JP2018199767A - Detergent - Google Patents

Abstract

To provide a detergent that has low metal corrosiveness, is less likely to foam during cleaning, prevents metal contamination of a substrate, and has no restrictions in pH at the time of use.SOLUTION: A detergent contains an aniline polymer having an acidic group, and water, and is suitable as a detergent for a flat panel display substrate or semiconductor device substrate.SELECTED DRAWING: None

Description

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

  In a flat panel display (FPD) manufacturing process, a metal film and a resist film are sequentially formed on a substrate such as glass, and then the resist film is exposed, developed, and patterned to form a resist pattern. Things have been done. After the resist pattern is formed, a portion on which the resist is not formed is selectively etched, and the metal scrap and resist film generated by the etching are removed to obtain a substrate on which the resist pattern is formed.

A semiconductor device has a flattened surface by forming a metal film or the like on a substrate such as a silicon wafer and then performing a surface flattening process by chemical mechanical polishing (CMP) using an abrasive. Manufactured by stacking new layers on top.
Since the abrasive used in the CMP process and metal polishing residue are likely 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 an FPD substrate or a semiconductor device substrate.
However, the cleaning agent containing an anionic surfactant sometimes corrodes the metal film formed on the substrate. There is also a problem that bubbles are easily formed during cleaning, and the bubbles remain on the substrate.

Therefore, as a detergent that does not easily foam, for example, Patent Document 1 discloses sulfamic acid, an anionic surfactant having a sulfonic acid group in the molecule and a mass average molecular weight of 1,000 to 2,000,000, a chelating agent, and water. A cleaning agent containing and having a pH of 3 or less is disclosed.
In addition, as a detergent that does not contain a surfactant, for example, Patent Document 2 discloses a detergent that contains aminobenzenesulfonic acid, a water-miscible organic solvent, and water and has a pH of 6 to 11. ing.

JP 2010-163609 A JP 2009-224782 A

However, the cleaning agent described in Patent Document 1 uses a high molecular weight anionic surfactant and thus is relatively difficult to foam, but does not necessarily satisfy the foaming prevention property and is inferior in corrosion prevention. Moreover, there was a restriction of pH during 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 has a restriction of pH during use.

Moreover, the sulfamic acid contained in the cleaning agent described in Patent Document 1 and the aminobenzenesulfonic acid contained in the cleaning agent described in Patent Document 2 are likely to be mixed with alkali metals such as sodium at the time of production. As a result, sulfamic acid and aminobenzenesulfonic acid are blended into the cleaning agent in a state containing an 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, alkali metal mixed in sulfamic acid or aminobenzenesulfonic acid may be removed. However, in particular, aminobenzenesulfonic acid is difficult to dissolve in water, so it is difficult to purify 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 an object of the present invention is to provide a cleaning agent that has low corrosiveness to metals, is difficult to foam during cleaning, can prevent metal contamination of the substrate, and has no pH restriction during use. And

The present invention has the following aspects.
[1] A cleaning agent comprising an aniline polymer having an acidic group and water.
[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 polymer has a unit represented by the following general formula (1).

In formula (1), R ^{1 to} R ⁴ each independently represent 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 ^{1 to} R ⁴ is an acidic group. Here, the acidic group is a sulfonic acid group or a carboxy group.

[4] The cleaning agent according to any one of [1] to [3], which is for a flat panel display substrate or a semiconductor device substrate.

  According to the cleaning agent of the present invention, the corrosiveness to metal is low, it is difficult to foam during cleaning, metal contamination to the substrate can be prevented, and there is no restriction of pH during use.

Hereinafter, the present invention will be described in detail.
In the present invention, “cleaning” includes not only removing an object to be cleaned (for example, metal shaving residue, polishing residue, abrasive), but also removing (stripping) a resist film, for example.
In the present invention, “water-soluble” and “solubility” mean that 0.1 g or more is uniformly dissolved in 10 g of water or a mixed solvent of water and a water-soluble organic solvent (liquid temperature: 25 ° C.). To do.

