JPH10268344A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leakage from being caused between adjacent pixel electrodes by a light shield film without making the manufacturing process complicated by providing the light shield film as a layer below an inter-layer insulating film. SOLUTION: A source signal line 8 is formed as a single layer and the light shield film 11 is formed blow the inter-layer insulating film 12 while covering the source signal line 8 and the channel region 21 of the amorphous Si layer 5 of a TFT 15 and also patterned in the same shape with a channel protection film 10. The source signal line 8 and the channel region 21 of the TFT 15 can, therefore, be shielded from light. Consequently, no light shield film needs to be formed on a color filter substrate, so the color filter substrate can be formed at low cost and the possibility that adjacent pixel electrodes have a leak owing to patterning deviation is eliminated as compared with the formation of the light shield film on the pixel electrode, thereby improving the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device having a light-shielding film on a TFT substrate and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a liquid crystal display device, a so-called active matrix type liquid crystal display device in which a plurality of gate signal lines and source signal lines orthogonal to each other, pixel electrodes in a matrix, and TFTs as switching elements are formed on a substrate. It has been known.

FIG. 3A is a plan view of a TFT substrate used in this conventional active matrix type liquid crystal display device. In the figure, 108 is a pixel electrode, 120 is a gate signal line, 114 is a source signal line, 112 is an auxiliary capacitance line, and 113 is a TFT. Also, FIG.
(A) is a CC cross-sectional view. In FIG.
Is a light-transmitting substrate such as glass, and 102 is a gate signal line 120.
, A gate insulating film 103, an amorphous Si layer 104, source and drain electrodes 105 and 106 each made of an n ⁺ type amorphous Si layer, a transparent conductive film 107 such as ITO, 1
09 and 110 indicate metal layers, and 111 indicates a channel protective film. Note that the transparent conductive film 107 and the metal layer 109 are provided to be stacked in the same shape and serve as a source signal line 114.

Since the pixel electrode 108 is separated from the gate signal line 120 and the source signal line 114, it is necessary to prevent light from passing through this gap. Also,
When light enters the channel region 121 of the amorphous Si layer 104 of the TFT 113, an off current is generated and the characteristics of the TFT are deteriorated.
Need to be shielded from light. Therefore, conventionally, a light-shielding film is provided on a color filter substrate provided opposite to a TFT substrate and provided with a counter electrode and a micro color filter.

However, in recent years, in order to reduce the cost of the color filter substrate, a method of forming the light shielding film 115 on the TFT substrate side as shown in FIGS. 4A and 4B has been known. FIG. 4B is a sectional view taken along line DD in FIG. 4A. In FIG. 4, the same members as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

With such a structure, it is not necessary to form a large light-shielding film in consideration of a parallax shift and an alignment margin at the time of bonding as compared with a case where a light-shielding film is provided on the color filter substrate side. The rate can be increased to the limit.

In recent years, an active matrix type liquid crystal display having the structure shown in FIG. 5 has been developed with the aim of further improving the aperture ratio. FIG. 5 (a) shows the T matrix used in this active matrix type liquid crystal display device.
It is a top view of an FT board | substrate, (b) of FIG. 5, (c) is EE sectional drawing and FF sectional drawing, respectively. In FIG. 5, reference numeral 116 denotes a connection electrode made of ITO or the like, which is formed up to the auxiliary capacitance wiring 112. Reference numeral 117 denotes an interlayer insulating film, and reference numeral 118 denotes a contact hole.
The pixel electrode 108 is formed on the interlayer insulating film 117, and is connected to the connection electrode 116 at a contact hole 118.

In the case of such a structure, the gate signal line and the source signal line and the pixel electrode can be formed to slightly overlap each other, so that the area between the gate signal line and the source signal line and the pixel electrode is shielded from light. There is no need. Further, since the gate signal line is usually formed of a light-shielding metal, it is not necessary to newly form a light-shielding film on the gate signal line. Further, the source signal line 114 is also formed of two layers, one of which is formed of the light-blocking metal 109,
It is not necessary to newly form a light shielding film also on the source signal line.
Therefore, in order to shield the channel region from light, the pixel electrode 1
The light-shielding film 115 may be formed only in a predetermined area on the area 08.

[0009]

However, in the case of the liquid crystal display device having the structure shown in FIG. 5, the transparent conductive film 107 to be the source signal line 114 and the connection electrode 116 are formed and patterned, and are formed thereon. Metal layers 109 and 11
It is necessary to perform the film formation and patterning of 0 in a separate process, and there is a problem that the manufacturing process becomes considerably complicated. This is because the transparent conductive film 10 serving as the source signal line 114 is
7 and the metal layer 109 have the same shape,
This is because the pattern 6 and the metal layer 110 cannot be collectively patterned because they do not have the same shape.

