TWI493030B - Indium oxalate dissolving agent composition and a method for washing inside an etching equipment system using the same - Google Patents

Description

Indium oxalate dissolvant composition and cleaning method in an etching device system using the same

The present invention relates to a dissolving agent capable of dissolving and removing indium oxalate precipitated in an etching apparatus system of ITO (indium tin oxide) or IZO (indium zinc oxide).

In an FPD (Flat Panel Display) display device such as an LCD (Liquid Crystal Display) or an ELD (Electroluminescence Display), a transparent conductive film is used for a display electrode of a pixel or the like. As a material of such a transparent conductive film, ITO (indium tin oxide), IZO (indium zinc oxide), or the like is widely used. In general, an etchant using oxalic acid as a main component (for example, Patent Document 1) is used for processing a display electrode using ITO or IZO, and the patterned photoresist is used as a mask by photolithography to wet ITO and IZO. Etching, thereby forming a target ITO, IZO display electrode pattern.

The wet etching of the ITO film or the IZO film using the etchant liquid containing oxalic acid as the main component utilizes the chelating effect of oxalic acid to form an indium oxalate by dissolving indium in the main component of ITO or IZO, and etching. Such an etching solution containing oxalic acid as a main component is continuously used for a long period of time, and there is a problem that indium oxalate is insoluble in the etching liquid and precipitates in the wet etching apparatus system (for example, Patent Document 2).

These indium oxalates are precipitated in a wet etching apparatus system such as a pipe, a valve, a filter, a pump, a nozzle, a substrate transfer roller, an inner wall of a wet etching chamber, or a buffer tank, and cause the following problems.

For example, an abnormality such as a decrease in the inner diameter of the pipe, a malfunction of the valve switch or the pump, and a blockage of the filter or the nozzle occur. When such an abnormality occurs in the etching treatment step, the in-plane uniformity is lowered, the etching shape is poor, and the like, and the etching property is greatly affected, which is a fatal problem in which the yield of the product is lowered.

Previously, in response to the above problems, it has been proposed to periodically and physically recover indium oxalate precipitated in the wet etching apparatus system. That is, water or hot water is circulated and washed at a high flow rate, and the indium oxalate precipitated in the apparatus system is removed and removed. Further, for the indium oxalate which was not removed by the circulation washing, the etching liquid was completely discharged from the wet etching apparatus system, and the indium oxalate was manually scraped off.

Prior technical literature

[Patent Literature]

[Patent Document 1] JP-A-2005-244083

[Patent Document 2] JP-A-2006-77241

The present invention provides an indium oxalate dissolving agent which solves the previous problem and chemically dissolves and removes a wet etching device system which is formed of a transparent conductive film composed of an indium tin oxide (ITO) film or an indium zinc oxide (IZO) film. Indium oxalate precipitated inside.

The inventors of the present invention have repeatedly studied and solved the above problems, and as a result, it has been found that an alkaline aqueous solution containing an amine-based polycarboxylic acid can efficiently dissolve and remove indium oxalate. Further, it has been found that the present invention can be completed by further increasing the maximum amount of indium oxalate dissolved by further containing a compound composed of an amine-based polycarboxylic acid amine salt.

That is, the present invention relates to a solvent composition for dissolving and removing a dissolving agent composition of indium oxalate precipitated in an etching apparatus system, characterized in that it contains an alkali component and is selected from an amine-based polycarboxylic acid and One or two or more aqueous solutions of the salt.

Further, the present invention relates to the above-mentioned solvent composition having a pH in the range of 9 to 11.

Furthermore, the present invention relates to the above-mentioned solvent composition in which the concentration of one or more compounds selected from the group consisting of an amine-based polycarboxylic acid and a salt thereof is 1 to 40% by weight.

Further, the present invention relates to the above-mentioned solvent composition containing at least one or two or more compounds selected from the group consisting of amine polycarboxylic acids.

Further, the present invention relates to at least one of a compound containing a compound selected from the group consisting of an amine-based polycarboxylic acid and a compound selected from the group consisting of an amine-based polycarboxylic acid amine salt, and the above-mentioned solvent composition.

