Surface treatment composition, surface treatment method, and method for producing semiconductor substrate

Abstract

This invention provides a method for effectively removing residues remaining on the surface of a polished object. This invention also provides a surface treatment composition comprising components (A) and (B) below, and having a pH value of 8.0 or higher. (A) Composition: A polymer containing structural units of quaternary nitrogen-containing onium salts or structural units of the following structure (X); (B) Components: Buffer represented by the formula: R-COO-NH4+.

Description

Technical Field

[0001] This invention relates to a surface treatment composition, a surface treatment method, and a method for manufacturing a semiconductor substrate. Prior Technology

[0002] In recent years, with the increasing use of multilayer wiring on semiconductor substrates, the industry has adopted chemical mechanical polishing (CMP) technology during device manufacturing. This technology physically grinds semiconductor substrates to achieve planarization. CMP uses a polishing composition (slurry) containing abrasive particles such as silicon dioxide, aluminum oxide, and cerium oxide, as well as etching inhibitors and surfactants, to planarize the surface of the object being polished, such as a semiconductor substrate. The object being polished can be wiring, connectors, etc., containing silicon, polycrystalline silicon, silicon oxide, silicon nitride, or metals.

[0003] After the CMP process, a large number of impurities (also known as foreign matter or residue) remain on the surface of the semiconductor substrate. These impurities include: abrasive grains, metals, corrosion inhibitors, surfactants, and other organic matter from the polishing composition used in CMP; silicon-containing materials that are the objects being polished; silicon-containing materials or metals generated by polishing metal wiring or plugs; and organic matter such as pad debris generated from various gaskets.

[0004] If the surface of the semiconductor substrate is contaminated by such impurities, it will adversely affect the electrical properties of the semiconductor, and the reliability of the device may be reduced. Therefore, it is ideal to introduce a cleaning step after the CMP step to remove such impurities from the surface of the semiconductor substrate.

[0005] As a cleaning composition, for example, Japanese Patent Application Publication No. 2020-90625 discloses a cleaning agent composition containing: a polymer (salt) having a specific structural unit (component A); and an amine-containing compound other than component A containing at least one amine group and having one to ten nitrogen atoms (component B). This cleaning agent composition is disclosed to have excellent cleaning properties and can improve the smoothness of the substrate surface after cleaning. Summary of the Invention

[0006] However, the technology disclosed in Japanese Patent Application Publication No. 2020-90625 has the problem that foreign matter (residue) cannot be adequately removed during the cleaning of the ground object.

[0007] Therefore, the present invention was made in view of the above circumstances, and its object is to provide a method for effectively removing residues remaining on the surface of a polished object.

[0008] The inventors have conducted intensive research to solve the aforementioned problems. As a result, they discovered that an alkaline surface treatment composition can solve these problems, thereby completing the present invention. This alkaline surface treatment composition comprises a polymer having structural units with a specific structure and an ammonium monocarboxylate that acts as a buffer.

[0009] That is, the above objective is achieved using a surface treatment composition comprising component (A) and component (B) and having a pH value of 8.0 or higher: (A) Composition: A polymer containing structural units of quaternary nitrogen-containing onium salts or structural units of the following structure (X):

[0010] [Chemistry 1]

[0011] In the above structure (X), R 31 to R 34 independently represent hydrogen atoms or straight-chain or branched alkyl groups having 1 or more but less than 10 carbon atoms; (B) Components: Buffer represented by the formula: R-COO-NH4+ (R is a straight-chain or branched alkyl or phenyl group with 1 or more carbon atoms and less than 10 carbon atoms).

[0012] This invention provides a surface treatment composition comprising components (A) and (B) below, and having a pH value of 8.0 or higher: (A) Composition: A polymer containing structural units of quaternary nitrogen-containing onium salts or structural units of the following structure (X):

[0013] [Chemistry 2]

[0014] In the above structure (X), R 31 to R 34 independently represent hydrogen atoms or straight-chain or branched alkyl groups having 1 or more but less than 10 carbon atoms; (B) Composition: Buffer represented by the formula: R-COO-NH4+ (R is a straight-chain or branched alkyl or phenyl group with 1 or more but less than 10 carbon atoms). According to the present invention, a method is provided that can sufficiently remove residues remaining on the surface of a polished workpiece. That is, according to this surface treatment composition of the present invention, residues (e.g., abrasive particle residues, organic residues) remaining on the surface of a polished workpiece (especially a polished silicon nitride substrate) can be sufficiently removed. Furthermore, the etching rate of a polished workpiece containing polycrystalline silicon can be suppressed to a low level.

[0015] Regarding the mechanism by which this structure can remove residue from the surface of the polished object and further suppress the etching rate of the polished object containing polysilicon to a lower level, the inventors speculate as follows.

[0016] That is, the surface treatment composition contains specific components (A) and (B). Component (A) does not exhibit a pKa in water and is positively charged. Therefore, regardless of pH, the zeta potential of the polished object (especially polished silicon nitride substrate), abrasive residues, and organic residues (e.g., padding shavings, polymers) is controlled to be positive, and by electrostatic repulsion, residue adsorption on the polished object can be suppressed and prevented. Furthermore, component (A) increases the wettability of the polished object surface, facilitating the formation of a water molecule film on the surface. Therefore, not only is the adhesion of hydrophobic organic residues to the polished object surface suppressed, but the re-adhesion of organic residues is also prevented. Therefore, the surface treatment composition according to the present invention can efficiently remove residues. Also, typically, before the cleaning step (surface treatment, rinsing and polishing), the semiconductor substrate surface is polished using an alkaline slurry (polishing slurry) in a CMP step. When using a surface treatment composition to clean (rinse and polish) such a polished semiconductor substrate (the polished object), the pH value of the surface treatment composition will rise due to the alkaline polishing slurry. As a result, residue adhesion is induced due to changes in the zeta potential of the residue, or the etching rate of the polished object containing polycrystalline silicon increases. However, by the presence of component (B), the rise in pH value of the surface treatment composition during cleaning (rinsing and polishing) can be suppressed. Therefore, the zeta potential of the polished object (especially the polished silicon nitride substrate), abrasive residue, organic residue (e.g., padding, polymer), etc., is controlled to an optimal state (positive), and the adsorption of residue to the polished object can be suppressed and prevented by electrostatic repulsion. Therefore, the surface treatment composition according to the present invention can remove residues efficiently. Furthermore, under alkaline conditions, the etching rate of the polished object containing polycrystalline silicon changes significantly. However, due to the presence of component (B), the pH value of the surface treatment composition during cleaning (rinsing and polishing) changes less (it is less affected by alkaline polishing slurry). Therefore, the etching rate of polished objects containing polycrystalline silicon can be suppressed to a lower level.

[0017] Furthermore, the above mechanism is based on speculation, and the present invention is not limited by the above mechanism in any way. Implementation

[0018] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the patent application. Throughout this specification, unless otherwise specified, singular expressions should be understood to include the concept of their plural forms as well. Therefore, singular articles (e.g., "a," "an," "the," etc. in the case of English) should be understood to include the concept of their plural forms as well, unless otherwise specified. Furthermore, the terms used in this specification, unless specifically mentioned, should be understood to be used in their commonly used meaning in the field. Therefore, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention pertains. In case of conflict, this specification (including definitions) takes precedence. Unless otherwise specified in this instruction manual, the operation and physical properties are measured at room temperature (above 20°C and below 25°C) and relative humidity (above 40%RH and below 50%RH).

[0019] <Residue> In this specification, residue refers to foreign matter adhering to the surface of the object being ground. Examples of residue are not particularly limited, but may include: residue originating from the object being ground, organic residue described below, particulate residue (abrasive particle residue) originating from the abrasive particles contained in the grinding composition, residue containing components other than particulate residue and organic residue, mixtures of particulate residue and organic residue, and other residues.

[0020] The total residue count, regardless of type, represents the total number of all residues. The total residue count can be determined using a wafer defect inspection device. Alternatively, the residue count represents the total number of a specific type of residue. Details of the method for determining the residue count are described in the following examples.

[0021] In this specification, organic residue refers to foreign matter adhering to the surface of the polished object (surface-treated object), including organic compounds such as low-molecular-weight organic compounds or high-molecular-weight organic compounds or organic salts.

[0022] Organic residues adhering to the object being ground can be exemplified by: pad debris generated from the pads used in the grinding or rinsing grinding steps, or components of additives contained in the grinding composition used in the grinding step or the surface treatment composition used in the rinsing grinding step.

[0023] Furthermore, since organic residues differ significantly in color and shape from other foreign matter, they can be visually determined using SEM (Scanning Electron Microscope) to ascertain whether the foreign matter is organic residue. Additionally, the determination of whether a foreign matter is organic residue can also be made using elemental analysis with an energy dispersive X-ray (EDX) device, if necessary. The number of organic residues can be determined using wafer defect inspection equipment and SEM or EDX elemental analysis.

[0024] <Object that has been ground> In this specification, "polished object" refers to the object that has been polished in the polishing step. There are no particular limitations on the polishing step, but CMP is preferred.

[0025] The materials contained in the polishing object of this invention are not particularly limited, and examples include: silicon oxide, silicon nitride (SiN), silicon carbonitride (SiCN), and other silicon-containing materials, polysilicon, amorphous silicon, silicon materials doped with impurities, metal monomers, alloys, metal nitrides, compound semiconductors such as SiGe, etc. Among these, it is preferred to include at least one of silicon nitride, silicon oxide, and polysilicon. That is, the polishing object (e.g., a semiconductor substrate before polishing) contains at least one material selected from the group consisting of silicon nitride, silicon oxide, and polysilicon.

[0026] Examples of films containing silicon oxide include: TEOS (Tetraethyl Orthosilicate) type silicon oxide films (hereinafter also simply referred to as "TEOS films") formed using tetraethyl orthosilicate as a precursor; HDP (High Density Plusma) films; USG (Undoped Silicate Glass) films; PSG (Phosphorus Silicate Glass) films; BPSG (Boron-Phospho Silicate Glass) films; and RTO (Rapid Thermal Oxidation) films. The material contained in the object being ground can be a single type or a combination of two or more materials.

[0027] The object to be ground is preferably a ground semiconductor substrate, and more preferably a ground semiconductor substrate after the CMP step. The reason is that, since residues may damage semiconductor devices, when the object to be ground is a ground semiconductor substrate, the cleaning step of the semiconductor substrate needs to remove as much residue as possible.

[0028] Furthermore, the surface treatment composition of one aspect of the present invention can reduce surface residue even on a polished object containing both hydrophilic and hydrophobic materials. Here, hydrophilic materials refer to materials with a water contact angle of less than 50°, and hydrophobic materials refer to materials with a water contact angle of 50° or more. Moreover, the water contact angle is measured using a DropMaster (DMo-501) contact angle meter manufactured by Kyowa Interface Science Co., Ltd.

[0029] Specific examples of hydrophilic materials include silicon oxide, silicon nitride, silicon oxynitride, tungsten, titanium nitride, tantalum nitride, and boron-containing silicon. These hydrophilic materials can be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the hydrophilic material is silicon oxide. According to a preferred embodiment of the present invention, the hydrophilic material is silicon nitride. Furthermore, specific examples of hydrophobic materials include polycrystalline silicon, monocrystalline silicon, amorphous silicon, and carbon-containing silicon. These hydrophobic materials can be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the hydrophobic material is polycrystalline silicon.

[0030] That is, according to a preferred embodiment of the present invention, the hydrophilic material is silicon oxide and the hydrophobic material is polycrystalline silicon. Also, according to a preferred embodiment of the present invention, the hydrophilic material is silicon nitride and the hydrophobic material is polycrystalline silicon.

[0031] <Surface Treatment Composition> The surface treatment composition of the present invention comprises the following components (A) and (B), and has a pH value of 8.0 or higher: (A) Composition: A polymer containing structural units of quaternary nitrogen-containing onium salts or structural units of the following structure (X):

[0032] [Chemistry 3]

[0033] In the above structure (X), R 31 to R 34 independently represent hydrogen atoms or straight-chain or branched alkyl groups having 1 or more but less than 10 carbon atoms; (B) Components: Buffer represented by the formula: R-COO-NH4+ (R is a straight-chain or branched alkyl or phenyl group with 1 or more carbon atoms and less than 10 carbon atoms).

[0034] The surface treatment composition of the present invention is used to reduce residue on the surface of a polished object. Furthermore, the surface treatment composition of the present invention is used to suppress the etching rate of a polished object containing polycrystalline silicon to a lower level.

[0035] In this specification, the polymer containing a quaternary nitrogen-containing onium salt structural unit or the structural unit of structure (X) described above, which is component (A), is also referred to as "the polymer of the present invention" or "polymer". Furthermore, the buffer represented by the formula R-COO-NH4+ (where R is a straight-chain or branched alkyl or phenyl group with 1 or more carbon atoms) which is component (B), is also referred to as "the buffer of the present invention", "the monocarboxylic acid ammonium of the present invention", or "monocarboxylic acid ammonium".

[0036] [(A)Component] (A) is a polymer comprising at least one of a structural unit having a quaternary nitrogen-containing onium salt and a structural unit of structure (X) described above. That is, the polymer as component (A) comprises a structural unit having a quaternary nitrogen-containing onium salt, a structural unit of structure (X) described above, or both a structural unit having a quaternary nitrogen-containing onium salt and a structural unit of structure (X) described above. The polymer of the present invention is cationic (cationic polymer).

