JP2001059978A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device ensuring high reliability and excellent picture quality using minimum number of photomasks and utilizing wiring materials which are produced at a low cost. SOLUTION: In a liquid crystal display device provided with scanning signal electrodes 10, 11 and video signal electrodes 14 intersecting the scanning signal electrodes on an insulation substrate 1 and thin film transistors adjacent to the intersections of the scanning signal electrodes 10, 11 and the video signal electrodes 14, the scanning signal electrodes 10, 11 are constituted of a laminated layer of a Ta electrode 10 and an Al electrode 11. Anodically oxidized films 20, 21 are formed on the surface and the side face of the laminated layer. External connection terminal parts are formed by removing the upper layer Al electrode 11 with etching using the anodically oxidized films 20, 21 as masks, and by exposing only the Ta electrode 10. An a-Si:H layer 30 and a gate SiN layer 22 are worked so as to form the same pattern. Controlling hillocks on the surface reduces defective short circuit. The external connection terminals with high corrosion resistance are realized. The above-mentioned structure is formed in one time photo process so as to simplify the manufacturing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin film transistor (TFT) active matrix type liquid crystal display device used as a display device of image information / character information of an OA device or the like, and particularly to a wiring material thereof.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device in which TFTs are formed in a matrix on an insulating substrate such as glass and used as switching elements is expected as a flat panel display with high image quality.

At present, there are several problems to be solved in a TFT active matrix display.

[0004] The first problem is to improve the production yield. In particular, a short circuit failure between the scanning signal wiring and the video signal wiring is the largest cause of the failure, and reduction of the failure has been a problem.

A second problem is to reduce the number of manufacturing steps.
In particular, there is a strong demand for a reduction in the number of photolithography steps.

A third problem is a technique for forming a low-resistance scanning signal wiring which can cope with high definition and large screen size.

[0007] A fourth problem is to ensure reliability. Specifically, it is an issue to secure not only reliability of image quality but also reliability against corrosion of external connection terminals of wiring.

Various proposals have been made to solve the above problems.

As for the first problem of improving the manufacturing yield, for example, Japanese Patent Application Laid-Open No. 61-133662 discloses that a gate insulating film of a TFT is formed of an anodized film of a gate electrode and a SiN film.
It discloses a technique of forming a layered structure to prevent a short circuit between wirings due to a pinhole or the like in a gate insulating film (first related art).

Many proposals have been made for the second problem of reducing the number of photolithography steps. For example, Japanese Patent Application Laid-Open No. 63-9977 discloses a structure in which a scanning line has a two-layer structure of a transparent electrode and a metal film, and a pixel electrode is formed by the transparent electrode of the scanning line. In this method, since the scanning signal wiring and the pixel electrode can be formed by one patterning, the photolithography process can be reduced (second conventional technique).

Japanese Patent Application Laid-Open No. 62-32651 discloses a method of reducing the number of photolithography steps by processing a gate insulating film and a semiconductor film constituting a TFT into the same pattern using one photomask. It is disclosed (third prior art).

Regarding the third problem of forming a low-resistance scanning signal wiring, Japanese Patent Laid-Open No. 2-85826 discloses, for example,
An example is disclosed in which 1 is used as a scanning wiring and an Al ₂ O ₃ film is used as a gate insulating film and an interlayer insulating film. Low resistance A
When 1 is used as the scanning wiring, the delay of the scanning signal can be suppressed to a level that causes no practical problem even if the load on the scanning wiring increases due to higher definition / larger screen (fourth prior art).

Further, Japanese Patent Application Laid-Open No. 64-35421 discloses A
1 and Ta formed on Al are used for scanning wiring,
And an anodic oxide film of Ta and Ta are used as a gate insulating film and an interlayer insulating film to reduce the resistance of scanning wiring, reduce interlayer short-circuit defects, and reduce the number of processes (fifth conventional technique). ).

[0014]

In order for TFT active matrix type liquid crystal display devices to become widely used, it is necessary to simultaneously solve all the above-mentioned problems and realize high image quality, low cost, and high reliability. However, the above prior art is
Although each of the objectives has achieved a certain effect, each elemental technology often has a trade-off relationship with each other, and it is not possible to satisfy all of the above-mentioned objectives at the same time. Further, simply combining the above-described individual techniques causes a new problem, and the desired effect cannot be obtained. The situation will be explained.

For example, when the first prior art and the second prior art are combined, it is necessary to anodize the scanning signal wiring metal on the transparent electrode. When a metal is anodized on a transparent conductive film, there is a problem that the metal film is dissolved by a battery reaction due to a difference in standard potential of the material. Further, in order to form a resist mask for selective oxidation at the time of anodic oxidation, a new photomask is required, so that the second problem of reduction in the number of steps cannot be achieved.

In the second prior art, the semiconductor film as the active layer has a structure that protrudes outside the gate electrode.
When a display device is configured, a backlight or external light hits the semiconductor film which has protruded outside the gate electrode, and the photocurrent of the semiconductor film increases the leak current of the TFT and deteriorates image quality. In order to prevent this deterioration in image quality, it is effective to reduce the thickness of the semiconductor film. However, as is well known, in order to reduce the thickness of a semiconductor film using a conventional inverted staggered TFT due to process restrictions, a photomask for forming a channel protective film for protecting a channel portion of the TFT requires one photomask. I have to add more. Regarding this problem, for example, see “Flat Panel Display '91” (Nikkei BP
(1990), pp. 88-96.

Therefore, in the second prior art, the mask of the semiconductor film and the gate insulating film is integrated to reduce the photomask to one.
Although it is possible to reduce the number of wafers, it is necessary to reduce the thickness of the semiconductor film in order to guarantee image quality that can be used practically, and it is necessary to increase the number of photomasks by one to form a channel protective film. As a result, Process simplification cannot be achieved by reducing the photomask.

When the third prior art and the fourth prior art are combined, the scanning signal wiring is a transparent electrode and a low resistance wiring A
It has a two-layer structure with 1 electrode. In this case, the Al electrode is used as it is for the external connection terminal portion of the scanning signal wiring, or the upper layer of Al is selectively removed, and the transparent electrode is used as the external connection terminal.

Since the external connection terminal portion of the wiring is exposed to various solvents and the like even after the post-process such as liquid crystal encapsulation, there is a problem that when an active metal such as Al is used, it is corroded. Further, when a transparent electrode is used for the terminal portion, when the transparent electrode which is a metal oxide and the Al of the wiring metal are joined,
Since Al is oxidized by oxygen in the transparent electrode to form an insulating film at the interface, there is a problem that contact reliability is extremely low.

In the fifth prior art, T is added on Al.
Since a is formed, there is no problem of contact, but since Al is also exposed on the side surface of the terminal, there is a problem that corrosion is likely to occur.

