JP3006985B2 - Display substrate and its mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display substrate and a mounting structure thereof. More specifically, liquid crystal display devices, EL
(Electroluminescence) The present invention relates to a display substrate constituting a part of a display panel such as a display device, and a mounting structure thereof.

[0002]

2. Description of the Related Art FIG. 5 shows a matrix type liquid crystal display device mounted by a conventional general mounting method (driving IC mounting method). The liquid crystal display panel 201 is configured by sealing liquid crystal (not shown) between a lower substrate 221 and an upper substrate 222 as display substrates. Lower substrate 22
1 is provided with a large number of wirings 206 and 207 extending from the display area 203 where the pixels are formed toward the peripheral edge, and the ends of the wirings 206 and 207 on the peripheral side of the substrate serve as electrode terminals. (Note that, for the sake of simplicity, throughout this specification, electrode terminals are included in wiring.) As shown in FIG. 6, for example, the lower substrate 221
Wiring 206 is a Ta film 209 having a thickness of about 3000
It has a two-layer structure of an ITO (tin-added indium oxide) film 210 having a thickness of about 800 ° provided thereon (for example, JP-A-63-195687). FIG.
As shown in the figure, the wiring 2 of the lower substrate 221 is in the mounted state.
06 and 207 are connected to flexible wiring boards 204 and 205 on which driving ICs 224 and 225 are mounted, respectively. Specifically, as shown in FIG. 6, for example, the flexible wiring board 204 is provided with a base material surface 217 made of a polyimide resin.
And an output terminal 208 made of a Cu material plated with Sn, Au, or the like. An end of the wiring 206 of the lower substrate 221 and the output terminal 208 of the flexible wiring board 206 are connected via a conductive connection member 211.
During operation, the display signal output by the driving IC 224 is:
Output terminal 208 of flexible wiring board 204, connection material 2
11, is supplied to the display area via the wiring 206 of the lower substrate 221.

FIG. 3 shows a matrix type liquid crystal display device mounted by a COG (chip-on-glass) method. The liquid crystal display panel 101 is configured by sealing liquid crystal (not shown) between a lower substrate 121 and an upper substrate 122 as display substrates. Lower substrate 12
1, a large number of wirings extending from the display region 123 where the pixels are formed toward the peripheral edge are provided, and the ends of the wirings 126a and 126b are electrode terminals. Wirings 126b and 127b extending toward the periphery of the substrate are provided further away from the wirings 126a and 127a on the peripheral side of the substrate than the wirings 126a and 127a. As shown in FIG. 4, for example, the lower substrate 121
The wiring 126a and the wiring 126b have a thickness of 300
A Ta film 129 having a thickness of about 0 ° and a thickness 8 provided thereon.
It has a two-layer structure with an ITO film 130 of about 00 °. As shown in FIG. 3, in the mounted state, the lower substrate 121
The driving ICs 124 and 125 are mounted between the wirings 126a and 127a and the wirings 126b and 127b, respectively, and the flexible wiring boards 133 and 134 are connected to the wirings 126b and 127b. More specifically, as shown in FIG. 4, for example, the driving IC 124 has an output-side bump electrode 128a and an input-side bump electrode 128b. These output-side bump electrode 128a and input-side bump electrode 1
28b are connected to the peripheral end of the wiring 126a of the lower substrate 121 and the display area side end of the wiring 126b via the conductive connecting members 131 and 131, respectively.
Further, for example, the flexible wiring board 133 has an output terminal 135 made of a Cu material plated with Sn, Au, or the like on a base material surface 137 made of a polyimide resin. The output terminal 135 is connected to the peripheral end of the wiring 126b of the lower substrate 121 via the connection member 136 having conductivity. During operation, a power supply and an input signal are input to the driving IC 124 via the output terminal 135 of the flexible wiring board 133, the connecting member 136, the wiring 126b, the connecting member 131, and the input-side bump electrode 128b. Then, the display signal output by the driving IC 124 is supplied to the display area via the output-side bump electrode 128a, the connecting material 131, and the wiring 126a.

