JP2021105174A - Cleaner as well as methods for producing flat panel display substrate and semiconductor device substrate - Google Patents

Abstract

To provide a cleaner that has low corrosiveness to metal, is less likely to foam during cleaning, can prevent metal contamination of a substrate, and has no limitation in terms of pH when in use, and methods for producing a flat panel display substrate and a semiconductor device substrate.SOLUTION: A cleaner in the present invention has an aniline polymer that has a unit represented by general formula (1) with the content ratio of an acidic group to an aromatic ring being 80 mol% or more, and water. In formula (1), R1-R4 are independently selected from the group consisting of a hydrogen atom, a C1-24 linear or branched alkyl group, a C1-24 linear or branched alkoxy group, an acidic group, a hydroxy group, a nitro group, and a halogen atom. At least one of R1-R4 is an acidic group, where the acidic group is a sulfonic acid group or a carboxy group.SELECTED DRAWING: None

Description

The present invention relates to a cleaning agent suitable for cleaning a flat panel display substrate, a semiconductor device substrate, and the like, and a method for manufacturing a flat panel display substrate and a semiconductor device substrate.

In the manufacturing process of a flat panel display (FPD), a metal film and a resist film to be used as wiring are sequentially formed on a substrate such as glass, and then the resist film is exposed, developed, and patterned to form a resist pattern. Is being done. After the resist pattern is formed, the portion without the resist is selectively etched, and the metal shavings and the resist film generated by the etching are removed to obtain a substrate on which the resist pattern is formed.

In a semiconductor device, a metal film or the like to be a wiring is formed on a substrate such as a silicon wafer, and then the surface is flattened by chemical mechanical polishing (CMP) using an abrasive to flatten the surface. Manufactured by stacking new layers on top.
Since the abrasives and metal polishing debris used in the CMP process tend to remain on the surface of the substrate after the CMP process, it is necessary to clean the substrate.

Conventionally, a cleaning agent containing an anionic surfactant has been used for cleaning FPD substrates and semiconductor device substrates.
However, the cleaning agent containing an anionic surfactant may corrode the metal film formed on the substrate. In addition, there is also a problem that bubbles are easily foamed during cleaning and the bubbles remain on the substrate.

Therefore, as a detergent that does not easily foam, for example, Patent Document 1 describes sulfamic acid, an anionic surfactant having a sulfonic acid group in the molecule and having a mass average molecular weight of 1000 to 2000000, a chelating agent, and water. Detergents containing and having a pH of 3 or less are disclosed.
Further, as a detergent containing no surfactant, for example, Patent Document 2 discloses a detergent containing aminobenzenesulfonic acid, a water-miscible organic solvent, and water and having a pH of 6 to 11. ing.

JP-A-2010-163609 JP-A-2009-224782

However, although the cleaning agent described in Patent Document 1 uses a high molecular weight anionic surfactant, it is relatively difficult to foam, but it does not necessarily satisfy the foaming prevention property and is also inferior in corrosion prevention property. In addition, there was a pH restriction at the time of use.
On the other hand, since the cleaning agent described in Patent Document 2 does not contain an anionic surfactant, it is difficult to foam and has low corrosiveness to metals, but there is a pH restriction at the time of use.

Further, sulfamic acid contained in the detergent described in Patent Document 1 and aminobenzenesulfonic acid contained in the detergent described in Patent Document 2 are likely to be mixed with an alkali metal such as sodium during production. As a result, sulfamic acid and aminobenzenesulfonic acid are blended in the detergent in a state containing the alkali metal, and the alkali metal released into water adheres to the substrate.
As described above, the cleaning agents described in Patent Documents 1 and 2 also have a problem of metal contamination on the substrate. In order to prevent metal contamination of the substrate, the alkali metal mixed in sulfamic acid or aminobenzenesulfonic acid may be removed. However, since aminobenzenesulfonic acid is particularly difficult to dissolve in water, it is difficult to purify it with an ion exchange resin or the like, and it is difficult to remove the mixed alkali metal.

The present invention has been made in view of the above circumstances, and is a cleaning agent having low corrosiveness to metals, less likely to foam during cleaning, preventing metal contamination of the substrate, and having no pH restriction during use, and a flat panel display substrate. And a method for manufacturing a semiconductor device substrate.

The present invention has the following aspects.
[1] A cleaning agent containing water and an aniline-based polymer having a unit represented by the following general formula (1) and having an acidic group content of 80 mol% or more with respect to an aromatic ring.
[2] The cleaning agent according to [1], wherein the alkali metal content is 1 mass ppm or less.
[3] The cleaning agent according to [1] or [2], wherein the aniline-based polymer has a structure represented by the following general formula (3).
[4] The aniline-based polymer is at least one of poly (2-sulfo-5-methoxy-1,4-iminophenylene) and poly (2-methoxyaniline-5-sulfonic acid), according to [3]. Cleaning agent.

