Chemical mechanical polishing composition and chemical mechanical polishing method

Abstract

The present invention provides a chemical mechanical polishing composition and a chemical mechanical polishing method, which can polish semiconductor substrates containing conductive metals such as tungsten and cobalt at high speed and flatness, and can reduce surface defects after polishing. The chemical mechanical polishing composition of the present invention contains: (A) silica particles containing functional groups represented by the following general formula (1); and (B) a silane compound. ‑ M + ·····(1)(M + represents a monovalent cation).

Description

Technical Field

[0001] The present invention relates to a chemical mechanical polishing composition and a chemical mechanical polishing method. Background Art

[0002] The miniaturization of wiring layers, including wiring and plugs, formed within semiconductor devices is progressing rapidly. In response to this trend, chemical mechanical polishing (hereinafter referred to as "CMP") is being used to planarize wiring layers. The ultimate goal of this CMP process is to flatten the polished surface after polishing, resulting in a defect-free and corrosion-free surface. Therefore, chemical mechanical polishing compositions used in CMP are evaluated based on properties such as material removal rate, surface defect rate after polishing, and metal corrosion prevention after polishing.

[0003] In recent years, with the further miniaturization of wiring layers, tungsten (W) and cobalt (Co) have begun to be used as conductive metals. Consequently, there is a need to be able to efficiently remove excess tungsten or cobalt by CMP, while also suppressing tungsten or cobalt corrosion and achieving a good surface condition. Chemical mechanical polishing compositions containing various additives have been proposed for chemical mechanical polishing of tungsten or cobalt (see, for example, Patent Documents 1 and 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2017-514295

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-030831 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] With the widespread use of semiconductor wafers containing conductive metals such as tungsten and cobalt, there is a demand for chemical mechanical polishing compositions and chemical mechanical polishing methods that can polish semiconductor substrates containing conductive metals such as tungsten and cobalt at high speed and flatly while reducing surface defects after polishing.

[0010] Technical means to solve the problem

[0011] One embodiment of the chemical mechanical polishing composition of the present invention comprises:

[0012] (A) silica particles containing a functional group represented by the following general formula (1); and

[0013] (B) a silane compound,

[0014] -COO - M + ·····(1)

[0015] (M + represents a monovalent cation).

[0016] In one embodiment of the chemical mechanical polishing composition, the composition may be:

[0017] When the total mass of the chemical mechanical polishing composition is set to 100 mass %,

[0018] The content of the component (A) is 0.1% by mass or more and 10% by mass or less,

[0019] The content of the component (B) is 0.0001% by mass or more and 0.02% by mass or less.

[0020] In any form of the chemical mechanical polishing composition, the composition may be:

[0021] The component (A) is silica particles having functional groups represented by the general formula (1) fixed to the surface via covalent bonds.

[0022] In any form of the chemical mechanical polishing composition, the composition may be:

[0023] The component (B) is one or more compounds selected from the group consisting of compounds represented by the following general formula (2), general formula (3) and general formula (4).

[0024] Si(OR 1 )4·····(2)

[0025] SiR 2 m (OR 3 ) n (R 4 -NR 5 2) p ·····(3)

[0026] SiR 2 m (OR 3 ) n R 5 p ·····(4)

[0027] (In formula (2), there are multiple R 1 Each independently represents a monovalent hydrocarbon group; in formula (3), R 4 represents a divalent hydrocarbon group; in formula (3) and formula (4), R 2 and R 3 Each independently represents a monovalent hydrocarbon group, R5 Each independently represents a monovalent organic group having 1 to 10 carbon atoms and containing or not containing a heteroatom, or a hydrogen atom, m is an integer of 0 to 2, n is an integer of 1 to 3, p is 1 or 2, and m+n+p=4).

[0028] In any form of the chemical mechanical polishing composition, the composition may be:

[0029] The component (B) is one or more selected from tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraphenoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, 3-triethoxysilylpropylsuccinic anhydride, 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

[0030] In any aspect of the chemical mechanical polishing composition,

[0031] It may also contain organic acids.

[0032] In any aspect of the chemical mechanical polishing composition,

[0033] It may also contain an oxidizing agent.

[0034] In any form of the chemical mechanical polishing composition, the composition may be:

[0035] The pH is 2 or higher and 5 or lower.

[0036] One aspect of the chemical mechanical polishing method of the present invention includes:

[0037] A step of polishing a semiconductor substrate using any of the chemical mechanical polishing compositions described above.

[0038] In one aspect of the chemical mechanical polishing method, the following steps may be performed:

[0039] The semiconductor substrate includes a portion containing at least one selected from the group consisting of silicon oxide and tungsten.

[0040] Effects of the Invention

[0041] According to the chemical mechanical polishing composition of the present invention, a semiconductor substrate containing a conductive metal such as tungsten or cobalt can be polished flatly at high speed, and surface defects after polishing can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1This is a cross-sectional view schematically showing an object to be processed used in chemical mechanical polishing according to this embodiment.

[0043] Figure 2 It is a cross-sectional view schematically showing the object to be processed after the first polishing step.

[0044] Figure 3 It is a cross-sectional view schematically showing the object to be processed after the second polishing step.

[0045] Figure 4 It is a perspective view schematically showing a chemical mechanical polishing apparatus.

