JP3208646B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and a method for manufacturing the same. More specifically, the Al-based alloy film is etched with a phosphoric acid-based etchant containing no hydrofluoric acid,
The present invention relates to a liquid crystal display device capable of forming a gate wiring and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, demand for a liquid crystal display device comprising a thin film transistor has been rapidly increasing, and its size and definition have been increasing. Along with this, it is important to reduce the resistance of the gate wiring in order to reduce the luminance difference on the screen.
In many cases, an alloy mainly composed of is used.
In this case, pure Al has problems such as a decrease in reliability due to hillocks. Here, the hillock is a crystal grain that has grown into a projection shape due to heat or the like. The hillock is a phenomenon often seen in pure Al. In order to avoid this hillock, an Al-based alloy using an additive such as Si or Cu instead of pure Al is generally used.

On the other hand, when etching these pure Al and Al-based alloys, a phosphoric acid-based wet etchant is generally used. However, the phosphoric acid-based wet etching solution has no problem with respect to etching of pure Al, but has a problem with etching of an Al-based alloy to which Si or Cu is added, in that a residue of the additive remains. are doing. In response to such a problem, in etching an Al-based alloy to which Si or Cu is added, as a wet etching solution that does not generate a residue, there is a wet etching solution in which hydrofluoric acid is added to phosphoric acid. The wet etching solution is not preferable because it also erodes the glass of the substrate. In this way, no alloy or wet etchant can solve all the problems,
For example, with a phosphoric acid-based etchant that does not contain hydrofluoric acid,
Performing etching of an Al-based alloy to which Si, Cu or the like is added without generating a residue is the most important technical problem in manufacturing a thin film transistor liquid crystal display device.

Next, a gate electrode of a conventional liquid crystal display device will be described with reference to FIG. In FIG. 5, 11 is a transparent insulating substrate, 13 is an Al—Si alloy film,
Reference numeral 4 denotes a resist pattern, and reference numeral 17 denotes a pure Al film.
As a method for solving the above-mentioned problem, Japanese Patent Application Laid-Open No.
The methods described in Japanese Patent Application Laid-Open No. 21455 and Japanese Patent Application Laid-Open No. 6-181208 have been proposed. JP-A-61-12145
No. 5 describes a method of removing a residue by providing a second Al-Cu alloy film having a low Cu content below the Al-Cu alloy film. JP-A-6-181
No. 208, a pure Al film 17 is provided as a lower layer film of the Al-Si alloy film 13 (see FIG. 5A), a resist pattern 14 is formed (see FIG. 5B), and the Al-Si The alloy film 13 and the pure Al film 17 are etched (FIG. 5).
(See (c)) to obtain a residue-free liquid crystal display device (see FIG. 5D). In any case, the film in the lower layer of the Al-based alloy film contains little or no additive, so that no etching residue is generated, and the film in the upper layer of the Al-based alloy film contains a relatively large amount of the additive. Can be suppressed. These methods are effective as etching methods that do not generate residues, but still have two problems. One is that an Al film having a low additive concentration is exposed on the side surface of the wiring. Therefore, side hillocks that grow in the lateral direction cannot be suppressed. On the other hand, in order to suppress the hillock growth of the lower film, the upper film needs to have a certain thickness or more. For this reason, it is difficult to control the conditions at the time of forming the upper layer film, and since the total thickness of the upper layer and the lower layer is increased, the coverage of the film provided further above the upper layer film is also difficult. Due to such a problem, the gate wiring formed by the above-described method lacks reliability and stability.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a liquid crystal display device capable of forming a gate electrode by etching an Al-based alloy film with a phosphoric acid-based etching solution containing no hydrofluoric acid, and a method of manufacturing the same. The purpose is to do.

[0006]

A liquid crystal display device according to the present invention is an array substrate comprising a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at the intersection of the two wirings. And an opposing substrate disposed to face a part of the array substrate; and a liquid crystal sandwiched between the array substrate and the opposing substrate, wherein the gate wiring is an Al-based alloy made of an alloy containing Al. A film is formed, and a lower layer film is provided as a dummy film below the Al-based alloy film.

