JPH09152626A - Liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify production stages, to reduce a manufacturing cost, and to improve the yield of production by constituting the surface layers of scanning signal wirings of aluminum alloys added with high melting metals or the specific high melting metals. SOLUTION: A transparent glass substrate 13 is provided thereon with image signal wirings 2 and the section signal wirings 1, 1' via insulating films 8, 8' so as to intersect with each other. Pixel electrodes 3 and thin-film transistors(TFTs) 5 of an inverted stagger type for supplying image signals to these pixel electrodes 3 are disposed in a matrix form at the intersected points of the image signal wirings 2 and the scanning signal wirings 1, 1'. The scanning wirings 1 are composed of the high melting metals, such as tungsten (W), molybdenum (Mo), titanium (Ti), nickel (Ni) and chromium (Cr), having oxide forming energy of >=-300kcal or thier alloys, or the alloys composed of the high melting metals, such as tungsten (W), molybdenum (Mo), tantalum (Ta), nickel (Ni) and chromium (Cr), and aluminum.

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 device and a manufacturing method thereof, and more particularly to an active matrix type liquid crystal display device having a switching thin film transistor in each pixel portion and an improvement in the manufacturing method thereof.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device includes a pixel electrode and a switching thin film transistor (TF).
T) is mainly formed on the TFT array substrate and the counter electrode substrate on which the counter electrode is formed.

The structure of a conventional TFT array substrate will be described with reference to FIGS. FIG. 8 is a diagram showing an electrical configuration of a conventional TFT array substrate, FIG. 9 is a diagram showing a state where one pixel portion is viewed in plan, and FIG. 10 is a sectional view taken along the line AA ′ of FIG. 9 including a counter electrode substrate. FIG. 11 is a sectional view taken along the line BB ′ of FIG. 9 including the counter electrode substrate.

8 to 11, 31 is a scanning signal wiring, 32 is an image signal wiring, 33 is a pixel electrode, 35 is a thin film transistor, 37 is a black matrix, 38 is an insulating film, 39 is a protective film, and 40 is a liquid crystal material. , 41 are counter electrodes, and 42, 43 are transparent glass substrates.

A plurality of scanning signal wirings 31 and a plurality of image signal wirings 32 are provided on a transparent glass substrate 43 so as to intersect each other with an insulating film 38 interposed therebetween. Each of the scanning signal wirings 31 and the image signal wirings 32 is provided. At the intersection, the pixel electrode 33 and this pixel electrode 33
Stagger type thin film transistor 3 for supplying image signal to
And 5 are provided in a matrix. The thin film transistor 35 includes a gate electrode G formed so as to project from the scanning signal line 31, a gate insulating film formed of an insulating film 38,
It is composed of a high resistance semiconductor film 36 which becomes a channel region, a low resistance semiconductor film 44 which becomes an ohmic contact layer, a source electrode S and a drain electrode D. This source electrode S
Is formed so as to project from the image signal wiring 32, and the drain electrode D is formed so as to be connected to the pixel electrode 33.

A TFT is formed on the transparent glass substrate 42.
A black matrix 37 and a counter electrode 41 for preventing light leakage from between the pixel electrodes 33 of the array substrate are provided. An image display is performed by sandwiching the liquid crystal material 40 between the pixel electrode 33 and the counter electrode 41 and selectively supplying an image signal to the pixel electrode 33 via the thin film transistor 35.
That is, ON / OFF of the thin film transistor 35 is controlled by the scanning signal supplied from the scanning signal wiring 31, and the image signal supplied from the image signal wiring 32 is supplied to the pixel electrode 33 via the source electrode S and the drain electrode D. To be done.

As shown in FIG. 8, the scanning signal wiring 3
One end of 1 is connected to the short-circuit ring wiring 49 via the wiring 46, and one end of the image signal wiring 32 is connected to the short-circuit ring wiring 49 via the high-voltage protection thin film transistors 51 and 52. The short-circuit ring wiring 49 is provided in order to prevent the insulating film 38 from being electrostatically destroyed in the manufacturing process, and the high voltage protection thin film transistor 51 has each image signal wiring 32 with a predetermined value or more. The connection is provided through a resistor so that the image signal wirings 32 can be inspected for short circuit or disconnection.

A method of manufacturing the TFT array substrate having the above structure will be described with reference to FIGS. FIG. 12 shows a manufacturing process of the pixel electrode portion, FIG. 13 shows a manufacturing process around the lead terminal of the scanning signal wiring 31, and FIG.
Shows a manufacturing process around the lead terminal of the image signal wiring 32.