[0046] Explanation of symbols

[0047] 10: Matrix

[0048] 12: Silicon oxide film

[0049] 14: Through hole

[0050] 16: Barrier metal film

[0051] 18: Tungsten film

[0052] 42: Slurry supply nozzle

[0053] 44: Chemical mechanical polishing composition (slurry)

[0054] 46: Abrasive cloth

[0055] 48: Turntable

[0056] 50: Semiconductor substrate

[0057] 52: Carrier head

[0058] 54: Water supply nozzle

[0059] 56: Finisher

[0060] 100: Processed object

[0061] 200: Semiconductor devices

[0062] 300: Chemical Mechanical Polishing Device DETAILED DESCRIPTION

[0063] Hereinafter, preferred embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and includes various modifications that are implemented within the scope of the present invention.

[0064] In this specification, the numerical range described as "X to Y" is interpreted as including the numerical value X as the lower limit and the numerical value Y as the upper limit.

[0065] 1. Chemical mechanical polishing composition

[0066] A chemical mechanical polishing composition according to one embodiment of the present invention comprises: (A) silica particles comprising a functional group represented by the following general formula (1) (also referred to as "component (A)" in this specification), and (B) a silane compound (also referred to as "component (B)" in this specification).

[0067] -COO - M + ·····(1)

[0068] (M + represents a monovalent cation.)

[0069] Hereinafter, each component contained in the chemical mechanical polishing composition according to this embodiment will be described in detail.

[0070] 1.1.(A)Ingredients

[0071] The chemical mechanical polishing composition of this embodiment contains (A) silica particles having a functional group represented by the following general formula (1) as an abrasive component.

[0072] -COO - M + ·····(1)

[0073] (M + represents a monovalent cation.)

[0074] As a M + The monovalent cations represented by are not limited to these, for example, H + 、Li + 、Na + , K + NH4 + That is, the component (A) may also be referred to as "(A) silica particles comprising at least one functional group selected from the group consisting of carboxyl groups and salts thereof". Here, "carboxyl salts" refer to the silica particles prepared by Li + 、Na + , K + NH4 + A functional group obtained by replacing a hydrogen ion contained in a carboxyl group (-COOH) with a monovalent cation such as a cation. Component (A) comprises silica particles having a functional group represented by the general formula (1) covalently bonded to the surface thereof, and does not include a compound having a functional group represented by the general formula (1) physically or ionically adsorbed on the surface thereof.

[0075] The component (A) used in the present embodiment can be produced, for example, as follows.

[0076] First, prepare silica particles. Examples of silica particles include fumed silica and colloidal silica, but colloidal silica is preferred from the perspective of reducing polishing defects such as scratches. Colloidal silica can be prepared, for example, by the method described in Japanese Patent Laid-Open No. 2003-109921. By modifying the surface of such silica particles, component (A) that can be used in this embodiment can be produced. The following illustrates a method for modifying the surface of silica particles, but the present invention is not limited to any of the specific examples.

[0077] The surface modification of silica particles can be performed using the methods described in Japanese Patent Application Publication No. 2005-162533 or Japanese Patent Application Publication No. 2010-269985. For example, silica particles can be mixed with a carboxyl group-containing silane coupling agent (e.g., (3-triethoxysilyl)propyl succinic anhydride) and stirred thoroughly to covalently bond the carboxyl group-containing silane coupling agent to the surface of the silica particles. Further heating and hydrolysis can produce silica particles in which the carboxyl groups are covalently bonded.

[0078] The lower limit of the average particle size of the (A) component is preferably 15 nm, more preferably 30 nm. The upper limit of the average particle size of the (A) component is preferably 100 nm, more preferably 70 nm. If the average particle size of the (A) component is within the range, there is a situation in which a semiconductor substrate containing a conductive metal such as tungsten or cobalt can be ground at a practical grinding speed while suppressing the generation of grinding defects. The average particle size of the (A) component can be obtained by measuring the manufactured chemical mechanical polishing composition using a particle size measuring device using a dynamic light scattering method. As a particle size measuring device based on the dynamic light scattering method, nanoparticle analyzer "Delsa Nano (DelsaNano) S" manufactured by Beckman-Coulter (Beckman-Coulter) Company, "Zetasizer Nano (Zetasizer nano) zs" manufactured by Malvern (Malvern) Company, etc. can be cited. Furthermore, the average particle size measured using the dynamic light scattering method represents the average particle size of secondary particles formed by the aggregation of multiple primary particles.

[0079] When the pH of the chemical mechanical polishing composition is between 1 and 6, the zeta potential of component (A) is negative in the chemical mechanical polishing composition, preferably -10 mV or less. A negative potential of -10 mV or less can effectively prevent particle aggregation due to electrostatic repulsion between particles, and can selectively polish positively charged substrates during chemical mechanical polishing. Examples of zeta potential measuring devices include the "ELSZ-1" manufactured by Otsuka Electronics Co., Ltd. and the "Zetasizernano zs" manufactured by Malvern. The zeta potential of component (A) can be appropriately adjusted by increasing or decreasing the amount of the carboxyl-containing silane coupling agent added.

[0080] When the total mass of the chemical mechanical polishing composition is set to 100 mass%, the lower limit of the content of component (A) is preferably 0.1 mass%, more preferably 0.5 mass%, and particularly preferably 1 mass%. When the total mass of the chemical mechanical polishing composition is set to 100 mass%, the upper limit of the content of component (A) is preferably 10 mass%, more preferably 8 mass%, and particularly preferably 5 mass%. When the content of component (A) is within this range, it is possible to polish a semiconductor substrate containing a conductive metal such as tungsten or cobalt at a practical polishing rate while suppressing the occurrence of polishing defects.

