JP2002164332A - Etchant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etchant, for a transparent conductive film, in which a foaming property is suppressed and by which residues will not be generated, after etching operation. SOLUTION: The etchant composition contains the etchant for the transparent conductive film and one kind or two or more kinds of compounds, selected from among a group composed of a polysulfonic acid compound and a polyoxyethylene-polyoxypropylene block copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an etching solution for a transparent electrode film of a display device such as an LCD.

[0002]

2. Description of the Related Art Indium tin oxide, indium oxide, tin oxide, zinc oxide and the like are used as transparent electrodes of LCDs and electroluminescent display elements, and indium tin oxide (hereinafter referred to as ITO) is mainly used. As an etching solution for the ITO film, an aqueous solution of iron (III) chloride, an aqueous solution of iodic acid, an aqueous solution of phosphoric acid, a mixed solution of hydrochloric acid and nitric acid (aqua regia), and an aqueous solution of oxalic acid have been proposed. However, these have the following problems,
It is not enough for practical use.

[0003] An aqueous solution of iron (III) chloride has a high etching rate and is inexpensive, but has a large side etching amount.
It also has the disadvantage of containing Fe, which has an adverse effect on semiconductors. The iodic acid aqueous solution has a small amount of side etching and has good etching characteristics, but it is easy to release iodine, lacks stability, and is expensive. The phosphoric acid aqueous solution etches Al used for the wiring, and a residue remains after the etching. A mixture of hydrochloric acid and nitric acid (aqua regia) changes drastically with time, it is difficult to control the process, and it cannot be delivered. The oxalic acid aqueous solution is excellent in stability, inexpensive, and has many advantages such as not etching Al, but a residue remains after etching.

[0004] Regarding the residue when an oxalic acid aqueous solution is used, a technique of reducing the residue by using dodecylbenzenesulfonic acid is disclosed in Japanese Patent Application Laid-Open No. 7-141932.
This had the disadvantage of high foaming properties. In recent years, silicon nitride films and the like have been formed on glass substrates, and IT
A process for forming an O film is also being studied, and the structure of the element is also changing. Therefore, the removability of the residue has become insufficient.

[0005]

That is, an object of the present invention is to provide an etching solution for a transparent conductive film, which solves the above-mentioned conventional problems and has suppressed foaming properties and does not generate residues after etching. It is in.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and studied to include a polysulfonic acid compound and a specific surfactant in an etching solution for a transparent conductive film. As a result, they have found that such a problem can be solved, and as a result of further research, they have completed the present invention.

That is, the present invention provides an etching solution for a transparent conductive film,
The present invention relates to an etching solution composition containing one or more compounds selected from the group consisting of a polysulfonic acid compound and a polyoxyethylene-polyoxypropylene block copolymer. The present invention also relates to the above composition, wherein the transparent conductive film is an indium tin oxide (ITO) film. Further, the present invention relates to the composition, wherein the etchant for the transparent conductive film is an oxalic acid aqueous solution. Further, the present invention is characterized in that the concentration of one or more compounds selected from the group consisting of a polysulfonic acid compound and a polyoxyethylene-polyoxypropylene block copolymer is 0.0001 to 10% by mass, It relates to the above composition.
Furthermore, the present invention is characterized in that the polysulfonic acid compound is one or more selected from naphthalenesulfonic acid formaldehyde condensate and its salt, polystyrenesulfonic acid and its salt, and ligninsulfonic acid and its salt. The composition described above. The present invention also relates to the above composition, further comprising a sulfonate-type anionic surfactant. Furthermore, the present invention relates to the above-mentioned composition, further comprising a water-soluble lower alcohol. The present invention also relates to the above composition, wherein the water-soluble lower alcohol is one or more selected from methanol, ethanol, n-propanol, isopropanol and n-butanol. Furthermore, the present invention relates to the above composition, wherein the concentration of the water-soluble lower alcohol is 1 to 10% by mass.

