Polishing composition, concentrated solution of polishing composition, and polishing method

Abstract

To provide means for improving the surface quality of a workpiece after polishing.SOLUTION: A polishing composition used for polishing a surface made of silicon material includes abrasive grains, a basic compound, a polyvinyl alcohol polymer, and a polyhydric alcohol having a molecular weight of 600 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polishing composition, a concentrated polishing composition, and a polishing method. [Background technology]

[0002] In order to realize high integration and high speed of integrated circuits such as ULSI used in computers, design rules for semiconductor devices are becoming finer year by year. As a result, there are more and more cases where even minute surface defects have a negative effect on the performance of semiconductor devices, and the importance of managing nano-order defects that were not considered a problem in the past is increasing.

[0003] For example, Patent Document 1 discloses a polishing composition for wafers that contains water, silica particles, an alkali compound, polyvinyl alcohol, anion-modified polyvinyl alcohol, and a surfactant, and the mass ratio of the anion-modified polyvinyl alcohol to the polyvinyl alcohol is 0.6 to 5.5. This technology is said to be capable of improving the haze of wafers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6028942 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique described in Patent Document 1 does not sufficiently improve the surface quality of the object after polishing, and further improvement is required.

[0006] Therefore, an object of the present invention is to provide a means capable of improving the surface quality of an object to be polished after polishing. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research and have found that the above problems can be solved by a polishing composition used for polishing a surface made of a silicon material, the polishing composition comprising an abrasive grain, a basic compound, a polyvinyl alcohol-based polymer, and a polyhydric alcohol having a molecular weight of 600 or less, and have completed the present invention. Effect of the Invention

[0008] According to the present invention, there is provided a means capable of improving the surface quality of an object to be polished after polishing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention relates to a polishing composition used for polishing the surface of a silicon material, the polishing composition comprising abrasive grains, a basic compound, a polyvinyl alcohol-based polymer, and a polyhydric alcohol having a molecular weight of not more than 600. The polishing composition according to one embodiment of the present invention having such a configuration can improve the surface quality of an object to be polished after polishing.

[0010] The mechanism by which the polishing composition of the present invention provides the above-mentioned effects is believed to be as follows: However, the following mechanism is merely speculation, and the scope of the present invention is not limited thereto.

[0011] On the surface of the object to be polished after polishing, there are organic residues derived from abrasive grains, polishing pads, etc., and removing these residues as much as possible leads to improvement of surface quality. The polyhydric alcohol with a molecular weight of 600 or less used in the present invention is easily adsorbed to the above-mentioned surface of the object to be polished and the residues, but can be easily removed when cleaning the surface of the object to be polished after polishing. Therefore, it is considered that the residues on the surface of the object to be polished after polishing are removed together with the polyhydric alcohol, and thus the surface quality of the object to be polished after polishing can be improved.

[0012] Hereinafter, the embodiments of the present invention will be described, but the present invention is not limited to the following embodiments and can be modified in various ways within the scope of the claims. The embodiments described in this specification can be arbitrarily combined to form other embodiments.

[0013] In this specification, unless otherwise specified, operations and measurements of physical properties are performed under conditions of room temperature (20° C. or higher and 25° C. or lower) and relative humidity of 40% RH or higher and 50% RH or lower.

[0014] [Abrasive grain] The polishing composition according to some embodiments of the present invention includes abrasive grains. The abrasive grains function to mechanically polish the surface of the object to be polished. The material and properties of the abrasive grains are not particularly limited, and can be appropriately selected according to the purpose and mode of use of the polishing composition. Examples of the abrasive grains include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include particles made of oxides such as silica, alumina, cerium oxide, chromium oxide, titanium dioxide, zirconium oxide, magnesium oxide, manganese dioxide, zinc oxide, and red iron oxide; particles made of nitrides such as silicon nitride and boron nitride particles; particles made of carbides such as silicon carbide and boron carbide; particles made of diamond; carbonates such as calcium carbonate and barium carbonate, and the like. Specific examples of organic particles include polymethylmethacrylate (PMMA) particles, poly(meth)acrylic acid particles (here, (meth)acrylic acid refers collectively to acrylic acid and methacrylic acid), polyacrylonitrile particles, and the like. Such abrasive grains may be used alone or in combination of two or more kinds.

[0015] The polishing composition according to some embodiments of the present invention preferably contains silica as an abrasive. Specific examples of silica include colloidal silica, fumed silica, precipitated silica, and the like. Silica can be used alone or in combination of two or more. Colloidal silica is particularly preferred because it is less likely to cause scratches on the surface of the object to be polished and can exhibit good polishing performance (performance of reducing surface roughness, etc.). As colloidal silica, for example, colloidal silica produced by the ion exchange method using water glass (Na silicate) as a raw material, or colloidal silica produced by the alkoxide method (colloidal silica produced by hydrolysis and condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used alone or in combination of two or more.

[0016] The true specific gravity of silica is preferably 1.5 or more, more preferably 1.6 or more, and even more preferably 1.7 or more. The upper limit of the true specific gravity of silica is not particularly limited, but is typically 2.3 or less, for example, 2.2 or less. The true specific gravity of silica can be measured by a liquid substitution method using ethanol as a substitution liquid.

[0017] The shape of colloidal silica is not particularly limited, and may be spherical or non-spherical.Specific examples of non-spherical shapes include polygonal prisms such as triangular prisms and square prisms, cylinders, bales in which the center of a cylinder is bulging out more than the ends, donuts in which the center of a disk is penetrated, plates, so-called cocoons with a constriction in the center, so-called association-type spheres in which multiple particles are integrated, so-called confetti-shaped shapes with multiple protrusions on the surface, and rugby ball shapes, and are not particularly limited.

[0018] Although not particularly limited, the average value of the long diameter / short diameter ratio (average aspect ratio) of the abrasive grain is in principle 1.0 or more, preferably 1.05 or more, and more preferably 1.1 or more. By increasing the average aspect ratio, a higher polishing rate can be realized. In addition, from the viewpoint of reducing scratches, etc., the average aspect ratio of the abrasive grain is preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.5 or less.

[0019] The shape (outer shape) and average aspect ratio of the abrasive grains can be grasped, for example, by observation with an electron microscope. As a specific procedure for grasping the average aspect ratio, for example, a scanning electron microscope (SEM) is used to draw the smallest rectangle circumscribing each particle image for a predetermined number (for example, 200) of silica particles whose individual particle shapes can be recognized. Then, for the rectangle drawn for each particle image, the value obtained by dividing the length of the long side (value of the long axis) by the length of the short side (value of the short axis) is calculated as the long axis / short axis ratio (aspect ratio). The average aspect ratio can be obtained by arithmetically averaging the aspect ratios of the above-mentioned predetermined number of particles.

[0020] The abrasive grains contained in the polishing composition may be in the form of primary particles, or may be in the form of secondary particles in which a plurality of primary particles are associated. In addition, the abrasive grains in the form of primary particles and the abrasive grains in the form of secondary particles may be mixed. In a preferred embodiment, at least a part of the abrasive grains are contained in the polishing composition in the form of secondary particles.

[0021] Here, the surface of the object to be polished (particularly silicon wafer) is generally finished to a high-quality mirror surface through a lapping process and a polishing process. The polishing process is usually composed of a plurality of polishing processes including a preliminary polishing process (preliminary polishing process, a polishing process before the final polishing process) and a final polishing process (final polishing process). For example, a polishing composition with high processing power (polishing power) is used in the stage (e.g., preliminary polishing process) where the object to be polished (particularly silicon wafer) is roughly polished, and a polishing composition with low polishing power is used in the stage (e.g., final polishing process) where the object to be polished is more delicately polished. Thus, the polishing composition used has different polishing characteristics required for each polishing process, so that the particle size and content of silica contained in the polishing composition can be different depending on the stage of the polishing process where the polishing composition is used.

[0022] In this case, an increase in the particle size of the abrasive grains tends to facilitate mechanical polishing of the surface of the object to be polished, and tends to improve the polishing rate, whereas a decrease in the particle size of the abrasive grains tends to facilitate reduction in haze of the polished object.

[0023] The average primary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and particularly preferably 20 nm or more (e.g., more than 20 nm). The average primary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is, for example, 100 nm or less, may be 80 nm or less, preferably 60 nm or less, more preferably 50 nm or less, even more preferably 45 nm or less, and particularly preferably 43 nm or less. In some embodiments, the average primary particle size of the abrasive grains may be less than 40 nm, may be less than 38 nm, may be less than 35 nm, may be less than 32 nm, or may be less than 30 nm.

[0024] The average secondary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is preferably 10 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, and particularly preferably 35 nm or more. In some embodiments, the average secondary particle size of the abrasive grains may be 40 nm or more, 42 nm or more, or 44 nm or more. In addition, the average secondary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is, for example, 250 nm or less, 180 nm or less, 150 nm or less, preferably 100 nm or less, more preferably 90 nm or less, and even more preferably 80 nm or less. In some embodiments, the average secondary particle size of the abrasive grains may be 70 nm or less, 60 nm or less, or 50 nm or less.

[0025] The preferred ranges of the average primary particle size and average secondary particle size of the abrasive grains described above are also the preferred ranges of the average primary particle size and average secondary particle size of the abrasive grains contained in the raw material dispersion liquid used in the preparation thereof.

