Cleaning liquid, cleaning method, and method for manufacturing semiconductor element

Abstract

The present invention provides: a cleaning liquid which is excellent in terms of foaming of the cleaning liquid and removability of abrasive grains, and which can effectively remove abrasive grains and organic components adhering to an object to be cleaned; a cleaning method in which the cleaning liquid is used; and a method for manufacturing a semiconductor element.　The present invention specifically provides a cleaning liquid for removing a cerium compound, the cleaning liquid containing a water-soluble polymer (A) that includes a water-soluble polymer (a1) having a sulfonic acid group. The cleaning liquid has a pH of 7 or less, and an aqueous solution of the water-soluble polymer (A) having a concentration of 0.1 mass% has a surface tension of 68 mN / m or more at 22°C as determined by a pendant drop method.

Description

Cleaning solution, cleaning method, and semiconductor element manufacturing method

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

[0002] In semiconductor devices, such as semiconductor devices, the integration density is increasing to improve performance, resulting in miniaturization of semiconductor elements such as transistors and multilayer wiring. One example of a semiconductor element manufacturing method involves sequentially depositing a conductive film, an insulating film, a resist film, etc. on a semiconductor substrate such as a silicon wafer, forming a circuit pattern through processes such as lithography and etching, and then depositing an oxide film, followed by planarization using chemical mechanical polishing (CMP). Furthermore, a new layer may be stacked on the flat surface to form a multilayer semiconductor element. In CMP, polishing is performed using a slurry-like abrasive containing abrasive particles (also referred to as abrasive grains). In CMP of silicon compound films such as silicon dioxide films and silicon nitride films, cerium compound-containing particles are preferably used as abrasive grains to improve the polishing rate. After the CMP process, unwanted components such as abrasive components (e.g., abrasive grains and organic components such as polymers) and polishing debris may be present on the surface of the semiconductor element. Therefore, after the CMP process, the semiconductor element is typically cleaned with a cleaning solution. Generally, cerium compound-containing particles are difficult to remove because they form bonds with the surface of silicon compound films such as silicon dioxide films and silicon nitride films during the CMP process, or they adhere strongly to the surface due to the attractive force of the zeta potential under acidic conditions. For this reason, cleaning has traditionally been performed using strong chemicals such as diluted hydrofluoric acid and sulfuric acid / hydrogen peroxide, but efforts are underway to develop cleaning solutions that are easier to handle.

[0003] For example, Patent Document 1 describes a specific cleaning composition containing a specific polymer having a carboxylic acid group and a sulfonic acid group, a specific polymer containing a structural unit derived from an aromatic monomer having a sulfonic acid group, sulfuric acid, a reducing agent, and water.

[0004] Japanese Patent Application Laid-Open No. 2018-046153

[0005] The cleaning solution of Patent Document 1 is said to have improved cleaning properties for ceria due to the combination of two types of polymers. However, this cleaning solution has issues with handling, such as low surface tension and poor foam removal, especially under acidic conditions.

[0006] The present disclosure aims to provide a cleaning liquid that has excellent abrasive grain removal properties while suppressing foaming of the cleaning liquid and that can effectively remove abrasive grains and organic components adhering to an object to be cleaned, a cleaning method using the cleaning liquid, and a method for manufacturing semiconductor elements.

[0007] The present disclosure provides the following cleaning solution for removing abrasive grains, a cleaning method, and a method for manufacturing semiconductor devices. [1] A cleaning solution for removing cerium compounds, comprising a water-soluble polymer (A) including a water-soluble polymer (a1) having a sulfonic acid group, having a pH of 7 or less, and a surface tension of a 0.1% by mass aqueous solution of the water-soluble polymer (A) at 22°C measured by the pendant drop method of 68 mN / m or more. [2] The cleaning solution of [1] above, wherein the water-soluble polymer (a1) having a sulfonic acid group has one or more repeating units selected from aromatic sulfonic acid, perfluoroalkyl sulfonic acid, and salts thereof. [3] The cleaning solution of [1] or [2] above, wherein the ratio (Nc / Ns) of the number of carbon atoms excluding counter cations of sulfonic acid groups contained in a repeating unit having at least one sulfonic acid group contained in the water-soluble polymer (a1) having a sulfonic acid group to the total number (Ns) of sulfonic acid groups and their salts is 7 to 15. [4] The cleaning solution according to any one of [1] to [3], further containing a reducing compound (B). [5] The cleaning solution according to [4], wherein the reducing compound (B) comprises one or more compounds selected from the group consisting of gallic acid, gallic acid esters, pyrogallol, ascorbic acid, uric acid, diphosphorous acid, and oxalic acid. [6] The cleaning solution according to any one of [1] to [5], further containing the water-soluble polymer (A) and an acidic compound (C) other than the reducing compound (B). [7] The cleaning solution according to [6], wherein the acidic compound (C) comprises an organic compound having one or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less, and one or more selected from sulfuric acid, nitric acid, and phosphoric acid. [8] The cleaning solution of [6] above, wherein the acidic compound (C) contains an organic compound having two or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less. [9] The cleaning solution of any of [1] to [8] above, wherein the pH is 1 to 5.

[10] The cleaning solution of any of [1] to [9] above, further containing a preservative.

[11] The cleaning solution of any of [1] to

[10] above, wherein the water-soluble polymer (A) having a sulfonic acid is contained in an amount of 0.001 to 10 mass %.

[12] The cleaning solution according to any one of [1] to

[11] above, wherein the reducing compound (B) is contained in an amount of 0.001 to 10% by mass.

[13] The cleaning solution according to any one of [1] to

[12] above, wherein the acidic compound (C) is contained in an amount of 0.001 to 10% by mass.

[14] The cleaning solution according to any one of [1] to

[13] above, wherein the Ross-Miles bubble height at 25°C is 30 mm or less.

[15] The cleaning solution according to any one of [1] to

[14] above, wherein the amount of Cu elution is 3.0 ppm or less when a silicon substrate having a Cu film formed thereon is immersed in 12 mL of an aqueous solution containing the water-soluble polymer (A) at 25°C for 10 minutes.

[16] The cleaning solution according to any one of [1] to

[15] above, wherein the cleaning solution is used to clean a semiconductor substrate having a cerium compound attached thereto.