[0081] 1.2.(B) Ingredients

[0082] The chemical mechanical polishing composition of this embodiment contains a silane compound (B). The inclusion of component (B) is believed to allow component (B) to adsorb onto the polished surface during the polishing step, acting as a catalyst for condensation of metals such as wiring metals exposed on the polished surface, thereby forming a protective film. This allows the polishing of semiconductor substrates containing conductive metals such as tungsten and cobalt at a practical polishing rate while suppressing the occurrence of polishing defects.

[0083] As the component (B), for example, silane compounds represented by the following general formula (2), general formula (3), and general formula (4) can be preferably used.

[0084] Si(OR 1 )4·····(2)

[0085] In formula (2), there are multiple R 1 Each independently represents a monovalent hydrocarbon group. The monovalent hydrocarbon group is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl, and tert-butyl. Examples of the aryl group having 6 to 12 carbon atoms include phenyl and naphthyl.

[0086] Specific examples of the silane compound represented by the general formula (2) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetraphenoxysilane.

[0087] SiR 2 m (OR 3 ) n (R 4 -NR 5 2) p ·····(3)

[0088] SiR 2 m (OR 3 ) n R 5 p ·····(4)

[0089] In formula (3) and formula (4), R 2 and R 3 Each independently represents a monovalent hydrocarbon group, R 5 Each independently represents a monovalent organic group having 1 to 10 carbon atoms, which may or may not contain a heteroatom, or a hydrogen atom, m is an integer of 0 to 2, n is an integer of 1 to 3, p is 1 or 2, and m+n+p=4. In formula (3), R 4 represents a divalent hydrocarbon group.

[0090] As R 2 and R 3 The monovalent hydrocarbon group is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl, and tert-butyl. Examples of the aryl group having 6 to 12 carbon atoms include phenyl and naphthyl.

[0091] As R 4 The divalent hydrocarbon group includes linear or branched divalent hydrocarbon groups having 1 to 10 carbon atoms. Among them, an alkanediyl group having 1 to 4 carbon atoms is preferred. Examples of the alkanediyl group having 1 to 4 carbon atoms include methylene, ethylene, propylene, isopropylene, butylene, and isobutylene.

[0092] As containing or not containing R 5The monovalent organic group having 1 to 10 carbon atoms and containing a heteroatom thereof may be a linear, branched, or cyclic hydrocarbon group having 1 to 10 carbon atoms. Among these, an alkyl group having 1 to 4 carbon atoms or a cycloalkylalkyl group having 5 to 9 carbon atoms is preferred. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a tert-butyl group. Examples of the cycloalkylalkyl group having 5 to 9 carbon atoms include a cyclobutylmethyl group, a cyclopentylmethyl group, a cyclohexylmethyl group, a cyclobutylethyl group, a cyclopentylethyl group, a cyclohexylethyl group, a cyclobutylpropyl group, a cyclopentylpropyl group, and a cyclohexylpropyl group.

[0093] Specific examples of the silane compound represented by the general formula (3) include 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

[0094] Specific examples of the silane compound represented by the general formula (4) include 3-trimethoxysilylpropylsuccinic anhydride, 3-triethoxysilylpropylsuccinic anhydride, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0095] These (B) components may be used alone or in combination of two or more.

[0096] When the total mass of the chemical mechanical polishing composition is set to 100 mass%, the lower limit of the content of component (B) is preferably 0.0001 mass%, more preferably 0.0005 mass%, and particularly preferably 0.001 mass%. When the total mass of the chemical mechanical polishing composition is set to 100 mass%, the upper limit of the content of component (B) is preferably 0.05 mass%, more preferably 0.03 mass%, further preferably 0.02 mass%, and particularly preferably 0.015 mass%. If the content of component (B) is within the above range, a protective film of appropriate thickness can be formed on the surface of a conductive metal such as tungsten or cobalt, thereby suppressing the occurrence of polishing defects and performing polishing at a practical polishing rate.

[0097] Liquid medium

[0098] The chemical mechanical polishing composition of this embodiment contains a liquid medium. Examples of the liquid medium include water, a mixture of water and an alcohol, and a mixture of water and a water-compatible organic solvent. Of these, water and a mixture of water and an alcohol are preferred, with water being more preferred. The water is not particularly limited, but pure water is preferred. The water content is not particularly limited, as long as it constitutes the remainder of the chemical mechanical polishing composition.

[0099] 1.4. Other additives

[0100] The chemical mechanical polishing composition of this embodiment may further contain additives such as an oxidizing agent, an organic acid, a surfactant, a water-soluble polymer, a corrosion inhibitor, and a pH adjuster as needed.

[0101] <Oxidant>

[0102] The chemical mechanical polishing composition of this embodiment may also contain an oxidizing agent. By containing the oxidizing agent, the metal such as tungsten or cobalt is oxidized to promote the complex reaction with the polishing liquid components, thereby forming a fragile modified layer on the polished surface, thereby sometimes increasing the polishing rate.

