JPH10229196A - Active matrix display device - Google Patents

Abstract

(57) [PROBLEMS] To provide an active matrix display device provided with a highly reliable array substrate, which prevents diffusion of impurities such as moisture from a peripheral portion of the array substrate. SOLUTION: An array substrate 1 provided in an active matrix display device of the present invention has a protection structure in which a first insulating film 7 made of a silicon oxide film is made of a silicon nitride film having a smaller water diffusion coefficient than the silicon oxide film. Impurities such as water diffuse through the first insulating film 7 which is completely covered with the insulating film 15 or the conductor film 13b constituting the pad electrode and extends to the first region of the array substrate 1. It can prevent penetration. Therefore,
Even in a severe use environment such as high temperature and high humidity, fluctuation and deterioration of the characteristics of the thin film transistor can be prevented, and stable characteristics can be maintained for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an active matrix type display device in which thin film transistors are formed in an array, and more particularly to an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, flat display devices such as liquid crystal display devices have attracted attention as new display devices replacing CRTs. Liquid crystal display devices are widely used as display devices for various electronic devices such as home appliances, personal computers, EWS, and portable information terminals because of their thinness and low-power operation.

A liquid crystal display device performs display by two-dimensionally modulating transmitted light or reflected light by arranging pixels formed by sandwiching a liquid crystal layer between a pair of electrodes in a matrix. Things.

In an active matrix type liquid crystal display device, each pixel is constituted by sandwiching a liquid crystal layer between a pixel electrode connected to a non-linear switching element such as a thin film transistor and a counter electrode, thereby providing a higher definition display. Is possible.

FIG. 13 is a diagram schematically showing a configuration of an active matrix type liquid crystal display device. FIG. 14 is a diagram schematically showing a cross-sectional structure in the AA ′ direction of the liquid crystal display device of FIG. This liquid crystal display device has a liquid crystal layer 93 sandwiched between an array substrate 91 and a counter substrate 92.
In the display area of the array substrate 91, pixel electrodes connected to the thin film transistors are arranged in a matrix. The array substrate 91 is larger than the opposing substrate 92, and
A pad electrode 94 for connecting an external circuit such as a driving IC is formed in a peripheral portion of the display area. FIG.
5 is an enlarged view of a portion of the pad electrode 94.

FIG. 16 is an enlarged view showing a pixel portion of the liquid crystal display device illustrated in FIGS. In the array substrate 91, a gate electrode 96 is formed on an insulating substrate 95 such as glass, and a silicon oxide film (SiOx) 97, a silicon nitride film (SiNx) 98, and a semiconductor film 99 formed on the gate electrode 96. Are laminated. An etching stopper 100 is formed on the channel of the semiconductor film 99.
Are formed, and a source electrode 102 and a drain electrode 103 are formed in a source-side contact region and a drain-side contact region of the semiconductor film 99 via an ohmic contact layer 101. Also, the source electrode 102
Are formed in connection with the pixel electrode 104 formed of ITO or the like. Further, a protective insulating film 105 is formed from above the source electrode 102 and the drain electrode 103.

On the other hand, the counter substrate 92 has a counter electrode 107 made of ITO or the like formed on an insulating substrate 106 made of glass or the like.

The drain electrode 103 is connected to a signal line (not shown). When the thin film transistor 106 is turned on by the gate electrode 96, the display signal voltage applied to the signal line is applied to the pixel electrode 10 through the source / drain electrodes.
4 is applied to the liquid crystal layer and the electric field formed between the liquid crystal layer and the counter electrode 107 controls the alignment state of the liquid crystal layer to modulate the light incident on the pixel.