It is preferable that the lower layer film comprises any one of the following (1) to (4) from the viewpoint of adhesion to a transparent insulating substrate, corrosion resistance after pattern formation, and the like.

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 The present invention provides a liquid crystal display device comprising: a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at an intersection of the two wirings;
An opposing substrate disposed to face a part of the array substrate, and a liquid crystal sandwiched between the array substrate and the opposing substrate, wherein an Al-based alloy film of an alloy containing Al is used as the gate wiring. After forming a lower layer film as a dummy film below the Al-based alloy film, etching the lower layer film, and further forming a protective film on the upper layer of the Al-based alloy film, Is formed by etching.

It is preferable that the lower layer film is composed of any one of the following (1) to (4) in terms of adhesion to a transparent insulating substrate, corrosion resistance after pattern formation, and the like.

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 The present invention provides a liquid crystal display device comprising: a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at an intersection of the two wirings;
An opposing substrate disposed to face a part of the array substrate, and a liquid crystal sandwiched between the array substrate and the opposing substrate, wherein an Al-based alloy film of an alloy containing Al is used as the gate wiring. After forming a lower layer film as a dummy film below the Al-based alloy film, etching the lower layer film halfway, and further forming a protective film above the Al-based alloy film, The protective film is formed by etching the lower layer film and the protective film which have been partially etched.

It is preferable that the lower layer film is composed of any one of the following (1) to (4) in terms of adhesion to a transparent insulating substrate, corrosion resistance after pattern formation, and the like.

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 Insulator of Resin-Based Organic Material A method for manufacturing a liquid crystal display device of the present invention is directed to an array substrate including a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at an intersection of the two wirings. And a counter substrate disposed to face a part of the array substrate, and a liquid crystal display device comprising a liquid crystal sandwiched between the array substrate and the counter substrate. Successively forming an Al-based alloy film and an underlayer film as a dummy film provided below the Al-based alloy film, and using the same resist pattern for the two films, It continues to be characterized by comprising the step of etching.

[0013] A method of manufacturing a liquid crystal display device according to the present invention is directed to an array substrate comprising a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at the intersection of the two wirings. A method for manufacturing a liquid crystal display device, comprising: a counter substrate disposed to face a part of a substrate; and a liquid crystal sandwiched between the array substrate and the counter substrate, wherein an Al-based alloy as the gate wiring is provided. A step of continuously forming a film and a lower layer film as a dummy film provided below the Al-based alloy film, a step of etching the Al-based alloy film using a resist pattern, and removing the resist pattern And etching the lower layer film using the pattern of the Al-based alloy film.

[0014] A method of manufacturing a liquid crystal display device according to the present invention is directed to a method for manufacturing a liquid crystal display device, comprising: an array substrate comprising a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at an intersection of the two wirings; A method for manufacturing a liquid crystal display device, comprising: a counter substrate disposed to face a part of a substrate; and a liquid crystal sandwiched between the array substrate and the counter substrate, wherein an Al-based alloy as the gate wiring is provided. A step of continuously forming a film and a lower film as a dummy film provided below the Al-based alloy film, a step of etching the lower-layer film, and forming a protective film on the upper layer of the Al-based alloy film. It is characterized by comprising a step of forming a film and a step of etching the protective film.

A method of manufacturing a liquid crystal display device according to the present invention is directed to a method of manufacturing a liquid crystal display device, comprising: an array substrate having a transparent insulating substrate provided with a gate wiring, a source wiring, and a switching element formed at an intersection of the two wirings; A method for manufacturing a liquid crystal display device, comprising: a counter substrate disposed to face a part of a substrate; and a liquid crystal sandwiched between the array substrate and the counter substrate, wherein an Al-based alloy as the gate wiring is provided. Successively forming a film and a lower film as a dummy film provided below the Al-based alloy film, performing a halfway etching of the lower film, and forming a protective film on the upper layer of the Al-based alloy film. And a step of simultaneously or continuously etching the underlayer film partially etched and the protective film.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a liquid crystal display device of the present invention and a method for manufacturing the same will be described with reference to the drawings. 1, 2, 3, and 4 are process cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention. 1 to 4, the same elements are denoted by the same reference numerals.

