Polishing composition, its manufacturing method, concentrated polishing liquid, and polishing method

Abstract

To provide means that reduces faults on a polishing object surface after polishing with a polishing composition.SOLUTION: A polishing composition comprises a basic compound and a water-soluble polymer, the water-soluble polymer being obtained by the steps of (1) preparing a base solution containing a base water-soluble polymer and a solvent and (2) bringing the base solution into contact with a hydrophobic resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polishing composition, a method for producing the same, a concentrated polishing liquid, and a polishing method. [Background technology]

[0002] Water-soluble polymers are used for various purposes, such as dispersants, thickeners, emulsion polymerization stabilizers, protective colloids, paints, cosmetics, water retention agents, pharmaceutical preparations, and grinding aids. Among these, hydroxyethyl cellulose, a semisynthetic polymer compound, is particularly excellent in properties such as dispersibility and thickening. Hydroxyethyl cellulose is used in addition to abrasive grains and water as a grinding aid to protect and improve the wettability of substrate surfaces, particularly in the rinsing and polishing processes of various substrates, such as semiconductor substrates represented by silicon wafers.

[0003] Patent Document 1 discloses a method for producing dried hydrophobic hydroxyethyl cellulose, which is useful as a polishing aid that can improve the polishing rate in combination with abrasive grains. Specifically, Patent Document 1 discloses that synthesized, undried hydrophobic hydroxyethyl cellulose is dried and then pulverized to obtain dried hydrophobic hydroxyethyl cellulose.

[0004] Furthermore, Patent Document 2 discloses that impurities can be removed from water-soluble cellulose used in a polishing composition to obtain a higher quality polished object. Specifically, Patent Document 2 discloses a method for removing alkali metal elements from an aqueous solution of water-soluble cellulose by contacting the cellulose with an H-type ion exchange resin and an OH-type ion exchange resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-104781 [Patent Document 2] Japanese Patent Application Publication No. 10-309660 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the development of technology, higher surface quality is now being desired for the surface condition required for polishing objects such as semiconductor substrates, semiconductor elements, and silicon wafers.

[0007] Therefore, an object of the present invention is to provide a means for reducing defects on the surface of an object to be polished after polishing with a polishing composition. [Means for solving the problem]

[0008] The above-mentioned object of the present invention is achieved by the following means: The composition includes a basic compound and a water-soluble polymer, The water-soluble polymer is (1) obtaining a raw material solution containing a raw material water-soluble polymer and a solvent; (2) contacting the raw material solution with a hydrophobic resin; The polishing composition has undergone [Effects of the Invention]

[0009] According to the present invention, a means can be provided for reducing defects on the surface of an object to be polished after polishing with a polishing composition. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing an example of a method for contacting a raw material solution containing a raw material water-soluble polymer and a solvent with a hydrophobic resin. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. Furthermore, unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20°C to 25°C) and a relative humidity of 40% RH to 50% RH.

[0012] One aspect of the present invention is a composition comprising a basic compound and a water-soluble polymer, The water-soluble polymer is (1) obtaining a raw material solution containing a raw material water-soluble polymer and a solvent; (2) contacting the raw material solution with a hydrophobic resin; The present invention relates to a polishing composition that has undergone the above-mentioned process.

[0013] The mechanism by which defects on the surface of an object to be polished after polishing with a polishing composition according to the present invention are reduced is not clear in detail, but is thought to be as follows.

[0014] Hydrophobic impurities contained in water-soluble polymers are difficult to remove by processes such as cation exchange. Furthermore, when hydrophobic impurities contained in water-soluble polymers are adsorbed onto the wafer surface during polishing, they hinder polishing of the adhering areas and cause irregularities in the polished surface, which are defects. For this reason, it has been considered difficult to reduce defects caused by hydrophobic impurities when using water-soluble polymers.

[0015] The present invention is characterized in that a raw solution containing a raw water-soluble polymer and a solvent is contacted with a hydrophobic resin. This feature allows hydrophobic impurities to be removed from the raw water-soluble polymer through hydrophobic interactions with the hydrophobic resin. As a result, by using a polishing composition containing the resulting water-soluble polymer, the hydrophobic impurities are prevented from adsorbing onto the wafer surface during polishing, thereby preventing polishing of the adhering portions. This reduces defects on the surface of the object to be polished after polishing with the polishing composition.

[0016] The above mechanism is based on speculation, and its accuracy does not affect the technical scope of the present application. This does not have any effect.

[0017] In this specification, the terms "aqueous solution" and "solution" include not only a liquid in which the water-soluble polymer is completely dissolved, but also a liquid in which at least a portion of the water-soluble polymer is dissolved. In this case, the remaining water-soluble polymer may be in a state of being dispersed in the solvent (undissolved). In addition, in this specification, "dissolve" refers to dissolving or dispersing.

[0018] The present invention will now be described in further detail.

[0019] (Water-soluble polymer) The polishing composition includes a water-soluble polymer that has been prepared by (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent, and (2) contacting the raw solution with a hydrophobic resin.

[0020] (1) Solution preparation process The water-soluble polymer contained in the polishing composition is prepared by (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent (solution preparation step). The solution may be prepared by dissolving the raw water-soluble polymer in a solvent to obtain a raw solution, or the raw water-soluble polymer in solution form may be used as is. The water-soluble polymer contained in the polishing composition is prepared by obtaining a raw solution containing the raw water-soluble polymer and a solvent.

[0021] ·Raw material water-soluble polymer The type of the raw material water-soluble polymer according to one embodiment of the present invention is not particularly limited as long as it is a polymer compound having water solubility.

[0022] In this specification, "water-soluble" means that the solubility in water (25°C) is 1 g / 100 ml or more, and "polymer compound" means a compound having a weight-average molecular weight of 1,000 or more. The weight-average molecular weight can be measured by gel permeation chromatography (GPC), and details of the measurement method will be described in the Examples.

[0023] The raw water-soluble polymer may be any of natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds. Natural polymer compounds are not particularly limited, but preferably include polysaccharides. Semi-synthetic polymer compounds are not particularly limited, but preferably include cellulose derivatives, starch derivatives, and the like. Synthetic polymer compounds are not particularly limited, but preferably include polymers having oxyalkylene units, polymers having structural units derived from vinyl alcohol, and polymers having nitrogen atoms. Among these, the raw water-soluble polymer preferably includes at least one of a polymer having structural units derived from vinyl alcohol and a cellulose derivative, and more preferably includes a cellulose derivative. Polishing compositions containing these polymers are likely to improve the surface quality after the polishing process. Specific examples of these compounds are listed below.

[0024] The polysaccharide is not particularly limited, and examples thereof include carrageenan, xanthan gum, etc. One type of polysaccharide may be used alone, or two or more types may be used in combination.

[0025] The polymer having an oxyalkylene unit is not particularly limited, but examples thereof 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.

[0026] Among these, block copolymers of EO and PO or random copolymers of EO and PO are preferred. The block copolymers of EO and PO may be diblock copolymers, triblock copolymers, etc., containing a PEO block and a polypropylene oxide (PPO) block. Examples of the triblock copolymers include PEO-PPO-PEO triblock copolymers and PPO-PEO-PPO triblock copolymers. Of these, PEO-PPO-PEO triblock copolymers are more preferred. In block or random copolymers of EO and PO, the molar ratio of EO to PO constituting the copolymer [EO / PO] is preferably greater than 1, more preferably 2 or greater, and even more preferably 3 or greater, from the viewpoints of water solubility, washability, etc. In a more preferred embodiment, the molar ratio [EO / PO] is, for example, 5 or greater.

[0027] The polymers having oxyalkylene units may be used singly or in combination of two or more.

[0028] A polymer having a structural unit derived from vinyl alcohol may contain only vinyl alcohol units (hereinafter also referred to as "VA units") as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units"). A polymer having a structural unit derived from vinyl alcohol may be used alone or in combination of two or more types. A vinyl alcohol unit is a structural moiety represented by the following chemical formula: -CH2-CH(OH)-. A polymer having a structural unit derived from vinyl alcohol may be a random copolymer containing VA units and non-VA units, or may be a block copolymer or a graft copolymer. A polymer having a structural unit derived from vinyl alcohol may contain only one type of non-VA unit, or may contain two or more types of non-VA units.

[0029] The polymer having structural units derived from vinyl alcohol may be unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA). Here, unmodified PVA refers to a polymer produced by hydrolysis (saponification) of polyvinyl acetate and having structural units derived from vinyl alcohol that are substantially free of repeating units other than repeating units (—CH—CH(OCOCH)—) formed by vinyl polymerization of vinyl acetate and VA units. The degree of saponification of the unmodified PVA may be, for example, 60% or more, and from the viewpoint of water solubility, may be 70% or more, 80% or more, or 90% or more. In some embodiments, unmodified PVA having a degree of saponification of 95% or more or 98% or more may be preferably used as the raw water-soluble polymer.

[0030] Non-VA units that may be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl monomers or N-(meth)acryloyl monomers, as described below, 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. A preferred example of the N-vinyl monomer is N-vinylpyrrolidone. A preferred example of the N-(meth)acryloyl monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate.

[0031] The polymer having a structural unit derived from vinyl alcohol may be a modified PVA containing a VA unit and a non-VA unit having at least one structure selected from an oxyalkylene group, a carboxy 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.

[0032] The polymer having structural units derived from vinyl alcohol may be a modified PVA in which a portion of the VA units contained in the polymer having structural units derived from vinyl alcohol are acetalized with an aldehyde compound or a ketone compound. In a preferred embodiment of the technology disclosed herein, the acetalized modified PVA is a polymer obtained by acetalization reaction of the above-mentioned non-modified PVA with an aldehyde compound.

[0033] In one embodiment of the present invention, the aldehyde compound used to produce the acetalized modified PVA is not particularly limited. In a preferred embodiment, the aldehyde compound has 1 to 7 carbon atoms, more preferably 2 to 7 carbon atoms.

