Cleaning liquid, method for cleaning semiconductor substrate, method for manufacturing semiconductor device

Abstract

The present invention addresses the problem of providing a cleaning liquid which exhibits excellent ceria particle removability after a CMP treatment using ceria particles, while suppressing dissolution of a substrate. A cleaning liquid according to the present invention is used for a semiconductor substrate that has been subjected to a chemical mechanical polishing treatment, and contains a nonionic surfactant and at least one reducing agent selected from the group consisting of a reducing agent having two or more hydroxyl groups and a reducing agent containing a disulfide bond or a thiol group and a carboxyl group. The cleaning liquid has a pH of 1.8 to 6.0. The content of a fluorine-containing compound is less than 0.1 mass% with respect to the total mass of the cleaning liquid, and the content of the nonionic surfactant is 0.3–20 mass% with respect to the total mass of the cleaning liquid, or the mass ratio of the content of the nonionic surfactant to the content of the reducing agent is 1.00–100.00.

Description

Cleaning liquid, method for cleaning a semiconductor substrate, method for manufacturing a semiconductor device

[0001] The present invention relates to a cleaning liquid, a method for cleaning a semiconductor substrate, and a method for manufacturing a semiconductor device.

[0002] In the semiconductor field, with the remarkable increase in integration density and performance, even extremely small amounts of impurities (contamination) and / or deposits (particles) have come to have a great impact on the performance of the device and, consequently, the yield of the product. In each manufacturing process of semiconductor elements, various contaminations and particles (hereinafter also referred to as residues) can occur. When manufacturing a semiconductor, a substrate processing step is appropriately carried out to remove such residues.

[0003] For example, in the manufacture of semiconductor elements, a chemical mechanical polishing (CMP: Chemical Mechanical Polishing) process may be carried out to flatten the surface of a semiconductor substrate having a metal wiring film, a barrier metal, and an insulating film, etc., using a polishing slurry containing polishing particles (e.g., silica, alumina, and ceria, etc.). In the CMP process, metal components derived from the polishing particles used in the CMP process, the polished wiring metal film and / or barrier metal, etc., tend to remain on the surface of the semiconductor substrate after polishing and the members used for polishing (e.g., a polishing pad). Therefore, after the CMP process, a step of removing these residue substances using a cleaning liquid is generally carried out.

[0004] As such a cleaning liquid, for example, Patent Document 1 discloses a surface treatment composition containing a nitrogen-free nonionic polymer, a nitrogen-containing nonionic polymer, and an anionic polymer, wherein the content ratio of each polymer is within a predetermined range and the pH is less than 7.0.

[0005] Japanese Unexamined Patent Application Publication No. 2023 - 148443

[0006] In chemical mechanical polishing, ceria particles (cerium oxide particles) may be used as polishing particles. When the present inventors applied the above chemical solution to a substrate after CMP treatment using ceria particles, they found that there is room for improvement in the removability of ceria particles. Also, the above cleaning solution is required not to dissolve the substrate to be cleaned.

[0007] Therefore, an object of the present invention is to provide a cleaning solution that is excellent in the removability of ceria particles after CMP treatment using ceria particles and suppresses dissolution of the substrate. Another object of the present invention is to provide a method for cleaning a semiconductor substrate and a method for manufacturing a semiconductor device using the above cleaning solution.

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0009] [1] A cleaning solution for use on a semiconductor substrate that has undergone chemical mechanical polishing, comprising a nonionic surfactant, a reducing agent having two or more hydroxyl groups, and at least one reducing agent selected from the group consisting of a disulfide bond or a thiol group and a carboxyl group, wherein the content of the nonionic surfactant is 0.3 to 20% by mass of the total mass of the cleaning solution, the pH is 1.8 or higher and 6.0 or lower, and the content of a fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution. [2] A cleaning solution for use on a semiconductor substrate that has undergone chemical mechanical polishing, comprising a nonionic surfactant, a reducing agent having two or more hydroxyl groups, and at least one reducing agent selected from the group consisting of a disulfide bond or a thiol group and a carboxyl group, wherein the mass ratio of the content of the nonionic surfactant to the content of the reducing agent is 1.00 to 100.00, the pH is 1.8 or more and 6.0 or less, and the content of a fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution. [3] The cleaning solution according to [1] or [2], wherein the reducing agent having two or more hydroxyl groups comprises at least one selected from the group consisting of ascorbic acid compounds, polyphenol compounds, hydrogen peroxide, and sugars. [4] The cleaning solution according to any one of [1] to [3], wherein the nonionic surfactant is a polyether-based surfactant. [5] A cleaning solution according to any one of [1] to [4], further comprising an inorganic acid. [6] A cleaning solution according to [5], wherein the mass ratio of the content of the nonionic surfactant to the content of the inorganic acid is greater than 1. [7] A cleaning solution according to any one of [1] to [6], further comprising a chelating agent. [8] A cleaning solution according to any one of [1] to [7], wherein the semiconductor substrate comprises a silicon oxide-based insulating film. [9] A cleaning solution according to any one of [1] to [8], wherein the chemical mechanical polishing treatment is a treatment using ceria particles.

[10] A method for cleaning a semiconductor substrate, comprising the step of cleaning a semiconductor substrate that has undergone chemical mechanical polishing treatment using a cleaning solution according to any one of [1] to [9].

[11] A method for manufacturing a semiconductor device, comprising the method for cleaning a semiconductor substrate according to

[10] .

[0010] According to the present invention, a cleaning solution can be provided that exhibits excellent removal of ceria particles after CMP treatment using ceria particles, and suppresses the dissolution of the substrate. Furthermore, according to the present invention, a method for cleaning a semiconductor substrate and a method for manufacturing a semiconductor device related to the above-mentioned cleaning solution can also be provided.

[0011] The present invention will be described in detail below. The following descriptions of constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0012] In this specification, a numerical range expressed using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits. Also in this specification, if there are two or more types of a component, the "content" of that component means the total content of those two or more types of components. In this specification, in numerical ranges described in steps, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in steps. Also, in numerical ranges described in this specification, the upper or lower limit stated in one numerical range may be replaced with the value shown in the example. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0013] In this specification, "total mass of components in the cleaning solution excluding the solvent" means the total mass of all components contained in the cleaning solution other than the solvent, such as water and organic solvents.

[0014] In this specification, "ppm" means "parts-per-million (10) －６ ) means "ppb" means "parts-per-billion (10 －９ ) means "ppt" is "parts-per-trillion (10 －１２ This means ) ). In this specification, 1 Å (angstrom) corresponds to 0.1 nm.

[0015] In this specification, weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity (hereinafter also referred to as "molecular weight distribution") (Mw / Mn) are defined as polystyrene-converted values ​​obtained by GPC (Gel Permeation Chromatography) measurement using a GPC (Gel Permeation Chromatography) instrument (HLC-8120GPC, manufactured by Tosoh Corporation) (solvent: tetrahydrofuran, flow rate (sample injection volume): 10 μL, column: TSK gel Multipore HXL-M (manufactured by Tosoh Corporation), column temperature: 40°C, flow rate: 1.0 mL / min, detector: differential refractive index detector (Refractitive Index Detector)).

[0016] Unless otherwise specified, the compounds described herein may include structural isomers, optical isomers, and isotopes. Furthermore, structural isomers, optical isomers, and isotopes may be present individually or in combination of two or more. Unless otherwise specified, the components of the washing solutions described herein may be ionized in the washing solution and may form salts.

[0017] The cleaning solution of the present invention will be described in detail below. The cleaning solution of the first embodiment of the present invention (hereinafter also simply referred to as the "first cleaning solution") is a cleaning solution used for a semiconductor substrate that has been subjected to chemical mechanical polishing, and comprises a nonionic surfactant, a reducing agent having two or more hydroxyl groups, and at least one reducing agent selected from the group consisting of a disulfide bond or a thiol group and a carboxyl group, wherein the content of the nonionic surfactant is 0.3 to 20% by mass of the total mass of the cleaning solution, the pH is 1.8 or higher and 6.0 or lower, and the content of the fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution. A cleaning solution according to a second aspect of the present invention (hereinafter also simply referred to as the "second cleaning solution") is a cleaning solution used for a semiconductor substrate that has undergone chemical mechanical polishing, and comprises a nonionic surfactant and at least one reducing agent selected from the group consisting of a reducing agent having two or more hydroxyl groups and a reducing agent containing a disulfide bond or a thiol group and a carboxyl group, wherein the mass ratio of the content of the nonionic surfactant to the content of the reducing agent is 1.00 to 100.00, the pH is 1.8 or higher and 6.0 or lower, and the content of a fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution. In this specification, when simply referred to as the "cleaning solution of the present invention" or "cleaning solution," the concept includes both the first cleaning solution and the second cleaning solution.