[0037] In the above structure (X), R 31 to R 34 each independently represent a hydrogen atom or a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms. Here, R 31 to R 34 may be the same or different. As an alkyl group, there are no particular limitations, and examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, dibutyl, tributyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tripentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, trioctyl, 2-ethyloctyl, 2-butyloctyl, 3,7-dimethyloctyl, n-nonyl, n-decyl, etc. Among them, R 31 to R 34 are preferably hydrogen atoms or straight-chain or branched alkyl groups having 1 or more but less than 3 carbon atoms, more preferably hydrogen atoms, methyl or ethyl, and even more preferably hydrogen atoms.

[0038] A polymer having the structural unit of structure (X) described above is sufficient to have only structure (X). In addition to structure (X), it may further contain structural units such as those with methylene amino groups (-CH₂NH₃), ethylamino groups (-CH₂CH₂NH₃), trimethylene amino groups (-CH₂CH₂CH₂NH₃), divalent groups derived from amidine (-NH-C(=NH)-), and divalent groups derived from guanidine (-NH-C(=NH)-NH₃). These other structural units may exist individually, or in combination of two or more.

[0039] Polymers having the structural unit of structure (X) described above can be synthesized or are commercially available. For example, polymers having the structural unit of structure (X) described above can be obtained by the condensation reaction of dicyandiamide and diethylenetriamine. Alternatively, as commercially available products, UNISENSE KHP10L (dicyandiamide-diethylenetriamine condensate) and UNISENSE KHP10P (dicyandiamide-diethylenetriamine condensate) (both manufactured by Senka Co., Ltd.) can be used.

[0040] The structural units of the quaternary nitrogen-containing onium salts constituting the polymers of component (A) are, for example, structural units derived from the following monomers, which have vinyl unsaturated groups such as acrylonitrile (H 2C=CH-C(=O)-), methacrylonitrile (H 2C=C(CH 3)-C(=O)-), acrylonitrileoxy (H 2C=CH-C(=O)-O-), methacrylonitrileoxy (H 2C=C(CH 3)-C(=O)-O-), acrylonitrileamine (H 2C=CH-C(=O)-NH-), methacrylonitrileamine (H 2C=C(CH 3)-C(=O)-NH-), vinyl (H 2C=CH-), allyl (H 2C=CHCH 2-), and quaternary nitrogen-containing onium salts (-N +(R) 2- or -N +(R) 3).

[0041] Preferably, the structural unit of the quaternary nitrogen-containing onium salt constituting the polymer (A) has at least one of the following structures (Y) and (Z). The structure (Y) may be a single type or a combination of two or more. When multiple structures (Y) exist, the structure (Y) may exist in a bulk form or an irregular form. When the polymer (A) has two or more structures (Y), the structures (Y) may be identical or different. Similarly, the structure (Z) may be a single type or a combination of two or more. When multiple structures (Z) exist, the structure (Z) may exist in a bulk form or an irregular form. When the polymer (A) has two or more structures (Z), the structures (Z) may be identical or different. Furthermore, component (A) may also have one or more structures (Y) and one or more structures (Z). []

[0042] [Chemistry 4]

[0043] In the above structure (Y), R 11 represents a hydrogen atom or a methyl group. R 12 represents a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms. R 12 is preferably a straight-chain or branched alkyl group having 2 or more but less than 6 carbon atoms, and even more preferably an ethyl (-CH 2CH 2-), a trimethylene (-CH 2CH 2CH 2-), or an propyl (-CH(CH 3)CH 2- or -CH 2CH(CH 3)-), and most preferably an ethyl.

[0044] In the above structure (Y), R13 to R15 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms. Here, R13 to R15 may be the same or different. As an alkyl group, the same alkyl group described in R31 to R34 above can be exemplified. Among them, R13 to R15 are preferably straight-chain or branched alkyl groups having 1 or more but less than 8 carbon atoms, more preferably straight-chain or branched alkyl groups having 1 or more but less than 3 carbon atoms, and even more preferably methyl or ethyl.

[0045] In the above structure (Y), X1 represents the anion portion. There are no particular restrictions on the anion portion (counter anion) as long as it can form a salt with the above-mentioned quaternary nitrogen-containing onium salt (quaternary nitrogen-containing onium cation: -N + (R 13)(R 14)(R 15)). Examples of such anions include: halides such as fluoride ions (F-), chloride ions (Cl-), bromide ions (Br-), and iodide ions (I-); bisulfite ions (HSO₄-); sulfite ions (HSO₃-); alkyl sulfate ions ((Alkyl)SO₄-: Alkyl is an alkyl group with 1 or more carbon atoms and 8 or fewer carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, dibutyl, tributyl, preferably methyl or ethyl)); sulfate ions (SO₄²⁻); nitrate ions (NO₃⁻); dihydrogen phosphate ions (H₂PO₄⁻), hydrogen phosphate ions (HPO₄²⁻), phosphate ions (PO₄³⁻); perchlorate ions (ClO₄⁻); and hydroxide ions (OH⁻). -); carboxylic acid anions such as citrate ion, acetate ion, malate ion, fumarate ion, lactate ion, glutarate ion, and maleate ion. Among these, X1 (anion portion, counter anion) is preferably a halide ion, alkyl sulfate ion, or nitrate ion, more preferably a halide ion or alkyl sulfate ion, and even more preferably a chloride ion, methyl sulfate ion (CH3SO4-), or ethyl sulfate ion (C2H5SO4-), and especially preferably a chloride ion.

[0046] In one embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the above-described structure (Y), wherein R 11 represents a hydrogen atom or a methyl group; R 12 represents a straight-chain or branched alkyl group having 2 or more but less than 6 carbon atoms; R 13 to R 15 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 8 carbon atoms; and X 1 represents an anionic portion selected from halide ions and alkyl sulfate ions. In one embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the above-described structure (Y), wherein R 11 represents a hydrogen atom or a methyl group; R 12 represents an ethyl, trimethylene, or propyl group; R 13 to R 15 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 3 carbon atoms; and X 1 represents a halide ion or an alkyl sulfate ion. In one embodiment of the present invention, the structural unit having a four-level nitrogen-containing onium salt has the above-described structure (Y), wherein R 11 represents a hydrogen atom or a methyl group; R 12 represents an ethyl group; R 13 to R 15 each independently represent a methyl group or an ethyl group; and X 1 represents a chloride ion, a methyl sulfate ion (CH 3SO 4 -) or an ethyl sulfate ion (C 2H 5SO 4 -) (especially a chloride ion).

[0047] [Chemistry 5]

[0048] In the above structure (Z), R21 and R22 independently represent a hydrogen atom, a straight-chain or branched alkyl group or a phenyl group having 1 or more but 3 or fewer carbon atoms. Here, R21 and R22 may be the same or different. As an alkyl group having 1 or more but 3 or fewer carbon atoms, there are methyl, ethyl, n-propyl, and isopropyl. Among them, R21 and R22 are preferably hydrogen atoms or alkyl groups having 1 or more but 3 or fewer carbon atoms, more preferably hydrogen atoms, methyl or ethyl, and even more preferably hydrogen atoms.

[0049] In the above structure (Z), R23 and R24 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms. Here, R23 and R24 may be the same or different. As an alkyl group, the same alkyl group described in R31 to R34 above can be exemplified. Among them, R23 and R24 are preferably straight-chain or branched alkyl groups having 1 or more but less than 8 carbon atoms, more preferably straight-chain or branched alkyl groups having 1 or more but less than 3 carbon atoms, and even more preferably methyl.

[0050] In the above structure (Z), X2 represents the anion portion. Here, the anion portion can be the same as that described in the anion portion (X1) of the above structure (Y). Among them, X2 (anion portion, counter anion) is preferably a halide ion, alkyl sulfate ion, or nitrate ion, more preferably a halide ion or alkyl sulfate ion, and even more preferably a chloride ion, methyl sulfate ion (CH3SO4-) or ethyl sulfate ion (C2H5SO4-), and especially preferably a chloride ion.

[0051] In one embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the above-described structure (Z), wherein R 21 and R 22 each independently represent a hydrogen atom or a straight-chain or branched alkyl group having 1 or more but 3 or fewer carbon atoms; R 23 and R 24 each independently represent a straight-chain or branched alkyl group having 1 or more but 8 or fewer carbon atoms; and X 2 represents an anionic portion selected from halide ions and alkyl sulfate ions. In one embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the above-described structure (Z), wherein R 21 and R 22 each independently represent a hydrogen atom, methyl, or ethyl; R 23 and R 24 each independently represent a straight-chain or branched alkyl group having 1 or more but 3 or fewer carbon atoms; and X 2 represents a halide ion (especially a chloride ion) or an alkyl sulfate ion (especially a methyl sulfate ion or an ethyl sulfate ion). In one embodiment of the present invention, the structural unit having a four-level nitrogen-containing onium salt has the above-described structure (Z), wherein R 21 and R 22 represent hydrogen atoms; R 23 and R 24 represent methyl groups; and X 2 represents chloride ions.

[0052] In a preferred embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the following structure (Z'), wherein R 21 and R 22 each independently represent a hydrogen atom or a straight-chain or branched alkyl group having 1 or more but less than 3 carbon atoms; R 23 and R 24 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 8 carbon atoms; X 2 represents an anionic portion selected from halide ions and alkyl sulfate ions, and n is an integer of 0 or more but less than 3. In a preferred embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the following structure (Z'), wherein R 21 and R 22 each independently represent a hydrogen atom, methyl or ethyl; R 23 and R 24 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 3 carbon atoms; X 2 represents a halide ion (especially a chloride ion) or an alkyl sulfate ion (especially a methyl sulfate ion or an ethyl sulfate ion), and n is 1 or 2. In a preferred embodiment of the present invention, the structural unit having a quaternary nitrogen-containing onium salt has the following structure (Z'), wherein R 21 and R 22 represent hydrogen atoms; R 23 and R 24 represent methyl groups; X 2 represents chloride ions, and n is 1.

[0053] [Chemistry 6]

[0054] Component (A) preferably comprises a polymer containing a structural unit having a quaternary nitrogen-containing onium salt. Here, component (A) may also comprise components other than a polymer having the aforementioned specific structural unit, but from the viewpoint of further improving the effect of the present invention, component (A) preferably comprises a polymer having the aforementioned specific structural unit (component (A) is a polymer having the aforementioned specific structural unit). By including component (A), residues remaining on the surface of the polished object can be removed efficiently. That is, in a preferred embodiment of the present invention, component (A) comprises a polymer containing a structural unit having a quaternary nitrogen-containing onium salt. In a more preferred embodiment of the present invention, component (A) comprises a polymer containing a structural unit having a quaternary nitrogen-containing onium salt (component (A) is a polymer containing a structural unit having a quaternary nitrogen-containing onium salt).

[0055] When component (A) comprises a polymer having a structural unit containing a quaternary nitrogen-containing onium salt, the polymer preferably has at least one of the above structures (Y) and (Z). The polymer having a structural unit containing a quaternary nitrogen-containing onium salt is more preferably having one of the above structures (Y) and (Z) (structure (Y) or (Z)).

[0056] When component (A) contains a polymer having a structural unit with a quaternary nitrogen-containing onium salt, the polymer may have a structural unit with a quaternary nitrogen-containing onium salt other than the above-mentioned structure (Y) and structure (Z), but preferably the structural unit with a quaternary nitrogen-containing onium salt is only the above-mentioned structure (Y) or the above-mentioned structure (Z), more preferably only the above-mentioned structure (Z), and even more preferably only the above-mentioned structure (Z').

[0057] That is, in a preferred embodiment of the present invention, the structural unit having a four-level nitrogen-containing onium salt is only the following structure (Y) or the following structure (Z):

[0058] [Chemistry 7]

[0059] In the above structure (Y), R11 represents a hydrogen atom or a methyl group, R12 represents a straight-chain or branched alkyl group with 1 or more but less than 10 carbon atoms, R13 to R15 each independently represent a straight-chain or branched alkyl group with 1 or more but less than 10 carbon atoms, and X1 represents an anionic portion;

[0060] [Chemistry 8]

[0061] In the above structure (Z), R 21 and R 22 independently represent hydrogen atoms, straight-chain or branched alkyl or phenyl groups with 1 or more but less than 3 carbon atoms, R 23 and R 24 independently represent straight-chain or branched alkyl groups with 1 or more but less than 10 carbon atoms, and X 2 represents an anionic part.

[0062] In a preferred embodiment of the present invention, the structural unit having a four-level nitrogen-containing onium salt is only the structure described above (Z).

[0063] In a preferred embodiment of the present invention, the structural unit having a four-level nitrogen-containing onium salt is only the following structure (Z').

[0064] [Chemistry 9]

[0065] In the above structure (Z'), R 21 and R 22 independently represent hydrogen atoms, straight-chain or branched alkyl or phenyl groups with 1 or more but less than 3 carbon atoms, R 23 and R 24 independently represent straight-chain or branched alkyl groups with 1 or more but less than 10 carbon atoms, X 2 represents the anionic part, and n is an integer of 0 or more but less than 3.

[0066] Polymers containing quaternary nitrogen-containing onium salt structural units may contain only the aforementioned structure (Y) or structure (Z), or may contain other structural units besides the aforementioned structure (Y) or structure (Z). Polymers containing quaternary nitrogen-containing onium salt structural units preferably contain other structural units besides the aforementioned structure (Y) or structure (Z), and more preferably contain other structural units besides the aforementioned structure (Z).