[0034] Examples of the aldehyde compound include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butylaldehyde, isobutyraldehyde, t-butylaldehyde, and hexylaldehyde; and alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde. These may be used alone or in combination of two or more. Furthermore, with the exception of formaldehyde, one or more hydrogen atoms may be substituted with a halogen or the like. Among these, linear or branched alkyl aldehydes are preferred because of their high solubility in water and ease of acetalization reaction, and among these, acetaldehyde, n-propylaldehyde, n-butylaldehyde, and n-pentylaldehyde are more preferred.

[0035] In addition to the above, aldehyde compounds having 8 or more carbon atoms, such as 2-ethylhexyl aldehyde, nonyl aldehyde, and decyl aldehyde, may also be used as the aldehyde compound.

[0036] Furthermore, as a polymer having a structural unit derived from vinyl alcohol, a cationically modified polyvinyl alcohol into which a cationic group such as a quaternary ammonium structure has been introduced may be used. Examples of the cationically modified polyvinyl alcohol include those into which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, has been introduced. Furthermore, as a polymer having a structural unit derived from vinyl alcohol, a non-VA unit may have a structural moiety represented by the chemical formula: -CH2-CH(CR5(OR8)-CR6(OR9)-R7)-. Here, R5 to R7 each independently represent a hydrogen atom or an organic group, and R8 and R9 each independently represent a hydrogen atom or an R 10 -CO-(wherein, R 10 represents an alkyl group.) Such modified PVAs include modified PVAs having a 1,2-diol structure in the side chain.

[0037] The ratio of the number of moles of VA units to the number of moles of all repeating units constituting a polymer having structural units derived from vinyl alcohol may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. While not particularly limited, in some embodiments, the ratio of the number of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting a polymer having structural units derived from vinyl alcohol may be VA units. Here, "substantially 100%" means that, at least intentionally, the polymer having structural units derived from vinyl alcohol does not contain non-VA units. Typically, the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (e.g., less than 1%), including 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting a polymer having structural units derived from vinyl alcohol may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0038] The content of VA units (content by mass) in a polymer having structural units derived from vinyl alcohol 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. While not particularly limited, in some embodiments, the content of VA units may be 50% by mass or more (e.g., more than 50% by mass), 70% by mass or more, or 80% by mass or more (e.g., 90% by mass or more, 95% by mass or more, or 98% by mass or more). Substantially 100% by mass of the repeating units constituting a polymer having structural units derived from vinyl alcohol may be VA units. Here, "substantially 100% by mass" means that non-VA units are at least intentionally not included as repeating units constituting a polymer having structural units derived from vinyl alcohol, and typically means that the content of non-VA units in a polymer having structural units derived from vinyl alcohol is less than 2% by mass (e.g., less than 1% by mass). In some other embodiments, the content of VA units in a polymer having structural units derived from vinyl alcohol may be, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[0039] A polymer having a structural unit derived from vinyl alcohol may contain multiple polymer chains with different VA unit contents within the same molecule. Here, a polymer chain refers to a segment that constitutes a part of a single polymer molecule. For example, a polymer having a structural unit derived from vinyl alcohol may contain, within the same molecule, a polymer chain X having a VA unit content of more than 50% by mass and a polymer chain Y having a VA unit content of less than 50% by mass (i.e., a non-VA unit content of more than 50% by mass).

[0040] The polymer chain X may contain only VA units as repeating units, or may contain non-VA units in addition to VA units. The content of VA units in the polymer chain X 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 VA units in the polymer chain X may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting the polymer chain X may be VA units.

[0041] The polymer chain Y may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units. The content of non-VA units in the polymer chain Y 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 the polymer chain Y may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting the polymer chain Y may be non-VA units.

[0042] Examples of polymers having structural units derived from vinyl alcohol, which contain polymer chain X and polymer chain Y in the same molecule, include block copolymers and graft copolymers containing these polymer chains. The graft copolymers may be graft copolymers having a structure in which polymer chain Y (side chain) is grafted to polymer chain X (main chain), or graft copolymers having a structure in which polymer chain X (side chain) is grafted to polymer chain Y (main chain). In one embodiment, a polymer having structural units derived from vinyl alcohol, which has a structure in which polymer chain Y is grafted to polymer chain X, can be used.

[0043] Examples of the polymer chain Y include polymer chains having a repeating unit derived from an N-vinyl type monomer as the main repeating unit, polymer chains having a repeating unit derived from an N-(meth)acryloyl type monomer as the main repeating unit, polymer chains having a repeating unit derived from a vinyl dicarboxylate such as fumaric acid, maleic acid, or maleic anhydride as the main repeating unit, polymer chains having a repeating unit derived from an aromatic vinyl monomer such as styrene or naphthalene vinyl as the main repeating unit, and polymer chains having an oxyalkylene unit as the main repeating unit. In this specification, unless otherwise specified, the term "main repeating unit" refers to a repeating unit contained in an amount of more than 50% by mass.

[0044] A suitable example of the polymer chain Y is a polymer chain having an N-vinyl monomer as the main repeating unit, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl monomers in the N-vinyl polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of the polymer chain Y may be repeating units derived from N-vinyl monomers.

[0045] In this specification, examples of N-vinyl monomers include monomers having a nitrogen-containing heterocycle (e.g., a lactam ring) and N-vinyl linear amides. Specific examples of N-vinyl lactam monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione. Specific examples of N-vinyl linear amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. The polymer chain Y may be, for example, an N-vinyl polymer chain in which more than 50% by mass (e.g., 70% by mass or more, 85% by mass or more, or 95% by mass or more) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting the polymer chain Y may be N-vinylpyrrolidone units.

[0046] Another example of the polymer chain Y is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl-type monomer, i.e., an N-(meth)acryloyl-based polymer chain. The content of the repeating unit derived from an N-(meth)acryloyl-type monomer in the N-(meth)acryloyl-based polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or even 95% by mass or more. Substantially all of the polymer chain Y may be repeating units derived from an N-(meth)acryloyl-type monomer.

[0047] In this specification, examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of linear 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 cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0048] Another example of the polymer chain Y is a polymer chain containing an oxyalkylene unit as a main repeating unit, i.e., an oxyalkylene-based polymer chain. The content of the oxyalkylene unit in the oxyalkylene-based polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of the repeating units contained in the polymer chain Y may be oxyalkylene units.

[0049] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, oxybutylene units, etc. Such oxyalkylene units may be repeating units derived from the corresponding alkylene oxides. The oxyalkylene units contained in the oxyalkylene polymer chain may be one type or two or more types. For example, the oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, the oxyalkylene units may be a random copolymer of the corresponding alkylene oxides, or may be a block copolymer or a graft copolymer.

[0050] Further examples of the polymer chain Y include a polymer chain containing a repeating unit derived from an alkyl vinyl ether (e.g., a vinyl ether having an alkyl group having from 1 to 10 carbon atoms), a polymer chain containing a repeating unit derived from a monocarboxylic acid vinyl ester (e.g., a vinyl ester of a monocarboxylic acid having from 3 or more carbon atoms), a polymer chain in which some of the VA units have been acetalized with an aldehyde (e.g., an alkylaldehyde having an alkyl group having from 1 to 7 carbon atoms), and a polymer chain into which a cationic group (e.g., a cationic group having a quaternary ammonium structure) has been introduced.

[0051] The raw water-soluble polymer disclosed herein may be a polymer having structural units derived from vinyl alcohol, such as unmodified PVA, modified PVA, or a combination of unmodified and modified PVA. In an embodiment using a combination of unmodified and modified PVA, the amount of modified PVA used relative to the total amount of polymers having structural units derived from vinyl alcohol contained in the raw water-soluble polymer may be, for example, less than 95% by mass, 90% by mass or less, 75% by mass or less, 50% by mass or less, 30% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less. The raw water-soluble polymer disclosed herein may be preferably implemented, for example, in an embodiment using only one or more unmodified PVAs as the polymer having structural units derived from vinyl alcohol.

[0052] The polymers having structural units derived from vinyl alcohol may be used singly or in combination of two or more.

[0053] A cellulose derivative refers to a cellulose in which some of the hydroxyl groups of cellulose have been substituted with other substituents. One type of cellulose derivative may be used alone, or two or more types may be used in combination. The cellulose derivative is not particularly limited, and examples include cellulose derivatives such as hydroxyethyl cellulose (hereinafter also simply referred to as "HEC"), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose, as well as pullulan. One type of cellulose derivative may be used alone, or two or more types may be used in combination.

[0054] The starch derivative is not particularly limited, and examples thereof include cationic starch, starch phosphate, carboxymethyl starch salt, etc. One type of starch derivative may be used alone, or two or more types may be used in combination.

[0055] The polymer having a nitrogen atom is not particularly limited, but examples thereof include poly-N-acryloylmorpholine (PACMO), poly-N-vinylpyrrolidone (PVP), polyhydroxyethylacrylamide (PHEAA), poly-N-vinylimidazole (PVI), poly-N-vinylcarbazole, poly-N-vinylcaprolactam, poly-N-vinylpiperidine, etc. Among these, from the viewpoint of reducing the haze of the object to be polished, it is preferable to include poly-N-acryloylmorpholine (PACMO). The type of polymer having a nitrogen atom may be used alone or in combination of two or more.

[0056] Among these, from the viewpoint of achieving a more pronounced defect reduction effect of the present invention, the raw water-soluble polymer is preferably a semisynthetic polymer compound or a synthetic polymer compound, and more preferably a semisynthetic polymer compound. Cellulose derivatives are further preferred, and hydroxyethyl cellulose (HEC) is particularly preferred. When hydroxyethyl cellulose is used as the raw water-soluble polymer (also referred to as "raw HEC" in this specification), a commercially available product or a synthetic product may be used. The synthesis method is not particularly limited, but examples include conventionally known methods such as a method of mixing alkali cellulose and ethylene oxide in a solvent and reacting them. The raw HEC is not particularly limited, but it is preferable to use a powder.

