JP3195837B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display comprising a thin film transistor array and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional thin film transistor (hereinafter, referred to as a thin film transistor).
It is called TFT. 2) The method of manufacturing the array is shown in the order of steps. First, as shown in FIG. 2A, an SiO ₂ film 3 is formed as an undercoat film on a glass substrate 31 as an insulating transparent substrate.
2 is formed on the entire surface. Next, an aluminum film or an alloy film thereof is pattern-formed as a first metal film to be the gate electrode 33.

[0003] Next, as shown in FIG.
For example, an AlOx, TaOx or SiNx film is formed as 4. Next, an SiNx film is formed as the channel protection film 35, and then a silicon semiconductor layer 36 is formed. Then, an n +: silicon film 37 is patterned on the silicon semiconductor layer 36.

[0004] Next, as shown in FIG.
After forming the contact window 38 in order to obtain a pull-out and part of the pixel electrode 39 and the TAB mounting electrode 40
An ITO film, which is a transparent conductive film, is patterned.

Next, as shown in FIG. 1D, a gate electrode 33 is drawn out through a contact window 38 by patterning a second metal film to be a source / drain electrode 41. That is, the gate electrode 33 and the source / drain electrode 41 are connected and converted to the lower ITO film 40 and are led out as the TAB mounting electrode 40 to the outside. Finally, an insulating protective film 42 is formed by patterning, and a thin film transistor array substrate is completed.

In the above conventional example, the pixel electrode 39 is formed before the source / drain electrode 41 is formed. However, the pixel electrode 39 may be provided before the gate electrode 33 is formed or after the source / drain electrode 41 is formed. However, even in such a TFT array, external lead's gate electrode 33, or is connected to the metal film for the source and drain electrodes 41 through the contact windows 38, further being connected converted to TAB mounting electrodes 40.

[0007]

As described above [0008], lead to the electrode in a conventional liquid crystal display device, the external lead and portions other metal film of the gate electrode, i.e. via the source electrode metal film, and further a gate TAB for both electrode and source electrode
It is converted into a mounting electrode film and indirectly drawn out. Therefore, the contact window formation step as the gate electrode pull-out is required, pinholes therefore, the resist in forming a contact window -
If there is a hole, the probability of occurrence of interlayer short-circuit failure increases. Also,
Although an ITO film is used as a TAB mounting electrode,
Since the mounting resistance of the O film is as high as several hundred ohms / square, the pattern size is large, and there is a big problem in reliability.

An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a liquid crystal display device which can eliminate a contact window forming step and can reduce the number of steps, and a method of manufacturing the same.

[0009]

Means for Solving the Problems] To achieve the above object, a liquid crystal display device of the present invention, the signal input external extraction electrode of the gate electrode and the source electrode of the thin film transistor included in the thin-film transistor array of the other metal film With a liquid crystal display device that is directly drawn out without being converted through
And an electrode configuration of a source electrode of the thin film transistor.
And a lower metal film made of the same metal as the gate electrode.
A laminated structure of the upper-layer metallic film made of a corrosion resistant metal, the is the upper-layer metallic film of the multilayer structure is removed in the external lead-out portion of the source electrode is obtained by forming a contact window for the external lead.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention, by the above configuration, by each external lead portion of the gate electrode and the source electrode are drawn directly outside without being converted via the other metal film, and unnecessary contact window formation process, step Reduction can be achieved. Further, since the electrode material for mounting the TAB can be formed of the same material as the metal film for the gate electrode and the source / drain electrodes, particularly, an aluminum film or an alloy film thereof, the mounting resistance is reduced and the size of the electrode pattern for mounting the TAB is reduced. it can.

[0011]

EXAMPLES The following is a description about the real施例of the present invention. So
Before development of the present invention prior to the figure
1 and FIG. (Prior Development Example) As shown in FIG. 1A, as a first step, an SiO ₂ film 12 is formed as an undercoat film on an entire surface of a glass substrate 11 as an insulating transparent substrate. Next, the substrate 11
As a second step, an aluminum film or an alloy film thereof is patterned as a first metal film to be the gate electrode 13. At this time, the TAB mounting electrode 13a on the gate side is
Drawn as extension end of the Gate wiring, the gate electrode 1
3 is formed of the same metal material.

