JPH06230428A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To enable the formation of low-resistance scanning signal electrodes and external connecting terminals having high corrosion resistance to be realized and to prevent the disconnection of upper wirings so as to improve yield, by forming a second conductive film of a material which is higher in the coefft. of volumetric expansion at the time of growth of a self-anodized film than a first conductive film. CONSTITUTION:At least the signal electrode formed in the lower layer between the scanning signal electrodes 11 and video signal electrodes 14 consist of at least the two layers, that is, the first conductive film made of an alloy film having Al as main component or Al and the second conductive film formed in the lower layer of the first conductive film. In addition, the second conductive film is constituted of the material which is higher in the coefft. of volumetric expansion at the time of growth of the self-anodized film than the first conductive film. The volumetric expansion according to the growth of the oxidized film from the second conductive film is larger than the volumetric expansion following the growth of the oxidized film from the first conductive film and, therefore, an overhung state after the anodic oxidation is eliminated and the level difference formed by laminated wirings is relieved. Then, the disconnection of the upper layer wiring is prevented and the larger size, the higher fineness and the lower cost are realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure and manufacturing method of a thin film transistor active matrix type liquid crystal display device used as a display device for image and character information of OA equipment and the like.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device in which thin film transistors (hereinafter referred to as TFTs) are formed in a matrix on an insulating substrate such as glass and used as a switching element is expected as a high quality flat panel display. There is. At present, there is a strong demand for high definition, large size, and multi-gradation for the TFT active matrix type display. In order to meet these requirements, it is necessary to reduce the resistance of the scanning signal wiring in order to suppress the signal delay of the scanning signal wiring. At the same time, improving the manufacturing yield is also a major issue. In particular, reduction of short circuit defects between the scanning signal wiring and the video signal wiring is the most important issue. Furthermore, there is a strong demand for reduction in the number of photo processes for cost reduction.

To solve the above problems, Japanese Patent Laid-Open No. 64-35
In No. 421, the scanning signal wiring is formed by Al and T formed on Al.
By forming a two-layer structure of a and processing the two-layer electrode in one photo process and further forming an anodic oxide film on the surface, a scanning signal wiring with low resistance and good insulation characteristics at the wiring intersection is formed. Techniques for configuring are disclosed.

[0004]

In the above-mentioned prior art, since the scanning signal wiring having Al having a low resistivity and Ta anodic oxide film having a high insulation reliability can be formed by a minimum number of photo processes, the above-mentioned problems are solved. On the other hand, it is extremely effective. However, in the above-mentioned conventional technique, sufficient consideration has not been given to the problem caused by an increase in the level difference of the wiring as the wiring is multi-layered.

When the laminated film of Al and Ta as shown in FIG. 17 is anodized, the film thickness t _Al of the Al anodic oxide film (Al ₂ O ₃ ) is assumed to be the maximum applied voltage Va (V).

T _Al = 1.4Va (nm).

On the other hand, the film thickness t _Ta of the Ta anodic oxide film (Ta ₂ O ₅ ) is t _Ta = 1.7 Va (nm), and the growth film thickness of the oxide film per unit voltage is Ta ₂ O ₅ Is bigger. Therefore, when anodizing a laminated film in which Ta is laminated on Al, the growth rate of Ta ₂ O _{5 in} the upper layer is higher, and therefore FIG.
It becomes an overhang shape like.

Here, in the inverted staggered type TFT, the video signal electrode intersects so as to cross over the scanning signal electrode. Therefore, when the scanning signal electrode has such an overhang shape, the coverage at the step portion is covered. Becomes worse and disconnection is more likely to occur. In particular, such a laminated wiring has a large step due to the laminated structure, so that a step break at the step portion is more likely to occur. When using laminated wiring, it is necessary to fully consider this point.

An object of the present invention is to provide a laminated wiring structure and a manufacturing method capable of preventing a disconnection failure of the upper wiring.

[0010]

In order to achieve the above object, the present invention is provided with the following means.

(1) A scanning signal electrode formed on an insulating substrate, a video signal electrode formed so as to intersect the scanning signal electrode, and a thin film transistor formed near the intersection between the scanning signal electrode and the video signal electrode. A liquid crystal display device having a function of driving a liquid crystal by the pixel electrode, the scan signal being composed of an active matrix substrate including a pixel electrode connected to the thin film transistor, and an external driving circuit for driving the active matrix substrate. Among the electrodes and the video signal electrode, at least one of the signal electrodes formed in the lower layer is formed in the lower layer of the first conductive film and the first conductive film made of Al or an alloy film containing Al as a main component. At least two layers including the formed second conductive film, and the second conductive film is a self-oxidized film grown more than the first conductive film. Expansion coefficient is constituted by a large material.