[17] The cleaning solution according to

[16] above, wherein at least a part of the semiconductor substrate has an exposed surface including a metal wiring.

[18] The cleaning solution according to any one of [1] to

[15] above, which is for cleaning a brush used for cleaning a semiconductor substrate, the brush having a cerium compound attached thereto.

[19] The cleaning solution according to any one of [1] to

[15] above, which is for cleaning an object whose surface has been polished with an abrasive containing cerium compound-containing particles.

[20] The cleaning solution according to

[19] above, wherein the cerium compound-containing particles have an average particle size of 300 nm or less.

[21] A cleaning method comprising cleaning a surface to be cleaned having a cerium compound attached thereto with the cleaning solution according to any one of [1] to

[15] above.

[22] A method for manufacturing a semiconductor element, which comprises preparing a semiconductor substrate polished with an abrasive containing cerium compound-containing particles, and cleaning the polished surface of the semiconductor substrate with the cleaning solution according to any one of [1] to

[15] above.

[0008] According to the present disclosure, there are provided a cleaning solution that has excellent abrasive grain removal properties while suppressing foaming, and that can effectively remove abrasive grains and organic components adhering to an object to be cleaned, a cleaning method using the cleaning solution, and a method for manufacturing semiconductor devices. Also provided are a cleaning solution that, when used on a substrate having metal wiring, suppresses corrosion of the metal wiring by adding an appropriate additive, a cleaning method using the cleaning solution, and a method for manufacturing semiconductor devices.

[0009] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments, and other embodiments may also fall within the scope of the present invention as long as they are consistent with the spirit of the present invention. In this disclosure, unless otherwise specified, the numerical ranges indicated by "to" include the numerical values ​​before and after the range as the lower and upper limits. "Water-soluble" means that 100 mg or more is dissolved in 100 g of water at 25°C. "(Meth)acrylic" is a general term for "methacrylic" and "acrylic," and this also applies to (meth)acryloyl, (meth)acrylate, etc. Furthermore, "water-soluble polymer (a1) having sulfonic acid" may be referred to as "water-soluble polymer (a1)," and "water-soluble polymer (A) containing water-soluble polymer (a1) having sulfonic acid" may be referred to as "water-soluble polymer (A)."

[0010] [Cleaning Solution] The cleaning solution of the present disclosure is a cleaning solution for removing cerium compounds, characterized in that it contains a water-soluble polymer (A) including a water-soluble polymer (a1) having a sulfonic acid group, has a pH of 7 or less, and has a surface tension of 68 mN / m or more at 22°C of a 0.1 mass% aqueous solution of the water-soluble polymer (A) as measured by the pendant drop method.

[0011] In this cleaning solution, the water-soluble polymer (a1) appropriately controls the zeta potential, inhibiting adsorption or bonding between the object to be cleaned and the cerium compound, thereby facilitating the release of the cerium compound and organic components adhering to the object to be cleaned. Furthermore, the sulfonic acid group contained in the water-soluble polymer (a1) is less likely to be protonated under acidic conditions than carboxylic acid groups, maintaining its ionic character, suppressing aggregation of sulfonic acid groups, and maintaining surface tension. Furthermore, by maintaining the ionic character of the sulfonic acid group, this cleaning solution also has excellent cleaning performance under acidic conditions. Furthermore, this cleaning solution contains a water-soluble polymer (A) whose surface tension at 22°C of a 0.1% by mass aqueous solution measured by the pendant drop method is 68 mN / m or more, preferably 70 mN / m or more, thereby suppressing foaming and facilitating the removal of cleaning solution components from the surface of the object to be cleaned. As a result, abrasive components can be effectively removed from the surface of the object to be cleaned. This cleaning solution can be suitably used for removing cerium compounds. In particular, it can effectively remove cerium compound-containing particles bonded to or attached to the substrate surface after the CMP process. Furthermore, because this cleaning solution has good foam removal, it is suitable for cleaning brushes used in CMP processes for cleaning semiconductor substrates, and can clean the brushes in a short time. The cerium compound includes cerium compound-containing particles and abrasive grains containing a cerium compound. Examples of cerium compounds include ceria and cerium hydroxide.

[0012] <pH> The pH of the present cleaning solution is 7 or less from the viewpoint of improving cleaning performance, and the pH is preferably 1 to 6, more preferably 1 to 5, from the viewpoint of further improving cleaning performance. The pH of the present cleaning solution may be adjusted by adjusting the type or content ratio of the water-soluble polymer (A), or an acidic compound described below may be used. In the present disclosure, pH is a value at 25°C and can be measured using a pH meter.

[0013] <Surface Tension> The surface tension of the water-soluble polymer (A) contained in the present cleaning solution is characterized by being 68 mN / m or more in a 0.1% by mass aqueous solution at 22°C, from the viewpoints of suppressing foaming and improving cleaning performance. The surface tension of the present cleaning solution can be adjusted by the structure and mass-average molecular weight of the water-soluble polymer (A). The upper limit of the surface tension is not particularly limited, but is typically 72.4 mN / m, which is the surface tension of water at 22°C. In the present disclosure, the surface tension is measured by the pendant drop method at 22°C. Specifically, a liquid (cleaning solution) is dropped from the tip of a vertically placed capillary (syringe needle), and the shape of the largest hanging drop (drop) that does not fall is photographed. The image is analyzed using the ds / de method to calculate the surface tension. The aqueous solution for surface tension measurement is prepared by dissolving the water-soluble polymer (A) used in the cleaning solution in water to a concentration of 0.1% by mass. When the water-soluble polymer (A) contains two or more polymers, the ratio of each polymer is adjusted to the same ratio as that of the cleaning solution. The aqueous solution may be acidic, and the pH may be adjusted to 7 or less.

[0014] The cleaning solution preferably has a Ross Miles foaming height of 30 mm or less. A Ross Miles foaming height of 20 mm or less is more preferable, and a Ross Miles foaming height of 5 mm or less is particularly preferable. When the Ross Miles foaming height is within the above range, foaming is less likely to occur in the piping or equipment when the cleaning solution is diluted and supplied. The Ross Miles foaming height is measured by the following method described in JIS K 3362. 50 mL of cleaning solution is placed at the bottom of a 50 mm diameter glass tube, and a fixed amount (200 mL) of cleaning solution is dropped from the top of the glass tube over 30 seconds. The height of the resulting foam (mm) is measured 30 seconds after the drop to measure foaming power. The higher the foam height, the easier it is to foam.