[0018] The reason why a cleaning solution having the above configuration can solve the problems of the present invention is not necessarily clear, but the inventors speculate as follows. Note that the following speculation does not limit the mechanism by which the effect is obtained. In other words, even if the effect is obtained by a mechanism other than those described below, it is still within the scope of the present invention. It is stated in "Surface Science Vol. 33, No. 6, pp. 351-356, 2012" that ceria particles form chemical bonds on the substrate surface, and these chemical bonds are dissociated by electron transfer. Here, the reducing agent contained in the cleaning solution of the present invention exhibits high reducing ability under conditions where the pH is 1.8 or higher due to the presence of a predetermined functional group. It is speculated that the presence of such a reducing agent under acidic conditions where the pH is 6.0 or lower releases the chemical bond between the ceria particles and the substrate surface, making it easier to remove the ceria particles from the substrate. Furthermore, since the first cleaning solution contains a predetermined amount of nonionic surfactant, it does not cause a decrease in the removal efficiency of ceria particles due to an excess amount of nonionic surfactant, and effectively suppresses the re-adhesion of ceria particles. Furthermore, in the second cleaning solution, the mass ratio of the nonionic surfactant to the reducing agent is within a predetermined range, so both the effects of the nonionic surfactant and the reducing agent function appropriately. In addition, while fluorine-containing compounds can remove ceria particles along with the substrate surface, they tend to have a high etching effect on the substrate. In the cleaning solution of the present invention, by suppressing the dissolution of the substrate by keeping the content of the fluorine-containing compound below a predetermined amount, while satisfying the above requirements, excellent ceria particle removal performance can be achieved. Hereinafter, the superior removal of ceria particles after CMP treatment using ceria particles will simply be referred to as "the effects of the present invention are superior."

[0019] [First Cleaning Solution] The first cleaning solution will be described in detail below.

[0020] [Nonionic Surfactants] The first washing solution contains a nonionic surfactant. Nonionic surfactants typically have a hydrophilic part and a hydrophobic part and do not have an ionic group. An ionic group is a group that can dissociate into anions and cations in water, at least in part. Examples of ionic groups include acidic groups such as carboxylic acid groups, sulfonic acid groups, and phosphate groups or their salts, as well as ammonium bases.

[0021] Examples of the hydrophobic portion of a nonionic surfactant include hydrocarbon groups which may have substituents. Examples of hydrocarbon groups include aliphatic hydrocarbon groups and aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear, branched, or cyclic. The aromatic hydrocarbon group may be monocyclic or polycyclic. The number of carbon atoms in the hydrocarbon group is preferably 6 or more, more preferably 10 or more, even more preferably 12 or more, and particularly preferably 15 or more. There is no particular upper limit, but from the viewpoint of solubility, it is preferably 30 or less, and more preferably 24 or less. Examples of substituents which the hydrocarbon group may have include alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, and halogen atoms. The hydrophobic portion is preferably an aliphatic hydrocarbon group or an aryl group which may have a substituent, and more preferably an alkyl group, an alkenyl group, or an aryl group which may have an aralkyl group or alkyl group.

[0022] As a nonionic surfactant, a polyether-based surfactant is preferred. As the polyether structure of the polyether-based surfactant, a polyoxyalkylene structure is preferred. The polyoxyalkylene structure is -(O-AL) ｎ The structure is represented by -, where AL represents an alkylene group and n represents an integer of 2 or more. The number of carbon atoms in the alkylene group represented by AL is preferably 1 to 6, more preferably 2 or 3. n is preferably an integer from 2 to 50, more preferably an integer from 4 to 30, and even more preferably an integer from 6 to 20. In the polyoxyalkylene structure, the multiple alkylene groups (the groups represented by AL above) may be the same or different from each other. Among nonionic surfactants, it is preferable that the polyether structure includes at least one selected from the group consisting of a polyoxyethylene structure and a polyoxypropylene structure.

[0023] As polyether surfactants, for example, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, compounds represented by R １１ -(O-AL) ｎ -OH, polyoxyalkylene alkyl esters, fatty acid esters having a polyoxyalkylene structure, fatty acid amides having a polyoxyalkylene structure, polyoxyalkylene castor oil-based compounds, polyoxyethylene alkylamines, acetylene glycols, polyoxyalkylene phytosterols, and copolymers of polyethylene glycol and polypropylene glycol, etc. may be mentioned. In the compound represented by R １１ -(O-AL) ｎ -OH, R １１ represents a hydrocarbon group which may have a substituent, and examples and preferred embodiments are the same as the groups exemplified as the hydrophobic part of the nonionic surfactants described above. AL and n are as described above. As the compound represented by R １１ -(O-AL) ｎ -OH, polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenyl ethers, polyoxyalkylene distyrenated phenyl ethers, and polyoxyethylene polystyryl phenyl ethers, etc. may be mentioned. The above fatty acid ester is an ester of a fatty acid and an alcohol. When the alcohol is a polyhydric alcohol, it may be a partially esterified fatty acid partial ester. As the fatty acid ester having a polyoxyalkylene structure, polyoxyalkylene glycerin fatty acid esters, polyoxyalkylene glycol fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, polyoxyalkylene pentaerythritol fatty acid esters, polyoxyalkylene sucrose fatty acid esters, and polyoxyalkylene triethanolamine fatty acid esters, etc. may be mentioned. As the above fatty acid amide having a polyoxyalkylene structure, compounds obtained by substituting the ester bond in the above fatty acid ester with an amide bond may be mentioned. As polyether surfactants, polyalkylene glycols, R １１ -(O-AL)ｎ Compounds represented by -OH or fatty acid esters having a polyoxyalkylene structure are preferred, polyoxyalkylene alkyl ethers, polyoxyalkylene alkylaryl ethers, polyoxyalkylenedistyrene phenyl ethers, or fatty acid esters having a polyoxyalkylene structure are more preferred, and polyoxyethylene distyleninated phenyl ethers or polyoxyalkylene sorbitan fatty acid esters are even more preferred.

[0024] Examples of polyoxyalkylene sorbitan fatty acid esters include compounds represented by formula (1).

[0025]

[0026] In formula (1), w, x, y, and z each independently represent an integer of 2 or more, preferably an integer between 2 and 50, more preferably an integer between 4 and 30, and even more preferably an integer between 6 and 20. w + x + y + z is an integer selected from 8 to 60. w + x + y + z is more preferably an integer between 8 and 30, and even more preferably an integer between 8 and 20, in terms of superior effects of the present invention. In formula (1), R １ ~R ４ Each of these is independently a hydrogen atom, or -CO-R ５ Represents R ５ R represents an aliphatic hydrocarbon group with 6 or more carbon atoms. １ ~R ４ At least one of them is -CO-R ５ Represents R １ ~R ４ One to three of them are -CO-R ５ It is preferable to represent -CO-R ５ It is more preferable to represent this. Also, at least R １ ga-CO-R ５ It is preferable to represent R. ５The aliphatic hydrocarbon group represented above has 6 or more carbon atoms, preferably 6 to 24, more preferably 8 to 20, and even more preferably 12 to 18. The aliphatic hydrocarbon group is preferably an alkyl group or an alkenyl group. The aliphatic hydrocarbon group may be linear, branched, or cyclic, with linear being preferred.

[0027] Examples of polyoxyalkylene sorbitan fatty acid esters include polyoxyethylene sorbitan monofatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan monooleate, as well as polyoxyethylene sorbitan trifatty acid esters such as polyoxyethylene sorbitan tristearate and polyoxyethylene sorbitan trioleate, with polyoxyethylene sorbitan monofatty acid esters being preferred.

[0028] Among the polyoxyalkylene sorbitan fatty acid esters, Tween 20 (polysorbate 20), Tween 40 (polysorbate 40), Tween 60 (polysorbate 60), Tween 65 (polysorbate 65), or Tween 80 (polysorbate 80) are preferred, with Tween 80 (polysorbate 80) being more preferred.

[0029] Examples of nonionic surfactants other than the polyether-based surfactants mentioned above include fatty acid esters without a polyoxyethylene structure, fatty acid amides, fatty acid diethanolamides, N,N-bis-2-hydroxyalkylamines, and trialkylamine oxides. Examples of fatty acid esters without a polyoxyethylene structure include glycerin fatty acid esters, polyglycerin fatty acid esters, glycol fatty acid esters, sorbitan fatty acid esters, sorbitol fatty acid esters, pentaerythritol fatty acid esters, sucrose fatty acid esters, and triethanolamine fatty acid esters. The fatty acid esters may also be partial fatty acid esters in which a portion has been esterified.

[0030] The HLB (Hydrophile-Lipophile Balance) value of a nonionic surfactant is preferably 12 or higher, more preferably 14 or higher, and even more preferably 15 or higher. There is no particular upper limit, but it is usually 20 or lower. The above HLB value is defined by the value calculated using the Griffin formula (20 × Mw / M; Mw = molecular weight of the hydrophilic portion, M = molecular weight of the nonionic surfactant), and in some cases, catalog values ​​or values ​​calculated by other methods may be used. An HLB value closer to 20 means that it is hydrophilic, and an HLB value closer to 0 means that it is lipophilic.

[0031] When a nonionic surfactant has a hydrophobic portion, the value of the number of carbon atoms / HLB of the hydrophobic portion is preferably 0.60 or higher, more preferably 0.90 or higher, and even more preferably 1.00 or higher. There is no particular upper limit to the number of carbon atoms / HLB of the hydrophobic portion, but it is often 1.50 or lower, and preferably 1.30 or lower. For example, if the nonionic surfactant has a hydrocarbon group which may have substituents as the hydrophobic portion, the number of carbon atoms of the hydrocarbon group which may have substituents corresponds to the number of carbon atoms of the hydrophobic portion. The molecular weight of the nonionic surfactant is preferably 1000 or higher, more preferably 1300 or higher. There is no particular upper limit, but it is preferably 7000 or lower, more preferably 5000 or lower, and even more preferably 4000 or lower. When the nonionic surfactant has a molecular weight distribution, it is preferable that the weight-average molecular weight satisfies the above range. In particular, when the nonionic surfactant has a hydrophobic portion, it is preferable that the HLB value is 15 or higher, and the value of the number of carbon atoms in the hydrophobic portion / HLB value is 1.00 or higher.

