Grinding composition

Abstract

To provide a polishing composition that can realize a high-quality surface.SOLUTION: A polishing composition according to the present invention includes silica particles (A), a basic compound (B), a first water-soluble polymer (C1), a second water-soluble polymer (C2), and water (D), and the first water-soluble polymer (C1) is a polyvinyl alcohol polymer. The ratio (ER2 / ER1) of the etching rate ER1 based on a predetermined etching rate measurement of the first water-soluble polymer (C1) to the etching rate ER2 based on a predetermined etching rate measurement of the second water-soluble polymer (C2) satisfies the following relationship: 0.6≤ER2 / ER1≤10.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polishing composition. [Background technology]

[0002] Precision polishing using a polishing composition is performed on the surfaces of materials such as metals, semi-metals, non-metals, and their oxides. For example, the surface of a silicon wafer, which is used as a component of a semiconductor device, is generally finished to a high-quality mirror surface through a lapping step (rough polishing step) and a polishing step (precise polishing step). The polishing step typically includes a pre-polishing step (preliminary polishing step) and a finish polishing step (final polishing step). Patent documents 1 to 3 are cited as technical documents related to polishing compositions primarily used for polishing semiconductor substrates such as silicon wafers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6185432 [Patent Document 2] Patent No. 6348927 [Patent Document 3] Patent No. 6232243 Summary of the Invention [Problem to be solved by the invention]

[0004] The polishing composition used has the polishing ability to efficiently polish the object to be polished. For example, the polishing of semiconductor substrates such as the above-mentioned silicon wafers and other substrates utilizes the mechanical polishing action of abrasive grains and the chemical polishing action (alkaline etching) of basic compounds, and these actions can exert a high processing power. A polishing composition with high processing power can improve production efficiency and cost-effectiveness, and is therefore preferable. In such polishing, the use of silica particles as abrasive grains can efficiently achieve a polished surface with good quality.

[0005] Furthermore, polishing compositions used in polishing the above substrates, such as polishing compositions used in finish polishing processes (particularly finish polishing processes for semiconductor substrates such as silicon wafers and other substrates), are required to have the ability to produce high-quality surfaces after polishing. The surface quality of the polished surface can be improved by incorporating a water-soluble polymer into the polishing composition and using the water-soluble polymer to protect the substrate from alkaline etching. For example, Patent Documents 1 to 3 disclose polishing compositions containing silica particles, a basic compound, and a water-soluble polymer.

[0006] However, depending on their properties, the water-soluble polymers contained in polishing compositions may exert the effect of improving the surface quality after polishing through different mechanisms. For this reason, two or more water-soluble polymers may be contained in a polishing composition in the hope of achieving a synergistic effect or even different effects through combination. However, there is still room for improvement in polishing compositions containing two or more water-soluble polymers in terms of reducing defects (e.g., LPD-N (Light Point Defect Non-cleanable)) and microscratches (e.g., haze lines) and improving the surface quality after polishing.

[0007] Therefore, an object of the present invention is to provide a polishing composition containing at least two types of water-soluble polymers, which is capable of realizing a high-quality surface. [Means for solving the problem]

[0008] According to the present specification, a polishing composition is provided. The polishing composition comprises silica particles (A) as abrasive grains, a basic compound (B), a first water-soluble polymer (C1), a second water-soluble polymer (C2), and water (D). Here, the first water-soluble polymer (C1) is a polyvinyl alcohol-based polymer. The first water-soluble polymer (C1) and the second water-soluble polymer (C2) are selected so that the etching rate ER1 of the first water-soluble polymer (C1) and the etching rate ER2 of the second water-soluble polymer (C2) satisfy the following relationship: 0.6≦ER2 / ER1≦10.

[0009] Here, the etching rate of the water-soluble polymer is an index for evaluating the ability of the water-soluble polymer to protect the surface of the object to be polished from corrosion (etching) by alkali. The etching rate of the water-soluble polymer is determined based on the following etching rate measurement.

[0010] [Etching rate measurement] (1) An etching rate measurement chemical solution LE containing 0.105 mass % of a water-soluble polymer and ammonia, with the remainder being water, and having a pH of 10.4 is prepared. (2) Prepare a silicon single crystal substrate (rectangular, 6 cm long, 3 cm wide, 775 μm thick) that has been immersed in a cleaning solution of NH4OH (29%): H2O2 (31%): deionized water (DIW) = 2:5.3:48 (volume ratio) at 25°C for 1 minute, and then immersed in a hydrogen fluoride (HF) aqueous solution (5%) at 25°C for 30 seconds, and measure its mass W0. (3) Immerse the silicon single crystal substrate in the chemical solution LE at 25°C for 48 hours; (4) Remove the silicon single crystal substrate from the chemical solution LE and wash it for 10 seconds with a cleaning solution of NH4OH (29%): H2O2 (31%): deionized water (DIW) = 1:1:8 (volume ratio) at 25°C; (5) The mass W1 of the silicon single crystal substrate after cleaning is measured. (6) The etching rate [μm / h] is calculated from the difference between W0 and W1 and the specific gravity of the silicon single crystal substrate.

[0011] The polishing composition of the above configuration uses a first water-soluble polymer and a second water-soluble polymer, which have relatively similar performance in protecting the substrate from etching, in combination, and therefore tends to be able to uniformly protect the surface of the silicon wafer to be polished without bias while enjoying the benefits of using two or more water-soluble polymers. By using a polyvinyl alcohol-based polymer as the first water-soluble polymer, the effects of the above configuration can be more appropriately exerted. The polishing composition of the above configuration tends to achieve a high-quality surface with reduced defects (e.g., LPD-N) and microscratches (e.g., haze lines) after polishing.

[0012] In addition, when at least two of the water-soluble polymers contained in the polishing composition are both polyvinyl alcohol-based polymers, the one with the higher etching rate based on the etching rate measurement is deemed to be the first water-soluble polymer (C1), and the one with the lower etching rate based on the etching rate measurement is deemed to be the second water-soluble polymer (C2).

[0013] In some embodiments, the first water-soluble polymer (C1) is at least one selected from the group consisting of unmodified polyvinyl alcohols with a saponification degree of 70% or more, acetalized polyvinyl alcohol-based polymers, and polyvinyl alcohol-based polymers containing repeating units derived from alkyl vinyl ethers. Using such a first water-soluble polymer (C1) together with the second water-soluble polymer (C2) tends to further improve the surface quality after polishing.

[0014] In some embodiments, the content of the first water-soluble polymer (C1) is 0.5 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the abrasive grains. With such a composition, the effects of the technology disclosed herein can be preferably achieved.

[0015] In some embodiments, the second water-soluble polymer (C2) is at least one selected from the group consisting of a polyvinyl alcohol-based polymer having a chemical structure different from that of the first water-soluble polymer (C1), a polymer containing a nitrogen atom, and a polymer containing a (meth)acrylic acid unit. The use of such a second water-soluble polymer (C2) together with the first water-soluble polymer (C1) tends to further improve the surface quality after polishing. In some embodiments, the nitrogen-containing polymer is a polymer containing a chain amide having an N-(meth)acryloyl group as a monomer unit. When such a polymer is used together with the first water-soluble polymer (C1), the surface quality after polishing tends to be further improved.

[0016] In some embodiments, the content of the second water-soluble polymer (C2) is 0.5 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the abrasive grains. With such a composition, the effects of the technology disclosed herein can be preferably achieved.

[0017] In some embodiments, the polishing composition further contains a surfactant (E). Such a configuration tends to further improve the surface quality after polishing. In a preferred embodiment, the surfactant (E) is a nonionic surfactant.

[0018] The polishing composition disclosed herein can be preferably used for polishing a surface made of a silicon material. By polishing a surface made of a silicon material with the polishing composition, a high-quality surface made of a silicon material can be efficiently achieved. The polishing composition disclosed herein can be a concentrate. The polishing composition disclosed herein can be manufactured, distributed, and stored as a concentrate. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described below. It should be noted that matters necessary for carrying out the present invention other than those specifically mentioned in this specification can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The present invention can be carried out based on the contents disclosed in this specification and the common general technical knowledge in the relevant field.

[0020] <Abrasive grain> The polishing composition disclosed herein contains silica particles as abrasive grains. The silica particles as abrasive grains function to mechanically polish the surface of the object to be polished. By including abrasive grains in the polishing composition, the polishing rate can be improved due to the mechanical polishing action of the abrasive grains. Furthermore, in polishing compositions that can be used for polishing (e.g., finish polishing) objects having a silicon surface, such as silicon wafers, as described below, it is particularly meaningful to use silica particles as abrasive grains.

[0021] Specific examples of silica particles include colloidal silica, fumed silica, precipitated silica, etc. Silica particles can be used alone or in combination of two or more types. Colloidal silica is particularly preferred because it is easy to obtain a polished surface with excellent surface quality after polishing. As colloidal silica, for example, colloidal silica produced by an ion exchange method using water glass (sodium silicate) as a raw material, or alkoxide method colloidal silica (colloidal silica produced by the hydrolysis and condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used alone or in combination of two or more types.

[0022] The true specific gravity of the silica constituting the silica particles 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 the silica particles can be measured by a liquid substitution method using ethanol as a substitution liquid.

[0023] The average primary particle size of the abrasive grains (typically silica particles) is not particularly limited, but from the viewpoint of polishing rate, etc., it is preferably 5 nm or more, more preferably 10 nm or more. From the viewpoint of obtaining a higher polishing effect (e.g., effects such as haze reduction and defect removal), the average primary particle size is preferably 15 nm or more, more preferably 20 nm or more (e.g., more than 20 nm). Furthermore, from the viewpoint of scratch prevention, etc., the average primary particle size of the abrasive grains is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 45 nm or less. From the viewpoint of easily obtaining a surface with lower haze, in some embodiments, the average primary particle size of the abrasive grains may be 43 nm or less, or may be less than 40 nm, less than 38 nm, less than 35 nm, less than 32 nm, or less than 30 nm.