[0026] In this specification, the average primary particle size is calculated by the following formula: average primary particle size (nm) = 6000 / (true density (g / cm)) based on the specific surface area (BET value) measured by the BET method. 3 ) × BET value (m 2 The specific surface area refers to the particle size (BET particle size) calculated by the formula: specific surface area = specific surface area (μm / g). The specific surface area can be measured, for example, using a "Flow SorbII 2300" manufactured by Micromeritics. The average secondary particle size of the abrasive grains is measured, for example, by dynamic light scattering, for example, using a "Nanotrack (registered trademark) UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0027] Furthermore, as described above, since the polishing properties required for the polishing composition used differ for each polishing process, the content of abrasive grains in the polishing composition can also differ depending on the stage of the polishing process at which the polishing composition is used.

[0028] In this case, an increase in the content of abrasive grains tends to improve the polishing rate for the surface of the object to be polished, while a decrease in the content of abrasive grains tends to improve the dispersion stability of the polishing composition and reduce the amount of abrasive grain residue on the polished surface.

[0029] When the polishing composition according to some embodiments of the present invention is in the state of a concentrated liquid that is diluted with a dispersion medium or the like and used for polishing, the concentration (content) of abrasive grains is not particularly limited, but is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, more preferably 0.025 mass% or more, even more preferably 0.1 mass% or more, particularly preferably 0.5 mass% or more, even more particularly preferably 1 mass% or more, and most preferably 3 mass% or more, based on the total mass of the polishing composition.In addition, in this case, the concentration (content) of abrasive grains is not particularly limited, but is preferably 50 mass% or less, more preferably 20 mass% or less, more preferably 10 mass% or less, and particularly preferably 9 mass% or less, based on the total mass of the polishing composition, based on storage stability, filterability, etc.

[0030] In addition, when the polishing composition according to some embodiments of the present invention is in the state of a diluted solution, the concentration (content) of the abrasive grains is not particularly limited, but from the viewpoint of further improving the polishing rate, it is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, even more preferably 0.025 mass% or more, and particularly preferably 0.1 mass% or more, based on the total mass of the polishing composition.In addition, in this case, the concentration (content) of the abrasive grains in the polishing composition is not particularly limited, but, for example, based on the total mass of the polishing composition, it may be less than 10 mass%, may be less than 7 mass%, may be 5 mass% or less, may be 2 mass% or less, preferably less than 1 mass%, more preferably 0.8 mass% or less, more preferably 0.6 mass% or less, particularly preferably 0.4 mass% or less, and most preferably 0.3 mass% or less.

[0031] When two or more types of abrasive grains are used, the above concentration (content) refers to the total amount.

[0032] When the above-mentioned polishing composition is used as a diluted solution, the preferred abrasive grain content is preferably adjusted by diluting a concentrated solution of the polishing composition with a dispersion medium such as water, or a solution or dispersion containing an optional polishing aid therein.

[0033] The polishing composition according to some embodiments of the present invention may contain colloidal silica and other abrasive grains than colloidal silica. However, when the polishing composition according to some embodiments of the present invention is in a diluted state, the content of the other abrasive grains is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the colloidal silica and the other abrasive grains. The most preferred embodiment is one in which the content of the other abrasive grains is 0% by mass, that is, one in which no abrasive grains other than colloidal silica are contained.

[0034] [Basic compounds] The polishing composition according to the present invention contains a basic compound. The basic compound refers to a compound that has the function of increasing the pH of water when added to water.

[0035] The type of basic compound is not particularly limited, and examples thereof include organic or inorganic basic compounds containing nitrogen, hydroxides of alkali metals or alkaline earth metals (group 2 metals), various carbonates and hydrogen carbonates, quaternary ammonium hydroxides or their salts, ammonia, amines, etc. Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of alkaline earth metal hydroxides include calcium hydroxide, strontium hydroxide, barium hydroxide, etc. Specific examples of carbonates or hydrogen carbonates include ammonium hydrogen carbonate, ammonium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, sodium carbonate, etc. Specific examples of quaternary ammonium hydroxides or their salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole.

[0036] From the viewpoint of reducing surface defects, the basic compound is preferably at least one selected from the group consisting of ammonia, quaternary ammonium hydroxide, salts of quaternary ammonium hydroxide, carbonates, hydrogen carbonates, and hydroxides of alkali metals. Among these, at least one selected from the group consisting of ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, potassium hydroxide, and sodium hydroxide is more preferable, at least one selected from the group consisting of ammonia and tetramethylammonium hydroxide is even more preferable, and ammonia is particularly preferable. The basic compound can be used alone or in combination of two or more. In addition, the basic compound can be used as a commercially available product or a synthetic product.

[0037] When the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid that is diluted with a dispersion medium or the like and used for polishing, the concentration (content) of the basic compound in the polishing composition is not particularly limited, but is preferably 0.001 mass% or more, more preferably 0.005 mass% or more, even more preferably 0.01 mass% or more, and particularly preferably 0.05 mass% or more, based on the total mass of the polishing composition.In addition, in this case, the concentration (content) of the basic compound in the polishing composition is not particularly limited, but is preferably 45 mass% or less, more preferably 15 mass% or less, even more preferably 5 mass% or less, and particularly preferably 1 mass% or less, based on the total mass of the polishing composition, from the viewpoint of storage stability, etc. That is, when the polishing composition is in the form of a concentrated liquid, the concentration (content) of the basic compound, relative to the total mass of the polishing composition, is preferably 0.001 mass% or more and 45 mass% or less, more preferably 0.005 mass% or more and 15 mass% or less, even more preferably 0.01 mass% or more and 5 mass% or less, and particularly preferably 0.05 mass% or more and 1 mass% or less.

[0038] When the polishing composition according to some embodiments of the present invention is in the state of a diluted solution, the concentration (content) of the basic compound in the polishing composition is not particularly limited, but from the viewpoint of improving the polishing removal rate, etc., it is preferably 0.0001 mass% or more, more preferably 0.0005 mass% or more, even more preferably 0.001 mass% or more, even more preferably 0.002 mass% or more, and particularly preferably 0.003 mass% or more, based on the total mass of the polishing composition. In addition, in this case, the concentration (content) of the basic compound in the polishing composition is preferably 15 mass% or less, more preferably 10 mass% or less, even more preferably 5 mass% or less, even more preferably 1 mass% or less, and particularly preferably 0.5 mass% or less, based on the total mass of the polishing composition, based on the viewpoint of improving surface quality, such as reducing defects. That is, when the polishing composition is in the form of a diluted solution, the concentration (content) of the basic compound is preferably 0.0001 mass% or more and 15 mass% or less, more preferably 0.0005 mass% or more and 10 mass% or less, even more preferably 0.001 mass% or more and 5 mass% or less, even more preferably 0.002 mass% or more and 1 mass% or less, and particularly preferably 0.003 mass% or more and 0.5 mass% or less, relative to the total mass of the polishing composition.

[0039] When two or more kinds of basic compounds are used, the above concentration (content) refers to the total amount thereof.

[0040] [Polyvinyl alcohol polymer] The polyvinyl alcohol-based polymer may contain only vinyl alcohol units (hereinafter also referred to as "VA units") as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units"). The vinyl alcohol unit is represented by the following chemical formula: -CH 2A structural portion represented by -CH(OH)-;. The polyvinyl alcohol-based polymer may be a random copolymer containing VA units and non-VA units, or may be a block copolymer, a graft copolymer, or an alternating copolymer. The polyvinyl alcohol-based polymer may contain only one type of non-VA unit, or may contain two or more types of non-VA units. In this specification, all water-soluble polymers having VA units are classified as polyvinyl alcohol-based polymers.

[0041] The polyvinyl alcohol-based polymer used in the polishing composition disclosed herein may be unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA). Here, unmodified PVA is a PVA produced by hydrolysis (saponification) of polyvinyl acetate, and has a repeating unit (-CH 2 -CH(OCOCH 3 )-) and a polyvinyl alcohol-based polymer that does not substantially contain repeating units other than VA units. The degree of saponification of the non-modified PVA may be, for example, 60% or more, and from the viewpoint of water solubility, may be 70% or more, 80% or more, or 90% or more. In some embodiments, a non-modified PVA having a degree of saponification of 95% or more or 98% or more may be preferably used as the water-soluble polymer compound.

[0042] The polyvinyl alcohol-based polymer may be a modified PVA containing VA units and non-VA units having at least one structure selected from an oxyalkylene group, a carboxy group, a (di)carboxylic acid group, a (di)carboxylic acid ester group, a phenyl group, a naphthyl group, a sulfo group, an amino group, a hydroxy group, an amide group, an imide group, a nitrile group, an ether group, an ester group, and salts thereof.

[0043] Non-VA units that may be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl monomers or N-(meth)acryloyl monomers described below, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, and repeating units derived from (di)acetone compounds. A suitable example of the N-vinyl monomer is N-vinylpyrrolidone. A suitable example of the N-(meth)acryloyl monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate. Suitable examples of the (di)acetone compound include diacetone (meth)acrylamide and acetylacetone.

[0044] The polyvinyl alcohol-based polymer may be a modified PVA in which a part of the VA units contained in the polyvinyl alcohol-based polymer is acetalized with an aldehyde compound or a ketone compound. In a preferred embodiment of the technology disclosed herein, the acetalized modified PVA is a water-soluble polymer obtained by an acetalization reaction between the above-mentioned non-modified PVA and an aldehyde compound.