12 to 14, 34 is an etching stopper film, 35 is a thin film transistor, 38 is an insulating film, 39 is a protective film, 43 is a transparent glass substrate, 44 is a low resistance semiconductor film of the thin film transistor 35, and 49 is a short-circuit ring. Wiring, 50 is an external lead terminal of the image signal wiring, 51 is a thin film transistor for high voltage protection, 52 is a gate electrode of the thin film transistor for high voltage protection 51, and 53 is an electrode junction of the thin film transistor for high voltage protection.

First, the manufacturing process of the pixel electrode 33 portion is shown in FIG.
2 will be described. As shown in FIG. 3A, an electrode 3 also serving as a scanning signal wiring such as tantalum (Ta) and a gate electrode of the thin film transistor 35 is formed on a glass substrate 43.
1, 31 'are selectively formed.

Next, as shown in FIG. 1B, an insulating film 38 of silicon nitride or the like is formed, and a high resistance semiconductor film 36 of amorphous silicon or the like and an etching stopper film 34 of silicon nitride or the like are formed. After that, the high resistance semiconductor film 3
6 and the etching stopper film 34 are selectively etched simultaneously.

Next, as shown in FIG. 3C, the etching stopper film 34 is patterned so as to have a smaller area.

Next, as shown in FIG. 3D, a low resistance semiconductor film 4 such as an amorphous silicon film to which impurities are added.
4 is formed and selectively etched.

Next, as shown in FIG. 3E, the pixel electrode 33 made of a transparent conductive film (ITO) or the like is selectively formed.

Next, as shown in FIG. 3F, a metal film of chromium (Cr) or the like is formed and patterned to form the source / drain of the image signal wiring 32 and the thin film transistor 35.
The drain electrode (S) and the drain electrode (D) are formed.

Finally, as shown in FIG. 3G, an insulating protective film 39 made of silicon nitride or the like is formed and patterned to form the protective film 39 on the portion excluding the pixel electrodes 33. To do.

Next, the manufacturing process around the lead terminal of the scanning signal wiring 31 will be described with reference to FIG.

First, as shown in FIG. 13A, the end portion of the scanning signal wiring 31 is formed. This is the same process as FIG.

Next, as shown in FIG. 13B, the insulating film 38 is formed. This is the same process as that of FIG.

Next, as shown in FIG. 13C, a part of the insulating film 38 is etched to expose a part of the scanning signal wiring 31. This process is shown in FIGS. 12 (d) and 12 (e).
During the process of.

Next, as shown in FIG. 13D, the wiring 46 is formed on the scanning signal wiring 31 with a transparent conductive film (ITO) or the like. The wiring 46 is formed at the same time as the pixel electrode 33 shown in FIG.

Next, as shown in FIG. 13E, the wiring 4
The short-circuit ring wiring 49 is formed on the surface 6 by a metal film such as chromium (Cr). The short circuit ring wiring 49 is formed simultaneously with the image signal wiring 32 of FIG.

Finally, the protective film 39 is formed and the wiring 46 is formed.
A part of the protective film 39 is removed by etching so that the film is exposed. The formation and etching of the protective film 39 is performed as shown in FIG.
This is performed simultaneously with the step shown in (g). In this way,
The exposed external lead terminal 47 is formed.

Next, the manufacturing process around the lead terminal of the image signal wiring 32 will be described with reference to FIG.

First, as shown in FIG. 14A, the gate electrode 52 of the high voltage protection thin film transistor 51 is shown in FIG.
It is formed at the same time as the scanning signal wiring 31 shown in FIG.

Next, as shown in FIG. 14B, after forming the high resistance semiconductor film 36 and the etching stopper film 34 of the high voltage protection thin film transistor 51, the high resistance semiconductor film 36 and the etching stopper film 34 are formed. At the same time, selective etching is performed. This step is the same as the step shown in FIG.

Next, as shown in FIG. 14C, the etching stopper film 34 is etched into a small area simultaneously with the step shown in FIG. 12C.

Next, as shown in FIG. 14D, the low resistance semiconductor film 44 of the high voltage protection thin film transistor 51 is
It is selectively formed simultaneously with the step of FIG.

Next, as shown in FIG. 14E, part of the insulating film 38 is etched to expose part of the gate electrode 52. This step is performed between the steps of FIGS. 12D and 12E, and is performed at the same time as the step of FIG. 13C.