Next, as shown in FIG. 2B, as a third step, AlOx, TaOx or SiNx is used as in the conventional example.
, A channel protective film (interlayer insulating film) 15 of SiNx, and a silicon semiconductor layer 16 are formed. 4th
As a step, the channel protective film 15 on the gate electrode 13 is formed.
Is patterned. Next, as a fifth step, an n +: silicon film 17 is formed, and the n +: silicon film 17 and the silicon semiconductor layer 16 are formed so that a TFT will be formed in the future.
Is patterned.

Next, as shown in FIG. 1C, as a sixth step, a transparent conductive film ITO is formed as the pixel electrode 18 and a pattern is formed.

Next, as shown in (d), a second metal film to be the source / drain electrodes 19 is formed in a pattern as a seventh step. At this time, as shown in FIG. 2 , the source-side TAB mounting electrode 19a is also drawn out to the extended end of the source wiring, and is formed of the same metal material as the source / drain electrode 19.

In an eighth step, the insulating protective film 20 is formed.
Is formed on the TAB mounting electrode 13a on the gate side by forming a channel protection film 15 on the gate-side TAB mounting electrode 13a.
And a SiNx film as the insulating protective film 20 is mounted,
On the TAB mounting electrode 19a on the source side, a SiNx film as the insulating protective film 20 is mounted.

Finally, as a ninth step, an insulating protective film 20 is formed.
Is patterned. At this time, the channel protective film 15
And the SiNx film as the insulating protection film 20 is made of, for example, S
The individual electrodes are exposed by being removed by the dry etching using the F ₆ gas, and the TFT array substrate is completed.

Next , a second prior development example will be described. The TFT array substrate in this prior development example has the same configuration as that of the above first development example, but the gate electrode 13 and the source / drain electrode 19 are formed of the same metal film, for example, an aluminum film or an alloy film thereof. . Therefore, the gate-side and source-side TAB mounting electrodes 13a and 19a are both formed of an aluminum film or an alloy film thereof. And these destinations
In a row development example, a transparent conductive film as a pixel electrode was used.
Direct contact between the ITO film and the aluminum film
For example, when coexisting with an electrolytic solution such as a developer,
Reaction occurs and dissolution of the aluminum film and reduction of the ITO film
Blackening may occur. And aluminum film
Dissolution causes disconnection, and blackening of the ITO film permeates the pixel electrode.
This leads to a reduction in the rate and causes defects. And al
The problem that the MINOC film generates hillocks when heated
Points also occur.

(Embodiment) The present invention has solved the problems of the above-mentioned prior development examples. That is, in the dry etching in the final step of the preceding development example, when the source / drain electrode 19 is, for example, a single-layer film, only the SiNx film as the insulating protective film 20 is etched to obtain the configuration shown in FIG. Can be However, when the source / drain electrode 19 has a laminated structure of, for example, a Ti / Al film or a Ti / Al alloy film, as shown in FIG. and a this <br/> that can removed by dry etching in g simultaneously by SF6 as an etching gas, it is possible to expose only the lower layer of the aluminum film or an alloy film as the source side TAB mounting electrodes 19a. Therefore, the source / drain electrodes 19
The FT array has a laminated structure of Ti / Al or its alloy film, but has a source-side TAB mounting electrode 19a.
Is formed of the same aluminum film as the gate electrode 13 or an alloy film thereof.

As described in the above paragraph [0006], in the case where the pixel electrode in the thin film transistor array configuration is provided after the formation of the source / drain electrodes,
The ITO film as a pixel electrode is connected to an Al film via a Ti film which is an upper layer film of a source / drain electrode made of a laminated film. Therefore, dissolution of the Al film and blackening of the ITO film due to electrolytic corrosion can be suppressed. Further, the laminated film has an upper layer made of Ti.
Since the hillock phenomenon of the lower Al layer can be suppressed, the problems of the prior development examples can be suppressed or avoided.

[0020]

According to the liquid crystal display device of the present invention as described above, according to the present invention, the signal input external extraction electrode of the gate electrode and the source electrode of the thin film transistor included in the thin film transistor array is not converted through another metal film a liquid crystal display device directly led to the outside, the same as the gate electrode of the electrode structure of the source electrode of the thin film transistor
Metal film made of different metals and upper layer made of corrosion resistant metal
A stacked structure of a metal film, since the contact window for the upper-layer metallic film is removed external lead of the laminated structure in the outer lead portion of the source electrode is formed, the external lead electrode and another metal Eliminates the need for a contact window formation step for conversion through the film,
The number of steps can be reduced.