(2) Scan signal electrodes formed on an insulating substrate, video signal electrodes formed so as to intersect the scan signal electrodes, and thin film transistors formed near the intersections of the scan signal electrodes and the video signal electrodes. A liquid crystal display device having a function of driving a liquid crystal by the pixel electrode, the scan signal being composed of an active matrix substrate including a pixel electrode connected to the thin film transistor, and an external driving circuit for driving the active matrix substrate. Among the electrodes and the video signal electrode, at least one of the signal electrodes formed in the lower layer is formed in the lower layer of the first conductive film and the first conductive film made of Al or an alloy film containing Al as a main component. One material selected from TaN, NbN, Ta-Nb-N alloy, Ta-Ti-N alloy and Ta-W-N alloy Consists of at least two layers comprising a second conductive film made of I, and was a composition ratio of N contained in the second conductive film is 50% or less than 25%.

(3) In the above (1) and (2), the surfaces and the side surfaces of the first and second conductive films are formed by self-oxidizing films of the materials forming the first and second conductive films, respectively. Coated.

(4) In the above (1) and (2), the scanning signal electrode is used as a gate electrode of the thin film transistor.

(5) In the above (1) and (2), the first conductive film is 0.1 cm from one end of the scanning signal electrode.
It was made to exist only in the position distant above.

(6) In the above (1) and (2), the connection terminal between the active matrix substrate and the external drive circuit is the second conductive film or the second conductive film and the second conductive film. It was composed of a transparent conductive film formed on the film.

(7) A method of manufacturing a liquid crystal display device including the following steps.

(I) A step of sequentially laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component in a vacuum on an insulating substrate.

(Ii) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film.

(Iii) Using the photoresist pattern as a mask, the first conductive film and the second conductive film are continuously patterned by a dry etching method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas. Process.

(Iv) A step of forming self-oxidized films of the patterned first conductive film and second conductive film on a part of the surfaces and side surfaces of the conductive films.

(8) A method of manufacturing a liquid crystal display device characterized by including the following steps is adopted. (I) A step of successively laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component in a vacuum on an insulating substrate.

(Ii) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film.

(Iii) patterning only the first conductive film by a wet etching method using the photoresist pattern as a mask.

(Iv) patterning the second conductive film by a dry etching method using a mixed gas plasma containing at least halogen gas or hydrogen halide gas, using the photoresist pattern as a mask.

(V) A step of forming a self-oxidized film of these conductive films on the surface and a part of the side surfaces of the patterned first conductive film and second conductive film.

(9) A liquid crystal display device manufacturing method characterized by including the following steps is adopted. (I) A step of successively laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component in a vacuum on an insulating substrate.

(Ii) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film.

(Iii) Using the photoresist pattern as a mask, the first conductive film and the second conductive film are continuously patterned by a dry etching method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas. Process.

(Iv) A step of forming a self-oxidized film of these conductive films on the surface and a part of the side surfaces of the patterned first conductive film and second conductive film.

(V) Using the self-oxidizing film as a mask, a dry method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas only in the first conductive film in a portion not covered with the self-oxidizing film. Step of etching away by etching method.

(10) In the method for manufacturing a liquid crystal display device according to (7) to (9), boron trichloride gas is used as a gas for patterning the first conductive film or the second conductive film by a dry etching method. And a mixed gas of hydrogen bromide gas were used.

(11) In the method of manufacturing a liquid crystal display device according to (9), the self-oxidation film is used as a mask to perform etching for removing the first conductive film in a portion not covered with the self-oxidation film. A mixed gas of boron trichloride gas and hydrogen bromide gas was used as the gas.

(12) In the liquid crystal display device according to the above (2), the nitrogen concentration in the second conductive film is the smallest near the interface with the first conductive film, and the nitrogen concentration in the interface with the first conductive film is low. The distribution is set to decrease with increasing distance from.

