material, The aluminum wiring and the connected body are connected by thermal compression of the anisotropic conductive material, In the connection part of the said aluminum wiring and the to-be-connected body, at least the periphery of the aluminum wiring exposed on the said board | substrate is coat | covered with a mold material, The said anisotropic electrically conductive material does not protrude between the said board | substrate and the said to-be-connected body, The aluminum wiring connection structure characterized by the above-mentioned. In the connection structure of the aluminum wiring formed on the board | substrate of a fluorescent display tube, and the aluminum wiring which connects the connection wiring outside the said fluorescent display tube using an anisotropic conductive material, The aluminum wiring and the connection wiring are connected by thermal compression of the anisotropic conductive material, In the connecting portion of the aluminum wiring and the connecting wiring, at least the periphery of the aluminum wiring exposed on the substrate is covered with a mold material, The said anisotropic electrically conductive material does not protrude between the said board | substrate and the said connection wiring, The connection structure of the aluminum wiring characterized by the above-mentioned. The method according to claim 1 or 2, The connection structure of the aluminum wiring whose said anisotropic electrically-conductive material is an epoxy adhesive containing many micro conductive particles. In the connecting method of the aluminum wiring which connects aluminum wiring with a to-be-connected body using an anisotropic conductive material, Mounting an anisotropic conductive material on the end of the aluminum wiring extending in a predetermined direction, The end of the to-be-connected body is superimposed on the anisotropic conductive material so that the tip end of the end of the to-be-connected body extending in the direction opposite to the predetermined direction faces the aluminum wiring, and the aluminum wire and the predetermined length of the to-be-connected object overlap. To create an area, In order to prevent the anisotropic conductive material from protruding from the overlapping region, the upper surface of the to-be-connected body corresponding to the overlapping region is pressed while heating to cure the anisotropic conductive material, The connection part of the said aluminum wiring and the to-be-connected body WHEREIN: The connection method of the aluminum wiring characterized by covering at least the periphery of the aluminum wiring exposed on the said board | substrate with a mold material.