In the formula (1), R ^{1 to} R ⁴ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, and acidic groups. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 1 to} R ⁴ is an acidic group. Here, the acidic group is a sulfonic acid group or a carboxy group.
In the formula (3), R ^{12 to} R ²⁷ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, or an acidic group. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 12 to} R ²⁷ is an acidic group. Further, n indicates the degree of polymerization.

[5] The cleaning agent according to any one of [1] to [4], which is for a flat panel display substrate or a semiconductor device substrate.
[6] A flat panel in which at least one of metal shavings and a resist film generated by etching is removed by the cleaning agent according to any one of [1] to [4] in the process of manufacturing a flat panel display substrate. How to manufacture a display board.
[7] In the process of manufacturing a semiconductor device substrate, at least one of a metal polishing residue and an abrasive generated by chemical mechanical polishing is removed by the cleaning agent according to any one of [1] to [4]. , Manufacturing method of semiconductor device substrate.

According to the present invention, a cleaning agent having low corrosiveness to metals, less likely to foam during cleaning, preventing metal contamination of the substrate, and having no pH restriction during use, and a method for manufacturing a flat panel display substrate and a semiconductor device substrate. Can be provided.

Hereinafter, the present invention will be described in detail.
In the present invention, "cleaning" includes not only removing objects to be cleaned (for example, metal shavings, polishing debris, abrasives, etc.), but also removing (peeling) a resist film, for example.
Further, in the present invention, "water-soluble" and "soluble" mean that 0.1 g or more is uniformly dissolved in water or 10 g (liquid temperature 25 ° C.) of a mixed solvent of water and a water-soluble organic solvent. do.

[Washing soap]
The cleaning agent of the present invention contains an aniline-based polymer having an acidic group and water.

<Aniline polymer>
Aniline-based polymers have acidic groups. Aniline-based polymers are water-soluble and have excellent solubility in water.
The term "acidic group" is a sulfonic acid group _(-SO 3 H) or carboxyl group (-COOH).
Note that the sulfonic acid group, or a substituent having a sulfonic acid group (-R 5 ^SO 3 _H), alkali metal salts of sulfonic acid groups, ammonium salts or the like substituted ammonium salts, are also included.
On the other hand, the carboxy group also includes a substituent having a carboxy group (-R ⁵ COOH), an alkali metal salt of the carboxy group, an ammonium salt, a substituted ammonium salt and the like.
The R ⁵ represents a linear or branched alkylene group having 1 to 24 carbon atoms, an arylene group or an aralkylene group.

The aniline-based polymer is not particularly limited as long as it has an acidic group, and known aniline-based polymers can be used.
Specifically, any of the following (i) to (iii) is placed on the skeleton of a π-conjugated polymer such as polyaniline or polydiaminoanthraquinone having an unsubstituted or substituent or on a nitrogen atom in the π-conjugated polymer. Examples include polymers having.
(I) Acidic group (ii) Alkali metal salt, ammonium salt or substituted ammonium salt of acidic group (iii) Alkali metal salt of acidic group, acidic group, ammonium salt or alkyl group substituted with any of substituted ammonium salt Alkyl group containing ether bond

Among these, a polymer containing a polyaniline skeleton is preferable from the viewpoint of excellent solubility in water.
In particular, from the viewpoint of exhibiting high solubility, a polymer containing 20 to 100 mol% of the units represented by the following general formula (2) in all the units (100 mol%) constituting the polymer is preferable.

式（２）中、Ｒ^６〜Ｒ^１０は各々独立に、水素原子、炭素数１〜２４の直鎖もしくは分岐のアルキル基、炭素数１〜２４の直鎖もしくは分岐のアルコキシ基、酸性基、ヒドロキシ基、ニトロ基、ハロゲン原子、−Ｎ(Ｒ^１１)_２、−ＮＨＣＯＲ^１１、−ＳＲ^１１、−ＯＣＯＲ^１１、−ＣＯＯＲ^１１、−ＣＯＲ^１１、−ＣＨＯ、および−ＣＮからなる群より選ばれ、Ｒ^１１は炭素数１〜２４の直鎖もしくは分岐のアルキル基、アリール基またはアラルキル基を表す。
ただし、Ｒ^６〜Ｒ^１０のうちの少なくとも１つは酸性基である。

In formula (2), R ^{6 to} R ¹⁰ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, acidic groups, and the like. Selected from the group consisting of hydroxy group, nitro group, halogen atom, -N (R ¹¹ ) ₂ , -NHCOR ¹¹ , -SR ¹¹ , -OCOR ¹¹ , -COOR ¹¹ , -COR ^{11, -CHO, and -CN.} R ¹¹ represents a linear or branched alkyl group, aryl group or alkoxy group having 1 to 24 carbon atoms.
However, ^{at least one of R 6 to} R ¹⁰ is an acidic group.