Example 1 In FIG. 1, 1 is a transparent insulating substrate, 2 is a lower film as a dummy film, 3 is an Al-based alloy film, and 4
Is a resist pattern. As shown in FIG. 1A, the liquid crystal display device of the present invention is manufactured on a surface of a transparent insulating substrate 1 made of glass or the like by, for example, a sputtering method, a vapor deposition method, or a CVD (chemical vapor deposition) method. A lower film (dummy film) 2 is formed, and an Al-based alloy film 3 is further formed sequentially. The thickness of the lower layer film 2 is not particularly limited as long as it is within a limit at which the film forming apparatus can form a uniform film, but according to the current film forming apparatus, the film thickness may be 300 mm or more. The properties required for the material of the lower layer film 2 include that the additive of the Al-based alloy film is hardly diffused, that there is no hillock, and that there is no grain growth by a subsequent heat treatment. It consists of any one of the following (1) to (4).

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 In the present embodiment, since the lower layer film 2 is etched by a wet etching method as described later, a metal or an alloy is often used as the lower layer film, but is not limited thereto.

In this embodiment, for example, a Cr film having a thickness of 500 ° formed by a sputtering method is used as the lower film 2. The thickness of the Al-based alloy film 3 can be reduced within a controllable range of the film forming apparatus. The property required for the material of the Al-based alloy film 3 is that hillocks are hardly generated. In general,
An Al-Si alloy film or an Al-Cu alloy film is used. Here, for example, a film containing 1 wt% of Si and having a film thickness of 1
An Al-Si alloy film formed by sputtering with a thickness of 000 ° is used as the Al-based alloy film 3.

Next, as shown in FIG. 1B, a photolithography technique for forming a resist in a desired shape on the Al-based alloy film 3 by a normal resist coating and exposing method (hereinafter simply referred to as a "photolithography technique"). Patterning is performed by “photolithography technology” to form a resist pattern 4 on the Al-based alloy film 3. As shown in FIG. 1C, using the resist pattern 4 as a mask, the Al-based alloy film 3 is etched with an etching solution composed of, for example, phosphoric acid: nitric acid: acetic acid: water = 15: 1: 3: 1. On this occasion,
Residues of the additives of the Al-based alloy film 3 remain on the lower film 2. However, the residue of the additive of the Al-based alloy film 3 is completely removed by subsequently etching the lower layer film 2. At this time, the lower film 2 is etched by a wet etching method in the same manner as the etching for the Al-based alloy film 3. In the wet etching method, since the etching proceeds isotropically, the edge of the Al-based alloy film 3 located below the resist pattern 4 and the edge of the lower layer film 2 located below the resist pattern 4 are etched. A
Both edges of the l-based alloy film 3 and the lower film 2 are intruded by several μm from the edges of the resist pattern 4 (see FIG. 1C). Finally, the resist pattern 4
To remove Al, as shown in FIG.
A gate wiring is formed by the base alloy film. Thereafter, a source wiring, a display electrode, a thin film transistor, a drain wiring, and the like are formed on the transparent insulating substrate 1 by an ordinary method of manufacturing a liquid crystal display device, and an array substrate is formed. A counter substrate made of a transparent insulating substrate or the like is provided, and a liquid crystal is sandwiched between the array substrate and the counter substrate to complete a liquid crystal display device.

