JP7469474B2 - Semiconductor substrate cleaning solution - Google Patents

Description

The present invention relates to a cleaning liquid for semiconductor substrates.

Semiconductor elements such as CCDs (Charge-Coupled Devices) and memories are manufactured by forming fine electronic circuit patterns on a substrate using photolithography technology. Specifically, a resist film is formed on a laminate having a metal film, which serves as the wiring material, an etching stop layer, and an interlayer insulating layer on a substrate, and a photolithography process and a dry etching process (e.g., plasma etching process) are performed to manufacture the semiconductor elements.

In the manufacture of semiconductor devices, a chemical mechanical polishing (CMP) process may be performed to planarize a semiconductor substrate surface having a metal wiring film, a barrier metal, an insulating film, etc., using a polishing slurry containing abrasive particles (e.g., silica, alumina, etc.) In the CMP process, metal components derived from the abrasive particles used in the CMP process, the polished wiring metal film, and/or the barrier metal, etc., tend to remain on the semiconductor substrate surface after the CMP process.
Since these residues can cause short circuits between wirings and affect the electrical characteristics of the semiconductor, a cleaning process is generally carried out to remove these residues from the surface of the semiconductor substrate.

For example, Patent Document 1 describes a cleaning agent for electronic materials that contains "a compound (A) having a carboxyl group and/or a carboxylate group and having a structure in which a hydroxyl group is bonded to the carbon at the α-position and the β-position of the carboxyl group and/or the carboxylate group, and water."

JP 2014-141669 A

The present inventors have studied the cleaning liquid for semiconductor substrates described in Patent Document 1 and the like and have found that it is difficult to achieve both excellent cleaning performance for semiconductor substrates having a metal film containing tungsten after CMP processing and excellent corrosion inhibition performance for tungsten when cleaning a metal film containing tungsten.

The present invention aims to provide a cleaning liquid for semiconductor substrates that exhibits excellent cleaning performance for semiconductor substrates having a metal film containing tungsten after CMP processing, and also has excellent corrosion inhibition performance for tungsten when cleaning a metal film containing tungsten.

The inventor has discovered that the above problem can be solved by the following configuration:

[1] A semiconductor substrate cleaning solution used for cleaning a semiconductor substrate, comprising:
The composition includes a polymer, an alkanolamine, a complexing agent having an acid group, and water,
The weight average molecular weight of the polymer is 2,000 to 900,000;
the content of the complexing agent is 2.5 mass % or more and less than 20.0 mass % based on the total mass of the cleaning solution for semiconductor substrates,
A cleaning solution for semiconductor substrates, the pH of which is less than 7.0.
[2] The cleaning solution for semiconductor substrates according to [1], wherein the complexing agent has at least one selected from the group consisting of a carboxyl group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group.
[3] The cleaning solution for semiconductor substrates according to [1] or [2], wherein the polymer has a weight average molecular weight of 2,000 to 500,000.
[4] The cleaning solution for semiconductor substrates according to any one of [1] to [3], wherein the alkanolamine has a pKa of 7.50 to 15.00.
[5] The cleaning solution for semiconductor substrates according to any one of [1] to [4], wherein the alkanolamine comprises at least one selected from the group consisting of monoethanolamine, isopropanolamine, and tris(hydroxymethyl)aminomethane.
[6] The cleaning solution for semiconductor substrates according to any one of [1] to [5], wherein the content of the alkanolamine is 0.01 to 7.0 mass % based on the total mass of the cleaning solution for semiconductor substrates.
[7] The cleaning solution for semiconductor substrates according to any one of [1] to [6], wherein a mass ratio of a content of the complexing agent to a content of the alkanolamine is 0.1 to 1000.0.
[8] The cleaning solution for semiconductor substrates according to any one of [1] to [7], wherein a mass ratio of a content of the complexing agent to a content of the polymer is 1.0 to 100.0.
[9] The cleaning solution for semiconductor substrates according to any one of [1] to [8], wherein the content of the complexing agent is 3.0 to 10.0 mass % based on the total mass of the cleaning solution for semiconductor substrates.
[10] The cleaning solution for semiconductor substrates according to any one of [1] to [9], wherein the content of the complexing agent is 3.0 to 4.0 mass % based on the total mass of the cleaning solution for semiconductor substrates.
[11] The cleaning solution for semiconductor substrates according to any one of [1] to [10], further comprising an anticorrosive.
[12] The cleaning solution for a semiconductor substrate according to any one of [1] to [11], further comprising a surfactant.
[13] The cleaning liquid for a semiconductor substrate according to [12], wherein the surfactant includes an anionic surfactant.
[14] The cleaning liquid for semiconductor substrates according to [12] or [13], wherein the surfactant comprises at least one selected from the group consisting of alkyl phosphate esters and polyoxyethylene alkyl phosphate esters.
[15] The cleaning solution for a semiconductor substrate according to any one of [1] to [14], further comprising a hydrophilic organic solvent.
[16] The cleaning solution for a semiconductor substrate according to any one of [1] to [15], wherein the semiconductor substrate has a metal film containing tungsten.
[17] The cleaning solution for a semiconductor substrate according to any one of [1] to [16], which is used as a cleaning solution to be applied to a semiconductor substrate that has been subjected to a chemical mechanical polishing process.

According to the present invention, a semiconductor substrate cleaning liquid can be provided that has excellent cleaning performance for semiconductor substrates having a metal film containing tungsten after CMP processing, and also has excellent corrosion inhibition performance for tungsten when cleaning a metal film containing tungsten.

An example of an embodiment of the present invention will be described below.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.

In this specification, when two or more types of a component are present, the "content" of the component means the total content of those two or more components.
In this specification, "ppm" means "parts-per-million (10 ^-6 )" and "ppb" means "parts-per-billion (10 ^-9 )."
In the present specification, unless otherwise specified, the compounds described may include isomers (compounds having the same number of atoms but different structures), optical isomers, and isotopes. In addition, the compounds may include only one type of isomer or isotope, or may include multiple types of isomers and isotopes.

In this specification, psi means pound-force per square inch, with 1 psi = 6,894.76 Pa.

In this specification, unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values calculated using polystyrene as a standard substance measured by a gel permeation chromatography (GPC) analyzer using TSKgel GMHxL, TSKgel G4000HxL, or TSKgel G2000HxL (all of which are product names manufactured by Tosoh Corporation) as a column, THF (tetrahydrofuran) as an eluent, a differential refractometer as a detector, and polystyrene as a standard substance.
In this specification, unless otherwise specified, the molecular weight of a compound having a molecular weight distribution is the weight average molecular weight.

[Cleaning solution for semiconductor substrates]
The cleaning solution for semiconductor substrates (hereinafter also referred to as "cleaning solution") of the present invention is a cleaning solution used for cleaning semiconductor substrates, and contains a predetermined polymer described below, an alkanolamine, a complexing agent having a predetermined amount of acid groups, and water, and has a pH of less than 7.0.

Although the mechanism by which the above-mentioned composition solves the problems of the present invention is not clear, it is presumed that the above-mentioned components act in a coordinated manner to obtain the desired effect.
It is presumed that the polymer, alkanolamine, and complexing agent having an acid group interact with the residue on the semiconductor substrate surface after CMP processing, thereby contributing to improved cleaning performance and improved corrosion inhibition performance.
Hereinafter, the effect of the present invention is also referred to as being superior in at least one of the cleaning performance of the cleaning solution for a semiconductor substrate having a metal film containing tungsten after CMP processing and the corrosion inhibition performance for tungsten when cleaning a metal film containing tungsten.

[pH]
The pH of the cleaning solution is less than 7.0.
Among these, in terms of obtaining superior effects of the present invention, the pH of the cleaning solution is preferably 0.1 to 6.9, more preferably 1.0 to 6.9, even more preferably 2.0 to 6.9, particularly preferably 2.5 to 6.0, and most preferably 5.0 to 6.5.
The pH of the cleaning solution can be measured using a known pH meter according to a method in accordance with JIS Z8802-1984. The pH is measured at a temperature of 25°C.

Below, we will explain each component contained in the cleaning solution.

[Polymer]
The cleaning solution includes a polymer.
The weight average molecular weight (Mw) of the polymer is 2,000 to 900,000, and from the viewpoint of obtaining superior effects of the present invention, it is preferably 2,000 to 800,000, more preferably 2,000 to 500,000, even more preferably 2,000 to 50,000, and particularly preferably 2,000 to 30,000.
The weight average molecular weight is a weight average molecular weight calculated as polyethylene glycol, measured by gel permeation chromatography (GPC).

The polymer is preferably a water-soluble polymer.
The term "water-soluble polymer" refers to a compound in which two or more structural units are linked in a linear or network shape via covalent bonds, and the mass of the polymer that dissolves in 100 g of water at 20°C is 0.1 g or more.
When the cleaning liquid contains a water-soluble polymer, the cleaning performance of the cleaning liquid is improved by interacting with a substrate having a metal film or with abrasive particles (eg, silica, alumina, etc.) contained in the polishing slurry.

Examples of the water-soluble polymer include polyacrylic acid, polymethacrylic acid, polymaleic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polystyrene sulfonic acid, and salts thereof; copolymers of monomers such as styrene, α-methylstyrene, and/or 4-methylstyrene with acid monomers such as (meth)acrylic acid and/or maleic acid, and salts thereof; copolymers of (meth)acrylic acid and maleic acid, and salts thereof; polymers having structural units having aromatic hydrocarbon groups obtained by condensing benzenesulfonic acid and/or naphthalenesulfonic acid with formalin, and salts thereof; vinyl-based synthetic polymers such as polyvinyl alcohol, polyoxyethylene, polyvinylpyrrolidone, polyvinylpyridine, polyacrylamide, polyvinylformamide, polyethyleneimine, polyvinyloxazoline, polyvinylimidazole, and polyallylamine; and modified products of natural polysaccharides such as hydroxyethyl cellulose, carboxymethyl cellulose, and processed starch.
Among these, the water-soluble polymer is preferably a polymer having an acid group (e.g., a carboxy group, a phosphoric acid group, or a sulfonic acid group), and more preferably polyacrylic acid, polymaleic acid, a copolymer of styrene and an acid monomer such as (meth)acrylic acid and/or maleic acid, a copolymer of (meth)acrylic acid and maleic acid, or a salt thereof.

The water-soluble polymer may be a homopolymer or a copolymer in which two or more types of monomers are copolymerized.
Examples of the monomer include a monomer selected from the group consisting of a monomer having a carboxy group, a monomer having a sulfonic acid group, a monomer having a hydroxyl group, a monomer having a polyethylene oxide chain, a monomer having an amino group, and a monomer having a heterocycle.
The water-soluble polymer is preferably a polymer consisting essentially of structural units derived from a monomer selected from the above group. The fact that the water-soluble polymer consists essentially of structural units derived from a monomer selected from the above group means, for example, that the content of structural units derived from a monomer selected from the above group is 95 to 100% by mass (preferably 99 to 100% by mass) based on the total mass of the polymer.

The polymer preferably has a structural unit having a carboxy group (such as a structural unit derived from (meth)acrylic acid).
The content of the structural unit having a carboxy group is preferably from 30 to 100% by mass, more preferably from 70 to 100% by mass, and even more preferably from 85 to 100% by mass, based on the total mass of the polymer.

Examples of the polymer include the water-soluble polymers described in paragraphs [0043] to [0047] of JP 2016-171294 A, the contents of which are incorporated herein by reference.

The polymers may be used alone or in combination of two or more.
The content of the polymer is preferably from 0.01 to 10% by mass, more preferably from 0.05 to 3% by mass, and even more preferably from 0.5 to 2% by mass, based on the total mass of the cleaning liquid.
When the content of the polymer is within the above range, the polymer is appropriately adsorbed onto the surface of the substrate, contributing to an improvement in the corrosion inhibition performance of the cleaning liquid, and also achieving a good balance in the viscosity and/or cleaning performance of the cleaning liquid.
The content of the polymer is preferably from 1.0 to 45.0% by mass, more preferably from 10.0 to 45.0% by mass, and even more preferably from 10.0 to 40.0% by mass, based on the total mass of the cleaning liquid excluding the solvent.

[Alkanolamine]
The cleaning solution comprises an alkanolamine.
Alkanolamines are compounds having at least one of a primary amino group to a tertiary amino group, and further having at least one hydroxyl group (preferably a hydroxyalkyl group) in the molecule.
The alkanolamine does not include the quaternary ammonium compounds described below.

The alkanolamine preferably has 1 to 5 hydroxyl groups, more preferably 1 to 3 hydroxyl groups, and even more preferably 1 or 2 hydroxyl groups.
The total number of primary amino groups to tertiary amino groups contained in the alkanolamine is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.
Moreover, the alkanolamine preferably has any one of a primary amino group to a tertiary amino group, more preferably has any one of a primary amino group and a secondary amino group, and further preferably has a primary amino group.

As the alkanolamine, a compound represented by formula (A) is preferred.

In formula (A), R ^a1 and R ^a2 each independently represent a hydrogen atom or an alkyl group which may have a hydroxyl group.
The alkyl group may be linear or branched.
The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.
The number of hydroxyl groups contained in the alkyl group is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.

L ^a1 represents an alkylene group which may have a hydroxyl group.
The alkylene group may be linear or branched.
The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, further preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms.
The alkylene group preferably has 1 to 5 hydroxyl groups, more preferably 1 to 3 hydroxyl groups, and further preferably 0.