[0015] When a silicon substrate having a Cu film formed thereon is immersed in 12 mL of an aqueous solution containing the water-soluble polymer (A) at 25°C for 10 minutes, the amount of Cu elution from this cleaning agent is preferably 3.0 ppm or less. The amount of Cu elution is more preferably 2.5 ppm or less, and particularly preferably 2.0 ppm or less. When the amount of Cu elution is within the above range, the etching rate of the Cu film is 0.5 nm / min or less, which is within a range in which the cleaning solution does not significantly change the thickness of the Cu film.

[0016] The cleaning solution contains at least the water-soluble polymer (A) and water, and may further contain other components as long as the effects of the present invention are achieved. Each component that can be contained in the cleaning solution will be described below.

[0017] <Water-soluble polymer (A)> The water-soluble polymer (A) contains at least a water-soluble polymer (a1) having a sulfonic acid, and may contain another water-soluble polymer (a2). Each water-soluble polymer will be described below.

[0018] (Water-soluble polymer (a1) having sulfonic acid group) The water-soluble polymer (a1) is a water-soluble polymer having at least one sulfonic acid group in the molecule. The sulfonic acid group in the water-soluble polymer (a1) may be in the form of an ion or a salt.

[0019] When the sulfonic acid group forms a salt, specific examples of the counter cation include alkali metal ions such as sodium ion and potassium ion; ammonium ion; phosphonium ion; sulfonium ion; and the like. Among these, ammonium ion is preferred from the viewpoint of further improving cleaning properties. Specific examples of the ammonium ion include methylammonium ion, dimethylammonium ion, trimethylammonium ion, ethylammonium ion, triethylammonium ion, n-propylammonium ion, isopropylammonium ion, n-butylammonium ion, tert-butylammonium ion, hexylammonium ion, 2-hydroxyethylammonium ion, N,N-dimethyl-N-(2-hydroxyethyl)ammonium ion, N-methyl-N-(2-hydroxyethyl)ammonium ion, di(2-hydroxyethyl)ammonium ion, N-methyl-N,N-di(2-hydroxyethyl)ammonium ion, N,N,N-tri ... N-methyl-N-(2,3-dihydroxypropyl)ammonium ion, N,N-dimethyl-N-(2,3-dihydroxypropyl)ammonium ion, triisobutylammonium ion, triisopentylammonium ion, triisooctylammonium ion, imidazolium ion, N-methylimidazolium ion, tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, ethyltrimethylammonium ion, diethyldimethylammonium ion, methyltriethylammonium ion, and quaternary ammonium ion NH ４ ＋ Examples include:

[0020] In order to further improve cleaning properties, the water-soluble polymer (a1) preferably has one or more repeating units selected from aromatic sulfonic acid, perfluoroalkyl sulfonic acid, and salts thereof. Examples of the repeating unit of aromatic sulfonic acid include structures of the following formulas (1) and (2): -CH ２ -CH(-Ar１ SO ３ Z １ )-…(1)-CH ２ (-Ar ２ SO ３ Z １ ) - ... (2) where Ar １ and Ar ２ represents a divalent aromatic group which may have a substituent, and Z １ is a hydrogen atom or a cation.

[0021] Furthermore, examples of the repeating unit of perfluoroalkylsulfonic acid include the structure of the following formula (3): —CF ２ -CF[-O-(R １ O) ｎ -R ２ -SO ３ Z １ ]- … (3) However, R １ is a fluoroalkylene group having 1 to 6 carbon atoms which may be branched, and R ２ is a fluoroalkylene group having 1 to 6 carbon atoms; Z １ is a hydrogen atom or a cation, and n is an integer of 0 to 6.

[0022] Ar １ and Ar ２ Examples of the aromatic ring in Ar include benzene, naphthalene, and anthracene. From the viewpoint of further improving cleaning properties, benzene or naphthalene is preferred, and naphthalene is more preferred. １ and Ar ２ Examples of the substituent that may be possessed by Z include an alkyl group having 1 to 6 carbon atoms and a halogen atom. １ The cation in R is the same as the counter cation described above. １ A specific example of this is CF ２ , C.F. ２ CF ２ , C.F. ２ CF ２ CF ２ , C.F. ２ CF (CF ３ ), CF ２ CF ２ CF ２ CF ２etc. ２ A specific example of this is CF ２ , C.F. ２ CF ２ , C.F. ２ CF ２ CF ２ , C.F. ２ CF ２ CF ２ CF ２ etc.

[0023] The repeating units of formula (1) and formula (3) can be suitably obtained by the production method (I) described below, and the repeating unit of formula (2) can be suitably obtained by the production method (II) described below.

[0024] From the viewpoint of further improving the cleaning properties and facilitating the control of the surface tension of a 0.1% by mass aqueous solution of the water-soluble polymer (A) to 68 mN / m or more, the ratio (Nc / Ns) of the number of carbon atoms (Nc) contained in the repeating unit having a sulfonic acid group in the water-soluble polymer (a1) to the total number (Ns) of sulfonic acids and salts thereof is preferably from 7 to 15, more preferably from 8 to 12. Note that the carbon atoms contained in the counter cation of the sulfonic acid group are not included in the number of carbon atoms in the repeating unit having a sulfonic acid group contained in the water-soluble polymer (a1).

[0025] In the case of a fluoropolymer containing a repeating unit of perfluoroalkylsulfonic acid, the TQ value (volume flow rate) is preferably 200 to 300° C., more preferably 220 to 300° C., and particularly preferably 240 to 290° C., from the viewpoints of cleaning properties and prevention of redeposition of abrasive grains. Here, the TQ value is an index of the molecular weight of a fluoropolymer having sulfonic acid groups, and is the value obtained when the extrusion amount of the fluoropolymer is 100 mm when melt-extrusion is carried out using a nozzle having a length of 1 mm and an inner diameter of 1 mm under the condition of an extrusion pressure of 2.94 MPa. ３ / second. If the TQ value is equal to or greater than the lower limit of the above range, the fluoropolymer has a sufficient molecular weight, and particles can be dispersed effectively. If the TQ value is equal to or less than the upper limit of the above range, the solubility of the fluoropolymer is improved, and a uniform solution can be prepared as a cleaning liquid.