[0032] Examples of nonionic surfactants include high molecular weight nonionic surfactants. Examples of high molecular weight nonionic surfactants include polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylamide, and copolymers thereof. The weight-average molecular weight of high molecular weight nonionic surfactants is not particularly limited, but is typically between 2,000 and 2,000,000, preferably between 3,000 and 1,500,000, and more preferably between 3,000 and 100,000. In particular, high molecular weight nonionic surfactants preferably have an HLB value of 15 or higher, and more preferably 18 or higher.

[0033] Nonionic surfactants may be used alone or in combination of two or more. The content of nonionic surfactants is 0.3 to 20% by mass of the total mass of the first cleaning solution, and is preferably 0.4 to 10% by mass, more preferably 0.6 to 5% by mass, and even more preferably 0.8 to 3% by mass, in terms of achieving superior effects of the present invention.

[0034] [Reducing Agent] The first washing solution contains at least one reducing agent selected from the group consisting of a reducing agent having two or more hydroxyl groups (hereinafter also referred to as "reducing agent O") and a reducing agent containing a disulfide bond or a thiol group and a carboxyl group (hereinafter also referred to as "reducing agent S") (hereinafter also referred to as "reducing agent"). Note that the above reducing agent is a different compound from the nonionic surfactant described above.

[0035] The reducing agent O may contain two or more hydroxyl groups, or even three or more. There is no particular upper limit, but it is often six or less. Examples of reducing agent O include compounds having an enediol structure, polyphenol compounds, hydrogen peroxide, and sugars.

[0036] <Compounds containing an enediol structure> An enediol structure is a structure represented as -C(OH)=C(OH)-. This structure exhibits reducing activity when oxidized to a diketone structure (-C(=O)-C(=O)-). Examples of compounds containing an enediol structure include ascorbic acid compounds.

[0037] Examples of ascorbic acid compounds include ascorbic acid and its derivatives, as well as salts thereof. Examples of ascorbic acid include L-ascorbic acid, D-ascorbic acid, and isoascorbic acid. Examples of ascorbic acid derivatives include compounds obtained by converting (e.g., etherification and esterification) the hydroxyl groups that do not constitute the enediol structure of ascorbic acid. Examples of ascorbic acid derivative compounds include those described in paragraphs

[0026] to

[0039] of International Publication No. 2019 / 138706, and these contents are incorporated herein by reference. Examples of salts of ascorbic acid and ascorbic acid derivatives include alkali metal salts such as sodium ascorbate. Ascorbic acid compounds are preferably ascorbic acid or salts thereof.

[0038] <Polyphenol Compounds> Polyphenol compounds are compounds having at least two phenolic hydroxyl groups. The number of phenolic hydroxyl groups in a polyphenol compound is two or more, preferably three or more. There is no particular upper limit, but it is often six or less, and preferably four or less. Examples of polyphenol compounds include catechol, resorcinol, hydroquinone, and their derivatives.

[0039] As the polyphenol compound, the compound represented by formula (A) is preferred.

[0040]

[0041] R Ａ R represents a hydrogen atom or a monovalent organic group. Ａ These may be the same or different. There are no particular limitations on the monovalent organic group, but examples include carboxyl groups, aldehyde groups, and hydrocarbon groups that may have heteroatoms. Examples of hydrocarbon groups having heteroatoms include -O-, -CO-, -COO-, and -NR between carbon-carbon bonds or at the terminals. Ｎ -, -CONR Ｎ -, -S-, and -SO ２ Examples include hydrocarbon groups having at least one divalent linking group selected from the group consisting of -. Ｎrepresents a hydrogen atom or an alkyl group. The number of carbon atoms in the hydrocarbon group is preferably 1 to 25, more preferably 1 to 15, and even more preferably 1 to 10. The hydrocarbon group may be linear, branched, or cyclic. If the hydrocarbon group has a ring structure, the ring may be monocyclic or polycyclic. The hydrocarbon group may further have substituents. Examples of substituents that the hydrocarbon group may further have include halogen atoms such as chlorine atoms, hydroxyl groups, alkoxy groups, acyl groups, alkyl groups, amino groups, carboxyl groups, thiol groups, cyano groups, and nitro groups, with hydroxyl groups, alkoxy groups having 1 to 4 carbon atoms, alkyl groups having 1 to 4 carbon atoms, amino groups, or carboxyl groups being preferred, and hydroxyl groups, amino groups, or carboxyl groups being more preferred. As the hydrocarbon group, alkyl groups, alkenyl groups, or aryl groups are preferred. Ａ Preferably, the group is a hydrogen atom, a carboxyl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, an acyl group, an alkoxy group, an alkyloxycarbonyl group, or a heteroaryl group; more preferably, a hydrogen atom, an optionally substituted alkyl group, an alkoxy group, or a carboxyl group; and even more preferably, a hydrogen atom, a methyl group, a methoxy group, an aminoethyl group, or a carboxyl group.

[0042] Multiple R Ａ They may be joined to each other to form a ring. Ａ The ring formed by the bonding of these groups may further have substituents. Examples of substituents include substituents that the hydrocarbon group may have, with hydroxyl groups or carboxyl groups being preferred. Multiple R Ａ Examples of ring structures formed by the bonding of these elements include a benzene skeleton, a naphthalene skeleton, a cyclohexanedione skeleton, and an anthracene skeleton.

[0043] k is an integer between 2 and 4, with 2 or 3 being preferred.

[0044] Examples of polyphenol compounds include catechol, hydroquinone, resorcinol, pyrogallol, hydroxyquinol, phloroglucinol, gallic acid, alkyl gallate, gallic acid amide, 4-tert-butylcatechol, 3-methylcatechol, catechol-4-acetic acid, urushiol, caffeic acid, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, naphthresorcinol, alizarin, endocrocin, emodin, quercetin, catechin, anthocyanin, chlorogenic acid, rosmarinic acid, curcumin, procyazinin, theaflavin, and dopamine or its salts, with catechol, pyrogallol, gallic acid, dopamine, or dopamine hydrochloride being preferred. Flavonoids such as flavonols, anthocyanidins, and flavanols can also be used as polyphenol compounds.

[0045] <Sugars> Sugars may be monosaccharides, disaccharides, trisaccharides, or polysaccharides, or mixtures thereof. Known reducing sugars can be used as sugars, such as glucose, fructose, galactose, mannose, lactose, maltose, ribose, and sorbose.

[0046] The reducing agent O preferably contains at least one selected from the group consisting of ascorbic acid compounds, polyphenol compounds, hydrogen peroxide, and sugars, more preferably contains ascorbic acid or a salt thereof, catechol, pyrogallol, gallic acid, dopamine, or dopamine hydrochloride, and even more preferably contains ascorbic acid or a salt thereof.

[0047] The reducing agent S has a disulfide bond or a thiol group, and preferably has a disulfide bond. The total number of disulfide bonds and thiol groups in the reducing agent S is 1 or more, and may be 2 or more. The number of carboxyl groups in the reducing agent S is 1 or more, and preferably 2 or more. The reducing agent S may also have functional groups other than disulfide bonds, thiol groups, and carboxyl groups. An example of a functional group other than a carboxyl group is an amino group. Examples of reducing agents S include dithiodiglycolic acid, thioglycolic acid, and cysteine, with dithiodiglycolic acid being preferred. The reducing agent S may also be in the form of a salt, such as an ammonium salt.

[0048] The reducing agent may be used alone or in combination of two or more types. The content of the reducing agent is preferably 0.05 to 5.0% by mass, more preferably 0.1 to 1.0% by mass, and even more preferably 0.1 to 0.5% by mass, based on the total mass of the first washing solution. In the first washing solution, the mass ratio of the content of the nonionic surfactant to the content of the reducing agent is preferably 1.00 to 100.00, more preferably 2.00 to 40.00, even more preferably 2.50 to 15.00, and particularly preferably 3.00 to 5.00.

[0049] [Fluorine-containing compounds] The content of fluorine-containing compounds in the first washing solution is less than 0.1% by mass, preferably 0.05% by mass or less, and more preferably 0.01% by mass or less, relative to the total mass of the first washing solution. The lower limit is 0% by mass, and it is also preferable that the first washing solution does not contain any fluorine-containing compounds. Examples of fluorine-containing compounds include F － HF ２ － , SiF ６ ２－ TiF ６ ２－ ZrF ６ ２－ , PF ６ － , and BF ４ － Examples of compounds containing fluorine-containing ions include hydrofluoric acid (HF) and ammonium fluoride (NH).４ F), hexafluorosilicic acid and its salt (H ２ SiF ６ Na ２ SiF ６ (etc.), fluoroboric acid and its salt (KBF ４ NH ４ BF ４ (etc.), fluoroboric acid, hexafluorotitanium acid (H ２ TiF ６ ), hexafluorozirconium acid (H ２ ZrF ６ ), hexafluorophosphate (HPF ６ ), and hexafluoroboric acid (HBF ４ ) are some examples.