Embodiment 2 In Embodiment 1 described above, a lower layer film (dummy film) 2, an Al-based alloy film 3, and a resist pattern 4 are sequentially formed on the surface of an insulating substrate 1, and the Al pattern is formed using the resist pattern 4 as a mask. The system alloy film 3 and the lower layer film 2 are sequentially etched, and finally, the resist pattern 4 is removed. In this embodiment, the lower layer film is etched by a highly anisotropic dry etching method using an Al-based alloy film as a mask instead of the resist pattern. When the lower layer film 2 is etched by a highly anisotropic dry etching method using the resist pattern 4 as a mask, the portion where the resist pattern 4 is formed is not etched. The bottom residue (Fig. 2
There is a problem that the residue (5a in (c)) cannot be removed. The residue under the resist pattern 4 means that when the Al-based alloy film 3 is wet-etched, the etching extends to the portion where the resist pattern 4 is formed and the Al-based alloy film 3 located under the resist pattern 4. This is the residue remaining after a part of the residue was removed.

In order to solve the above-mentioned problem, a method is conceivable in which the resist pattern 4 is removed first, and then the lower layer film 2 is etched by dry etching using the Al-based alloy film 3 as a mask. In FIG. 2, 1 is a transparent insulating substrate, 2 is a lower layer film as a dummy film, 3 is an Al-based alloy film, 4 is a resist pattern, 5
And 5a are residues of additives. The lower film 2
The properties required for the material (1) include that the additive of the Al-based alloy film is hardly diffused, that there is no hillock, and that there is no grain growth due to the subsequent heat treatment. It consists of any one of (4).

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 In the present embodiment, since the lower film 2 is etched by a dry etching method as described later, a nitride is often used as the lower film, but is not limited thereto.

In this embodiment, the lower layer film 2, the Al-based alloy film 3, and the resist pattern 4 are formed on the surface of the insulating substrate 1.
Are sequentially formed (see FIGS. 2A and 2B), and the Al-based alloy film 3 is etched using the resist pattern 4 as a mask (see FIG. 2C).
(See FIG. 2D). Finally, the lower film 2 is etched using the Al-based alloy film 3 as a mask to remove all the residue of the additive on the lower film 2 (FIG. 2).
(E)).

Embodiment 3 In Embodiments 1 and 2 described above, it is shown that the residue on the lower layer film 2 can be removed. However, the Al-based alloy film used as the gate wiring,
Generally, it is necessary to cover the surface with a corrosion resistant metal to prevent corrosion.

This embodiment is an example in which a residue on the lower layer film 2 can be removed and a protective film for preventing corrosion of the Al-based alloy film is formed in the same manner as in the first and second embodiments.

In FIG. 3, 1 is a transparent insulating substrate, 2 is a lower layer film as a dummy film, 3 is an Al-based alloy film, 4 is a resist pattern, and 5 is a residue of an additive. Reference numeral 6 denotes a protective film made of a corrosion-resistant metal.
First, using the same material as the protective film 6 formed after the material of the lower film (dummy film) 2, the gate wiring of the liquid crystal display device of the present invention is formed by the following method. FIG. 3 (a)
As shown in (1), an Al-based alloy film 3 and a lower film 2 are formed. Next, a resist pattern 4 is formed by photolithography (see FIG. 3B), the Al-based alloy film 3 is etched (see FIG. 3C), and then the lower film 2 is etched (see FIG. d)), and the resist pattern 4 is removed (see FIG. 3E). At this time, the etching of the Al-based alloy film 3 and the lower layer film 2 is performed by a wet etching method. Subsequently, a protective film 6 is formed so as to cover the transparent insulating substrate 1 and the Al-based alloy film 3 (FIG. 3).
(See (f)), and finally, the Al-based alloy film 3 is etched.
(See FIG. 3D) to form a gate wiring. At this time, the etching of the protective film 6 is performed by a wet etching method.

The protective film 6 and the lower film 2 are made of, for example, any one of the following (1) to (4).

