Methods for preparing abrasive particles, compositions for chemical mechanical grinding, and chemical mechanical grinding methods.

Abstract

This invention provides abrasive grains or a chemical mechanical polishing composition for selectively polishing silicon nitride films not only relative to silicon oxide films but also relative to amorphous silicon films or polycrystalline silicon films, a method for manufacturing the abrasive grains, and a chemical mechanical polishing method. The method for manufacturing the abrasive grains of this invention includes: a first step of heating a mixture containing particles with hydrogen sulfide groups (-SH) covalently fixed to the surface and a compound having carbon-carbon unsaturated double bonds; and a second step, after the first step, further adding a peroxide and heating.

Description

Technical Field

[0001] This invention relates to a method for manufacturing abrasive particles, a composition for chemical mechanical polishing, and a chemical mechanical polishing method. Background Technology

[0002] The miniaturization of wiring layers, including wiring and plugs, formed within semiconductor devices is underway. Accompanying this is a method of planarizing the wiring layers using chemical mechanical polishing (CMP). Generally, in CMP polishing of silicon oxide (SiO2) films, silicon nitride (SiN) films are used as barrier films to detect endpoints, taking advantage of the fact that SiN films are difficult to polish. After removing the silicon oxide film by CMP, the silicon nitride film, which serves as the barrier film, also needs to be removed.

[0003] In order to selectively remove silicon nitride films by CMP, it is necessary to increase the polishing speed ratio (hereinafter also referred to as "selectivity ratio") of the silicon nitride film relative to the silicon oxide film or polycrystalline silicon film. To achieve this characteristic, methods have been proposed for polishing silicon nitride films using polishing slurries containing phosphoric acid, nitric acid, or hydrofluoric acid with the pH adjusted to 1 to 5, or polishing slurries containing acidic additives that inhibit etching and can selectively polish silicon nitride films (see Patent Documents 1 to 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-214667

[0007] Patent Document 2: Japanese Patent Application Publication No. 2006-120728 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, while the polishing slurries described in Patent Documents 1 and 2 can selectively polish silicon nitride films relative to silicon oxide films, it is unclear whether they can also selectively polish silicon nitride films relative to amorphous silicon films or polycrystalline silicon films. If silicon nitride films can be selectively polished not only relative to silicon oxide films but also relative to amorphous silicon films and polycrystalline silicon films, then in CMP (Continuous Polishing) of silicon nitride films, silicon oxide films, amorphous silicon films, and polycrystalline silicon films can all be used as barrier films, thus greatly improving convenience.

[0010] Thus, an abrasive or chemical mechanical polishing composition is sought for selectively polishing silicon nitride films not only relative to silicon oxide films but also relative to amorphous silicon films or polycrystalline silicon films.

[0011] Technical means to solve the problem

[0012] An embodiment of the method for manufacturing abrasive particles of the present invention includes:

[0013] The first step involves heating a mixture containing particles with hydrogen sulfide (-SH) groups covalently fixed to the surface and compounds having carbon-carbon unsaturated double bonds; and

[0014] The second step, following the first step, involves adding peroxide and heating.

[0015] In one embodiment of the method for manufacturing the abrasive particles,

[0016] The mixture in the first step may also contain a free radical generating agent.

[0017] In any embodiment of the method for manufacturing the abrasive particles,

[0018] The compound having carbon-carbon unsaturated double bonds may have an average molecular weight of 100 to 10,000.

[0019] In any embodiment of the method for manufacturing the abrasive particles,

[0020] The abrasive grains may have functional groups represented by the following general formula (1) on their surface.

[0021] -SO3 - M + ·····(1)

[0022] (M + (representing a monovalent cation)

[0023] In any embodiment of the method for manufacturing the abrasive particles,

[0024] In a chemical mechanical polishing composition containing the abrasive particles, the side potential of the abrasive particles may be less than -10mV.

[0025] An embodiment of the chemical mechanical grinding composition of the present invention comprises:

[0026] Abrasive particles, manufactured by the method of any of the embodiments described above; and

[0027] Liquid medium.

[0028] An embodiment of the chemical mechanical grinding composition of the present invention,

[0029] This is a chemical mechanical polishing composition containing abrasive particles and a liquid medium, wherein,

[0030] Polymer chains are covalently grafted onto the surface of the abrasive particles.

[0031] The abrasive grains have functional groups represented by the following general formula (1) on their surface.

[0032] -SO3 - M + ·····(1)

[0033] (M+ represents a monovalent cation)

[0034] An embodiment of the chemical mechanical grinding composition of the present invention,

[0035] This is a chemical mechanical polishing composition containing abrasive particles and a liquid medium, wherein,

[0036] Polymer chains via -SO x -(x is an integer from 0 to 2) and is grafted onto the surface of the abrasive grains via covalent bonds.

[0037] The chemical mechanical grinding composition of any of the embodiments described above

[0038] This can be a composition used for grinding positively charged materials among a variety of materials constituting semiconductor devices during chemical mechanical polishing.

[0039] In any embodiment of the chemical mechanical grinding composition,

[0040] The positively charged material can be a silicon nitride film.

[0041] An embodiment of the chemical mechanical polishing method of the present invention includes:

[0042] The step of using the chemical mechanical polishing composition of any of the embodiments described above to polish a material that is positively charged during chemical mechanical polishing among a variety of materials constituting a semiconductor device.

[0043] The effects of the invention

[0044] According to the method for manufacturing abrasive grains of the present invention, abrasive grains for selectively abrading silicon nitride films not only relative to silicon oxide films but also relative to amorphous silicon films or polycrystalline silicon films can be manufactured. Furthermore, according to the chemical mechanical polishing composition of the present invention, silicon nitride films can also be selectively abraded not only relative to silicon oxide films but also relative to amorphous silicon films or polycrystalline silicon films. Attached Figure Description

[0045] Figure 1 It is a cross-sectional view schematically showing the manufacturing steps of the processed object with components separated from each other.

[0046] Figure 2It is a schematic cross-sectional view of the workpiece after the first grinding step.

[0047] Figure 3 It is a schematic cross-sectional view of the workpiece after the second grinding step.

[0048] Figure 4 It is a schematic three-dimensional diagram representing a chemical mechanical grinding apparatus.