[0103] Examples of the oxidizing agent include ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, ceric ammonium nitrate, potassium hypochlorite, ozone, potassium periodate, and peracetic acid. Among these oxidizing agents, ammonium persulfate, potassium persulfate, and hydrogen peroxide are preferred in view of oxidizing power and ease of handling, with hydrogen peroxide being more preferred. These oxidizing agents may be used alone or in combination of two or more.

[0104] When the chemical mechanical polishing composition of this embodiment contains an oxidizing agent, the content of the oxidizing agent 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, based on 100% by mass of the total mass of the chemical mechanical polishing composition. Furthermore, since the oxidizing agent readily decomposes in the chemical mechanical polishing composition, it is preferably added immediately before the CMP polishing step.

[0105] <Organic Acid>

[0106] The chemical mechanical polishing composition of this embodiment may also contain an organic acid. The inclusion of an organic acid may coordinate with the polishing surface, thereby increasing the polishing rate and suppressing the precipitation of metal salts during polishing. Furthermore, the coordination of the organic acid with the polishing surface may reduce damage to the polishing surface caused by etching and corrosion.

[0107] Such organic acids are not particularly limited, and examples thereof 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, mesaconic acid, 2-glutaconedioic acid, itaconic acid, allylmalonic acid, isopropylidene succinic acid, 2,4-hexadienedioic acid, and acetylenedicarboxylic acid; aromatic carboxylic acids such as 1,2,4-tricarboxylic acid; amino acids such as glycine, alanine, asparagine, glutamine, lysine, arginine, tryptophan, histidine, aromatic amino acids, and heterocyclic amino acids, and salts thereof. These organic acids may be used alone or in combination of two or more.

[0108] When the chemical mechanical polishing composition of this embodiment contains an organic acid, the content of the organic acid is preferably 0.01 to 5 mass %, more preferably 0.03 to 1 mass %, and particularly preferably 0.1 to 0.5 mass %, based on the total mass of the chemical mechanical polishing composition as 100 mass %.

[0109] <Surfactant>

[0110] The chemical mechanical polishing composition of this embodiment may also contain a surfactant. The inclusion of a surfactant may 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.

[0111] The surfactant is not particularly limited, and examples thereof include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0112] Examples of anionic surfactants include carboxylates such as fatty acid soaps and alkyl ether carboxylates; sulfonates such as alkylbenzenesulfonates, alkylnaphthalenesulfonates, and α-olefinsulfonates; sulfates such as higher alcohol sulfate esters, alkyl ether sulfates, and polyoxyethylene alkylphenyl ether sulfates; and fluorine-containing surfactants such as perfluoroalkyl compounds. Examples of cationic surfactants include aliphatic amine salts and aliphatic ammonium salts. Examples of nonionic surfactants include triple bond-containing nonionic surfactants such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohol; and polyethylene glycol-type surfactants. These surfactants may be used alone or in combination of two or more.

[0113] When the chemical mechanical polishing composition of this embodiment contains a surfactant, the content of the surfactant is preferably 0.001 to 5 mass %, more preferably 0.001 to 3 mass %, and particularly preferably 0.01 to 1 mass %, based on the total mass of the chemical mechanical polishing composition as 100 mass %.

[0114] <Water-soluble polymer>

[0115] The chemical mechanical polishing composition of this embodiment may also contain a water-soluble polymer. The water-soluble polymer has the effect of adsorbing on the surface of the polished surface and reducing polishing friction. This effect can reduce the occurrence of polishing defects on the polished surface.

[0116] Examples of the water-soluble polymer include poly(meth)acrylamide, poly(meth)acrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, and copolymers of (meth)acrylic acid and maleic acid.

[0117] 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 the range, it is easy to adsorb on the polished surface of the wiring material, etc., and the polishing friction can be further reduced. As a result, the polishing defects of the polished surface can be more effectively reduced. Furthermore, the so-called "weight average molecular weight (Mw)" in this specification refers to the weight average molecular weight converted to polyethylene glycol measured by gel permeation chromatography (GPC).

[0118] When the chemical mechanical polishing composition of this embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.01 to 1 mass%, more preferably 0.03 to 0.5 mass%, based on 100 mass% of the total mass of the chemical mechanical polishing composition.

[0119] The content of the water-soluble polymer also depends on the weight-average molecular weight (Mw) of the water-soluble polymer, but is preferably adjusted so that the viscosity of the chemical mechanical polishing composition at 25°C is 0.5 mPa·s or more and less than 10 mPa·s. A chemical mechanical polishing composition with a viscosity at 25°C of 0.5 mPa·s or more and less than 10 mPa·s facilitates high-speed polishing of wiring materials, etc., and the appropriate viscosity allows for stable supply of the chemical mechanical polishing composition to the polishing cloth.

[0120] <Corrosion Inhibitor>

[0121] 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 salts thereof.

[0122] 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 100% by mass, the content of the corrosion inhibitor is preferably 1% by mass or less, more preferably 0.001% by mass to 0.1% by mass.

[0123] <pH adjuster>

[0124] The chemical mechanical polishing composition of the present embodiment may further contain a pH adjuster as needed. Examples of the pH adjuster include alkalis such as potassium hydroxide, ethylenediamine, monoethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), ammonia; inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and salts thereof. One or more of these can be used.