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

<Aniline polymer>
An aniline-based polymer has an acidic group. The aniline polymer is water-soluble and has excellent solubility in water.
Here, the “acidic group” is a sulfonic acid group (—SO ₃ H) or a carboxy group (—COOH).
The sulfonic acid group includes a substituent having a sulfonic acid group (—R ⁵ SO ₃ H), an alkali metal salt, an ammonium salt, or a substituted ammonium salt of the sulfonic acid group.
On the other hand, the carboxy group includes a substituent having a carboxy group (—R ⁵ COOH), an alkali metal salt, an ammonium salt or a substituted ammonium salt of the carboxy group.
R ⁵ represents a linear or branched alkylene group having 1 to 24 carbon atoms, an arylene group or an aralkylene group.

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

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

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 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, an acidic group, A hydroxy group, a nitro group, a 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 aralkyl 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, a polymer having a unit represented by the following general formula (1) is preferable from the viewpoint of superior solubility in water among the polymers having the unit represented by the general formula (2).

In formula (1), R ^{1 to} R ⁴ each independently represent 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 ^{1 to} R ⁴ is an acidic group.
As the acidic group, a sulfonic acid group is preferable.

As the unit represented by the general formula (1), one of R ^{1 to} R ⁴ is a linear or branched alkoxy group having 1 to 4 carbon atoms in terms of easy production, Any one of these is a sulfonic acid group, and the remainder is a hydrogen atom.

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

  The aniline-based polymer preferably has an acidic group content of 70% or more, more preferably 80% or more, particularly 90% or more, from the viewpoint of improving solubility. preferable.

  Furthermore, the aniline-based polymer is a structural unit other than the unit represented by the general formula (1) as long as it does not affect the solubility or the like, and is substituted or unsubstituted aniline, thiophene, pyrrole, phenylene, vinylene, diene. One or more units selected from the group consisting of a valent unsaturated group and a divalent saturated group may be included.

  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 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. N represents the degree of polymerization.

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

The mass average molecular weight of the aniline-based polymer is preferably 3000 to 1000000, more preferably 5000 to 80000, and particularly preferably 10,000 to 70000.
Here, the mass average molecular weight of the aniline polymer is a mass average molecular weight (in terms of sodium polystyrene sulfonate) measured by gel permeation chromatography (GPC).

(Method for producing 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 acidic group-substituted anilines, alkali metal salts, ammonium salts and substituted ammonium salts thereof is polymerized using an oxidizing agent in the presence of a basic reaction aid. Can be obtained.

Examples of the acidic group-substituted aniline include sulfonic acid group-substituted anilines having a sulfonic acid group as an acidic group.
Typical examples of the sulfone group-substituted aniline are aminobenzene sulfonic acids, specifically 2-aminobenzene sulfonic acid, 3-aminobenzene sulfonic acid, 4-aminobenzene sulfonic acid, aniline-2,6-disulfone. Acid, 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 sulfone group-substituted anilines other than aminobenzenesulfonic acids include methylaminobenzenesulfonic acid, ethylaminobenzenesulfonic acid, n-propylaminobenzenesulfonic acid, iso-propylaminobenzenesulfonic acid, n-butylaminobenzenesulfonic acid, alkyl group-substituted aminobenzenesulfonic acids such as sec-butylaminobenzenesulfonic acid and t-butylaminobenzenesulfonic acid; methoxyaminobenzenesulfonic acid (for example, 2-methoxyaniline-5-sulfonic acid, 2-methoxyaniline-3-sulfone) Acid, 3-methoxyaniline-2-sulfonic acid, 3-methoxyaniline-5-sulfonic acid, etc.), alkoxy group-substituted aminobenzes such as ethoxyaminobenzenesulfonic acid, propoxyaminobenzenesulfonic acid, etc. Hydroxy group-substituted aminobenzenesulfonic acids; Nitro group-substituted aminobenzenesulfonic acids; Halogen-substituted aminobenzenesulfonic acids such as fluoroaminobenzenesulfonic acid, chloroaminobenzenesulfonic acid, bromoaminobenzenesulfonic acid, etc. .
Among these, an alkyl group-substituted aminobenzene sulfonic acid, an alkoxy group-substituted aminobenzene sulfonic acid, a hydroxy group-substituted aminobenzene sulfonic acid, or a halogen-substituted aminobenzene sulfone is obtained in that an aniline polymer having particularly excellent solubility is obtained. Acids are preferred, and alkoxy group-substituted aminobenzenesulfonic acids, alkali metal salts, ammonium salts and substituted ammonium salts thereof are particularly preferred in terms of easy production.
Each of these sulfonic acid group-substituted anilines may be used alone or in a mixture of two or more at any ratio.