[0057] The weight-average molecular weight (Mw) of the raw water-soluble polymer is not particularly limited, but is preferably 1,000 or more, more preferably 10,000 or more, and even more preferably 100,000 or more. The weight-average molecular weight (Mw) of the raw water-soluble polymer is preferably 4,000,000 or less, more preferably 3,000,000 or less, even more preferably 2,000,000 or less, even more preferably 1,500,000 or less, and particularly preferably 1,000,000 or less, and can be, for example, 500,000 or less.

[0058] The raw material water-soluble polymers may be used singly or in combination of two or more.

[0059] The raw material water-soluble polymer may be a commercially available product or a synthetic product.

[0060] The content (concentration) of the raw water-soluble polymer in the raw solution is not particularly limited, but is preferably 0.00001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, and particularly preferably 0.25% by mass or more, relative to the total mass of the raw solution. The content (concentration) of the raw water-soluble polymer in the raw solution is not particularly limited, but is preferably 25% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or more, even more preferably 5% by mass or less, and particularly preferably 2% by mass or less, relative to the total mass of the raw solution. That is, in (1) above, the raw water-soluble polymer is preferably in the above-mentioned content (concentration) range relative to the total mass of the raw solution containing the raw water-soluble polymer and the solvent. A preferred embodiment of the present invention is that in (1) above, the raw water-soluble polymer is 0.1% by mass or more and 5% by mass or less, relative to the total mass of the raw solution containing the raw water-soluble polymer and the solvent. The content (concentration) of the raw water-soluble polymer in the raw solution to be applied to the contact step and cation exchange step described below is also the same as above.

[0061] ·solvent The solvent contained in the raw material solution is not particularly limited as long as it can dissolve the raw material water-soluble polymer, but preferably contains water. The water content in the solvent is not particularly limited, but is preferably 50% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass (water only) relative to the total mass of the solvent. It is preferable that the water contains as few impurities as possible to prevent contamination of the substrate and inhibition of the action of other components. For example, water with a total transition metal ion content of 100 ppb or less is preferred. The purity of the water can be increased by, for example, removing impurity ions using an ion exchange resin, removing foreign matter using a filter, or by distillation. Specifically, deionized water (DIW), pure water, ultrapure water, distilled water, etc. are preferably used as the water.

[0062] Furthermore, the solvent may be an organic solvent or a mixed solvent of water and an organic solvent, provided that it can improve the solubility of the raw water-soluble polymer. The organic solvent is not particularly limited, and known organic solvents can be used. When a mixed solvent of water and an organic solvent is used, organic solvents that are miscible with water, such as acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, are preferably used. When an organic solvent is used, water and the organic solvent may be mixed, and each component may be added to the resulting mixed solvent and dissolved therein. Alternatively, these organic solvents may be used without mixing with water, and the raw water-soluble polymer may be dissolved therein, and then mixed with water. These organic solvents may be used alone or in combination of two or more.

[0063] Basic compounds The raw material solution may contain a basic compound, which refers to a compound that has the function of increasing the pH of an aqueous solution when added to the aqueous solution.

[0064] The type of basic compound is not particularly limited, and examples thereof include nitrogen-containing organic or inorganic basic compounds, hydroxides of alkali metals or Group 2 metals, various carbonates and bicarbonates, quaternary ammonium hydroxides or their salts, ammonia, amines, etc. The basic compound preferably includes at least one selected from the group consisting of nitrogen-containing organic or inorganic basic compounds, hydroxides of alkali metals or Group 2 metals, various carbonates and bicarbonates, quaternary ammonium hydroxides or their salts, ammonia, and amines. Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of Group 2 metal hydroxides include calcium hydroxide, strontium hydroxide, and barium hydroxide. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, and sodium carbonate. Specific examples of quaternary ammonium hydroxides or their salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, and tetrabutylammonium hydroxide. 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. From the viewpoint of removing the anti-mold agent, the basic compound is preferably at least one selected from the group consisting of ammonia, quaternary ammonium hydroxide, quaternary ammonium hydroxide salts, carbonates, bicarbonates, and alkali metal hydroxides. Among these, at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, potassium hydroxide, and sodium hydroxide is preferred, and at least one selected from the group consisting of ammonia and tetramethylammonium hydroxide is more preferred. The basic compounds may be used alone or in combination.

[0065] The basic compound may be a commercially available product or a synthetic product.

[0066] The content (concentration) of the basic compound in the raw solution is not particularly limited, but is preferably an amount such that the pH of the raw solution is 8.0 or higher, more preferably 8.5 or higher, and even more preferably 9.0 or higher. The content (concentration) of the basic compound in the raw solution is also not particularly limited, but is preferably an amount such that the pH of the raw solution is 13.0 or lower, more preferably 12.5 or lower, even more preferably 12.0 or lower, even more preferably 11.5 or lower, and particularly preferably 11.0 or lower. That is, it is preferable to contain the basic compound in the raw solution containing the raw water-soluble polymer and solvent so that the pH falls within the above-mentioned range. The preferred pH range of the raw solution obtained in the solution preparation step is the same as above. The preferred pH ranges of the raw solution used in the contact step and cation exchange step, which will be described later, are also the same as above.

[0067] The pH can be measured using LAQUA (registered trademark) manufactured by Horiba Ltd. or an equivalent product. The measurement method will be described in detail in the Examples.

[0068] Other ingredients The raw material solution may contain other components to the extent that the effects of the present invention are not impaired. The other components are not particularly limited, and examples thereof include components used in known polishing compositions, such as surfactants, chelating agents, organic acids, organic acid salts, inorganic acids, inorganic acid salts, preservatives, antifungal agents, oxidizing agents, and reducing agents. When hydroxyethyl cellulose is used as the raw material water-soluble polymer, other components include a solvent inhibitor to prevent overdissolution, an organic solvent, and the like. Examples of the anti-mold agent include, but are not limited to, monoaldehydes such as formaldehyde, acetaldehyde, butyraldehyde, isobutyraldehyde, and glycerin aldehyde; dialdehydes such as oxalic dialdehyde (ethanedial), malonic dialdehyde (propanedial), succinic dialdehyde (butanedial), glutaraldehyde, adipic aldehyde, octanedialdehyde, and phthalaldehyde; and trialdehydes such as triformylmethane and triformylethane; and compounds having a CHO group in the molecule.

[0069] (2) Contact treatment The water-soluble polymer contained in the polishing composition is prepared by (2) contacting a solution containing a raw water-soluble polymer and a solvent with a hydrophobic resin (contact treatment). The water-soluble polymer contained in the polishing composition is prepared by a contacting step including contacting a raw solution with a hydrophobic resin.

[0070] Hydrophobic resin In this specification, a hydrophobic resin refers to a resin made of a polymer containing a monomer A with an SP value of 13 or less. Here, SP value refers to the solubility parameter. In this specification, the SP value of a monomer constituting a hydrophobic resin refers to the value determined by the method described in RF Fedors: Polym. Eng. Sci., 14[2], 147-154 (1974). Note that ion exchange resins made of a polymer containing a monomer with an SP value of 13 or less and having ion exchange groups are not included in the hydrophobic resins in this specification. The ion exchange groups refer to cationic exchange groups such as sulfonic acid groups (-SO3H) and carboxylic acid groups (-COOH), and anionic exchange groups such as quaternary ammonium groups and primary, secondary, or tertiary amines.

[0071] The SP value of the monomer A constituting the hydrophobic resin is not particularly limited as long as it is 13 or less, but may be 12.5 or less, 12 or less, 11.5 or less, or 11 or less. In addition, the SP value of the monomer A constituting the hydrophobic resin is not particularly limited as long as it is 6 or more.

[0072] The monomer A constituting the hydrophobic resin is not particularly limited as long as it has an SP value of 13 or less, and examples thereof include ethylenically unsaturated monomers such as styrene and styrene derivatives each having an SP value of 10.55, ethylene each having an SP value of 8.56, and propylene each having an SP value of 8.02, acrylic acid esters, methacrylic acid esters, vinyl acetate, vinyl chloride, and nylon, monomers having an amide bond, oxymethylene, and units obtained by dehydration condensation of polyalcohols and polycarboxylic acids.

[0073] The hydrophobic resin is not particularly limited, but is preferably a (co)polymer containing a structural unit derived from at least one type of monomer A. Note that "structural unit derived from a monomer" does not only include a structural unit directly formed from that monomer, but also a structural unit that appears to be derived from that monomer by introducing a substituent after the polymerization reaction. In this specification, the term "(co)polymer" is a generic term that includes copolymers and homopolymers.

[0074] The styrene derivative is not particularly limited, and examples thereof include compounds in which hydrogen atoms in a styrene molecule are substituted with a substituent. Among these, preferred examples include styrene substituted with a hydrocarbon group and styrene substituted with a halogen group.

[0075] Examples of the hydrocarbon group include alkyl groups, alkenyl groups, and alkynyl groups, preferably alkyl groups having from 1 to 20 carbon atoms, alkenyl groups having from 2 to 20 carbon atoms, and alkynyl groups having from 2 to 20 carbon atoms. Among these, alkyl groups having from 1 to 20 carbon atoms and alkenyl groups having from 2 to 20 carbon atoms are preferred, alkyl groups having from 1 to 10 carbon atoms and alkenyl groups having from 2 to 10 carbon atoms are more preferred, alkyl groups having from 1 to 6 carbon atoms and alkenyl groups having from 2 to 6 carbon atoms are even more preferred, and an ethyl group and a vinyl group are particularly preferred.

[0076] Examples of halogen groups include a fluoro group (F-), a chloro group (Cl-), a bromo group (Br-), and an iodo group (I-). Among these, a bromo group is preferred. The position of the substituent is not particularly limited, but a compound in which a hydrogen atom on a benzene ring in a styrene molecule is substituted with a substituent is preferred. The number of substituents is not particularly limited, but is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1.

