Polishing composition and copolymer

Abstract

The present invention pertains to a polishing composition comprising an aqueous medium, abrasive grains, and a copolymer at least having: a structural unit (A) represented by formula (A) [in formula (A), X1 represents -N(-H)- or -O-, R1-R5 each independently represent a hydrogen atom or -OH, at least two adjacent ones of R1-R5 represent -OH, R6 represents a linear or branched alkylene group or alkenylene group optionally having a substituent and having 1-7 carbon atoms, one or more -CH2- included in the alkylene group or alkenylene group are each optionally substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-, and R7 represents a hydrogen atom or a methyl group]; and a structural unit (B) having a hydrophilic structure.

Description

Polishing compositions and copolymers

[0001] This invention relates to abrasive compositions and copolymers.

[0002] In the semiconductor manufacturing process, a polishing process is performed to improve the flatness of the wafer surface. In particular, the CMP (chemical mechanical polishing) process, which enables high-precision polishing, has become an essential process in semiconductor manufacturing.

[0003] The CMP process typically involves supplying an abrasive composition containing abrasive particles, pressing a wafer held by a top ring against a polishing pad, and rotating the top ring and polishing pad to polish the wafer surface to a flat surface. The polishing composition used in the CMP process is also called a CMP slurry.

[0004] Various studies have been conducted on polishing compositions used in the CMP process. For example, Patent Documents 1 to 7 describe polishing liquid compositions containing cerium oxide particles, a specific water-soluble polymer compound, and an aqueous medium such as water. Patent Document 8 describes a method for manufacturing silicon wafers that includes a polishing step using a polishing liquid composition containing silica particles, a specific water-soluble polymer, a nitrogen-containing basic compound, and an aqueous medium, along with other steps.

[0005] Japanese Patent Publication No. 2019-121641, Japanese Patent Publication No. 2020-186367, Japanese Patent Publication No. 2021-166254, Japanese Patent Publication No. 2021-100126, Japanese Patent Publication No. 2021-5631, Japanese Patent Publication No. 2021-5704, Japanese Patent Publication No. 2009-260236, Japanese Patent Publication No. 2019-186346

[0006] As described above, various polishing compositions have been investigated, but there is a need to improve the planarization effect after polishing.

[0007] Therefore, the present invention aims to provide an abrasive composition having improved planarization ability.

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by a polishing composition containing a copolymer having a specific structural unit, abrasive grains, and an aqueous medium, and have completed the present invention. That is, the present invention includes the following aspects. [1] Formula (A): [In formula (A), X １ represents -N(-H)- or -O-, and R １ to R ５ each independently represents a hydrogen atom or -OH, provided that at least two adjacent ones of R １ to R ５ represent -OH, and R ６ represents a linear or branched alkylene group or alkenylene group having 1 to 7 carbon atoms which may have a substituent, and one or more -CH ２ - contained in the alkylene group or alkenylene group may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)- or -C(=O)-, and R ７ represents a hydrogen atom or a methyl group] A polishing composition comprising a copolymer having at least a structural unit (A) represented by and a structural unit (B) having a hydrophilic structure, abrasive grains, and an aqueous medium. [2] The polishing composition according to [1], wherein the weight average molecular weight of the copolymer is 1,000 to 1,000,000. [3] The polishing composition according to [1] or [2], wherein the hydrophilic structure is at least one structure selected from the group consisting of a cation structure, an anion structure, a betaine structure, an amide structure, an alkylene oxide structure, a hydroxyl group-containing structure, a lactam structure, and an amine structure. [4] The polishing composition according to any one of [1] to [3], wherein the hydrophilic structure includes a betaine structure having at least one atom selected from the group consisting of a quaternary nitrogen atom having a positive charge, a tertiary sulfur atom having a positive charge, and a quaternary phosphorus atom having a positive charge. [5] The betaine structure is represented by formula (1-1): [In the formula, R ８ represents a linear or branched alkylene group having 1 to 6 carbon atoms, and R ９ and R １０ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, and R１１ represents a single bond, a linear or branched alkylene group with 1 to 4 carbon atoms, and Y is -O － , -SO ３ － or -COO － The polishing composition according to [4], represented by [A], where * represents a bond. [6] The polishing composition according to any one of [1] to [5], wherein the amount of constituent unit (A) represented by formula (A) in the copolymer is 0.01 to 50% by mass relative to the total amount of constituent units of the copolymer. [7] The polishing composition according to any one of [1] to [6], wherein the amount of the copolymer contained in the polishing composition is 0.0001 to 6% by mass based on the total weight of the polishing composition. [8] The polishing composition according to any one of [1] to [7], wherein the abrasive grains are silica particles and / or ceria particles. [9] Formula (A): [In formula (A), X １ represents -N(-H)- or -O-, and R １ ~R ５ Each of these independently represents a hydrogen atom or -OH, except R １ ~R ５ At least two adjacent ones among them represent -OH, R ６ represents a linear or branched alkylene or alkenylene group having 1 to 7 carbon atoms, which may have substituents, and contains one or more -CH groups. ２ The - may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-, R ７ A copolymer having at least one constituent unit (A) represented by [wherein it represents a hydrogen atom or a methyl group] and one constituent unit (B) having a hydrophilic structure.

[0009] According to the present invention, it is possible to provide a polishing composition in which the planarization effect after polishing is improved.

[0010] Embodiments of the present invention will be described in detail below. However, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the invention. In this specification, the range of numerical values ​​indicated by "~" includes its upper and lower limits.

[0011] [Copolymer] The abrasive composition of the present invention is of formula (A): [In formula (A), X １ represents -N(-H)- or -O-, and R １ ~R ５ Each of these independently represents a hydrogen atom or -OH, except R １ ~R ５ At least two adjacent ones among them represent -OH, R ６ represents a linear or branched alkylene or alkenylene group having 1 to 7 carbon atoms, which may have substituents, and contains one or more -CH groups. ２ The - may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-, R ７ The abrasive composition comprises a copolymer having at least one constituent unit (A) represented by [a hydrogen atom or a methyl group] and one constituent unit (B) having a hydrophilic structure, abrasive grains, and an aqueous medium. In this specification, the copolymer included in the abrasive composition may be a polymer containing one type of constituent unit (A) and one type of constituent unit (B), or a polymer containing two or more types of constituent units (A) and two or more types of constituent units (B), or a polymer containing one or more types of constituent units (A) and one or more types of constituent units (B).