The present invention further relates to the above-mentioned dissolving agent having a concentration of 1 to 20% by weight of a compound selected from the group consisting of amine-based polycarboxylic acid amine salts, and a concentration of the compound selected from the group consisting of amine-based polycarboxylic acids Composition.

The present invention relates to an amine-based polycarboxylic acid selected from the group consisting of ethylenediamine diacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triamethylenetetraamine hexaacetic acid, and trans-1,2-cyclohexanediamine. The above solvating agent composition of acetic acid.

Furthermore, the salt of the amine polycarboxylic acid of the present invention is ethylenediamine diacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triamethylenetetraamine hexaacetic acid, trans-1,2-cyclohexane. The above-mentioned solvent composition of the amine salt of amine tetraacetic acid.

Further, the present invention relates to the above-mentioned solvent composition of any one of an alkali component, ammonia, sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide.

Still further, the present invention relates to a method of cleaning in an etching apparatus system comprising the steps of:

(1) a step of discharging the etching liquid from the etching apparatus system and then washing it with water until the pH becomes neutral;

(2) a step of chemically dissolving and removing indium oxalate precipitated in the apparatus system using the above-mentioned solvent;

(3) After removing the solvent, it is washed with water until the pH becomes neutral.

Further, the present invention relates to the above-described washing method comprising the above-described solvent composition which is recovered and used in the dissolution and removal step.

The present invention further relates to the above-described cleaning method of a wet etching apparatus for a transparent conductive film comprising an ITO film or an IZO film.

The present invention relates to the above-described cleaning method for dissolving and removing indium oxalate precipitated at one or two or more positions selected from a pipe, a valve, a filter, a pump, a nozzle, a substrate transfer roller, an inner wall of a wet etching chamber, and a buffer tank. .

According to the present invention, it is known that an amine-based polycarboxylic acid has a function of efficiently dissolving indium oxalate in an aqueous solution by utilizing its chelation effect. Further, it is known that the maximum dissolved amount of indium oxalate in an aqueous solution can also be increased by a combination of an amine-based polycarboxylic acid and an amine-based polycarboxylic acid amine salt.

Form of implementing the invention

Embodiments of the present invention are described in detail below.

The indium oxalate dissolving agent of the present invention contains a chelating agent selected from the group consisting of an amine polycarboxylic acid and a salt thereof, and a composition of an alkali component. A chelating agent refers to a compound containing a plurality of electron donors (coordinators) having a coordination bond ability in a metal ion, and a compound having two or more ligands is collectively referred to as a multi-seat ligand (chelating agent). ). The chelating agent is characterized by the formation of a water-soluble metal chelating compound by entrapment of metal ions in the solution by its own ligand.

The amine-based polycarboxylic acid used in the indium oxalate dissolving agent of the present invention may, for example, be ethylenediaminediacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triamethylenetetraamine hexaacetic acid, or 1,2-cyclohexanediaminetetraacetic acid, and the like. From the viewpoint of obtaining cost and chelation ability, ethylenediaminetetraacetic acid is preferred.

The amine-based polycarboxylate suitable for use in the indium oxalate dissolving agent of the present invention may, for example, be an ammonium salt, an amine salt, a sodium salt, a potassium salt or a calcium salt. When used as an electronic industry, an alkali metal such as sodium or potassium is preferred as an ammonium salt or an amine salt because it deteriorates the electrical properties of the device.

The alkali component used in the indium oxalate dissolving agent of the present invention may, for example, be ammonia, sodium hydroxide, potassium hydroxide or tetramethylammonium hydroxide. When used as an electronic industry, an alkali metal such as sodium or potassium may be a factor of deterioration of electrical properties of the device, and ammonia or tetramethylammonium hydroxide is preferred, which is preferable from the viewpoint of cost, etc. It is ammonia.

The concentration of the amine-based polycarboxylic acid and the salt thereof of the present invention is preferably from 1 to 40% by weight, more preferably from 1 to 20% by weight, particularly preferably from 1 to 10% by weight. When it is less than 1% by weight, a sufficient sequestration effect cannot be obtained, and the amount of indium oxalate dissolved is extremely small. Further, the addition amount of more than 40% by weight does not provide an effect corresponding to the added amount, which is uneconomical.

