Polishing composition

Abstract

To provide a novel polishing composition.SOLUTION: A polishing composition contains a water-soluble polymer comprising at least a vinyl alcohol resin that includes a side chain group having 3 or more carbons.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel polishing composition and the like. [Background technology]

[0002] The surface of a silicon wafer used as a component of a semiconductor device is generally finished to a high-quality mirror surface through a lapping process (rough polishing process) and a polishing process (precision polishing process). The polishing process typically includes a primary polishing process (primary polishing process) and a final polishing process (final polishing process).

[0003] In such a polishing step, a polishing composition is used. Polishing compositions containing water-soluble polymers are known. For example, Patent Document 1 describes a polishing composition containing hydroxyethyl cellulose and / or polyvinyl alcohol and a block polyether. Furthermore, Patent Document 2 discloses a semiconductor wetting agent containing a water-soluble polymer (hydroxyethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, etc.) having a specific viscosity.

[0004] Furthermore, in recent years, there has been an increasing demand for higher quality surfaces for semiconductor substrates such as silicon wafers and other substrates. Specifically, there is a demand for reducing minute defects on the surface (for example, surface defects called LPD (Light Point Defects)) and roughness. It is known that surface defects can be detected as LLS (Localized Light Scatters) defects by light scattering. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-85858 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-34509 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a novel polishing composition.

[0007] Another object of the present invention is to provide a polishing composition that can reduce the number of microdefects on the surface after polishing (particularly polishing of semiconductor substrates such as silicon wafers).

[0008] Another object of the present invention is to provide a polishing composition that leaves the surface after polishing with little haze.

[0009] Another object of the present invention is to provide a polishing composition which leaves a polished surface with small AFM roughness (roughness measured by AFM).

[0010] A further object of the present invention is to provide a method for producing a polished object using such a polishing composition. [Means for solving the problem]

[0011] The inventors have focused on defects of a smaller size than conventionally observed on the polished surface of a substrate such as a semiconductor substrate, and have found that when the surface of a semiconductor substrate is polished using a polishing composition containing a water-soluble polymer, depending on the type of water-soluble polymer, the number of micro-defects on the polished surface of the semiconductor substrate may increase.

[0012] As a result of extensive research to solve the above problems, the inventors have discovered that the number of microdefects (particularly LLS defects of 26 nm or more or 19 nm or more) on the polished surface of a semiconductor substrate can be reduced by using a polishing composition containing a specific water-soluble polymer.

[0013] The present inventors have found that by using such a polishing composition, it is possible to reduce haze and AFM roughness on the polished surface of a semiconductor substrate.

[0014] That is, the present invention relates to the following inventions. [1] A polishing composition containing a water-soluble polymer, wherein the water-soluble polymer contains at least a vinyl alcohol resin (A) having a side chain group having 3 or more carbon atoms. [2] A polishing composition containing a water-soluble polymer, wherein the water-soluble polymer contains at least one vinyl alcohol-based resin (B) selected from a vinyl alcohol-based resin (B1) having a saponification degree of more than 90 mol% and a 4% aqueous solution viscosity at 20°C of 300 mPa·s or less, and a vinyl alcohol-based resin (B2) having a saponification degree of 90 mol% or less. [3] The side chain group is C 7-30 Fatty acid vinyl ester derived group, C 3-30 The polishing composition according to [1] contains at least one selected from a group derived from an alkyl vinyl ether, a group derived from an aromatic carboxylic acid vinyl ester, a group derived from diacetone (meth)acrylamide, an acetoacetyl group, and an epoxy ring-opened product of a group derived from an epoxy group-containing vinyl monomer. [4] The polishing composition according to [1], wherein the side chain group comprises at least one selected from a group derived from a fatty acid vinyl ester having 3 or more carbon atoms, a group derived from an aromatic carboxylic acid vinyl ester, a group derived from diacetone (meth)acrylamide, and a polyoxyethylene group. [5] The side chain group is C 3-30 The polishing composition according to any one of [1] and [3], which contains at least one selected from a group derived from an alkyl vinyl ether and a group derived from diacetone (meth)acrylamide. [6] The polishing composition according to any one of [1] and [3] to [5], wherein the side chain group contains at least a group derived from diacetone (meth)acrylamide. [7] The polishing composition according to [1], wherein the vinyl alcohol resin (A) has a side chain group having 3 or more carbon atoms that contains a group derived from an alkyl vinyl ether having 4 or more carbon atoms, a 4% aqueous solution viscosity at 20°C of 100 mPa·s or more, and a number average molecular weight of 10,000 or more. [8] The polishing composition according to any one of [1] and [3] to [7], wherein the proportion of side chain groups is 0.05 mol % or more in terms of polymerization components (monomers). [9] The polishing composition according to [2], wherein the water-soluble polymer comprises a vinyl alcohol resin (B1).

[10] The polishing composition according to [2], wherein the vinyl alcohol resin (B) consists essentially of vinyl alcohol units and vinyl ester units.

[11] The polishing composition according to any one of [1] and [3] to [8], wherein the vinyl alcohol resin (A) has a degree of saponification of 80 to 99.9 mol % and a viscosity of a 4% aqueous solution at 20°C of 1 to 300 mPa·s.

[12] The polishing composition according to any one of [1] to

[11] , further comprising abrasive grains.

[13] The polishing composition according to any one of [1] to

[12] , further comprising a pH adjuster.

[14] The polishing composition according to any one of [1] to

[13] , further comprising an abrasive grain and a pH adjuster, wherein the abrasive grain contains silica and the pH adjuster contains a basic compound.

[15] [2] The polishing composition according to [2], wherein the water-soluble polymer contains a vinyl alcohol-based resin (B2) and the abrasive grains contain silica.

[16] The polishing composition according to any one of [1] to

[15] , further comprising a surfactant.

[17] The polishing composition according to any one of [1] to

[16] , further comprising a surfactant, wherein the surfactant comprises at least one selected from a copolymer having an oxyethylene-oxypropylene structure and a polyoxyethylene alkyl ether.

[18] The polishing composition according to any one of [1] to

[17] , further comprising a surfactant, wherein the ratio of the water-soluble polymer to the surfactant is 1:0.01 to 1:200 by mass.

[19] The polishing composition according to any one of [1] to

[18] , further comprising a solvent containing at least water, and the concentration of the water-soluble polymer is 1 ppm or more.

[20] The polishing composition according to any one of [1] to

[19] , further comprising a solvent containing at least water, and having a solid content concentration of 0.01 mass % or more. [twenty one] A polishing composition containing a water-soluble polymer, wherein the polished surface of an object to be polished after polishing and cleaning the object satisfies the following condition (A): (A) The number of LLS defects of 26 nm or more is 700 or less per 300 mm diameter. [twenty two] A polishing composition containing a water-soluble polymer, wherein the polished surface of an object to be polished after polishing and cleaning the object satisfies the following condition (B): (B) The number of LLS defects of 19 nm or more is 850 or less per 300 mm diameter. [twenty three] A method for producing a polished object, comprising a step of polishing a surface of an object to be polished with the polishing composition according to any one of [1] to

[22] . [twenty four]

[23] A method for producing a polished object according to

[23] , comprising a dilution step of diluting the polishing composition with a solvent containing at least water, and polishing in the polishing step with the diluted solution obtained in the dilution step. [twenty five] The method for producing an abrasive according to

[23] or

[24] , which produces an abrasive whose surface satisfies the following condition (A): (A) The number of LLS defects of 26 nm or more is 700 or less per 300 mm diameter.

[26] A polished object whose surface satisfies the following condition (A). (A) The number of LLS defects of 26 nm or more is 700 or less per 300 mm diameter.

[27] A method for reducing the number of LLS defects on a polished surface, comprising a step of polishing the surface of an object to be polished with the polishing composition according to any one of [1] to

[22] . [Effects of the Invention]

[0015] According to the present invention, a novel polishing composition can be provided. Such a composition can reduce the number of microdefects (particularly LLS defects of 26 nm or more or 19 nm or more) on the surface after polishing (particularly polishing of semiconductor substrates such as silicon wafers), thereby enabling the production of polished products with high-quality surfaces.

[0016] Furthermore, such a composition can reduce the haze on the surface after polishing, making it possible to obtain a polished product having a high-quality surface.

[0017] Furthermore, such a composition can reduce the AFM roughness (particularly long wavelength roughness) of the surface after polishing, allowing for efficient focusing during exposure in the production of semiconductor devices.

[0018] Furthermore, such a composition allows for efficient formation of semiconductor devices and the like.

[0019] The present invention also provides a method for producing a polished object using the above-mentioned composition. DETAILED DESCRIPTION OF THE INVENTION

[0020] (composition) The composition of the present invention generally contains a specific water-soluble polymer, which will be described later. The composition of the present invention can be used particularly for polishing.

[0021] (Water-soluble polymer) In the composition, the water-soluble polymer may contain a vinyl alcohol resin (A) having a side chain group with 3 or more carbon atoms.

[0022] (Vinyl alcohol resin (A)) Vinyl alcohol resins are usually polyvinyl alcohol resins (also called PVA resins, PVA, etc.), which are saponified vinyl ester polymers (polymers containing at least vinyl ester as a polymerization component).

[0023] The vinyl ester (vinyl ester monomer) is not particularly limited, but examples thereof include vinyl esters of fatty acids [e.g., C vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatate, and vinyl monochloroacetate]. 1-30 Fatty acid vinyl esters (e.g., C 1-16 alkanoic acid vinyl esters), etc.], aromatic carboxylic acid vinyl esters [e.g., arene carboxylic acid vinyl esters such as vinyl benzoate (e.g., C 7-12 arenecarboxylic acid-vinyl esters), etc.

[0024] The vinyl esters may be used alone or in combination of two or more.

[0025] The vinyl esters include at least fatty acid vinyl esters (e.g., C , such as vinyl formate, vinyl acetate, vinyl propionate, and vinyl butyrate). 1-10 It is preferable that the vinyl ester of ...

[0026] The vinyl ester polymer may contain units derived from other monomers (monomers copolymerizable with vinyl esters) as needed (or may be modified with other monomers).