[0125] 1.5. pH

[0126] The pH of the chemical mechanical polishing composition of the present embodiment is not particularly limited, and is preferably 2 or more and 5 or less, particularly preferably 2 or more and 4 or less. If the pH is within the above range, the dispersibility of the component (A) in the chemical mechanical polishing composition is improved, and thus the storage stability of the chemical mechanical polishing composition becomes good, and thus it is preferred.

[0127] 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 an organic acid, a pH adjuster, etc.

[0128] In the present invention, pH refers to the hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, manufactured by Horiba, Ltd., tabletop pH meter) under the conditions of 25 °C and 1 atmosphere.

[0129] 1.6. Use

[0130] The chemical mechanical polishing composition of this embodiment is suitable as a polishing material for chemical mechanical polishing of semiconductor substrates composed of various materials constituting semiconductor devices. For example, the semiconductor substrate may contain, in addition to conductive metals such as tungsten and cobalt, insulating film materials such as silicon oxide films, silicon nitride films, and amorphous silicon, and barrier metal materials such as titanium, titanium nitride, and tantalum nitride.

[0131] The chemical mechanical polishing composition of this embodiment is particularly suitable for polishing objects such as semiconductor substrates provided with wiring layers containing tungsten. Specifically, an object including a silicon oxide film having a through-hole and a tungsten film provided on the silicon oxide film via a barrier metal film can be used. The chemical mechanical polishing composition of this embodiment not only enables high-speed and flat polishing of tungsten films, but also enables high-speed and flat polishing of surfaces where tungsten films coexist with insulating films such as silicon oxide films, while suppressing the occurrence of polishing defects.

[0132] 1.7. Preparation Method of Chemical Mechanical Polishing Composition

[0133] The chemical mechanical polishing composition of this embodiment can be prepared by dissolving or dispersing the components in a liquid medium such as water. The dissolution or dispersion method is not particularly limited; any method can be used as long as it allows for uniform dissolution or dispersion. Furthermore, there are no particular restrictions on the order and method of mixing the components.

[0134] Furthermore, the chemical mechanical polishing composition of this embodiment can be prepared as a concentrated stock solution and diluted with a liquid medium such as water before use.

[0135] 2. Chemical Mechanical Polishing

[0136] A polishing method according to one embodiment of the present invention includes the step of polishing a semiconductor substrate using the chemical mechanical polishing composition. A specific example of the chemical mechanical polishing method according to this embodiment will be described in detail below using drawings.

[0137] 2.1. Object to be processed

[0138] Figure 1 1 is a cross-sectional view schematically showing an object to be processed to which the chemical mechanical polishing method of this embodiment is preferably applied. The object to be processed 100 is formed by the following steps (1) to (4).

[0139] (1) First, Figure 1 As shown, a substrate 10 is prepared. The substrate 10 may also be composed of, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional elements such as transistors (not shown) may be formed on the substrate 10. Subsequently, a silicon oxide film 12 serving as an insulating film is formed on the substrate 10 using a thermal oxidation method.

[0140] (2) Next, the silicon oxide film 12 is patterned. Using the obtained pattern as a mask, through holes 14 are formed in the silicon oxide film 12 by photolithography.

[0141] (3) Then, a barrier metal film 16 is formed on the surface of the silicon oxide film 12 and the inner wall surface of the through hole 14 by sputtering or the like. Tungsten and silicon do not have good electrical contact, so the presence of the barrier metal film in between allows for good electrical contact. Examples of the barrier metal film 16 include titanium and / or titanium nitride.

[0142] (4) Then, a tungsten film 18 is deposited using a chemical vapor deposition (CVD) method.

[0143] Through the above steps, the object to be processed 100 is formed.

[0144] Chemical Mechanical Polishing

[0145] 2.2.1. First grinding step

[0146] Figure 2 : is a schematic cross-sectional view of the workpiece at the end of the first grinding step. Figure 2 As shown, the tungsten film 18 is polished using the chemical mechanical polishing composition until the barrier metal film 16 is exposed.

[0147] 2.2.2. Second grinding step

[0148] Figure 3 Schematically shows the cross-sectional view of the workpiece at the end of the second grinding step. Figure 3 As shown, the chemical mechanical polishing composition is used to polish the silicon oxide film 12, the barrier metal film 16, and the tungsten film 18. By performing the second polishing step, a next-generation semiconductor device 200 having excellent planarity of the polished surface can be manufactured.

[0149] Furthermore, as described above, the chemical mechanical polishing composition is suitable as a polishing material for chemical mechanical polishing of semiconductor substrates composed of various materials that constitute semiconductor devices. Therefore, the chemical mechanical polishing composition of the same composition can be used in the first and second polishing steps of the chemical mechanical polishing method of this embodiment, thereby increasing production line throughput.

[0150] 2.3. Chemical Mechanical Polishing Device

[0151] In the first grinding step and the second grinding step, for example, Figure 4 The grinding device 300 is shown. Figure 4 3D is a perspective view schematically showing a polishing apparatus 300. The first polishing step and the second polishing step are performed by supplying slurry (chemical mechanical polishing composition) 44 from a slurry supply nozzle 42 and rotating a turntable 48 to which a polishing cloth 46 is attached while abutting a carrier head 52 holding a semiconductor substrate 50. Figure 4 In FIG, the water supply nozzle 54 and the trimmer 56 are also shown.

