JPH05224219A - Etching method for thin film, production of substrate for liquid crystal display element and etching device - Google Patents

Abstract

PURPOSE:To provide the etching method for a thin film which prevents the generation of imperfect etching and improves the yield of a patterning stage, the process for production of the substrate for the liquid crystal display element and the etching device. CONSTITUTION:The etching method for the thin film, the process for production of the substrate for the liquid crystal display element and the etching device consist in rinsing the substrate surface with water or pure water just prior to etching of the substrate surface formed with photoresist patterns by applying an etching liquid thereto in the etching stage at the time of forming the thin film on the substrate and forming the patterns by photolithography.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a thin film, and more particularly to an etching method for patterning electrodes of a liquid crystal display element, a method for manufacturing a substrate for a liquid crystal display element and an etching apparatus.

[0002]

2. Description of the Related Art Conventionally, a technique for forming a pattern on a substrate by a photolithography process is widely known. As a conventional example, a metal electrode of a liquid crystal panel will be described as an example,
After forming a metal thin film on almost the entire surface of the glass substrate, U
A V (ultraviolet) curable resist film is applied to a thickness of about 1 μm.

Next, after the resist film is tentatively dried, it is exposed to UV light through a mask having a desired pattern, developed with a developing solution, and then main-cured. Then, the process proceeds to an etching step. In the etching process, a spray method is generally used in which the glass substrate passes through while the etching liquid is being sprayed from the upper nozzle, and this spray method is easy to implement in a production etching apparatus. It is advantageous because it is excellent in productivity. Next, the resist film on the electrodes is removed to form an electrode pattern.

[0004]

However, in the etching process of the conventional example described above, when the fine pattern is etched particularly on a large-sized substrate, the resist pattern is normally formed. The etching residue occurs at a part of the metal film.

The etching residue is usually removed by a laser or the like or a method of etching a plurality of times. However, such a method complicates the process, and a fine pattern is formed especially on a large substrate. In doing so, a large amount of etching residue is generated, and it is very difficult to remove it.

The present invention solves the above-mentioned problems of the prior art, uses a spray-type etching apparatus, prevents the occurrence of etching residues, and significantly improves the yield of the patterning process. It is an object of the present invention to provide a method of manufacturing a substrate for a liquid crystal display element and an etching apparatus used in those methods.

[0007]

That is, the first invention of the present invention is to perform a step of forming a thin film on a substrate and performing an etching step when forming a pattern by photolithography.
It is a thin film etching method characterized in that the substrate surface is rinsed with water or pure water immediately before etching by applying an etching solution to the substrate surface on which a photoresist pattern is formed.

A second aspect of the present invention is a substrate for a liquid crystal display element, wherein a thin film is formed on a substrate, a photoresist pattern is formed on the thin film, and then a pattern is formed by photolithography for etching. In the manufacturing method, a method for manufacturing a substrate for a liquid crystal display device is characterized in that the substrate surface is rinsed with water or pure water immediately before etching by applying an etching liquid to the substrate surface on which the photoresist pattern is formed.

Further, a third invention of the present invention is to form a thin film on a substrate, and a pure water pre-rinsing chamber for rinsing the surface of the substrate having a photoresist pattern formed thereon with water or pure water; An etching solution spray chamber that sprays an etching solution onto the substrate surface rinsed with pure water to etch it, a pure water spray chamber that sprays and cleans the etched substrate surface with pure water, and an air knife chamber that drains the cleaned substrate. It is an etching apparatus characterized by comprising.

In the present invention, the substrate surface is rinsed with water or pure water immediately before the thin film is etched by applying the etching liquid to the substrate surface, but normal water other than pure water can be used as the water. The rinsing method is not particularly limited as long as it can wet the surface of the substrate, and for example, spraying, dipping, spinner coating or the like can be performed. The thin film formed on the substrate is made of Al, Mo,
A metal film made of Cr, Ta, Cu, Ni or an alloy thereof, or a transparent conductive film is used.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples.