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 Example 4) Resin-based organic insulator Example 4 In Example 3 described above, the lower film 2 is etched by a wet etching method to remove residues on the lower film 2. However, in general, when the etching of the lower layer film 2 is performed by wet etching, the wet etching is performed in a direction parallel to and perpendicular to the surface of the lower layer film 2. 3
Is also etched on the side surface of the Al-based alloy film 3 and a recess is generally formed on the side surface of the Al-based alloy film 3.

In this embodiment, the residue on the lower film 2 can be removed in the same manner as in the third embodiment, and further, the corrosion of the Al-based alloy film can be prevented, and the residue of the additive is removed by etching the lower film 2. This is an example in which the process is terminated at the time of the formation and the size of the concave portion formed on the side surface of the Al-based alloy film 3 is reduced as much as possible.

In FIG. 4, 1 is a transparent insulating substrate, 2 is a lower film as a dummy film, 3 is an Al-based alloy film, 4 is a resist pattern, and 5 is a residue of an additive. Reference numeral 6 denotes a protective film made of a corrosion-resistant metal.
First, using the same material as the protective film 6 formed after the material of the lower film (dummy film) 2, the gate wiring of the liquid crystal display device of the present invention is formed by the following method. FIG. 4 (a)
As shown in (1), an Al-based alloy film 3 and a lower film 2 are formed. Next, a resist pattern 4 is formed by photolithography (see FIG. 4B), the Al alloy film 3 is etched (see FIG. 4C), and then the lower film 2 is etched (see FIG. d)), and the resist pattern 4 is removed (see FIG. 4E). At this time, the etching of the Al-based alloy film 3 and the lower layer film 2 is performed by a wet etching method. Further, the etching of the lower film 2 is terminated when the residue on the lower film 2 can be removed. Subsequently, a protective film 6 is formed so as to cover the lower layer film 2 and the Al-based alloy film 3 (see FIG. 4F). Finally, the protective film 6 is etched so as to cover the surface of the Al-based alloy film 3. Then, a lower layer film 2 is formed (see FIG. 4D) to form a gate wiring. At this time, the etching of the protective film 6 and the lower film 2 is performed simultaneously since the protective film 6 and the lower film 2 are made of the same material.

The protective film 6 and the lower film 2 are made of, for example, one of the following (1) to (4).

(1) Cr, Ta, Mo, W, Ti, Cu
(2) Any one of alloys each containing Cr, Ta, Mo, W, Ti, Cu and Ni (3) Any one of SiN, SiO ₂ and TaO ₂ (4 In the present embodiment, since the etching of the lower layer film 2 is terminated when the residue of the additive is removed, the size of the concave portion formed on the side surface of the Al-based alloy film 3 is reduced. Can be reduced as much as possible, and the protective film 6 for preventing corrosion of the Al-based alloy film 3 can be more closely adhered to the surface of the Al-based alloy film 3.

[0034]

According to the present invention, a structure in which an underlayer film made of a material different from that of an Al-based alloy film is provided under a gate wiring made of an Al-based alloy film, there is no residue of additives or side hillocks at all. A highly reliable gate wiring can be formed.

[Brief description of the drawings]

FIG. 1 is a process sectional view showing one embodiment of a method for manufacturing a liquid crystal display device of the present invention.

FIG. 2 is an explanatory process sectional view showing another embodiment of the method of manufacturing the liquid crystal display device of the present invention.

FIG. 3 is a process sectional view showing another embodiment of the method of manufacturing the liquid crystal display device of the present invention.

FIG. 4 is a process cross-sectional view showing another embodiment of the method of manufacturing the liquid crystal display device of the present invention.