[0067] Examples of other structural units that can be used in the polymer of this invention include those derived from monomers such as acrylic acid, methacrylic acid, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylamide, methacrylamide, acrylmethyl diethyl betaine, methacrylamide diethyl betaine, acrylethyl dimethyl betaine, methacrylamide diethyl betaine, methoxylated polyethylene glycol acrylate, methoxylated polyethylene glycol methacrylate, methoxylated polypropylene glycol acrylate, methoxylated polypropylene glycol methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and N-vinyl-2-pyrrolidone. Other structural units may be present individually or in combination of two or more. Among these, other structural units are preferably derived from structural units of monomers selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, methacrylamide, methacrylyl ethyl dimethyl betaine, methoxy polyethylene glycol methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and N-vinyl-2-pyrrolidone; more preferably, they are derived from structural units of monomers selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, and methacrylamide; and even more preferably, they are derived from structural units of monomers selected from the group consisting of acrylic acid and methacrylic acid.

[0068] Furthermore, when the polymer of the present invention has other structural units, the composition (content) of the other structural units relative to the total number of structural units of the polymer is, for example, 1 mol% or more, preferably 5 mol% or more, and more preferably 30 mol% or more. Also, the composition (content) of the other structural units relative to the total number of structural units of the polymer is, for example, 50 mol% or less, preferably 40 mol% or less, and more preferably 30 mol% or more. When the polymer of the present invention has other structural units, the composition (content) of the other structural units relative to the total number of structural units of the polymer is, for example, 1 mol% or more and 50 mol% or less, preferably 5 mol% or more and 40 mol% or less, and more preferably 5 mol% or more and 30 mol% or less. Alternatively, when the polymer of the present invention has other structural units, the composition (content) of the other structural units relative to the total number of structural units of the polymer is, for example, 50 mol.

[0069] Polymers containing structural units with quaternary nitrogen-containing onium salts can be manufactured synthetically or are commercially available. Examples of commercially available products include: Merquat TM295 polymer (dimethyl diallyl ammonium chloride / acrylic acid copolymer, Mw=190,000), Merquat TM550 polymer (dimethyl diallyl ammonium chloride / acrylamide copolymer, Mw=1,600,000), Merquat TM100 polymer (polydimethylmethylenepiperidinium chloride) (all from Japan Lubrizol); UNISENSE FPA-100L (polydimethyl diallyl ammonium chloride (polydimethylmethylenepiperidinium chloride), Mw=less than 20,000), UNISENSE FPA-101L (polydimethyl diallyl ammonium chloride (polydimethylmethylenepiperidinium chloride)), UNISENSE... FPA-102L (polydimethyldiallylammonium chloride (polydimethylmethylenepiperidinium chloride), Mw=20,000~100,000), UNISENSE FPA-1000L (polydimethyldiallylammonium chloride (polydimethylmethylenepiperidinium chloride), Mw=100,000~500,000), UNISENSE FPA-1001L (polydimethyldiallylammonium chloride (polydimethylmethylenepiperidinium chloride)), UNISENSE FPA-1002L (polydimethyldiallylammonium chloride (polydimethylmethylenepiperidinium chloride)) (all manufactured by Senka Corporation); Plascize L-440 (methacryloylethyldimethylbetaine-methacryloylethyltrimethylammonium chloride-methoxy polyethylene glycol methacrylate copolymer), Plascize L-440W (methacrylyl ethyl dimethyl betaine-methacrylyl ethyl trimethyl ammonium chloride-methoxy polyethylene glycol methacrylate copolymer), Plascize L-450 (methacrylyl ethyl dimethyl betaine-methacrylyl ethyl trimethyl ammonium chloride-2-hydroxyethyl methacrylate copolymer), Plascize L-450W (methacrylyl ethyl dimethyl betaine-methacrylyl ethyl trimethyl ammonium chloride-2-hydroxyethyl methacrylate copolymer) (all from Mutual Chemical Industry Co., Ltd.); HC Polymer 1S(M) (vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate copolymer diethyl sulfate, Mw=500,000), HC Polymer 5W (vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate copolymer diethyl sulfate, Mw=150,000) (all from Osaka Organic Chemical Industry Co., Ltd.), etc.

[0070] In this specification, "polymer" means a polymer with a weight average molecular weight (Mw) of 1,000 or more. The weight average molecular weight (Mw) of component (A) is, for example, 5,000 or more, preferably 10,000 or more, more preferably 20,000 or more, and even more preferably over 100,000. The weight average molecular weight (Mw) of component (A) is, for example, 5,000,000 or less, preferably 3,000,000 or less, more preferably 2,000,000 or less, even more preferably 1,000,000 or less, particularly preferably 500,000 or less, and most preferably 250,000 or less. That is, in one embodiment of the present invention, the weight average molecular weight (Mw) of component (A) is 5,000 or more and 5,000,000 or less. In one embodiment of the present invention, the weight-average molecular weight (Mw) of component (A) is 10,000 or more and 3,000,000 or less. In one embodiment of the present invention, the weight-average molecular weight (Mw) of component (A) is 20,000 or more and 1,000,000 or less. In one embodiment of the present invention, the weight-average molecular weight (Mw) of component (A) is more than 100,000 and less than 500,000. In one embodiment of the present invention, the weight-average molecular weight (Mw) of component (A) is more than 100,000 and less than 250,000. In this specification, the weight-average molecular weight (Mw) of component (A) is determined according to the method described in the following examples.

[0071] (A) One ingredient may be used alone, or two or more ingredients may be used in combination.

[0072] The content of component (A) in the surface treatment composition is appropriately set according to the type of component (A) used or the desired effect. When the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (A) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably more than 0.05% by mass. Furthermore, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the upper limit of the content of component (A) in the surface treatment composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less. In one embodiment of the present invention, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (A) is 0.01% by mass or more and 1% by mass or less. In one embodiment of the present invention, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (A) is 0.05% by mass or more and 0.5% by mass or less. In one embodiment of the present invention, the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), and the content of component (A) is more than 0.05% by mass and less than 0.3% by mass. Furthermore, when the surface treatment composition contains two or more components (A), the content of component (A) means the total amount of them.

[0073] [(B) Component] In addition to component (A) described above, the surface treatment composition of this invention also includes component (B). Component (B) includes a buffer (ammonium monocarboxylate) represented by the formula: R-COO-NH4+. In this specification, "buffer" means a substance that imparts a buffering effect to the surface treatment composition (solution) in order to maintain a constant pH value.

[0074] (B) Component may also include components other than the buffer represented by the above formula: R-COO-NH 4+ (e.g., known buffers), but from the viewpoint of further improving the effect of the present invention, (B) component preferably includes the buffer represented by the above formula: R-COO-NH 4+ ((B) component is the buffer represented by the above formula: R-COO-NH 4+). By the presence of (B) component, residues remaining on the surface of the polished object can be removed efficiently. Furthermore, the etching rate of the polished object containing polycrystalline silicon can be suppressed to a lower level. That is, in the preferred embodiment of the present invention, (B) component includes the buffer represented by the above formula: R-COO-NH 4+ ((B) component is the buffer represented by the above formula: R-COO-NH 4+).

[0075] In the above formula: R-COO-NH4+, R is a straight-chain or branched alkyl or phenyl group having 1 or more but less than 10 carbon atoms. Here, alkyl groups can be exemplified as those described in R31 to R34 above. From the viewpoint of further improving the effect of the present invention, R is preferably a straight-chain or branched alkyl group having 1 or more but less than 8 carbon atoms, more preferably a straight-chain or branched alkyl group having 1 or more but less than 3 carbon atoms, and even more preferably methyl (ammonium acetate) or ethyl (ammonium propionate), especially methyl (ammonium acetate). That is, in the preferred embodiment of the present invention, the buffer is represented by the above formula: R-COO-NH4+, where R is a straight-chain or branched alkyl group having 1 or more but less than 8 carbon atoms. In a more preferred embodiment of the present invention, the buffer is represented by the above formula: R-COO-NH4+, where R is a straight-chain or branched alkyl group having 1 or more but less than 3 carbon atoms. In a further preferred embodiment of the invention, the buffer is represented by the above formula R-COO-NH4+, where R is methyl or ethyl (the buffer is ammonium acetate or ammonium propionate). In a particularly preferred embodiment of the invention, the buffer is ammonium acetate.

[0076] The content of component (B) in the surface treatment composition is appropriately set according to the type of component (B) used or the desired effect. When the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (B) is preferably 0.05% by mass or more, more preferably more than 0.1% by mass, and even more preferably 0.2% by mass or more. Furthermore, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the upper limit of the content of component (B) in the surface treatment composition is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less. In one embodiment of the present invention, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (B) is 0.05% by mass or more and 2% by mass or less. In one embodiment of the present invention, when the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), the content of component (B) is more than 0.1% by mass and 1.5% by mass or less. In one embodiment of the present invention, the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), and the content of component (B) is 0.2% by mass or more and 1.0% by mass or less. Furthermore, when the surface treatment composition contains two or more components (B), the content of component (B) refers to their total amount.

[0077] Instead of the above, or in addition to the above, the mixing ratio of component (A) to component (B) in the surface treatment composition is appropriately set according to the type of component (A) or component (B) used and the desired effect. The mixing ratio of component (A) to component (B) (mass ratio) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably more than 0.3. The mixing ratio of component (A) to component (B) (mass ratio) is preferably 1.5 or less, more preferably 1.0 or less, and even more preferably less than 1.0. In one embodiment of the present invention, the mixing ratio of component (A) to component (B) (mass ratio) is 0.1 or more and 1.5 or less. In one embodiment of the present invention, the mixing ratio of component (A) to component (B) (mass ratio) is 0.2 or more and 1.0 or less. In one embodiment of the present invention, the mixing ratio of component (A) to component (B) (the ratio of component (A) to component (B)) (mass ratio) is greater than 0.3 and less than 1.0.

[0078] pH adjuster The surface treatment composition of the present invention must contain components (A) and (B) as described above, but preferably, in addition to these, it further contains a pH adjuster. That is, in a preferred embodiment of the present invention, the surface treatment composition further contains component (C): (C) Ingredients: pH adjuster.

[0079] There are no particular limitations on pH adjusters; any pH adjuster known in the field of surface treatment compositions can be used, including known acids, bases, or salts thereof. Examples of pH adjusters include: formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, pearlitic acid, stearic acid, oleic acid, linolenic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, lactic acid, malic acid, citric acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, and hexabenzoic acid. The pH adjuster can be a combination of various organic acids, including carboxylic acids such as cinnamic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, aconitic acid, amino acids, and anthraquinone; inorganic acids such as nitric acid, carbonic acid, hydrochloric acid, phosphoric acid, hypophosphoric acid, phosphorous acid, phosphonic acid, boric acid, hydrofluoric acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, metaphosphoric acid, and hexametaphosphoric acid; alkali metal hydroxides such as potassium hydroxide (KOH) and sodium hydroxide (NaOH); alkali metal carbonates such as potassium carbonate (K₂CO₃) and sodium carbonate (Na₂CO₃); hydroxides of Group 2 elements; ammonia (ammonium hydroxide); and organic bases such as quaternary ammonium hydroxide compounds. Synthetic or commercially available pH adjusters can be used. Furthermore, these pH adjusters can be used alone or in combination of two or more. Among these, potassium hydroxide, sodium hydroxide, ammonia, and sodium carbonate are preferred, more preferably potassium hydroxide, sodium hydroxide, and ammonia, and even more preferably ammonia. That is, in a preferred embodiment of the invention, the pH adjuster is selected from at least one of the group consisting of potassium hydroxide, sodium hydroxide, ammonia, and sodium carbonate. In a more preferred embodiment of the invention, the pH adjuster is selected from at least one of the group consisting of potassium hydroxide, sodium hydroxide, and ammonia. In an even more preferred embodiment of the invention, the pH adjuster is ammonia.

[0080] The amount of pH adjuster in the surface treatment composition can be appropriately selected to achieve the desired pH value of the surface treatment composition as detailed below.

[0081] [pH value of the surface treatment composition] The surface treatment composition of the present invention has a pH value of 8.0 or higher. If the pH value of the surface treatment composition is less than 8.0, it is impossible to sufficiently remove residues remaining on the surface of the object being ground. From the viewpoint of further improving the effect of the present invention, the pH value of the surface treatment composition is preferably greater than 8.0, more preferably greater than 8.5. The pH value of the surface treatment composition is preferably less than 11.0, more preferably less than 10.0. That is, in one embodiment of the present invention, the pH value of the surface treatment composition is greater than 8.0 and less than 11.0. In one embodiment of the present invention, the pH value of the surface treatment composition is 8.5 or higher and less than 10.0. Furthermore, the pH value of the surface treatment composition is a value measured by the method described in the examples.

[0082] [solvent] The surface treatment composition of the present invention preferably includes a solvent. The solvent has the function of dispersing or dissolving the components. The solvent preferably includes water, and more preferably only water. Alternatively, to disperse or dissolve the components, the solvent may be a mixture of water and an organic solvent. In this case, examples of organic solvents used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerol, ethylene glycol, propylene glycol, triethanolamine, etc., which are miscible with water. Alternatively, these organic solvents may be used without mixing with water to disperse or dissolve the components, and then mixed with water. These organic solvents may be used alone or in combination of two or more.

[0083] From the perspective of preventing contamination of the ground material or hindering the action of other components, the water is preferably as free of residue as possible. For example, water with a total transition metal ion content of less than 100 ppb is preferred. Here, the purity of the water can be improved, for example, by using ion exchange resins to remove residual ions, using filters to remove foreign matter, distillation, etc. Specifically, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc., are preferred.