[0035]

As described in (1) above, at least 2 including a first conductive film made of Al or an alloy film containing Al as a main component and a second conductive film formed under the first conductive film. The second conductive film is made of a material having a volume expansion coefficient larger than that of the first conductive film during the growth of the self-oxidized film, so that the oxide film can be grown from the second conductive film. Since the accompanying volume expansion is larger than that due to the oxide film growth from the first conductive film, the overhang shape after anodization is eliminated, and the step formed by the laminated wiring is relaxed. Therefore, disconnection of the upper layer wiring can be prevented.

In particular, as described in (2) above, in the second conductive film, the composition ratio of N in the film is 25% or more and 50% or less, TaN, NbN, Ta-Nb-N alloy, Ta-. Ti
-N alloy and Ta-W-N alloy are used to form one material, so that the anodic oxidation of the second conductive film rather than the volume expansion accompanying the growth of the anodic oxide film of the first conductive film. The volume expansion accompanying the growth of the film can be made sufficiently large, the step can be significantly reduced, and the anodic oxide film having good insulating properties to be formed can be obtained, so that disconnection of the upper layer wiring can be prevented, Short circuit defects can be reduced.

Other features and effects of the present invention will be apparent from the following description.

[0038]

【Example】

Example 1 FIG. 1 is a perspective view of a laminated wiring used in an example of the present invention. Ta formed on a glass substrate by a sputtering method
_{A 1-x} N _x electrode 100 and an Al electrode 11 are sequentially laminated, and the surface and side surface of the _1-x N _x electrode 100 are Ta _1-x N _x and T which is an anodized film of Al
It is covered with an a ₂ O _x N _y film 201 and an Al ₂ O ₃ film 21. In this example, the N composition of Ta _1-x N _x was 45 atom%. With a nitrogenated alloy of a refractory metal typified by Ta _1-x N _x, etc., the volume expansion coefficient during anodic oxidation increases. Therefore, even if the Ta _1-x N _x electrode 100 before anodization and the Al electrode 11 have the same width by configuring the lower layer electrode of the laminated wiring with this material as in the present embodiment, Since the cross-sectional shape of the wiring after oxidation is stepwise, even if another wiring is formed in the upper layer, step disconnection does not occur. Figure 2
Shows the relationship between the N composition ratio in the Ta _1-x N _x film, the anode voltage Va during anodic oxidation, and the oxide film thickness. The anodic oxide film thickness increases with the N composition ratio, and especially when the N composition ratio is 25% or more, it rapidly increases. If the N composition ratio exceeds 50%, the formed anodic oxide film becomes a porous film, and the electrical characteristics such as withstand voltage decrease. Therefore, it is desirable that the N composition ratio is 25% or more and 50% or less.

FIG. 3 shows the disconnection rate of an Al wiring when another Al wiring is formed on the upper layer of the laminated wiring having the structure shown in FIG.
This is a study conducted by changing the N composition of the Ta _1-x N _x electrode forming the laminated wiring. Here, the laminated wiring was formed by forming an Al film having a film thickness of 300 nm on a Ta _1-x N _x film having a film thickness of 100 nm, patterning this, and then anodic oxidation. Anodization is A
The l ₂ O ₃ film was formed to have a film thickness of 200 nm. The step formed by the laminated wiring is about 370 nm. The film thickness of the upper Al electrode was 20 nm.

When the N composition is 0, the disconnection rate is as large as 5% or more. The disconnection rate decreases as the N composition increases, and when the N composition ratio is 25% or more, the disconnection rate becomes almost 0, and the disconnection prevention effect by the step relaxation according to the present invention is clear.

Example 2 FIG. 4 is a schematic sectional view of a unit pixel of a liquid crystal display device of the present invention.

A Ta _1-x N _x electrode (X =
0.45) 100 and an Al electrode 11 are formed as a scanning signal electrode, and the Ta ₂ O _x N _y film 20 is formed on the surface and the side surface thereof.
1 and an Al ₂ O ₃ film 21. The SiN film 22, the a-Si: H film 30, and the
An n-type a-Si: H film 31 is formed, and further n-type a-S
The video signal electrode 14 and the source electrode 15 are formed on the i: 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 1 are connected.
6 constitutes an additional capacity. Further, the whole of them is covered with a protective SiN film 23.

