Method for producing an abrasive composition containing a modified polyvinyl alcohol composition and an abrasive composition containing a modified polyvinyl alcohol composition

Abstract

To provide a method for producing a polishing composition that has excellent filterability and enables reduction of the surface defects in a polishing object.SOLUTION: The present invention provides a method for producing a polishing composition comprising a modified polyvinyl alcohol composition, which comprises a modified polyvinyl alcohol or a derivative thereof, and water. The method includes a heat insulation step of holding the modified polyvinyl alcohol composition at a solution temperature of 30°C or higher and lower than 60°C. The heat insulation step is performed so that the parameter A becomes 2.0 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a polishing composition containing a modified polyvinyl alcohol composition and a polishing composition containing a modified polyvinyl alcohol composition.

Background Art

[0002] Modified polyvinyl alcohol is a polyvinyl alcohol having a substituent (functional group) other than a hydroxyl group, and various properties can be imparted based on the substituent. Since modified polyvinyl alcohol is a hydrophilic synthetic resin, it is often dispersed in water and used in the form of a fluid solution (aqueous solution) as a fiber raw material, sizing agent, paint, adhesive, emulsifier, etc.

[0003] For example, Patent Document 1 discloses that a polishing liquid composition for a silicon wafer containing modified polyvinyl alcohol can achieve both reduction of the surface roughness (haze) and reduction of surface defects (LPD) of the silicon wafer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, a solution containing modified polyvinyl alcohol has a problem of poor filterability. For example, when polishing an object to be polished with a polishing composition containing foreign matter, there is a concern that excessive pressure is locally applied to the object to be polished, resulting in damage to the object to be polished. Therefore, when producing a polishing composition, filtration is often performed on those in the form of a solution. Thus, components added to the polishing composition in the form of a solution (Solution containing modified polyvinyl alcohol)Filtration performance is crucial. Poor filtration performance leads to longer filtration times, lower yields, and significantly reduced productivity. Furthermore, the technology described in Patent Document 1 was not yet sufficient in terms of reducing surface defects (LPDs).

[0006] Therefore, the present invention is In light of the importance of the filterability of the component (solution containing modified polyvinyl alcohol) added to the polishing composition in solution form, the filterability of the solution containing modified polyvinyl alcohol Filtration of Good The process involves making it look like The objective is to provide a method for manufacturing a polishing composition that can reduce surface defects in an object to be polished. [Means for solving the problem]

[0007] In order to solve the above-mentioned new problems, the inventors have diligently conducted research. As a result, a method for producing a polishing composition comprising a modified polyvinyl alcohol composition containing modified polyvinyl alcohol or a derivative thereof and water, comprising a heat retention step of maintaining the modified polyvinyl alcohol composition at a solution temperature of 30°C or higher and less than 60°C, wherein the heat retention step is performed by parameter A, which is represented by the following formula:

[0008]

number

[0009] We discovered that the above problems can be solved by a method for manufacturing an abrasive composition in which the ratio is 2.0 or higher, and thus completed the present invention. [Effects of the Invention]

[0010] The present invention provides a method for producing an abrasive composition that has good filterability and can reduce surface defects in an object to be polished. [Modes for carrying out the invention]

[0011] The present invention relates to a method for producing a polishing composition comprising a modified polyvinyl alcohol composition containing modified polyvinyl alcohol or a derivative thereof and water, comprising a heat retention step of maintaining the modified polyvinyl alcohol composition at a solution temperature of 30°C or higher and less than 60°C, wherein the heat retention step comprises parameter A represented by the following formula:

[0012]

number

[0013] This is a method for manufacturing an abrasive composition, in which the process is carried out so that the ratio is 2.0 or higher. The abrasive composition obtained through such a heat retention process has excellent filterability and can reduce surface defects in the object to be polished. Furthermore, according to one embodiment, the abrasive composition containing the modified polyvinyl alcohol composition obtained by such a manufacturing method has excellent storage stability.

[0014] The mechanism by which these effects are obtained is thought to be as follows. However, the mechanism described below is merely speculative and does not limit the scope of the present invention.

[0015] Modified polyvinyl alcohol or its derivatives (hereinafter also simply referred to as "modified PVA") swells when dispersed in water, forming hydrogen bonds within and / or between the modified PVA molecules. As a result, it is thought that aggregates (also referred to as "particles") are formed in water from several modified PVA molecules. At this time, it is thought that aggregates of various sizes are formed depending on the degree of swelling of the modified PVA, and that coarse aggregates also exist. In the manufacturing method of the present invention, it is speculated that the heat retention step, performed so that the above parameter A is 2.0 or higher, can break the hydrogen bonds formed between molecules in the coarse aggregates present in the modified polyvinyl alcohol composition containing modified PVA and water (hereinafter also simply referred to as "modified PVA composition"), thereby making the aggregates smaller.

[0016] In this specification, the heat retention step may be carried out by any of the following: leaving the modified PVA composition undisturbed in a space maintained at a constant temperature; stirring the modified PVA composition in a space maintained at a constant temperature; or adding the modified PVA composition to a temperature-controllable container and leaving it undisturbed or stirring it.

[0017] Embodiments of the present invention will be described below. However, the present invention is not limited to the embodiments described below. In this specification, "X~Y" indicating a range means "X or more and Y or less", and "weight" and "mass", "weight%" and "mass%", and "parts by weight" and "parts by mass" are treated as synonyms. In addition, unless otherwise specified in this specification, operations and measurements of physical properties, etc. are performed under conditions of room temperature (20°C or more and 25°C or less) / relative humidity 40%RH or more and 50%RH or less.

[0018] [Method for producing abrasive compositions] The present invention relates to a method for producing an abrasive composition comprising a modified PVA composition containing modified PVA (modified polyvinyl alcohol or a derivative thereof) and water, comprising a heat retention step of maintaining the modified PVA composition at a solution temperature of 30°C or higher and less than 60°C, wherein the heat retention step comprises parameter A represented by the following formula:

[0019]

number

[0020] The process is carried out so that the ratio is 2.0 or higher. In other words, the method for producing the polishing composition of the present invention includes a preparation step of preparing a modified PVA composition. It can also be said that the method for producing the polishing composition of the present invention includes a step of preparing a polishing composition using a modified PVA composition obtained through a predetermined heat retention step.

[0021] Modified PVA Here, we will describe the modified PVA used in the manufacturing method of the present invention.

[0022] As used herein, modified PVA means modified polyvinyl alcohol or a derivative of modified polyvinyl alcohol. Modified polyvinyl alcohol refers to a polymer containing, as repeating units, vinyl alcohol units (hereinafter also referred to as "VA units") in addition to repeating units other than VA units (hereinafter also referred to as "non-VA units"). A derivative of modified polyvinyl alcohol is a compound having modified polyvinyl alcohol in the molecule. Hereinafter, unmodified polyvinyl alcohol is referred to as non-modified PVA with respect to the modified polyvinyl alcohol or its derivative used in the present invention.

[0023] Non-modified PVA contains, as a repeating unit, a structural part represented by the chemical formula: -CH2-CH(OH)-, that is, a VA unit. Non-modified PVA is produced by hydrolyzing (saponifying) polyvinyl acetate. Non-modified PVA refers to PVA substantially free of repeating units of a structure in which vinyl acetate is polymerized (-CH2-CH(OCOCH3)-) and repeating units other than VA units.

[0024] In the present invention, the modified PVA may have, as a non-VA unit, a structural part represented by the chemical formula: -CH2-CH(X)- or the chemical formula: -CH(X)-CH(X)- (hereinafter also referred to as "modified VA unit"). Here, X may be a group other than a hydroxyl group (-OH). X is, for example, an alkyl ether group (-O-R 1 ; R 1 is an alkyl group having 1 to 10 carbon atoms), an alkyl carbonyl ether group (-O-C(=O)-R 1 ; R 1 is an alkyl group having 1 to 10 carbon atoms), a sulfonic acid group (-S(=O)2-OH), a carboxylic acid group (-C(=O)-OH), a carboxylic acid ester group (-C(=O)OR; R 1 is an alkyl group having 1 to 10 carbon atoms), a polyalkyleneoxy ether group (-O-(R 2 O) n -H; R 2 is an alkylene group having 2 to 5 carbon atoms, and n is the number of moles of alkylene oxide added), an amino ether group (-O-NR 3 ; R 3Each is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 20 carbon atoms, or an alkylcarbonylalkylene group (-R 4 -OR 1 ;R 1 R is an alkyl group having 1 to 10 carbon atoms. 4 (A C1-C10 alkylene group), alkylcarbonylalkylene group (-R 4 -C(=O)-R 1 ;R 1 R is an alkyl group having 1 to 10 carbon atoms. 4 (Among these are alkylene groups with 1 to 10 carbon atoms), amino groups (-NR) 3 ;R 3 Preferably, each of these is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0025] Of these, X is preferably an alkyl ether group, and more preferably a methyl ether group (-O-CH3), ethyl ether group, propyl ether group, butyl ether group, etc. Using such modified PVA provides suitable protection for the substrate, thereby further enhancing the effects of the present invention. Here, the alkyl group may be linear, branched, or alicyclic, and is preferably a linear alkyl group.

[0026] Examples of non-VA units that may be included in modified PVA include, but are not limited to, repeating units derived from N-vinyl type monomers or N-(meth)acryloyl type monomers, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, and repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, as described later. One preferred example of the above N-vinyl type monomer is N-vinylpyrrolidone. One preferred example of the above N-(meth)acryloyl type monomer is N-(meth)acrylomorpholine. The above alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group with 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The above vinyl ester of monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate.

[0027] The modified PVA may be a modified PVA in which some of the VA units are acetalized with an aldehyde. As the aldehyde, for example, alkyl aldehydes can be preferably used, and alkyl aldehydes having an alkyl group with 1 to 7 carbon atoms are preferred, with acetaldehyde, n-propyl aldehyde, n-butyraldehyde, and n-pentyl aldehyde being particularly preferred. Using such a modified PVA provides suitable protection for the substrate, thereby further enhancing the effects of the present invention.

[0028] As the modified PVA, a cation-modified polyvinyl alcohol in which a cationic group such as a quaternary ammonium structure has been introduced may be used. Examples of the above-mentioned cation-modified polyvinyl alcohol include those into which a cationic group derived from a monomer having a cationic group, such as diallyldialkylammonium salt or N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt has been introduced. As the modified PVA, the non-VA unit has the chemical formula: -CH2-CH(CR 5 (OR 8 )-CR 6(OR 9 )-R 7 It may have a structural part represented by )-. Here R 5 ~R 7 Each of these independently represents a hydrogen atom or an organic group, R 8 and R 9 Each is independently a hydrogen atom or R 10 -CO-(wherein, R 10 ) indicates an alkyl group. ) Examples of such modified PVA include modified PVA having a 1,2-diol structure in its side chain.

[0029] The modified PVA may also be a modified PVA comprising VA units and non-VA units having at least one structure selected from an oxyalkylene group, a carboxyl group, a (di)carboxylic acid group, a (di)carboxylic acid ester, a phenyl group, a naphthyl group, a sulfo group, an amino group, a hydroxyl group, an amide group, an imide group, a nitrile group, an ether group, an ester group, and salts thereof.