[0049] [Explanation of Symbols]

[0050] 10: Silicon wafers

[0051] 12: Thermal Oxidation Film

[0052] 14: Silicon nitride film

[0053] 16: Slot

[0054] 18: Silicon oxide film

[0055] 42: Slurry supply nozzle

[0056] 44: Chemical mechanical grinding compositions (slurries)

[0057] 46: Abrasive cloth

[0058] 48: Turntable

[0059] 50: Semiconductor substrate

[0060] 52: Bearing head

[0061] 54: Water supply nozzle

[0062] 56: Dresser

[0063] 100: The processed object

[0064] 200: Chemical Mechanical Grinding Apparatus Detailed Implementation

[0065] The preferred embodiments of the present invention will now be described in detail. Furthermore, the present invention is not limited to the embodiments described below, and includes various modifications implemented without altering the spirit of the invention.

[0066] In this specification, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid". Similarly, "(meth)acrylamide" refers to both "acrylamide" and "methacrylamide".

[0067] In this specification, the numerical range described using "X~Y" is interpreted as including the value X as the lower limit and the value Y as the upper limit.

[0068] 1. Method for manufacturing abrasive particles

[0069] A method for manufacturing abrasive grains according to one embodiment of the present invention includes a first step of heating a mixture containing particles with hydrogen sulfide (-SH) groups covalently fixed to the surface and a compound having carbon-carbon unsaturated double bonds; and a second step of adding a peroxide and heating the mixture after the first step. According to the method for manufacturing abrasive grains of this embodiment, abrasive grains can be manufactured for selectively abrading silicon nitride films not only relative to silicon oxide films but also relative to amorphous silicon films or polycrystalline silicon films. Hereinafter, the method for manufacturing abrasive grains of this embodiment will be described in detail step by step.

[0070] 1.1. First Step

[0071] The first step is to heat a mixture containing particles with hydrogen sulfide (-SH) groups covalently fixed to the surface and a compound having carbon-carbon unsaturated double bonds. By performing this first step, particles can be produced in which polymers are covalently linked to the particle surface via -S- groups.

[0072] In the first step, hydrogen sulfide (-SH) groups are covalently fixed to the surface of the particles. These covalently fixed hydrogen sulfide (-SH) groups do not include particles with compounds containing hydrogen sulfide groups that are physically or ionicly adsorbed on the surface.

[0073] The material of the particles used as abrasive grains is not particularly limited, and inorganic oxides such as silicon oxide, cerium dioxide, aluminum oxide, zirconium oxide, and titanium dioxide can be included, with silicon oxide being preferred. Examples of silicon oxide include fumed silicon oxide and colloidal silicon oxide, but from the viewpoint of reducing grinding defects such as scratches, colloidal silicon oxide is preferred. Colloidal silicon oxide can be, for example, colloidal silicon oxide manufactured by the method described in Japanese Patent Application Publication No. 2003-109921.

[0074] As a method for fixing hydrogen sulfide (-SH) groups to the surface of silica particles via covalent bonds, the methods described in Japanese Patent Application Publication No. 2010-269985 or in the "Journal of Industrial and Engineering Chemistry (J. Ind. Eng. Chem.)," Vol. 12, No. 6, (2006) 911-917, etc., can be applied. For example, by thoroughly stirring silica particles and a thiol-containing silane coupling agent in an acidic medium, the thiol-containing silane coupling agent can be covalently bonded to the surface of the silica particles. Examples of thiol-containing silane coupling agents include (3-mercaptopropyl)methyldimethoxysilane and (3-mercaptopropyl)trimethoxysilane.

[0075] In the first step, a compound having carbon-carbon unsaturated double bonds is used. There are no particular limitations on the compound having carbon-carbon unsaturated double bonds, as long as it can react with the hydrogen sulfide group (-SH) fixed on the particle surface via an ene-thiol reaction and bond to the particle surface via a -S-bond. For example, by reacting a polymer having reactive carbon-carbon unsaturated double bonds, polymer chains can be easily grafted onto the particle surface via -S-bonds. Alternatively, by reacting a monomer having carbon-carbon unsaturated double bonds, polymer synthesis and polymer chain grafting onto the particle surface can be carried out simultaneously, with polymer chains grafted onto the particle surface via -S-bonds.

[0076] As the polymer having the reactive carbon-carbon unsaturated double bond, a polyoxyalkylene group having a reactive carbon-carbon unsaturated double bond is preferably used. Examples of polyoxyalkylene groups having a reactive carbon-carbon unsaturated double bond include compounds that undergo alkylene oxide addition to allyl alcohol, as well as compounds whose ends are blocked by aliphatic compounds. Examples include compounds that undergo ethylene oxide addition to allyl alcohol, compounds that undergo propylene oxide addition to allyl alcohol, compounds that undergo random addition of ethylene oxide and propylene oxide to allyl alcohol, and compounds that undergo block addition of ethylene oxide and propylene oxide to allyl alcohol.

[0077] Specific product names for this type of polymer with reactive carbon-carbon unsaturated double bonds include those manufactured by Nippon Oil Company under the trade names UNIOX PKA-5001, UNIOX PKA-5002, UNIOX PKA-5003, UNIOX PKA-5004, UNIOX PKA-5005, UNIOX PKA-5006, UNIOX PKA-5007, and UNIOX. PKA-5008, UNIOX PKA-5009, UNIOX PKA-5010, UNIOX PKA-5011, UNIOX PKA-5012, UNIOX PKA-5013, UNIOX PKA-5014TF, UNIOX PKA-5015, UNIOX PKA-5016, UNIOX PKA-5017, etc.

[0078] The average molecular weight of such compounds having carbon-carbon unsaturated double bonds is preferably 100 or more, more preferably 200 or more. The average molecular weight of such polymers having reactive carbon-carbon unsaturated double bonds is preferably 10,000 or less, more preferably 8,000 or less.

[0079] Examples of monomers having carbon-carbon unsaturated double bonds include unsaturated carboxylic acid esters, aromatic vinyl compounds, unsaturated carboxylic acids, α,β-unsaturated nitrile compounds, and other unsaturated monomers.

[0080] As unsaturated carboxylic acid esters, (meth)acrylates are preferably used, such as alkyl esters and cycloalkyl esters of (meth)acrylate. As alkyl esters of (meth)acrylate, alkyl esters of (meth)acrylate having an alkyl group having 1 to 10 carbon atoms are preferred, such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, nonyl methacrylate, and decyl methacrylate. As cycloalkyl esters of (meth)acrylate, cyclohexyl methacrylate is an example. The illustrated unsaturated carboxylic acid esters can be used alone or in combination of two or more. Among these, alkyl esters of (meth)acrylic acid are preferred, and more preferably one or more selected from methyl (meth)acrylic acid, ethyl (meth)acrylic acid, n-butyl (meth)acrylic acid and 2-ethylhexyl (meth)acrylic acid.