[0026] Furthermore, in order to further improve cleaning properties and easily control the surface tension of a 0.1% by mass aqueous solution of the water-soluble polymer (A) to 68 mN / m or more, the weight average molecular weight (Mw) of the water-soluble polymer (a1) is preferably 5,000 to 800,000 for the above-mentioned fluoropolymers, more preferably 10,000 to 500,000, and particularly preferably 50,000 to 300,000. For other sulfonic acid polymers, it is preferably 1,000 to 500,000, more preferably 1,500 to 300,000, and particularly preferably 2,000 to 50,000. The Mw is a value determined by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0027] The water-soluble polymer (a1) is preferably a polymer obtained by the following production method (I) or (II) in terms of improving cleanability and facilitating adjustment of the Nc / Ns and Mw. (I) A polymer obtained by (co)polymerizing a monomer having a sulfonic acid group with other monomers used as needed. (II) A polymer obtained by condensing an aromatic sulfonic acid with other aromatic compounds used as needed and formaldehyde.

[0028] (Production Method (I)) Production method (I) is a method in which a monomer having an ethylenically unsaturated bond and a sulfonic acid group is mixed with other monomers as needed, an initiator is added, and polymerization is carried out by a known polymerization method such as solution polymerization, bulk polymerization, or various radical polymerizations. Solution polymerization is preferred in terms of ease of adjusting the Mw of the water-soluble polymer (a1). In the case of a block polymer, for example, a block of a monomer having a sulfonic acid may be synthesized first, and other monomers may be mixed with this block and polymerized, or the order of synthesis in this production method may be reversed.

[0029] Examples of the monomer having a sulfonic acid group include monomers having aromatic sulfonic acids such as styrenesulfonic acid and vinylnaphthalenesulfonic acid; vinylsulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methyl-1-propanesulfonic acid, 2-sulfoethyl (meth)acrylate, sulfopropyl (meth)acrylate, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 2-propene-1-sulfonic acid, perfluorosulfonic acid monomers, and salts thereof, and these may be used alone or in combination of two or more.

[0030] By using the above-mentioned monomer having an aromatic sulfonic acid group, a repeating unit of the aromatic sulfonic acid represented by the above formula (1) can be obtained.

[0031] The perfluorosulfonic acid monomer may be a monomer represented by the following formula (4): CF ２ =CF-O-(R １ O) ｎ -R ２ -SO ３ Z １ ... (4) However, R １ , R ２ , Z １ and n are the same as those in the above formula (3). By using the above monomer having an aromatic sulfonic acid group, a repeating unit of perfluoroalkylsulfonic acid represented by the above formula (3) is obtained.

[0032] Specific examples of perfluorosulfonic acid monomers of formula (4) include: CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ SO ３ HCF ２ = CFOCF ２ CF ２ CF ２ OCF ２ CF ２ SO ３ HCF ２ = CFOCF ２ CF ２ OCF２ CF ２ SO ３ HCF ２ = CFOCF ２ CF ２ SO ３ HCF ２ = CFOCF ２ CF ２ CF ２ SO ３ HCF ２ = CFOCF ２ CF ２ CF ２ CF ２ CF ２ SO ３ H

[0033] In order to adjust the ratio of sulfonic acid groups in the water-soluble polymer (a1), a monomer not having a sulfonic acid group, preferably a monomer not having an acidic group, may be combined as necessary. Specific examples of monomers not having a sulfonic acid group include vinyl monomers such as ethylene, vinyl chloride, vinylidene chloride, styrene, methylstyrene, vinyltoluene, and p-t-butylstyrene; (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate; acrylamide monomers such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, and N,N-diethyl (meth)acrylamide; and bifunctional vinyl monomers such as maleic anhydride, monoethyl maleic acid, monoethyl fumaric acid, diethyl maleic acid, and diethyl fumaric acid. These monomers are preferably used in combination with a monomer having an aromatic sulfonic acid group.

[0034] Furthermore, as a monomer having no sulfonic acid group that can be used in combination with the perfluorosulfonic acid monomer, a monomer represented by the following formula (5) can be mentioned: CF ２ = CFL １ ... (5) However, L １ is a fluorine atom, a chlorine atom, or O—(R １１ O) ｎ１ -R １２ and R １１is a fluoroalkylene group having 1 to 6 carbon atoms which may be branched, and R １２ is a fluoroalkyl group having 1 to 6 carbon atoms; and n1 is an integer of 0 to 6.

[0035] R １１ The fluoroalkylene group in R is preferably a perfluoroalkylene group. １２ The fluoroalkylene group in R is preferably a perfluoroalkylene group. １１ Specific examples of １ It is the same as R １２ A specific example of this is CF ３ , C.F. ２ CF ３ , C.F. ２ CF ２ CF ３ , C.F. ２ CF ２ CF ２ CF ３ Examples include:

[0036] Specific examples of the monomer represented by formula (5) include the following: CF ２ =CF ２ CF ２ = CFOCF ３ CF ２ = CFOCF ２ CF ３ CF ２ = CFOCF ２ CF ２ CF ２ OCF ２ CF ３

[0037] (Production Method (II)) The production method (II) is a method in which an aromatic sulfonic acid, other aromatic compounds used as needed, and formaldehyde are mixed and heated in the presence of a catalyst to cause addition condensation.

[0038] The aromatic sulfonic acid may be a compound represented by the following formula (6): ３ SO ３ Z １ ... (6) where Ar ３ represents a monovalent aromatic group which may have a substituent, and Z１ is a hydrogen atom or a cation.

[0039] By using the aromatic sulfonic acid, the repeating unit of the aromatic sulfonic acid represented by the formula (2) is obtained. ３ Examples of the aromatic ring in Ar include benzene, naphthalene, and anthracene. From the viewpoint of further improving cleaning properties, benzene or naphthalene is preferred, and naphthalene is more preferred. ３ Examples of the substituent that may be present include an alkyl group having 1 to 6 carbon atoms and a halogen atom. １ The cation in is the same as the counter cation described above.