[0152] The polishing load of the carrier head 52 can be selected within the range of 10 hPa to 980 hPa, preferably 30 hPa to 490 hPa. Furthermore, the rotational speed of the turntable 48 and the carrier 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 polishing composition) 44 supplied from the slurry supply nozzle 42 can be selected within the range of 10 mL / min to 1,000 mL / min, preferably 50 mL / min to 400 mL / min.

[0153] As commercially available polishing devices, for example, there are models "EPO-112" and "EPO-222" manufactured by EBARA Manufacturing Co., Ltd.; models "LGP-510" and "LGP-552" manufactured by Lapmaster SFT; models "Mirra" and "Reflexion" manufactured by Applied Materials; model "POLI-400L" manufactured by G&P TECHNOLOGY; model "Reflexion LK" manufactured by AMAT, etc.

[0154] 3. Examples

[0155] The present invention will be described below by way of examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0156] 3.1. Preparation of silica particle aqueous dispersion

[0157] Preparation of aqueous dispersion A

[0158] In capacity 2000cm 32000 g of PL-3 (manufactured by Fuso Chemical Industries, Ltd., 19.5% colloidal silica) was added to a flask and heated to 60°C. Then, 6.0 g of (3-triethoxysilyl)propyl succinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was heated at 60°C and allowed to react for 4 hours. After cooling, an aqueous dispersion A of carboxylic acid-modified silica particles was obtained.

[0159] 3.1.2. Preparation of aqueous dispersion B

[0160] A mixture of 1522.2 g of tetramethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 413.0 g of methanol was added dropwise over 55 minutes to a mixture of 787.9 g of pure water, 786.0 g of 25% aqueous ammonia (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 12,924 g of methanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), while maintaining the liquid temperature at 35°C, to obtain a hydrolyzed silica sol dispersion. The sol was concentrated to 2900 ml by heating at atmospheric pressure. The concentrated solution was further heated and distilled at atmospheric pressure, and pure water was added dropwise while maintaining the volume constant. The addition of pure water was terminated when the column top temperature reached 100°C and the pH was 8 or less, thereby obtaining a silica sol. A mixture of 19.0 g of methanol and 1.0 g of 3-aminopropyltrimethoxysilane was added dropwise over 10 minutes to 540 g of the prepared silica sol while maintaining the liquid temperature, followed by reflux at atmospheric pressure for 2 hours. Pure water was then added dropwise while maintaining a constant volume. The addition of pure water was terminated when the column top temperature reached 100°C to obtain an aqueous dispersion of amino-modified silica particles. The obtained aqueous dispersion was vacuum-dried at 150°C for 24 hours to obtain amino-modified silica particles.

[0161] The resulting amino-modified silica particles were dried at 70°C for 12 hours. In a nitrogen-purged three-necked flask, 1.4 g of malonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was weighed and 20.0 ml of N-methyl-2-pyrrolidone (NMP, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and stirred until the malonic acid was completely dissolved. 2.0 g of amino-modified silica particles were added to the reaction solution and stirred for 1 hour. Subsequently, 6.2 g of diphenyl (2,3-dihydro-2-thioketo-3-benzoxazolyl)phosphonate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.4 ml of triethylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and stirred at room temperature for 24 hours. The reaction solution was allowed to stand overnight to allow the particles to settle. After discarding the supernatant, the particles were washed several times with NMP to obtain carboxylic acid-modified silica particles. The recovered particles were vacuum-dried at 100°C for 12 hours to remove the solvent. An appropriate amount of pure water was added to obtain a 20% aqueous dispersion B of carboxylic acid-modified silica particles.

[0162] Preparation of aqueous dispersion C

[0163] Amino-modified silica particles were obtained using the same method as described in "3.1.2. Preparation of Aqueous Dispersion B." The obtained amino-modified silica particles were vacuum-dried at 70°C for 12 hours. 1.4 g of citric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was measured in a three-necked flask previously purged with nitrogen, and 20.0 ml of N-methyl-2-pyrrolidone (NMP) was added and stirred until the citric acid was completely dissolved. 2.0 g of amino-modified silica particles were added to the reaction solution and stirred for 1 hour. Then, 5.7 g of diphenyl 2,3-dihydro-2-thioxo-3-benzoxazolylphosphonate and 1.3 ml of triethylamine were added and stirred at room temperature for 24 hours. The reaction solution was allowed to stand overnight to allow the particles to settle. After discarding the supernatant, the particles were washed several times with NMP to obtain carboxylic acid-modified silica particles. The recovered particles were vacuum-dried at 100°C for 12 hours to remove the solvent. An appropriate amount of pure water was added to obtain an aqueous dispersion C of 20% carboxylic acid-modified silica particles.

[0164] Preparation of aqueous dispersion D

[0165] In capacity 2000cm 3 2000 g of PL-3 (manufactured by Fuso Chemical Industries, Ltd., 19.5% colloidal silica) was added to a flask and heated to 60°C. 12.0 g of (3-triethoxysilyl)propyl succinic anhydride was then added as a silane coupling agent. The mixture was heated at 60°C and the reaction continued for 4 hours. After cooling, an aqueous dispersion D of carboxylic acid-modified silica particles was obtained.

[0166] Preparation of aqueous dispersion E

[0167] In capacity 2000cm 3 2000 g of PL-3 (manufactured by Fuso Chemical Industries, Ltd., 19.5% colloidal silica) was added to a flask and heated to 60°C. 18.0 g of (3-triethoxysilyl)propyl succinic anhydride was then added as a silane coupling agent. The mixture was heated at 60°C and the reaction continued for 4 hours. After cooling, an aqueous dispersion E of carboxylic acid-modified silica particles was obtained.