Due to the above problems, A
When l is used, a barrier metal is often inserted between the terminals in order to maintain good contact with the transparent electrode at the terminal portion. However, a new photomask is required to process the barrier metal. Therefore, the second
However, it is not possible to achieve the reduction in the number of steps, which is an issue of the above.

Further, generally, a gate insulating film and a semiconductor film of a TFT are formed at a temperature of about 300 ° C. by a plasma vapor deposition method (PCVD). A for scanning signal wiring
When 1 is used, a large number of surface irregularities called hillocks grow due to the thermal history in the PCVD process. An electric field is concentrated on such irregularities, and the withstand voltage between the scanning signal wiring and the video signal wiring is extremely reduced. Therefore, when low-resistance Al is used for the scanning signal wiring, it is difficult to achieve the first problem of improvement in manufacturing yield.

As described above, the mere combination of the conventional techniques cannot simultaneously solve all of the above-mentioned problems.

An object of the present invention is to provide a liquid crystal display device using a wiring material which can be manufactured at low cost while securing high reliability and good image quality with a minimum number of photomasks.

[0025]

In order to achieve the above object, the present invention provides a scanning signal electrode formed on an insulating substrate, a video signal electrode formed to cross the scanning signal electrode, and a scanning signal electrode. In a liquid crystal display device including a signal electrode and a thin film transistor formed near an intersection of a video signal electrode, the scan signal electrode is formed of a metal first conductive film and Al or Al disposed on the first conductive film. A second conductive film of an alloy as a main component is connected to an external drive circuit, and a connection terminal portion between the external drive circuit and the scanning signal electrode includes a first conductive film and a first conductive film. The second conductive film at the end of the scanning signal electrode is composed of an insulating film and a transparent conductive film extending from a connection terminal portion between the external drive circuit and the scanning signal electrode. Coated with membrane And it has proposed a liquid crystal display device.

The second conductive film can be mainly covered with the insulating film on the upper surface and mainly on the side surface with the transparent conductive film.

It is desirable that the first conductive film of the scanning signal electrode and the first conductive film of the connection terminal part are formed continuously.

According to another aspect of the present invention, there is provided a scanning signal electrode formed on an insulating substrate, a video signal electrode formed to cross the scanning signal electrode, In a liquid crystal display device including a thin film transistor formed near a crossing point of a signal electrode, the scanning signal electrode mainly includes a first conductive film of metal and Al or Al disposed on the first conductive film. The second conductive film of the alloy is formed by etching using the insulating film formed on the second conductive film as a mask, and is connected to an external drive circuit. Is composed of a first conductive film and a transparent conductive film disposed on the first conductive film. The transparent conductive film of the connection terminal portion is formed on the second conductive film of the scanning signal electrode. Insulating film formed on It proposes a liquid crystal display device which is formed extending to the upper.

Also in this case, it is desirable that the first conductive film of the scanning signal electrode and the first conductive film of the connection terminal portion are formed continuously.

In any of the above cases, the transparent conductive film is specifically ITO.

In the present invention, since a wiring material including an Al film or an alloy film containing Al as a main component is used, generation of hillocks on the Al surface can be suppressed. Therefore, a short circuit between wirings can be reduced when a display device or the like is configured. Such a phenomenon has not been known so far, and has been clarified for the first time by experiments by the inventors.

When the multilayer wiring is used for the scanning signal electrode of the liquid crystal display device, the interlayer dielectric strength between the scanning signal electrode and the video signal electrode increases. As a result, short-circuit defects can be reduced, and the resistance of the scanning signal electrode can be reduced, so that the display screen can be made large in size and high in definition.

When the surface of Al is entirely covered with an insulating film containing Al as a base material, the aluminum is not exposed to chemicals and the like, so that corrosion resistance can be ensured.
Hillock generation on the Al surface can be further suppressed.

When the external connection terminal is constituted by one metal and a transparent conductive film composed of a metal oxide formed thereon, the chemical resistance of the terminal is improved and an insulating barrier formed by a reaction between the transparent conductive film and the metal. Layers are less likely to form at the interface. Therefore, an increase in the contact resistance of the connection terminal can be prevented, and a highly reliable connection terminal can be obtained.

Such a structure can be formed by removing Al by etching using the insulating film formed on the Al surface as a mask. Therefore, the above structure can be formed with only one photomask, and at the same time, the effects of reducing the number of steps, ensuring corrosion resistance, reducing short-circuit defects, and reducing the resistance of the scanning signal electrode can be obtained.

A pixel electrode made of a transparent conductive film is arranged below the semiconductor film and the gate insulating film, and the semiconductor film and the gate insulating film are extended along the video signal electrode as a pattern wider than the video signal electrode. If only the peripheral portion of the electrode pattern is covered, the pixel electrode and the video signal electrode can be separated. In this way, even if the distance between the pixel electrode and the video signal electrode is reduced while preventing the short circuit between the pixel electrode and the video signal electrode, pixel defects due to the short circuit can be reduced. Further, the width of the pixel electrode is increased, and the pixel aperture ratio is improved. Therefore, in addition to features such as a reduction in the number of processes, a high yield, low resistance wiring, and an improvement in the reliability of the terminals, low defects,
A high-brightness liquid crystal display device can be realized.

The inventors have found that, after forming a Ta film, if an Al film is continuously formed in a vacuum while keeping the surface cleanliness in particular, the (111) orientation becomes weak and the (220)
They found that the surface grew preferentially, and at the same time, the hillocks on the film surface became smaller. The production method of the present invention is based on this finding. That is, in the manufacturing method of the liquid crystal display device of the present invention, Al growing on the Ta surface is not affected by the adsorbing layer and is directly affected by the underlying Ta film, and thus does not occur under normal conditions (220). Priority growth of the surface is realized. When the (220) plane grows preferentially, the orientation changes randomly as a whole, and the hillocks on the film surface decrease.

The features and / or effects of other modifications of the present invention will become apparent from the following description of embodiments.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 is a perspective view of one embodiment of a laminated wiring material of a liquid crystal display device according to the present invention. The laminated wiring material of this embodiment is made of Ta by magnetron sputtering.
The film 10 and the Al film 11 are sequentially laminated on the glass substrate 1,
Processed and formed into the same pattern.

The upper Al film 11 has a crystal orientation oriented to the (220) plane under the influence of the underlayer. It is conventionally known that when Al, which is a face-centered cubic lattice (fcc), is grown on (110) of Ta having a body-centered cubic lattice (bcc), it is oriented to (111). In the experiments by the inventors, when the Al film 11 is continuously formed in a vacuum after the Ta film 10 is formed, particularly while keeping the surface clean, the (111) orientation becomes weak and the (220) The surface was found to grow preferentially. At the same time, it was discovered that the hillocks on the membrane surface were reduced.