[0040] In order to adjust the ratio of sulfonic acid in the water-soluble polymer (a1), an aromatic compound not having a sulfonic acid group, preferably an aromatic compound not having an acidic group, may be combined as necessary. Examples of such aromatic compounds include benzene, naphthalene, anthracene, etc., which may have a substituent, and examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a halogen atom, etc. The content of the water-soluble polymer (a1) is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass or more, and particularly preferably 99.9% by mass or more, based on the total amount (100% by mass) of the water-soluble polymer (A). It may also be 100% by mass.

[0041] (Another Water-Soluble Polymer (a2)) The water-soluble polymer (A) may be composed of a water-soluble polymer (a1) having a sulfonic acid group, or may contain another water-soluble polymer (a2) within the scope of the effects of the present invention. Examples of the other water-soluble polymer (a2) include polymers having one or more polar groups selected from a hydroxyl group, a carboxylic acid group, and an amino group.

[0042] The content of the other water-soluble polymer (a2) can be appropriately adjusted within the range of 0.01 to 10% by mass relative to the total amount (100% by mass) of the water-soluble polymer (A). On the other hand, for example, polymers having carboxylic acid groups tend to be easily protonated under acidic conditions, which results in a tendency for the surface tension and cleaning performance to decrease. From this viewpoint, the content of the other water-soluble polymer (a2) is preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less, relative to the total amount of the water-soluble polymer (A).

[0043] The content of the water-soluble polymer (A) in the cleaning liquid is preferably 0.001 to 10 mass %, more preferably 0.005 to 8 mass %, and particularly preferably 0.01 to 5 mass %, relative to the total amount (100 mass %) of the cleaning liquid, from the viewpoint of achieving both cleaning performance and surface tension. Note that a cleaning liquid containing a high concentration of the water-soluble polymer (A) may be prepared and then appropriately diluted before use.

[0044] <Water> The cleaning solution contains water as a medium for dissolving the water-soluble polymer (A). The type of water is not particularly limited, but it is preferable to use pure water, ultrapure water, ion-exchanged water, etc., taking into consideration the effects on other components, prevention of impurity contamination, and effects on pH, etc.

[0045] <Reducing Compound (B)> The present cleaning solution may further contain a reducing compound (B). By using the present cleaning solution in combination with the water-soluble polymer (A) and the reducing compound (B), corrosion of the substrate and metal wiring is significantly suppressed. The reducing compound (B) is, for example, cerium (CeO ４ ) with water-soluble Ce ３＋ By reducing the cerium compound-containing particles to the above-mentioned compound, the particles can be easily removed from the surface to be cleaned, improving the cleaning effect. The reducing compound (B) can be appropriately selected from compounds that have a reducing effect on the cerium compound-containing particles. As the reducing compound (B), one or more compounds selected from the group consisting of gallic acid or a salt thereof, a gallic acid ester, ascorbic acid, uric acid, diphosphorous acid, and oxalic acid are preferred.

[0046] When the reducing compound (B) is used, the content of the reducing compound in the cleaning solution is preferably 0.001 to 10 mass %, more preferably 0.005 to 8 mass %, and particularly preferably 0.01 to 5 mass %, based on the total amount of the cleaning solution.

[0047] <Acidic Compound (C)> The present cleaning solution may further contain an acidic compound (C) other than the water-soluble polymer (A) and the reducing compound (B). The acidic compound (C) may be a compound used for adjusting the pH or having a function as a complexing agent, for example.

[0048] As the acidic compound (C), either an organic acid or an inorganic acid can be suitably used. From the viewpoint of further improving the cleaning effect of the cleaning liquid, the acidic compound (C) preferably includes an organic compound having one or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less, and one or more selected from sulfuric acid, nitric acid, and phosphoric acid. The hydroxyl group is preferably a phenolic hydroxyl group.

[0049] Further, examples of the acidic compound (C) having the function of a complexing agent include organic compounds having two or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less. The complexing agent can be appropriately selected from those that form complexes with the metal components in the abrasive grains (cerium compound-containing particles) and the metal components in the residues derived from the substrate generated by polishing. Specific examples of the complexing agent include tetramethylethylenediamine (TMEDA), ethylenediaminetetraacetic acid (EDTA), N-hydroxyethylethylenediaminetriacetic acid (NHEDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DPTA), ethanol diglycinate, citric acid, malic acid, gluconic acid, oxalic acid, phosphoric acid, tartaric acid, malonic acid, succinic acid, dimercaptosuccinic acid, glutaric acid, maleic acid, phthalic acid, fumaric acid, lactic acid, 2-hydroxyisobutyric acid, quinic acid, gluconic acid, lactobionic acid, phosphonoacetic acid, 3-phosphonopropionic acid, methyldiphosphonic acid, and benzophenone. Examples thereof include ammonium salts of 1,2-propanediaminepentamethylenephosphonic acid, ...

[0050] When the acidic compound (C) is used, the content of the acidic compound (C) in the cleaning liquid is preferably 0.001 to 10 mass %, more preferably 0.005 to 8 mass %, and particularly preferably 0.01 to 5 mass %, based on the total amount of the cleaning liquid.

[0051] In the cleaning solution, the water-soluble polymer (A), reducing compound (B), and acidic compound (C) can be independently combined with the reducing compound (B) and the acidic compound (C) as long as the cleaning solution contains the water-soluble polymer (A). When metal wiring is present as the cleaning target, a cleaning solution containing at least the water-soluble polymer (A) and the reducing compound (B) is preferred. When the pH is lowered while the content of the water-soluble polymer (A) is reduced, a cleaning solution containing at least the water-soluble polymer (A) and the acidic compound (C) is preferred.

[0052] <Preservatives> The cleaning solution may contain a preservative. A cleaning solution containing a preservative inhibits deterioration in quality due to microorganisms and the like, and provides better cleaning effects. Preservatives can be appropriately selected from known preservatives, but heterocyclic aromatic compounds are preferred in terms of further improving cleaning performance. Examples of heterocyclic compounds include imidazole compounds, pyrazole compounds, thiazole compounds, and triazole compounds. Examples of imidazole compounds include imidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole. Examples of pyrazole compounds include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole. Examples of thiazole compounds include benzisothiazoline, isothiazolin, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-(thiocyanomethylthio)benzthiazole, 2-mercaptobenzthiazole, and 3-allyloxy-1,2-benzisothiazole-1,1-oxide. Examples of triazole compounds include 1H-benzotriazole, 4-methyl-1H-benzotriazole, and 5-methyl-1H-benzotriazole. When a preservative is used, the content of the preservative in the cleaning solution is preferably 0.00001 to 0.1% by mass, more preferably 0.00005 to 0.05% by mass, and particularly preferably 0.0001 to 0.01% by mass, based on the total amount of the cleaning solution.