[0081] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, etc., and one or more of these may be selected. Styrene is particularly preferred among the aromatic vinyl compounds.

[0082] Examples of unsaturated carboxylic acids include monocarboxylic acids or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and one or more of these can be used. Preferably, one or more of acrylic acid and methacrylic acid are used as the unsaturated carboxylic acid, and acrylic acid is more preferred.

[0083] Examples of α,β-unsaturated nitrile compounds include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, and vinylidene cyanide; one or more of these may be used. Among these, one or more selected from the group consisting of acrylonitrile and methacrylonitrile are preferred, with acrylonitrile being particularly preferred.

[0084] Other unsaturated monomers include alkylamides of unsaturated carboxylic acids such as (meth)acrylamide and N-hydroxymethylacrylamide; and aminoalkylamides of unsaturated carboxylic acids such as aminoethylacrylamide, dimethylaminomethylmethacrylamide, and methylaminopropylmethacrylamide. One or more of these monomers may be used.

[0085] The mixture of particles containing hydrogen sulfide groups (-SH) covalently fixed to the surface and compounds having carbon-carbon unsaturated double bonds in the first step may also contain a free radical generator. Using a free radical generator promotes the reaction between the hydrogen sulfide groups (-SH) fixed to the particle surface and the compounds having carbon-carbon unsaturated double bonds, which is therefore preferred.

[0086] Examples of free radical generators include: N,N′-azobisisobutyronitrile, 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionate amidine] tetrahydrate, dimethyl N,N′-azobis(2-methylpropionate), and other azo-based initiators; and benzoyl peroxide, lauroyl peroxide, and other organic peroxide-based initiators. The free radical generator is preferably added in an amount of 0.1 to 25 parts by weight relative to 100 parts by weight of the compound having a carbon-carbon unsaturated double bond.

[0087] 1.2. Second Step

[0088] The second step involves adding a peroxide and heating the particles obtained in the first step, in which the polymer is covalently linked to the surface via -S-. In the particles obtained in the first step, in which the polymer is covalently linked to the surface via -S-, unreacted hydrogen sulfide groups (-SH) remain on the particle surface. Therefore, by adding a suitable amount of peroxide and heating, the unreacted hydrogen sulfide groups (-SH) can be sulfonated, thereby converting them into the group represented by the following general formula (1).

[0089] -SO3 - M + ·····(1)

[0090] (M + (representing a monovalent cation)

[0091] In the above equation (1), M is used as + The monovalent cations represented are not limited to these, for example, H can be listed. + Li + Na + K + NH4 + That is, the abrasive particles obtained by the method of this embodiment not only have polymers linked to the particle surface via -S- and covalent bonds, but also possess at least one functional group selected from the group consisting of sulfonyl groups and their salts. Here, "sulfonyl salt" refers to the hydrogen ions contained in the sulfonyl group (-SO3H) being reacted with Li + Na + K + NH4 +Functional groups formed by substitution with monovalent cations. Furthermore, the abrasive particles manufactured by the method of this embodiment are abrasive particles in which the functional groups represented by the general formula (1) are fixed to the particle surface by covalent bonds, excluding abrasive particles in which compounds having the functional groups represented by the general formula (1) are physically or ionicly adsorbed on the particle surface.

[0092] Furthermore, in the second step, sometimes the -S- bonds, which serve as the sites for bonding the particle surface to the polymer chain, are oxidized and converted into bonds such as -SO- or -SO2-. Therefore, the abrasive particles manufactured by the method of this embodiment can be said to have polymer chains bonded via -SO- bonds. x -(x is an integer from 0 to 2) and is grafted onto the particle surface through covalent bonds.

[0093] 1.3. Characteristics of abrasive particles

[0094] 1.3.1. Alternating potential

[0095] The abrasive particles manufactured by the method of this embodiment preferably have an albedo of less than -10 mV in the chemical mechanical polishing composition, more preferably -60 mV or more but less than -10 mV, and particularly preferably -55 mV or more but less than -20 mV. The abrasive particles manufactured by the method of this embodiment can be added to the chemical mechanical polishing composition described later for use. The pH of the chemical mechanical polishing composition is preferably 2 or more but less than 5, as described later. In the region where the pH of the chemical mechanical polishing composition is 2 or more but less than 5, the surface of the silicon nitride film tends to be positively charged. Therefore, if the albedo of the abrasive particles in any region of the pH range of 2 or more but less than 5 is less than -10 mV, the abrasive particles tend to be locally present on the surface of the silicon nitride film due to the attraction based on the electrostatic interaction between the abrasive particles and the silicon nitride film, thus enabling high-speed polishing of the silicon nitride film. On the other hand, if the electrostatic potential of the abrasive particles in the region with a pH of 2 or higher and 5 or lower is -10 mV or higher, the electrostatic interaction between the abrasive particles and the silicon nitride film becomes weak or repulsive forces take effect, thus sometimes the abrasive speed of the silicon nitride film becomes insufficient. In order to ensure that the electrostatic potential of the abrasive particles in any region with a pH of 2 or higher and lower than 5 in the chemical mechanical polishing composition is less than -10 mV, for example, it can be adjusted by increasing or decreasing the amount of thiol-containing silane coupling agent added in the method described above for fixing hydrogen sulfide groups (-SH) to the surface of silicon oxide particles via covalent bonds.

[0096] The zeta potential of abrasive particles can be measured using a zeta potential measuring device based on the laser Doppler method and conventional methods. Examples of such zeta potential measuring devices include the "zeta potential analyzer" manufactured by Brookhaven Instruments, the "ELSZ-1000ZS" manufactured by Otsuka Electronics Co., Ltd., and the "DT-300" manufactured by Dispersion Technology Co., Ltd.

[0097] 1.3.2. Average secondary particle size

[0098] The average secondary particle size of the abrasive grains manufactured by the method of this embodiment is preferably 30 nm or more, more preferably 40 nm or more, and particularly preferably 50 nm or more. The average secondary particle size of the abrasive grains manufactured by the method of this embodiment is preferably 100 nm or less, more preferably 95 nm or less, and particularly preferably 90 nm or less. If the average secondary particle size of the abrasive grains is within the aforementioned range, it is possible to suppress the generation of grinding defects while grinding the silicon nitride film to be ground at a practical grinding speed. The average secondary particle size of the abrasive grains can be measured using a dynamic light scattering particle size distribution measuring device. Examples of such a dynamic light scattering particle size distribution measuring device include the "Nanoparticle Analysis Device SZ-100" manufactured by Horiba Corporation.