[0008] According to the present invention, the polyoxyethylene-polyoxypropylene block copolymer has an action of removing residues after etching of the ITO film, and more surprisingly, the polyoxyethylene-polyoxypropylene block copolymer and the sulfonate type anionic surfactant It has been found that the removal action is further enhanced when a polyoxyethylene-polyoxypropylene block copolymer is combined. In addition, it was also found that a polyoxyethylene-polyoxypropylene block copolymer and a water-soluble alcohol have a foam-suppressing effect on foaming by a sulfonate-type anionic surfactant.

[0009]

Embodiments of the present invention will be described below in detail. First, the concentration of oxalic acid used in the present invention is determined within a range where the etching rate is sufficient and crystals do not precipitate. When the concentration of oxalic acid is 0.1% by mass or less, the etching rate at 50 ° C. is 100 ° / min or less,
A practical etching rate cannot be obtained. 2 for 10% or more
Crystals precipitate at 5 ° C. or less, which hinders storage stability and delivery. Particularly preferred concentrations are believed to be 0.5-5% by weight.

[0010] The polysulfone compound used in the present invention includes polymers such as naphthalene sulfonic acid formaldehyde condensate and salts thereof, polystyrene sulfonic acid and salts thereof, lignin sulfonic acid and salts thereof, and polyethylene sulfonic acid and salts thereof. Compounds and aromatic polysulfonic acids such as 1,5-naphthalene-disulfonic acid and 1-naphthol-3,6-disulfonic acid, and salts thereof. Among them, naphthalenesulfonic acid formaldehyde condensate and its salt, polystyrenesulfonic acid and its salt, ligninsulfonic acid and its salt are particularly preferable.

[0011] The naphthalenesulfonic acid formaldehyde condensate and its salt include Polystar NP100 (Nippon Yushi Co., Ltd.), Lunox 1000, 1000C, 1500A
(Toho Chemical Industry Co., Ltd.), Ionnet D-2,
Sanyo Levelon PHL (Sanyo Kasei Co., Ltd.), Rome PWA-40 (San Nopco Co., Ltd.), Demol N,
It is commercially available under the trade name such as Demole AS (Kao Corporation). In particular, ammonium salts and free acids,
Roman PWA-40 and Demol AS are preferred. Polystyrene sulfonic acid and its salt are trade names of POLY 1900 (Lion Corporation), and lignin sulfonic acid or its salt is Solpol 9047K
(Toho Chemical Industry Co., Ltd.), and sodium salts are commercially available. When used for the electronics industry, those containing metals such as sodium are not preferred, and can be used by treating with an ion exchange resin or the like to remove sodium.

[0012] The polyoxyethylene-polyoxypropylene block copolymer used in the present invention is itself ITO
In addition to reducing the residue after film etching, the combination with the sulfonic acid compound greatly improves the removability of the residue and also has the effect of suppressing foaming. There are various types of polyoxyethylene-polyoxypropylene block copolymers depending on the ratio and molecular weight of polyoxyethylene and polyoxypropylene, and many are marketed by surfactant manufacturers.
For example, Sanyo Chemical Industries, Ltd. New Pole PE series (PE-61, 62, 64, 68, 71, 74, 7)
5, 78, 108, 128) and the Epan series (Epan 410, 420, 450, 48) of Daiichi Kogyo Seiyaku Co., Ltd.
5,710,720,740,750,785). Those having a high polyoxypropylene content of 80 to 90% are effective in defoaming.
% Or more has a remarkable effect on removal of residues after etching.

The sulfonate-type anionic surfactants used in the present invention include alkyl benzene sulfonic acids such as dodecyl benzene sulfonic acid and salts thereof, alkyl sulfates and salts thereof, dialkyl esters of sulfosuccinic acid and salts thereof, and polyoxysulfonic acids. Examples include ethylene alkyl ether sulfonic acid, polyoxyethylene allyl ether sulfonic acid, and salts thereof. Among them, polyoxyethylene alkyl ether sulfonic acid, polyoxyethylene allyl ether sulfonic acid and salts thereof are relatively less foaming and are particularly preferable. These are brand names New
col 560SF, Newcol 707SF (Nippon Emulsifier Co., Ltd.), Nissan Avanel S series (Nippon Yushi Co., Ltd.) and the like are commercially available. These sulfonate-type anionic surfactants, like the above-mentioned polysulfonic acid compounds, have a property of removing residues at the time of etching, but have an insufficient foaming property. To suppress foaming, a water-soluble lower alcohol may be added. As the water-soluble lower alcohol, methanol, ethanol, n-propanol, isopropanol, n-butanol and the like can be used. The concentration of the water-soluble lower alcohol is 1
-10% by mass is preferred. If the concentration is too low, the effect of use cannot be obtained, and if the concentration is too high, the resist may swell, causing problems.