[0027] The other monomers are not particularly limited, but examples thereof include alkyl vinyl ethers (e.g., C 10 alkyl vinyl ether such as hexadecyl vinyl ether, etc.) 1-30Alkyl vinyl ether, preferably C 1-16alkyl vinyl ether), epoxy group-containing vinyl monomers {for example, vinyl glycidyl ethers (for example, allyl glycidyl ether, (meth)acryl glycidyl ether, 4-(meth)acrylamidophenyl glycidyl ether, 3-(meth)acrylamidophenyl glycidyl ether, N-glycidoxymethyl(meth)acrylamide, N-glycidoxyethyl(meth)acrylamide, N-glycidoxypropyl(meth)acrylamide, N-glycidoxybutyl(meth)acrylamide, 4-(meth)acrylamidomethyl-2,5-dimethyl-phenyl glycidyl ether), epoxy group-containing α-olefins (for example, 1,2-epoxy-5-hexene, 1,2-epoxy-7-octene, 1,2-epoxy-9-decene, 8-hydroxy-6,7-epoxy-1-octene, 8-acetoxy-6,7-epoxy-1-octene), N-(2,3-epoxy)propyl(meth)acrylamide, (meth)acrylamidopropyldimethyl(2,3-epoxy)propylammonium chloride, glycidyl (meth)acrylate, etc.}, α-olefins (e.g., ethylene, propylene, etc.), (meth)acrylic acid esters [e.g., (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, diacetone (meth)acrylate], unsaturated amides [e.g., (meth)acrylamide, diacetone (meth)acrylamide, N-methylolacrylamide, etc.], unsaturated acids {e.g., unsaturated acids [e.g., (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, etc.], unsaturated acid esters [unsaturated acid esters other than (meth)acrylic acid, esters, for example, alkyl (methyl, ethyl, propyl, etc.) esters, unsaturated acid anhydrides (maleic anhydride, etc.), salts of unsaturated acids [for example, alkali metal salts (for example, sodium salts, potassium salts, etc.), ammonium salts, etc.], glycidyl group-containing monomers [for example, allyl glycidyl ether, glycidyl (meth)acrylate, etc.], sulfonic acid group-containing monomers (for example, 2-acrylamido-2-methylpropanesulfonic acid, its salts, etc.), phosphate group-containing monomers [for example, acid phosphooxyethyl (meth)acrylate, acid phosphooxypropyl (meth)acrylate, etc.], allyl alcohol, diacetone (meth)acrylamide, etc., but are not particularly limited to these.

[0028] The other monomers may be used alone or in combination of two or more.

[0029] The units derived from vinyl esters or units derived from other monomers may be modified to the extent that the effects of the present invention are not impaired.

[0030] The vinyl ester-derived units may be modified, for example, by acetalization, etherification, acetoacetylation, cationization, or polyoxyalkylene modification.

[0031] The modification of units derived from other monomers may be, for example, a ring-opening reaction of an epoxy group (for example, a reaction of an epoxy group with a thiol).

[0032] The modification method is not particularly limited, but examples of methods for acetoacetylating vinyl ester-derived units include a method of reacting a vinyl alcohol resin with diketene. The method for reacting a vinyl alcohol resin with diketene is not particularly limited, and examples thereof include a method of directly reacting a vinyl alcohol resin with gaseous or liquid diketene, a method of preliminarily adsorbing an organic acid onto a vinyl alcohol resin and then spraying gaseous or liquid diketene onto the vinyl alcohol resin in an inert gas atmosphere to cause the reaction, and a method of spraying a mixture of an organic acid and liquid diketene onto a vinyl alcohol resin to cause the reaction.

[0033] Examples of the ring-opening reaction of the epoxy group in the unit derived from another monomer include a method of reacting a unit derived from an epoxy group-containing vinyl monomer with a thiol (such as a thiol having an amino group).

[0034] The vinyl alcohol resin (A) may have at least a side chain group having 3 or more carbon atoms [for example, 3 to 30, 4 to 30, 5 to 30, 6 to 30, 7 or more (for example, 7 to 30)]. The side chain group having 3 or more carbon atoms may have one or more heteroatoms (e.g., nitrogen atom, oxygen atom, sulfur atom, etc.). The heteroatom may be present between carbon atoms in the side chain group having 3 or more carbon atoms. Furthermore, the side chain group having 3 or more carbon atoms may have a substituent (for example, an amino group).

[0035] The vinyl alcohol resin (A) may contain one or more types of side chain groups having 3 or more carbon atoms.

[0036] The side chain group having 3 or more carbon atoms may be contained in a monomer that is a polymerization component of the vinyl ester polymer (i.e., it may be a group derived from a monomer of the vinyl ester polymer), or may be introduced by partially modifying the vinyl ester polymer or a saponified vinyl ester polymer.

[0037] Examples of the side chain group having 3 or more carbon atoms include an alkyl group (e.g., C 3-30 Alkyl groups, preferably C 3-20 Alkyl groups, more preferably C 6-20 alkyl groups), aryl groups (e.g., C 6-30 Aryl groups, preferably C 6-20 an aryl group, more preferably C 11-20 aryl group), a group represented by the following formula (1), a polyoxyalkylene group (e.g., a polyoxy C group such as a polyoxyethylene group or a polyoxypropylene group), 2-6 alkylene group), a group having an acetoacetyl group, or the like, or an epoxy ring-opened product of a group derived from an epoxy group-containing vinyl monomer (for example, the epoxy group-containing vinyl monomers exemplified above).

[0038] [ka]

[0039] These groups may be bonded directly to the main chain of the vinyl alcohol resin (A) or may be bonded to the main chain via a linking group (for example, an ether bond, an ester bond, an amide bond, a urethane bond, etc.).

[0040] Specific examples of the group having an alkyl group include C 3-30 Fatty acid vinyl esters (e.g., vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatate, etc.) 3-30 Alkanoic acid vinyl esters, preferably C 7-30 Alkanoic acid vinyl esters, more preferably C 7-20 Alkanoic acid-vinyl ester) derived group, C 3-30Alkyl vinyl ethers [e.g., C such as hexadecyl vinyl ether] 7-30 Alkyl vinyl ether, preferably C 7-20 Alkyl vinyl ethers (e.g., C 11-20 Alkyl vinyl ether, C 13-20 alkyl vinyl ether, etc.)] derived from C 3-30 Alkyl groups (e.g., C 7-30 Alkyl group, C 11-30 Examples include urethane alkyl groups having alkyl groups.

[0041] Specific examples of the group having an aryl group include aromatic vinyl carboxylic acid esters [for example, vinyl arene carboxylates such as vinyl benzoate (for example, C 7-12 arenecarboxylic acid-vinyl ester)].

[0042] Specific examples of groups having a group represented by the above formula (1) include groups derived from diacetone (meth)acrylamide and groups derived from diacetone (meth)acrylate.

[0043] Examples of epoxy ring-opened products of groups derived from epoxy group-containing vinyl monomers include those that have undergone a ring-opening reaction of the epoxy group in a group derived from an epoxy group-containing vinyl monomer (for example, a reaction of an epoxy group with a thiol). The method for the ring-opening reaction of the epoxy group is not particularly limited, and examples thereof include a method of reacting a unit derived from an epoxy group-containing vinyl monomer with a thiol [e.g., a thiol having an amino group (e.g., a thiol described in Japanese Patent No. 3647630)] (e.g., the method described in Japanese Patent No. 3647630).

[0044] The side chain group having 3 or more carbon atoms is particularly 7-30 Fatty acid vinyl ester derived group, C 3-30The alkyl vinyl ether-derived group, the aromatic carboxylic acid vinyl ester-derived group, the diacetone (meth)acrylamide-derived group, the acetoacetyl group, and the epoxy ring-opened product of the epoxy group-containing vinyl monomer-derived group may also be used.

[0045] The vinyl alcohol resin (A) may be used alone or in combination of two or more.

[0046] As the vinyl alcohol resin (A), commercially available products may be used.

[0047] The method for producing the vinyl alcohol resin (A) is not particularly limited, and for example, a known method such as a method of saponifying a vinyl ester polymer may be used. The polymerization method for the vinyl ester polymer is not particularly limited, and examples thereof include conventionally known bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., but solution polymerization (e.g., solution polymerization using methanol as a solvent) is industrially preferred. For the solution polymerization, known initiators such as peroxides and azo initiators can be used, and the degree of polymerization of the resulting vinyl ester polymer can be adjusted by changing the blending ratio of the vinyl ester monomer to the solvent and the polymerization yield.

[0048] As a method for saponifying a vinyl ester polymer, a conventionally known method using an alkali catalyst or an acid catalyst can be used. Among these, an industrially preferred method is to add an alkali such as sodium hydroxide to a methanol solution of a vinyl ester polymer or a mixed solution of a vinyl ester polymer in methanol, water, methyl acetate, etc., and then perform alcoholysis while stirring. Thereafter, the resulting lumps, gels, or granules may be pulverized, and the alkali added as needed may be neutralized. Thereafter, the solid and liquid components may be separated, and the solid may be dried to obtain a PVA-based resin. When modification is carried out, the timing of modification is not particularly limited, and the modification may be carried out either before or after the saponification of the vinyl ester polymer.

[0049] Representative examples of the vinyl alcohol resin (A) include saponified vinyl ester polymers containing at least a vinyl ester and diacetone (meth)acrylamide as polymerization components; saponified vinyl ester polymers containing at least a vinyl ester having 3 or more carbon atoms in the side chain group as polymerization components; and saponified vinyl ester polymers having polyoxyalkylene modifications (polyoxyethylene groups, etc.). Among these, saponified vinyl ester polymers containing at least a vinyl ester and diacetone (meth)acrylamide as polymerization components are preferred.

[0050] In the vinyl alcohol-based resin (A), the proportion of side chain groups having 3 or more carbon atoms may be, for example, 0.05 mol % or more, preferably 0.1 mol % or more, more preferably 0.2 mol % or more, and particularly preferably 0.5 mol % or more, calculated as the polymerization component (monomer), from the viewpoint of reducing microdefects. In the vinyl alcohol resin (A), the proportion of side chain groups having 3 or more carbon atoms may be, for example, 50 mol % or less (e.g., 40 mol % or less, 30 mol % or less, 20 mol % or less, 15 mol % or less, 10 mol % or less) calculated as a polymerization component (monomer) from the viewpoint of polishing rate, etc.