[0012] X in equation (A) １ This represents -N(-H)- or -O-. １ From the viewpoint of the copolymer's hydrolysis resistance, it is preferably -N(-H)-.

[0013] R １ ~R ５ Each of these independently represents a hydrogen atom or -OH, except R １ ~R ５At least two of these adjacent ones represent -OH. From the viewpoint of improving the planarization effect, R １ ~R ５ Of these, R ２ and R ３ represents -OH, R １ 、 R ４ and R ５ It is preferable that R represents a hydrogen atom or an -OH group. ２ and R ３ represents -OH, R １ 、 R ４ and R ５ It is more preferable that represents a hydrogen atom.

[0014] R ６ represents a linear or branched alkylene or alkenylene group having 1 to 7 carbon atoms, which may have substituents, and contains one or more -CH groups. ２ The - symbol may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-.

[0015] Examples of linear or branched alkylene groups having 1 to 7 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, methylmethylene group, methylethylene group, dimethylethylene group, methylpropylene group, ethylpropylene group, dimethylpropylene group, methylbutylene group, n-pentylene group, n-hexylene group, and n-heptylene group.

[0016] As a linear or branched alkenylene group having 1 to 7 carbon atoms, at least one -CH group in the linear or branched alkylene group described above ２ -CH ２ One example is a group in which the - group is replaced by -CH=CH-.

[0017] One or more -CH groups contained within a linear or branched alkylene group having 1 to 7 carbon atoms ２Groups in which - is substituted with -O-, -C(=O)-O-, -CH(-OH)-, -C(=O)-, or -O-C(=O)- include, specifically, ether groups, ester groups, hydroxymethyl groups, ketone groups, etc. In this case, one or more -CH groups may be present. ２ The number of carbon atoms after the - is replaced with -O- etc. should be between 1 and 7.

[0018] One or more -CH groups contained within a linear or branched alkenylene group having 1 to 7 carbon atoms ２ Groups in which - is substituted with -O-, -C(=O)-O-, -CH(-OH)-, -C(=O)-, or -O-C(=O)- include, specifically, ether groups, ester groups, hydroxymethyl groups, ketone groups, etc. In this case, one or more -CH groups may be present. ２ The number of carbon atoms after the - is replaced with -O- etc. should be between 1 and 7.

[0019] R ６ The number of carbon atoms is preferably 2 to 5, more preferably 2 to 4, from the viewpoint of solubility in aqueous media and ease of availability.

[0020] R ７ represents a hydrogen atom or a methyl group.

[0021] The hydrophilic structural unit (B) is a structural unit derived from a monomer having a hydrophilic structure. Examples of hydrophilic structures include cationic structures, anionic structures, betaine structures, amide structures, alkylene oxide structures, hydroxyl group-containing structures, lactam structures, and amine structures. From the viewpoint of improving the planarization effect and improving water solubility, the hydrophilic structure is preferably at least one structure selected from the group consisting of cationic structures, anionic structures, betaine structures, amide structures, alkylene oxide structures, hydroxyl group-containing structures, and lactam structures. From the viewpoint of improving the planarization effect, the structural unit (B) is preferably electrically neutral or cationic, and more preferably electrically neutral. Note that the electrically neutral nature of structural unit (B) means that the sum of the cationic charge and anionic charge in structural unit (B) is zero.

[0022] The copolymer of the present invention may have one type of constituent unit (B) having a hydrophilic structure, or it may have two or more types of constituent units (B).

[0023] A cationic structure is a structure having a positively charged, electrically cationic side chain. Examples of cationic structures include structures containing a positively charged quaternary nitrogen atom, and in particular structures containing a quaternary ammonium cation. Examples of monomers having a cationic structure include N-[3-(dimethylamino)propyl]acrylamide-methyl quaternary salt, 2-dimethylaminoethyl (meth)acrylate-methyl quaternary salt, monomers containing a tertiary amine such as 2-dimethylaminoethyl (meth)acrylate, N-(2-dimethylaminoethyl)(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, 1-vinylimidazole, 2-vinylpyridine, and 4-vinylpyridine, obtained by reacting these with iodomethane, methyl chloride, dimethyl sulfate, diethyl sulfate, etc. The cationic structure in the copolymer may be obtained by copolymerizing monomers having a cationic structure, or by copolymerizing monomers without a cationic structure and reacting the side chain in this copolymer with the above-mentioned compounds.

[0024] An anionic structure is a structure having a negatively charged, electrically anionic side chain. Examples of anionic structures include structures containing sulfinite groups, sulfate groups, sulfonate groups, carboxylate groups, phosphate groups, and phosphonate groups. Examples of monomers having anionic structures include acrylic acid, methacrylic acid, itaconic acid, maleic acid, vinyl phosphoric acid, vinylphosphonic acid, styrenesulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid. Monomers having anionic structures may have their anionic structures neutralized with bases such as ammonia, ammonium hydroxide, and sodium hydroxide.

[0025] A betaine structure is a structure in which a positive charge and a negative charge exist within the same molecule, and the positively charged atom does not have any dissociable hydrogen atoms bonded to it, resulting in an overall neutral (chargeless) structure. Preferably, the betaine structure has positive and negative charges at non-adjacent positions within the same molecule. In a betaine structure, the positively charged functional group can be, for example, a quaternary ammonium, a tertiary sulfonium, or a quaternary phosphonium, and the negatively charged functional group can be, for example, a sulfonic acid, a carboxylic acid, or a phosphonic acid. The positively and negatively charged functional groups may also be amine oxides. That is, a betaine structure can be, for example, sulfobetaine, carboxybetaine, phosphobetaine, or an amine oxide.

[0026] An amide structure is a structure having -C(=O)-NH-, and an example is the (meth)acrylamide structure having a (meth)acrylic group. Examples of monomers having an amide structure include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-(meth)acrylmorpholide, N-methoxymethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-monomethyl(meth)acrylamide, and N-monoethyl(meth)acrylamide.

