JPH0229632A - Active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To simplify a manufacturing process, to reduce a step difference of a gate electrode, and also, to sufficiently lower a resistance of a scan bus line by a one-layer structure by forming the gate electrode of a thin film transistor and the scan bus line from which the gate electrode is led out by a film obtained by forming opaquely the same transparent conductive material as that of a picture element electrode. CONSTITUTION:A gate electrode G and a scan bus line SB from which the gate electrode G is led out are constituted of a film obtained by forming opaquely a transparent conductive material of the same material as that of a picture element electrode E. That is, the picture element electrode E, the gate electrode G and the scan bus line SB are constituted of a film consisting of such a transparent conductive material as an ITO, the picture element electrode E uses a transparent conductive film 2 as it is, and the gate electrode G and the scan bus line use an opaque film 2'. In such a way, a resistance of the scan bus line can also be set to a sufficiently low value for practical use by a one-layer constitution, the step difference of the gate electrode G and the scan bus line becomes small and the film forming process is decreased by one process, therefore, the manufacturing process is facilitated.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to provide an active matrix liquid crystal display device that satisfies required characteristics and is easy to manufacture. a plurality of pixel electrodes made of a transparent conductive material arranged in a row, a thin film transistor arranged in correspondence with the pixel electrode, and a plurality of scan canvas lines arranged in parallel in the row or column direction of the matrix. In the liquid crystal display panel, the gate electrode of the thin film transistor and the scan canvas line from which the gate electrode is derived are formed from a film made of the same transparent conductive material as the pixel electrode and made opaque.

[Industrial application field]

The present invention relates to an active matrix liquid crystal display device.

Active matrix liquid crystal display devices are thin and capable of producing high-quality, full-color images, so their development is progressing in various fields and has almost reached the stage of practical use. The problem is that the manufacturing process is complicated, resulting in a decrease in yield, and studies are underway to simplify the manufacturing process in order to solve this problem.

[Conventional technology]

In a conventional active matrix liquid crystal display device, as shown in the exploded view of one pixel in FIG.
It was formed to have a two-layer structure of a transparent conductive film 2 made of a transparent conductive material, which is the same material as the pixel electrode E, and a metal film 3. To form such a laminated structure, first, the transparent conductive film 2 and the metal film 3 are laminated, and this is patterned to exclude the gate electrode G portion, the scan canvas line (not shown) portion, and the pixel electrode E portion. After removing the other portions, the metal film on the pixel electrode E portion is removed.

As described above, in the conventional active matrix liquid crystal display device, since the gate electrode G has a two-layer structure, the difference in level between the gate electrode G and the scan canvas line and the vicinity thereof becomes large. Further, there is a problem in that a process for creating a laminated structure is required, which complicates the manufacturing process.

Therefore, it is also conceivable to configure the gate electrode G and the scan canvas line with only one layer of transparent conductive film. This configuration simplifies the manufacturing process, but since the channel part of the thin film transistor (TPT) transmits light, the TP
The photoleakage current of T increases.

[Problem to be solved by the invention]

As mentioned above, in conventional active matrix liquid crystal display devices, attempts to satisfy various required characteristics complicate the manufacturing process, and attempts to simplify the manufacturing process cause problems in characteristics.

An object of the present invention is to provide an active matrix liquid crystal display device that satisfies required characteristics and is easy to manufacture.

[Means to solve the problem]

FIG. 1 shows the configuration of the present invention.

As shown in the figure, in the present invention, the gate electrode G and the scan canvas line SB from which the gate electrode G is derived (see Figure 2) are made of a film made of an opaque transparent conductive material, which is the same material as the pixel electrode E. composition.

That is, the pixel electrode E, the gate electrode G, and the scan canvas line SB are composed of a film made of a transparent conductive material such as ITO, the pixel electrode E uses the transparent conductive film 2 as is, and the gate electrode G and the scan canvas line In this example, a film 2' made of the transparent conductive film described above is made opaque.

[For production]

A film made of a transparent conductive material such as ITO is easily made metallic by hydrogen plasma treatment. This metallic film turns black and becomes non-transparent, and its resistance value is also about 1 compared to before the plasma treatment.
/2.

Therefore, even if the gate electrode G is composed of only this film, no light will pass through the channel part, and the resistance of the scan canvas line can be made to a sufficiently low value for practical use with a single layer structure. , the step difference between the gate electrode G and the scan canvas line becomes smaller, and the number of film forming steps is reduced by one, so that the manufacturing process becomes easier.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2(a) to (1)). In addition, Fig. 2 (11~(pi is each (a)
) to (h) are main part sectional views taken along the line nn arrow.