[0099] 2. Composition for chemical mechanical grinding

[0100] A chemical mechanical polishing composition according to one embodiment of the present invention contains abrasive grains manufactured by the method described above and a liquid medium. Hereinafter, each component contained in the chemical mechanical polishing composition of this embodiment will be described in detail.

[0101] 2.1. Abrasive particles

[0102] The chemical mechanical polishing composition of this embodiment contains abrasive grains manufactured by the method described above. As described above, on the surface of the abrasive grains, polymer chains are grafted by covalent bonds, and the abrasive grains have functional groups represented by the following general formula (1) on their surface.

[0103] -SO3 - M + ·····(1)

[0104] (M + (representing a monovalent cation)

[0105] Furthermore, in the abrasive particles obtained through the second step, sometimes the -S- bonds, which serve as the sites for bonding the particle surface to the polymer chain, are oxidized and converted into bonds such as -SO- or -SO2-. Therefore, the abrasive particles can be considered as polymer chains bonded via -SO-... x - (x is an integer from 0 to 2) and abrasive particles grafted onto its surface through covalent bonds.

[0106] The manufacturing method or characteristics of the abrasive grains are as described above, and therefore, the description is omitted.

[0107] When the total mass of the chemical mechanical polishing composition is set to 100% by mass, the content of abrasive particles is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more. When the total mass of the chemical mechanical polishing composition is set to 100% by mass, the content of abrasive particles is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 6% by mass or less. If the content of abrasive particles is within the aforementioned range, it is possible to achieve high-speed polishing of the silicon nitride film to be polished, and the storage stability of the chemical mechanical polishing composition becomes good.

[0108] 2.2. Liquid medium

[0109] The chemical mechanical polishing composition of this embodiment contains a liquid medium. Examples of liquid media include water, a mixture of water and alcohol, and a mixture containing water and an organic solvent miscible with water. Among these, water or a mixture of water and alcohol is preferred, and water is more preferred. There are no particular limitations on the type of water used, but pure water is preferred. Water can be prepared as a remainder of the constituent materials of the chemical mechanical polishing composition, and the water content is not particularly limited.

[0110] 2.3. Other additives

[0111] The chemical mechanical polishing composition of this embodiment may also contain additives such as acidic compounds, water-soluble polymers, surfactants, oxidants, corrosion inhibitors, and pH adjusters, as needed. The additives will be described below.

[0112] <Acidic compounds>

[0113] The chemical mechanical polishing composition of this embodiment may also contain an acidic compound. By containing an acidic compound, a synergistic effect with the abrasive grains can be obtained, thereby increasing the polishing speed of the silicon nitride film.

[0114] Examples of acidic compounds include both organic and inorganic acids. Examples of organic acids include: saturated carboxylic acids such as malonic acid, citric acid, malic acid, tartaric acid, oxalic acid, lactic acid, and iminodiacetic acid; unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-butenoic acid, 2-methyl-3-butenoic acid, 2-hexenoic acid, and 3-methyl-2-hexenoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesoconic acid, 2-pentenic acid, itaconic acid, allylmalonic acid, isopropyl succinic acid, 2,4-hexadienoic acid, and acetylene dicarboxylic acid; and aromatic carboxylic acids such as trimellitic acid and their salts. Examples of inorganic acids include: phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and their salts. These acidic compounds can be used alone or in combination of two or more.

[0115] When the chemical mechanical polishing composition of this embodiment contains an acidic compound, when the total mass of the chemical mechanical polishing composition is set to 100% by mass, the content of the acidic compound is preferably 0.001% to 5% by mass, more preferably 0.003% to 1% by mass, and particularly preferably 0.005% to 0.5% by mass.

[0116] <Water-soluble polymers>

[0117] The chemical mechanical polishing composition of this embodiment may also contain a water-soluble polymer. The water-soluble polymer adsorbs onto the surface of the silicon nitride film, thereby reducing polishing friction. Through this effect, the formation of depressions in the silicon nitride film can be significantly reduced.

[0118] Examples of water-soluble polymers include: polyethyleneimine, poly(meth)acrylamide, poly(N-alkyl(meth)acrylamide), poly(meth)acrylic acid, polyoxyethylene alkylamine, polyvinyl alcohol, polyvinyl alkyl ether, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, copolymers of (meth)acrylic acid and maleic acid, and poly(meth)acrylamine and other high-molecular-weight amine compounds. Among these, by adding thermoresponsive polymers such as polyvinyl methyl ether and poly(N-isopropylacrylamide) or high-molecular-weight amine compounds such as poly(meth)acrylamine, it is possible to more effectively reduce the formation of depressions in the silicon nitride film without reducing the grinding speed of the silicon nitride film.

[0119] The weight-average molecular weight (Mw) of the water-soluble polymer is preferably 1,000 to 1,000,000, more preferably 3,000 to 800,000. If the weight-average molecular weight of the water-soluble polymer is within this range, it is easier to adsorb onto the surface of the silicon nitride film, thereby further reducing abrasive friction. As a result, the formation of depressions in the silicon nitride film can be reduced more effectively. Furthermore, the term "weight-average molecular weight (Mw)" in this specification refers to the weight-average molecular weight converted from polyethylene glycol as determined by gel permeation chromatography (GPC).

[0120] When the chemical mechanical polishing composition of this embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.005% to 0.5% by mass, more preferably 0.01% to 0.2% by mass, when the total mass of the chemical mechanical polishing composition is set to 100% by mass.

[0121] Furthermore, while the content of the water-soluble polymer also depends on the weight average molecular weight (Mw) of the water-soluble polymer, it is preferably adjusted so that the viscosity of the chemical mechanical polishing composition at 25°C is 0.5 mPa·s or more but less than 10 mPa·s. If the viscosity of the chemical mechanical polishing composition at 25°C is 0.5 mPa·s or more but less than 10 mPa·s, it is easy to polish the silicon nitride film at high speed, and because the viscosity is appropriate, the chemical mechanical polishing composition can be stably supplied to the polishing cloth.

[0122] <surfactants>

[0123] The chemical mechanical polishing composition of this embodiment may also contain a surfactant. By containing a surfactant, it is possible to impart a suitable viscosity to the chemical mechanical polishing composition. The viscosity of the chemical mechanical polishing composition is preferably adjusted to be 0.5 mPa·s or more and less than 10 mPa·s at 25°C.