In any of the above liquid crystal display devices, the wirings 206 and 207 (FIGS. 5 and 6) of the display substrate, the wiring 126a,
126b, 127a, and 127b (FIGS. 3 and 4) have a two-layer structure of a Ta film and an ITO film.
The presence of the TO film can prevent the surface of the Ta film from being oxidized after the completion of the substrate. Since the sheet resistance of the Ta film is about 3 Ω / □ and the sheet resistance of the ITO film is about 50 Ω / □, the supply of power and signals from the peripheral side of the substrate to the display region is mainly performed in the lower Ta layer. Is done through the membrane.

[0005]

However, the wirings 206 and 207 (FIGS. 5 and 6) and the wirings 126a, 126b, 127a and 127b of the display substrate as in the prior art.
When FIGS. 3 and 4 have a two-layer structure of a Ta film and an ITO film, the surface of the lower Ta film is oxidized when the ITO film is formed. In the process of patterning the ITO film,
When performing a reworking operation, the Ta film is affected by the etchant (ferric chloride solution) for the ITO film and is deteriorated. For this reason, there is a problem that the interface resistance between the ITO film and the Ta film varies greatly, and the yield decreases. According to experiments, the interfacial resistance between the ITO film and the Ta film is about 2 due to such a variation factor during the substrate manufacturing process.
It has been found that it varies in the range of × 10 ⁴ to 10 ⁷ Ω · μm ² . Thus, the surface of the Ta film is oxidized and deteriorated,
When the interface resistance with the ITO film is increased, the resistance from the driving IC to the display area is increased, and the display signal is distorted. As a result, the display state is deteriorated. This effect is caused by the increase in the definition of the display, the wirings 206 and 207 (FIGS. 5 and 6) and the wirings 126a, 126b, 127a and 12a.
When the area of 7b (FIGS. 3 and 4) is reduced, it becomes serious. For example, in the case of the COG mounting method shown in FIG. 4, the area of the wiring 126a is much smaller than that of a general mounting method (driving IC mounting method). For this reason, the increase in resistance is large, and the effect on the display state is also large. The area of the wiring 126b is equal to the area of the wiring 126a.
However, the increase in resistance in the line to which power is to be supplied is fatal even if the increase is small, and significantly degrades the operating state of the driving IC.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display substrate which can be manufactured at a high yield without being affected by process variations and can obtain good display quality, and a mounting structure thereof.

[0007]

In order to achieve the above object, a display substrate according to claim 1 is a display substrate for forming a part of a flat panel display device, wherein
In a display substrate having a wiring for transmitting a signal from a peripheral portion of the substrate surface to an internal display area, the wiring pattern is provided on a tantalum film provided in contact with the substrate surface and on the tantalum film. And a titanium film is provided between the tantalum film and the tin-added indium oxide film in at least a part of the wiring pattern. It is characterized by.

According to a second aspect of the present invention, there is provided a mounting structure for a display substrate, comprising the display substrate according to the first aspect, wherein a driving signal for generating the signal is provided in a portion of the wiring existing in the peripheral portion. An output terminal of a flexible wiring board on which an IC is mounted is connected.

According to a third aspect of the present invention, there is provided a display substrate mounting structure including the display substrate according to the first aspect, wherein the wiring has a pattern extending from the display area to the peripheral portion, A first wiring having a region provided with a film, and a second wiring having a pattern extending toward the periphery of the substrate on a peripheral side of the substrate with respect to the first wiring and having a region provided with the titanium film. The output side electrode of the driving IC for generating the signal is connected to the end of the first wiring on the substrate peripheral side, and the end of the second wiring is connected to the display area side. An input electrode of a driving IC is connected, and an output terminal of a flexible wiring board for supplying an input signal to the driving IC is connected to an end of the second wiring on the peripheral side of the substrate. And

According to a fourth aspect of the present invention, in the mounting structure of the display substrate according to the third aspect, the tin-added indium oxide film of the first wiring and the driving IC are provided. The output-side electrode, the tin-added indium oxide film of the second wiring, and the input-side electrode of the driving IC are connected via an anisotropic conductive film.

According to a fifth aspect of the present invention, in the display substrate according to the first aspect, the wiring has a pattern extending from the display area to the peripheral portion, and the titanium film is provided. And a second wiring having a pattern extending toward the periphery of the substrate on the peripheral side of the substrate with respect to the first wiring and having a region where the titanium film is provided, at least A molybdenum film is provided on the tin-doped indium oxide film at the end of the first wiring on the substrate peripheral side and at the end of the second wiring on the display region side. .