Next, as shown in FIG. 14F, the source electrode (S) and the drain electrode (D) of the high voltage protection thin film transistor 51 are formed. This process is shown in FIG.
It is performed simultaneously with the step (f). The source electrode (S) and the gate electrode (G) of the high voltage protection thin film transistor 51 are formed by short-circuiting via the wiring 32.

Next, as shown in FIG. 14G, a protective film 39 is formed on the high voltage protection thin film transistor 51 to complete the process. This protective film 39 is the protective film 3 of FIG.
It is formed at the same time as 9 and patterned.

[0032]

However, in the above-mentioned conventional liquid crystal display device, since the thin film transistor 35 is a thin film transistor provided with the etching stopper film 34, a step for patterning the etching stopper film 34 (FIG. 12). (C)) is specially required, and the step of forming and patterning the low resistance semiconductor film 44 (FIG. 12D) is also specially required, and ITO is formed on the terminal portion of the scanning signal wiring 31. Since the gate electrode G and the source electrode S of the high voltage protection thin film transistor 51 are directly connected to each other while forming a transparent conductive film such as the above, the terminal portion of the scanning signal line 31 and the gate electrode portion 52 of the high voltage protection thin film transistor 51 are connected. Special step for forming a contact hole in the insulating film 38 in FIG.
14 (e)) and that the pixel electrode 33 made of a transparent conductive film such as ITO is formed before the image signal wiring 32, the source electrode S and the drain electrode D of the thin film transistor 35 are formed. , A special step for forming the source electrode S and the drain electrode D of the image signal wiring 32 and the thin film transistor 35 (FIG. 12).
(F)) is required, the manufacturing process is complicated, the manufacturing cost increases, and the manufacturing yield decreases. That is, in the manufacturing process of the TFT array substrate in the conventional liquid crystal display device, a photomask is required in each step of FIGS. 12A to 12G and the step of FIG. 13C (FIG. 14E). However, there is a problem that a total of eight photolithography processes are required.

The present invention has been invented in view of the above problems of the prior art, and solves the complexity of the manufacturing process by a large number of photolithography processes, the increase of the manufacturing cost, and the reduction of the manufacturing yield. The purpose is to do.

[0034]

In order to achieve the above object, in a liquid crystal display device according to claim 1, a plurality of image signal wirings and a plurality of scanning signal wirings are crossed with an insulating film interposed therebetween. Pixel electrodes and inverted staggered thin film transistors that supply image signals to the pixel electrodes are provided in a matrix at the intersections of the image signal lines and the scanning signal lines, and the pixel electrodes and the pixel electrodes are provided so as to face the pixel electrodes. In a liquid crystal display device in which a liquid crystal material is held between the counter electrode and the counter electrode, the thin film transistor is a channel etch type,
An insulating protective film is formed so as to cover the thin film transistor and the image signal wiring, in the lead terminal portion of the image signal wiring, a part of the image signal wiring is exposed, and in the lead terminal portion of the scanning signal wiring, Part of the scanning signal wiring is exposed, and the surface layer of the scanning signal wiring is made of an aluminum alloy added with a refractory metal or a refractory metal having an oxide formation energy of -300 kcal or more.

In the method of manufacturing a liquid crystal display device according to claim 7, an aluminum alloy containing a refractory metal or a refractory metal having an oxide formation energy of -300 kcal or more is provided on the surface layer of the scanning signal wiring. The scanning signal wiring and the image signal wiring are provided so as to intersect with each other through an insulating film, and a pixel electrode at the intersection of the scanning signal wiring and the image signal wiring and a channel-etch type inverted stagger for supplying an image signal to the pixel electrode. Type thin film transistors are provided in a matrix, an insulating protective film is formed so as to cover the thin film transistors and the image signal wiring, and a liquid crystal is provided between the pixel electrode and a counter electrode provided to face the pixel electrode. In a method of manufacturing a liquid crystal display device in which a material is injected, patterning of the protective film on the pixel electrode and forming of a front terminal on a lead terminal of the image signal wiring are performed. And performing the patterning of the protective film and the insulating film of the lead terminal portion of the patterning and the scanning signal lines of the protective film at the same time.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid crystal display device and a manufacturing method thereof according to the present invention will be described below in detail with reference to the accompanying drawings.