[0045] In one embodiment of the present invention, the aldehyde compound used to produce the acetalized modified PVA is not particularly limited. In a preferred embodiment, the aldehyde compound has 1 to 7 carbon atoms, more preferably 2 to 7 carbon atoms.

[0046] Examples of the aldehyde compound include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde, tert-butylaldehyde, hexylaldehyde, and n-pentylaldehyde; and alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde. These may be used alone or in combination of two or more. In addition, except for formaldehyde, one or more hydrogen atoms may be substituted with halogen or the like. Among them, linear or branched alkyl aldehydes are preferred from the viewpoint of high solubility in water and easy acetalization reaction, and among them, acetaldehyde, propionaldehyde, n-butylaldehyde, and n-pentylaldehyde are more preferred.

[0047] In addition to the above, aldehyde compounds having 8 or more carbon atoms, such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde, may be used as the aldehyde compound. In addition, as the polyvinyl alcohol-based polymer, a cation-modified polyvinyl alcohol into which a cationic group such as a quaternary ammonium structure has been introduced may be used. As the cation-modified polyvinyl alcohol, for example, one into which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, has been introduced may be used. In addition, as the polyvinyl alcohol-based polymer, a cation-modified polyvinyl alcohol into which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, ... has been introduced may be used. 2 -CH(CR 1 (OR 4 )-CR 2 (OR 5 )-R 3 )-, where R 1 ~R 3 each independently represents a hydrogen atom or an organic group; R 4 and R 5 are each independently a hydrogen atom or R 6 -CO-(wherein, R 6represents an alkyl group. For example, R in the above chemical formula 1 ~R 3 When at least one of R is an organic group, the organic group may be a linear or branched alkyl group having 1 to 8 carbon atoms. 6 can be a straight or branched chain alkyl group having from 1 to 8 carbon atoms.

[0048] In some embodiments, a modified PVA having a 1,2-diol structure in a side chain is used as the polyvinyl alcohol-based polymer. 1 ~R 5 Examples of polymers that contain non-VA units where the valence atom is a hydrogen atom include butenediol-vinyl alcohol copolymer (BVOH).

[0049] The ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. Although not particularly limited, in some embodiments, the ratio of the number of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (for example, 95% or more, or 98% or more). Substantially 100% of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100%" means that the polyvinyl alcohol-based polymer does not contain non-VA units at least intentionally, and typically the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (for example, less than 1%), including the case of 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0050] The content of VA units in the polyvinyl alcohol-based polymer (content based on mass) may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more. Although not particularly limited, in some embodiments, the content of the VA units may be 50% by mass or more (e.g., more than 50% by mass), 70% by mass or more, or 80% by mass or more (e.g., 90% by mass or more, 95% by mass or more, or 98% by mass or more). Substantially 100% by mass of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100% by mass" means that non-VA units are not contained as repeating units constituting the polyvinyl alcohol-based polymer at least intentionally, and typically means that the content of non-VA units in the polyvinyl alcohol-based polymer is less than 2% by mass (e.g., less than 1% by mass). In some other embodiments, the content of VA units in the polyvinyl alcohol-based polymer may be, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[0051] A polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit contents in the same molecule. Here, the polymer chain refers to a portion (segment) that constitutes a part of a single polymer molecule. For example, a polyvinyl alcohol-based polymer may contain a polymer chain A with a VA unit content of more than 50% by mass and a polymer chain B with a VA unit content of less than 50% by mass (i.e., a non-VA unit content of more than 50% by mass) in the same molecule.

[0052] The polymer chain A may contain only VA units as repeat units, or may contain non-VA units in addition to VA units. The content of VA units in the polymer chain A may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the content of VA units in the polymer chain A may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeat units constituting the polymer chain A may be VA units.

[0053] The polymer chain B may contain only non-VA units as repeat units, or may contain VA units in addition to non-VA units. The content of non-VA units in the polymer chain B may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of non-VA units in the polymer chain B may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeat units constituting the polymer chain B may be non-VA units.

[0054] Examples of polyvinyl alcohol-based polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The graft copolymer may be a graft copolymer having a structure in which polymer chain B (side chain) is grafted to polymer chain A (main chain), or a graft copolymer having a structure in which polymer chain A (side chain) is grafted to polymer chain B (main chain). In one embodiment, a polyvinyl alcohol-based polymer having a structure in which polymer chain B is grafted to polymer chain A can be used.

[0055] Examples of the polymer chain B include a polymer chain having a repeating unit derived from an N-vinyl type monomer as the main repeating unit, a polymer chain having a repeating unit derived from an N-(meth)acryloyl type monomer as the main repeating unit, a polymer chain having a repeating unit derived from a vinyl dicarboxylate such as fumaric acid, maleic acid, or maleic anhydride as the main repeating unit, a polymer chain having a repeating unit derived from an aromatic vinyl monomer such as styrene or vinylnaphthalene as the main repeating unit, a polymer chain having an oxyalkylene unit as the main repeating unit, etc. In this specification, the main repeating unit refers to a repeating unit contained in an amount of more than 50% by weight, unless otherwise specified.

[0056] A preferred example of the polymer chain B is a polymer chain having an N-vinyl type monomer as a main repeating unit, i.e., an N-vinyl polymer chain. The content of the repeating unit derived from the N-vinyl type monomer in the N-vinyl polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of the polymer chain B may be a repeating unit derived from an N-vinyl type monomer.

[0057] Examples of N-vinyl type monomers include monomers having a nitrogen-containing heterocycle (e.g., lactam ring) and N-vinyl chain amides. Specific examples of N-vinyl lactam type monomers include N-vinyl pyrrolidone, N-vinyl piperidone, N-vinyl morpholinone, N-vinyl caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, and the like. Specific examples of N-vinyl chain amides include N-vinyl acetamide, N-vinyl propionic acid amide, N-vinyl butyric acid amide, and the like. The polymer chain B may be, for example, an N-vinyl polymer chain in which more than 50% by mass (e.g., 70% by mass or more, 85% by mass or more, or 95% by mass or more) of its repeating units are N-vinyl pyrrolidone units. Substantially all of the repeating units constituting the polymer chain B may be N-vinyl pyrrolidone units.

[0058] Other examples of the polymer chain B include a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer, i.e., an N-(meth)acryloyl-based polymer chain. The content of the repeating unit derived from an N-(meth)acryloyl type monomer in the N-(meth)acryloyl-based polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of the polymer chain B may be a repeating unit derived from an N-(meth)acryloyl type monomer.

[0059] Examples of N-(meth)acryloyl type monomers include chain amides having N-(meth)acryloyl groups and cyclic amides having N-(meth)acryloyl groups. Examples of chain amides having N-(meth)acryloyl groups include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0060] Another example of the polymer chain B is a polymer chain containing an oxyalkylene unit as a main repeating unit, i.e., an oxyalkylene-based polymer chain. The content of the oxyalkylene unit in the oxyalkylene-based polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of the repeating units contained in the polymer chain B may be oxyalkylene units.

[0061] Examples of the oxyalkylene unit include an oxyethylene unit, an oxypropylene unit, and an oxybutylene unit. Each of these oxyalkylene units may be a repeating unit derived from a corresponding alkylene oxide. The oxyalkylene unit contained in the oxyalkylene polymer chain may be only one type, or may be two or more types. For example, the oxyalkylene polymer chain may contain a combination of an oxyethylene unit and an oxypropylene unit. In the oxyalkylene polymer chain containing two or more types of oxyalkylene units, the oxyalkylene units may be a random copolymer of the corresponding alkylene oxide, or may be a block copolymer or a graft copolymer.

[0062] Further examples of polymer chain B include polymer chains containing a repeating unit derived from an alkyl vinyl ether (e.g., a vinyl ether having an alkyl group having 1 to 10 carbon atoms), a polymer chain containing a repeating unit derived from a monocarboxylic acid vinyl ester (e.g., a vinyl ester of a monocarboxylic acid having 3 or more carbon atoms), a polymer chain in which a part of the VA units is acetalized with an aldehyde (e.g., an alkyl aldehyde having an alkyl group having 1 to 7 carbon atoms), and a polymer chain into which a cationic group (e.g., a cationic group having a quaternary ammonium structure) has been introduced.

[0063] As the polyvinyl alcohol-based polymer in the polishing composition according to the present invention, non-modified PVA may be used, modified PVA may be used, or non-modified PVA and modified PVA may be used in combination.In the embodiment of using non-modified PVA and modified PVA in combination, the amount of modified PVA used relative to the total amount of polyvinyl alcohol-based polymer contained in the polishing composition may be, for example, less than 95 mass%, 90 mass% or less, 75 mass% or less, 50 mass% or less, 30 mass% or less, 10 mass% or less, 5 mass% or less, or 1 mass% or less.The polishing composition according to the present invention may be preferably implemented, for example, in an embodiment in which only one or more non-modified PVA is used as the polyvinyl alcohol-based polymer.

[0064] Among these polyvinyl alcohol-based polymers, non-modified PVA, acetalized modified PVA, polyvinyl alcohol-polyvinylpyrrolidone copolymer, modified PVA containing oxyethylene units, and modified PVA containing repeating units derived from alkyl vinyl ether are more preferred.