[0050] [Inorganic Acid] The first washing solution preferably contains an inorganic acid. The inorganic acid preferably does not contain fluorine atoms. Examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, boric acid, phosphonic acid, and phosphoric acid. In addition, a salt of an inorganic acid may be used as the inorganic acid, as long as it becomes an inorganic acid or inorganic acid ion (inorganic anion) in the washing solution.

[0051] The inorganic acid may be used alone or in combination of two or more types. The inorganic acid content is preferably 0.001 to 3.0% by mass, more preferably 0.01 to 1.0% by mass, and even more preferably 0.01 to 0.5% by mass, relative to the total mass of the first cleaning solution. In terms of achieving superior effects of the present invention, the mass ratio of the nonionic surfactant content to the inorganic acid content in the first cleaning solution is preferably greater than 1, more preferably 5 or more, and even more preferably 10 or more. There is no particular upper limit to the mass ratio of the nonionic surfactant content to the inorganic acid content, but it is preferably 10,000 or less, more preferably 1,000 or less, and even more preferably 100 or less.

[0052] [Chelating Agent] The first washing solution preferably further contains a chelating agent in that the effects of the present invention are superior. The chelating agent is a compound having a functional group (coordinating group) that can function as a ligand. Note that the chelating agent is a compound different from the above-mentioned compounds (nonionic surfactants, reducing agents, and inorganic acids) that may be contained in the washing solution. Examples of chelating agents include organic chelating agents and inorganic chelating agents, with organic chelating agents being preferred. Examples of coordinating groups of the chelating agent include acidic groups. Examples of acidic groups include phosphonic acid groups, phosphoric acid groups, carboxylic acid groups, and sulfonic acid groups, with phosphonic acid groups or carboxylic acid groups being preferred, and phosphonic acid groups being more preferred. In other words, the washing solution preferably contains a phosphonic acid-based chelating agent. The number of coordinating groups of the chelating agent is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 4.

[0053] The chelating agent is preferably low molecular weight. Specifically, the molecular weight of the chelating agent is preferably 600 or less, more preferably 450 or less, and even more preferably 300 or less. The lower limit is preferably 50 or more, and more preferably 100 or more. The number of carbon atoms in the chelating agent is preferably 1 to 15, and more preferably 2 to 15.

[0054] Examples of phosphonic acid-based chelating agents include 1-hydroxyethylidene-1,1'-diphosphonic acid (HEDP), ethylidene diphosphonic acid, 1-hydroxypropylidene-1,1'-diphosphonic acid, 1-hydroxybutylidene-1,1'-diphosphonic acid, ethylaminobis(methylenephosphonic acid), dodecylaminobis(methylenephosphonic acid), nitrilotris(methylenephosphonic acid) (NTMP), ethylenediaminebis(methylenephosphonic acid) (EDDP), 1,3-propylenediaminebis(methylenephosphonic acid), and N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid). Examples include (EDTMP), ethylenediaminetetra(ethylenephosphonic acid), 1,3-propylenediaminetetra(methylenephosphonic acid) (PDTMP), 1,2-diaminopropanetetra(methylenephosphonic acid), 1,6-hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) (DEPP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), diethylenetriaminepenta(ethylenephosphonic acid), triethylenetetraminehexa(methylenephosphonic acid), and triethylenetetraminehexa(ethylenephosphonic acid). As phosphonic acid chelating agents, the compounds described in paragraphs

[0026] to

[0036] of International Publication No. 2018 / 020878 and the compounds ((co)polymers) described in paragraphs

[0031] to

[0046] of International Publication No. 2018 / 030006 may also be incorporated herein. Among the phosphonic acid chelating agents, HEDP, ethylidenediphosphonic acid, NTMP, EDTMP, or PBTC are preferred.

[0055] Examples of carboxylic acid-based chelating agents include aminocarboxylic acids, polycarboxylic acids, and hydroxycarboxylic acids. Examples of aminocarboxylic acids include diethylenetriaminepentaacetic acid (DTPA), butylenediaminetetraacetic acid, 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 (Cy-DTA), ethylenediaminediacetic acid, ethylenediaminedipropionic acid, 1,6-hexamethylene-diamine-N,N,N',N'-tetraacetic acid, and N,N-bi Examples of polyaminocarboxylic acids include (2-hydroxybenzyl)ethylenediamine-N,N-diacetic acid, diaminopropanetetraacetic acid, 1,4,7,10-tetraazacyclododecane-tetraacetic acid, diaminopropanoltetraacetic acid, (hydroxyethyl)ethylenediaminetriacetic acid, and glycol etherdiaminetetraacetic acid (GEDTA), as well as aminopolycarboxylic acids such as hydroxyethyliminodiacetic acid (HIDA), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and N,N-bis(2-hydroxyethyl)glycine (DHEG). Amino acids can also be considered as aminocarboxylic acids. Examples of amino acids include glycine, serine, α-alanine (2-aminopropionic acid), β-alanine (3-aminopropionic acid), L-lysine, leucine, isoleucine, ethionine, threonine, tryptophan, tyrosine, valine, histidine, histidine derivatives, asparagine, aspartic acid, glutamine, glutamic acid, L-arginine, proline, phenylalanine, compounds described in paragraphs

[0021] to

[0023] of Japanese Patent Publication No. 2016-086094, and salts thereof. As histidine derivatives, compounds described in Japanese Patent Publication No. 2015-165561 and Japanese Patent Publication No. 2015-165562, etc., can be used, and their contents are incorporated herein by reference. Examples of salts include alkali metal salts such as sodium salts and potassium salts, ammonium salts, carbonates, and acetates.

[0056] Examples of polycarboxylic acids include citric acid, malonic acid, maleic acid, succinic acid, malic acid, tartaric acid, and oxalic acid.

[0057] Examples of hydroxycarboxylic acids include gluconic acid, heptonic acid, glycolic acid, and lactic acid.

[0058] The chelating agent may be used alone or in combination of two or more types. The content of the chelating agent is preferably 0.001 to 1.0% by mass, more preferably 0.01 to 0.5% by mass, and even more preferably 0.01 to 0.1% by mass, based on the total mass of the first washing solution.

[0059] [Solvent] The first washing solution preferably contains a solvent. Examples of solvents include water and organic solvents. The first washing solution preferably contains water in that it provides superior effects of the present invention.

[0060] The type of water used can be any type that does not adversely affect the semiconductor substrate, and distilled water, deionized (DI) water, and pure water (ultrapure water) can be used. Pure water (ultrapure water) is preferred because it contains almost no impurities and has less impact on the semiconductor substrate during the manufacturing process.

[0061] Examples of organic solvents include known organic solvents such as alcohol-based solvents, glycol-based solvents, glycol ether-based solvents, and ketone-based solvents. The organic solvent is preferably miscible with water in any ratio. Examples of organic solvents include those exemplified in paragraphs

[0135] to

[0140] of International Publication No. 2022 / 044893, the contents of which are incorporated herein by reference.

[0062] The solvent may be used alone or in combination of two or more. The solvent content should be the remainder of the components that can be contained in the cleaning solution. The solvent content is preferably 60.0% by mass or more, more preferably 80.0% by mass or more, even more preferably 90.0% by mass or more, and particularly preferably 97.0% by mass or more, based on the total mass of the first cleaning solution. The upper limit is preferably 99.99% by mass or less, and more preferably 99.9% by mass or less, in terms of achieving superior effects of the present invention.

[0063] [Other Components] The first cleaning solution may contain other components not mentioned above. Examples of other components include polymers, basic compounds, corrosion inhibitors, and polyhydroxy compounds with a molecular weight of 500 or more.

[0064] <Polymers> As polymers, ionic polymers having ionic groups are preferred. Of the above polymers, water-soluble polymers are preferred. A "water-soluble polymer" means a compound in which two or more constituent units are linked linearly or in a network manner via covalent bonds, and in which the mass that dissolves in 100 g of water at 20°C is 0.1 g or more. More specifically, as water-soluble polymers, examples include anionic polymers such as poly(meth)acrylic acid, polysulfonic acid, and copolymers thereof (e.g., acrylic acid-sulfonic acid copolymers). As water-soluble polymers, poly(meth)acrylic acid, polysulfonic acid, or copolymers thereof are preferred, and poly(meth)acrylic acid or polysulfonic acid is more preferred. Note that all or part of the anionic groups of the above anionic polymer may form salts. The weight-average molecular weight (Mw) of the water-soluble polymer is preferably 1000 or more, and more preferably 2000 or more. The upper limit of the weight-average molecular weight (Mw) of the water-soluble polymer is often 1.5 million or less, preferably 1.2 million or less, and more preferably 1 million or less. The weight-average molecular weight of the water-soluble polymer is the value converted to polyethylene glycol, measured by GPC (gel permeation chromatography).

[0065] The polymer content is preferably 0.0001 to 5.0% by mass, and more preferably 0.001 to 0.1% by mass, relative to the total mass of the first washing solution.

[0066] <Basic Compounds> Basic compounds are compounds that exhibit basicity (pH greater than 7.0) in aqueous solution, and examples include basic inorganic compounds and basic organic compounds. Examples of basic inorganic compounds include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides, ammonia, and ammonia hydroxide. Examples of basic organic compounds include quaternary ammonium compounds and amine compounds. Examples of quaternary ammonium compounds include tetraalkylammonium compounds such as tetramethylammonium hydroxide (TMAH), trimethylethylammonium hydroxide (TMEAH), dimethyldiethylammonium hydroxide (DMDEAH), methyltriethylammonium hydroxide (MTEAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), and tetrabutylammonium hydroxide (TBAH), as well as tris(hydroxymethyl)aminomethane, 2-hydroxyethyltrimethylammonium hydroxide, and benzyltrimethylammonium hydroxide (BTMAH). Examples of amine compounds include 2-dimethylamino-2-methyl-1-propanol (DMAMP), trishydroxymethylaminomethane (Tris), 2-amino-2-methyl-1-propanol (AMP), monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA).