1 to 4 are views showing an embodiment of the liquid crystal display device according to claim 1, FIG. 1 is a view showing an electrical configuration of a TFT array substrate, and FIG. 2 is a plan view of the TFT array substrate. It is a figure which shows the state which looked at, FIG. 3 is the sectional view on the AA 'line of FIG. 2 including a counter electrode substrate, and FIG. 4 is the sectional view on the BB' line of FIG. 2 also including a counter electrode substrate. . 1 to 4, 1 is a scanning signal wiring, 2 is an image signal wiring,
3 is a pixel electrode, 4 is a band-shaped light-shielding electrode, 5 is a thin film transistor, 6 is a high resistance semiconductor film, 7 is a black matrix,
8 is a gate insulating film, 9 is a protective film, 10 is a liquid crystal material, 11
Is a counter electrode, and 12 and 13 are transparent glass substrates.

On the transparent glass substrate 13, a plurality of image signal wirings 2 and 2'and a plurality of scanning signal wirings 1 and 1'are provided so as to intersect with each other through insulating films 8 and 8 '. Pixel electrodes 3 and inversely staggered thin film transistors 5 for supplying image signals to the pixel electrodes 3 are provided in a matrix at each intersection of 2, 2'and the scanning signal wirings 1, 1 '.

The scanning signal wiring 1 is made of a refractory metal such as tungsten (W), molybdenum (Mo), titanium (Ti), nickel (Ni), and chromium (Cr) having an oxide formation energy of -300 kcal or more, or a refractory metal thereof. An alloy or an alloy of aluminum with a refractory metal such as tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), nickel (Ni), or chromium (Cr) is used. When the scanning signal wiring 1 is formed of a laminated film, at least the uppermost layer may be formed of the refractory metal or the alloy of the refractory metal and aluminum as described above.

The insulating film 8 is made of, for example, a silicon oxide film, and the insulating film 8'is made of, for example, a silicon nitride film.

The image signal wirings 2 and 2'include a high-resistance semiconductor film 6 such as amorphous silicon containing no semiconductor impurities or only a small amount thereof, a low-resistance semiconductor film 14 containing semiconductor impurities at a high concentration, and a barrier metal film. 15 and transparent conductive film 3 such as ITO. The barrier metal film 15 includes tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), nickel (Ni),
It is made of a refractory metal such as chromium (Cr) or an alloy of these refractory metals and aluminum.

The pixel electrode 3 is formed of a transparent conductive film such as ITO.

The thin film transistor 5 is composed of the scanning signal line 1,
A gate electrode G, an insulating film 8 formed so as to project from 1 ',
8 ′, a gate insulating film, a high resistance semiconductor film 6 to be a channel region, a low resistance semiconductor film 14 to be a source electrode S and a drain electrode D, a barrier metal film 15 and a transparent conductive film 3. This thin film transistor 5 is
It is composed of a channel-etch type thin film transistor in which an etching stopper film is not formed in the channel portion.

The high-resistance semiconductor film 6 which becomes the channel region of the thin film transistor is preferably formed of a lower semiconductor layer containing no nitrogen element and carbon element and an upper semiconductor layer containing nitrogen element or carbon element. When the high-resistance semiconductor film 6 which becomes the channel region of the thin film transistor is formed by the lower semiconductor layer containing no nitrogen element and carbon element and the upper semiconductor layer containing nitrogen element or carbon element as described above, good characteristics are maintained. The high-resistance semiconductor film 6 and the low-resistance semiconductor film 14 can be selectively etched, and the thickness of the high-resistance semiconductor film 6 which was conventionally required to be 2500 to 3000 Å can be reduced to about 500 to 1000 Å, and image signal wiring can be achieved. The thickness of 2 and 2'can also be reduced, and the manufacturing yield is improved.

Further, on the transparent glass substrate 12, a black matrix 7 and a counter electrode 11 for preventing light leakage from a gap between adjacent pixel electrodes 3 are provided.

On the transparent glass substrate 13 between the image signal wiring 2 and the pixel electrode 3, band-shaped light shielding electrodes 4 and 4'are provided. The strip-shaped light-shielding electrodes 4 and 4 ′ are formed in a layer at the same level as the scanning signal wiring 1. Therefore, light leakage is prevented from occurring between the pixel electrode 3 and the image signal wiring 6 as much as possible, the black matrix 7 on the counter electrode substrate 12 side can be formed in a narrow width, and the aperture ratio of the pixel electrode 3 portion is improved. Can be made.