[0168] 3.1.6. Preparation of aqueous dispersion F

[0169] Capacity 2000cm 370 g of 25% by mass ammonia water, 40 g of ion-exchanged water, 175 g of ethanol, and 21 g of tetraethoxysilane were placed in a flask and heated to 60°C while stirring at 180 rpm. Stirring was maintained at 60°C for 1 hour, followed by cooling to obtain a colloidal silica / alcohol dispersion. Subsequently, the alcohol content was removed by adding ion-exchanged water to the dispersion using an evaporator at 80°C, repeatedly removing the alcohol component several times to prepare a silica dispersion with a solids concentration of 15%.

[0170] 5 g of acetic acid was added to 50 g of ion-exchanged water, and 5 g of a mercapto group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBE 803") was gradually added dropwise while stirring. After 30 minutes, 1000 g of a previously prepared silica dispersion was added, and stirring was continued for another hour. Then, 200 g of 31% aqueous hydrogen peroxide was added, and the mixture was left to stand at room temperature for 48 hours, thereby obtaining an aqueous dispersion F containing silica particles having sulfonic groups.

[0171] 3.1.7. Preparation of aqueous dispersion G

[0172] A mixture of 1522.2 g of tetramethoxysilane and 413.0 g of methanol was added dropwise over 55 minutes to a mixture of 787.9 g of pure water, 786.0 g of 26% aqueous ammonia, and 12,924 g of methanol while maintaining the liquid temperature at 35°C. The mixture was then concentrated to 2,900 ml by heating under normal pressure. The concentrated solution was further heated and distilled under normal pressure, while pure water was added dropwise while maintaining the volume constant. The addition of pure water was terminated when the column top temperature reached 100°C and the pH was 8 or less, thereby preparing a silica dispersion.

[0173] A mixture of 19.0 g of methanol and 1.0 g of 3-aminopropyltriethoxysilane was added dropwise to 540 g of the prepared silica dispersion over 10 minutes while maintaining the liquid temperature. The mixture was then refluxed at normal pressure for 2 hours. Pure water was then added dropwise while maintaining the volume constant. The addition of pure water was terminated when the tower top temperature reached 100°C, yielding aqueous dispersion G containing silica particles having amino groups.

[0174] 3.2. Preparation of Chemical Mechanical Polishing Composition

[0175] Hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 30% aqueous solution) was used as an oxidizing agent. The components were added to a polyethylene container to give the compositions shown in Tables 1 to 3. Potassium hydroxide was added as needed to adjust the pH to the values shown in Tables 1 to 3. The chemical mechanical polishing compositions of Examples and Comparative Examples were prepared by adding pure water so that the total amount of all components would be 100 parts by mass.

[0176] Evaluation methods

[0177] 3.3.1. Grinding speed test

[0178] Using the chemical mechanical polishing composition obtained above, a chemical mechanical polishing test was performed for 60 seconds under the following polishing conditions using a 12-inch diameter wafer with a 300nm CVD-W film or a 12-inch diameter wafer with a 300nm p-TEOS film (silicon oxide film) as the polishing object.

[0179] <Grinding Conditions>

[0180] Grinding device: Made by AMAT, model "Reflexion LK"

[0181] Polishing pad: Fujibo Holdings Co., Ltd., "Multi-hard polyurethane pad; H800-type1(3-1S)775"

[0182] Chemical mechanical polishing composition supply rate: 300 mL / min

[0183] Platen speed: 100rpm

[0184] Head speed: 90rpm

[0185] Head pressing pressure: 2.5psi

[0186]

[0187] The thickness of the tungsten film was measured using a resistivity meter (model "OmniMap RS100" manufactured by KLA-Tencor) using a DC four-probe method. The sheet resistance value and the volume resistivity of tungsten were calculated using the following formula.

[0188] ·

[0189] The evaluation criteria for the polishing rate test are as follows: Tables 1 to 3 show the polishing rate results for the tungsten film and the polishing rate results for the silicon oxide film, along with their evaluation results.

[0190] (Evaluation Criteria)

[0191] ·“A”... When the tungsten grinding speed is / min or more and the p-TEOS polishing speed is When the polishing speed is 0.05 or more per minute, both polishing speeds are sufficiently high, and therefore the polishing speed balance with the polishing speed of other material films can be easily secured in actual polishing of semiconductor substrates and is practical, so it is judged as good "A".

[0192] · "B" ... when the tungsten grinding speed is less than / min or p-TEOS grinding speed is less than / min, since the polishing rate of both or one of them is low, it is difficult to be practical and is judged as poor "B".

[0193] 3.3.2. Defect evaluation

[0194] A wafer with a p-TEOS film and a diameter of 12 inches as an object to be polished was polished for 2 minutes under the following conditions.