[0124] There are no particular limitations on surfactants; examples include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0125] Examples of anionic surfactants include carboxylates such as fatty acid soaps and alkyl ether carboxylates; sulfonates such as alkylbenzene sulfonates, alkylnaphthalene sulfonates, and α-olefin sulfonates; sulfates such as higher alcohol sulfates, alkyl ether sulfates, and polyoxyethylene alkylphenyl ether sulfates; and fluorinated surfactants such as perfluoroalkyl compounds. Examples of cationic surfactants include aliphatic amine salts and aliphatic ammonium salts. Examples of nonionic surfactants include nonionic surfactants with triple bonds such as ethynylene glycol, ethynylene glycol ethylene oxide adducts, and ethynyl alcohol; and polyethylene glycol-type surfactants. These surfactants can be used alone or in combination of two or more.

[0126] When the chemical mechanical polishing composition of this embodiment contains a surfactant, when the total mass of the chemical mechanical polishing composition is set to 100% by mass, the surfactant content is preferably 0.001% to 5% by mass, more preferably 0.003% to 3% by mass, and particularly preferably 0.005% to 1% by mass.

[0127] Oxidizing agents

[0128] The chemical mechanical polishing composition of this embodiment may also contain an oxidizing agent. By containing an oxidizing agent, the silicon nitride film can be oxidized to form a fragile modified layer, thus increasing the polishing speed.

[0129] Examples of oxidizing agents include: ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, dicerium ammonium nitrate, potassium hypochlorite, ozone, potassium periodate, and peracetic acid. Among these oxidizing agents, ammonium persulfate, potassium persulfate, and hydrogen peroxide are preferred, and hydrogen peroxide is more preferred, considering both oxidizing power and ease of processing. These oxidizing agents can be used alone or in combination of two or more.

[0130] When the chemical mechanical polishing composition of this embodiment contains an oxidant, the content of the oxidant is preferably 0.1% to 5% by mass, more preferably 0.3% to 4% by mass, and particularly preferably 0.5% to 3% by mass, when the total mass of the chemical mechanical polishing composition is set to 100% by mass. Furthermore, since the oxidant is easily decomposed in the chemical mechanical polishing composition, it is ideal to add it before the CMP polishing step.

[0131] <Corrosion Inhibitor>

[0132] The chemical mechanical polishing composition of the present embodiment may also contain a corrosion inhibitor. Examples of the corrosion inhibitor include benzotriazole and its derivatives. Here, the benzotriazole derivative refers to a substance obtained by substituting one or more hydrogen atoms of benzotriazole with, for example, a carboxyl group, a methyl group, an amino group, a hydroxyl group, etc. Specific examples of the benzotriazole derivative include 4-carboxybenzotriazole, 7-carboxybenzotriazole, benzotriazole butyl ester, 1-hydroxymethylbenzotriazole, 1-hydroxybenzotriazole, and their salts, etc.

[0133] When the chemical mechanical polishing composition of the present embodiment contains a corrosion inhibitor, when the total mass of the chemical mechanical polishing composition is set to 100% by mass, the content of the corrosion inhibitor is preferably 1% by mass or less, and more preferably 0.001% by mass to 0.1% by mass.

[0134] <pH adjuster>

[0135] The chemical mechanical polishing composition of the present embodiment may also contain a pH adjuster as needed. Examples of the pH adjuster include: bases such as potassium hydroxide, ethylenediamine, monoethanolamine, tetramethylammonium hydroxide (Tetramethyl ammonium hydroxide, TMAH), tetraethylammonium hydroxide (Tetraethyl ammonium hydroxide, TEAH), ammonia, etc., and one or more of them can be used.

[0136] 2.4. pH

[0137] The pH of the chemical mechanical polishing composition of the present embodiment is not particularly limited, preferably 2 or more and 5 or less, and more preferably 2 or more and 4 or less. In the region where the pH of the chemical mechanical polishing composition is 2 or more and 5 or less, the surface of the silicon nitride film is likely to be positively charged, and the zeta potential of the abrasive grains is likely to become less than -10 mV. Therefore, due to the gravitational force based on the electrostatic interaction between the abrasive grains and the silicon nitride film, the abrasive grains are likely to be locally present on the surface of the silicon nitride film, so high-speed polishing of the silicon nitride film can be achieved. In addition, if the pH of the chemical mechanical polishing composition is 2 or more and 5 or less, the dispersibility of the abrasive grains is improved, and thus the storage stability of the chemical mechanical polishing composition becomes good, so it is preferred.

[0138] Furthermore, the pH of the chemical mechanical polishing composition of the present embodiment can be adjusted, for example, by appropriately increasing or decreasing the content of the acidic compound or the pH adjuster, etc.

[0139] In this specification, the so-called pH refers to the hydrogen ion index, and its value can be measured under the conditions of 25 °C and 1 atmosphere using a commercially available pH meter (for example, manufactured by Horiba, Ltd., tabletop pH meter).

[0140] 2.5. Applications

[0141] The chemical mechanical polishing composition of this embodiment can be used as an abrasive for polishing materials that are positively charged during chemical mechanical polishing, among various materials constituting semiconductor devices. The chemical mechanical polishing composition of this embodiment is particularly suitable for polishing silicon nitride films in materials that are positively charged during chemical mechanical polishing, and can be used, for example, for separating components in semiconductor manufacturing processes.

[0142] 2.6. Preparation method of composition for chemical mechanical grinding

[0143] The chemical mechanical grinding composition of this embodiment can be prepared by dissolving or dispersing the components in a liquid medium such as water. There are no particular limitations on the method of dissolution or dispersion; any method can be used as long as the components can be dissolved or dispersed uniformly. Furthermore, there are no particular limitations on the mixing order or method of the components.

[0144] In addition, the chemical mechanical grinding composition of this embodiment can also be prepared as a concentrated stock solution and diluted with a liquid medium such as water before use.

[0145] 3. Chemical mechanical grinding method

[0146] One embodiment of the polishing method of the present invention includes a step of polishing a material that is positively charged during chemical mechanical polishing (CMP) among various materials constituting a semiconductor device using the chemical mechanical polishing composition described above. The polishing method of this embodiment is suitable for selectively polishing silicon nitride films in materials that are positively charged during CMP, and can be applied, for example, to the separation between components in a semiconductor manufacturing process. Hereinafter, as a specific example of the CMP method of this embodiment, an accompanying document will be used... Figure 1 Explain the separation between components.