[0030] Modified PVA may be a random copolymer, block copolymer, alternating copolymer, or graft copolymer containing non-VA units and VA units. Modified PVA may contain only one type of non-VA unit, or it may contain two or more types of non-VA units.

[0031] The upper limit of the degree of saponification of modified PVA is not particularly limited, but can be 100 mol% or less, 98 mol% or less, 95 mol% or less, 90 mol% or less, or 85 mol% or less. The lower limit of the degree of saponification of modified PVA is preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, and particularly preferably 85 mol% or more. The degree of saponification of modified PVA can be determined by titrating the residual acetate groups with alkali, as well as by near-infrared spectroscopy (IR) or nuclear magnetic resonance (NMR). The effects of the present invention are further enhanced when the degree of saponification of modified PVA is within the above range. In this specification, the degree of saponification is a value obtained by measurement in accordance with JIS-K6726 (1994).

[0032] In one embodiment, the modified PVA has a structural portion represented by the following general formula (1) as a non-VA unit. In this case, the degree of saponification is 85-88 mol%, and the degree of acetal is 25-40 mol%.

[0033] [ka]

[0034] (In formula (1), R is a hydrogen atom, an alkyl group, an alkylene group, or an oxyalkylene group, wherein the alkyl group is a linear or branched alkyl group, and the alkyl group or alkylene group may be substituted with a functional group.) In one embodiment, the modified PVA has a structural moiety represented by the chemical formula -CH2-CH(-OR)-(R is a butyl group) as a non-VA unit. In this case, the degree of saponification is 97-99 mol%, and the butyl ether group is 5-15 mol%.

[0035] The ratio of moles of non-VA units to the total number of moles of repeating units constituting the modified PVA may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. Although not particularly limited, in some embodiments, the ratio of moles of non-VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (for example, 95% or more, or 98% or more). Furthermore, the ratio of moles of non-VA units to the total number of moles of repeating units constituting the modified PVA may be, for example, 99% or less, 98% or less, 95% or less, 90% or less, or 80% or less.

[0036] The content of non-VA units in modified PVA (by mass) may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more. Although not particularly limited, in some embodiments, the content of modified VA units may be 50% by mass or more (for example, more than 50% by mass), 70% by mass or more, or 80% by mass or more (for example, 90% by mass or more, or 95% by mass or more, or 98% by mass or more). Furthermore, the content of non-VA units in modified PVA (by mass) may be, for example, 99% by mass or less, 98% by mass or less, 95% by mass or less, 90% by mass or less, or 80% by mass or less.

[0037] Modified PVA may contain multiple polymer chains with different non-VA unit content within the same molecule. Here, a polymer chain refers to a part (segment) that constitutes a portion of a polymer molecule. For example, modified PVA may contain polymer chain A, which has a non-VA unit content of more than 50% by mass, and polymer chain B, which has a non-VA unit content of less than 50% by mass (i.e., a VA unit content of more than 50% by mass), within the same molecule.

[0038] Polymer chain A may contain only non-VA units as repeating units, or it may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain A may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the content of non-VA units in polymer chain A may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting polymer chain A may be non-VA units.

[0039] Polymer chain B may contain only VA units as repeating units, or it may contain non-VA units in addition to VA units. The VA unit content in polymer chain B may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the VA unit content in polymer chain B may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting polymer chain B may be VA units.

[0040] Examples of modified PVA containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The above graft copolymer may be a graft copolymer in which polymer chain B (side chain) is grafted onto polymer chain A (main chain), or a graft copolymer in which polymer chain A (side chain) is grafted onto polymer chain B (main chain). In one embodiment, a modified PVA in which polymer chain B is grafted onto polymer chain A can be used.

[0041] Examples of polymer chain A include polymer chains whose main repeating units are derived from N-vinyl monomers, polymer chains whose main repeating units are derived from N-(meth)acryloyl monomers, polymer chains whose main repeating units are derived from vinyl dicarboxylates such as fumaric acid, maleic acid, and maleic anhydride, polymer chains whose main repeating units are derived from aromatic vinyl monomers such as styrene and naphthalene vinyl, and polymer chains whose main repeating units are oxyalkylene units. In this specification, unless otherwise specified, the main repeating unit refers to a repeating unit present in an amount exceeding 50% by mass.

[0042] One preferred example of polymer chain A is a polymer chain whose main repeating unit is an N-vinyl type monomer, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl type monomers in the N-vinyl polymer chain is typically more than 50% by mass, may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. It is also possible that substantially all of polymer chain A consists of repeating units derived from N-vinyl type monomers.

[0043] In this specification, examples of N-vinyl type monomers include monomers having a nitrogen-containing heterocyclic ring (e.g., a lactam ring) and N-vinyl chain amides. Specific examples of N-vinyl lactam type monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholindione. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. Polymer chain A may be an N-vinyl polymer chain in which more than 50% by mass (e.g., 70% or more by mass, or 85% or more by mass, or 95% or more by mass) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinylpyrrolidone units.

[0044] Another example of polymer chain A is a polymer chain whose main repeating unit is an N-(meth)acryloyl type monomer, i.e., an N-(meth)acryloyl polymer chain. The content of repeating units derived from N-(meth)acryloyl type monomers in an N-(meth)acryloyl polymer chain is typically more than 50% by mass, may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. It is also possible that substantially all of polymer chain A consists of repeating units derived from N-(meth)acryloyl type monomers.

[0045] In this specification, examples of N-(meth)acryloyl type monomers include chain amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamides; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0046] Another example of polymer chain A is a polymer chain containing oxyalkylene units as the main repeating units, i.e., an oxyalkylene polymer chain. The oxyalkylene unit content in the oxyalkylene polymer chain is typically more than 50% by mass, may be 70% or more by mass, 85% or more by mass, or 95% or more by mass. Substantially all of the repeating units contained in polymer chain A may be oxyalkylene units.

[0047] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be repeating units derived from the corresponding alkylene oxide. The oxyalkylene polymer chain may contain one type of oxyalkylene unit or two or more types. For example, it may be an oxyalkylene polymer chain containing a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, these oxyalkylene units may be random copolymers of the corresponding alkylene oxides, block copolymers, alternating copolymers, or graft copolymers.

[0048] Other examples of polymer chain A include polymer chains that primarily contain alkyl vinyl ether units, structural units obtained by acetalizing polyvinyl alcohol and aldehydes, etc. Among these, it is preferable to select from the group consisting of vinyl ether units having an alkyl group with 1 to 10 carbon atoms (alkyl vinyl ether units), vinyl ester units derived from monocarboxylic acids having 1 to 7 carbon atoms (monocarboxylic acid vinyl ester units), and structural units obtained by acetalizing polyvinyl alcohol and aldehydes having an alkyl group with 1 to 7 carbon atoms.

[0049] Examples of vinyl ether units having an alkyl group with 1 to 10 carbon atoms include propyl vinyl ether units, butyl vinyl ether units, and 2-ethylhexyl vinyl ether units. Examples of vinyl ester units derived from monocarboxylic acids with 1 to 7 carbon atoms include vinyl propanoate units, vinyl butanoate units, vinyl pentanoate units, and vinyl hexanoate units.

[0050] The weight-average molecular weight (Mw) of modified PVA is not particularly limited. The Mw of modified PVA is typically 2 × 10⁻⁶. 3 That's all. 5 × 10 3It may be greater than or equal to 1 × 10 4 The above is also acceptable. As the Mw of the modified PVA increases, the polishing speed tends to increase.

[0051] The weight-average molecular weight (Mw) of modified PVA is typically 100 × 10⁻⁶. 4 The following is appropriate: 30 × 10 4 The following is preferable: 20 × 10 4 (for example, 15 x 10) 4 The following may also be used. From the viewpoint of balancing polishing rate and substrate surface protection, the Mw of the modified PVA should be 10 × 10 4 The following is also acceptable: 8 × 10 4 The following is also acceptable.

[0052] In this specification, weight-average molecular weight (Mw) refers to a value based on aqueous gel permeation chromatography (GPC) (aqueous system, polyethylene oxide equivalent). The GPC measuring instrument used is the "HLC-8320GPC" model manufactured by Tosoh Corporation. Measurement conditions are, for example, as follows:

[0053] [GPC measurement conditions] Sample concentration: 0.1% by mass Column: TSKgel GMPWXL Detector: Differential refractometer Eluent: 100 mM sodium nitrate aqueous solution Flow rate: 1mL / min Measurement temperature: 40℃ Sample injection volume: 200 μL.

[0054] The degree of polymerization of the modified PVA is preferably 50 or higher, more preferably 100 or higher. The degree of polymerization of the modified PVA can be, for example, 120 or higher, 150 or higher, or 200 or higher. Alternatively, the degree of polymerization of the modified PVA can be, for example, 4000 or lower. If the degree of polymerization of the modified PVA is within the above range, the effects of the present invention will be fully realized.

[0055] Examples of modified PVA used in this invention include "Elvanol" manufactured by Kuraray Co., Ltd. and "Gosenex" manufactured by Mitsubishi Chemical Corporation.

[0056] • Method for manufacturing abrasive compositions The method for producing the polishing composition of the present invention is not particularly limited except that it is prepared using a modified PVA composition obtained through the predetermined heat retention step described in (1b) below. However, it is preferable to include one or more of the following steps (1a), (2), and (3) in addition to the predetermined heat retention step described in (1b) below. The modified PVA composition obtained through step (1) may be used as is as the polishing composition.

[0057] "Method for manufacturing abrasive compositions" (1) Preparation process for preparing a modified PVA composition (1a) Dissolution process of modified PVA (1b) Heat retention process of modified PVA composition (2) Preparation step of preparing an abrasive composition by adding other components to the modified PVA composition. (3) Filtration step of filtering the abrasive composition The following explains steps (1) to (3) above in order.

[0058] In one embodiment, the method for producing the polishing composition of the present invention further includes a preparation step of adding abrasive particles and a pH adjuster to a modified PVA composition after a heat retention step to prepare a polishing composition, and a filtration step of filtering the polishing composition obtained in the preparation step. That is, it is preferable to include steps (2) and (3) above.

[0059] (1) Preparation process for preparing a modified PVA composition The preparation step for preparing the modified PVA composition may include a predetermined heat retention step, but may also include a step for dissolving the modified PVA in addition to the heat retention step. The predetermined heat retention step is a step in which the modified PVA composition is heated to a temperature represented by the following formula, parameter A:

[0060]

number

[0061] The solution temperature should be maintained between 30°C and 60°C so that the ratio is 2.0 or higher.

[0062] (1a) Dissolution process of modified PVA The dissolution step of modified PVA is a step of mixing modified PVA with water to obtain a modified PVA composition.