Examples of alkanolamines include monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), tris(hydroxymethyl)aminomethane, N-methylethanolamine, N-methyl-N,N-diethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-(β-aminoethyl)ethanolamine, N-ethylethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, 2-(dimethylamino)-2-methyl-1-propanol, and dimethylmonoethanolamine.
Among these, the alkanolamine preferably includes at least one selected from the group consisting of isopropanolamine, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), tris(hydroxymethyl)aminomethane, N-ethylethanolamine, monopropanolamine, triisopropanolamine, N-methylethanolamine, 2-amino-2-methyl-1-propanol, and 2-(dimethylamino)-2-methyl-1-propanol, more preferably includes at least one selected from the group consisting of monoethanolamine, isopropanolamine, and trishydroxymethylaminomethane, and even more preferably includes isopropanolamine.

The pKa (acid dissociation constant) of the alkanolamine is preferably from 5.00 to 20.00, more preferably from 7.50 to 15.00, and even more preferably from 9.00 to 14.50, in view of excellent stability over time of the cleaning solution.
When two or more alkanolamines are contained, it is preferable that at least one of the alkanolamines satisfies the pKa range, it is more preferable that the alkanolamine contained at the greatest content satisfies the pKa range, and it is even more preferable that the alkanolamines contained in an amount of 50 mass% or more, based on the total mass of the alkanolamines, satisfy the pKa range.
The pKa is a value determined using the SC-Database (http://acadsoft.co.uk/scdbase/SCDB_software/scdb_download.htm).

The ClogP value of the alkanolamine is preferably from -5.00 to 1.00, more preferably from -2.00 to 1.00, and even more preferably from -1.00 to 1.00.
In this specification, the ClogP value is a value obtained by calculating the common logarithm logP of the partition coefficient P between 1-octanol and water. The method and software used for calculating the ClogP value may be publicly known. In this specification, unless otherwise specified, the Clog value is a value obtained using the ClogP program incorporated in ChemBioDrawUltra 12.0 by Cambridgesoft.

The alkanolamines may be used alone or in combination of two or more kinds.
The content of the alkanolamine is preferably 0.01 to 10.0 mass%, more preferably 0.01 to 7.0 mass%, still more preferably 0.01 to 5.0 mass%, particularly preferably 0.01 to 3.0 mass%, and most preferably 0.01 to 2.0 mass%, relative to the total mass of the cleaning solution, from the viewpoint of providing a well-balanced and excellent performance of the cleaning solution.
The content of the alkanolamine is preferably from 0.01 to 30.0 mass%, more preferably from 0.1 to 30.0 mass%, still more preferably from 1.0 to 30.0 mass%, and particularly preferably from 1.0 to 25.0 mass%, based on the total mass of the cleaning liquid excluding the solvent.

[Complexing Agent Having an Acid Group]
The cleaning solution contains a complexing agent having an acid group (hereinafter also referred to as a "specific complexing agent").
The specific complexing agent is a compound that has an acid group and bonds with a metal ion to form a complex ion. The specific complexing agent is a compound different from the components contained in the above-mentioned cleaning solution, the surfactant, the anticorrosive agent, the preservative, and the pH adjuster described below.
The content of the specific complexing agent is 2.5 mass% or more and less than 20.0 mass% based on the total mass of the cleaning solution. From the viewpoint of improving cleaning performance, the content is preferably 2.5 to 18.5 mass%, more preferably 2.5 to 15.0 mass%, even more preferably 2.5 to 10.0 mass%, particularly preferably 3.0 to 10.0 mass%, and most preferably 3.0 to 4.0 mass%.
The content of the specific complexing agent is preferably 45.0 to 98.0 mass%, more preferably 50.0 to 95.0 mass%, still more preferably 50.0 to 90.0 mass%, particularly preferably 50.0 to 85.0 mass%, and most preferably 50.0 to 70.0 mass%, based on the total mass of the cleaning solution excluding the solvent.

Examples of the acid group contained in the specific complexing agent include a carboxy group, a phosphoric acid group, a sulfonic acid group, a phosphonic acid group, a sulfinic acid group, and a sulfenic acid group.
In particular, the specific complexing agent preferably has at least one selected from the group consisting of a carboxy group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group, more preferably has at least one selected from the group consisting of a carboxy group, a phosphonic acid group, and a sulfonic acid group, and even more preferably has a carboxy group.
The specific complexing agent also preferably has any one of a carboxy group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group.
The specific complexing agent preferably has 1 to 10 acid groups, more preferably 1 to 7 acid groups, further preferably 1 to 6 acid groups, and particularly preferably 1 to 4 acid groups.

<Complexing Agent Having a Carboxy Group>
The complexing agent having a carboxy group is a complexing agent having at least one carboxy group in the molecule.
Examples of the specific complexing agent having a carboxy group include aminopolycarboxylic acids, amino acids, aliphatic carboxylic acids, and aromatic carboxylic acids.
Among these, the specific complexing agent having a carboxy group is preferably an aminopolycarboxylic acid or an amino acid, and more preferably an aminopolycarboxylic acid.
When the specific complexing agent contains an amino acid, the amino acid has a coordination portion and a hydrophilic portion within the molecule, and therefore is easily coordinated to a substrate having a metal film or to abrasive particles (e.g., silica, alumina, etc.) contained in the polishing slurry, or, when the amino acid coordinates to the abrasive particles, the surface of the abrasive particles becomes hydrophilic, allowing the abrasive particles to be efficiently removed.
The specific complexing agent preferably has 1 to 10 carboxy groups, more preferably 1 to 5 carboxy groups, and even more preferably 1 to 4 carboxy groups.

As the aminopolycarboxylic acid, a compound represented by formula (B1) is preferred.

_n1 represents an integer from 1 to 10.
Among them, _n1 is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably an integer of 2 to 3.

Examples of aminopolycarboxylic acids include nitrilotriacetic acid, butylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetrapropionic acid, triethylenetetraminehexaacetic acid, 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid, propylenediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexanetetraacetic acid, ethylenediaminediacetic acid, ethylenediaminedipropionic acid, 1,6-hexamethylene-diamine-N,N,N',N'-tetraacetic acid, N,N-bis(2-hydroxybenzyl)ethylenediamine-N,N-diacetic acid, diaminopropanetetraacetic acid, 1,4,7,10-tetraazacyclododecane-tetraacetic acid, diaminopropanoltetraacetic acid, (hydroxyethyl)ethylenediaminetriacetic acid, and iminodiacetic acid (IDA).
Of these, the aminopolycarboxylic acid is preferably DTPA or EDTA.

As the amino acid, a compound represented by formula (B2) is preferred, and a compound represented by formula (B3) is more preferred.

In formula (B2), R ^b1 represents a hydrogen atom or a hydrocarbon group which may have a hetero atom.
The hydrocarbon group may be linear, branched, or cyclic (which may be monocyclic or polycyclic).
The hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms.
Examples of the hydrocarbon group include an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The hydrocarbon group is preferably an alkyl group, an alkenyl group, an alkylene group, or an aryl group, which may have a heteroatom, and more preferably an alkyl group which may have a heteroatom.

R ^b2 and R ^b3 each independently represent a hydrogen atom or a hydroxyalkyl group.
The hydroxylalkyl group (an alkyl group having a hydroxyl group) preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.
Examples of the hydroxylalkyl group include a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, and a hydroxyhexyl group. Of these, a hydroxyethyl group is preferred.

R ^b4 represents a hydrogen atom, a hydroxyl group, a carboxy group, or -SR ^b7 .
R ^b7 represents a hydrogen atom or an alkyl group.
The alkyl group may be linear, branched, or cyclic.
The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms, and is particularly preferably a methyl group.

L ^b1 represents a single bond or an alkylene group.
The alkylene group may be linear, branched, or cyclic.
The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.

R ^b5 and R ^b6 have the same meanings and preferred ranges as R ^b2 and R ^b3 in formula (B2) above.

Examples of amino acids include alanine (2-aminopropionic acid or 3-aminopropionic acid), arginine, asparagine, aspartic acid, cystine, cysteine, glutamine, glutamic acid, glycine or a derivative thereof, isoleucine, leucine, lysine, methionine, phenylalanine, serine, ethionine, threonine, tyrosine, valine, tryptophan, histidine or a derivative thereof, 2-amino-3-aminopropanoic acid, and proline.
Examples of the amino acid include the compounds described in paragraphs [0021] to [0023] of JP2016-086094A.
An example of the glycine derivative is N,N-di(2-hydroxyethyl)glycine.
As the histidine derivative, the compounds described in JP-A-2015-165561 and JP-A-2015-165562 can be used, the contents of which are incorporated herein by reference.
Among these, the amino acid preferably includes at least one selected from the group consisting of serine, alanine, glycine or a derivative thereof, methionine, histidine or a derivative thereof, arginine, glutamine, asparagine, aspartic acid, glutamic acid, and cysteine, more preferably includes at least one selected from the group consisting of serine, alanine, glycine or a derivative thereof, methionine, aspartic acid, glutamic acid, and cysteine, further preferably includes a glycine derivative, and particularly preferably includes N,N-bis(2-hydroxyethyl)glycine (DHEG).

An aliphatic carboxylic acid is a compound having a carboxy group and an aliphatic group in the molecule.
In addition, the aliphatic carboxylic acid preferably further has a hydroxyl group.

As the aliphatic carboxylic acid, a compound represented by formula (B4) is preferred.

In formula (B4), L ^b2 represents a single bond or a divalent linking group.
Examples of the divalent linking group represented by L ^b2 include an ether group, a carbonyl group, an ester group, a thioether group, -SO ₂ -, -NT- (T is, for example, a hydrogen atom or a substituent such as an alkyl group), a divalent hydrocarbon group (for example, an alkylene group, an alkenylene group, an alkynylene group, and an arylene group), and combinations of these.
The divalent linking group may be linear, branched, or cyclic.
The divalent linking group represented by L ^b2 may further have a substituent. Examples of the substituent include an alkyl group, an aryl group, a hydroxyl group, a carboxy group, an amino group, and a halogen atom.
Of these, the divalent linking group is preferably a single bond or a divalent hydrocarbon group, and more preferably an alkylene group.
The divalent linking group preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms.

Aliphatic carboxylic acids include, for example, gluconic acid, glycolic acid, glyceric acid, citric acid, maleic acid, malic acid, tartaric acid, oxalic acid, malonic acid, and succinic acid.
Among them, the aliphatic carboxylic acid preferably contains at least one selected from the group consisting of citric acid, tartaric acid, and succinic acid.

An aromatic carboxylic acid is a compound having a carboxy group and an aromatic group in the molecule.
Aromatic carboxylic acids include, for example, phenyllactic acid, hydroxyphenyllactic acid, and phenylsuccinic acid.

<Complexing Agent Having a Phosphate Group>
The complexing agent having a phosphate group is a complexing agent having at least one phosphate group in the molecule.
The complexing agent having a phosphate group is a compound different from the complexing agents described above.
The specific complexing agent preferably has 1 to 10 phosphate groups, more preferably 2 to 8 phosphate groups, and even more preferably 4 to 7 phosphate groups.

Examples of complexing agents having a phosphate group include polyphosphoric acids, such as diphosphoric acid, metaphosphoric acid, and hexametaphosphoric acid, and phytic acid.
Among these, the complexing agent having a phosphate group is preferably diphosphoric acid, hexametaphosphoric acid, or phytic acid, and more preferably phytic acid.

<Complexing Agent Having Sulfonic Acid Group>
The complexing agent having a sulfonic acid group is a complexing agent having at least one sulfonic acid group in the molecule.
The complexing agent having a sulfonic acid group is a compound different from the complexing agents described above.
The specific complexing agent preferably has 1 to 10 sulfonic acid groups, more preferably 1 to 5 sulfonic acid groups, and even more preferably 1 to 3 sulfonic acid groups.

As a complexing agent having a sulfonic acid group, a compound represented by formula (C) is preferred.

R ^C —SO ₃ H Formula (C)
In formula (C), R 3 ^C represents an alkyl group or an aryl group which may have a substituent.
The alkyl group which may have a substituent and is represented by R 3 ^C may be linear, branched, or cyclic (which may be monocyclic or polycyclic).
The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.
The aryl group which may have a substituent and is represented by R 3 ^C may be a monocyclic, polycyclic or condensed ring.
The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, further preferably 6 to 15 carbon atoms, and particularly preferably 6 to 8 carbon atoms.
Examples of the substituents on the alkyl and aryl groups include alkyl groups, aryl groups, hydroxyl groups, carboxy groups, amino groups, and halogen atoms, with alkyl groups being preferred.

Examples of complexing agents having a sulfonic acid group include naphthalenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, benzenesulfonic acid, methanesulfonic acid, and ethanesulfonic acid.
Among these, the complexing agent having a sulfonic acid group is preferably p-toluenesulfonic acid, methanesulfonic acid, or ethanesulfonic acid.

<Complexing Agent Having a Phosphonic Acid Group>
The complexing agent having a phosphonic acid group is a complexing agent having at least one phosphonic acid group in the molecule.
The complexing agent having a phosphonic acid group is a compound different from the complexing agents described above.
The number of phosphonic acid groups contained in the specific complexing agent is preferably 1 or more, more preferably 2 or more, further preferably 2 to 10, particularly preferably 2 to 4, and most preferably 2 to 3.

Examples of complexing agents having a phosphonic acid group include a compound represented by formula (P1), a compound represented by formula (P2), and a compound represented by formula (P3).

In formula (P1), X represents a hydrogen atom or a hydroxyl group.
X is preferably a hydroxyl group.

R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.
The alkyl group having 1 to 10 carbon atoms represented by R ¹¹ may be linear, branched, or cyclic.
R ¹¹ is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.
In the specific examples of alkyl groups described in this specification, n- represents a normal form.

