Polishing composition

Abstract

Provided is a polishing composition that exhibits good wettability of a surface after polishing and can effectively suppress defects such as haze lines. The polishing composition contains abrasive grains, a basic compound, a cellulose derivative, a modified polyvinyl alcohol-based polymer A, a surfactant, and water. The modified polyvinyl alcohol-based polymer A has a weight average molecular weight Mw of 90,000 or less.

Description

polishing composition

[0001] The present invention relates to an abrasive composition. This application claims priority under Japanese Patent Application No. 2024-167837, filed on 26 September 2024, the entire contents of which are incorporated herein by reference.

[0002] Precision polishing is performed on the surfaces of materials such as metals, metalloids, nonmetals, and their oxides using polishing compositions. For example, the surface of a silicon wafer used as a component of a semiconductor device is generally finished to a high-quality mirror surface through a lapping process (rough polishing process) and a polishing process (precision polishing process). The polishing process typically includes a pre-polishing process (preliminary polishing process) and a finish polishing process (final polishing process). Patent documents 1 to 4 are technical documents relating to polishing compositions mainly used for polishing semiconductor substrates such as silicon wafers.

[0003] Japanese Patent Application Publication No. 2015-76494, Japanese Patent Application Publication No. 2020-13824, Japanese Patent Application Publication No. 2021-102666, International Publication No. 2018 / 096991

[0004] Polishing compositions used for polishing semiconductor substrates such as silicon wafers and other substrates, such as polishing compositions used in the finishing polishing process (particularly the finishing polishing process for semiconductor substrates such as silicon wafers and other substrates), are required to achieve a high-quality surface after polishing. For example, by including a water-soluble polymer in the polishing composition, the substrate is adequately protected, which can improve the surface quality after polishing, such as reducing the haze value. On the other hand, in polishing with a polishing composition containing abrasive grains and a water-soluble polymer, if the protection of the substrate by the water-soluble polymer is insufficient, defects such as minute scratches (haze lines) may be detected in the surface inspection after polishing. The degree of the haze lines is evaluated, for example, by the total area of ​​haze lines present within a predetermined observation area. To improve the surface quality after polishing, it is desirable to reduce the total area.

[0005] Furthermore, to obtain a high-quality surface, it is preferable that the polished surface has sufficient wettability. By keeping the polished surface wet with water (with a film of water attached), it is possible to prevent foreign matter from directly adhering to the polished surface, making it easier to obtain a higher-quality surface after cleaning. To improve the wettability of the polished surface, efforts are being made to include water-soluble polymers that contribute to improved wettability in the polishing composition.

[0006] However, in polishing compositions containing abrasive grains and water-soluble polymers, there was still room for improvement in achieving improved wettability of the surface after polishing and suppression of defects such as haze lines. The present invention was created in view of the above circumstances, and aims to provide a polishing composition that has good wettability of the surface after polishing and can effectively suppress defects such as haze lines.

[0007] The present invention provides an abrasive composition comprising abrasive grains, a basic compound, a cellulose derivative, a modified polyvinyl alcohol polymer A, a surfactant, and water. Here, the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A is 90,000 or less. With an abrasive composition thus comprising abrasive grains and a surfactant, and further comprising a cellulose derivative and a modified polyvinyl alcohol polymer A having a weight-average molecular weight Mw of 90,000 or less, it is possible to effectively suppress defects such as haze lines while maintaining good wettability of the surface after polishing.

[0008] In some embodiments, the polishing composition includes a nonionic surfactant as the surfactant. In embodiments using a nonionic surfactant, it is easier to achieve both improved wettability of the polished surface and suppression of defects such as haze lines.

[0009] In some embodiments, the content W of the modified polyvinyl alcohol polymer A in the polishing composition Ｐ２ Based on [weight %] and the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A, the following formula applies: P = W Ｐ２The value of parameter P calculated by ×Mw is between 2 and 100. When the content and weight-average molecular weight of modified polyvinyl alcohol polymer A are controlled so that the value of parameter P falls within the above range, it is easier to achieve both improved surface wettability after polishing and suppression of defects such as haze lines when used in combination with cellulose derivatives.

[0010] In some embodiments, the weight-based content ratio of the modified polyvinyl alcohol polymer A to the abrasive grains is 0.0001 or more. When the content of the modified polyvinyl alcohol polymer A is within this range in relative ratio to the content of the abrasive grains, it is easier to achieve both improved wettability of the surface after polishing and suppression of defects such as haze lines.

[0011] In some embodiments, the weight-based content ratio of the cellulose derivative to the abrasive grains is greater than 0.06. When the content of the cellulose derivative is within this range in relative ratio to the content of the abrasive grains, it is easier to achieve both improved wettability of the surface after polishing and suppression of defects such as haze lines.

[0012] In some embodiments, the weight-based content ratio of the surfactant to the abrasive grains is 0.10 or less. When the surfactant is included, and its content is within the above range in relative ratio to the abrasive grain content, it is easier to achieve both improved wettability of the surface after polishing and suppression of defects such as haze lines.

[0013] In some embodiments, the weight-based content ratio of the surfactant to the modified polyvinyl alcohol polymer A is less than 1. When the surfactant content is within this range in relative ratio to the content of the modified polyvinyl alcohol polymer A, it is easier to achieve both improved wettability of the surface after polishing and suppression of defects such as haze lines.

[0014] In some embodiments, the polishing composition includes silica particles as the abrasive grains. A polishing composition containing silica particles as abrasive grains makes it easier to obtain a polished surface with excellent surface quality.

[0015] In some embodiments, the abrasive composition may be a concentrate. The abrasive compositions disclosed herein may be manufactured, distributed, and stored as a concentrate.

[0016] This specification provides a polishing method comprising the step of polishing a surface made of a silicon material using the above-mentioned polishing composition. According to the above polishing method, the surface made of the silicon material after polishing may have excellent wettability and suppress surface defects (e.g., haze lines).

[0017] Preferred embodiments of the present invention will be described below. Matters other than those specifically mentioned herein that are necessary for carrying out the present invention can be understood as design matters for those skilled in the art based on the prior art. The present invention can be carried out based on the contents disclosed herein and common technical knowledge in the art.

[0018] <Abrasive Grains> The polishing composition disclosed herein contains abrasive grains. The abrasive grains function to mechanically polish the surface of the object to be polished. The material and properties of the abrasive grains are not particularly limited and can be appropriately selected according to the purpose and manner of use of the polishing composition. Examples of abrasive grains include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include oxide particles such as silica particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and red iron oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; and carbonates such as calcium carbonate and barium carbonate. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles and poly(meth)acrylic acid particles (where (meth)acrylic acid comprehensively refers to acrylic acid and methacrylic acid), and polyacrylonitrile particles. Abrasive grains may be used individually or in combination of two or more types.

[0019] As the abrasive grains, inorganic particles are preferred, and among these, particles made of metal or metalloid oxides are preferred, and silica particles are particularly preferred. For example, in polishing compositions that can be used for polishing objects having a silicon surface, such as silicon wafers (e.g., finish polishing), it is particularly significant to use silica particles as abrasive grains. The technology disclosed herein can preferably be implemented, for example, in a form in which the abrasive grains consist substantially of silica particles. Here, "substantially" means that 95% by weight or more (preferably 98% by weight or more, more preferably 99% by weight or more, and may be 100% by weight) of the particles constituting the abrasive grains are silica particles.

[0020] Specific examples of silica particles include colloidal silica, fumed silica, and precipitated silica. Silica particles can be used individually or in combination of two or more types. Colloidal silica is particularly preferred because it easily yields a polished surface with excellent surface quality after polishing. As colloidal silica, for example, colloidal silica produced from water glass (sodium silicate) by ion exchange or colloidal silica produced by alkoxide method (colloidal silica produced by hydrolysis condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used individually or in combination of two or more types.

[0021] The true specific gravity of the silica constituting the silica particles is preferably 1.5 or higher, more preferably 1.6 or higher, and even more preferably 1.7 or higher. There is no particular upper limit to the true specific gravity of silica, but it is typically 2.3 or lower, for example, 2.2 or lower. The true specific gravity of the silica particles can be measured using a liquid displacement method with ethanol as the displacement solution.

[0022] The average primary particle diameter of the abrasive grains (typically silica particles, preferably colloidal silica) is not particularly limited, but from the viewpoint of polishing rate, it is preferably 5 nm or more, more preferably 10 nm or more. From the viewpoint of obtaining a higher polishing effect (for example, effects such as haze reduction and defect removal), the average primary particle diameter is preferably 15 nm or more, and more preferably 20 nm or more (e.g., greater than 20 nm). Furthermore, from the viewpoint of preventing scratches, the average primary particle diameter of the abrasive grains is preferably 100 nm or less, more preferably 50 nm or less, even more preferably 45 nm or less, and may also be 43 nm or less, less than 40 nm, less than 38 nm, less than 35 nm, less than 32 nm, or less than 30 nm.

[0023] In this specification, the average primary particle diameter of abrasive grains is calculated by taking the specific surface area (BET value) measured by the BET method and determining the average primary particle diameter (nm) = 6000 / (true density (g / cm³) ３ ) × BET value (m ２ This refers to the particle size calculated by the formula ( / g). The specific surface area can be measured, for example, using a surface area measuring device manufactured by Micromeritex, Inc., product name "Flow Sorb II 2300".

[0024] The average secondary particle diameter of the abrasive grains (typically silica particles) is not particularly limited and can be appropriately selected from a range of, for example, 15 nm to 300 nm. From the viewpoint of improving the polishing rate, the average secondary particle diameter is preferably 30 nm or more, and 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, and preferably 44 nm or more. Also, the average secondary particle diameter is usually advantageous to be 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 50 nm or less.

[0025] In this specification, the average secondary particle diameter refers to the particle diameter (volume-average particle diameter) measured by dynamic light scattering. The average secondary particle diameter of abrasive grains can be measured, for example, by dynamic light scattering using the product name "NanoTrack UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0026] The shape (outer form) of the abrasive grains may be spherical or non-spherical. Specific examples of non-spherical particles include peanut-shaped (i.e., the shape of a peanut shell), cocoon-shaped, konpeito-shaped, and rugby ball-shaped particles. For example, abrasive grains in which most of the particles are peanut-shaped or cocoon-shaped may be preferably used.

[0027] While not particularly limited, the average value of the ratio of the major axis to the minor axis of the abrasive grains (average aspect ratio) is, in principle, 1.0 or higher, preferably 1.05 or higher, more preferably 1.1 or higher, and may also be 1.2 or higher. A higher polishing rate can be achieved by increasing the average aspect ratio. Furthermore, from the viewpoint of reducing scratches, the average aspect ratio of the abrasive grains is preferably 3.0 or lower, more preferably 2.0 or lower, even more preferably 1.5 or lower, and may also be 1.4 or lower.

[0028] The shape (outer shape) and average aspect ratio of abrasive grains can be determined, for example, by electron microscopy observation. A specific procedure for determining the average aspect ratio is to use a scanning electron microscope (SEM) to draw the smallest rectangle circumscribing each grain image for a predetermined number of abrasive grains (e.g., 200 grains) whose individual grain shapes can be recognized. Then, for each rectangle drawn for each grain image, the ratio of the major axis to the minor axis is calculated by dividing the length of the major side (major axis value) by the length of the minor side (minor axis value). The average aspect ratio can be obtained by taking the arithmetic mean of the aspect ratios of the predetermined number of grains.

[0029] <Basic Compound> The polishing composition disclosed herein contains a basic compound. In this specification, the basic compound refers to a compound that has the function of dissolving in water and raising the pH of an aqueous solution. As the basic compound, organic or inorganic basic compounds containing nitrogen, hydroxides of alkali metals, hydroxides of alkaline earth metals, quaternary phosphonium compounds, various carbonates and bicarbonates, etc. can be used. Examples of basic compounds containing nitrogen include quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), etc. Such basic compounds can be used alone or in combination of two or more.

[0030] Specific examples of hydroxides of alkali metals include potassium hydroxide, sodium hydroxide, etc. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, sodium carbonate, etc. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, piperazine anhydride, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, azoles such as imidazole and triazole, etc. Specific examples of quaternary phosphonium compounds include quaternary phosphonium hydroxides such as tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, etc.

[0031] As the quaternary ammonium compound, quaternary ammonium salts (typically strong bases) such as tetraalkylammonium salts, hydroxyalkyltrialkylammonium salts, etc. can be preferably used. The anion component in such quaternary ammonium salts is, for example, OH － , F － , Cl － , Br － , I － , ClO ４ － , BH ４－ These are some possibilities. A particularly favorable example is an anion with OH － Examples include quaternary ammonium salts, i.e., quaternary ammonium hydroxides. Specific examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide; and hydroxyalkyltrialkylammonium hydroxides such as 2-hydroxyethyltrimethylammonium hydroxide (also known as choline); and so on.

[0032] Of these basic compounds, at least one basic compound selected from alkali metal hydroxides, quaternary ammonium hydroxides, and ammonia can be preferably used. Potassium hydroxide, tetraalkylammonium hydroxide (e.g., tetramethylammonium hydroxide), and ammonia are more preferred, with ammonia being particularly preferred.

[0033] <Cellulose Derivatives> The polishing compositions disclosed herein include a cellulose derivative as a first water-soluble polymer (hereinafter also referred to as "water-soluble polymer P1"). Although not interpreted as particularly restrictive, the cellulose derivative acts on both the abrasive grains and the substrate (e.g., a silicon wafer) and moderately protects the substrate surface. By using the cellulose derivative in combination with a modified polyvinyl alcohol-based polymer described later, protection of the substrate surface and improvement of the wettability of the surface after polishing tend to be suitably achieved.

[0034] Cellulose derivatives are polymers that contain β-glucose units as their main repeating units. Specific examples of cellulose derivatives include hydroxyethylcellulose (HEC), hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, and carboxymethylcellulose. Among these, HEC is preferred.

[0035] The weight-average molecular weight (Mw) of the cellulose derivative used in the polishing compositions disclosed herein is not particularly limited. The weight-average molecular weight (Mw) of the cellulose derivative is approximately 200 × 10 ４ It can be as follows: 150 x 10 ４ The following is appropriate. The above Mw is approximately 100 x 10 ４ The following are also acceptable, approximately 50 x 10 ４ The following (for example, approximately 50 x 10 ４ Less than 40 x 10 ４ The following is also acceptable, approximately 30 x 10 ４ (for example, 30 x 10) ４ It may also be less than ). Using a cellulose derivative with a moderately limited Mw tends to result in better surface quality. Also, from the viewpoint of protecting the polished surface, the above Mw is, for example, approximately 2 × 10 ３ That is all, approximately 5 x 10 ３ It is appropriate for the above to be true, preferably about 1 × 10 ４ More preferably, approximately 3 x 10 ４ More preferably, approximately 10 x 10 ４ That is all, approximately 20 x 10 ４ That's fine too.

[0036] In this specification, the weight-average molecular weight (Mw) of surfactants such as cellulose derivatives, modified polyvinyl alcohol polymers, other water-soluble polymers, and block copolymers of EO and PO may be calculated using values ​​based on aqueous gel permeation chromatography (GPC) (aqueous, polyethylene oxide equivalent). A Tosoh Corporation model "HLC-8320GPC" is recommended as the GPC measuring device. The measurement conditions are as follows. The same method is used for the examples described later. [GPC Measurement Conditions] Sample concentration: 0.1% by weight Column: TSKgel GMPW ＸＬ Detector: Differential refractometer Eluent: 100 mM sodium nitrate aqueous solution / acetonitrile = 10-8 / 0-2 Flow rate: 0.5 mL / min Measurement temperature: 40°C Sample injection volume: 100 μL

[0037] Abrasive grain (typically silica particles) content W Ａ Content of cellulose derivative relative to W Ｐ１ The ratio is not particularly limited. In some preferred embodiments, the content of abrasive particles (typically silica particles) W Ａ Content of cellulose derivative relative to W Ｐ１ The ratio of the weight basis (W Ｐ１ / W Ａ ) is greater than 0.06. In relation to the abrasive content, when the cellulose derivative content is within the above range, protection of the substrate surface and improvement of the wettability of the surface after polishing tend to be more favorably exhibited. In some embodiments, the above ratio (W Ｐ１ / W Ａ The ratio (W) is 0.061 or greater. Ｐ１ / W Ａ The upper limit of ) is not particularly limited, but for example it may be 100 or less, 10 or less, 5 or less, or 1 or less. From the viewpoint of polishing rate, the above ratio (W Ｐ１ / W Ａ For example, the value is preferably 0.50 or less, may be 0.10 or less, 0.098 or less, 0.096 or less, 0.09 or less, 0.08 or less, 0.07 or less, or 0.065 or less.

[0038] <Modified Polyvinyl Alcohol Polymer> The polishing composition disclosed herein includes a modified polyvinyl alcohol polymer as a second water-soluble polymer (hereinafter also referred to as "water-soluble polymer P2"). By using a cellulose derivative as water-soluble polymer P1 in combination with a modified polyvinyl alcohol polymer as water-soluble polymer P2, it tends to be possible to suitably suppress defects such as haze lines, which were limited when using only a cellulose derivative. Furthermore, since the modified polyvinyl alcohol polymer exhibits appropriate hydrophilicity, it also contributes to improving the wettability of the surface after polishing. Therefore, by using a cellulose derivative as water-soluble compound P1 and a modified polyvinyl alcohol polymer as water-soluble polymer P2 in combination, it is easy to realize a polishing composition that has good wettability of the surface after polishing and can effectively suppress defects such as haze lines.

[0039] Herein, in this specification, a modified polyvinyl alcohol-based polymer is defined as having the repeating unit -CH ２ This includes vinyl alcohol units represented by -CH(OH)- (hereinafter also referred to as "VA units") and repeating units other than VA units (hereinafter also referred to as "non-VA units").

[0040] [Acetalized Polyvinyl Alcohol] In some preferred embodiments, acetalized polyvinyl alcohol is used as the modified polyvinyl alcohol polymer. The acetalized polyvinyl alcohol can include structural units represented by the following formula (I) (hereinafter also referred to as "VAC units") and structural units represented by the following formula (II) (i.e., VA units). When a polishing composition containing the above-mentioned acetalized polyvinyl alcohol in addition to abrasive grains, a basic compound, a cellulose derivative, and water is used, it is easy to achieve a high-quality surface with good wettability of the surface after polishing while suppressing defects such as haze lines.

[0041] (R １ (This is a hydrocarbon group.)

[0042] Acetalized polyvinyl alcohol can be obtained by reacting some of the hydroxyl groups of a polyvinyl alcohol polymer with an aldehyde compound or a ketone compound to acetalize it. The acetalized polyvinyl alcohol disclosed herein is typically obtained by an acetalization reaction between a polyvinyl alcohol polymer and an aldehyde compound or a ketone compound. The aldehyde compound or ketone compound is R in formula (I) above. １ A hydrocarbon group is used. In some preferred embodiments, the acetalized polyvinyl alcohol may be a water-soluble polymer obtained by an acetalization reaction between a polyvinyl alcohol-based polymer and an aldehyde compound having 1 to 7 carbon atoms.

[0043] In the technology disclosed herein, the degree of saponification of the polyvinyl alcohol-based polymer may be, for example, 60% or more, and from the viewpoint of water solubility, it may be 70% or more, 80% or more, 90% or more, 95% or more, 97% or more, or 98% or more. In principle, the degree of saponification of the polyvinyl alcohol-based polymer is 100% or less.

[0044] In the technology disclosed herein, the polyvinyl alcohol polymer (PVA) used to produce acetalized polyvinyl alcohol may be unmodified PVA or modified PVA. The unmodified PVA is produced by hydrolysis (saponification) of polyvinyl acetate, and the vinyl polymerized vinyl acetate unit (-CH ２ -CH (OCOCH) ３ This refers to a polyvinyl alcohol-based polymer that substantially contains no structural units other than VA units. In some preferred embodiments, only one or more unmodified PVAs are used as the polyvinyl alcohol-based polymer used to produce acetalized polyvinyl alcohol.

[0045] In the techniques disclosed herein, the aldehyde compound used to obtain acetalized polyvinyl alcohol is a compound consisting of carbon atoms and hydrogen atoms, excluding the oxygen atom contained in the aldehyde group. Specific examples of the above aldehyde compounds include formaldehyde; alkylaldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, t-butyraldehyde, n-pentylaldehyde, and hexylaldehyde (including linear alkylaldehydes and branched alkylaldehydes); alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde; and the like. The above aldehyde compounds may be used individually or in combination of two or more.

[0046] In some embodiments, the aldehyde compound is preferably one or more selected from the group consisting of formaldehyde and alkylaldehydes having 2 to 7 carbon atoms, due to its high solubility in water and ease of acetalization. The acetalization reaction between the polyvinyl alcohol polymer and the aldehyde compound produces a unit represented by the following formula (IA) (hereinafter also referred to as "unit (IA)").

[0047] (R ２ (This is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

[0048] In the above formula (IA), R ２ R is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. ２ This can be any one of these, or a combination of two or more.

[0049] The degree of acetalization of the acetalized polyvinyl alcohol disclosed herein is not particularly limited. From the viewpoint of suppressing defects such as haze lines when used with cellulose derivatives, the degree of acetalization of the acetalized polyvinyl alcohol is, for example, 3% or more, preferably 5% or more, and may be 10% or more, 15% or more, or 20% or more. From the viewpoint of improving wettability, the degree of acetalization of the acetalized polyvinyl alcohol is, for example, 50% or less, preferably 40% or less, and may be 35% or less, 30% or less, or 25% or less.

[0050] In this specification, the degree of acetalization of the acetalized polyvinyl alcohol is defined as the number of units (II) N contained in the polyvinyl alcohol before acetalization. ０ And the number of units (II) contained in the above acetalized polyvinyl alcohol, N １ Using the following formula, the degree of acetalization [%] = (N ０ -N １ ) / N ０It is expressed as ×100;. Therefore, the degree of acetalization of the above acetalized polyvinyl alcohol means the extent to which the OH groups of unit (II) contained in the polyvinyl alcohol before acetalization are acetalized in the above acetalized polyvinyl alcohol.

[0051] In some embodiments, a copolymer containing vinyl alcohol units (VA units) and repeating units other than VA units (hereinafter also referred to as "non-VA units") in a single molecule can be preferably used as the modified polyvinyl alcohol polymer. The modified polyvinyl alcohol polymer may be a random copolymer containing VA units and non-VA units, or it may be a block copolymer or a graft copolymer. The modified polyvinyl alcohol polymer may contain only one type of non-VA unit, or it may contain two or more types of non-VA units.

[0052] For example, a modified polyvinyl alcohol polymer may contain VA units and non-VA units having at least one structure selected from oxyalkylene groups, carboxyl 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. Furthermore, the non-VA units that may be included in the modified polyvinyl alcohol polymer may be, but are not limited to, repeating units derived from N-vinyl type monomers or N-(meth)acryloyl type monomers described later, 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, repeating units derived from (di)acetone compounds, etc. One preferred example of the above N-vinyl type monomer is N-vinylpyrrolidone. One preferred example of the above N-(meth)acryloyl type monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be a vinyl ether having an alkyl group with 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate. Examples of the (di)acetone compound include diacetone (meth)acrylamide and acetylacetone.

[0053] In some embodiments, a cation-modified polyvinyl alcohol in which a cationic group such as a quaternary ammonium structure has been introduced may be used as the modified polyvinyl alcohol polymer. Examples of the cation-modified polyvinyl alcohol include those in which a cationic group derived from a monomer having a cationic group, such as diallyldialkylammonium salt or N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt has been introduced.

[0054] Furthermore, as a modified polyvinyl alcohol-based polymer, the non-VA unit has the chemical formula: -CH２ -CH(CR ３ (OR ６ )-CR ４ (OR ７ )-R ５ ) - A structural part represented by - may be used. Here R ３ ~R ５ Each of these independently represents a hydrogen atom or an organic group, R ６ and R ７ Each is independently a hydrogen atom or R ８ -CO- (wherein, R ８ R represents an alkyl group. For example, R in the above chemical formula ３ ~R ５ If at least one of the elements is an organic group, the organic group may be a linear or branched alkyl group having 1 to 8 carbon atoms. Also, R in the above chemical formula ６ This can be a linear or branched alkyl group having 1 to 8 carbon atoms.

[0055] In some embodiments, a modified polyvinyl alcohol polymer having a 1,2-diol structure in its side chain is used. For example, as the above modified polyvinyl alcohol polymer, the above R ３ ~R ７ Modified PVA (butenediol vinyl alcohol copolymer (BVOH)) containing non-VA units in which hydrogen atoms can preferably be used.

[0056] In this specification, "(meth)acryloyl" comprehensively refers to acryloyl and methacryloyl types. Similarly, in this specification, "(meth)acrylic" comprehensively refers to acrylic and methacrylic.

[0057] The ratio of moles of VA units to the total number of moles of repeating units constituting the modified polyvinyl alcohol 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 ratio of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (for example, 95% or more, or 98% or more). In some other embodiments, the ratio of moles of VA units to the total number of moles of repeating units constituting the modified polyvinyl alcohol polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0058] The VA unit content (weight-based content) in the modified polyvinyl alcohol polymer 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. In some embodiments, the VA unit content may be 50% by weight or more (for example, more than 50% by weight), 70% by weight or more, or 80% by weight or more (for example, 90% by weight or more, or 95% by weight or more, or 98% by weight or more). In some other embodiments, the VA unit content in the modified polyvinyl alcohol 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.

[0059] A modified polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit content within the same molecule. Here, a polymer chain refers to a part (segment) that constitutes a portion of a polymer molecule. For example, a polyvinyl alcohol-based polymer may contain polymer chain A, which has a VA unit content of more than 50% by weight, and polymer chain B, which has a VA unit content of less than 50% by weight (i.e., a non-VA unit content of more than 50% by weight), within the same molecule.

[0060] Polymer chain A may contain only VA units as repeating units, or it may contain non-VA units in addition to VA units. The VA unit content in polymer chain 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 VA unit content in 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 polymer chain A may be VA units.

[0061] Polymer chain B may contain only non-VA units as repeating units, or it may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain 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.

[0062] Examples of modified polyvinyl alcohol polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The above graft copolymer may be a graft copolymer in which polymer chain B (side chain) is grafted onto polymer chain A (main chain), or a graft copolymer in which polymer chain A (side chain) is grafted onto polymer chain B (main chain). In one embodiment, a polyvinyl alcohol polymer in which polymer chain B is grafted onto polymer chain A can be used.

[0063] Examples of polymer chain B include polymer chains whose main repeating unit is a repeating unit derived from an N-vinyl type monomer; polymer chains whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer; polymer chains whose main repeating unit is a repeating unit derived from vinyl dicarboxylates such as fumaric acid, maleic acid, and maleic anhydride; polymer chains whose main repeating unit is a repeating unit derived from aromatic vinyl monomers such as styrene and vinylnaphthalene; and polymer chains whose main repeating unit is an oxyalkylene unit. In this specification, unless otherwise specified, a main repeating unit refers to a repeating unit that is present in an amount exceeding 50% by weight.

[0064] One preferred example of polymer chain B is a polymer chain whose main repeating unit is an N-vinyl type monomer, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl type monomers in the N-vinyl polymer chain is typically more than 50% by weight, may be 70% or more by weight, 85% or more by weight, or 95% or more by weight. Substantially all of polymer chain B may consist of repeating units derived from N-vinyl type monomers.

[0065] Examples of N-vinyl monomers include monomers having a nitrogen-containing heterocyclic ring (e.g., a lactam ring) and N-vinyl chain amides. Specific examples of N-vinyl lactam monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholindione. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. Polymer chain B may be an N-vinyl polymer chain in which more than 50% by weight (e.g., 70% or more by weight, or 85% or more by weight, or 95% or more by weight) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinylpyrrolidone units.

[0066] Another example of polymer chain B is a polymer chain whose main repeating unit is an N-(meth)acryloyl type monomer, i.e., an N-(meth)acryloyl polymer chain. The content of repeating units derived from N-(meth)acryloyl type monomers in an N-(meth)acryloyl polymer chain is typically more than 50% by weight, may be 70% or more by weight, 85% or more by weight, or 95% or more by weight. Substantially all of polymer chain B may consist of repeating units derived from N-(meth)acryloyl type monomers.

[0067] Examples of N-(meth)acryloyl type monomers include chain amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamides; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-n-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.

[0068] Another example of polymer chain B is a polymer chain containing oxyalkylene units as the main repeating units, i.e., an oxyalkylene polymer chain. The content of oxyalkylene units in an oxyalkylene polymer chain is typically more than 50% by weight, may be 70% or more by weight, 85% or more by weight, or 95% or more by weight. Substantially all of the repeating units contained in polymer chain B may be oxyalkylene units.

[0069] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be repeating units derived from the corresponding alkylene oxide. The oxyalkylene polymer chain may contain one type of oxyalkylene unit or two or more types. For example, it may be an oxyalkylene polymer chain containing a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, these oxyalkylene units may be random copolymers of the corresponding alkylene oxides, block copolymers, or graft copolymers.

[0070] Further examples of polymer chain B include polymer chains containing repeating units derived from alkyl vinyl ethers (e.g., vinyl ethers having alkyl groups with 1 to 10 carbon atoms), polymer chains containing repeating units derived from monocarboxylate vinyl esters (e.g., vinyl esters of monocarboxylic acids having 3 or more carbon atoms), and polymer chains into which cationic groups (e.g., cationic groups having a quaternary ammonium structure) are introduced.

[0071] The polishing composition disclosed herein has a weight-average molecular weight (Mw) of 9 × 10 ４ It is characterized by containing a modified polyvinyl alcohol-based polymer (hereinafter also referred to as "modified polyvinyl alcohol-based polymer A") whose Mw is 9 × 10 ４ According to the modified polyvinyl alcohol polymer A described below, when used in combination with a cellulose derivative, it maintains good wettability of the surface after polishing, improves the homogeneity of surface protection, and makes it easier to suppress defects such as haze lines. From the viewpoint of further suppressing defects such as haze lines, the Mw of the modified polyvinyl alcohol polymer A is preferably 7 × 10 ４ The following, more preferably 6 × 10 ４ The following is true: 5.5 × 10 ４ The following may also be true: 5 x 10 ４ The following is also acceptable: 4 x 10 ４It may also be 3.5×10 ４ It may also be 3×10 ４ It may also be 2.5×10 ４ It may also be 2×10 ４ It may be below (for example, below 2×10 ４ and less), 1.5×10 ４ It may also be 1.2×10 ４ It may also be 1×10 ４ or less.

[0072] Since it is easy to exhibit appropriate adsorptivity to the surface to be polished, the Mw of the modified polyvinyl alcohol-based polymer A is, for example, 1×10 ３ or more, 2×10 ３ or more, 3×10 ３ or more, 4×10 ３ or more, 5×10 ３ or more or 6×10 ３ or more, and may be 7×10 ３ or more, and may also be 8×10 ３ or more.

[0073] The more preferable range of the weight average molecular weight of the modified polyvinyl alcohol-based polymer A varies depending on the type of the modified polyvinyl alcohol-based polymer. For example, when using acetalized polyvinyl alcohol as the modified polyvinyl alcohol-based polymer A, its weight average molecular weight (Mw) is 9×10 ４ or less, and may be 7×10 ４ or less, and may be 6×10 ４ or less, and may be 5×10 ４ or less. That the Mw of acetalized polyvinyl alcohol is not too large can be advantageous from the viewpoint of enhancing the homogeneity of surface protection and suppressing defects such as haze lines. From such a viewpoint, in some embodiments, the Mw of acetalized polyvinyl alcohol is preferably 3.5×10 ４ or less, more preferably 3×10 ４ or less, and may be 2.5×10 ４ or less, and may be 2×10 ４ or less (for example, less than 2×10 ４ ), and may be 1.5×10 ４The following is also acceptable: 1.2 × 10 ４ The following is also acceptable: 1 x 10 ４ The following is also acceptable. Furthermore, the Mw of acetalized polyvinyl alcohol is, for example, 1 × 10⁻⁶. ３ The above is 2 x 10 ３ The above is 3 x 10 ３ The above is 4 x 10 ３ The above 5 x 10 ３ or more, or 6 x 10 ３ The above is sufficient, and since it easily exhibits appropriate adsorption to the surface to be polished, in some embodiments it is 7 × 10 ３ Preferably, it should be 8 x 10 ３ It is more preferable that the above conditions are met.

[0074] For example, when a copolymer of PEO and PVA is used as the modified polyvinyl alcohol polymer A, its weight-average molecular weight (Mw) is 9 × 10⁻⁶. ４ The following is true: 6 × 10 ４ The following may also be true: 5 x 10 ４ The following is also possible. Having a Mw of the PEO-PVA copolymer that is not too large can be advantageous in terms of improving the homogeneity of surface protection and suppressing defects such as haze lines. From this viewpoint, in some embodiments, the Mw of the PEO-PVA copolymer is 3.5 × 10 ４ The following is preferable: 3 × 10 ４ It is more preferable that the following conditions apply: 2.5 × 10 ４ The following is also acceptable: 2 x 10 ４ (for example, 2 x 10) ４ It may be less than ). Also, the Mw of the PEO-PVA copolymer is, for example, 1 × 10⁻⁶. ３ The above is 2 x 10 ３ The above is 3 x 10 ３ The above is 4 x 10 ３ The above is sufficient, and since it easily exhibits appropriate adsorption to the surface to be polished, in some embodiments it is 8 × 10 ３ Preferably, it is 10 x 10 ３ That's fine too.

[0075] For example, when a copolymer of PVP and PVA is used as the modified polyvinyl alcohol polymer A, its weight-average molecular weight (Mw) is 9 × 10⁻⁶. ４ The following is true: 6 × 10 ４ The following may also be true: 5 x 10 ４ The following is also possible. Having a Mw of the PVP-PVA copolymer that is not too large can be advantageous in terms of improving the homogeneity of surface protection and suppressing defects such as haze lines. From this viewpoint, in some embodiments, the Mw of the PVP-PVA copolymer is 4 × 10 ４ The following is preferable: 3 × 10 ４ The following may also be true: 2.5 × 10 ４ The following is also acceptable: 2 x 10 ４ (for example, 2 x 10) ４ It may be less than ). Also, the Mw of the PVP and PVA copolymer is, for example, 1 × 10⁻⁶. ３ The above is 2 x 10 ３ The above is 3 x 10 ３ The above is 4 x 10 ３ The above is sufficient, and since it easily exhibits appropriate adsorption to the surface to be polished, in some embodiments it is 8 × 10 ３ Preferably, it is 1 x 10 ４ That's fine too.

[0076] For example, if a modified polyvinyl alcohol polymer A is used in which some of the hydroxyl groups in the PVA main chain are replaced with hydrocarbon-containing groups such as alkyl groups, alkyl ether groups, or aromatic groups, and is not acetalized PVA (hereinafter also referred to as "hydrocarbon-modified PVA"), its weight-average molecular weight (Mw) is 9 × 10⁻⁶. ４ The following is true: 6 × 10 ４ The following may also be true: 5 x 10 ４ The following is also acceptable. Having a Mw of the hydrocarbon-modified PVA not too large can be advantageous from the viewpoint of improving the homogeneity of surface protection and suppressing defects such as haze lines. From this viewpoint, in some embodiments, the Mw of the hydrocarbon-modified PVA is 4 × 10 ４ Preferably, it is 3.5 × 10 ４ The following is also acceptable: 3 x 10 ４The following is also acceptable. Furthermore, the Mw of the above hydrocarbon group-modified PVA is, for example, 1 × 10⁻⁶. ３ The above is 2 x 10 ３ The above is 3 x 10 ３ The above is 4 x 10 ３ The above is sufficient, and since it easily exhibits appropriate adsorption to the surface to be polished, in some embodiments it is 8 × 10 ３ Preferably, it is 1 x 10 ４ It may be greater than or equal to 1.5 × 10 ４ The above is also acceptable: 2 x 10 ４ The above is also acceptable, 2.5 x 10 ４ That's fine too.

[0077] In some embodiments, the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A and its content may correlate with the manifestation of the effects of the invention. Therefore, by setting the parameters defined by combining the two within a certain range, it is possible to maintain good wettability of the surface after polishing when used in combination with a cellulose derivative, while improving the homogeneity of surface protection and effectively suppressing defects such as haze lines. From this viewpoint, in some embodiments, the content W of the modified polyvinyl alcohol polymer A in the polishing composition Ｐ２ Based on [weight %] and the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A, the following formula applies: P = W Ｐ２ The value of parameter P calculated by ×Mw is preferably 1 or greater, more preferably 2 or greater, even more preferably 3 or greater, and most preferably 6 or greater. A larger value of parameter P tends to increase the protective effect of the modified polyvinyl alcohol polymer A on the surface to be polished. In some embodiments, the value of parameter P may be 7 or greater, or 10 or greater.

[0078] On the other hand, from the viewpoint of improving the homogeneity of surface protection and suppressing defects such as haze lines, it is appropriate for the parameter P to be 130 or less, preferably 100 or less, more preferably 80 or less, and even more preferably 60 or less. Furthermore, in some embodiments, the parameter P may be 50 or less, 45 or less, 30 or less, or 20 or less.

[0079] If the polishing composition disclosed herein contains two or more modified polyvinyl alcohol polymers A, the parameter P can be defined by calculating the value obtained by multiplying the content (by weight) of each modified polyvinyl alcohol polymer A by its weight-average molecular weight Mw, and then summing these values ​​for all modified polyvinyl alcohol polymers A. That is, the parameter P is given by the following equation: P = Σ(W Ｐ２ｉ ×Mw ｉ ); is calculated by ); where W Ｐ２ｉ The value indicates the content [weight %] of modified polyvinyl alcohol polymer i in the abrasive composition, and Mw ｉ This indicates the weight-average molecular weight of the modified polyvinyl alcohol-based polymer.

[0080] While not particularly limited, the amount of abrasive particles (typically silica particles) W Ａ Content W of modified polyvinyl alcohol polymer A Ｐ２ The ratio of the weight basis (W Ｐ２ / W Ａ ) can be, for example, 0.0001 or more, and is usually appropriate to be 0.0005 or more. From the viewpoint of better suppressing defects such as haze lines, in some embodiments, the ratio (W Ｐ２ / W Ａ The ratio (W) is preferably 0.001 or higher, may be 0.002 or higher, or 0.0028 or higher. Ｐ２ / W Ａ ) may be, for example, 100 or less, 10 or less, 5 or less, or 1 or less. From the viewpoint of polishing rate, the above ratio (W Ｐ２ / W Ａ) is preferably 0.5 or less, may be 0.3 or less, or 0.2 or less. From the viewpoint of making it easier to obtain a higher processing force, in some embodiments the above ratio (W Ｐ２ / W Ａ It is appropriate to set the ratio to 0.15 or less, preferably to 0.1 or less, and it may also be 0.07 or less, 0.05 or less, 0.04 or less, 0.03 or less, or 0.02 or less.

[0081] While not particularly limited, the content of cellulose derivatives W Ｐ１ Content W of modified polyvinyl alcohol polymer A Ｐ２ The ratio of the weight basis (W Ｐ２ / W Ｐ１ The ratio (W) can be, for example, 0.001 or higher, and is usually appropriate to be 0.005 or higher. From the viewpoint of better suppressing defects such as haze lines, in some embodiments, the ratio (W) can be set to 0.001 or higher. Ｐ２ / W Ｐ１ The ratio (W) is preferably 0.008 or higher, but may be 0.01 or higher, or 0.05 or higher. Furthermore, from the viewpoint of achieving a good balance between suppressing defects such as haze lines and improving the wettability of the surface after polishing, the above ratio (W) is used. Ｐ２ / W Ｐ１ ) may be, for example, 100 or less, 50 or less, or 10 or less. In some embodiments, the above ratio (W Ｐ２ / W Ｐ１ It is appropriate for the value to be 5 or less, preferably 1 or less, and may also be 0.5 or less, 0.3 or less, 0.2 or less, 0.1 or less, or 0.06 or less.

[0082] As long as it does not significantly impair the effects of the invention disclosed herein, the polishing composition has a weight-average molecular weight Mw of approximately 9 × 10 ４ It may also contain a larger modified polyvinyl alcohol polymer. From the viewpoint of ensuring the effect of using modified polyvinyl alcohol polymer A, in some embodiments, the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer contained in the polishing composition is 9 × 10 ４The proportion of the larger modified polyvinyl alcohol polymer is preferably 25% or less by weight, but may be 15% or less, 10% or less, 5% or less, or 3% or less. In some preferred embodiments, the polishing composition disclosed herein has a weight-average molecular weight Mw of 9 × 10 ４ It is substantially free of larger modified polyvinyl alcohol polymers. Here, "substantially free" means that the abrasive composition is at least intentionally free of a weight-average molecular weight Mw of 9 × 10⁶. ４ This means that the composition does not contain larger modified polyvinyl alcohol polymers; for example, the weight-average molecular weight Mw in the polishing composition is 9 × 10 ４ A higher content of modified polyvinyl alcohol-based polymer is 1 × 10 －６ It is less than or equal to a percentage by weight, and more preferably 1 × 10 －７ It is less than or equal to a percentage by weight, and can even be 0% by weight.

[0083] <Optional Water-Soluble Polymers> In addition to the cellulose derivatives and modified polyvinyl alcohol polymers described above, the polishing compositions disclosed herein may also contain, as an optional component, a water-soluble polymer P3 selected from polymers other than those described above. The water-soluble polymer P3 can help improve the protective properties and wettability of the surface to be polished. Nonionic, anionic, or cationic polymers can be used as the water-soluble polymer P3. For example, a polymer having at least one of the following in its molecule—such as a hydroxyl group, carboxyl group, acyloxy group, sulfo group, primary amide structure, heterocyclic structure, vinyl structure, or polyoxyalkylene structure—can be used as the water-soluble polymer P3. The water-soluble polymer P3 can be used alone or in combination of two or more. From the viewpoint of reducing aggregates and improving cleaning performance, nonionic polymers can be preferably used as the water-soluble polymer P3 in some embodiments.

[0084] Examples of water-soluble polymers P3 include starch derivatives, polymers containing oxyalkylene units, unmodified polyvinyl alcohol (unmodified PVA), polymers containing nitrogen atoms, and carboxylic acid polymers.

[0085] Starch derivatives are polymers that contain α-glucose units as their main repeating units. Specific examples of starch derivatives include pregelatinized starch, pullulan, carboxymethyl starch, and cyclodextrin. Among these, pullulan is preferred.

[0086] Examples of polymers containing oxyalkylene units 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. Block copolymers of EO and PO may include diblock copolymers and triblock copolymers containing PEO blocks and polypropylene oxide (PPO) blocks. Examples of the above triblock copolymers include PEO-PPO-PEO type triblock copolymers and PPO-PEO-PPO type triblock copolymers. Generally, PEO-PPO-PEO type triblock copolymers are more preferred.

[0087] In this specification, unless otherwise specified, the term "polymer" comprehensively refers to various types of copolymers, including random copolymers, alternating copolymers, block copolymers, and graft copolymers.

[0088] In a block copolymer or random copolymer of EO and PO, the molar ratio of EO to PO constituting the copolymer (EO / PO) is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more (for example, 5 or more) from the viewpoint of solubility in water and washability.

[0089] The degree of saponification of unmodified polyvinyl alcohol (unmodified PVA) may be, for example, 60% or more, and from the viewpoint of water solubility, it may be 70% or more, 80% or more, 90% or more, 95% or more, 97% or more, or 98% or more.

[0090] Non-limiting examples of polymers containing nitrogen atoms include polymers containing N-vinyl type monomer units; imine derivatives; polymers containing N-(meth)acryloyl type monomer units; and the like.

[0091] Examples of polymers containing N-vinyl monomer units include polymers containing repeating units derived from monomers having nitrogen-containing heterocyclic rings (e.g., lactam rings). Examples of such polymers include homopolymers and copolymers of N-vinyllactam monomers (e.g., copolymers in which the copolymerization ratio of N-vinyllactam monomers exceeds 50% by weight), and homopolymers and copolymers of N-vinyl chain amides (e.g., copolymers in which the copolymerization ratio of N-vinyl chain amides exceeds 50% by weight).

[0092] Specific examples of N-vinyllactam 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, and N-vinyl-3,5-morpholindione. Specific examples of polymers containing N-vinyllactam monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), and block 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.

[0093] Examples of polymers containing N-(meth)acryloyl type monomer units include homopolymers and copolymers of N-(meth)acryloyl type monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl type monomers exceeds 50% by weight). Examples of N-(meth)acryloyl type monomers include chain amides having N-(meth)acryloyl groups and cyclic amides having N-(meth)acryloyl groups.

[0094] Examples of chain-like amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-n-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. Another example is N-hydroxyethylacrylamide (HEAA). Examples of polymers containing chain-like amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by weight).

[0095] 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 polymers (PACMO). Typical examples of acryloylmorpholine polymers include homopolymers of N-acryloylmorpholine (ACMO) and copolymers of ACMO (for example, copolymers in which the copolymerization ratio of ACMO exceeds 50% by weight). In acryloylmorpholine polymers, the ratio of the number of moles of ACMO units to the total number of moles of repeating units is usually 50% or more, and is appropriately 80% or more (for example, 90% or more, typically 95% or more). It may also be an acryloylmorpholine-based polymer composed substantially of ACMO units.

[0096] 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 their salts, styrene-maleic anhydride copolymers, styrene sulfonic acid-maleic acid copolymers or their salts, 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 its salts, styrene-acrylic acid copolymers or their salts, styrene sulfonic acid-acrylic acid copolymers or their salts, 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 refers collectively to acrylic acid and methacrylic acid.

[0097] The weight-average molecular weight (Mw) of the water-soluble polymer P3 is, for example, 5 × 10⁻⁶. ３ That's all. 1 x 10 ４ It may be more than 5 x 10 ４ It may be more than 10 x 10 ４ The above is also acceptable: 20 x 10 ４ The above is also acceptable: 25 x 10 ４ The above is also acceptable: 30 x 10 ４ The above is also acceptable: 40 x 10 ４ The above is also acceptable: 45 x 10 ４ The above is also acceptable. The Mw of the water-soluble polymer P3 is typically 150 × 10 ４ The following is appropriate: 100 x 10 ４ The following is also acceptable: 80 x 10 ４ The following is also acceptable: 60 x 10 ４ (for example, 50 x 10) ４ The following may also be acceptable.

[0098] In some embodiments, the polishing composition substantially does not contain water-soluble polymers other than cellulose derivatives and modified polyvinyl alcohol polymers (e.g., acetalized polyvinyl alcohol), i.e., water-soluble polymer P3 as an optional component. With such a configuration, the effects of the present invention can be effectively exhibited while limiting the suppression of the polishing rate due to the use of water-soluble polymers. Here, "substantially free of water-soluble polymer P3" means at least intentionally omitting water-soluble polymer P3 from the polishing composition, and the content of water-soluble polymer P3 in the polishing composition is 1.0 × 10⁻⁶. －５ It may be less than or equal to a percentage by weight, such as 1.0 × 10 －６ It may be less than or equal to a percentage by weight, or even 0% by weight.

[0099] <Surfactants> The polishing compositions disclosed herein include surfactants. By using surfactants in addition to cellulose derivatives and modified polyvinyl alcohol polymer A, the quality of the polished surface can be further improved. Any surfactant can be anionic, cationic, nonionic, or amphoteric. Usually, anionic or nonionic surfactants are preferred. Nonionic surfactants are more preferred from the viewpoint of low foaming and ease of pH adjustment. Using nonionic surfactants tends to further improve the performance in suppressing defects (e.g., haze lines). Examples of nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyalkylene adducts); and copolymers of multiple types of oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, alternating copolymers). Surfactants can be used individually or in combination of two or more types.

[0100] 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 triblocks, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, polyoxyethylene Examples include layl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.Among the preferred surfactants are block copolymers of EO and PO (especially PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ethers). For the polyoxyethylene alkyl ether, those with an EO addition number of about 1 to 10 (e.g., about 3 to 8) are preferably used.

[0101] The molecular weight of the surfactant is, for example, less than 5000, preferably less than 3000, and more preferably 2900 or less. By using a surfactant with a molecular weight of less than 3000 (for example, 2900 or less), it is easier to obtain an abrasive composition with excellent defect suppression properties. In some preferred embodiments, the molecular weight of the surfactant is, for example, less than 2000, more preferably 1900 or less (for example, less than 1800), even more preferably 1500 or less, and may also be 1000 or less (for example, 500 or less). Furthermore, from the viewpoint of surface activity and other factors, the molecular weight of the surfactant is usually appropriate to be 200 or more, and preferably 250 or more (for example, 300 or more).

[0102] The more preferred range of molecular weight of a surfactant may also vary depending on the type of surfactant. For example, when using polyoxyethylene alkyl ether as a surfactant, its molecular weight is preferably less than 2000, more preferably 1900 or less (e.g., less than 1800), even more preferably 1500 or less, and may be 1000 or less (e.g., 500 or less). Also, when using a block copolymer of EO and PO as a surfactant, its weight-average molecular weight may be, for example, 500 or more, 1000 or more, even 1500 or more, 2000 or more, and even 2500 or more. The upper limit of the above weight-average molecular weight is, for example, less than 5000, preferably 4500 or less, and may be, for example, less than 4000 or less than 3500.

[0103] The molecular weight of the surfactant may be determined from the chemical formula, or it may be determined by the weight-average molecular weight obtained by the GPC method described above. For example, in the case of polyoxyethylene alkyl ethers, it is preferable to use the molecular weight determined from the chemical formula, and in the case of block copolymers of EO and PO, it is preferable to use the weight-average molecular weight obtained by the GPC method described above.

[0104] While not particularly limited, the amount of abrasive particles (typically silica particles) W Ａ The amount of surfactant W Ｓ The ratio of the weight basis (W Ｓ / W Ａ From the viewpoint of cleaning performance, etc., the ratio (W) is, for example, 100 or less, may be 10 or less, may be 5 or less, is appropriate to be 0.50 or less, preferably 0.10 or less, more preferably 0.05 or less, even more preferably 0.03 or less, particularly preferably 0.02 or less (for example 0.0156 or less), may be 0.01 or less, may be 0.005 or less, may be 0.004 or less, or 0.003 or less. From the viewpoint of better demonstrating the effect of the surfactant, the above ratio (W) Ｓ / W Ａ ) is suitable if it is 0.00001 or more, preferably 0.0001 or more, more preferably 0.0005 or more, may be 0.001 or more, or may be 0.002 or more.

[0105] While not particularly limited, the content of cellulose derivative (water-soluble polymer P1) W Ｐ１ The amount of surfactant W Ｓ The ratio (W Ｓ / W Ｐ１ The ratio (W) can be, for example, 0.001 or more on a weight basis, and from the viewpoint of suppressing defects, it is appropriate to set it to 0.005 or more, preferably 0.01 or more, more preferably 0.02 or more, and may also be 0.03 or more. In addition, in some embodiments, the above ratio (W) Ｓ / W Ｐ１The ratio (W) is based on weight and may be, for example, 10 or less, and from the viewpoint of defect suppression, 5 or less (for example, less than 3) is appropriate, preferably 1 or less, and more preferably 0.5 or less. In some embodiments, the above ratio (W) Ｓ / W Ｐ１ ) may be 0.4 or less, 0.3 or less, or 0.2 or less.

[0106] While not particularly limited, the content W of modified polyvinyl alcohol polymer A Ｐ２ The amount of surfactant W Ｓ The ratio (W Ｓ / W Ｐ２ The ratio (W) can be, for example, 0.001 or more based on weight, and from the viewpoint of defect suppression, it is appropriate to set it to 0.005 or more, preferably 0.10 or more, and may also be 0.50 or more. In addition, in some embodiments, the above ratio (W) Ｓ / W Ｐ２ The ratio (W) is based on weight and may be, for example, 50 or less, but from the viewpoint of defect suppression, 30 or less (for example, 20 or less) is appropriate, and preferably 15 or less. In some embodiments, the above ratio (W) Ｓ / W Ｐ２ ) may be 10 or less, 5 or less, 1 or less, and more preferably less than 1.

[0107] While not particularly limited, the total content of water-soluble polymers W Ｐ The amount of surfactant W Ｓ The ratio (W Ｓ / W Ｐ The ratio (W) can be, for example, 0.001 or more based on weight, and from the viewpoint of defect suppression, it is appropriate to set it to 0.005 or more, preferably 0.01 or more, and may also be 0.02 or more, or 0.04 or more. In addition, in some embodiments, the above ratio (W) Ｓ / W Ｐ The value of ) is based on weight and may be, for example, 10 or less, but from the viewpoint of suppressing defects, it is appropriate to be 1 or less (for example, less than 1), preferably 0.5 or less, more preferably 0.3 or less, and may be, for example, 0.1 or less, or even 0.05 or less.

[0108] <Water> As the water contained in the polishing composition disclosed herein, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc., can be preferably used. In order to avoid as much as possible the inhibition of the function of other components contained in the polishing composition, the water used preferably has a total content of transition metal ions of 100 ppb or less. For example, the purity of the water can be increased by operations such as removal of impurity ions with an ion exchange resin, removal of foreign matter with a filter, or distillation.

[0109] <Other Components> The polishing compositions disclosed herein may further contain, as necessary, known additives that can be used in polishing compositions (for example, polishing compositions used in the finishing polishing process of silicon wafers), such as organic acids, organic acid salts, inorganic acids, inorganic acid salts, chelating agents, preservatives, and antifungal agents, to the extent that the effects of the present invention are not significantly hindered.

[0110] Organic acids and their salts, as well as inorganic acids and their salts, can be used individually or in combination of two or more. 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 phosphate) (NTMP) and phosphonovutanetricarboxylic acid (PBTC). Examples of organic acid salts include alkali metal salts (sodium salts, potassium salts, lithium 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 salts include alkali metal salts (sodium salts, potassium salts, lithium salts, etc.) and ammonium salts of inorganic acids.

[0111] The above chelating agents may be used individually or in combination of two or more. Examples of the above chelating agents include aminocarboxylic acid-based chelating agents and organic phosphonic acid-based chelating agents. Preferred examples of chelating agents include, for example, ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Examples of the above preservatives and fungicides include isothiazolinoline compounds, parahydroxybenzoic acid esters, phenoxyethanol, etc.

[0112] The polishing compositions disclosed herein preferably contain substantially no oxidizing agents. This is because if an oxidizing agent is present in the polishing composition, when the polishing composition is supplied to a substrate (e.g., a silicon wafer), the surface of the substrate may be oxidized, forming an oxide film, which may reduce the polishing rate. A specific example of an oxidizing agent is hydrogen peroxide (H2). ２ O ２ Examples include sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate. It should be noted that a polishing composition being substantially free of oxidizing agents means that it is at least intentionally free of oxidizing agents. Therefore, a polishing composition that inevitably contains trace amounts of oxidizing agents (for example, a molar concentration of oxidizing agents 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) due to raw materials or manufacturing methods may be included in the concept of a polishing composition that is substantially free of oxidizing agents as defined herein.

[0113] <pH> The pH of the polishing compositions disclosed herein is typically 8.0 or higher, preferably 8.5 or higher, more preferably 9.0 or higher, even more preferably 9.3 or higher, for example 9.5 or higher. As the pH of the polishing composition increases, the polishing efficiency tends to improve. On the other hand, from the viewpoint of preventing the dissolution of abrasive grains (e.g., silica particles) and suppressing a decrease in mechanical polishing action, the pH of the polishing composition is appropriately 12.0 or lower, preferably 11.0 or lower, more preferably 10.8 or lower, and even more preferably 10.5 or lower.

[0114] In the technology disclosed herein, the pH of the polishing composition is measured using a pH meter (for example, a glass electrode type hydrogen ion concentration indicator (model number F-72) manufactured by Horiba, Ltd.). More specifically, a three-point calibration is performed using standard buffers (phthalate pH buffer pH: 4.01 (25°C), neutral phosphate pH buffer pH: 6.86 (25°C), carbonate pH buffer pH: 10.01 (25°C)), and then the glass electrode is immersed in the polishing composition to be measured for at least two minutes until the pH of the polishing composition stabilizes, after which the pH of the polishing composition is measured.

[0115] <Polishing Solution> The polishing compositions disclosed herein are typically supplied to an object to be polished in the form of a polishing solution and used for polishing the object. The polishing solution may be prepared, for example, by diluting (typically with water) any of the polishing compositions disclosed herein. In this case, the polishing composition corresponds to the stock solution (so-called concentrated solution) of the polishing solution. Alternatively, the polishing composition may be used as is as a polishing solution. Another example of a polishing solution is a polishing solution obtained by adjusting the pH of the polishing compositions disclosed herein. The content of each component in the polishing solution is described below, but in this specification, "content in the polishing solution" can be read as "content in the polishing composition".

[0116] The abrasive content in the polishing fluid is not particularly limited, and is preferably 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.10% by weight or more, for example 0.15% by weight or more, and may also be 0.20% by weight or more, 0.25% by weight or more, or 0.27% by weight or more. A higher polishing speed can be achieved by increasing the abrasive content. From the viewpoint of the dispersion stability of particles in the polishing fluid, the abrasive content in the polishing fluid is usually appropriate to be 10% by weight or less, preferably 7% by weight or less, more preferably 5% by weight or less, even more preferably 2% by weight or less, for example 1% by weight or less, and may also be 0.7% by weight or less. In a preferred embodiment, the abrasive content in the polishing fluid may be 0.5% by weight or less, or 0.4% by weight or less. This makes it easier to maintain surface quality.

[0117] The content of basic compounds in the polishing solution is not particularly limited. From the viewpoint of improving the polishing rate, etc., it is usually appropriate to have a content of 0.0005% by weight or more, preferably 0.001% by weight or more, more preferably 0.003% by weight or more, and even more preferably 0.005% by weight or more (for example, more than 0.005% by weight). Furthermore, from the viewpoint of improving surface quality, etc., it is appropriate to have a content of less than 0.5% by weight, preferably less than 0.1% by weight, more preferably less than 0.05% by weight, and even more preferably less than 0.03% by weight (for example, less than 0.025% by weight, and even more preferably less than 0.02% by weight).

[0118] The content of the cellulose derivative (water-soluble polymer P1) in the polishing solution is not particularly limited and may be, for example, 0.001% by weight or more, or 0.005% by weight or more. From the viewpoint of suppressing haze lines and improving wettability, in some embodiments, the above content is preferably 0.01% by weight or more, more preferably 0.012% by weight or more, and even more preferably 0.015% by weight or more (for example, 0.016% by weight or more). In addition, the content of the cellulose derivative in the polishing solution can be, for example, 1.0% by weight or less. From the viewpoint of obtaining a processing force suitable for a polishing process in which the polishing composition disclosed herein is used, in some embodiments, the above content is suitable to be 0.1% by weight or less, preferably 0.05% by weight or less, may be 0.026% by weight or less, may be 0.02% by weight or less, or may be 0.018% by weight or less.

[0119] The content of modified polyvinyl alcohol polymer A in the polishing solution is not particularly limited and may be, for example, 0.0001% by weight or more, or 0.0005% by weight or more. From the viewpoint of further suppressing the haze line, in some embodiments, the above content is preferably 0.001% by weight or more, more preferably 0.002% by weight or more, and even more preferably 0.003% by weight or more. In addition, the content of modified polyvinyl alcohol polymer A in the polishing solution can be, for example, 1.0% by weight or less. From the viewpoint of obtaining a processing force suitable for a polishing process in which the polishing composition disclosed herein is used, in some embodiments, the above content is suitable to be 0.1% by weight or less, preferably 0.05% by weight or less, may be 0.02% by weight or less, may be 0.01% by weight or less, or may be 0.008% by weight or less.

[0120] When an arbitrary water-soluble polymer (water-soluble polymer P3) is included, the content of the arbitrary water-soluble polymer in the polishing solution is not particularly limited and may be, for example, 0.0001% by weight or more, or 0.0005% by weight or more. From the viewpoint of improving surface quality, a preferred content is 0.001% by weight or more, more preferably 0.0015% by weight or more, and even more preferably 0.002% by weight or more. In addition, the content of the arbitrary water-soluble polymer in the polishing solution can be, for example, 1.0% by weight or less. From the viewpoint of obtaining processing power suitable for a polishing process in which the polishing composition disclosed herein is used, the content of the arbitrary water-soluble polymer is usually appropriate to be 0.5% by weight or less, preferably 0.1% by weight or less, may be 0.05% by weight or less, may be 0.02% by weight or less, may be 0.01% by weight or less, or may be 0% by weight.

[0121] The total content of water-soluble polymers in the polishing solution is not particularly limited and can be, for example, 0.0001% by weight or more. From the viewpoint of suppressing haze lines, a preferred content is 0.0005% by weight or more, more preferably 0.001% by weight or more, for example 0.003% by weight or more, and may also be 0.005% by weight or more, 0.008% by weight or more, or 0.01% by weight or more (for example, more than 0.01% by weight). Furthermore, from the viewpoint of improving the polishing rate, the total content of water-soluble polymers in the polishing solution is usually preferably 0.2% by weight or less, more preferably 0.1% by weight or less, and may also be 0.05% by weight or less (for example, 0.02% by weight or less).

[0122] The amount of surfactant in the polishing solution (the total amount if two or more surfactants are included) is not particularly limited. Typically, the amount of surfactant can be, for example, 0.00001% by weight or more from the viewpoint of cleaning performance, etc. From the viewpoint of improving surface quality (e.g., suppressing defects), etc., a preferred amount is 0.00005% by weight or more, and more preferably 0.0001% by weight or more. In some embodiments, the above amount may be 0.0002% by weight or more, 0.0005% by weight or more, or 0.0007% by weight or more. Furthermore, from the viewpoint of polishing rate, etc., in some embodiments, the above amount is preferably 0.1% by weight or less, more preferably 0.01% by weight or less, even more preferably 0.005% by weight or less, may be 0.003% by weight or less, may be 0.001% by weight or less, or may be 0.0005% by weight or less.

[0123] <Concentrated Solution> The polishing composition disclosed herein may be in a concentrated form (i.e., in the form of a concentrated polishing solution) before being supplied to the substrate. Such a concentrated solution is advantageous in terms of convenience and cost reduction during manufacturing, distribution, and storage. The concept of a concentrated solution in this specification includes the stock solution before dilution. The above-mentioned concentrated solution may be prepared as a stock solution. The concentration ratio of the concentrated solution is not particularly limited and can be, for example, 2 to 100 times in terms of volume, and is usually 5 to 50 times (for example, 10 to 40 times). Such a concentrated solution can be used in a manner in which a polishing solution (working slurry) is prepared by diluting it at a desired timing and supplying the polishing solution to the substrate. The above dilution can be performed, for example, by adding water to the concentrated solution and mixing it.

[0124] When the concentrated solution is diluted and used for polishing, the abrasive content in the concentrated solution can be, for example, 25% by weight or less. From the viewpoint of dispersion stability and filterability of the concentrated solution, the above content is usually preferably 20% by weight or less, and more preferably 15% by weight or less. In some preferred embodiments, the abrasive content may be 10% by weight or less, or 6% by weight or less. Furthermore, from the viewpoint of convenience and cost reduction during manufacturing, distribution, storage, etc., the abrasive content in the concentrated solution 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 (for example, more than 1% by weight).

[0125] In some embodiments, the content of the basic compound in the concentrate can be, for example, less than 15% by weight. From the viewpoint of storage stability, etc., the content is usually preferably 10% by weight or less (for example less than 10% by weight), more preferably 3% by weight or less, and may be 1% by weight or less (for example less than 1% by weight), or even 0.5% by weight or less. Furthermore, from the viewpoint of convenience and cost reduction during manufacturing, 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 0.05% by weight or more, and even more preferably 0.1% by weight or more.

[0126] In some embodiments, the content of the cellulose derivative (water-soluble polymer P1) in the concentrate may be, for example, 0.001% by weight or more, 0.01% by weight or more, 0.05% by weight or more, 0.1% by weight or more, or 0.2% by weight or more. From the viewpoint of storage stability, etc., the content is appropriately 3.0% by weight or less, for example, 2.0% by weight or less, 1.0% by weight or less, or 0.7% by weight or less.

[0127] In some embodiments, the content of the modified polyvinyl alcohol polymer A in the concentrate may be, for example, 0.0005% by weight or more, 0.001% by weight or more, 0.005% by weight or more, or 0.01% by weight or more. From the viewpoint of storage stability, etc., the content is appropriately 3.0% by weight or less, for example, 1.0% by weight or less, 0.1% by weight or less, or 0.05% by weight or less.

[0128] If an arbitrary water-soluble polymer (water-soluble polymer P3) is included, the content of the arbitrary water-soluble polymer in the concentrate may be, for example, 0.0005% by weight or more, 0.005% by weight or more, 0.01% by weight or more, 0.05% by weight or more, or 0.1% by weight or more. From the viewpoint of storage stability, etc., the content is appropriately 3.0% by weight or less, for example, 2.0% by weight or less, 1.0% by weight or less, 0.5% by weight or less, or 0% by weight.

[0129] The total content of water-soluble polymers in the concentrated solution may be, for example, 0.0005% by weight or more, 0.005% by weight or more, 0.01% by weight or more, 0.05% by weight or more, 0.1% by weight or more, or 0.2% by weight or more. From the viewpoint of storage stability, etc., the above content is appropriately 5.0% by weight or less, for example, 3.0% by weight or less, 2.0% by weight or less, 1.0% by weight or less, or 0.5% by weight or less.

[0130] The surfactant content in the concentrated solution 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 also be 0.05% by weight or less, or 0.025% by weight or less. The surfactant content in the above concentrated solution 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.

[0131] <Preparation of Polishing Composition> The polishing composition used in the art disclosed herein may be a single-component type or a multi-component type, including a two-component type. For example, the polishing composition may be configured such that a polishing solution is prepared by mixing part A, which contains at least abrasive grains, and part B, which contains at least a portion of the remaining components, and mixing and diluting these at appropriate times as needed.

[0132] 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 vane-type stirrer, an ultrasonic disperser, or a homomixer. The manner in which these components are mixed is not particularly limited; for example, all components may be mixed at once, or they may be mixed in an order set as appropriate.

[0133] <Applications> The polishing compositions in the technologies disclosed herein can be applied to polishing objects having various materials and shapes. The materials of the objects to be polished may be, for example, metals or metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, stainless steel, or alloys thereof; glassy materials such as quartz glass, aluminosilicate glass, and glassy carbon; ceramic materials such as alumina, silica, sapphire, silicon nitride, tantalum nitride, and titanium carbide; compound semiconductor substrate materials such as silicon carbide, gallium nitride, and gallium arsenide; resin materials such as polyimide resin; and so on. The objects to be polished may also be composed of multiple of these materials.

[0134] The polishing compositions in the art disclosed herein may be particularly preferred for polishing silicon surfaces (typically silicon wafers). Typical examples of silicon wafers are silicon single-crystal wafers, such as silicon single-crystal wafers obtained by slicing a silicon single-crystal ingot.

[0135] The polishing compositions disclosed herein can be preferably applied to the polishing process of an object to be polished (e.g., a silicon wafer). The object to be polished may have undergone general treatments that can be applied to the object to be polished in an upstream process, such as lapping or etching, prior to the polishing process with the polishing compositions disclosed herein.

[0136] The polishing compositions disclosed herein are effective when used in a finishing process of a substrate (e.g., a silicon wafer) or in a polishing process immediately preceding it, and are particularly preferred for use in a finishing polishing process. Here, a finishing polishing process refers to the final polishing process in the manufacturing process of the object (i.e., a process after which no further polishing is performed). The polishing compositions disclosed herein may also be used in polishing processes upstream of finishing polishing (referring to a preliminary polishing process between a rough polishing process and a final polishing process, which typically includes at least a primary polishing process and may further include secondary, tertiary, etc. polishing processes), for example, in a polishing process performed immediately before finishing polishing.

[0137] The polishing compositions disclosed herein are effective, for example, for polishing silicon wafers that have been prepared by an upstream process to a surface roughness of 0.01 nm to 100 nm (typically for finish polishing or polishing immediately preceding it). 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.

[0138] <Polishing> The polishing compositions disclosed herein can be used to polish an object to be polished in a manner that includes, for example, the following operations. A preferred embodiment of a method for polishing an object to be polished (e.g., a silicon wafer) using the polishing compositions disclosed herein will be described below. That is, a polishing solution is prepared using any of the polishing compositions disclosed herein. Preparing the polishing solution may include preparing the polishing solution by adding operations such as concentration adjustment (e.g., dilution) and pH adjustment to the polishing composition. Alternatively, the polishing composition may be used as is as the polishing solution.

[0139] Next, the polishing solution is supplied to the object to be polished, 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 preliminary polishing process is set in a general polishing apparatus, and the polishing solution is supplied to the surface of the silicon wafer to be polished through the polishing pad of the apparatus. Typically, while continuously supplying the polishing solution, the polishing pad is pressed against the surface of the silicon wafer to be polished, and the two are moved relative to each other (for example, by rotation). Through this polishing process, the polishing of the object to be polished is completed.

[0140] The polishing pad used in the above polishing process is not particularly limited. For example, polishing pads of foamed polyurethane type, nonwoven fabric type, suede type, etc., can be used. Each polishing pad may or may not contain abrasive grains. Generally, polishing pads that do not contain abrasive grains are preferred.

[0141] The workpiece polished using the polishing composition disclosed herein is typically cleaned. Cleaning can be performed using a suitable cleaning solution. The cleaning solution used is not particularly limited, and for example, SC-1 cleaning solution (ammonium hydroxide (NH4)), which is common in fields such as semiconductors, can be used. ４ OH) and hydrogen peroxide (H ２ O ２ ) and water (H ２ (O) Mixture with SC-2 washing solution (HCl and H ２ O ２ and H ２A mixture of O, ozonated water cleaning solution, hydrofluoric acid cleaning solution, etc., can be used. The temperature of the cleaning solution can be in the range of room temperature (typically about 15°C to 25°C) or higher, and up 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.

[0142] The matters disclosed in this specification include: (1) an abrasive composition comprising abrasive grains, a basic compound, a cellulose derivative, a modified polyvinyl alcohol polymer A, a surfactant, and water, wherein the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A is 90,000 or less. (2) the abrasive composition according to (1), wherein the surfactant comprises a nonionic surfactant. (3) the content W of the modified polyvinyl alcohol polymer A in the abrasive composition. Ｐ２ Based on [weight %] and the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A, the following formula applies: P = W Ｐ２ A polishing composition according to [1] or [2] above, wherein the value of parameter P calculated by ×Mw is 2 or more and 100 or less. [4] A polishing composition according to any one of [1] to [3] above, wherein the weight-based content ratio of the modified polyvinyl alcohol polymer A to the abrasive grains is 0.0001 or more. [5] A polishing composition according to any one of [1] to [4] above, wherein the weight-based content ratio of the cellulose derivative to the abrasive grains is greater than 0.06. [6] A polishing composition according to any one of [1] to [5] above, wherein the weight-based content ratio of the surfactant to the abrasive grains is 0.10 or less. [7] A polishing composition according to any one of [1] to [6] above, wherein the weight-based content ratio of the surfactant to the modified polyvinyl alcohol polymer A is less than 1. [8] A polishing composition according to any one of [1] to [7] above, comprising silica particles as the abrasive grains. [9] A concentrated solution of the polishing composition according to any one of [1] to [8].

[10] A polishing method comprising polishing a surface made of a silicon material using the polishing composition described in any of [1] to [8] above.

[0143] The following describes some embodiments of the present invention, but the present invention is not intended to be limited to those shown in these embodiments.