The indium oxalate dissolving agent of the present invention preferably contains at least a compound selected from the group consisting of aminopolycarboxylic acids from the viewpoint of chelating ability.

More preferably, it further contains an amine-based polycarboxylate amine salt as an additional chelating agent. The present inventors have found that an additional chelating agent selected from the group consisting of amine-based polycarboxylic acid amine salts can be added to a chelating agent selected from the group consisting of amino-based polycarboxylic acids and salts thereof, and can be used alone. The chelating agent has a higher chelation effect.

The amine polycarboxylic acid amine salt may, for example, be ethylenediamine diacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triamethylenetetraamine hexaacetic acid or trans-1,2-cyclohexanediamine. Tetraacetic acid, these amine salts. Among them, ethylenediaminetetraacetic acid amine salt is preferred in terms of cost of acquisition and chelating ability.

The amine used for the amine-based polycarboxylic acid amine salt is an alkanolamine represented by monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine or the like. An alkylamine represented by monomethylamine, monoethylamine, isopropylamine, mono-n-butylamine or the like. In particular, alkanolamines, which have a plurality of ligands and have the ability to form metal chelate, are considered to be capable of easily forming a chelate compound with indium.

The concentration of the amine polycarboxylic acid used together with the amine polycarboxylate amine salt is preferably from 1 to 20% by weight, more preferably from 1 to 10% by weight. When the concentration of the aminopolycarboxylic acid is less than 1% by weight, a sufficient sequestration effect cannot be obtained, and the amount of indium oxalate dissolved is extremely small. Moreover, the addition amount of more than 20% by weight cannot obtain an effect corresponding to the added amount, which is uneconomical.

The concentration of the amine-based polycarboxylate amine salt used as an additional chelating agent is from 1 to 20% by weight, preferably from 1 to 10% by weight. When the concentration of the amine-based polycarboxylic acid amine salt is less than 1% by weight, a sufficient sequestration effect cannot be obtained, and the amount of dissolution of indium oxalate is extremely small. Moreover, the addition amount of more than 20% by weight cannot obtain an effect corresponding to the added amount, which is uneconomical.

The concentration of the alkaline aqueous solution used in the indium oxalate dissolving agent of the present invention must be adjusted within a pH range in which the chelating agent of the amine-based polycarboxylic acid can exert the maximum effect. Even the indium oxalate dissolving agent of the present invention containing an amine-based polycarboxylic acid amine salt must be adjusted within a pH range in which the chelating agent exerts the maximum effect. The amount of the alkaline aqueous solution to be added is preferably such that the pH is in the range of 9 to 11, more preferably in the range of 10 to 11. When the pH is less than 9, a sufficient chelation effect cannot be obtained, and the amount of indium oxalate dissolved is extremely small. Moreover, as the pH approaches 1, the amount of dissolution of the chelating agent itself decreases and precipitates in the solution. When the pH is more than 11, a sufficient sequestration effect cannot be obtained, and the amount of indium oxalate dissolved is extremely small and uneconomical.

A preferred method of using the indium oxalate dissolving agent of the present invention is a method in a wet etching apparatus system for cleaning a transparent conductive film made of an indium tin oxide (ITO) film or an indium zinc oxide (IZO) film. First, the ITO etching solution is completely discharged in a wet etching apparatus system of a transparent conductive film composed of an indium tin oxide (ITO) film or an indium zinc oxide (IZO) film, and is repeatedly washed and discharged by circulation of water or hot water. Until the pH becomes neutral. Next, the indium oxalate dissolving agent of the present invention is placed in an etching apparatus system, and is circulated and washed for 4 hours or more. After the completion of the washing, the indium oxalate dissolving agent is discharged, and finally washed with water or hot water.

The temperature of the washing may be any ° C as long as it can dissolve indium oxalate, and is preferably 30 to 50 ° C, more preferably about 40 ° C from the viewpoint of solubility.

By using the cleaning method of the present invention, it is possible to dissolve indium oxalate at a position selected by one or more selected positions in a pipe, a valve, a filter, a pump, a nozzle, a substrate transfer roller, an inner wall of a wet etching chamber, and a buffer tank. Remove.