FIG. 17 is a diagram schematically showing a cross-sectional structure of a peripheral region of a display pixel region where a pad electrode portion of the array substrate 91 is formed. FIG. 17A shows a cross-sectional structure in the BB 'direction. 17 (b) is a view schematically showing a cross-sectional structure in the CC ′ direction (see FIG. 15). The manufacturing process of such an array substrate 91 will be described with reference to FIGS. FIGS. 18 to 20 are views for explaining such a conventional method of manufacturing an array substrate, and show a cross-sectional structure of a thin film transistor in a display pixel portion and a cross-sectional structure in a BB ′ direction of a pad electrode portion during a manufacturing process. FIG. 4 is a view schematically showing a cross-sectional structure in the direction of arrows CC and CC ′.

First, a gate electrode 96 and a low-resistance conductive film serving as a gate line (not shown) are formed on the entire surface of a transparent insulating substrate 95 made of glass or the like, and are patterned into a predetermined shape (FIG. 18A). .

Next, an SiOx film 97 and a SiNx 98 are sequentially laminated on the entire surface of the substrate by a method such as plasma CVD as a gate insulating film, and further, a semiconductor film 99 and an etching stopper 100 are sequentially laminated. Next, the etching stopper 100 is patterned into a predetermined shape (FIG. 18).
(B)).

Subsequently, an ohmic contact layer 101 is formed, and the semiconductor layer 99 is patterned into a predetermined shape (FIG. 18C). SiOx film 97 as gate insulating film
When a laminated film of SiNx and SiNx98 is used, the semiconductor layer 99
And SiNx 98 do not have sufficient selectivity, so that the SiNx layer 98
Is also etched, and the SiOx film 97 is exposed on the entire surface except for the region where the semiconductor layer 99 is left in an island shape.

After that, the ITO (I
A transparent conductive film such as Nd Tin Oxide is formed and patterned into a predetermined shape (FIG. 19).
(D)).

Further, a contact hole (not shown) for contacting the gate line is formed. Next, the source electrode 102, the drain electrode 103, the signal line 103b
Is formed and patterned into a predetermined shape (FIG. 19E).

Further, the source electrode 102 and the drain electrode 1
The remaining ohmic contact layer 101 is removed by etching (FIG. 19F).

Thereafter, a protective insulating film is formed and patterned into a predetermined shape (FIG. 20 (g)). A pad electrode 94 is formed on the periphery of the array substrate 91 formed in such a process to connect a driving IC, so that the protective insulating film 105 does not remain on the entire surface of the array substrate 91. In the peripheral portion of the array substrate 91, the SiOx film 97 formed below the gate insulating film is exposed.

In general, an SiOx film formed by plasma CVD or the like does not have a sufficient stopping power against moisture and other impurities. SiO exposed around the array substrate 91
When impurities such as moisture are absorbed by the x film 97, the impurities diffuse into the display region over time. Thin film transistor 1
When impurities such as moisture diffuse into the portion 08, there is a problem that the characteristics of the thin film transistor 108 are remarkably fluctuated or deteriorated. When the characteristics of the thin film transistor 108 are deteriorated, there is a problem that the display quality of the liquid crystal display device is deteriorated and a display failure occurs.

As described above, the area around the array substrate 91,
If a thin film having insufficient stopping power against moisture and other impurities such as a SiOx film 97 formed by plasma CVD or the like on the end surface of the array substrate 91 is exposed, display defects due to diffusion of impurities such as moisture may occur. This causes a problem of deteriorating the display screen quality and long-term reliability of the liquid crystal display device.

[0019]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. That is, the present invention provides an active matrix type display device including a switching element such as a thin film transistor and a highly reliable array substrate having stable characteristics of an array thereof by preventing impurities such as moisture from penetrating into a gate insulating film. The purpose is to do. It is another object of the present invention to provide a highly reliable liquid crystal display device having stable characteristics of a thin film transistor.