Examples of the basic reaction aid used in the production of the aniline polymer include inorganic bases, ammonia, fatty amines, cyclic saturated amines, cyclic unsaturated amines, and the like.
As the basic reaction aid, an inorganic base is preferable, and specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.
In addition to inorganic bases, fatty amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, diethylmethylamine; pyridine, α-picoline, β-picoline, 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 in the production of the aniline polymer is not limited as long as the standard electrode potential is 0.6 V or more. For example, peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, peroxodisulfuric acid It is preferable to use peroxodisulfuric acid such as potassium; hydrogen peroxide or the like.
Each of these oxidizing agents may be used alone, or two or more kinds thereof may be mixed and used in an arbitrary ratio.

  Examples of the polymerization method include, for example, a method of dropping a mixed solution of a monomer and a basic reaction aid in an oxidant solution, a method of dropping an oxidant solution in a mixed solution of a monomer and a basic reaction aid, a reaction vessel, and the like. And a method in which a mixed solution of a monomer and a basic reaction aid and an oxidizing agent solution are added dropwise at the same time.

  After polymerization, the solvent is usually filtered off with a centrifuge. Furthermore, the filtrate is washed with a washing liquid as necessary, and then dried to obtain a polymer (aniline polymer).

  Monomers such as acidic group-substituted aniline, which are raw materials for aniline polymers, are likely to be mixed with alkali metals such as sodium during production. This is presumably because the alkali metal is incorporated into the monomer as the counter ion of the acidic group. Therefore, the aniline polymer obtained by polymerizing the monomer mixed with the alkali metal also contains the alkali metal. This alkali metal may be released into the cleaning liquid and adhere to the substrate during the cleaning of the FPD substrate, the semiconductor device substrate, and the like, causing metal contamination of the substrate.

However, since the aniline polymer used in the present invention is excellent in solubility in water or a water-soluble organic solvent, it can be easily purified.
In the purified aniline polymer, the alkali metal is sufficiently removed, so that it is possible to prevent metal contamination on the substrate when used as a cleaning agent.

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

Examples of the ion exchange method include column-type and batch-type treatment using a cation exchange resin; 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 then the polymer solution is brought into contact with a cation exchange resin or the like. It is preferable.
As a density | concentration of the aniline type polymer in a polymer solution, 0.1-20 mass% is preferable from a viewpoint of industrial property or refinement | purification efficiency, and 0.1-10 mass% is more preferable.

  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; ketones such as acetone, methyl ethyl ketone, ethyl isobutyl ketone and methyl isobutyl ketone 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 Amides such as dimethylformamide and dimethylacetamide; pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone; milk Methyl, ethyl lactate, beta-methoxyisobutyrate methyl butyrate, hydroxypropyl esters such as α- hydroxy methyl isobutyrate and the like.