[0077] For these reasons, preferred examples of the monomer A constituting the hydrophobic resin include styrene, styrene substituted with an alkyl group, styrene substituted with a halogen group, divinylbenzene, divinylbenzene substituted with an alkyl group, and divinylbenzene substituted with a halogen group. Particularly preferred examples of the monomer A constituting the hydrophobic resin include styrene, ethylvinylbenzene, divinylbenzene, and brominated styrene, and include styrene, ethylvinylbenzene, divinylbenzene, orthobromostyrene, metabromostyrene, and parabromostyrene. The monomer A constituting the hydrophobic resin can be used alone or in combination of two or more.

[0078] The hydrophobic resin may further contain a constituent unit derived from a monomer B having an SP value of more than 13. The constituent unit derived from the monomer B is not particularly limited, and known ones can be used. Examples of such a monomer include vinyl alcohol and urethane monomers. The monomer B can be used alone or in combination of two or more.

[0079] The hydrophobic resin preferably contains a (co)polymer of multiple monomers including at least one monomer selected from the group consisting of styrene and styrene derivatives. The (co)polymer is more preferably a copolymer of multiple monomers including at least two monomers selected from the group consisting of styrene, divinylbenzene, ethylvinylbenzene, and brominated styrene (preferably at least one selected from the group consisting of orthobromostyrene, metabromostyrene, and parabromostyrene), even more preferably a copolymer of at least two monomers selected from the group consisting of styrene, divinylbenzene, ethylvinylbenzene, and brominated styrene (preferably at least one selected from the group consisting of orthobromostyrene, metabromostyrene, and parabromostyrene), and particularly preferably a copolymer of styrene and divinylbenzene, a copolymer of divinylbenzene and ethylvinylbenzene, or a copolymer of brominated styrene (preferably at least one selected from the group consisting of orthobromostyrene, metabromostyrene, and parabromostyrene) and divinylbenzene.

[0080] The hydrophobic resin preferably includes a resin containing a structural unit derived from at least one monomer selected from the group consisting of styrene and styrene derivatives. As the resin, a resin containing structural units derived from a plurality of monomers including at least two monomers selected from the group consisting of styrene, divinylbenzene, ethylvinylbenzene, and brominated styrene (preferably at least one selected from the group consisting of ortho-bromostyrene, meta-bromostyrene, and para-bromostyrene) is more preferred, a resin containing structural units derived from at least two monomers selected from the group consisting of styrene, divinylbenzene, ethylvinylbenzene, and brominated styrene (preferably at least one selected from the group consisting of ortho-bromostyrene, meta-bromostyrene, and para-bromostyrene) is even more preferred, and a resin containing structural units derived from styrene and divinylbenzene, a resin containing structural units derived from divinylbenzene and ethylvinylbenzene, or a resin containing structural units derived from brominated styrene (preferably at least one selected from the group consisting of ortho-bromostyrene, meta-bromostyrene, and para-bromostyrene) and divinylbenzene is particularly preferred.

[0081] The terminal of the hydrophobic resin is not particularly limited, but is preferably, for example, a hydrogen atom.

[0082] When the hydrophobic resin is a copolymer, the type of copolymer is not particularly limited, and may be any of a random copolymer, a block copolymer, and an alternating copolymer.

[0083] From the viewpoint of the effect of reducing defects on the surface of the object to be polished after polishing with the polishing composition, it is preferable that the hydrophobic resin has pores. The presence of pores in the hydrophobic resin can be confirmed by a gas adsorption method.

[0084] The frequency radius of the pores of the hydrophobic resin is not particularly limited, but is preferably 1 nm or more, more preferably 4 nm or more, and even more preferably 8 nm or more. Within this range, hydrophobic impurities are easily captured. Furthermore, the frequency radius of the pores of the hydrophobic resin is not particularly limited, but is preferably 100 nm or less, more preferably 30 nm or less, and even more preferably 15 nm or less. Within this range, hydrophobic impurities are easily captured. In a preferred embodiment, the frequency radius of the pores of the hydrophobic resin is 1 nm or more and 100 nm or less. The frequency radius of the pores of the hydrophobic resin can be measured by a gas adsorption method.

[0085] The hydrophobic resin is preferably in the form of particles. The shape of the particles is not particularly limited, and may be either spherical or non-spherical.

[0086] The particle size range of the hydrophobic resin is not particularly limited, but is preferably 100 μm or more, and may be 200 μm or more, or 300 μm or more. Within this range, hydrophobic impurities are more easily captured. The particle size range of the hydrophobic resin is not particularly limited, but is preferably 1000 μm or less, and may be 900 μm or less, or 800 μm or less. Within this range, hydrophobic impurities are more easily captured. In a preferred embodiment, the particle size of the hydrophobic resin is within the range of 100 μm or more and 1000 μm or less.

[0087] The particle size of the hydrophobic resin is not particularly limited, but it is preferable that 90% or more of the particles have a particle size of 250 μm or more (the total mass of particles with a particle size of 250 μm or more is 90% or more of the total mass of all particles). Within this range, the effect of reducing defects on the surface of the object to be polished is further improved.

[0088] The particle size of the hydrophobic resin can be determined by particle size measurement using a sieve.

[0089] The hydrophobic resin may be a commercially available product or a synthetic product, and may be used alone or in combination of two or more types.

[0090] ·Contact method In the contact treatment (2) above, the method (contact method) for contacting a raw solution containing a raw water-soluble polymer and a solvent with a hydrophobic resin is not particularly limited. Examples include (a) a method comprising passing the raw solution through a column containing a hydrophobic resin. Other examples include (b) a method comprising mixing the raw solution with a hydrophobic resin to obtain a mixture and stirring the mixture. In a preferred embodiment of the present invention, the contact method in the contact step includes at least one method selected from the group consisting of (a) passing the raw solution through a column containing a hydrophobic resin, and (b) mixing the raw solution with a hydrophobic resin to obtain a mixture and stirring the mixture. Among these, the method comprising (a) passing the raw solution through a column containing a hydrophobic resin is preferred.

[0091] In the above method (a), the method for passing the raw material solution through a column containing a hydrophobic resin is not particularly limited. For example, the raw material solution may be passed through a column containing a resin. At the start of passing the solution, the column containing the resin is preferably filled with water (preferably deionized water (DIW)). Although there are no particular limitations on the method for passing the solution, it is preferable to use an electric pump. Note that details of a preferred example of the procedure for the above method (a) are described in the Examples.

[0092] FIG. 1 is an explanatory diagram showing an example of a method for contacting a raw solution containing a raw water-soluble polymer and a solvent with a hydrophobic resin. In this method, the raw solution containing the raw water-soluble polymer and a solvent is passed through a column containing a hydrophobic resin. In FIG. 1, 1 represents the column, 2 represents the hydrophobic resin, D represents the direction in which the raw solution containing the raw water-soluble polymer and the solvent passes through, and A represents the cross-sectional area of the column. However, the contact method shown in FIG. 1 is merely an example, and the contact method of the present invention is not limited to this method.

[0093] The shape of the column is not particularly limited, but is preferably cylindrical. The cross-sectional area of the column is not particularly limited, but is preferably 1 cm 2 More than 10000cm 2 Less than 5cm is preferable 2 More than 5000cm 2 The following is more preferred. Within this range, the polishing composition has a high defect reduction effect, and productivity can be further improved. The cross-sectional area of the column refers to the cross-sectional area in a plane perpendicular to the direction of liquid flow. The column volume is not particularly limited, but is preferably 0.1 liters (l) or more, more preferably 0.5 liters or more, and even more preferably 1 liter or more. The column volume is also not particularly limited, but is preferably 100 liters or less, more preferably 75 liters or less, and even more preferably 50 liters or less. Within this range, the polishing composition has a high defect reduction effect, and productivity can be further improved.

[0094] The amount of hydrophobic resin added to the column is not particularly limited, but is preferably 50% by volume or more, more preferably 60% by volume or more, and even more preferably 70% by volume or more, based on the volume of the column. Within this range, the effect of reducing defects on the surface of the object to be polished after polishing with the polishing composition is further improved. The amount of hydrophobic resin added to the column is not particularly limited, but is preferably less than 100% by volume, more preferably 90% by volume or less, and even more preferably 80% by volume or less, based on the volume of the column. Within this range, productivity is further improved.

[0095] The flow rate of the raw solution is not particularly limited, but is preferably 10 ml / min or more, more preferably 100 ml / min or more, and even more preferably 250 ml / min or more. Within this range, productivity is further improved. The flow rate of the raw solution is not particularly limited, but is preferably 100,000 ml / min or less, more preferably 50,000 ml / min or less, and even more preferably 20,000 ml / min or less. Within this range, the effect of reducing defects on the surface of the object to be polished after polishing with the polishing composition is further improved. In one preferred embodiment of the present invention, in the above (a), the flow rate of the raw solution containing the raw water-soluble polymer and the solvent is 10 ml / min or more and 20,000 ml / min or less.

[0096] Unit cross-sectional area of the column (1cm 2 The flow rate of the raw solution per 1000 ml / min cm is not particularly limited, but is preferably 1 ml / min cm. 2 ) or more is preferable, and 2 ml / (min cm 2 ) or more is preferable, and 3 ml / (min cm 2 ) or more is more preferable. Within this range, productivity is further improved. 2 The flow rate of the raw solution per 1000 ml / min cm is not particularly limited, but is preferably 30 ml / min cm. 2 ) or less is preferable, and 20 ml / (min·cm 2 ) or less is preferable, and 10 ml / (min cm 2 ) or less is more preferable. Within this range, the effect of reducing defects on the surface of the object to be polished after polishing with the polishing composition is further improved. In a preferred embodiment of the present invention, in the above (a), the unit cross-sectional area (1 cm 2 The flow rate of the raw material solution containing the raw material water-soluble polymer and solvent per 1 ml / (min cm 2 ) or more 30ml / (min cm 2 ) within the following range.

[0097] The amount of the raw material solution passed through is not particularly limited as it varies depending on the amount of water-soluble polymer prepared, but is preferably 0.1 liters (l) or more, and more preferably 1 liter or more. The amount of the raw material solution passed through is not particularly limited, but is preferably 100,000 liters or less, and more preferably 50,000 liters or less.