[0020]

According to the present invention, there is provided an active matrix display device comprising: an insulating substrate having a first region; a second region formed on an outer peripheral portion of the first region; A gate electrode formed in a first region of the conductive substrate;
A semiconductor film in which carriers are induced by an electric field applied to the gate electrode; a thin film transistor having a source electrode and a drain electrode in ohmic contact with the semiconductor film; and a silicon oxide film formed on the insulating substrate and substantially formed of silicon oxide. A first insulating film that is formed of a film and insulates the gate electrode and the semiconductor film of the thin film transistor; and a second region formed on the insulating substrate so as to cover the thin film transistor in a first region. An array substrate including a second insulating film formed to cover the surface and the end face of the first insulating film and having a smaller diffusion coefficient of water than the first insulating film is provided.

An insulating substrate having a first region and a second region formed on an outer peripheral portion of the first region; a gate electrode formed in the first region of the insulating substrate; A thin film transistor having a semiconductor film in which carriers are induced by an electric field applied to the gate electrode, a source electrode and a drain electrode in ohmic contact with the semiconductor film, and a first region and a second region of the insulating substrate. A first insulating film substantially formed of a silicon oxide film in a region, the first insulating film insulating the gate electrode of the thin film transistor from the semiconductor film, and a first insulating film formed in the first region. The film and the insulating film formed in the second region may be formed separately.

The second insulating film only needs to have a lower diffusion coefficient of water than the first insulating film and have an insulating property. For example, a silicon nitride film (SiNx) can be used.

That is, in the array substrate provided in the active matrix type display device of the present invention, the first portion such as a silicon oxide film or the like which does not have sufficient stopping power against moisture and other impurities is provided around the display pixel region (second region). In order to prevent the insulating film from being exposed, the insulating film is covered with a second insulating film having a higher water stopping power than the first insulating film. Also, the first
Is formed separately in the first region and the second region, and even if impurities such as moisture permeate the first insulating film in the second region, the first region, which is a display pixel region, is formed. It does not affect the area.

According to the present invention, by adopting such a structure, a thin film having insufficient stopping power such as SiOx film is covered with a protective insulating film, and a thin film having insufficient stopping power is formed on the second substrate of the array substrate. No portion is exposed in the region. Generally, SiNx or the like formed by a plasma CVD method or the like is used for the protective insulating film. SiNx is S
The ability to stop moisture and the like is much greater than iOx. With such a structure, a thin film having insufficient stopping power can be diffused to prevent impurities such as moisture from entering the gate insulating film of the thin film transistor, and deterioration of characteristics of the thin film transistor can be prevented.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an array substrate provided in an active matrix display device of the present invention will be described in more detail.

(Embodiment 1) FIG. 1 is a view schematically showing an example of a configuration of a liquid crystal display device which is an active matrix type display device of the present invention. FIG. 2 is a diagram schematically showing a cross-sectional structure in the direction DD ′ of the liquid crystal display device of FIG. This liquid crystal display device has a liquid crystal layer 3 sandwiched between an array substrate 1 and a counter substrate 2. In the display pixel area (first area) of the array substrate 1, pixel electrodes connected to the thin film transistors are arranged in a matrix. Array substrate 1
Is larger than the counter substrate 2, and a pad electrode 4 for connecting an external circuit such as a driving IC is formed in a second area around the display pixel area of the array substrate 1.
FIG. 3 is an enlarged view of the pad electrode 4.
A pad-shaped electrode for connecting a gate line connected to the gate electrode of the thin film transistor or a signal line connected to the drain electrode of the thin film transistor to an external circuit such as a driving circuit is exposed.

FIG. 4 is an enlarged view showing a pixel portion of a liquid crystal display device using the array substrate of the present invention. In the array substrate 1, a gate electrode 6 is formed on an insulating substrate 5 such as glass, and a silicon oxide film (SiOx) 7, a silicon nitride film (SiNx) 8,
A semiconductor film 9 made of a-Si (amorphous silicon) is stacked. An etching stopper 10 is formed on a channel of the semiconductor film 9, and a source electrode 12 and a drain electrode 13 are formed on a source-side contact region and a drain-side contact region of the semiconductor film 9 via an ohmic contact layer 11. ing. Also, the source electrode 12
Are formed in connection with the pixel electrodes 14 formed of ITO or the like. A protective insulating film 15 made of a silicon nitride film (SiNx) is formed from above the source electrode 12 and the drain electrode 13.