[0063] In the present invention, modified PVA may be synthesized by known methods or obtained as a commercially available product. Commercially available products may be modified PVA in a solid state (e.g., powder) or modified PVA in a solution state dissolved in a solvent (water) (modified PVA composition). If the commercially available modified PVA is in a solid state, the dissolution step involves mixing the modified PVA with water to dissolve the modified PVA in water and obtain a modified PVA composition. If the commercially available modified PVA is in a solution state, the dissolution step is not required, and it may be used as is as a modified PVA composition. Alternatively, if the commercially available modified PVA is in a solution state, the modified PVA in solution state may be mixed with water (modified PVA dissolved in water), and the diluted commercially available modified PVA in solution state may be used as a modified PVA composition.

[0064] The water used in the dissolution process serves as the solvent for the modified PVA in the modified PVA composition. It is preferable that the water contains as few impurities as possible. Preferably, this water is water from which impurity ions have been removed by ion exchange resin, filtration, or distillation. Examples of such water include ion-exchanged water, pure water, ultrapure water, and distilled water. To minimize interference with the function of other components in the polishing composition, it is preferable that the total content of transition metal ions is 100 ppb or less.

[0065] The temperature of the water used when mixing modified PVA with water (dissolving modified PVA in water) is preferably 15°C or higher, and more preferably 20°C or higher. Alternatively, the temperature of the water used when mixing modified PVA with water (dissolving modified PVA in water) can be, for example, less than 60°C. When the water temperature is within the above range, the dissolution rate of modified PVA can be increased.

[0066] The content of modified PVA in the modified PVA composition is the same as the content of modified PVA in the heat retention process described later. It is preferable that the content of modified PVA in the modified PVA composition is within the above range because the modified PVA composition can be prepared efficiently.

[0067] The water content in the modified PVA composition is the same as the water content in the heat retention process described later. It is preferable that the water content in the modified PVA composition is within the above range because it allows for efficient preparation of the modified PVA composition.

[0068] The modified PVA composition may contain other additives, but considering the impact of the additives on stability in the subsequent heat retention step, the modified PVA composition before and during the heat retention step is preferably composed of modified PVA and water. However, the modified PVA composition may contain a pH adjuster for pH adjustment. The pH of the modified PVA composition before and during the heat retention step is preferably 2 to 11, more preferably 3 to 10, and even more preferably 3 to 9.

[0069] When dissolving modified PVA in water, stirring is preferable. For example, the dissolution process is preferably carried out in a stirring container equipped with a stirrer.

[0070] The dissolution process is preferably terminated when the modified PVA is uniformly dissolved, and the process proceeds to the next heating process.

[0071] (1b) Heat retention process of modified PVA composition In the polishing composition of the present invention, the method for producing the modified PVA composition includes a heat retention step for the modified PVA composition. In the present invention, the heat retention step is a step of maintaining the modified PVA composition, which has become below 30°C after the dissolution step, at a solution temperature of 30°C or higher and less than 60°C. The solution temperature of the modified PVA composition in the heat retention step is preferably 32°C or higher, more preferably 33°C or higher, and even more preferably 34°C or higher. The solution temperature of the modified PVA composition in the heat retention step is preferably 55°C or lower, more preferably 50°C or lower, and even more preferably 45°C or lower. From the viewpoint of avoiding structural changes of the modified PVA, it is preferable that the solution temperature of the modified PVA composition in the heat retention step is below the cloud point of the modified PVA.

[0072] Furthermore, the end of the heat retention process is determined when the solution temperature of the modified PVA composition falls outside the temperature range defined for the heat retention process. The modified PVA composition before the start of the heat retention process and after the end of the heat retention process is not particularly limited, but it is preferable to leave it standing at 15°C or higher and less than 30°C.

[0073] In the present invention, the heat retention process is carried out such that the following parameter A is 2 or greater.

[0074]

number

[0075] If the heat retention process is carried out so that the above parameter A is less than 2, the hydrogen bonds formed between the modified PVA molecules will not be broken, and therefore, modified PVA particles with a large particle size will remain even after the heat retention process, and the filterability of the modified PVA composition will not be improved. The lower limit of parameter A in the heat retention process is preferably 2.1 or higher, and more preferably greater than 2.1. The upper limit of parameter A in the heat retention process is not particularly limited, but is preferably 5000 or lower, more preferably 4000 or lower, even more preferably 3000 or lower, and particularly preferably 2500 or lower. If the process is carried out with parameter A exceeding 5000 at a high solution temperature of the modified PVA composition, there is a risk that the modified PVA in the modified PVA composition will decompose due to heat.

[0076] The duration of the heat retention process is set appropriately so that parameter A is 2 or more, but is preferably 0.25 hours or more, and more preferably 0.5 hours or more. The duration may be, for example, 1 hour or more, 1.5 hours or more, 3 hours or more, or 5 hours or more. The duration of the heat retention process is set appropriately so that parameter A is 2 or more, but is preferably 300 hours or less, and more preferably 250 hours or less. The duration may be, for example, 200 hours or less, 150 hours or less, 100 hours or less, 50 hours, or 24 hours or less. According to one embodiment, the heat retention process is performed for 0.5 hours or more and 200 hours or less.

[0077] The concentration (content) of modified PVA in the modified PVA composition when the heat retention process is carried out is appropriately set so that the above parameter A is 2 or more. For example, the concentration (content) of modified PVA in the modified PVA composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, based on the total mass of the composition. Furthermore, the concentration (content) of modified PVA in the modified PVA composition is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, based on the total mass of the composition. According to one embodiment, modified polyvinyl alcohol or its derivative is contained in an amount of 0.1% by mass or more and 40% by mass or less based on the total mass of the modified polyvinyl alcohol composition.

[0078] The temperature retention process can be carried out in any form, but for example, the modified PVA composition may be placed in a container and left to stand in a warehouse or the like where the temperature is maintained at 30°C or higher but less than 60°C. Alternatively, the modified PVA composition may be placed in a temperature-controlled jacketed container and the solution temperature may be adjusted to the temperature of the temperature retention process while stirring the modified PVA composition inside the container.

[0079] The polishing composition according to the present invention, which includes a modified PVA composition obtained through a heat retention process carried out so that parameter A is 2 or greater, has good filterability and can reduce surface defects in the object to be polished.

[0080] In addition to the above findings, the inventors have discovered that the radius of inertia (Rg1) of the modified PVA particles formed in the modified PVA composition fluctuates before and after the heat retention process. Before the heat retention process, the radius of inertia (Rg0) of the modified PVA particles in the modified PVA composition was 65 nm, for example, in the case of alkyl-modified PVA. On the other hand, after the heat retention process, the radius of inertia (Rg1) of the modified PVA particles in the modified PVA composition was less than 65 nm. That is, the radius of inertia (Rg1) of the modified PVA particles after the heat retention process is less than the radius of inertia (Rg0) of the modified PVA particles before the heat retention process. This suggests that the heat retention process breaks the hydrogen bonds formed between molecules in the modified PVA particles (aggregates), resulting in a reduction in the size of the modified PVA particles (aggregates).

[0081] The radius of inertia (Rg1) of modified PVA particles in a modified PVA composition varies depending on the type of modified PVA, molecular weight, concentration, etc., and therefore cannot be stated definitively. However, for example, the radius of inertia (Rg1) of modified PVA particles in a modified PVA composition after the heat retention process is preferably less than 65 nm, more preferably 60 nm or less, even more preferably 55 nm, particularly preferably 50 nm or less, and most preferably 45 nm or less. The lower limit of the radius of inertia (Rg1) of modified PVA particles in a modified PVA composition is not particularly limited, but for example, it is preferably 2 nm or more, more preferably 5 nm or more, even more preferably 7 nm or more, particularly preferably 8 nm or more, and most preferably 10 nm or more. In other words, the radius of inertia (Rg1) of the modified PVA particles in the modified PVA composition after the heat retention process is preferably 2 nm or more and less than 65 nm, more preferably 5 nm or more and 60 nm or less, even more preferably 7 nm or more and 55 nm or less, particularly preferably 7 nm or more and 50 nm or less, and most preferably 8 nm or more and 40 nm or less.

[0082] The radius of inertia (Rg0) of modified PVA particles in the modified PVA composition before the heat retention process varies depending on the type, molecular weight, and concentration of the modified PVA, and therefore cannot be generalized. However, it is larger than the radius of inertia (Rg1) of modified PVA particles in the modified PVA composition after the heat retention process. Therefore, whether or not the heat retention process has been performed on a modified PVA composition can also be determined by the rate of change of Rg1 from Rg0 (Rg1 / Rg0). In the modified PVA composition after the heat retention process, the rate of change is preferably 95% or less, and more preferably 90% or less. The rate of change may also be, for example, 88% or less, 85% or less, 80% or less, 70% or less, 60% or less, or 50% or less. According to one embodiment, in a modified PVA composition, the rate of change (Rg1 / Rg0) of the radius of inertia of the modified PVA after the heat retention process (Rg1 / Rg0) relative to the radius of inertia of the modified PVA before the heat retention process (Rg0) is 95% or less.

[0083] The radius of inertia of modified PVA particles in a modified PVA composition that has undergone a heat retention process shows little change over time. For example, it has been confirmed that if the radius of inertia of modified PVA particles in a modified PVA composition was 18 nm immediately after the heat retention process, it is equivalent to the radius of inertia of modified PVA particles in a modified PVA composition that has been stored at 25°C for 129 days. The radius of inertia of modified PVA particles in a modified PVA composition that has undergone a heat retention process shows little change over time. For example, the radius of inertia (Rg1) of the modified PVA composition immediately after the heat retention process is equivalent to the radius of inertia (Rg) after storage at 25°C for 129 days. 1’ The rate of change of ) (Rg 1’ The Rg1 value is between 100% and 120%.

[0084] The radius of inertia of modified PVA particles in a modified PVA composition can be measured, for example, by static light scattering using a DLS-8000 model manufactured by Otsuka Electronics Co., Ltd.

[0085] The electrical conductivity of a modified PVA composition varies depending on the type, molecular weight, and concentration of the modified PVA, so it cannot be stated definitively. However, it is preferable that there is no significant change between the electrical conductivity of the modified PVA composition before the heat retention process (Ec0) and the electrical conductivity of the modified PVA composition after the heat retention process (Ec1). Ec1 tends to be larger than Ec0, but if it becomes too large, it is thought that a change has occurred in the structure of the modified PVA. The rate of change of Ec1 from Ec0 (Ec1 / Ec0) is preferably 105% or less, more preferably 104% or less, and even more preferably 103% or less. The above rate of change may also be, for example, 102% or less, or 101% or less. The electrical conductivity of the modified PVA composition can be measured using, for example, a Horiba Model DS-72.

[0086] As described above, the modified PVA composition used during the heat retention process may contain known additives, but it is preferable to add the additives after the heat retention process to avoid the additives changing over time due to the heat retention process.

[0087] In one aspect of the present invention, a filtration step may be provided to filter the modified PVA composition after the heat retention step and before the mixing step in which the modified PVA composition is mixed with other components. By filtering the modified PVA composition after the heat retention step, the filterability of the polishing composition containing the modified PVA composition is further improved, making it possible to reduce surface defects in the object to be polished.