The liquid crystal material 10 is composed of the pixel electrode 3 and the counter electrode 11.
An image display is performed by sandwiching and sandwiching, and selectively supplying an image signal to the pixel electrode 3 by the thin film transistor 5. That is, the thin film transistor 5 is turned on by the scanning signal supplied from the scanning signal wiring 1, and the image signal supplied from the image signal wiring 2 is supplied to the pixel electrode 3 via the source electrode S and the drain electrode D.

As shown in FIG. 1, a first short-circuit ring wiring 27a and a second short-circuit ring wiring 19 are provided on the outer peripheral portion of the display area X. Each scanning signal wiring 1 is connected to the first short-circuit ring wiring 27 a, and each image signal wiring 2 is connected to the second short-circuit ring wiring 19 via the high-voltage protection transistor 21.

Next, the TFT of the liquid crystal display device according to the present invention
A method of manufacturing the array substrate side will be described with reference to FIGS. 5, 6 and 7. 5, 6 and 7, 1 is a scanning signal wiring, 2 is an image signal wiring, 3 is a pixel electrode, 4 is a band-shaped light shielding electrode, 5 is a thin film transistor, 6 is a high resistance semiconductor film, and 8 and 8 ′ are Insulating film, 9 protective film, 10 liquid crystal material, 13 transparent glass substrate, 14 low resistance semiconductor film, 1
Reference numeral 5 is a barrier metal film, 17 is an external lead terminal of the scanning signal wiring, 18 is a discharge type connection portion, 19 is a short-circuit ring wiring, 20
Is an external lead-out terminal of the image signal wiring, 21 is a capacitive coupling type high voltage protection thin film transistor, 22 is a gate electrode of the high voltage protection thin film transistor, and 23 is a gate capacitance connection portion of the high voltage protection thin film transistor 21.

FIG. 5 is a diagram showing a manufacturing process of a pixel portion on the TFT array substrate. First, as shown in FIG. 3A, an aluminum alloy added with a refractory metal or a refractory metal having an oxide formation energy of −300 kcal or less is formed on the glass substrate 1 by a sputtering method or the like and patterned. Thus, the wirings 1 and 1 ′ which also serve as the scanning signal wiring and the gate electrode of the thin film transistor 5 are selectively formed. The strip-shaped light-shielding electrodes 4 and 4'shown in FIG. 3 are also formed simultaneously with the scanning signal wirings 1 and 1 '.

Next, as shown in FIG. 9B, the insulating films 8 and 8'having a two-layer structure, the high resistance semiconductor film 6 and the low resistance semiconductor film 14 are successively formed by a plasma CVD method or the like. After that, a barrier metal 15 made of a refractory metal or an alloy thereof is continuously formed by a sputtering method or the like, and the barrier metal 15, the low resistance semiconductor film 14 and the high resistance semiconductor film 6 are selectively selected at the same time by the same photomask. To etch. In the present invention, since a channel-etch type thin film transistor is formed, a layer to be a source / drain electrode can be formed continuously to a layer to be a channel of the transistor.

Next, as shown in FIG. 6C, a transparent conductive film made of ITO or the like is formed by a sputtering method or the like,
Transparent conductive film 3, barrier metal 15, low resistance semiconductor film 14
Are selectively etched with the same photomask, so that the pixel electrode 3, the high resistance semiconductor film 6, the low resistance semiconductor film 14, the barrier metal 15, and the image signal wiring 2 including the transparent conductive film 3 and the switching transistor 5 are formed. Form.

Finally, as shown in FIG. 3D, a protective film 9 made of a silicon nitride film or the like is formed by a plasma CVD method or the like and patterned to remove the protective film 9 on the pixel electrode 3. Then, the TFT array substrate is completed.

FIG. 6 is a diagram showing a manufacturing process around the scanning signal wiring lead-out terminal portion in the TFT array substrate of the present invention.

First, as shown in FIG. 6A, the substrate 13
An end portion of the scanning signal wiring 1 is formed on the top. This step is the same as the step shown in FIG.

Next, as shown in FIG. 6B, the insulating films 8 and 8'having a two-layer structure are formed, and the high resistance semiconductor film 6, the low resistance semiconductor film 14 and the barrier metal 1 are formed.
5 islands are formed. This step is shown in FIG.
It is the same as the process shown in FIG.

Next, as shown in FIG. 6C, the transparent conductive film 16 made of ITO or the like is formed on the island-shaped portion, and the transparent conductive film 16 is left so as to partially overlap the scanning signal wiring. Are removed by etching. This step is the same as the step of forming the pixel electrode 3 shown in FIG.