[0051] These upper and lower limits may be appropriately combined to set an appropriate range (for example, 0.05 to 50 mol %, 0.05 to 40 mol %, etc.) (the same applies to other ranges). Specifically, in the vinyl alcohol resin (A), the proportion of side chain groups having 3 or more carbon atoms may be, in terms of polymerization components (monomers), for example, 0.05 to 20 mol %, preferably 0.1 to 20 mol %, more preferably 0.2 to 20 mol %, and particularly preferably 0.2 to 15 mol % (e.g., 1 to 10 mol %, 3 to 6 mol %).

[0052] In particular, when the vinyl alcohol-based resin (A) contains a group derived from diacetone (meth)acrylamide, from the viewpoint of improving haze, the proportion of the group derived from diacetone (meth)acrylamide in the vinyl alcohol-based resin (A) may be, for example, 0.05 to 50 mol %, preferably 0.2 to 20 mol % (e.g., 0.2 to 15 mol %, 1 to 10 mol %, 3 to 6 mol %) in terms of the polymerization components (monomers).

[0053] The degree of saponification of the vinyl alcohol resin (A) is not particularly limited, but may be, for example, 60 mol% or more (e.g., 70 mol% or more), preferably 80 mol% or more (e.g., 81 mol% or more, 82 mol% or more, 83 mol% or more, 84 mol% or more, 85 mol% or more), and more preferably 90 mol% or more (e.g., 91 mol% or more, 92 mol% or more, 93 mol% or more, 94 mol% or more, 95 mol% or more, 96 mol% or more, 97 mol% or more, 98 mol% or more). Although it is considered preferable that the degree of saponification of the vinyl alcohol resin is relatively high from the viewpoint of water solubility (solubility in the polishing liquid), research by the present inventors has shown that if the degree of saponification is too high, microdefects on the wafer surface after surface polishing of the silicon wafer are likely to increase. On the other hand, in the present invention, by using a vinyl alcohol resin (A) having a side chain group with 3 or more carbon atoms, microdefects on the wafer surface are likely to be reduced even when the degree of saponification of the vinyl alcohol resin is relatively high.

[0054] The upper limit of the saponification degree of the vinyl alcohol resin (A) is not particularly limited, but may be, for example, 99.9 mol % or less, 99.5 mol % or less, or 99 mol % or less.

[0055] The saponification degree of the vinyl alcohol resin (A) may be set to an appropriate range (e.g., 80 to 99.9 mol%, 85 to 99 mol%, 90 to 99 mol%, etc.) by appropriately combining these upper and lower limit values ​​(the same applies to others), and all combinations of the above upper and lower limit values ​​are included.

[0056] The degree of saponification of the vinyl alcohol resin (A) may be measured, for example, by the saponification degree measuring method of JIS K6726.

[0057] The average degree of polymerization of the vinyl alcohol resin (A) is not particularly limited, but may be, for example, 100 to 4,000, preferably 200 to 3,000, more preferably 300 to 2,000, and particularly preferably 500 to 1,000. According to the research of the present inventors, a vinyl alcohol-based resin with a relatively high average degree of polymerization was considered preferable from the viewpoint of enhancing the protection of the wafer surface and reducing damage to the wafer, but when a vinyl alcohol-based resin with a high average degree of polymerization is used to polish the surface of a silicon wafer, microdefects on the wafer surface tend to increase. On the other hand, in the present invention, by using a vinyl alcohol-based resin (A) having a side chain group with 3 or more carbon atoms, microdefects on the wafer surface can be easily reduced even when the vinyl alcohol-based resin has a relatively high average degree of polymerization.

[0058] The average degree of polymerization of the vinyl alcohol resin (A) may be measured, for example, by the method specified in JIS K6726.

[0059] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (A) at 20°C is not particularly limited, but may be, for example, 300 mPa·s or less (e.g., 250 mPa·s or less), preferably 200 mPa·s or less (e.g., 150 mPa·s or less), and more preferably 100 mPa·s or less (e.g., 50 mPa·s or less).

[0060] The lower limit of the viscosity of the vinyl alcohol resin (A) in a 4% aqueous solution at 20° C. is not particularly limited, but may be, for example, 1 mPa·s or more, or 3 mPa·s or more.

[0061] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (A) at 20°C may be set within an appropriate range (e.g., 1 to 300 mPa·s, 1 to 250 mPa·s, etc.) by appropriately combining these upper and lower limit values ​​(the same applies to other values), and all combinations of the above upper and lower limit values ​​are included.

[0062] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (A) at 20° C. may be measured, for example, by the method specified in JIS K 6726 (1994).

[0063] The number average molecular weight of the vinyl alcohol resin (A) is not particularly limited, and may be, for example, 10,000 or more, 20,000 or more, 30,000 or more, 40,000 or more, 50,000 or more.

[0064] The lower limit of the number average molecular weight of the vinyl alcohol resin (A) is not particularly limited, but may be, for example, 200,000 or less, or 100,000 or less.

[0065] The number average molecular weight of the vinyl alcohol resin (A) may be measured, for example, by GPC (for example, aqueous, polyethylene glycol equivalent).

[0066] The weight average molecular weight (Mw) of the vinyl alcohol resin (A) is not particularly limited, but for example, when the vinyl alcohol resin (A) has a polyoxyethylene group, the weight average molecular weight (Mw) of the vinyl alcohol resin (A) may be, for example, 5,000 to 200,000, preferably 10,000 to 100,000 (e.g., 10,000 to 30,000, 35,000 to 80,000), and more preferably 15,000 to 60,000 (e.g., 20,000 to 40,000).

[0067] The weight average molecular weight of the vinyl alcohol resin (A) may be measured, for example, by GPC (for example, aqueous, polyethylene glycol equivalent).

[0068] In the composition, the water-soluble polymer may contain at least one vinyl alcohol resin (B) selected from a vinyl alcohol resin (B1) having a degree of saponification of more than 90 mol% and a 4% aqueous solution viscosity at 20°C of 300 mPa·s or less, and a vinyl alcohol resin (B2) having a degree of saponification of 90 mol% or less.

[0069] (Vinyl alcohol resin (B)) The vinyl alcohol resin (B) is a saponified vinyl ester polymer, similar to the vinyl alcohol resin (A) described above. The vinyl ester and other monomers in the vinyl ester polymer may be those exemplified in the vinyl alcohol resin (A) described above.

[0070] A typical example of the vinyl alcohol resin (B) is a saponified vinyl ester polymer containing a vinyl ester as at least one polymerization component.

[0071] The vinyl alcohol resin (B) may have a side chain group having 3 or more carbon atoms (for example, a side chain group derived from diacetone (meth)acrylamide). The side chain group having 3 or more carbon atoms may be any of the groups exemplified for the vinyl alcohol resin (A). The vinyl alcohol resin (B) may be modified with a vinyl ester-derived unit or a unit derived from another monomer, as long as the effects of the present invention are not impaired. For example, the vinyl ester-derived unit may be modified by acetalization, etherification, acetoacetylation, cationization, polyoxyalkylene modification, or the like.

[0072] As described above, the vinyl alcohol resin (B) may contain units other than vinyl alcohol units and vinyl ester units, but the range of these units is preferably less than 1 mol %, and it is preferable that the resin (B) consists essentially of vinyl alcohol units and vinyl ester units.

[0073] The vinyl alcohol resin (B) may be used alone or in combination of two or more.

[0074] As the vinyl alcohol resin (B), commercially available products may be used.

[0075] The method for producing the vinyl alcohol resin (B) may be the same as the method for producing the vinyl alcohol resin (A) exemplified above.

[0076] (Vinyl alcohol resin (B1)) The saponification degree of the vinyl alcohol resin (B1) is, for example, more than 90 mol%, and may be 91 mol% or more, 92 mol% or more, 93 mol% or more, 94 mol% or more, 95 mol% or more, 96 mol% or more, 97 mol% or more, 98 mol% or more, etc. Such a vinyl alcohol resin having a relatively high degree of saponification does not easily undergo a saponification reaction in an aqueous solution, and therefore a polishing composition having excellent storage stability can be easily obtained, and pH fluctuations of the polishing composition can be easily reduced.

[0077] The upper limit of the saponification degree of the vinyl alcohol resin (B1) is not particularly limited, and may be, for example, 99.9 mol % or less, 99.5 mol % or less, or 99 mol % or less.

[0078] The saponification degree of the vinyl alcohol resin (B1) may be set within an appropriate range (e.g., 90 to 99.9 mol%, 91 to 99 mol%, 92 to 99 mol%, etc.) by appropriately combining these upper and lower limit values ​​(the same applies to others), and all combinations of the above upper and lower limit values ​​are included.

[0079] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (B1) at 20°C may be relatively low from the viewpoint of reducing microdefects, for example, 300 mPa·s or less (e.g., 250 mPa·s or less), preferably 200 mPa·s or less (e.g., 180 mPa·s or less), more preferably 150 mPa·s or less (e.g., 100 mPa·s or less), and particularly preferably 50 mPa·s or less (e.g., 40 mPa·s or less, 30 mPa·s or less, 20 mPa·s or less, 15 mPa·s or less). According to the research of the present inventors, when a vinyl alcohol-based resin with a high degree of saponification is used, the number of microdefects on the surface of a silicon wafer after surface polishing is likely to increase in some cases. However, in the present invention, by making the viscosity of a 4% aqueous solution of the vinyl alcohol-based resin (B1) at 20°C relatively low, it is possible to easily reduce the number of microdefects on the wafer surface even when the vinyl alcohol-based resin (B1) has a high degree of saponification.

[0080] The lower limit of the viscosity of the vinyl alcohol resin (B1) in a 4% aqueous solution at 20°C is not particularly limited, and may be, for example, 0.5 mPa·s or more, 1 mPa·s or more, 2 mPa·s or more, 5 mPa·s or more, 10 mPa·s or more, 15 mPa·s or more, 20 mPa·s or more, 25 mPa·s or more, 30 mPa·s or more, 40 mPa·s or more, or 50 mPa·s or more.

[0081] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (B1) at 20°C may be set within an appropriate range (e.g., 0.5 to 300 mPa·s, 1 to 200 mPa·s, 2 to 50 mPa·s, etc.) by appropriately combining these upper and lower limits (the same applies to other values), and all combinations of the above upper and lower limits are included.