[0065] According to some embodiments of the present invention, the weight average molecular weight of the polyvinyl alcohol-based polymer is 3×10 3 It is preferable that the value is 4×10 or more. 3 More preferably, it is 5×10 or more. 3 According to some embodiments of the present invention, the weight average molecular weight of the polyvinyl alcohol-based polymer is 100×10 or more. 4 It can be 50 x 10 4 The following is also good: 30×10 4 Less than 20×10 is fine. 4 Less than 10 x 10 is fine. 4 Preferably less than 9 x 10 4 More preferably, it is 8×10 4 It is more preferable that the weight average molecular weight is less than 100%. According to this embodiment, the dispersion stability is improved. As the weight average molecular weight of the polyvinyl alcohol-based polymer, a molecular weight calculated from a value based on gel permeation chromatography (GPC) (water-based, polyethylene oxide equivalent) can be adopted. As the measurement conditions of GPC, the measurement conditions described in the examples below can be adopted.

[0066] When the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid that is diluted with a dispersion medium or the like and used for polishing, the concentration (content) of the polyvinyl alcohol-based polymer in the polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, and particularly preferably 0.01% by mass or more, based on the total mass of the polishing composition, from the viewpoint of improving storage stability.In addition, in this case, the concentration (content) of the polyvinyl alcohol-based polymer in the polishing composition is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on the total mass of the polishing composition, from the viewpoint of storage stability, filterability, etc. That is, when the polishing composition is in the form of a concentrated liquid, the concentration (content) of the polyvinyl alcohol-based polymer is preferably 0.0001 mass% or more and 5 mass% or less, more preferably 0.0005 mass% or more and 3 mass% or less, even more preferably 0.001 mass% or more and 1 mass% or less, and particularly preferably 0.01 mass% or more and 1 mass% or less, relative to the total mass of the polishing composition.

[0067] When the polishing composition according to some embodiments of the present invention is in the state of a diluted solution, the concentration (content) of polyvinyl alcohol-based polymer in the polishing composition is preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, and particularly preferably 0.001% by mass or more, based on the total mass of the polishing composition, from the viewpoint of more excellent effect of improving surface quality.In addition, in this case, the concentration (content) of polyvinyl alcohol-based polymer is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less, based on the total mass of the polishing composition, from the viewpoint of more excellent effect of improving surface quality. That is, when the polishing composition is in a diluted state, the concentration (content) of the polyvinyl alcohol-based polymer is preferably 0.00005 mass% or more and 0.1 mass% or less, more preferably 0.0001 mass% or more and 0.05 mass% or less, even more preferably 0.0005 mass% or more and 0.01 mass% or less, and particularly preferably 0.001 mass% or more and 0.01 mass% or less, relative to the total mass of the polishing composition.

[0068] When two or more kinds of polyvinyl alcohol-based polymers are used, the above concentration (content) refers to the total amount thereof.

[0069] [Polyhydric alcohol with molecular weight of 600 or less] The polyhydric alcohol according to the present invention is a compound containing two or more hydroxyl groups in one molecule. In some embodiments of the present invention, the molecular weight of the polyhydric alcohol is 600 or less. When the molecular weight exceeds 600, although adsorption to the residue occurs, the polyhydric alcohol is likely to remain on the surface of the object to be polished after polishing, and the removal of the residue becomes insufficient. In addition, when a monohydric alcohol is used, adsorption to the residue on the surface of the object to be polished does not occur easily, and the residue cannot be sufficiently removed. In this specification, the polyhydric alcohol does not include the above-mentioned polyvinyl alcohol-based polymer. In addition, in this specification, the polyhydric alcohol does not include the block copolymer of ethylene oxide (EO) and propylene oxide (PO) described later.

[0070] The lower limit of the molecular weight of the polyhydric alcohol is not particularly limited, but is usually not less than 60. The molecular weight of the polyhydric alcohol can be calculated from the molecular formula. In addition, when the nominal value of the molecular weight is disclosed by the manufacturer or the like, the nominal value can be used. According to some embodiments of the present invention, the molecular weight of the polyhydric alcohol is preferably 65 or more, more preferably 70 or more, and particularly preferably 75 or more. In addition, the molecular weight of the polyhydric alcohol is preferably 500 or less, more preferably 450 or less, and particularly preferably 400 or less. That is, the molecular weight of the polyhydric alcohol is preferably 65 or more and 500 or less, more preferably 70 or more and 450 or less, and particularly preferably 75 or more and 400 or less.

[0071] Specific examples of polyhydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,4-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,6- Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 2,2-dimethylolheptane, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol , tripentaerythritol, trimethylolethane, trimethylolpropane, di(trimethylolpropane), and other saturated aliphatic polyhydric alcohols; cyclopentanediol, cyclopentane dimethanol, cyclopentane diethanol, cyclopentane dipropanol, cyclopentane dibutanol, cyclohexanediol, cyclohexane dimethanol, cyclohexane diethanol, cyclohexane dipropanol, cyclohexane dibutanol, cyclohexene diol, cyclohexene dimethanol, cyclohexene diethanol, cyclohexene dipropanol, cyclohexene dibutanol, cyclohexadiene diol, cyclohexadiene dimethanol, cyclohexadiene diethanol, cyclohexadiene dipropanol, cyclohexadiene dibutanol, hydrogenated bisphenol A, tricyclodecanediol, adamantyl diol, spiroglycol, and other alicyclic polyhydric alcohols;Polyhydric alcohols containing carbon-carbon double bonds, such as 2-butene-1,4-diol, 3-butene-1,4-diol, 2-pentene-1,5-diol, 3-hexene-1,6-diol, and 9-octadecene-7,12-diol; and carbon-carbon diols, such as acetylene diol, propargyl alcohol, 2,5-dimethyl-3-hexyne-2,5-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyne-3-ol, 3-methyl-1-butyne-3-ol, 3-methyl-1-pentyne-3-ol, 3-hexyne-2,5-diol, and 2-butyne-1,4-diol. Examples of the polyhydric alcohol include unsaturated aliphatic polyhydric alcohols such as triple bond-containing polyhydric alcohols (excluding compounds to which alkylene oxides are added); aromatic ring-containing polyhydric alcohols such as 1,3-benzenedimethanol and 1,4-benzenedimethanol; sugar alcohols such as glycerin, threitol, erythritol, arabinitol, xylitol, sorbitol, iditol, galactitol, mannitol, volemitol, perseitol, D-erythro-D-galacto-octitol, quercitol, and inositol; polyhydric alcohol polymers such as diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polyglycerin; and the like. These polyhydric alcohols may be used alone or in combination of two or more. The polyhydric alcohol may be a commercially available product or a synthetic product. For example, examples of commercially available carbon-carbon triple bond-containing polyhydric alcohols include Olfin D-10 and Surfynol 104 manufactured by Nissin Chemical Industry Co., Ltd.;

[0072] Among these polyhydric alcohols, glycerin, polyglycerin, 1,2-propanediol, and unsaturated aliphatic polyhydric alcohols are preferred. Among polyhydric alcohols, unsaturated aliphatic polyhydric alcohols are more preferred, polyhydric alcohol compounds containing carbon-carbon triple bonds (excluding compounds with alkylene oxide added) are even more preferred, and 2-butyne-1,4-diol is particularly preferred.

[0073] When the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid that is diluted with a dispersion medium or the like and used for polishing, the concentration (content) of the polyhydric alcohol in the polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, and particularly preferably 0.01% by mass or more, based on the total mass of the polishing composition, from the viewpoint of more excellent effect of improving surface quality. In addition, in this case, the concentration (content) of the polyhydric alcohol is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on the total mass of the polishing composition, from the viewpoint of more excellent effect of improving surface quality. That is, when the polishing composition is in the form of a concentrated liquid, the concentration (content) of the polyhydric alcohol in the polishing composition is preferably 0.0001 mass% or more and 5 mass% or less, more preferably 0.0005 mass% or more and 3 mass% or less, even more preferably 0.001 mass% or more and 1 mass% or less, and particularly preferably 0.01 mass% or more and 1 mass% or less, relative to the total mass of the polishing composition.

[0074] In some embodiments of the present invention, when the polishing composition is in the form of a diluted solution, the concentration (content) of the polyhydric alcohol in the polishing composition is preferably 0.00001% by mass or more, more preferably 0.00005% by mass or more, and even more preferably 0.0001% by mass or more, based on the total mass of the polishing composition, from the viewpoint of a more excellent effect of improving surface quality. In addition, in this case, the concentration (content) of the polyhydric alcohol is preferably 0.1% by mass or less, more preferably 0.08% by mass or less, and even more preferably 0.06% by mass or less, based on the total mass of the polishing composition, from the viewpoint of a more excellent effect of improving surface quality. That is, when the polishing composition is in the form of a diluted solution, the concentration (content) of the polyhydric alcohol in the polishing composition is preferably 0.00001% by mass or more and 0.1% by mass or less, more preferably 0.00005% by mass or more and 0.08% by mass or less, and even more preferably 0.0001% by mass or more and 0.06% by mass or less.

[0075] When two or more kinds of polyhydric alcohols are used, the above concentration (content) refers to the total amount thereof.

[0076] In addition, the polishing composition of the present invention may further contain a monohydric alcohol or a polyhydric alcohol having a molecular weight of more than 600, so long as it contains the above-mentioned polyhydric alcohol having a molecular weight of 600 or less.

