JP2695424B2 - Liquid crystal display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid crystal display device, and in particular, in a liquid crystal display device using a TFT array, a disconnection defect of a gate electrode wiring when an area and a resolution are increased. , And reduction of short-circuit defects at the intersection of the gate electrode wiring and the source electrode wiring.

[Prior Art] A liquid crystal display device is usually constructed by a method in which a display material such as liquid crystal is sandwiched between two opposed substrates and a voltage is applied to the display material. At this time, pixel electrodes arranged in a matrix are provided on at least one substrate, and an active element having a non-linear characteristic such as a FET (field effect transistor) is provided for each pixel in order to selectively operate these pixels. There is.

Conventional devices of this type are shown in FIGS. 5, 6, and 7.
FIG. 5 is a partial plan view of a TFT array of a liquid crystal display device formed by a conventional method, and FIGS. 6 and 7 are DD ′ section and E- section in FIG. 5, respectively. It is sectional drawing of E'part. In the figure, 1 is a transparent insulating substrate, 2 is a gate electrode and wiring, 3 is a source electrode and wiring, 4 is a drain electrode, 5 is a pixel electrode, 6 is a gate insulating film, 7 is a semiconductor layer, 8 is a passivation film, 9 Is a light-shielding film, 10 is a contact portion between the drain electrode and the pixel electrode, and 11 is a gate wiring formed simultaneously with the pixel electrode.

Generally, a gate electrode of a TFT array used in a liquid crystal display device or the like is usually made of a refractory metal such as Cr having high heat resistance, but in order to achieve a large screen and high resolution, signal attenuation due to wiring resistance, In order to prevent delay and the like, it is necessary to increase the film thickness and reduce the resistance. However, when the film thickness is increased, refractory metal such as Cr has a high probability of cracking due to the stress of the film. Further, there is a defect that disconnection occurs due to patterning failure due to dust or the like due to high resolution, fine wiring accompanying screen enlargement, and increase in wiring length, leading to a reduction in yield. In order to overcome such drawbacks, the conventional TFT array of the liquid crystal display device is shown in FIG.
As shown in FIGS. 6 and 7, at the same time when the first pixel electrode 5 is formed, the gate electrode is made of the transparent conductive film and the gate wiring is formed.
A method has been performed in which 11 is formed, and then the original gate electrode and the wiring 2 are formed on the gate wiring 11 so as to cover the gate wiring 11 to form the gate wiring into two layers.

[Problems to be solved by the invention]

As described above, the conventional liquid crystal display device has two gate wirings.
Since the gate wiring made of the pixel electrode material exists at the intersection of the gate wiring and the source wiring by layering, the short circuit between the gate wiring and the source wiring due to the influence of dust in the pixel electrode material or the step However, there is a problem in that the yield occurs and the yield decreases.

The present invention has been made in order to solve the above problems, and disconnection of the gate wiring without increasing the line short-circuit defects between the gate wiring and the source wiring at the intersections of the source wiring and the gate wiring. An object of the present invention is to provide a liquid crystal display device having a TFT array capable of reducing defects.

[Means for solving the problem]

In the liquid crystal display device according to the present invention, the gate electrode wiring of the TFT array substrate is provided with a transparent conductive film formed on the same plane as the pixel electrode except for the intersection of the gate electrode wiring and the source electrode wiring. It has a two-layer structure of a conductive film of a gate electrode wiring material, and has a single-layer structure of a conductive film at the intersection of the gate electrode wiring and the source electrode wiring.

[Action]

In the liquid crystal display device according to the present invention, the gate wiring has a two-layer structure of a transparent conductive film and a conductive film which are formed on the same plane as the pixel electrode except the intersection of the gate wiring and the source wiring. Since the single layer structure of the conductive film by the original gate wiring is formed at the intersection of the wiring and the source wiring, there is no increase in short circuit between the gate wiring and the source wiring at the intersection of the gate wiring and the source wiring. It is possible to reduce disconnection of gate wiring,
The yield is improved.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a TFT of a liquid crystal display device according to an embodiment of the present invention.
Partial plan views of the array, FIGS. 2, 3, and 4 are first
The cross-sectional views of the AA 'portion, the BB' portion, and the CC 'portion of the drawing are respectively shown. In the figure, the same reference numerals as those in FIG. 5 indicate the same portions, and 11 is a gate wiring formed at the same time as the pixel electrode in a portion other than the intersection of the gate wiring and the source wiring.

 Hereinafter, the manufacturing method of this embodiment will be described.

First, on a transparent insulating substrate 1 such as glass, ITO (Indium Ti
n Oxide; transparent conductive film such as indium tin oxide film)
(Electron Beam) Deposited by a vapor deposition method or the like. Then, the pixel electrode 5 and the gate wiring 2 are formed by a method such as photolithography.
An island-shaped gate wiring 11 is formed at a portion other than a portion slightly wider than the intersection between the gate wiring 11 and the source wiring 3.
Next, a metal such as Cr is deposited by a method such as sputtering to form the gate electrode and the gate wiring 2 on the gate wiring 11 made of ITO in a larger size. Next, a silicon nitride film or a silicon oxide film to be the gate insulating film 6 and hydrogenated amorphous silicon (a-Si; H) to be the semiconductor layer 7 are continuously deposited on the entire surface by plasma CVD or the like. Next, the semiconductor layer 7 is formed in an island shape, and a contact hole for connecting the pixel electrode 5 to the gate insulating film 6 is formed. Next, a metal film such as Al is deposited to form the source electrode and the source wiring 3 and the drain electrode 4. Next, a silicon nitride film, a silicon oxide film, or the like is deposited as the passivation film 8. Then, the gate insulating film 6 and the passivation film 8 on the pixel electrode 5 are removed collectively.
Then, Al or the like is deposited above the portion where the semiconductor layer 7 is formed to form the light shielding film 9.