As the aniline-based polymer, among the polymers having a unit represented by the general formula (2), a polymer having a unit represented by the following general formula (1) is preferable from the viewpoint of being more excellent in solubility in water.

In the formula (1), R ^{1 to} R ⁴ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, and acidic groups. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 1 to} R ⁴ is an acidic group.
A sulfonic acid group is preferable as the acidic group.

As the unit represented by the general formula (1) ^{, any one of R 1 to} R ⁴ is a linear or branched alkoxy group having 1 to 4 carbon atoms because it is easy to manufacture, and the other. It is preferable that any one of the above is a sulfonic acid group and the rest is a hydrogen atom.

From the viewpoint of excellent solubility in water regardless of pH, the aniline-based polymer contains 10 to 100 mol% of the units represented by the general formula (1) among all the units (100 mol%) constituting the aniline-based polymer. It is preferably contained, more preferably 50 to 100 mol%, and particularly preferably 100 mol%.
Further, the aniline-based polymer preferably contains 10 or more units represented by the general formula (1) in one molecule.

Further, from the viewpoint of improving solubility, the aniline-based polymer preferably has an acidic group content of 70 mol% or more with respect to the aromatic ring, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. preferable.

Further, the aniline-based polymer is a constituent unit other than the unit represented by the general formula (1), and is substituted or unsaturated aniline, thiophene, pyrrole, phenylene, vinylene, diylene, as long as it does not affect solubility or the like. It may contain one or more units selected from the group consisting of valent unsaturated groups and divalent saturated groups.

As the aniline-based polymer, a compound having a structure represented by the following general formula (3) is preferable from the viewpoint of exhibiting high solubility.

In the formula (3), R ^{12 to} R ²⁷ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, or an acidic group. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 12 to} R ²⁷ is an acidic group. Further, n indicates the degree of polymerization.

Among the compounds having the structure represented by the general formula (3), poly (2-sulfo-5-methoxy-1,4-iminophenylene) and poly (2-methoxyaniline-5) are excellent in solubility. -Sulfonic acid) is particularly preferable.

The mass average molecular weight of the aniline polymer is preferably 3000 to 1000000, more preferably 5000 to 80000, and particularly preferably 1000 to 70000.
Here, the mass average molecular weight of the aniline-based polymer is the mass average molecular weight (in terms of sodium polystyrene sulfonate) measured by gel permeation chromatography (GPC).

(Manufacturing method of aniline polymer)
The aniline polymer can be produced by a known method. For example, at least one compound (monomer) selected from the group consisting of an acidic group-substituted aniline, an alkali metal salt thereof, an ammonium salt and a substituted ammonium salt is polymerized using an oxidizing agent in the presence of a basic reaction aid. It can be obtained by.

Examples of the acidic group-substituted aniline include a sulfonic acid group-substituted aniline having a sulfonic acid group as an acidic group.
Typical sulfonic group-substituted anilines are aminobenzene sulfonic acids, specifically 2-aminobenzene sulfonic acid, 3-aminobenzene sulfonic acid, 4-aminobenzene sulfonic acid, aniline-2,6-disulfone. Acids, aniline-2,5-disulfonic acid, aniline-3,5-disulfonic acid, aniline-2,4-disulfonic acid, aniline-3,4-disulfonic acid and the like are preferably used.