[0024] In this specification, the average primary particle size is calculated from the specific surface area (BET value) measured by the BET method as follows: average primary particle size (nm) = 6000 / (true density (g / cm 3 )×BET value(m 2 / g) The specific surface area can be measured using, for example, a surface area measuring device manufactured by Micromeritics, under the trade name "Flow Sorb II 2300."

[0025] The average secondary particle diameter of the abrasive grains (typically silica particles) is not particularly limited and can be appropriately selected, for example, from a range of about 15 nm to 300 nm. From the viewpoint of improving the polishing rate, the average secondary particle diameter is preferably 30 nm or more, more preferably 35 nm or more. In some embodiments, the average secondary particle diameter may be, for example, 40 nm or more, 42 nm or more, or preferably 44 nm or more. Furthermore, the average secondary particle diameter is usually advantageously 250 nm or less, preferably 200 nm or less, and more preferably 150 nm or less. In some preferred embodiments, the average secondary particle diameter is 120 nm or less, more preferably 100 nm or less, even more preferably 70 nm or less, for example, 60 nm or less, or may be 50 nm or less.

[0026] In this specification, the average secondary particle size refers to the particle size (volume average particle size) measured by dynamic light scattering. The average secondary particle size of the abrasive grains can be measured by dynamic light scattering using, for example, a product named "Nanotrac UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0027] The shape (external shape) of the silica particles may be spherical or non-spherical. Specific examples of non-spherical particles include peanut-shaped (i.e., peanut shell-shaped), cocoon-shaped, confetti-shaped, and rugby ball-shaped. For example, silica particles in which most of the particles are peanut-shaped or cocoon-shaped can be preferably used.

[0028] Although not particularly limited, the average value of the long diameter / short diameter ratio (average aspect ratio) of the silica particles is, in principle, 1.0 or more, preferably 1.05 or more, more preferably 1.1 or more, and may be 1.2 or more. By increasing the average aspect ratio, a higher polishing rate can be achieved. Furthermore, from the viewpoint of reducing scratches, the average aspect ratio of the silica particles is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and may be 1.4 or less.

[0029] The shape (external shape) and average aspect ratio of silica particles can be determined, for example, by electron microscope observation. A specific procedure for determining the average aspect ratio involves, for example, using a scanning electron microscope (SEM), drawing the smallest rectangle circumscribing each particle image for a predetermined number (e.g., 200) of silica particles whose individual particle shapes can be recognized. Then, for each rectangle drawn for each particle image, the long side length (long diameter value) is divided by the short side length (short diameter value) to calculate the long diameter / short diameter ratio (aspect ratio). The average aspect ratio can be determined by arithmetically averaging the aspect ratios of the predetermined number of particles.

[0030] The polishing composition disclosed herein may contain abrasive particles other than silica particles (hereinafter also referred to as "non-silica abrasive particles"), provided that the effects of the present invention are not significantly impaired. Examples of non-silica abrasive particles include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include oxide particles such as alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and red iron oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; and carbonates such as calcium carbonate and barium carbonate. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles (here, "(meth)acrylic acid" refers collectively to acrylic acid and methacrylic acid), and polyacrylonitrile particles. These abrasive particles may be used singly or in combination of two or more.

[0031] The technology disclosed herein can be preferably implemented in an embodiment using substantially only silica particles as abrasive grains. From this viewpoint, the proportion of silica particles in the total amount of abrasive grains is 90% by weight or more, preferably 95% by weight or more, and more preferably 98% by weight or more (e.g., 99 to 100% by weight).

[0032] <Basic compounds> The polishing composition disclosed herein contains a basic compound. In this specification, a basic compound refers to a compound that dissolves in water and increases the pH of the aqueous solution. By incorporating a basic compound into the polishing composition, the object to be polished can be efficiently polished by its chemical polishing action (alkaline etching). Examples of basic compounds that can be used include organic or inorganic basic compounds containing nitrogen, basic compounds containing phosphorus, alkali metal hydroxides, alkaline earth metal hydroxides, various carbonates and hydrogen carbonates, etc. Examples of nitrogen-containing basic compounds include quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), etc. Examples of phosphorus-containing basic compounds include quaternary phosphonium compounds. These basic compounds can be used alone or in combination of two or more.

[0033] Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, and sodium carbonate. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole. Specific examples of quaternary phosphonium compounds include quaternary phosphonium hydroxides such as tetramethylphosphonium hydroxide and tetraethylphosphonium hydroxide.

[0034] As the quaternary ammonium compound, a quaternary ammonium salt (typically a strong base) such as a tetraalkylammonium salt or a hydroxyalkyltrialkylammonium salt can be used. The anion component in such a quaternary ammonium salt is, for example, OH - , F- , Cl - , Br - , I - , ClO4 - , BH4 - and the like. Examples of the quaternary ammonium compounds include quaternary ammonium salts whose anion is OH-, i.e., quaternary ammonium hydroxides. Specific examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide; hydroxyalkyltrialkylammonium hydroxides such as 2-hydroxyethyltrimethylammonium hydroxide (also called choline); and the like.

[0035] Among these basic compounds, at least one basic compound selected from, for example, alkali metal hydroxides, quaternary ammonium hydroxides, and ammonia can be preferably used. Among these, tetraalkylammonium hydroxides (e.g., tetramethylammonium hydroxide) and ammonia are more preferred, and ammonia is particularly preferred.

[0036] <Water-soluble polymer> The polishing composition disclosed herein contains a water-soluble polymer. The water-soluble polymer can be useful for protecting the surface to be polished and improving the wettability of the surface to be polished after polishing. The polishing composition disclosed herein is characterized by containing at least two water-soluble polymers that satisfy specific conditions regarding the protective performance of the surface to be polished against etching (substrate protection). That is, the polishing composition disclosed herein contains a first water-soluble polymer and a second water-soluble polymer, and the etching rate ER1 of the first water-soluble polymer and the etching rate ER2 of the second water-soluble polymer satisfy specific conditions. Herein, the etching rate of the water-soluble polymer is determined based on a predetermined etching rate measurement shown below. The same applies to the examples described below.

[0037] [Etching rate measurement] (1) An etching rate measurement chemical solution LE containing 0.105 mass % of a water-soluble polymer and ammonia, with the remainder being water, and having a pH of 10.4 is prepared. (2) Prepare a silicon single crystal substrate (rectangular, 6 cm long, 3 cm wide, 775 μm thick) that has been immersed in a cleaning solution of NH4OH (29%): H2O2 (31%): deionized water (DIW) = 2:5.3:48 (volume ratio) at 25°C for 1 minute, and then immersed in a hydrogen fluoride (HF) aqueous solution (5%) at 25°C for 30 seconds, and measure its mass W0. (3) The silicon single crystal substrate is immersed in the chemical solution LE at room temperature for 48 hours. (4) The silicon single crystal substrate is removed from the chemical solution LE and washed for 10 seconds with a cleaning solution of NH4OH (29%): H2O2 (31%): deionized water (DIW) = 1:1:8 (volume ratio) at 25°C. (5) The mass W1 of the silicon single crystal substrate after cleaning is measured. (6) The etching rate [μm / h] is calculated from the difference between W0 and W1 and the specific gravity of the silicon single crystal substrate.

[0038] The etching rate based on the above-mentioned predetermined etching rate measurement can be an index for evaluating the ability of the water-soluble polymer to protect the surface of the object to be polished from corrosion by alkali under conditions excluding the influence of the mechanical action of abrasive grains, and depends on the properties of the water-soluble polymer. A lower etching rate tends to indicate a higher ability of the water-soluble polymer to adsorb to the surface of the object to be polished and to prevent the surface from being chemically etched by a basic compound or the like, i.e., a higher ability to protect the surface of the object to be polished.

[0039] The polishing composition disclosed herein is characterized by containing two water-soluble polymers with relatively similar etching rates. That is, the first water-soluble polymer and the second water-soluble polymer have relatively similar substrate protection performance. A polishing composition containing such two water-soluble polymers can protect the surface of an object to be polished uniformly without bias, and therefore tends to achieve a high-quality surface with reduced defects (e.g., LPD-N) and microscratches (e.g., haze lines) after polishing.

[0040] In a preferred embodiment of the technology disclosed herein, the ratio (ER2 / ER1) of the etching rate ER1 [μm / h] of the first water-soluble polymer to the etching rate ER2 [μm / h] of the second water-soluble polymer is 0.6 or more and 10 or less. When the etching rate ratio (ER2 / ER1) is in the above range, the substrate protection performance of the first water-soluble polymer and the second water-soluble polymer are relatively similar, and therefore, a high-quality surface with reduced defects (e.g., LPD-N) and micro-scratches (e.g., haze lines) after polishing tends to be achieved.

[0041] From the viewpoint of realizing a high-quality surface while enjoying the benefits of using two types of water-soluble polymers in combination, in a more preferred embodiment, the etching rate ratio (ER2 / ER1) is 0.7 or more, even more preferably 0.8 or more, and particularly preferably 0.9 or more. In some embodiments, the etching rate ratio (ER2 / ER1) may be 1.0 or more, or may be 1.5 or more. Furthermore, from the viewpoint of realizing a high-quality surface, in a preferred embodiment, the etching rate ratio (ER2 / ER1) is 8.0 or less, may be 6.0 or less, may be 4.0 or less, may be 3.0 or less, or may be 2.0 or less.

[0042] The etching rate of the water-soluble polymer can be controlled by the type, molecular weight, etc. of the water-soluble polymer.