[0082] Furthermore, the viscosity of a 4% aqueous solution of the vinyl alcohol resin (B1) at 20°C may be relatively high (e.g., 30 mPa·s or more, 40 mPa·s or more, 50 mPa·s or more, etc.) from the overall viewpoint of LLS defects, AFM roughness, and haze, even if it is 300 mPa·s or less. On the other hand, from the viewpoint of suppressing viscosity increase during storage, suppressing gelation, and ease of handling in aqueous solution, the viscosity may be relatively low (e.g., 40 mPa·s or less, less than 40 mPa·s, 30 mPa·s or less, less than 30 mPa·s, 25 mPa·s or less, less than 25 mPa·s, 20 mPa·s or less, etc.).

[0083] The average degree of polymerization of the vinyl alcohol resin (B1) is not particularly limited, and may be, for example, 100 to 4000, preferably 200 to 3500, more preferably 300 to 3000, and particularly preferably 500 to 2500 (e.g., 600 to 2300, 1000 to 2000), etc.

[0084] The weight average molecular weight of the vinyl alcohol resin (B1) is not particularly limited, but for example, the weight average molecular weight of a vinyl alcohol resin (B1) having a degree of saponification of 95 mol% or more may be, for example, 4,000 to 176,000, preferably 44,000 or more, and from the viewpoint of improving LLS defects on the surface after polishing, it may be more preferably 44,000 to 88,000, and from the viewpoint of improving AFM roughness on the surface after polishing, it may be more preferably 155,000 to 176,000.

[0085] (Vinyl alcohol resin (B2)) The degree of saponification of the vinyl alcohol resin (B2) may be, for example, 90 mol% or less, 89 mol% or less, 88 mol% or less, 87 mol% or less, 86 mol% or less, or 85 mol% or less, from the viewpoint of reducing microdefects. Such a vinyl alcohol resin having a relatively low degree of saponification can easily suppress an increase in viscosity due to storage of an aqueous vinyl alcohol resin solution that is a raw material for the polishing composition.

[0086] The lower limit of the saponification degree of the vinyl alcohol resin (B2) is not particularly limited, and may be, for example, 60 mol% or more, 65 mol% or more, 70 mol% or more, 75 mol% or more, or 80 mol% or more.

[0087] The saponification degree of the vinyl alcohol resin (B2) may be set within an appropriate range (e.g., 60 to 90 mol%, 65 to 89 mol%, 70 to 89 mol%, etc.) by appropriately combining these upper and lower limit values ​​(the same applies to others), and all combinations of the above upper and lower limit values ​​are included.

[0088] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (B2) at 20°C is not particularly limited, but may be, for example, 2000 mPa·s or less, 1000 mPa·s or less, 500 mPa·s or less, 300 mPa·s or less, 100 mPa·s or less, 50 mPa·s or less, or the like. The viscosity of a 4% aqueous solution of the vinyl alcohol resin (B2) at 20°C may be relatively high. According to the research of the present inventors, it was thought that a vinyl alcohol-based resin having a relatively high viscosity in 4% aqueous solution at 20° C. would be preferable from the viewpoint of enhancing the protection of the wafer surface and reducing damage to the wafer, but when a vinyl alcohol-based resin having a high viscosity in 4% aqueous solution at 20° C. is used to polish the surface of a silicon wafer, the number of microdefects on the wafer surface tends to increase. On the other hand, in the present invention, by using a vinyl alcohol-based resin (B2) having a relatively low degree of saponification, it is easy to reduce microdefects on the wafer surface even when the viscosity of a 4% aqueous solution of the vinyl alcohol-based resin at 20° C. is relatively high.

[0089] The lower limit of the viscosity of a 4% aqueous solution of the vinyl alcohol resin (B2) at 20° C. is not particularly limited, and may be, for example, 0.5 mPa·s or more, 1 mPa·s or more, or 2 mPa·s or more.

[0090] The viscosity of a 4% aqueous solution of the vinyl alcohol resin (B2) at 20°C may be set within an appropriate range (e.g., 0.5 to 2000 mPa·s, 1 to 1000 mPa·s, 2 to 500 mPa·s, etc.) by appropriately combining these upper and lower limits (the same applies to other values), and all combinations of the above upper and lower limits are included.

[0091] The average degree of polymerization of the vinyl alcohol resin (B2) is not particularly limited, and may be, for example, 100 to 9000, preferably 1800 to 8800, more preferably 3700 to 8500, and particularly preferably 4000 to 8000 (for example, 4000 to 5000).

[0092] The weight-average molecular weight of the vinyl alcohol-based resin (B2) is not particularly limited, but for example, the weight-average molecular weight of the vinyl alcohol-based resin (B2) having a degree of saponification of about 88 mol% (e.g., 85 to 90 mol%) may be preferably 82,000 or more, more preferably 182,000 to 417,000 (e.g., 196,000 to 245,000), from the viewpoint of reducing the number of LLS defects on the surface after polishing and reducing AFM roughness. The weight average molecular weight of the vinyl alcohol resin (B2) having a saponification degree of 75 mol % or more and less than 81 mol % may be preferably 30,000 or more and 25,000 or less. The weight average molecular weight of the vinyl alcohol resin (B2) having a degree of saponification of less than 75 mol % may preferably be 10,000 or more.

[0093] The methods for measuring the degree of saponification of the vinyl alcohol-based resin (B), the method for measuring the viscosity of a 4% aqueous solution at 20°C, the method for measuring the average degree of polymerization, and the method for measuring the weight-average molecular weight of the vinyl alcohol-based resin (B) may be the same as those for the vinyl alcohol-based resin (A) exemplified above.

[0094] As the water-soluble polymer, one or more types selected from vinyl alcohol resins (A) and (B) may be used.

[0095] The composition may further contain a water-soluble polymer other than the vinyl alcohol resins (A) and (B) described above.

[0096] Examples of other water-soluble polymers include, but are not limited to, vinyl alcohol-based resins not included in the scope of the vinyl alcohol-based resins (A) and (B), cellulose derivatives (e.g., methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose), starch derivatives (e.g., pullulan, cyclodextrin), imine derivatives [e.g., poly(N-acylalkyleneimine)], polyvinylpyrrolidone-based resins, polyvinyl caprolactam-based resins, acrylic resins, polyacryloylmorpholine-based resins, and polyoxyalkylenes (e.g., polyoxyethylene).

[0097] The other water-soluble polymers may be used alone or in combination of two or more.

[0098] (surfactant) The composition may further comprise a surfactant. The use of a surfactant can improve the dispersion stability of the composition and also tends to reduce micro-defects and haze on the polished surface.

[0099] The molecular weight of the surfactant is set to 1×10 from the viewpoint of the dispersibility of the composition and the cleaning property of the object to be polished. 4 The following is preferred: The lower limit of the molecular weight of the surfactant can be selected as appropriate depending on the type of surfactant, etc., but is, for example, 200 or more. From the viewpoint of the effect of reducing microdefects and haze on the surface, etc., it is preferably 250 or more, more preferably 300 or more (for example, 500 or more), even more preferably 2000 or more, and particularly preferably 5000 or more.

[0100] Specifically, the molecular weight of the surfactant may be, for example, 200 to 10,000, preferably 250 to 10,000, and more preferably 300 to 10,000 (eg, 2,000 to 10,000, 5,000 to 10,000).

[0101] The molecular weight of the surfactant can be the weight average molecular weight (Mw) (water-based, polyethylene glycol equivalent) determined by GPC or the molecular weight calculated from the chemical formula.

[0102] The surfactant may be a water-soluble polymer having a molecular weight within the range exemplified above (for example, another water-soluble polymer exemplified above).

[0103] Specific surfactants include, for example, anionic surfactants and nonionic surfactants, with nonionic surfactants being preferred from the standpoint of low foaming properties and ease of pH adjustment.

[0104] Examples of nonionic surfactants include copolymers of multiple types of oxyalkylene (e.g., multiple types of oxy C such as diblock type, triblock type, random type, and alternating type). 2-6 Alkylene, preferably oxyC 2-3alkylene copolymers), oxyalkylene polymers (e.g., polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc.), polyoxyalkylene adducts {e.g., polyoxyethylene adducts [e.g., polyoxyethylene alkyl ethers (e.g., 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), polyoxyethylene phenyl ether, polyoxyethylene alkyl phenyl ethers (e.g., polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene ethylene dodecyl phenyl ether), polyoxyethylene styrenated phenyl ether, polyoxyethylene alkylamines (e.g., polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine), polyoxyethylene alkylamides (e.g., polyoxyethylene stearylamide, polyoxyethylene oleylamide), polyoxyethylene fatty acid esters (e.g., polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate), polyoxyethylene glyceryl ether fatty acid esters, polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate), polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil,Polyoxy C, such as polyoxyethylene hydrogenated castor oil, 2-6 Alkylene adducts, preferably polyoxy C 2-3 alkylene adducts}, acetylene glycol surfactants [for example, alkylene oxide (e.g., ethylene oxide) adducts of acetylene glycol], and the like.

[0105] Examples of copolymers of multiple types of oxyalkylene include copolymers having an oxyethylene (EO) structure and an oxypropylene (PO) structure (copolymers having an EO-PO structure) {for example, block copolymers of EO and PO [for example, diblock copolymers, polyoxyethylene (PEO)-polyoxypropylene (PPO)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.], random copolymers of EO and PO, etc.}.

[0106] Among these nonionic surfactants, copolymers having an EO-PO structure, polyoxyethylene alkyl ethers, acetylene glycol surfactants, etc. are preferred, and block copolymers of EO and PO (particularly PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ether), etc. are particularly preferred.

[0107] As the PEO-PPO-PEO triblock polymer, a polymer represented by the following general formula (2) can be preferably used. HO-(EO)a-(PO)b-(EO)cH···(2) In general formula (2), EO represents an oxyethylene unit (-CH2CH2O-), PO represents an oxypropylene unit (-CH2CH(CH3)O-) group, and a, b, and c each represent an integer of 1 or more (typically 2 or more). In the general formula (2), the sum of a and c is preferably in the range of 2 to 1,000, more preferably in the range of 5 to 500, and even more preferably in the range of 10 to 200. In general formula (2), b is preferably in the range of 2 to 200, more preferably in the range of 5 to 100, and even more preferably in the range of 10 to 50.

[0108] In a block copolymer or random copolymer of EO and PO, the molar ratio of EO to PO (EO / PO) constituting the copolymer is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more (for example, 5 or more), from the viewpoints of solubility in water, washability, etc.

[0109] As the acetylene glycol surfactant, for example, Surfynol 400 series manufactured by Nissin Chemical Industry Co., Ltd. can be used.

[0110] The surfactants may be used alone or in combination of two or more.