[0084] [Surfactants] The surface treatment composition of the present invention may further include a surfactant. There is no particular limitation on the type of surfactant, which may be any one of nonionic, anionic, cationic, and amphoteric surfactants.

[0085] Examples of nonionic surfactants include: alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; alkyl phenyl ethers such as polyoxyethylene octylphenyl ether; alkyl esters such as polyoxyethylene lauryl ester; alkylamines such as polyoxyethylene laurylamine ether; alkylamines such as polyoxyethylene laurylamine; polypropylene glycol ethers such as polyoxyethylene polyoxypropylene ether; alkanolamines such as diethanolamine of oleate; and allylphenyl ethers such as polyoxyalkylene allyl ether. In addition, propylene glycol, diethylene glycol, monoethanolamine, alcohol ethoxides, alkylphenol ethoxides, triacetylenylidene glycol, and alkanolamines can also be used as nonionic surfactants.

[0086] Examples of anionic surfactants include: carboxylic acid types such as sodium myristate, sodium palmitate, sodium stearate, sodium laurate, and potassium laurate; sulfate types such as sodium octyl sulfate; phosphate types such as lauryl phosphate and sodium lauryl phosphate; and sulfonic acid types such as sodium dioctyl sulfosuccinate and sodium dodecylbenzene sulfonate.

[0087] Examples of cationic surfactants include compounds other than component (A) mentioned above, such as amines like laurylamine hydrochloride; quaternary ammonium salts like polyethoxyamine and lauryltrimethylammonium chloride; and pyridinium salts like laurylpyridinium chloride. Furthermore, since component (A) can function as a cationic surfactant, it is not necessary to add other cationic surfactants.

[0088] Examples of amphoteric surfactants include lecithin, alkylamine oxides, N-alkyl-N,N-dimethylammonium betaine, and other alkyl betaines or sulfobetaines.

[0089] Surfactants can be used alone or in combination of two or more. Furthermore, commercially available or synthetic surfactants can be used.

[0090] When the surface treatment composition contains a surfactant, with the total mass of the surface treatment composition set at 100% by mass, the lower limit of the surfactant content is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more. Furthermore, with the total mass of the surface treatment composition set at 100% by mass, the upper limit of the surfactant content in the surface treatment composition is preferably 5% by mass or less, and more preferably 1% by mass or less. Moreover, when the surface treatment composition contains two or more surfactants, the surfactant content refers to their total amount.

[0091] [Chlorinating agents] The surface treatment composition of the present invention may further include a chelating agent. Examples of chelating agents include aminocarboxylic acid chelating agents and organophosphonic acid chelating agents. Examples of aminocarboxylic acid chelating agents include: ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetic acid, hypozoxytriacetic acid, sodium hypozoxytriacetic acid, ammonium hypozoxytriacetic acid, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetic acid. Examples of organophosphonic acid chelating agents include: 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotris(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid) (EDTPO), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, and α-methylphosphonosuccinic acid. Among these, organophosphonic acid chelating agents are more preferred. Among the preferred examples are ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Ethylenediaminetetra(methylenephosphonic acid) and diethylenetriaminepenta(methylenephosphonic acid) are particularly preferred chelating agents.

[0092] Chelating agents can be used alone or in combination of two or more. Furthermore, commercially available or synthetic chelating agents can be used.

[0093] When the surface treatment composition contains a chelating agent, the total mass of the surface treatment composition is set as 100% by mass. The lower limit of the chelating agent content is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.002% by mass or more. The upper limit of the chelating agent content is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, and particularly preferably 0.15% by mass or less. Furthermore, when the surface treatment composition contains two or more chelating agents, the chelating agent content refers to their total amount.

[0094] [Other Additives] The surface treatment composition of one aspect of the present invention may also contain other additives in any proportion as needed, without hindering the effect of the present invention. However, since components other than the essential components of the surface treatment composition of one aspect of the present invention may become foreign matter (residue), it is ideal to add as few as possible, and therefore it is preferable to add as little as possible. Other additives include, for example, antifungal agents (preservatives), dissolved gases, reducing agents, oxidizing agents, etc. The surface treatment composition of the present invention is alkaline. Furthermore, the surface treatment composition of the present invention contains a polymer ((A) component). Therefore, among these, the surface treatment composition of the present invention preferably contains an antifungal agent (preservative). When the surface treatment composition of the present invention contains an antifungal agent (preservative), there are no particular limitations on the antifungal agent (preservative) that can be used, and it can be appropriately selected according to the type of polymer ((A) component). Specifically, examples include isothiazolin-based preservatives such as 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, and 1,2-benzisothiazolin-3(2H)-one (BIT), as well as phenoxyethanol.

[0095] Alternatively, the antifungal agent (preservative) may be a compound represented by the following chemical formula 1.

[0096] [Chemistry 10] (Chemical Formula 1)

[0097] In the above chemical formula 1, R1 to R5 are each independently a hydrogen atom or a substituent containing at least two atoms selected from the group consisting of carbon, hydrogen, and oxygen atoms.

[0098] Examples of substituents that include at least two atoms selected from the group consisting of carbon, hydrogen, and oxygen atoms include: hydroxyl, carboxyl, alkyl with 1 or more carbon atoms and 20 or less, hydroxyalkyl with 1 or more carbon atoms and 20 or less, alkoxy with 1 or more carbon atoms and 20 or less, hydroxyalkoxy with 1 or more carbon atoms and 20 or less, alkoxycarbonyl with 2 or more carbon atoms and 21 or less, aryl with 6 or more carbon atoms and 30 or less, aralkyl with 7 or more carbon atoms and 31 or less, aryloxy with 6 or more carbon atoms and 30 or less, aryloxycarbonyl with 6 or more carbon atoms and 30 or less, arylalkoxycarbonyl with 8 or more carbon atoms and 32 or less, acetyl with 2 or more carbon atoms and acetyloxy, etc.

[0099] More specifically, examples of alkyl groups with 1 or more carbon atoms but less than 20 include: straight-chain alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; branched-chain alkyl groups such as isopropyl, isobutyl, dibutyl, tributyl, tripentyl, neopentyl, 3-methylpentyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-methyl-1-propylbutyl, 1,1-dipropylbutyl, 1,1-dimethyl-2-methylpropyl, and 1-methyl-1-isopropyl-2-methylpropyl; and cyclic alkyl groups such as cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and norethenyl.

[0100] Examples of hydroxyalkyl groups with 1 or more carbon atoms and less than 20 include: hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 3-hydroxybutyl, 4-hydroxybutyl, 2-hydroxypentyl, 3-hydroxypentyl, 4-hydroxypentyl, 5-hydroxypentyl, 2-hydroxyhexyl, 3-hydroxyhexyl, 4-hydroxyhexyl, 5-hydroxyhexyl, 6-hydroxyhexyl, etc.

[0101] Examples of alkoxy groups with 1 or more carbon atoms but less than 20 include: straight-chain alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentooxy, hexoxy, heptoxy, octoxy, nonoxy, and decoxy; branched-chain alkoxy groups such as isopropoxy, isobutoxy, dibutoxy, terbutoxy, terpentoxy, neopentoxy, 3-methylpentoxy, 1,1-diethylpropoxy, 1,1-dimethylbutoxy, 1-methyl-1-propylbutoxy, 1,1-dipropylbutoxy, 1,1-dimethyl-2-methylpropoxy, and 1-methyl-1-isopropyl-2-methylpropoxy; and cyclic alkoxy groups such as cyclobutoxy, cyclopentoxy, cyclohexoxy, cycloheptoxy, cyclooctoxy, and norethenoxy.

[0102] Examples of hydroxyalkoxy groups with 1 or more carbon atoms but less than 20 include: hydroxymethoxy, 2-hydroxyethoxy, 2-hydroxypropoxy, 3-hydroxypropoxy, 2-hydroxybutoxy, 3-hydroxybutoxy, 4-hydroxybutoxy, 2-hydroxypentoxy, 3-hydroxypentoxy, 4-hydroxypentoxy, 5-hydroxypentoxy, 2-hydroxyhexoxy, 3-hydroxyhexoxy, 4-hydroxyhexoxy, 5-hydroxyhexoxy, 6-hydroxyhexoxy, etc.

[0103] Examples of alkoxycarbonyl groups with 2 or more carbon atoms but less than 21 include: methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, hexoxycarbonyl, octoxycarbonyl, decoxycarbonyl, etc.

[0104] Examples of aryl groups with 6 or more carbon atoms but less than 30 include: phenyl, naphthyl, anthraceneyl, pyrene, etc.

[0105] Examples of aralkyl compounds with 7 or more carbon atoms and 31 or fewer include benzyl and phenylethyl. Examples of aryloxy compounds with 6 or more carbon atoms and 30 or fewer include phenoxy, naphthoxy, anthraceneoxy, and pyreneoxy.

[0106] Examples of aryloxycarbonyl groups with 7 or more carbon atoms and 31 or fewer include: phenoxycarbonyl, naphthoxycarbonyl, anthraceneoxycarbonyl, pyreneoxycarbonyl, etc.

[0107] Examples of aryl alkoxy carbonyl groups with 8 or more carbon atoms and 32 or fewer include benzyloxy carbonyl and phenylethoxy carbonyl.

[0108] Examples of acetylated groups with 1 or more carbon atoms but less than 20 include: methanoyl, ethanoyl, propionic acid, butyl, pentayl, hexyl, octyl, decyl, benzoyl, etc.

[0109] Examples of acetylated groups with 1 or more carbon atoms but less than 20 include: methoxy, ethoxy, propoxy, butoxy, pentaoxy, hexoxy, octaoxy, decoxy, benzoxy, etc.

[0110] Furthermore, the antifungal agent represented by the above chemical formula 1 is preferably selected from at least one of the compounds represented by the following chemical formulas 1-a to 1-c.

[0111] [Chemistry 11]

[0112] In the above chemical formulas 1-a to 1-c, R1 to R3 are each independently a substituent containing at least two types of atoms selected from the group consisting of carbon, hydrogen, and oxygen atoms.

[0113] Examples of substituents that include at least two types of atoms selected from the group consisting of carbon, hydrogen, and oxygen atoms are the same as those described above, so the explanation is omitted here.

[0114] More specific examples of compounds represented by the above chemical formula 1 include: methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, and other p-hydroxybenzoate esters; salicylic acid, methyl salicylate, phenol, catechol, resorcinol, hydroquinone, isopropylphenol, cresol, thymol, phenoxyethanol, phenylphenol (2-phenylphenol, 3-phenylphenol, 4-phenylphenol), 2-phenylethanol (phenylethanol), etc.

[0115] Among these, from the viewpoint of more effectively achieving the desired effects of the present invention, the compound represented by the above chemical formula 1 is preferably selected from at least one of the group consisting of ethyl p-hydroxybenzoate, butyl p-hydroxybenzoate, and phenylphenol, and more preferably butyl p-hydroxybenzoate.

[0116] Alternatively, antifungal agents (preservatives) can be unsaturated fatty acids. Examples of unsaturated fatty acids include: monounsaturated fatty acids such as butenoic acid, myristoleic acid, palmitoleic acid, oleic acid, and ricinoleic acid; diunsaturated fatty acids such as sorbic acid, linoleic acid, and eicosapentaenoic acid; triunsaturated fatty acids such as linolenic acid, terpineic acid, and tungsten acid; tetraunsaturated fatty acids such as octadecanoic acid or arachidonic acid; pentaunsaturated fatty acids such as heptapentenoic acid and eicosapentaenoic acid; and hexaunsaturated fatty acids such as docosahexaenoic acid and herring acid.

[0117] Among these, from the viewpoint of more effectively achieving the desired effects of the present invention, sorbic acid is preferred as an unsaturated fatty acid.

[0118] In addition to the above, compounds such as 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, alkyl glycerol ethers such as 2-ethylhexylglycerol ether (ethylhexylglycerol), decanoic acid, and dehydroacetic acid can also be used as antifungal agents (preservatives).

[0119] The above-mentioned antifungal agents (preservatives) can be used alone or in combination of two or more.

[0120] When the surface treatment composition contains an antifungal agent (preservative), there is no particular limitation on the lower limit of the content (concentration) of the antifungal agent (preservative), but it is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more. Furthermore, there is no particular limitation on the upper limit of the content (concentration) of the antifungal agent (preservative), but it is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. That is, the content (concentration) of the antifungal agent (preservative) in the surface treatment composition is preferably 0.0001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 1% by mass or less, even more preferably 0.005% by mass or more and 0.5% by mass or less, and even more preferably 0.01% by mass or more and 0.1% by mass or less. If this range is achieved, an effect sufficient to inert or destroy microorganisms can be obtained. Furthermore, when the surface treatment composition contains two or more antifungal agents (preservatives), the above content refers to the total amount of these.

[0121] That is, in one embodiment of the present invention, the surface treatment composition substantially comprises at least one selected from the group consisting of a polymer (component (A)), a buffer (component (B)), a pH adjuster and water, and an antifungal agent, an organic solvent, a surfactant and a chelating agent. In one embodiment of the present invention, the surface treatment composition substantially comprises at least one selected from the group consisting of a polymer (component (A)), a buffer (component (B)), a pH adjuster and water, and an antifungal agent and an organic solvent. In one embodiment of the present invention, the surface treatment composition substantially comprises a polymer (component (A)), a buffer (component (B)), a pH adjuster and water. In this embodiment, "the surface treatment composition substantially comprises X" means that the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), and the total content of X exceeds 99% by mass (maximum: 100% by mass). Preferably, the surface treatment composition comprises X (the above total content = 100% by mass). For example, "the surface treatment composition substantially comprises a polymer ((A) component), a buffer ((B) component), a pH adjuster and water, and at least one of an antifungal agent and an organic solvent" means that the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), and the total content of the polymer ((A) component), the buffer ((B) component), the pH adjuster and water, and the antifungal agent and organic solvent exceeds 99% by mass (maximum: 100% by mass). Preferably, the surface treatment composition comprises at least one of the polymer ((A) component), the buffer ((B) component), the pH adjuster and water, and the antifungal agent and organic solvent (the total content of the above = 100% by mass).