On the other hand, in the counter substrate 2, a counter electrode 17 made of ITO or the like is formed on a light-transmitting insulating substrate 16 such as glass.

The drain electrode 13 is connected to a signal line (not shown).
6 is turned on, a display signal voltage applied to the signal line is applied to the pixel electrode 14 through the drain electrode 13 and the source electrode 12, and an electric field formed between the counter electrode 17 and the display signal voltage causes the alignment state of the liquid crystal layer 3. Is controlled, and the light incident on the pixel is modulated.

FIG. 5 is a diagram schematically showing a cross-sectional structure of a peripheral region (second region) of a display pixel region in which pad electrode portions are formed on array substrate 1 provided in the display device of the present invention. FIG. 5A shows a cross-sectional structure in the FF ′ direction, and FIG.
4 is a view schematically showing a cross-sectional structure in the EE ′ direction (see FIG. 3). In the array substrate 1 of the active matrix type display device of the present invention, the first insulating film 7 made of a silicon oxide film is a protective insulating film 15 made of a silicon nitride film whose diffusion coefficient of water is much smaller than that of the silicon oxide film. Alternatively, it is completely covered with the conductor film 13b constituting the pad electrode. Therefore, it is possible to prevent impurities such as water from diffusing and permeating through the first insulating film 7 extending to the first region. Further, since the end face of the first insulating film 7 is also covered, impurities such as water do not permeate from the end face of the array substrate, for example. Therefore, the active matrix display device of the present invention can prevent the characteristics of the thin film transistor from fluctuating or deteriorating, and can maintain stable characteristics for a long period of time even in a severe use environment such as high temperature and high humidity. In particular, by applying the present invention to a liquid crystal display device, an imaging device, and the like, the reliability of the device can be greatly improved.

(Embodiment 2) Next, a method of manufacturing an array substrate provided in the active matrix display device of the present invention will be described. FIGS. 6, 7, and 8 are views for explaining a manufacturing process of an array substrate included in the active matrix display device of the present invention, and show a cross-sectional structure of a display pixel portion and a peripheral portion of the array substrate in an EE ′ direction. Cross-sectional structure and FF '
It is a figure which shows the cross-sectional structure of a direction schematically.

First, a low-resistance metal film serving as a gate electrode 6 is formed on a transparent insulating substrate 5 such as non-alkali glass by sputtering or the like, and is patterned into a predetermined shape by photo-etching or the like. (FIG. 6A).

Next, an SiOx film 7 and a SiNx film 8 are sequentially formed as a gate insulating film by a plasma CVD method or the like. A-Si that becomes the semiconductor layer 9 continuously
The layer and the etching stopper 10 are formed by a method such as plasma CVD. Further, after patterning the etching stopper 10 into a predetermined shape (FIG. 6B), an n + a-Si layer to be the ohmic contact layer 11 is formed. Subsequently, the ohmic contact layer 11 and the semiconductor layer 9 are patterned into a predetermined shape (FIG. 6C). The semiconductor layer 9 made of a-Si is formed of SiNx in the upper layer of the gate insulating film.
Since the film 8 does not have sufficient etching selectivity, the SiNx film 8 in the upper layer of the gate insulating film is also etched and removed in this step. Furthermore, the IT that becomes the pixel electrode 14
A transparent conductive film such as O is formed by a sputtering method or the like, and is patterned into a predetermined shape (FIG. 7D).