Preferred compounds represented by formula (P1) are ethylidene diphosphonic acid, 1-hydroxyethylidene-1,1'-diphosphonic acid (HEDPO), 1-hydroxypropylidene-1,1'-diphosphonic acid, and 1-hydroxybutylidene-1,1'-diphosphonic acid.

In formula (P2), Q represents a hydrogen atom or R ¹³ —PO ₃ H ₂ .
Q is preferably —R ¹³ —PO ₃ H ₂ .
R ¹² and R ¹³ each independently represent an alkylene group.
The alkylene group represented by R ¹² includes, for example, alkylene groups having 1 to 12 carbon atoms.
The alkylene group may be linear, branched, or cyclic, and is preferably linear or branched.
The alkylene group represented by R ¹² is preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and even more preferably an ethylene group.

The alkylene group represented by R ¹³ includes an alkylene group having 1 to 10 carbon atoms.
The alkylene group may be linear, branched, or cyclic, and is preferably linear or branched.
The alkylene group is preferably an alkylene group having 1 to 4 carbon atoms, more preferably a methylene group or an ethylene group, and even more preferably a methylene group.

Y represents a hydrogen atom, —R ¹³ —PO ₃ H ₂ , or a group represented by formula (P4).
Y is preferably —R ¹³ —PO ₃ H ₂ or a group represented by formula (P4), and more preferably a group represented by formula (P4).

In formula (P4), Q and R ¹³ have the same meanings as Q and R ¹³ in formula (P2).

Preferred compounds represented by formula (P2) are ethylaminobis(methylene phosphonic acid), dodecylaminobis(methylene phosphonic acid), nitrilotris(methylene phosphonic acid) (NTPO), ethylenediaminebis(methylene phosphonic acid) (EDDPO), 1,3-propylenediaminebis(methylene phosphonic acid), ethylenediaminetetra(methylene phosphonic acid) (EDTPO), ethylenediaminetetra(ethylene phosphonic acid), 1,3-propylenediaminetetra(methylene phosphonic acid) (PDTMP), 1,2-diaminopropanetetra(methylene phosphonic acid), or 1,6-hexamethylenediaminetetra(methylene phosphonic acid).

In formula (P3), R ¹⁴ and R ¹⁵ each independently represent an alkylene group having 1 to 4 carbon atoms.
The alkylene group having 1 to 4 carbon atoms represented by R ¹⁴ and R ¹⁵ may be linear or branched.
Examples of the alkylene group having 1 to 4 carbon atoms represented by R ¹⁴ and R ¹⁵ include a methylene group, an ethylene group, a propylene group, a trimethylene group, an ethylmethylene group, a tetramethylene group, a 2-methylpropylene group, a 2-methyltrimethylene group, and an ethylethylene group, and an ethylene group is preferable.

n represents an integer of 1 to 4.
Among these, n is preferably an integer of 1 to 2.

At least four of Z ¹ to Z ⁴ and n Z ^5s represent an alkyl group having a phosphonic acid group, and the remainder represent an alkyl group.
Examples of the alkyl group in the alkyl group and the alkyl group having a phosphonic acid group represented by Z ¹ to Z ⁵ include a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 1 to 4 carbon atoms, and a methyl group is preferable.
The number of phosphonic acid groups in the alkyl groups having a phosphonic acid group represented by Z ¹ to Z ⁵ is preferably 1 or 2, and more preferably 1.
Examples of the alkyl group having a phosphonic acid group represented by Z ¹ to Z ⁵ include linear or branched alkyl groups having 1 to 4 carbon atoms and having one or two phosphonic acid groups, and are preferably a (mono)phosphonomethyl group or a (mono)phosphonoethyl group, and more preferably a (mono)phosphonomethyl group.
It is preferable that Z ¹ to Z ⁵ , Z ¹ to Z ⁴ and all of the n Z ^5s are the above-mentioned alkyl group having a phosphonic acid group.

As the compound represented by formula (P3), diethylenetriaminepenta(methylenephosphonic acid) (DEPPO), diethylenetriaminepenta(ethylenephosphonic acid), triethylenetetraminehexa(methylenephosphonic acid), or triethylenetetraminehexa(ethylenephosphonic acid) is preferred.

As complexing agents having a phosphonic acid group, the compounds described in paragraphs [0026] to [0036] of WO 2018/020878 and the compounds ((co)polymers) described in paragraphs [0031] to [0046] of WO 2018/030006 can be used, the contents of which are incorporated herein by reference.

The carbon number of the complexing agent having a phosphonic acid group is preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less. There is no particular lower limit, and it is preferably 1 or more, and more preferably 2 or more.
As the complexing agent having a phosphonic acid group, the compound represented by the above formula (P1), the compound represented by the formula (P2), or the compound represented by the formula (P3) is preferred, and HEDPO is more preferred.

The specific complexing agent preferably includes at least one selected from the group consisting of a compound represented by formula (B1), a compound represented by formula (B2), a compound represented by formula (B4), a compound represented by formula (C), a complexing agent having a phosphate group, and a compound represented by formula (P1), more preferably includes at least one selected from the group consisting of a compound represented by formula (B1), a compound represented by formula (B3), a compound represented by formula (B4), a compound represented by formula (C), diphosphate, hexametaphosphate, phytic acid, and a compound represented by formula (P1), and even more preferably includes at least one selected from the group consisting of a compound represented by formula (B1), a compound represented by formula (C), phytic acid, and a compound represented by formula (P1).

The specific complexing agent may form a salt.
Examples of the salt include alkali metal salts such as sodium salts and potassium salts, ammonium salts, hydrochlorides, carbonates, and acetates.

The molecular weight of the specific complexing agent is preferably not more than 600, more preferably not more than 450, and even more preferably not more than 300. There is no particular lower limit to the molecular weight, and it is preferably 50 or more.
The carbon number of the specific complexing agent is preferably 15 or less, and more preferably 10 or less. There is no particular lower limit to the carbon number, and it is preferably 2 or more.

The specific complexing agent may be used alone or in combination of two or more.
The mass ratio of the content of the specific complexing agent to the content of the alkanolamine [content of specific complexing agent/content of alkanolamine] is preferably 0.1 to 2000.0, more preferably 0.1 to 1850.0, even more preferably 0.1 to 1500.0, still more preferably 0.1 to 1000.0, particularly preferably 0.1 to 400.0, and most preferably 20.0 to 400.0.
The mass ratio of the content of the specific complexing agent to the content of the polymer [content of specific complexing agent/content of polymer] is preferably from 0.03 to 200.0, more preferably from 1.0 to 100.0, and even more preferably from 1.5 to 50.0.

〔water〕
The cleaning liquid contains water as a solvent.
The water is not particularly limited as long as it does not adversely affect the semiconductor substrate, and distilled water, deionized water, and pure water (preferably ultrapure water) can be used.
The water is preferably pure water or ultrapure water, since it contains almost no impurities and has less effect on the semiconductor substrate during the manufacturing process of the semiconductor substrate.

The content of water may be the balance of the components contained in the cleaning liquid.
The water content is preferably 1.0% by mass or more, more preferably 30.0% by mass or more, even more preferably 60.0% by mass or more, and particularly preferably 85.0% by mass or more, based on the total mass of the cleaning solution. There is no particular upper limit, and the water content is preferably 99.0% by mass or less, more preferably 97.0% by mass or less, based on the total mass of the cleaning solution.

[Surfactant]
The cleaning solution may contain a surfactant.
The surfactant is a compound different from the components contained in the cleaning solution described above.
A surfactant is a compound having a hydrophilic group and a hydrophobic group (lipophilic group) in one molecule. Examples of surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.
The surfactant preferably contains an anionic surfactant, more preferably contains a phosphate surfactant, further preferably contains at least one selected from the group consisting of an alkyl phosphate ester and a polyoxyethylene alkyl phosphate ester, and particularly preferably contains an alkyl phosphate ester.
When the cleaning liquid contains a surfactant, the corrosion suppression performance of the metal film and the cleaning performance of the abrasive particles can be improved.

The surfactant often has a hydrophobic group selected from the group consisting of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and combinations thereof.
The hydrophobic group of the surfactant is not particularly limited, but when the hydrophobic group contains an aromatic hydrocarbon group, it preferably has 6 or more carbon atoms, and more preferably has 10 or more carbon atoms. When the hydrophobic group does not contain an aromatic hydrocarbon group and is composed only of an aliphatic hydrocarbon group, it preferably has 9 or more carbon atoms, and more preferably has 12 or more carbon atoms. There is no particular upper limit on the number of carbon atoms of the hydrophobic group, but it is preferably 20 or less, and more preferably 18 or less. The total carbon number of the surfactant is preferably 16 to 100.

<Anionic Surfactant>
Examples of the anionic surfactant include phosphate ester surfactants having a phosphate group, phosphonic acid surfactants having a phosphonic acid group, sulfonic acid surfactants having a sulfonic acid group, carboxylic acid surfactants having a carboxy group, and sulfate ester surfactants having a sulfate group.

(Phosphate ester surfactant)
Examples of phosphate surfactants include alkyl phosphates, polyoxyalkylene alkyl ether phosphates, and salts thereof.
Among these, alkyl phosphate esters are preferred.

The phosphate ester and polyoxyalkylene alkyl ether phosphate ester may be a single monoester or diester, or a mixture of a monoester and a diester.
Examples of salts of the phosphate ester surfactant include sodium salts, potassium salts, ammonium salts, and organic amine salts.
The alkyl group contained in the alkyl phosphate ester and the polyoxyalkylene alkyl ether phosphate ester is preferably an alkyl group having 2 to 24 carbon atoms, more preferably an alkyl group having 6 to 18 carbon atoms, and even more preferably an alkyl group having 12 to 18 carbon atoms.
The alkylene group contained in the polyoxyalkylene alkyl ether phosphate ester is preferably an alkylene group having 2 to 6 carbon atoms, and more preferably an ethylene group or a 1,2-propanediyl group.
The number of repetitions of the oxyalkylene group in the polyoxyalkylene ether phosphate is preferably 1-12, and more preferably 1-10.

As the phosphate surfactant, octyl phosphate, lauryl phosphate, tridecyl phosphate, myristyl phosphate, cetyl phosphate, stearyl phosphate, polyoxyethylene octyl ether phosphate, polyoxyethylene lauryl ether phosphate, polyoxyethylene tridecyl ether phosphate, or polyoxyethylene myristyl ether phosphate is preferred, lauryl phosphate, tridecyl phosphate, myristyl phosphate, cetyl phosphate, stearyl phosphate, or polyoxyethylene myristyl ether phosphate is more preferred, and lauryl phosphate, cetyl phosphate, stearyl phosphate, or polyoxyethylene myristyl ether phosphate is even more preferred.

As phosphate ester surfactants, the compounds described in paragraphs [0012] to [0019] of JP 2011-040502 A can also be used, the contents of which are incorporated herein by reference.

(Phosphonic acid surfactant)
Examples of phosphonic acid surfactants include alkylphosphonic acids, polyvinylphosphonic acids, and aminomethylphosphonic acids described in JP 2012-057108 A.

(Sulfonic acid surfactant)
Examples of sulfonic acid surfactants include alkyl sulfonic acids, alkyl benzene sulfonic acids, alkyl naphthalene sulfonic acids, alkyl diphenyl ether disulfonic acids, alkyl methyl taurines, sulfosuccinic acid diesters, polyoxyalkylene alkyl ether sulfonic acids, and salts thereof.

The alkyl group contained in the sulfonic acid surfactant is preferably an alkyl group having 2 to 24 carbon atoms, and more preferably an alkyl group having 6 to 18 carbon atoms.
The alkylene group contained in the polyoxyalkylene alkyl ether sulfonic acid is preferably an ethylene group or a 1,2-propanediyl group.
The number of repetitions of the oxyalkylene group in the polyoxyalkylene alkyl ether sulfonic acid is preferably 1 to 12, and more preferably 1 to 6.

Examples of sulfonic acid surfactants include hexanesulfonic acid, octanesulfonic acid, decanesulfonic acid, dodecanesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid (DBSA), dinitrobenzenesulfonic acid (DNBSA), and lauryldodecylphenyletherdisulfonic acid (LDPEDSA).
Of these, dodecanesulfonic acid, DBSA, DNBSA, or LDPEDSA is preferred, and DBSA, DNBSA, or LDPEDSA is more preferred.

(Carboxylic acid surfactant)
Examples of the carboxylic acid surfactant include alkyl carboxylic acids, alkyl benzene carboxylic acids, and polyoxyalkylene alkyl ether carboxylic acids, as well as salts thereof.

The alkyl group contained in the carboxylic acid surfactant is preferably an alkyl group having 7 to 25 carbon atoms, and more preferably an alkyl group having 11 to 17 carbon atoms.
The alkylene group contained in the polyoxyalkylene alkyl ether carboxylic acid is preferably an ethylene group or a 1,2-propanediyl group.
The number of repetitions of the oxyalkylene group in the polyoxyalkylene alkyl ether carboxylic acid is preferably 1 to 12, and more preferably 1 to 6.

Examples of carboxylic acid surfactants include lauric acid, myristic acid, palmitic acid, stearic acid, polyoxyethylene lauryl ether acetic acid, and polyoxyethylene tridecyl ether acetic acid.

(Sulfate ester surfactant)
Examples of sulfate surfactants include alkyl sulfates and polyoxyalkylene alkyl ether sulfates, as well as salts thereof.