[0067] The polyhydroxy compounds having a molecular weight of 500 or more are different compounds from the above-mentioned compounds that may be contained in the washing solution. The above-mentioned polyhydroxy compounds are organic compounds having two or more (e.g., 2 to 200) alcoholic hydroxyl groups in one molecule. The molecular weight (or weight-average molecular weight if there is a molecular weight distribution) of the above-mentioned polyhydroxy compounds is 500 or more, preferably 500 to 100,000, and more preferably 500 to 3,000. As the above-mentioned polyhydroxy compounds, compounds exemplified in paragraphs

[0101] and

[0102] of International Publication No. 2022 / 014287 may also be referenced, and the contents of these are incorporated herein by reference.

[0068] [Physical Properties of the Washing Solution] <pH> The pH of the first washing solution is 6.0 or less, preferably 5.5 or less, and more preferably 5.0 or less, in terms of superior effects of the present invention. The lower limit of the pH is 1.8 or more, preferably 2.0 or more, more preferably 2.5 or more, even more preferably 3.5 or more, and particularly preferably 4.0 or more, in terms of superior effects of the present invention. When the pH is above the above lower limit, the electron-donating ability of the reducing agent and the chelating ability of the chelating agent to ceria particles are improved, and the effects of the present invention are superior. It is also preferable that the pH of the first washing solution is equal to or greater than the acid dissociation constant pKa of the reducing agent. If the first washing solution contains a chelating agent, it is also preferable that the pH of the first washing solution is equal to or greater than the acid dissociation constant pKa of the chelating agent. The pH of the washing solution can be measured using a known pH meter by a method in accordance with JIS Z8802-1984. The pH measurement temperature is 25°C. The pH of the cleaning solution can be adjusted by controlling the amount of various components contained in the solution.

[0069] <Metal Content> The content (measured as ion concentration) of metals (for example, metal elements Fe, Co, Na, Cu, Mg, Mn, Li, Al, Cr, Ni, Zn, Sn, and Ag) contained as impurities in the first cleaning solution is preferably 5 ppm by mass or less, and more preferably 1 ppm by mass or less, relative to the total mass of the first cleaning solution. In the manufacture of state-of-the-art semiconductor devices, it is expected that even higher purity cleaning solutions will be required, so it is even more preferable that the content of the above metals is lower than 1 ppm by mass, that is, on the order of ppb by mass or less, particularly preferably 100 ppb by mass or less, and most preferably less than 10 ppb by mass. A lower limit of 0 is preferred.

[0070] Methods for reducing metal content include, for example, performing purification treatments such as distillation and filtration using ion exchange resins or filters at the stage of raw material production or after production of the cleaning solution. Other methods for reducing metal content include using containers that minimize the elution of impurities, as described later, for the raw materials or the manufactured cleaning solution. Additionally, lining the inner walls of pipes with fluororesin can be applied to prevent metal components from leaching out during the production of the cleaning solution.

[0071] <Coarse Particles> The first washing solution may contain coarse particles, but it is preferable that the content be low. Coarse particles refer to particles whose diameter (particle size) is 1 μm or more when the shape of the particle is considered to be a sphere. Coarse particles contained in the washing solution include particles such as dust, dirt, organic solids, and inorganic solids that are contained as impurities in the raw materials, as well as particles such as dust, dirt, organic solids, and inorganic solids that are introduced as contaminants during the preparation of the washing solution and that ultimately remain as particles in the washing solution without dissolving.

[0072] The coarse particle content in the first washing solution is preferably 100 or less, and more preferably 50 or less, of particles with a particle size of 1 μm or larger per 1 mL of the first washing solution. The lower limit is preferably 0 or more, and more preferably 0.01 or more, per 1 mL of the first washing solution. The coarse particle content present in the washing solution can be measured in the liquid phase using a commercially available measuring device that employs a light scattering type liquid particle measurement method with a laser as the light source. As a method for removing coarse particles, for example, purification treatment such as filtering, which will be described later, can be used.

[0073] The first cleaning solution preferably does not contain abrasive particles.

[0074] [Second Cleaning Solution] The second cleaning solution will be described in detail below. The second cleaning solution contains a nonionic surfactant and at least one reducing agent selected from the group consisting of reducing agent O and reducing agent S. The definitions and preferred embodiments of the nonionic surfactant and reducing agent contained in the second cleaning solution are the same as those for the nonionic surfactant and reducing agent in the first cleaning solution. In the second cleaning solution, the mass ratio of the nonionic surfactant content to the reducing agent content is 1.00 to 100.00, preferably 2.00 to 40.00, more preferably 2.50 to 15.00, and even more preferably 3.00 to 5.00, in terms of superior effects of the present invention. The content of the nonionic surfactant is preferably 0.3 to 20% by mass, more preferably 0.4 to 10% by mass, even more preferably 0.6 to 5% by mass, and particularly preferably 0.8 to 3% by mass, relative to the total mass of the second cleaning solution, in terms of superior effects of the present invention. The reducing agent content is preferably 0.05 to 5.0% by mass, more preferably 0.1 to 1.0% by mass, and even more preferably 0.1 to 0.5% by mass, relative to the total mass of the second washing solution.

[0075] The content of fluorine-containing compounds in the second cleaning solution is less than 0.1% by mass, preferably 0.05% by mass or less, and preferably 0.01% by mass or less, relative to the total mass of the second cleaning solution. The lower limit is 0% by mass, and it is also preferable that the second cleaning solution does not contain any fluorine-containing compounds. Examples of fluorine-containing compounds are as described above in the first cleaning solution.

[0076] The definitions, preferred embodiments, and preferred contents of each component other than nonionic surfactants and reducing agents that may be contained in the second cleaning solution (e.g., inorganic acids, chelating agents, solvents, and other additives) are the same as those of the first cleaning solution.

[0077] The pH of the second washing solution is 6.0 or less, preferably 5.5 or less, and more preferably 5.0 or less, in terms of achieving superior effects of the present invention. The lower limit of the pH is 1.8 or higher, preferably 2.0 or higher, more preferably 2.5 or higher, even more preferably 3.5 or higher, and particularly preferably 4.0 or higher, in terms of achieving superior effects of the present invention. When the pH is above the above lower limit, the electron-donating ability of the reducing agent and the chelating ability of the chelating agent to ceria particles are improved, resulting in superior effects of the present invention. It is also preferable that the pH of the second washing solution is equal to or greater than the acid dissociation constant pKa of the reducing agent. If the second washing solution contains a chelating agent, it is also preferable that the pH of the second washing solution is equal to or greater than the acid dissociation constant pKa of the chelating agent. The method for measuring and adjusting the pH is as described above for the first washing solution.

[0078] Preferred embodiments of other properties of the second cleaning solution (e.g., metal content and coarse particle content) are the same as those of the first cleaning solution.

[0079] [Method for Manufacturing the Cleaning Solution] The cleaning solution of the present invention can be manufactured by known methods. The method for manufacturing the cleaning solution will be described in detail below.

[0080] <Preparation Process> The cleaning solution can be manufactured, for example, by mixing the above components. One method for preparing the cleaning solution is to sequentially add a nonionic surfactant, a reducing agent, and any optional components to a container containing purified water, then stir and mix the mixture, and adjust the pH of the mixture by adding an acid as needed. When adding each component to the container, it may be added all at once or in multiple separate additions.

[0081] For preparing the washing solution, a known stirring device and stirring method may be used, either as a stirrer or a disperser. Examples of stirrers include industrial mixers, portable stirrers, mechanical stirrers, and magnetic stirrers. Examples of dispersers include industrial dispersers, homogenizers, ultrasonic dispersers, and bead mills.

[0082] The mixing of each component in the preparation process of the cleaning solution, the purification process described later, and the storage of the manufactured cleaning solution are preferably carried out at 40°C or below, and more preferably at 30°C or below. Furthermore, the lower limit is preferably 5°C or above, and more preferably 10°C or above. By preparing and processing the cleaning solution within the above temperature range, the performance can be maintained stably for a long period of time.

[0083] It is preferable to pre-purify one or more of the raw materials for preparing the washing solution. Examples of purification methods include known methods such as distillation, ion exchange, and filtration. The degree of purification is preferably such that the purity of the raw materials is 99% by mass or higher, and more preferably such that the purity of the stock solution is 99.9% by mass or higher. The upper limit is preferably 99.9999% by mass or lower.

[0084] Methods of purification include, for example, passing the raw material through an ion exchange resin or RO membrane (Reverse Osmosis Membrane), reprecipitation, distillation of the raw material, and filtering. Multiple of the above purification methods may be combined as part of the purification process. For example, after primary purification by passing the raw material through an RO membrane, secondary purification may be performed by passing it through a purification apparatus consisting of a cation exchange resin, anion exchange resin, or mixed-bed ion exchange resin. Furthermore, the purification process may be performed multiple times.