[0088] (2) Mixing step of mixing the modified PVA composition with other components The method for producing the polishing composition of the present invention preferably further includes a mixing step of mixing the modified PVA composition with other components. That is, it is preferable that the polishing composition is prepared by mixing the modified PVA composition with other components. Here, in addition to the modified PVA composition, the polishing composition may optionally further include known additives such as abrasive grains, surfactants, water-soluble polymers other than modified PVA, modified PVA different from the aforementioned modified PVA, thickeners, pH adjusters, metal corrosion inhibitors, oxidizing agents, preservatives, fungicides, and complexing agents (chelating agents). The modified PVA different from the aforementioned modified PVA may or may not undergo the heat retention step disclosed herein. These additives may be added and mixed in the dissolution step of the modified PVA and the heat retention step of the modified PVA composition, but as described above, it is preferable to mix them with the modified PVA composition that has undergone the heat retention step. Here, the additives may, for example, be added directly to the modified PVA composition in powder form, or the modified PVA composition may be mixed with a solution containing the additives.

[0089] The polishing composition preferably contains a pH adjuster. In this case, the polishing composition comprises a modified PVA composition and a pH adjuster. The polishing composition may or may not contain abrasive particles. If the polishing composition contains abrasive particles, the abrasive particles may be added directly to the modified PVA composition as powder, or a solution containing abrasive particles may be added to the modified PVA composition. Therefore, in one embodiment, the method for producing the polishing composition includes a mixing step of adding a pH adjuster to the modified PVA composition after a heat retention step. In another embodiment, the method for producing the polishing composition includes a mixing step of adding abrasive particles and a pH adjuster to the modified PVA composition after a heat retention step.

[0090] In one embodiment, the polishing composition may further contain a solvent other than water. The solvent added in the mixing step is added in addition to the water contained in the modified PVA composition. When a solvent is added in the mixing step, the polishing composition will contain water derived from the modified PVA composition and the solvent as a dispersion medium.

[0091] The content of modified PVA in the concentrated solution of the polishing composition obtained after the mixing step is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass. Furthermore, the content of modified PVA in the polishing composition obtained after the mixing step is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. When the content of modified PVA is within the above range, the viscosity of the polishing composition does not become excessively high, and a high filtration rate can be obtained, which is preferable.

[0092] The method of mixing the modified PVA composition and the additives is not particularly limited. For example, the components constituting the polishing composition (for example, the modified PVA composition, abrasive grains, pH adjuster, and solvent) can be mixed using a well-known mixing device such as a vane stirrer, ultrasonic disperser, or homomixer. The manner in which these components are mixed is not particularly limited; for example, all components may be mixed at once, or they may be mixed in an appropriately set order.

[0093] The following describes preferred embodiments of abrasive particles, surfactants, water-soluble polymers other than modified PVA, pH adjusters, chelating agents, metal corrosion inhibitors, oxidizing agents, preservatives, fungicides, and solvents that may be included in the polishing composition.

[0094] (Abrasive grains) Abrasive particles work by mechanically polishing the surface of the object to be polished. The material and properties of abrasive particles are not particularly limited and can be appropriately selected according to the purpose and manner of use of the polishing composition. Examples of abrasive particles include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include oxide particles such as silica particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and red iron oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; and carbonates such as calcium carbonate and barium carbonate. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles and poly(meth)acrylic acid particles (where (meth)acrylic acid comprehensively refers to acrylic acid and methacrylic acid), and polyacrylonitrile particles. Such abrasive grains may be used individually or in combination of two or more types. Furthermore, synthetic abrasive grains or commercially available abrasive grains may be used.

[0095] As the abrasive grains, inorganic particles are preferred, and among these, particles made of metal or metalloid oxides are preferred, with silica particles being particularly preferred. In polishing compositions that can be used for polishing (e.g., finish polishing) substrates having a silicon surface, such as silicon wafers described later, it is particularly significant to use silica particles as abrasive grains. The technology disclosed herein can preferably be carried out, for example, in a manner in which the abrasive grains consist substantially of silica particles. Here, "substantially" means that 95% by mass or more (preferably 98% by mass or more, more preferably 99% by mass or more, and may be 100% by mass) of the particles constituting the abrasive grains are silica particles.

[0096] Specific examples of silica particles include colloidal silica, fumed silica, and precipitated silica. Silica particles can be used individually or in combination of two or more types. Colloidal silica is particularly preferred because it easily yields a polished surface with excellent surface quality after polishing. As colloidal silica, for example, colloidal silica produced from water glass (sodium silicate) by ion exchange or colloidal silica produced by alkoxide method (colloidal silica produced by hydrolysis condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used individually or in combination of two or more types.

[0097] Furthermore, the abrasive grains may be surface-modified. Specifically, the silica particles may have cationic groups. That is, the silica particles may be cationic-modified silica particles or cationic-modified colloidal silica. As a colloidal silica having cationic groups (cationically modified colloidal silica), colloidal silica with amino groups immobilized on its surface is preferred. A method for producing such colloidal silica having cationic groups is to immobilize a silane coupling agent having amino groups, such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, and aminobutyltriethoxysilane, on the surface of silica particles, as described in Japanese Patent Application Publication No. 2005-162533. This makes it possible to obtain colloidal silica with amino groups immobilized on its surface (amino group-modified colloidal silica).

[0098] Silica particles may have anionic groups. That is, the silica particles may be anionic modified silica particles or anionic modified colloidal silica. As colloidal silica having anionic groups (anionic modified colloidal silica), colloidal silica in which anionic groups such as carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, and aluminic acid groups are immobilized on the surface is preferred. There are no particular limitations on the method for producing such colloidal silica having anionic groups, and for example, a method of reacting colloidal silica with a silane coupling agent having anionic groups at its terminals can be mentioned.

[0099] For example, if you want to immobilize sulfonic acid groups on colloidal silica, you can do so by the method described in “Sulfonic acid-functionalized silica through of thiol groups”, Chem.Commun. 246-247 (2003). Specifically, by coupling a silane coupling agent having a thiol group, such as 3-mercaptopropyltrimethoxysilane, to colloidal silica and then oxidizing the thiol group with hydrogen peroxide, you can obtain colloidal silica on which sulfonic acid groups are immobilized on the surface (sulfonic acid-modified colloidal silica).

[0100] If you want to immobilize a carboxylic acid group on colloidal silica, for example, “Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of This can be done by the method described in "Silica Gel," Chemistry Letters, 3, 228-229 (2000). Specifically, by coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to colloidal silica and then irradiating it with light, colloidal silica with immobilized carboxylic acid groups on its surface (carboxylic acid-modified colloidal silica) can be obtained.

[0101] The true specific gravity of the abrasive grain constituent material (e.g., silica constituting silica particles) is preferably 1.5 or higher, more preferably 1.6 or higher, and even more preferably 1.7 or higher. While there is no particular upper limit to the true specific gravity of silica, it is typically 2.3 or lower, for example, 2.2 or lower. The true specific gravity of the abrasive grain (e.g., silica particles) can be measured using a liquid displacement method with ethanol as the displacement solution.

[0102] The BET diameter of the abrasive grains (typically silica particles) is not particularly limited, but from the viewpoint of polishing efficiency, it is preferably 5 nm or more, more preferably 10 nm or more. From the viewpoint of obtaining a higher polishing effect (e.g., reduction of haze, removal of defects, etc.), the BET diameter is preferably 15 nm or more, and more preferably 20 nm or more (e.g., greater than 20 nm). Also, from the viewpoint of preventing scratches, the BET diameter of the abrasive grains is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 40 nm or less. The technology disclosed herein is preferable for polishing where a high-quality surface is required after polishing, as it is easy to obtain a high-quality surface (e.g., a surface with a low LPD number). As abrasive grains used in such polishing compositions, abrasive grains with a BET diameter of 35 nm or less (typically less than 35 nm, more preferably 32 nm or less, e.g., less than 30 nm) are preferred.

[0103] In this specification, the BET diameter is defined as the specific surface area (BET value) measured by the BET method, with the formula: BET diameter (nm) = 6000 / (true density (g / cm³) 3 ) × BET value (m 2 This refers to the particle size calculated by the formula ( / g). For example, in the case of silica particles, BET diameter (nm) = 2727 / BET value (nm). 2 The BET diameter can be calculated using ( / g). Specific surface area can be measured, for example, using a surface area measuring device manufactured by Micromeritex, product name "Flow Sorb II 2300".

[0104] The average secondary particle diameter of the abrasive grains is not particularly limited, but from the viewpoint of polishing efficiency, it is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, and particularly preferably 25 nm or more. From the viewpoint of obtaining a higher polishing effect, such as reduction of haze and removal of defects, the above average secondary particle diameter is preferably 30 nm or more, and more preferably 40 nm or more. Furthermore, from the viewpoint of suppressing local stress that the abrasive grains impart to the substrate surface, the average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and even more preferably 125 nm or less. The technology disclosed herein is also preferable in which abrasive grains with an average secondary particle diameter of 100 nm or less, for example less than 80 nm, and even 65 nm or less (typically 50 nm or less) are used, as it is easier to obtain a higher quality surface, and the stability of the polishing composition is improved by the reduction in the average secondary particle diameter of the abrasive grains that can be implemented. The average secondary particle size of the abrasive grains can be measured, for example, by dynamic light scattering using the "UPA-UT151" model manufactured by Nikkiso Co., Ltd.

[0105] The shape (outer form) of the abrasive grains may be spherical or non-spherical. Specific examples of non-spherical particles include peanut-shaped (i.e., the shape of a peanut shell), cocoon-shaped, konpeito-shaped, and rugby ball-shaped particles. For example, abrasive grains in which most of the particles are peanut-shaped or cocoon-shaped may be preferably used.

[0106] While not particularly limited, the average aspect ratio of the major axis to minor axis of the abrasive grains (average aspect ratio) is, in principle, 1.0 or higher, preferably 1.05 or higher, and more preferably 1.1 or higher. Increasing the average aspect ratio can lead to higher polishing efficiency. Furthermore, from the viewpoint of reducing scratches, the average aspect ratio of the abrasive grains is preferably 3.0 or lower, more preferably 2.0 or lower, and even more preferably 1.5 or lower.

[0107] The shape (outer shape) and average aspect ratio of abrasive grains can be determined, for example, by electron microscopy observation. A specific procedure for determining the average aspect ratio is to use a scanning electron microscope (SEM) to draw the smallest rectangle circumscribing each grain image for a predetermined number of abrasive grains (e.g., 200 grains) whose individual grain shapes can be recognized. Then, for each rectangle drawn for each grain image, the ratio of the major axis to the minor axis is calculated by dividing the length of the major side (major axis value) by the length of the minor side (minor axis value). The average aspect ratio can be obtained by taking the arithmetic mean of the aspect ratios of the predetermined number of grains.

[0108] The abrasive content in the diluent of the polishing composition is not particularly limited, but is typically 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.10% by mass or more, for example 0.15% by mass or more. A higher polishing speed can be achieved by increasing the abrasive content. From the viewpoint of the dispersion stability of the abrasive in the polishing composition, the above content is usually appropriate to be 10% by mass or less, preferably 7% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, for example 1% by mass or less, and may also be 0.7% by mass or less. In a preferred embodiment, the above content may be 0.5% by mass or less, 0.4% by mass or less, or 0.2% by mass or less.