The alkyl group contained in the alkyl sulfate and polyoxyalkylene alkyl ether sulfate is preferably an alkyl group having 2 to 24 carbon atoms, more preferably an alkyl group having 6 to 18 carbon atoms.
The alkylene group contained in the polyoxyalkylene alkyl ether sulfate is preferably an ethylene group or a 1,2-propanediyl group.
The number of repetitions of the oxyalkylene group in the polyoxyalkylene alkyl ether sulfate is preferably 1 to 12, and more preferably 1 to 6.

Examples of sulfate surfactants include lauryl sulfate, myristyl sulfate, and polyoxyethylene lauryl ether sulfate.

As surfactants, for example, the compounds described in paragraphs [0092] to [0096] of JP 2015-158662 A, paragraphs [0045] to [0046] of JP 2012-151273 A, and paragraphs [0014] to [0020] of JP 2009-147389 A can also be used, the contents of which are incorporated herein by reference.

The surfactant may be used alone or in combination of two or more kinds.
The content of the surfactant is preferably 0.001 to 8.0 mass %, more preferably 0.005 to 5.0 mass %, and even more preferably 0.01 to 3.0 mass %, based on the total mass of the cleaning liquid, in order to provide a well-balanced and excellent performance of the cleaning liquid.
The content of the surfactant is preferably from 1.0 to 30.0% by mass, more preferably from 5.0 to 20.0% by mass, and even more preferably from 10.0 to 20.0% by mass, based on the total mass of the cleaning liquid excluding the solvent.

[Corrosion inhibitor]
The cleaning liquid may contain a corrosion inhibitor.
Examples of the corrosion inhibitor include carboxylic acids, heterocyclic compounds having a heterocyclic structure in the molecule, catechol compounds, hydroxylamine compounds, biguanide compounds, hydrazide compounds, ascorbic acid compounds, reducing sulfur compounds, and polyhydroxy compounds having a molecular weight of 500 or more.

<Carboxylic Acid>
A carboxylic acid is a compound having a carboxy group in the molecule.
The carboxylic acid is a compound different from the components contained in the cleaning solution described above.
Examples of carboxylic acids include propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, and 2-ethylhexanoic acid.

<Heterocyclic compounds>
A heterocyclic compound is a compound that has a heterocyclic structure in the molecule.
The heterocyclic compound is a compound different from the components contained in the cleaning solution described above.
The heterocyclic structure of the heterocyclic compound can be, for example, a heterocycle in which at least one of the atoms constituting the ring is a nitrogen atom (nitrogen-containing heterocycle).
Examples of the heterocyclic compound having a nitrogen-containing heterocycle include azole compounds, pyridine compounds, pyrazine compounds, pyrimidine compounds, piperazine compounds, and cyclic amidine compounds.
Among them, the heterocyclic compound is preferably at least one selected from the group consisting of azole compounds, pyridine compounds, pyrazine compounds, and pyrimidine compounds.

The azole compound is a compound having at least one nitrogen atom and a five-membered heterocyclic ring having aromaticity.
The number of nitrogen atoms contained in the five-membered hetero ring of the azole compound is preferably 1 to 4, and more preferably 1 to 3.
The azole compound may have a substituent on the 5-membered hetero ring. Examples of the substituent include a hydroxyl group, a carboxy group, a mercapto group, an amino group, an alkyl group having 1 to 4 carbon atoms which may have an amino group, and a 2-imidazolyl group.

Examples of azole compounds include imidazole compounds in which one of the atoms constituting the azole ring is a nitrogen atom, pyrazole compounds in which two of the atoms constituting the azole ring are nitrogen atoms, thiazole compounds in which one of the atoms constituting the azole ring is a nitrogen atom and the other is a sulfur atom, triazole compounds in which three of the atoms constituting the azole ring are nitrogen atoms, and tetrazole compounds in which four of the atoms constituting the azole ring are nitrogen atoms.

Examples of imidazole compounds include imidazole, 1-methylimidazole, 2-methylimidazole, 5-methylimidazole, 1,2-dimethylimidazole, 2-mercaptoimidazole, 4,5-dimethyl-2-mercaptoimidazole, 4-hydroxyimidazole, 2,2'-biimidazole, 4-imidazolecarboxylic acid, histamine, benzimidazole, and purine bases (such as adenine).

Examples of pyrazole compounds include pyrazole, 4-pyrazole carboxylic acid, 1-methylpyrazole, 3-methylpyrazole, 3-amino-5-methylpyrazole, 3-amino-5-hydroxypyrazole, 3-aminopyrazole, and 4-aminopyrazole.

Examples of thiazole compounds include 2,4-dimethylthiazole, benzothiazole, and 2-mercaptobenzothiazole.

Examples of triazole compounds include 1,2,4-triazole, 3-methyl-1,2,4-triazole, 3-amino-1,2,4-triazole, 1,2,3-triazole, 1-methyl-1,2,3-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxybenzotriazole, 5-methylbenzotriazole, and 2,2'-{[(5-methyl-1H-benzotriazol-1-yl)methyl]imino}diethanol.

Examples of tetrazole compounds include 1H-tetrazole (1,2,3,4-tetrazole), 5-methyl-1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, and 1-(2-dimethylaminoethyl)-5-mercaptotetrazole.

As the azole compound, at least one selected from the group consisting of imidazole compounds, pyrazole compounds, thiazole compounds, triazole compounds, and tetrazole compounds is preferred, and imidazole, pyrazole, 2,4-dimethylthiazole, 1,2,4-triazole, 1H-tetrazole (1,2,3,4-tetrazole), or adenine is more preferred.

The pyridine compound is a compound having one nitrogen atom and a six-membered heterocyclic ring (pyridine ring) having aromaticity.
The pyridine compound may have a substituent on the pyridine ring, for example, a hydroxyl group, an amino group, a cyano group, an alkyl group having 1 to 4 carbon atoms, and an alkylamide group having 1 to 4 carbon atoms.

Examples of pyridine compounds include pyridine, 3-aminopyridine, 4-aminopyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-acetamidopyridine, 2-cyanopyridine, 2-carboxypyridine, and 4-carboxypyridine, with pyridine being preferred.

The pyrazine compound is an aromatic compound having a six-membered hetero ring (pyrazine ring) containing two nitrogen atoms located at the para position.
The pyrimidine compound is an aromatic compound having a six-membered hetero ring (pyrimidine ring) containing two nitrogen atoms located at the meta positions.
The pyrazine compound and pyrimidine compound may have a substituent on the ring, for example, a hydroxyl group, an amino group, a carboxyl group, and an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group.

Examples of pyrazine compounds include pyrazine, 2-methylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, 2,3,5,6-tetramethylpyrazine, 2-ethyl-3-methylpyrazine, and 2-amino-5-methylpyrazine, with pyrazine being preferred.

Examples of pyrimidine compounds include pyrimidine, 2-methylpyrimidine, 2-aminopyrimidine, and 4,6-dimethylpyrimidine, with pyrimidine being preferred.

The piperazine compound is a compound having a six-membered hetero ring (piperazine ring) in which opposing --CH-- groups of a cyclohexane ring are replaced with nitrogen atoms.
The piperazine compound may have a substituent on the piperazine ring, for example, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and an aryl group having 6 to 10 carbon atoms.

Examples of piperazine compounds include piperazine, 1-methylpiperazine, 1-ethylpiperazine, 1-propylpiperazine, 1-butylpiperazine, 2-methylpiperazine, 1,4-dimethylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethylpiperazine, 1-phenylpiperazine, 2-hydroxypiperazine, 2-hydroxymethylpiperazine, 1-(2-hydroxyethyl)piperazine (HEP), and 1,4-bis(3-aminopropyl)piperazine (BAP). Piperazine, 1-methylpiperazine, 2-methylpiperazine, HEP, or BAP is preferred, and HEP or BAP is more preferred.

A cyclic amidine compound is a compound having a heterocycle containing an amidine structure (>N-C=N-) in the ring.
The number of ring members in the hetero ring of the cyclic amidine compound is preferably 5 to 6, and more preferably 6.
The cyclic amidine compound may have a substituent on the heterocycle. Examples of the substituent include an amino group, an oxo group, and an alkyl group having 1 to 4 carbon atoms. In addition, two substituents on the heterocycle may be bonded to each other to form a divalent linking group (preferably an alkylene group having 3 to 6 carbon atoms).

Examples of cyclic amidine compounds include diazabicycloundecene (1,8-diazabicyclo[5.4.0]undec-7-ene: DBU), diazabicyclononene (1,5-diazabicyclo[4.3.0]non-5-ene: DBN), 3,4,6,7,8,9,10,11-octahydro-2H-pyrimido[1.2-a]azocine, 3,4,6,7,8,9-hexahydro-2H-pyrimido[1.2-a]pyrimidine, 2,5,6,7-tetrahydro-3H-pyrrolo[1.2-a]imidazole, 3-ethyl-2,3,4,6,7,8,9,10-octahydropyrimido[1.2-a]azepine, and creatinine, with DBU or DBN being preferred.

Examples of heterocyclic compounds include compounds having a non-aromatic five-membered heterocyclic ring, such as 1,3-dimethyl-2-imidazolidinone and imidazolidinethione, as well as compounds having a seven-membered ring containing a nitrogen atom.

Examples of compounds having a seven-membered ring containing a nitrogen atom include hexahydro-1H-1,4-diazepine, 1-methylhexahydro-1H-1,4-diazepine, 2-methylhexahydro-1H-1,4-diazepine, 6-methylhexahydro-1H-1,4-diazepine, 2,7-diazabicyclo[3.2.1]octane, and 1,3-diazabicyclo[3.2.2]nonane.

<Catechol Compounds>
The catechol compound means at least one selected from the group consisting of pyrocatechol (benzene-1,2-diol) and catechol derivatives.
The catechol derivative means a compound in which pyrocatechol is substituted with at least one substituent.
The catechol compound is a compound different from the components contained in the cleaning solution described above.
Examples of the substituents that the catechol derivatives have include a hydroxyl group, a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, an alkyl group (preferably having 1 to 6 carbon atoms, and more preferably having 1 to 4 carbon atoms), and an aryl group (preferably a phenyl group).
The carboxyl group and sulfo group contained in the catechol derivative as a substituent may be a salt with a cation. The alkyl group and aryl group contained in the catechol derivative as a substituent may further have a substituent.

Examples of catechol compounds include pyrocatechol, 4-tert-butylcatechol, pyrogallol, gallic acid, methyl gallate, 1,2,4-benzenetriol, and tiron. Of these, pyrocatechol, pyrogallol, and gallic acid are preferred.

<Hydroxylamine Compounds>
The hydroxylamine compound means at least one selected from the group consisting of hydroxylamine (NH ₂ OH), hydroxylamine derivatives, and salts thereof.
The hydroxylamine compound is a compound different from the components contained in the cleaning solution described above.
The hydroxylamine derivative means a compound in which at least one organic group is substituted on hydroxylamine (NH ₂ OH).
Salts of hydroxylamine or hydroxylamine derivatives include inorganic acid salts and organic acid salts.
Among these, as the salt of hydroxylamine or a hydroxylamine derivative, a salt with an inorganic acid formed by combining at least one nonmetal selected from the group consisting of Cl, S, N, and P with hydrogen is preferred, and a hydrochloride, sulfate, or nitrate is more preferred.

Examples of hydroxylamine compounds include compounds represented by general formula (5).

In formula (5), R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

The alkyl group having 1 to 6 carbon atoms represented by R ⁶ and R ⁷ may be linear, branched, or cyclic.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclobutyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a 2-methylbutyl group, a 1,2-dimethylpropyl group, a 1-ethylpropyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a 2-methylpentyl group, a 1,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a 1-ethylbutyl group, and a cyclohexyl group.
Among these, R ⁶ and R ⁷ are preferably an alkyl group having 1 to 6 carbon atoms, more preferably an ethyl group or an n-propyl group, and even more preferably an ethyl group.

Examples of the hydroxylamine compound include hydroxylamine, N-methylhydroxylamine, N,N-dimethylhydroxylamine, N-ethylhydroxylamine, N,N-diethylhydroxylamine (DEHA), N-n-propylhydroxylamine, N,N-di-n-propylhydroxylamine, N-isopropylhydroxylamine, N,N-diisopropylhydroxylamine, N-n-butylhydroxylamine, N,N-di-n-butylhydroxylamine, N-isobutylhydroxylamine, N,N-diisobutylhydroxylamine, N-sec-butylhydroxylamine, N,N-di-sec-butylhydroxylamine, and N-tert-butylhydroxylamine. N-tert-butylhydroxylamine, N-cyclobutylhydroxylamine, N,N-dicyclobutylhydroxylamine, N-n-pentylhydroxylamine, N,N-di-n-pentylhydroxylamine, N-isopentylhydroxylamine, N,N-diisopentylhydroxylamine, N-sec-pentylhydroxylamine, N,N-di-sec-pentylhydroxylamine, N-tert-pentylhydroxylamine, N,N-di-tert-pentylhydroxylamine, N-neopentylhydroxylamine, N,N-dineopentylhydroxylamine, N-2-methylbutylhydroxylamine, N,N-bis( 2-methylbutyl)hydroxylamine, N-1,2-dimethylpropylhydroxylamine, N,N-bis(1,2-dimethylpropyl)hydroxylamine, N-1-ethylpropylhydroxylamine, N,N-bis(1-ethylpropyl)hydroxylamine, N-cyclopentylhydroxylamine, N,N-dicyclopentylhydroxylamine, N-n-hexylhydroxylamine, N,N-di-n-hexylhydroxylamine, N-isohexylhydroxylamine, N,N-diisohexylhydroxylamine, N-sec-hexylhydroxylamine, N,N-di-sec-hexylhydroxylamine, N-tert-hexylhydroxylamine, N,N -di-tert-hexylhydroxylamine, N-neohexylhydroxylamine, N,N-dineohexylhydroxylamine, N-2-methylpentylhydroxylamine, N,N-bis(2-methylpentyl)hydroxylamine, N-1,2-dimethylbutylhydroxylamine, N,N-bis(1,2-dimethylbutyl)hydroxylamine, N-2,3-dimethylbutylhydroxylamine, N,N-bis(2,3-dimethylbutyl)hydroxylamine, N-1-ethylbutylhydroxylamine, N,N-bis(1-ethylbutyl)hydroxylamine, N-cyclohexylhydroxylamine, and N,N-dicyclohexylhydroxylamine.
Of these, the hydroxylamine compound is preferably hydroxylamine, N-ethylhydroxylamine, DEHA, or Nn-propylhydroxylamine, and more preferably hydroxylamine.
The hydroxylamine compound to be used may be a commercially available product, or may be appropriately synthesized by a known method.