[0027] An alkylene oxide structure is a structure in which some of the carbon atoms forming an alkyl chain are replaced by oxygen. Specific examples of monomers having an alkylene oxide structure include ethylene glycol, methoxyethylene glycol, ethoxyethylene glycol, 2-propylene glycol, 2-methoxypropylene glycol, 2-ethoxypropylene glycol, 3-propylene glycol, 3-methoxypropylene glycol, 3-ethoxypropylene glycol, 2-butylene glycol, 3-butylene glycol, 4-butylene glycol, polyethylene glycol, methoxypolyethylene glycol, polypropylene glycol, methoxypolypropylene glycol, and polybutylene glycol. Other specific examples of monomers having an alkylene oxide structure include those having a (meth)acrylic group, such as polyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, 2-hydroxyethyl vinyl ether, and glycerin monomethacrylate.

[0028] A hydroxyl group-containing structure is a structure having a hydroxyl group (-OH group) in its side chain. Examples include structures in which part of the above and below structures is substituted with a hydroxyl group, and alcohol structures containing a side chain with a -OH group at its terminus. Specific examples of monomers having an alcohol structure include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and glycerin monomethacrylate.

[0029] A lactam structure is a ring formed by the dehydration condensation of a carboxyl group and an amino group. Examples include α-lactam (three-membered ring), β-lactam (four-membered ring), γ-lactam (five-membered ring), and δ-lactam (six-membered ring). Specific examples of monomers having a lactam structure include N-vinyl-2-caprolactam, N-vinylpyrrolidone, and N-vinylpiperidone.

[0030] An amine structure is a structure having an electrically neutral amino group side chain. Examples of amine structures include structures containing a tertiary nitrogen atom as a tertiary amine, a secondary nitrogen atom as a secondary amine, and a primary nitrogen atom as a primary amine. Examples of monomers having an amine structure include vinylamine, 1-vinylimidazole, 2-vinylpyridine, 4-vinylpyridine, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl (meth)acrylate, N-[3-(dimethylamino)propyl]acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, and allylamine.

[0031] In a preferred embodiment of the present invention, the hydrophilic structure may be a structure selected from the group consisting of (1) a betaine structure having at least one atom selected from the group consisting of a positively charged quaternary nitrogen atom, a positively charged tertiary sulfur atom, and a positively charged quaternary phosphorus atom; (2) a cation structure containing a positively charged quaternary nitrogen atom; (3) a structure having an amino group containing electrically neutral primary, secondary, and tertiary nitrogen atoms; (4) a lactam structure; and (5) a structure having a negatively charged side chain.

[0032] A betaine structure having a positively charged quaternary nitrogen atom is preferably of formula (1-1): [In the formula, R ８ R represents a linear or branched alkylene group having 1 to 6 carbon atoms. ９ and R １０ Each of these independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, and R １１ represents a single bond, a linear or branched alkylene group with 1 to 4 carbon atoms, and Y is -O － , -SO ３ － or -COO － This represents [a combination], and * represents a combination.

[0033] A betaine structure having a positively charged tertiary sulfur atom is preferably of formula (1-2): [In the formula, R ８ R represents a linear or branched alkylene group having 1 to 6 carbon atoms. ９represents a linear or branched alkyl group having 1 to 4 carbon atoms, and R １１ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, and Y represents -O － , -SO ３ － or -COO － represents, and * represents a bond]. It is represented by

[0034] The betaine structure having a quaternary phosphorus atom with a positive charge is preferably of the formula (1-3): [In the formula, R ８ represents a linear or branched alkylene group having 1 to 6 carbon atoms, R ９ and R １０ each independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, R １１ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, and Y represents -O － , -SO ３ － or -COO － represents, and * represents a bond]. It is represented by

[0035] In R ８ in the formulas (1-1), (1-2) and (1-3), examples of the linear or branched alkylene group having 1 to 6 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an isobutylene group, a methylmethylene group, a methylethylene group, a dimethylethylene group, a methylpropylene group, a methylbutylene group, a methylpentylene group and the like. From the viewpoint of easily improving hydrophilicity, R １ is preferably a linear or branched alkylene group having 1 to 4 carbon atoms, more preferably a linear or branched alkylene group having 1 to 3 carbon atoms.

[0036] In R ９ and R １０ in the formulas (1-1), (1-2) and (1-3), examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and the like. From the viewpoint of easily improving hydrophilicity, R ２is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.

[0037] In formulas (1-1), (1-2) and (1-3), R １１ Examples of the linear or branched alkylene group having 1 to 4 carbon atoms in include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, a methylmethylene group, a methylethylene group, a dimethylethylene group, a methylpropylene group and the like. From the viewpoint of easily improving hydrophilicity, R １１ is preferably an alkylene group having 1 to 3 carbon atoms, more preferably a methylene group or an ethylene group, and still more preferably a methylene group.

[0038] In formulas (1-1), (1-2) and (1-3), Y represents -O － , -SO ３ － or -COO － and preferably represents -COO － .

[0039] (2) The cationic structure containing a quaternary nitrogen atom having a positive charge is preferably represented by formula (2): [In the formula, R １２ represents a linear or branched alkylene group having 1 to 6 carbon atoms, and R １３ to R １５ each independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents a bond]. Examples of the linear or branched alkylene group having 1 to 6 carbon atoms and the linear or branched alkyl group having 1 to 4 carbon atoms include the groups described for formulas (1-1) to (1-3), and the preferred embodiments are the same.

[0040] (3) The structure having an amino group containing an electrically neutral primary, secondary or tertiary nitrogen atom is preferably represented by formula (3): [In the formula, R １６ represents a linear or branched alkylene group having 1 to 6 carbon atoms, and R １７ and R １８The terms are represented as follows: each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and * represents a bond. Examples of linear or branched alkylene groups having 1 to 6 carbon atoms and linear or branched alkyl groups having 1 to 4 carbon atoms include the groups described with respect to formulas (1-1) to (1-3), and the preferred embodiments apply similarly.

[0041] (4) The lactam structure is preferably of formula (4): [In the formula, n represents an integer from 1 to 5, and * represents a combination.]

[0042] (5) Structures having negatively charged side chains are preferably -SO ３ － Base or -COO － It is a structure that has a group and has a negative charge as a whole.