Examples of the sulfon group-substituted aniline other than aminobenzene sulfonic acids include methyl aminobenzene sulfonic acid, ethylaminobenzene sulfonic acid, n-propylaminobenzene sulfonic acid, iso-propylaminobenzene sulfonic acid, n-butylaminobenzene sulfonic acid, and the like. Alkyl group-substituted aminobenzene sulfonic acids such as sec-butylaminobenzene sulfonic acid and t-butyl aminobenzene sulfonic acid; methoxyaminobenzene sulfonic acid (for example, 2-methoxyaniline-5-sulfonic acid, 2-methoxyaniline-3-sulfon) Acids, 3-methoxyaniline-2-sulfonic acid, 3-methoxyaniline-5-sulfonic acid, etc.), ethoxyaminobenzenesulfonic acid, propoxyaminobenzenesulfonic acid and other alkoxy group-substituted aminobenzenesulfonic acids; Sulfonic acids; nitro group-substituted aminobenzene sulfonic acids; halogen-substituted aminobenzene sulfonic acids such as fluoroaminobenzene sulfonic acid, chloroaminobenzene sulfonic acid, and bromaminobenzene sulfonic acid can be mentioned.
Among these, alkyl group-substituted aminobenzene sulfonic acids, alkoxy group-substituted aminobenzene sulfonic acids, hydroxy group-substituted aminobenzene sulfonic acids, or halogen-substituted aminobenzene sulfones are obtained in that an aniline-based polymer having particularly excellent solubility can be obtained. Alkoxy group-substituted aminobenzenesulfonic acids, alkali metal salts thereof, ammonium salts and substituted ammonium salts thereof are particularly preferable because acids are preferable and production is easy.
Each of these sulfonic acid group-substituted anilines may be used alone, or two or more thereof may be mixed and used in an arbitrary ratio.

As the basic reaction aid used in the production of the aniline-based polymer, for example, inorganic bases, ammonia, aliphatic amines, cyclic saturated amines, cyclic unsaturated amines and the like are used.
The basic reaction aid is preferably an inorganic base, and specific examples thereof include sodium hydroxide, potassium hydroxide, and lithium hydroxide.
In addition to inorganic bases, fatty amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, and diethylmethylamine; pyridine, α-picoline, β-picoline, and γ -Cyclic unsaturated amines such as picoline are preferably used as basic reaction aids.
Each of these basic reaction aids may be used alone or in admixture of two or more at any ratio.

The oxidizing agent used for producing the aniline-based polymer is not limited as long as it has a standard electrode potential of 0.6 V or more, but for example, peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and peroxodisulfuric acid are used. Peroxodisulfuric acid such as potassium; it is preferable to use hydrogen peroxide or the like.
Each of these oxidizing agents may be used alone or in combination of two or more at an arbitrary ratio.

Examples of the polymerization method include a method of dropping a mixed solution of a monomer and a basic reaction aid into an oxidizing agent solution, a method of dropping an oxidizing agent solution into a mixed solution of a monomer and a basic reaction aid, a reaction vessel, and the like. Examples thereof include a method of simultaneously dropping a mixed solution of a monomer and a basic reaction aid and an oxidizing agent solution.

After the polymerization, the solvent is usually separated by filtration using a centrifuge or the like. Further, if necessary, the filtrate is washed with a washing liquid and then dried to obtain a polymer (aniline-based polymer).

Alkali metals such as sodium are likely to be mixed in monomers such as acidic group-substituted aniline, which are raw materials for aniline-based polymers, during production. It is considered that this is because the alkali metal is incorporated into the monomer as a counter ion of an acidic group. Therefore, the alkali metal is also contained in the aniline-based polymer obtained by polymerizing the monomer mixed with the alkali metal. This alkali metal may be released into the cleaning liquid and adhere to the substrate when cleaning the FPD substrate or the semiconductor device substrate, which causes metal contamination of the substrate.

However, since the aniline-based polymer used in the present invention has excellent solubility in water and water-soluble organic solvents, it can be easily purified.
Since the purified aniline-based polymer is sufficiently depleted of alkali metals, it is possible to prevent metal contamination of the substrate when used as a detergent.

The method for purifying the aniline-based polymer is not particularly limited, and any method such as an ion exchange method, acid washing in a protonic acid solution, removal by heat treatment, and neutralization precipitation can be used, but the ion exchange method is particularly effective. Is.
By using the ion exchange method, the alkali metal mixed in the aniline-based polymer can be effectively removed, and a highly pure aniline-based polymer can be obtained.

Examples of the ion exchange method include a column type or batch type treatment using a cation exchange resin; an electrodialysis method and the like.
When removing the alkali metal by the ion exchange method, the aniline-based polymer obtained by the polymerization is dissolved in an aqueous medium so as to have a desired solid content concentration, and the polymer solution is contacted with a cation exchange resin or the like. Is preferable.
The concentration of the aniline-based polymer in the polymer solution is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, from the viewpoint of industriality and purification efficiency.

Examples of the aqueous medium include water, a water-soluble organic solvent, and a mixed solvent of water and a water-soluble organic solvent. The water-soluble organic solvent is an organic solvent soluble in water, for example, alcohols such as methanol, ethanol, 2-propanol, 1-propanol and 1-butanol; and ketones such as acetone, methyl ethyl ketone, ethyl isobutyl ketone and methyl isobutyl ketone. Classes; ethylene glycols such as ethylene glycol, ethylene glycol methyl ether and ethylene glycol mono-n-propyl ether; propylene glycols such as propylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether and propylene glycol propyl ether. Amidos such as dimethylformamide and dimethylacetamide; Pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone; Hydroxylesters such as methyl lactate, ethyl lactate, methyl β-methoxyisobutyrate and methyl α-hydroxyisobutyrate Can be mentioned.