<Biguanide Compounds>
The biguanide compounds include compounds having a biguanide group and biguanide compounds which are salts thereof.
The biguanide compound may have one or more biguanide groups.
Examples of the biguanide compound include the compounds described in paragraphs [0034] to [0055] of JP-A No. 2017-504190, the contents of which are incorporated herein by reference.

Examples of compounds having a biguanide group include ethylene dibiguanide, propylene dibiguanide, tetramethylene dibiguanide, pentamethylene dibiguanide, hexamethylene dibiguanide, heptamethylene dibiguanide, octamethylene dibiguanide, 1,1'-hexamethylenebis(5-(p-chlorophenyl)biguanide) (chlorhexidine), 2-(benzyloxymethyl)pentane-1,5-bis(5-hexylbiguanide), 2-(phenyl [0113] 3-(phenylthio)hexane-1,6-bis(5-hexylbiguanide), 3-(phenylthio)hexane-1,6-bis(5-cyclohexylbiguanide), 3-(benzylthio)hexane-1,6-bis(5-hexylbiguanide), or 3-(benzylthio)hexane-1,6-bis(5-cyclohexylbiguanide) is preferred, and chlorhexidine is more preferred.
As the salt of the compound having a biguanide group, hydrochloride, acetate or gluconate is preferred, and gluconate is more preferred.
A preferred biguanide compound is chlorhexidine gluconate (CHG).

<Hydrazide compounds>
The hydrazide compound means a compound in which the hydroxyl group of an acid is replaced with a hydrazino group (-NH-NH ₂ ), and its derivatives (compounds in which the hydrazino group is substituted with at least one substituent).
The hydrazide compound may have one or more hydrazino groups.
Examples of the hydrazide compound include carboxylic acid hydrazide and sulfonic acid hydrazide, with carbohydrazide (CHZ) being preferred.

<Ascorbic acid compounds>
The ascorbic acid compound means at least one selected from the group consisting of ascorbic acid, ascorbic acid derivatives, and salts thereof.
Examples of ascorbic acid derivatives include ascorbic acid phosphate and ascorbic acid sulfate.
Among these, ascorbic acid, ascorbic acid is preferred.

<Reduced sulfur compounds>
The reducible sulfur compound is a compound that has reducing properties and contains a sulfur atom.
Examples of reducing sulfur compounds include thioglycolic acid, dithiodiglycolic acid, bis(2,3-dihydroxypropylthio)ethylene, sodium 3-(2,3-dihydroxypropylthio)-2-methyl-propylsulfonate, 1-thioglycerol, 2-mercaptoethanol, and 3-mercapto-1-propanol.
Among these, compounds having an SH group (mercapto compounds) are preferred, and thioglycolic acid or dithiodiglycolic acid is more preferred.

<Polyhydroxy Compound with Molecular Weight of 500 or More>
The polyhydroxy compound is an organic compound having two or more (eg, 2 to 200) alcoholic hydroxyl groups in one molecule.
The polyhydroxy compound is a compound different from the components contained in the cleaning solution described above.
The molecular weight of the polyhydroxy compound (meaning the weight average molecular weight when the compound has a molecular weight distribution) is 500 or more, and preferably 500 to 3,000.

Examples of the polyhydroxy compounds include polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene glycol; oligosaccharides such as manninotriose, cellotriose, gentianose, raffinose, melezitose, cerotetrose, and stachyose; polysaccharides such as starch, glycogen, cellulose, chitin, and chitosan, and hydrolysates thereof, with polyethylene glycol being preferred.

Cyclodextrin is also a preferred example of the polyhydroxy compound.
Cyclodextrin is a type of cyclic oligosaccharide in which multiple D-glucose units are bonded together through glycosidic bonds to form a ring structure. For example, there is a compound in which five or more glucose units (e.g., six to eight) are bonded together.
Examples of cyclodextrin include α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, with γ-cyclodextrin being preferred.

The corrosion inhibitor preferably contains at least one selected from the group consisting of catechol compounds, heterocyclic compounds, hydroxyamine compounds, biguanide compounds, ascorbic acid, reducing sulfur compounds, and polyhydroxy compounds having a molecular weight of 500 or more, and more preferably contains a heterocyclic compound.

The anticorrosive agent may be used alone or in combination of two or more kinds.
The content of the anticorrosive agent is preferably 0.01 to 10.0 mass %, more preferably 0.05 to 5.0 mass %, and even more preferably 0.05 to 3.0 mass %, based on the total mass of the cleaning liquid.
The content of the anticorrosive agent is preferably 0.2 to 20.0 mass %, more preferably 1.0 to 10.0 mass %, and even more preferably 1.5 to 5.0 mass %, based on the total mass of the cleaning liquid excluding the solvent.

〔Preservative〕
The cleaning solution may contain a preservative.
The preservative is a compound different from the components contained in the cleaning solution described above.
Examples of preservatives include benzoic acid, sodium benzoate, salicylic acid, propionic acid, isopropyl parahydroxybenzoate, isobutyl parahydroxybenzoate, ethyl parahydroxybenzoate, methyl parahydroxybenzoate, butyl parahydroxybenzoate, propyl parahydroxybenzoate, sodium sulfite, sodium hyposulfite, potassium metabisulfite, sorbic acid, potassium sorbate, sodium dehydroacetate, thujaplicin, Aralia udo extract, Styrax japonica extract, Artemisia capillaris extract, oolong tea extract, white milt protein extract, enzymatically hydrolyzed Job's tears extract, tea catechins, apple polyphenols, pectin hydrolyzates, chitosan, lysozyme, and ε-polylysine.
Among these, the preservative is preferably benzoic acid, sorbic acid, salicylic acid, or propionic acid.

Benzoic acid, sorbic acid, salicylic acid, and propionic acid may also be used as pH adjusters and metal dissolving agents as described below.

The preservatives may be used alone or in combination of two or more kinds.
The content of the preservative is preferably 0.01 to 10.0 mass %, more preferably 0.05 to 5.0 mass %, and even more preferably 0.05 to 3.0 mass %, based on the total mass of the cleaning solution.
The content of the anticorrosive agent is preferably 0.2 to 20.0 mass %, more preferably 1.0 to 10.0 mass %, and even more preferably 1.5 to 5.0 mass %, based on the total mass of the cleaning liquid excluding the solvent.

The cleaning solution preferably contains at least one selected from the group consisting of a surfactant, an anticorrosive agent, and a preservative, more preferably contains at least one selected from the group consisting of a surfactant and an anticorrosive agent, even more preferably contains an anticorrosive agent, and particularly preferably contains a heterocyclic compound.

〔Oxidant〕
The cleaning solution may contain an oxidizing agent.
The oxidizing agent is a compound different from the components contained in the cleaning solution described above.
Oxidizing agents include, for example, peroxides, persulfides (such as monopersulfides and dipersulfides), percarbonates, acids thereof, and salts thereof.
Examples of the oxidizing agent include oxide halides (periodic acids such as iodic acid, metaperiodic acid, and orthoperiodic acid, and salts thereof, etc.), perboric acid, perborates, cerium compounds, and ferricyanides (potassium ferricyanide, etc.).

The oxidizing agent may be used alone or in combination of two or more kinds.
The content of the oxidizing agent is preferably from 0.01 to 10 mass %, more preferably from 0.05 to 5 mass %, and even more preferably from 0.1 to 3 mass %, based on the total mass of the cleaning liquid.

[pH adjuster]
The cleaning solution may include a pH adjuster to adjust and maintain the pH of the cleaning solution.
The pH adjuster is a compound different from the components contained in the cleaning solution described above.
Examples of pH adjusters include quaternary ammonium compounds, basic compounds, and acidic compounds.
Among these, quaternary ammonium compounds, sulfuric acid, or potassium hydroxide are preferred.
However, it is permissible to adjust the pH of the cleaning solution by adjusting the amount of each of the above-mentioned components added.

The quaternary ammonium compound is a compound different from the components contained in the cleaning solution described above.
The quaternary ammonium compound is preferably a compound having a quaternary ammonium cation in which four hydrocarbon groups (preferably alkyl groups) are substituted on a nitrogen atom.The quaternary ammonium compound may also be a compound having a quaternary ammonium cation in which a nitrogen atom in a pyridine ring is bonded to a substituent (such as an alkyl group or an aryl group, etc.), such as an alkylpyridinium.
Examples of quaternary ammonium compounds include quaternary ammonium hydroxides, quaternary ammonium fluorides, quaternary ammonium bromides, quaternary ammonium iodides, quaternary ammonium acetates, and quaternary ammonium carbonates.

The quaternary ammonium compound is preferably a quaternary ammonium hydroxide represented by formula (4).
( ^R8 ) _4N ^{+ OH-} (4)
In formula (4), ^R8 represents an alkyl group which may have a hydroxyl group or a phenyl group as a substituent. The four ^R8s may be the same or different from each other.

The alkyl group represented by R ⁸ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group.
The alkyl group which may have a hydroxyl group or a phenyl group, represented by ^R8 , is preferably a methyl group, an ethyl group, a propyl group, a butyl group, a 2-hydroxyethyl group, or a benzyl group, more preferably a methyl group, an ethyl group, a propyl group, a butyl group, or a 2-hydroxyethyl group, and even more preferably a methyl group, an ethyl group, or a 2-hydroxyethyl group.

Examples of quaternary ammonium compounds include tetramethylammonium hydroxide (TMAH), trimethylethylammonium hydroxide (TMEAH), dimethyldiethylammonium hydroxide (DMDEAH), methyltriethylammonium hydroxide (MTEAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), 2-hydroxyethyltrimethylammonium hydroxide (choline), bis(2-hydroxyethyl)dimethylammonium hydroxide, tri(2-hydroxyethyl)methylammonium hydroxide, tetra(2-hydroxyethyl)ammonium hydroxide, benzyltrimethylammonium hydroxide (BTMAH), and cetyltrimethylammonium hydroxide.
As the quaternary ammonium compound, for example, the compounds described in paragraph [0021] of JP-A-2018-107353 can be used, the contents of which are incorporated herein by reference.
Among these, the quaternary ammonium compound is preferably TMAH, TEAH, choline, TBAH, MTEAH, DMDEAH, or TPAH, and more preferably TMAH, TEAH, or choline.

The quaternary ammonium compound preferably has an asymmetric structure because it has excellent damage resistance. The quaternary ammonium compound "has an asymmetric structure" means that the four hydrocarbon groups substituted on the nitrogen atoms are not the same.
Examples of quaternary ammonium compounds having an asymmetric structure include TMEAH, DEDMAH, TEMAH, choline, and bis(2-hydroxyethyl)dimethylammonium hydroxide.

The basic compound includes a basic organic compound and a basic inorganic compound.
Examples of basic organic compounds include amine oxides, nitro, nitroso, oximes, ketoximes, aldoximes, lactams, isocyanides, and ureas.
Examples of basic inorganic compounds include alkali metal hydroxides, alkaline earth metal hydroxides, and ammonia.
Alkali metal hydroxides include, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, and cesium hydroxide.
Alkaline earth metal hydroxides include, for example, calcium hydroxide, strontium hydroxide, and barium hydroxide.

Examples of the acidic compound include inorganic acids.
As the acidic compound, a salt of an acidic compound may be used as long as it becomes an acid or an acid ion (anion) in an aqueous solution.

Examples of inorganic acids include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, boric acid, and hexafluorophosphoric acid.

The inorganic acid may form a salt.
Examples of the salt of an inorganic acid include ammonium salts of an inorganic acid, and specific examples thereof include ammonium chloride, ammonium sulfate, ammonium sulfite, ammonium nitrate, ammonium nitrite, ammonium phosphate, ammonium borate, and ammonium hexafluorophosphate.

The pH adjusters may be used alone or in combination of two or more.
The content of the pH adjuster is not particularly limited, and is appropriately adjusted depending on the types and amounts of other components and the intended pH of the cleaning liquid.
The content of the pH adjuster is preferably from 0.01 to 10.0% by mass, more preferably from 0.05 to 5.0% by mass, and even more preferably from 0.05 to 3.0% by mass, based on the total mass of the cleaning liquid.
The content of the pH adjuster is preferably from 0.2 to 20.0% by mass, more preferably from 1.0 to 10.0% by mass, and even more preferably from 1.5 to 5.0% by mass, based on the total mass of the cleaning liquid excluding the solvent.

[Organic solvent]
The cleaning liquid may contain an organic solvent.
The organic solvent is a compound different from the components contained in the cleaning solution described above.
As the organic solvent, any known organic solvent can be used, and a hydrophilic organic solvent is preferred.
Examples of the hydrophilic organic solvent include alcohol-based solvents, ketone-based solvents, ester-based solvents, sulfone-based solvents, sulfoxide-based solvents, nitrile-based solvents, and amide-based solvents.
Among these, the hydrophilic organic solvent is preferably an alcohol-based solvent or a nitrile-based solvent.