[0111] The HLB value of the surfactant is not particularly limited, but may be, for example, 8-20, preferably 10-20, and more preferably 15-20.

[0112] (abrasive grain) The composition may include an abrasive. The abrasive grains are not particularly limited, but examples thereof include inorganic particles [e.g., inorganic oxides {e.g., metal oxides (e.g., alumina, cerium oxide, chromium oxide, titanium dioxide, zirconium oxide, magnesium oxide, manganese dioxide, zinc oxide, red iron oxide), semi-metallic oxides (e.g., silica)}, metal hydroxides [e.g., rare earth metal hydroxides (e.g., cerium hydroxide), zirconium hydroxide], inorganic nitrides (e.g., silicon nitride, boron nitride), inorganic carbides (e.g., silicon carbide, boron carbide), , inorganic carbonates {e.g., metal carbonates such as alkali metal carbonates (e.g., sodium carbonate, potassium carbonate), alkaline earth metal carbonates (e.g., calcium carbonate, barium carbonate)}, diamond, etc.}, organic particles [e.g., polymers of unsaturated acids (e.g., poly(meth)acrylic acid), (meth)acrylic acid ester polymers {e.g., poly(meth)acrylic acid alkyl esters (e.g., polymethyl methacrylate)}, polyacrylonitrile, etc.], organic-inorganic composite particles, etc.

[0113] Among these abrasive grains, inorganic particles are preferred, inorganic oxides (e.g., metal oxides, semi-metal oxides) are more preferred, and silica (e.g., colloidal silica, fumed silica, precipitated silica) is particularly preferred. Therefore, the abrasive grains may contain at least silica. When the abrasive grains contain silica, the proportion of silica in the abrasive grains may be, for example, 50% by weight or more (e.g., 60% by weight or more), 70% by weight or more (80% by weight or more), 90% by weight or more (95% by weight or more, 99% by weight or more), etc. Among silicas, colloidal silica, fumed silica, and the like are preferred from the viewpoint of making the surface of the object to be polished less prone to scratches and realizing a surface with lower haze, and colloidal silica is more preferred from the viewpoint of being able to suppress scratches, and high-purity colloidal silica is particularly preferred from the viewpoint of preventing metal contamination.

[0114] The abrasive grains may be used alone or in combination of two or more kinds.

[0115] The particle form of the abrasive grains is not particularly limited, and may be any of primary particles, secondary particles, or a mixture of both, and preferably may be a form containing at least secondary particles.

[0116] Average primary particle diameter of abrasive grains D P1 is not particularly limited, but may be, for example, 5 nm or more, preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more, from the viewpoint of polishing rate and the like. In addition, from the viewpoint of reducing haze, the average primary particle diameter D P1 may be preferably less than 100 nm, more preferably 50 nm or less, and even more preferably 40 nm or less.

[0117] The average primary particle diameter of the abrasive grains D P1 Alternatively, these upper and lower limit values ​​may be appropriately combined to set an appropriate range (for example, 5 nm to 50 nm, 5 nm to 40 nm, etc.) (the same applies to other ranges).

[0118] Average primary particle diameter of abrasive grains D P1 is the specific surface area S (m 2 / g), D P1 = 2720 / S (nm). The method for measuring the specific surface area is not particularly limited, and for example, the specific surface area can be measured using a surface area measuring device manufactured by Micromeritics, trade name "Flow Sorb II 2300".

[0119] Average secondary particle diameter D of abrasive grains P2 is not particularly limited, but may be, for example, 10 nm or more, preferably 20 nm or more, from the viewpoint of polishing rate and the like. In addition, the average secondary particle diameter of the abrasive grains D P2 From the viewpoint of obtaining a higher polishing effect, the thickness may be more preferably 30 nm or more, further preferably 35 nm or more, and particularly preferably 40 nm or more (for example, more than 40 nm).

[0120] In addition, the average secondary particle diameter of the abrasive grains DP2 From the viewpoint that particles of a size suitable for reducing micro defects are likely to exist in the polishing composition, the particle size may be, for example, less than 100 nm, preferably 90 nm or less, and more preferably 80 nm or less.

[0121] The average secondary particle diameter of the abrasive grains D P2 Alternatively, these upper and lower limit values ​​may be appropriately combined to set an appropriate range (for example, 10 nm to 90 nm, 20 nm to 80 nm, etc.) (the same applies to other values).

[0122] Average secondary particle diameter D of abrasive grains P2 can be measured by a laser diffraction scattering method using, for example, a model "UPA-UT151" manufactured by Nikkiso Co., Ltd., using an aqueous dispersion of the target abrasive grains (not containing a water-soluble polymer) as a measurement sample.

[0123] Average secondary particle diameter D of abrasive grains P2 is the average primary particle diameter of the abrasive grains D P1 Equal to or greater than (D P2 / D P1 ≧1), and D P1 greater than (D P2 / D P1 >1) may also be used. Abrasive grain D P2 / D P1 is preferably in the range of 1 to 3 from the viewpoint of the polishing effect and the surface smoothness after polishing.

[0124] The shape (external shape) of the abrasive grains is not particularly limited, but may be spherical or non-spherical (for example, peanut-shaped (i.e., peanut shell-shaped), cocoon-shaped, sugar candy-shaped, or rugby ball-shaped).

[0125] The average value of the long axis / short axis ratio (average aspect ratio) of the primary particles of the abrasive grains is not particularly limited, but from the viewpoint of polishing speed etc., it is preferably 1.0 or more, more preferably 1.05 or more, and even more preferably 1.1 or more. The average aspect ratio of the abrasive grains is preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.5 or less, from the viewpoint of reducing scratches.

[0126] The shape (outline) and average aspect ratio of abrasive grains can be determined, for example, by electron microscope observation. Specifically, for example, using a scanning electron microscope (SEM), a predetermined number (e.g., 200) of abrasive grains whose individual particle shapes can be recognized are circumscribed by a smallest rectangle that circumscribes each particle image. The rectangle drawn for each particle image is then divided by the length of its long side (long diameter) by the length of its short side (short diameter) to calculate the long diameter / short diameter ratio (aspect ratio). The average aspect ratio can be determined by arithmetically averaging the aspect ratios of the predetermined number of particles.

[0127] (pH adjuster) The composition may also include a pH adjuster. As the pH adjuster, a basic compound is preferred from the viewpoints of chemical polishing of the surface of the object to be polished, improving the polishing rate, and improving the dispersion stability of the composition. The pH of the composition can be increased by using a basic compound.

[0128] Examples of the basic compound include nitrogen-containing organic or inorganic basic compounds [e.g., quaternary ammonium hydroxide or a salt thereof (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc.), ammonia, amines {e.g., methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, guanidine, etc.}, azoles (e.g., anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, imidazole, triazole, etc.}, etc.], hydroxides of alkali metals or alkaline earth metals (e.g., potassium hydroxide, sodium hydroxide, etc.), carbonates (e.g., ammonium carbonate, potassium carbonate, sodium carbonate, etc.), and bicarbonates (e.g., ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, etc.).

[0129] Among these basic compounds, from the viewpoint of improving the polishing rate, etc., ammonia, hydroxides of alkali metals (e.g., potassium hydroxide, sodium hydroxide, etc.), quaternary ammonium hydroxides or salts thereof (e.g., tetramethylammonium hydroxide, tetraethylammonium hydroxide, etc.), carbonates (e.g., ammonium carbonate, potassium carbonate, sodium carbonate, etc.), bicarbonates (e.g., ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, etc.), etc. are preferred, ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, etc. are more preferred, ammonia, tetramethylammonium hydroxide, etc. are even more preferred, and ammonia is particularly preferred.

[0130] The basic compounds may be used singly or in combination of two or more.

[0131] (solvent) The composition may include a solvent. The solvent is not particularly limited, but examples thereof include water and organic solvents (such as lower alcohols and lower ketones). The solvent preferably contains at least water. The content of water in the entire solvent is preferably 90% by volume or more, more preferably 95% by volume or more (for example, 99 to 100% by volume).

[0132] As the water, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc. can be preferably used. In order to avoid as much as possible the inhibition of the functions of other components contained in the composition, the water preferably has a total transition metal ion content of 100 ppb or less. The water may be purified by, for example, removing impurity ions with an ion exchange resin, removing foreign matter with a filter, or by distillation.

[0133] (Other ingredients) The composition may contain other ingredients in addition to the above ingredients (water-soluble polymer, abrasive grains, pH adjuster, surfactant, and solvent). The other components are not particularly limited, but examples thereof include additives such as chelating agents, organic acids, organic acid salts, inorganic acids, inorganic acid salts, preservatives, and antifungal agents.

[0134] Examples of the chelating agent include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents.

[0135] Examples of aminocarboxylic acid chelating agents include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate.

[0136] Examples of organic phosphonic acid chelating agents include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, and α-methylphosphonosuccinic acid.

[0137] Among these chelating agents, organic phosphonic acid chelating agents are more preferred, with ethylenediaminetetrakis(methylenephosphonic acid) and diethylenetriaminepenta(methylenephosphonic acid) being particularly preferred.

[0138] Examples of organic acids include fatty acids (e.g., formic acid, acetic acid, propionic acid, etc.), aromatic carboxylic acids (e.g., benzoic acid, phthalic acid, etc.), citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, fumaric acid, succinic acid, organic sulfonic acids, and organic phosphonic acids. Examples of organic acid salts include alkali metal salts of organic acids (such as sodium salts and potassium salts), and ammonium salts of organic acids.

[0139] Examples of inorganic acids include sulfuric acid, nitric acid, hydrochloric acid, and carbonic acid. Examples of inorganic acid salts include alkali metal salts of inorganic acids (such as sodium salts and potassium salts), and ammonium salts of inorganic acids.

[0140] Examples of the antiseptic and antifungal agent include isothiazolinone compounds, paraoxybenzoic acid esters, and phenoxyethanol.

[0141] The other components may be used alone or in combination of two or more.

[0142] (Embodiments of the composition) As will be described later, the composition may be used as a polishing liquid as it is, or may be diluted with a solvent (for example, diluted at a dilution ratio as will be described later) and used as a polishing liquid. That is, the composition may be low in concentration (polishing solution) or high in concentration (polishing concentrate). The high-concentration composition may be a concentrate of the low-concentration composition.