As the cation exchange resin, a commercially available product can be used, and for example, a strong acid type cation exchange resin such as "Amberlite" manufactured by Organo Corporation is preferable.
The form of the cation exchange resin is not particularly limited, and various forms can be used, and examples thereof include spherical fine particles, a film form, and a fibrous form.
The amount of the cation exchange resin with respect to the aniline-based polymer is preferably 100 to 2000 parts by mass, more preferably 500 to 1500 parts by mass with respect to 100 parts by mass of the aniline-based polymer. If the amount of the cation exchange resin is less than 100 parts by mass, it is difficult to sufficiently remove the alkali metal. On the other hand, if the amount of the cation exchange resin exceeds 2000 parts by mass, the amount becomes excessive with respect to the polymer solution, so that it is difficult to recover the polymer solution after contacting with the cation exchange resin and performing the cation exchange treatment. Become.

Examples of the method of contacting the polymer solution with the cation exchange resin include a method in which the polymer solution and the cation exchange resin are placed in a container and stirred or rotated to bring them into contact with the cation exchange resin.
Further, a method in which a column is filled with a cation exchange resin and a polymer solution is passed through the column at a flow rate of preferably SV = 0.01 to 20, more preferably SV = 0.2 to 10, to perform a cation exchange treatment. But it may be.
Here, the space velocity SV (1 / hr) = flow rate (m ³ / hr) / filter medium amount (volume: m ³ ).

The time for contacting the polymer solution with the cation exchange resin is preferably 0.1 hours or more, more preferably 0.5 hours or more, from the viewpoint of purification efficiency.
The upper limit of the contact time is not particularly limited, and may be appropriately set according to conditions such as the concentration of the polymer solution, the amount of the cation exchange resin, and the contact temperature described later.
From an industrial point of view, the temperature at which the polymer solution and the cation exchange resin are brought into contact is preferably 10 to 50 ° C, more preferably 10 to 30 ° C.

In the case of the electrodialysis method, the ion exchange membrane of the electrodialysis method is not particularly limited, but an ion exchange membrane that has been subjected to a treatment for selectively permeating monovalent ions in order to further suppress permeation due to diffusion of impurities. It is preferable to use one having a fractionated molecular weight of 300 or less. As such an ion exchange membrane, for example, "Neocepta CMK (cation exchange membrane, molecular weight cut-off 300)" and "Neocepta AMX (anion exchange membrane, molecular weight cut-off 300)" manufactured by Astom Co., Ltd. are suitable. Further, as the ion exchange membrane used in the electrodialysis method, a bipolar membrane which is an ion exchange membrane having a structure in which an anion exchange layer and a cation exchange layer are laminated may be used. As such a bipolar film, for example, "PB-1E / CMB" manufactured by Astom Co., Ltd. is suitable. The current density in electrodialysis is preferably equal to or less than the critical current density. The applied voltage of the bipolar film is preferably 10 to 50 V, more preferably 25 to 35 V.

Alkali metals are sufficiently removed from the aniline-based polymer purified in this manner.
The purified aniline polymer is in a state of being dissolved in an aqueous medium such as water. Therefore, a solid aniline-based polymer can be obtained by removing the aqueous medium with an evaporator or the like, but the aniline-based polymer may be used as a cleaning agent in a state of being dissolved in the aqueous medium.

The content of the aniline-based polymer in the detergent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and 1% by mass, in terms of pure content (solid content), based on the total mass of the cleaning agent. % Or more is more preferable. When the content of the aniline-based polymer is 0.1% by mass or more, the FPD substrate, the semiconductor device substrate, and the like can be sufficiently cleaned.
The content of the aniline-based polymer in the cleaning agent is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less, based on the pure content (solid content conversion). preferable.

<Water>
Examples of water include tap water, ion-exchanged water, pure water, distilled water and the like.
When the aniline polymer is purified using water as an aqueous medium and the purified aniline polymer is used as it is dissolved in water, the content of the aniline polymer in the detergent should be within the above range. , May be concentrated or diluted with water.

The content of water in the cleaning agent is preferably 80 to 99.9% by mass, more preferably 85 to 99.5% by mass, still more preferably 90 to 99% by mass, based on the total mass of the cleaning agent.
The total content of the aniline polymer and water contained in the cleaning agent shall not exceed 100% by mass with respect to the total mass of the cleaning agent.