According to this embodiment, since the growth rate of the Ta ₂ O _x N _y film is large, the laminated scanning signal electrodes 100 and 11 are formed.
Since the step difference due to the above can be alleviated, the disconnection defect of the video signal electrode 14 formed in the upper layer can be prevented. Further, since the Ta ₂ O _x N _y film 201 and the Al ₂ O ₃ film 21 having good insulating properties can be used as the interlayer insulating film and the gate insulating film, a short circuit defect between the video signal electrode 14 and the scanning signal electrode can be prevented. it can. Further, by using Al having a low wiring resistance for the scanning signal electrode, the delay of the scanning signal can be prevented and the display device can be increased in size and definition.

FIG. 5 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 Al ₂
The Ta _1-x N _x electrode 100 is covered with an O ₃ film 2 and the Ta _1-x N _x electrode 100 is Al ₂
The O ₃ film 21 is extended to the outside to form an external connection terminal. Further, the Ta _1-x N _x electrode 100 was covered with the ITO electrode 13. In this embodiment, the contact resistance for Ta _1-x N _x and ITO barrier layer formed on the Ta _1-x N _x and ITO surface by reaction is not completely insulating property, for example, a combination of Al and ITO It is much smaller than the case. In addition, Ta _1-x N _x and ITO hardly increase the contact resistance due to heat treatment, so that an extremely stable connection terminal can be obtained.

Not limited to Ta-N alloy, Nb-N alloy, Ta-Nb-N alloy, Ta-Ti-N alloy, Ta-W.
Even if a metal nitride such as -N alloy is used, the reaction between the metal and ITO can be further suppressed, so that the contact resistance can be made extremely small.

Embodiment 3 FIG. 6 is a schematic sectional view of a unit pixel of a liquid crystal display device according to another embodiment of the present invention.

A scanning signal electrode composed of a Ta electrode 10 and an Al electrode 11 is formed on the glass substrate 1, and the surface and side surface of these are covered with a Ta ₂ O ₅ film 20 and an Al ₂ O ₃ film 21. Here, the width of the Ta electrode 10 is the Al electrode 11
It is formed to be wider than. The SiN film 22, the a-Si: H film 30, the n-type a-S are formed on the scanning signal electrode.
The i: H film 31 is formed, and the n-type a-Si: H film 3 is further formed.
A video signal electrode 14 and a source electrode 15 are formed on the pixel electrode 1, and a pixel electrode 13 made of an ITO film is formed on the source electrode.
Are connected. 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. In addition, all of these are protected by SiN
It is covered with a film 23.

Also in this embodiment, as in the previous embodiment, the step difference due to the laminated scanning signal electrodes 10 and 11 has a two-step step shape, so that the disconnection defect of the video signal electrode 14 formed in the upper layer can be prevented. .

7 to 11 are sectional views showing the manufacturing process of the above embodiment. The right side portion of the drawing shows a cross section of the external connection terminal portion of the scanning signal electrode.

On the glass substrate 1, Ta _1-x N _x electrodes (X =
0.45) 100, an Al film 11 is continuously deposited by sputtering and patterned into a predetermined shape by using a photolithography technique (FIG. 7). At this time, hydrogen bromide (HB
The patterning was performed by the reactive ion etching method using a mixed gas plasma of r) and boron trichloride (BCl ₃ ). Since bromine is extremely sublimable, it has an effect of preventing Al corrosion due to residual halogen gas generated when the substrate is taken out into the atmosphere after etching.

Further, by selecting etching conditions such that the etching is not completely anisotropic, side etching occurs in Al having a high etching rate. As a result, a stepwise cross-sectional shape as shown in FIG. 7 can be formed by one mask process. As a result, the cross section after anodic oxidation is completely terraced, and the steps are more relaxed. Next, a Ta _1-x N _x electrode (X = 0.45) and a Ta ₂ O _x N _y film 201 and an Al ₂ O ₃ film 2 are formed on the surface and side surfaces of the Al film by anodization.
1 (FIG. 8). Next, the Al film 11 at the scanning signal electrode terminal portion is removed by etching by a reactive ion etching method using a mixed gas plasma of hydrogen bromide (HBr) and boron trichloride (BCl ₃ ) with the Al ₂ O ₃ film 21 as a mask. Then, the Ta _1-x N _x electrode 100 is exposed. Then ITO
The film is deposited by sputtering and patterned by using the photolithography technique to form the pixel electrode 13 and the terminal Ta.
Forming a protective film 131 of the _1-x N x (Fig. 9). Next, a gate SiN film 22, an a-Si: H film 30, and an n-type a-Si: H film 31 are deposited by plasma CVD, and a-Si: H is deposited.
The film 30 and the n-type a-Si: H film 31 are patterned into a predetermined shape, and then the gate SiN film 22 on the pixel electrode 13 and the terminal electrode is removed (FIG. 10). Next, an Al film is deposited by sputtering and patterned into a predetermined shape to obtain the video signal electrode 14, the source electrode 15 and the capacitor electrode 16. Finally protected by plasma CVD S
The iN film 23 is formed to complete the thin film semiconductor device (see FIG. 1).
1).