[0122] To further improve the removal effect of residues (foreign matter), the surface treatment composition of the present invention is preferably substantially free of abrasive particles. Here, "substantially free of abrasive particles" means that the content of abrasive particles is less than 0.01% by mass relative to the entire surface treatment composition. That is, in one embodiment of the present invention, the total mass of the surface treatment composition is set to 100% by mass (relative to the surface treatment composition), and the content of abrasive particles is less than 0.01% by mass (lower limit: 0% by mass).

[0123] <Method for Manufacturing Surface Treatment Compositions> The method for manufacturing the surface treatment composition of the present invention is not particularly limited. For example, it can be obtained by stirring and mixing at least one of the following groups: component (A) (polymer), component (B) (buffer), and, as needed, pH adjuster, surfactant, chelating agent, water, organic solvent, antifungal agent (preservative), and other additives. In one embodiment of the present invention, the surface treatment composition of the present invention is manufactured by stirring and mixing at least one of the following groups: polymer (component (A)), buffer (component (B)), pH adjuster, water, and antifungal agent, organic solvent, surfactant, and chelating agent. In one embodiment of the present invention, the surface treatment composition of the present invention is manufactured by stirring and mixing at least one of the following groups: polymer (component (A)), buffer (component (B)), pH adjuster, water, and antifungal agent and organic solvent. In one embodiment of the present invention, the surface treatment composition of the present invention is prepared by stirring and mixing component (A) (polymer), component (B) (buffer), water, and pH adjuster. There are no particular limitations on the temperature during mixing of the components, but it is preferably above 10°C and below 40°C. Heating may also be performed to increase the dissolution rate. Furthermore, there are no particular limitations on the mixing time.

[0124] <Surface Treatment Methods> According to the surface treatment composition of the present invention, residues remaining on the surface of a polished object can be sufficiently removed. Furthermore, the etching rate of a polished object containing polycrystalline silicon can be suppressed to a low level. Therefore, the present invention provides a surface treatment method comprising the step of: performing surface treatment on a polished object using the surface treatment composition of the present invention. Here, the polished object may contain at least one selected from the group consisting of silicon nitride, silicon oxide, and polycrystalline silicon. That is, the present invention provides a surface treatment method that uses the surface treatment composition of the present invention to perform surface treatment on a polished object containing at least one selected from the group consisting of silicon nitride, silicon oxide, and polycrystalline silicon, thereby reducing residues on the surface of the polished object. Furthermore, in this specification, "surface treatment method" refers to a method for reducing residues on the surface of a polished object, and is a method of cleaning in a broad sense.

[0125] According to the surface treatment method of the present invention, residues remaining on the surface of a polished object can be sufficiently removed. That is, the present invention also provides a method for reducing residues on the surface of a polished object, comprising the following steps: performing surface treatment on the polished object using the surface treatment composition of the present invention. Furthermore, the present invention provides a method for reducing residues on the surface of a polished object, comprising the following steps: performing surface treatment on a polished object comprising at least one of silicon nitride, silicon oxide, and polycrystalline silicon using the surface treatment composition of the present invention.

[0126] The surface treatment method of the present invention is carried out by bringing the surface treatment composition of the present invention into direct contact with the polished object.

[0127] As surface treatment methods, the main examples are: (I) a method using rinsing and grinding, and (II) a method using washing. That is, in one embodiment of the present invention, the surface treatment method is a rinsing and grinding method or a washing method (the above surface treatment is performed by rinsing and grinding or washing). The rinsing and grinding process and the washing process are performed to remove foreign matter (abrasive particle residue, organic residue such as polymer or pad shavings, metal contaminants, etc.) from the surface of the object being ground, in order to obtain a clean surface. Hereinafter, (I) and (II) will be described.

[0128] (I) Washing and grinding treatment The surface treatment composition of the present invention can be suitably used in rinsing and polishing processes. That is, the surface treatment composition of the present invention is preferably used as a rinsing and polishing composition. A rinsing and polishing process is performed on a polishing plate (pressure plate) with a polishing pad mounted on it after the object to be polished has undergone final polishing (fine polishing) to obtain a polished object. At this time, the rinsing and polishing process is performed by bringing the surface treatment composition of the present invention into direct contact with the polished object. As a result, foreign matter on the surface of the polished object is removed by friction (physical action) based on the polishing pad and by chemical action based on the surface treatment composition. In particular, abrasive particle (microparticle) residues or organic residues are easily removed by physical action. Therefore, in a rinsing and polishing process, abrasive particle (microparticle) residues or organic residues can be effectively removed by friction with the polishing pad on the polishing plate (pressure plate).

[0129] That is, in this specification, rinsing and polishing treatment, rinsing and polishing method and rinsing and polishing steps refer to the treatment, method and steps of using a polishing pad to reduce the residue on the surface of the object to be treated.

[0130] Specifically, the rinsing and polishing process can be carried out by the following method: the polished object after the polishing step is placed on the polishing plate (plate) of the polishing device, while the polishing pad contacts the polished semiconductor substrate and a surface treatment composition is supplied to the contact area, and the polished object slides relative to the polishing pad.

[0131] As a grinding device, a conventional grinding device can be used, which is equipped with a holder to hold the object to be ground, a motor that can change the speed, and a grinding pressure plate that can attach a grinding pad (grinding cloth).

[0132] The rinsing and grinding process can be performed using either a single-sided grinding device or a double-sided grinding device. Furthermore, the aforementioned grinding device is preferably equipped with a nozzle for spraying the surface treatment composition, in addition to the nozzle for spraying the grinding composition. There are no particular restrictions on the operating conditions of the grinding device during the rinsing and grinding process; any operator can set them appropriately.

[0133] As an abrasive pad, commonly used non-woven fabrics, polyurethanes, and porous fluoropolymers can be used without particular restrictions. Preferably, the abrasive pad is processed with grooves for storing surface treatment compositions.

[0134] There are no particular restrictions on the rinsing and grinding conditions. For example, the rotational speed of the grinding disc and the grinding head (carrier) are preferably 10 rpm (0.17 s⁻¹) or more and 100 rpm (1.67 s⁻¹) or less. The pressure applied to the object being ground (grinding pressure) is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. There are also no particular restrictions on the method of supplying the surface treatment composition to the grinding pad. For example, a continuous supply method using a pump (pour) can be used. The supply rate is not limited, but it is preferable that the surface of the grinding pad is always covered by the surface treatment composition, preferably 10 mL / min or more and 5000 mL / min or less. There are also no particular restrictions on the rinsing and grinding time, but it is preferably 5 seconds or more and 180 seconds or less.

[0135] After rinsing and grinding using the surface treatment composition of the present invention, the ground object (surface treatment object) is preferably lifted and removed while the surface treatment composition of the present invention is being poured on it.

[0136] (II) Cleaning treatment The surface treatment composition of the present invention can be used in cleaning processes. That is, the surface treatment composition of the present invention is preferably used as a cleaning composition. The cleaning process is preferably performed after the object to be ground has undergone final grinding (fine grinding), followed by the aforementioned rinsing and grinding process, or by other rinsing and grinding processes using a rinsing and grinding composition other than the surface treatment composition of the present invention, to obtain a ground object (cleaned object), and is performed to remove foreign matter from the surface of the ground object (cleaned object). Furthermore, the cleaning process and the aforementioned rinsing and grinding process are classified according to the location where these processes are performed. The cleaning process is a surface treatment performed in a location other than on a grinding plate (press plate), preferably after the ground object has been removed from the grinding plate (press plate). During the cleaning process, the surface treatment composition of the present invention can also be brought into direct contact with the ground object to remove foreign matter from its surface.

[0137] Examples of cleaning methods include: (i) a method in which a cleaning brush is brought into contact with one or both sides of the polished object while it is being polished, and a surface treatment composition is supplied to the contact area while the surface of the object is being cleaned by rubbing with the cleaning brush; (ii) a method in which the polished object is immersed in a surface treatment composition and subjected to ultrasonic treatment or agitation (immersion type). In this method, foreign matter on the surface of the polished object is removed by utilizing the friction caused by the cleaning brush, the mechanical force generated by ultrasonic treatment or agitation, and the chemical action caused by the surface treatment composition.

[0138] In the method described in (i) above, there is no particular limitation on the method of contacting the surface treatment composition with the polished object. Examples include: a rotary method in which the surface treatment composition flows from the nozzle onto the polished object while the polished object is rotated at high speed; and a spray method in which the surface treatment composition is sprayed onto the polished object and then washed.

[0139] From the perspective of removing contaminants more efficiently in a short time, the washing process is preferably carried out by rotary or spray methods, and more preferably by rotary methods.

[0140] Apparatus for performing this type of cleaning process includes: batch cleaning apparatus that simultaneously treats multiple polished objects stored in a box; and single-piece cleaning apparatus that performs surface treatment on a single polished object mounted in a holder. From the viewpoint of shortening cleaning time, the method of using a single-piece cleaning apparatus is preferred.

[0141] Furthermore, as an apparatus for performing cleaning, an example of a grinding device can be given, which includes a cleaning device that removes the object to be ground from the grinding plate (pressure plate) and then uses a cleaning brush to rub the object. By using such a grinding device, the cleaning process of the ground object can be performed more efficiently.

[0142] As such a grinding device, a conventional grinding device can be used, which includes a holder for holding the object to be ground, a motor capable of changing the rotation speed, a cleaning brush, etc. Either a single-sided grinding device or a double-sided grinding device can be used. Furthermore, when a rinsing and grinding step is performed after the CMP step, it is more efficient and preferable to use the same device as the grinding device used in the rinsing and grinding step for this cleaning process.

[0143] There are no particular restrictions on the cleaning brush, but resin brushes are preferred. There are no particular restrictions on the material of resin brushes, but PVA (polyvinyl alcohol) is preferred. PVA sponges are even more preferred for cleaning brushes.

[0144] The cleaning conditions are not particularly limited and can be appropriately set according to the type of the surface-treated object (the object being ground) and the type and amount of residue to be removed. For example, the rotation speed of the cleaning brush is preferably 10 rpm (0.17 s⁻¹) or more and 200 rpm (3.33 s⁻¹) or less, and the rotation speed of the object being cleaned is preferably 10 rpm (0.17 s⁻¹) or more and 100 rpm (1.67 s⁻¹) or less. The method of supplying the surface treatment composition to the cleaning brush is also not particularly limited; for example, a continuous supply method using a pump (rinsing) can be used. The supply amount is not limited, but it is preferable that the cleaning brush and the surface of the object being cleaned are always covered by the surface treatment composition, preferably 10 mL / min or more and 5000 mL / min or less. The cleaning time is also not particularly limited, and the step of using the surface treatment composition of one aspect of the present invention is preferably 5 seconds or more and 180 seconds or less. If this range is used, foreign objects can be removed more effectively.

[0145] There are no particular restrictions on the temperature of the surface treatment composition during cleaning. It can usually be room temperature, or heated to around 40°C or below 70°C without impairing performance.

[0146] In the method described in (ii) above, there are no particular restrictions on the conditions for using the immersion cleaning method, and known methods may be used.

[0147] Before surface treatment by the methods described in (I) or (II) above, the surface can also be washed with water.

[0148] (Follow-up washing process) Furthermore, as a surface treatment method, it is preferable to perform a cleaning treatment on the polished object after surface treatment using the surface treatment composition of the present invention in (I) or (II) described above. In this specification, this cleaning treatment is referred to as post-cleaning treatment. There are no particular limitations on the post-cleaning treatment; for example, methods such as rinsing the surface-treated object with water or immersing the surface-treated object in water can be cited. Similarly, as with the surface treatment using method (II) described above, the following methods can be cited: while holding the surface-treated object, contacting one or both sides of the surface-treated object with a cleaning brush, supplying water or an aqueous solution (e.g., NH3 aqueous solution) to the contact portion, or supplying water and an aqueous solution (e.g., NH3 aqueous solution) in any order (supplying water followed by a solution, or supplying water followed by an aqueous solution), while rubbing the surface of the surface-treated object with a cleaning brush (brush cleaning); immersing the surface-treated object in water for ultrasonic treatment or stirring (immersion type). Among these methods, it is preferable to maintain the object to be treated while simultaneously contacting one or both sides of the object with a cleaning brush, supplying water or an aqueous solution (e.g., an NH3 aqueous solution) to the contact area, or supplying water and an aqueous solution (e.g., an NH3 aqueous solution) in any sequence (supplying water after supplying aqueous solution, or supplying water after supplying NH3 aqueous solution), and rubbing the surface of the object with the cleaning brush. Furthermore, the apparatus and conditions for the post-cleaning treatment can be referred to the surface treatment description in (II) above. Here, deionized water is particularly preferred as the water used in the post-cleaning treatment.

[0149] Surface treatment using the surface treatment composition of one aspect of the present invention results in a state where residues are extremely easy to remove. Therefore, by further rinsing with water after surface treatment using the surface treatment composition of one aspect of the present invention, residues are removed very well. Deionized water is particularly preferred as the water used in this process.