[0098] The treatment temperature is not particularly limited, but is preferably 10° C. or higher and 30° C. or lower, and more preferably room temperature (20° C. or higher and 25° C. or lower).

[0099] (3) Cation exchange treatment The water-soluble polymer contained in the polishing composition may be, if necessary, subjected to cation exchange (cation exchange treatment) of the raw water-soluble polymer in the raw solution (3). That is, the water-soluble polymer may be prepared through a cation exchange process including cation exchange of the raw solution containing the raw water-soluble polymer and a solvent.

[0100] The cation exchange treatment is not particularly limited, but may be carried out between steps (1) and (2), after step (2), or both. In one embodiment of the present invention, the water-soluble polymer contained in the polishing composition is preferably prepared by the following steps: (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent; (2) contacting the raw solution with a hydrophobic resin; and (3) cation-exchanging the raw water-soluble polymer in the raw solution at least one selected from the group consisting of steps between steps (1) and (2) and after step (2). The cation exchange resin is not particularly limited, and known resins can be used. The cation exchange resin may be a commercially available product or a synthetic product. The ion exchange group is not particularly limited, but is preferably an acidic group, and more preferably a sulfonic acid group. The commercially available cation exchange resin may be used alone or in combination of two or more types.

[0101] The cation exchange method is not particularly limited, and known methods can be used. Among these, a method comprising passing a raw solution containing a raw water-soluble polymer and a solvent through a cation exchange resin is preferred. The cation exchange treatment may be carried out in the same manner as the above method (a), except for the resin used. The column shape, cross-sectional area, column volume, flow rate of the raw solution, and unit cross-sectional area (1 cm) of the column may also be used. 2 The ranges of the flow rate, the amount of the raw solution per column, and the treatment temperature are not particularly limited, but the preferred ranges for these are also the same as those for the above method (a). The range of the amount of the cation exchange resin added to the column is not particularly limited, but the preferred ranges for these are also the same as those for the amount of the hydrophobic resin added to the column in the above method (a).

[0102] After the cation exchange treatment, the pH of the raw solution may be adjusted. The pH adjustment is preferably performed using a basic compound. Examples of basic compounds include those described above for the raw solution, and preferred basic compounds include those described above for the raw solution. The pH of the raw solution after the cation exchange treatment is not particularly limited, but is preferably 8.0 or higher, more preferably 8.5 or higher, and even more preferably 9.0 or higher. The pH of the raw solution after the cation exchange treatment is not particularly limited, but is preferably 13.0 or lower, more preferably 12.5 or lower, even more preferably 12.0 or lower, even more preferably 11.5 or lower, and particularly preferably 11.0 or lower. The pH can be measured using LAQUA (registered trademark) manufactured by Horiba, Ltd., or an equivalent.

[0103] (4) Other processing The water-soluble polymer contained in the polishing composition may be further subjected to treatments other than the above (1) to (3) as necessary to prepare the water-soluble polymer used in the polishing composition.

[0104] In this way, the water-soluble polymer used in the polishing composition is prepared through the treatments (1) and (2). In addition to the treatments (1) and (2), the water-soluble polymer used in the polishing composition is preferably prepared by further undergoing the treatment (3) as needed. In addition to the treatments (1) and (2) or the treatments (1) to (3), the water-soluble polymer used in the polishing composition may be prepared by further undergoing a treatment other than the treatments (1) to (3) as needed.

[0105] The raw water-soluble polymer and the water-soluble polymer used in the polishing composition obtained by treating the raw water-soluble polymer are usually the same type. Therefore, examples of the types of water-soluble polymer used in the polishing composition are the same as those described above for the raw water-soluble polymer.

[0106] The preferred range of the weight-average molecular weight (Mw) of the water-soluble polymer obtained by the treatments (1) and (2) and, if necessary, further treatments other than these is the same as that of the raw water-soluble polymer. The method for measuring the weight-average molecular weight (Mw) of the obtained water-soluble polymer is also the same as that for the raw water-soluble polymer.

[0107] In the polishing composition, the water-soluble polymer may be used alone or in combination of two or more kinds.

[0108] The content (concentration) of water-soluble polymer in polishing composition is not particularly limited, but from the viewpoint of improving surface quality etc., it is preferably 0.0001 mass% or more, more preferably 0.0005 mass% or more, for example, more preferably 0.001 mass% or more, more preferably 0.002 mass% or more, and particularly preferably 0.005 mass% or more, relative to the total mass of polishing composition.In addition, the content (concentration) is not particularly limited, but from the viewpoint of improving polishing removal speed etc., such as reducing defects, it is preferably 1 mass% or less, more preferably 0.5 mass% or less, more preferably 0.2 mass% or less, even more preferably 0.05 mass% or less, and particularly preferably 0.01 mass% or less, relative to the total mass of polishing composition.

[0109] (abrasive grain) The polishing composition may or may not contain abrasive grains, but preferably contains abrasive grains.

[0110] When the polishing composition contains abrasive grains, the type of abrasive grains is not particularly limited, and examples thereof include inorganic particles, organic particles, and organic-inorganic composite particles. Among these, inorganic particles are preferred. In a polishing composition according to a preferred embodiment of the present invention, the abrasive grains contain inorganic particles. The inorganic particles are not particularly limited, and examples thereof 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. Among these, silica particles are more preferred, with colloidal silica particles and fumed silica particles being even more preferred, and colloidal silica particles being particularly preferred. The abrasive grains may be used alone or in combination of two or more types.

[0111] The average primary particle size of the abrasive grains is not particularly limited, but from the viewpoint of polishing efficiency, etc., it is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 15 nm or more. From the viewpoint of obtaining effects such as haze reduction and defect removal, the average primary particle size is preferably 15 nm or more, more preferably 20 nm or more, and can be, for example, more than 20 nm. Furthermore, from the viewpoint of suppressing local stress applied by the abrasive grains to the substrate surface, the average primary particle size of the abrasive grains is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 60 nm or less. The technology disclosed herein can also be preferably implemented in an embodiment using abrasive grains having an average primary particle size of 50 nm or less, typically less than 40 nm, and more preferably 35 nm or less, because a higher-quality surface is more likely to be obtained.

[0112] In this specification, the BET diameter is calculated from the specific surface area (BET value) measured by the BET method, as follows: BET diameter (nm) = 6000 / (true density (g / cm 3 )×BET value(m 2 The specific surface area can be measured using, for example, a surface area measuring device manufactured by Micromeritics, trade name "Flow Sorb II 2300".

[0113] The average secondary particle diameter of the abrasive grains is not particularly limited, but from the viewpoint of polishing efficiency, etc., 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 effects such as haze reduction and defect removal, the average secondary particle diameter is preferably 30 nm or more, more preferably 40 nm or more. Furthermore, from the viewpoint of suppressing local stress applied by the abrasive grains 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 can also be preferably implemented in an embodiment using abrasive grains having an average secondary particle diameter of 100 nm or less, for example, less than 80 nm (typically 45 nm or less), because a higher-quality surface is more likely to be obtained. By reducing the average secondary particle diameter of the abrasive grains, the stability of the polishing composition is improved.

[0114] The average secondary particle size of the abrasive grains can be measured by dynamic light scattering using, for example, a model "UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0115] The abrasive grains may be commercially available or synthetic.

[0116] The abrasive grains may be used alone or in combination of two or more kinds.

[0117] The content (concentration) of abrasive grains in the polishing composition is not particularly limited, but from the viewpoint of improving polishing removal speed, etc., it is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, more preferably 0.02 mass% or more, even more preferably 0.03 mass% or more, even more preferably 0.05 mass% or more, and particularly preferably 0.1 mass% or more, based on the total mass of the polishing composition.In addition, the content (concentration) of abrasive grains in the polishing composition is not particularly limited, but from the viewpoint of improving surface quality, such as reducing defects, it is preferably 25 mass% or less, more preferably 10 mass% or less, even more preferably 5 mass% or less, and particularly preferably 1 mass%.

[0118] (basic compounds) The polishing composition contains a basic compound, which is a compound that has the function of increasing the pH of water when added to water.

[0119] The type of basic compound is not particularly limited, and examples thereof include nitrogen-containing organic or inorganic basic compounds, hydroxides of alkali metals or Group 2 metals, various carbonates and bicarbonates, quaternary ammonium hydroxides or their salts, ammonia, amines, etc. The basic compound preferably includes at least one selected from the group consisting of nitrogen-containing organic or inorganic basic compounds, hydroxides of alkali metals or Group 2 metals, various carbonates and bicarbonates, quaternary ammonium hydroxides or their salts, ammonia, and amines. Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of Group 2 metal hydroxides include calcium hydroxide, strontium hydroxide, and barium hydroxide. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, and sodium carbonate. Specific examples of quaternary ammonium hydroxides or their salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, and tetrabutylammonium hydroxide. 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. From the viewpoint of reducing surface defects, the basic compound is preferably at least one selected from the group consisting of ammonia, quaternary ammonium hydroxide, salts of quaternary ammonium hydroxide, carbonates, hydrogen carbonates, and hydroxides of alkali metals. Among these, at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, potassium hydroxide, and sodium hydroxide is preferred, and at least one selected from the group consisting of ammonia and tetramethylammonium hydroxide is more preferred. The basic compounds may be used alone or in combination.

[0120] The basic compound may be a commercially available product or a synthetic product.

[0121] The content (concentration) of basic compound in polishing composition is not particularly limited, but from the viewpoint of improving polishing removal speed, etc., it is preferably 0.0001 mass% or more, more preferably 0.0005 mass% or more, more preferably 0.001 mass% or more, even more preferably 0.002 mass% or more, and particularly preferably 0.005 mass% or more, based on the total mass of polishing composition.In addition, the content (concentration) of basic compound in polishing composition is not particularly limited, but from the viewpoint of improving surface quality, such as reducing defects, it is preferably less than 15 mass%, more preferably less than 10 mass%, even more preferably less than 5 mass%, even more preferably less than 1.0 mass%, and particularly preferably less than 0.5 mass%.