Commercially available products can be used as the cation exchange resin, and strong acid type cation exchange resins such as “Amberlite” manufactured by Organo Corporation are preferred.
The form of the cation exchange resin is not particularly limited, and various forms can be used. Examples thereof include spherical fine particles, membranes, and fibers.
The amount of the cation exchange resin relative to the aniline 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 polymer. When the amount of the cation exchange resin is less than 100 parts by mass, the alkali metal is not easily removed. On the other hand, when the amount of the cation exchange resin exceeds 2000 parts by mass, the amount becomes excessive with respect to the polymer solution. Therefore, it is difficult to recover the polymer solution after the cation exchange resin is brought into contact with the cation exchange resin. Become.

Examples of the method for contacting the polymer solution and 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 contact the cation exchange resin.
Also, a method of performing cation exchange treatment by filling a column with a cation exchange resin and passing the polymer solution at a flow rate of preferably SV = 0.01 to 20, more preferably SV = 0.2 to 10. But you can.
Here, space velocity SV (1 / hr) = flow rate (m ³ / hr) / filter medium amount (volume: m ³ ).

The time for bringing the polymer solution into contact with the cation exchange resin is preferably 0.1 hours or more, and more preferably 0.5 hours or more, from the viewpoint of purification efficiency.
The upper limit value of the contact time is not particularly limited, and may be set as appropriate in accordance with conditions such as the concentration of the polymer solution, the amount of cation exchange resin, and a contact temperature described later.
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, from an industrial viewpoint.

  In the case of the electrodialysis method, the ion exchange membrane of the electrodialysis method is not particularly limited, but in order to further suppress permeation due to diffusion of impurities, an ion exchange membrane that has been subjected to a treatment that selectively permeates monovalent ions. In addition, it is preferable to use one having a molecular weight cut-off of 300 or less. As such an ion exchange membrane, for example, “Neocepta CMK (cation exchange membrane, fractional molecular weight 300)”, “Neoceptor AMX (anion exchange membrane, fractional molecular weight 300)” manufactured by Astom Co., Ltd. and the like are suitable. In addition, as an 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 bonded together 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 less than the limit current density. The applied voltage in the bipolar film is preferably 10 to 50V, and more preferably 25 to 35V.

The alkali metal is sufficiently removed from the aniline-based polymer thus purified.
The purified aniline-based polymer is in a state dissolved in an aqueous medium such as water. Therefore, if the aqueous medium is removed with an evaporator or the like, a solid aniline polymer can be obtained. However, the aniline polymer may be used as a cleaning agent in a state dissolved in the aqueous medium.

The content of the aniline polymer in the cleaning agent is calculated in terms of pure content (converted to solid content), preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and more preferably 1% by mass with respect to the total mass of the cleaning agent % Or more is more preferable. If the content of the aniline 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 polymer in the cleaning agent is calculated in terms of pure content (solid content conversion), preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less, based on the total mass of the cleaning agent. preferable.

<Water>
Examples of water include tap water, ion exchange water, pure water, and distilled water.
When purifying an aniline polymer using water as an aqueous medium and using the purified aniline polymer as it is dissolved in water, the content of the aniline polymer in the cleaning agent is within the above range. Alternatively, it may be concentrated or diluted by adding 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, and still more preferably 90 to 99% by mass with respect to the total mass of the cleaning agent.
In addition, the sum total of content of the aniline polymer and water contained in a cleaning agent shall not exceed 100 mass% with respect to the total mass of a cleaning agent.

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

The organic solvent is preferably a water-soluble organic solvent that is soluble in water. Examples of the water-soluble organic solvent include the water-soluble organic solvents exemplified above as the aqueous medium in the description of the purification of the aniline-based polymer.
1-99 mass% is preferable with respect to the total mass of a cleaning agent, as for content of the organic solvent in a cleaning agent, 3-95 mass% is more preferable, and 5-90 mass% is further more preferable.