[0043] The reason why the present invention provides a polishing composition with improved planarization ability by including a copolymer having a constituent unit (A) represented by formula (A) and a constituent unit (B) having a hydrophilic structure is not limited to theory, but can be considered as follows: Because the constituent unit (A) represented by formula (A) has at least two -OH groups on adjacent carbon atoms on the benzene ring, this structure hydrogen bonds to the surface of the abrasive grains in the polishing composition, and the copolymer coats the abrasive grains. This is thought to alleviate the stress generated between the abrasive grains and the wafer surface during the polishing process, avoiding localized stress concentration on the wafer surface, improving the flatness of the substrate, and consequently lowering the Ra value of the wafer surface. Furthermore, because the constituent unit of formula (A) also has a benzene ring, which is a hydrophobic part, it is thought to have high adhesion to the silicon wafer or the other object to be polished. In this way, polishing is performed with the abrasive grains and the object to be polished in close contact, so that polishing progresses in the convex parts of the substrate, and polishing is made less likely to progress in the concave parts of the substrate due to the close contact between the substrate and the polymer, thus improving the planarization ability. Furthermore, the statement that the planarization effect is improved by the polishing composition of the present invention means that the planarization effect is improved when polishing is performed with a polishing composition containing a copolymer containing constituent unit (A) and constituent unit (B) compared to when polishing is performed with a polishing composition containing a polymer of constituent unit (A).

[0044] The present invention also provides copolymers having a constituent unit (A) represented by formula (A) and a constituent unit (B) having a hydrophilic structure. The description and preferred embodiments of copolymers having a constituent unit (A) represented by formula (A) and a constituent unit (B) having a hydrophilic structure included in the polishing composition of the present invention also apply to the copolymers of the present invention having a constituent unit (A) represented by formula (A) and a constituent unit (B) having a hydrophilic structure.

[0045] The content of the copolymer having a constituent unit (A) represented by formula (A) and a constituent unit (B) having a hydrophilic structure in the polishing composition of the present invention is preferably 0.0001 to 6% by mass, more preferably 0.0005 to 5% by mass, even more preferably 0.001 to 4% by mass, even more preferably 0.005 to 3% by mass, and particularly preferably 0.01 to 2% by mass, based on the total weight of the polishing composition, from the viewpoint of the planarization ability of the polishing composition and the storage stability of the polishing composition.

[0046] The copolymer contained in the polishing composition of the present invention may contain, in addition to the constituent unit (A) represented by formula (A) and the constituent unit (B) having a hydrophilic structure, other constituent units based on other monomers copolymerizable with the monomers that give these constituent units. Examples of other constituent units include constituent units corresponding to monomers having polymerizable sites such as vinyl groups and (meth)acryloyl groups, and examples of vinyl monomers such as vinyl alcohol and vinyl acetate, monomers such as acrylic acid esters, methacrylic acid esters, acrylonitrile, maleic acid esters, itaconic acid esters, vinyl methyl ethers, vinyl methyl oxazolidinone, vinyl formal, vinyl acetal, and vinyl isobutyl ether, monomers having these structures in part, and constituent units corresponding to oligomers in which these monomers or monomers having these structures in part are constituent units. When the copolymer has other constituent units in addition to the constituent unit (A) represented by formula (A) and the constituent unit (B) having a hydrophilic structure, there may be one type of other constituent unit or two or more types. From the viewpoint of fully exhibiting the functions performed by the other structural units in the copolymer, the lower limit of the content of structural units other than structural units (A) and structural unit (B) can be, for example, 1 mol% or more, 5 mol% or more, or 10 mol% or more. Similarly, from the viewpoint of fully exhibiting the functions performed by structural units (A) and structural unit (B) in the copolymer, the upper limit of the content of structural units other than structural units in the copolymer can be preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 30 mol% or less, and even more preferably 20 mol% or less, relative to the total amount of structural units in the copolymer.

[0047] The total amount of constituent units (A) and (B) contained in the copolymer of the present invention is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, even more preferably 70 mol% or more, and particularly preferably 80 mol% or more, based on the total amount of constituent units contained in the copolymer of the present invention, from the viewpoint of the planarization ability of the polishing composition and the solubility of the copolymer. The total amount of constituent units (A) and (B) may also be, for example, 90 mol% or more, 95 mol% or more, 98 mol% or more, etc., based on the total amount of constituent units contained in the copolymer of the present invention. Alternatively, the total amount may be 100 mol% or less. The amounts of constituent units (A) and (B) in the copolymer may be calculated by analyzing the structure of the copolymer by NMR or the like, or by calculating from the amount of each monomer when producing the copolymer.

[0048] The molar ratio (A:B) of constituent unit (A) to constituent unit (B) contained in the copolymer of the present invention is preferably 0.05:99.95 to 30:70, more preferably 0.1:99.9 to 20:80, even more preferably 0.2:99.8 to 15:85, and even more preferably 0.2:99.8 to 11:89, from the viewpoint of the planarization ability of the polishing composition and the solubility of the copolymer.

[0049] The amount of the constituent unit (A) represented by formula (A) in the copolymer of the present invention is preferably 0.01 to 50% by mass, more preferably 0.03 to 40% by mass, even more preferably 0.05 to 30% by mass, even more preferably 0.1 to 20% by mass, and particularly preferably 0.3 to 15% by mass, relative to the total amount of constituent units of the copolymer, from the viewpoint of the planarization ability of the polishing composition and the solubility of the copolymer.

[0050] The proportion of constituent units (A) contained in the copolymer of the present invention is preferably 0.05 mol% or more, more preferably 0.1 mol% or more, and even more preferably 0.2 mol% or more, based on the total amount of constituent units, from the viewpoint of the planarization ability of the polishing composition and the solubility of the copolymer. Furthermore, the proportion of constituent units (A) is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less, and even more preferably 10 mol% or less. The proportion is preferably 0.05 to 30 mol%, more preferably 0.1 to 20 mol%, and even more preferably 0.2 to 10 mol%.

[0051] The proportion of constituent unit (B) (hydrophilic monomer) contained in the copolymer of the present invention is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 80 mol% or more, based on the total amount of constituent units, from the viewpoint of the planarization ability of the polishing composition and the solubility of the copolymer. Furthermore, the proportion of constituent unit (B) is preferably 98 mol% or less, more preferably 95 mol% or less. This proportion is preferably 50 to 98 mol%, more preferably 60 to 98 mol%, and even more preferably 80 to 95 mol%.