[0122] (surfactant) The polishing composition may contain a surfactant. Anionic, cationic, nonionic, or amphoteric surfactants can be used. Among these, anionic or nonionic surfactants are preferred. Nonionic surfactants are more preferred from the viewpoints of low foaming and ease of pH adjustment. Examples of nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; and copolymers of multiple oxyalkylenes. Examples of polyoxyalkylene derivatives include polyoxyalkylene adducts. Examples of copolymers of multiple oxyalkylenes include diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers. Among these, polyoxyalkylene derivatives are preferred, and polyoxyethylene alkyl ethers are more preferred. The polyoxyethylene alkyl ether is not particularly limited, but includes 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, polyoxyethylene oleyl ether, etc. Among these, polyoxyethylene decyl ether is more preferred. The surfactants can be used alone or in combination of two or more.

[0123] The surfactant may be a commercially available product or a synthetic product.

[0124] The content (concentration) of surfactant in the polishing composition is not particularly limited, but is preferably 0.00001 mass% or more, more preferably 0.00005 mass% or more, more preferably 0.0001 mass% or more, even more preferably 0.0002 mass% or more, and particularly preferably 0.0005 mass% or more, based on the total mass of the polishing composition.Furthermore, the content (concentration) of surfactant in the polishing composition is preferably 1.5 mass% or less, more preferably 1 mass% or less, even more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, and particularly preferably 0.05 mass% or less, based on the total mass of the polishing composition.

[0125] (dispersion medium) The polishing composition may contain a dispersion medium. The dispersion medium preferably contains water. The content of water in the dispersion medium is not particularly limited, but is preferably 50% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass (water only) relative to the total mass of the dispersion medium. From the viewpoint of improving surface quality, such as reducing defects, the water preferably contains as few impurities as possible. For example, water having a total transition metal ion content of 100 ppb or less is preferred. Here, the purity of the water can be increased by, for example, removing impurity ions using an ion exchange resin, removing foreign matter using a filter, distillation, or other procedures. Specifically, the water preferably includes, for example, deionized water (DIW) (ion-exchanged water), pure water, ultrapure water, distilled water, etc.

[0126] The dispersion medium may be an organic solvent or a mixed solvent of water and an organic solvent, provided that it can improve the dispersibility or solubility of each component. The organic solvent is not particularly limited, and known organic solvents can be used. When a mixed solvent of water and an organic solvent is used, organic solvents that are miscible with water, such as acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, are preferably used. The organic solvent may be used alone or in combination of two or more.

[0127] (Other ingredients) The polishing composition may contain other components within the range that does not impair the effects of the present invention. The other components are not particularly limited, and examples thereof include components used in known polishing compositions, such as water-soluble polymers that have not been treated as disclosed herein, chelating agents, organic acids, organic acid salts, inorganic acids, inorganic acid salts, preservatives, antifungal agents, oxidizing agents, and reducing agents.

[0128] (pH) The pH of the polishing composition is not particularly limited, but is preferably greater than 7.0, more preferably 8.0 or more, even more preferably 8.5 or more, even more preferably 9.0 or more, particularly preferably 9.5 or more, and even more particularly preferably 10.0 or more.When the pH of the polishing composition increases, the polishing removal rate tends to improve.On the other hand, from the viewpoint of preventing the dissolution of abrasive grains and suppressing the deterioration of mechanical polishing action, the pH of the polishing composition is preferably 12.0 or less, more preferably 11.5 or less, even more preferably 11.0 or less, even more preferably 10.8 or less, and particularly preferably 10.5 or less.

[0129] The pH can be determined using a pH meter by performing three-point calibration using a standard buffer solution, placing a glass electrode in the composition to be measured, and measuring the value after stabilization for at least two minutes. Examples of pH meters that can be used include LAQUA (registered trademark) manufactured by Horiba, Ltd., or equivalents. Examples of standard buffer solutions that can be used include phthalate pH buffer solution (pH: 4.01 (25°C)), neutral phosphate pH buffer solution (pH: 6.86 (25°C), and carbonate pH buffer solution (pH: 10.01 (25°C)).

[0130] (Application) The polishing composition can be used to polish objects of various materials and shapes. The object to be polished is not particularly limited, but is preferably a substrate, more preferably a semiconductor substrate. The substrate material can be, for example, metals or semimetals such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, 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; and resin materials such as polyimide resin. The substrate may be made of a plurality of these materials.

[0131] The polishing composition can be particularly preferably used for polishing a surface made of silicon, typically for polishing a silicon wafer. 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. The polishing composition can be suitably used for polishing a substrate having a surface made of silicon.

[0132] The polishing composition can be preferably applied to a polishing step of, for example, a silicon wafer, etc. Before the polishing step with the polishing composition, the substrate may be subjected to a general treatment that can be applied to a substrate in a step upstream of the polishing step, such as lapping or etching.

[0133] The polishing composition can be preferably used, for example, in polishing an object to be polished (e.g., a silicon wafer) whose surface roughness has been adjusted to 0.01 nm to 100 nm by an upstream process. The surface roughness Ra of the object to be polished can be measured, for example, using a laser scanning surface roughness meter "TMS-3000WRC" manufactured by Schmitt Measurement System Inc. Use in final polishing (finish polishing) and polishing immediately before final polishing (polishing immediately before finish polishing) is effective, and use in final polishing is particularly preferred. Here, final polishing refers to the last polishing step in the manufacturing process of the object, i.e., a step in which no further polishing is performed after that step. The polishing composition disclosed herein may also be used in a polishing step upstream of final polishing. Here, the polishing step upstream of final polishing refers to a preliminary polishing step between the rough polishing step and the final polishing step. Typically, at least a first polishing step is included, and it may further include a second, third, etc. polishing step.

[0134] A polishing composition is typically supplied to an object to be polished in the form of a polishing liquid and used to polish the object. The polishing liquid can be prepared, for example, by diluting any of the polishing compositions disclosed herein. The dilution is typically with water. Alternatively, the polishing composition may be used as a polishing liquid as is. That is, the concept of a polishing composition in the technology disclosed herein encompasses both a polishing liquid (working slurry) that is supplied to an object to be polished and used to polish the object to be polished, and a concentrated liquid that is diluted and used as a polishing liquid, i.e., an undiluted polishing liquid. Another example of a polishing liquid containing a polishing composition is a polishing liquid obtained by adjusting the pH of a polishing composition.

[0135] (Concentrate) The polishing composition may be in a concentrated form before being supplied to the object to be polished. That is, from this, it can be said that another aspect of the present invention relates to a concentrated polishing liquid comprising the above-mentioned polishing composition. The polishing composition is in the form of a concentrated polishing liquid and can also be understood as a stock polishing liquid. A polishing composition in such a concentrated form is advantageous from the viewpoints of convenience and cost reduction during production, distribution, storage, etc. The concentration ratio is not particularly limited, and can be, for example, about 2 to 100 times in volume terms, and is usually about 5 to 50 times (e.g., about 10 to 40 times).

[0136] Such a concentrate can be diluted at a desired time to prepare a polishing liquid (working slurry), which can then be supplied to the object to be polished. The dilution can be carried out, for example, by adding water to the concentrate and mixing the mixture.

[0137] The content (concentration) of abrasive grains in the concentrated solution is not particularly limited, but can be, for example, 50% by mass or less, based on the total mass of the concentrated solution. From the viewpoint of the handleability of the concentrated solution, such as the dispersion stability of the abrasive grains and filterability, the content is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. Furthermore, the content (concentration) of abrasive grains is not particularly limited, but from the viewpoint of convenience and cost reduction during production, distribution, storage, etc., the content (concentration) of abrasive grains is preferably 0.5% 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 concentrated solution.

[0138] (Method of manufacturing polishing composition) The method for producing a polishing composition is not particularly limited as long as it includes mixing the components contained in the polishing composition. That is, the method for producing a polishing composition is not particularly limited as long as it includes mixing a basic compound with a water-soluble polymer that has been treated as disclosed herein. Therefore, another aspect of the present invention can be said to be a method for producing a polishing composition, which includes (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent, and (2) contacting the raw solution with a hydrophobic resin (contact treatment) to prepare a water-soluble polymer, and then mixing the water-soluble polymer solution with a basic compound. Furthermore, other components may be further added and mixed as necessary.

[0139] A method for producing a polishing composition includes (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent, (2) contacting the raw solution with a hydrophobic resin (contact treatment), and then mixing the obtained water-soluble polymer solution with a basic compound.A more preferred embodiment of the method for producing a polishing composition includes (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent, (2) contacting the raw solution with a hydrophobic resin (contact treatment), and then mixing the obtained water-soluble polymer solution with a basic compound and abrasive grains.By producing a polishing composition in this manner, it is possible to prevent abrasive grain aggregation, thereby improving polishing performance.

[0140] The order of addition of the basic compound and / or other components that may be added as needed is not particularly limited.When producing a polishing composition containing abrasive grains, the order of addition of the basic compound and / or other components that may be added as needed other than the abrasive grains may be before or after mixing the obtained water-soluble polymer solution with the abrasive grains.In addition, after adding the basic compound and / or other components that may be added as needed, a filtration step may be performed as needed.

[0141] The polishing composition may be a single-component type or a multi-component type such as a two-component type. For example, when producing a polishing composition containing abrasive grains, the polishing composition may be configured to prepare a polishing liquid by mixing a part A containing at least abrasive grains and a part B containing at least a part of the remaining components of the polishing composition, and mixing and diluting them at an appropriate timing as needed.

[0142] The means for mixing the components is not particularly limited. For example, the components constituting the polishing composition may be mixed using a well-known mixing device such as a blade stirrer, an ultrasonic disperser, or a 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. The mixing temperature is not particularly limited, but is generally preferably 10 to 40°C, and heating may be used to increase the dissolution rate. The mixing time is also not particularly limited.