[0085] The filters used for filtering are not particularly limited as long as they have been conventionally used for filtration purposes. For example, filters made of fluororesins such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polyamide resins such as nylon, polyallyl sulfone (PAS), and polyolefin resins such as polyethylene and polypropylene (PP) (including high-density or ultra-high molecular weight) are used. Among these materials, materials selected from the group consisting of polyethylene, polypropylene (including high-density polypropylene), fluororesins (including PTFE and PFA), and polyamide resins (including nylon) are preferred, and fluororesin filters are more preferred. By filtering raw materials using filters made of these materials, highly polar foreign substances that are likely to cause defects can be effectively removed.

[0086] The cleaning solution (including the form of diluted cleaning solution described later) can be filled into any container and stored, transported, and used, as long as corrosiveness or other issues do not pose a problem.

[0087] As for the container, a container with a high degree of cleanliness inside and suppressed elution of impurities from the inner wall of the container's containment section into each liquid is preferred for semiconductor applications. Examples of such containers include, but are not limited to, the "Clean Bottle" series manufactured by Aicello Chemical Co., Ltd. and the "Pure Bottle" manufactured by Kodama Resin Industry Co., Ltd. Furthermore, as a container, the containers exemplified in paragraphs

[0121] to

[0124] of International Publication No. 2022 / 004217 can also be referenced, and the contents of these are incorporated herein by reference.

[0088] These containers are preferably cleaned inside before being filled with the cleaning solution. The cleaning solution used is preferably one in which the amount of metal impurities is reduced. The cleaning solution may be bottled in containers such as gallon bottles or coated bottles after production for transport and storage.

[0089] To prevent changes in the components of the washing solution during storage, the container may be purged with an inert gas (such as nitrogen or argon) with a purity of 99.99995% by volume or higher. Gases with a particularly low water content are preferred. During transportation and storage, the temperature may be room temperature, or it may be controlled to a range of -20°C to 20°C to prevent deterioration.

[0090] It is preferable that all handling, including the manufacture of the cleaning solution, opening and cleaning of the container, filling of the cleaning solution, processing analysis, and measurement, be carried out in a cleanroom. The cleanroom preferably meets the 14644-1 cleanroom standard. It is preferable that it meets any of ISO (International Organization for Standardization) Class 1, ISO Class 2, ISO Class 3, and ISO Class 4, more preferably ISO Class 1 or ISO Class 2, and even more preferably ISO Class 1.

[0091] <Dilution Step> The above cleaning solution may be manufactured in a concentrated state (concentrated cleaning solution) and, after undergoing a dilution step in which it is diluted with a diluent such as water, be used as a cleaning solution to treat the object to be cleaned. Note that a concentrated cleaning solution is also a form of the cleaning solution of the present invention as long as it satisfies the requirements of the present invention.

[0092] It is preferable to perform a purification treatment on the diluent used in the dilution step beforehand. It is also preferable to perform a purification treatment on the diluted washing solution obtained in the dilution step. Examples of purification treatments for the washing solution include ion component reduction treatment using an ion exchange resin or RO membrane, and foreign matter removal using filtering, as described above, and it is preferable to perform one of these treatments.

[0093] The dilution ratio of the cleaning solution in the dilution step can be appropriately adjusted according to the type and content of each component and the object to be cleaned. However, the ratio of the diluted cleaning solution to the undiluted cleaning solution (dilution ratio) is preferably 1 to 10,000 times by mass ratio or volume ratio (volume ratio at 23°C), more preferably 1 to 100 times, and even more preferably 2 to 50 times. Furthermore, for superior residue removal, the cleaning solution is preferably diluted with water (preferably ultrapure water).

[0094] The change in pH before and after dilution (the difference between the pH of the washing solution before dilution and the pH of the diluted washing solution) is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.8 or less. The pH of the washing solution before dilution and the pH of the diluted washing solution are preferably as described above. The pH of the diluted washing solution may be adjusted using a pH adjusting agent (for example, the basic compounds and inorganic acids described above).

[0095] The specific method for diluting the cleaning solution in the dilution step may be carried out in accordance with the cleaning solution preparation step described above. The stirring device and stirring method used in the dilution step may also be carried out using the known stirring device mentioned in the cleaning solution preparation step described above.

[0096] [Object to be cleaned] The cleaning solution of the present invention is used to clean semiconductor substrates that have undergone chemical mechanical polishing (CMP) treatment. Examples of wafers constituting the semiconductor substrate include silicon (Si) wafers, silicon carbide (SiC) wafers, and wafers made of silicon-based materials such as silicon-containing resin wafers (glass epoxy wafers), 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), and antimony (Sb)), and p-type silicon wafers doped with trivalent atoms (e.g., boron (B) and gallium (Ga)). Examples of silicon in silicon wafers include amorphous silicon, single-crystal silicon, polycrystalline silicon, and polysilicon. Among these, wafers made of silicon-based materials such as silicon wafers, silicon carbide wafers, and silicon-containing resin wafers (glass epoxy wafers) are preferred.

[0097] The semiconductor substrate described above preferably includes an insulating film. The insulating film preferably contains silicon, for example, a silicon oxide-based insulating film (for example, silicon dioxide (SiO2) ２ ) film and tetraethyl orthosilicate (Si(OC ２ H５ ) ４ ) films (TEOS films, carbon-doped silicon oxide (SiOC) films, etc.), silicon nitride-based insulating films (for example, silicon nitride (Si ３ N ４ Examples include silicon dioxide (PDI) and silicon carbide nitride (SiNC), and low dielectric constant (Low-k) films (for example, BD (black diamond) films and silicon carbide (SiC) films), with silicon oxide-based insulating films being preferred. The cleaning solution of the present invention has a pH of 6.0 or less and can hydrolyze a portion of the silicon oxide that has interacted with the ceria particles described later and remove it from the substrate surface, making it particularly suitable for cleaning semiconductor substrates containing silicon oxide-based insulating films.

[0098] In addition to the insulating film described above, the semiconductor substrate may also have, for example, a metal wiring film and a barrier metal.

[0099] The above semiconductor substrate may contain a metal. Examples of the metal include at least one metal M selected from the group consisting of tungsten (W), molybdenum (Mo), copper (Cu), cobalt (Co), ruthenium (Ru), aluminum (Al), titanium (Ti), tantalum (Ta), chromium (Cr), hafnium (Hf), osmium (Os), platinum (Pt), nickel (Ni), manganese (Mn), iron (Fe), zirconium (Zr), palladium (Pd), lanthanum (La), niobium (Nb), and iridium (Ir), with at least one metal selected from the group consisting of W, Mo, Cu, Co, and Ru being preferred. The metal preferably exists as a metal layer. Examples of the form of the metal contained in the metal layer include elemental metal M and alloys containing metal M.

[0100] Commonly used wiring metals include, for example, copper (Cu), copper-aluminum alloy (CuAl), copper-titanium alloy (CuTi), copper-chromium alloy (CuCr), copper-manganese alloy (CuMn), copper-tantalum alloy (CuTa), copper-niobium alloy (CuNb), copper-tungsten alloy (CuW), silver (Ag), and gold (Au).

[0101] Examples of barrier metals include tantalum (Ta), tantalum nitride (TaN), titanium nitride (TiN), cobalt (Co), cobalt alloys, ruthenium (Ru), and ruthenium alloys.

[0102] There are no particular restrictions on the method for forming the above-mentioned insulating film and metal film on a wafer constituting a semiconductor substrate, as long as it is a method commonly used in this field. Examples of methods for forming the insulating film include forming a silicon oxide film by heat treatment in the presence of oxygen gas on a wafer constituting a semiconductor substrate, and forming a silicon nitride film by chemical vapor deposition (CVD) by introducing silane and ammonia gases into the silicon oxide film. Examples of methods for forming a metal film include forming a circuit on a wafer having the above-mentioned insulating film using a known method such as resist, and then forming a metal film by plating, physical vapor deposition (PVD), or CVD.

[0103] <CMP Treatment> The cleaning solution is used on objects to be cleaned that have undergone CMP treatment. In other words, the objects to be cleaned are preferably objects containing an insulating film that has undergone CMP treatment, and more preferably semiconductor substrates containing a silicon oxide-based insulating film that has undergone CMP treatment.

[0104] CMP treatment is a process that planarizes the surface of a substrate having a layer selected from, for example, a metal wiring film, a barrier metal, and an insulating film, by a combined chemical action of chemical action using a polishing slurry containing abrasive particles and mechanical polishing. Specifically, for example, the surface of the object to be cleaned is brought into contact with a polishing pad, and the object to be cleaned and the polishing pad are slid relative to each other while supplying polishing slurry to the contact area. As a result, the material on the surface of the object to be cleaned is removed and planarized by the frictional force between the polishing pad, polishing slurry, and the surface of the object to be cleaned, as well as the chemical action of the polishing slurry. The polishing pad is not particularly limited, and pads commonly used in CMP treatment, such as nonwoven fabrics, foamed polyurethanes, and porous fluororesins, can be used. On the surface of the object to be cleaned after CMP treatment, residues such as abrasive particles used in the CMP treatment, polished metal wiring films, and / or metal impurities derived from the barrier metal may remain. In addition, organic matter derived from the CMP cleaning solution used during the CMP treatment may remain as residue. These residues can, for example, short-circuit the wiring and degrade the electrical properties of the semiconductor substrate. Therefore, CMP-treated semiconductor substrates are subjected to a cleaning process to remove these residues from the surface.