The concentration of the polysulfonic acid compound, sulfonate type anionic surfactant or polyoxyethylene-polyoxypropylene block copolymer is 0.0001.
-10 mass%, particularly preferably 0.001-10 mass%
It is. Polysulfonic acid compound and polyoxyethylene-
When the polyoxypropylene block copolymer is combined, the content of the polysulfonic acid compound is 0.001 to 10% by mass and the content of the polyoxyethylene-polyoxypropylene block copolymer is 0.0001 to 1% by mass. The propylene block copolymer can be freely blended in this concentration range. When the concentration of the polysulfonic acid compound, the sulfonate-type anionic surfactant or the polyoxyethylene-polyoxypropylene block copolymer is low, the effect of removing the residue is not sufficient, and the effect corresponding thereto cannot be expected even if the concentration is too high. . These compounds need to be appropriately selected depending on the base material of the ITO film. For example, a polysulfonic acid compound on a glass substrate
The effect is exhibited at 0.1% by mass, but the effect is not seen on the silicon nitride film unless the concentration is increased to 0.1 to 10% by mass.

[0015]

EXAMPLES Examples of the present invention are shown below together with comparative examples.
The details of the present invention will be described in detail, but the present invention is not limited to these examples.

Table 1 shows the etching solution of the present invention and the composition of the etching solution for comparison.

[Table 1]

The following items were examined for the above-mentioned etching solutions. (Foamability-Foam height-) 20 samples were placed in a 100 ml colorimetric tube.
ml, set on a TS-type shaker, and shaken for 2 minutes. After stopping the shaking, the foam height was measured 30 seconds and 5 minutes later, and the foaming property was evaluated. (Etching rate) Amorphous IT with 1500Å film thickness
The substrate on which the resist pattern was formed on the O film was immersed in an etching solution at 50 ° C. for 1 minute, washed with water, dried, the resist was peeled off, and the amount of etching was measured with a stylus thickness gauge. (Residue after etching) The substrate on which the ITO film was formed on the glass substrate was etched for 1.8 times the just etching time calculated from the etching rate. evaluated. A silicon nitride film is formed on a glass substrate, and the substrate on which the ITO film is formed is etched for 1.8 times the just etching time calculated from the etching rate. The residue was evaluated.

Table 2 shows the results.

[Table 2]

Claims (9)

[Claims] 1. An etching solution for a transparent conductive film, and 1 selected from the group consisting of a polysulfonic acid compound and a polyoxyethylene-polyoxypropylene block copolymer.
An etchant composition comprising a species or two or more compounds. 2. The method according to claim 1, wherein the transparent conductive film is made of indium tin oxide (IT).
O) The composition according to claim 1, which is a film. 3. The composition according to claim 1, wherein the etchant for the transparent conductive film is an oxalic acid aqueous solution. 4. The method according to claim 1, wherein the concentration of one or more compounds selected from the group consisting of a polysulfonic acid compound and a polyoxyethylene-polyoxypropylene block copolymer is 0.0001 to 10% by mass. The composition according to claim 1. 5. The polysulfonic acid compound is one or more selected from naphthalenesulfonic acid formaldehyde condensate and salts thereof, polystyrenesulfonic acid and salts thereof, and ligninsulfonic acid and salts thereof. The composition according to claim 1, wherein 6. The composition according to claim 1, further comprising a sulfonate type anionic surfactant. 7. The composition according to claim 1, further comprising a water-soluble lower alcohol. 8. The water-soluble lower alcohol is methanol,
The composition according to claim 7, wherein the composition is one or more selected from ethanol, n-propanol, isopropanol, and n-butanol. 9. The concentration of the water-soluble lower alcohol is from 1 to 10
The composition according to claim 7, wherein the composition is mass%.