[0147] 3.1. The object being processed

[0148] Figure 1 This is a cross-sectional view schematically showing the manufacturing steps of the processed object with components separated. The processed object 100 is manufactured by proceeding through the following steps (1) to (3).

[0149] (1) First, as Figure 1As shown, a silicon wafer 10 is prepared. Functional devices such as transistors (not shown) can be formed on the silicon wafer 10. Next, a thermal oxide film 12 is formed on the silicon wafer 10 using a thermal oxidation method. Next, a silicon nitride film 14 is deposited on the thermal oxide film 12. The silicon nitride film 14 functions as a barrier film. Regarding the thermal oxide film 12, if the silicon nitride film 14 is formed directly on the silicon wafer 10, it may sometimes have an adverse effect on the silicon wafer 10. In order to prevent the silicon wafer 10 and the silicon nitride film 14 from peeling off due to the difference in thermal expansion, a thermal oxide film 12 is provided between the silicon wafer 10 and the silicon nitride film 14.

[0150] (2) Then, the silicon nitride film 14 is patterned. The obtained pattern is used as a mask to form the groove 16 by dry etching.

[0151] (3) Subsequently, a silicon oxide film 18 is grown on the inside of the tank 16 by chemical vapor deposition (CVD).

[0152] Through the above steps, the processed object 100 is formed.

[0153] 3.2. Chemical Mechanical Grinding Method

[0154] 3.2.1. First grinding step

[0155] Figure 2 This is a schematic cross-sectional view of the workpiece at the end of the first grinding step. For example... Figure 2 As shown, in the first grinding step, using Figure 4 The polishing apparatus 200 shown polishes a silicon oxide film 18 to which a silicon nitride film 14 is embedded as a barrier using chemical mechanical polishing (CMP). In the first polishing step, a chemical mechanical polishing composition for silicon oxide films is used for CMP.

[0156] 3.2.2. Second grinding step

[0157] Figure 3 This is a schematic cross-sectional view of the workpiece at the end of the second grinding step. (Example) Figure 3 As shown, in the second grinding step, using Figure 4 The polishing apparatus 200 shown uses the chemical mechanical polishing composition to polish the silicon nitride film 14 and the silicon oxide film 18 embedded in the trench 16 to planarize them. The chemical mechanical polishing composition can selectively polish the silicon nitride film 14, thus making it suitable for a second polishing step. Subsequently, the thermal oxide film 12 is removed by continuing CMP or performing wet etching, thereby enabling so-called inter-element separation.

[0158] 3.3. Chemical Mechanical Grinding Apparatus

[0159] In the first and second grinding steps, for example, the following methods can be used: Figure 4 The grinding apparatus 200 shown. Figure 4 This is a schematic perspective view of the polishing apparatus 200. The first and second polishing steps are performed as follows: slurry (a chemical mechanical polishing composition) 44 is supplied from the slurry supply nozzle 42, and while rotating the turntable 48 to which the polishing cloth 46 is attached, the carrier head 52 holding the semiconductor substrate 50 is brought into contact with it. Furthermore, in... Figure 4 The water supply nozzle 54 and the dresser 56 are also shown in the image.

[0160] The grinding load of the bearing head 52 can be selected within the range of 10 hPa to 980 hPa, preferably 30 hPa to 490 hPa. Furthermore, the rotational speeds of the turntable 48 and the bearing head 52 can be appropriately selected within the range of 10 rpm to 400 rpm, preferably 30 rpm to 150 rpm. The flow rate of the slurry (chemical mechanical grinding composition) 44 supplied from the slurry supply nozzle 42 can be selected within the range of 10 mL / min to 1000 mL / min, preferably 50 mL / min to 400 mL / min.

[0161] Commercially available grinding devices include, for example: EPO-112 and EPO-222 manufactured by Ebara Seisakusho; LGP-510 and LGP-552 manufactured by Lapmaster SFT; Mirra and Reflexion manufactured by Applied Materials; POLI-400L manufactured by G&P Technology; and Reflexion LK manufactured by AMAT.

[0162] 4. Example

[0163] The present invention will now be described through examples, but the invention is not limited to these examples in any way. Furthermore, unless otherwise specified, "parts" and "%" in these examples refer to mass.

[0164] 4.1. Manufacturing of abrasive particles

[0165] 4.1.1. Synthesis of silica particles A

[0166] A monomer solution was prepared by mixing 100 parts by weight of tetramethyl orthosilicate (manufactured by Tamo Chemical Industry Co., Ltd.) and 26.8 parts by weight of methanol at room temperature and pressure. Then, 61.2 parts by weight of ammonia solution (28% by weight), 98.6 parts by weight of water, and 791.4 parts by weight of methanol were added to a reaction vessel. While stirring at 35°C, the prepared monomer solution was slowly added over 30 minutes. The mixture was then heated to 90°C and maintained for 6 hours. Subsequently, 341 parts by weight of water were added, and the reaction solution was concentrated under reduced pressure to prepare a dispersion of silica particles A with a silica conversion concentration of 20% by weight.

[0167] 4.1.2. Synthesis of Silica Particles B

[0168] At room temperature and pressure, while stirring 1216 parts by mass of water, 100 parts by mass of tetramethyl orthosilicate (manufactured by Tama Chemical Industry Co., Ltd.) were added, and the mixture was allowed to react for 1 hour to prepare a hydrolysate of tetramethyl orthosilicate. Then, while stirring and heating a mixture of 0.2 parts by mass of tetramethylammonium hydroxide (manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd., 1N aqueous solution) and 1737 parts by mass of water at 80°C, the entire hydrolysate of the previously prepared tetramethyl orthosilicate was added at a rate of 6 mL / min. Furthermore, as the pH of the solution decreased to 6.35 during the addition process, 1N aqueous solution of tetramethylammonium hydroxide was added sequentially to adjust the pH of the reaction solution to approximately 8. After the addition was complete, the solution was filtered using a 90 μm mesh filter, and finally concentrated under reduced pressure to prepare a dispersion of silica particles B with a silica conversion concentration of 20% by mass and bead-like aggregates.

[0169] 4.1.3. Synthesis of silica particles C

[0170] While stirring and heating a mixture of 0.2 parts by mass of triethanolamine (manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd.) and 557 parts by mass of water at 70°C, 100 parts by mass of tetramethyl orthosilicate (manufactured by Tama Chemical Industry Co., Ltd.) were added over 3 hours. The mixture was then heated to 90°C and concentrated under reduced pressure to a total volume of 324 parts by mass. The reaction solution was then cooled to 40°C, and 3354 parts by mass of water and 3.6 parts by mass of triethanolamine were added. The mixture was then heated to 80°C, and 1464 parts by mass of tetramethyl orthosilicate (manufactured by Tama Chemical Industry Co., Ltd.) were added over 3 hours. After the addition was complete, the reaction solution was heated to 90°C, and 2114 parts by mass of water were added and concentrated under reduced pressure to produce a dispersion of silica particles C with a silica conversion concentration of 20% by mass and multiple protrusions on the surface.

[0171] The term "protrusion" here refers to a protrusion with a sufficiently small height and width compared to the particle size of silica particles C. The number of protrusions on the surface of silica particles C is preferably three or more per particle, more preferably five or more. Silica particles C can also be described as particles with a special shape, such as a confetti-like appearance.

[0172] 4.2. Example 1

[0173] 4.2.1. Preparation of abrasive particles

[0174] 100 parts by mass of the dispersion of silica particles A prepared above were heated to 60°C. While stirring vigorously, 0.12 parts by mass of (3-mercaptopropyl)trimethoxysilane (manufactured by Fujifilm and Koko Pure Chemical Industries Co., Ltd.) as a grafting agent were added dropwise, and stirring was continued at 60°C for 2 hours.

[0175] Subsequently, the solution was heated to 80°C, and then 0.32 parts by weight of allylated polyether (manufactured by Nippon Oil Co., Ltd., product name "UNIOX PKA-5013", average molecular weight 2000) as the graft polymer was added, followed by 0.07 parts by weight of free radical generator (manufactured by Fujifilm and Koko Pure Chemical Industries Co., Ltd., product name "VA-057"). The solution was then maintained at 80°C for 3 hours.

[0176] Finally, the solution was cooled to 60°C, and 0.54 parts by weight of hydrogen peroxide water (manufactured by Fujifilm and Koko Pure Chemical Industries Co., Ltd., 35% by weight aqueous solution) was added. The mixture was kept at 60°C for 2 hours to produce grinding particles.

[0177] 4.2.2. Preparation of compositions for chemical mechanical grinding

[0178] The prepared abrasive particles were added at a silica concentration of 2% by mass, followed by the addition of phosphoric acid and water to achieve a pH of 2.1. The mixture was then filtered using a 0.3 μm filter to obtain a chemical mechanical polishing composition.

[0179] 4.2.3. Evaluation of compositions for chemical mechanical grinding

[0180] <Determination of Phenolic Potential>

[0181] The side potential (surface charge) of the abrasive particles contained in the above-prepared chemical mechanical polishing composition was determined using an ultrasonic particle size distribution-side potential measuring device (Dispersion Technology, model "DT-300"). The results are shown in Table 1 below.

[0182] <Determination of average secondary particle size>

[0183] The average secondary particle size of the abrasive particles contained in the above-prepared chemical mechanical polishing composition was determined using a Horiba SZ-100 nanoparticle analysis apparatus. The results are shown in Table 1 below.

[0184] <Grinding Speed ​​Evaluation>

[0185] Using the chemical mechanical polishing (CMP) composition prepared above, 12-inch silicon substrates with a 250nm silicon nitride film, 12-inch silicon substrates with a 2000nm silicon oxide film, 12-inch silicon substrates with a 200nm amorphous silicon film, and 12-inch silicon substrates with a 500nm polycrystalline silicon film were used as polishing subjects. CMP was performed using a CMP apparatus (G&P Technology, model "Poli-400L") under the following conditions. Furthermore, the film thickness before and after polishing was measured using a non-contact optical film thickness measuring device (Nanometrics Japan, model "NanoSpec 6100").

[0186] (Grinding conditions)

[0187] • Grinding pad: Manufactured by Dow, model "IK4010"

[0188] • Load capacity of the bearing head: 129g / cm 2

[0189] • Press plate speed: 100 rpm

[0190] • Grinding head speed: 90 rpm

[0191] • Chemical mechanical grinding composition feed rate: 50 mL / min

[0192] (Evaluation Criteria)

[0193] • When the grinding speed ratios relative to silicon oxide films, amorphous silicon films, and polycrystalline silicon films are all above 5.0, silicon nitride films can be selectively ground, and therefore are judged as good.

[0194] • If at least any one of the grinding speed ratios relative to the silicon oxide film, amorphous silicon film, and polycrystalline silicon film of silicon nitride is less than 5.0, there is a situation where the silicon nitride film cannot be selectively ground, and therefore it is judged as defective.

[0195] 4.3. Examples 2 to 18

[0196] In “4.2.1. Preparation of abrasive particles” of Example 1, the types and amounts of silica particles, mercapto-containing silane coupling agents, compounds having carbon-carbon unsaturated double bonds, free radical generators, and hydrogen peroxide shown in Table 1 or Table 2 below are used. Otherwise, the abrasive particles are prepared in the same manner as in Example 1.

[0197] The prepared abrasive particles were added at a silica conversion concentration of 2% by mass, followed by the addition of phosphoric acid and water at the pH values ​​shown in Table 1 or Table 2 below. The mixture was then filtered using a 0.3 μm pore size filter to obtain various chemimechanical grinding compositions. Using the obtained chemimechanical grinding compositions, the anisotropic potential and average secondary particle size of the abrasive particles were measured in the same manner as in Example 1 to evaluate the grinding speed. The results are shown in Table 1 or Table 2 below.

[0198] 4.4. Comparative Example 1

[0199] Silica particles A without polymer chains grafted onto their surface were used directly as abrasive particles. Otherwise, a chemical mechanical polishing composition was prepared in the same manner as in Example 1, and the polishing speed was evaluated. The results are shown in Table 2 below.

[0200] 4.5. Comparative Example 2

[0201] Although the abrasive particles used were those from silica particles A that had undergone a surface reaction with a thiol-containing silane coupling agent, resulting in hydrogen sulfide groups (-SH) being covalently fixed to the surface, but without polymer chains grafted onto them, the chemical mechanical polishing composition was prepared in the same manner as in Example 1, and the polishing speed was evaluated. The results are shown in Table 2 below.