According to this embodiment, since the laminated scanning signal electrode having the stepwise cross-sectional shape can be formed by one mask process, it is possible to prevent disconnection of the upper layer video signal electrode and reduce the number of processes. effective. Further, according to this embodiment, since Ta _1-x N _x having high corrosion resistance can be used for the external connection terminal, high reliability can be secured. Further, since the Ta _1-x N _x 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, is not required, so the number of steps is reduced. There is an effect that can be done. Further, when the Ta _1-x N _x electrode of the external connection terminal portion is exposed, side etching of the Al electrode 11 can be prevented by using the reactive ion etching method, so that an overhang of the Al ₂ O ₃ film 21 is formed. There is nothing to be done. Further, at this time, by using a mixed gas of hydrogen bromide (HBr) and boron trichloride (BCl ₃ ) as an etching gas, a large etching selection ratio of Al and Ta _1-x N _x can be obtained, so that the etching work margin can be increased. Is increased and the yield is improved.

12 to 13 are sectional views showing another manufacturing process of the above embodiment.

On the glass substrate 1, Ta _1-x N _x film 100, A
1 film 11 is continuously deposited by sputtering, and a resist pattern having a predetermined shape is formed by using a photolithography technique.
300 is formed, and the Al electrode 11 is patterned by the usual wet etching method using mixed acid (FIG. 12).
Next, using the same resist pattern 300, Ta is formed by a reactive ion etching method using a mixed gas plasma of hydrogen bromide (HBr) and boron trichloride (BCl ₃ ).
_{Pattern the 1-x Nx} electrodes (FIG. 13). Hereinafter, after the step of forming the Ta ₂ O _x N _y film 201 and the Al ₂ O ₃ film 21 on the surface and the side surface of the Ta _1-x Nx film 100 and the Al film 11 by the anodic oxidation method, the same manufacturing steps as described above are performed. carry out. According to this manufacturing method, since the Al electrode 11 is processed by the wet etching method, side etching of several μm occurs in the Al electrode. Further, since the Ta _1-x N _x electrode is processed by anisotropic etching by reactive ion etching using the resist formed first as a mask, side etching hardly occurs. Therefore, in the processed shape of the laminated electrode after etching, the width of the Ta1-xNx electrode is wider than that of the Al electrode, and a stepwise cross-sectional shape can be realized by anodizing this.

In the above examples, the nitrogen composition of the lower layer metal is T
Although a _1-x N _x (X = 0.45) is used, the desired effect can be obtained if the nitrogen composition is not in this composition range and X is in the range of 0.25 to 0.5. The nitrogen composition of the lower layer metal may not be uniform in the film, but may have a minimum composition at the interface with the upper Al electrode and have a composition gradient such that it gradually increases toward the interface with the substrate. By doing so, the volume expansion during the growth of the oxide film becomes larger as it gets closer to the surface of the substrate, so that an extremely gentle step can be formed. For a film having such a composition gradient, for example, a metal such as pure Ta is used as a sputtering target and a mixed gas of Ar and N ₂ is used as a sputtering gas, and the N ₂ concentration in the sputtering gas is gradually decreased with the progress of film formation. It can be realized by doing. In this case, the insulating characteristics of the anodic oxide film can be kept good by adjusting the conditions so that the maximum value of N composition does not exceed 50 atomic%.

In the above example, Ta is used as the scanning signal electrode.
_{Although 1-x} N _x and Al have been described, the present invention is not limited to this combination, but W, Nb instead of Ta, or an alloy containing them, such as TaN, NbN, Ta-Nb-.
The same applies when N, Ta-Ti-N or the like is used. Further, not only pure Al but also Al-Pd, Al-Ta, Al-
An alloy such as Ti-Ta or Al-Si may be used.