[0143] In the composition, the proportion of the water-soluble polymer (proportion of the water-soluble polymer relative to the entire composition) is not particularly limited, but may be, for example, 1 ppm or more by mass, and from the viewpoint of reducing haze, may be preferably 3 ppm or more, and more preferably 5 ppm or more (e.g., 10 ppm or more). Furthermore, in the composition, the proportion of the water-soluble polymer may be preferably 1000 ppm or less, more preferably 500 ppm or less (for example, 300 ppm or less) on a mass basis, from the viewpoint of the removal rate and the like. An appropriate range may be set by appropriately combining these upper and lower limits, and the proportion of the water-soluble polymer in the composition may be, specifically, for example, 1 ppm to 1000 ppm, preferably 3 ppm to 500 ppm, and more preferably 5 ppm to 300 ppm.

[0144] The proportion of the water-soluble polymer can be appropriately set depending on the dilution ratio, for example, in a high-concentration composition, and is not particularly limited, but may be, for example, 1000 ppm or more, preferably 1500 ppm or more, and more preferably 2000 ppm or more, on a mass basis. In addition, in a high-concentration composition, the proportion of the water-soluble polymer may be preferably 20,000 ppm or less, more preferably 10,000 ppm or less, on a mass basis. Note that an appropriate range may be set by appropriately combining these upper and lower limits, and in a high-concentration composition, the proportion of the water-soluble polymer may be, specifically, for example, 1000 ppm to 20000 ppm, preferably 1500 ppm to 10000 ppm, and more preferably 2000 ppm to 5000 ppm.

[0145] When the composition contains abrasive grains, the proportion of the abrasive grains in the composition (proportion of the abrasive grains to the entire composition) is not particularly limited, but may be, for example, 0.01 mass % or more, preferably 0.05 mass % or more, and more preferably 0.1 mass % or more (e.g., 0.15 mass % or more, 0.2 mass % or more, 0.4 mass % or more, 0.6 mass % or more, 0.8 mass % or more). By increasing the content of abrasive grains, a higher polishing rate can be achieved. Furthermore, in order to achieve a surface with lower haze, the proportion of abrasive grains in the composition may be, for example, 10% by mass or less, preferably 7% by mass or less, and more preferably 5% by mass or less. These upper and lower limits may be appropriately combined to set an appropriate range, and the abrasive content includes all combinations of the upper and lower limits. Specifically, the abrasive content in the composition may be, for example, 0.01% to 10% by mass, preferably 0.05% to 7% by mass, and more preferably 0.1% to 5% by mass. In particular, in the case of a composition containing a vinyl alcohol resin (A) having a polyoxyethylene group and silica, the proportion of silica in the composition may be, for example, more than 0.2% by mass and not more than 7% by mass (e.g., more than 0.2% by mass and not more than 5% by mass), preferably more than 0.3% by mass and not more than 6% by mass (e.g., more than 0.3% by mass and not more than 4% by mass), and more preferably more than 0.4% by mass and not more than 5% by mass (e.g., more than 0.5% by mass and not more than 4% by mass, more than 0.6% by mass and not more than 3% by mass).

[0146] The proportion of abrasive grains can be set appropriately depending on the dilution ratio, for example, in a high-concentration composition, and is not particularly limited, but may be, for example, 0.2 mass% or more, preferably 1 mass% or more, and more preferably 2 mass% or more. In addition, in a highly concentrated composition, the proportion of abrasive grains may be, for example, 50% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less. These upper and lower limits may be appropriately combined to set an appropriate range, and the proportion of abrasive grains in a high-concentration composition may be, for example, 0.2% by mass to 50% by mass, 1% by mass to 20% by mass, or 2% by mass to 10% by mass.

[0147] When the composition contains a pH adjuster, the proportion of the pH adjuster in the composition (the proportion of the pH adjuster relative to the entire composition) is not particularly limited, but may be, for example, 1 ppm or more, preferably 5 ppm or more, from the viewpoint of the polishing rate, etc. Furthermore, in the composition, the proportion of the pH adjuster may be, for example, less than 1000 ppm, and preferably less than 500 ppm, from the viewpoint of reducing haze, etc. In addition, an appropriate range may be set by appropriately combining these upper and lower limits, and the proportion of the pH adjuster in the composition may be, for example, 1 ppm or more and less than 1000 ppm, or 5 ppm or more and less than 500 ppm.

[0148] The proportion of the pH adjuster can be set appropriately depending on the dilution ratio, for example, in a high-concentration composition, and is not particularly limited, but may be, for example, 20 ppm or more, preferably 100 ppm or more. In high concentration compositions, the proportion of the pH adjuster may be, for example, less than 20,000 ppm, preferably less than 10,000 ppm. In addition, an appropriate range may be set by appropriately combining these upper and lower limits, and in a high-concentration composition, the proportion of the pH adjuster may be, for example, 20 ppm or more and less than 20,000 ppm, preferably 100 ppm or more and less than 10,000 ppm.

[0149] When the composition contains a surfactant, the proportion of the surfactant in the composition (proportion of the surfactant relative to the entire composition) is not particularly limited, but from the viewpoint of the effect of improving microdefects on the surface and haze, it may be, for example, 0.1 ppm or more, preferably 0.5 ppm or more, more preferably 1 ppm or more (e.g., 3 ppm or more), and even more preferably 5 ppm or more (e.g., 10 ppm or more). Furthermore, in the composition, the proportion of the surfactant may be, for example, 1000 ppm or less, preferably 500 ppm or less (eg, 300 ppm or less), and more preferably 100 ppm or less, from the viewpoint of the removal rate and the like. An appropriate range may be set by appropriately combining these upper and lower limits, and the proportion of the surfactant in the composition may be, specifically, for example, 0.1 ppm to 1000 ppm, preferably 0.5 ppm to 500 ppm, and more preferably 1 ppm to 100 ppm.

[0150] The proportion of the surfactant can be set appropriately depending on the dilution ratio, for example, in a high-concentration composition, and is not particularly limited, but may be, for example, 2 ppm or more, preferably 10 ppm or more, more preferably 20 ppm or more, and even more preferably 100 ppm or more. In addition, in a high concentration composition, the proportion of the surfactant may be, for example, 20,000 ppm or less, preferably 10,000 ppm or less, and more preferably 2,000 ppm or less. An appropriate range may be set by appropriately combining these upper and lower limits, and in a high-concentration composition, the proportion of the surfactant may be, for example, 2 ppm to 20,000 ppm, preferably 10 ppm to 10,000 ppm, and more preferably 20 ppm to 2,000 ppm.

[0151] The solid content concentration of the composition is not particularly limited, but may be, for example, 0.01% by mass or more, preferably 0.01% by mass to 50% by mass, and more preferably 0.05% by mass to 40% by mass.

[0152] Furthermore, the solid content concentration of the composition can be set appropriately depending on the dilution ratio, for example, in the case of a high-concentration composition, and is not particularly limited, but may be, for example, 1% by mass or more, preferably 2% by mass to 50% by mass, and more preferably 5% by mass to 25% by mass.

[0153] The solid content concentration can be expressed as the mass ratio of the residue remaining in the composition after drying the composition at 105°C for 24 hours.

[0154] When the composition contains other components, the proportion of the other components in the composition (the proportion of the other components relative to the total composition) is not particularly limited, but may be, for example, 0.01 to 30 mass%, preferably 0.01 to 20 mass%, and more preferably 0.01 to 10 mass%.

[0155] Furthermore, the proportion of other components can be appropriately set depending on the dilution ratio, for example, in a high-concentration composition, and is not particularly limited, but may be, for example, 0.2 to 60 mass%, preferably 0.2 to 40 mass%, and more preferably 0.2 to 20 mass%.

[0156] When the composition contains abrasive grains, the ratio of the water-soluble polymer to the abrasive grains in the composition is not particularly limited, but the water-soluble polymer:abrasive grains (mass ratio) may be, for example, 10:1 to 1:1000, preferably 5:1 to 1:500, and more preferably 1:1 to 1:100.

[0157] When the composition contains a surfactant, the ratio of the water-soluble polymer to the surfactant in the composition is not particularly limited, but the water-soluble polymer:surfactant (mass ratio) may be, for example, 1:0.01 to 1:200, preferably 1:0.01 to 1:100 (e.g., 1:0.01 to 1:20, more preferably 1:0.05 to 1:15, and particularly preferably 1:0.1 to 1:10).

[0158] The zeta potential of the composition is, from the viewpoint of suppressing abrasive grain aggregation, for example, −0 mV or less, preferably −5 mV or less, and more preferably −10 mV or less, and from the viewpoint of polishing rate, for example, −100 mV or more, preferably −90 mV or more, and more preferably −80 mV or more. The zeta potential of the composition can be measured, for example, using an ultrasonic zeta potential measuring device DT-1202 manufactured by Dispersion Technology.

[0159] (Method of producing the composition) The method for producing the composition is not particularly limited, and for example, the components to be contained in the composition may be mixed. The mixing may be performed at room temperature or while heating. The mixing may be carried out with stirring, or may be carried out using a mixing device (for example, a blade stirrer, an ultrasonic disperser, a homomixer, or the like). The order in which the components in the composition are mixed is not particularly limited. For example, all the components may be mixed at once, or may be mixed in an appropriately set order.

[0160] In the process of preparing the composition, the composition may be filtered. The filtration may be carried out by filtering each component contained in the composition, or by filtering a mixture of the components. The filtration method is not particularly limited, and for example, filtration using a filter may be used. The filtration may be a circulation filtration.

[0161] (polishing) The polished article can be produced by polishing the surface of an object to be polished with the composition. The surface to be polished may be either one or both surfaces of the object to be polished. When polishing both sides of the object to be polished, both sides may be polished simultaneously, or one side may be polished at a time. A preferred embodiment of the method for polishing an object to be polished using the composition (method for producing an object to be polished) will be described below.

[0162] Examples of materials for the object to be polished include metals or semi-metals such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, and 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. Among these objects to be polished, those containing silicon (for example, single crystal silicon substrates) are preferred. The object to be polished may be made of a plurality of materials.

[0163] Although a coating may be formed on the object to be polished, in the present invention, it is preferable to polish the substrate itself (e.g., the substrate itself, rather than polishing a barrier layer formed on the substrate (e.g., a barrier layer such as tantalum for protecting an insulating layer)). Examples of coatings include polysilicon films, nitride films, and oxide films. The thickness of the coating may be, for example, more than 100 nm. The surface to be polished may also be a substrate in which part is oxidized (for example, one having a native oxide film with a thickness of 100 nm or less).