(See FIG. 2(a), (11)) A film 5 made of a transparent conductive material, for example, an ITO film 2, is deposited on a transparent insulating substrate 2, for example, a glass substrate l, with a thickness of approximately 30 to 1,100 mm.
A film is formed to a thickness of n. Next, an image siliversal photoresist (manufactured by Sibley) is applied on top of this, and this is patterned to form the pixel electrode formation area, the gate electrode,
Resist film 11 covering the scan canvas line forming area
．． 11' is formed.

[See FIGS. 2(b) and (J)] Next, the portion of the resist film 11.11° indicated by diagonal lines downward to the right in the figure, that is, the resist film 11 covering the pixel electrode formation region, is exposed to light. After that, baking is performed at a temperature of about 120° C. for about 30 minutes.

The above baking performed on the image reversal photoresist film after exposure is called reversal baking.

An image reversal photoresist is originally a positive type, but when subjected to reversal baking, the exposed area becomes insoluble in a developer like a negative type. Therefore, this step makes the resist film 11 insoluble in the developer.

Thereafter, the entire surface of the resist film 11.11'' is exposed to light to make the resist film 11'' covering the gate electrode and scan canvas line formation region soluble in a developer.

[See FIGS. 2(C) and (k)] Using the resist film 11.11° as a mask, the exposed portion of the ITO film 2 is removed by wet etching to remove the ITO film 2 of the pixel electrode portion and the gate electrode portion. After forming the ITO film 2'' on the scan canvas line portion, the resist film 1
1. Perform 11' development. As a result, only the resist film 11 on the pixel electrode formation region remains, and the resist film 11' is removed.

[See Figure 2(d), +11] Next, using this resist film 11 as a mask, the ITO film 2 was applied at a temperature of about 120° C. and a reaction pressure of about 3 Torr.

Hydrogen plasma treatment is performed under conditions of high frequency power of approximately 30W. As a result, the transparent conductive material ITO becomes metallic and blackened, and the resistance value decreases to approximately 1/2. Here, a gate electrode G and a scan canvas line SR are formed.

After this, the resist film 11 is removed.

[See Figures 2(e) and (m)] Next, a gate insulating film with a thickness of about 100 to 300 nm is formed.
A 5iNX film 4 of
1100n a-3t (amorphous silicon) layer5.
n″a-3 doped with P (phosphorus) as a contact layer
The i-layer 6 is laminated to a thickness of approximately 30 nm.

(See FIGS. 2(f) and (n)) Next, the above n"a-3i layer 6 r a S 1 layer 5
Etching is performed on the SiN film 4 using a resist film (not shown) as a mask to form the laminated film in the element forming portion T and the data bus 94208 portion, and then the resist film is removed.

[See FIGS. 2 (A) and (O)] A metal film such as an AI (aluminum) film 7 is formed to a thickness of about 300 to 11000 nm.

[See FIGS. 2(h) and (P)] The Al film 7 is patterned to remove unnecessary parts,
Drain electrode, data bus line DB.

and source electrodes S are formed, and a part of the n"a-3i layer 6 is removed to complete the active matrix type liquid crystal display device of this embodiment.

In this embodiment described above, since both the gate electrode G and the scan canvas line SB are made of only the blackened ITO film, the step difference becomes small and the process of laminating and etching the films becomes unnecessary. The manufacturing process is simplified, the resistance value of the pass line is sufficiently low for practical use, and no light leakage current occurs because no light passes through the channel portion.

〔Effect of the invention〕

As described above, according to the present invention, the manufacturing process is simplified, the step difference in the gate electrode is small, and the resistance of the scan canvas line can be made sufficiently low with a single layer structure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of the present invention, FIGS. 2(a) to (P) are explanatory diagrams of one embodiment of the present invention, and FIG. 3 is an explanatory diagram of the conventional TPT configuration. In the figure, 1 is a glass substrate, 2 is a transparent conductive material film, 2
゛ is an opaque transparent conductive material film, 3 is a metal film such as Cr, 4 is a gate insulating film, 5 is an active semiconductor layer, 6 is a contact layer, 7 is a metal film such as A1, G is a gate electrode, and E is a metal film such as A1. The pixel electrode, SB, is a scan bar.Fig.Explanatory diagram of the configuration of the conventional TPT.Fig.Explanatory diagram of the present invention-embodiment.m2 (Part 2)

Claims (1)

[Claims] A plurality of pixel electrodes (E) made of a transparent conductive material arranged in a matrix on a transparent insulating substrate (1), thin film transistors arranged in correspondence with the pixel electrodes, and rows or columns of the matrix. In the liquid crystal display panel including a plurality of scan canvas lines (SB) arranged parallel to the direction, the gate electrode (G) of the thin film transistor
and a scan canvas line from which the gate electrode is derived (
An active matrix type liquid crystal display device, characterized in that SB) is formed from a film made of the same transparent conductive material as the pixel electrode (E) and made opaque.