[0053] <Basic Compound> The present cleaning solution may contain a basic compound. The basic compound is used for purposes such as pH adjustment. Examples of basic compounds include monoethanolamine (MEA), diethanolamine, triethanolamine (TMA), morpholine, isopropylamine, hydroxyamine, diisopropanolamine, diglycolamine, triethylamine, N-methylmorpholine, methylethanolamine, N-aminopropylmorpholine, and 3-amino-propanol, tetramethylammonium hydroxide (TMAH), ammonium hydroxide, tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), tributylmethylammonium hydroxide (TBMAH), benzyltrimethylammonium hydroxide (BTMAH), choline, choline hydroxide, ethyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, diethyldimethylammonium hydroxide, and combinations thereof. Among these, ammonium hydroxide, choline, monoethanolamine, hydroxyamine, or triethanolamine is preferred as the basic compound.

[0054] <Water-soluble organic solvent> The cleaning solution may contain a water-soluble organic solvent, such as, but not limited to, propylene glycol (PG), glycol ether, aprotic solvents such as N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAC), sulfolane, dimethylformamide (DMF), and combinations thereof.

[0055] <Surfactant> The present cleaning solution may contain a surfactant. However, in order to ensure that the surface tension of the cleaning solution is 68 mN / m or more, it is preferable that the amount of surfactant is small. Specifically, the content of surfactant is preferably 0.01% by mass or less, more preferably 0.001% by mass or less, based on the total amount of the cleaning solution, and particularly preferably substantially free. Note that "substantially free" means that the content is 0.0001% by mass or less, based on the total amount of the cleaning solution. Examples of surfactants include salts containing suitable hydrophobic properties such as alkyl carboxylates, alkyl polyacrylates, alkyl sulfates, alkyl phosphates, alkyl bicarboxylates, alkyl bisulfates, alkyl biphosphates, substituted aryl carboxylates, substituted aryl sulfates, substituted aryl phosphates, substituted aryl bicarboxylates, substituted aryl bisulfates, and substituted aryl biphosphates, long-chain alcohols, ethoxylated alcohols, ethoxylated acetylenic diol surfactants, polyethylene glycol alkyl ethers, propylene glycol alkyl ethers, glucoside alkyl ethers, polyethylene glycol octylphenyl ethers, polyethylene glycol alkylphenyl ethers, glycerol alkyl esters, polyoxyethylene glycol sorbitone alkyl esters, sorbitone alkyl esters, cocamide diethanolamine dodecyl dimethylamine oxide, block copolymers of polyethylene glycol and polypropylene glycol, and polyethoxylated tallow amine.

[0056] <Inorganic Acid Containing Fluorine Atoms> The cleaning solution may contain an inorganic acid containing fluorine atoms. On the other hand, inorganic acids containing fluorine atoms may etch the substrate or metal wiring formed on the substrate. Therefore, from the viewpoint of suppressing damage to the surface to be cleaned, it is preferable that the amount of inorganic acid containing fluorine atoms is small. Specifically, the content of inorganic acid containing fluorine atoms in the cleaning solution is preferably 5 mM or less, more preferably 1 mM or less, even more preferably 0.1 mM or less, and particularly preferably substantially none. Examples of inorganic acids containing fluorine atoms include hydrofluoric acid, hexafluorosilicic acid, tetrafluoroboric acid, and salts thereof.

[0057] <Uses of the Cleaning Solution> The cleaning solution can be suitably used as a cleaning solution for removing abrasive grains (cerium compound-containing particles) from a surface to be cleaned, and can also suitably remove organic components such as polymers contained in the abrasive. Examples of surfaces to be cleaned include exposed surfaces (surfaces) of semiconductor substrates, and the exposed surfaces may include silicon dioxide and / or silicon nitride. The surface to be cleaned may be an exposed surface that has been polished using an abrasive containing abrasive grains. Furthermore, since the cleaning solution can suppress metal oxidation, it can also be suitably used for cleaning semiconductor substrates having exposed surfaces that include metal wiring. Furthermore, the cleaning solution can be suitably used for cleaning fine cerium compound-containing particles, and has excellent cleaning effects even for particles with an average particle diameter of 300 nm or less. The cleaning solution is particularly effective for cleaning semiconductor substrates that have undergone CMP processing using an abrasive containing cerium compound-containing particles as abrasive grains, and which include exposed surfaces with exposed oxide films, nitride films, etc., and exposed metal wiring. Cerium particles adsorbed or bonded to oxide films, etc. remain on the exposed surface, but this cleaning solution can effectively remove these particles. In addition, since this cleaning solution has good foam removal properties, it is suitable for cleaning brushes used in CMP processes to clean semiconductor substrates, and can clean the brushes in a short time.

[0058] [Cleaning Method] The cleaning method of the present disclosure includes cleaning a surface to be cleaned, to which a cerium compound has adhered, using the cleaning solution. Specific examples include scrub cleaning, in which the cleaning solution is supplied to a surface to be cleaned, such as a semiconductor substrate, while a cleaning member such as a pad or brush is physically brought into contact with the surface to be cleaned to remove cerium compound-containing particles, immersion cleaning, in which an object to be cleaned, including the surface to be cleaned, is immersed in the cleaning solution, spin-drop cleaning, in which the cleaning solution is dropped onto the rotating object, and spray cleaning, in which the cleaning solution is sprayed. In immersion cleaning, the cleaning solution may be subjected to ultrasonic treatment. The cleaning process may be performed once or twice or more times.

[0059] The temperature of the cleaning solution may be adjusted appropriately taking into consideration the heat resistance of the object to be cleaned, etc. The temperature of the cleaning solution may be adjusted appropriately within the range of, for example, 10 to 60° C., and preferably 15 to 50° C. The cleaning time may be adjusted appropriately within the range of 10 seconds to 5 minutes, and preferably 20 seconds to 3 minutes.

[0060] In this cleaning method, after cleaning with the cleaning solution, further cleaning with water or the like may be carried out as necessary, and drying may also be carried out as necessary.