Examples of alcohol-based solvents include alkanediols such as alkylene glycols, alkoxy alcohols such as glycol monoethers, saturated aliphatic monohydric alcohols, unsaturated non-aromatic monohydric alcohols, and low molecular weight alcohols containing a cyclic structure.

Examples of alkanediols include glycol, 2-methyl-1,3-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-diol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, pinacol, and alkylene glycol.

Examples of alkylene glycols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, and tetraethylene glycol.

Examples of alkoxy alcohols include 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, 1-methoxy-2-butanol, and glycol monoethers.

Examples of glycol monoethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, 1-methoxy-2-propanol, 2-methoxy-1-propanol, 1-ethoxy-2-propanol, 2-ethoxy-1-propanol, propylene glycol mono n-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobenzyl ether, and diethylene glycol monobenzyl ether.

Examples of saturated aliphatic monohydric alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 2-pentanol, t-pentyl alcohol, and 1-hexanol.

Examples of unsaturated non-aromatic monohydric alcohols include allyl alcohol, propargyl alcohol, 2-butenyl alcohol, 3-butenyl alcohol, and 4-penten-2-ol.

Examples of low molecular weight alcohols containing a cyclic structure include tetrahydrofurfuryl alcohol, furfuryl alcohol, and 1,3-cyclopentanediol.

Examples of ketone solvents include acetone, propanone, cyclobutanone, cyclopentanone, cyclohexanone, diacetone alcohol, 2-butanone, 5-hexanedione, 1,4-cyclohexanedione, 3-hydroxyacetophenone, 1,3-cyclohexanedione, and cyclohexanone.

Examples of ester solvents include glycol monoesters such as ethyl acetate, ethylene glycol monoacetate, and diethylene glycol monoacetate; and glycol monoether monoesters such as propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and ethylene glycol monoethyl ether acetate.

Examples of sulfone solvents include sulfolane, 3-methylsulfolane, and 2,4-dimethylsulfolane.

An example of the sulfoxide solvent is dimethyl sulfoxide.
When a sulfoxide-based solvent is used, it is preferable to use a grade in which inorganic ions such as sulfate ions, chloride ions, or nitrate ions and metal ions are reduced, or to use the solvent after further purification.

An example of a nitrile solvent is acetonitrile.

Examples of amide solvents include N,N-dimethylformamide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, and hexamethylphosphoric triamide.

The organic solvent may be used alone or in combination of two or more kinds.
The content of the organic solvent is preferably from 0.01 to 80% by mass, more preferably from 0.01 to 50% by mass, further preferably from 0.01 to 10% by mass, particularly preferably from 0.01 to 1% by mass, based on the total mass of the cleaning liquid.

[Other ingredients]
The cleaning liquid may contain a fluorine compound.
Examples of the fluorine compound include compounds described in paragraphs [0013] to [0015] of JP-A-2005-150236, the contents of which are incorporated herein by reference.
The amount of the fluorine compound used is not particularly limited, and can be appropriately adjusted within a range that does not impair the effects of the present invention.

The content of each of the above components can be measured by known methods such as gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and ion-exchange chromatography (IC).

[Physical properties of cleaning solution]
<Metal content>
The cleaning liquid may contain metals as impurities.
The content (measured as an ion concentration) of each of the above metals (e.g., metal elements such as Fe, Co, Na, K, Cu, Mg, Mn, Li, Al, Cr, Ni, Zn, Sn, and Ag) is preferably 5 ppm by mass or less, and more preferably 1 ppm by mass or less, relative to the total mass of the cleaning solution.
In the manufacture of cutting-edge semiconductor devices, it is expected that a cleaning solution with even higher purity will be required, so the metal content is more preferably lower than 1 ppm by mass (i.e., on the order of ppb by mass or less) relative to the total mass of the cleaning solution, particularly preferably 100 ppb by mass or less, and most preferably less than 10 ppb by mass. There is no particular lower limit for the metal content, but it is preferably 0 relative to the total mass of the cleaning solution.

The content of potassium (K) is preferably 1000 ppb by mass or less, more preferably 100 ppb by mass or less, based on the total mass of the cleaning solution. The lower limit is not particularly limited, but is preferably 0.
The mass ratio of the potassium (K) content to the sodium (Na) content [(potassium content)/sodium content] is preferably 0.1 to 10.

Methods for reducing the metal content include, for example, purification treatment such as filtration using ion exchange resin or a filter at the stage of the raw materials used in producing the cleaning liquid or at the stage after the cleaning liquid is produced; using a container that is less likely to leach impurities, as described below, as a container for holding the raw materials or the produced cleaning liquid; lining the inner walls of piping with a fluororesin to prevent metal components from leaching from the piping during the production of the cleaning liquid; and distillation.

<Particles>
The cleaning liquid may contain particles.
The particle means a particle having a diameter (particle size) of 0.01 μm or more when the particle shape is considered as a sphere.

The content of particles having a particle diameter of 0.01 μm or more per 1 mL of the cleaning solution is preferably 1000 or less, more preferably 500 or less. There is no particular lower limit, and 0 is preferable.
It is also preferable that the content of particles having a particle size of 0.01 μm or more, as measured by the measuring method described below, is below the detection limit.
The particle content can be measured in the liquid phase using a commercially available measuring device that uses a laser as a light source for light scattering liquid particle measurement.

Examples of particles include particles such as dust, dirt, organic solids, and inorganic solids that are contained as impurities in the raw materials of the cleaning solution, as well as particles such as dust, dirt, organic solids, and inorganic solids that are brought in as contaminants during preparation of the cleaning solution, and which ultimately exist as particles in the cleaning solution without dissolving.
Methods for removing particles include, for example, purification treatments such as filtering, which will be described later.

The cleaning solution may also be prepared as a kit with the raw materials divided into multiple parts.

[Preparation of cleaning solution]
The cleaning solution can be prepared by a known method.
The method for producing the cleaning solution will be described in detail below.

<Liquid preparation process>
There are no particular limitations on the method for preparing the cleaning solution. For example, the cleaning solution can be produced by mixing the above-mentioned components.
The order and/or timing of mixing the above-mentioned components are not particularly limited, and for example, a method of preparing the mixture by sequentially adding a polymer, an alkanolamine, a specific complexing agent, and water to a container containing purified pure water, stirring the mixture to prepare a mixture, and then adding a pH adjuster to the mixture to adjust the pH can be mentioned. When adding water and each component to a container, they may be added all at once or may be added in several portions.

The stirring device and stirring method used to prepare the cleaning liquid are not particularly limited, and any device known as a stirrer or disperser can be used.
Examples of stirrers include industrial mixers, portable stirrers, mechanical stirrers, and magnetic stirrers.
Examples of the dispersing machine include an industrial dispersing machine, a homogenizer, an ultrasonic dispersing machine, and a bead mill.

The temperature for mixing the components in the cleaning solution preparation process, the purification process described below, and the storage temperature of the produced cleaning solution is preferably 40°C or less, more preferably 30°C or less. There is no particular lower limit for the storage temperature, and it is preferably 5°C or more, more preferably 10°C or more. By preparing, processing, and/or storing the cleaning solution within the above temperature range, the performance of the cleaning solution can be stably maintained for a long period of time.

(Refining process)
It is preferable to previously subject one or more of the raw materials for preparing the cleaning solution to a purification treatment.
Examples of purification methods include known methods such as distillation, ion exchange, and filtration.
As for the degree of purification, for example, it is preferable to purify the raw material until the purity becomes 99% by mass or more, and it is more preferable to purify the raw solution until the purity becomes 99.9% by mass or more.

Examples of the purification method include passing the raw material through an ion exchange resin or a reverse osmosis membrane (RO membrane), distilling the raw material, and filtering, which will be described later.
The purification process may be a combination of the above purification methods. For example, the raw material may be subjected to a primary purification process in which the raw material is passed through an RO membrane, and then a secondary purification process in which the raw material is passed through a purification device made of a cation exchange resin, an anion exchange resin, or a mixed-bed ion exchange resin.
The purification process may be carried out multiple times.

(filtering)
The filter used for filtering is not particularly limited as long as it is used for filtering purposes.
Examples of the filter include filters made of a material selected from the group consisting of fluororesins such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polyamide resins such as nylon, and polyolefin resins (including high density or ultra-high molecular weight) such as polyethylene and polypropylene (PP).
Among them, the filter is preferably made of a material selected from the group consisting of polyethylene, polypropylene (including high density polypropylene), fluorine-based resin (including PTFE and PFA), and polyamide-based resin (including nylon), and more preferably made of fluorine-based resin.
By filtering the raw material using a filter made of the above material, highly polar foreign matter that may cause defects can be effectively removed.

The critical surface tension of the filter is preferably 70 to 95 mN/m, and more preferably 75 to 85 mN/m. The value of the critical surface tension of the filter is a nominal value provided by the manufacturer.
By using a filter having a critical surface tension in the above range, highly polar foreign matter that may cause defects can be effectively removed.

The pore size of the filter is preferably 2 to 20 nm, and more preferably 2 to 15 nm. When it is within the above range, it is possible to reliably remove impurities and fine foreign matter such as aggregates contained in the raw material while suppressing clogging of the filtration. The above pore size can be determined by referring to the nominal value provided by the filter manufacturer.

The filtering may be performed only once, or may be performed two or more times.
When filtering is performed two or more times, the filters used may be the same or different.

Filtering is preferably carried out at 25°C or below, more preferably at room temperature (23°C) or below, and even more preferably at 20°C or below. There is no particular upper limit, and 0°C or above is preferred, more preferably 5°C or above, and even more preferably 10°C or above. When filtering is carried out within the above temperature range, the amount of particulate foreign matter and impurities dissolved in the raw material can be reduced, and foreign matter and impurities can be efficiently removed.

(container)
The cleaning solution (including the kit form) can be filled in any container and stored, transported, and used, so long as corrosiveness and other issues do not pose a problem.

The container is preferably one intended for semiconductor use, with a high degree of cleanliness within the container and capable of suppressing the elution of impurities from the inner wall of the container's storage portion into each liquid.
Examples of the container include various containers commercially available as containers for semiconductor cleaning liquids, specifically, the "Clean Bottle" series manufactured by Aicello Chemical Co., Ltd. and the "Pure Bottle" manufactured by Kodama Plastics Industry Co., Ltd.
As a container for containing a cleaning liquid, a container in which the inner wall of the container containing portion and the liquid contact parts thereof are formed of a fluorine-based resin (perfluororesin) or a metal that has been treated to prevent rust and metal elution is preferable.
The inner wall of the container is preferably formed from one or more resins selected from the group consisting of polyethylene resin, polypropylene resin, and polyethylene-polypropylene resin, or a different resin, or from a metal that has been treated to prevent rust and metal elution, such as stainless steel, Hastelloy, Inconel, or Monel.

The different resin is preferably a fluorine-based resin (perfluororesin).
When a container whose inner wall is made of a fluororesin is used, the occurrence of the problem of elution of ethylene or propylene oligomers can be suppressed compared to a container whose inner wall is made of a polyethylene resin, a polypropylene resin, or a polyethylene-polypropylene resin.
Examples of the container whose inner wall is made of a fluororesin include FluoroPure PFA composite drum manufactured by Entegris, and the containers described on page 4 of JP-A-3-502677, page 3 of WO 2004/016526, and pages 9 and 16 of WO 99/46309.

In addition to the above-mentioned fluororesin, quartz and electrolytically polished metal materials (that is, metal materials that have been electrolytically polished) are also preferably used for the inner wall of the container.
The metal material used in the production of the electrolytically polished metal material contains at least one selected from the group consisting of chromium and nickel, and the total content of chromium and nickel is preferably more than 25 mass%, more preferably 30 mass% or more, based on the total mass of the metal material.
The upper limit of the total content of chromium and nickel in the metal material is not particularly limited, but is preferably 90 mass % or less.
Examples of the metallic material include stainless steel and nickel-chromium alloy.

As a method for electrolytically polishing a metal material, a known method can be used.
Examples of the electrolytic polishing method include the methods described in paragraphs [0011] to [0014] of JP 2015-227501 A and paragraphs [0036] to [0042] of JP 2008-264929 A.

The container is preferably cleaned internally before being filled with the cleaning liquid.
The liquid used for the above-mentioned cleaning is preferably one in which the amount of metal impurities is reduced. After production, the cleaning liquid may be bottled in a container such as a gallon bottle or a coated bottle, and then transported and stored.

In order to prevent the components of the cleaning solution from changing during storage, the inside of the container may be replaced with an inert gas (such as nitrogen or argon) having a purity of 99.99995% by volume or more.
The inert gas preferably has a low moisture content. The temperature during transportation and storage may be room temperature, or from the viewpoint of preventing deterioration, may be −20° C. to 20° C.
Moreover, temperature control may be performed to achieve the above temperature.

(Clean room)
It is preferable that all of the handling, including production of the cleaning solution, opening and cleaning of the container, filling with the cleaning solution, processing analysis, and measurement are carried out in a clean room.
The clean room preferably meets the 14644-1 clean room standard, and more preferably meets any of ISO (International Organization for Standardization) Class 1, ISO Class 2, ISO Class 3, and ISO Class 4, more preferably meets ISO Class 1 or ISO Class 2, and even more preferably meets ISO Class 1.