Next, in order to form a contact between a gate line (not shown) and the gate-side pad electrode 6, the SiOx film 7 serving as a gate insulating film is etched. Usually, in this step, the insulating film is etched only at the contact portion between the gate line and the gate-side pad electrode 6. Therefore, the gate insulating film remains on the entire surface except for the contact portion. The gate insulating film (in this case, the SiOx film 7) is exposed in the second region in the peripheral portion of the array substrate even after being combined with the counter substrate 2, and impurities such as moisture penetrating therefrom cause the display pixel region to be exposed. The characteristics of the thin film transistor formed in the first step fluctuate greatly or deteriorate.

In the array substrate 1 provided in the active matrix type display device of the present invention, Si is formed to form a contact portion between the gate line and the gate-side pad electrode 6.
When the Ox film 7 is etched, the SiOx film 7 existing in the second region, which is the peripheral portion of the array substrate 1, is also etched (FIG. 7E). By performing such a process, the SiOx film 7 serving as the gate insulating film is covered with the protective insulating film 15 to be formed later, and is not exposed on the surface and the end surface of the array substrate 1, thereby preventing invasion of moisture and the like. be able to. SiO in the second region
After removing the x film 7 so as not to be exposed from the surface and the end surface of the array substrate, the source electrode 1
2. A low-resistance conductor film for forming the drain electrode 13, the signal line 13b, and the pad electrode 4 is formed and patterned into a predetermined shape (FIG. 7F).

Next, the ohmic contact layer 11 remaining between the source and drain electrodes is removed by etching (FIG. 8G).

Then, as the protective insulating film 15, an insulating film such as a SiNx film having an excellent ability to block impurities such as moisture is formed by a CVD method or the like, and is patterned into a predetermined shape (FIG. 8 (h)). . At this time, as described above, the protective insulating film 15 is formed so as to completely cover the SiOx film 7 formed in the second region.

When such an array substrate is applied to a liquid crystal display device, a highly reliable liquid crystal display device that operates stably for a long period of time even in a severe use environment such as high temperature and high humidity. Further, in order to manufacture an array substrate included in the active matrix display device of the present invention, it is only necessary to change a mask in an etching step when forming a contact portion between a gate-side pad electrode and a gate line. There is no need to increase the number. Therefore, the reliability of the array substrate and the display device can be improved without lowering the productivity.

(Embodiment 3) FIG. 9 is a view schematically showing another example of the structure of the array substrate provided in the active matrix type display device of the present invention. The FF 'in the second region of the array substrate 1 is shown. FIG. 10 is a diagram schematically showing a cross-sectional structure in a direction (FIG. 9A) and a cross-sectional structure in an EE ′ direction (FIG. 9B).

The array substrate 1 illustrated in FIG. 9 is obtained by forming an SiOx film 7 as a first insulating film separately in a first region and a second region. The thin film transistor 1 formed in the first region of the first insulating film
The portion continuous with the gate insulating film 8 is covered with the protective insulating film 15 or the signal line 13b. Therefore,
Even if impurities such as moisture diffuse and permeate into the SiOx film 7, which is the first insulating film exposed on the surface or the end face of the array substrate 1, these impurities do not affect the first region. Characteristics of the thin film transistor can be stably maintained. Further, if such an array substrate is applied to a liquid crystal display device or the like, a highly reliable liquid crystal display device that operates stably for a long period of time even in a severe use environment such as high temperature and high humidity.

(Embodiment 4) Next, a method of manufacturing an array substrate provided in the active matrix display device of the present invention having the structure described in Embodiment 3 will be described. FIG.
FIG. 11 is a diagram for explaining a manufacturing process of an array substrate included in the active matrix display device of the present invention.
Cross-sectional structure of display pixel portion, EE ′ in peripheral portion of array substrate
FIG. 2 is a diagram schematically showing a cross-sectional structure in a direction FF and a cross-sectional structure in an FF ′ direction.