Examples of the additive include known additives contained in cleaning agents used for cleaning FPD substrates, semiconductor device substrates, and the like. Specifically, antioxidants, rust inhibitors, pH adjusters, buffers, Examples include foaming agents, preservatives, and hydrotropes.
Note that it is preferable that the cleaning agent does not substantially contain a surfactant such as an anionic surfactant in consideration of prevention of corrosion of the metal film and prevention of foaming at the time of cleaning the FPD substrate and the semiconductor device substrate. Here, “substantially free” means 0.1 mass% or less with respect to the total mass of the cleaning agent.

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

<Manufacturing method of cleaning agent>
The cleaning agent of the present invention can be produced by mixing the above-mentioned aniline polymer, water, and optional components as necessary.
Further, as described above, since the purified aniline polymer is in a state dissolved in an aqueous medium, the purified aniline polymer dissolved in an aqueous medium may be used as a cleaning agent as it is, or as necessary. It is also possible to concentrate it, dilute it with water, or add optional ingredients to make it a cleaning agent.

The cleaning agent thus obtained has a sufficiently reduced alkali metal content. The content of the alkali metal in the cleaning agent is preferably 1 ppm by mass or less, more preferably 0.95 ppm by mass or less, and further preferably 0.9 ppm by mass or less with respect to the total mass of the cleaning agent. The smaller the alkali metal content in the cleaning agent, the better, and the lower limit is preferably 0 mass ppm.
Here, the content of the alkali metal in the cleaning agent is determined by performing 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 polymer having an acidic group and water.
An alkali metal such as sodium is likely to be mixed in the monomer as a raw material of the aniline polymer having an acidic group during the production. Monomers are difficult to purify because they are hardly soluble in water, and alkali metals are difficult to remove. This alkali metal may be released into the cleaning liquid and adhere to the substrate during cleaning of an FPD substrate, a semiconductor device substrate, or the like, which causes metal contamination of the substrate.

  However, the aniline-based polymer having an acidic group contained in the cleaning agent of the present invention is water-soluble and excellent in 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 is hard to foam and has low corrosiveness to metals.

Further, as described above, the conventional cleaning agent has a restriction on pH during use. For example, it is considered that the cleaning agent described in Patent Document 2 needs to be adjusted to pH 6 to 11 in order to dissolve aminobenzenesulfonic acid as a monomer in water.
However, since the aniline-based polymer having an acidic group contained in the cleaning agent 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 in an acidic state as well as alkaline, and there is no restriction on pH during use.

<Application>
The cleaning agent of the present invention can be used as a cleaning agent for cleaning electronic materials.
Examples of electronic materials to be cleaned (objects 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 an electronic component. 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 scraps and resist films generated by etching in the FPD manufacturing process. Is preferred.
When the cleaning agent of the present invention is used for a semiconductor device substrate, it should be applied as a cleaning agent used in a cleaning process for the purpose of removing metal debris and abrasives generated by CMP in a semiconductor device manufacturing process. Is preferred.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, a following example does not limit the scope of the present invention.
The various measurement / evaluation methods in Examples and Comparative Examples are as follows.

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

(Evaluation of corrosion prevention)
As a test piece, an aluminum substrate (ISO 7075-T6 equivalent product) that was previously degreased and surface-polished was used. The mass and material density of the specimen were measured.
After immersing the test piece in 100 parts by mass of the cleaning agent and holding it at 55 ° C. ± 1 ° C. for 7 days, the test piece was taken out from the cleaning agent. After removing the cleaning agent adhering to the test piece and drying the test piece, the mass of the test piece was measured. This was 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 ) × 10 × 365)} / (d × S × T) (I)
(In formula (I), “X” is the erosion degree [mm / year] of the test piece, “W ₁ ” is the mass [g] of the test piece before dipping 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 being immersed in the cleaning agent, and “S” is the immersion area [cm] of the test piece. ² ], and “T” is the number of immersion days (retention days).)