[0143] As described above, the water-soluble polymer contained in the polishing composition is prepared by (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent, and (2) contacting the raw solution with a hydrophobic resin (contact treatment). Alternatively, the water-soluble polymer contained in the polishing composition may be prepared by cation-exchanging the raw water-soluble polymer in the raw solution (cation-exchange treatment). The cation-exchange treatment is not particularly limited, but is preferably carried out at least one selected from the group consisting of between (1) and (2) above and after (2) above.

[0144] That is, another aspect of the present invention can be said to relate to a method for producing a polishing composition, which includes (1) dissolving a raw water-soluble polymer in a solvent to obtain a raw solution, and (2) contacting the raw solution with a hydrophobic resin to prepare a water-soluble polymer, and then mixing the water-soluble polymer with a basic compound. This production method is also an example of the polishing composition described above. In this production method, it is preferable to further mix abrasive grains in addition to the water-soluble polymer and the basic compound.

[0145] One embodiment of a method for producing a polishing composition includes the steps of: (1) obtaining a raw solution containing a raw water-soluble polymer and a solvent; (2) contacting the raw solution with a hydrophobic resin; and (3) subjecting the raw water-soluble polymer in the raw solution to cation exchange at least one selected from the group consisting of between (1) and (2) and after (2), thereby preparing a water-soluble polymer, and mixing the water-soluble polymer with a basic compound. Preferably, the production method further includes mixing abrasive grains in addition to the water-soluble polymer and the basic compound.

[0146] In the method for producing a polishing composition, the details of the method for preparing the water-soluble polymer are as described above. The details of each component, physical properties, and characteristics of the polishing composition are also as described above. Preferred embodiments thereof are also as described above.

[0147] (polishing method) As described above, the polishing composition is preferably used for polishing an object to be polished. That is, another aspect of the present invention can also be said to relate to a polishing method for polishing an object to be polished using the polishing composition.

[0148] The polishing equipment and polishing conditions used in polishing will be explained below.As mentioned above, the concept of polishing composition includes both the polishing liquid (working slurry) that is supplied to a substrate and used to polish the substrate, and the concentrated liquid that is diluted and used as a polishing liquid, that is, the original solution of the polishing liquid.Another example of the polishing liquid that contains the polishing composition is the polishing liquid that is obtained by adjusting the pH of the polishing composition.

[0149] The polishing apparatus is not particularly limited, but for example, a general polishing apparatus can be used that is equipped with a holder for holding a substrate or the like having an object to be polished, a motor with an adjustable rotation speed, and a polishing platen to which a polishing pad (polishing cloth) can be attached. For example, a single-sided polishing apparatus or a double-sided polishing apparatus can be used. The commercially available polishing apparatus is not particularly limited, but an example of a single-sided polishing apparatus is a sheet-fed polishing machine, model "PNX 332B," manufactured by Okamoto Machine Tool Works, Ltd.

[0150] When polishing an object using a single-sided polishing machine, the object is held using a holder called a template, and a polishing platen with a polishing pad (polishing cloth) attached is pressed against one side of the object, and the polishing platen is rotated while a polishing liquid is supplied, thereby polishing one side of the object.When polishing an object using a double-sided polishing machine, the object is held using a holder called a carrier, and polishing plates with a polishing pad (polishing cloth) attached are pressed against both sides of the object from both sides, and both polishing plates are rotated while a polishing liquid is supplied, thereby polishing both sides of the object.

[0151] As the polishing pad, general nonwoven fabric type, polyurethane type, suede type, etc. can be used without any particular limitation. Polishing pads with grooves formed to allow the polishing liquid to accumulate can also be used. There are no particular limitations on commercially available polishing pads, but examples of nonwoven fabric types include "FP55" manufactured by Fujibo Ehime Co., Ltd., and examples of suede types include "POLYPAS27NX" manufactured by Fujibo Ehime Co., Ltd.

[0152] The preferred range of polishing conditions varies depending on the purpose of polishing at each polishing stage. Therefore, the polishing conditions are not particularly limited, and appropriate conditions can be adopted depending on the purpose of polishing at each polishing stage.

[0153] Polishing is preferably carried out by rotating a platen (polishing table), and more preferably by moving (e.g., rotating) the object to be polished and the platen (polishing table) relatively. The rotation speed of the platen (polishing table) and the rotation speed of the head (carrier, template) are not particularly limited, but are preferably set independently at 10 rpm (0.17 s -1 ) or more 100rpm(1.67s -1 ) or less, and more preferably 20 rpm (0.33 s -1 ) or more than 60 rpm (1 s -1 ) or less, and more preferably 25 rpm (0.42 s -1 ) or more than 55 rpm (0.92 s -1 ) or less. Within these ranges, the effect of reducing defects on the surface of the object to be polished is further improved, and production efficiency is further improved. Furthermore, the rotation speed of the platen (polishing table) and the rotation speed of the head (carrier, template) may be the same or different.

[0154] The object to be polished is usually pressed by a platen. The pressure (polishing load) at this time is not particularly limited, but is preferably 5 kPa or more and 30 kPa or less, more preferably 10 kPa or more and 25 kPa or less. Within these ranges, the effect of reducing defects on the surface of the object to be polished is further improved, and production efficiency is further improved.

[0155] The supply rate of the polishing liquid is not particularly limited, as it can be appropriately selected depending on the size of the polishing platen, but it is preferable that the supply rate be such that the entire object to be polished is covered. From the viewpoint of economic efficiency, the supply rate of the polishing liquid is more preferably 0.1 liters (l) / min or more and 5 liters / min or less, and even more preferably 0.2 liters / min or more and 2 liters / min or less. Within these ranges, the effect of reducing defects on the surface of the object to be polished is further improved, and production efficiency is further improved.

[0156] The method for supplying the polishing liquid is not particularly limited, and a method of continuously supplying the polishing liquid using a pump or the like (flowing liquid) may be employed.

[0157] There are no particular restrictions on the temperature at which the polishing liquid is maintained in the polishing apparatus, but from the viewpoint of the stability of the polishing rate and the effect of reducing defects on the surface of the object to be polished, it is preferably 15°C or higher and 40°C or lower, and more preferably 18°C or higher and 25°C or lower.

[0158] In addition, the polishing liquid may be recovered after being used to polish an object to be polished, and the composition may be adjusted by adding various components that may be contained in the polishing liquid as necessary, and then reused to polish an object to be polished.

[0159] The polishing time is not particularly limited, but is preferably 1 second to 600 seconds, more preferably 2 minutes to 8 minutes, and even more preferably 3 minutes to 5 minutes. Within these ranges, the effect of reducing defects on the surface of the object to be polished is further improved, and production efficiency is further improved. When polishing is performed multiple times, the polishing time refers to the time for each polishing.

[0160] The polishing composition according to the above embodiment is preferably used for final polishing (finish polishing) and polishing immediately before final polishing (polishing immediately before finish polishing). Furthermore, it is more preferable to perform final polishing (finish polishing) and polishing immediately before final polishing (polishing immediately before finish polishing) after polishing using a polishing composition other than the polishing composition according to the above embodiment. The polishing composition other than the polishing composition according to the above embodiment is not particularly limited, and examples thereof include polishing compositions containing colloidal silica and potassium hydroxide.

[0161] As mentioned above, the object to be polished is preferably a semiconductor substrate. That is, another aspect of the present invention can be said to relate to a method for manufacturing a semiconductor substrate, which includes polishing a semiconductor substrate to be polished using the polishing composition. The semiconductor substrate to be polished and the material and shape of the semiconductor substrate are the same as those described above for the use of the polishing composition. [Example]

[0162] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0163] <Preparation of water-soluble polymer> [Preparation of hydroxyethyl cellulose 1] (preparation process) As the raw hydroxyethyl cellulose (raw HEC), 11.66 parts by mass of hydroxyethyl cellulose with a weight-average molecular weight (Mw) of approximately 300,000 was added to 98.33 parts by mass of deionized water (DIW) as a solvent in a 4-liter (1) container and stirred. Then, 29% by mass of ammonia water was added, and the mixture was stirred and mixed at 25±5°C for 3 hours to obtain a raw solution. The ammonia water was added until the pH of the raw solution reached 10.0. The concentration of raw HEC in the raw solution was 1.66% by mass based on the total mass of the raw solution.

[0164] The pH of the raw material solution was measured using a pH meter by performing three-point calibration using a standard buffer solution, then placing a glass electrode in the composition to be measured and measuring the value after stabilization for at least two minutes. The pH meter used was a LAQUA (registered trademark) manufactured by Horiba, Ltd. The standard buffer solutions used were a phthalate pH buffer solution, pH: 4.01 (25°C), a neutral phosphate pH buffer solution, pH: 6.86 (25°C), and a carbonate pH buffer solution, pH: 10.01 (25°C).

[0165] The weight-average molecular weight of the raw HEC was evaluated as follows. The raw HEC was diluted with deionized water (DIW) to a concentration of 0.1% by mass to obtain a sample for GPC measurement. The weight-average molecular weight (Mw) of the raw HEC contained in this sample was measured using gel permeation chromatography (GPC) under the following measurement conditions: [GPC measurement conditions] Measurement equipment: Tosoh Corporation HLC-8320 GPC Column: TSKgel GMPWXL manufactured by Tosoh Corporation Molecular weight marker: Agilent Technologies polyethylene oxide-polyethylene glycol Eluent: 0.1M NaNO3 Flow rate: 1.0ml / min.

[0166] (cation exchange process) The solution obtained in the preparation step was passed through a column packed with a strongly acidic cation exchange resin (exchange group: sulfonic acid group) to perform cation exchange.

[0167] (contact process) The solution obtained in the cation exchange step was brought into contact with hydrophobic resin 1 (a resin containing structural units derived from styrene and structural units derived from divinylbenzene) according to the following procedure.

[0168] <Procedure> Step 1. Place hydrophobic resin in the column.

[0169] Step 2: After step 1 above, fill the column with deionized water (DIW).

[0170] Step 3: After step 2 above, use an electric pump to pass the solution to be treated through the column.