Further, a mounting structure for a display substrate according to claim 6 includes the display substrate according to claim 5, wherein
The output electrode of the drive IC for generating the signal is connected to the molybdenum film at the end of the wiring on the substrate peripheral side, while the molybdenum film at the display area side end of the second wiring is connected to the molybdenum film. The input side electrode of the driving IC is connected to the driving IC, and the driving I
An output terminal of a flexible wiring board for supplying an input signal to C is connected.

According to a seventh aspect of the present invention, in the mounting structure of a display substrate according to the sixth aspect, the molybdenum film is provided at an end of the first wiring on a peripheral side of the substrate. An output electrode of the driving IC;
That the molybdenum film at the end of the wiring on the display region side and the input electrode of the driving IC are connected via a paste material containing silver or an alloy of silver and palladium as conductive particles. Features.

[0014]

According to the display substrate of the first aspect, when a Ti (titanium) film is formed on a Ta (tantalum) film to form a wiring, unlike the case where an ITO (tin-added indium oxide) film is directly formed, There is no oxidation of the Ta film surface. Further, when the ITO film is formed on the Ti film, the degree of oxidation of the surface of the Ti film is much lighter than the case where the surface of the Ta film is oxidized. Further, the Ti film is not affected by the etchant (ferric chloride solution) for the ITO film. Therefore, the interfacial resistance between the Ta film and the Ti film and the interfacial resistance between the Ti film and the ITO film are less affected by process fluctuations than in the prior art, and are low and stable. Therefore, this display substrate can be manufactured with a high yield, and good display quality can be obtained after mounting.
In addition, it is possible to cope with higher definition display in the future. Further, while the insulating film is provided on the ITO film in the region where the Ti film is provided, the insulating film is removed in the region of the two-layer film where the Ti film is not provided.
The three-layer film composed of a film, a Ti film, and an ITO film is protected by the insulating film, and the region from which the insulating film is removed is used as an electrode terminal, and the electrode terminal is used as an output terminal of a flexible wiring board or a driving IC. Electrodes can be connected. If the insulating film on the three-layer film is also removed, the Ti film is attacked through the ITO film when the insulating film is etched.

In the display substrate mounting structure according to a second aspect, at least a part of the wiring pattern of the display substrate includes:
Since the titanium film is provided between the Ta film and the ITO film, the interface resistance between the Ta film and the Ti film and the interface resistance between the Ti film and the ITO film are reduced, so that the flexible wiring board is reduced. The resistance (including the resistance at the end) of the wiring from the output terminal to the display area is lower and more stable than before. Therefore, good display quality can be obtained.

According to the third aspect of the present invention, since the Ti film is provided in at least a part of each of the first and second wiring patterns of the display substrate, the output terminal of the flexible wiring board is provided. From the first wiring to the input electrode of the driving IC (including the resistance at the end),
And the resistance (including the resistance at the end) of the second wiring from the output side electrode of the driving IC to the display area.
However, it is in a low and stable state as compared with the related art. Therefore,
Good display quality can be obtained.

According to a fourth aspect of the present invention, the ITO film of the first wiring and the output side electrode of the driving IC, and the ITO film of the second wiring and the driving film are connected to each other.
Since the input electrode of C is connected via the anisotropic conductive film, the lower surface of the driving IC (chip) is protected by the anisotropic conductive film. Therefore, a separate driving IC
High reliability can be obtained without applying a sealing resin.

In the display substrate according to the present invention, the ITO film is removed at least at the end of the first wiring on the substrate peripheral side and at the end of the second wiring on the display area side, and the tantalum is removed. Since the molybdenum film is provided on the film, the connection resistance between the output electrode and the input electrode (generally made of Au) of the driving IC is further reduced. Claim 1
As with the display substrate of the above, while being manufactured with high yield,
Good display quality can be obtained after mounting. In addition, it is possible to cope with higher definition of the display in the future.