[0105] The cleaning solution of the present invention is preferably used as a cleaning solution for cleaning after CMP treatment as described above. In particular, when the cleaning solution of the present invention is applied to a semiconductor substrate that has undergone CMP treatment using ceria particles as abrasive particles, it can efficiently remove residue containing ceria particles. The ceria particles are not particularly limited, for example, Ce ２ O ３ and CEO ３ Particles containing cerium oxide, such as Ce(OH) ４ and Ce(OH) ３ Examples of particles containing cerium hydroxide include, but are not limited to, those described in the Journal of the Japan Society for Precision Engineering, Vol. 84, No. 3, 2018, which describes a CMP-treated substrate.

[0106] <Buff Cleaning> The surface of the object to be cleaned may be subjected to buff cleaning (pad cleaning) after CMP treatment. Buff cleaning is a process that uses a pad to reduce the residue present on the surface of the object to be cleaned. Specifically, the surface of the object to be cleaned, which has been CMP treated, is brought into contact with the pad, and the object to be cleaned and the pad are slid relative to each other while a buff cleaning composition is supplied to the contact area. As a result, the residue on the surface of the object to be cleaned is removed by the frictional force of the pad and the chemical action of the buff cleaning composition. The buff cleaning composition refers to the composition used in the above buff cleaning process.

[0107] The pads used are not particularly limited and can be appropriately selected depending on the type of object to be cleaned, the type of residue to be removed, and the equipment used. The pads may include polishing pads used in CMP (Compound Polishing) treatment, as well as foamed polyurethane buff pads, nonwoven fabric buff pads, suede buff pads, and sponge buff pads. The buff cleaning process described above includes processes known as rinse polishing, pad cleaning, or buff polishing.

[0108] As the above-mentioned buff cleaning composition, known cleaning compositions can be used depending on the type of object to be cleaned and the type and amount of residue to be removed. Examples of components included in the buff cleaning composition include water-soluble polymers such as polyvinyl alcohol, dispersion media such as water, acids such as nitric acid, basic compounds such as amines, surfactants, antibacterial agents, and phosphonic acid compounds. The pad cleaning composition does not contain abrasive particles. The above-mentioned buff cleaning composition may also preferably contain a surfactant in order to have excellent residue removal properties. Examples of surfactants include nonionic surfactants that may be included in the above-mentioned cleaning solution, and the preferred embodiment is the same. Furthermore, the above-mentioned buff cleaning composition may be acidic, basic, or neutral.

[0109] The equipment and conditions used in the buffing process can be appropriately selected from known equipment and conditions depending on the type of material to be processed and the type and amount of residue to be removed. For example, the processing methods described in paragraphs

[0085] to

[0088] of International Publication No. 2017 / 169539 can be used, and these contents are incorporated herein.

[0110] Furthermore, as one embodiment of the buffing process, it is also preferable to apply the buffing process to the object to be cleaned using the cleaning solution of the present invention as the buffing composition. In other words, a method of performing buffing using the cleaning solution of the present invention is also one embodiment of the semiconductor substrate cleaning method of the present invention. The cleaning solution used for buffing may be a diluted cleaning solution.

[0111] The buffing process may be performed only once or two or more times. For example, the object to be cleaned may undergo CMP treatment, followed by buffing using a polishing pad, and then buffing using a buffing pad.

[0112] [Method for cleaning semiconductor substrates] The cleaning solution can be used by known methods. One example of a method for using the cleaning solution is a method of processing an object to be cleaned that includes a step of bringing the object to be cleaned into contact with the cleaning solution. Hereinafter, the step of bringing the object to be cleaned into contact with the cleaning solution will also be called the "contact step". The object to be cleaned is as described above. There are no particular limitations on the method of bringing the object to be cleaned into contact with the cleaning solution, and examples include immersing the object to be cleaned in a cleaning solution in a tank, spraying the cleaning solution onto the object to be cleaned, flowing the cleaning solution over the object to be cleaned, and combinations thereof. The above methods may be appropriately selected depending on the purpose. Contact between the object to be cleaned and the cleaning solution in the contact step may be performed only once or two or more times. If it is performed two or more times, the same method may be repeated or different methods may be combined.

[0113] The temperature of the cleaning solution is not particularly limited, but 10 to 60°C is preferred, and 15 to 50°C is more preferred, in terms of superior cleaning performance and reduced damage to the components.

[0114] The pH of the washing solution and the pH of the diluted washing solution are preferably in the preferred form of the pH described above.

[0115] When processing the objects to be cleaned, methods commonly used in this field may be adopted as appropriate. For example, scrubbing, in which a cleaning member such as a brush is physically brought into contact with the surface of the object to be cleaned while supplying cleaning solution to remove residues, and spin (dropping) cleaning, in which the cleaning solution is dripped onto the object to be cleaned while it is rotated, may be used. In the immersion method, ultrasonic treatment is preferably applied to the object to be cleaned while it is immersed in the cleaning solution, as this can further reduce impurities remaining on the surface of the object to be cleaned.

[0116] The method for processing the items to be washed may be either a single-wafer method or a batch method. The single-wafer method processes the items to be washed one by one, while the batch method processes multiple items to be washed simultaneously.

[0117] The contact time between the object to be cleaned and the cleaning solution can be appropriately adjusted depending on the type and content of each component contained in the cleaning solution, as well as the object and purpose for which the cleaning solution is used. However, 10 to 120 seconds is preferred, 20 to 90 seconds is more preferred, and 30 to 60 seconds is even more preferred.

[0118] The supply rate (feed rate) of the washing solution is preferably 50 to 5000 mL / min, and more preferably 500 to 2000 mL / min.

[0119] In the contact process, mechanical stirring methods may be used to further enhance the cleaning ability of the cleaning solution. Examples of mechanical stirring methods include circulating the cleaning solution over the object to be cleaned, flowing or spraying the cleaning solution over the object to be cleaned, and stirring the cleaning solution with ultrasound or megasonic waves.

[0120] The above processing step is preferably a cleaning step that removes residue from the surface of the object to be cleaned by bringing the object to be cleaned into contact with a cleaning solution. The preferred embodiment of the cleaning step is the same as the preferred embodiment of the contact step described above.

[0121] Furthermore, a step of bringing the object to be cleaned into contact with a rinsing solution (hereinafter also referred to as the "rinsing step") may be performed after the contact step. By performing the rinsing step, the object to be cleaned obtained in the contact step can be washed with the rinsing solution, and residue can be efficiently removed. The rinsing step is preferably performed immediately after the semiconductor substrate cleaning step and is a step of rinsing the object to be cleaned using the rinsing solution. The rinsing step may be performed using the mechanical stirring method described above.

[0122] Examples of rinse solutions include water (preferably DI water), methanol, ethanol, isopropyl alcohol (IPA), N-methylpyrrolidinone, γ-butyrolactone, dimethyl sulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively, an aqueous rinse solution with a pH greater than 8.0 (such as diluted aqueous ammonium hydroxide) may be used.

[0123] The method for bringing the rinsing solution into contact with the object to be cleaned can be similarly applied to the method for bringing the cleaning solution into contact with the object to be cleaned. The contact time between the object to be cleaned and the rinsing solution can be appropriately changed depending on the type and amount of each component contained in the cleaning solution, as well as the object and purpose for which the cleaning solution is used. In practice, 10 to 120 seconds is preferred, 20 to 90 seconds is more preferred, and 30 to 60 seconds is even more preferred.

[0124] Furthermore, a drying step may be performed to dry the object to be cleaned after the above contact step and / or rinsing step. Examples of drying methods include spin drying, a method of passing a drying gas over the object to be cleaned, a method of heating the substrate with heating means such as a hot plate and an infrared lamp, Marangoni drying, Rotagoni drying, IPA drying, and any combination thereof.

[0125] [Method for Manufacturing Semiconductor Devices] The above method for processing the object to be cleaned can be suitably applied to the manufacturing process of semiconductor devices. The above processing method may be carried out in combination before or after other processes performed on the substrate. The above processing method may be incorporated into other processes during the implementation of the above processing method, or the above processing method may be incorporated into other processes. Other processes include, for example, processes for forming structures such as metal wiring, gate structures, source structures, drain structures, insulating films, ferromagnetic layers, and non-magnetic layers (e.g., layer formation, etching, chemical mechanical polishing, and modification), resist formation processes, exposure processes, removal processes, heat treatment processes, cleaning processes, and inspection processes.

[0126] The above processing method may be performed at any stage of the backend process (BEOL), middle process (MOL), or frontend process (FEOL), and is preferably performed in the frontend process or middle process.

[0127] The present invention will be described in more detail below based on examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below.

[0128] In the following examples, the pH of the cleaning solution was measured at 25°C in accordance with JIS Z8802-1984 using a pH meter (Horiba, Ltd., model "F-74"). Furthermore, in the preparation of the cleaning solutions in the examples and comparative examples, the handling of containers, preparation, filling, storage, and analytical measurements of the cleaning solutions were all carried out in a cleanroom meeting ISO Class 2 or lower standards.

[0129] [Raw materials for the cleaning solution] The following compounds were used to manufacture the cleaning solution. In the examples and comparative examples, all components used were classified as semiconductor grade or equivalent high-purity grade.