[0043] <First water-soluble polymer> The polishing composition disclosed herein contains a polyvinyl alcohol-based polymer as a first water-soluble polymer. A polishing composition containing a polyvinyl alcohol-based polymer is likely to produce a high-quality polished surface. While not intended to be particularly restrictive, it is believed that the polyvinyl alcohol-based polymer acts on the substrate surface to protect it, thereby contributing to improved polished surface quality (specifically, reduced haze). By using a polyvinyl alcohol-based polymer as the first water-soluble polymer in combination with a second water-soluble polymer, it is possible to effectively achieve high surface quality while enjoying the benefits of the different actions of each water-soluble polymer.

[0044] In this specification, a polyvinyl alcohol-based polymer refers to a polymer containing vinyl alcohol units (hereinafter also referred to as "VA units") as its repeating units. One type of polyvinyl alcohol-based polymer may be used alone, or two or more types may be used in combination. A polyvinyl alcohol-based polymer may contain only VA units as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units"). A polyvinyl alcohol-based polymer may be a random copolymer containing VA units and non-VA units, or may be a block copolymer, an alternating copolymer, or a graft copolymer. A polyvinyl alcohol-based polymer may contain only one type of non-VA unit, or may contain two or more types of non-VA units.

[0045] The polyvinyl alcohol-based polymer may be either unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA). Unmodified PVA refers to a polyvinyl alcohol-based polymer produced by hydrolysis (saponification) of polyvinyl acetate, which is substantially free of repeating units other than repeating units (—CH—CH(OCOCH)—) formed by vinyl polymerization of vinyl acetate and VA units. The degree of saponification of the unmodified PVA may be, for example, 60% or more, and from the viewpoint of water solubility, may be 70% or more, 80% or more, or 90% or more. In some embodiments, the degree of saponification of the unmodified PVA may be 98% or more (complete saponification).

[0046] The polyvinyl alcohol polymer may be a modified PVA containing VA units and non-VA units having at least one structure selected from oxyalkylene groups, carboxy groups, (di)carboxylic acid groups, (di)carboxylic acid ester groups, phenyl groups, naphthyl groups, sulfo groups, amino groups, hydroxyl groups, amide groups, imide groups, nitrile groups, ether groups, ester groups, and salts thereof. Non-VA units that may be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl monomers or N-(meth)acryloyl monomers, as described below, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, and repeating units derived from (di)acetone compounds. A preferred example of the N-vinyl monomer is N-vinylpyrrolidone. A preferred example of the N-(meth)acryloyl monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be a vinyl ether having an alkyl group having from 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 from 3 to 7 carbon atoms may be a vinyl ester of a monocarboxylic acid having from 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.

[0047] In some preferred embodiments, an acetalized polyvinyl alcohol polymer is used as the polyvinyl alcohol polymer. An example of an acetalized polyvinyl alcohol polymer is a modified PVA in which some of the VA units contained in the polyvinyl alcohol polymer have been acetalized. The modified PVA in which some of the VA units contained in the polyvinyl alcohol polymer have been acetalized (acetalized PVA (ac-PVA)) can be obtained by reacting some of the hydroxy groups of the polyvinyl alcohol polymer with an aldehyde compound or a ketone compound to acetalize the polymer. Typically, the acetalized polyvinyl alcohol polymer is obtained by the acetalization reaction of a polyvinyl alcohol polymer with an aldehyde compound. In some preferred embodiments, the aldehyde compound has 1 to 7 carbon atoms, more preferably 2 to 7 carbon atoms.

[0048] Examples of the aldehyde compound include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butylaldehyde, isobutyraldehyde, t-butylaldehyde, and hexylaldehyde; and alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde. These may be used alone or in combination of two or more. Except for formaldehyde, one or more hydrogen atoms may be substituted with a halogen or the like. Among these, linear or branched alkyl aldehydes are preferred because of their high solubility in water and ease of acetalization reaction, and among these, acetaldehyde, n-propylaldehyde, n-butylaldehyde, and n-pentylaldehyde are more preferred.

[0049] In addition to the above, aldehyde compounds having 8 or more carbon atoms, such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde, may also be used as the aldehyde compound.

[0050] The acetalized polyvinyl alcohol polymer contains VA units, which are structural moieties represented by the following chemical formula: -CH-CH(OH)-; and acetalized structural units (hereinafter also referred to as "VAC units") represented by the following general formula (1).

[0051] [ka] (In formula (1), R is a hydrogen atom or a linear or branched alkyl group, and the alkyl group may be substituted with a functional group.)

[0052] In some preferred embodiments, R in the above formula (1) is a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. R may be one of these groups or a combination of two or more of these groups. From the viewpoint of improving haze reduction performance, R is preferably a linear or branched alkyl chain having 1 to 6 carbon atoms.

[0053] From the viewpoint of improving haze reduction performance, the acetalization degree of the acetalized polyvinyl alcohol-based polymer can be 1 mol% or more, or may be 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more (e.g., 27 mol% or more). From the viewpoint of improving hydrophilicity, the acetalization degree of the acetalized polyvinyl alcohol-based polymer is preferably less than 60 mol%, even more preferably 50 mol% or less, more preferably 40 mol% or less, and particularly preferably 35 mol% or less (e.g., 33 mol% or less). In this specification, the "acetalization degree" refers to the proportion of acetalized structural units (VAC units) in all repeating units constituting the acetalized polyvinyl alcohol-based polymer.

[0054] Furthermore, 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. Examples of the cation-modified polyvinyl alcohol include those into which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, has been introduced. Furthermore, as the vinyl alcohol-based polymer, a non-VA unit having the chemical formula: -CH2-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, and R 4 and R 5 are each independently a hydrogen atom or R 6 -CO-(wherein, R 6 represents 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 alkyl group having from 1 to 8 carbon atoms.

[0055] In some embodiments, the modified PVA used is a modified PVA having a 1,2-diol structure in the side chain. 1 ~R 5 A modified PVA (butenediol-vinyl alcohol copolymer (BVOH)) containing non-VA units in which .alpha. is a hydrogen atom can be preferably used.

[0056] The proportion of moles of VA units to the total number of moles of 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. While not particularly limited, in some embodiments, the proportion of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100%" means that the polyvinyl alcohol-based polymer does not, at least intentionally, contain non-VA units. Typically, the proportion of moles of non-VA units to the total number of moles of repeating units is less than 2% (e.g., less than 1%), including 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0057] The content of VA units in the polyvinyl alcohol-based polymer (content by weight) may be, for example, 5% by weight or more, 10% by weight or more, 20% by weight or more, or 30% by weight or more. While not particularly limited, in some embodiments, the content of VA units may be 50% by weight or more (e.g., more than 50% by weight), 70% by weight or more, or 80% by weight or more (e.g., 90% by weight or more, 95% by weight or more, or 98% by weight or more). Substantially 100% by weight of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100% by weight" means that non-VA units are not, at least intentionally, included as repeating units constituting the polyvinyl alcohol-based polymer, and typically means that the content of non-VA units in the polyvinyl alcohol-based polymer is less than 2% by weight (e.g., less than 1% by weight). In some other embodiments, the content of VA units in the polyvinyl alcohol-based polymer may be, for example, 95% by weight or less, 90% by weight or less, 80% by weight or less, or 70% by weight or less.

[0058] A polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit contents within the same molecule. Here, a polymer chain refers to a segment that constitutes part of a single polymer molecule. For example, a polyvinyl alcohol-based polymer may contain, within the same molecule, polymer chain A with a VA unit content of more than 50% by weight and polymer chain B with a VA unit content of less than 50% by weight (i.e., a non-VA unit content of more than 50% by weight).

[0059] The polymer chain A may contain only VA units as repeating units, or may contain non-VA units in addition to VA units. The content of VA units in the polymer chain A 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 VA units in the polymer chain A may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting the polymer chain A may be VA units.

[0060] Polymer chain B may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units. The content of non-VA units in 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 polymer chain B may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting polymer chain B may be non-VA units.

[0061] 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 some embodiments, a polyvinyl alcohol-based polymer having a structure in which polymer chain B is grafted to polymer chain A can be used.

[0062] Examples of polymer chain B include polymer chains having a repeating unit derived from an N-vinyl type monomer as the main repeating unit, polymer chains having a repeating unit derived from an N-(meth)acryloyl type monomer as the main repeating unit, polymer chains having a repeating unit derived from a vinyl dicarboxylate such as fumaric acid, maleic acid, or maleic anhydride as the main repeating unit, polymer chains having a repeating unit derived from an aromatic vinyl monomer such as styrene or vinylnaphthalene as the main repeating unit, and polymer chains having an oxyalkylene unit as the main repeating unit. In this specification, the term "main repeating unit" refers to a repeating unit contained in an amount of more than 50% by weight, unless otherwise specified.

[0063] A suitable example of the polymer chain B is a polymer chain having an N-vinyl monomer as the main repeating unit, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl monomers in the N-vinyl polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of the polymer chain B may be repeating units derived from N-vinyl monomers.

[0064] In this specification, examples of N-vinyl monomers include monomers having a nitrogen-containing heterocycle (e.g., a lactam ring) and N-vinyl linear amides. Specific examples of N-vinyl lactam monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione. Specific examples of N-vinyl linear amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. Polymer chain B may be, for example, an N-vinyl polymer chain in which more than 50% by weight (e.g., 70% by weight or more, 85% by weight or more, or 95% by weight or more) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinylpyrrolidone units.

[0065] Another example of polymer chain B is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl-type monomer, i.e., an N-(meth)acryloyl-based polymer chain. The content of repeating units derived from N-(meth)acryloyl-type monomers in the N-(meth)acryloyl-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of polymer chain B may be repeating units derived from N-(meth)acryloyl-type monomers.

[0066] In this specification, examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0067] 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 weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of the repeating units contained in the polymer chain B may be oxyalkylene units.

