JPH10133210A - Patterning method for transparent conductive film - Google Patents

Abstract

(57) [Summary] [Problem] There is a problem that the etching residue of a transparent conductive film cannot be visually or optically recognized. SOLUTION: This is a transparent conductive film patterning method for forming a transparent conductive film on a substrate and etching away other portions so that the transparent conductive film remains in a predetermined shape, wherein the transparent conductive film is removed. A metal film is provided below the portion to be removed, and the transparent conductive film is removed by etching, and the metal film below the transparent conductive film is removed by etching.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for patterning a transparent conductive film, and more particularly to a method for patterning a transparent conductive film used for a pixel electrode of a liquid crystal display device.

[0002]

2. Description of the Related Art A pixel electrode of a liquid crystal display device is formed of a transparent conductive film such as ITO (indium tin oxide). As shown in FIG. 2, a transparent conductive film 12 is once formed on the entire or substantially entire surface of a transparent substrate 11 made of glass or the like by a sputtering method or the like as shown in FIG. a)), an etching resist film 13 is formed in a predetermined shape on the transparent conductive film 12 (FIG. 2).
(B)) The substrate 11 was immersed in a hydrochloric acid-based etchant for a predetermined time to etch away the transparent conductive film 12 other than the portion where the resist film 13 was formed, thereby patterning the substrate 11 into a predetermined shape. (FIG. 2 (c)). In this case, the end point of the etching of the transparent conductive film 12 is determined by time measurement in consideration of the thickness of the transparent conductive film 12, the composition of the etching solution, the liquid temperature, and the like.

[0003]

However, when the patterning of the transparent conductive film 12 is performed by measuring the time taking into account the thickness of the transparent conductive film 12, the composition of the etching solution, the liquid temperature, and the like, as in the prior art, the transparent conductive film 12 is transparent. The accuracy of the etching of the transparent conductive film 12 greatly differs depending on the film quality of the film 12 and the state of the etching solution, and there is a problem that the etching residue of the transparent conductive film 12 and over-etching easily occur. When the etching residue of the transparent conductive film 12 occurs, a short circuit or the like occurs between the adjacent island-shaped transparent conductive films 12, and display failure occurs when used in a liquid crystal display device. On the other hand, when overetching occurs, the shape of the island-shaped transparent conductive film 12 becomes smaller due to side shift.

Further, even if the etching residue of the transparent conductive film 12 occurs, the etching residue cannot be visually or optically recognized because the transparent conductive film 12 itself is transparent, and the electrical characteristics are inspected. Until then, there has been a problem that it is difficult to find this etching residue.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been developed to solve the problem that the etching residue of the transparent conductive film cannot be visually or optically recognized. It is an object to provide a patterning method.

[0006]

In order to achieve the above object, in the method for patterning a transparent conductive film according to the present invention, a transparent conductive film is formed on a substrate and the transparent conductive film remains in a predetermined shape. In a method of patterning a transparent conductive film, the other portion is removed by etching, a metal film is provided below a portion where the transparent conductive film is removed, and the transparent conductive film is removed by etching. The film is also etched away.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a view showing one embodiment of a method for patterning a transparent conductive film according to the present invention, wherein 1 is a substrate made of glass or the like, 2 is a metal film, and 3 is a transparent conductive film.

As the substrate 1, a soda glass substrate or a non-alkali glass substrate is used. Soda-based glass is mainly composed of silicic acid, soda ash, and lime, and is relatively inexpensive. However, the electrical properties of the transparent conductive film 3 formed on the surface of the glass substrate are deteriorated by the alkali component, May become cloudy. Further, when the alkali component dissolves in the liquid crystal material, the contrast is lowered, the image is deteriorated, and the like. Therefore, when soda glass is used, a protective film made of silicon dioxide (SiO ₂ ) is formed on the surface of the substrate 1. In the case of non-alkali glass containing no alkali component, such a protective film (not shown) is not necessarily required.