[0164] The shape of the object to be polished is not particularly limited, but it is preferable that the object has a flat surface, such as a plate or polyhedron.

[0165] The area of ​​the object to be polished is not particularly limited, but may be, for example, about 7,000 to about 200,000 mm 2 (For example, about 7850 to about 196250 mm 2 ), preferably about 17,000 to about 160,000 mm 2 (For example, approximately 17663 to approximately 158963 mm 2 ) etc.

[0166] As the polishing liquid used for polishing, the composition may be used as it is, or a liquid obtained by diluting the composition with a solvent may be used. The dilution solvent may be any of the solvents exemplified above, and is preferably a solvent containing at least water (aqueous solvent). The dilution solvent may be the same as or different from the solvent contained in the composition (the type of solvent or, in the case of a mixed solvent, the mixing ratio of each component). The dilution ratio may be, for example, about 2 to 100 times (e.g., about 5 to 50 times, or about 20 to 50 times) in volume terms, preferably 10 to 30 times, and more preferably 15 to 25 times.

[0167] The polishing liquid may have its pH adjusted using the pH adjusters listed above. The pH of the polishing liquid can be adjusted appropriately depending on the degree of saponification of the vinyl alcohol resin, the type of abrasive grains, etc., and is not particularly limited, but may be, for example, 8.0 to 12.0 (e.g., 9.0 to 11.0) or 5.0 to 9.0 (e.g., 6.0 to 8.0). The above pH is particularly preferably applied to polishing liquids used for polishing silicon wafers (e.g., polishing liquids for final polishing, etc.).

[0168] The polishing liquid is supplied to the object to be polished, and polishing can be carried out in a conventional manner. The composition can be particularly preferably used for polishing semiconductor substrates (particularly silicon wafers). The polishing process in which the composition is used is not particularly limited, but the composition is particularly suitable for, for example, final polishing of silicon wafers or polishing processes upstream thereof. Note that final polishing usually refers to the final polishing step in the manufacturing process of the target product (i.e., a step in which no further polishing is performed after that step). For example, it is effective to apply it to the polishing of silicon wafers that have been prepared to a surface roughness of 0.01 nm to 100 nm in an upstream step (typically the final polishing or the polishing immediately before), and application to the final polishing is particularly preferable.

[0169] For example, when performing final polishing of a silicon wafer, the silicon wafer that has been subjected to the lapping step and the primary and secondary polishing steps may be set in a general polishing apparatus, and a polishing liquid may be supplied to the surface of the silicon wafer (surface to be polished) through the polishing pad of the polishing apparatus. For example, while the polishing liquid is continuously supplied, the polishing pad may be pressed against the surface of the silicon wafer and the two may be moved relatively (for example, rotated).

[0170] (Washing) The polished product obtained as described above may be washed. The cleaning can be carried out, for example, using a cleaning solution. The cleaning liquid is not particularly limited, and when polishing a semiconductor substrate, for example, SC-1 cleaning liquid (a mixture of ammonium hydroxide (NH4OH), hydrogen peroxide (H2O2), and water (H2O)) commonly used in the semiconductor field can be used. The temperature of the cleaning liquid can be, for example, from room temperature to about 90°C.

[0171] (Abrasive) The present invention also includes an abrasive article that forms an abrasive surface as follows. The polished surface of such a polished object has a number of LLS defects of 26 nm or more within a diameter of 300 mm (i.e., the area of ​​a circle with a diameter of 300 mm: approximately 70650 mm 2 ) preferably satisfies 700 or less, more preferably 300 or less, and even more preferably 100 or less. The polishing material of the present invention may be a polishing material of the above-exemplified object to be polished (for example, a single crystal silicon substrate, etc.), but it is preferably not a polishing material of a nitrogen-doped single crystal silicon substrate, and it is preferably not a polishing material of a single crystal silicon substrate in which the Nv region and the Ni region are mixed.

[0172] The number of LLS defects of 26 nm or more can be measured, for example, by the method described in the Examples below.

[0173] In addition, the polished surface of the polished object has the number of LLS defects of 19 nm or more within a diameter of 300 mm (i.e., the area of ​​a circle with a diameter of 300 mm: approximately 70650 mm 2 ) preferably satisfies 850 or less, more preferably 550 or less, and even more preferably 250 or less.

[0174] The number of LLS defects of 19 nm or more can be measured, for example, by the method described in the Examples below.

[0175] The number of LLS defects is the number per 300 mm diameter, but the size of the object to be polished is not limited to a diameter of 300 mm.

[0176] The present invention focuses on surface defects of a smaller size that cannot be measured by wafer defect inspection systems manufactured by KLA-Tencor Corporation, such as "SP1" and "SP2," and can reduce the number of such small surface defects. However, the size of defects measured by SP1 and SP2 is larger than the size of defects that can be reduced by the present invention, and therefore cannot be compared to the present invention.

[0177] The haze of the polished surface of the polished article may be, for example, 0.3 ppm or less (e.g., less than 0.3 ppm), preferably 0.25 ppm or less (e.g., less than 0.25 ppm, 0.01 ppm to 0.25 ppm), more preferably 0.20 ppm or less (e.g., less than 0.20 ppm, 0.01 ppm to 0.20 ppm), particularly preferably 0.15 ppm or less (e.g., less than 0.15 ppm, 0.01 ppm to 0.15 ppm), and most preferably 0.10 ppm or less (e.g., less than 0.10 ppm, 0.01 ppm to 0.10 ppm).

[0178] The haze can be measured by the method described in the Examples below.

[0179] The polished surface of the object was measured using an atomic force microscope with a field of view of 30 × 30 μm. 2The root mean square height (Sq) measured by the method described above is preferably less than 0.030 nm, and more preferably less than 0.028 nm.

[0180] The lower limit of the root mean square height (Sq) is not particularly limited, and may be, for example, 0.005 nm or more, or 0.01 nm or more.

[0181] The root mean square height (Sq) can be measured by the method described in the Examples below.

[0182] An article to be polished having the above-described polished surface can be obtained, for example, by polishing and cleaning an object to be polished with a polishing composition containing a water-soluble polymer. The water-soluble polymer may be, for example, one having a long side chain (e.g., one having a side chain group with 3 or more carbon atoms (e.g., one having a side chain group with 3 or more carbon atoms exemplified in the vinyl alcohol-based resin (A))), one having a low viscosity (e.g., one having a viscosity of 300 mPa·s or less in a 4% aqueous solution at 20°C), or the like. As the water-soluble polymer, for example, a vinyl alcohol resin can be suitably used, and by using the vinyl alcohol resin (A) or (B), it is easy to efficiently obtain a polished object having the above-mentioned polished surface.

[0183] Furthermore, the water-soluble polymer may be one that has little of the properties that are thought to affect the occurrence of minute defects (for example, aggregation, separation, thickening, gelation, etc.). The water-soluble polymer may also be one that contains few coarse components and one that contains little metal impurities (for example, Ni, Cu, etc.). Such water-soluble polymers may be obtained, for example, by filtration or ion exchange treatment. [Example]

[0184] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" refer to "parts by mass" and "% by mass" unless otherwise specified.

[0185] The physical properties in the examples were evaluated by the following methods.

[0186] (1) Residual diacetone acrylamide: CDCl3 as solvent 1 H-NMR was measured, and the values ​​were calculated from the integrals of the assigned peaks.

[0187] (2) Vinyl acetate residue: CDCl3 as solvent 1 H-NMR was measured, and the values ​​were calculated from the integrals of the assigned peaks.

[0188] (3) Hexadecyl vinyl ether residue: CDCl3 as solvent 1 H-NMR was measured, and the values ​​were calculated from the integrals of the assigned peaks.

[0189] (4) Polymerization yield: Each polymer paste is completely dried and the solid content concentration is measured. The polymerization yield is the product of the yield coefficient calculated by the following formula and the solid content concentration. In addition, if diacetone acrylamide or hexadecyl vinyl ether remains in the solid content, it is 1 H-NMR was measured, and the residual amount was calculated from the integrated value of the assigned peak, and the value obtained by subtracting this from the solid content concentration was used. Yield coefficient = total charge amount / total charge amount of monomers The total amount charged in the above formula refers to the total amount of components charged into the reaction system for carrying out polymerization, such as monomers, solvents, and initiators.

[0190] (5) Viscosity of 4% aqueous solution: Measured according to JIS K 6726 (1994).

[0191] (6) Saponification degree: Measured according to JIS K 6726 (1994).

[0192] (7) Diacetone acrylamide unit content: DMSO-d6 as solvent 1 H-NMR measurements were performed, and the values ​​were calculated from the integrals of the assigned peaks.

[0193] (8) Hexadecyl vinyl ether unit content: DMSO-d6 as solvent 1 H-NMR measurements were performed, and the values ​​were calculated from the integrals of the assigned peaks.

[0194] (Water-soluble polymer) (Synthesis Example 1) A flask equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 2,000 parts vinyl acetate, 604 parts methanol, and 8.2 parts diacetone acrylamide (DAAM). The system was purged with nitrogen and then heated to 60°C. After heating, a solution of 1.2 parts 2,2-azobisisobutyronitrile in 100 parts methanol was added to initiate polymerization. While continuing to circulate nitrogen through the flask, a solution of 127.8 parts diacetone acrylamide in 80 parts methanol was added dropwise at a constant rate immediately after the start of polymerization. At the end of the polymerization, m-dinitrobenzene was added as a polymerization terminator to terminate the polymerization. The yield at the end of the polymerization was 73.8%. Methanol vapor was added to the resulting reaction mixture to distill off the remaining vinyl acetate, yielding a 50% methanol solution of diacetone acrylamide-vinyl acetate copolymer. 70 parts of methanol, 2 parts of ion-exchanged water, and 15 parts of a 4% methanol solution of sodium hydroxide were added to 500 parts of this solution and mixed thoroughly, followed by saponification at 45°C. The resulting gel was crushed, thoroughly washed with methanol, and dried to yield a PVA-based resin (DA-PVA1). The viscosity of a 4% aqueous solution of the resulting DA-PVA1 was 20.5 mPa·s, and the degree of saponification was 98.6 mol%. The diacetone unit content in DA-PVA1 was 4.6 mol%.