[0052] The above-mentioned constituent units (A) and (B), as well as other constituent units that may be included, are derived from monomers having polymerizable groups that can copolymerize with each other. Examples of such monomers include (meth)acrylic monomers or vinyl monomers. Constituent unit (A) is a constituent unit derived from a (meth)acrylic monomer, and constituent unit (B) is preferably a constituent unit derived from a (meth)acrylic monomer or a vinyl monomer, from the viewpoint of ease of copolymerization.

[0053] When constituent units (A) and (B) are derived from (meth)acrylic monomers, constituent units (A) and (B) are, for example, derived from the following formula (Z-1): [In the formula, R ２０ is a hydrogen atom or a methyl group, Z １ -X in equation (A) １ -R ６ -Ph(R １ ) (Caution ２ ) (Caution ３ ) (Caution４ ) (Caution ５ The constituent units may be derived from monomers represented by [representing] or a hydrophilic structure, for example, formulas (1-1) to (1-3), or formulas (2) to (4). １ However, -X in equation (A) １ -R ６ -Ph(R １ ) (Caution ２ ) (Caution ３ ) (Caution ４ ) (Caution ５ When representing ), examples of such monomers include N-(3,4-dihydroxyphenethyl)acrylamide, 2-hydroxy-3-(methacryloyloxy)propyl 3,4-dihydroxybenzoate, hydroxytyrosol methacrylate, and hydroxytyrosol acrylate, with N-(3,4-dihydroxyphenethyl)acrylamide and 2-hydroxy-3-(methacryloyloxy)propyl 3,4-dihydroxybenzoate being preferred. １ However, when representing a hydrophilic structure, examples of such monomers include dimethylacrylamide, N-[3-(dimethylamino)propyl]acrylamide-methyl quaternary chloride, 2-hydroxyethyl (meth)acrylate, and N-(2-carboxyethyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine, with N-(2-carboxyethyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine and N-[3-(dimethylamino)propyl]acrylamide-methyl quaternary chloride being preferred.

[0054] Furthermore, if the constituent unit (B) is derived from a vinyl monomer, (B) can be expressed by, for example, the following formula (Z-2): [In the formula, R ２０ is a hydrogen atom or a methyl group, Z ２ Z may be a constituent unit derived from a monomer represented by a hydrophilic structure, for example, formulas (1-1) to (1-3), or formulas (2) to (4). ２When representing a hydrophilic structure, examples of such monomers include 1-vinyl-2-pyrrolidone, N-vinylacetamide, vinyl alcohol, and sodium 4-vinylbenzenesulfonate, with 1-vinyl-2-pyrrolidone being preferred.

[0055] [Method for producing copolymers] The copolymer of the present invention can be produced by copolymerizing a monomer that gives a structural unit represented by formula (A), which has polymerizable groups that can copolymerize with each other, with a monomer having a hydrophilic structure, and optionally with other monomers.

[0056] When producing copolymers, it is preferable to use at least one polymerization initiator from the viewpoint of promoting the polymerization reaction of monomer components. Examples of polymerization initiators include azo-based lipid-soluble polymerization initiators such as azoisobutyronitrile, methyl azoisobutyrate, and azobisdimethylvaleronitrile; azo-based water-soluble polymerization initiators such as 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]; inorganic peroxides such as benzoyl peroxide, potassium persulfate, and ammonium persulfate; and photopolymerization initiators such as benzophenone derivatives, phosphine oxide derivatives, benzoketone derivatives, phenylthioether derivatives, azide derivatives, diazo derivatives, and disulfide derivatives. However, the present invention is not limited to these examples. These polymerization initiators may be used individually or in combination of two or more types.

[0057] The amount of polymerization initiator is not particularly limited, but is usually preferably about 0.01 to 5 parts by mass per 100 parts by mass of monomer component.

[0058] Polymerization methods for producing the copolymer of the present invention include, for example, bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization, but the present invention is not limited to these examples. Among these polymerization methods, solution polymerization is preferred. When polymerizing monomer components by solution polymerization, for example, the monomer components can be polymerized by dissolving them in a solvent and adding a polymerization initiator while stirring the resulting solution. The polymerization method for producing the copolymer may be photopolymerization or thermal polymerization, but from the viewpoint of manufacturability, thermal polymerization is preferred.

[0059] Examples of solvents include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; aliphatic hydrocarbon compounds such as n-hexane; alicyclic hydrocarbon compounds such as cyclohexane; acetate esters such as methyl acetate and ethyl acetate; and aprotic polar solvents such as dimethylformamide (hereinafter referred to as DMF) and dimethyl sulfoxide (hereinafter referred to as DMSO). However, the present invention is not limited to these examples. These solvents may be used individually or in combination of two or more types.

[0060] The amount of solvent is usually adjusted so that the concentration of the monomer component in the solution obtained by dissolving the monomer component in the solvent is about 10 to 80% by mass.

[0061] When polymerizing monomer components, the polymerization conditions such as polymerization temperature and polymerization time should preferably be adjusted as appropriate according to the type and amount of monomer used as the monomer component, the type and amount of polymerization initiator used, etc.

[0062] The atmosphere used when polymerizing the monomer components is preferably an inert gas. Examples of inert gases include nitrogen gas and argon gas, but the present invention is not limited to these examples.

[0063] The weight-average molecular weight (Mw) of the polymer is preferably 1,000 to 1,000,000, more preferably 1,000 to 800,000, and even more preferably 1,000 to 600,000, from the viewpoint of achieving a high polishing speed while having sufficient planarization ability. In one embodiment of the present invention, the weight-average molecular weight of the polymer may be preferably 10,000 to 200,000, more preferably 20,000 to 180,000, from the viewpoint of planarization and polishing speed. The weight-average molecular weight can be determined by gel permeation chromatography (hereinafter referred to as GPC). The weight-average molecular weight determined by GPC can be determined by the method described in the examples below. From the viewpoint of improving the polishing speed, the weight-average molecular weight (Mw) of the polymer is preferably above the lower limit, and from the viewpoint of the planarization effect, the weight-average molecular weight (Mw) of the polymer is preferably below the upper limit.