<Arbitrary ingredient>
The cleaning agent may contain components (optional components) other than the aniline polymer and water.
Examples of the optional component include an organic solvent and various additives.

As the organic solvent, a water-soluble organic solvent soluble in water is preferable. Examples of the water-soluble organic solvent include the water-soluble organic solvent exemplified above as the aqueous medium in the description of purification of the aniline-based polymer.
The content of the organic solvent in the cleaning agent is preferably 1 to 99% by mass, more preferably 3 to 95% by mass, still more preferably 5 to 90% by mass, based on the total mass of the cleaning agent.

Examples of the additive include known additives contained in detergents used for cleaning FPD substrates, semiconductor device substrates, etc. Specific examples thereof include antioxidants, rust inhibitors, pH adjusters, buffers, and defoamers. Examples include foaming agents, preservatives and hydrotropes.
Considering the prevention of corrosion and foaming of the metal film during cleaning of the FPD substrate and the semiconductor device substrate, it is preferable that the cleaning agent does not substantially contain a surfactant such as an anionic surfactant. Here, "substantially free" means 0.1% by mass or less with respect to the total mass of the cleaning agent.

When the cleaning agent contains an optional component, the total content of the aniline polymer, water and the optional component contained in the cleaning agent shall not exceed 100% by mass with respect to the total mass of the cleaning agent.

<Detergent manufacturing method>
The cleaning agent of the present invention can be produced by mixing the above-mentioned aniline-based polymer, water, and if necessary, an arbitrary component.
Further, as described above, since the purified aniline-based polymer is in a state of being dissolved in an aqueous medium, the purified aniline-based polymer dissolved in the aqueous medium may be used as it is as a detergent, or if necessary. It may be concentrated as a detergent, diluted with water, or added with an arbitrary component to make a detergent.

The cleaning agent thus obtained has a sufficiently reduced alkali metal content. The content of the alkali metal in the detergent is preferably 1 mass ppm or less, more preferably 0.95 mass ppm or less, still more preferably 0.9 mass ppm or less, based on the total mass of the detergent. The smaller the content of the alkali metal in the cleaning agent, the more preferable, and the lower limit value is preferably 0 mass ppm.
Here, the content of the alkali metal in the cleaning agent is determined by metal analysis using a high frequency inductively coupled plasma mass spectrometer (ICP-MS).

<Effect>
The cleaning agent of the present invention described above contains an aniline-based polymer having an acidic group and water.
Alkali metals such as sodium are likely to be mixed into the monomer that is the raw material of the aniline-based polymer having an acidic group during production. Since the monomer is difficult to dissolve in water, it is difficult to purify it, and it is difficult to remove alkali metals. This alkali metal may be released into the cleaning liquid and adhere to the substrate when cleaning the FPD substrate or the semiconductor device substrate, which causes metal contamination on the substrate.

However, the aniline-based polymer having an acidic group contained in the detergent of the present invention is water-soluble and has excellent solubility in water or a water-soluble organic solvent. Therefore, it can be easily purified by an ion exchange method or the like, and the alkali metal can be sufficiently removed. Therefore, the cleaning agent of the present invention tends to have a sufficiently reduced alkali metal content, and can prevent metal contamination of the substrate.

Moreover, since the cleaning agent of the present invention does not need to contain a surfactant, it does not easily foam and has low corrosiveness to metals.

Further, as described above, the conventional cleaning agent has a pH restriction at the time of use. For example, in the detergent described in Patent Document 2, it is considered necessary to adjust the pH to 6 to 11 in order to dissolve the monomer aminobenzenesulfonic acid in water.
However, since the aniline-based polymer having an acidic group contained in the detergent of the present invention is water-soluble, it can be dissolved in water without adjusting the pH. Therefore, the cleaning agent of the present invention can be used not only in an alkaline state but also in an acidic state, and there is no pH restriction at the time of use.

<Use>
The cleaning agent of the present invention can be used as a cleaning agent for cleaning electronic materials.
Examples of the electronic material to be cleaned (object to be cleaned) include an FPD substrate, a semiconductor device substrate, a magnetic disk substrate, a photomask substrate, a solar cell substrate, a printed circuit board, and electronic components. Among these, the cleaning agent of the present invention is suitable as a cleaning agent for FPD substrates and semiconductor device substrates.