Next, as shown in FIG. 6D, a protective film 9 made of a silicon nitride film or the like is formed, and a predetermined portion is removed by etching to complete the processing around the lead terminal portion of the scanning signal wiring 1. To do. This step is the same as the step shown in FIG. When the periphery of the lead-out terminal portion of the scanning signal wiring 1 is formed as described above, the discharge type connection portion 18 is formed. Therefore, when the voltage of the wiring 16 and the voltage of the wiring 1 are significantly different, the exposed portion of the wiring 16 and the wiring It is prevented that electric discharge occurs in the exposed portion of 1 and the insulating films 8 and 8 ′ are destroyed. In the present invention, the scanning signal wiring 1 has an energy of forming an aluminum alloy or oxide containing a refractory metal of −3.
Since it is formed of a refractory metal of 001 cal or higher,
Even at the end portion 17 of the scanning signal wiring 1, the scanning signal wiring 1 can be connected to an external circuit without being covered with an oxide conductive film such as ITO. That is, in a liquid crystal display device or the like, an external circuit (driving IC, etc.)
It has been proposed to connect the drive IC to the terminal portion by the micro bump bonding method in order to easily connect the drive IC to the terminal portion. Driving IC in the micro bump bonding method
Since the pad and the terminal portion of the signal wiring are brought into contact with each other without being bonded to each other, they are conventionally formed of ITO or the like that exhibits conductivity even when an oxide is formed. When a high melting point metal having an oxide formation energy of −300 kcal or more is formed, the surface of the scanning signal wiring 1 is hardly oxidized, and when formed with an alloy of a high melting point metal and aluminum, an oxide film is formed. Even if it is formed, it can be easily pierced by the pad portion of the driving IC, etc. Therefore, it is practical even if the terminal portion of the scanning signal wiring 1 is not covered with the oxide conductive film of ITO. Further, the same effect can be expected in the conventional connection method using the anisotropic conductive film. As a result, the step of forming a contact hole or the like for connecting the scanning signal line 1 and the oxide conductive film 16 can be omitted. Further, since the protective film 9 and the insulating films 8 and 8'are removed at the same time, they can be removed in one step.

FIG. 7 shows a TFT of the liquid crystal display device according to the present invention.
It is a figure which shows the manufacturing process of the drawing terminal part periphery of the image signal wiring 2 in an array substrate.

First, as shown in FIG. 7A, the gate electrode 22 of the high voltage protection transistor 21 is formed. This gate electrode 22 is the same as the step of FIG.

Next, as shown in FIG. 7B, the insulating films 8 and 8'having a two-layer structure are formed, and the high resistance semiconductor film 6, the low resistance semiconductor film 14 and the barrier metal film 15 are formed. Then, the end portions of the high resistance semiconductor film 6, the low resistance semiconductor film 14 and the barrier metal film 15 are removed by etching. This step is the same as the step shown in FIG.

Next, as shown in FIG. 7C, the transparent conductive film 16 is formed, and the transparent conductive film 1 on the gate electrode 22 is formed.
6, part of the barrier metal film 15 and the low resistance semiconductor film 14 is removed. This step is the same as the step shown in FIG.

Next, a protective film 9 made of a silicon nitride film or the like is formed, and a part thereof is removed to form an external lead terminal 20 of the image signal wiring 2, and at the same time, for capacitive coupling type high voltage protection. The thin film transistor 21 is formed. That is, the transistor 21 is formed by the gate electrode 21, the insulating films 8 and 8 ′, the semiconductor film 6, the source electrode S, and the drain electrode D. In this case, the gate electrode G and the source electrode S are capacitively coupled.

Therefore, the source electrode S and the gate electrode G
It is not necessary to form a contact hole for connecting the insulating films 8 and 8 '.

As described above, in the TFT array substrate of the liquid crystal display device according to the present invention, the pixel electrode 3 portion, the scanning signal wiring 1 terminal portion, and the high voltage protection transistor 21 portion are all subjected to four photolithography steps. Can be formed.

In the above embodiment, when the scanning signal wiring 1 and the short circuit wiring 16 are connected, they can be connected by discharge. However, in the process shown in FIG. 6A, the end portion of the scanning signal wiring 1 is It is left without being removed, a mask is provided on the end portion, and the insulating films 8 and 8 ′, the low resistance semiconductor film 6, the high resistance semiconductor film 14 and the barrier metal film 15 of FIG. 3B are formed. The mask is removed on the transparent conductive film 16
May be formed. Thus, by using the mask, the scanning signal wiring 1 and the short-circuit wiring 16 can be directly connected without complicating the process.