In the mounting structure of a display substrate according to the present invention, the molybdenum film forms an end of the first wiring on the substrate peripheral side, an end of the second wiring on the display area side, and an output side of the driving IC. The connection resistance between the electrode and the input side electrode is further reduced.
Therefore, the resistance (including the resistance at the end) of the first wiring from the output terminal of the flexible wiring board to the input side electrode of the driving IC, and the resistance from the output side electrode of the driving IC to the display area. The resistance (including the resistance at the end) of the second wiring up to the above is further reduced. Therefore, good display quality can be obtained, and connection reliability can be improved.

According to a seventh aspect of the present invention, there is provided a display substrate mounting structure, wherein the first wiring has a peripheral portion on the substrate side and the second wiring has a paste material containing silver or an alloy of silver and palladium as conductive particles. The connection resistance between the display area side end and the output side electrode and the input side electrode of the driving IC is further reduced.
Therefore, the resistance (including the resistance at the end) of the first wiring from the output terminal of the flexible wiring board to the input side electrode of the driving IC, and the resistance from the output side electrode of the driving IC to the display area. The resistance (including the resistance at the end) of the second wiring up to the above is further reduced. Therefore, good display quality can be obtained, and connection reliability can be improved.

[0021]

FIG. 1 is a sectional view of a main part of a liquid crystal display device according to a first embodiment of the present invention. This liquid crystal display device is COG
The liquid crystal display panel 1, the driving IC 24, and the flexible wiring board 33 are provided.

The liquid crystal display panel 1 is configured such that liquid crystal is sealed between a lower substrate 21 as a display substrate and an upper substrate (not shown). The lower substrate 21 is provided with a large number of first wirings 46a extending from the display area (left side in the figure) where the pixels are formed toward the peripheral edge, and the ends of each of the wirings 46a are connected to the electrodes. Terminal. A second wiring 46b extending toward the periphery of the substrate is provided further away from the first wiring 46a on the peripheral side of the substrate than the first wiring 46a. These wirings 46
The patterns a and b are composed of a Ta film 29 having a thickness of about 3000 ° provided in contact with the lower substrate 21 and a Ta film 29 having a thickness of about 3000 °.
It is formed of a two-layer film composed of an ITO film 30 having a thickness of about 800 ° provided thereon. Then, a Ti film 40 having a thickness of about 3000 ° is provided between the Ta film 29 and the ITO film 30 in at least a part of the wiring pattern. In this example, the Ti film 40 includes the wirings 46a,
6b is provided in a region excluding the end (electrode terminal).
The sheet resistance of the Ta film is about 3Ω / □, the sheet resistance of the ITO film is about 50Ω / □, and the sheet resistance of the Ti film is about 3Ω / □.
The insulating film 42 covers substantially the entire area of the lower substrate 21 except for the ends (electrode terminals) of the wirings 46a and 46b.

In the process of manufacturing the display substrate 21,
When the Ti film 40 is formed on the Ta film 29, unlike the case where the ITO (tin-added indium oxide) film 30 is directly formed,
The surface of the Ta film 29 is not oxidized. Further, when the ITO film 30 is formed on the Ti film 40, the degree of oxidation of the surface of the Ti film 40 is much lighter than the case where the surface of the Ta film 29 is oxidized. Further, the Ti film 40 is not affected by the etchant (ferric chloride solution) for the ITO film 30. Therefore, the Ta film 29 and Ti
The interfacial resistance between the film 40 and the Ti film 40 and ITO
The interface resistance with the film 30 is less susceptible to process fluctuations than in the prior art, and is low and stable. Therefore, the display substrate 1 can be manufactured with a high yield. In addition, it is possible to cope with higher definition of the display in the future. The reason why the Ti40 film is not provided at the ends of the wirings 46a and 46b is that when the insulating film 42 is etched,
This is because Ti40 is attacked through the ITO film.

The driving IC 24 includes an output-side bump electrode 28
a, input-side bump electrode 28b. These bump electrodes 28a and 28b are formed by gold plating. The flexible wiring board 33 has an output terminal 35 made of a Cu material plated with Sn or Au on a base material surface 37 made of a polyimide resin.