FIG. 14 shows a TF according to the liquid crystal display device of the present invention.
It is an equivalent circuit of a T-board. On the glass substrate 1, a plurality of scanning signal electrodes 100/11, a plurality of video signal electrodes 14 orthogonal to the scanning signal electrodes 100/11, TFTs connected to these electrodes, T
It is composed of a liquid crystal capacitance connected to the FT and an additional capacitance. A terminal 1 for connecting an external member is provided at either end of the scanning signal electrode 100/11 or the video signal electrode 14.
40 is provided. The image is displayed by the scanning signal electrode 10
A pulse signal is sequentially applied to 0/11 to turn on the TFTs for one row, and an image signal is applied from the video signal electrode to the liquid crystal layer during that time. This operation is repeated for each line to display the image.

FIG. 15 is an equivalent circuit of another TFT substrate according to the liquid crystal display device of the present invention. A plurality of scanning signal electrodes 100/11 on the glass substrate 1, a plurality of video signal electrodes 14 orthogonal to the scanning signal electrodes 100/11, and TFTs connected to these electrodes.
And a liquid crystal capacitance connected to the TFT and an additional capacitance are the same as in the previous example, but in this embodiment, T
The scanning signal circuit 220 and the video signal circuit 210 for driving the FT are configured by using TFTs on the glass substrate. By thus integrating the drive circuit on the glass substrate, the number of external parts can be significantly reduced, and thus the cost can be significantly reduced. It goes without saying that the wiring material of the present invention can be similarly applied to the case where the number of such external connection terminals is small.

In the above-mentioned embodiments, an example using an inverted staggered type thin film transistor has been described, but the wiring material of the present invention is not limited to this, and the same applies to a thin film transistor having a staggered type or coplanar type electrode structure. It can be applied and the same effect can be obtained.

FIG. 16 is a schematic sectional view of a liquid crystal display device constituted by the thin film semiconductor device of the present invention. Liquid crystal layer 506
On the lower glass substrate 1 with reference to
And the video signal electrodes 14 are formed in a matrix, and the pixel electrodes 13 made of ITO are driven through the TFTs formed in the vicinity of their intersections. The counter electrode 5 made of ITO is formed on the counter glass substrate 508 that faces the liquid crystal layer 506.
10, a color filter 507, a color filter protective film 511, and a light shielding film 512 forming a black matrix pattern for light shielding. The central portion of FIG. 16 is a cross section of one pixel portion, and the left is a pair of glass substrates 1 and 5.
08 shows the cross section of the left edge portion of the glass substrate where the external lead terminal is present, and the right side shows the cross section of the right edge portion of the pair of glass substrates 1 and 508 where the external lead terminal does not exist. The sealing material SL shown on each of the left side and the right side of FIG. 16 is configured to seal the liquid crystal layer 506, and extends along the entire edges of the glass substrates 1 and 508 excluding the liquid crystal sealing port (not shown). Has been formed. The sealing agent is made of, for example, an epoxy resin. The counter electrode 510 on the counter glass substrate 508 side is connected to the external extraction wiring formed on the glass substrate 1 by the silver paste material SIL at at least one location. This external connection wiring is the scanning signal wiring 1
0, the source electrode 15, and the video signal wiring 14 are formed in the same manufacturing process. Alignment film ORI1, ORI2
Pixel electrode 13, protective film 23, color filter protective film 5
11, each layer of the gate SiN film 21 is a sealing material S
It is formed inside L. The polarizing plates 505 are formed on the outer surfaces of the pair of glass substrates 1 and 508, respectively.

The liquid crystal layer 506 is enclosed between the lower alignment film ORI1 and the upper alignment film ORI2 that set the orientation of the liquid crystal molecules, and is sealed by the sealing material SL. The lower alignment film ORI1 is formed on the protective film 23 on the glass substrate 1 side. On the inner surface of the counter glass substrate 508, a light shielding film 512, a color filter 507, a color filter protective film 511, a counter electrode 510 and an upper alignment film ORI.
2 are sequentially stacked. This liquid crystal display device is assembled by separately forming layers on the glass substrate 1 side and the counter glass substrate 508 side, then stacking the upper and lower glass substrates 1 and 508 and enclosing the liquid crystal 506 between them. Transmitting light from the backlight BL to the pixel electrode 1
A TFT drive type color liquid crystal display device is constructed by adjusting the three parts.