[0067]

As described above, according to the liquid crystal display device of the present invention, the thin film transistor is a channel etch type, and the insulating protective film is formed so as to cover the thin film transistor and the image signal wiring, and the image signal is formed. A part of the image signal wiring is exposed at the lead terminal portion of the wiring, a part of the scan signal wiring is exposed at the lead terminal portion of the scanning signal wiring, and a refractory metal is added to the surface layer of the scan signal wiring. Since the aluminum alloy or the refractory metal having an oxide formation energy of -300 kcal or more is used, the photolithography process is reduced to four times, the manufacturing process is simplified, the manufacturing cost is reduced, and the manufacturing yield is improved.

Further, according to the method of manufacturing a liquid crystal display device of the present invention, the energy for forming an aluminum alloy or oxide in which a refractory metal is added to the surface layer of the scanning signal wiring is −.
A refractory metal of 300 kcal or more is provided, and the scanning signal wiring and the image signal wiring are provided so as to intersect with each other with an insulating film interposed therebetween.
Pixel electrodes and channel-etched and inverted staggered thin film transistors that supply image signals to the pixel electrodes are provided in a matrix at the intersections of the scanning signal lines and the image signal lines to cover the thin film transistors and the image signal lines. A method for manufacturing a liquid crystal display device, wherein an insulating protective film is formed on the pixel electrode, and a liquid crystal material is injected between the pixel electrode and a counter electrode provided so as to face the pixel electrode. And the patterning of the protective film on the lead-out terminal of the image signal wiring and the patterning of the protective film and the insulating film on the lead-out terminal portion of the scanning signal wiring are performed at the same time. Therefore, the manufacturing process is simplified, the manufacturing cost is reduced, and the manufacturing yield is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a TFT array substrate of a liquid crystal display device according to the present invention.

FIG. 2 is an enlarged view of one pixel of the liquid crystal display device according to the present invention.

3 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 4 is a sectional view taken along line B-B ′ of FIG.

FIG. 5 is a cross-sectional view in the manufacturing process order of the pixel portion.

FIG. 6 is a process cross-sectional view around a lead terminal of a scanning signal wiring.

FIG. 7 is a process cross-sectional view around a lead terminal of an image signal wiring.

FIG. 8 is a diagram showing a TFT array substrate of a conventional liquid crystal display device.

FIG. 9 is an enlarged view of one pixel of a conventional liquid crystal display device.

10 is a cross-sectional view taken along the line A-A ′ of FIG.

11 is a sectional view taken along line B-B ′ of FIG.

FIG. 12 is a cross-sectional view in order of the manufacturing steps of the pixel section.

FIG. 13 is a process sectional view around a lead terminal of a scanning signal wiring.

FIG. 14 is a process cross-sectional view around a lead terminal of an image signal wiring.

[Explanation of symbols]

1, 31 ... Scan signal wiring, 2, 32 ... Image signal wiring, 3, 33 ... Pixel electrode, 4 ... Band-shaped light shielding electrode, 5, 35 ... Thin film transistor, 6, 36 ...・ ・
High resistance semiconductor film, 7, 37 ... Black matrix,
8, 38 ... Gate insulating film, 9, 39 ... Protective film,
10, 40 ... Liquid crystal material, 11, 41 ... Counter electrode, 12, 13, 42, 43 ... Transparent glass substrate, 1
4, 44 ... Low resistance semiconductor film, 15 ... Barrier metal film, 16 ... Transparent conductive film, 17, 47 ... External lead-out terminal of scan signal wiring, 18 ... Discharge type connection part,
19, 49 ... Short circuit ring wiring, 20, 50 ... External lead-out terminal of image signal wiring, 21 ... Capacitively coupled high-voltage protection thin film transistor, 22 ... High-voltage protection thin film transistor 21 gate Electrodes, 23 ... Gate capacitance connection part of high voltage protection thin film transistor 21, 34
... Etching stopper film, 45 ... Metal film, 5
1 ... High voltage protection thin film transistor, 52 ... High voltage protection thin film transistor 51 gate electrode, 53 ...
..Electrode junction of thin film transistor for high voltage protection

Claims (10)