In the illustrated mounting state, the driving IC 24 is mounted between the wirings 46a and 46b of the lower substrate 21, and the flexible wiring board 33 is connected to the wiring 46b. That is, the output side bump electrode 2 of the driving IC 24
8a, the input-side bump electrode 28b is connected to the substrate peripheral end (electrode terminal) of the wiring 46a of the lower substrate 21 and the display area side end of the wiring 46b via the anisotropic conductive film 41, respectively. I have. In addition, the output terminal 35 of the flexible wiring board 33 is connected to the peripheral end of the wiring 46 b of the lower substrate 21 via the anisotropic conductive film 36. In addition,
The connection of the anisotropic conductive films 41 and 36 is performed by heating and pressing.

In operation, a power supply and an input signal are applied to the output terminal 35, the connecting member 36, and the wiring 46 of the flexible wiring board 33.
b, the connection material 41, and the input side bump electrode 28b, and are supplied to the driving IC 24. Then, the display signal output from the driving IC 24 is supplied to the display area via the output-side bump electrode 28a, the connecting material 41, and the wiring 46a.

Since the Ti film 40 is provided in at least a part of each pattern of the wirings 46a and 46b, the Ti film 40 extends from the output terminal 35 of the flexible wiring board 33 to the input side electrode 28b of the driving IC 24. Wiring 46a
(Including the resistance at the end) and the resistance (including the resistance at the end) of the wiring 46b from the output electrode 28a of the driving IC 24 to the display area are lower than those in the related art. It is in a stable state. Therefore, good display quality can be obtained. Since the lower substrate 21 and the driving IC 24 are connected via the anisotropic conductive film 41, the driving IC
The lower surface of (chip) 24 is protected. Therefore, high reliability can be obtained without separately applying a resin for sealing the driving IC 24.

According to an experiment using a special pattern for measurement, the wirings 46a and 46b of the display substrate 21 described above have a gap between the Ta film 29 and the Ti film 40 even when there is a process variation. Interface resistance is 5 × 10 ² to 8 × 10 ² Ω · μm ²
And the interface resistance between the Ti film 40 and the ITO film 30 becomes 5
× 10 ^{2 to} 2 × 10 ³ Ω · μm ² . Therefore, the resistance from the Ta film 29 to the ITO film 30 via the Ti film 40 can be estimated to be 10 ^{3 to} 2.8 × 10 ³ Ω · μm ^{2 in} which both are added. Therefore, it was able to be reduced much as compared with 2 × 10 ⁴ to 10 ⁷ Ω · μm ² when the Ti film 40 was not provided (conventional). In addition, the variation due to the process variation was significantly reduced.

Actually, the resistance (including the resistance at the end) of the wiring 46b is ^{3 to} 4Ω when the area of the Ti film 40 is about 10 ⁴ μm ² , and 5 to 29Ω when the Ti film is not provided.
The value and variation of the resistance were significantly reduced as compared with the case of FIG.

FIG. 2 is a sectional view showing a main part of a liquid crystal display device according to a second embodiment of the present invention. This liquid crystal display device is mounted by the COG method as in the first embodiment, and includes a liquid crystal display panel 1 ′, a driving IC 24, and a flexible wiring board 33. For the sake of simplicity, the same components are denoted by the same reference numerals. Since the driving IC 24 and the flexible wiring board 33 are the same as those of the first embodiment, the description is omitted.

The liquid crystal display panel 1 'is constructed by sealing liquid crystal between a lower substrate 21 as a display substrate and an upper substrate (not shown). The lower substrate 21 is provided with a large number of first wirings 66a extending from the display area (left side in the drawing) where the pixels are formed toward the peripheral edge, and the ends of each of these wirings 66a are connected to the electrodes. Terminal. Further on the substrate peripheral side of the first wiring 66a, there is provided a second wiring 66b extending toward the substrate periphery in a state of being separated from the first wiring 66a. These wirings 66
The patterns a and 66b are composed of a Ta film 29 provided in contact with the lower substrate 21 and an ITO film provided on the Ta film 29.
It is formed of a two-layer film including the film 30. Then, the Ta film 2 is formed in at least a part of the region of the wiring pattern.
A titanium film 40 is provided between the substrate 9 and the ITO film 30. The Mo film 60 is provided at the end of the first wiring 66a on the substrate peripheral side and at the end of the second wiring 66b on the display area side. The sheet resistance of the Mo film is about 0.5Ω /
□. The insulating film 42 is formed on the wiring 66 of the lower substrate 21.
a, 66b covers almost the entire area except the end portions.