[0068] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be a repeating unit derived from the corresponding alkylene oxide. The oxyalkylene unit contained in the oxyalkylene polymer chain may be one type or two or more types. For example, the oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, the oxyalkylene units may be a random copolymer, block copolymer, alternating copolymer, or graft copolymer of the corresponding alkylene oxide.

[0069] Further examples of polymer chain B include a polymer chain 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), and a polymer chain into which a cationic group (e.g., a cationic group having a quaternary ammonium structure) has been introduced.

[0070] In some embodiments of the technology disclosed herein, the polyvinyl alcohol-based polymer serving as the first water-soluble polymer is preferably a modified polyvinyl alcohol, which is a copolymer containing VA units and non-VA units. The degree of saponification of the modified polyvinyl alcohol-based polymer serving as the first water-soluble polymer is usually 50 mol% or more, preferably 65 mol% or more, more preferably 70 mol% or more, for example, 75 mol% or more.

[0071] The weight average molecular weight (Mw) of the first water-soluble polymer (specifically, the polyvinyl alcohol polymer) is, for example, 100×10 4 It can be 60 x 10 4 From the viewpoint of concentration efficiency, the above Mw is 30 × 10 4or less, preferably 20×10 4 For example, 10 x 10 4 May be less than 8 x 10 4 Less than 5 x 10 is fine. 4 Less than 3 x 10 is also acceptable. 4 As the Mw of the polyvinyl alcohol-based polymer decreases, the dispersion stability of the polyvinyl alcohol-based polymer tends to improve. In addition, from the viewpoint of favorably protecting the polishing surface and maintaining or improving the surface quality, the Mw may be, for example, 0.2 × 10 4 It can be more than 0.5 × 10 4 As the Mw of the polyvinyl alcohol-based polymer increases, the effect of protecting the object to be polished and improving the wettability tends to increase. From this viewpoint, in some embodiments, the Mw is 0.8 × 10 4 The above is appropriate, and preferably 1.0 × 10 4 That's 2 x 10 4 May be greater than 3 x 10 4 More than this is acceptable, for example, 4×10 4 More than 5 x 10 is also fine. 4 More than that is fine.

[0072] The Mw of the water-soluble polymer can be calculated from a value based on aqueous gel permeation chromatography (GPC) (aqueous, polyethylene oxide equivalent). The same applies to the Mw of the first water-soluble polymer described above and the second water-soluble polymer described below. A GPC measuring device such as "HLC-8320GPC" manufactured by Tosoh Corporation can be used. Measurements can be performed, for example, under the following conditions. Similar methods are also used in the examples described below. [GPC measurement conditions] Sample concentration: 0.1% by weight Column: TSKgel GMPW XL Detector: differential refractometer Eluent: 100mM sodium nitrate aqueous solution Flow rate: 1mL / min Measurement temperature: 40℃ Sample injection volume: 200 μL

[0073] The etching rate ER1 of the first water-soluble polymer (specifically, a vinyl alcohol-based alcohol) is not particularly limited as long as it satisfies the above-mentioned specific conditions in relation to the etching rate ER2 of the second water-soluble polymer. In some embodiments, from the viewpoint of substrate protection, the etching rate ER1 of the first water-soluble polymer is 10 nm / h It is preferable that the number is 5 or less, and more preferably 5 nm / h More preferably, 4 nm / h is less than or equal to 3.5 nm / h From the viewpoint of improving the polishing rate, the etching rate ER1 of the first water-soluble polymer is usually 1.0 or less. nm / h It is suitable that the ratio is equal to or greater than 1.5, preferably 1.5 nm / h More preferably, it is 1.8 nm / h More preferably, it is 2.0 nm / h In some embodiments, the etching rate ER1 of the first water-soluble polymer is 2.5 or more. nm / h It may be 2.8 or more. nm / h More than that is fine.

[0074] Although not particularly limited, in some embodiments, the content of the first water-soluble polymer (specifically, a polyvinyl alcohol-based polymer) in the polishing composition can be, for example, 0.01 parts by weight or more relative to 100 parts by weight of abrasive grains (typically silica particles). From the viewpoint of defect reduction, etc., it is appropriate to set it to 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and may be 1.5 parts by weight or more, 2 parts by weight or more, 3 parts by weight or more, or even 3.5 parts by weight or more. The content of the first water-soluble polymer relative to 100 parts by weight of abrasive grains may be, for example, 50 parts by weight or less, or may be 30 parts by weight or less. From the viewpoint of dispersion stability of the polishing composition, etc., in some embodiments, the content of the first water-soluble polymer relative to 100 parts by weight of abrasive grains is appropriate to be 15 parts by weight or less, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and may be less than 3 parts by weight, 2.5 parts by weight or less, or may be 2 parts by weight or less. By appropriately setting the amount of the first water-soluble polymer (specifically, polyvinyl alcohol-based polymer) used within the above range, high surface quality can be achieved after polishing.

[0075] <Second water-soluble polymer> The polishing composition disclosed herein contains a second water-soluble polymer in addition to a first water-soluble polymer (specifically, a polyvinyl alcohol-based polymer). The second water-soluble polymer is typically a polymer having a different chemical structure from the first water-soluble polymer. The second water-soluble polymer is not particularly limited, and various types may be used, as long as it satisfies the above-mentioned specific conditions regarding the first water-soluble polymer and the etching rate.

[0076] Examples of the second water-soluble polymer include compounds containing, in the molecule, a hydroxyl group, a carboxyl group, an acyloxy group, a sulfo group, an amide structure, an imide structure, a quaternary ammonium structure, a heterocyclic structure, a vinyl structure, etc. Examples of the second water-soluble polymer that can be used include cellulose derivatives, starch derivatives, polymers containing oxyalkylene units, polyvinyl alcohol polymers, polymers containing nitrogen atoms, and polymers containing (meth)acrylic acid units. Examples of the nitrogen-containing polymer that can be used include N-vinyl polymers and N-(meth)acryloyl polymers. The second water-soluble polymer may be a polymer derived from a natural product or a synthetic polymer.

[0077] In some embodiments, the second water-soluble polymer is a polymer derived from natural products, such as cellulose derivatives and starch derivatives.

[0078] In some embodiments, a cellulose derivative is used as the second water-soluble polymer. Here, the cellulose derivative is a polymer containing β-glucose units as the main repeating unit. Specific examples of cellulose derivatives include hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose. Among these, HEC is preferred.

[0079] In some other embodiments, the second water-soluble polymer is a starch derivative, which is a polymer containing α-glucose units as the main repeating unit, such as pregelatinized starch, pullulan, carboxymethyl starch, and cyclodextrin.

[0080] In some other preferred embodiments, a synthetic polymer is used as the second water-soluble polymer. The surface quality improving effect disclosed herein is preferably exhibited in embodiments in which a synthetic polymer is used as the second water-soluble polymer.

[0081] In some embodiments, a polymer containing an oxyalkylene unit is used as the second water-soluble polymer. Examples of polymers containing an oxyalkylene unit include polyethylene oxide (PEO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO. Among these, block copolymers of EO and PO or random copolymers of EO and PO are preferred. The block copolymer of EO and PO may be a diblock copolymer containing a PEO block and a polypropylene oxide (PPO) block, or a triblock copolymer. Examples of the triblock copolymer include PEO-PPO-PEO triblock copolymers and PPO-PEO-PPO triblock copolymers. PEO-PPO-PEO triblock copolymers are usually more preferred.

[0082] In this specification, unless otherwise specified, the term "copolymer" refers collectively to various copolymers such as random copolymers, alternating copolymers, block copolymers, and graft copolymers.

[0083] In a block copolymer or random copolymer of EO and PO, the molar ratio of EO to PO (EO / PO) constituting the copolymer is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more (e.g., 5 or more), from the viewpoints of solubility in water, washability, etc.

[0084] In some preferred embodiments, a polyvinyl alcohol-based polymer is used as the second water-soluble polymer. When the polishing composition contains two or more vinyl alcohol-based polymers, the one with a higher etching rate based on the etching rate measurement is the first water-soluble polymer, and the one with a lower etching rate based on the etching rate measurement is the second water-soluble polymer.

[0085] As the polyvinyl alcohol-based polymer for the second water-soluble polymer, those listed as polymers that can be preferably used as the first water-soluble polymer can be preferably used. In a preferred embodiment, the second water-soluble polymer can be a modified PVA containing repeating units derived from N-vinyl type monomers or N-(meth)acryloyl type monomers as non-VA units. In other embodiments, a description of polyvinyl alcohol-based polymers that can be preferably used as the second water-soluble polymer will be omitted to avoid redundancy.

[0086] In some other embodiments, an N-vinyl polymer can be used as the second water-soluble polymer. Examples of N-vinyl polymers include polymers containing repeating units derived from monomers having a nitrogen-containing heterocycle (e.g., lactam ring). Examples of such polymers include homopolymers and copolymers of N-vinyl lactam monomers (e.g., copolymers containing more than 50% by weight of N-vinyl lactam monomers), homopolymers and copolymers of N-vinyl linear amides (e.g., copolymers containing more than 50% by weight of N-vinyl linear amides), and the like.

[0087] Specific examples of N-vinyl lactam monomers (i.e., compounds having a lactam structure and an N-vinyl group in one molecule) include N-vinylpyrrolidone (VP), N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam (VC), N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, etc. Specific examples of polymers containing N-vinyl lactam 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, alternating copolymers, and graft copolymers containing polymer chains containing one or both of VP and VC. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide.

[0088] In some other embodiments, an N-(meth)acryloyl polymer may be used as the second water-soluble polymer. Examples of N-(meth)acryloyl polymers include homopolymers and copolymers of N-(meth)acryloyl monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl monomers exceeds 50% by weight). Examples of N-(meth)acryloyl monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. In this specification, the term "(meth)acryloyl" refers to both acryloyl and methacryloyl groups. In this specification, the term "(meth)acryloyl group" refers to both acryloyl and methacryloyl groups.