[0130] [Nonionic Surfactants] ・Tween 80 (Polyoxyethylene sorbitan monooleate, manufactured by Fujifilm Wako Co., Ltd.) ・Tween 20 (Polyoxyethylene sorbitan monolaurate, manufactured by Fujifilm Wako Co., Ltd.) ・PEG 2000 (Polyethylene glycol, number average molecular weight 2000, manufactured by Fujifilm Wako Co., Ltd.) ・Emulgen A-500 (Polyoxyethylene distyrenated phenyl ether, manufactured by Kao Corporation) ・PVP K12 (Polyvinylpyrrolidone, weight average molecular weight 5000, manufactured by Ashland Co., Ltd.)

[0131] [Reducing agents] ・L-AA (L-ascorbic acid, reducing agent O) ・Pyrogallol (manufactured by Fujifilm Wako Co., Ltd., reducing agent O) ・Dopamine hydrochloride (manufactured by Fujifilm Wako Co., Ltd., reducing agent O) ・Glucose (manufactured by Fujifilm Wako Co., Ltd., reducing agent O) ・Dithiodiglycolic acid (manufactured by Tokyo Chemical Industry Co., Ltd., reducing agent S) ・DEHA (diethylhydroxylamine, having one hydroxyl group) ・HA (hydroxylamine, having one hydroxyl group)

[0132] [Inorganic acid] ・HNO ３ ・H ２ SO ４ ・H ３ PO ４ ・HF (fluorine-containing compound)

[0133] [Other ingredients] ・HEDP (1-hydroxyethylidene-1,1'-diphosphonic acid, phosphonic acid chelating agent) ・CA (citric acid)

[0134] [Preparation of Cleaning Solution] The method for producing the cleaning solution will be described below. A high-concentration cleaning solution was prepared by diluting the above compound to the composition shown in the table below. This solution was then diluted, and a pH adjuster (ammonia water) was added as needed to achieve the pH shown in the table below. The solution was then thoroughly stirred to obtain the cleaning solutions for each example and comparative example. In the cleaning solution, the remaining components (residue) that are not explicitly listed as components of the cleaning solution in the table are deionized water or a pH adjuster. In addition, the content of the fluorine-containing compound in all cleaning solutions except Comparative Example 12 was 0% by mass.

[0135] [Cleaning of the object to be cleaned] Using TriboLabCMP (polishing device, manufactured by Bruker), polishing solution 1 with the following composition is used as the polishing solution, with a polishing pressure of 2 psi (138 hPa) and a polishing solution supply rate of 50 mL / (min·cm). ２ Three 2cm square silicon wafers with a TEOS film were polished under the condition of a polishing time of 60 seconds to perform CMP treatment. The cleaning solution for each example or comparative example was divided into three parts and adjusted to room temperature (23°C). One CMP-treated wafer was placed in each of the divided cleaning solutions and immersed for 600 seconds while stirring with a stirrer. Then, after washing with deionized water for 10 seconds, it was dried. (Polishing solution 1) - Ceria particles (CESL-30N, Daiichi Kigenso Kagaku Kogyo): 0.05 mass% - Polyvinylpyrrolidone K30: 0.3 mass% - 10% ammonia water: 0.002 mass% - Water: remainder - pH 6

[0136] [Evaluation] [Ceria Particle Removal Performance] After immersing a wafer that had undergone CMP treatment as described in [Cleaning of Objects to be Cleaned] above, 10 mL of the cleaning solution was used as the ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) measurement stock solution. The ICP-MS measurement stock solution was diluted 10 times with 1% nitric acid, and this diluted solution was used as the ICP-MS measurement dilution. The Ce atom content (mass ppb) in the obtained ICP-MS measurement dilution was measured using an Agilent 7900 ICP-MS (manufactured by Agilent Technologies). ICP-MS measurement of the above dilution was performed for each of the three cleaning solutions, and the arithmetic mean of the obtained Ce atom content (N=3) was taken as the ceria particle removal concentration (mass ppb). A higher ceria particle removal concentration indicates better ceria particle removal performance of the cleaning solution. In practice, a ceria particle removal concentration of 30 mass ppb or higher is preferable.

[0137] [Substrate Solubility] For TEOS-coated wafers (300 mm, Advantech Co., Ltd., part number: PE-CVD-TEOS 10000A) cut into 2 cm squares, the TEOS film thickness (Å) before immersion in the cleaning solution was measured using a spectroscopic ellipsometer (J.A. Woolam Japan Co., Ltd., model number: M-2000XI). After measurement, the wafers were immersed in 20 mL of the cleaning solution of each example or comparative example at 25°C for 1 hour (60 min). After immersion, the wafers were removed, rinsed with pure water, dried by nitrogen blowing, and the film thickness (Å) after immersion was measured using the ellipsometer. The etching rate ER of the TEOS film was calculated based on the following formula. A smaller ER indicates lower substrate solubility. ER (Å / min) = (Film thickness before immersion - Film thickness after immersion) / 60

[0138] [Results] The composition and evaluation results of each example and cleaning solution are shown in the table below. In the table, the "Nonionic Surfactant / Inorganic Acid" column shows the mass ratio of the nonionic surfactant content to the inorganic acid content (nonionic surfactant content / inorganic acid content). In the table, the "Nonionic Surfactant / Reducing Agent" column shows the mass ratio of the nonionic surfactant content to the reducing agent content (nonionic surfactant content / reducing agent content). In the table, the value in the pH column shows the pH of the cleaning solution at 25°C as measured by the pH meter described above. In the table, "<1" in the "ER (Å / min)" column means that the etching rate ER of the TEOS film obtained in the above measurement is less than 1 Å / min. Table 2 is a continuation of Table 1, and Table 4 is a continuation of Table 3. For example, the cleaning solution of Example 1 contains 0.3% by mass of the ionic surfactant Tween 20, 0.28% by mass of the reducing agent L-AA, 0.021% by mass of the chelating agent HEDP, and the inorganic acid HNO ３ It contains 0.05% by mass, has a pH of 4.1, a ceria particle removal concentration of 30.0 ppb by mass, and an ER of <1.

[0139]

[0140]

[0141]

[0142]

[0143] From the results in the table above, it was confirmed that the cleaning solution of the present invention exhibits excellent removal of ceria particles after CMP treatment using ceria particles, and suppresses substrate dissolution. On the other hand, it was confirmed that the cleaning solution of the comparative example either did not meet the desired level of ceria particle removal after CMP treatment using ceria particles, or exhibited high substrate dissolution.

[0144] From comparisons of Examples 5-7, 18-20, and 21-23, it was confirmed that the effects of the present invention are superior when the content of the nonionic surfactant is 0.6-5% by mass relative to the total mass of the cleaning solution. From comparisons of Examples 5-7, 18-20, and 21-23, it was confirmed that the effects of the present invention are superior when the mass ratio of the content of the nonionic surfactant to the content of the reducing agent is 2.0-40.0. From comparisons of Examples 24 and 26, it was confirmed that the effects of the present invention are even superior when the pH of the cleaning solution is 4.0 or less. From comparisons of Examples 12-15, it was confirmed that the effects of the present invention are superior when the reducing agent O includes ascorbic acid or its salt, catechol, pyrogallol, gallic acid, dopamine, or dopamine hydrochloride. From comparisons of Examples 1-4 and 5-9, it was confirmed that the effects of the present invention are superior when the nonionic surfactant includes Tween 80.

Claims

1. A cleaning solution for use on a semiconductor substrate subjected to chemical mechanical polishing, comprising: a nonionic surfactant; a reducing agent having two or more hydroxyl groups; and at least one reducing agent selected from the group consisting of a disulfide bond or a thiol group and a carboxyl group, wherein the content of the nonionic surfactant is 0.3 to 20% by mass of the total mass of the cleaning solution; the pH is 1.8 or higher and 6.0 or lower; and the content of a fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution.

2. A cleaning solution for use on a semiconductor substrate subjected to chemical mechanical polishing, comprising a nonionic surfactant, a reducing agent having two or more hydroxyl groups, and at least one reducing agent selected from the group consisting of a disulfide bond or a thiol group and a carboxyl group, wherein the mass ratio of the nonionic surfactant content to the content of the reducing agent is 1.00 to 100.00, the pH is 1.8 to 6.0, and the content of a fluorine-containing compound is less than 0.1% by mass of the total mass of the cleaning solution.

3. The washing solution according to claim 1 or 2, wherein the reducing agent having two or more hydroxyl groups comprises at least one selected from the group consisting of ascorbic acid compounds, polyphenol compounds, hydrogen peroxide, and sugars.

4. The cleaning solution according to claim 1 or 2, wherein the nonionic surfactant is a polyether-based surfactant.

5. The cleaning solution according to claim 1 or 2, further comprising an inorganic acid.

6. The cleaning solution according to claim 5, wherein the mass ratio of the content of the nonionic surfactant to the content of the inorganic acid is greater than 1.

7. The cleaning solution according to claim 1 or 2, further comprising a chelating agent.

8. The cleaning solution according to claim 1 or 2, wherein the semiconductor substrate includes a silicon oxide-based insulating film.

9. The cleaning solution according to claim 1 or 2, wherein the chemical mechanical polishing treatment is a treatment using ceria particles.

10. A method for cleaning a semiconductor substrate, comprising the step of cleaning a semiconductor substrate that has been subjected to chemical mechanical polishing using the cleaning solution described in claim 1 or 2.

11. A method for manufacturing a semiconductor device, comprising the method for cleaning a semiconductor substrate as described in claim 10.

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