Since the solvent of the present invention has a relatively high solubility of indium oxalate, it is possible to easily recover indium of a rare metal from the cleaning liquid used in the present invention.

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the examples.

Example

Relationship between alkali component concentration and dissolved amount of indium oxalate

Table 1 shows the relationship between the pH caused by ethylenediaminetetraacetic acid and ammonia, and the amount of indium oxalate dissolved. The indium oxalate dissolving agent was prepared by adding a raw material and water in a ratio as shown in Table 1 and stirring until the chelating agent was completely dissolved. In the amount of indium oxalate dissolved, the prepared indium oxalate dissolving agent was heated to 40 ° C, and after indium oxalate was added to the dissolving agent, the mixture was stirred for 4 hours, and the solubility was examined.

It can be seen from Table 1 that as the ammonia concentration increases, the pH also tends to rise. On the other hand, the amount of indium oxalate dissolved shows a maximum value in the range of pH of about 10.0 to 11.0, that is, an ammonia concentration of 5.0 to 10.0% by weight.

Comparative example 1

As is clear from Table 1 and Comparative Example 1, it was found that a raw material and water were added so that ethylenediaminetetraacetic acid was 5.0% by weight, and the composition was not contained in ammonia, but the solubility of the chelating agent itself in water was low. Can't dissolve it.

As is clear from Comparative Example 1, the dissolved ethylenediaminetetraacetic acid must be an alkaline solution such as ammonia water.

Relationship between concentration of chelating agent and dissolved amount of indium oxalate

Table 2 shows that the ammonia addition concentration was fixed in Example 2 of Table 1. The value of 5.0% by weight of the maximum amount of dissolved indium oxalate is changed, and the change in the pH and the amount of dissolved indium oxalate when the amount of ethylenediaminetetraacetic acid is added is increased or decreased.

As is clear from Table 2, when the amount of the chelating agent, that is, the amount of ethylenediaminetetraacetic acid added, the amount of dissolved indium oxalate tends to increase.

Ethylenediamine tetraacetate chelating agent

Table 3 shows the change in pH and the amount of indium oxalate dissolved when the ammonia was fixed at 5.0% by weight and the amount of ethylenediaminetetraacetic acid ammonium salt added was decreased or decreased. The indium oxalate dissolving agent was prepared by adding a raw material and water so as to have a ratio of Table 3, and stirring until the chelating agent was completely dissolved. In the amount of indium oxalate dissolved, the prepared indium oxalate dissolving agent was heated to 40 ° C, and after indium oxalate was added to the dissolving agent, the mixture was stirred for 4 hours, and the solubility was examined.

As is clear from Table 3, even in the case of using ethylenediaminetetraacetate ammonium salt, the indium oxalate dissolution effect was obtained. Further, when the amount of the chelating agent, that is, the amount of the ethylenediaminetetraacetic acid ammonium salt added, the amount of dissolved indium oxalate tends to increase.

Table 4 shows the relationship between the pH of ethylenediaminetetraacetic acid amine salt and ammonia and the amount of indium oxalate dissolved. Ethylenediaminetetraacetic acid amine salts are commercially available from a large number of chelating agent manufacturers. For example, it is marketed by Chelest Co. under the trade names of Chelest M, Chelest M-50, and Chelest OH. Among them, Chhelest M-50 is particularly excellent because of its large chelation effect and easy preparation of a dissolving agent because it is in the form of a solution.

The indium oxalate dissolving agent was prepared by adding a raw material and water so as to have a ratio of Table 4, and stirring until the chelating agent was completely dissolved. In the amount of indium oxalate dissolved, the prepared indium oxalate dissolving agent was heated to 40 ° C, and after indium oxalate was added to the dissolving agent, the mixture was stirred for 4 hours, and the solubility was examined.