[0109] (Surfactants) The polishing composition may contain a surfactant to the extent that the effects of the present invention are not significantly hindered. Any surfactant can be used: anionic, cationic, nonionic, or amphoteric. The polishing composition disclosed herein can be carried out in a substantially surfactant-free manner.

[0110] Anionic surfactants are classified, for example, into sulfate-based, sulfonic acid-based, phosphoric acid-based, phosphonic acid-based, and carboxylic acid-based types. Specific examples of anionic surfactants include alkyl sulfate esters, polyoxyethylene alkyl sulfate esters, polyoxyethylene alkyl sulfate, alkyl sulfate, alkyl ether sulfate esters, higher alcohol sulfate esters, alkyl phosphate esters, alkylbenzene sulfonic acid, α-olefin sulfonic acid, alkyl sulfonic acid, styrene sulfonic acid, alkylnaphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, polyoxyethylene alkyl ether acetate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phosphate ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, or salts thereof, taurine-based surfactants, sarcosinate-based surfactants, isethionate-based surfactants, N-acyl acid amino acid-based surfactants, higher fatty acid salts, acylated polypeptides, etc. Specific examples of alkyl sulfonic acid or its salts include dodecyl sulfonic acid and dodecyl sulfonate salts.

[0111] Cationic surfactants are classified into, for example, polyoxyethylene alkylamines, alkyl alkanolamides, alkylamine salts, amine oxides, quaternary ammonium salts, and tertiary amide amine type surfactants. Specific examples of cationic surfactants include coconutamine acetate, stearylamine acetate, lauryldimethylamine oxide, dimethylaminopropyl stearate, alkyltrimethylammonium salts, alkyldimethylammonium salts, and alkylbenzyldimethylammonium salts.

[0112] Specific examples of amphoteric surfactants include alkyl betaine-based surfactants and alkylamine oxide-based surfactants. Examples of amphoteric surfactants include cocobetaine, lauramidopropyl betaine, cocamidopropyl betaine, sodium lauroamphoacetate, sodium cocoamphoacetate, coconut oil fatty acid amidopropyl betaine, and lauryl betaine (lauryldimethylaminoacetate betaine).

[0113] Specific examples of nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives such as polyoxyethylene alkyl ethers, polyoxyethylene alkylamines, polyoxyalkylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyalkylene adducts); copolymers of multiple types of oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, alternating copolymers); sucrose fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, alkyl alkanolamides, etc. These surfactants may be used individually or in combination of two or more types.

[0114] The number of carbon atoms in the alkyl group of the polyoxyethylene alkyl ether used herein is not particularly limited. For example, the number of carbon atoms in the alkyl group is preferably 5 or more, more preferably 6 or more, even more preferably 7 or more, particularly preferably 8 or more, specifically 9 or more. For example, the number of carbon atoms in the alkyl group is preferably 12 or less, more preferably 11 or less. The number of carbon atoms in the alkyl group is, for example, 10. Furthermore, the number of moles of ethylene oxide added to the polyoxyethylene alkyl ether is not particularly limited, but is preferably 4 or more, more preferably 5 or more, preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, particularly preferably 7 or less. From the viewpoint of reducing surface defects, polyoxyethylene octyl ether with an ethylene oxide addition mole number of 4 to 10 (e.g., 6) can be preferably used as the surfactant in the polishing composition disclosed herein.

[0115] Specific examples of nonionic surfactants containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblocks, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, and Examples include polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

[0116] The weight-average molecular weight (Mw) of the surfactant is preferably less than 2000, more preferably 1500 or less, even more preferably 700 or less, and particularly preferably 500 or less. Furthermore, if the surfactant is a polyoxyalkylene derivative, its Mw is preferably 100 or more, more preferably 200 or more, and even more preferably 300 or more. A polishing composition containing a surfactant having an Mw within this range effectively reduces surface defects. The weight-average molecular weight of the surfactant can be determined from its chemical formula.

[0117] The concentration of the surfactant in the diluent of the polishing composition is not particularly limited and can be, for example, 0.00001% by mass or more, preferably 0.00005% by mass or more. Furthermore, the concentration of the surfactant in the polishing composition and / or surfactant is usually preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and may be 0.05% by mass or less. In one preferred embodiment, the concentration of the surfactant in the polishing composition and / or surfactant may be 0.00001% by mass or more and 0.05% by mass or less, or 0.00005% by mass or more and 0.01% by mass or less. In another preferred embodiment, the concentration of the surfactant in the polishing composition and / or surfactant may be 0.0001% by mass or more and 0.005% by mass or less.

[0118] The molar ratio of modified PVA to surfactant in the polishing composition is preferably 5 or less, and more preferably 2 or less. In this embodiment, the molar ratio of modified PVA to surfactant is usually 0.01 or more, preferably 0.02 or more, more preferably 0.03 or more, and even more preferably 0.04 or more. When modified PVA and surfactant are included in such a blending ratio, the substrate surface is adequately protected, and surface defects are easily reduced.

[0119] (Water-soluble polymers other than modified PVA) Other water-soluble polymers besides modified PVA include compounds containing hydroxyl groups, carboxyl groups, acyloxy groups, sulfo groups, amide structures, imide structures, quaternary ammonium structures, heterocyclic structures, vinyl structures, etc., in their molecules. Other water-soluble polymers besides modified PVA may also be unmodified PVA (unmodified polyvinyl alcohol). For unmodified PVA, the same form as modified PVA is preferably applied, except that it is unmodified. Furthermore, other water-soluble polymers besides modified PVA may be natural polymer compounds, semi-synthetic polymer compounds, or synthetic polymer compounds. Natural polymer compounds are not particularly limited, but polysaccharides are preferred. Semi-synthetic polymer compounds are not particularly limited, but cellulose derivatives, starch derivatives, etc. Synthetic polymer compounds are not particularly limited, but polymers having oxyalkylene units, polymers containing nitrogen atoms, etc. One embodiment of a polymer containing nitrogen atoms may be an N-vinyl type polymer or an N-(meth)acryloyl type polymer. Specific examples of these compounds will be described later.

[0120] Polysaccharides are not particularly limited, but examples include carrageenan, xanthan gum, glycogen, alginic acid, pectin, pectic acid, starch, starch derivatives, amylose, amylopectin, agar, curdlan, pullulan, guar gum, konjac mannan, and tamarind gum.

[0121] Cellulose derivatives are not particularly limited, but examples include hydroxyethylcellulose (hereinafter also simply referred to as "HEC"), hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, and other cellulose derivatives, as well as pullulan. One type of cellulose derivative may be used alone, or two or more types may be used in combination. Here, a cellulose derivative is defined as a compound that contains a β-glucose unit as its main repeating unit, and in which some of the hydroxyl groups of cellulose are substituted with other substituents.

[0122] The starch derivative is not particularly limited, but examples include cationic starch, phosphate starch, and carboxymethyl starch salts. Here, a starch derivative is a polymer containing α-glucose units as its main repeating unit.

[0123] The polymer having oxyalkylene units is not particularly limited, but examples include polyethylene oxide (PEO), polypropylene oxide (PPO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO. Among these, block copolymers of EO and PO or random copolymers of EO and PO are preferred. The block copolymer of EO and PO may be a diblock or triblock containing a PEO block and a polypropylene oxide (PPO) block. Examples of the above triblock include PEO-PPO-PEO type triblocks and PPO-PEO-PPO type triblocks. Among these, the PEO-PPO-PEO type triblock is more preferred.

[0124] In a block copolymer or random copolymer of EO and PO, the molar ratio [EO / PO] of EO and PO constituting the copolymer is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more, from the viewpoint of solubility in water and washability. In a further preferred embodiment, the above molar ratio [EO / PO] is, for example, 5 or more.

[0125] Examples of N-vinyl polymers include polymers containing repeating units derived from monomers having nitrogen-containing heterocyclic rings (e.g., lactam rings). Examples of such polymers include homopolymers and copolymers of N-vinyl lactam monomers (e.g., copolymers in which the copolymerization ratio of N-vinyl lactam monomers exceeds 50% by mass), and homopolymers and copolymers of N-vinyl chain amides (e.g., copolymers in which the copolymerization ratio of N-vinyl chain amides exceeds 50% by mass).

[0126] Specific examples of N-vinyllactam monomers (i.e., compounds having a lactam structure and an N-vinyl group within a single molecule) include N-vinylpyrrolidone (VP), N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam (VC), N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholindione. Specific examples of polymers containing N-vinyllactam monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), block copolymers containing polymer chains containing one or both of VP and VC, alternating copolymers, and graft copolymers.

[0127] Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide.

[0128] Examples of N-(meth)acryloyl polymers include homopolymers and copolymers of N-(meth)acryloyl monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl monomers exceeds 50% by mass). Examples of N-(meth)acryloyl monomers include chain amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group.

[0129] Examples of chain-like amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of polymers containing chain-like amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by mass).

[0130] Examples of cyclic amides having an N-(meth)acryloyl group include N-acryloylmorpholine, N-acryloylthiomorpholine, N-acryloylpiperidine, N-acryloylpyrrolidine, N-methacryloylmorpholine, N-methacryloylpiperidine, and N-methacryloylpyrrolidine. An example of a polymer containing a cyclic amide having an N-(meth)acryloyl group as a monomer unit is acryloylmorpholine polymer (PACMO). Typical examples of acryloylmorpholine polymers include homopolymers of N-acryloylmorpholine (ACMO) and copolymers of ACMO (for example, copolymers in which the copolymerization ratio of ACMO exceeds 50% by mass). In acryloylmorpholine polymers, the ratio of the number of moles of ACMO units to the total number of moles of repeating units is usually 50% or more, and is appropriately 80% or more (for example, 90% or more, typically 95% or more). The entire repeating unit of the water-soluble polymer may be substantially composed of ACMO units.

[0131] Other examples of polymers containing nitrogen atoms include imine derivatives such as polyhydroxyethylacrylamide (PHEAA), poly-N-vinylimidazole (PVI), poly-N-vinylcarbazole, and poly-N-vinylpiperidine. The polymers containing nitrogen atoms may be homopolymers or copolymers, and may be used individually or in combination of two or more types.

[0132] Furthermore, water-soluble polymers other than the modified PVA mentioned above may be water-soluble polymers having at least one functional group selected from cationic groups, anionic groups, and nonionic groups in their molecules. From the viewpoint of reducing aggregates and improving washability, nonionic polymers can be preferably used as the water-soluble polymer.

[0133] Other specific examples of water-soluble polymers include polycarboxylic acids, polycarboxylic acid amides, polycarboxylic acid esters, polyphosphonic acids, polysulfonic acids such as polystyrene sulfonic acid, water-soluble polymers such as ethylene oxide polymers, vinyl polymers, and cationic polymers, as well as copolymers thereof, salts thereof, and derivatives. Specific examples of polycarboxylic acids, polycarboxylic acid amides, polycarboxylic acid esters, or polycarboxylic acid salts include polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polyammonium methacrylate salt, polysodium methacrylate salt, polymaleic acid, polyitaconic acid, polyfumaric acid, poly(p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, methyl polyacrylate, ethyl polyacrylate, polyammonium acrylate salt, sodium polyacrylate salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt, polyglyoxylic acid, and others. Specific examples of cationic polymers include cationized cellulose derivatives, cationic starch, cationized guar gum derivatives, diallyl quaternary ammonium salt / acrylamide copolymers, quaternary polyvinylpyrrolidone derivatives, and dicyandiamide-diethylenetriamine condensates. These water-soluble polymers may be used individually or in combination of two or more.