Since the liquid crystal display device of the present invention can use the scanning signal electrode made of the laminated wiring material containing low resistance Al, it is suitable for increasing the size and increasing the definition. Further, since the disconnection failure of the upper wiring which occurs due to the use of the laminated wiring material can be prevented, the yield is improved. In addition, since it can be manufactured by a simple manufacturing process, it is possible to significantly reduce the cost and provide an inexpensive liquid crystal display device.

[0063]

As described above, according to the present invention, by using the laminated wiring material, the scanning signal electrode having a low resistance and the external connection terminal having a high corrosion resistance can be formed in a minimum photolithography process. realizable. At the same time, it is possible to prevent the disconnection failure of the upper wiring that occurs when the laminated wiring material is adopted, so that the yield is improved. Therefore, the liquid crystal display device can be increased in size, increased in definition, and reduced in cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a laminated wiring used in the present invention.

FIG. 2 is a diagram showing characteristics of a laminated wiring used in the present invention.

FIG. 3 is a diagram showing an effect of a laminated wiring used in the present invention.

FIG. 4 is a pixel cross-sectional view of the first liquid crystal display device according to the present invention.

FIG. 5 is a cross-sectional view of an external connection terminal of a scanning signal electrode of the first liquid crystal display device according to the present invention.

FIG. 6 is a pixel cross-sectional view of a second liquid crystal display device used in the present invention.

FIG. 7 is a cross-sectional view showing a manufacturing process of a liquid crystal display device according to the present invention.

FIG. 8 is a cross-sectional view showing a manufacturing process of a liquid crystal display device according to the present invention.

FIG. 9 is a cross-sectional view showing a manufacturing process of a liquid crystal display device according to the present invention.

FIG. 10 is a cross-sectional view showing a manufacturing process of a liquid crystal display device according to the present invention.

FIG. 11 is a cross-sectional view showing the manufacturing process of the liquid crystal display device according to the present invention.

FIG. 12 is a cross-sectional view showing another manufacturing process of the liquid crystal display device according to the present invention.

FIG. 13 is a cross-sectional view showing another manufacturing process of the liquid crystal display device according to the present invention.

FIG. 14 is an equivalent circuit diagram of a liquid crystal display device according to the present invention.

FIG. 15 is an equivalent circuit diagram of another liquid crystal display device according to the present invention.

FIG. 16 is a cell cross-sectional view of a liquid crystal display device according to the present invention.

FIG. 17 is an explanatory diagram of a conventional technique.

FIG. 18 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

1 ... Glass substrate, 10 ... Ta electrode, 11 ... Al electrode, 1
3 ... Pixel electrode, 14 ... Video signal electrode, 15 ... Source electrode, 16 ... Capacitance electrode, 20 ... Ta ₂ O ₅ film, 21 ... Al ₂
O ₃ film, 22 ... Gate SiN film, 23 ... Protective SiN film,
30 ... a-Si: H film, 31 ... n-type a-Si: H film, 1
00 ... TaN electrode, 110 ... Cr electrode, 131 ... Terminal part protective film, 140 ... External connection terminal, 201 ... Ta ₂ O _x N
_y film, 210 ... Video signal drive circuit, 220 ... Scan signal drive circuit, 505 ... Polarizing plate, 506 ... Liquid crystal layer, 507 ... Color filter, 508 ... Counter glass substrate, 510 ... Counter electrode, 511 ... Color filter protective film, 512 ... Shading film, ORI1 ... Upper alignment film, ORI2 ... Lower alignment film,
SL ... Sealing material, SIL ... Silver paste material, BL ... Backlight.

Claims (12)