FIG. 2 is a diagram showing a comparison between the surface irregularities of the Al film 11 formed on the glass substrate 1 and the Ta film 10 respectively. In the Al film 11 formed on the glass substrate 1, some hillocks having a height of about 100 nm are observed, whereas in the Al film 11 formed on the Ta film 10,
Although many minute irregularities are generated, no large hillocks are observed. This difference is probably due to the fact that Al grows under the influence of a Ta base having fine crystal grains, and as a result, the crystal grains do not grow large, so that the internal stress of the film is alleviated. It is presumed that many minute hillocks are generated.

To grow the (220) plane, care must be taken during film formation. Experiments have confirmed that the (220) orientation does not appear unless Ta and Al are grown continuously without leaving any time while maintaining the cleanliness of the Ta surface. After the Ta film is formed, once the discharge is stopped and left for several minutes or more, even if the vacuum is not released, the T
An adsorbed layer of H ₂ O or the like is formed on the surface a, and preferential growth of the (220) plane does not occur. The inventors obtained (220) orientation for the first time by slowly moving Ta and Al in a chamber during sputtering. In such a method, Ta and Al are continuously formed while being slightly mixed near the interface.
No adsorption layer of H ₂ O or the like is formed on the surface. That is, Al growing on the Ta surface is not affected by the adsorbed layer and is directly affected by the underlying Ta film, so that preferential growth of the (220) plane, which does not occur under normal conditions, is realized.

FIG. 3 is a diagram showing a comparison between the X-ray diffraction pattern of the Al thin film used for the wiring of the present invention and the X-ray diffraction pattern of the conventional Al film. The height of the peak of the diffraction pattern is proportional to the volume of the crystal grain oriented so that the plane indicated at the position of each peak is parallel to the film surface. (22
The intensity ratio between the diffraction peak of (0) and the diffraction peak of (111) is
In the conventional Al film, the value was 0.15, but in the Al film of the present invention, the value was 0.7 or more. Conventional A
It can be seen that the diffraction peak from the (220) plane is larger and the diffraction peak from the (111) plane is smaller in the Al film of the present invention than in the 1 film. In the conventional Al film, (1
It is considered that the crystal grains strongly oriented in the 11) plane are changed to random orientation as a whole by the growth of the (220) plane in the Al film of the present invention. That is, the ratio of the intensity of the surface having the largest diffraction peak intensity to the intensity of the surface having the second highest intensity is, for example, about 0.5 in the conventional Al film.
However, in the present invention, it is about 0.7 to 1.0.
For this reason, it is assumed that the average crystal grain size became slightly smaller, the variation in the grain size became smaller, and the grain size became uniform.

Conventionally, in Al wirings used in LSIs, if the crystal grains of Al are miniaturized, the resistance to electromigration and stress migration is reduced. Therefore, Al is preferentially oriented to (111) to increase the crystal grains. ing. In such an Al film, a large hillock grows due to a small number of triple points of crystal grains serving as sites for relaxing stress. In a TFT array for a liquid crystal display device, the wiring width is about 10 μm, which is larger than that of an LSI, so that electromigration and stress migration do not cause much problems.
Rather, it is important to suppress hillocks on the Al surface to suppress interlayer short circuits. Therefore, (220) of the present invention
The suppression of hillocks due to the orientation and the miniaturization of the crystal grains is due to T
It is very desirable as a wiring for an FT array.

FIG. 4 is a diagram showing the relationship between the intensity ratio of the (220) diffraction peak and the (200) diffraction peak obtained from the X-ray diffraction of the Al film and the surface hillock density.
It can be seen that the hillock density decreases as the (220) / (200) ratio increases, and that the hillocks almost disappear when the (220) / (200) ratio exceeds 1.0.

As the material of the base, not only Ta but also b
Any metal having a crystal structure of cc may be used. For example, T
a-N alloy, Nb, Ta-Nb alloy, Nb-N alloy, T
Similar effects can be obtained with a-Nb-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta-W alloy, and Ta-W-N alloy. Further, the material of the upper layer is not limited to pure Al, but may be made of A-Pd, Al-Ta, Al-Ta-Ti, etc.
1 alloy film may be used.

The Al film of the present invention has a clean surface T
In addition to the method that can be grown on the alloy containing a and forms a film continuously after forming the base film, there is also a method of performing film formation after cleaning the formed base surface by sputter etching or the like. Can be adopted.

[0048]

[Embodiment 2] FIG. 5 is a plan view of a scanning signal wiring for a liquid crystal display device formed by using the above-mentioned laminated wiring material of the present invention. FIG. 6 is a sectional view of an external connection terminal portion of the scanning signal wiring of FIG. FIG. 7 is a cross-sectional view of the AA plane of FIG. 6 as viewed from the direction of the arrow.

A Ta electrode 10 and an Al electrode 11 are formed on a glass substrate 1 and their surfaces and side surfaces are made of Ta ₂ O _5.
It is covered with a film 20 and an Al ₂ O ₃ film 21. Here, the Al ₂ O ₃ film 21 is formed so as to cover the entire surface of the Al electrode 11 which is the upper layer film of the two-layer conductive film. Further, the Al electrode 11, which is the upper layer film, is formed from a position which is at least a distance X from the end of the scanning signal electrode (distance X
Was set to 1.0 cm in this example), and the Al electrode 11 was excluded from the end portion in contact with the external member.

According to the present embodiment, the scan electrode is covered with a low resistance A electrode while completely covering the easily corroded Al electrode with the Al ₂ O ₃ film and removing it from the end in contact with the external member.
Since one electrode can be used, high definition / large size of the display device is achieved. In order to reliably connect to the external member, X may be set to 0.1 cm or more. In addition, Al
A highly corrosion-resistant Ta is arranged under the electrode, and Al ₂ O ₃
A structure in which the end faces of the film and the Al electrode are made coincident with each other, and Al ₂ O
_Since the external connection terminals are formed by etching and removing the Al electrodes at the ends using the _three films as masks, a photomask for metal-working the connection terminals becomes unnecessary, and the number of steps can be reduced. Further, since the (220) -oriented Al electrode having few hillocks is used as the upper layer film, interlayer short-circuit failure can be reduced. As described above, since a high-quality Al ₂ O ₃ film can be used as an interlayer insulating film, interlayer short-circuit defects can be further reduced.

[0051]

Third Embodiment FIG. 8 is a sectional view showing an end of another embodiment of the scanning signal electrode of the liquid crystal display device according to the present invention.
FIG. 9 is a cross-sectional view of the AA plane of FIG.

The scanning signal electrode of this embodiment has two layers of Ta.
It is composed of a three-layered conductive film consisting of an electrode 10 and an Al electrode 11 sandwiched therebetween. As in the above embodiment, the surfaces and side surfaces of these films are made of Ta ₂ O ₅ film 20 and Al ₂ O ₃
The surface of the Ta electrode 10, which is covered with the film 21 and is the uppermost film, is entirely covered with the Ta ₂ O ₅ film 20. In addition, the Ta electrode 10 and the Al electrode 11 of the upper layer were formed at a position separated from the end of the scanning signal electrode by a distance of 1.0 cm or more, and the Al electrode 11 was excluded from the end in contact with the external member.