[0064] [Abrasive particles] The polishing composition of the present invention contains at least one type of abrasive particle. The abrasive particle is not particularly limited as long as it is a particle that exhibits an abrasive effect, but examples include inorganic oxides, inorganic hydroxides, oxides of inorganic hydroxides, metal borides, metal carbides, metal nitrides, polymer particles, etc. The polishing composition may contain one type of abrasive particle or two or more types of abrasive particles.

[0065] As an inorganic oxide, silica (SiO ２ ), alumina (Al2O ３ ), Zirconia (ZrO ２ ), cerium oxide (cea, CeO ２ ), manganese oxide (MnO ２ ), titanium oxide (TiO ２Examples of abrasives include zinc oxide (ZnO), magnesium oxide (MgO), etc. Examples of inorganic hydroxides include aluminum hydroxide. Examples of oxides of inorganic hydroxides include aluminum hydroxide oxide. Examples of metal borides, metal carbides, and metal nitrides include silicon carbide, silicon nitride, silicon carbonitride, boron carbide, tungsten carbide, zirconium carbide, aluminum boride, tantalum carbide, titanium carbide, etc. These abrasive grains may be, for example, organic polymer coated oxide particles, inorganic coated particles, etc. The abrasive grains are preferably inorganic oxide particles, more preferably at least one selected from the group consisting of silica particles, alumina particles, and ceria particles, and even more preferably at least one selected from the group consisting of silica particles and ceria particles.

[0066] When abrasive grains contain silica, the type of silica is not particularly limited, but colloidal silica is preferred from the viewpoint of wafer surface smoothness. Furthermore, from the viewpoint of suppressing wafer contamination, silica obtained from the hydrolysis of alkoxysilane is preferred, and colloidal silica obtained in the same manner is more preferred.

[0067] The average primary particle size of the abrasive grains is preferably 5 to 100 nm, more preferably 10 to 80 nm, and even more preferably 15 to 60 nm, from the viewpoint of planarization ability and polishing speed. The average primary particle size of the abrasive grains is calculated by the specific surface area S (m²) calculated by the BET (nitrogen adsorption) method. ２ It is calculated using ( / g) and measured according to the method specified in JIS-Z-8830:2013 "Method for determining the specific surface area of ​​powders (solids) by gas adsorption".

[0068] The degree of abrasive particle aggregation is preferably 1.1 to 3.0, more preferably 1.8 to 2.5, from the viewpoint of ensuring a high polishing speed and reducing surface defects (LPDs) of the object to be polished. The degree of abrasive particle aggregation is a coefficient representing the shape of the abrasive particles and is calculated by the following formula. The average secondary particle diameter is the particle diameter measured by dynamic light scattering, which can be measured, for example, using a commercially available dynamic light scattering device. Degree of aggregation = Average secondary particle diameter / Average primary particle diameter

[0069] From the viewpoint of ensuring a high polishing speed, the lower limit of the average secondary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more. From the viewpoint of reducing LPD, the upper limit of the average secondary particle diameter of the abrasive grains is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 150 nm or less. Therefore, the average secondary particle diameter of the abrasive grains measured by dynamic light scattering is preferably 10 to 250 nm, more preferably 20 to 200 nm, and even more preferably 30 to 150 nm.

[0070] From the viewpoint of achieving a high polishing speed while having sufficient planarization ability, the abrasive content is preferably 0.05 to 10% by mass, more preferably 0.1 to 8% by mass, and even more preferably 0.5 to 6% by mass, based on the total weight of the polishing composition.

[0071] [Aqueous Media] The polishing composition of the present invention comprises at least one aqueous media. The polishing composition may contain one aqueous media or two or more aqueous media. Examples of aqueous media include water and mixtures of water and a water-soluble solvent. Examples of water-soluble solvents include alcohols such as methanol, ethanol, and isopropanol. The water is not particularly limited, but from the viewpoint of improving safety during polishing, it is preferable to use water such as deionized water, distilled water, or ultrapure water.

[0072] The amount of aqueous medium contained in the polishing composition of the present invention is preferably 1.0 to 99.9% by mass, more preferably 80 to 98% by mass, and even more preferably 90 to 96% by mass, based on the total weight of the polishing composition, from the viewpoint of achieving a high polishing speed while having sufficient planarization ability, and from the viewpoint of storage stability of the polishing composition.

[0073] [Other Components] The polishing composition of the present invention may optionally contain at least one other component in addition to abrasive grains, a specific polymer, and an aqueous medium, as long as it does not impair the effects of the present invention. Examples of other components include known components that can be included in polishing compositions, such as pH adjusters, polymers other than the specific polymer mentioned above, polishing aids, silicon nitride polishing inhibitors, thickeners, dispersants, rust inhibitors, basic substances, and surfactants. The polishing composition may contain one other component or two or more other components. From the viewpoint of obtaining the effects of adding the component, the amount of these other components is preferably 0.001% by mass or more, more preferably 0.0025% by mass or more, and even more preferably 0.01% by mass or more, based on the total weight of the polishing composition. However, from the viewpoint of polishing speed and planarization ability, the amount is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, based on the total weight of the polishing composition.

[0074] Examples of pH adjusting agents include acidic compounds, alkaline compounds, and salts thereof. Preferably, salts of acidic compounds include at least one selected from alkali metal salts, ammonium salts, and amine salts of acidic compounds, and more preferably, ammonium salts of acidic compounds. Examples of salts of basic compounds include compounds having, as counterions, at least one selected from hydroxide ions, chloride ions, and iodide ions, and more preferably, at least one selected from hydroxide ions and chloride ions.

[0075] Examples of acidic compounds include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid; and organic acids such as acetic acid, oxalic acid, citric acid, and malic acid. Among these, at least one selected from hydrochloric acid, nitric acid, and acetic acid is preferred from the viewpoint of versatility, and at least one selected from hydrochloric acid and acetic acid is more preferred.

[0076] Examples of alkali compounds include inorganic alkali compounds such as ammonia and potassium hydroxide; and organic alkali compounds such as alkylamines and alkanolamines. Among these, at least one selected from ammonia and alkylamines is preferred from the viewpoint of improving the quality of semiconductor substrates, and ammonia is more preferred.