A display material such as liquid crystal is sandwiched between the TFT array substrate thus formed and a counter substrate having a transparent conductive film, a color film, etc., to complete the liquid crystal display device of the present invention.

In the liquid crystal display device including the TFT array having the above-described configuration, the gate wiring is formed into two layers at all portions except the intersection of the gate wiring 2 and the source wiring 3, and patterning is performed separately. Even if a patterning defect occurs due to cracks, dust, or the like in any of the wirings, the connection is made in the other wiring, and a disconnection defect does not occur. Moreover, since the intersection of the gate wiring 2 and the source wiring 3 has the single-layer structure of the conventional gate wiring 2, short-circuit defects between the gate electrode wiring and the source electrode wiring due to dust on the gate wiring 11 do not occur. . Therefore, according to the present invention, it is possible to obtain a large-area, high-resolution liquid crystal display device with extremely few display defects with high yield.

Although the hydrogenated amorphous silicon film is used for the semiconductor layer 7 in the above-mentioned embodiment, it may be a polycrystalline silicon film.

Further, in the above-mentioned embodiment, Cr is used as the conductive film of the gate electrode wiring 2. However, in addition to Cr, Ta, Ti, Ni-Cr, M
A metal composed of o, Al-Si or the like may be used.

Further, in the above embodiment, the semiconductor layer 7 made of TFT is formed in the vicinity of the intersection of the source electrode wiring 3 and the gate electrode wiring 2.
Although it is configured to provide one, a plurality of may be provided in parallel.

〔The invention's effect〕

As described above, according to the liquid crystal display device of the present invention, the gate wiring is formed in the island-shaped image electrode material made of the transparent conductive film in a portion other than the intersection of the gate wiring and the source wiring, and then the conductive film is used. By forming the original gate electrode and wiring, the gate wiring has a two-layer structure in the portion other than the intersection of the gate wiring and the source wiring, and the gate wiring has a single layer in the intersection of the gate wiring and the source wiring. Since it has a layered structure, it is possible to prevent short-circuiting between lines at the intersection of the gate wiring and the source wiring, reduce the disconnection of the gate wiring, and achieve high yield.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a TFT array of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA ′ in FIG. 1, and FIG. 3 is a cross section taken along the line BB in FIG. 4 is a sectional view taken along line CC 'of FIG. 1, FIG. 5 is a partial plan view of a TFT array of a conventional liquid crystal display device, and FIG. 6 is a sectional view taken along line D- of FIG.
FIG. 7 is a sectional view of the section D ', and FIG. 7 is a sectional view of the section EE' in FIG. 1 is a transparent insulating substrate, 2 is a gate electrode and wiring, 3 is a source electrode and wiring, 4 is a drain electrode, 5 is a pixel electrode,
Reference numeral 6 is a gate insulating film, 7 is a semiconductor layer, 8 is a passivation film, 9 is a light-shielding film, 10 is a contact portion between the drain electrode and the pixel electrode, and 11 is a gate wiring formed simultaneously with the pixel electrode. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taro Maejima 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Material Research Laboratory (72) Inventor Masahiro Hayama 8-1-1 Tsukaguchi Honmachi, Amagasaki City, Hyogo Prefecture No. 1 Mitsubishi Electric Corp. Material Research Laboratory (56) Reference JP-A 64-29819 (JP, A) JP-A 63-9977 (JP, A) JP-A 62-288882 (JP, A) JP-A 62-205390 (JP, A) JP-A-62-65468 (JP, A) JP-A-61-105582 (JP, A)

Claims (1)

(57) [Claims] 1. A plurality of gate electrode wirings, a plurality of source electrode wirings formed so as to intersect with the gate electrode wirings, and an intersection portion of the gate electrode wirings and the source electrode wirings on a transparent insulating substrate. TFT array substrate including at least one thin film transistor (hereinafter abbreviated as TFT) having a non-linear characteristic, which is disposed in the vicinity of the TFT, and a display electrode which is a transparent conductive film connected to the drain electrode of the TFT. And a liquid crystal display device having a counter electrode substrate having a transparent conductive film, and a liquid crystal material sandwiched between the TFT array substrate and the counter electrode substrate, wherein the gate electrode wiring of the TFT array substrate is The transparent conductive film formed on the same plane as the display electrode, and the transparent conductive film and the transparent insulating film are formed on a portion other than the intersection of the gate electrode wiring and the source electrode wiring. A liquid crystal having a two-layer structure with a conductor film continuously formed on a flexible substrate, and having a single-layer structure of the conductor film at the intersection of the gate electrode wiring and the source electrode wiring. Display device.