[0089] Examples of linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Other examples include N-hydroxyethylacrylamide (HEAA). Examples of polymers containing linear amides having an N-(meth)acryloyl group as a monomer unit include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (e.g., copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by weight). In this specification, the term "(meth)acrylamide" refers to acrylamide and methacrylamide inclusively.

[0090] 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 (PACMO). Typical examples of acryloylmorpholine-based polymers include homopolymers of N-acryloylmorpholine (ACMO) and copolymers of ACMO (e.g., copolymers with a copolymerization ratio of ACMO exceeding 50% by weight). In acryloylmorpholine-based polymers, the proportion of moles of ACMO units in the total moles of repeating units is typically 50% or more, and suitably 80% or more (e.g., 90% or more, typically 95% or more). All repeating units of the second water-soluble polymer may consist essentially of ACMO units.

[0091] In some embodiments, a carboxylic acid polymer is used as the second water-soluble polymer. Examples of carboxylic acid polymers include polymers containing maleic acid units and polymers containing (meth)acrylic acid units. Examples of polymers containing maleic acid units include styrene-maleic acid copolymers or salts thereof, styrene-maleic anhydride copolymers, styrene sulfonic acid-maleic acid copolymers or salts thereof, copolymers of styrene sulfonate and maleic acid, and maleic acid-vinyl acetate copolymers. Examples of polymers containing (meth)acrylic acid units include polyacrylic acid or salts thereof, styrene-acrylic acid copolymers or salts thereof, styrene sulfonic acid-acrylic acid copolymers or salts thereof, copolymers of styrene sulfonate and acrylic acid, acrylic acid-vinyl acetate copolymers, and acrylic acid / sulfonic acid monomer copolymers. In this specification, (meth)acrylic acid is a comprehensive term referring to acrylic acid and methacrylic acid.

[0092] When the second water-soluble polymer is a polyvinyl alcohol-based polymer, the Mw of the second water-soluble polymer is, for example, 100 × 10 4 It can be 60 x 10 4 From the viewpoint of concentration efficiency, the above Mw is 30 × 10 4 or less, preferably 20×10 4 For example, 10 x 10 4 May be less than 8 x 10 4 Less than 5 x 10 is fine. 4 Less than 3 x 10 is also acceptable. 4 In order to protect the polished surface and maintain or improve the surface quality, the Mw may be, for example, 0.2 × 10 4 It can be more than 0.5 × 10 4 As the Mw of the polyvinyl alcohol-based polymer increases, the effect of protecting the object to be polished and improving the wettability tends to increase. From this viewpoint, in some embodiments, the Mw is 0.8 × 10 4 The above is appropriate, and preferably 1.0 × 10 4 That is 1.2 x 10 4 It may be more than that.

[0093] When the second water-soluble polymer is a polymer containing a chain amide having an N-(meth)acryloyl group as a monomer unit, the Mw of the second water-soluble polymer is, for example, 100 × 10 4 It can be 50 x 10 4 From the viewpoint of concentration efficiency, the above Mw is 30 × 10 4 It may be less than 10 x 10 4 Less than 8 x 10 is fine. 4 Less than 6×10 is also acceptable. 4 From the viewpoint of improving the surface quality, the Mw may be, for example, 1×10 4 May be greater than 2 x 10 4 More than 3 x 10 is also acceptable. 4 or more (e.g., 4×10 4By using a second water-soluble polymer with a high Mw, high surface quality is likely to be obtained.

[0094] When the second water-soluble polymer is a polymer containing a cyclic amide having an N-(meth)acryloyl group as a monomer unit, the Mw of the second water-soluble polymer is, for example, 100 × 10 4 It can be 70 x 10 4 From the viewpoint of concentration efficiency, the above Mw is 60 × 10 4 It may be less than 50 x 10 4 Less than 35 x 10 is also acceptable. 4 Less than 35 x 10 is also acceptable. 4 It can be less than 30 x 10 4 Less than 20 x 10 is fine. 4 From the viewpoint of improving the surface quality, the Mw may be, for example, 1.0×10 4 May be more than 5 x 10 4 More than 10 x 10 is fine. 4 or more (e.g., 10 x 10 4 By using a second water-soluble polymer with a high Mw, high surface quality is likely to be obtained.

[0095] When the second water-soluble polymer is a polymer containing a (meth)acrylic acid unit, the Mw of the second water-soluble polymer is, for example, 800 × 10 4 It can be 500 x 10 4 From the viewpoint of concentration efficiency, the above Mw is 300 × 10 4 or less, preferably 200×10 4 For example, 175 x 10 4 It may be less than 150 x 10 4 Less than 140 x 10 is also acceptable. 4 In order to protect the polished surface and maintain or improve the surface quality, the Mw may be, for example, 20×10 4 It may be 50 x 10 or more. 4 More than 100 x 10 4 or more (e.g., 130 x 10 4By using a second water-soluble polymer with a high Mw, high surface quality is likely to be obtained.

[0096] When the second water-soluble polymer is a polymer containing an oxyalkylene unit, the Mw of the second water-soluble polymer is 10 × 10 4 It can be 5 x 10 4 Less than 3 x 10 is also acceptable. 4 Less than 2×10 is also acceptable. 4 The above Mw may be 1×10 4 It can be more than 1.2 x 10 4 More than 1.5 x 10 4 More than that is fine.

[0097] Although not particularly limited, in some embodiments, the second water-soluble polymer may preferably have a higher Mw than the first water-soluble polymer. By using two water-soluble polymers with the above-mentioned relative Mw, high surface quality after polishing can be preferably achieved.

[0098] The etching rate ER2 of the second water-soluble polymer is not particularly limited as long as it satisfies the above-mentioned specific conditions in relation to the etching rate ER1 of the first water-soluble polymer. In some embodiments, from the viewpoint of substrate protection, the etching rate ER2 of the second water-soluble polymer is, for example, 20 nm / h It can be 15 or less. nm / h Preferably, it is 10 or less. nm / h It is more preferable that it is 5 or less, and even more preferable that it is 5 or less. nm / h It is particularly preferably 4 nm / h is less than or equal to 3.5 nm / h From the viewpoint of improving the polishing rate, the etching rate ER2 of the second water-soluble polymer is usually 1.0 or less. nm / h It is suitable that the ratio is equal to or greater than 1.5, preferably 1.5 nm / h More preferably, it is 1.8 nm / h More preferably, it is 2.0 nm / hIn some embodiments, the etching rate ER2 of the second water-soluble polymer is 2.4 or more. nm / h It may be 2.8 or more. nm / h More than that is fine.

[0099] Although not particularly limited, in some embodiments, the content of the second water-soluble polymer in the polishing composition can be, for example, 0.01 parts by weight or more relative to 100 parts by weight of abrasive grains (typically silica particles). From the viewpoint of reducing haze, etc., it is appropriate to set it to 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and may even be 2 parts by weight or more. Furthermore, the content of the second water-soluble polymer relative to 100 parts by weight of abrasive grains may be, for example, 50 parts by weight or less, or may even be 30 parts by weight or less. From the viewpoint of dispersion stability of the polishing composition, etc., in some embodiments, the content of the second water-soluble polymer relative to 100 parts by weight of abrasive grains is appropriate to be 15 parts by weight or less, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and may even be, for example, 3.5 parts by weight or less. By appropriately setting the amount of the second water-soluble polymer used within the above range, high surface quality can be obtained.

[0100] Although not particularly limited, in some embodiments, the total content of the water-soluble polymers contained in the polishing composition can be, for example, 0.01 parts by weight or more per 100 parts by weight of abrasive grains (typically silica particles). From the viewpoint of improving surface quality, etc., it is appropriate to set it to 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, even more preferably 2 parts by weight or more, particularly preferably 4 parts by weight or more, and even 6 parts by weight or more. Furthermore, the total content of the water-soluble polymers per 100 parts by weight of abrasive grains may be, for example, 50 parts by weight or less, or may be 30 parts by weight or less. From the viewpoint of the dispersion stability of the polishing composition, etc., in some embodiments, the total content of the water-soluble polymers per 100 parts by weight of abrasive grains is appropriate to set it to 15 parts by weight or less, preferably 12 parts by weight or less, and may be 10 parts by weight or less (for example, less than 10 parts by weight).

[0101] Although not particularly limited, in some embodiments, the ratio (W2 / W1) of the content W2 of the second water-soluble polymer to the content W1 of the first water-soluble polymer is, for example, 0.01 or more by weight, suitably 0.1 or more, preferably 0.2 or more, and may be 0.4 or more, 0.6 or more, or even 0.8 or more. The upper limit of the ratio (W2 / W1) is, for example, 10 or less by weight, suitably 5 or less, preferably 3 or less, more preferably less than 2, and may be 1 or less (less than 1). By appropriately setting the ratio (W2 / W1) within the above range, the effects of the technology disclosed herein can be preferably exhibited.

[0102] The polishing composition disclosed herein may contain, as an optional component, a water-soluble polymer other than the first water-soluble polymer and the second water-soluble polymer (hereinafter also referred to as an optional water-soluble polymer), to the extent that the effects of the present invention are not significantly impaired.

[0103] In an embodiment in which the polishing composition contains an optional water-soluble polymer, the content ratio of the optional water-soluble polymer in the total water-soluble polymers contained in the polishing composition is not particularly limited, but from the viewpoint of effectively exerting the actions of the first water-soluble polymer and the second water-soluble polymer, it is appropriate to make it approximately 50% by weight or less (for example, less than 50% by weight), and it may be 30% by weight or less, less than 10% by weight, less than 3% by weight, or less than 1% by weight. The technology disclosed herein can be preferably implemented in an embodiment in which the polishing composition does not substantially contain any optional water-soluble polymer.