[Uses of cleaning fluid]
The cleaning liquid is preferably used in a cleaning step for cleaning a semiconductor substrate that has been subjected to a chemical mechanical polishing (CMP) process. The cleaning liquid can also be used for cleaning a semiconductor substrate in a semiconductor substrate manufacturing process. Furthermore, the cleaning liquid can be used in a buffing process as described below.

[Items to be cleaned]
An example of an object to be cleaned with the cleaning liquid is a semiconductor substrate having a metal film containing tungsten.
In this specification, "on a semiconductor substrate" includes, for example, the front and back surfaces, side surfaces, and inside trenches of a semiconductor substrate. Also, a metal film on a semiconductor substrate includes not only a case where a metal film is directly on the surface of a semiconductor substrate, but also a case where a metal film is on a semiconductor substrate via another layer.

The metal contained in the metal film includes W (tungsten).
The metal film may contain a metal other than W. Examples of the other metal include at least one metal M selected from the group consisting of Cu (copper), Co (cobalt), Ti (titanium), Ta (tantalum), Ru (ruthenium), Cr (chromium), Hf (hafnium), Os (osmium), Pt (platinum), Ni (nickel), Mn (manganese), Cu (copper), Zr (zirconium), Mo (molybdenum), La (lanthanum), and Ir (iridium).

Examples of semiconductor substrates that are to be cleaned with the cleaning solution include substrates having metal wiring films, barrier metals, and insulating films on the surface of wafers that constitute the semiconductor substrate.

Examples of wafers constituting semiconductor substrates include wafers made of silicon-based materials such as silicon (Si) wafers, silicon carbide (SiC) wafers, and resin-based wafers containing silicon (glass epoxy wafers), as well as gallium phosphide (GaP) wafers, gallium arsenide (GaAs) wafers, and indium phosphide (InP) wafers.
Examples of silicon wafers include n-type silicon wafers doped with pentavalent atoms (e.g., phosphorus (P), arsenic (As), antimony (Sb), etc.), and p-type silicon wafers doped with trivalent atoms (e.g., boron (B), gallium (Ga), etc.).
Examples of silicon in the silicon wafer include amorphous silicon, single crystal silicon, polycrystalline silicon, and polysilicon.
Among them, the wafer is preferably a wafer made of a silicon-based material such as a silicon wafer, a silicon carbide wafer, or a resin-based wafer containing silicon (glass epoxy wafer).

The semiconductor substrate may further include an insulating film on the above-mentioned wafer.
Examples of insulating films include silicon oxide films (e.g., silicon dioxide (SiO ₂ ) film and tetraethyl orthosilicate (Si(OC ₂ H ₅ ) ₄ ) film (TEOS film), etc.), silicon nitride films (e.g., silicon nitride (Si ₃ N ₄ ) and silicon carbide nitride (SiNC), etc.), and low dielectric constant (Low-k) films (e.g., carbon-doped silicon oxide (SiOC) film and silicon carbide (SiC) film, etc.).

Examples of metal films containing tungsten (tungsten-containing films) include metal films consisting of only metallic tungsten (tungsten metal films) and metal films made of an alloy consisting of tungsten and a metal other than tungsten (tungsten alloy metal films).
Examples of the tungsten alloy metal film include a tungsten-titanium alloy metal film (WTi alloy metal film) and a tungsten-cobalt alloy metal film (WCo alloy metal film).
The tungsten-containing film can be used, for example, in a connection between a barrier metal or a via and a wiring.

The method for forming the insulating film and the tungsten-containing film on the wafer constituting the semiconductor substrate is not particularly limited as long as it is a known method.
An example of a method for forming an insulating film is a method in which a wafer constituting a semiconductor substrate is subjected to a heat treatment in the presence of oxygen gas to form a silicon oxide film, and then silane and ammonia gases are introduced to form a silicon nitride film by a chemical vapor deposition (CVD) method.
An example of a method for forming a tungsten-containing film is a method in which a circuit is formed on a wafer having the above-mentioned insulating film by a known method such as a resist, and then a tungsten-containing film and a cobalt-containing film are formed by a method such as plating and CVD.

<CMP Treatment>
CMP processing is a process for planarizing the surface of a substrate having a metal wiring film, a barrier metal, and an insulating film by a combined action of, for example, a chemical action using a polishing slurry containing polishing particles (abrasive grains) and a mechanical action by mechanical polishing.
On the surface of a semiconductor substrate that has been subjected to CMP treatment, impurities such as abrasive grains (e.g., silica and alumina, etc.) used in the CMP treatment, polished metal wiring film, and metal impurities (metal residues) derived from barrier metal may remain. In addition, organic residues derived from the CMP treatment liquid used in the CMP treatment may remain. These impurities may, for example, cause short circuits between wirings and deteriorate the electrical characteristics of the semiconductor substrate, so the semiconductor substrate that has been subjected to CMP treatment is subjected to a cleaning treatment to remove these impurities from the surface.
Examples of the semiconductor substrate that has been subjected to the CMP treatment include the substrate that has been subjected to the CMP treatment described in Journal of the Japan Society for Precision Engineering, Vol. 84, No. 3, 2018.

<Buffing process>
The surface of the semiconductor substrate, which is the object to be cleaned with the cleaning liquid, may be subjected to a buffing process after the CMP process.
Buff polishing is a process for reducing impurities on the surface of a semiconductor substrate using a polishing pad. Specifically, the surface of a semiconductor substrate that has been subjected to CMP is brought into contact with a polishing pad, and the semiconductor substrate and the polishing pad are slid relative to each other while a buff polishing composition is supplied to the contact portion. As a result, impurities on the surface of the semiconductor substrate are removed by the frictional force of the polishing pad and the chemical action of the buff polishing composition.

As the buffing composition, a known buffing composition can be appropriately used depending on the type of semiconductor substrate and the type and amount of impurities to be removed. The components contained in the buffing composition include, for example, a water-soluble polymer such as polyvinyl alcohol, water as a dispersion medium, and an acid such as nitric acid.
In one embodiment of the buff polishing treatment, it is preferable to perform the buff polishing treatment on a semiconductor substrate using the above-mentioned cleaning liquid as a buff polishing composition.
The polishing device and polishing conditions used in the buff polishing process can be appropriately selected from known devices and conditions depending on the type of semiconductor substrate and the object to be removed.
Examples of the buff polishing treatment include the treatments described in paragraphs [0085] to [0088] of WO 2017/169539, the contents of which are incorporated herein by reference.

[Method for cleaning semiconductor substrate]
The method for cleaning a semiconductor substrate is not particularly limited as long as it includes a cleaning step of cleaning a semiconductor substrate that has been subjected to a CMP process with the above-mentioned cleaning solution.

The cleaning step of cleaning the semiconductor substrate using the cleaning liquid is not particularly limited as long as it is a known method performed on a semiconductor substrate that has been subjected to CMP, and examples of such cleaning methods include scrub cleaning in which a cleaning member such as a brush is brought into physical contact with the surface of the semiconductor substrate while supplying the cleaning liquid to the semiconductor substrate to remove residues, an immersion type in which the semiconductor substrate is immersed in the cleaning liquid, a spin (drop) type in which the cleaning liquid is dropped while rotating the semiconductor substrate, and a spray (spray) type in which the cleaning liquid is sprayed. In the immersion type cleaning, it is preferable to subject the cleaning liquid in which the semiconductor substrate is immersed to ultrasonic treatment from the viewpoint of further reducing impurities remaining on the surface of the semiconductor substrate.
The washing step may be carried out once or twice or more. When washing twice or more, the same method may be repeated or different methods may be combined.

The method for cleaning semiconductor substrates may be either the single-wafer method or the batch method. The single-wafer method is a method in which semiconductor substrates are processed one by one, while the batch method is a method in which multiple semiconductor substrates are processed simultaneously.

The temperature of the cleaning solution used for cleaning the semiconductor substrate is not particularly limited as long as it is a temperature usually used in this field.
The temperature of the cleaning liquid may be room temperature (23° C.), or may be arbitrarily selected in order to improve cleaning properties and reduce damage to components.
In particular, the temperature of the cleaning solution is preferably from 10 to 60°C, and more preferably from 15 to 50°C.

The cleaning time for cleaning semiconductor substrates can be adjusted as appropriate depending on the type and content of components contained in the cleaning solution, and from the standpoint of practicality, the cleaning time is preferably 10 seconds to 2 minutes, more preferably 20 seconds to 1 minute and 30 seconds, and even more preferably 30 seconds to 1 minute.

The amount (supply rate) of cleaning solution supplied in the semiconductor substrate cleaning process is not particularly limited, but is preferably 50 to 5,000 mL/min, and more preferably 500 to 2,000 mL/min.

In cleaning semiconductor substrates, mechanical agitation methods may be used to further enhance the cleaning ability of the cleaning solution.
Examples of the mechanical agitation method include a method of circulating the cleaning liquid over the semiconductor substrate, a method of passing or spraying the cleaning liquid over the semiconductor substrate, and a method of agitating the cleaning liquid by ultrasonic or megasonic means.

After the above-mentioned cleaning of the semiconductor substrate, a step of rinsing and cleaning the semiconductor substrate with a solvent (hereinafter also referred to as a "rinsing step") may be carried out.
The rinsing step is preferably performed consecutively after the cleaning step of the semiconductor substrate, and is a step of rinsing with a rinsing solvent (rinsing liquid) for 5 seconds to 5 minutes. The rinsing step may be performed using the mechanical stirring method described above.

Examples of the rinse liquid include water (preferably deionized (DI) water), methanol, ethanol, isopropyl alcohol, N-methylpyrrolidinone, γ-butyrolactone, dimethylsulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate.
The rinse solution may also be an aqueous rinse solution having a pH above 8.0 (such as dilute aqueous ammonium hydroxide).
As a method for bringing the rinsing liquid into contact with the semiconductor substrate, the above-mentioned method for bringing the cleaning liquid into contact with the semiconductor substrate can be similarly applied.

After the rinsing step, a drying step of drying the semiconductor substrate may be performed.
Examples of the drying method include a spin drying method, a method of passing a dry gas over the semiconductor substrate, a method of heating the substrate with a heating means such as a hot plate or an infrared lamp, a Marangoni drying method, a Rotagoni drying method, an IPA (isopropyl alcohol) drying method, and combinations thereof.

The present invention will be described in more detail below with reference to examples. The materials, amounts used, and ratios shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. In other words, the scope of the present invention should not be interpreted as being limited by the examples shown below.

In the following examples, the pH of the cleaning solution was measured at 25° C. using a pH meter (manufactured by Horiba Ltd., model "F-74") in accordance with JIS Z8802-1984.
In addition, in the production of the cleaning solutions of the Examples and Comparative Examples, handling of containers, preparation, filling, storage, and analysis of the cleaning solutions were all carried out in a clean room meeting ISO class 2 or lower.

[Cleaning solution ingredients]
To prepare the cleaning solution, the following compounds were used:
All of the various components used in the examples were classified as semiconductor grade or equivalent high purity grade.

[Polymer]
Polymaleic acid (Mw = 2,000): NOF Corp., product name "Nonpol PWA-50W"
Polyacrylic acid (Mw = 5,000): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Polyacrylic acid 5,000"
Polyacrylic acid (Mw = 10,000): product name "AQUALIC HL415" manufactured by Nippon Shokubai Co., Ltd.
Acrylic acid-maleic acid copolymer (Mw = 10,000): Nippon Shokubai Co., Ltd., product name "AQUALIC TL37"
Styrene-maleic acid copolymer (Mw=10,000): product name "DKS Discoat N-10" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Polyacrylic acid (Mw = 25,000): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Polyacrylic acid 25,000"
Polyacrylic acid (Mw = 50,000): manufactured by Toagosei Co., Ltd., product name "Jurymer AC-10L"
Ammonium polyacrylate (Mw = 100,000): manufactured by Toagosei Co., Ltd., product name "Aron A-30"
Polyacrylic acid (Mw = 250,000): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Polyacrylic acid 250,000"
Polyacrylic acid (Mw = 800,000): manufactured by Toagosei Co., Ltd., product name "Jurymer AC-10H"
Polyacrylic acid (Mw = 1,000,000): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Polyacrylic acid 1,000,000"

[Alkanolamine]
Isopropanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -0.82, pKa 12.92
Monoethanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.31, pKa 9.50
Diethanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.50, pKa 8.88
Triethanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.11, pKa 7.88
Trishydroxymethylaminomethane: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.38, pKa 8.30
N-Ethylethanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.69, pKa 10.12
Monopropanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -1.12, pKa 9.96
Triisopropanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -0.07, pKa 14.37
N-Methylethanolamine: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -0.97, pKa 9.88
2-Amino-2-methyl-1-propanol: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value -0.61, pKa 9.70
2-(Dimethylamino)-2-methyl-1-propanol: Fujifilm Wako Pure Chemical Industries, Ltd., ClogP value 0.37, pKa 10.20

[Complexing Agent Having an Acid Group]
Serine: L-serine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Glycine: FUJIFILM Wako Pure Chemical Industries, Ltd. Alanine: L-alanine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Methionine: L-methionine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Histidine: L-histidine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Arginine: L-arginine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Glutamine: L-glutamine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Asparagine: L-asparagine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Aspartic acid: L Aspartic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Glutamic acid: L-glutamic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Cysteine: L-cysteine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Citric acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Tartaric acid: L-tartaric acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Succinic acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. DTPA: diethylenetriaminepentaacetic acid, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. HEDPO: 1-hydroxyethylidene-1,1-diphosphonic acid, "Dequest 2000" manufactured by Thermophos Corporation
EDTA: Ethylenediaminetetraacetic acid, manufactured by Chelest Corporation DHEG: N,N-bis(2-hydroxyethyl)glycine, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Phytic acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Sodium hexametaphosphate: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Diphosphate: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. p-Toluenesulfonic acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Methanesulfonic acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd. Ethanesulfonic acid: manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.