[0077] [Water-soluble polymer] The polishing composition according to some embodiments of the present invention may further contain a water-soluble polymer (hereinafter, also simply referred to as "water-soluble polymer") different from the above-mentioned polyvinyl alcohol-based polymer. The water-soluble polymer adheres to the surface of the object to be polished and protects the surface of the object to be polished from uneven or excessive etching that may occur due to the action of the basic compound. This can further improve the quality of the surface of the object to be polished after polishing.

[0078] The water-soluble polymer may be any water-soluble polymer other than polyvinyl alcohol-based polymers (water-soluble polymers having VA units), and may have at least one functional group selected from the group consisting of cationic groups, anionic groups, and nonionic groups in the molecule. For example, water-soluble polymers having an anionic group, water-soluble polymers having a cationic group, water-soluble polymers having a nonionic group, etc. are mentioned. In this specification, the anionic group means a functional group that becomes an anion when a counter ion is dissociated. Also, the cationic group means a functional group that becomes a cation when a counter ion is dissociated or when it is bonded to a cationic species generated by ionization of another ionic compound. And, the nonionic group means a functional group that does not ionize.

[0079] The cationic group is not particularly limited, and examples thereof include an amino group or a salt thereof. Examples of water-soluble polymers having a cationic group include cationic cellulose, cationic guar gum, polydimethyldimethylenepyrrolidinium chloride, dimethyldimethylenepyrrolidinium chloride-(meth)acrylamide copolymer, (meth)acrylamide-(meth)acrylic acid-dimethyldiallylammonium chloride copolymer, N,N-dimethylaminoethyl diethyl(meth)acrylate sulfate, N,N-dimethyl polyethylene glycol(meth)acrylate, polyallylamine, glycidol-modified polyallylamine, and methyldiallylamine-sulfur dioxide copolymer.

[0080] Examples of the anionic group include a carboxy group, a sulfo group, a phosphate group, or a salt thereof.

[0081] Examples of water-soluble polymers having a carboxy group or a salt group thereof (carboxy group-containing water-soluble polymers) include poly(meth)acrylic acid and derivatives thereof, and salts thereof.

[0082] Examples of polymers having a sulfo group or a salt group (sulfo group-containing water-soluble polymers) include sulfonic acid-modified polyvinyl alcohol (sulfonic acid group-containing polyvinyl alcohol, sulfonic acid group-containing modified polyvinyl alcohol), sulfonic acid group-containing polystyrenes such as polystyrene sulfonic acid (sulfonic acid group-containing modified polystyrenes), sulfonic acid-modified polyvinyl acetates (sulfonic acid group-containing polyvinyl acetate, sulfonic acid group-containing modified polyvinyl acetate), sulfonic acid group-containing polyesters (sulfonic acid group-containing modified polyesters), copolymers of (meth)acrylic acid-sulfonic acid group-containing monomers-sulfonic acid group-containing monomers such as copolymers of (meth)acrylic acid-sulfonic acid group-containing monomers, derivatives thereof, and salts thereof.

[0083] Phosphonic acid group (-P(=O)(OH) 2 Examples of the polymer having a group of 2-hydroxyethyl (meth)acryloyl phosphate or a salt thereof (a water-soluble polymer containing a phosphonic acid group) include (co)polymers containing structural units composed of monomers such as 2-hydroxyethyl (meth)acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, and derivatives thereof, as well as salts thereof. In addition, examples of the polymer having a group of 2-hydroxyethyl (meth)acryloyl phosphate or a salt thereof ... derivatives thereof, as well as salts thereof. In addition, examples of the polymer having a group of 2-hydroxyethyl (meth)acryloyl phosphate or a salt thereof include (co)polymers containing structural units composed of monomers such as 2-hydroxyethyl (meth)acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, derivatives thereof, as well as salts thereof. Examples of such monomers include (co)polymers containing structural units composed of monomers such as uryl phosphate, (meth)acryloyloxystearyl phosphate, (meth)acryloyloxy-1,4-dimethylcyclohexyl phosphate, etc., and derivatives thereof, as well as salts thereof. Here, the term "(co)polymer" refers to a copolymer or homopolymer. Examples of monomers constituting the other structural units of the copolymer include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene; hydroxy group-containing vinyl monomers such as hydroxystyrene, N-methylol(meth)acrylamide, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, polyethylene glycol mono(meth)acrylate, and 2-hydroxyethylpropenyl ether; and alkyl(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, dodecyl(meth)acrylate, hexadecyl(meth)acrylate, and eicosyl(meth)acrylate. In this specification, "having a phosphonic acid group or a salt thereof" means that the compound has a phosphonic acid group (-P(=O)(OH) 2 ) or a salt thereof, for example, a phosphonic acid group or a salt thereof may have a partial structure represented by a phosphate group (-OP(=O)(OH) 2 ) or a salt thereof.

[0084] Examples of the water-soluble polymer having a nonionic group include compounds containing, in the molecule, a hydroxy group, an acyloxy group, a sulfo group, a vinyl structure, a polyoxyalkylene structure, a heterocyclic structure, an amide structure, an imide structure, etc. Examples of the water-soluble polymer having a nonionic group include cellulose derivatives, starch derivatives, and nitrogen atom-containing polymers.

[0085] The cellulose derivative refers to a cellulose in which some of the hydroxyl groups of the cellulose are replaced with other different substituents. Examples of the cellulose derivative include hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose.

[0086] Starch derivatives refer to starch or starch in which some of the hydroxyl groups have been replaced with other different substituents, such as pullulan.

[0087] Examples of the nitrogen atom-containing polymer include polymers containing N-vinyl type monomer units; polymers containing N-(meth)acryloyl type monomer units; and the like. Examples of N-vinyl type polymers include polymers containing repeating units derived from monomers having nitrogen-containing heterocycles (e.g., lactam rings). Examples of such polymers include homopolymers and copolymers of N-vinyl lactam type monomers (e.g., copolymers having a copolymerization ratio of N-vinyl lactam type monomers exceeding 50% by mass), homopolymers and copolymers of N-vinyl chain amides (e.g., copolymers having a copolymerization ratio of N-vinyl chain amides exceeding 50% by mass), and the like. Specific examples of N-vinyl lactam type monomers (i.e., compounds having a lactam structure and an N-vinyl group in one molecule) include N-vinyl pyrrolidone (VP), N-vinyl piperidone, N-vinyl morpholinone, N-vinyl caprolactam (VC), N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, and the like. Specific examples of polymers containing N-vinyl lactam type monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), block copolymers containing polymer chains containing one or both of VP and VC, alternating copolymers, graft copolymers, etc. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionamide, N-vinylbutyric acid amide, etc.

[0088] Examples of N-(meth)acryloyl type polymers include homopolymers and copolymers of N-(meth)acryloyl type monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl type monomers exceeds 50 mass %). Examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, and Nn-butyl (meth)acrylamide; and N,N-dialkyl (meth)acrylamides such as N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, and N,N-di(n-butyl) (meth)acrylamide. Examples of polymers containing chain amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by mass).

[0089] Examples of cyclic amides having an N-(meth)acryloyl group include N-acryloylmorpholine, N-acryloylthiomorpholine, N-acryloylpiperidine, N-acryloylpyrrolidine, N-methacryloylmorpholine, N-methacryloylpiperidine, and N-methacryloylpyrrolidine. Examples of polymers containing cyclic amides having an N-(meth)acryloyl group as monomer units include acryloylmorpholine-based polymers. Typical examples of acryloylmorpholine-based polymers include homopolymers of N-acryloylmorpholine (ACMO) (poly N-acryloylmorpholine (PACMO)) and copolymers of ACMO (for example, copolymers with a copolymerization ratio of ACMO exceeding 50% by mass). In the acryloylmorpholine-based polymer, the ratio of the number of moles of ACMO units to the number of moles of all repeating units is usually 50% or more, and suitably 80% or more (e.g., 90% or more, typically 95% or more). All repeating units of the water-soluble polymer may be substantially composed of ACMO units.

[0090] When the water-soluble polymer is in the form of a salt, examples of the salt include, but are not limited to, alkali metal salts such as sodium salts and potassium salts, salts of Group 2 elements such as calcium salts and magnesium salts, amine salts, and ammonium salts.

[0091] The weight average molecular weight (Mw) of the water-soluble polymer is, for example, about 200×10 4 It may be less than or equal to about 150×10 4 From the viewpoint of cleaning properties, etc., it is preferable to use a value of about 100×10 4 Less than or equal to 50×10 4 From the viewpoint of protecting the polishing surface, the Mw of the water-soluble polymer may be, for example, 0.5×10 4 In some embodiments, the Mw is 1.0×10 or more. 4 The above is appropriate, and 1.5 x 10 4 It may be more than 2 x 10 4 or more, for example 5×10 4 More than 10 x 10 is fine.4 More than that is fine.

[0092] The Mw of the water-soluble polymer can be the weight average molecular weight calculated from a value based on gel permeation chromatography (GPC) (water-based, polyethylene oxide equivalent). The measurement conditions for GPC can be the measurement conditions described in the Examples below.

[0093] The water-soluble polymer may be used alone or in combination of two or more kinds. In addition, the water-soluble polymer may be a commercially available product or a synthetic product.

[0094] As the water-soluble polymer, from the viewpoint of better exerting the intended effects of the present invention, a homopolymer of N-acryloylmorpholine (ACMO) (poly N-acryloylmorpholine (PACMO)) is more preferable.