[0077] Examples of abrasives include anionic surfactants and nonionic surfactants. Examples of anionic surfactants include alkyl ether acetates, alkyl ether phosphates, and alkyl ether sulfates. Examples of nonionic surfactants include nonionic polymers such as polyacrylamide and polyoxyalkylene alkyl ethers.

[0078] [Abrasive Composition] The abrasive composition can be produced, for example, by a manufacturing method that includes mixing a dispersion containing abrasive grains and an aqueous medium, a copolymer having constituent unit (A) and constituent unit (B), and other optional components as needed, in a known manner. The order in which these components are mixed is not particularly limited. Mixing can be carried out, for example, using a homomixer, homogenizer, ultrasonic disperser, and wet ball mill.

[0079] The pH of the abrasive composition is preferably 8.0 to 14.0, more preferably 8.5 to 13.5, and even more preferably 9.0 to 13.0, from the viewpoint of achieving both improved polishing speed and storage stability. The pH can be measured using a commercially available pH meter. For example, the pH may be adjusted to the above range by adding a pH adjusting agent to the abrasive composition.

[0080] The solid content of the abrasive composition is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, and even more preferably 4 to 20% by weight, based on the total weight of the abrasive composition, from the viewpoint of improving the polishing speed and storage stability. The solid content can be measured, for example, by the mixing ratio, and is the weight excluding the aqueous medium.

[0081] [Polishing Method] The composition of the present invention can be usefully used as a polishing composition in the polishing process of semiconductor wafer manufacturing. In particular, it can be preferably used as a CMP slurry in the CMP process and may be used as a known polishing composition in semiconductor wafer manufacturing processes.

[0082] The present invention will be described in more detail below with reference to examples, but these examples are not intended to limit the scope of the present invention. In the examples, "%" and "parts" refer to "mass percent" and "parts by mass," respectively, unless otherwise specified.

[0083] The physical properties of the polymer or abrasive composition were measured by the following method.

[0084] (Weight-average molecular weight) The weight-average molecular weight of each polymer was calculated based on the peaks in the chromatogram obtained by performing GPC under the following conditions. Apparatus: HLC-8320 GPC (Tosoh Corporation, integrated detector) Column: Wakobeads-G50 + Wakobeads-G40 (both manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Eluent: Distilled water: Methanol: Acetic acid: Sodium acetate = 936:624:46.8:64 (mass ratio) Flow rate: 0.7 mL / min Column temperature: 30°C Detector: Differential refractive index (RI) Standard substance: Monodisperse polyethylene glycol with known molecular weight

[0085] In the examples and comparative examples, the compounds shown in Table 1 were used. Details of each compound, which is abbreviated in the table and in the following descriptions, are as follows. Dopam: N-(3,4-dihydroxyphenyl)acrylamide (manufactured by Osaka Organic Chemical Industry Co., Ltd.) CM03: 2-hydroxy-3-(methacryloyloxy)propyl 3,4-dihydroxybenzoate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) NVP: 1-vinyl-2-pyrrolidone (manufactured by Tokyo Chemical Industry Co., Ltd.) GLBT: N-(2-carboxyethyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine (manufactured by Osaka Organic Chemical Industry Co., Ltd.) DMAA: N,N-dimethylacrylamide (manufactured by KJ Chemicals Co., Ltd.) DMAPAA-Q: N-[3-(dimethylamino)propyl]acrylamide-methyl chloride quaternary salt (manufactured by KJ Chemicals Co., Ltd.) V-601: 2,2'-azobis(isobutyrate)dimethyl (manufactured by Fujifilm Wako Pure Chemical Corporation) (polymerization initiator) VA-044: 2,2'-Bis(2-imidazolin-2-yl)[2,2'-azobispropane] 2-hydrochloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (polymerization initiator)

[0086] (Example 1-1) 40.0 g of ultrapure water, 40.0 g of ethanol, 19.6 g of NVP, and 0.40 g of Dopam were placed in a 200 mL three-necked flask and heated to 80°C. Then, 0.200 g of V-601 was added and the temperature was maintained. After stirring for 23 hours while maintaining the temperature, the mixture was returned to room temperature to obtain the copolymer according to Example 1-1. The weight-average molecular weight was 43,000.

[0087] (Examples 1-2 to 1-5, 1-8) Polymers according to each example were obtained in the same manner as in Example 1-1, except that the monomer composition was changed as shown in Tables 1 to 3.

[0088] (Examples 1-6) 93.9 g of ultrapure water, 23.5 g of ethanol, 6.8 g of GLBT, and 0.7 g of CM03 were placed in a 200 mL three-necked flask and heated to 80°C. Then 0.168 g of V-601 was added and the temperature was maintained. Ten minutes after adding V-601, a mixture of 6.0 g of ultrapure water, 1.5 g of ethanol, 6.8 g of GLBT, and 0.7 g of CM03 was added dropwise to the reaction flask over 50 minutes and the temperature was maintained. After that, the mixture was stirred for 19 hours while maintaining the temperature, and then returned to room temperature to obtain the copolymer according to Example 1-6. The weight-average molecular weight was 49,000.

[0089] (Examples 1-7) 97.3 g of ultrapure water, 24.3 g of ethanol, 17.6 g of DMAPA-Q, and 0.8 g of CM03 were placed in a 200 mL three-necked flask and heated to 80°C. Then, 0.08 g of V-601 was added and the temperature was maintained. After stirring for 8 hours while maintaining the temperature, the mixture was returned to room temperature to obtain the copolymer according to Example 1-7. The weight-average molecular weight was 24,000.

[0090] (Comparative Example 1-1) 144.0 g of ultrapure water and 16.0 g of NVP were placed in a 200 mL three-necked flask and heated to 90°C. Then 0.256 g of VA-044 was added and the temperature was maintained. After stirring for 16 hours while maintaining the temperature, the mixture was returned to room temperature to obtain the polymer according to Comparative Example 1-1. The weight-average molecular weight was 36,000.

[0091] (Comparative Examples 1-2 to 1-5) Polymers corresponding to each comparative example were obtained in the same manner as in Comparative Example 1-1, except that the compositions were as shown in Tables 2 and 3, the weight-average molecular weight of the contents was sampled at appropriate times, and the stirring time was adjusted.