〔others〕
<Surfactant>
・CRODAFOS KD-66: Alkyl phosphate ester, manufactured by Croda ・Polyoxyethylene alkyl phosphate ester: manufactured by Nikko Chemicals, product name "NIKKOL DDP-8"
<Organic solvent>
Methanol: FUJIFILM Wako Pure Chemical Industries, Ltd. Ethylene glycol: FUJIFILM Wako Pure Chemical Industries, Ltd. Acetonitrile: FUJIFILM Wako Pure Chemical Industries, Ltd. <Preservatives>
・Propionic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Benzoic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Sorbic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Salicylic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. <Corrosion inhibitor>
Pyrocatechol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Pyrogallol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Gallic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Imidazole: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Pyrazole: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 2,4-Dimethylthiazole: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 1,2,4-Triazole: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 1H-Tetrazole (1,2,3,4-Tetrazole): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 3-Amino-5-methylpyrazole: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Adenine: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.・Pyridine: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Pyrazine: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Pyrimidine: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Hydroxylamine: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Chlorhexidine gluconate: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Ascorbic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Thioglycolic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Dithiodiglycolic acid: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Polyethylene glycol: FUJIFILM Wako Pure Chemical Industries, Ltd. ・Cyclodextrin: FUJIFILM Wako Pure Chemical Industries, Ltd. <pH preparations>
TMAH: Tetramethylammonium hydroxide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. TEAH: Tetraethylammonium hydroxide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Choline: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Sulfuric acid: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[pH adjuster and water]
In the manufacturing process of the cleaning solution in this example, sulfuric acid ( _H2SO4 ) and _ultrapure water were used as a pH adjuster. The content of the pH adjuster (sulfuric acid) was 2 mass% or less with respect to the total mass of the cleaning solution in both the cleaning solutions of the example and the comparative example.

[Preparation of cleaning solution]
A method for producing the cleaning solution of the first embodiment will be described.
Isopropanolamine, serine, and polyacrylic acid (Mw=10,000) were added to ultrapure water according to the table below, and then sulfuric acid was added as a pH adjuster so that the pH of the prepared cleaning solution was 3.0. The resulting mixture was thoroughly stirred to obtain the cleaning solution of Example 1.

The cleaning solutions of each of the examples and comparative examples were produced using the same manufacturing method as in Example 1, except that each component was adjusted according to the table below.

[Cleaning performance]
The cleaning performance (residue removal performance) was evaluated when the cleaning solution of each Example or Comparative Example was used to clean a metal film after CMP treatment.
Using a FREX-300SII (polishing device, manufactured by Ebara Corporation), a wafer (diameter ¹² inches) having a metal film made of tungsten on its surface was subjected to CMP using a polishing liquid (W2000, manufactured by Cabot Corporation) under conditions of a polishing liquid supply rate of 0.28 ml/(min·cm 2 ), a polishing pressure of 2.0 psi, and a polishing time of 60 seconds.
Thereafter, the temperature of each cleaning solution was adjusted to room temperature (23°C), and each cleaning solution was used to scrub and clean the wafer for 60 seconds, followed by drying. The number of defects on the polished surface of the obtained wafer was detected using a defect detection device, and each defect was observed with a SEM (scanning electron microscope) to classify the defects. If necessary, the constituent elements were analyzed with an EDAX (energy dispersive X-ray analyzer) to identify the components. This allowed the number of defects based on the residue to be determined, and the cleaning performance was evaluated according to the following evaluation criteria (evaluation 6 being the most excellent cleaning performance).
(Evaluation criteria)
6: The number of target defects is less than 20. 5: The number of target defects is 20 or more but less than 50. 4: The number of target defects is 50 or more but less than 100. 3: The number of target defects is 100 or more but less than 200. 2: The number of target defects is 200 or more but less than 300. 1: The number of target defects is 300 or more.

[Corrosion inhibition performance]
The cleaning solutions of the Examples and Comparative Examples were used to evaluate the corrosion inhibition performance when cleaning a metal film.
A wafer (diameter 12 inches) having a metal film made of tungsten on its surface was cut to prepare a 2 cm square wafer coupon. The thickness of each metal film was 200 nm. The wafer was immersed in each cleaning solution, and the thickness of the metal film that disappeared was determined 30 minutes after immersion in each cleaning solution for the metal film made of tungsten at room temperature (23° C.) and agitation speed of 250 rpm. The corrosion rate of the metal film per unit time was calculated from the thickness of the disappeared film.
The corrosion inhibiting performance was evaluated according to the following evaluation criteria: The lower the corrosion rate, the better the corrosion inhibiting performance of the cleaning liquid (rating 6 is the best corrosion inhibiting performance).
(Evaluation criteria)
6: Corrosion rate is 0.2 Å/min or less. 5: Corrosion rate is more than 0.2 Å/min and less than 0.5 Å/min. 4: Corrosion rate is more than 0.5 Å/min and less than 1 Å/min. 3: Corrosion rate is more than 1 Å/min and less than 3 Å/min. 2: Corrosion rate is more than 3 Å/min and less than 5 Å/min. 1: Corrosion rate is more than 5 Å/min.

[result]
The following table shows the composition of the cleaning solution and the evaluation results for each of the examples and comparative examples.
In the table, the column "Mw" indicates the weight average molecular weight.
The column "Content (mass %)" indicates the content (unit: mass %) of each component relative to the total mass of the cleaning liquid.
The column "Amount of active ingredient (mass %)" indicates the content of each ingredient relative to the total mass of the cleaning solution excluding the solvent.
The column "(C)/(B)" indicates the mass ratio of the content of the specific complexing agent to the content of the alkanolamine [content of specific complexing agent/content of alkanolamine].
The column "(C)/(A)" indicates the mass ratio of the content of the specific complexing agent to the content of the polymer [content of specific complexing agent/content of polymer].
The values in the "pH" column indicate the pH of the cleaning solution at 25°C measured using the pH meter described above.
A "*1" in the "pH" column means that, if necessary, H ₂ SO ₄ (sulfuric acid) was added in an amount such that the pH of the prepared cleaning solution would be the value in the "pH" column.
The "balance" in the "Water" column means that the balance of the cleaning solution other than each component is water.

As shown in the table, it was confirmed that the cleaning solution of the present invention provides the desired effects.
From a comparison between Examples 1 and 60 to 63 and Examples 64 to 66, it was confirmed that when the weight average molecular weight of the polymer was 2,000 to 500,000, the effect was more excellent.
From a comparison of Examples 1, and 17 to 21 with Examples 22 and 23, it was confirmed that the effect was more excellent when the mass ratio [(C)/(B)] of the content of the specific complexing agent to the content of the alkanolamine was 0.1 to 1000.0. It was also confirmed that the effect was even more excellent when [(C)/(B)] was 0.1 to 400.0.
From a comparison of similar examples, it was confirmed that the effect was more excellent when the content of the complexing agent was 3.0 to 10.0 mass% relative to the total mass of the cleaning solution, and that the effect was even more excellent when the content of the complexing agent was 3.0 to 4.0 mass% relative to the total mass of the cleaning solution.
From a comparison of Examples 1, 53 to 55, 67, and 69 with Examples 56 and 68, it was confirmed that the effect is more excellent when the mass ratio [(C)/(A)] of the content of the specific complexing agent to the content of the polymer is 1.5 to 50.0.
From a comparison between Example 1 and Examples 41 to 44, it was confirmed that the effect is more excellent when the specific complexing agent contains at least one selected from the group consisting of the compound represented by formula (B1), the compound represented by formula (B3), the compound represented by formula (B4), the compound represented by formula (C), diphosphate, hexametaphosphate, phytic acid, and the compound represented by formula (P1).
From a comparison of Examples 29 to 30 with Example 1 and the like, it was confirmed that the cleaning effect was superior when the cleaning liquid further contained a surfactant.
Comparison with Examples 83 to 102 and 106 to 107 confirmed that the cleaning effect was superior when the cleaning solution further contained an anticorrosive agent.

In the above-mentioned cleaning performance evaluation test, a CMP process was carried out on a wafer having metal wiring made of tungsten on its surface, and then the polished surface of the wafer was subjected to a buff polishing process.
In the buffing process, each cleaning solution adjusted to room temperature (23° C.) was used as the buffing composition. The buffing process was performed using the polishing apparatus used in the CMP process under the following conditions: polishing pressure: 2.0 psi, supply rate of the buffing composition: 0.28 mL/(min·cm ² ), and polishing time: 60 seconds.
Thereafter, the buffed wafer was cleaned for 30 seconds using a sample of each diluted cleaning solution adjusted to room temperature (23° C.), and then dried.
The cleaning performance of the cleaning liquid was evaluated for the polished surface of the obtained wafer according to the evaluation test method described above in [Evaluation of cleaning performance], and it was confirmed that the evaluation results were similar to those of the cleaning liquids of the above examples.

Claims (21)

A semiconductor substrate cleaning solution used for cleaning a semiconductor substrate, comprising:
The composition includes a polymer, an alkanolamine, a complexing agent having an acid group, and water,
The weight average molecular weight of the polymer is 2,000 to 900,000;
the content of the complexing agent is 2.5 mass % or more and less than 20.0 mass % with respect to the total mass of the cleaning solution for semiconductor substrates,
The pH of the cleaning liquid for semiconductor substrates is less than 7.0,
A cleaning solution for semiconductor substrates , wherein a mass ratio of a content of the complexing agent to a content of the alkanolamine is 0.1 to 1000.0. A semiconductor substrate cleaning solution used for cleaning a semiconductor substrate, comprising:
The composition includes a polymer, an alkanolamine, a complexing agent having an acid group, and water,
The weight average molecular weight of the polymer is 2,000 to 900,000;
the content of the complexing agent is 2.5 mass % or more and less than 20.0 mass % with respect to the total mass of the cleaning solution for semiconductor substrates,
The pH of the cleaning liquid for semiconductor substrates is less than 7.0,
The polymer comprises polyacrylic acid, polymaleic acid, a copolymer of styrene and a monomer of (meth)acrylic acid and/or maleic acid, a copolymer of (meth)acrylic acid and maleic acid, or a salt thereof. 3. The cleaning solution for semiconductor substrates according to claim 2 , wherein a mass ratio of a content of said complexing agent to a content of said alkanolamine is 0.1 to 1000.0. 4. The cleaning solution for a semiconductor substrate according to claim 1 , wherein the complexing agent has at least one selected from the group consisting of a carboxyl group, a phosphoric acid group, a phosphonic acid group, and a sulfonic acid group. 5. The cleaning solution for semiconductor substrates according to claim 1, wherein the complexing agent does not include a complexing agent having a phosphonic acid having two or more nitrogen atoms. 6. The cleaning solution for a semiconductor substrate according to claim 1, wherein the complexing agent comprises at least one selected from the group consisting of a complexing agent having a carboxy group, a complexing agent having a phosphoric acid group, a complexing agent having a sulfonic acid group, and a complexing agent having a phosphonic acid group represented by formula (P1):
In formula (P1), X represents a hydrogen atom or a hydroxyl group.
R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 7. The cleaning solution for semiconductor substrates according to claim 6, wherein the complexing agent having a phosphate group is polyphosphoric acid or phytic acid. The cleaning solution for a semiconductor substrate according to any one of claims 1 to 7 , wherein the weight average molecular weight of the polymer is 2,000 to 500,000. 9. The cleaning solution for semiconductor substrates according to claim 1 , wherein the alkanolamine has a pKa of 7.50 to 15.00. 10. The cleaning solution for a semiconductor substrate according to claim 1 , wherein the alkanolamine comprises at least one selected from the group consisting of monoethanolamine, isopropanolamine, and trishydroxymethylaminomethane. 11. The cleaning solution for semiconductor substrates according to claim 1, wherein the content of said alkanolamine is 0.01 to 7.0 mass % based on the total mass of said cleaning solution for semiconductor substrates. 12. The cleaning solution for a semiconductor substrate according to claim 1, wherein a mass ratio of a content of said complexing agent to a content of said polymer is from 1.0 to 100.0. 13. The cleaning solution for semiconductor substrates according to claim 1, wherein the content of said complexing agent is 3.0 to 10.0 mass % based on the total mass of said cleaning solution for semiconductor substrates. The cleaning solution for semiconductor substrates according to any one of claims 1 to 13 , wherein the content of said complexing agent is 3.0 to 4.0 mass % based on the total mass of said cleaning solution for semiconductor substrates. The cleaning solution for semiconductor substrates according to any one of claims 1 to 14 , further comprising an anticorrosive agent. The cleaning solution for semiconductor substrates according to any one of claims 1 to 15 , further comprising a surfactant. The cleaning solution for a semiconductor substrate according to claim 16 , wherein the surfactant comprises an anionic surfactant. The cleaning solution for a semiconductor substrate according to claim 16 or 17 , wherein the surfactant comprises at least one selected from the group consisting of an alkyl phosphate ester and a polyoxyethylene alkyl phosphate ester. The cleaning solution for a semiconductor substrate according to any one of claims 1 to 18 , further comprising a hydrophilic organic solvent. The semiconductor substrate cleaning solution according to any one of claims 1 to 19 , wherein the semiconductor substrate has a metal film containing tungsten. The cleaning solution for semiconductor substrates according to any one of claims 1 to 20 , which is used as a cleaning solution to be applied to a semiconductor substrate that has been subjected to a chemical mechanical polishing process.