[0095] When the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid that is diluted with a dispersion medium or the like and used for polishing, the content (concentration) of the water-soluble polymer in the concentrated liquid is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more. In addition, in this case, the content (concentration) of the water-soluble polymer in the concentrated liquid of the polishing composition is not particularly limited, but is preferably 15% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of storage stability, etc. That is, when the polishing composition is in the form of a concentrated liquid, the content (concentration) of the water-soluble polymer is preferably 0.001% by mass or more and 15% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less, and even more preferably 0.01% by mass or more and 3% by mass or less.

[0096] When the polishing composition according to some embodiments of the present invention is in the state of a diluted solution, the concentration (content) of the water-soluble polymer in the polishing composition is preferably 0.0001 mass% or more, more preferably 0.0003 mass% or more, more preferably 0.0005 mass% or more, particularly preferably 0.001 mass% or more, and most preferably 0.003 mass% or more, based on the total mass of the polishing composition.In addition, in this case, the upper limit of the concentration (content) of the water-soluble polymer in the polishing composition is preferably 5 mass% or less, more preferably 1 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.2 mass% or less, even more preferably 0.1 mass% or less, and particularly preferably 0.05 mass% or less, based on the total mass of the polishing composition. That is, when the polishing composition is in the state of a diluted solution, the concentration (content) of the water-soluble polymer is preferably 0.0001% by mass or more and 5% by mass or less, more preferably 0.0003% by mass or more and 1% by mass or less, even more preferably 0.0005% by mass or more and 0.5% by mass or less, even more preferably 0.001% by mass or more and 0.2% by mass or less, and particularly preferably 0.003% by mass or more and 0.1% by mass or less.When the polishing composition is in the state of a diluted solution, the concentration (content) of the water-soluble polymer in the polishing composition may be 0.001% by mass or more and 0.05% by mass or less, or may be 0.003% by mass or more and 0.05% by mass or less.

[0097] When two or more kinds of water-soluble polymers are used, the above concentration (content) refers to the total amount thereof.

[0098] [Dispersion medium] In some embodiments of the present invention, the polishing composition preferably contains a dispersion medium for dispersing each component. The dispersion medium (particularly water) has the function of dissolving or dispersing the components contained in the polishing composition.

[0099] The dispersion medium may be a mixed solvent of water and an organic solvent for dispersing or dissolving each component. In this case, examples of the organic solvent used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, which are organic solvents miscible with water. In addition, these organic solvents may be used without mixing with water, and then each component may be dispersed or dissolved, and then mixed with water. These organic solvents may be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the dispersion medium contains water. According to a more preferred embodiment of the present invention, the dispersion medium is substantially composed of water. Note that the above term "substantially" means that a dispersion medium other than water may be included as long as the effects of the present invention can be achieved. More specifically, the dispersion medium is preferably composed of 90% by mass or more and 100% by mass or less of water and 0% by mass or more and 10% by mass or less of a dispersion medium other than water, and more preferably composed of 99% by mass or more and 100% by mass or less of water and 0% by mass or more and 1% by mass or less of a dispersion medium other than water. According to the most preferred embodiment of the present invention, the dispersion medium is only water.

[0100] It is preferable that the water contains as few impurities as possible in order to prevent contamination of the object to be polished and inhibition of the action of other components. For example, water having a total transition metal ion content of 100 ppb or less is preferable. Here, the purity of the water can be increased by, for example, removing impurity ions using ion exchange resin, removing foreign matter using a filter, distillation, or other operations. Specifically, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, or the like as the water.

[0101] [Surfactants] The polishing composition according to the present invention may contain a surfactant as necessary. By adding a surfactant to the polishing composition, the haze on the surface of the object to be polished after polishing can be reduced better. Any of anionic, cationic, nonionic, and amphoteric surfactants can be used as the surfactant. Usually, anionic or nonionic surfactants can be preferably used. From the viewpoint of low foaming and ease of pH adjustment, nonionic surfactants are more preferable. For example, nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyalkylene adducts); and copolymers of multiple types of oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers). The above surfactant preferably contains a surfactant containing a polyoxyalkylene structure. The surfactants may be used alone or in combination of two or more.

[0102] Specific examples of nonionic surfactants containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, Examples of the polyoxyethylene oleyl ether include polyoxyethylene phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene lauryl amine, polyoxyethylene stearyl amine, polyoxyethylene oleyl amine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitoate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.Among these, preferred surfactants include block copolymers of EO and PO (particularly, PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (for example, polyoxyethylene decyl ether).

[0103] The weight average molecular weight (Mws) of the surfactant is typically less than 5,000, and is preferably 4,000 or less (e.g., 3,000 or less) from the viewpoint of filterability, washability, etc. In addition, the Mws of the surfactant is usually appropriate to be 200 or more from the viewpoint of surface activity, etc., and is preferably 250 or more (e.g., 300 or more) from the viewpoint of haze reduction effect, etc. The more preferable range of the Mws of the surfactant may vary depending on the type of the surfactant. For example, when a polyoxyethylene alkyl ether is used as the surfactant, its Mws is preferably 1,500 or less, and may be 1,000 or less (e.g., 500 or less). As the Mws of the surfactant, a molecular weight calculated from a value based on gel permeation chromatography (GPC) (water-based, polyethylene oxide equivalent) or a molecular weight calculated from a chemical formula can be adopted. The measurement conditions of GPC can be the same as those of the water-soluble polymer described above.

[0104] When the polishing composition according to the present invention contains a surfactant, the content is not particularly limited as long as it is within a range that does not significantly impair the effects of the present invention. Usually, from the viewpoint of cleaning property, the content of the surfactant relative to 100 parts by mass of abrasive grains is appropriate to be 20 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less (for example, 8 parts by mass or less). From the viewpoint of better exerting the effect of using the surfactant, the content of the surfactant relative to 100 parts by mass of abrasive grains is appropriate to be 0.001 parts by mass or more, preferably 0.005 parts by mass or more, and may be 0.01 parts by mass or more, or may be 0.05 parts by mass or more. When two or more kinds of surfactants are used, the above content refers to the total amount.

[0105] [Other ingredients] The polishing composition of the present invention may further contain known additives that can be used in polishing compositions, such as chelating agent (complexing agent), pH adjuster, and antifungal agent (preservative), within the range that does not inhibit the effect of the present invention. Hereinafter, the chelating agent, pH adjuster, and antifungal agent (preservative) will be explained. In addition, the oxidizing agent will be explained.

[0106] (chelating agent) The chelating agent captures metal impurity components in the polishing system to form a complex, thereby suppressing metal contamination on the surface of the object to be polished. The polishing composition according to one embodiment of the present invention may further contain a chelating agent.

[0107] Specific examples of the chelating agent include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents.Specific examples of the aminocarboxylic acid chelating agent include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate.Specific examples of the organic phosphonic acid chelating agent 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, α-methylphosphonosuccinic acid, etc. Among these chelating agents, it is preferable to use an organic phosphonic acid chelating agent, particularly ethylenediaminetetrakis(methylenephosphonic acid). The chelating agent may be used alone or in combination of two or more.

[0108] (pH adjuster) In the polishing composition of the present invention, the pH can be adjusted by each component described above, but a pH adjuster may also be used to adjust to a desired pH.Therefore, the polishing composition of the present invention may further contain a pH adjuster.The pH adjuster may include compounds other than the basic compounds described above, such as inorganic acids and organic acids.These may be used alone or in combination of two or more.

[0109] Specific examples of inorganic acids that can be used as pH adjusters include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Among these, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid are preferred, and nitric acid is more preferred.

[0110] Specific examples of organic acids that can be used as pH adjusters include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, 10-camphorsulfonic acid, and isethionic acid.

[0111] As the pH adjuster, a salt such as an alkali metal salt of an inorganic or organic acid may be used instead of or in combination with an inorganic or organic acid. In the case of a combination of a weak acid and a strong base, a strong acid and a weak base, or a weak acid and a weak base, a pH buffering effect can be expected.

[0112] <pH of polishing composition> The pH of the polishing composition according to some embodiments of the present invention is preferably 7.0 or more, more preferably 7.5 or more, even more preferably 8.0 or more, particularly preferably 8.5 or more, and most preferably 9.0 or more. The pH of the polishing composition is preferably 12.5 or less, more preferably 12.0 or less, even more preferably 11.5 or less, particularly preferably 11.0 or less, and most preferably 10.5 or less. That is, the pH of the polishing composition is preferably 7.0 or more and 12.5 or less, more preferably 7.5 or more and 12.0 or less, even more preferably 8.0 or more and 11.5 or less, particularly preferably 8.5 or more and 11.0 or less, and most preferably 9.0 or more and 10.5 or less. In one embodiment, the pH of the polishing composition is 9.5 or more and 11.0 or less. If the pH of the polishing composition is in such a range, the polyhydric alcohol acts more effectively on the surface of the object to be polished, and the surface quality of the object to be polished can be further improved.

[0113] The concentration (content) of the pH adjuster can be appropriately adjusted within the range in which the effects of the present invention are achieved. The pH of the polishing composition can be measured, for example, by a pH meter (for example, a pH meter (model number: LAQUA) manufactured by Horiba, Ltd.).

[0114] (Anti-mold agent (preservative)) The type of antifungal agent (preservative) is not particularly limited and can be appropriately selected according to the desired use and purpose.Specific examples include isothiazoline preservatives such as 1,2-benzoisothiazol-3(2H)-one (BIT), 2-methyl-4-isothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3-one, and phenoxyethanol.