[0195] (Synthesis Examples 2 to 7) DA-PVA2 to DA-PVA7 shown in Table 1 or Table 2 were obtained in the same manner as in Synthesis Example 1, except that the charge blending ratio and saponification conditions during polymerization were changed so as to obtain PVA-based resins with the modification degrees and saponification degrees shown in Table 1 or Table 2.

[0196] (Synthesis Example 8) A flask equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 2,000 parts vinyl acetate, 781.7 parts methanol, and 12.5 parts hexadecyl vinyl ether (HDVE). After the system was purged with nitrogen, the internal temperature was raised to 60°C. After the temperature was raised, a solution of 1.6 parts 2,2-azobisisobutyronitrile in 100 parts methanol was added to initiate polymerization. While continuing to circulate nitrogen through the flask, a solution of 141.1 parts diacetone acrylamide in 80 parts methanol was added dropwise at a constant rate immediately after the initiation of polymerization. At the end of the polymerization, m-dinitrobenzene was added as a polymerization terminator to terminate the polymerization. The polymerization yield was 87.7%. Methanol vapor was added to the resulting reaction mixture while distilling off the remaining vinyl acetate and hexadecyl vinyl ether, yielding a 53% methanol solution of diacetone acrylamide-hexadecyl vinyl ether-vinyl acetate copolymer. 70 parts of methanol, 2 parts of ion-exchanged water, and 15 parts of a 4% methanol solution of sodium hydroxide were added to 500 parts of this solution and mixed thoroughly, allowing the saponification reaction to proceed at 45°C. The resulting gel-like substance was crushed, thoroughly washed with methanol, and then dried to yield the PVA resin (DAHD-PVA) listed in Table 1.

[0197] (Synthesis Examples 9 to 18) In accordance with the method described in Production Example 1 of JP 2013-153149 A, the polymerization conditions (e.g., charge blend ratio during polymerization, temperature, pressure, polymerization time) and saponification conditions (e.g., temperature and time during saponification) were changed so as to obtain PVAs with 4% viscosities and saponification degrees shown in Tables 1 and 4 (PVA-3 had a 4% aqueous solution viscosity of 226.1 mPa s and a saponification degree of 99.3 mol%). PVA-1 to PVA-2, PVA-6, and PVA-3 shown in Table 1 and PVA-8 to PVA-13 shown in Table 4 were obtained.

[0198] Example 1 A colloidal silica dispersion was prepared by adding aqueous ammonia containing 29% ammonia (NH3) as a basic compound to an aqueous solution containing 1% colloidal silica with an average primary particle size of 35 nm as abrasive grains, and adjusting the pH to 10.0. The DA-PVA1 was added to this colloidal silica dispersion to a concentration of 100 ppm based on the total amount of the solution, to obtain a composition (polishing liquid). The silica content in the composition was 1%.

[0199] Examples 2 to 7 Compositions were obtained in the same manner as in Example 1, except that the water-soluble polymers listed in Table 1 were used, and in the examples indicated as EOPO, a copolymer having an EO-PO structure (polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid.

[0200] (Examples 8 to 9) Compositions were obtained in the same manner as in Example 1, except that the water-soluble polymers listed in Table 1 were used, and in the examples indicated as EOPO, a copolymer having an EO-PO structure (polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid.

[0201] (Examples 18 to 19) Compositions were obtained in the same manner as in Example 1, except that the water-soluble polymers listed in Table 1 were used, and in the examples indicated as EOPO, a copolymer having an EO-PO structure (polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid.

[0202] Example 20 A composition was obtained in the same manner as in Example 1, except that PVA-7 obtained by mixing PVA-3 and PVA-5 in a PVA-3:PVA-5 (mass ratio) of 82:18 was used.

[0203] (Comparative Example 1) A composition was obtained in the same manner as in Example 1, except that hydroxyethyl cellulose (Hydroxyethyl Cellulose SE400, manufactured by Daicel Finechem) was used as the water-soluble polymer.

[0204] (Comparative Example 2) A composition was obtained in the same manner as in Example 1, except that hydroxyethyl cellulose (Hydroxyethyl Cellulose SE400, manufactured by Daicel FineChem) was used as the water-soluble polymer, and a copolymer having an EO-PO structure (Polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid.

[0205] (Comparative Example 3) A composition was obtained in the same manner as in Example 1, except that polyvinylpyrrolidone (Polyvinylpyrrolidone K90, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the water-soluble polymer.

[0206] (Reference examples 1~3) Compositions were obtained in the same manner as in Example 1, except that the water-soluble polymers listed in Table 1 were used, and in the examples indicated as EOPO, a copolymer having an EO-PO structure (polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid. The water-soluble polymers used in Table 1 were as follows: PVA-4: JMR-800HH manufactured by Nippon Vinyl Acetate & Poval Co., Ltd. PVA-5: JMR-500HH manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.

[0207] <Silicon wafer polishing> The surface of a silicon wafer was polished using the polishing liquid according to each example under the following conditions. The silicon wafer is 300 mm in diameter, P-type, and oriented <100> A single crystal silicon wafer with a resistivity of 0.1 Ω·cm or more and less than 100 Ω·cm was used.

[0208] The polishing evaluation was carried out using a sheet-fed polishing machine, model "PNX-332B," manufactured by Okamoto Machine Tool Works, Ltd., in two stages: preliminary polishing to standardize the condition of the front surface, and finish polishing using the above composition. [Preliminary polishing conditions] Polishing cloth: non-woven fabric Polishing solution: Colloidal silica solution adjusted to pH 11 with KOH Polishing load: 30kPa Plate rotation speed: 50 rpm Head rotation speed: 50 rpm Polishing time: 3 minutes [Finishing polishing conditions] Polishing cloth: suede Polishing load: 15kPa Plate rotation speed: 30 rpm Head rotation speed: 30 rpm Polishing time: 3 minutes

[0209] <Cleaning> The polished silicon wafer was washed with a mixture (SC1) of NH4OH, H2O2, and ultrapure water (volume ratio of NH4OH:H2O2:ultrapure water was 1:3:30).

[0210] <Micro-defect inspection> (Number of LLS defects 26nm or larger) The surface of the cleaned silicon wafer was inspected for the number of LLS defects of 26 nm or more per 300 mm diameter using a wafer defect inspection system manufactured by KLA-Tencor, product name "SP3." The results were evaluated using the following four levels. The number of LLS defects was measured excluding a 3 mm outer periphery of the surface of the 300 mm diameter silicon wafer. A: 100 or fewer detections B: Detection count: over 100 and up to 300 C: Detection count: over 300 and under 700 D: Number of detections exceeds 700

[0211] (Number of LLS defects of 19 nm or more) The surface of the silicon wafer after cleaning was inspected for the number of LLS defects of 19 nm or more per 300 mm in diameter using a wafer defect inspection device manufactured by KLA Tencor, trade name "SP5". The results were evaluated in the following four levels. The number of LLS defects was measured excluding the outer 3 mm of the surface of the 300 mm diameter silicon wafer. A: Number of detections is 250 or less B: Number of detections exceeds 250 and is 550 or less C: Number of detections exceeds 550 and is 850 or less D: Number of detections exceeds 850

[0212] <Haze measurement> The haze (ppm) was measured in the DWO mode on the surface of the silicon wafer after cleaning using a wafer inspection device manufactured by KLA Tencor, trade name "SP3". The measurement results were evaluated in the following four levels. A: Less than 0.10 ppm B: 0.10 ppm or more and less than 0.20 ppm [[ID=​​​​​​​​​​​​​​​​​​The evaluation results for Examples 1 to 9, Examples 18 to 20, Comparative Examples 1 to 3, and Reference Examples 1 to 3 are shown in Table 1.

[0215] [Table 1]

[0216] As shown in Table 1, in Examples 1 to 9 and 18 to 20, the number of LLS defects of 26 nm or more was reduced. Furthermore, in Examples 1 to 9 and 18 to 20, the haze was small. Furthermore, in Examples 1 to 9 and 18 to 20, the AFM roughness was small.

[0217] (Examples 10 to 17) Compositions were obtained in the same manner as in Example 1, except that the water-soluble polymers listed in Table 2 were used, and in the cases indicated as EOPO, a copolymer having an EO-PO structure (polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid. The evaluation results are shown in Table 2.

[0218] Table 3 also shows the evaluation results for the number of LLS defects of 19 nm or more for Examples 1 to 5.

[0219] [Table 2]

[0220] [Table 3]

[0221] As shown in Tables 2 and 3, in Examples 1 to 5 and 10 to 17, the number of LLS defects of 19 nm or more was reduced. Furthermore, as shown in Table 2, Examples 10 to 17 had low haze. Furthermore, in Examples 10 to 17, the AFM roughness was small.

[0222] Examples 21 to 30 A composition was obtained in the same manner as in Example 1, except that a colloidal silica dispersion liquid having a pH of 7.2 and containing colloidal silica with an average primary particle size of 35 nm at a concentration of 1% was used as the abrasive grains, and a water-soluble polymer listed in Table 4 was used. In the examples where EOPO is mentioned, a copolymer having an EO-PO structure was added in the same manner as above.

[0223] Comparative Example 4 A composition was obtained in the same manner as in Example 21, except that hydroxyethyl cellulose (Daicel Finechem, Hydroxyethyl Cellulose SE400) was used as the water-soluble polymer.

[0224] (Comparative Example 5) A composition was obtained in the same manner as in Example 21, except that hydroxyethyl cellulose (Hydroxyethyl Cellulose SE400, manufactured by Daicel FineChem) was used as the water-soluble polymer, and a copolymer having an EO-PO structure (Polyoxyethylene polyoxypropylene glycol (160 E.O.) (30 P.O.) manufactured by Wako Pure Chemical Industries, Ltd.) was added to the colloidal silica dispersion so that the content was 10 ppm based on the total amount of the liquid.

[0225] The evaluation results for Examples 21 to 30 and Comparative Examples 4 and 5 are shown in Table 4.

[0226] [Table 4]

[0227] As shown in Table 4, in Examples 21 to 30, the number of LLS defects of 26 nm or more was reduced. Furthermore, in Examples 21 to 30, the haze was small. Furthermore, in Examples 21 to 30, the AFM roughness was small. [Industrial Applicability]

[0228] The composition of the present invention can reduce LLS defects in the object to be polished, and therefore can efficiently process substrates having a protective film formed on the surface, making it extremely useful industrially.

Claims

[Claim 1] The invention described herein.

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