[Claims] 1. A plurality of image signal wirings and a plurality of scanning signal wirings are provided so as to intersect with each other through an insulating film, and a pixel electrode is provided at an intersection of the image signal wiring and the scanning signal wiring and an image signal is provided to the pixel electrode. In a liquid crystal display device in which a reverse stagger type thin film transistor for supplying a liquid crystal is provided in a matrix, and a liquid crystal material is held between the pixel electrode and a counter electrode provided so as to face the pixel electrode, the thin film transistor is It is a channel etch type, an insulating protective film is formed so as to cover the thin film transistor and the image signal wiring, and a part of the image signal wiring is exposed at the lead-out terminal portion of the image signal wiring. In the lead-out terminal portion of, the scanning signal wiring is partially exposed, and the surface layer of the scanning signal wiring is an aluminum alloy or an oxide containing a refractory metal. Material formation energy is -300kca
A liquid crystal display device comprising a refractory metal of 1 or more. 2. The image signal wiring comprises a laminated film of a high resistance semiconductor film, a low resistance semiconductor film, a barrier metal film and a transparent conductive film, and in the channel portion of the thin film transistor,
The liquid crystal display device according to claim 1, wherein the transparent conductive film, the barrier metal film, and the low-resistance semiconductor film are patterned into substantially the same shape. 3. A lower semiconductor layer in which the semiconductor curtain of the thin film transistor is composed of a high resistance semiconductor film serving as a channel layer and a low resistance semiconductor film serving as an ohmic contact layer, and the high resistance semiconductor film does not contain nitrogen element and carbon element. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal display device comprises an upper semiconductor layer containing a nitrogen element or a carbon element. 4. A short-circuit wiring, in which the plurality of image signal wirings are connected via a transistor, is provided in an outer peripheral portion of the display area, and a gate electrode and a source electrode or a drain electrode of the transistor are provided via the insulating film. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is capacitively coupled. 5. A plurality of scanning signal wirings and a short-circuit ring wiring for discharging static electricity of the plurality of scanning signal wirings are stacked and provided in the outer peripheral portion of the display area through the insulating film, and the stacked wirings are stacked. The liquid crystal display device according to claim 2, wherein the protective film and the insulating film are removed in a portion to expose a part of the short-circuit ring wiring and the scanning signal wiring. 6. A strip-shaped member which is formed on the back surface side of the pixel electrode through the insulating film and extends toward the image signal wiring side with respect to the pixel electrode, and is separated for each pixel made of the same material as the scanning signal wiring. The liquid crystal display device according to claim 2, further comprising a light-shielding electrode. 7. A scan signal wiring is provided with a refractory metal having a melting point of −300 kcal or more of an aluminum alloy added with a refractory metal or an oxide forming energy, and the scan signal wiring and the image signal wiring are provided with an insulating film interposed therebetween. Are provided so as to intersect with each other, and pixel electrodes and channel-etch type reverse stagger type thin film transistors for supplying image signals to the pixel electrodes are provided in a matrix at intersections of the scanning signal lines and the image signal lines, and the thin film transistors and the thin film transistors are provided. An insulating protective film is formed to cover the image signal wiring, and a liquid crystal material is injected between the pixel electrode and a counter electrode provided so as to face the pixel electrode. Patterning of the protective film on the electrode, patterning of the protective film on the lead terminal of the image signal wiring, and lead-out end of the scanning signal wiring A method of manufacturing a liquid crystal display device, wherein the patterning of the protective film and the insulating film of the child portion is performed at the same time. 8. The image signal wiring is formed of a laminated film of a high resistance semiconductor film, a low resistance semiconductor film, a barrier metal film and a transparent conductive film, and the low resistance semiconductor film and the barrier are formed in a channel portion of the thin film transistor. The method for manufacturing a liquid crystal display device according to claim 6, wherein the metal film and the transparent conductive film are patterned by the same photomask. 9. The insulating film is formed of a laminated film of a first insulating film and a second insulating film, and after forming the first insulating film, the second insulating film and the high resistance film are formed. The method for manufacturing a liquid crystal display device according to claim 7, wherein the semiconductor film, the low-resistance semiconductor film, and the barrier metal film are continuously formed. 10. The first insulating film, the second insulating film, the high resistance semiconductor film, the low resistance semiconductor film, and the barrier metal film are formed by masking a part of the scanning signal wiring. The method for manufacturing a liquid crystal display device according to claim 9, wherein: