Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09G—POLISHING COMPOSITIONS; SKI WAXES
  • C09G1/00—Polishing compositions
  • C09G1/02—Polishing compositions containing abrasives or grinding agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K3/00—Materials not provided for elsewhere
  • C09K3/14—Anti-slip materials; Abrasives
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices

Definitions

• the present invention relates to a polishing composition.
• This application claims priority to Japanese Patent Application No. 2023-44298, filed on March 20, 2023, the entire contents of which are incorporated herein by reference.
• polishing process includes, for example, a preliminary polishing process (preliminary polishing process) and a final polishing process (final polishing process).
• the preliminary polishing process includes, for example, a rough polishing process (primary polishing process) and an intermediate polishing process (secondary polishing process).
• Technical documents related to the polishing compositions used in the polishing process include, for example, Patent Documents 1 to 3.
• a silicon wafer may be irradiated with a laser beam on the front or back surface of the silicon wafer to give it a mark such as a barcode, number, or symbol (hard laser mark; hereinafter sometimes referred to as "HLM").
• HLM hard laser mark
• the application of the HLM is generally performed after the lapping process of the silicon wafer is completed and before the polishing process is started.
• the irradiation of the laser beam for applying the HLM causes an altered layer to form on the surface of the silicon wafer around the HLM.
• the HLM portion of the silicon wafer itself is not used in the final product, if the altered layer is not properly polished in the polishing process after the HLM is applied, it may become a protuberance and reduce the yield.
• the altered layer is altered by the energy of the laser beam and is difficult to polish. For this reason, in recent years, there has been a particular demand for a silicon wafer polishing composition that flattens the protuberance (hereinafter also simply referred to as "protuberance”) on the periphery of the HLM.
• protuberance flattens the protuberance
• the areas other than the peripheral area of the HLM that are easily polished may be polished more selectively than the areas of the peripheral area of the HLM that are difficult to polish, resulting in a situation in which it is difficult to improve the elimination of the protrusions. Therefore, in order to flatten the protrusions of the peripheral area of the HLM, it is effective to proceed with polishing while maintaining appropriate workability while appropriately protecting the surface to be polished, including the areas other than the peripheral area of the HLM that are easily polished.
• polishing compositions containing abrasive grains and water-soluble polymers are studied.
• water-soluble polymers act mainly on the surface to be polished and/or the surface of the abrasive grains, and have the function of protecting the surface to be polished from physical or chemical polishing.
• the present invention was made in consideration of these points, and aims to provide a polishing composition that can improve the ability to eliminate protuberances around the HLM.
• the inventors discovered that by using a water-soluble polymer with a specific structure in addition to a conventional water-soluble polymer, the protective function of each water-soluble polymer can be utilized to effectively protect the surface to be polished from polishing, thereby relatively facilitating the processing of the altered layer around the HLM.
• a polishing composition comprising an abrasive grain, a basic compound, a water-soluble polymer A, a water-soluble polymer B, and water.
• the water-soluble polymer A is represented by the following general formula (1): (wherein R1 is a hydrocarbon group having 5 or less carbon atoms, and R2 is a hydrogen atom or a hydrocarbon group having 3 or less carbon atoms).
• eliminating the protrusion around the HLM refers to reducing the height from the reference surface (reference plane) around the HLM of the substrate to be polished (typically a semiconductor substrate having a surface made of silicon material, such as a silicon wafer) to the highest point of the protrusion.
• the height from the reference surface around the HLM of the substrate to the highest point of the protrusion can be measured, for example, by the method described in the examples below.
• the water-soluble polymer B is a polymer that does not have a cellulose structure in its molecule.
• a polymer that does not have a cellulose structure in its molecule is used as the water-soluble polymer B, it tends to be easier to obtain good dispersion stability compared to, for example, cellulose derivatives.
• the water-soluble polymer B is a polymer that does not have a tertiary amine structure.
• the effects of the present invention can be preferably exhibited.
• the water-soluble polymer B is a polymer containing a tertiary amide group.
• the water-soluble polymer B is polyvinylpyrrolidone.
• the polishing composition contains a quaternary ammonium as the basic compound.
• a polishing composition containing a quaternary ammonium as the basic compound is preferable in terms of improving the polishing rate and eliminating bumps. The above composition makes it easy to achieve both an improved polishing rate and the elimination of bumps around the HLM.
• the polishing composition further contains a chelating agent.
• a polishing composition containing a chelating agent can suppress metal contamination of the polished surface after polishing.
• the polishing composition contains silica particles as the abrasive grains.
• silica particles as the abrasive grains, it is possible to effectively eliminate the protuberances around the HLM while maintaining the polishing rate.
• the polishing composition is used for pre-polishing a surface made of a silicon material.
• the polishing composition is used for pre-polishing a surface made of a silicon material, it is possible to improve the elimination of protuberances around the HLM.
• the polishing composition may be a concentrate.
• the polishing compositions disclosed herein may be manufactured, distributed, and stored as concentrates.
• a polishing method includes polishing a surface made of a silicon material with the polishing composition.
• the polishing method can improve the elimination of protuberances around the HLM.
• the polishing composition disclosed herein contains abrasive grains.
• the material and properties of the abrasive grains are not particularly limited, and can be appropriately selected according to the use mode of the polishing composition.
• Examples of abrasive grains include inorganic particles, organic particles, and organic-inorganic composite particles.
• 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; carbonates such as calcium carbonate and barium carbonate, and the like.
• organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles, and polyacrylonitrile particles.
• PMMA polymethyl methacrylate
• (meth)acrylic acid refers to acrylic acid and methacrylic acid in a comprehensive sense.
• the abrasive grains can be used alone or in combination of two or more types.
• the abrasive grains are preferably inorganic particles, and in particular, particles made of metal or semi-metal oxides.
• a suitable example of an abrasive grain that can be used in the technology disclosed herein is silica particles.
• the technology disclosed herein can be preferably implemented, for example, in an embodiment in which the abrasive grains are essentially made of silica particles.
• 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 that make up the abrasive grains are silica particles.
• silica particles is not particularly limited and can be selected as appropriate.
• Silica particles may be used alone or in combination of two or more types.
• Examples of silica particles include colloidal silica, fumed silica, precipitated silica, etc. Colloidal silica is particularly preferred because it is less likely to cause scratches on the surface of the object to be polished and can exhibit good polishing performance (performance of reducing surface roughness, etc.).
• the type of colloidal silica is not particularly limited and can be selected as appropriate. Colloidal silica may be used alone or in combination of two or more types.
• colloidal silica examples include colloidal silica produced by the ion exchange method using water glass (sodium silicate) as a raw material and alkoxide method colloidal silica.
• alkoxide method colloidal silica is colloidal silica produced by the hydrolysis and condensation reaction of alkoxysilane.
• the abrasive grains contained in the polishing composition may be in the form of primary particles, or in the form of secondary particles formed by association of multiple primary particles. Abrasive grains in the form of primary particles and abrasive grains in the form of secondary particles may also be present together. In some preferred embodiments, at least a portion of the abrasive grains are contained in the polishing composition in the form of secondary particles.
• the average primary particle diameter of the abrasive grains is not particularly limited, but from the viewpoint of maintaining the polishing rate while improving the ability to eliminate bumps, it is preferably 5 nm or more, more preferably 10 nm or more, and particularly preferably 20 nm or more. From the viewpoint of obtaining a higher polishing effect, the average primary particle diameter is preferably 25 nm or more, and even more preferably 30 nm or more. Abrasive grains having an average primary particle diameter of 40 nm or more may be used. In some embodiments, the average primary particle diameter may be, for example, more than 40 nm, more than 45 nm, or more than 50 nm.
• the average primary particle diameter of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 120 nm or less, and particularly preferably 100 nm or less. In some embodiments, the average primary particle diameter may be 75 nm or less, or may be 60 nm or less.
• the specific surface area can be measured using, for example, a surface area measuring device manufactured by Micromeritics, under the product name "Flow Sorb II 2300".
• the average secondary particle diameter of the abrasive grains is not particularly limited, and may be appropriately selected, for example, from a range of about 15 nm to 300 nm. From the viewpoint of improving the ability to eliminate bumps, 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, 45 nm or more, preferably 50 nm or more, further 60 nm or more, 65 nm or more (for example, 70 nm or more), or 75 nm or more.
• the average secondary particle diameter is usually advantageously 250 nm or less, preferably 200 nm or less, and more preferably 150 nm or less. In some embodiments, the average secondary particle diameter may be 120 nm or less, or 110 nm or less.
• the average secondary particle size of the abrasive grains refers to the particle size measured by dynamic light scattering. For example, it can be measured using an Otsuka Electronics Co., Ltd. model "FPAR-1000" or an equivalent.
• the shape (external shape) 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, confetti-shaped, and rugby ball-shaped.
• the average aspect ratio of the abrasive grains is not particularly limited.
• the average aspect ratio of the abrasive grains is in principle 1.0 or more, and can be 1.05 or more, 1.10 or more, and may be 1.15 or more.
• the polishing rate tends to improve as the average aspect ratio increases.
• the average aspect ratio of the abrasive grains is greater than 1.2 (specifically, greater than 1.20), and may be, for example, 1.22 or more.
• Abrasive grains having an average aspect ratio of greater than 1.2 are typical examples of the above-mentioned non-spherical abrasive grains.
• the average aspect ratio of the abrasive grains is preferably 3.0 or less, and more preferably 2.0 or less, from the viewpoint of reducing scratches and improving polishing stability.
• the average aspect ratio of the abrasive grains may be, for example, 1.5 or less, 1.4 or less, or 1.3 or less.
• the shape (outer shape) and average aspect ratio of the abrasive grains can be ascertained, for example, by observation with an electron microscope.
• a specific procedure for ascertaining the average aspect ratio is, for example, to use a scanning electron microscope (SEM) to draw the smallest rectangle circumscribing each particle image for a predetermined number (e.g., 200) of abrasive grains whose individual particle shapes can be recognized. Then, for the rectangle drawn for each particle image, the long side length (long axis value) is divided by the short side length (short axis value) to calculate the long axis/short axis ratio (aspect ratio).
• the average aspect ratio can be found by arithmetically averaging the aspect ratios of the predetermined number of particles.
• the content of the abrasive grains is not particularly limited and can be appropriately set according to the purpose.
• the content of the abrasive grains relative to the total weight of the polishing composition may be, for example, 0.01% by weight or more, 0.05% by weight or more, or 0.1% by weight or more.
• the polishing rate tends to improve, and the HLM protuberance elimination property generally tends to improve.
• the content of the abrasive grains may be 0.2% by weight or more, 0.5% by weight or more, or 0.6% by weight or more.
• the content of the abrasive grains may be, for example, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1.5% by weight or less, 1.2% by weight or less, or 1.0% by weight or less.
• the HLM protuberance elimination property is likely to be improved. For this reason, it is particularly meaningful to apply the present invention to compositions with a low abrasive concentration.
• the content of the abrasive may be less than 1.0% by weight, 0.8% by weight or less, 0.6% by weight or less, 0.5% by weight or less, 0.4% by weight or less, or 0.35% by weight or less. These contents can be preferably applied to the content in the polishing liquid (working slurry) supplied to the object to be polished, for example.
• the content of abrasive grains is usually 50% by weight or less, and more preferably 40% by weight or less, from the viewpoints of storage stability, filterability, etc.
• the content of abrasive grains is preferably 1% by weight or more, and more preferably 5% by weight or more.
• the polishing composition disclosed herein contains a basic compound.
• the basic compound refers to a compound that has the function of increasing the pH of the polishing composition by being added to the polishing composition.
• the basic compound acts to chemically polish the surface to be polished, and can contribute to improving the polishing rate.
• the basic compound may be an organic basic compound or an inorganic basic compound.
• the basic compound may be used alone or in combination of two or more.
• organic basic compounds include quaternary ammonium salts such as tetraalkylammonium salts.
• the anion in the ammonium salts may be, for example, OH - , F - , Cl - , Br - , I - , ClO 4 - , BH 4 - , HCO 3 - , etc.
• quaternary ammonium salts such as choline, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetramethylammonium hydrogen carbonate may be preferably used.
• tetramethylammonium hydroxide is preferred.
• organic basic compounds include quaternary phosphonium salts such as tetraalkylphosphonium salts.
• the anion in the phosphonium salts may be, for example, OH - , F - , Cl - , Br - , I - , ClO 4 - , BH 4 - , HCO 3 - , etc.
• halides or hydroxides such as tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, etc. may be preferably used.
• organic basic compound examples include amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-( ⁇ -aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, and triethylenetetramine; piperazines such as 1-(2-aminoethyl)piperazine and N-methylpiperazine; azoles such as imidazole and triazole; guanidine; and the like.
• inorganic basic compounds include ammonia; hydroxides of ammonia, alkali metals, or alkaline earth metals; carbonates of ammonia, alkali metals, or alkaline earth metals; hydrogen carbonates of ammonia, alkali metals, or alkaline earth metals, etc.
• specific examples of the above hydroxides include lithium hydroxide, potassium hydroxide, sodium hydroxide, etc.
• Specific examples of the above carbonates or hydrogen carbonates include ammonium hydrogen carbonate, ammonium carbonate, lithium hydrogen carbonate, lithium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, sodium carbonate, etc.
• Preferred basic compounds include ammonia, lithium hydroxide, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ammonium hydrogen carbonate, ammonium carbonate, lithium hydrogen carbonate, lithium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, and sodium carbonate.
• preferred ones are ammonia, lithium hydroxide, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, lithium carbonate, and potassium carbonate.
• Preferred basic compounds from the viewpoint of improving the ability to eliminate bumps include quaternary ammoniums (quaternary ammonium salts).
• One type of quaternary ammonium may be used alone, or two or more types may be used in combination. Tetramethylammonium hydroxide is particularly preferably used. From the viewpoint of improving the polishing rate, the use of carbonates such as potassium carbonate is preferred.
• quaternary ammoniums e.g., tetramethylammonium hydroxide
• carbonates e.g., potassium carbonate
• hydroxides of alkali metals or alkaline earth metals e.g., potassium hydroxide are preferably used.
• the ratio of these components used is not particularly limited, and can be set to an appropriate range that achieves a good balance between polishing rate maintenance and protuberance elimination, depending on the concentrations of other components such as abrasive grains and water-soluble polymers.
• the content of the basic compound relative to the total amount of the polishing composition is preferably 0.005% by weight or more, more preferably 0.01% by weight or more, and even more preferably 0.03% by weight or more, from the viewpoint of the polishing rate and the ability to eliminate bumps.
• Increasing the content of the basic compound can also improve stability.
• the upper limit of the content of the basic compound is appropriately set to 5% by weight or less, and from the viewpoint of surface quality, etc., it is preferably 2% by weight or less, more preferably 1% by weight or less, and even more preferably 0.5% by weight or less, and may be 0.4% by weight or less, 0.3% by weight or less, or 0.2% by weight or less (for example, less than 0.2% by weight).
• the above content refers to the total content of two or more types of basic compounds. These contents can be preferably applied to the content in the polishing liquid (working slurry) supplied to the polishing object, for example.
• the content of the basic compound is usually 10% by weight or less, and more preferably 5% by weight or less (e.g., 4% by weight or less), from the viewpoints of storage stability, filterability, etc.
• the content of the basic compound is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and even more preferably 0.9% by weight or more (e.g., 1.5% by weight or more).
• the weight ratio (C T /C S ) of the content C T of the basic compound to the content C S of the abrasive grains in the polishing composition is not particularly limited as long as the effect of the technology disclosed herein is exhibited.
• the ratio (C T /C S ) is, for example, appropriate to be about 0.005 or more, and from the viewpoint of effectively exhibiting the effect of adding the basic compound, it is preferably 0.01 or more, more preferably 0.02 or more, and may be, for example, 0.05 or more.
• the ratio (C T /C S ) is, for example, appropriate to be about 1 or less, preferably 0.8 or less, more preferably 0.6 or less, and may be, for example, 0.5 or less, 0.4 or less, 0.3 or less, or 0.2 or less (for example, less than 0.2).
• the polishing composition disclosed herein is characterized by containing two or more water-soluble polymers as water-soluble polymers. Specifically, the polishing composition contains a water-soluble polymer A and a water-soluble polymer B.
• the water-soluble polymer A contained in the polishing composition disclosed herein has a repeating unit represented by the following general formula (1): (wherein R 1 is a hydrocarbon group having 5 or less carbon atoms, and R 2 is a hydrogen atom or a hydrocarbon group having 3 or less carbon atoms).
• a polishing composition containing the water-soluble polymer A including the structural unit described above together with the water-soluble polymer B described below can effectively eliminate the ridges around the HLM.
• the water-soluble polymer A and the water-soluble polymer B each exhibit different predetermined adsorption properties to the object to be polished (typically the surface of a hydrophobic silicon material), and are believed to be mainly adsorbed to the surface of the material other than the HLM periphery, suppressing the polishing action (processing force) of the abrasive grains and the basic compound.
• the processability of the ridges around the HLM periphery is relatively increased, and the ridges around the HLM periphery are believed to be effectively eliminated.
• the water-soluble polymer A may be used alone or in combination of two or more types.
• R 1 is a straight-chain or branched hydrocarbon group having 1 to 5 carbon atoms.
• the hydrocarbon group having 1 to 5 carbon atoms represented by R 1 include alkyl groups such as methyl, ethyl, propyl, and butyl; alkenyl groups such as ethenyl and propenyl; alkynyl groups such as ethynyl and propynyl; and cycloalkyl groups such as cyclopentyl.
• alkyl and alkynyl groups are preferred, and alkyl groups are more preferred.
• methyl, ethyl, and ethenyl (vinyl) groups are more preferred, and methyl and ethyl groups are even more preferred.
• R2 is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 3 carbon atoms.
• the hydrocarbon group having 1 to 3 carbon atoms represented by R2 include those having 1 to 3 carbon atoms among those exemplified as the hydrocarbon group having 1 to 5 carbon atoms represented by R1.
• R2 is more preferably a hydrogen atom or a methyl group, and further preferably a hydrogen atom.
• the structural unit represented by the above general formula (1) may be one type or two or more types.
• Water-soluble polymer A containing the structural unit represented by the above general formula (1) is a water-soluble polymer containing a secondary amide group in the repeating unit.
• water-soluble polymer A is used together with water-soluble polymer B, the protuberance of the peripheral portion of the HLM tends to be effectively eliminated.
• the water-soluble polymer A may be a homopolymer whose main chain is composed mainly of the structural unit represented by the above general formula (1), or may be a copolymer containing the structural unit represented by the above general formula (1) and other structural units.
• copolymer refers collectively to various types of copolymers such as random copolymers, alternating copolymers, block copolymers, and graft copolymers.
• the water-soluble polymer A is a polymer having an N-vinyl type monomer as the main repeating unit, i.e., an N-vinyl polymer.
• An example of an N-vinyl type monomer is an N-vinyl chain amide.
• a specific example of an N-vinyl chain amide is N-vinyl acetamide (NVA).
• the water-soluble polymer A is a homopolymer or copolymer (e.g., a copolymer in which the copolymerization ratio of N-vinyl linear amide exceeds 50% by weight) of an N-vinyl linear amide (typically N-vinyl acetamide).
• the content of repeat units derived from N-vinyl linear amide in the water-soluble polymer A is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more.
• Substantially all of the water-soluble polymer A may be repeat units derived from N-vinyl linear amide.
• a nonionic polymer can be preferably used as the water-soluble polymer A.
• electrostatic adsorption between the abrasive grains (typically silica particles) and the water-soluble polymer can be suppressed, and gelation of the composition can be suppressed.
• poly-N-vinylacetamide can be used as the water-soluble polymer A.
• PNVA poly-N-vinylacetamide
• Using PNVA as the water-soluble polymer A together with the water-soluble polymer B tends to improve the ability to eliminate protuberances around the HLM.
• the weight average molecular weight (Mw) of the water-soluble polymer A is not particularly limited.
• the Mw of the water-soluble polymer A may be, for example, approximately 200 ⁇ 10 4 or less, and is suitably approximately 150 ⁇ 10 4 or less. From the viewpoint of cleaning properties, etc., it is preferably approximately 100 ⁇ 10 4 or less, may be approximately 50 ⁇ 10 4 or less, may be approximately 30 ⁇ 10 4 or less, or may be 28 ⁇ 10 4 or less.
• the Mw of the water-soluble polymer A may be, for example, 0.2 ⁇ 10 4 or more, and is preferably 0.5 ⁇ 10 4 or more.
• the Mw is suitably 0.8 ⁇ 10 4 or more, may be 2 ⁇ 10 4 or more, may be 5 ⁇ 10 4 or more, and may be, for example, 10 ⁇ 10 4 or more.
• the Mw of the water-soluble polymer e.g., water-soluble polymer A or water-soluble polymer B
• a molecular weight calculated from a value based on aqueous gel permeation chromatography (GPC) (aqueous, polyethylene oxide equivalent) can be used.
• GPC gel permeation chromatography
• a model "HLC-8320GPC” manufactured by Tosoh Corporation can be used. The measurement can be performed, for example, under the following conditions. The same method is also used in the examples described later.
• a combination of a water-soluble polymer A having a relatively high Mw and a water-soluble polymer B having a relatively low Mw it is preferable to use a combination of a water-soluble polymer A having a relatively low Mw and a water-soluble polymer B having a relatively high Mw.
• the ratio of the Mw of water-soluble polymer A to the Mw of water-soluble polymer B is greater than 1, and may be 1.5 or more, 3 or more, 5 or more, 7 or more, 10 or more, or 12 or more.
• the ratio of the Mw of water-soluble polymer A to the Mw of water-soluble polymer B may be 400 or less, 100 or less, 50 or less, 30 or less, or 20 or less.
• the ratio of the Mw of the water-soluble polymer A to the Mw of the water-soluble polymer B is less than 1 and may be 0.7 or less.
• the ratio of the Mw of the water-soluble polymer A to the Mw of the water-soluble polymer B may be 0.01 or more, 0.05 or more, or 0.1 or more.
• the content of the water-soluble polymer A relative to the total weight of the polishing composition can be, for example, 1.0 ⁇ 10 ⁇ 7 % by weight or more, and is suitably 1.0 ⁇ 10 ⁇ 6 % by weight or more, and in some preferred embodiments, may be 1.0 ⁇ 10 ⁇ 5 % by weight or more, 5.0 ⁇ 10 ⁇ 5 % by weight or more, 1.0 ⁇ 10 ⁇ 4 % by weight or more, 2.0 ⁇ 10 ⁇ 4 % by weight or more, or 3.0 ⁇ 10 ⁇ 4 % by weight or more.
• the content of the water-soluble polymer A can be, for example, 0.5% by weight or less, and is suitably 0.1% by weight or less, and in some preferred embodiments, may be 0.01% by weight or less, 0.001% by weight or less, or 0.0005% by weight or less.
• the above content refers to the total content of two or more kinds of water-soluble polymer A.
• the content of the water-soluble polymer A can be, for example, 1.0 ⁇ 10 ⁇ 6 % by weight or more, suitably 1.0 ⁇ 10 ⁇ 5 % by weight or more, may be 1.0 ⁇ 10 ⁇ 4 % by weight or more, may be 1.0 ⁇ 10 ⁇ 3 % by weight or more, or may be 5.0 ⁇ 10 ⁇ 3 % by weight or more.
• the content of the water-soluble polymer A can be, for example, 5% by weight or less, suitably 1% by weight or less, preferably 0.5% by weight or less, may be 0.1% by weight or less, or may be 0.05% by weight or less.
• the ratio of the water-soluble polymer A to the water-soluble polymer B described later is not particularly limited.
• the weight ratio (C A /C B ) of the content C A of the water-soluble polymer A to the content C B of the water-soluble polymer B in the polishing composition is not particularly limited as long as the effect of the technology disclosed herein is exhibited.
• the above ratio (C A /C B ) can be, for example, 0.05 or more, and is suitably 0.1 or more, and in some preferred embodiments, it may be 0.25 or more, 0.3 or more, 0.4 or more, 0.5 or more, or 0.55 or more.
• the above ratio (C A /C B ) can be, for example, 5.0 or less, and is suitably 4.0 or less, and in some preferred embodiments, it may be 3.0 or less, 2.0 or less, or 1.0 or less.
• the weight ratio (C A /C S ) of the content C A of the water-soluble polymer A to the content C S of the abrasive grains in the polishing composition is not particularly limited as long as the effect of the technology disclosed herein is exhibited.
• the ratio (C A /C S ) can be, for example, 1.0 ⁇ 10 -5 or more, and is suitably 5.0 ⁇ 10 -5 or more, and in some preferred embodiments, may be 1.0 ⁇ 10 -4 or more, 5.0 ⁇ 10 -4 or more, 1.0 ⁇ 10 -3 or more, 1.2 ⁇ 10 -3 or more, or 1.5 ⁇ 10 -3 or more.
• the ratio (C A /C S ) can be, for example, 0.5 or less, and is suitably 0.1 or less, from the viewpoint of maintaining the polishing rate, and in some preferred embodiments, may be 0.01 or less, 0.007 or less, or 0.005 or less.
• the weight ratio (C A /C T ) of the content C A of the water-soluble polymer A to the content C T of the basic compound in the polishing composition (when two or more basic compounds are included, the total content of them) is not particularly limited as long as the effect of the technology disclosed herein is exhibited.
• the ratio (C A /C T ) can be, for example, 0.001 or more , and is suitably 0.005 or more, and in some preferred embodiments, may be 0.007 or more, may be 0.01 or more, may be 0.012 or more, may be 0.014 or more, or may be 0.016 or more.
• the ratio (C A /C T ) can be, for example, 0.05 or less, and is suitably 0.04 or less, and in some preferred embodiments, may be 0.03 or less, may be 0.02 or less, or may be 0.018 or less (for example, less than 0.018).
• the polishing composition disclosed herein contains a water-soluble polymer B.
• the water-soluble polymer B may be a compound containing a hydroxyl group, a carboxyl group, an acyloxy group, a sulfo group, an amide structure, an imide structure, a quaternary ammonium structure, a heterocyclic structure, a vinyl structure, or the like in the molecule.
• the water-soluble polymer B is a polymer that does not have a cellulose structure in the molecule. Such a water-soluble polymer B tends to improve the dispersion stability of the polishing composition compared to, for example, a cellulose derivative.
• water-soluble polymer B examples include starch derivatives, polymers containing oxyalkylene units, polyvinyl alcohol-based polymers, and polymers containing nitrogen atoms.
• the water-soluble polymer B may be used alone or in combination of two or more types. In this specification, water-soluble polymers that fall under the above-mentioned water-soluble polymer A are not included in the water-soluble polymer B.
• a starch derivative is used as the water-soluble polymer B.
• the starch derivative is a polymer containing an ⁇ -glucose unit as the main repeating unit, and examples thereof include pregelatinized starch, pullulan, carboxymethyl starch, and cyclodextrin.
• One type of starch derivative may be used alone, or two or more types may be used in combination.
• a polymer containing an oxyalkylene unit is used as the water-soluble polymer B.
• the polymer containing an oxyalkylene unit include polyethylene oxide (PEO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO.
• block copolymers of EO and PO or random copolymers of EO and PO are preferred.
• the block copolymer of EO and PO may be a diblock copolymer containing a PEO block and a polypropylene oxide (PPO) block, or a triblock copolymer.
• triblock copolymer examples include PEO-PPO-PEO type triblock copolymers and PPO-PEO-PPO type triblock copolymers. Usually, PEO-PPO-PEO type triblock copolymers are more preferred.
• the molar ratio of EO to PO (EO/PO) constituting the copolymer is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more (e.g., 5 or more), from the viewpoints of solubility in water, washability, etc.
• a polyvinyl alcohol-based polymer is used as the water-soluble polymer B.
• a polyvinyl alcohol-based polymer refers to a polymer containing vinyl alcohol units (hereinafter also referred to as "VA units") as its repeating units.
• VA units vinyl alcohol units
• the polyvinyl alcohol-based polymer may be used alone or in combination of two or more types.
• the polyvinyl alcohol-based polymer may contain only VA units as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units").
• the polyvinyl alcohol-based polymer may be a random copolymer containing VA units and non-VA units, a block copolymer, an alternating copolymer, or a graft copolymer.
• the polyvinyl alcohol-based polymer may contain only one type of non-VA unit, or may contain two or more types of non-VA units.
• the polyvinyl alcohol-based polymer may be unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA).
• Unmodified PVA is a polyvinyl alcohol-based polymer that is produced by hydrolysis (saponification) of polyvinyl acetate and does not substantially contain repeating units other than repeating units (-CH 2 -CH(OCOCH 3 )-) having a structure in which vinyl acetate is vinyl-polymerized and VA units.
• the degree of saponification of the unmodified PVA may be, for example, 60% or more, and from the viewpoint of water solubility, may be 70% or more, 80% or more, or 90% or more. In some embodiments, the degree of saponification of the unmodified PVA may be 98% or more (complete saponification).
• the polyvinyl alcohol-based polymer may be a modified PVA containing a VA unit and a non-VA unit having at least one structure selected from an oxyalkylene group, a carboxy group, a (di)carboxylic acid group, a (di)carboxylic acid ester group, a phenyl group, a naphthyl group, a sulfo group, an amino group, a hydroxyl group, an amide group, an imide group, a nitrile group, an ether group, an ester group, and a salt thereof.
• the non-VA unit that may be contained in the modified PVA may be, for example, a repeating unit derived from an N-vinyl type monomer or an N-(meth)acryloyl type monomer described later, a repeating unit derived from ethylene, a repeating unit derived from an alkyl vinyl ether, a repeating unit derived from a vinyl ester of a monocarboxylic acid having 3 or more carbon atoms, and the like, but is not limited thereto.
• One suitable example of the N-vinyl type monomer is N-vinylpyrrolidone.
• One suitable example of the N-(meth)acryloyl type monomer is N-(meth)acryloylmorpholine.
• the alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether.
• the vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate.
• Suitable examples of the (di)acetone compound include diacetone (meth)acrylamide and acetylacetone.
• an acetalized polyvinyl alcohol polymer is used as the polyvinyl alcohol polymer.
• An example of the acetalized polyvinyl alcohol polymer is modified PVA in which some of the VA units contained in the polyvinyl alcohol polymer are acetalized with an aldehyde.
• the modified PVA in which some of the VA units contained in the polyvinyl alcohol polymer are acetalized with an aldehyde can be obtained by reacting some of the hydroxyl groups of the polyvinyl alcohol polymer with an aldehyde compound or a ketone compound to acetalize the polymer.
• the acetalized polyvinyl alcohol polymer is obtained by an acetalization reaction between a polyvinyl alcohol polymer and an aldehyde compound.
• the aldehyde compound has 1 to 7 carbon atoms, more preferably 2 to 7 carbon atoms.
• aldehyde compounds include, for example, formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde, t-butylaldehyde, and hexylaldehyde; and alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde. These may be used alone or in combination of two or more. In addition, with the exception of formaldehyde, one or more hydrogen atoms may be substituted with a halogen or the like.
• linear or branched alkyl aldehydes are preferred because of their high solubility in water and ease of acetalization reaction, and among these, acetaldehyde, n-propylaldehyde, n-butylaldehyde, and n-pentylaldehyde are more preferred.
• aldehyde compounds having 8 or more carbon atoms such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde, may also be used.
• the acetalized polyvinyl alcohol-based polymer contains a VA unit, which is a structural portion represented by the following chemical formula: -CH 2 -CH(OH)-; and an acetalized structural unit (hereinafter also referred to as a "VAC unit”) represented by the following general formula (2).
• R3 is a hydrogen atom or a linear or branched alkyl group, and the alkyl group may be substituted with a functional group.
• R3 in the above formula (2) is a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms.
• R3 may be one of these groups or a combination of two or more of these groups.
• R3 is preferably a linear or branched alkyl group having 1 to 6 carbon atoms.
• the degree of acetalization of the acetalized polyvinyl alcohol-based polymer can be 1 mol% or more, may be 5 mol% or more, is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more (e.g., 27 mol% or more).
• the degree of acetalization of the acetalized polyvinyl alcohol-based polymer is preferably less than 60 mol%, and is further preferably 50 mol% or less, more preferably 40 mol% or less, and particularly preferably 35 mol% or less (e.g., 33 mol% or less).
• the "degree of acetalization” refers to the proportion of acetalized structural units (VAC units) in all repeating units constituting the acetalized polyvinyl alcohol-based polymer.
• a cation-modified polyvinyl alcohol into which a cationic group such as a quaternary ammonium structure has been introduced may be used.
• the cation-modified polyvinyl alcohol include those into which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, has been introduced.
• the non-VA unit may have a structural portion represented by the chemical formula: -CH 2 -CH(CR 4 (OR 7 )-CR 5 (OR 8 )-R 6 )-.
• R 4 to R 6 each independently represent a hydrogen atom or an organic group
• R 7 and R 8 each independently represent a hydrogen atom or R 9 -CO- (wherein R 9 represents an alkyl group).
• the organic group may be a straight-chain or branched alkyl group having 1 to 8 carbon atoms.
• R 9 in the above formula can be a straight or branched chain alkyl group having from 1 to 8 carbon atoms.
• the modified polyvinyl alcohol polymer is a modified polyvinyl alcohol polymer having a 1,2-diol structure in a side chain, such as a polymer containing non-VA units in which R 4 to R 8 are hydrogen atoms (butenediol-vinyl alcohol copolymer (BVOH)).
• BVOH butenediol-vinyl alcohol copolymer
• the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. Although not particularly limited, in some embodiments, the ratio of the number of moles of the VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units.
• substantially 100% means that the polyvinyl alcohol-based polymer does not contain non-VA units at least intentionally, and typically the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (e.g., less than 1%), including the case of 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.
• the content of VA units in the polyvinyl alcohol-based 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.
• the content of the VA units may be 50% by weight or more (e.g., more than 50% by weight), 70% by weight or more, or 80% by weight or more (e.g., 90% by weight or more, 95% by weight or more, or 98% by weight or more).
• Substantially 100% by weight of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units.
• substantially 100% by weight means that non-VA units are not contained as repeating units constituting the polyvinyl alcohol-based polymer, at least intentionally, and typically means that the content of non-VA units in the polyvinyl alcohol-based polymer is less than 2% by weight (e.g., less than 1% by weight). In some other embodiments, the content of VA units in the polyvinyl alcohol-based polymer may be, for example, 95% by weight or less, 90% by weight or less, 80% by weight or less, or 70% by weight or less.
• a polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit contents within the same molecule.
• a polymer chain refers to a portion (segment) that constitutes part of a single polymer molecule.
• a polyvinyl alcohol-based polymer may contain, within the same molecule, polymer chain A with a VA unit content of more than 50% by weight and polymer chain B with a VA unit content of less than 50% by weight (i.e., a non-VA unit content of more than 50% by weight).
• the polymer chain A may contain only VA units as repeating units, or may contain non-VA units in addition to VA units.
• the content of VA units in the polymer chain A may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of VA units in the polymer chain A may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting the polymer chain A may be VA units.
• the polymer chain B may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units.
• the content of non-VA units in the polymer chain B may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of non-VA units in the polymer chain B may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting the polymer chain B may be non-VA units.
• polyvinyl alcohol-based polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains.
• the above graft copolymers may be graft copolymers having a structure in which polymer chain B (side chain) is grafted to polymer chain A (main chain), or graft copolymers having a structure in which polymer chain A (side chain) is grafted to polymer chain B (main chain).
• a polyvinyl alcohol-based polymer having a structure in which polymer chain B is grafted to polymer chain A can be used.
• polymer chain B examples include polymer chains whose main repeating units are repeating units derived from N-vinyl type monomers; polymer chains whose main repeating units are repeating units derived from N-(meth)acryloyl type monomers; polymer chains whose main repeating units are repeating units derived from vinyl dicarboxylates such as fumaric acid, maleic acid, and maleic anhydride; polymer chains whose main repeating units are repeating units derived from aromatic vinyl monomers such as styrene and vinylnaphthalene; polymer chains whose main repeating units are oxyalkylene units; and the like.
• the term "main repeating unit” refers to a repeating unit that is contained in an amount of more than 50% by weight, unless otherwise specified.
• polymer chain B is a polymer chain having an N-vinyl type monomer as the main repeating unit, 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, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more.
• Substantially all of polymer chain B may be repeating units derived from N-vinyl type monomers.
• examples of N-vinyl type monomers include monomers having a nitrogen-containing heterocycle (e.g., lactam ring) and N-vinyl chain amides.
• Specific examples of N-vinyl lactam type monomers include N-vinyl pyrrolidone, N-vinyl piperidone, N-vinyl morpholinone, N-vinyl caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, and the like.
• Specific examples of N-vinyl chain amides include N-vinyl propionic acid amide, N-vinyl butyric acid amide, and the like.
• Polymer chain B may be, for example, an N-vinyl polymer chain in which more than 50% by weight (e.g., 70% by weight or more, 85% by weight or more, or 95% by weight or more) of its repeating units are N-vinyl pyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinyl pyrrolidone units.
• polymer chain B is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer, i.e., an N-(meth)acryloyl-based polymer chain.
• the content of repeating units derived from N-(meth)acryloyl type monomers in the N-(meth)acryloyl-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more.
• Substantially all of polymer chain B may be repeating units derived from N-(meth)acryloyl type monomers.
• examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group.
• linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; 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
• polymer chain B examples include polymer chains containing oxyalkylene units as the main repeating units, i.e., oxyalkylene-based polymer chains.
• the content of oxyalkylene units in the oxyalkylene-based polymer chains is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more. Substantially all of the repeating units contained in polymer chain B may be oxyalkylene units.
• Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be a repeating unit derived from the corresponding alkylene oxide.
• the oxyalkylene units contained in the oxyalkylene polymer chain may be one type, or two or more types.
• the oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units.
• the oxyalkylene units may be a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer of the corresponding alkylene oxide.
• polymer chain B examples include polymer chains containing repeating units derived from alkyl vinyl ethers (e.g., vinyl ethers having an alkyl group with 1 to 10 carbon atoms), polymer chains containing repeating units derived from monocarboxylic acid vinyl esters (e.g., vinyl esters of monocarboxylic acids with 3 or more carbon atoms), and polymer chains into which cationic groups (e.g., cationic groups having a quaternary ammonium structure) have been introduced.
• alkyl vinyl ethers e.g., vinyl ethers having an alkyl group with 1 to 10 carbon atoms
• monocarboxylic acid vinyl esters e.g., vinyl esters of monocarboxylic acids with 3 or more carbon atoms
• cationic groups e.g., cationic groups having a quaternary ammonium structure
• the polyvinyl alcohol-based polymer as the water-soluble polymer B in the technology disclosed herein is preferably a modified polyvinyl alcohol, which is a copolymer containing VA units and non-VA units.
• the degree of saponification of the modified polyvinyl alcohol is usually 50 mol% or more, preferably 65 mol% or more, more preferably 70 mol% or more, for example 75 mol% or more.
• a polymer containing nitrogen atoms is used as the water-soluble polymer B.
• a polishing composition containing a polymer containing nitrogen atoms improves the ability to eliminate HLM bumps and tends to produce a high-quality polished surface.
• Non-limiting examples of polymers containing nitrogen atoms include polymers containing N-vinyl type monomer units; polymers containing N-(meth)acryloyl type monomer units; and the like.
• the polymers containing nitrogen atoms may be used alone or in combination of two or more types.
• an N-vinyl type polymer (excluding water-soluble polymer A) may be used as water-soluble polymer B (polymer containing nitrogen atoms).
• Examples of N-vinyl type polymers include polymers containing repeating units derived from monomers having a nitrogen-containing heterocycle (e.g., lactam ring).
• polymers examples include homopolymers and copolymers of N-vinyl lactam type monomers (e.g., copolymers in which the copolymerization ratio of N-vinyl lactam type monomers exceeds 50% by weight), homopolymers and copolymers of N-vinyl linear amides (e.g., copolymers in which the copolymerization ratio of N-vinyl linear amides exceeds 50% by weight), and the like.
• N-vinyl lactam type monomers e.g., copolymers in which the copolymerization ratio of N-vinyl lactam type monomers exceeds 50% by weight
• N-vinyl linear amides e.g., copolymers in which the copolymerization ratio of N-vinyl linear amides exceeds 50% by weight
• N-vinyl lactam type monomers i.e., compounds having a lactam structure and an N-vinyl group in one molecule
• N-vinylpyrrolidone VP
• N-vinylpiperidone N-vinylmorpholinone
• N-vinylcaprolactam VC
• N-vinyl-1,3-oxazin-2-one N-vinyl-3,5-morpholinedione.
• polymers containing N-vinyl lactam type monomer units include polyvinylpyrrolidone (PVP), polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), block copolymers, alternating copolymers, and graft copolymers containing polymer chains containing one or both of VP and VC.
• N-vinyl chain amides include N-vinylpropionamide and N-vinylbutyric acid amide. From the viewpoint of improving the ability to eliminate HLM protuberances, N-vinyl lactam type polymers are particularly preferably used as the water-soluble polymer B disclosed herein. Of these, PVP is particularly preferably used.
• an N-(meth)acryloyl type polymer may be preferably used as the water-soluble polymer B.
• N-(meth)acryloyl type polymers include homopolymers and copolymers of N-(meth)acryloyl type monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl type monomers exceeds 50% by weight).
• Examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group.
• chain amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, and 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.
• N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide
• polymers containing chain amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by weight).
• 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.
• An example of a polymer containing a cyclic amide having an N-(meth)acryloyl group as a monomer unit is an acryloylmorpholine-based polymer (PACMO).
• Typical examples of acryloylmorpholine-based 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).
• ACMO N-acryloylmorpholine
• ACMO copolymers of ACMO
• the water-soluble polymer B is a polymer that does not have a tertiary amine structure.
• the effects of the present invention can be preferably exhibited.
• the water-soluble polymer B is a polymer containing a tertiary amide group.
• the weight average molecular weight (Mw) of the water-soluble polymer B is not particularly limited.
• the Mw of the water-soluble polymer B may be, for example, about 200 ⁇ 10 4 or less, and is suitably about 150 ⁇ 10 4 or less. From the viewpoint of cleaning properties, etc., it is preferably about 100 ⁇ 10 4 or less, and may be about 50 ⁇ 10 4 or less, for example, 10 ⁇ 10 4 or less, 8 ⁇ 10 4 or less, 5 ⁇ 10 4 or less, 3 ⁇ 10 4 or less, or 2 ⁇ 10 4 or less.
• the Mw of the water-soluble polymer B may be, for example, 0.2 ⁇ 10 4 or more, and is preferably 0.5 ⁇ 10 4 or more.
• the Mw is suitably 0.8 ⁇ 10 4 or more, and may be 1.0 ⁇ 10 4 or more, or may be 1.5 ⁇ 10 4 or more.
• the preferred molecular weight range of the water-soluble polymer B may vary depending on the type of polymer used.
• the Mw of the N-vinyl lactam type polymer preferably PVP
• the Mw may be 30 ⁇ 10 4 or less, preferably 20 ⁇ 10 4 or less, for example, 10 ⁇ 10 4 or less, 8 ⁇ 10 4 or less, 5 ⁇ 10 4 or less, 3 ⁇ 10 4 or less, or 2 ⁇ 10 4 or less.
• the Mw may be, for example, 0.2 ⁇ 10 4 or more, usually 0.5 ⁇ 10 4 or more, 0.8 ⁇ 10 4 or more, 1.0 ⁇ 10 4 or more, or 1.5 ⁇ 10 4 or more.
• a nonionic polymer can be preferably used as the water-soluble polymer B.
• a nonionic polymer electrostatic adsorption between the abrasive grains (typically silica particles) and the water-soluble polymer can be suppressed, and gelation of the composition can be suppressed.
• the content of the water-soluble polymer B relative to the total weight of the polishing composition can be, for example, 1.0 ⁇ 10 ⁇ 7 % by weight or more, and is suitably 1.0 ⁇ 10 ⁇ 6 % by weight or more, and in some preferred embodiments, may be 1.0 ⁇ 10 ⁇ 5 % by weight or more, 5.0 ⁇ 10 ⁇ 5 % by weight or more, 1.0 ⁇ 10 ⁇ 4 % by weight or more, 2.0 ⁇ 10 ⁇ 4 % by weight or more, or 3.0 ⁇ 10 ⁇ 4 % by weight or more.
• the content of the water-soluble polymer B can be, for example, 0.5% by weight or less, and is suitably 0.1% by weight or less, from the viewpoint of maintaining the polishing rate, and in some preferred embodiments, may be 0.01% by weight or less, 0.005% by weight or less, or 0.001% by weight or less.
• These contents can be preferably applied to the contents in the polishing liquid (working slurry) supplied to the object to be polished, for example.
• the content of the water-soluble polymer B (when two or more kinds of water-soluble polymer B are contained, the total content thereof) can be, for example, 1.0 ⁇ 10 ⁇ 6 % by weight or more, suitably 1.0 ⁇ 10 ⁇ 5 % by weight or more, may be 1.0 ⁇ 10 ⁇ 4 % by weight or more, may be 1.0 ⁇ 10 ⁇ 3 % by weight or more, or may be 5.0 ⁇ 10 ⁇ 3 % by weight or more.
• the content of the water-soluble polymer B can be, for example, 5% by weight or less, suitably 1% by weight or less, preferably 0.5% by weight or less, may be 0.1% by weight or less, or may be 0.05% by weight or less.
• the weight ratio (C B /C S ) of the content C B of the water-soluble polymer B to the content C S of the abrasive grains in the polishing composition is not particularly limited as long as the effects of the technology disclosed herein are exhibited.
• the ratio (C B /C S ) can be, for example, 1.0 ⁇ 10 -6 or more, and is suitably 1.0 ⁇ 10 -5 or more, and in some preferred embodiments, may be 1.0 ⁇ 10 -4 or more, may be 5.0 ⁇ 10 -4 or more, may be 1.0 ⁇ 10 -3 or more, or may be 2.0 ⁇ 10 -3 or more.
• the ratio (C B /C S ) can be, for example, 0.5 or less, and is suitably 0.2 or less, and in some preferred embodiments, may be 0.1 or less, 0.01 or less, or 0.005 or less.
• the total amount of water-soluble polymers relative to the total weight of the polishing composition can be, for example, 1.0 ⁇ 10 ⁇ 6 % by weight or more, and is suitably 1.0 ⁇ 10 ⁇ 5 % by weight or more, and in some preferred embodiments, may be 5.0 ⁇ 10 ⁇ 5 % by weight or more, 7.0 ⁇ 10 ⁇ 5 % by weight or more, 1.0 ⁇ 10 ⁇ 4 % by weight or more, 5.0 ⁇ 10 ⁇ 4 % by weight or more, or 1.0 ⁇ 10 ⁇ 3 % by weight or more.
• the total amount of the water-soluble polymers can be, for example, 0.5% by weight or less, and is suitably 0.1% by weight or less, and in some preferred embodiments, may be 0.01% by weight or less, 0.005% by weight or less, or 0.002% by weight or less.
• These contents can be preferably applied to the contents in the polishing liquid (working slurry) supplied to the polishing object, for example.
• the total amount of the water-soluble polymers can be, for example, 1.0 ⁇ 10 ⁇ 6 % by weight or more, suitably 1.0 ⁇ 10 ⁇ 5 % by weight or more, may be 1.0 ⁇ 10 ⁇ 4 % by weight or more, may be 1.0 ⁇ 10 ⁇ 3 % by weight or more, or may be 5.0 ⁇ 10 ⁇ 3 % by weight or more.
• the total amount of the water-soluble polymers can be, for example, 5% by weight or less, suitably 1% by weight or less, preferably 0.5% by weight or less, may be 0.1% by weight or less, or may be 0.05% by weight or less.
• the weight ratio (C AB /C S ) of the total amount of water-soluble polymers C AB (total content of two or more water-soluble polymers) to the content C S of abrasive grains in the polishing composition is not particularly limited as long as the effects of the technology disclosed herein are exhibited.
• the ratio (C AB /C S ) can be, for example, 1.0 ⁇ 10 ⁇ 6 or more, and is suitably 1.0 ⁇ 10 ⁇ 5 or more, and in some preferred embodiments, may be 1.0 ⁇ 10 ⁇ 4 or more, may be 5.0 ⁇ 10 ⁇ 4 or more, may be 1.0 ⁇ 10 ⁇ 3 or more, or may be 2.0 ⁇ 10 ⁇ 3 or more.
• the ratio (C AB /C S ) can be, for example, 0.5 or less, and is suitably 0.2 or less, and in some preferred embodiments, may be 0.1 or less, 0.05 or less, or 0.01 or less.
• the polishing composition disclosed herein contains water.
• water ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc. can be preferably used.
• the water used preferably has a total transition metal ion content of, for example, 100 ppb or less.
• the purity of water can be increased by removing impurity ions with an ion exchange resin, removing foreign matter with a filter, distillation, etc.
• the polishing composition disclosed herein may further contain an organic solvent (such as a lower alcohol or a lower ketone) that can be uniformly mixed with water, if necessary.
• the solvent contained in the polishing composition is preferably 90% by volume or more of water, and more preferably 95% by volume or more (e.g., 99 to 100% by volume) of water.
• the polishing composition disclosed herein may contain a chelating agent.
• a chelating agent By including a chelating agent in the polishing composition, metal contamination of the polished surface after preliminary polishing can be suppressed.
• the chelating agent may be used alone or in combination of two or more. Examples of the chelating agent include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents.
• aminocarboxylic acid chelating agent examples include alanine, glycine, ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate.
• organic phosphonic acid chelating agents include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, phosphonobutanetricarboxylic acid (PBTC), nitrilotris(methylenephosphonic acid) (NTMP), and ⁇ -methylphosphonosuccinic acid.
• PBTC 2-phosphonobutane-1,2-dicarboxylic acid
• Particularly preferred chelating agents include triethylenetetraminehexaacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetrakis(methylenephosphonic acid) and diethylenetriaminepenta(methylenephosphonic acid).
• the content of the chelating agent relative to the total weight of the polishing composition is suitably, for example, 1.0 ⁇ 10 ⁇ 5 % by weight or more, and in some preferred embodiments, may be 1.0 ⁇ 10 ⁇ 4 % by weight or more, 5.0 ⁇ 10 ⁇ 4 % by weight or more, or 1.0 ⁇ 10 ⁇ 3 % by weight or more.
• the content of the chelating agent can be, for example, 0.5% by weight or less, and is suitably 0.1% by weight or less, and in some preferred embodiments, may be 0.01% by weight or less, or may be 0.005% by weight or less.
• the polishing composition disclosed herein may further contain, as necessary, known additives that can be used in polishing compositions (e.g., polishing compositions used in the polishing process of silicon wafers), such as inorganic acid salts, organic acid salts, surfactants, preservatives, and fungicides, within the range that does not significantly impair the effects of the present invention.
• known additives that can be used in polishing compositions (e.g., polishing compositions used in the polishing process of silicon wafers), such as inorganic acid salts, organic acid salts, surfactants, preservatives, and fungicides, within the range that does not significantly impair the effects of the present invention.
• examples of inorganic acid salts include salts of hydrohalic acids (e.g., hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid), nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfite, thiosulfuric acid, silicic acid, boric acid, phosphoric acid, and the like.
• hydrohalic acids e.g., hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid
• nitric acid e.g., sulfuric acid, sulfurous acid, hydrogen sulfite, thiosulfuric acid, silicic acid, boric acid, phosphoric acid, and the like.
• organic acid salts include salts of carboxylic acids (e.g., formic acid, acetic acid, propionic acid, benzoic acid, butyric acid, citric acid, tartaric acid, trifluoroacetic acid), organic sulfonic acids (e.g., methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid), sulfamic acid, and organic phosphoric acids (e.g., ethyl phosphoric acid).
• carboxylic acids e.g., formic acid, acetic acid, propionic acid, benzoic acid, butyric acid, citric acid, tartaric acid, trifluoroacetic acid
• organic sulfonic acids e.g., methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid
• the cations constituting the inorganic acid salts and organic acid salts are not particularly limited, and examples thereof include alkali metals (lithium, sodium, potassium, and the like), alkaline earth metals (calcium, strontium, barium, and the like), magnesium, ammonium, and the like.
• specific examples of salts of sulfuric acid (sulfates) include lithium sulfate, sodium sulfate, potassium sulfate, and ammonium sulfate. Polishing using sulfates tends to effectively exhibit the effect of eliminating bumps.
• the inorganic acid salts and organic acid salts do not include the basic compounds.
• the organic acid salts do not include the chelating agents.
• the surfactant may be used alone or in combination of two or more.
• examples of the surfactant are not particularly limited, and include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants.
• the dispersion stability of the polishing composition can be improved by using a surfactant (e.g., a water-soluble organic compound with a molecular weight of less than 0.2 ⁇ 10 4 ).
• the Mw of the surfactant can be determined by GPC (water-based, polyethylene glycol equivalent) or calculated from a chemical formula.
• the polishing composition has a composition in which the amount of surfactant used is limited.
• the content of surfactant in the polishing composition (e.g., polishing liquid) may be less than 0.3 wt.%, less than 0.2 wt.%, less than 0.1 wt.%, less than 0.03 wt.%, or less than 0.01 wt.%.
• the technology disclosed herein may be preferably practiced in an embodiment in which the polishing composition is substantially free of surfactant, i.e., at least intentionally does not contain surfactant.
• preservatives and antifungal agents examples include isothiazolinone compounds, paraoxybenzoic acid esters, phenoxyethanol, etc.
• the polishing composition disclosed herein is preferably substantially free of an oxidizing agent. If an oxidizing agent is contained in the polishing composition, the substrate surface (e.g., the surface of a silicon wafer) may be oxidized by the supply of the composition, resulting in the formation of an oxide film, which may result in a decrease in the polishing rate.
• the polishing composition being substantially free of an oxidizing agent means that an oxidizing agent is not intentionally blended, at least, and it is acceptable that a trace amount of an oxidizing agent is inevitably contained due to the raw materials, manufacturing method, etc.
• the above-mentioned trace amount means that the molar concentration of the oxidizing agent in the polishing composition is 0.001 mol/L or less (preferably 0.0005 mol/L or less, more preferably 0.0001 mol/L or less, even more preferably 0.00005 mol/L or less, and particularly preferably 0.00001 mol/L or less).
• the polishing composition does not contain an oxidizing agent.
• the polishing composition disclosed herein may be preferably implemented in an embodiment that does not contain any of hydrogen peroxide, sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate, for example.
• the polishing composition disclosed herein is supplied to an object to be polished in the form of a polishing liquid (working slurry) containing the polishing composition, for example, and used to polish the object to be polished.
• the polishing liquid may be prepared, for example, by diluting (e.g., diluting with water) a concentrated solution of any of the polishing compositions disclosed herein.
• the polishing composition may be used as it is as a polishing liquid.
• the concentration ratio of the concentrated solution may be, for example, about 2 to 140 times on a volume basis, and is usually about 5 to 80 times.
• the pH of the polishing composition is, for example, 8.0 or more, preferably 8.5 or more, more preferably 9.0 or more, even more preferably 9.5 or more, and may be 10.0 or more (for example, 10.5 or more). As the pH increases, the polishing rate tends to improve. On the other hand, from the viewpoint of preventing dissolution of the abrasive grains (for example, silica particles) and suppressing a decrease in the mechanical polishing action of the abrasive grains, the pH of the polishing composition is usually appropriately 12.0 or less, preferably 11.8 or less, and more preferably 11.5 or less.
• the pH of the polishing composition can be determined by using a pH meter (for example, a glass electrode type hydrogen ion concentration indicator (model number F-23) manufactured by Horiba, Ltd.) and performing three-point calibration using standard buffer solutions (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)), then placing the glass electrode in the polishing composition and measuring the value after it has stabilized for at least two minutes.
• a pH meter for example, a glass electrode type hydrogen ion concentration indicator (model number F-23) manufactured by Horiba, Ltd.
• the polishing composition disclosed herein may be a one-component type or a multi-component type, including a two-component type.
• the polishing liquid may be prepared by mixing at least part A, which contains abrasive grains, with part B, which contains the remaining components, and diluting the mixture at an appropriate time as necessary.
• the method for producing the polishing composition disclosed herein is not particularly limited.
• the components contained in the polishing composition may be mixed using a well-known mixing device such as a blade stirrer, ultrasonic disperser, or homomixer.
• the manner in which these components are mixed is not particularly limited, and for example, all the components may be mixed at once, or may be mixed in an appropriately set order.
• the polishing composition disclosed herein can be used for polishing an object to be polished, for example, in an embodiment including the following operations. That is, a working slurry containing any of the polishing compositions disclosed herein is prepared. Then, the polishing composition is supplied to an object to be polished, and polished by a conventional method.
• the object to be polished is set in a general polishing device, and the polishing composition is supplied to the surface (surface to be polished) of the object to be polished through the polishing pad of the polishing device.
• the polishing pad is pressed against the surface of the object to be polished, and the two are moved relatively (for example, rotated). Through this polishing process, the polishing of the object to be polished is completed.
• the polishing pad used in the polishing process is not particularly limited.
• any of the following types may be used: polyurethane foam type, nonwoven fabric type, suede type, abrasive type, non-abrasive type, etc.
• the polishing device may be a double-sided polishing device that polishes both sides of the object to be polished simultaneously, or a single-sided polishing device that polishes only one side of the object to be polished.
• the polishing composition may be used in a manner that disposes of the composition once it has been used for polishing (so-called "run-through"), or may be recycled and reused.
• One example of a method for recycling a polishing composition is to collect the used polishing composition discharged from a polishing device in a tank and then supply the collected polishing composition to the polishing device again.
• the polishing composition disclosed herein is not particularly limited, but can be preferably used for preliminary polishing of a surface made of a silicon material.
• the silicon material preferably contains at least one material selected from the group consisting of silicon single crystal, amorphous silicon, and polysilicon.
• the polishing composition is particularly suitable for polishing a surface made of silicon single crystal (e.g., silicon wafer).
• the polishing composition is excellent in the performance of eliminating the protuberance of the HLM peripheral portion (protuberance eliminating ability), and can be preferably applied to polishing a surface to be polished including a surface to which an HLM is attached.
• the polishing composition disclosed herein can be particularly preferably used in a preliminary polishing step, more specifically, in a rough polishing step (primary polishing step) which is the first polishing step in a polishing step, and in an intermediate polishing step (secondary polishing step) which follows the rough polishing step. Since a higher polishing rate may be required in the preliminary polishing step, it is meaningful to use the polishing composition disclosed herein in the preliminary polishing step to maintain the polishing rate and eliminate the protuberance of the HLM peripheral portion at the same time.
• the silicon wafer may be subjected to a general treatment that can be applied to silicon wafers, such as lapping, etching, or application of the above-mentioned HLM, prior to the polishing step using the polishing composition disclosed herein.
• the silicon wafer has a surface made of silicon, for example.
• Such a silicon wafer is preferably a silicon single crystal wafer, for example, a silicon single crystal wafer obtained by slicing a silicon single crystal ingot.
• the polishing composition disclosed herein is suitable for polishing a silicon single crystal wafer with an HLM.
• the polishing composition disclosed herein can be suitably used for polishing an object that does not have an HLM.
• the matters disclosed in this specification include the following.
• Abrasive grains, a basic compound, a water-soluble polymer A, a water-soluble polymer B, and water The water-soluble polymer A is represented by the following general formula (1): (wherein R 1 is a hydrocarbon group having 5 or less carbon atoms, and R 2 is a hydrogen atom or a hydrocarbon group having 3 or less carbon atoms); A polishing composition, wherein the water-soluble polymer B is a polymer having no cellulose structure in the molecule.
• polishing composition according to any one of [1] to [7] above which is used for pre-polishing a surface made of a silicon material.
• a polishing method comprising polishing a surface of a silicon material with the polishing composition according to any one of [1] to [9] above.
• Example 1 A concentrated solution of a polishing composition was prepared by mixing colloidal silica (average primary particle size: 55 nm) as an abrasive, tetramethylammonium hydroxide (TMAH) and potassium carbonate ( K2CO3 ) as basic compounds, poly-N-vinylacetamide (PNVA ) with a Mw of 27 x 104 and polyvinylpyrrolidone (PVP) with a Mw of 2 x 104 as water-soluble polymers, ethylenediaminetetrakis(methylenephosphonic acid) (EDTPO) as a chelating agent, and ion-exchanged water.
• colloidal silica average primary particle size: 55 nm
• TMAH tetramethylammonium hydroxide
• K2CO3 potassium carbonate
• PNVA poly-N-vinylacetamide
• PVP polyvinylpyrrolidone
• EDTPO ethylenediaminetetrakis(methylenephosphonic
• the obtained concentrated solution of the polishing composition was diluted 50 times by volume with ion-exchanged water to obtain a polishing composition containing 0.3 wt% abrasive grains, 0.05 wt% basic compound (0.03 wt% TMAH, 0.02 wt % K2CO3 ), 0.0005 wt% PNVA, 0.0009 wt% PVP, and 0.0008 wt% chelating agent.
• Example 2 to 3 and Comparative Examples 1 to 3 Polishing compositions according to each example were prepared in the same manner as in Example 1, except that the type, Mw and content of the water-soluble polymer were changed as shown in Table 1.
• PNVA poly-N-vinylacetamide
• Comparative Example 2 a graft copolymer (hereinafter referred to as "PVA-g-PVP") with an Mw of 6 ⁇ 10 4 , in which polyvinyl alcohol (PVA) with a saponification degree of 95% or more is used as the main chain and polyvinylpyrrolidone (PVP) is used as the side chain, was used.
• PVA-g-PVP graft copolymer with an Mw of 6 ⁇ 10 4 , in which polyvinyl alcohol (PVA) with a saponification degree of 95% or more is used as the main chain and polyvinylpyrrolidone (PVP) is used as the side chain, was used.
• PVA-g-PVP polyviny
• ⁇ Performance evaluation> (Polishing silicon wafers)
• the polishing composition according to each example was used as a polishing liquid (working slurry) to polish the surface of the object to be polished (test piece) under the following conditions.
• As the test piece a commercially available silicon single crystal wafer (thickness: 545 ⁇ m, conductivity type: P type, crystal orientation: ⁇ 100>, resistivity: 1 ⁇ cm or more and less than 100 ⁇ cm) with a diameter of 100 mm that had been lapped and etched was used.
• the wafer was provided with an HLM.
• Polishing device Single-sided polishing device manufactured by Engis Japan, model number "EJ-380IN” Polishing pressure: 12 kPa Platen rotation speed: +50 rpm (counterclockwise is positive (+). The same applies below.) Head rotation speed: +40 rpm Polishing pad: Nitta DuPont, product name "SUBA800” Polishing liquid supply rate: 100 mL/min (flowing) Polishing environment temperature: 25°C Polishing time: 20 minutes
• the surface shape of the HLM periphery of the silicon wafer before and after polishing was measured using a stylus surface roughness shape measuring instrument (SURFCOM 1500DX, manufactured by Tokyo Seimitsu Co., Ltd.). Specifically, the needle of the measuring instrument was brought into contact with the surface of the substrate and run along the HLM periphery to measure the portion where no protuberance was generated (reference surface) and the height of the protuberance.
• SURFCOM 1500DX manufactured by Tokyo Seimitsu Co., Ltd.
• Hpre height from the reference surface to the highest point of the protuberance before polishing
• Hpost height from the reference surface to the highest point of the protuberance after polishing
• polishing compositions of Examples 1 to 3 which contain abrasive grains, a basic compound, and water and use PNVA and PVP in combination as water-soluble polymers, have improved relative HLM protuberance elimination properties compared to Comparative Example 1, which uses only PVP alone as the water-soluble polymer.
• the polishing composition of Comparative Example 2 which uses PVA-g-PVP as the water-soluble polymer in combination with PVP, did not show any particular improvement in HLM protuberance elimination properties. It was also confirmed that the polishing composition of Comparative Example 3, which does not use a water-soluble polymer, has inferior HLM protuberance elimination properties.

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