[0092] (Preparation Example 1: Preparation of Silica Slurry) 30 L of Snowtex (manufactured by Nissan Chemical Corporation) was diluted six times with ultrapure water to obtain a silica slurry with a silica content of 5% by mass. The average primary particle size of the silica was 45 nm.

[0093] (Example 2-1) A polishing composition containing the polymer obtained in Example 1-1 was prepared by diluting the polymer obtained in Example 1-1 with ultrapure water so that the solid content concentration of the polymer was 500 ppm by mass and the silica slurry obtained in Preparation Example 1 had a solid content of 5.0% by mass. Specifically, the proportions of each component in 100 g of the polishing composition were polymer: 0.05%, silica: 5%, and water: 94.95%.

[0094] (Examples 2-2 to 2-8, Comparative Examples 2-1 to 2-5) Polishing compositions were prepared in the same manner as in Example 2-1, except that the polymers shown in Tables 1 to 3 were used instead of the polymer obtained in Example 1-1.

[0095] (Polishing Process) The polishing compositions prepared according to the methods described in the above examples and comparative examples were used as CMP slurries, and polishing was performed using a polishing apparatus under the following conditions. The polishing speed was calculated according to the method described below. Polishing was performed six times under the same conditions, and the average value of the obtained polishing speeds was taken as the polishing speed. The same method was used for the Ra value. Polishing apparatus: SPL-15F (single-sided polishing machine) manufactured by Okamoto Machine Tool Works, Ltd. Polishing pad: SUBA-800 manufactured by Nitta DuPont Ltd. Object to be polished: Silicon wafer Plate rotation speed: 60 rpm Head rotation speed: 60 rpm Polishing load: 10.6 kPa Polishing liquid supply rate: 20 mL / min Polishing time: 10 minutes

[0096] The polishing speed and flattening effect in the polishing process were evaluated according to the following method. The results are shown in Tables 1 to 3.

[0097] (Planarization Effect) Using a white-light interference microscope (Zygo NewView 7300), 17 measurements were taken on the surface (polished surface) of the polished object after polishing, and the surface roughness of the polished object after polishing was calculated by determining the average Ra value. The planarization effect can also be evaluated from the ratio of Ra values ​​in each example and comparative example, for example, when the Ra value of the composition containing the homopolymer of the main monomer of the copolymer is set to 1. A smaller Ra value means a higher surface planarization effect, and a smaller ratio of Ra values ​​indicates that the planarization effect has improved due to the use of the resin.

[0098] (Polishing Speed) The weight of the object to be polished before and after polishing was measured using a precision balance, and the single-sided polishing speed per unit time was determined by dividing the obtained weight difference by the density, area, and polishing time of the silicon substrate. Note that the weight of the object to be polished after polishing is the weight after washing with ultrapure water and drying. The polishing speed can also be evaluated from the ratio of the polishing speed in each example and comparative example, when the polishing speed of the composition containing the homopolymer of the main monomer of the copolymer is set to 1. A larger ratio of polishing speed indicates that the polishing speed has increased due to the use of resin. Polishing speed (μm / min) = {(Weight of object before polishing [g] - Weight of object after polishing [g]) × 10000} / (Density of object to be polished [g / cm³]) ３ ] × Area of ​​the surface to be polished [cm² ２ ] × Polishing time [minutes])

[0099]

[0100]

[0101]

[0102] As shown in Tables 1 to 3, it was confirmed that the polishing composition of the present invention, which comprises a specific copolymer, abrasive grains, and an aqueous medium, exhibits a lower Ra value and improved planarization ability compared to a composition containing a homopolymer of the main monomer of the copolymer.

Claims

1. Formula (A): [In formula (A), X １ represents -N(-H)- or -O-, and R １ ~R ５ Each of these independently represents a hydrogen atom or -OH, except R １ ~R ５ At least two adjacent ones among them represent -OH, R ６ represents a linear or branched alkylene or alkenylene group having 1 to 7 carbon atoms, which may have substituents, and contains one or more -CH groups. ２ The - may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-, R ７ An abrasive composition comprising a copolymer having at least one constituent unit (A) represented by [wherein a hydrogen atom or methyl group] and one constituent unit (B) having a hydrophilic structure, abrasive grains, and an aqueous medium.

2. The polishing composition according to claim 1, wherein the weight-average molecular weight of the copolymer is 1,000 to 1,000,000.

3. The polishing composition according to claim 1 or 2, wherein the hydrophilic structure is at least one structure selected from the group consisting of a cationic structure, anionic structure, betaine structure, amide structure, alkylene oxide structure, hydroxyl group-containing structure, lactam structure, and amine structure.

4. The polishing composition according to claim 1 or 2, wherein the hydrophilic structure comprises a betaine structure having at least one atom selected from the group consisting of a positively charged quaternary nitrogen atom, a positively charged tertiary sulfur atom, and a positively charged quaternary phosphorus atom.

5. The betaine structure is represented by the formula (1-1): [wherein, R ８ represents a linear or branched alkylene group having 1 to 6 carbon atoms, R ９ and R １０ each independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, R １１ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -O － , -SO ３ － or -COO － represents, and * represents a bond], the polishing composition according to claim 4.

6. The polishing composition according to claim 1 or 2, wherein the amount of constituent unit (A) represented by formula (A) in the copolymer is 0.01 to 50% by mass relative to the total amount of constituent units in the copolymer.

7. The polishing composition according to claim 1 or 2, wherein the amount of copolymer contained in the polishing composition is 0.0001 to 6% by mass based on the total weight of the polishing composition.

8. The polishing composition according to claim 1 or 2, wherein the abrasive particles are silica particles and / or ceria particles.

9. Formula (A): [In formula (A), X １ represents -N(-H)- or -O-, and R １ ~R ５ Each of these independently represents a hydrogen atom or -OH, except R １ ~R ５ At least two adjacent ones among them represent -OH, R ６ represents a linear or branched alkylene or alkenylene group having 1 to 7 carbon atoms, which may have substituents, and contains one or more -CH groups. ２ The - may be substituted with -O-, -C(=O)-O-, -O-C(=O)-, -CH(-OH)-, or -C(=O)-, R ７ A copolymer having at least one constituent unit (A) represented by [wherein it represents a hydrogen atom or a methyl group] and one constituent unit (B) having a hydrophilic structure.

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