[0104] <Surfactant> In some embodiments, the polishing composition preferably contains at least one surfactant. By incorporating a surfactant into the polishing composition, haze on the polished surface can be reduced. According to the technology disclosed herein, a composition containing the above-described combination of water-soluble polymers and a surfactant can further improve the quality of the polished surface. Any of anionic, cationic, nonionic, and amphoteric surfactants can be used as the surfactant. Typically, anionic or nonionic surfactants are preferred. Nonionic surfactants are more preferred from the viewpoints of low foaming and ease of pH adjustment. Examples of nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives (e.g., polyoxyalkylene adducts) such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; and copolymers of multiple oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers). The surfactants can be used alone or in combination of two or more.

[0105] Specific examples of nonionic surfactants 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, polyoxyethylene octyl ether, polyoxyethylene ... Examples of the hydroxypropyl ether include oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.Among these, preferred surfactants include block copolymers of EO and PO (particularly PEO-PPO-PEO triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ether).The polyoxyethylene alkyl ethers preferably have an EO addition mole number of about 1 to 10 (e.g., about 3 to 8).

[0106] In some embodiments, a nonionic surfactant is preferably used. The use of a nonionic surfactant tends to further improve haze reduction performance.

[0107] The molecular weight of the surfactant is, for example, 1 × 10 4 The molecular weight of the surfactant is preferably less than 200, and from the viewpoint of filterability and washability, it is preferably 9500 or less, and may be, for example, less than 9000. Furthermore, from the viewpoint of surface activity, it is usually appropriate that the molecular weight of the surfactant is 200 or more, and from the viewpoint of haze reduction effect, it is preferably 250 or more (for example, 300 or more). A more preferable range of the molecular weight 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 molecular weight is preferably, for example, less than 2000, more preferably 1900 or less (for example, less than 1800), even more preferably 1500 or less, and may be 1000 or less (for example, 500 or less). Furthermore, when a block copolymer of EO and PO is used as the surfactant, its weight-average molecular weight may be, for example, 500 or more, 1000 or more, even 1500 or more, 2000 or more, or even 2500 or more. The upper limit of the weight-average molecular weight is, for example, 1 × 10 4 It is less than 9,500, preferably less than 9,000, less than 7,000, or less than 5,000, for example.

[0108] The molecular weight of the surfactant may be calculated from the chemical formula, or may be the weight-average molecular weight (water-based, polyethylene glycol equivalent) determined by GPC. For example, in the case of polyoxyethylene alkyl ether, it is preferable to use the molecular weight calculated from the chemical formula, and in the case of a block copolymer of EO and PO, it is preferable to use the weight-average molecular weight determined by GPC.

[0109] Although not particularly limited, in the embodiment in which the polishing composition contains a surfactant, the content of the surfactant is usually 20 parts by weight or less relative to 100 parts by weight of abrasive grains (typically silica particles) from the viewpoint of cleaning properties, etc., preferably 10 parts by weight or less, more preferably 6 parts by weight or less (for example, 3 parts by weight or less).From the viewpoint of better exerting the effect of using the surfactant, the content of the surfactant relative to 100 parts by weight of abrasive grains is 0.001 parts by weight or more, preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, and may be 0.5 parts by weight or more.

[0110] <Water> The water contained in the polishing composition disclosed herein can preferably be ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, or the like. To minimize the inhibition of the functions of other components contained in the polishing composition, the water used preferably contains, for example, 100 ppb or less of transition metal ions in total. For example, the purity of the water can be increased by removing impurity ions using an ion exchange resin, removing foreign matter using a filter, or by distillation. The polishing composition disclosed herein may further contain, as needed, an organic solvent (e.g., a lower alcohol or a lower ketone) that is uniformly miscible with water. Preferably, 90% by volume or more of the solvent contained in the polishing composition is water, and more preferably 95% by volume or more (e.g., 99 to 100% by volume) is water.

[0111] <Other ingredients> The polishing composition disclosed herein may further contain, as needed, known additives that can be used in polishing compositions (e.g., polishing compositions used in the finish polishing step of silicon wafers), such as organic acids, organic acid salts, inorganic acids, inorganic acid salts, chelating agents, preservatives, and fungicides, within the range that does not significantly impair the effects of the present invention.

[0112] Organic acids and their salts, and inorganic acids and their salts can be used alone or in combination. Examples of organic acids include fatty acids such as formic acid, acetic acid, and propionic acid; aromatic carboxylic acids such as benzoic acid and phthalic acid; itaconic acid, citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, fumaric acid, succinic acid, glycolic acid, malonic acid, gluconic acid, alanine, glycine, lactic acid, organic sulfonic acids such as hydroxyethylidene diphosphate (HEDP) and methanesulfonic acid; and organic phosphonic acids such as nitrilotris(methylene phosphoric acid) (NTMP) and phosphonobutanetricarboxylic acid (PBTC). Examples of organic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of organic acids. Examples of inorganic acids include hydrochloric acid, phosphoric acid, sulfuric acid, phosphonic acid, nitric acid, phosphinic acid, boric acid, and carbonic acid. Examples of inorganic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of inorganic acids.

[0113] The chelating agent may be used alone or in combination of two or more. Examples of the chelating agent include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents. Suitable examples of the chelating agent include ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Examples of the preservatives and antifungal agents include isothiazolinone compounds, parahydroxybenzoic acid esters, phenoxyethanol, etc.

[0114] The polishing composition disclosed herein is preferably substantially free of oxidizing agents. If an oxidizing agent is contained in the polishing composition, when the polishing composition is applied to a substrate (e.g., a silicon wafer), the surface of the substrate may be oxidized, forming an oxide film, which may result in a decrease in the polishing rate. Specific examples of oxidizing agents include hydrogen peroxide (HO), sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate. The term "substantially free of oxidizing agents" as used herein means that the polishing composition does not contain an oxidizing agent, at least intentionally. Therefore, a polishing composition that inevitably contains a trace amount of oxidizing agent due to raw materials, manufacturing method, etc. (e.g., a molar concentration of the oxidizing agent in the polishing composition of 0.001 mol / L or less, preferably 0.0005 mol / L or less, more preferably 0.0001 mol / L or less, even more preferably 0.00005 mol / L or less, and particularly preferably 0.00001 mol / L or less) can be included in the concept of a polishing composition that is substantially free of oxidizing agents.

[0115] <ph> The pH of the polishing composition disclosed herein is not particularly limited, and an appropriate pH can be adopted depending on the substrate, etc. In some embodiments, the pH of the polishing composition is suitably 8.0 or higher, preferably 8.5 or higher, and more preferably 9.0 or higher. As the pH of the polishing composition increases, the polishing rate tends to improve. On the other hand, from the viewpoint of preventing dissolution of silica particles and suppressing a decrease in mechanical polishing action, the pH of the polishing composition is usually suitably 12.0 or lower, preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0116] In the technology disclosed herein, the pH of the polishing composition can be determined by using a pH meter (for example, a glass electrode type hydrogen ion concentration indicator (model number F-72) manufactured by Horiba, Ltd.) and performing three-point calibration 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)), then placing the glass electrode in the composition to be measured and measuring the value after stabilization for at least two minutes.

[0117] <Polishing liquid> The polishing composition disclosed herein is typically supplied to the surface of a substrate in the form of a polishing liquid containing the polishing composition, and is used to polish the substrate. The polishing liquid can be prepared, for example, by diluting any of the polishing compositions disclosed herein (typically with water). Alternatively, the polishing composition can be used as a polishing liquid as is. Another example of a polishing liquid containing the polishing composition disclosed herein is a polishing liquid obtained by adjusting the pH of the composition.

[0118] The content of abrasive grains (typically silica particles) in the polishing liquid is not particularly limited, and is, for example, 0.005% by weight or more, preferably 0.01% by weight or more, more preferably 0.03% by weight or more, and even more preferably 0.06% by weight or more. By increasing the abrasive grain content, a higher polishing rate can be achieved. The content is suitably 10% by weight or less, preferably 7% by weight or less, more preferably 5% by weight or less, and even more preferably 2% by weight or less, and may be, for example, 1% by weight or less, 0.5% by weight or less, or 0.4% by weight or less. This makes it easier to maintain surface quality.

[0119] The content of the basic compound in the polishing liquid is not particularly limited. From the viewpoint of improving the polishing rate, the content is usually set to 0.0005% by weight or more, preferably 0.001% by weight or more, and more preferably 0.003% by weight or more. Furthermore, from the viewpoint of improving the surface quality (e.g., reducing haze), the content is set to less than 0.1% by weight, preferably less than 0.05% by weight, and more preferably less than 0.03% by weight (e.g., less than 0.025% by weight, or even less than 0.01% by weight).

[0120] Although not particularly limited, in some embodiments, the content W1 of the first water-soluble polymer (specifically, a polyvinyl alcohol-based polymer) in the polishing liquid may be, for example, 0.0001 wt % or more, typically 0.0005 wt % or more, and preferably 0.001 wt % or more, from the viewpoint of improving surface quality, etc., such as 0.002 wt % or more, or even 0.003 wt % or more. The upper limit of the content W1 of the first water-soluble polymer is not particularly limited, and can be, for example, 0.05 wt % or less. In some embodiments, from the viewpoint of stability at the concentrated liquid stage, polishing rate, cleanability, etc., the content W1 of the first water-soluble polymer is preferably 0.03 wt % or less, more preferably 0.015 wt % or less, and even more preferably 0.01 wt % or less. The polishing liquid disclosed herein may also be implemented in an embodiment in which the content W1 of the first water-soluble polymer is, for example, 0.008 wt % or less, 0.006 wt % or less, or 0.004 wt % or less.