Next, as shown in FIG. 1B, a metal film 2 is formed on a substrate 1 in a predetermined region. The metal film 2 is made of, for example, titanium (Ti), tantalum (Ta), chromium (C
r) and the like. When the metal film 2 is formed of such a metal, a signal wiring, a transistor electrode, and the like can be formed simultaneously with the formation of the metal film 2 when a liquid crystal display device is formed. The metal film 2 has a thickness of 0.1 to 0.5 μm by a vacuum evaporation method, an electron beam evaporation method, a sputtering method, or the like.
The thickness is about m. The metal film 2 is formed in a predetermined shape on a predetermined portion on the substrate 1, and is finally patterned together with the transparent conductive film 3. The metal film 2 may be a single-layer film made of the above-described metal, or may be a multi-layer film.

[0010] Next, as shown in FIG.
A transparent conductive film 3 is formed thereon. The transparent conductive film 3 includes tin oxide (SnO ₂ ) and indium oxide (In ₂ O).
₃ ), indium tin oxide (ITO) or the like is used. Such a transparent conductive film 3 is formed to a thickness of about 0.05 μm by a vacuum evaporation method, a sputtering method, or the like. This transparent conductive film 3 is used for a pixel electrode or the like of a liquid crystal display device.

Next, as shown in FIG. 1D, a resist film 4 is formed on the transparent conductive film 3, and a part of the metal film 2 formed below the transparent conductive film 3 is covered. Patterning as follows. The resist film 4 may be either a positive type or a negative type.

Next, the substrate 1 is immersed in a hydrochloric acid-based etchant to etch away the transparent conductive film 3 other than the portion where the resist film 4 is formed. In this case, the transparent conductive film 3 is etched, and the metal film 2 below the etched transparent conductive film 3 is also removed by etching. When the etching residue remains on the transparent conductive film 3, the metal film 2 also remains, so that the etching residue on the transparent conductive film 3 can be found very easily. Therefore, the etching time calculated at the time of design can be set more strictly, and the occurrence of side shift caused by increasing the etching time can be suppressed.

In this case, if the transparent conductive film 3 is etched such that the metal film 2 remains at the end of the portion where the transparent conductive film 3 remains, the color contrast between the etched portion and the unetched portion becomes stronger, Etching residues can be more easily found.

It is preferable from the viewpoint of simplification that the etching solution and the etching process of the transparent conductive film 3 and the metal film 2 be the same, but they are not necessarily the same.

Finally, as shown in FIG. 1E, the resist film 4 is removed, and the patterning of the transparent conductive film 3 is completed. The metal film 2 may be left as it is on the periphery of the transparent conductive film 3.

[0016]

As described above, according to the method for patterning a transparent conductive film according to the present invention, a metal film is provided below a portion where the transparent conductive film is removed, and the transparent conductive film is etched and removed. Since the metal film below the transparent conductive film is also removed by etching, the end point of etching at the time of patterning the transparent conductive film can be determined by the metal film.
The end point can be reliably determined. Further, even if the transparent conductive film at the portion to be removed by etching remains thin, it can be removed together with the subsequent etching of the lower metal film,
Short circuit failure of the pixel electrode can also be reduced. Further, when the transparent conductive film remains thick, the position of the etching defect can be visually confirmed because the lower metal film also remains, so that the repair work by laser or the like can be easily performed.

[Brief description of the drawings]

FIG. 1 is a view showing a method for patterning a transparent conductive film according to the present invention.

FIG. 2 is a diagram showing a conventional method for patterning a transparent conductive film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Metal film, 3 ... Transparent conductive film

Claims (3)

[Claims] 1. A method for patterning a transparent conductive film, comprising forming a transparent conductive film on a substrate and etching away other portions so that the transparent conductive film remains in a predetermined shape, the transparent conductive film is removed. A method of patterning a transparent conductive film, comprising: providing a metal film below a portion, etching the transparent conductive film, and etching away the metal film below the transparent conductive film. 2. The transparent conductive film according to claim 1, wherein the transparent conductive film and the metal film are removed by etching so that the metal film remains at an end of a portion where the transparent conductive film remains. Patterning method. 3. The patterning method for a transparent conductive film according to claim 2, wherein the metal film is made of one or more of titanium, tantalum, and chromium.