[0150] <Semiconductor substrate manufacturing method> The surface treatment method of the present invention is suitable for use when the object to be polished is a polished semiconductor substrate. That is, the present invention also provides a method for manufacturing a semiconductor substrate, wherein the object to be polished is a polished semiconductor substrate, and the method includes the following steps: reducing the residue on the surface of the polished semiconductor substrate by the above-described surface treatment method.

[0151] At this time, the polished object includes at least one of silicon nitride, silicon oxide, and polycrystalline silicon. That is, the present invention also provides a method for manufacturing a semiconductor substrate, wherein the polished object is a polished semiconductor substrate. The method for manufacturing the semiconductor substrate includes the following steps: a polishing step, which uses a polishing composition containing abrasive particles to polish a pre-polishing semiconductor substrate containing at least one of silicon nitride, silicon oxide, and polycrystalline silicon to obtain a polished semiconductor substrate; and a surface treatment step, which uses the surface treatment composition of the present invention to reduce residue containing the abrasive particles on the surface of the polished semiconductor substrate.

[0152] Details regarding the semiconductor substrates for which this manufacturing method is applied include a description of the polished object that has undergone surface treatment using the aforementioned surface treatment composition.

[0153] Furthermore, there are no particular limitations on the method for manufacturing a semiconductor substrate as long as it includes a step of surface treatment (surface treatment step) of using the surface treatment composition of the present invention to treat the surface of the polished semiconductor substrate. For example, such a manufacturing method may include a polishing step and a cleaning step for forming the polished semiconductor substrate. As another example, a method may include a rinsing polishing step between the polishing and cleaning steps, in addition to the polishing and cleaning steps. These steps will be described below.

[0154] [Grinding Steps] The grinding step that may be included in the manufacturing method of a semiconductor substrate is the step of grinding the semiconductor substrate to form a ground semiconductor substrate.

[0155] The polishing step is not particularly limited as long as it involves polishing a semiconductor substrate, but chemical mechanical polishing (CMP) is preferred. Furthermore, the polishing step can be a single step or a multiple step. Examples of multiple steps include: a fine polishing step performed after a pre-polishing step (rough polishing step); or a two-step polishing process performed after one polishing step, followed by a fine polishing step. The surface treatment step using the surface treatment composition of the present invention is preferably performed after the aforementioned fine polishing step.

[0156] As a polishing composition, a known polishing composition may be appropriately used depending on the characteristics of the semiconductor substrate. There are no particular limitations on the polishing composition, and examples include polishing compositions containing abrasive particles, water-soluble polymers, pH adjusters, and solvents.

[0157] The abrasive particles can be any of inorganic particles, organic particles, or organic-inorganic composite particles. Specific examples of inorganic particles include particles containing metal oxides such as silicon dioxide, aluminum oxide, cerium oxide, and titanium oxide, as well as silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles. Furthermore, the abrasive particles can be commercially available or synthetic. Moreover, unless otherwise specified in this specification, abrasive particles refer to those without surface modification. A single abrasive particle can be used, or two or more can be used in combination. Among these abrasive particles, silicon dioxide is preferred, and colloidal silicon dioxide is more preferred.

[0158] The lower limit of the average primary particle size of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, further preferably 20 nm or more, and especially preferably 30 nm or more. Within this range, a higher grinding speed can be maintained, making it suitable for use in the coarse grinding step. Furthermore, the upper limit of the average primary particle size of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, and further preferably 100 nm or less. In some cases, the average primary particle size may be 75 nm or less, 60 nm or less, or 50 nm or less. Within this range, defects on the surface of the object being ground can be further suppressed. Moreover, the average primary particle size of the abrasive grains is calculated, for example, based on the specific surface area of ​​the abrasive grains measured by the BET method.

[0159] The lower limit of the average secondary particle size of the abrasive grains is preferably 15 nm or more, more preferably 30 nm or more, further preferably 40 nm or more, further preferably 50 nm or more, and especially preferably 60 nm or more. Within this range, a higher grinding speed can be maintained. Furthermore, the upper limit of the average secondary particle size of the abrasive grains is preferably 300 nm or less, more preferably 200 nm or less, further preferably 150 nm or less, further preferably 100 nm or less, and especially preferably 80 nm or less. Within this range, defects on the surface of the object being ground can be further suppressed. The average secondary particle size of the abrasive grains can be measured by dynamic light scattering. For example, it can be measured using the "FPAR-1000" model manufactured by Otsuka Electronics Co., Ltd., or an equivalent product.

[0160] When the grinding composition is directly formulated into a grinding slurry for use, the content of abrasive particles relative to the grinding composition is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and even more preferably 1.0% by mass or more. Increasing the content of abrasive particles improves the grinding speed. Furthermore, when the grinding composition is directly formulated into a grinding slurry for use, from the viewpoint of preventing scratches, the content of abrasive particles is generally more appropriate to be 10% by mass or less, preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less. From an economic point of view, it is also preferable to reduce the content of abrasive particles. Moreover, when two or more types of abrasive particles are used in combination, the above-mentioned content refers to the total content of the two or more types of abrasive particles.

[0161] Examples of water-soluble polymers include: cellulose derivatives, starch derivatives, polymers containing alkyl groups, polymers containing nitrogen atoms, and vinyl alcohol polymers. Specific examples include: hydroxyethyl cellulose, amylopectin, random copolymers or block copolymers of ethylene oxide and propylene oxide, polyvinyl alcohol, acetalized polyvinyl alcohol, copolymers of vinyl alcohol and alkyl oxides, polyisoprene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyisoprene sulfonic acid, polystyrene sulfonate, polyacrylate, polyvinyl acetate, polyethylene glycol, polyvinylimazole, polyvinylcarbazole, polyvinylpyrrolidone, polyvinylcaprolactone, polyvinylpiperidine, polyacrylamide, and polyhydroxyacrylamide. Water-soluble polymers can be used alone or in combination of two or more. The grinding compositions disclosed herein are preferably implemented even if they are substantially free of water-soluble polymers, i.e., at least intentionally free of water-soluble polymers.

[0162] When the grinding composition is directly formulated into a grinding slurry for use, the content of the water-soluble polymer relative to the grinding composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more. Furthermore, when the grinding composition is directly formulated into a grinding slurry for use, the content is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. Moreover, when two or more water-soluble polymers are used in combination, the above-mentioned content refers to the total content of the two or more water-soluble polymers.

[0163] The pH adjuster and solvent are the same as those specified in the sections on [pH adjuster] and [solvent] above, and therefore descriptions are omitted here. Among these, the pH adjuster is preferably potassium hydroxide, sodium hydroxide, or ammonia, and more preferably ammonia. Furthermore, the solvent is preferably water-containing, and more preferably water only.

[0164] When the grinding composition is directly formulated into a grinding fluid for use, it is preferable that the pH value of the grinding composition is higher than that of the surface treatment composition of the present invention (above 8.0), more preferably 8.5 or higher, even more preferably 9.5 or higher, and particularly preferably 10.0 or higher. If the pH value of the grinding composition increases, the grinding speed increases. On the other hand, when the grinding composition is directly formulated into a grinding fluid for use, it is preferable that the pH value of the grinding composition is 12.0 or lower, more preferably 11.5 or lower. If the pH value of the grinding composition is 12.0 or lower, the dissolution of the abrasive particles can be inhibited, preventing a reduction in the mechanical grinding effect caused by the abrasive particles. Furthermore, the pH value of the grinding composition is a value measured by the method described in the examples.

[0165] As a grinding device, a conventional grinding device can be used, which is equipped with a holder to hold the object to be ground, a motor that can change the rotation speed, and a grinding pressure plate for attaching a grinding pad (grinding cloth). As a grinding device, either a single-sided grinding device or a double-sided grinding device can be used.

[0166] As a polishing pad, there are no particular limitations on the use of common non-woven fabrics, polyurethanes, and porous fluoropolymers. Preferably, the polishing pad is machined with a groove for storing polishing fluid.

[0167] There are no particular limitations on the grinding conditions. For example, the rotational speed of the grinding disc and the grinding head (carrier) are preferably 10 rpm (0.17 s⁻¹) or more and 100 rpm (1.67 s⁻¹) or less. The pressure applied to the object being ground (grinding pressure) is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. There are also no particular limitations on the method of supplying the grinding composition to the grinding pad; for example, a continuous supply method using a pump (pour) can be used. The supply rate is not limited, but it is preferable that the surface of the grinding pad is always covered by the grinding composition, preferably 10 mL / min or more and 5000 mL / min or less. There are also no particular limitations on the grinding time, but the steps involving the use of the grinding composition are preferably 5 seconds or more and 180 seconds or less.

[0168] [Surface Treatment Steps] The surface treatment step refers to the step of using the surface treatment composition of the present invention to reduce residues on the surface of the polished object. In the manufacturing method of semiconductor substrate, a cleaning step as a surface treatment step may be performed after the rinsing and polishing step, or only the rinsing and polishing step or only the cleaning step may be performed.

[0169] (Rinsing and grinding steps) In the manufacturing method of semiconductor substrates, the rinsing and polishing step can also be set between the polishing step and the cleaning step. The rinsing and polishing step is a step to reduce foreign matter on the surface of the polished object (polished semiconductor substrate) by means of a surface treatment method (rinsing and polishing treatment method) of one aspect of the present invention.

[0170] The details of the rinsing and grinding method used in the rinsing and grinding step are as described in the above description of the rinsing and grinding process.

[0171] (Washing steps) In the manufacturing method of a semiconductor substrate, the cleaning step can be set after the polishing step or after rinsing the polishing step. The cleaning step is a step to reduce foreign matter on the surface of the polished object (polished semiconductor substrate) by means of a surface treatment method (cleaning method) of one aspect of the present invention.

[0172] The details of the washing method used in the washing step are the same as those in the above (post-washing treatment). The embodiments of the present invention have been described in detail above. They are illustrative and exemplary and are not limiting. It is clear that the scope of the present invention should be interpreted in accordance with the appended claims. The present invention includes the following forms and shapes. 1. A surface treatment composition comprising component (A) and component (B) and having a pH value of 8.0 or higher: (A) component: a polymer containing structural units having a quaternary nitrogen-containing onium salt structure or structural units of structure (X) below: [Chemistry 12] In the above structure (X), R 31 to R 34 independently represent hydrogen atoms or straight-chain or branched alkyl groups having 1 or more but less than 10 carbon atoms; (B) Composition: Buffer represented by the formula: R-COO-NH4+ (R is a straight-chain or branched alkyl or phenyl group with 1 or more carbon atoms and less than 10 carbon atoms); 2. The surface treatment composition as described in 1. above, wherein component (A) comprises a polymer containing structural units having a quaternary nitrogen-containing onium salt; 3. The surface treatment composition as described in 1. or 2. above, wherein the structural unit having a quaternary nitrogen-containing onium salt is only the following structure (Y) or the following structure (Z): [Chemistry 13] In the above structure (Y), R11 represents a hydrogen atom or a methyl group, R12 represents a straight-chain or branched alkyl group with 1 or more but less than 10 carbon atoms, R13 to R15 each independently represent a straight-chain or branched alkyl group with 1 or more but less than 10 carbon atoms, and X1 represents an anionic portion; [Chemistry 14] In the above structure (Z), R 21 and R 22 independently represent hydrogen atoms, alkyl groups with 1 or more carbon atoms and 3 or fewer carbon atoms, or phenyl groups; R 23 and R 24 independently represent straight-chain or branched alkyl groups with 1 or more carbon atoms and 10 or fewer carbon atoms; and X 2 represents an anionic portion. 4. The surface treatment composition described in any one of 1. to 3. above does not substantially contain abrasive particles; 5. The surface treatment composition as described in any one of 1. to 4. above, wherein the polymer is contained in the surface treatment composition at a ratio of more than 0.05% by mass; 6. The surface treatment composition as described in any one of 1. to 5. above, wherein the buffer is ammonium acetate; 7. The surface treatment composition as described in any one of 1 to 6 above, further comprising component (C): (C) Ingredients: pH adjuster; 8. The surface treatment composition as described in 7. above, wherein the pH adjuster is ammonia; 9. A surface treatment method comprising using a surface treatment composition as described in any one of 1 to 8 above to surface treat a polished abrasive object comprising at least one of silicon nitride, silicon oxide, and polycrystalline silicon, thereby reducing residue on the surface of the polished abrasive object; 10. The surface treatment method described in 9. above is a rinsing and polishing treatment method or a cleaning treatment method; 11. A method for manufacturing a semiconductor substrate, wherein the object to be polished is a polished semiconductor substrate, and the method for manufacturing the semiconductor substrate includes the following steps: The polishing step involves polishing a semiconductor substrate containing at least one of silicon nitride, silicon oxide, and polycrystalline silicon using a polishing composition comprising abrasive particles, to obtain a polished semiconductor substrate; and A surface treatment step, which uses a surface treatment composition as described in any one of 1 to 8 above, to reduce the residue containing the abrasive particles on the surface of the polished semiconductor substrate; 12. The method for manufacturing a semiconductor substrate as described in 11 above, wherein the pH value of the polishing composition is 8.5 or higher. [Example]

[0173] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Furthermore, unless otherwise specified, "%" and "parts" refer to "mass %" and "parts by mass," respectively. Also, in the following examples, unless otherwise specified, the operation is carried out at room temperature (25°C) and relative humidity of 40%RH or higher and 50%RH or lower.

[0174] <Preparation of (A) Ingredients, (B) Ingredients and pH Adjuster> Prepare the following ingredients (A), (B), and pH adjuster.