FIG. 5 is a process cross-sectional view illustrating a method for manufacturing a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent insulating substrate 2 Underlayer film 3 Al alloy film

Claims (8)

(57) [Claims] A gate wiring, a source wiring, and a switching element are provided on the substrate; and an array substrate having the switching element formed at an intersection of the gate wiring and the source wiring. A liquid crystal display device comprising a counter substrate provided and a liquid crystal sandwiched between the array substrate and the counter substrate, wherein a lower layer film made of a resin-based organic insulator is provided on the substrate.
And an Al-based alloy film of an alloy containing Al on the lower film
Is formed, and the Al-based alloy film and the lower film are etched.
Gate wiring is formed by the Al-based alloy film.
The liquid crystal display device, characterized by that. 2. An array substrate having a gate wiring, a source wiring, and a switching element provided on a substrate, wherein the switching element is formed at an intersection of the gate wiring and the source wiring, and facing the array substrate. A method for manufacturing a liquid crystal display device comprising a counter substrate provided and a liquid crystal sandwiched between the array substrate and the counter substrate, comprising: forming a lower layer film on the substrate; An Al-based alloy film is formed on the Al-based alloy film, and then a resist film is arranged on the Al-based alloy film in a pattern.
After the gate wiring is formed by etching the base alloy film, the lower film is wet-etched using the resist film as a mask, and then the lower wiring is formed on the lower film.
Removing the etching residue of the Al-based alloy film remaining in
A method of manufacturing a liquid crystal display device, further comprising forming a protective film on the Al-based alloy film and etching the protective film. 3. The material of the lower layer film is as follows:
3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the method is any one selected from (4). (1) Any one metal of Cr, Ta, Mo, W, Ti, Cu and Ni (2) Alloy containing any one of Cr, Ta, Mo, W, Ti, Cu and Ni (3) SiN, Insulator of one of SiO ₂ and TaO ₂ (4) Resin-based organic insulator 4. An array substrate having a gate line, a source line, and a switching element provided on a substrate, wherein the switching element is formed at an intersection of the gate line and the source line, and facing the array substrate. A method for manufacturing a liquid crystal display device comprising a counter substrate provided and a liquid crystal sandwiched between the array substrate and the counter substrate, comprising: forming a lower layer film on the substrate; An Al-based alloy film is formed on the Al-based alloy film, and then a resist film is arranged on the Al-based alloy film in a pattern.
The gate wiring is formed by etching the base alloy film
It was then, before performing the etching of the lower film partway
After removing the etching residue of the Al-based alloy film remaining on the lower layer film and removing the resist film, a protective film is formed so as to cover the Al-based alloy film and the lower layer film ,
A method for manufacturing a liquid crystal display device, comprising etching a protective film and the lower layer film . 5. The material of the lower layer film is as follows:
5. The method for manufacturing a liquid crystal display device according to claim 4, wherein the method is any one selected from (4). (1) Any one metal of Cr, Ta, Mo, W, Ti, Cu and Ni (2) Alloy containing any one of Cr, Ta, Mo, W, Ti, Cu and Ni (3) SiN, Insulator of one of SiO ₂ and TaO ₂ (4) Resin-based organic insulator 6. The method according to claim 2, wherein the lower layer film and the protective film are made of the same material. 7. An array substrate having a gate wiring, a source wiring, and a switching element provided on a substrate, wherein the switching element is formed at an intersection of the gate wiring and the source wiring, and facing the array substrate. A method of manufacturing a liquid crystal display device comprising a counter substrate provided and a liquid crystal sandwiched between the array substrate and the counter substrate, comprising: forming a lower layer film on the substrate; An Al-based alloy film is formed on the Al-based alloy film, and then a resist film is arranged in a pattern on the Al-based alloy film, and the Al-based alloy film is etched using the resist film as a mask to form the gate wiring. After removing,
A liquid crystal display device comprising: removing an etching residue of the Al-based alloy film remaining on the lower- layer film by etching the lower-layer film using the etched Al-based alloy film as a mask. Recipe. 8. The material of the lower layer film is as follows:
5. The method for manufacturing a liquid crystal display device according to claim 4, wherein the method is any one selected from (4). (1) Any one metal of Cr, Ta, Mo, W, Ti, Cu and Ni (2) Alloy containing any one of Cr, Ta, Mo, W, Ti, Cu and Ni (3) SiN, Insulator of one of SiO ₂ and TaO ₂ (4) Resin-based organic insulator