[0171] The solution to be treated in step 3 above is the solution obtained in the cation exchange process. The concentration of raw HEC in the solution obtained in the cation exchange process was 1.1% by mass. The reason for the difference in the concentration of raw HEC in the solution obtained in the cation exchange process and the solution obtained in the preparation process is thought to be because the concentration of raw HEC in the solution decreased when passed through the cation exchange resin. The concentration of raw HEC was calculated from the dry mass. Here, the dry mass was determined by placing the solution obtained in the cation exchange process in a petri dish, measuring its weight (mass), placing it in an air bath at 100°C to evaporate the water, and then measuring the weight (mass) of the petri dish (containing the powder).

[0172] The contact step was carried out at room temperature in the range of 10°C or higher and 30°C or lower.

[0173] In addition, in the above procedure 1, about 700 ml of hydrophobic resin was placed in a cylindrical column having a diameter of 7.8 cm and a volume of 1 liter (l).

[0174] In step 3 above, the flow rate of the solution to be treated is 300 ml / min, and the flow rate per unit cross-sectional area of the column is 6.3 ml / (min cm 2 ) The solution to be treated was passed through in an amount of 4 liters (l).

[0175] In this way, a solution containing hydroxyethyl cellulose 1 was obtained.

[0176] [Preparation of hydroxyethyl cellulose 2] A solution containing hydroxyethyl cellulose 2 was obtained in the same manner as in the preparation of hydroxyethyl cellulose 1 above, except that the hydrophobic resin 1 used in the contact step was changed to hydrophobic resin 2 (a resin containing a structural unit derived from divinylbenzene and a structural unit derived from ethylvinylbenzene).

[0177] [Preparation of hydroxyethyl cellulose 3] A solution containing hydroxyethyl cellulose 3 was obtained in the same manner as in the preparation of hydroxyethyl cellulose 1 above, except that the hydrophobic resin 1 used in the contact step was changed to hydrophobic resin 3 (a resin containing a structural unit derived from brominated styrene and a structural unit derived from divinylbenzene).

[0178] [Preparation of Hydroxyethyl Cellulose 4] A solution containing hydroxyethyl cellulose 4 was obtained in the same manner as in the preparation of hydroxyethyl cellulose 1 above, except that the hydrophobic resin 1 used in the contact step was changed to hydrophobic resin 4 (a resin containing a styrene-derived structural unit and a divinylbenzene-derived structural unit).

[0179] [Preparation of Hydroxyethyl Cellulose 5] A solution containing hydroxyethyl cellulose 5 was obtained in the same manner as in the preparation of hydroxyethyl cellulose 1 above, except that the contact step was not carried out.

[0180] [Physical properties of hydrophobic resins used to prepare each hydroxyethyl cellulose] The physical properties of the hydrophobic resins used to prepare each hydroxyethyl cellulose are shown in Table 1 below.

[0181] The particle size of the hydrophobic resin and the proportion of particles of each particle size were confirmed by particle size measurement using a sieve. The hydrophobic resin was confirmed by gas adsorption, and it was confirmed that the hydrophobic resins used to prepare hydroxyethyl celluloses 1 to 4 had pores. The most frequent pore radius was also evaluated by gas adsorption.

[0182] [Table 1]

[0183] <Preparation of Polishing Composition> (Examples 1 to 4, Comparative Example 1) Each polishing composition concentrate was prepared by mixing the above-prepared solutions containing hydroxyethyl cellulose, abrasive grains, a basic compound, surfactant, and deionized water (DIW). Colloidal silica with an average primary particle size of 35 nm was used as the abrasive grains, ammonia was used as the basic compound, and polyoxyethylene decyl ether was used as the surfactant. In each polishing composition concentrate, the hydroxyethyl cellulose concentration was 0.18% by mass, the colloidal silica concentration was 2.5% by mass, the ammonia concentration was 0.1% by mass, and the polyoxyethylene decyl ether concentration was 0.01% by mass.

[0184] Each polishing composition was obtained by diluting the resulting concentrate with deionized water (DIW) by a volume ratio of 20 times. In each polishing composition, the hydroxyethyl cellulose concentration was 0.009% by mass, the colloidal silica concentration was 0.125% by mass, the ammonia concentration was 0.005% by mass, and the polyoxyethylene decyl ether concentration was 0.0005% by mass.

[0185] [Silicon wafer polishing] 12-inch diameter silicon wafer (conductivity type: P type, crystal orientation: <100> A polishing solution containing abrasive grains, a basic compound, and deionized water (DIW) was prepared and used for preliminary polishing under the following conditions. The polishing solution used for preliminary polishing was obtained by diluting a concentrated solution of the composition prepared by mixing abrasive grains, a basic compound, and deionized water (DIW) to a volume ratio of 20 times with deionized water (DIW). Colloidal silica with an average primary particle size of 42 nm was used as the abrasive grains, and potassium hydroxide was used as the basic compound. In the polishing solution used for preliminary polishing, the colloidal silica concentration was 1% by mass, and the potassium hydroxide concentration was 0.068% by mass.

[0186] [Preliminary polishing conditions] Polishing equipment: Okamoto Machine Tool Works, Ltd., sheet-fed polishing machine, model "PNX 332B" Polishing load: 12kPa Plate rotation speed: 50 rpm Head rotation speed: 52 rpm Polishing pad: Fujibo Ehime Co., Ltd., product name "FP55" Polishing time: 4 minutes Polishing solution temperature: 20℃ Polishing liquid supply rate: 2.0 liters / minute (flow-through use).

[0187] The polishing composition prepared above was used as a polishing liquid to polish the silicon wafer obtained through the above preliminary polishing under the following polishing conditions 1, and then polished under the following polishing conditions 2.

[0188] [Polishing conditions 1] Polishing equipment: Okamoto Machine Tool Works, Ltd., sheet-fed polishing machine, model "PNX 332B" Polishing load: 16kPa Plate rotation speed: 50 rpm Head rotation speed: 52 rpm Polishing pad: Fujibo Ehime Co., Ltd., product name "POLYPAS (registered trademark) 27NX" Polishing time: 4 minutes Polishing solution temperature: 20℃ Polishing liquid supply rate: 1.5 liters / minute (flow-through use).

[0189] [Polishing conditions 2] Polishing equipment: Okamoto Machine Tool Works, Ltd., sheet-fed polishing machine, model "PNX 332B" Polishing load: 20kPa Plate rotation speed: 50 rpm Head rotation speed: 52 rpm Polishing pad: Fujibo Ehime Co., Ltd., product name "POLYPAS (registered trademark) 27NX" Polishing time: 4 minutes Polishing solution temperature: 20℃ Polishing liquid supply rate: 1.5 liters / minute (flow-through use).

[0190] The preliminary polishing, the polishing under polishing condition 1, and the polishing under polishing condition 2 were each performed on a different polishing platen.

[0191] [LPD-N number measurement] The number of LPD-N (Light Point Defect Non-cleanable) defects present on the surface (polished surface) of the silicon wafers obtained by the above polishing was counted using a wafer inspection system manufactured by KLA-Tencor Corporation, product name "SURFSCAN SP2," in the DCO mode of the system.

[0192] The evaluation results of Examples 1 to 4 and Comparative Example 1 are shown in Table 2 below. The LPD-N values in Table 2 are shown as relative values when the LPD-N value of Comparative Example 1 is set to 100%.

[0193] [Table 2]

[0194] The results in Tables 1 and 2 above confirm that polishing with hydroxyethyl cellulose, which has been prepared by the following steps: (1) dissolving raw HEC in water to obtain a raw solution; and (2) bringing the raw solution into contact with a hydrophobic resin, significantly reduces defects on the surface of the object to be polished. [Explanation of symbols]

[0195] 1 column 2. Hydrophobic resin D. Raw material solution containing raw material water-soluble polymer and solvent A Column cross-sectional area

Claims

1. (1) obtaining a raw material solution containing a raw material water-soluble polymer and a solvent; (2) contacting the raw material solution with a hydrophobic resin having micropores; preparing a water-soluble polymer through mixing the water-soluble polymer with a basic compound; Including, A method for producing a polishing composition.

2. 2. The method for producing a polishing composition according to claim 1, wherein the preparation of the water-soluble polymer further comprises cation-exchanging the raw water-soluble polymer in the raw solution at least one selected from the group consisting of between (1) and (2) and after (2).

3. 3. The method for producing a polishing composition according to claim 1, wherein in (1), the raw water-soluble polymer is added in an amount of 0.1 mass % to 5 mass % relative to the total mass of the raw solution.

4. In the above (2), the method of bringing the raw material solution into contact with the hydrophobic resin comprises: (a) passing the raw material solution through a column containing a hydrophobic resin; and (b) mixing the raw material solution with the hydrophobic resin to obtain a mixed solution, and stirring the mixed solution; The method for producing a polishing composition according to any one of claims 1 to 3, which comprises at least one selected from the group consisting of:

5. 5. The method for producing a polishing composition according to claim 4, wherein in (a), the flow rate of the raw material solution is set to 10 ml / min or more and 20,000 ml / min or less.

6. In the above (a), the unit cross-sectional area (1 cm ２ The flow rate of the raw material solution per ２ ) or more 30ml / (min・cm ２ 6. The method for producing a polishing composition according to claim 5, wherein the average particle size is within the range of 0.1 to 1.0 μm.

7. The method for producing a polishing composition according to any one of claims 1 to 6, wherein the hydrophobic resin comprises a resin containing a structural unit derived from at least one monomer selected from the group consisting of styrene and styrene derivatives.

8. The method for producing a polishing composition according to any one of claims 1 to 7, wherein the most frequent radius of the pores is within a range of 1 nm or more and 100 nm or less.

9. The method for producing a polishing composition according to any one of claims 1 to 8, wherein the water-soluble polymer includes a cellulose derivative.

10. A method for producing a polishing composition described in any one of claims 1 to 9, further comprising mixing abrasive grains.

11. A method for producing a polishing composition described in any one of claims 1 to 10, wherein the polishing composition is a concentrated polishing liquid.

12. A polishing method comprising producing a polishing composition by the production method according to any one of claims 1 to 11, and polishing an object to be polished with the polishing composition.

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