[0134] The weight-average molecular weight (Mw) of water-soluble polymers is typically 4 × 10⁻⁶. 3 That's all. 5 × 10 3 It may be greater than or equal to 1 × 10 4 It may be more than 5 × 10 4 It may be more than 10 x 10 4 It may be more than 20 × 10 4 The above is also acceptable. Furthermore, the Mw of the dispersant should be 100 × 10 4 The following is also acceptable: 50 x 10 4 The following is also acceptable: 45 × 10 4 The following is also acceptable: 40 x 10 4 The following is also acceptable.

[0135] The concentration of the water-soluble polymer (excluding modified PVA) in the polishing composition is not particularly limited and can be, for example, 0.0001% by mass or more, preferably 0.0003% by mass or more. Furthermore, the concentration of the water-soluble polymer (excluding modified PVA) in the polishing composition is usually preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and may be 0.05% by mass or less. In one preferred embodiment, the concentration of the water-soluble polymer in the polishing composition may be 0.0001% by mass or more and 0.002% by mass or less, or 0.0002% by mass or more and 0.001% by mass or less. In another preferred embodiment, the concentration of the water-soluble polymer (excluding modified PVA) in the polishing composition may be 0.005% by mass or more and 0.03% by mass or less.

[0136] In the polishing composition, the molar ratio of modified PVA to the water-soluble polymer (excluding modified PVA) is preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less (for example, 4 or less). Furthermore, in this embodiment, the molar ratio of modified PVA to the water-soluble polymer (excluding modified PVA) is usually 0.01 or more, preferably 0.02 or more, and more preferably 0.03 or more. When modified PVA and water-soluble polymer (excluding modified PVA) are included in such a blending ratio, the substrate surface is adequately protected, and surface defects are easily reduced.

[0137] (pH adjuster) The polishing composition may further contain a pH adjusting agent. The pH adjusting agent is added primarily for the purpose of adjusting the pH of the polishing composition disclosed herein. The pH adjusting agent is not particularly limited as long as it is a compound having a pH adjusting function, and known compounds can be used. Examples include alkalis and acids.

[0138] In this specification, "alkali" refers to a compound that dissolves in water and increases the pH of the aqueous solution. Examples of alkalis that can be used include nitrogen-containing organic or inorganic alkalis, alkali metal hydroxides, alkaline earth metal hydroxides, various carbonates and bicarbonates, etc. Examples of nitrogen-containing alkalis include quaternary ammonium compounds, quaternary phosphonium compounds, ammonia, and amines (preferably water-soluble amines).

[0139] Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, and sodium carbonate. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole. Specific examples of quaternary phosphonium compounds include quaternary phosphonium hydroxides such as tetramethylphosphonium hydroxide and tetraethylphosphonium hydroxide.

[0140] As the quaternary ammonium compound, quaternary ammonium salts (typically strong bases) such as tetraalkylammonium salts and hydroxyalkyltrialkylammonium salts can be preferably used. The anionic component in such quaternary ammonium salts is, for example, OH - F - Cl - , Br - , I - , 4- BH 4- These are some examples. A particularly favorable example is an anion with OH -Examples include quaternary ammonium salts, i.e., quaternary ammonium hydroxides. Specific examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide; and hydroxyalkyltrialkylammonium hydroxides such as 2-hydroxyethyltrimethylammonium hydroxide (also known as choline); and so on.

[0141] Of these alkalis, at least one alkali selected from, for example, alkali metal hydroxides, quaternary ammonium hydroxides, and ammonia can be preferably used. Among these, tetraalkylammonium hydroxide (e.g., tetramethylammonium hydroxide) and ammonia are more preferred, and ammonia is particularly preferred.

[0142] In this specification, "acid" refers to a compound that dissolves in water and lowers the pH of an aqueous solution. Either inorganic or organic acids may be used as acids. Inorganic acids are not particularly limited, but examples include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Organic acids are not particularly limited, but examples include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid, as well as carboxylic acids, methanesulfonic acid, ethanesulfonic acid, and isethionic acid. Among these, maleic acid or nitric acid is more preferred, and maleic acid is even more preferred.

[0143] The content of the pH adjusting agent is not particularly limited and can be appropriately selected so that the pH of the polishing composition according to one embodiment of the present invention falls within a desired range.

[0144] In this invention, the pH of the polishing composition is not particularly limited. The pH is preferably 1.0 or higher, more preferably 2.0 or higher, typically 8.0 or higher, preferably 8.5 or higher, more preferably 9.0 or higher, even more preferably 9.3 or higher, for example 9.5 or higher. On the other hand, the pH of the polishing composition is appropriately 12.0 or lower, preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0145] (Chelating agent) The abrasive composition may further contain a chelating agent. The chelating agent may be used alone or in combination of two or more types. Examples of the above chelating agents include aminocarboxylic acid-based chelating agents and organic phosphonic acid-based chelating agents. Preferred examples of chelating agents include, for example, ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Examples of the above preservatives and fungicides include isothiazolinoline compounds, parahydroxybenzoic acid esters, phenoxyethanol, etc.

[0146] (Metal corrosion inhibitor) The polishing composition may further contain a metal corrosion inhibitor. Specific examples of metal corrosion inhibitors include nitrogen-containing heterocyclic compounds such as pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyrinidine compounds, indidine compounds, indole compounds, isoindole compounds, indazole compounds, purine compounds, quinoridine compounds, quinoline compounds, isoquinoline compounds, naphthyridine compounds, phthalazine compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, buteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, and furazan compounds. These metal corrosion inhibitors may be used individually or in combination of two or more.

[0147] (Oxidizing agent) The polishing compositions disclosed herein may further contain an oxidizing agent. Specific examples of oxidizing agents include peroxides, periodic acid, periodates, permanganates, vanadates, hypochlorites, iron oxides, and ozone. Specific examples of peroxides include hydrogen peroxide, peracetic acid, percarbonates, urea peroxide, perchloric acid, perchlorates, and persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate. These oxidizing agents may be used individually or in combination of two or more.

[0148] When using a polishing composition on a substrate having a surface made of silicon single crystal, it is preferable that the composition substantially does not contain the above-mentioned oxidizing agent. This is because if an oxidizing agent is present, the surface of the silicon substrate may be oxidized, forming an oxide film, which may reduce the effectiveness of the composition on the substrate surface. Here, substantially free of the oxidizing agent means that the oxidizing agent is not intentionally included, and it is acceptable that trace amounts of the oxidizing agent are inevitably included due to the raw materials or manufacturing process. The above trace amount means that the molar concentration of the oxidizing agent is 0.05 mol / L or less (preferably 0.01 mol / L or less, more preferably 0.005 mol / L or less). A polishing composition according to one preferred embodiment does not contain the above-mentioned oxidizing agent.

[0149] (Preservatives, fungicides) The abrasive composition may further contain preservatives and fungicides. Specific examples of preservatives and fungicides include isothiazolinoline preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, parahydroxybenzoic acid esters, and phenoxyethanol. These preservatives and fungicides may be used individually or in combination of two or more.

[0150] (solvent) Examples of solvents include water; alcohols such as methanol, ethanol, and ethylene glycol; ketones such as acetone; and mixtures thereof. Of these, water is preferred as the solvent. That is, according to a preferred embodiment of the present invention, the solvent contains water. According to a more preferred embodiment of the present invention, the solvent consists substantially of water. The term "substantially" above means that a solvent other than water may be included insofar as the objective effects of the present invention can be achieved. More specifically, it preferably consists of 90% to 100% by mass of water and 0% to 10% by mass of a solvent other than water, more preferably 99% to 100% by mass of water and 0% to 1% by mass of a solvent other than water, and even more preferably 99.5% to 100% by mass of water and 0% to 0.5% by mass of a solvent other than water. Most preferably, the solvent is water.

[0151] When used in polishing compositions, water containing as few impurities as possible is preferred as a solvent, from the viewpoint of not inhibiting the action of the components contained in the polishing composition. More specifically, pure water, ultrapure water, or distilled water obtained by removing impurity ions with an ion exchange resin and then removing foreign matter by passing it through a filter is more preferred.

[0152] The solvent content is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 55% by mass or more, based on the total mass of the concentrated polishing composition. Furthermore, the upper limit of the solvent content is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and even more preferably 98.0% by mass or less, based on the total mass of the concentrated polishing composition. In other words, in the concentrated polishing composition, the solvent content is preferably 40 to 99.9% by mass, more preferably 50 to 99.5% by mass, and even more preferably 55 to 98.0% by mass, based on the total mass of the polishing composition. Here, the solvent also includes water contained in the modified PVA composition.

[0153] (3) Filtration step of filtering the abrasive composition The method for producing the polishing composition of the present invention preferably includes a filtration step of filtering the polishing composition. The filtration step is a step of filtering the polishing composition that has undergone the above mixing step. This step can remove aggregates from the polishing composition.

[0154] The content of modified PVA in the concentrated solution of the polishing composition used in the filtration process is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.01% by mass. Furthermore, the content of modified PVA in the polishing composition is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. When the content of modified PVA is within the above range, the viscosity of the polishing composition does not become excessively high, and a high filtration rate can be obtained, which is preferable.

[0155] The filter material used for filtering abrasive compositions is not particularly limited, but examples include polypropylene, polystyrene (PS), polyethersulfone, nylon, nylon 66, cellulose, cellulose mixed ester, cellulose acetate, nitrocellulose, regenerated cellulose, polytetrafluoroethylene (PTFE), polycarbonate, glass, polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer, polyamide, triacetylcellulose, polyvinyl chloride (PVC), polysulfone, polyester, polypropylene / polyethylene, acrylic copolymer, polylactic acid, polycaprolactone, polyglycolic acid, polydioxanone, polyhydroxybutyrate, polybutadiene, polyurethane, polymethyl methacrylate, and metals.

[0156] The filter structure is not particularly limited, but examples include depth structures, pleated structures, and membrane structures.

[0157] The pore size of the filter is not particularly limited, but it is preferably 0.03 μm or larger, more preferably 0.04 μm or larger, even more preferably 0.05 μm or larger, even more preferably 0.1 μm or larger, and particularly preferably 0.2 μm or larger. A pore size of 0.03 μm or larger is preferable because it allows for a high filtration rate. Furthermore, the pore size of the filter is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less. The pore size of the filter may be 20 μm or less, 10 μm or less, 5 μm or less, or 1 μm or less. A pore size of 100 μm or less is preferable because it improves the accuracy of filtration.

[0158] The filtration method may be any of the following: natural filtration at atmospheric pressure, suction filtration, pressure filtration, or centrifugal filtration.