Embodiment 1 FIG. 1 is an explanatory view showing an example of an etching apparatus used in the thin film etching method of the present invention. In the figure, a first chamber A is a pure water pre-rinsing chamber in which a thin film is formed on a substrate and a substrate surface having a photoresist pattern formed thereon is rinsed with water or pure water. The third chamber C is an etching liquid spray chamber in which an etching liquid is applied to the substrate surface rinsed with water or pure water to perform etching.
A pure water spray chamber for spraying pure water onto the surface of the etched substrate for cleaning, a fourth chamber D is an air knife chamber for draining the cleaned substrate, and the etching apparatus of the present invention includes first chambers A to It consists of a combination of the fourth chamber D in series.

The etching of the thin film was carried out by the following method using the etching apparatus shown in FIG. Mo is deposited on a glass substrate having a length of 300 mm, a width of 300 mm, and a thickness of 1.0 mm to a thickness of 1500 Å by a sputtering method, and a photoresist is applied to a thickness of about 1 μm by a roll coater.
Pre-baking, exposure, development, and post-baking steps are performed, and a substrate 4 on which a photoresist pattern of 1200 stripe electrodes having a line pitch: 200 μm, a line width: 197 μm, a line interval: 3 μm, and a line length: 250 mm is formed according to the present invention. Etching was performed by the method shown in FIG.

In the etching step, while the substrate 4 is conveyed to the etching apparatus shown in FIG. 1 at a speed of 0.6 m / min, pure water is sprayed in the first chamber A to wet the entire substrate surface. Next, in the second chamber B, an etching solution (phosphoric acid (85
wt%): nitric acid (60 wt%): acetic acid (98 wt%):
A mixed solution of water = 16: 2: 1: 1 (vol%), the liquid temperature is room temperature) is sprayed for 90 seconds to perform etching, and pure water is sprayed again in the third chamber C for 90 seconds to make the fourth Drained with an air knife in the chamber D. Then, the photoresist was peeled off to form a Mo patterned substrate. This M
o There was no etching residue on the patterned substrate.

Comparative Example 1 Using the conventional etching apparatus shown in FIG. 3, a thin film was etched by the following method. Vertical 300 mm, horizontal 30
Mo on a glass substrate with a thickness of 0 mm and a thickness of 1.0 mm.
A film having a thickness of 0 Å was formed by a sputtering method, and exactly the same method as in Example 1, the same stripe electrodes: 1200 electrodes (line pitch: 200 μm, line width: 197 μm, space width: 3 μm, line length: After forming a resist pattern of 250 μm), as shown in FIG. 3, as in Example 1, the etching solution was sprayed in the first chamber to perform etching, and pure water was sprayed in the second chamber. Drained with an air knife in the third chamber.

After etching by the above method, the resist was peeled off to form a Mo patterned substrate. As a result, 1000 or more etching residues were generated on the entire surface of the substrate, and most of them were short-circuit defects between lines. Oops.

Embodiment 2 FIG. 2 is an explanatory view showing another example of the etching apparatus used in the thin film etching method of the present invention. The figure shows the first room A
However, it is characterized by comprising a pure water pre-rinse chamber for rinsing the substrate surface by immersing the substrate in the pure water tank 1 to which the pure water 2 is supplied from the pump 3.

A thin film was etched by the following method using the etching apparatus shown in FIG. Al on a glass substrate of vertical 300 mm, width 300 mm, thickness 1.0 mm
A film having a thickness of 500 Å was formed, and exactly the same stripe electrodes as in Example 1 were used: 1200 electrodes (line pitch: 200 μm, line width: 197 μm, space width:
After forming a photoresist pattern of 3 μm, line length: 250 μm), etching was performed by the method shown in FIG.

In the etching step, the substrate 4 is transported to the etching apparatus shown in FIG. 2 at a speed of 0.6 m / min, and is immersed in pure water in the first chamber A to wet the entire substrate surface. In the second chamber B, the etching solution (phosphoric acid (85 wt%):
Nitric acid (60 wt%): Acetic acid (98 wt%): Water = 16:
Etching is performed by spraying a 2: 1: 1 (vol%) mixed solution at a liquid temperature of 40 ° C for 90 seconds, spraying pure water again in the third chamber C for 90 seconds, and airing in the fourth chamber D. Drained with a knife. Then, when the photoresist was peeled off to form an Al patterned substrate, almost no etching residue was generated as in Example 1 described above.