According to the present embodiment, in addition to the same effects as in the first embodiment, the Ta ₂ O ₅ film having a large relative dielectric constant can be used as a part of the gate insulating film of the TFT.
The transconductance of the TFT is improved. Further, the generation of hillocks in the Al electrode 11 can be further suppressed by the Ta electrode 10 in the upper layer, and interlayer short-circuit failure can be reduced.

[0054]

[Embodiment 4] FIG. 10 is a schematic sectional view of a unit pixel of a liquid crystal display device constituted by using a scanning signal electrode having the structure of Embodiment 2.

A scanning signal electrode comprising a Ta electrode 10 and an Al electrode 11 is formed on a glass substrate 1, and the surface and side surfaces thereof are covered with a Ta ₂ O ₅ film 20 and an Al ₂ O ₃ film 21. I have. Si on these scanning signal electrodes
N film 22, a-Si: H film 30, n-type a-Si: H film 31
Are formed, and a video signal electrode 14 and a source electrode 15 are formed on the n-type a-Si: H film 31, and a pixel electrode 13 made of an ITO film is connected to the source electrode. A capacitance electrode 16 is connected to the pixel electrode 13, and the scanning signal electrode 11 and the capacitance electrode 16 form an additional capacitance. Further, the whole is covered with a protective SiN film 23.

FIG. 11 is a sectional view of the external connection terminal of the scanning signal electrode of the thin film transistor substrate. Here, of the scanning signal electrodes, the surface of the upper Al electrode 11 is made of Al ₂
Coated with O ₃ film 21, thereby extending the Ta electrode 10 to the outside of the _Al 2 _{O 3} film 21, and constitutes the external connection terminals.
The Ta electrode 10 is covered with an ITO electrode 13. In the present embodiment, since the barrier layer formed at the Ta / ITO interface due to the reaction between Ta and ITO is not completely insulative, the contact resistance between Ta and ITO is lower than that when, for example, Al and ITO are combined. , Is much smaller. In addition, in the case of Ta and ITO, since the contact resistance hardly increases due to the heat treatment, an extremely stable connection terminal can be obtained.

In this embodiment, Ta is used as the base metal. However, in addition to Ta, Ta-N alloy, Nb, Ta-Nb
Alloy, Nb-N alloy, Ta-Nb-N alloy, Ta-Ti
Alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta-
Similar effects can be obtained with a WN alloy or the like. In particular, Ta
When metal nitrides such as -N and Ti-N are used, metals and IT
The reaction of O can be further suppressed, and the contact resistance can be extremely reduced.

FIGS. 12 to 16 are views showing the steps of manufacturing the thin-film semiconductor device of the above embodiment. The right side of these figures is a diagram showing a cross section in each step of the scanning signal electrode terminal portion.

In FIG. 12, Ta is placed on the glass substrate 1.
The film 10 and the Al film 11 are successively deposited by sputtering, and are patterned into a predetermined shape by using a photolithography technique.

In FIG. 13, Ta is used for the anodic oxidation method.
A Ta ₂ O ₅ film 20 and an Al ₂ O ₃ film 21 are formed on the surface and side surfaces of the film 10 and the Al film 11.

In FIG. 14, using the Al ₂ O ₃ film 21 as a mask, the Al film 11 in the scanning signal electrode terminal portion is removed by etching to expose the Ta electrode 10. At this time, according to the reactive ion etching method using a mixed gas plasma of hydrogen bromide (HBr) and boron trichloride (BCl ₃ ), the etching selectivity between Al and Ta can be increased, so that the etching work margin is increased. The degree increases, and the yield improves. Subsequently, an ITO film is deposited by sputtering, and is patterned by using a photolithography technique to form the pixel electrode 13 and the protective film 131 of the terminal Ta.

In FIG. 15, a gate SiN film 22, an a-Si: H film 30, an n-type a
-Si: H film 31 is deposited, a-Si: H film 30, n-type a
The -Si: H film 31 is patterned into a predetermined shape, and then the gate SiN film 22 on the pixel electrode 13 and the terminal electrode is removed.

In FIG. 16, a Ti film is deposited by sputtering and patterned into a predetermined shape to obtain a video signal electrode 14, a source electrode 15, and a capacitor electrode 16. Finally, the protective SiN film 23 is formed by the plasma CVD method.
Is formed to complete the thin film semiconductor device.

According to the present embodiment, Ta having high corrosion resistance can be used for the external connection terminal, so that high reliability can be ensured. Further, since the Ta electrode of the external connection terminal portion is exposed using the Al ₂ O ₃ film as a mask, a photomask for processing the external connection terminal metal, which has been conventionally required, becomes unnecessary, and the number of steps can be reduced. Furthermore, by suppressing hillocks on the Al surface, interlayer short-circuits are reduced, and a low-resistance Al electrode can be used as the scanning signal electrode, so that a higher definition and larger size of the liquid crystal display device can be realized.

In the above embodiment, Ta is applied to the scanning signal electrode.
And Al were used, but the present invention is not limited to this combination.
Instead of W, Nb and alloys containing these, such as T
The same applies to the case where aN, Nb-N, Ta-Nb-N, Ta-Ti-N, or the like is used. Not only pure Al but also A
An alloy such as 1-Pd, Al-Ta, Al-Ti-Ta may be used.

Further, in the above-described embodiment, the method of exposing the Ta electrode of the external connection terminal is adopted by using the Al ₂ O ₃ film formed on the surface of Al as a mask, but the Ta electrode of the external connection terminal is exposed. The step may be performed after removing the gate SiN film 22 on the terminal portion electrode. Also in this case, the photoresist for processing the gate SiN film 22 can be used as a mask for exposing the Ta electrode 10 as it is, so that the number of steps does not increase.

The gate SiN film and the Al ₂ O ₃ film are not directly exposed to the plasma for exposing the Ta electrode.
Since no plasma damage occurs in the film, good insulating properties can be maintained.

[0068]

Embodiment 5 The wiring material according to the present invention can be applied not only to scanning signal wiring but also to video signal wiring. FIG.
FIG. 3 is a cross-sectional view of a pixel in an embodiment in which a wiring material according to the present invention is applied to a video signal wiring. In the present embodiment, in addition to the structure of the first embodiment, the video signal wiring, the source electrode, and the capacitor electrode are made of Ta films 141, 151, 161 and Al.
It consists of laminated electrodes of the films 142, 152, 162. By adopting such a structure, the Al films 142, 15
Since 2,162 has the (220) orientation, the growth of whiskers and hillocks from the Al film due to the heat treatment at the time of forming the protective film 23 can be prevented for the reason already described.

[0069]

[Embodiment 6] FIG. 18 is a sectional view of a pixel portion of another embodiment of a liquid crystal display device constituted by using the scanning signal electrodes having the structure of Embodiment 2 shown in FIG. FIG. 19 is a plan view of the embodiment of FIG.