[0175] [(A)Component] Dimethyl diallyl ammonium chloride / acrylic acid copolymer (DADMAC / AA): Merquat TM295 polymer (Japan Lubrizol) (polytetraammonium-22), Mw=190,000 (also known as "DADMAC / AA") Dimethyl diallyl ammonium chloride / acrylamide copolymer (DADMAC / Aam): Merquat TM550 polymer (Japan Lubrizol) (polytetraammonium-7), Mw=1,600,000 (also known as "DADMAC / Aam") Polydimethyl diallyl ammonium chloride (polydimethylmethylenepiperidinium chloride) (polyDADMAC): UNISENSE FPA-100L (Senka Corporation), Mw=less than 20,000 (also known as "polyDADMAC1") Polydimethyl diallyl ammonium chloride (polydimethylmethylenepiperidinium chloride) (polyDADMAC): UNISENSE FPA-102L (Senka Corporation), Mw=20,000~100,000 (also known as "polyDADMAC2") Polydimethyl diallyl ammonium chloride (polydimethylmethylenepiperidinium chloride) (polyDADMAC): UNISENSE FPA-1000L (Senka Corporation), Mw=100,000~500,000 (also known as "polyDADMAC3") Polyalkyl polyamine-dicyandiamide ammonium salt condensate (dicyandiamide (DCDA) / diethylenetriamine (DETA)): UNISENSE KHP10P (Senka Corporation), Mw=less than 20,000 (also known as "DCDA / DETA") Methacrylic ethyl dimethyl betaine-methacrylic ethyl trimethylammonium chloride-methoxy polyethylene glycol methacrylate copolymer (DMA / PMMP / betaine): Plascize L-440W (Huying Chemical Industry Co., Ltd.) (Polytetramethylammonium-49) (also known as "DMA / PMMP / betaine"), Mw=N / A Methacrylethyl dimethyl betaine-methacrylyl ethyl trimethylammonium chloride-2-hydroxyethyl methacrylate copolymer (DMA / HEMA / betaine): Plascize L-450W (Huying Chemical Industry Co., Ltd.) (Polytetramethylammonium-48) (also known as "DMA / HEMA / betaine"), Mw=N / A Vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate copolymer diethyl sulfate (DMA / VP):HC polymer 1S(M) (Osaka Organic Chemicals Co., Ltd.) (Polytetraammonium-11), Mw=500,000 (also known as "DMA / VP1") Vinylpyrrolidone / N,N-dimethylaminoethyl methacrylate copolymer diethyl sulfate (DMA / VP):HC polymer 5W (Osaka Organic Chemicals Co., Ltd.) (polytetraammonium-11), Mw=150,000 (also known as "DMA / VP2") Polyvinyl alcohol (PVA): JMR-10HH (JAPAN VAM & POVAL Co., Ltd.), Mw=10,000 (also known as "PVA") Polyvinylpyrrolidone (PVP): PITZCOL (registered trademark) K-30A (First Industrial Pharmaceutical Co., Ltd.), Mw=45,000 (also known as "PVP") Poly-ε-L-lysine: Poly epsilon L-lysine HCl (Carbosynth), Mw=4,000 (also known as "poly-ε-L-lysine") Polyglucosamine hydroxypropyltrimethylammonium chloride: MOISTCOAT PX (Katakura & Co-op Agri Co., Ltd.), Mw=N / A (also known as "Chitosan PX") L-Lysine: L-Lysine (Fujifilm and Koko Pure Chemical Industries, Ltd.), Mw=146 (also known as "L-Lysine") L-Arginine: L-(+)-Arginine (Fujifilm and Kazumitsu Pure Chemical Industries, Ltd.), Mw=174 (also known as "L-Arginine") Polyethyleneimine: EPOMIN (registered trademark) SP-003 (Nippon Shokubai Co., Ltd.), Mw=300 (also known as "PEI1") Polyethyleneimine: EPOMIN (registered trademark) SP-200 (Nippon Shokubai Co., Ltd.), Mw=10,000 (also known as "PEI2") Polyethyleneimine: EPOMIN (registered trademark) P-1000 (Nippon Shokubai Co., Ltd.), Mw=70,000 (also known as "PEI3").

[0176] [(B) Component] Ammonium acetate (Kanto Chemical Co., Ltd.), molecular weight = 77 Diammonium hydrogen phosphate (Fujifilm and Koko Pure Chemical Industries Co., Ltd.), molecular weight = 132 Ammonium bicarbonate (Fujifilm and Koko Pure Chemical Industries Co., Ltd.), molecular weight = 79.

[0177] pH adjuster Ammonia: EL ammonia solution (concentration: 28.0%~30.0% (calculated as NH3) (Kanto Chemical Co., Ltd.), molecular weight = 17 Potassium hydroxide: 48% aqueous solution of potassium hydroxide (KOHLM (Kanto Chemical Co., Ltd.), molecular weight = 56) Sodium hydroxide: 25% sodium hydroxide aqueous solution (Yuchen Store Co., Ltd.), molecular weight = 40.

[0178] (A) The weight-average molecular weight (Mw) of the component was determined by the following method.

[0179] [Determination of weight-average molecular weight (Mw)] (A) The weight-average molecular weight (Mw) of the component is the value of the weight-average molecular weight (converted to polyethylene glycol) determined by gel permeation chromatography (GPC). The weight-average molecular weight was determined using the following apparatus and conditions: GPC device: Manufactured by Shimadzu Corporation Model: Prominence+ELSD (Evaporative Light Scattering Detector) Detector (ELSD-LTII) Tube Column: VP-ODS (manufactured by Shimadzu Corporation) Mobile phase A: MeOH B: 1% aqueous solution of acetic acid Flow rate: 1 mL / min Detector: ELSD temperature 40℃, gain 8, nitrogen 350 kPa Oven temperature: 40℃ Injection volume: 40 μL.

[0180] [Determination of pH value of surface treatment composition] The pH value of the surface treatment composition (liquid temperature: 25°C) was confirmed using a pH meter (manufactured by Horiba Manufacturing Co., Ltd., product name: LAQUA (registered trademark)).

[0181] [Preparation of Surface Treatment Compositions] (Example 1) The surface treatment composition 1 was prepared by mixing dimethyl diallyl ammonium chloride / acrylic acid copolymer (Merquat TM295 polymer: DADMAC / AA) as component (A), ammonium acetate as component (B), ammonia as a pH adjuster, and distilled water at 25°C for 5 minutes.

[0182] Here, the content of component (A) is set to 0.1% by mass relative to the total amount of surface treatment composition 1, the content of component (B) is set to 0.25% by mass relative to the total amount of surface treatment composition 1, and the content of the pH adjuster is set to the amount at which the pH of surface treatment composition 1 is 9.0. Surface treatment composition 1 does not contain abrasive particles (abrasive particle content = 0% by mass).

[0183] (Examples 2-16, Comparative Examples 1-14) Except for changing the types and contents of components (A), (B), and the pH adjuster as described in Table 1 below, surface treatment compositions 2-16 and comparative surface treatment compositions 1-14 were prepared in the same manner as in Example 1. Surface treatment compositions 2-16 and comparative surface treatment compositions 1-14 do not contain abrasive particles (abrasive particle content = 0% by mass).

[0184] [Table 1-1] Table 1 (A)Ingredients (B) Ingredients (A) Component / (B) Component Content Ratio pH adjuster pH value compound molecular weight content quality% Ionicity buffer content quality% Example 1 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 2 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 potassium hydroxide 9.0 Example 3 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 Sodium hydroxide 9.0 Example 4 DADMAC / Aam 1,600,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 5 DADMAC1 Less than 20,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 6 DADMAC2 20,000-100,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 7 DADMAC3 100,000 - 500,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 8 DCDA / DETA Less than 20,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 9 DMA / PMMP / Betaine N / A 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 10 DMA / HEMA / Betaine N / A 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 11 DMA / VP1 500,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 12 DMA / VP2 150,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Example 13 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 8.0 Example 14 DADMAC1 Less than 20,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 8.0 Example 15 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 10.0 Example 16 DADMAC1 Less than 20,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 10.0

[0185] [Table 1-2] Table 1 (continued) (A)Ingredients (B) Ingredients (A) Component / (B) Component Content Ratio pH adjuster pH value compound molecular weight content quality% Ionicity buffer content quality% Comparative Example 1 DADMAC / AA 190,000 0.1 cation - - - ammonia 9.0 Comparative Example 2 DADMAC / AA 190,000 0.1 cation Diammonium hydrogen phosphate 0.2 0.5 ammonia 9.0 Comparative Example 3 DADMAC / AA 190,000 0.1 cation ammonium bicarbonate 0.23 0.4 ammonia 9.0 Comparative Example 4 DADMAC / AA 190,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 7.5 Comparative Example 5 DADMAC1 Less than 20,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 7.5 Comparative Example 6 PVA 10,000 0.1 nonionic ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 7 PVP 45,000 0.1 nonionic ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 8 Poly-ε-L-lysine 4000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 9 Polyglucosamine PX N / A 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 10 L-lysine 146 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 11 L-arginine 174 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 12 PEI1 300 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 13 PEI2 10,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0 Comparative Example 14 PEI3 70,000 0.1 cation ammonium acetate 0.25 0.4 ammonia 9.0

[0186] [Preparation of the object to be ground] Prepare the polished object (polished SiN substrate, polished polycrystalline Si substrate) after polishing by the following chemical mechanical polishing (CMP) steps.

[0187] (CMP steps) As the objects to be ground, the following were prepared: a silicon wafer (SiN substrate) (300 mm unpatterned wafer, manufactured by Advance Materials Technology Co., Ltd.), on which a SiN film with a thickness of 2500 Å was formed on the surface by CVD (Chemical Vapor Deposition); and a silicon wafer (polycrystalline Si substrate) (300 mm wafer, manufactured by Advance Materials Technology Co., Ltd.), on which a polycrystalline silicon film with a thickness of 5000 Å was formed on the surface by CVD.

[0188] The SiN substrate and polycrystalline Si substrate prepared above are polished under the following conditions using a polishing composition with the following composition to obtain polished objects (polished SiN substrate and polished polycrystalline Si substrate).

[0189] <Grinding Composition> A silica slurry (composition: 10% by mass of colloidal silica (average primary particle size: 35 nm, average secondary particle size: 70 nm), 0.25% by mass of polyvinylpyrrolidone (PITZCOL (registered trademark) K-30A, Daiichi Kogyo Pharmaceutical Co., Ltd., Mw=45,000), 0.33% by mass of EL ammonia water (concentration: 28.0%~30.0% (calculated as NH3) (Kanto Chemical Co., Ltd.), solvent: distilled water) was prepared. The silica slurry was diluted 5 times with distilled water to prepare a grinding composition. The pH of the obtained grinding composition was 10.0.

[0190] <Grinding equipment and grinding conditions> Grinding device: FREX300E manufactured by Ebara Manufacturing Co., Ltd. Abrasive pads: Foamed polyurethane pads manufactured by FUJIBO HOLDINGS Co., Ltd. H800-Type1 Adjuster (trimmer): Nylon brush (manufactured by 3M) Grinding pressure: 2.0 psi (1 psi = 6894.76 Pa, the same below) Grinding platen speed: 80 rpm Grinding head speed: 80 rpm Supply of grinding composition: pouring Grinding composition supply rate: 200 mL / min Grinding time: 30 seconds.

[0191] [Rinse and grind] In the CMP steps described above, the surfaces of the objects to be polished (SiN substrate and polycrystalline Si substrate) are polished respectively, and then the polished objects (polished SiN substrate and polished polycrystalline Si substrate) are removed from the polishing plate. Next, in the same polishing apparatus, the polished objects are mounted on another polishing plate, and under the following conditions, the surface treatment compositions prepared in Examples 1-16 and Comparative Examples 1-14 are used to perform a rinsing and polishing treatment on the surface of the polished objects.

[0192] <Purification and Grinding Equipment and Conditions> Grinding device: FREX300E manufactured by Ebara Manufacturing Co., Ltd. Abrasive pads: Foamed polyurethane pads manufactured by FUJIBO HOLDINGS Co., Ltd. H800-Type1 Adjuster (trimmer): Nylon brush (manufactured by 3M) Grinding pressure: 1.0 psi Press plate speed: 80 rpm Grinding head speed: 80 rpm Supply of grinding composition: pouring Surface treatment composition supply rate: 300 mL / min Grinding time: 60 seconds.

[0193] [Post-washing treatment] After rinsing and polishing, the substrate surface was brushed clean for 20 seconds using a 0.3% NH3 aqueous solution, and then rinsed with deionized water for 40 seconds to obtain the rinsed and polished objects (SiN substrates 1-16 rinsed and polished using surface treatment compositions 1-16 of Examples 1-16, SiN substrates 1-14 rinsed and polished using comparative surface treatment compositions 1-14 of Comparative Examples 1-14, polycrystalline Si substrates 1-16 rinsed and polished using surface treatment compositions 1-16 of Examples 1-16, and polycrystalline Si substrates 1-14 rinsed and polished using comparative surface treatment compositions 1-14 of Comparative Examples 1-14).

[0194] [evaluate] (Residue Evaluation) Under alkaline conditions, a large number of hydroxyl groups exist on the surface of polycrystalline Si substrates, forming a water film on the surface. Therefore, defects (such as abrasive residues, pad shavings, or organic residues such as polymers) are difficult to adhere to or do not adhere to the surface of polycrystalline Si substrates. On the other hand, defects (such as abrasive residues, pad shavings, or organic residues such as polymers) easily adhere to SiN substrates. Therefore, in this evaluation, the number of abrasive residues and the number of organic residues (pad shavings, polymers, etc.) on a washed and polished SiN substrate (SiN substrate after washing and polishing treatment) were measured according to the following method. The results are shown in Table 2 below ("Number of Defects on SiN" in the table).