In the step of fabricating the lower substrate 21, the interface resistance between the Ta film 29 and the Ti film 40 and the resistance between the Ti film 40 and the ITO film 30 are the same as in the first embodiment. Is less susceptible to process variations than in the past, and is low and stable. Therefore, the display substrate 1 'can be manufactured with a high yield. Also,
It will be possible to cope with higher definition display in the future. It is to be noted that the Mo film 60 is provided only on the end of the first wiring 66a on the substrate peripheral side and the end of the second wiring 66b on the display area side because the Mo film is weak to moisture and the insulating film This is because water is eroded through the gap formed in the step 42.

In the illustrated mounting state, the driving IC 24 is mounted between the wirings 66a and 66b of the lower substrate 21, and the flexible wiring board 33 is connected to the wiring 66b. That is, the output side bump electrode 2 of the driving IC 24
8a, the input side bump electrode 28b is made of Ag as conductive particles.
Ag / Pd paste 61,6 containing an alloy consisting of Pd and Pd
1, the wiring 66a of the lower substrate 21 is connected to the peripheral end (electrode terminal) of the wiring 66a and the wiring 66b to the display area side end. Further, the output terminal 35 of the flexible wiring board 33 is connected to the lower substrate 2 via the anisotropic conductive film 36.
One of the wirings 66b is connected to the peripheral end of the substrate. A gap between the drive IC 24 and the lower substrate 21 is filled with a sealing resin 62. The connection using the Ag / Pd paste material 61 is performed by supplying an appropriate amount of the Ag / Pd paste material 61 to the output-side bump electrode 28a and the input bump electrode 28b of the driving IC 24 by a transfer method, positioning, and then heating. This is performed by curing the Ag / Pd paste material 61. The connection of the anisotropic conductive film 36 is performed by heating and pressing.

In operation, a power supply and an input signal are supplied to the output terminal 35, the connecting member 36, and the wiring 46 of the flexible wiring board 33.
b, the connection material 41, and the input side bump electrode 28b, and are supplied to the driving IC 24. Then, the display signal output from the driving IC 24 is supplied to the display area via the output-side bump electrode 28a, the connecting material 41, and the wiring 46a.

Here, as in the first embodiment, the wiring 66
a, 66b at least in part of the area of each pattern.
Since the film 40 is provided, the flexible wiring board 33
From the output terminal 35 to the input-side electrode 28b of the driving IC 24
, And the resistance (including the resistance at the end) of the wiring 66b from the output electrode 28a of the driving IC 24 to the display area, including the resistance at the end. It is in a low and stable state as compared with the conventional case. Therefore, good display quality can be obtained.
Further, the Mo film 60 and the Ag / Pd paste 61 allow the wiring 66a to have an edge on the substrate peripheral side, the wiring 66b to have a display area side, and the output electrode 28 of the driving IC 24.
a, The connection resistance with the input side electrode 28b can be further reduced. Therefore, the output terminals 3 of the flexible wiring board 33
5 and the resistance (including the resistance at the end) of the wiring 66a from the driving IC 24 to the input electrode 28b and the resistance of the wiring 66b from the output electrode 28a of the driving IC 24 to the display area ( (Including resistance at the ends). Therefore, better display quality can be obtained, and the reliability of the connection can be improved.

Actually, the resistance of the wiring 66b (including the resistance at the end) is about 4 × 10 ⁴ μm ² of the area of the Ti film 40.
In this case, the resistance was 1.5 to 2.5 Ω, and the resistance value and the variation were significantly reduced as compared with 2 to 10 Ω when the Ti film was not provided.

In this embodiment, the Ti film and the Mo film newly provided in the wiring or on the wiring are films which are usually used for forming a display area of a liquid crystal display panel.
It is not specially formed for carrying out the present invention.
Therefore, the implementation of the present invention does not increase the cost.

Further, in this embodiment, the Ti film 40 is formed only in a part of the wiring pattern due to the limitation of the process surface. However, when there is no limitation of the process surface, the Ti film 40 is formed over the entire area of the wiring pattern. Preferably, 40 is formed.