As in the embodiment, a scanning signal electrode composed of a Ta electrode 10 and an Al electrode 11 is formed on a glass substrate 1. The surface and side surfaces of these electrodes are covered with a Ta ₂ O ₅ film 20 and an Al ₂ O ₃ film 21. On these scanning signal electrodes, a 400 nm-thick SiN film 22 and a 50 nm-thick a-Si: H film 30 are formed in the same plane, and the video signal electrode 14 is formed on the a-Si: H film 30. And a source electrode 15 are formed. The pixel electrode 13 made of an ITO film is connected to the source electrode 15.

The pixel electrode 13 is disposed below the SiN film 22, and the a-Si: H film 30 and the SiN film 22 extend below the video signal electrode 14 along the video signal electrode 14. The a-Si: H film 30 and the SiN film 22 form the pixel electrode 1
Only the peripheral portion of the pattern No. 3 is covered. Pixel electrode 1
3, the scanning electrode 11 and the capacitor electrode 16 form an additional capacitor. These are all covered with a protective SiN film 23.

FIG. 20 is a sectional view taken along the line AA in FIG.
FIG. 4 is a diagram showing a concentration distribution in the depth direction of ³¹ P and ¹¹ B in an a-Si: H film 30. FIG. 21 is a diagram showing the concentration distribution in the depth direction of ³¹ P and ¹¹ B in the a-Si: H film 30 in the BB section in FIG.

In the BB section in contact with the source electrode 15, only ³¹ P is introduced with a sharp concentration profile that decreases exponentially from the surface. Also, TFT
The A-A cross-section that is the channel region, substantially equal amounts of ³¹
P and ¹¹ B have been introduced.

With the above configuration, the present embodiment has the following effects in addition to the effects described above.

A. The a-Si: H film 30 and the gate SiN film 31, which have been conventionally patterned by separate photomasks,
Since one photomask is patterned into the same shape, the number of photolithography steps is reduced by one, so that the number of steps can be reduced and the manufacturing cost can be reduced.

B. The channel region of the TFT is ³¹ P
^Since 11B is mutually compensated to increase the resistance, the source electrode and the drain electrode can be separated without etching the n-type a-Si: H film, which was conventionally required, so that a-Si: H
The thickness of the film 30 can be reduced. When the thickness of the a-Si: H film 30 is 60 nm or less, a decrease in the off-resistance of the TFT due to a photocurrent can be prevented, and a good image quality can be obtained. Also, a
-The formation of a channel protective film, which was conventionally required when thinning the Si: H film 30, becomes unnecessary, and the number of manufacturing steps does not increase.

C. Since the pixel electrode 13 and the video signal electrode 14 are separated by the a-Si: H film 30 and the gate SiN film 22, the pixel electrode 13 and the video signal electrode 14 are not short-circuited. For this reason, it is possible to reduce pixel defects mainly caused by a short circuit between the pixel electrode 13 and the video signal electrode 14. Further, the distance between the pixel electrode 13 and the video signal electrode 14 can be reduced, and the area of the pixel electrode 13 can be increased accordingly, and the pixel aperture ratio can be improved. As a result, high brightness of the display can be achieved.

FIGS. 22 to 29 are sectional views showing the manufacturing steps of the embodiment of FIG.

In FIG. 22, Ta is placed on the glass substrate 1.
The film 10 and the Al film 11 are deposited by sputtering, and are patterned into a predetermined shape using a photolithography technique. Next, the Ta ₂ O ₅ film 20 and the Al ₂ O ₃ film 2 are formed on the surface and side surfaces of the Ta film and the Al film by anodization.
And 1.

In FIG. 23, an ITO film is deposited to a thickness of 110 nm by sputtering and patterned to form a pixel electrode 13.

In FIG. 24, a gate SiN film 22 is deposited to a thickness of 400 nm by plasma CVD, and a-S
An i: H film 30 is formed to a thickness of 50 nm.

[0082] In FIG. 25, by irradiating PH + without mass separation withdrawn from the discharge plasma of PH ₃ gas, the ions of the PH ₂ +, etc. with a low energy of about 2 keV, a-
P is introduced into the Si: H film 30. As an impurity doping technique using an ion beam without mass separation, for example, a method using a magnetic bucket type ion source is disclosed in Japanese Patent Application Laid-Open No. 2-199824.

In FIG. 26, the gate SiN film 22 and the a-Si: H film 30 are processed into the same planar shape by photolithography.

In FIG. 27, a Ti electrode is formed by sputtering and patterned to form a video signal electrode 14.
And the source electrode 15 and the capacitor electrode 16 are obtained.

In FIG. 28, ions of BH +, B ₂ H ₂ +, etc., which are not mass-separated, are irradiated at a low energy of about 2 keV using the pattern of the video signal electrode 14 and the source electrode 15 as a mask, and a-Si: H B is introduced into the channel region of the film 30. This can be easily realized by using a B-containing gas such as B ₂ H ₆ as the discharge gas in the above-described technique.

In FIG. 29, a protective SiN film is formed to complete the device.

When the above-described manufacturing process is employed, the formation of the channel protective film, which was conventionally required when the a-Si: H film 30 is thinned, becomes unnecessary as described above. it can. In particular, when a low-energy ion beam without mass separation is used as an impurity introduction method, impurities can be efficiently introduced into a large area, so that production efficiency is improved.

FIG. 30 is an equivalent circuit of a TFT substrate in the liquid crystal display device of the present invention. On a glass substrate 1, a plurality of scanning signal electrodes 10/11, a plurality of video signal electrodes 14 orthogonal to the scanning signal electrodes 10/11, and a TFT connected to these electrodes.
And a liquid crystal capacitor and an additional capacitor connected to the TFT. Scanning signal electrode 10/11 and video signal electrode 1
A terminal 140 for connecting an external member is provided at one of the ends of the terminal 140.

To display an image, the scanning signal electrode 10 /
A pulse signal is sequentially applied to 11 to turn on one row of TFTs, and during that time, an image signal is applied from the video signal electrode to the liquid crystal layer. This operation is repeated for each row.

FIG. 31 is an equivalent circuit of another TFT substrate in the liquid crystal display device of the present invention. A plurality of scanning signal electrodes 10 and 11, a plurality of video signal electrodes 14 orthogonal to the scanning signal electrodes 10 and 11, and a TFT connected to these electrodes are provided on the glass substrate 1.
And a portion composed of a liquid crystal capacitor and an additional capacitor connected to the TFT are the same as those in the above example, but in the present embodiment, a scanning signal circuit 200 for driving the TFT is provided on the glass substrate 1. And the video signal circuit 210
It is formed using FT. As described above, since the driving circuit is also integrated on the glass substrate 1, the number of external components is significantly reduced, so that the overall cost can be significantly reduced. Of course, even when the number of such external connection terminals is small, the wiring material of the present invention can be similarly applied.