[0115] (Oxidizing agent) It is preferable that the polishing composition according to some embodiments of the present invention does not substantially contain an oxidizing agent. If an oxidizing agent is contained in the polishing composition, the surface of the object to be polished (especially a silicon wafer) is oxidized to form an oxide film, which increases the required polishing time. Specific examples of the oxidizing agent include hydrogen peroxide (H 2 O 2 ), sodium persulfate, ammonium persulfate, sodium dichloroisocyanurate, etc. In addition, the polishing composition "substantially does not contain an oxidizing agent" means that an oxidizing agent is not contained at least intentionally. Therefore, a polishing composition that inevitably contains a small amount of oxidizing agent (for example, the molar concentration of the oxidizing agent in the polishing composition is 0.001 mol / L or less, preferably 0.0005 mol / L or less, more preferably 0.0001 mol / L or less, further preferably 0.00005 mol / L or less, particularly preferably 0.00001 mol / L or less) due to raw materials, manufacturing method, etc., can be included in the concept of a polishing composition that does not substantially contain an oxidizing agent as described here.

[0116] [Method of manufacturing the polishing composition] The method for producing the polishing composition according to the present invention is not particularly limited. For example, the polishing composition can be produced by sequentially adding abrasive grains, a basic compound, a polyvinyl alcohol-based polymer, a polyhydric alcohol, and other components that are added as necessary, and stirring them in a dispersion medium.

[0117] (Form of polishing composition, etc.) The polishing composition according to the present invention may be a one-liquid type, or may be a multi-liquid type consisting of two or more liquids. The polishing composition described above may be used for polishing as it is, or may be prepared by adding water to dilute the concentrated solution of the polishing composition, or in the case of a multi-agent type polishing composition, diluting it with an aqueous solution containing water and a part of the constituents, and then used for polishing. For example, the concentrated solution of the polishing composition can be stored or transported, and then diluted at the time of use to prepare the polishing composition.

[0118] A polishing composition in a concentrated form is advantageous in terms of convenience and cost reduction during production, distribution, storage, etc. The concentration ratio can be, for example, about 2 times or more and 100 times or less in volume conversion, and usually about 5 times or more and 50 times or less is appropriate. The concentration ratio of the polishing composition according to a preferred embodiment is 10 times or more and 45 times or less, for example, 15 times or more and 40 times or less.

[0119] [Polished object] The polishing composition according to the present invention is used for polishing a surface made of a silicon material.

[0120] The silicon material preferably contains at least one material selected from the group consisting of silicon single crystal, amorphous silicon, and polysilicon. From the viewpoint of obtaining the effect of the present invention more significantly, the silicon material is more preferably silicon single crystal or polysilicon, and particularly preferably silicon single crystal. The polishing composition according to some embodiments of the present invention is particularly preferably used for polishing a substrate (e.g., silicon wafer) having a surface made of silicon single crystal.

[0121] The silicon wafer to be polished using the polishing composition of the present invention may be either p-type or n-type. In addition, the crystal orientation of the silicon wafer is not particularly limited. <100> , <110> , <111> Either of the above may be used.

[0122] [Polishing method] Another aspect of the present invention provides a polishing method comprising polishing a surface made of a silicon material using the polishing composition. The polishing composition according to some embodiments of the present invention is particularly suitable for use in a final polishing step, since it has an excellent effect of improving the surface quality of the object to be polished. That is, the polishing method according to some embodiments of the present invention is suitable for use in a final polishing step. Therefore, according to the present invention, a manufacturing method of an object to be polished (e.g., a manufacturing method of a silicon wafer) including a final polishing step using the polishing composition is also provided. The final polishing step refers to the last polishing step in the manufacturing process of the object (i.e., a step in which no further polishing is performed after the step). The polishing composition according to some embodiments of the present invention may also be used in a polishing step upstream of the final polishing step (a step between the rough polishing step and the final polishing step), for example, a polishing step performed immediately before the final polishing step.

[0123] As described above, the polishing composition according to some embodiments of the present invention is preferably used for polishing silicon wafers. The polishing composition according to some embodiments of the present invention is particularly suitable as a polishing composition used in the final polishing step of silicon wafers. More specifically, the polishing composition according to some embodiments of the present invention is suitable for use in polishing silicon wafers that have been prepared to have a surface roughness of 0.01 nm or more and 100 nm or less by a step upstream of the final polishing step.

[0124] As the polishing apparatus, a general polishing apparatus can be used which is equipped with a holder for holding a substrate having an object to be polished, a motor capable of changing the rotation speed, and the like, and has a polishing platen to which a polishing pad (polishing cloth) can be attached.

[0125] The polishing pad can be any type, including general nonwoven fabric, polyurethane, suede, etc. The polishing pad is preferably provided with grooves for collecting the polishing composition.

[0126] The polishing conditions are appropriately set depending on the stage of the polishing process in which the polishing composition is used.

[0127] In the preliminary polishing step, either a double-sided polishing machine or a single-sided polishing machine may be used, but a single-sided polishing machine is preferably used. The rotation speed of the platen is usually about 10 rpm or more and 100 rpm or less, preferably about 20 rpm or more and 60 rpm or less. In the final polishing step, a single-sided polishing machine is preferably used, and the rotation speed of the platen is usually about 10 rpm or more and 100 rpm or less, preferably about 20 rpm or more and 60 rpm or less, more preferably about 25 rpm or more and 55 rpm or less. At such a rotation speed, defects on the surface of the object to be polished can be significantly reduced.

[0128] The object to be polished is usually pressed by a platen. The pressure can be selected appropriately, but in the preliminary polishing process, it is usually preferably about 5 kPa or more and 30 kPa or less, more preferably about 10 kPa or more and 25 kPa or less. In the final polishing process, it is usually preferably about 5 kPa or more and 30 kPa or less, more preferably about 10 kPa or more and 20 kPa or less. With such a pressure, defects on the surface of the object to be polished can be significantly reduced.

[0129] The supply rate of the polishing composition can also be appropriately selected according to the size of the platen, but in consideration of economic efficiency, in the case of the preliminary polishing step, it is usually preferably about 0.1 L / min to 5 L / min, and more preferably about 0.2 L / min to 2 L / min. In the case of the finish polishing step, it is usually preferably about 0.1 L / min to 5 L / min, and more preferably about 0.2 L / min to 2 L / min. By using such a supply rate, the surface of the object to be polished can be polished efficiently, and the haze level of the surface of the object to be polished can be significantly reduced.

[0130] There are no particular limitations on the temperature at which the polishing composition is maintained in the polishing apparatus, but from the standpoint of the stability of the polishing rate and the reduction of the haze level, it is usually preferable for the temperature to be about 15°C or higher and 40°C or lower, and more preferably about 18°C ​​or higher and 25°C or lower.

[0131] The above polishing conditions (polishing device settings) are merely examples, and may be outside the above range, or the settings may be changed as appropriate. Such conditions can be set appropriately by a person skilled in the art.

[0132] Furthermore, it is preferable to perform cleaning and drying after polishing. The method and conditions for these operations are not particularly limited, and known methods and conditions may be appropriately adopted. For example, the SC-1 cleaning solution (ammonium hydroxide (NH 4 OH) and hydrogen peroxide (H 2 O 2 ) and water (H 2 O), SC-2 cleaning solution (hydrogen chloride (HCl) and H 2 O 2 and H 2 Examples of the cleaning solution that can be used include a cleaning solution of ozone water (a mixture of ozone and fluorine), a cleaning solution of ozone water, a cleaning solution of hydrofluoric acid, etc. The temperature of the cleaning solution can be in the range of, for example, from room temperature (typically about 15° C. to 25° C.) to about 90° C.

[0133] Although the embodiments of the present invention have been described in detail, it is apparent that the same are illustrative and exemplary, and not restrictive, and the scope of the present invention should be interpreted by the appended claims.

[0134] The present invention encompasses the following aspects and configurations: 1. A polishing composition used for polishing a surface made of a silicon material, comprising: an abrasive grain; a basic compound; a polyvinyl alcohol-based polymer; and a polyhydric alcohol having a molecular weight of 600 or less. 2. The polishing composition according to 1 above, wherein the polyhydric alcohol is an unsaturated aliphatic polyhydric alcohol. 3. The polishing composition according to 2 above, wherein the unsaturated aliphatic polyhydric alcohol is a carbon-carbon triple bond-containing polyhydric alcohol. 4. The polishing composition according to any one of 1. to 3. above, further comprising a water-soluble polymer different from the polyvinyl alcohol-based polymer: 5. The polishing composition according to any one of 1. to 4. above, further comprising a dispersion medium: 6. A concentrated solution of the polishing composition according to any one of 1. to 5. above: 7. A polishing method comprising polishing a surface of a silicon material with the polishing composition according to any one of 1. to 5. above. EXAMPLES

[0135] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were performed under the conditions of room temperature (25°C) / relative humidity of 40% RH or more and 50% RH or less.

[0136] <Average primary particle size of abrasive grains> The average primary particle size of the abrasive grains was calculated from the specific surface area of ​​the colloidal silica measured by the BET method using a surface area measuring device manufactured by Micromeritics, product name "Flow Sorb II 2300", and the density of the abrasive grains.