[0195] <Grinding Conditions>

[0196] Grinding device: Made by AMAT, model "Reflexion LK"

[0197] Polishing pad: Fujibo Holdings Co., Ltd., "Multi-hard polyurethane pad; H800-type1(3-1S)775"

[0198] Chemical mechanical polishing composition supply rate: 300 mL / min

[0199] Platen speed: 100rpm

[0200] Head speed: 90rpm

[0201] Head pressing pressure: 2.5psi

[0202] The polished p-TEOS film-bearing wafers were counted using a defect inspection system (Surfscan SP1, manufactured by KLA-Tencor) to determine the total number of defects larger than 90 nm. The evaluation criteria were as follows. The total number of defects per wafer and the evaluation results are shown in Tables 1 to 3.

[0203] (Evaluation Criteria)

[0204] "A" ... A case where the total number of defects per wafer is less than 500 is judged as good "A".

[0205] "B" ... A wafer with a total of 500 or more defects per wafer is judged as defective "B".

[0206] 3.4. Evaluation results

[0207] Tables 1 to 3 below show the compositions of the chemical mechanical polishing compositions of Examples and Comparative Examples and the evaluation results.

[0208]

[0209]

[0210]

[0211] The following commercial products or reagents were used for each component in Tables 1 to 3. The content of the abrasive particles in Tables 1 to 3 indicates the solid content concentration of each aqueous dispersion.

[0212] <Abrasive Grains>

[0213] Aqueous dispersions A to G: Aqueous dispersions A to G of the silica particles prepared above

[0214] PL-3: Made by Fuso Chemical Industry Co., Ltd., trade name "PL-3," colloidal silica, average particle size 70 nm

[0215] <Silane Compound>

[0216] 3-Triethoxysilylpropyl succinic anhydride: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "[(3-Triethoxysilyl)propyl]succinic anhydride"

[0217] 3-Mercaptopropyltrimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "(3-Mercaptopropyl)trimethoxysilane"

[0218] 3-Aminopropyltrimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "3-Aminopropyltrimethoxysilane"

[0219] <Organic Acid>

[0220] Citric acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Citric Acid"

[0221] Maleic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Maleic Acid"

[0222] · Malonic Acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Malonic Acid"

[0223] · Apple Acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "DL-Apple Acid"

[0224] · Histidine: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "L-Histidine"

[0225] · Arginine: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "L-(+)-Arginine"

[0226] <Water-soluble polymer>

[0227] · Polyacrylic acid: Manufactured by Toagosei Co., Ltd., product name "Jurymer AC-10L", MW = 20,000 - 30,000

[0228] <pH adjuster>

[0229] · Monoethanolamine: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "2-Aminoethanol"

[0230] · TEAH: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Tetraethylammonium Hydroxide (10% aqueous solution)", Tetraethylammonium Hydroxide

[0231] When using the chemical mechanical polishing compositions of Examples 1 to 25, tungsten films and p-TEOS films can be polished at a practical polishing rate, and the occurrence of surface defects on the polished p-TEOS films can be reduced.

[0232] The present invention is not limited to the above-described embodiments and can be variously modified. For example, the present invention includes structures that are substantially the same as the structures described in the embodiments (for example, structures having the same functions, methods, and results, or structures having the same purposes and effects). In addition, the present invention includes structures obtained by replacing non-essential parts of the structures described in the embodiments. In addition, the present invention includes structures that exhibit the same effects as the structures described in the embodiments or structures that can achieve the same purposes. In addition, the present invention includes structures obtained by adding existing technologies to the structures described in the embodiments.

Claims

1. A chemical mechanical polishing composition comprising: Component (A): silica particles containing a functional group represented by the following general formula (1); and (B) Component: Silane compound, -COO － M + (1) M + represents a monovalent cation, When the total mass of the chemical mechanical polishing composition is 100 mass %, the content of the component (A) is 0.1 mass % to 10 mass %, and the content of the component (B) is 0.0001 mass % to 0.02 mass %. 2 . The chemical mechanical polishing composition according to claim 1 , wherein the component (A) comprises silica particles having functional groups represented by the general formula (1) fixed to the surface thereof via covalent bonds.

3. The chemical mechanical polishing composition according to claim 1, wherein the component (B) is one or more compounds selected from the group consisting of compounds represented by the following general formula (2), general formula (3), and general formula (4). Si(OR 1 )4 (2) SiR 2 m (OR 3 ) n (R 4 -NR 5 2) p (3) SiR 2 m (OR 3 ) n R 5 p (4) In formula (2), there are multiple R 1 Each independently represents a monovalent hydrocarbon group; in formula (3), R 4 represents a divalent hydrocarbon group; in formula (3) and formula (4), R 2 and R 3 Each independently represents a monovalent hydrocarbon group, R 5 Each independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a heteroatom or a hydrogen atom, m is an integer of 0 to 2, n is an integer of 1 to 3, p is 1 or 2, and m+n+p=4.

4. The chemical mechanical polishing composition according to claim 1, wherein the component (B) is one or more selected from the group consisting of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraphenoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, 3-triethoxysilylpropylsuccinic anhydride, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane. The chemical mechanical polishing composition according to claim 1 , further comprising an organic acid. The chemical mechanical polishing composition according to claim 1 , further comprising an oxidizing agent.

7. The chemical mechanical polishing composition according to claim 1, wherein The pH is 2 or higher and 5 or lower. 8 . A chemical mechanical polishing method comprising the step of polishing a semiconductor substrate using the chemical mechanical polishing composition according to claim 1 .

9. The chemical mechanical polishing method according to claim 8, wherein: The semiconductor substrate includes a portion containing at least one selected from the group consisting of silicon oxide and tungsten.

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