[0061] The present disclosure further provides a semiconductor element obtained by the above cleaning method, which has a clean surface with few abrasive grains or polishing residues.

[0062] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, room temperature is 20 to 25°C. Examples 1 to 11, 14 to 35, and 38 are examples, and Examples 12 to 13 and 36 to 37 are comparative examples.

[0063] [Method for measuring pH and surface tension] (pH) While stirring with a magnetic stirrer, the pH of the cleaning solution was measured using a commercially available pH meter. The pH meter used was a pH meter "F-2000PI-S" manufactured by Horiba, Ltd., and a Tou pH electrode "9615S-10D."

[0064] (Surface tension of aqueous solution of water-soluble polymer (A)) The surface tension of a 0.1% by mass aqueous solution of the water-soluble polymer (A) described below was measured using a contact angle meter "DM0-502" manufactured by Kyowa Interface Science Co., Ltd., using a pendant drop method, with a drop volume of 5 μL. The measured value was calculated using the ds / de method. The surface tension of each aqueous solution of water-soluble polymer (A) is shown in Table 1.

[0065] [Materials] The materials used in each example are as follows. <Water-soluble polymer (A)> A-1: ​​Poly(4-styrenesulfonic acid). Mw is 75,000. A-2: Poly(4-styrenesulfonic acid) ammonium salt. Mw is 75,000. A-3: Naphthalenesulfonic acid formalin condensate. Mw is 25,000. A-4: Naphthalenesulfonic acid formalin condensate ethanolamine salt. Mw is 25,000. A-5: Poly(2-acrylamido-2-methyl-1-propanesulfonic acid). Mw is 2,000,000. A-6: Fluorinated sulfonic acid polymer (tetrafluoroethylene (-CF ２ CF ２ -) structure and SO ３ H group fluoroalkylene (-CF ２ CF (OCF ２ CF (CF ３ ) OCF ２ CF ２ SO ３ A binary water-soluble fluorocopolymer containing X-1: dodecylbenzenesulfonic acid. The concentration of acidic groups per unit mass is 1.40 mmol / g. <Other water-soluble polymers> X-1: dodecylbenzenesulfonic acid <Reducing compounds (B)> B-1: gallic acid B-2: pyrogallol B-3: ascorbic acid B-4: hydroquinone <Acidic compounds (C)> C-1: nitric acid (0.1 M) C-2: 1-hydroxyethylidene-1,1-diphosphonic acid C-3: citric acid C-4: tartaric acid C-5: phosphonoacetic acid

[0066]

[0067] [Examples 1 to 13: Evaluation of Cleaning and Foaming Properties] The cleaning properties of the cleaning solutions of Examples 1 to 13 described below were evaluated using the following method. <Cleanability: Performance in Removing Cerium Oxide and Organic Components> (Preparation of Substrate) A 5 cm square, 1 mm thick quartz glass plate was prepared as the substrate to be polished. A commercially available slurry-like abrasive (polishing slurry) containing cerium oxide particles with an average particle size of 300 nm or less, organic components such as polymers, surfactants, and water was prepared. One surface of the quartz glass plate was polished for 30 seconds using a commercially available CMP device and the abrasive. A "FAM12B" manufactured by SpeedFam was used as the CMP device. A hard urethane pad was used as the polishing pad. The detailed conditions were 5 minutes of pre-polishing dressing, 5 minutes of brushing, a polishing pressure of 144 g / rpm, and 5 minutes of running chemical solution at 30 cc per minute. Polishing was performed under the above conditions, rinsed several times with pure water, and then submerged and stored to obtain ceria-contaminated substrates. (Post-cleaning of polished substrates) The obtained ceria-contaminated substrates were subjected to uniaxial PVA sponge cleaning (300 rpm, cleaning speed 12.5 mm / sec, cleaning process using 5 mL of cleaning solution, twice per substrate). After rinsing several times with pure water, the substrates were dried to obtain cleaned substrates. The polished substrates that had undergone the above process are referred to as "polished substrates after post-cleaning." (Evaluation of the amount of residual cerium oxide after post-cleaning and cerium oxide removal performance) For the polished substrates after post-cleaning, the amount of ceria contaminant particles remaining on the substrate was counted using a particle inspection device (LODAS-CI8 manufactured by LAZIN). The cerium oxide removal performance was evaluated according to the following criteria: A (Good): Particle count after post-cleaning was 800 or less. B (Fair): Particle count after post-cleaning was 1,200 or less. C (Poor): Particle count after post-cleaning was more than 1,200. <Foaming ability: Rossmiles foaming height> 50 mL of the cleaning solution was placed in the bottom of a glass tube with a diameter of 50 mm, and a fixed amount (200 mL) of the cleaning solution was dropped from the top of the glass tube over 30 seconds. The height (mm) of the resulting foam was measured 30 seconds after the drop to measure the foaming power.

[0068] Example 1 At room temperature (25° C.), 0.01 g of A-1 was added to 100 g of ultrapure water and mixed with stirring to prepare the cleaning solution of Example 1. The blending composition and evaluation results are shown in Table 2.

[0069] (Examples 2 to 13) Each cleaning liquid was prepared in the same manner as in Example 1, except that the blending compositions were changed to those shown in Table 2. The blending compositions and evaluation results are shown in Table 2.

[0070]