Example 3 An example in which the present invention is applied to a step of forming a transparent electrode used for a liquid crystal display element substrate is shown below. Here, as the etching apparatus, the same apparatus as that shown in FIG. 1 shown in Example 1 was used to etch the ITO thin film by the following method.

After ITO was formed into a film having a thickness of 1500 Å on a glass substrate having a length of 300 mm, a width of 300 mm and a thickness of 1.0 mm by a sputtering method, and a photoresist was applied to a thickness of about 1 μm by a roll coater. , Pre-bake, exposure, development, post-bake process, line pitch: 2
00 μm, line width: 197 μm, line spacing: 3 μm,
The substrate 4 on which the photoresist pattern of 1200 stripe-shaped electrodes having a line length of 250 mm was formed was etched by the method shown in FIG. 1 of the present invention.

In the etching process, while the substrate 4 is being transported to the etching apparatus shown in FIG. 1 at a speed of 0.6 m / min, pure water is sprayed in the first chamber A to wet the entire substrate.

Next, in the second chamber B, an etching solution (hydroiodic acid 55%) is heated to 45 ° C. and sprayed for 120 seconds to perform etching. In the third chamber C, pure water is sprayed again. Then, it was drained with an air knife in the fourth chamber D.

Then, the photoresist is peeled off, and the IT
A pattern with O transparent electrodes was formed. No etching residue was found in this ITO pattern, and good results were obtained.

[0025]

As described above, in the thin film microfabrication process, the etching method according to the present invention is used,
By performing pre-rinsing with water or pure water before applying the etching liquid in the etching step and performing etching, it is possible to eliminate the occurrence of etching residue and significantly improve the yield in the patterning step.

Further, according to the method of manufacturing a substrate for a liquid crystal display element of the present invention, it is possible to eliminate the generation of etching residue, and it is possible to remarkably improve the yield in the patterning step.

By using the etching apparatus of the present invention, pre-rinsing can be performed with water or pure water before etching by applying an etching solution in the etching step, and it is possible to eliminate the occurrence of etching residue and to perform the patterning step. Yield can be significantly improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of an etching apparatus used in a thin film etching method of the present invention.

FIG. 2 is an explanatory view showing another example of an etching apparatus used in the thin film etching method of the present invention.

FIG. 3 is an explanatory view showing an etching apparatus used in a conventional thin film etching method.

[Explanation of symbols]

 1 Pure water tank 2 Pure water 3 Pump 4 Substrate

Claims (7)

[Claims] 1. In a step of forming a thin film on a substrate and forming a pattern by photolithography, in the etching step, the surface of the substrate on which a photoresist pattern is formed is immediately before etching by applying an etching solution to the surface of the substrate. A method for etching a thin film, which comprises rinsing water with water or pure water. 2. The thin film is made of Al, Mo, Cr, Ta, C
The method for etching a thin film according to claim 1, which is a metal film made of u, Ni or an alloy thereof. 3. The method for etching a thin film according to claim 1, wherein the thin film is a transparent conductive film. 4. A method for manufacturing a substrate for a liquid crystal display device, which comprises forming a thin film on a substrate, forming a photoresist pattern on the thin film, and then forming a pattern by photolithography, wherein the photoresist pattern is formed. A method for manufacturing a substrate for a liquid crystal display element, characterized in that the substrate surface is rinsed with water or pure water immediately before etching by applying an etching solution to the substrate surface. 5. The thin film is made of Al, Mo, Cr, Ta, C.
The method for manufacturing a substrate for a liquid crystal display element according to claim 4, which is a metal film made of u, Ni or an alloy thereof. 6. The method for manufacturing a liquid crystal display element substrate according to claim 4, wherein the thin film is a transparent conductive film. 7. A pure water pre-rinsing chamber in which a thin film is formed on a substrate and a photoresist pattern is formed on the thin film is rinsed with water or pure water, and a substrate surface rinsed with water or pure water is etched. An etching apparatus comprising an etching liquid spray chamber for applying a liquid to etch, a pure water spray chamber for spraying pure water on the surface of an etched substrate to wash it, and an air knife chamber for draining the washed substrate. .