[0137] <pH of polishing composition> The pH was measured using a pH meter (a glass electrode type hydrogen ion concentration indicator (model number F-2372) manufactured by Horiba, Ltd.). More specifically, a three-point calibration was performed using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C), neutral phosphate pH buffer solution, pH: 6.86 (25°C), carbonate pH buffer solution, pH: 10.01 (25°C)). The glass electrode was then placed in the polishing composition to be measured for 2 minutes or more. After the pH of the polishing composition stabilized, the pH of the polishing composition was measured.

[0138] <Measurement of weight average molecular weight> The weight average molecular weight was measured by GPC under the following conditions: <GPC measurement conditions> Measuring device: HLC-8320GPC (Tosoh) Sample concentration: 0.1% by mass Column: TSKgel GMPWXL Detector: Differential refractometer Eluent: 100mM sodium nitrate aqueous solution Flow rate: 1mL / min Measurement temperature: 40℃ Molecular weight conversion: Polyethylene glycol conversion Sample injection volume: 200 μL.

[0139] Example 1 The abrasive grains are colloidal silica (average primary particle size: 25 nm), the basic compound is ammonia, and the weight-average molecular weight (Mw) of the water-soluble polymer is 3.5×10 5 Poly(N-acryloylmorpholine) (PACMO) with a weight average molecular weight (Mw) of 1.0×10 4 A concentrated solution of a polishing composition was prepared by mixing acetalized modified polyvinyl alcohol (Ac-PVA) as a surfactant (ethylene oxide addition mole number: 5, C10PEO5), glycerin as a polyhydric alcohol, and ion-exchanged water. The concentrated solution of the polishing composition obtained was diluted with ion-exchanged water to a volume ratio of 40 times to obtain a polishing composition containing 0.13 mass% abrasive grains, 0.008 mass% ammonia, 0.004 mass% PACMO, 0.003 mass% Ac-PVA, 0.0006 mass% C10PEO5, and 0.0001 mass% glycerin.

[0140] Example 2 A polishing composition was obtained in the same manner as in Example 1, except that 1,2-propanediol was used instead of glycerin.

[0141] Example 3 A polishing composition was obtained in the same manner as in Example 1, except that 2-butyne-1,4-diol was used instead of glycerin.

[0142] Example 4 A polishing composition was obtained in the same manner as in Example 1, except that polyglycerin (molecular weight: 300, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was used at a concentration of 0.05 mass% instead of glycerin. The molecular weight of the polyglycerin was the nominal value provided by the manufacturer.

[0143] Example 5 A polishing composition was obtained in the same manner as in Example 1, except that a random copolymer of vinyl alcohol and N-vinylpyrrolidone (PVA-PVP, weight average molecular weight: 6000) was used instead of Ac-PVA.

[0144] Example 6 A polishing composition was obtained in the same manner as in Example 1, except that polyvinyl alcohol (PVA, weight average molecular weight: 70,000) was used instead of Ac-PVA.

[0145] Comparative Example 1 A polishing composition was obtained in the same manner as in Example 1, except that glycerin was not used.

[0146] Comparative Example 2 A polishing composition was obtained in the same manner as in Example 1, except that ethanol was used instead of glycerin.

[0147] Comparative Example 3 Except for using polyethylene glycol (molecular weight: 1000, manufactured by Tokyo Chemical Industry Co., Ltd.) instead of glycerin, a polishing composition was obtained in the same manner as in Example 1. The molecular weight of the polyethylene glycol is the nominal value provided by the manufacturer.

[0148] Comparative Example 4 A polishing composition was obtained in the same manner as in Example 5, except that 2-butyne-1,4-diol was not used.

[0149] Comparative Example 5 A polishing composition was obtained in the same manner as in Example 6, except that 2-butyne-1,4-diol was not used.

[0150] The compositions of the polishing compositions of Examples and Comparative Examples are shown in the following Table 1. In addition, in the following Table 1, "-" indicates that the component is not contained.

[0151] [Table 1]

[0152] [Silicon wafer polishing] The surface of the silicon wafer was preliminarily polished under the following polishing condition 1. Next, the preliminarily polished surface of the silicon wafer was pre-polished using the polishing compositions of the Examples and Comparative Examples under the following polishing condition 2. Furthermore, the preliminarily polished surface of the silicon wafer was final polished (finish polished) using the polishing compositions of the Examples and Comparative Examples under the following polishing condition 3.

[0153] The polished silicon wafer was then removed from the polishing machine. The removed silicon wafer was cleaned using a single-wafer wafer cleaning machine. First, the silicon wafer was cleaned with an ozone water cleaning solution for 60 seconds, and then cleaned with an SC-1 cleaning solution and a brush for 110 seconds. Next, the silicon wafer was cleaned with an ozone water cleaning solution for 20 seconds, and then cleaned with a hydrofluoric acid cleaning solution for 15 seconds. This ozone water cleaning and hydrofluoric acid cleaning constitute one set, and a total of three sets of cleaning were performed on the silicon wafer. After cleaning, the silicon wafer was cleaned with an ozone water cleaning solution for an additional 20 seconds. The silicon wafer was then dried.

[0154] [Polished object] Wafer: p-type COP (Crystal Orginate 65d Particle) free, crystal orientation <100> A silicon wafer having a size of 300 mm was prepared.

[0155] [Preliminary polishing: Polishing condition 1] Grinding machine: PNX-332B (manufactured by Okamoto Machine Tools Co., Ltd.) Polishing pad: SUBA400 (manufactured by Nitta DuPont Co., Ltd.) Polishing load: 20kPa Platen rotation speed: 20 rpm Carrier rotation speed: 20 rpm Polishing time: 2 min -Temperature of cooling water for surface plate: 20℃ Temperature of polishing compound: 20℃ Polishing compound supply rate: 1L / min Polishing composition for preliminary polishing: a polishing composition containing 0.6 mass % of abrasive grains (colloidal silica having an average primary particle size of 35 nm) and 0.08 mass % of tetramethylammonium hydroxide (TMAH) in deionized water.

[0156] [Pre-polishing: Polishing conditions 2] Grinding machine: PNX-332B (manufactured by Okamoto Machine Tools Co., Ltd.) Polishing pad: POLYPAS275NX (manufactured by Fujibo Ehime Co., Ltd.) Polishing load: 16kPa Platen rotation speed: 52 rpm Carrier rotation speed: 50 rpm Polishing time: 2 min -Temperature of cooling water for surface plate: 20℃ Temperature of polishing compound: 20℃ Polishing compound supply rate: 1.5L / min Polishing composition for pre-polishing: Polishing compositions of the examples and comparative examples listed in Table 1.

[0157] [Finishing polishing: Polishing condition 3] Grinding machine: PNX-332B (manufactured by Okamoto Machine Tools Co., Ltd.) Polishing pad: POLYPAS27NX (manufactured by Fujibo Co., Ltd.) Polishing load: 20kPa Platen rotation speed: 52 rpm Carrier rotation speed: 50 rpm Polishing time: 2 min -Temperature of cooling water for surface plate: 20℃ Temperature of polishing compound: 20℃ Polishing compound supply rate: 1.5L / min Polishing composition for final polishing: Polishing compositions of Examples and Comparative Examples listed in Table 1.

[0158] [evaluation] The number of defects (LLS, Localized Light Scatterers) on the wafer surface was measured using the dried silicon wafer. For the measurement, a wafer inspection device (manufactured by KLA-Tencor Corporation, product name "SURFSCAN SP5") was used, and the measurement mode was set to Oblique mode. The evaluation results are shown in Table 2 below. Note that Table 2 below shows the relative values ​​(LLS ratios) of the number of defects in Examples 1 to 4 when the number of defects (LLS) in Comparative Example 1 is set to 100, the relative values ​​(LLS ratios) of the number of defects in Example 5 when the number of defects (LLS) in Comparative Example 4 is set to 100, and the relative values ​​(LLS ratios) of the number of defects in Example 6 when the number of defects (LLS) in Comparative Example 5 is set to 100.

[0159] [Table 2]

[0160] As is clear from Table 2 above, it was found that when the polishing compositions of Examples 1 to 4 were used, the surface quality of the object to be polished after polishing could be improved compared to the polishing compositions of Comparative Examples 1 to 3. It was found that when the polishing composition of Example 5 was used, the surface quality of the object to be polished after polishing could be improved compared to the polishing composition of Comparative Example 4. It was found that when the polishing composition of Example 6 was used, the surface quality of the object to be polished after polishing could be improved compared to the polishing composition of Comparative Example 5.

Claims

1. A polishing composition used for polishing a surface made of a silicon material, comprising: A polishing composition comprising an abrasive, a basic compound, a polyvinyl alcohol-based polymer, and a polyhydric alcohol having a molecular weight of 600 or less.

2. The polishing composition according to claim 1 , wherein the polyhydric alcohol is an unsaturated aliphatic polyhydric alcohol.

3. 3. The polishing composition according to claim 2, wherein the unsaturated aliphatic polyhydric alcohol is a carbon-carbon triple bond-containing polyhydric alcohol.

4. The polishing composition according to claim 1 or 2, further comprising a water-soluble polymer different from the polyvinyl alcohol-based polymer.

5. The polishing composition according to claim 1 or 2, further comprising a dispersion medium.

6. A concentrated solution of the polishing composition according to claim 1 or 2.

7. A polishing method comprising polishing a surface of a silicon material with the polishing composition according to claim 1 or 2.

Images