In the embodiment described above, an example using an inverted staggered thin film transistor has been described. However, the wiring material of the present invention is not limited to this, and may be applied to a thin film transistor having a staggered or coplanar electrode structure. It is similarly applicable and can achieve similar effects.

FIG. 32 is a diagram showing a schematic cross section of a liquid crystal display device constituted by the thin film semiconductor device according to the present invention.
The center part in FIG. 32 shows a cross section of one pixel part, and the left part
The left side of the pair of glass substrates 1 and 508 shows a cross section of a portion where an external lead-out terminal exists, and the right side shows the right side of the pair of glass substrates 1 and 508 shows a cross section of a portion where no external lead-out terminal exists. ing.

On the lower glass substrate 1 with reference to the liquid crystal layer 506, the scanning signal electrodes 11 and the video signal electrodes 14 are formed in a matrix. The TFT formed near the intersection drives the pixel electrode 13 made of ITO.
Opposing glass substrate 508 that faces the liquid crystal layer 506
A counter electrode 510 made of ITO, a color filter 507, a color filter protective film 511, and a light shielding film 512 serving as a light shielding black matrix pattern are formed thereon. The sealing material S shown on each of the left and right sides in FIG.
L is formed along the entire edge of the glass substrates 1 and 508 except for a liquid crystal sealing port (not shown) so as to seal the liquid crystal layer 506. The sealing material is, for example, an epoxy resin.

The counter electrode 510 on the counter glass substrate 508 side
Is connected to an external lead wire formed on the glass substrate 1 by a silver paste material SIL at least at one place. The external connection wiring is formed in the same manufacturing process as each of the scanning signal wiring 10, the source electrode 15, and the video signal electrode 14. Each layer of the alignment films ORI1, ORI2, the pixel electrode 13, the protection film 23, the color filter protection film 511, and the gate SiN film 21 is formed inside the sealing material SL. The polarizing plate 505 is formed on the outer surfaces of the pair of glass substrates 1 and 508, respectively.

The liquid crystal layer 506 is sealed between the lower alignment film ORI1 and the upper alignment film ORI2 for setting the direction of the liquid crystal molecules, and is sealed by the sealing material SL. The lower alignment film ORI1 is formed above the protective film 23 on the glass substrate 1 side. On the inner surface of the opposite glass substrate 508,
Light shielding film 512, color filter 507, color filter protection film 511, counter electrode 510, upper alignment film ORI2
Are sequentially laminated.

In this liquid crystal display device, the layers on the glass substrate 1 side and the layer on the counter glass substrate 508 side are separately formed, and then the upper and lower glass substrates 1 and 508 are overlapped, and the liquid crystal 506 is sealed between the two. Can be When the transmission of light from the backlight BL is adjusted at the pixel electrode 13, the TFT
A driving type color liquid crystal display device is formed.

Since the liquid crystal display device of the present invention can use a scanning signal electrode made of low-resistance Al, it is suitable for enlargement and high definition. In addition, since it can be manufactured with a simple manufacturing process with a high yield, the cost can be significantly reduced, and an inexpensive liquid crystal display device can be provided.

The following is an example of the characteristic configuration of the present invention.

1. An Al film having a volume ratio of 0.5 or more between crystal grains oriented so that the (220) plane is parallel to the film surface and crystal grains oriented so that the (200) plane is parallel to the film surface, or A wiring material including an alloy film containing Al as a main component.

2. An Al film in which the volume ratio between crystal grains oriented so that the (220) plane is parallel to the film surface and crystal grains oriented so that the (111) plane is parallel to the film surface is 0.5 or more; A wiring material including an alloy film containing Al as a main component.

3. A wiring material in which the ratio of the volume of crystal grains having the second orientation direction, which has the second highest content, to the volume of crystal grains having the first orientation direction, which has the highest content, is approximately 0.5 or more.

4. Ta, Ta-N alloy, Nb, Nb-N
Alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-T
i-alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta
A first conductive film made of one metal of the -WN alloy, and a second conductive film made of Al or an alloy containing Al as a main component and formed on the first conductive film. Laminated wiring material.

5. In the multilayer wiring material according to the above 4, the crystal grains oriented so that the (220) plane included in the Al film or the alloy film containing Al as a main component is parallel to the film surface and the (200) plane are formed on the film surface. A multilayer wiring material having a volume ratio of 0.5 or more to crystal grains oriented so as to be parallel to the multilayer wiring material.

6. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, at least one of a scanning signal electrode and a video signal electrode is formed by crystal grains having a (220) plane oriented parallel to a film surface and a (200) crystal grain. The volume ratio with the crystal grains oriented so that the plane is parallel to the film surface,
A liquid crystal display device formed of a wiring material including an Al film having a thickness of 0.5 or more or an alloy film containing Al as a main component.

7. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device including a pixel electrode and driving liquid crystal by a thin film transistor, at least one of a scanning signal electrode and a video signal electrode is made of Ta, a Ta-N alloy,
Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N
Alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta
A first conductive film made of one of a -W alloy and a Ta-W-N alloy, and a second conductive film formed on the first conductive film made of Al or an alloy containing Al as a main component. A liquid crystal display device formed of a laminated wiring material composed of a film.

8. 7. In the liquid crystal display device according to the above 7, the Al is contained in Al or an alloy mainly containing Al (2
20) A liquid crystal display device wherein the volume ratio between crystal grains oriented so that the plane is parallel to the film surface and crystal grains oriented so that the (200) plane is parallel to the film surface is 0.5 or more.

9. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. In a liquid crystal display device comprising a pixel electrode and driving liquid crystal by a thin film transistor, a scanning signal electrode is
It is a laminated film of two or more conductive films including at least an Al film or an alloy film containing Al as a main component, and is composed of Ta, Ta-N alloy, Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb.
-N alloy, Ta-Ti alloy, Ta-Ti-N alloy, W,
A liquid crystal display device in which a conductive film made of one of a Ta-W alloy and a Ta-W-N alloy is disposed above and below an Al film or an alloy film containing Al as a main component.

10. 10. The liquid crystal display device according to any one of the above items 6 to 9, wherein a coating insulating film containing Al as a base material is formed on the surface and side surfaces of the Al film or an alloy film containing Al as a main component.

11. 10. The liquid crystal display device according to any one of the items 6 to 9, wherein the Al film or the alloy film containing Al as a main component is present only at a position separated by 0.1 cm or more from one end of the scanning signal electrode.

12. 12. The liquid crystal display device according to any one of the items 6 to 11, wherein a film constituting at least one of the scanning signal electrode and the video signal electrode is a gate electrode of a thin film transistor.

13. 13. The liquid crystal display device according to any one of the above items 6 to 12, wherein the insulating film containing Al as a base material comprises:
A liquid crystal display device that is an Al oxide film or a nitride film.