[Claims] 1. A scanning signal electrode formed on an insulating substrate, a video signal electrode formed so as to intersect with the scanning signal electrode, and a thin film transistor formed near the intersection between the scanning signal electrode and the video signal electrode. In the liquid crystal display device having an active matrix substrate including pixel electrodes connected to the thin film transistors and an external driving circuit for driving the active matrix substrate, the liquid crystal display device having a function of driving liquid crystal by the pixel electrodes, the scanning signal electrodes Among the video signal electrodes, at least one of the signal electrodes formed in a lower layer is formed in a lower layer of the first conductive film and a first conductive film made of Al or an alloy film containing Al as a main component. And at least two layers including a second conductive film, and the second conductive film is formed when the self-oxidized film grows more than the first conductive film. The liquid crystal display device, characterized in that the volume expansion rate is composed of a material having large. 2. A scanning signal electrode formed on an insulating substrate, a video signal electrode formed so as to intersect with the scanning signal electrode, and a thin film transistor formed near the intersection between the scanning signal electrode and the video signal electrode. In the liquid crystal display device having an active matrix substrate including pixel electrodes connected to the thin film transistors and an external driving circuit for driving the active matrix substrate, the liquid crystal display device having a function of driving liquid crystal by the pixel electrodes, the scanning signal electrodes Among the video signal electrodes, at least one of the signal electrodes formed in a lower layer is formed in a lower layer of the first conductive film and a first conductive film made of Al or an alloy film containing Al as a main component. TaN, NbN, Ta-Nb-N alloy, Ta
1 selected from -Ti-N alloy and Ta-W-N alloy
And a composition ratio of N contained in the second conductive film is 25 atomic% or more and 50 atomic% or less. Liquid crystal display device. 3. The liquid crystal display device according to claim 1, wherein
A liquid crystal display device, wherein the surfaces and side surfaces of the first and second conductive films are covered with a self-oxidation film of a material forming the first and second conductive films, respectively. 4. The liquid crystal display device according to claim 1,
A liquid crystal display device, wherein the scanning signal electrode is used as a gate electrode of the thin film transistor. 5. The liquid crystal display device according to claim 1, wherein
The liquid crystal display device according to claim 1, wherein the first conductive film is present only at a position separated by 0.1 cm or more from one end of the scanning signal electrode. 6. The liquid crystal display device according to claim 1,
A connection terminal between the active matrix substrate and the external drive circuit is formed of the second conductive film or the second conductive film and a transparent conductive film formed on the second conductive film. Liquid crystal display device. 7. A method of manufacturing a liquid crystal display device, comprising the following steps. (1) A step of sequentially laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component on an insulating substrate in a vacuum. (2) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film. (3) A step of continuously patterning the first conductive film and the second conductive film using the photoresist pattern as a mask by a dry etching method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas. (4) A step of forming self-oxidized films of these conductive films on a part of the surfaces and side surfaces of the patterned first conductive film and second patterned conductive film. 8. A method of manufacturing a liquid crystal display device, comprising the following steps. (1) A step of sequentially laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component on an insulating substrate in a vacuum. (2) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film. (3) A step of patterning only the first conductive film by a wet etching method using the photoresist pattern as a mask. (4) A step of patterning the second conductive film by a dry etching method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas, using the photoresist pattern as a mask. (5) A step of forming a self-oxidized film of these conductive films on a part of the surface and side surfaces of the patterned first conductive film and second patterned conductive film. 9. A method of manufacturing a liquid crystal display device, which comprises the following steps. (1) A step of sequentially laminating a second conductive film and a first conductive film made of Al or an alloy film containing Al as a main component on an insulating substrate in a vacuum. (2) A step of forming a photoresist pattern on the laminated film of the second conductive film and the first conductive film. (3) A step of continuously patterning the first conductive film and the second conductive film using the photoresist pattern as a mask by a dry etching method using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas. (4) A step of forming self-oxidized films of these conductive films on a part of the surfaces and side surfaces of the patterned first conductive film and second patterned conductive film. (5) By using the self-oxidizing film as a mask, only the portion of the first conductive film which is not covered with the self-oxidizing film is dry-etched using a mixed gas plasma containing at least a halogen gas or a hydrogen halide gas. Step of removing by etching. 10. The method for manufacturing a liquid crystal display device according to claim 7, 8 or 9, wherein boron trichloride gas is used as a gas for patterning the first conductive film or the second conductive film by a dry etching method. A method of manufacturing a liquid crystal display device, which comprises using a mixed gas of hydrogen bromide gas. 11. The method of manufacturing a liquid crystal display device according to claim 9, wherein only the first conductive film in a portion not covered with the self-oxidation film is removed by a dry etching method using the self-oxidation film as a mask. A method for manufacturing a liquid crystal display device, characterized in that a mixed gas of boron trichloride gas and hydrogen bromide gas is used as a gas for the purpose. 12. The liquid crystal display device according to claim 2,
The nitrogen concentration in the second conductive film is the lowest near the interface with the first conductive film, and has a distribution that decreases as the distance from the interface with the first conductive film decreases. Display device.