For example, when the cleaning agent of the present invention is used for an FPD substrate, it is applied as a cleaning agent used in a cleaning process for the purpose of removing metal shavings and resist film generated by etching in the FPD manufacturing process. Is preferable.
When the cleaning agent of the present invention is used for a semiconductor device substrate, it is applied as a cleaning agent used in a cleaning process for the purpose of removing metal polishing debris and abrasives generated by CMP in the semiconductor device manufacturing process. Is preferable.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of the present invention.
The various measurement / evaluation methods in Examples and Comparative Examples are as follows.

<Measurement / evaluation method>
(Measurement of alkali metal content)
The sodium ion content relative to the total mass of the cleaning agent was measured using ICP-MS.

(Evaluation of corrosion prevention)
As a test piece, an aluminum base material (ISO 7075-T6 equivalent) that had been degreased and surface-polished in advance was used. The mass and material density of the test piece were measured.
The test piece was immersed in 100 parts by mass of the cleaning agent, held at 55 ° C. ± 1 ° C. for 7 days, and then the test piece was taken out from the cleaning agent. The cleaning agent adhering to the test piece was removed, the test piece was dried, and then the mass of the test piece was measured. This was taken as the mass of the test piece after immersion, and the degree of erosion of the test piece was determined from the following formula (I).
X = {(W _1- W ₂ ) x 10 x 365)} / (d x S x T) ... (I)
(In the formula (I), "X" is the erosion degree [mm / year] of the test piece, "W ₁ " is the mass [g] of the test piece before being immersed in the cleaning agent, and "W ₂ ". Is the mass [g] of the test piece after immersion, “d” is the material density [g / cm ² ] of the test piece before immersion in the cleaning agent, and “S” is the immersion area [cm] of the test piece. ² ], and "T" is the number of days of immersion (number of days of retention).)

The corrosion resistance to metal was evaluated according to the following evaluation criteria.
◯: The degree of erosion is less than 6.25 mm / year.
X: The degree of erosion is 6.25 mm / year or more.

(Evaluation of foaming prevention)
10 g of the cleaning agent was put into a 30 mL glass sample bottle, shaken vigorously for 30 seconds, and then left for 1 minute. The state of the foam after being left to stand was visually observed, and the foaming prevention property was evaluated according to the following evaluation criteria.
◯: Bubbles cannot be confirmed.
X: Bubbles are confirmed.

(Evaluation of metal pollution prevention)
A silicon wafer was used as the object to be cleaned.
The object to be cleaned was immersed in 100 parts by mass of the cleaning agent, held at 25 ° C. for 2 hours, and then the object to be cleaned was taken out from the detergent. After removing the cleaning agent adhering to the object to be cleaned and drying the object to be cleaned, the object to be cleaned was immersed in 100 parts by mass of ultrapure water and held at 25 ° C. for 12 hours. The content of sodium ions with respect to the total mass of ultrapure water after holding was measured using ICP-MS, and the metal contamination prevention property was evaluated according to the following evaluation criteria.
◯: The content of sodium ions in ultrapure water is less than 1 mass ppm.
X: The content of sodium ions in ultrapure water is 1 mass ppm or more.

"Example 1"
<Manufacturing of aniline-based polymers with acidic groups>
100 mmol of 2-methoxyaniline-5-sulfonic acid was dissolved in 300 mL of a triethylamine solution (solvent: water / acetonitrile = 5/5) having a concentration of 4 mol / L at 25 ° C. to obtain a monomer solution.
Separately, 100 mmol of ammonium peroxodisulfate was dissolved in a solution of water / acetonitrile = 5/5 to obtain an oxidizing agent solution.
Then, the oxidizing agent solution was added dropwise to the monomer solution. After completion of the dropping, the mixture was further stirred at 25 ° C. for 12 hours, and then the reaction product was filtered off by a centrifugal filter. Further, the reaction product was washed with methanol and then dried to obtain 15 g of a powdery polymer (poly (2-methoxyaniline-5-sulfonic acid)).

10 parts by mass of the obtained powdery polymer was dissolved in 100 parts by mass of water to obtain a polymer solution.
The column was filled with a cation exchange resin washed with ultrapure water (manufactured by Organo Corporation, "Amberlite IR-120B") so as to be 50 parts by mass with respect to 100 parts by mass of the polymer solution.
A polymer solution was passed through this column for cation exchange treatment to purify poly (2-methoxyaniline-5-sulfonic acid). Purified poly (2-methoxyaniline-5-sulfonic acid) is in the state of an aqueous solution dissolved in water, and poly (2-methoxyaniline-) with respect to the total mass of the poly (2-methoxyaniline-5-sulfonic acid) aqueous solution. The content of 5-sulfonic acid) is 9.1% by mass.