The corrosion resistance against metals was evaluated according to the following evaluation criteria.
○: Erosion degree is less than 6.25 mm / year.
X: Erosion degree 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, vigorously shaken for 30 seconds, and then left for 1 minute. The state of the foam after standing was visually observed, and the antifoaming property was evaluated according to the following evaluation criteria.
○: No bubbles can be confirmed.
X: A bubble is confirmed.

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

"Example 1"
<Production of aniline-based polymer having acidic group>
100 mmol of 2-methoxyaniline-5-sulfonic acid was dissolved in 300 mL of a 4 mol / L triethylamine solution (solvent: water / acetonitrile = 5/5) 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 oxidant solution.
Subsequently, the oxidizing agent solution was dropped into the monomer solution. After completion of the dropwise addition, the mixture was further stirred at 25 ° C. for 12 hours, and then the reaction product was separated by a centrifugal filter. Further, the reaction product was washed with methanol and 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.
A cation exchange resin (manufactured by Organo Corporation, “Amberlite IR-120B”) washed with ultrapure water was packed in a column so as to be 50 parts by mass with respect to 100 parts by mass of the polymer solution.
The polymer solution was passed through this column for cation exchange treatment to purify poly (2-methoxyaniline-5-sulfonic acid). The purified poly (2-methoxyaniline-5-sulfonic acid) is in the form of an aqueous solution dissolved in water, and the poly (2-methoxyaniline-5-sulfonic acid) is added to the total mass of the aqueous poly (2-methoxyaniline-5-sulfonic acid) solution. The content of (5-sulfonic acid) is 9.1% by mass.

<Manufacture of cleaning agent>
Diluting by adding water until the content of poly (2-methoxyaniline-5-sulfonic acid) is 2% by mass relative to the total mass of the aqueous solution of poly (2-methoxyaniline-5-sulfonic acid) to obtain a cleaning agent It was.
The content of sodium ions relative to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
Moreover, about the obtained cleaning agent, corrosion prevention property, foaming prevention property, and metal contamination prevention property were evaluated. 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 part by mass of sodium polystyrene sulfonate (manufactured by Tosoh Organic Chemical Co., 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 relative to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
Moreover, about the obtained cleaning agent, corrosion prevention property, foaming prevention property, and metal contamination prevention property were evaluated. 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 cleaning agent.
The content of sodium ions relative to the total mass of the obtained cleaning agent was measured. The results are shown in Table 1.
Moreover, about the obtained cleaning agent, corrosion prevention property, foaming prevention property, and metal contamination prevention property were evaluated. 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.
The obtained monomer dispersion was subjected to a cation exchange treatment in the same manner as in Example 1. However, precipitates were generated, the column was clogged, and the monomer dispersion 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 low corrosiveness to metals. Moreover, the cleaning agent obtained in Example 1 was difficult to foam. Furthermore, 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 properties, and was able to prevent metal contamination on 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, hardly foams 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 and foaming prevention. In addition, the detergent obtained in Comparative Example 1 had a high sodium ion content of 220 ppm by mass and was inferior in metal contamination prevention.
The cleaning agent obtained in Comparative Example 2 had low corrosiveness to metals and was difficult to foam, but had a high sodium ion content of 300 ppm by mass and was inferior in metal contamination prevention. Therefore, an attempt was made to purify sodium 4-aminobenzenesulfonate, which is a monomer (Comparative Example 3), but purification was not possible 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 (4)

  A cleaning agent comprising an aniline-based polymer having an acidic group and water.   The cleaning agent according to claim 1, wherein the alkali metal content is 1 mass ppm or less. The cleaning agent according to claim 1 or 2, wherein the aniline polymer has a unit represented by the following general formula (1).

In formula (1), R ^{1 to} R ⁴ each independently represent 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 ^{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 any one of claims 1 to 3, which is for a flat panel display substrate or a semiconductor device substrate.