In this embodiment, the liquid crystal display device mounted by the COG method has been described. However, the scope of the present invention is not limited to this. The present invention can also be applied to a general mounting type (driving IC mounting type) liquid crystal display device. Also in this case, the wiring resistance from the output terminal of the flexible wiring board to the display area can be made lower and stable as compared with the related art, and good display quality can be obtained. Further, the present invention can be widely applied to other types of flat display devices such as an EL display device.

[0040]

As is apparent from the above description, in the display substrate according to the first aspect, when a Ti (titanium) film is formed on a Ta (tantalum) film for forming a wiring, ITO (tin-added indium oxide) is directly used. Unlike the case of forming a film, the surface of the Ta film is not oxidized. In addition, ITO is applied on the Ti film.
When the film is formed, the degree of oxidation of the surface of the Ti film depends on Ta.
It is much lighter than when the film surface is oxidized.
In addition, the Ti film is an etchant for the ITO film (second chloride).
Iron solution). Therefore, T
interface resistance between a film and Ti film, and Ti film and ITO
The interface resistance between the film and the film is less susceptible to process fluctuations as compared with the prior art, and can be stabilized at a low level. Therefore, it can be manufactured at a high yield, and a good display quality can be obtained after mounting. In addition, it is possible to cope with higher definition display in the future. Also, while an insulating film is provided on the ITO film in the region where the Ti film is provided,
Since the insulating film is removed in the region of the two-layer film where the i film is not provided, the three-layer film including the Ta film, the Ti film, and the ITO film is protected by the insulating film. At the same time, an output terminal of a flexible wiring board or an electrode of a driving IC can be connected to the electrode terminal using the region from which the insulating film has been removed.

In the display substrate mounting structure according to the second aspect, at least a part of the wiring pattern of the display substrate has
Since the titanium film is provided between the Ta film and the ITO film, the interface resistance between the Ta film and the Ti film and the interface resistance between the Ti film and the ITO film can be reduced. Therefore,
The resistance (including the resistance at the end) of the wiring from the output terminal of the flexible wiring board to the display area can be stabilized lower than in the conventional case. Therefore, good display quality can be obtained.

According to the third aspect of the present invention, since the Ti film is provided in at least a part of each of the first and second wiring patterns of the display substrate, the output terminal of the flexible wiring board is provided. From the first wiring to the input electrode of the driving IC (including the resistance at the end),
And the resistance (including the resistance at the end) of the second wiring from the output side electrode of the driving IC to the display area.
Can be stabilized lower than before. Therefore, good display quality can be obtained.

In the mounting structure of the display substrate according to the present invention, the ITO film of the first wiring and the output electrode of the driving IC, and the ITO film of the second wiring and the driving I / O.
Since the input electrode of C is connected via the anisotropic conductive film, the lower surface of the driving IC (chip) can be protected by the anisotropic conductive film. Therefore, a separate driving IC
High reliability can be obtained without applying a sealing resin.

In the display substrate according to the fifth aspect, at least at the end of the first wiring on the substrate peripheral side and at the end of the second wiring on the display region side, the ITO film is removed and the tantalum is removed. Since the molybdenum film is provided on the film, the connection resistance between the output side electrode and the input side electrode (generally made of Au) of the driving IC can be further reduced. Claim 1
As in the case of the display substrate described above, it can be manufactured with a high yield, and a good display quality can be obtained after mounting. In addition, it is possible to cope with higher definition of the display in the future.

In the mounting structure of the display substrate according to the present invention, the molybdenum film allows the first wiring to have a peripheral portion of the substrate, a second wiring having a display region, and an output side of the driving IC. The connection resistance between the electrode and the input side electrode can be further reduced.
Therefore, the resistance (including the resistance at the end) of the first wiring from the output terminal of the flexible wiring board to the input side electrode of the driving IC, and the resistance from the output side electrode of the driving IC to the display area. Up to the second wiring (including the resistance at the end). Therefore, good display quality can be obtained, and the reliability of the connection can be improved.

In the display substrate mounting structure of the present invention, the end of the first wiring on the substrate peripheral side and the second wiring are formed by a paste material containing silver or an alloy of silver and palladium as conductive particles. The connection resistance between the display area side end and the output side electrode and the input side electrode of the driving IC can be further reduced.
Therefore, the resistance (including the resistance at the end) of the first wiring from the output terminal of the flexible wiring board to the input side electrode of the driving IC, and the resistance from the output side electrode of the driving IC to the display area. Up to the second wiring (including the resistance at the end). Therefore, good display quality can be obtained, and the reliability of the connection can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a cross section of a main part of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating an entire liquid crystal display device mounted by a COG method.