As is clear from Table 4, even when ethylenediaminetetraacetic acid amine salt was used, the indium oxalate dissolution effect was obtained. Further, when the amount of the chelating agent, that is, the amount of Chelest M-50 added, the amount of dissolved indium oxalate tends to increase.

a chelating agent other than ethylenediaminetetraacetic acid

The solvent was prepared by dissolving 5.0% by weight of trans-1,2-cyclohexanediaminetetraacetic acid and 7.0% by weight of ammonia in water. The pH of the solution was 10.1.

The prepared dissolving agent was heated to 40 ° C, and indium oxalate was added to the dissolving agent, followed by stirring for 4 hours, and the solubility was investigated. As a result, up to 2.9% by weight of indium oxalate was dissolved.

From this result, it is understood that even in the case of using a chelating agent other than ethylenediaminetetraacetic acid, the indium oxalate dissolving effect is obtained.

Effect of an amine salt as an additional chelating agent

In the composition using ethylenediaminetetraacetic acid as a chelating agent, Chelest M-50 of ethylenediaminetetraacetic acid amine salt was added as an additional chelating agent. Ethylenediaminetetraacetic acid was 5.0% by weight, Chhelest M-50 was 5.0% by weight, and ammonia was 5.0% by weight dissolved in water. The pH of the solution was 10.2.

The prepared dissolving agent was heated to 40 ° C, and indium oxalate was added to the dissolving agent, followed by stirring for 4 hours, and the solubility was investigated. As a result, at most 5% by weight of indium oxalate can be dissolved.

By using ethylenediaminetetraacetic acid and ethylenediaminetetraacetic acid amine salt in combination, the maximum dissolution amount of indium oxalate is increased.

Industrial availability

As described above, in the past, the insoluble oxalate is removed by the use of a strong water flow of water or hot water, and the dissolving agent composition of the present invention shows that the indium oxalate can be chemically dissolved and removed. Excellent cleaning effect.

Claims (11)

A solvent composition characterized in that it is used for dissolving and removing indium oxalate precipitated in an etching apparatus system, the solvent composition comprising an alkali component, at least one compound selected from the group consisting of amine polycarboxylic acids, and An aqueous solution selected from at least one compound of an amine polycarboxylate amine salt. For example, the solvent composition of the first aspect of the patent application has a pH in the range of 9-11. The solvent composition according to claim 1 or 2, wherein a compound selected from the group consisting of an amine polycarboxylic acid and a compound selected from the group consisting of an amine polycarboxylic acid amine salt has a total concentration of 1 to 40% by weight. The solvent composition of claim 1 or 2, wherein the concentration of the compound selected from the group consisting of the amine polycarboxylic acid is from 1 to 20% by weight, and the concentration of the compound selected from the amine group of the amine polycarboxylate is 1 to 20% by weight. The solvent composition of claim 1 or 2, wherein the amine polycarboxylic acid is selected from the group consisting of ethylenediamine diacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and triamethylenetetraamine hexaacetic acid. , trans-1,2-cyclohexanediaminetetraacetic acid. The solvent composition of claim 1 or 2, wherein the amine polycarboxylate amine salt is ethylenediamine diacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and triamethylenetetraamine hexaacetic acid. An amine salt of trans-1,2-cyclohexanediaminetetraacetic acid. The solvent composition according to claim 1 or 2, wherein the alkali component is any one of ammonia, sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide. A cleaning method in an etching apparatus system, comprising the steps of: (1) removing the etching liquid from the etching apparatus system, washing the water to a pH to be neutral; (2) using the patent application scope a solvent composition of any one of items 1 to 7, which chemically dissolves and removes the indium oxalate precipitated in the apparatus; and (3) After removing the solvent, it is washed with water until the pH becomes neutral. The cleaning method in the etching apparatus system according to the eighth aspect of the invention, which further comprises the dissolving agent composition according to any one of claims 1 to 7, which is used in the dissolution and removal step. A cleaning method in an etching apparatus system according to claim 8, wherein the etching apparatus is a wet etching apparatus of a transparent conductive film composed of an ITO film or an IZO film. A cleaning method in an etching apparatus system according to claim 8 which dissolves and removes one selected from the group consisting of a pipe, a valve, a filter, a pump, a nozzle, a substrate conveying roller, an inner wall of a wet etching chamber, and a buffer tank. Or indium oxalate precipitated at two or more locations.