[0144] (Example 1) A concentrated solution of the polishing composition according to this example was prepared using abrasive grains, a basic compound, a cellulose derivative, a modified polyvinyl alcohol polymer (abbreviated as "modified PVA" in Table 1), 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 cellulose derivative had a weight-average molecular weight (Mw) of approximately 25 × 10⁻¹⁶. ４ Hydroxyethylcellulose (HEC) was used. As the modified polyvinyl alcohol polymer, acetalized polyvinyl alcohol (Ac-PVA) with a degree of acetalization of 24% and a Mw of approximately 9700 was used. As the surfactant, polyoxyethylene decyl ether (C10EO5) with 5 moles of ethylene oxide added was used. By diluting the concentrated solution of the obtained polishing composition with deionized water at a volume ratio of 20, a polishing composition according to this example was obtained containing 0.275% by weight of abrasive particles, 0.01% by weight of a basic compound, 0.017% by weight of HEC, 0.0009% by weight of acetalized polyvinyl alcohol, and 0.0008% by weight of the surfactant.

[0145] (Examples 2-4) Polishing compositions for each example were prepared in the same manner as in Example 1, except that the HEC content, acetalized polyvinyl alcohol content, and surfactant content were as shown in Table 1.

[0146] (Example 5) As the modified polyvinyl alcohol polymer, a graft copolymer (hereinafter also referred to as "PVA-g-PEO") was used, which had polyvinyl alcohol (PVA) with a degree of saponification of 95% or more as the main chain and polyethylene oxide (PEO) as the side chain, and had a Mw of approximately 4400. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned PVA-g-PEO was used as the modified polyvinyl alcohol polymer.

[0147] (Example 6) As the modified polyvinyl alcohol polymer, PVA-g-PEO, a graft copolymer having polyvinyl alcohol (PVA) with a degree of saponification of 95% or more as the main chain and polyethylene oxide (PEO) as the side chain, was used. In this example, PVA-g-PEO with a Mw of approximately 16,000 was used. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned PVA-g-PEO was used as the modified polyvinyl alcohol polymer.

[0148] (Example 7) As the modified polyvinyl alcohol polymer, PVA-g-PEO, a graft copolymer having polyvinyl alcohol (PVA) with a degree of saponification of 95% or more as the main chain and polyethylene oxide (PEO) as the side chain, was used. In this example, PVA-g-PEO with a PEO content of about 14 to 17 mol% and a Mw of about 19,000 was used. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned PVA-g-PEO was used as the modified polyvinyl alcohol polymer.

[0149] (Example 8) As the modified polyvinyl alcohol polymer, a copolymer of vinyl alcohol and N-vinylpyrrolidone (hereinafter also referred to as "PVP-PVA") was used. In this example, a random copolymer was used, in which the molar ratio of VA units to VP units contained in the above PVP-PVA was 85:15 and Mw was approximately 6500. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above PVP-PVA was used as the modified polyvinyl alcohol polymer.

[0150] (Example 9) PVP-PVA was used as the modified polyvinyl alcohol polymer. In this example, a random copolymer PVP-PVA with Mw of approximately 19,000 was used. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned PVP-PVA was used as the modified polyvinyl alcohol polymer.

[0151] (Example 10) PVP-PVA was used as the modified polyvinyl alcohol polymer. In this example, a random copolymer PVP-PVA with Mw of approximately 59,000 was used. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned PVP-PVA was used as the modified polyvinyl alcohol polymer.

[0152] (Example 11) Hydrocarbon-modified PVA was used as the modified polyvinyl alcohol polymer. The hydrocarbon-modified PVA used in this example is one in which some of the hydroxyl groups in the PVA main chain are replaced with hydrocarbon-containing groups such as alkyl groups, alkyl ether groups, and aromatic groups. However, the hydrocarbon-modified PVA used in this example is not modified PVA obtained by an acetalization reaction. In this example, hydrocarbon-modified PVA with Mw of approximately 29,000 was used. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above-mentioned hydrocarbon-modified PVA was used as the modified polyvinyl alcohol polymer.

[0153] (Example 12) An abrasive composition according to this example was prepared in the same manner as in Example 1, except that a modified polyvinyl alcohol-based polymer was not used.

[0154] (Example 13) As the modified polyvinyl alcohol polymer, a copolymer of vinyl alcohol and N-acryloylmorpholine (hereinafter, the copolymer of vinyl alcohol and N-acryloylmorpholine will also be referred to as "PACMO-PVA") was used. In this example, PACMO-PVA was used in which the proportion of ACMO units contained in the above PACMO-PVA was 76 mol%, and Mw was approximately 170,000. The polishing composition according to this example was prepared in the same manner as in Example 1, except that the above PACMO-PVA was used as the modified polyvinyl alcohol polymer.

[0155] <Polishing of Silicon Wafers> The details of the pre-polishing process applied to each example are shown below. (Pre-polishing process) A pre-polishing composition was prepared containing 0.48% by weight of abrasive grains and 0.07% by weight of a basic compound, with the remainder being water. Colloidal silica with an average primary particle diameter of 35 nm was used as the abrasive grains. Tetramethylammonium hydroxide (TMAH) was used as the basic compound. This pre-polishing composition was used as a polishing solution (working slurry) to polish a silicon wafer, which was the object to be polished, under the following pre-polishing conditions. A commercially available silicon single-crystal wafer with a diameter of 300 mm, which had been lapped and etched, was used as the silicon wafer (conductivity type: P-type, crystal orientation: <100>, resistivity: 1 Ω・cm or more and less than 100 Ω・cm, COP-free).

[0156] [Pre-polishing conditions] Polishing equipment: Single-wafer polishing machine manufactured by Okamoto Machine Tool Works, model "PNX-332B" Polishing load: 12 kPa Plate rotation speed: 51 rpm Head (carrier) rotation speed: 50 rpm Polishing pad: Polishing pad manufactured by Fujibo Ehime, product name "POLYPAS275NX" Polishing fluid supply rate: 1.5 liters / min Polishing fluid temperature: 20℃ Plate cooling water temperature: 20℃ Polishing time: 3 minutes

[0157] (Finishing Polishing Process) The polishing composition for each example was used as is as a polishing liquid (working slurry), and the silicon wafer that had completed the above preliminary polishing process was polished under the following finishing polishing conditions.

[0158] [Finishing Polishing Conditions] Polishing equipment: Single-wafer polishing machine manufactured by Okamoto Machine Tool Works, model "PNX-332B" Polishing load: 12 kPa Plate rotation speed: 51 rpm Head (carrier) rotation speed: 50 rpm Polishing pad: Polishing pad manufactured by Fujibo Ehime, product name "POLYPAS275NX" Polishing fluid supply rate: 1.5 liters / min Polishing fluid temperature: 20℃ Plate cooling water temperature: 20℃ Polishing time: 6 minutes

[0159] Afterward, the polished silicon wafers were removed from the polishing apparatus. The removed silicon wafers were then cleaned using a single-wafer cleaning apparatus. First, the silicon wafers were cleaned with ozonated water cleaning solution for 60 seconds, and then cleaned with SC-1 cleaning solution and a brush for 110 seconds. Next, the silicon wafers were cleaned with ozonated water cleaning solution for 20 seconds, and then with hydrofluoric acid cleaning solution for 15 seconds. This ozonated water cleaning and hydrofluoric acid cleaning was considered one set, and a total of three sets of cleaning were performed on the silicon wafers. After cleaning, the silicon wafers were further cleaned with ozonated water cleaning solution for 20 seconds. After that, the silicon wafers were dried.

[0160] <Measurement and Evaluation> (Haze Lines) For the cleaned silicon wafers, the total area of ​​haze lines present within the observation area excluding the edge portion (5 mm) from the entire cleaned silicon wafer was measured using a wafer inspection device manufactured by KLA-Tencor, product name "Surfscan SP5," in the DNO mode of the device. The obtained results were converted to a relative value [%] with the total area in Example 12 set to 100%. The smaller this relative value [%], the more the haze lines are suppressed. The results are shown in the corresponding column of Table 1.

[0161] (Wettability) The longest radial distance (water-repellent distance) [mm] from the edge of the silicon wafer was measured when the polished silicon wafer was unloaded. A smaller water-repellent distance indicates better wettability. The results are shown in the corresponding column of Table 1.

[0162]

[0163] As shown in Table 1, the polishing compositions of Examples 1 to 11, which contain abrasive grains, a cellulose derivative, a modified polyvinyl alcohol polymer with a weight-average molecular weight of 90,000 or less, a surfactant, and water, were found to have better wettability of the surface after polishing and to effectively suppress haze lines compared to the polishing composition of Example 12, which contains a cellulose derivative but does not use a modified polyvinyl alcohol polymer. Furthermore, the polishing composition of Example 13, which uses a modified polyvinyl alcohol polymer with a weight-average molecular weight greater than 90,000 along with the cellulose derivative, was found to have a tendency to worsen haze lines compared to the polishing compositions of Examples 1 to 11, which use a modified polyvinyl alcohol polymer with a weight-average molecular weight of 90,000 or less.

[0164] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above.

Claims

1. An abrasive composition comprising abrasive grains, a basic compound, a cellulose derivative, a modified polyvinyl alcohol polymer A, a surfactant, and water, wherein the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A is 90,000 or less.

2. The polishing composition according to claim 1, wherein the surfactant comprises a nonionic surfactant.

3. The amount of the modified polyvinyl alcohol polymer A in the polishing composition W Ｐ２ Based on [weight %] and the weight-average molecular weight Mw of the modified polyvinyl alcohol polymer A, the following formula applies: P = W Ｐ２ The polishing composition according to claim 1 or 2, wherein the value of parameter P calculated by ×Mw is 2 or more and 100 or less.

4. The polishing composition according to claim 1 or 2, wherein the weight-based content ratio of the modified polyvinyl alcohol-based polymer A to the abrasive grains is 0.0001 or more.

5. The polishing composition according to claim 1 or 2, wherein the weight-based content ratio of the cellulose derivative to the abrasive grains is greater than 0.

06.

6. The polishing composition according to claim 1 or 2, wherein the weight-based content ratio of the surfactant to the abrasive grains is 0.10 or less.

7. The polishing composition according to claim 1 or 2, wherein the weight-based content ratio of the surfactant to the modified polyvinyl alcohol polymer A is less than 1.

8. The polishing composition according to claim 1 or 2, comprising silica particles as the abrasive grains.

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

10. A polishing method comprising polishing a surface made of a silicon material using the polishing composition described in claim 1 or 2.

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