14. A scanning signal electrode formed on an insulating substrate, a video signal electrode formed to cross the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a pixel connected to the thin film transistor In a liquid crystal display device having an active matrix substrate composed of electrodes and an external drive circuit connected to the active matrix substrate and driving liquid crystal by a thin film transistor, a connection terminal between the external drive circuit and a video signal electrode or a scanning signal electrode Is Ta, Ta-N alloy,
Nb, Nb-N alloy, Ta-Nb alloy, Ta-Nb-N
Alloy, Ta-Ti alloy, Ta-Ti-N alloy, W, Ta
A liquid crystal display constituted by a first conductive film made of one of a -W alloy and a Ta-W-N alloy, and a transparent conductive film made of a metal oxide formed on the first conductive film. apparatus.

15. A scanning signal electrode comprising the wiring according to any one of the above items 1 to 5, a gate insulating film of a thin film transistor formed on the scanning signal electrode, a semiconductor film formed on the gate insulating film, and an intersection with the scanning signal electrode. In a liquid crystal display device comprising a video signal electrode formed so as to form a pixel electrode connected to a thin film transistor, and driving a liquid crystal by the thin film transistor, a semiconductor film and a gate insulating film in contact with the semiconductor film have the same plane. A liquid crystal display device having a shape.

16. 16. The liquid crystal display device according to the item 15, wherein the semiconductor film and the gate insulating film in contact with the semiconductor film extend below the video signal electrode in a pattern wider than the video signal electrode.

17. 17. In the liquid crystal display device described in the above item 15 or 16, only one of n-type or p-type impurities is introduced into a region of the semiconductor film which is in contact with the source and drain metal electrodes, and the channel portion is introduced into the channel portion. A liquid crystal display device into which both n-type and p-type impurities are introduced.

18. 18. The liquid crystal display device according to any one of the items 15 to 17, wherein the semiconductor film has a thickness of 60 n.
A liquid crystal display device comprising any one of hydrogenated amorphous Si, hydrogenated amorphous SiGe, and hydrogenated amorphous Ge of m or less.

19. In the liquid crystal display device described in the above item 18, the concentration of the n-type and p-type impurities is 10 ²¹ cm ⁻³ or more at the surface of the semiconductor film and 10 ¹⁹ cm ⁻³ or less at the interface between the semiconductor film and the gate insulating film. A liquid crystal display device.

20. 20. The liquid crystal display device according to any one of the items 15 to 19, wherein the pixel electrode is disposed below the semiconductor film and the gate insulating film.

21. 21. The liquid crystal display device according to the item 20, wherein the semiconductor film and the gate insulating film cover only the outer peripheral portion of the pixel electrode pattern.

22. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. A method for manufacturing a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, comprising: a. Ta, Ta-N alloy, Nb, Nb-N
Alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-T
i-alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta
A first conductive film made of one of the -W-N alloys and Al or an alloy film containing Al as a main component are sequentially and sequentially laminated in a vacuum, processed into a predetermined pattern, and scanned. Forming at least one of an electrode and a video signal electrode; b. Forming an insulating film covering a part of the scanning signal electrode; c. A method for manufacturing a liquid crystal display device, comprising a step of removing only Al or an alloy film containing Al as a main component among conductive films constituting a scanning signal electrode using an insulating film as a mask.

23. 23. The method for manufacturing a liquid crystal display device according to the above item 22, wherein the insulating film is formed by any one of an anodic oxidation method, a plasma oxidation method, and a plasma nitridation method.

24. 23. The method for manufacturing a liquid crystal display device according to the above item 22, wherein the insulating film is formed by a plasma CVD method or a sputtering method.

25. 22. In the method for manufacturing a liquid crystal display device according to 22 above, the step of removing only Al or an alloy film containing Al as a main component in the conductive film forming the scanning signal electrode using the insulating film as a mask includes removing a hydrogen halide gas. A method for manufacturing a liquid crystal display device, which is an ion etching method using a mixed gas containing the same.

26. 23. The method for manufacturing a liquid crystal display device according to the above 22, wherein the first conductive film and Al or an alloy film containing Al as a main component are continuously formed while maintaining a vacuum.

27. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. A method for manufacturing a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, comprising: a. Ta, Ta-N alloy, Nb, Nb-N
Alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-T
i-alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta
Forming a first conductive film made of one of the -W-N alloys, and depositing Al or an alloy film containing Al as a main component on the first conductive film while keeping the surface of the first conductive film clean; Laminated,
Step of forming a scanning signal electrode or a video signal electrode by processing into a predetermined pattern b. Forming an insulating film covering a part of the scanning signal electrode or the video signal electrode; c. A method for manufacturing a liquid crystal display device, comprising a step of removing only Al or an alloy film containing Al as a main component among conductive films constituting a scanning signal electrode or a video signal electrode using an insulating film as a mask.

28. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. A method for manufacturing a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, comprising: a. Ta, Ta-N alloy, Nb, Nb-N
Alloy, Ta-Nb alloy, Ta-Nb-N alloy, Ta-T
i-alloy, Ta-Ti-N alloy, W, Ta-W alloy, Ta
Forming a first conductive film made of one metal of a -WN alloy; b. Removing a part of the surface layer of the first conductive film c. Laminating Al or an alloy film containing Al as a main component on the first conductive film from which a part of the surface layer has been removed; d. Processing the laminated film into a predetermined pattern to form a scanning signal electrode or a video signal electrode; e. Forming an insulating film covering a part of the scanning signal electrode or the video signal electrode; f. A method for manufacturing a liquid crystal display device, comprising a step of removing only Al or an alloy film containing Al as a main component among conductive films constituting a scanning signal electrode or a video signal electrode using an insulating film as a mask.

29. A scanning signal electrode formed on the insulating substrate, a video signal electrode formed to intersect the scanning signal electrode, a thin film transistor formed near an intersection of the scanning signal electrode and the video signal electrode, and a thin film transistor connected to the thin film transistor. A method for manufacturing a liquid crystal display device comprising a pixel electrode and driving a liquid crystal by a thin film transistor, comprising: a. A step of sequentially laminating a first conductive film and Al or an alloy film containing Al as a main component in vacuum on an insulating substrate and processing them into a predetermined pattern to form a scanning signal electrode; b. Forming an insulating film whose base material is a material constituting each conductive film on a part of the surface and side surfaces of the scanning signal electrode; c. A step of removing only Al or an alloy film containing Al as a main component of the conductive film forming the scanning signal electrode using the insulating film as a mask; d. A step of forming a transparent electrode film on the entire surface of the substrate and processing it into a predetermined shape to form a pixel electrode; e. Forming a gate insulating film and a semiconductor film on the entire surface of the substrate; f. A step of irradiating the semiconductor film with an ion beam containing phosphorus at an energy of 5 keV or less to introduce phosphorus into the semiconductor film; g. Step of processing the gate insulating film and the semiconductor film into the same pattern h. Step of depositing a conductive film and processing it into a predetermined pattern to form a video signal electrode and a source electrode i. A method for manufacturing a liquid crystal display device, comprising: irradiating a semiconductor film with an ion beam containing boron at an energy of 5 keV or less using a pattern of an image signal electrode and a source electrode as a mask to introduce boron into the semiconductor film.