[0159] The filtration process may be performed two or more times. In this case, it is preferable to appropriately change the conditions such as the pore size of the filter. For example, in the first dissolution filtration, a filter with a large pore size may be used to remove coarse particles, and in the second dissolution filtration, a filter with a small pore size may be used to remove fine particles. Performing dissolution filtration two or more times makes it possible to remove impurities more efficiently.

[0160] [Modified PVA composition] The modified PVA composition produced through the heat retention process according to the present invention has suppressed aggregation and excellent filterability. Therefore, the modified PVA composition produced through the heat retention process according to the present invention is suitable for use as an abrasive composition.

[0161] [Polishing composition] The present invention provides an abrasive composition comprising a modified PVA composition produced through a heat retention process according to the present invention. That is, according to one embodiment of the present invention, an abrasive composition comprising a modified polyvinyl alcohol composition containing modified polyvinyl alcohol or a derivative thereof and water, wherein the modified polyvinyl alcohol composition is produced by a manufacturing method that includes a heat retention process of maintaining the solution temperature at 30°C or higher and less than 60°C, and the heat retention process comprises parameter A represented by the following formula:

[0162]

number

[0163] An abrasive composition is provided, which is manufactured such that the ratio is 2.0 or higher. The modified PVA composition produced through the heat retention process according to the present invention is suitable for use as an abrasive composition and can therefore be a modified PVA composition for abrasive compositions.

[0164] (polishing liquid) The polishing composition is typically supplied to a substrate in the form of a polishing solution containing the polishing composition and used to polish the substrate. Alternatively, the polishing solution may be prepared by diluting the polishing composition (typically with water), for example. Or, the polishing composition may be used as is as a polishing solution. That is, the concept of a polishing composition in the art disclosed herein encompasses both a polishing solution (working slurry) supplied to a substrate and used to polish the substrate, and a concentrated solution (i.e., a stock polishing solution) that is diluted and used as a polishing solution. Another example of a polishing solution containing the polishing composition is a polishing solution obtained by adjusting the pH of the composition.

[0165] (Concentrate) The polishing composition disclosed herein may be in a concentrated form before being supplied to the substrate. That is, the polishing composition is in the form of a concentrated polishing solution and can also be understood as a stock solution of polishing solution. Polishing compositions in such a concentrated form are advantageous in terms of convenience and cost reduction during manufacturing, distribution, and storage. The concentration ratio of the concentrated solution is not particularly limited, and for example, it can be about 2 to 100 times in terms of volume, and usually about 5 to 50 times (for example, about 10 to 40 times) is appropriate.

[0166] Such a concentrated solution can be used by diluting it at a desired timing to prepare a polishing solution (working slurry), and then supplying the polishing solution to the substrate. The dilution can be performed, for example, by adding water to the concentrated solution and mixing it.

[0167] The abrasive content in the above-mentioned concentrated liquid can be, for example, 50% by mass or less. From the viewpoint of the handling of the above-mentioned concentrated liquid (for example, the dispersion stability and filterability of the abrasive), the abrasive content in the above-mentioned concentrated liquid is usually preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less (for example, 10% by mass or less). Furthermore, from the viewpoint of convenience and cost reduction during manufacturing, distribution, storage, etc., the abrasive content can be, for example, 0.5% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, for example 3% by mass or more. In one preferred embodiment, the abrasive content may be 4% by mass or more, or 5% by mass or more.

[0168] Here, the polishing solution may be a single-component type or a multi-component type, including a two-component type. For example, the polishing solution may be prepared by mixing part A, which contains at least abrasive grains from the components of the polishing composition, and part B, which contains at least a portion of the remaining components, and then mixing and diluting these at appropriate times as needed.

[0169] [substrate] A polishing composition according to one embodiment of the present invention can be applied to polishing and / or rinsing substrates having various materials and shapes. The substrate material may be, for example, metals or metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, hafnium, cobalt, stainless steel, or alloys thereof; glassy materials such as quartz glass, aluminosilicate glass, and glassy carbon; ceramic materials such as alumina, silica, sapphire, silicon nitride, tantalum nitride, and titanium carbide; compound semiconductor substrate materials such as silicon carbide, gallium nitride, and gallium arsenide; resin materials such as polyimide resin; and so on. The substrate may also be composed of multiple materials from among these. Furthermore, the substrate may be a metal, an oxygen atom, and a silicon atom, a silicon-silicon bond, or a nitrogen atom and a silicon atom. Examples of substrates having oxygen atoms and silicon atoms include silicon oxide (SiO2), a TEOS-type silicon oxide surface produced using tetraethyl orthosilicate as a precursor (hereinafter also simply referred to as TEOS), and so on. Examples of substrates having silicon-silicon bonds include polysilicon, amorphous silicon, single-crystal silicon, n-type doped single-crystal silicon, p-type doped single-crystal silicon, and Si-based alloys such as SiGe. Examples of substrates having nitrogen atoms and silicon atoms include silicon nitride films and silicon-nitrogen bonded substrates such as SiCN (silicon carbonitride).

[0170] A polishing composition according to one embodiment of the present invention can be particularly preferably used for polishing surfaces made of silicon, typically silicon wafers. A typical example of a silicon wafer is a silicon single-crystal wafer, for example, a silicon single-crystal wafer obtained by slicing a silicon single-crystal ingot.

[0171] The substrate may be subjected to general treatments that can be applied to the substrate in an upstream process, such as lapping or etching, prior to the polishing step with the polishing composition disclosed herein.

[0172] The polishing compositions disclosed herein can be preferably used, for example, in polishing substrates (e.g., silicon wafers) whose surface roughness has been adjusted to 0.1 nm to 100 nm by an upstream process. The surface roughness Ra of the substrate can be measured, for example, using a laser scanning surface roughness meter "TMS-3000WRC" manufactured by Schmitt Measurement System Inc. It is effective to use the polishing in finish polishing or polishing immediately preceding it, and its use in finish polishing is particularly preferred. Here, finish polishing refers to the final polishing step in the substrate manufacturing process (i.e., a step after which no further polishing is performed).

[0173] [Polishing method] The polishing compositions disclosed herein can be used for polishing substrates in embodiments including, for example, the following operations. A preferred embodiment of a method for polishing a substrate (e.g., a silicon wafer) using the polishing compositions disclosed herein will be described below.

[0174] In other words, a polishing solution containing one of the polishing compositions disclosed herein is prepared. Preparing the polishing solution may involve adjusting the concentration (e.g., dilution) or pH of the polishing composition to prepare the polishing solution. Alternatively, the polishing composition may be used as is as the polishing solution.

[0175] Next, the polishing solution is supplied to the substrate and polished using a conventional method. For example, when performing final polishing of a silicon wafer, typically, the silicon wafer that has undergone the lapping process is set in a general polishing apparatus, and the polishing solution is supplied to the surface of the silicon wafer to be polished through the polishing pad of the apparatus. Typically, while continuously supplying the polishing solution, the polishing pad is pressed against the surface of the silicon wafer to be polished and the two are moved relative to each other (for example, by rotation). Through this polishing process, the polishing of the substrate is completed.

[0176] (Polishing pad) The polishing pad used in the above polishing process is not particularly limited. For example, polishing pads of foamed polyurethane type, nonwoven fabric type, suede type, etc., can be used. Each polishing pad may or may not contain abrasive grains. Generally, polishing pads that do not contain abrasive grains are preferred.

[0177] [Washing] A substrate polished with a polishing composition according to one embodiment of the present invention is typically cleaned. Cleaning can be performed using a suitable cleaning solution. The cleaning solution used is not particularly limited, and for example, SC-1 cleaning solution, SC-2 cleaning solution, etc., which are common in fields such as semiconductors, can be used. An example of an SC-1 cleaning solution is a mixture of ammonium hydroxide (NH4OH), hydrogen peroxide (H2O2), and water (H2O). An example of an SC-2 cleaning solution is a mixture of HCl, H2O2, and H2O. The temperature of the cleaning solution can be, for example, in the range of room temperature or higher, up to about 90°C. Room temperature is typically about 15°C to 25°C. From the viewpoint of improving the cleaning effect, a cleaning solution of about 40°C to 85°C can be preferably used. [Examples]

[0178] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples, the term "parts" is used, but unless otherwise specified, it refers to "parts by mass".

[0179] [Preparation of Modified PVA Composition] (Modified PVA composition A1) An aqueous solution of acetal-modified polyvinyl alcohol (weight-average molecular weight 13,000, degree of acetalization 30 mol% (degree of saponification 85-88 mol%), cloud point: 52°C) at room temperature (25°C) was added to a 50 mL container (solid content concentration 20.5% by mass). This was designated as modified PVA composition A1, acetal-modified PVA composition (concentration 20% by mass).

[0180] (Modified PVA composition A2) 85.4 parts of water at room temperature (25°C) were added to a 50 mL container, followed by 14.6 parts of acetal-modified polyvinyl alcohol (weight-average molecular weight 13,000, degree of acetalization 30 mol% (degree of saponification 85-88 mol%), cloud point: 52°C) (solid content concentration 20.5% by mass). The container was then shaken by hand to dissolve the modified PVA, obtaining modified PVA composition A2, acetal-modified PVA composition (concentration 3% by mass).

[0181] (Modified PVA composition A3) Modified PVA composition A3 (acetal-modified PVA composition (concentration 0.1% by mass)) was obtained in the same manner as the preparation of modified PVA composition A2, except that the amount of water was changed to 99.5 parts and the amount of acetal-modified polyvinyl alcohol to 0.5 parts so that the concentration of acetal-modified polyvinyl alcohol was 0.1% by mass.

[0182] (Modified PVA composition A4) An aqueous solution of alkyl-modified polyvinyl alcohol (weight-average molecular weight 6,000, butyl ether modification degree 10 mol% (saponification degree 98 mol%), cloud point: 48°C) at room temperature (25°C) was added to a 50 mL container (solid content concentration 20.4% by mass). This yielded modified PVA composition A4 (alkyl-modified PVA composition (concentration 20.4% by mass)).

[0183] [Insulation process for modified PVA composition] (Examples 1-10 and Comparative Examples 1-11: Modified PVA compositions B1-B21) 20 mL each of the modified PVA compositions A1-A4 obtained above was placed in a 50 mL container, and the container was left standing in a chamber maintained at the temperature shown in Table 1. After confirming that the solution temperature of the modified PVA compositions A1-A4 in the container was the same as the chamber temperature, a heat retention process was carried out by leaving the modified PVA compositions A1-A4 standing for the time shown in Table 1. After the heat retention process was carried out for the predetermined time, the modified PVA compositions were removed from the chamber and left to stand until they reached room temperature (25°C) to obtain the modified PVA compositions B1-B21 of Examples 1-10 and Comparative Examples 1-11.