[0202] 4.6. Comparative Example 3

[0203] Except for the following abrasive particles, namely particles in which hydrogen sulfide groups (-SH) are covalently fixed on the surface of silica particles A by reacting the surface with a thiol-containing silane coupling agent, and abrasive particles with -SO3H groups on the surface but without polymer chains grafted, which are treated with an oxidant, a chemical mechanical polishing composition was prepared in the same manner as in Example 1, and the polishing speed was evaluated. The results are shown in Table 2 below.

[0204] 4.7. Comparative Example 4

[0205] After reacting the surface of silica particles A with a thiol-containing silane coupling agent to covalently fix hydrogen sulfide (-SH) groups onto the surface, mixing the particles, a compound with carbon-carbon unsaturated double bonds, and a free radical generator, and heating the mixture, abrasive particles are directly prepared without adding peroxide. However, due to agglomeration, it is impossible to filter the mixture using a 0.3 μm pore size filter to prepare a chemical mechanical polishing composition, and the polishing speed cannot be evaluated.

[0206] 4.8. Evaluation Results

[0207] Tables 1 and 2 below show the reagents and amounts used in the manufacturing steps of the abrasive particles for each embodiment and comparative example, as well as the evaluation results of the chemical mechanical polishing compositions.

[0208] [Table 1]

[0209]

[0210]

[0211] The reagents listed in Tables 1 and 2 above are the commercially available products described below.

[0212] <Silane coupling agents containing thiol groups>

[0213] (3-Mercaptopropyl)trimethoxysilane manufactured by Fujifilm and Koko Pure Chemical Industries, Ltd.

[0214] <Compounds with carbon-carbon unsaturated double bonds>

[0215] • PKA-5001: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5001", average molecular weight 200, allylated polyether, EO chain, terminal OH

[0216] • PKA-5003: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5003", average molecular weight 450, allylated polyether, EO chain, terminal OH

[0217] • PKA-5005: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5005", average molecular weight 1500, allylated polyether, EO chain, terminal OH

[0218] • PKA-5008: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5008", average molecular weight 450, allylated polyether, EO chain, terminal CH3

[0219] • PKA-5010: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5010", average molecular weight 2000, allylated polyether, EO chain, terminal CH3

[0220] • PKA-5011: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5011", average molecular weight 7500, allylated polyether, EO / PO chain, terminal OH

[0221] • PKA-5012: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5012", average molecular weight 2000, allylated polyether, EO / PO chain, terminal OH

[0222] • PKA-5013: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5013", average molecular weight 2000, allylated polyether, EO / PO chain, terminal OH

[0223] • PKA-5014TF: Manufactured by Nichiyu Corporation, product name "UNIOX PKA-5014TF", average molecular weight 1500, allylated polyether, PO chain, terminal OH

[0224] Free radical generators

[0225] VA-057: Manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd., 2,2′-azobis[N-(2-carboxyethyl)-2-methylpropionic acid amidine] tetrahydrate, a water-soluble azo polymerization initiator.

[0226] <Peroxides>

[0227] • Hydrogen peroxide (35% aqueous solution), manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.

[0228] In Examples 1 to 18, it can be seen that by using polymer chains via -SO x -(x=0~2) and abrasive grains grafted onto the surface via covalent bonds can selectively abrade silicon nitride films relative to silicon oxide films, amorphous silicon films, and polycrystalline silicon films, achieving excellent abrasive characteristics.

[0229] Comparative Examples 1 to 3, because they did not use abrasive grains with polymer chains grafted onto the surface, could not selectively grind the silicon nitride film, and therefore could not achieve good grinding characteristics. In Comparative Example 4, because agglomeration occurred, it was impossible to use a 0.3 μm pore size filter to prepare a chemical mechanical polishing composition, and therefore it was impossible to evaluate the grinding speed.

[0230] Based on the above results, it can be seen that the chemical mechanical polishing composition of this invention can selectively and rapidly polish silicon nitride films relative to silicon oxide films, amorphous silicon films, and polycrystalline silicon films, thereby achieving excellent polishing characteristics.

[0231] This invention is not limited to the described embodiments and various modifications are possible. For example, this invention includes structures that are substantially the same as those described in the embodiments (e.g., structures with the same function, method, and result, or structures with the same purpose and effect). Additionally, this invention includes structures obtained by replacing non-essential parts of the structures described in the embodiments. Furthermore, this invention includes structures that perform the same function and effect as those described in the embodiments or structures that achieve the same purpose. Additionally, this invention includes structures obtained by adding known techniques to the structures described in the embodiments.

Claims

1. A method for manufacturing abrasive grains, the method comprising: The first step is to heat the mixture, which contains particles with hydrogen sulfide groups fixed on the surface by covalent bonds and compounds having carbon-carbon unsaturated double bonds. as well as The second step, following the first step, involves adding peroxide and heating. The abrasive particles have functional groups represented by the following general formula (1) on their surface. M + It represents a monovalent cation.

2. The method for manufacturing abrasive particles according to claim 1, wherein, The mixture in the first step also contains a free radical generator.

3. The method for manufacturing abrasive particles according to claim 1 or 2, wherein, The compound having carbon-carbon unsaturated double bonds has an average molecular weight of 100 to 10,000.

4. The method for manufacturing abrasive particles according to claim 1 or 2, wherein, In a chemical mechanical polishing composition containing the abrasive particles, the side potential of the abrasive particles is less than -10 mV.

5. A composition for chemical mechanical grinding, comprising: Abrasive grains, manufactured by the method for manufacturing abrasive grains as described in any one of claims 1 to 4; and Liquid medium.

6. A chemical mechanical grinding composition comprising abrasive particles and a liquid medium, wherein, The polymer chains are covalently grafted onto the surface of the abrasive particles, and The abrasive particles have functional groups represented by the following general formula (1) on their surface. M + It represents a monovalent cation.

7. A chemical mechanical grinding composition comprising abrasive particles and a liquid medium, wherein, Polymer chains via -SO x - and is grafted onto the surface of the abrasive grains via covalent bonds, where x is an integer from 0 to 2. The abrasive particles have functional groups represented by the following general formula (1) on their surface. M + It represents a monovalent cation.

8. The chemical mechanical polishing composition according to any one of claims 5 to 7, used for polishing a material that is positively charged during chemical mechanical polishing from among a variety of materials constituting a semiconductor device.

9. The chemical mechanical grinding composition according to claim 8, wherein, The positively charged material is a silicon nitride film.

10. A chemical mechanical polishing method comprising the step of polishing a material that is positively charged during chemical mechanical polishing among a variety of materials constituting a semiconductor device using a chemical mechanical polishing composition as described in any one of claims 5 to 9.

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