Further, since the light-shielding film 115 is formed in a predetermined region on the pixel electrode 108, the manufacturing process is further complicated, and when the light-shielding film 115 is misaligned, the adjacent pixel electrode 108 leaks. There was a problem of doing it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In a liquid crystal display device having a high aperture ratio and a light-shielding film on a TFT substrate, the manufacturing process is not complicated and adjacent pixels can be formed. An object of the present invention is to provide a liquid crystal display device that can prevent a leak between electrodes by a light shielding film.

[0012]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising a plurality of gate signal lines orthogonal to each other;
An interlayer insulating film including a source signal line and a matrix-like switching element, and having a contact hole so as to cover the gate signal line, the source signal line, and the switching element is provided. The interlayer insulating film is provided on the interlayer insulating film through the contact hole. A liquid crystal display device having a pixel electrode connected to the switching element, wherein a light-shielding film is provided on the source signal line and the switching element and below the interlayer insulating film. Things.

Therefore, it is not necessary to form a light-shielding film on the color filter substrate, so that the color filter substrate can be formed at a low cost. Leakage does not occur in adjacent pixel electrodes due to the displacement, and reliability can be improved.

According to a second aspect of the present invention, there is provided a liquid crystal display device comprising:
2. The liquid crystal display device according to claim 1, wherein the switching element is a thin film transistor, a channel protection film is formed in a region including a portion immediately above a channel region of the thin film transistor, and the channel protection film and the light shielding film are the same. It is characterized by being patterned into a shape.

Therefore, the light-shielding film can be formed on the TFT substrate without greatly increasing the manufacturing process.

Further, by forming the light shielding film also on the source signal line, the source signal line can be formed only of the transparent conductive film, and the manufacturing process can be shortened.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising the steps of sequentially forming a gate signal line, a gate insulating film, a switching element, and a source signal line on a substrate; And a step of continuously forming a light-shielding film and patterning the same using the same resist pattern.

Therefore, the manufacturing process can be greatly reduced as compared with the conventional case where the protective film and the light shielding film are formed in separate steps.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
This will be described below with reference to FIG. FIG. 1A is a plan view of a TFT substrate used in the liquid crystal display device according to the present embodiment. FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, and FIG. 1) shows a cross-sectional view taken along the line BB of FIG. In the figure, 1 is a light-transmitting substrate such as glass, 2 is a gate electrode formed extending from the gate signal line 20, 3 is a capacitor wiring, 4 is a gate insulating film, 5 is an amorphous Si layer, and 6 is a source. Electrode, 7 is a drain electrode, 8 is a source signal line, 9
Is a connection electrode, 10 is a channel protective film, 11 is a light shielding film, 1
2 denotes an interlayer insulating film, 13 denotes a pixel electrode, 14 denotes a contact hole, and 15 denotes a TFT.

As shown in FIGS. 1B and 1C, in the present embodiment, the source signal line 8 is formed in a single layer, and the light shielding film 11 is formed of the source signal line 8 and the TF.
T15 is formed below the interlayer insulating film 12 so as to cover the channel region 21 of the amorphous Si layer 5;
Moreover, it is patterned into the same shape as the channel protective film 10. Therefore, the source signal line 8 and the channel region 21 of the TFT 15 can be shielded from light.

Hereinafter, a method for manufacturing the liquid crystal display device of the present embodiment will be described. First, as shown in FIG. 2A, a gate signal line (not shown) made of metal such as Ta on the light transmitting substrate 1, a gate electrode 2 extending therefrom, and a capacitor wiring 3 is formed and patterned into a predetermined shape.

Subsequently, as shown in FIG.
After a gate insulating film 4 is formed so as to cover the gate signal line and the capacitor wiring 3, an amorphous Si layer 5, an n ⁺ type amorphous S serving as a source electrode 6 and a drain electrode 7 are formed.
An i-layer is sequentially formed and patterned into the illustrated shape.

Subsequently, as shown in FIG. 2C,
Forming an ITO film to be the source signal line 8 and the connection electrode 9;
It is patterned into a predetermined shape. At this time, the ITO
By etching the channel region 21 when patterning the n ⁺ -type amorphous Si layer, the n ⁺ -type amorphous Si layer is divided into a source electrode 6 and a drain electrode 7. Although not shown, an upper part of the amorphous Si layer 5
An etching stopper may be formed to prevent the n ⁺ -type amorphous Si layer formed thereon from being damaged during etching.

Subsequently, as shown in FIG.
After a channel protective film 10 for protecting the channel region 21 of the amorphous Si layer 5 is formed on the entire surface of the substrate, a metal film to be a light shielding film 11 is subsequently formed, and the channel protective film 10 and the light shielding film are formed by photolithography. 11 is patterned into a shape shown by hatching in FIG. In this patterning, the light shielding film 11 and the channel protective film 10 may be simultaneously etched by a dry etching method, or the light shielding film 11 may be etched by a dry etching method, and then the channel protective film 1 may be etched.
0 may be etched by a wet etching method. In any case, since the light-shielding film 11 and the channel protective film 10 can be formed by one pattern formation using a photoresist, the process can be shortened. The light-shielding film 11 may be made of black resin or the like in addition to metal.