Gate electrode 6, SiO x film 7, S
An iNx film 8, a semiconductor film 9, and an etching stopper layer are formed, patterned into a predetermined shape, an ohmic contact layer 11 is formed, patterned into a predetermined shape, and then a transparent conductive material such as ITO serving as a pixel electrode 14 is formed. The manufacturing method described in the second embodiment is the same as the manufacturing method described in the second embodiment up to the point where the conductive film is formed by sputtering or the like and patterned. The array substrate in this state is shown in FIG.
(Equivalent to (d)).

The difference from the method of manufacturing an array substrate provided in the active matrix type display device of the present invention described with reference to FIGS. 6 to 8 is that a gate insulating film is formed to form a contact between a gate line and a gate-side pad electrode. This is only the step of etching the SiOx film 7.

That is, in the method of manufacturing an array substrate included in the active matrix display device of the present invention described in the second embodiment, the S substrate formed in the second region of the array substrate 1
Although the iOx film 7 was entirely removed by etching, in this example, as shown in FIG. 10B, the SiOx film 7, which is a gate insulating film, was etched in a groove shape, and the first region was removed. What is necessary is just to isolate | separate from a 2nd area | region.

Thereafter, in the process of forming and patterning the protective insulating film 15, the protective insulating film 15 is completely covered with the above-mentioned groove (FIG. 11E). As a result, even if impurities such as moisture enter the SiOx film 7 exposed on the pad electrode portion, the SiOx film 7 is coated so as to be separated by the protective insulating film 15, so that impurities such as moisture are contained in the display region. Diffusion is prevented, and display failure does not occur.

Even in such a manufacturing method, it is only necessary to change the mask in the etching step when forming the contact portion between the gate-side pad electrode and the gate line.
There is no need to increase the number of steps. Therefore, the reliability of the array substrate and the display device can be improved without lowering the productivity.

(Embodiment 5) FIG. 12 is a view schematically showing still another example of the structure of the array substrate provided in the active matrix type display device of the present invention, and the thin film transistor in the first region of the array substrate 1 is shown. Cross-sectional structure of forming part, second
10A and 10B schematically show a cross-sectional structure in the FF ′ direction and a cross-sectional structure in the EE ′ direction (FIG. 9B) of the region of FIG.
In the array substrate included in the active matrix display device of the present invention illustrated in FIG. 12, a substrate protection film 5b made of silicon nitride is formed on an insulating substrate 5, and a thin film transistor and the like are formed on the substrate protection film 5b. Have been. By forming such a substrate protective film 5b, diffusion of alkali is prevented, and a substrate made of less expensive alkali glass can be used. Further, the SiOx film 7 in the second region is composed of the substrate protection film 5b and the protection insulating film 1b.
5 or the conductor film 13b.
Even if impurities such as moisture diffuse and permeate the iOx film 7, these impurities do not affect the first region, and the characteristics of the thin film transistor can be stably maintained. Further, when such an array substrate is applied to a liquid crystal display device, a highly reliable liquid crystal display device that operates stably for a long period of time even in a severe use environment such as high temperature and high humidity.

[0048]

As described above, according to the active matrix type display device of the present invention, the peripheral portion (second region) of the display pixel region is formed of a silicon oxide film or the like having an insufficient stopping power against moisture and other impurities. The second insulating film has a higher moisture stopping power than the first insulating film so that the first insulating film is not exposed.
By providing the array substrate covered with the insulating film, a highly reliable display device that operates stably for a long period of time even in a severe use environment such as high temperature and high humidity.

Further, since the first insulating film is formed separately in the first region and the second region, impurities such as moisture penetrate into the first insulating film in the second region. However, the first region, which is a display pixel region, is not affected and a highly reliable display device that operates stably for a long period of time even in a severe use environment such as high temperature and high humidity.

The active matrix type display device of the present invention having such a structure prevents a thin film having insufficient stopping power from diffusing to prevent the entry of impurities such as moisture into the gate insulating film of the thin film transistor. In addition, deterioration of characteristics of the thin film transistor can be prevented.