Further, the TAB mounting electrode is connected to the gate electrode and the
And the same material as the metal film for the source and drain electrodes.
By, for example, aluminum film or its alloy film
By that form in implementation compared to the conventional ITO film resistance
Resistance is reduced, and the electrode pattern for TAB mounting is reduced.
be able to.

Further , the pixel electrode is connected to a source / drain electrode.
In the case of a thin film transistor array configuration provided after pole formation
Is that the ITO film, which is the pixel electrode, is directly
Upper layer metal that is not contacted and constitutes source / drain electrodes
(Ti film), so that the ITO film and aluminum
Of aluminum film by electrolytic corrosion (battery reaction) of aluminum film
Solution and blackening of the ITO film can be suppressed. Further, the Ti film
As the upper metal layer of the source / drain electrodes.
Can suppress the hillock phenomenon of the lower layer Al,
Commercial value as a crystal display device
is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration conceptual diagram showing a step of forming a gate-side TAB mounting portion on an array substrate in a development example developed prior to the present invention.

2 is a cross-sectional configuration conceptual diagram of Ichikatachi formation process of the source-side TAB mounting portion on the array substrate in the same advanced development example.

FIG. 3 shows a source on an array substrate according to an embodiment of the present invention .
FIG. 7 is a conceptual diagram of a cross-sectional configuration in one forming process of a side TAB mounting portion
is there.

FIG. 4 shows a gate-side TAB on an array substrate in a conventional example.
FIG. 5 is a conceptual diagram illustrating a cross-sectional configuration illustrating a process of forming a mounting unit.

DESCRIPTION OF SYMBOLS 11 Glass substrate 12 SiO ₂ film 13 Gate electrode 13 a Gate-side TAB mounting electrode 14 Gate insulating film 15 Channel protective film (interlayer insulating film) 16 Silicon semiconductor layer 17 n +: Silicon film 18 Pixel electrode 19 Source / Drain electrode 19a Source-side TAB mounting electrode 20 Insulation protective film

Continuation of the front page (72) Inventor Toshihiro Nishii 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-1-304427 (JP, A) JP-A-1-217421 (JP, A) JP-A-2-22622 (JP, A) JP-A-4-316022 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1362 G02F 1 / 1345 G02F 1/1343 G02F 1/1333 H01L 29/78

Claims (2)

(57) [Claims] 1. A liquid crystal display device in which each signal input external extraction electrode of the gate electrode and the source electrode of the thin film transistor included in the thin film transistor array is drawn directly outside without being converted via the other metal layer, wherein the gate electrode of the electrode structure of the source electrode of the thin film transistor
From the lower metal film made of the same metal as the pole and the corrosion-resistant metal
The liquid crystal display device has a stacked structure of the upper-layer metallic film, wherein the contact window for the upper-layer metallic film is removed external lead of the laminated structure in the outer lead portion of the source electrode is formed comprising . 2. An insulating substrate comprising SiO2 or TaO
forming an undercoat material of x, forming a gate electrode and a metal film serving as an external lead portion of the gate electrode on the substrate, and forming a gate insulating film, a channel protective film and a silicon semiconductor layer. Patterning a channel protective film on the gate electrode, forming an n +: silicon film on the substrate or implanting an impurity of a phosphorus element, and forming a source / drain electrode and a source electrode on the substrate. The lower metal film made of the same metal as the metal film serving as the lead portion and a corrosion-resistant metal are used.
Forming a metal layer of the laminated structure of an upper metal film that,
An insulating protective film is formed on the substrate, and the respective external lead-out portions of the gate electrode and the source electrode are directly drawn out without being converted via another metal film, and the external lead-out portions of the gate electrode and the source electrode are formed. Forming a contact window for TAB extraction on the upper insulator layer, forming a pixel electrode made of a transparent conductive film, and etching the electrode into a desired shape;
And forming an upper metal layer of the source electrode in the formation of the contact window for leading out the TAB.
A method for manufacturing a liquid crystal display device, comprising removing a film .