Subsequently, as shown in FIG.
After an interlayer insulating film 12 made of a photosensitive acrylic resin is formed by a spin coating method and a contact hole 14 is formed, ITO serving as a pixel electrode 13 is formed by a sputtering method and patterned into a predetermined shape. In addition,
The contact hole 14 can be formed by exposing the acrylic resin according to a predetermined pattern and treating it with an alkaline solution.

The TFT substrate thus formed and a color filter substrate on which a not-shown counter electrode and a color filter are formed are bonded together with a predetermined gap therebetween, and a liquid crystal is sealed in the gap. The liquid crystal display device is completed by combining the lighting device with the lighting device.

In this liquid crystal display device, since a light-shielding film for shielding light between pixel electrodes and a channel region of the TFT is formed on the TFT substrate, it is not necessary to form a light-shielding film on the color filter substrate. It can be formed at low cost.

Also, in the case of a TFT substrate, it has conventionally been necessary to form a source signal line in two layers of a transparent conductive film and a metal layer and pattern these in separate steps. Since the light shielding film 11 covering the
The source signal line 8 can be formed with one layer of the transparent conductive film, and the manufacturing process can be simplified. In addition, since the metal to be formed as the light-shielding film 11 is simultaneously formed in the same shape as the channel protective film 10, the manufacturing process can be simplified.

[0029]

As described above, according to the first aspect of the present invention,
According to the liquid crystal display device described above, since the light-shielding film is provided on the source signal line and the switching element and below the interlayer insulating film, it is not necessary to form the light-shielding film on the color filter substrate. Therefore, the color filter substrate can be formed at a low cost, and the adjacent pixel electrodes do not leak due to patterning misalignment as compared with the case of forming a light-shielding film on the pixel electrodes as in the prior art, thereby improving reliability. There is an effect that it can be improved.

According to the liquid crystal display device of the present invention, in the case where a thin film transistor is used as the switching element and a channel protective film is formed in a region including immediately above a channel region of the thin film transistor, the channel protective film is formed. By patterning the light-shielding film and the light-shielding film into the same shape, there is an effect that the light-shielding film can be formed on the TFT substrate without greatly increasing the manufacturing process.

Further, by forming the light-shielding film also on the source signal line, the source signal line can be formed only of the transparent conductive film, and the production process can be shortened.

According to the method of manufacturing a liquid crystal display device of the present invention, a step of sequentially forming a gate signal line, a gate insulating film, a switching element, and a source signal line on a substrate; Forming a protective film and a light-shielding film successively, and patterning using the same resist pattern,
As compared with the conventional case in which the protective film and the light-shielding film are formed in separate steps, an effect is obtained that the manufacturing process can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view showing a TFT substrate of a liquid crystal display device according to the present invention.

FIG. 2 is a flowchart showing a process of manufacturing a TFT substrate of a liquid crystal display device according to the present invention.

FIG. 3 is a plan view and a cross-sectional view illustrating a TFT substrate of a liquid crystal display device according to the related art.

FIG. 4 is a plan view and a cross-sectional view showing a TFT substrate of a liquid crystal display device according to the related art.

FIG. 5 is a plan view and a cross-sectional view illustrating a TFT substrate of a liquid crystal display device according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Translucent substrate 2 Gate electrode 3 Capacitance wiring 4 Gate insulating film 5 Amorphous Si layer 6 Source electrode 7 Drain electrode 8 Source signal line 9 Connecting electrode 10 Channel protective film 11 Light shielding film 12 Interlayer insulating film 13 Pixel electrode 14 Contact hole 15 TFT 20 Gate signal line 21 Channel region

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 21/336 H01L 29/78 619B

Claims (4)

[Claims] An interlayer insulating film having a plurality of gate signal lines, source signal lines, and matrix-like switching elements orthogonal to each other, and having a contact hole covering the gate signal lines, the source signal lines, and the switching elements. A liquid crystal display device, comprising: a pixel electrode connected to the switching element via the contact hole on the interlayer insulating film; and on the source signal line and the switching element,
A liquid crystal display device, wherein a light-shielding film is provided below the interlayer insulating film. 2. The switching element is a thin film transistor, a channel protection film is formed in a region including immediately above a channel region of the thin film transistor, and the channel protection film and the light shielding film are patterned into the same shape. The liquid crystal display device according to claim 1, wherein 3. The liquid crystal display device according to claim 2, wherein said source signal line is formed only of a transparent conductive film. 4. A gate signal line, a gate insulating film,
A step of sequentially forming a switching element and a source signal line; and a step of continuously forming a protective film and a light-shielding film on the switching element and patterning the same using the same resist pattern. Of manufacturing a liquid crystal display device.