Further, the array substrate provided in the active matrix type display device of the present invention can be manufactured only by changing the mask in the etching step when forming the contact portion between the gate-side pad electrode and the gate line. There is no need to increase the number of steps. Therefore, the reliability of the array substrate and the display device can be improved without lowering the productivity.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an example of a configuration in which an active matrix display device of the present invention is applied to a liquid crystal display device.

FIG. 2 is a diagram schematically showing a cross-sectional structure in a DD ′ direction of the liquid crystal display device of FIG. 1;

FIG. 3 is an enlarged view of a pad electrode portion.

FIG. 4 is an enlarged view showing a pixel portion of a liquid crystal display device to which the active matrix display device of the present invention is applied.

FIG. 5 is a diagram schematically showing a cross-sectional structure of a peripheral region (second region) of a display pixel region in which a pad electrode portion is formed, of an array substrate 1 provided in an active matrix display device of the present invention; FIG. 5A is a diagram schematically illustrating a cross-sectional structure in the FF ′ direction, and FIG. 5B is a diagram schematically illustrating a cross-sectional structure in the EE ′ direction.

FIG. 6 is a diagram for explaining a manufacturing process of an array substrate included in the active matrix display device of the present invention.

FIG. 7 is a diagram for explaining a manufacturing process of an array substrate included in the active matrix display device of the present invention.

FIG. 8 is a diagram illustrating a manufacturing process of an array substrate included in the active matrix display device of the present invention.

FIG. 9 is a diagram schematically showing another example of the structure of an array substrate included in the active matrix display device of the present invention.

FIG. 10 is a diagram illustrating a manufacturing process of an array substrate included in the active matrix display device of the present invention.

FIG. 11 is a diagram illustrating a manufacturing process of an array substrate included in the active matrix display device of the present invention. .

FIG. 12 is a view schematically showing still another example of the structure of the array substrate included in the active matrix display device of the present invention.

FIG. 13 is a diagram schematically illustrating a configuration of an active matrix liquid crystal display device.

FIG. 14 is a diagram schematically showing a cross-sectional structure in the AA ′ direction of the liquid crystal display device of FIG. 13;

FIG. 15 is an enlarged view showing a portion of a pad electrode.

FIG. 16 is an enlarged view showing a pixel portion of the liquid crystal display device illustrated in FIGS. 13 to 15;

FIG. 17 is a diagram schematically showing a cross-sectional structure of a peripheral region of a display pixel region where a pad electrode portion of an array substrate is formed.

FIG. 18 is a view for explaining a conventional method of manufacturing an array substrate.

FIG. 19 is a view for explaining a conventional method of manufacturing an array substrate.

FIG. 20 is a view for explaining a conventional method of manufacturing an array substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Array substrate, 2 ... Counter substrate 3 ... Liquid crystal layer, 4 ... Pad electrode 5 ... Transparent insulating substrate, 5b ... Substrate protective film 6 ... Gate electrode, 7 ... ... SiOx film (first insulating film) 8... SiNx film 9... Semiconductor film 10. Etching stopper 11. Ohmic contact layer 14... Pixel electrode 12... Source electrode 13. Drain electrode 15 Protective insulating film 16 Insulating substrate 17 Counter electrode 18 Thin film transistor

Claims (1)

[Claims] An insulating substrate having a first region and a second region formed in an outer peripheral portion of the first region; a gate electrode formed in the first region of the insulating substrate; A thin film transistor having a semiconductor film in which carriers are induced by an electric field applied to the gate electrode, a source electrode and a drain electrode in ohmic contact with the semiconductor film, and substantially silicon formed on the insulating substrate. A first insulating film made of an oxide film and insulating the gate electrode and the semiconductor film of the thin film transistor; and a second region on the insulating substrate so as to cover the thin film transistor in a first region. An array substrate including a second insulating film formed so as to cover the surface and the end face of the first insulating film and having a smaller water diffusion coefficient than the first insulating film. Active matrix type display device.