[0121] Although not particularly limited, in some embodiments, the content W2 of the second water-soluble polymer in the polishing liquid may be, for example, 0.0001 wt % or more, typically 0.0005 wt % or more, and preferably 0.001 wt % or more, or 0.002 wt % or more, or 0.003 wt % or more, or even 0.005 wt % or more, from the viewpoint of improving surface quality, etc. The upper limit of the content W2 of the second water-soluble polymer is not particularly limited, and can be, for example, 0.1 wt % or less. In some embodiments, from the viewpoint of stability, polishing rate, cleanability, etc. at the concentrated liquid stage, the content W2 of the second water-soluble polymer is preferably 0.05 wt % or less, more preferably 0.02 wt % or less, and even more preferably 0.01 wt % or less.

[0122] The total content of water-soluble polymers in the polishing liquid is not particularly limited, and in some embodiments, can be, for example, 0.0001% by weight or more. From the viewpoint of reducing haze, etc., the total content is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, even more preferably 0.002% by weight or more, and may be, for example, 0.005% by weight or more. The upper limit of the total content is, for example, 0.5% by weight or less, and from the viewpoint of polishing rate, etc., it is preferably 0.2% by weight or less, more preferably 0.1% by weight or less, and even more preferably 0.05% by weight or less (for example, 0.02% by weight or less, or even 0.015% by weight or less).

[0123] When a surfactant is contained, the content of the surfactant in the polishing liquid (when two or more surfactants are contained, the total content of the surfactants) is not particularly limited as long as it is within a range that does not significantly impair the effects of the present invention. Generally, the content of the surfactant can be, for example, 0.00001% by weight or more from the viewpoint of cleaning properties. From the viewpoint of haze reduction, the content is preferably 0.0001% by weight or more, more preferably 0.0003% by weight or more, and even more preferably 0.0005% by weight or more. Furthermore, from the viewpoint of polishing rate, the content is preferably 0.1% by weight or less, more preferably 0.01% by weight or less, and even more preferably 0.005% by weight or less (for example, 0.002% by weight or less).

[0124] <Concentrate> The polishing composition disclosed herein may be in a concentrated form (i.e., in the form of a concentrated polishing liquid) before being supplied to a substrate. Such a concentrated polishing composition is advantageous from the viewpoints of convenience and cost reduction during production, distribution, storage, etc. The concentration ratio is not particularly limited and can be, for example, about 2 to 100 times in volume terms, and usually about 5 to 50 times (e.g., about 10 to 40 times) is appropriate. Such a concentrated liquid can be diluted at a desired time to prepare a polishing liquid (working slurry), which can then be supplied to a substrate. The dilution can be performed, for example, by adding water to the concentrated liquid and mixing.

[0125] When the polishing composition (i.e., a concentrate) is diluted and used for polishing, the abrasive content in the concentrate can be, for example, 25% by weight or less. From the viewpoints of dispersion stability and filterability of the polishing composition, the content is usually preferably 20% by weight or less, more preferably 15% by weight or less. In some preferred embodiments, the abrasive content may be 10% by weight or less, or may be 5% by weight or less. Furthermore, from the viewpoints of convenience and cost reduction during production, distribution, storage, etc., the abrasive content in the concentrate can be, for example, 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 0.7% by weight or more, and even more preferably 1% by weight or more.

[0126] In some embodiments, the content of the basic compound in the concentrate can be, for example, less than 0.25% by weight. From the viewpoint of storage stability, etc., the content is usually preferably 0.15% by weight or less, more preferably 0.1% by weight or less. Furthermore, from the viewpoint of convenience and cost reduction during production, distribution, storage, etc., the content of the basic compound in the concentrate can be, for example, 0.005% by weight or more, preferably 0.01% by weight or more, more preferably 0.02% by weight or more, and even more preferably 0.05% by weight or more.

[0127] In some embodiments, the total content of the water-soluble polymer in the concentrate can be, for example, 3 wt% or less. From the viewpoint of the filterability and washability of the polishing composition, the content is usually preferably 1 wt% or less, more preferably 0.5 wt% or less. Furthermore, from the viewpoint of convenience and cost reduction during production, distribution, storage, etc., the content is usually 0.001 wt% or more, preferably 0.005 wt% or more, more preferably 0.01 wt% or more.

[0128] In an embodiment in which the polishing composition contains a surfactant, the surfactant content in the concentrate can be, for example, 0.25% by weight or less, preferably 0.15% by weight or less, more preferably 0.1% by weight or less, and may be 0.05% by weight or less, or may be 0.025% by weight or less. The surfactant content in the concentrate can be, for example, 0.0001% by weight or more, preferably 0.001% by weight or more, more preferably 0.005% by weight or more, and even more preferably 0.01% by weight or more.

[0129] <Preparation of Polishing Composition> The polishing composition used in the technology disclosed herein may be a single-component type or a multi-component type such as a two-component type. For example, the polishing composition may be configured so that a polishing liquid is prepared by mixing a part A containing at least abrasive grains among the components of the polishing composition with a part B containing at least a portion of the remaining components, and then mixing and diluting these at an appropriate timing as needed.

[0130] The method for preparing the polishing composition is not particularly limited. For example, the components constituting the polishing composition may be mixed using a well-known mixing device such as a blade mixer, an ultrasonic disperser, or a homomixer. The manner in which these components are mixed is not particularly limited. For example, all the components may be mixed at once, or may be mixed in an appropriately set order.

[0131] <Application> The polishing composition disclosed herein can be used to polish substrates of various materials and shapes. The substrate material can be, for example, a metal or semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, or stainless steel, or an alloy thereof; a glassy material such as quartz glass, aluminosilicate glass, or glassy carbon; a ceramic material such as alumina, silica, sapphire, silicon nitride, tantalum nitride, or titanium carbide; a compound semiconductor substrate material such as silicon carbide, gallium nitride, or gallium arsenide; or a resin material such as polyimide resin. The substrate may be composed of multiple materials selected from these. The shape of the substrate is not particularly limited. The polishing composition disclosed herein can be used to polish flat substrates, such as plate-shaped or polyhedral substrates, or the edge of a substrate (e.g., wafer edge polishing).

[0132] The polishing composition disclosed herein can be particularly preferably used for polishing a surface made of a silicon material (typically, polishing a silicon wafer). Specific examples of silicon materials include silicon single crystal, amorphous silicon, and polysilicon. The polishing composition disclosed herein can be particularly preferably used for polishing a surface made of silicon single crystal (for example, polishing a silicon wafer).

[0133] The polishing composition disclosed herein can be preferably applied to a polishing process of a substrate (e.g., a silicon wafer). Before the polishing process with the polishing composition disclosed herein, the substrate may be subjected to a general treatment that can be applied to a substrate in a process upstream of the polishing process, such as lapping or etching.

[0134] The polishing composition disclosed herein is effective when used in the finishing step of a substrate (e.g., a silicon wafer) or in the polishing step immediately preceding it, and its use in the finishing polishing step is particularly preferred. Here, the finishing polishing step refers to the final polishing step in the manufacturing process of the target object (i.e., a step in which no further polishing is performed after that step). The polishing composition disclosed herein may also be used in a polishing step upstream of the finishing polishing (referring to a preliminary polishing step between the rough polishing step and the final polishing step, which typically includes at least a primary polishing step and may further include secondary, tertiary, etc. polishing steps), for example, a polishing step performed immediately preceding the finishing polishing.

[0135] The polishing composition disclosed herein is effective, for example, for polishing (typically finish polishing or polishing immediately before) silicon wafers that have been prepared to a surface roughness of 0.01 nm to 100 nm in an upstream process. Its application to finish polishing is particularly preferred. The surface roughness Ra of the substrate can be measured, for example, using a laser scanning surface roughness meter "TMS-3000WRC" manufactured by Schmitt Measurement Systems Inc.

[0136] <Polishing> The polishing composition disclosed herein can be used for polishing a substrate, for example, in an embodiment including the following steps: Hereinafter, a preferred embodiment of a method for polishing a silicon wafer as a substrate using the polishing composition disclosed herein will be described. That is, a polishing liquid containing any of the polishing compositions disclosed herein is prepared. The preparation of the polishing liquid may include adjusting the concentration (e.g., diluting) of the polishing composition, adjusting the pH, or the like to prepare the polishing liquid. Alternatively, the polishing composition may be used as is as the polishing liquid.

[0137] Next, the polishing liquid is supplied to the substrate, and polishing is performed by a conventional method. For example, when performing finish polishing of a silicon wafer, typically, a silicon wafer that has undergone a lapping process is set in a general polishing device, and a polishing liquid is supplied to the surface to be polished of the silicon wafer through the polishing pad of the polishing device. Typically, while continuously supplying the polishing liquid, the polishing pad is pressed against the surface to be polished of the silicon wafer, and the two are moved relative to each other (for example, rotated). Polishing of the substrate is completed through this polishing process.

[0138] The polishing pad used in the polishing step is not particularly limited. For example, a polishing pad of a foamed polyurethane type, a nonwoven fabric type, a suede type, or the like can be used. Each polishing pad may contain abrasive grains or may not contain abrasive grains. Usually, a polishing pad that does not contain abrasive grains is preferably used.

[0139] Substrates polished with the polishing composition disclosed herein are typically cleaned. Cleaning can be performed using an appropriate cleaning solution. The cleaning solution used is not particularly limited, and examples include SC-1 cleaning solution (a mixture of ammonium hydroxide (NH4OH), hydrogen peroxide (HO2), and water (HO)) and SC-2 cleaning solution (a mixture of HCl, HO2, and HO), which are commonly used in the semiconductor field. The temperature of the cleaning solution can be, for example, in the range from room temperature (typically about 15°C to 25°C) to about 90°C. From the viewpoint of improving the cleaning effect, a cleaning solution of about 50°C to 85°C can be preferably used.