4 is a diagram showing a cross section of a peripheral portion of the liquid crystal display device of FIG.

FIG. 5 is a diagram illustrating an entire liquid crystal display device mounted by a general mounting method.

6 is a diagram showing a cross section of a peripheral portion of the liquid crystal display device of FIG.

[Explanation of symbols]

 1, 1 'Liquid crystal display panel 21 Lower substrate 24 Driving ICs 46a, 66a First wiring 46b, 66b Second wiring 28a Output electrode 28b Input electrode 29 Ta film 30 ITO film 33 Flexible wiring board 35 Output terminal 36, 41 Anisotropic conductive film 37 Flexible wiring board base material 40 Ti film 42 Insulating film 60 Mo film 61 Ag / Pd paste material 62 Sealing resin

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasunobu Tagusa 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-3-12638 (JP, A) JP-A-4 -93927 (JP, A) JP-A-4-177224 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1345 G09F 9/00 348

Claims (7)

(57) [Claims] 1. A display substrate for constituting a part of a flat panel display device, comprising a wiring on a substrate surface for transmitting a signal from a peripheral portion of the substrate surface to an internal display area. In the substrate, the wiring pattern is formed of a two-layer film including a tantalum film provided in contact with the substrate surface and a tin-added indium oxide film provided on the tantalum film. In at least a part of the region, a titanium film is provided between the tantalum film and the tin-added indium oxide film, and an insulating film is provided on the tin-added indium oxide film in the region where the titanium film is provided. A display substrate, wherein the insulating film is removed in a region of the two-layer film where the titanium film is not provided. 2. The display terminal according to claim 1, wherein an output terminal of a flexible wiring board on which a driving IC for generating the signal is mounted is connected to a portion of the wiring at the peripheral portion. A mounting structure for a display substrate. 3. A first wiring comprising the display substrate according to claim 1, wherein the wiring has a pattern extending from the display region to the peripheral portion, and has a region provided with the titanium film; A second wiring having a pattern extending toward the periphery of the substrate at a position closer to the periphery of the substrate than the first wiring, and a second wiring having a region in which the titanium film is provided; The output side electrode of the driving IC for generating the signal is connected to the portion, and the input side electrode of the driving IC is connected to the end of the second wiring on the display area side. An output terminal of a flexible wiring board for supplying an input signal to the driving IC, is connected to an end of the wiring on the peripheral side of the substrate. 4. The mounting structure of a display substrate according to claim 3, wherein the tin-added indium oxide film of the first wiring, the output electrode of the driving IC, and the second wiring are connected to each other. A mounting structure for a display substrate, wherein the tin-added indium oxide film and the input electrode of the driving IC are connected via an anisotropic conductive film. 5. The display substrate according to claim 1, wherein the wiring has a pattern extending from the display region to the peripheral portion, and a first wiring having a region provided with the titanium film; A second wiring having a pattern extending toward the periphery of the substrate from the first wiring to the periphery of the substrate, and a second wiring having a region in which the titanium film is provided; at least an end of the first wiring on the periphery of the substrate; And a molybdenum film provided on the tantalum film by removing the tin-added indium oxide film at a portion and at an end of the second wiring on the display region side. 6. The display substrate according to claim 5, wherein an output-side electrode of a driving IC for generating the signal is connected to the molybdenum film at an end of the first wiring near the substrate. On the other hand, an input-side electrode of the driving IC is connected to the molybdenum film at an end of the second wiring on the display region side, and the driving electrode is connected to an end of the second wiring on the peripheral side of the substrate. A display substrate mounting structure, wherein an output terminal of a flexible wiring board for supplying an input signal to a display IC is connected. 7. The mounting structure of a display substrate according to claim 6, wherein the molybdenum film at the end of the first wiring on the substrate peripheral side, the output electrode of the driving IC, and the second electrode. That the molybdenum film at the end of the wiring on the display region side and the input electrode of the driving IC are connected via a paste material containing silver or an alloy of silver and palladium as conductive particles. Characteristic display board mounting structure.