[0195] The number of residues on the surface of a rinsed and polished SiN substrate (a polished SiN substrate after rinse and polishing) was evaluated using a Surfscan SP5 optical inspection machine (registered trademark) manufactured by KLA-Tencor Co., Ltd. Specifically, the number of residues with a diameter greater than 50 nm was counted in the remaining portion (the area from 0 mm to 5 mm when the outer perimeter is set to 0 mm) on one side of the rinsed and polished SiN substrate. Subsequently, the number of abrasive particle residues and organic residues was determined by SEM observation using a Review SEM RS6000 manufactured by Hitachi Advanced Technology Co., Ltd. First, 100 samples of residues present in the remaining portion (excluding the 5 mm width portion removed) on one side of the rinsed and polished SiN substrate were taken by SEM observation. Subsequently, from the 100 samples of residue, the type of residue (abrasive particles or organic residue) was determined by visual SEM observation. The number of abrasive particle residues (SiO2 residue) and organic residues (pads or polymers, etc.) was measured separately. Furthermore, the number of abrasive particle residues (SiO2 residue) should preferably be as low as possible; 30 or less is acceptable, 25 or less is preferred, and less than 20 is even better. The number of organic residues (pads or polymers, etc.) should also preferably be as low as possible; less than 15 is acceptable, 10 or less is preferred, and less than 5 is even better.

[0196] (Evaluation of the zeta potential of abrasive particles) The zeta potential of the abrasive particles (colloidal silicon dioxide, SiO2) in each surface treatment composition was determined according to the following method. The results are shown in Table 2 below ("Zetta potential of abrasive particles [mV]" in the table).

[0197] The zeta potential of the abrasive particles was measured using a Zetasizer Nano ZSP manufactured by Spectris Inc. (Malvern Business Division). The zeta potential of the abrasive particles during rinsing and polishing with a surface treatment composition was set to the value measured in the model experiment described below.

[0198] In each surface treatment composition, a silica (SiO2) particle dispersion (colloidal silica, average primary particle size: 35 nm, average secondary particle size: 70 nm, 19.5% by mass aqueous dispersion) was added to prepare a test solution with a silica particle concentration of 0.02% by mass (the content (concentration) of silica particles in the test solution relative to the total mass of the test solution is 0.02% by mass). The obtained test solution was filled into the dedicated test cell of the above-mentioned apparatus (Zetasizer Nano ZSP), and the zeta potential (mV) of the abrasive particles was measured. A zeta potential (mV) of 30 mV or higher for the abrasive particles is acceptable.

[0199] (Evaluation of zeta potential of SiN substrate and pad) The zeta potentials of silicon nitride (SiN substrate) and padding material (polyurethane) in each surface treatment composition were measured. The results are shown in Table 2 below ("Zeta potential SiN [mV]" and "Zeta potential padding material [mV]"). Furthermore, it is speculated that the zeta potential of silicon nitride has a greater impact on the residue removal effect compared to that of polycrystalline silicon. Therefore, in this evaluation, the zeta potential of the SiN substrate in the surface treatment composition was measured.

[0200] The zeta potential of the polished SiN substrate and the zeta potential of the pad debris were measured using a SurPASS3 solid-state zeta potential meter manufactured by Anton Paar Japan Co., Ltd. The zeta potential of the polished SiN substrate surface during rinsing and polishing with the surface treatment composition, and the zeta potential of the pad debris during rinsing and polishing with the surface treatment composition, were measured in the model experiments described below.

[0201] The zeta potential of the polished SiN substrate surface was measured using a silicon wafer (SiN substrate) (300 mm unpatterned wafer, manufactured by Advantec Corporation) cut into 60 mm square pieces as the measurement object. The silicon wafer had a SiN film with a thickness of 2500 Å formed on its surface by CVD.

[0202] The zeta potential of the pad was measured using a 60 mm square piece of polyurethane pad (manufactured by FUJIBO HOLDINGS Co., Ltd., foamed polyurethane pad, H800-Type1) as the test object.

[0203] The test objects are each placed in a zeta potentiometer. Then, the surface treatment composition prepared above is passed into the test objects, and the zeta potential (mV) of each test object is measured. A zeta potential (mV) of 30 mV or higher for both the SiN substrate and the pad is acceptable.

[0204] (Etching rate evaluation) The etching rates of SiN substrates polished using the rinsing and polishing processes of each surface treatment composition, and the etching rates of polycrystalline Si substrates polished using the rinsing and polishing processes of each surface treatment composition, were set as values ​​measured in the model experiments described below. These values ​​are shown in Table 2 below ("SiN [Å / min]" and "Polycrystalline Si [Å / min]" in the table).

[0205] The etching rate of the polished SiN substrate was measured using a silicon wafer (SiN substrate) (300 mm unpatterned wafer, manufactured by Advantec Corporation) cut into 60 mm square pieces as the measurement object. The silicon wafer had a SiN film with a thickness of 2500 Å formed on its surface by CVD.

[0206] The etching rate of the polished polycrystalline Si substrate was measured using a silicon wafer (polycrystalline Si substrate) (300 mm, manufactured by Advance Materials Technology Co., Ltd.) cut into 60 mm square pieces as the measurement object. The silicon wafer had a polycrystalline silicon film with a thickness of 5000 Å formed on its surface by CVD.

[0207] The thickness of the test objects (thickness before immersion (Å)) was measured using an optical film thickness gauge (Lambda ACE VM-2030: manufactured by Dai Nippon Screen Manufacturing Co., Ltd.). Next, the test objects were immersed in the surface treatment composition prepared above for 30 minutes. The thickness of the test objects after immersion for the specified time (thickness after immersion (Å)) was measured using the optical film thickness gauge (Lambda ACE VM-2030: manufactured by Dai Nippon Screen Manufacturing Co., Ltd.). The etching rate [=(thickness before immersion (Å) - thickness after immersion (Å)) / immersion time (min)] was calculated by dividing the difference in thickness before and after immersion by the immersion time (min). Furthermore, the etching rate of the polished polycrystalline Si substrate and the polished SiN substrate should preferably be as low as possible; it is acceptable if it does not reach 15 Å / min, preferably not more than 10 Å / min, and even more preferably less than 5 Å / min.

[0208] (ΔpH value evaluation) The difference in pH value (ΔpH value) between the surface treatment composition before and after rinsing and polishing the SiN substrate to be polished is measured [= (pH value of the surface treatment composition after rinsing and polishing) - (pH value of the surface treatment composition before rinsing and polishing)]. Furthermore, the pH value of the surface treatment composition before rinsing and polishing is the pH value of the surface treatment composition described in Table 1 above. This value is shown in Table 2 below ("ΔpH value [-]" in the table). Furthermore, the ΔpH value (pH change before and after rinsing and polishing) is preferably as small as possible; it is acceptable if it does not reach 1.0, preferably not reaching 0.8, and more preferably not reaching 0.3.

[0209] [Table 2-1] Table 2 ζ potential Number of defects on SiN ∆pH value [-] Etching rate SiN[mV] Abrasive particles [mV] Pad debris [mV] Abrasive particle residue [count] Organic residue [count] Polycrystalline Si [Å / min] SiN [Å / min] Example 1 57 51 40 15 2 0 1 0 Example 2 35 38 30 twenty one 10 0.8 10 0 Example 3 33 39 29 20 10 0.8 11 0 Example 4 36 35 38 18 5 0 1 0 Example 5 35 38 35 twenty three 3 0 3 0 Example 6 39 45 40 28 7 0 5 0 Example 7 45 48 49 29 8 0 3 0 Example 8 37 36 35 29 8 0 5 0 Example 9 35 38 39 28 6 0 5 0 Example 10 35 36 35 27 9 0 6 0 Example 11 35 37 35 29 8 0 2 0 Example 12 36 35 37 28 9 0 2 0 Example 13 50 51 33 20 4 0 0 0 Example 14 36 32 37 27 3 0 2 0 Example 15 52 50 40 17 3 0 7 0 Example 16 34 30 35 26 5 0 7 0

[0210] [Table 2-2] Table 2 (continued) ζ potential Number of defects on SiN ∆pH value [-] Etching rate SiN [mV] abrasive particles [mV] padding [mV] Abrasive particle residue [count] Organic residue [count] Polycrystalline Si [Å / min] SiN [Å / min] Comparative Example 1 twenty two twenty three twenty one 33 15 1.2 29 0 Comparative Example 2 twenty five twenty five twenty four 32 15 0.8 16 0 Comparative Example 3 twenty three 27 twenty five 33 16 0.8 17 0 Comparative Example 4 19 17 18 53 twenty three 0 0 0 Comparative Example 5 18 20 19 57 twenty five 0 0 0 Comparative Example 6 -40 -51 -34 87 13 0 15 0 Comparative Example 7 -38 -48 -30 79 16 0 16 0 Comparative Example 8 -12 -30 -28 66 34 0 15 0 Comparative Example 9 -15 -31 -27 68 32 0 16 0 Comparative Example 10 -46 -42 -43 79 twenty one 0 16 0 Comparative Example 11 -48 -48 -45 89 11 0 18 0 Comparative Example 12 -5 -16 -9 79 twenty one 0 15 0 Comparative Example 13 46 36 35 50 26 0 15 0 Comparative Example 14 50 40 42 54 28 0 16 0

[0211] As clearly shown in Table 2 above, the surface treatment composition according to the embodiments can more effectively remove residues from the SiN substrate compared to the surface treatment composition of the comparative examples. Furthermore, the surface treatment composition according to the embodiments can suppress the etching rate of the polycrystalline Si substrate to a lower level. The above results were obtained immediately after the surface treatment composition was manufactured; however, in cases of long-term storage or preservation, it is preferable to include an antifungal agent (preservative). Moreover, the antifungal agent (preservative) has little or no effect on the above results; therefore, it has been found that surface treatment compositions containing an antifungal agent (preservative) also yield the same results as described above.

[0212] Furthermore, Table 2 above shows the difference in pH value of the surface treatment composition before and after rinsing and polishing the SiN substrate to be polished. The difference in pH value of the surface treatment composition before and after rinsing and polishing the polycrystalline Si substrate or TEOS film to be polished is the same as the difference in pH value of the surface treatment composition before and after rinsing and polishing the SiN substrate to be polished. This application is based on Japanese Patent Application No. 2022-053009, filed on March 29, 2022, the disclosure of which is referenced and incorporated herein by reference in its entirety.

Claims

1. A surface treatment composition comprising the following components (A) and (B), and having a pH value of 8.0 or higher: (A) Component: A polymer containing a structural unit having a quaternary nitrogen-containing onium salt or a structural unit of the following structure (X): [Chemical 1] In the above structure (X), R31 to R34 each independently represent a hydrogen atom or a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms; (B) Component: A buffer represented by the formula: R-COO-NH4+ (R is a straight-chain or branched alkyl group or phenyl group having 1 or more but less than 10 carbon atoms).

2. The surface treatment composition of claim 1, wherein the above-mentioned component (A) comprises a polymer containing structural units having a quaternary nitrogen-containing onium salt.

3. The surface treatment composition of claim 1, wherein the above-mentioned structural unit having a quaternary nitrogen-containing onium salt is only the following structure (Y) or the following structure (Z): [Chemical 2] In the above structure (Y), R11 represents a hydrogen atom or a methyl group, R12 represents a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms, R13 to R15 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms, and X1 represents an anionic portion; [Chemical 3] In the above structure (Z), R21 and R22 each independently represent a hydrogen atom, an alkyl group having 1 or more but less than 3 carbon atoms, or a phenyl group, R23 and R24 each independently represent a straight-chain or branched alkyl group having 1 or more but less than 10 carbon atoms, and X2 represents an anionic portion.

4. The surface treatment composition of claim 1 does not substantially contain abrasive particles.

5. The surface treatment composition of claim 1, wherein the polymer is contained in the surface treatment composition at a ratio of more than 0.05% by mass.

6. The surface treatment composition of claim 1, wherein the content ratio of component (A) to component (B) is 0.1 or more and 1.5 or less by mass.

7. The surface treatment composition of claim 1, wherein the buffer is ammonium acetate.

8. The surface treatment composition of claim 1 further comprises component (C): component (C): pH adjuster.

9. The surface treatment composition of claim 8, wherein the pH adjuster is ammonia.

10. A surface treatment method comprising using a surface treatment composition as claimed in any one of claims 1 to 9 to surface treat a polished abrasive object comprising at least one of the group consisting of silicon nitride, silicon oxide, and polycrystalline silicon, thereby reducing residue on the surface of the polished abrasive object.

11. The surface treatment method as described in claim 10 is a rinsing and grinding method or a washing method.

12. A method for manufacturing a semiconductor substrate, wherein the polished object is a polished semiconductor substrate, the method comprising the following steps: a polishing step, wherein a pre-polishing semiconductor substrate comprising at least one of silicon nitride, silicon oxide, and polycrystalline silicon is polished using a polishing composition comprising abrasive particles to obtain a polished semiconductor substrate; and a surface treatment step, wherein a surface treatment composition as claimed in any one of claims 1 to 9 is used to reduce residues containing the abrasive particles on the surface of the polished semiconductor substrate.

13. The method for manufacturing a semiconductor substrate as claimed in claim 12, wherein the pH value of the polishing composition is 8.5 or higher.