[0140] As described above, the technology disclosed herein can include a method for manufacturing a polished product (e.g., a method for manufacturing a silicon wafer) that includes a polishing step (preferably finish polishing) by any of the polishing methods described above, and the provision of a polished product (e.g., a silicon wafer) manufactured by the method. [Example]

[0141] Several examples of the present invention will be described below, but it is not intended that the present invention be limited to those shown in these examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0142] <Preparation of Polishing Composition> Example 1 A concentrated solution of the polishing composition according to each example was prepared by mixing abrasive grains, a basic compound, a water-soluble polymer, a surfactant, and deionized water. Colloidal silica with an average primary particle diameter of 25 nm was used as the abrasive grains. Ammonia was used as the basic compound. The water-soluble polymer had a Mw of approximately 1.3 × 10 4 and a water-soluble polymer having a 90:10 molar ratio of vinyl alcohol units to N-vinylpyrrolidone units, and a Mw of approximately 1.4 × 10 4 A random copolymer (PVA-PVP; second water-soluble polymer) having an ethylene oxide addition mole number of 5 was used as the surfactant. Polyoxyethylene decyl ether (C10EO5) having an ethylene oxide addition mole number of 5 was used as the surfactant. The resulting concentrated solution of the polishing composition was diluted 40 times by volume with deionized water to obtain polishing compositions according to the examples with an abrasive concentration of 0.08%, a basic compound concentration of 0.005%, an ac-PVA concentration of 0.003%, a PVA-PVP concentration of 0.001%, and a C10EO5 concentration of 0.0006%.

[0143] Example 2 The second water-soluble polymer has a Mw of approximately 4.9 × 10 4 Poly(N-hydroxyethylacrylamide) (PHEAA) of 0.002% was used. The concentration of PHEAA was 0.002%. The rest of the procedure was the same as in Example 1, and a polishing composition according to this example was prepared.

[0144] Example 3 The first water-soluble polymer was an alkyl-modified PVA (hydrophobically modified PVA) with a Mw of approximately 6000, and the second water-soluble polymer was a 10.5 × 10 4 Polyacryloylmorpholine (PACMO) of 1000 ppm was used. The concentration of PACMO was 0.004%. The polishing composition of this example was prepared in the same manner as in Example 1 except for the above. The alkyl group-modified PVA used in this example is a random copolymer having vinyl alcohol units and n-propyl vinyl ether units in a molar ratio of 85:15.

[0145] Example 4 The second water-soluble polymer has a molecular weight of approximately 136 × 10 4 The polishing composition of this example was prepared in the same manner as in Example 3.

[0146] Example 5 The first water-soluble polymer has a Mw of approximately 7.0 × 10 4 The polishing composition of this example was prepared in the same manner as in Example 4.

[0147] (Comparative Example 1) Poly(vinyl methyl ether) (PVME) was used as the second water-soluble polymer. The concentration of PVME was 0.003%. The polishing composition of this example was prepared in the same manner as in Example 1.

[0148] The etching rates of the first and second water-soluble polymers used in each example were determined based on etching rate measurements. The results are shown in Table 1.

[0149] <Silicon wafer polishing> The substrate was a commercially available silicon single crystal wafer with a diameter of 300 mm (conductivity type: P type, crystal orientation: <100> Silicon wafers (COP (Crystal Originated Particle)-free) were prepared by pre-polishing under the following polishing condition 1. Pre-polishing was performed using a polishing solution containing 0.6% abrasive grains (colloidal silica with an average primary particle diameter of 35 nm) and 0.08% tetramethylammonium hydroxide (TMAH) in deionized water.

[0150] [Polishing conditions 1] Polishing device: Okamoto Machine Tool Works' single-wafer polishing device, model "PNX-332B" Polishing load: 20kPa Rotation speed of the surface plate: 20 rpm Head (carrier) rotation speed: 20 rpm Polishing pad: Fujibo Ehime Co., Ltd., product name "FP55" Polishing fluid supply rate: 1.0 L / min Polishing solution temperature: 20℃ Plate cooling water temperature: 20℃ Polishing time: 2 min

[0151] The polishing compositions according to the examples prepared above were used as polishing liquids to polish the silicon wafers that had been pre-polished as described above under the following polishing conditions 2.

[0152] [Polishing conditions 2] Polishing device: Okamoto Machine Tool Works' single-wafer polishing device, model "PNX-332B" Polishing load: 20kPa Rotation speed of the surface plate: 52 rpm Head (carrier) rotation speed: 50 rpm Polishing pad: Fujibo Ehime Co., Ltd. Product name "POLYPAS275NX" Polishing fluid supply rate: 1.5L / min Polishing solution temperature: 20℃ Plate cooling water temperature: 20℃ Polishing time: 4 min

[0153] The polished silicon wafer was removed from the polishing apparatus and washed using a cleaning solution of NH4OH(29%):H2O2(31%):deionized water(DIW)=2:5.3:48(volume ratio)(SC-1 cleaning). More specifically, a first cleaning tank equipped with an ultrasonic oscillator was prepared, the above cleaning solution was contained in the first cleaning tank and maintained at 70°C, and the polished silicon wafer was immersed in the cleaning tank for 6 minutes. Then, it was immersed in a second cleaning tank containing deionized water(DIW) at 25°C for 15 minutes, then immersed in the first cleaning tank for 6 minutes and the second cleaning tank for 16 minutes again, and then the silicon wafer was dried.

[0154] <LPD-N and haze line measurement> The number of LPD-N and the haze line present on the surface of the cleaned silicon wafer were measured in the DC mode of a wafer inspection apparatus, trade name "Surfscan SP5" manufactured by KLA-Tencor Corporation. The measured number of LPD-N is shown in Table 1. Also, the measured haze line is shown in Table 1 as a value converted to a relative value with the haze line of Comparative Example 1 set to 10000. Note that LPD-N is Light Point Defect Non-cleanable. Also, the haze line refers to the total area of minute scratches present within a predetermined measurement area measured by the above inspection apparatus.

[0155] The outlines and evaluation results of each example are shown in Table 1. In the table, "-" indicates that measurement was impossible.

[0156]

Table 1

[0157] As shown in Table 1, in Examples 1 to 5, which used polishing compositions containing silica particles, a basic compound, and water, which contained a polyvinyl alcohol-based polymer as a first water-soluble polymer and a second water-soluble polymer having a different chemical structure from the first water-soluble polymer, and in which the ratio (ER2 / ER1) of the etching rate ER1 of the first water-soluble polymer to the etching rate ER2 of the second water-soluble polymer was 0.6 or more and 10 or less, both the number of LPD-Ns and haze lines were significantly reduced compared to Comparative Example 1, which used a polishing composition in which the etching rate ratio (ER2 / ER1) was 0.5, thereby achieving high surface quality.

[0158] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above.< / ph>

Claims

1. The composition comprises silica particles (A) as abrasive grains, a basic compound (B), a first water-soluble polymer (C1), a second water-soluble polymer (C2), and water (D), the first water-soluble polymer (C1) is at least one polyvinyl alcohol-based polymer selected from the group consisting of unmodified polyvinyl alcohols having a degree of saponification of 60% or more; acetalized polyvinyl alcohol-based polymers; and polyvinyl alcohol-based polymers containing repeating units derived from alkyl vinyl ether; the second water-soluble polymer (C2) is at least one selected from the group consisting of a polyvinyl alcohol-based polymer having a chemical structure different from that of the first water-soluble polymer (C1); a polymer containing a nitrogen atom; and a polymer containing a (meth)acrylic acid unit; Etch rate measurements for: (1) Prepare an etching rate measurement chemical solution LE containing 0.105 mass % of a water-soluble polymer and ammonia, with the remainder being water, and having a pH of 10.4; (2) NH at 25°C ４ OH (29%): H ２ O ２ A silicon single crystal substrate (rectangular, 6 cm long, 3 cm wide, 775 μm thick) was prepared by immersing it for 1 minute in a cleaning solution of 5% hydrogen fluoride (HF) aqueous solution at 25° C., followed by measuring its mass W0; (3) Immerse the silicon single crystal substrate in the chemical solution LE at 25°C for 48 hours; (4) The silicon single crystal substrate is removed from the chemical solution LE and NH ４ OH (29%): H ２ O ２ Wash with a cleaning solution of (31%):deionized water (DIW) = 1:1:8 (volume ratio) for 10 seconds; (5) measuring the mass W1 of the silicon single crystal substrate after cleaning; and (6) Calculating the etching rate [μm / h] from the difference between W0 and W1 and the specific gravity of the silicon single crystal substrate; The etching rate ER1 of the first water-soluble polymer (C1) and the etching rate ER2 of the second water-soluble polymer (C2) based on the above satisfy the following relationship: A polishing composition satisfying 0.6≦ER2 / ER1≦10.

2. 2. The polishing composition according to claim 1, wherein the first water-soluble polymer (C1) is at least one selected from the group consisting of unmodified polyvinyl alcohol having a degree of saponification of 70% or more; acetalized polyvinyl alcohol-based polymer; and polyvinyl alcohol-based polymer containing a repeating unit derived from an alkyl vinyl ether.

3. 3. The polishing composition according to claim 1, wherein the content of the first water-soluble polymer (C1) is 0.5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the abrasive grains.

4. 4. The polishing composition according to claim 1, wherein the nitrogen atom-containing polymer is a polymer containing a chain amide having an N-(meth)acryloyl group as a monomer unit.

5. 5. The polishing composition according to claim 1, wherein the content of the second water-soluble polymer (C2) is 0.5 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the abrasive grains.

6. The polishing composition according to any one of claims 1 to 5, further comprising a surfactant (E).

7. 7. The polishing composition according to claim 6, wherein the surfactant (E) is a nonionic surfactant.

8. The polishing composition according to any one of claims 1 to 7, which is used for polishing a surface made of a silicon material.

9. A concentrated polishing composition according to any one of claims 1 to 8.

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