<Manufacturing of cleaning agent>
Dilute with water until the content of poly (2-methoxyaniline-5-sulfonic acid) with respect to the total mass of the poly (2-methoxyaniline-5-sulfonic acid) aqueous solution becomes 2% by mass to obtain a detergent. rice field.
The content of sodium ions with respect to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
In addition, the obtained cleaning agent was evaluated for corrosion prevention, foaming prevention, and metal contamination prevention. These results are shown in Table 1.

"Comparative Example 1"
2 parts by mass of sulfamic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 0.2 parts by mass of sodium polystyrene sulfonate (manufactured by Tosoh Organic Chemical Industries, Ltd., "Polynas PS-5") as an anionic surfactant, and 97. 8 parts by mass was mixed to obtain a cleaning agent.
The content of sodium ions with respect to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
In addition, the obtained cleaning agent was evaluated for corrosion prevention, foaming prevention, and metal contamination prevention. These results are shown in Table 1.

"Comparative Example 2"
2 parts by mass of sodium 4-aminobenzenesulfonate and 98 parts by mass of water were mixed to obtain a detergent.
The content of sodium ions with respect to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
In addition, the obtained cleaning agent was evaluated for corrosion prevention, foaming prevention, and metal contamination prevention. These results are shown in Table 1.

"Comparative Example 3"
A monomer dispersion was prepared by mixing 5 parts by mass of sodium 4-aminobenzenesulfonate and 95 parts by mass of water.
A cation exchange treatment was attempted on the obtained monomer dispersion liquid in the same manner as in Example 1, but precipitates were generated and the column was clogged, and the monomer dispersion liquid could not be recovered.

As is clear from Table 1, the cleaning agent obtained in Example 1 had a degree of erosion of less than 6.25 mm / year and was less corrosive to metals. Moreover, the cleaning agent obtained in Example 1 was difficult to foam. Further, the cleaning agent obtained in Example 1 had a sodium ion content of less than 1 mass ppm in ultrapure water in the evaluation of metal contamination prevention property, and was able to prevent metal contamination of the object to be cleaned.
As described above, the cleaning agent obtained in Example 1 is suitable as a cleaning agent for electronic materials because it has low corrosiveness to metals, is less likely to foam during cleaning, and can prevent metal contamination of the substrate.

On the other hand, the cleaning agent obtained in Comparative Example 1 was inferior in corrosion prevention property and foaming prevention property. In addition, the cleaning agent obtained in Comparative Example 1 had a high sodium ion content of 220 mass ppm and was inferior in metal contamination prevention property.
The cleaning agent obtained in Comparative Example 2 had low corrosiveness to metal and was difficult to foam, but had a high sodium ion content of 300 mass ppm and was inferior in metal contamination prevention property. Therefore, an attempt was made to purify the monomer sodium 4-aminobenzenesulfonate (Comparative Example 3), but the purification could not be performed because sodium 4-aminobenzenesulfonate was difficult to dissolve in water.

The cleaning agent of the present invention is useful as a cleaning agent for electronic materials such as FPD substrates and semiconductor device substrates.

Claims (7)

A cleaning agent containing water and an aniline-based polymer having a unit represented by the following general formula (1) and having an acidic group content of 80 mol% or more with respect to an aromatic ring.

In the formula (1), R ^{1 to} R ⁴ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, and acidic groups. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 1 to} R ⁴ is an acidic group. Here, the acidic group is a sulfonic acid group or a carboxy group. The cleaning agent according to claim 1, wherein the content of the alkali metal is 1 mass ppm or less. The cleaning agent according to claim 1 or 2, wherein the aniline-based polymer has a structure represented by the following general formula (3).

In the formula (3), R ^{12 to} R ²⁷ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, or an acidic group. , A hydroxy group, a nitro group, and a halogen atom, and ^{at least one of R 12 to} R ²⁷ is an acidic group. Further, n indicates the degree of polymerization. The detergent according to claim 3, wherein the aniline-based polymer is at least one of poly (2-sulfo-5-methoxy-1,4-iminophenylene) and poly (2-methoxyaniline-5-sulfonic acid). .. The cleaning agent according to any one of claims 1 to 4, which is for a flat panel display substrate or a semiconductor device substrate. A method for manufacturing a flat panel display substrate, wherein at least one of metal shavings and a resist film generated by etching is removed by the cleaning agent according to any one of claims 1 to 4 in the process for manufacturing a flat panel display substrate. .. A semiconductor device substrate in which at least one of a metal polishing residue and an abrasive generated by chemical mechanical polishing is removed by the cleaning agent according to any one of claims 1 to 4 in the process of manufacturing the semiconductor device substrate. Production method.