[0184] [Filtration experiment of modified PVA composition] Filtration experiments were performed on the modified PVA compositions B1-B21 of Examples 1-10 and Comparative Examples 1-11, which underwent a heat retention process under each heating condition. Each modified PVA composition B1-B21 was diluted with water to prepare filtration samples B1-B21 with a modified PVA concentration of 2% by mass. Using 50 mL of each sample B1-B21, the samples were passed through a filter (filter material: polyethersulfone, samples B1-B17: filter pore size 0.1 μm, samples B18-B21: filter pore size 0.2 μm) at room temperature (25°C) under a suction pressure of 0.005 MPa, and the time taken for the samples to pass through the filter was measured. The results for the modified PVA compositions B1-B9 and B11-B17 of Examples 1-9 and Comparative Examples 2-8 are shown as a relative evaluation, with the filtration time for modified PVA composition B10 of Comparative Example 1 set as the baseline (100%). Furthermore, the results for Example 10 and Comparative Examples 10 and 11 modified PVA compositions B18, 20, and 21 are shown as a relative evaluation with the filtration time of Comparative Example 9's modified PVA composition B19 set as the baseline (100%). A smaller value indicates better filterability. The results are shown in Table 1.

[0185] [Stability of Modified PVA Compositions] For each heating condition, the modified PVA compositions B1 to B21 of Examples 1 to 10 and Comparative Examples 1 to 11, after undergoing a heat retention process, were visually inspected for the presence of sediment at the bottom of the container. The results are shown in Table 1.

[0186] [Preparation of polishing compositions containing modified PVA compositions] Polishing compositions C1 and C2 were prepared using modified PVA composition B6 from Example 6 and modified PVA composition B10 from Comparative Example 1. The polishing compositions were prepared by the following procedure.

[0187] First, a concentrated solution of the polishing composition according to this example was prepared by mixing abrasive grains, a modified PVA composition, a basic compound, a surfactant, and deionized water. Modified PVA composition B6 or B9 was used as the modified PVA composition, colloidal silica (average primary particle size: 25 nm) was used as the abrasive grains, ammonia was used as the basic compound, and polyoxyalkylene alkyl ether was used as the surfactant. By diluting the obtained concentrated solution of the polishing composition with deionized water (DIW) at a volume ratio of 20, a polishing composition according to this example was obtained with an abrasive grain concentration of 0.18%, a modified PVA concentration of 0.009%, a basic compound concentration of 0.005%, and a surfactant concentration of 0.0002%. The pH of polishing compositions C1 and C2 was 9.8-10.3 (liquid temperature: 25°C).

[0188] [Polishing silicon wafers] "Second polishing process" For the object to be polished, a silicon wafer, which is a semiconductor substrate, was polished using a secondary polishing composition under the following conditions. • Composition of the secondary polishing composition: Assuming a total of 100 parts, 0.9 parts silica abrasive grains (average primary particle size: 35 nm), 0.06 parts potassium hydroxide, • Silicon wafer (a commercially available 300mm diameter silicon single crystal wafer that has been wrapped and etched, conduction type: P-type, crystal orientation: <100> COP (Crystal Originated Particle) free).

[0189] -Secondary polishing conditions- Polishing equipment: Single-wafer polishing machine, model "PNX 332B", manufactured by Okamoto Machine Tool Works, Ltd. Polishing pad: Nitta DuPont product name "SUBA400" Grinding load: 20kPa Polishing plate rotation speed: 20 rpm Carrier rotation speed: 20 rpm Supply of polishing composition: flow-through Polishing composition supply amount: 1L / min Temperature of polishing composition X: 20℃ Surface plate cooling water temperature: 20℃ Polishing time: 120 seconds.

[0190] "Finishing polishing process" After polishing the silicon wafer surface in the secondary polishing process described above, the silicon wafer was removed from the polishing platen. Subsequently, within the same polishing apparatus, the polished silicon wafer was mounted on another polishing platen, and a finish polishing treatment was performed on the surface of the polished silicon wafer using the polishing compositions C1 and C2 prepared above, under the following conditions.

[0191] -Finishing polishing conditions- Polishing equipment: Single-wafer polishing machine, model "PNX 332B", manufactured by Okamoto Machine Tool Works, Ltd. Polishing pad: Manufactured by Fujibo Ehime Co., Ltd. Product name: "POLYPAS27NX" Grinding load: 20kPa Polishing plate rotation speed: 52 rpm Carrier rotation speed: 50 rpm Supply of polishing composition: flow-through Polishing composition supply amount: 1.5L / min Temperature for polishing compositions C1 and C2: 20°C Surface plate cooling water temperature: 20℃ Polishing time: 240 seconds.

[0192] "Washing process" A first cleaning tank (equipped with an ultrasonic transmitter) containing a cleaning solution of NH4OH (29% by mass aqueous solution):H2O2 (31% by mass aqueous solution):deionized water = 2:5.3:48 (volume ratio) maintained at 70°C, and a second cleaning tank containing ultrapure water at 25°C were prepared. The silicon wafer, after the above-mentioned finishing polishing, was immersed in the first cleaning tank for 6 minutes, then in the second cleaning tank for 15 minutes, then again in the first cleaning tank for 6 minutes, and finally in the second cleaning tank for 16 minutes, after which it was dried to obtain a sample for surface defect evaluation.

[0193] "Surface defect evaluation" The silicon wafers after the above cleaning process were used as samples for surface defect evaluation and were evaluated according to the evaluation method described below. The results are shown in Table 1.

[0194] -Evaluation Method- Inspection device: KLA-Tencor Co., Ltd., product name "SURFSCAN SP5" Measurement mode: DC mode Evaluation Method and Criteria: The number of defects exceeding 17 nm was measured in the remaining portion of one side of the test specimen, excluding a 5 mm wide section from the outer edge (the section from 0 mm to 5 mm wide, with the outer edge set to 0 mm). The number of defects when using polishing composition C1 was evaluated against the number of defects when using polishing composition C2, which was set as the baseline (100). A lower number of defects indicates fewer surface scratches, roughness, and residues, and thus less surface disturbance.

[0195] [Table 1]

[0196] As shown in Table 1, modified PVA compositions B1-B9 and B18 (Examples 1-10), which underwent a heat retention process at a temperature between 30°C and 60°C and with parameter A of 2 or higher, showed significantly improved filterability. Modified PVA compositions B11-B12 (Comparative Examples 1-3), which underwent a heat retention process with parameter A less than 2, showed no improvement in filterability. Furthermore, modified PVA compositions B13-B17, B20 and B21 (Comparative Examples 4-8, 10 and 11), which underwent a heat retention process at 60°C or higher, showed precipitate formation after the heat retention process, indicating poor stability.

[0197] It was also found that polishing with a polishing composition containing a modified PVA composition B6, which has undergone a heat retention process at a temperature of 30°C to less than 60°C and parameter A is 2 or higher, suppresses surface defects in the object being polished.

[0198] [Radius of inertia of modified PVA and its change over time] For the modified PVA compositions A1 and A4 obtained above, a heat retention process was carried out under the conditions shown in Table 2, and the radius of inertia of the modified PVA in the obtained modified PVA compositions was measured. The radius of inertia was measured before the heat retention process, immediately after the heat retention process, and after a certain period of time had elapsed after the heat retention process. The radii of inertia are as follows: radius of inertia of modified PVA before the heat retention process (Rg0), radius of inertia of modified PVA immediately after the heat retention process (Rg1), and radius of inertia of modified PVA after a certain period of time had elapsed after the heat retention process (Rg 1’ The measurement procedure involved preparing an aqueous solution of modified PVA at a concentration of 1 mg / mL. Each prepared sample was measured at 10-degree intervals within a measurement angle range of 30 to 150 degrees using a light scattering photometer "DLS-8000" (manufactured by Otsuka Electronics Co., Ltd.), and the radius of inertia (nm) was calculated by single-concentration plot analysis. The results are shown in Table 2. Table 2 shows the radius of inertia (Rg1, Rg1) of modified PVA immediately after the heat retention process and after a certain period of time. 1’ Regarding ), the relative value (rate of change Rg1 / Rg) is set with the radius of inertia (Rg0) of the modified PVA before the heat retention process set to 100%. 0、 Rg 1’ (Rg0) and the radius of inertia (Rg) of the modified PVA after a certain period of time following the heat retention process. 1’ Regarding ), the relative value (rate of change Rg) is set with the radius of inertia (Rg1) of the modified PVA immediately after the heat retention process as 100%. 1’ The Rg1 value was also shown. It can be seen that the radius of inertia of the modified PVA decreases by performing the heat retention process, and remains decreased even after a certain period of time has elapsed.

[0199] [Table 2]

[0200] [Electrical conductivity of modified PVA composition] The electrical conductivity of the modified PVA compositions B2, B3, B6, B10, and B14-16 obtained above was measured. Note that modified PVA composition B10 (Comparative Example 1) is a modified PVA composition that did not undergo a heat retention process. Electrical conductivity was measured at a liquid temperature of 25°C using a conductivity meter, model "DS-12," manufactured by Horiba, Ltd. The results obtained (Electrical conductivity (E)) are shown below. C1)) the electrical conductivity (E) of modified PVA composition B10 (Comparative Example 1) that has not undergone the heat retention process. C0 (E) is a relative value with 100%. C1 / E C0 The relative values ​​of electrical conductivity (E) are shown in Table 3. C1 / E C0 When this exceeds 105%, it can be said that a change has occurred in the structure of the modified PVA.

[0201] [Table 3]

[0202] As described above, it has been shown that by performing a predetermined heat retention step (a heat retention step at a temperature of 30°C or higher and less than 60°C, and in which parameter A is 2 or higher) on a modified PVA composition, a polishing composition can be obtained in which the filterability is significantly improved and surface defects (e.g., LPD: Light Point Defects, etc.) can be reduced. This shows that the method for manufacturing the polishing composition of the present invention can greatly improve the surface quality of a substrate.

Claims

1. A method for producing an abrasive composition comprising a modified polyvinyl alcohol composition containing modified polyvinyl alcohol or a derivative thereof and water, The modified polyvinyl alcohol composition includes a heat retention step of maintaining the solution temperature at 30°C or higher and less than 60°C. The aforementioned heat retention process involves parameter A, which is represented by the following formula: 【Number 1】 The process is carried out so that the result is 2.0 or higher. The proportion of moles of repeating units other than vinyl alcohol units in the modified polyvinyl alcohol or its derivative is 80% or less, and the degree of saponification is 70 mol% or more and 100 mol% or less. A method for producing an abrasive composition, wherein the rate of change (Rg 1 / Rg 0) of the radius of inertia of the modified polyvinyl alcohol or its derivative after the heat retention step, relative to the radius of inertia of the modified polyvinyl alcohol or its derivative before the heat retention step, is 95% or less.

2. A method for producing the polishing composition according to claim 1, wherein the modified polyvinyl alcohol or its derivative is contained in an amount of 0.1% by mass or more and 40% by mass or less based on the total mass of the modified polyvinyl alcohol composition.

3. After the heat retention step, a mixing step is performed in which the modified polyvinyl alcohol composition and a pH adjusting agent are mixed. A filtration step is performed to filter the polishing composition obtained by the mixing step, A method for producing the polishing composition according to claim 1 or 2, further comprising:

4. A method for producing an abrasive composition according to any one of claims 1 to 3, wherein the heat retention step is performed for 0.5 hours or more and 200 hours or less.

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