[0071] [Examples 14-38: Evaluation of Cleaning and Corrosion Prevention] For the cleaning solutions of Examples 14-38 described below, evaluation of their cleaning properties and corrosion prevention properties was performed. The cleaning properties were evaluated using the same method as in Examples 1-13. <Corrosion Prevention: Anti-Corrosion Properties Against Copper> A silicon wafer piece coated with a Cu film was immersed in the cleaning solution, and the changes in Cu film thickness and surface shape after heating were observed. (Preparation of Test Substrate Pieces) A ​​2 cm x 4 cm square Cu film wafer piece was prepared, and the Cu film thickness was measured in advance using a resistance meter (VR300DEC, manufactured by Kokusai Electric Semiconductor Services Co., Ltd.). (Test Method) 10 mL of the cleaning solution was placed in a vinyl bag, and the Cu film wafer piece was immersed therein and heated in a constant temperature bath at 60°C for 60 minutes. After the test, the substrate was rinsed with ultrapure water, rinsed with isopropanol, and dried to obtain a test substrate. (Evaluation of the amount of residual cerium oxide after post-cleaning and cerium oxide removal performance) The corrosiveness of the copper film by the cleaning solution was evaluated by measuring the thickness of the copper film on the substrate after the test in the same manner and determining the difference. Furthermore, the shape of the copper film surface was observed using an optical microscope and evaluated according to the following criteria: A (Good): Almost no change was observed in the shape of the copper film. B (Fair): Slight discoloration or an uneven structure was observed on the copper film surface. C (Poor): Significant discoloration and change in shape were observed. <Elution: Elution of copper in the cleaning solution> (Preparation of test substrate pieces) Wafers with a Cu film formed on them were cut into 2 cm x 4 cm squares to prepare wafer pieces. (Test method) 12 mL of the cleaning solution was placed in a vinyl bag, and the above-mentioned Cu film wafer pieces were immersed in the bag and kept in a constant temperature bath at 25°C for 10 minutes. The Cu concentration in the cleaning solution after the test was quantified (ppm) by ICP emission spectrometry (Shimadzu Corporation, ICPE-9800).

[0072] (Examples 14 to 38) Each cleaning liquid was prepared in the same manner as in Example 1, except that the blending compositions were changed to those shown in Tables 3 and 4. The blending compositions and evaluation results are shown in Tables 3 and 4.

[0073]

[0074]

[0075] [Summary of Results] As shown in Tables 2 to 4, the cleaning solutions of Examples 1 to 11, 14 to 35, and 38, which contained a water-soluble polymer (a1) having sulfonic acid and a water-soluble polymer (A) having sulfonic acid and a surface tension of 68 mN / m or more at a concentration of 0.1% by mass, were shown to have excellent performance in removing cerium compound-containing particles while suppressing foaming. Furthermore, as shown in Tables 3 and 4, the cleaning solutions of Examples 14 to 34, which contained B-1 to B-3 as reducing compounds and the water-soluble polymer (A), were shown to have excellent performance in removing cerium compound-containing particles while suppressing corrosion of metal wiring.

[0076] The cleaning solution of the present disclosure is useful as a cleaning solution used in the manufacturing process of substrates for semiconductor elements, and makes it possible to shorten the cleaning process of substrates to which cerium compound-containing particles are attached and to improve the reliability of the resulting semiconductor elements, thereby improving the productivity of semiconductor elements.

[0077] This application claims priority based on Japanese Patent Application No. 2023-199775, filed November 27, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A cleaning solution for removing cerium compounds, comprising: a water-soluble polymer (A) including a water-soluble polymer (a1) having a sulfonic acid group; and water; a pH of 7 or less; and a surface tension of a 0.1% by mass aqueous solution of the water-soluble polymer (A) measured by a pendant drop method at 22°C of 68 mN / m or more.

2. The cleaning solution according to claim 1, wherein the water-soluble polymer (a1) having a sulfonic acid group has one or more repeating units selected from aromatic sulfonic acids, perfluoroalkylsulfonic acids, and salts thereof.

3. The cleaning solution according to claim 1, wherein the ratio (Nc / Ns) of the number of carbon atoms (Nc) excluding counter cations of sulfonic acid contained in a repeating unit having at least one sulfonic acid group, which is contained in the water-soluble polymer (a1) having a sulfonic acid group, to the total number (Ns) of sulfonic acid and its salts, is 7 to 15.

4. The cleaning solution according to claim 1, further comprising a reducing compound (B).

5. The cleaning solution according to claim 4, wherein the reducing compound (B) comprises one or more compounds selected from the group consisting of gallic acid, gallic acid esters, pyrogallol, ascorbic acid, uric acid, diphosphorous acid, and oxalic acid.

6. The cleaning solution according to claim 1, further comprising an acidic compound (C) other than the water-soluble polymer (A) and the reducing compound (B).

7. The cleaning solution according to claim 6, wherein the acidic compound (C) comprises an organic compound having one or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less, and one or more selected from sulfuric acid, nitric acid, and phosphoric acid.

8. The cleaning solution according to claim 6, wherein the acidic compound (C) contains an organic compound having two or more substituents selected from a carboxyl group, a phosphoryl group, a sulfonic acid group, and a hydroxyl group in the molecule and having a molecular weight of 1,000 g / mol or less.

9. The cleaning solution according to claim 1, wherein the pH is from 1 to 5.

10. The cleaning solution of claim 1 further comprising a preservative.

11. The cleaning solution according to claim 1, wherein the water-soluble polymer (A) is contained in an amount of 0.001 to 10 mass %.

12. The cleaning solution according to claim 4, wherein the reducing compound (B) is contained in an amount of 0.001 to 10 mass %.

13. The cleaning solution according to claim 6, wherein the acidic compound (C) is contained in an amount of 0.001 to 10 mass %.

14. The cleaning solution according to claim 1, having a Ross Miles foam height at 25°C of 30 mm or less.

15. The cleaning solution according to claim 1, in which the amount of Cu eluted is 3.0 ppm or less when a silicon substrate having a Cu film formed thereon is immersed in 12 mL of an aqueous solution containing the water-soluble polymer (A) at 25° C. for 10 minutes.

16. The cleaning solution according to any one of claims 1 to 15, which is used for cleaning a semiconductor substrate having a cerium compound attached thereto.

17. The cleaning solution of claim 16, wherein at least a portion of the semiconductor substrate has an exposed surface including metal wiring.

18. The cleaning solution according to any one of claims 1 to 15, which is for cleaning a brush used for cleaning a semiconductor substrate, the brush having a cerium compound attached thereto.

19. The cleaning solution according to any one of claims 1 to 15, which is used for cleaning an object whose surface has been polished with an abrasive containing particles containing a cerium compound.

20. The cleaning solution according to claim 19, wherein the average particle size of the cerium compound-containing particles is 300 nm or less.

21. A cleaning method comprising cleaning a surface to which a cerium compound has adhered with the cleaning solution according to any one of claims 1 to 15.

22. A method for manufacturing a semiconductor device, comprising: preparing a semiconductor substrate polished with an abrasive containing particles containing a cerium compound; and cleaning the polished surface of the semiconductor substrate with the cleaning solution according to any one of claims 1 to 15.

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