30. 22. An information processing apparatus comprising the liquid crystal display device according to any one of the above items 6 to 21 as display means.

31. An information processing apparatus comprising, as a display means, a liquid crystal display device manufactured by the manufacturing method according to any one of the above items 22 to 29.

[0130]

According to the present invention, a large pixel aperture ratio having a small pixel defect density and a low pixel defect density is provided with a low-resistance scan signal electrode having few hillocks and an external connection terminal having high corrosion resistance in a minimum photolithography process. Thus, the liquid crystal display device can be simultaneously increased in size, increased in definition, and reduced in cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a laminated wiring material according to the present invention.

FIG. 2 is a diagram showing a comparison of surface irregularities of an Al film 11 formed on a glass substrate 1 and a Ta film 10 respectively.

FIG. 3 is a diagram showing an X-ray diffraction pattern of an Al thin film used for the wiring of the present invention in comparison with an X-ray diffraction pattern of a conventional Al film.

FIG. 4 is obtained from X-ray diffraction of the Al film (220)
FIG. 4 is a diagram showing the relationship between the intensity ratio of the diffraction peak of (1) and (200) diffraction peak and the surface hillock density.

FIG. 5 is a plan view of a scanning signal wiring for a liquid crystal display device formed using the laminated wiring material of the present invention.

6 is a sectional view of an external connection terminal portion of the scanning signal wiring of FIG.

FIG. 7 is a cross-sectional view of the AA plane of FIG. 6 as viewed from the direction of the arrow.

FIG. 8 is a sectional view showing an end of another embodiment of the scanning signal electrode of the liquid crystal display device according to the present invention.

9 is a cross-sectional view of the AA plane of FIG. 8 as viewed from the direction of the arrow.

10 is a schematic cross-sectional view of a unit pixel of a liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment shown in FIG.

FIG. 11 is a sectional view of an external connection terminal of a scanning signal electrode of the thin film transistor substrate.

FIG. 12 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section of each step of the scanning signal electrode terminal portion.

FIG. 13 is a view showing a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section of each step of the scanning signal electrode terminal portion.

FIG. 14 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section of each step of the scanning signal electrode terminal portion.

FIG. 15 is a diagram illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section of each step of the scanning signal electrode terminal portion.

FIG. 16 is a view illustrating a manufacturing process of the thin-film semiconductor device of the embodiment. The right side of the figure is a diagram showing a cross section of each step of the scanning signal electrode terminal portion.

FIG. 17 is a cross-sectional view of a pixel in an embodiment in which the wiring material of the present invention is applied to a video signal wiring.

18 is a cross-sectional view of a pixel portion of another embodiment of the liquid crystal display device configured using the scanning signal electrodes having the structure of the second embodiment shown in FIG.

FIG. 19 is a plan view of the embodiment of FIG.

20 is a diagram showing a concentration distribution in the depth direction of ³¹ P and ¹¹ B in the a-Si: H film 30 in the AA cross section in FIG. 18;

21 is a diagram showing the concentration distribution in the depth direction of ³¹ P and ¹¹ B in the a-Si: H film 30 in the BB section in FIG. 18;

FIG. 22 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 23 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 24 is a sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 25 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 26 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 27 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 28 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 29 is a cross-sectional view showing a manufacturing step of the embodiment in FIG. 18;

FIG. 30 is an equivalent circuit of a TFT substrate in the liquid crystal display device of the present invention.

FIG. 31 is an equivalent circuit of another TFT substrate in the liquid crystal display device of the present invention.

FIG. 32 is a diagram showing a schematic cross section of a liquid crystal display device constituted by the thin film semiconductor device according to the present invention.

[Explanation of symbols]

Reference Signs List 1 glass substrate 10 Ta electrode 11 Al electrode oriented on (220) plane 13 pixel electrode 14 video signal electrode 15 source electrode 16 capacity electrode 20 Ta ₂ O ₅ film 21 Al ₂ O ₃ film 22 gate SiN electrode 23 protective SiN film 30 a-Si: H film 31 n-type a-Si: H film 140 external connection terminals 141, 151, 161 Ta film 142, 152, 162 Al film 200 scanning signal circuit 210 video signal circuit 505 polarizing plate 506 liquid crystal layer 507 color filter 508 Counter glass substrate 510 Counter electrode 511 Color filter protective film 512 Light shielding film BL Backlight ORI Alignment film SL Seal material SIL Silver paste material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 29/78 617M

Claims (6)

[Claims] A scanning signal electrode formed on an insulating substrate; a video signal electrode formed to intersect with the scanning signal electrode; and a scanning signal electrode formed near an intersection of the scanning signal electrode and the video signal electrode. In a liquid crystal display device having a thin film transistor, the scan signal electrode includes a first metal conductive film and the first conductive film.
And a second conductive film of an alloy containing Al as a main component, which is disposed on the conductive film, and is connected to an external drive circuit. The connection terminal portion is composed of the first conductive film and a transparent conductive film disposed on the first conductive film. The second conductive film at an end of the scanning signal electrode is:
A liquid crystal display device comprising: an insulating film; and a transparent conductive film extending from a connection terminal portion between the external drive circuit and the scanning signal electrode. 2. The liquid crystal display device according to claim 1, wherein the second conductive film has an upper surface mainly covered with an insulating film and a side surface mainly covered with the transparent conductive film. Liquid crystal display. 3. The liquid crystal display device according to claim 1, wherein the first conductive film of the scanning signal electrode and the first conductive film of the connection terminal portion are formed continuously. A liquid crystal display device characterized by the above-mentioned. 4. A scanning signal electrode formed on an insulating substrate, a video signal electrode formed to intersect with the scanning signal electrode, and a video signal electrode formed near an intersection of the scanning signal electrode and the video signal electrode. In a liquid crystal display device having a thin film transistor, the scan signal electrode includes a first metal conductive film and the first conductive film.
And a second conductive film of Al or an alloy containing Al as a main component, which is formed by etching using the insulating film formed on the second conductive film as a mask, A connection terminal portion between the external drive circuit and the scanning signal electrode is configured by the first conductive film and a transparent conductive film disposed on the first conductive film. The liquid crystal display device, wherein the transparent conductive film of the connection terminal portion is formed to extend over an insulating film formed on the second conductive film of the scanning signal electrode. 5. The liquid crystal display device according to claim 4, wherein the first conductive film of the scanning signal electrode and the first conductive film of the connection terminal portion are formed continuously. Characteristic liquid crystal display device. 6. The liquid crystal display device according to claim 1, wherein the transparent conductive film is made of ITO.