TW202128942A - Composition for chemical mechanical polishing and method of chemical mechanical polishing wherein the composition includes silica particles modified with a compound having two or more amine groups and a liquid medium - Google Patents

Abstract

The present invention provides a composition for chemical mechanical polishing and a method of chemical mechanical polishing, which can perform high-speed and flat polishing on a to-be-polished surface where conductive metals such as tungsten and cobalt and an insulating film such as silicon oxide film coexist. The present invention can reduce surface defects after polishing. The composition for chemical mechanical polishing of the present invention contains: (A) silica particles modified with a compound having two or more amine groups and (B) a liquid medium, when the total mass of the composition for chemical mechanical polishing is set to be 100% by mass, the content of the component (A) is 0.1% by mass or more and 10% by mass or less.

Description

Composition for chemical mechanical polishing and chemical mechanical polishing method

The invention relates to a chemical mechanical polishing composition and a chemical polishing method.

The miniaturization of wiring layers including wiring, plugs, etc., formed in semiconductor devices is progressing. Along with this, a method of planarizing the wiring layer using chemical mechanical polishing (hereinafter also referred to as “CMP (Chemical Mechanical Polishing)”) is used. The ultimate goal of this CMP is to flatten the polished surface after polishing to obtain a defect-free and corrosion-free surface. Therefore, the chemical mechanical polishing composition used in CMP is evaluated based on characteristics such as the material removal rate, the surface defect rate after polishing, and the prevention of metal corrosion after polishing.

In recent years, with the further miniaturization of wiring layers, tungsten (W) or cobalt (Co) has begun to be used as conductor metals. Therefore, it is required to efficiently remove the tungsten or cobalt of the remaining build-up layer by CMP, and to suppress the corrosion of the tungsten or cobalt, and to form a good surface condition. Regarding such chemical mechanical polishing of tungsten or cobalt, a chemical mechanical polishing composition containing various additives has been proposed (for example, refer to Patent Document 1 and Patent Document 2). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2017-514295 [Patent Document 2] Japanese Patent Laid-Open No. 2016-030831

[The problem to be solved by the invention] With the spread of semiconductor wafers containing conductive metals such as tungsten or cobalt, it is required that the surface to be polished where conductive metals such as tungsten and cobalt and insulating films such as silicon oxide film coexist can be polished at high speed and flat, and to reduce polishing. Chemical mechanical polishing composition and chemical mechanical polishing method for subsequent surface defects.

In particular, on the surface to be polished where the conductor metal and the insulating film coexist, if the polishing rate of the conductor metal is faster than the polishing rate of the insulating film, there is a tendency for the conductor metal part to be shaved into a dish-like shape. The problem of surface defects called dishing requires a solution to this problem. [Means to solve the problem]

One aspect of the chemical mechanical polishing composition of the present invention includes: (A) Silica particles modified with compounds having more than two amine groups; and (B) Liquid medium.

In one form of the chemical mechanical polishing composition, it may be: The zeta potential of the component (A) in the chemical mechanical polishing composition is +10 mV or more.

In any form of the chemical mechanical polishing composition, it may be: When the total mass of the chemical mechanical polishing composition is 100% by mass, The content of the component (A) is 0.1% by mass or more and 10% by mass or less.

In any form of the chemical mechanical polishing composition, May contain acidic compounds.

In any form of the chemical mechanical polishing composition, May contain oxidizing agent.

In any form of the chemical mechanical polishing composition, it may be: The pH is 2 or more and 5 or less.

One aspect of the chemical mechanical polishing method of the present invention includes: The step of polishing a semiconductor substrate using the chemical mechanical polishing composition of any one of the above forms.

In one form of the chemical mechanical polishing method, it may be: The semiconductor substrate includes a portion containing at least one selected from the group consisting of silicon oxide and tungsten. [Effects of the invention]

According to the chemical mechanical polishing composition of the present invention, the polished surface on which conductive metals such as tungsten and cobalt and an insulating film such as silicon oxide film coexist can be polished at high speed and flat, and surface defects after polishing can be reduced.

Hereinafter, suitable embodiments of the present invention will be described in detail. In addition, the present invention is not limited to the following embodiments, and includes various modified examples implemented within a scope that does not change the gist of the present invention.

In this manual, the numerical range described in "～" is used to include the numerical values described before and after "～" as the meaning of the lower limit and the upper limit.

1. Composition for chemical mechanical polishing The chemical mechanical polishing composition of one embodiment of the present invention includes: (A) silica particles modified with a compound having two or more amine groups (in this specification, also referred to as "(A) component"), and (B) Liquid medium (also referred to as "(B) component" in this manual). Hereinafter, each component contained in the chemical mechanical polishing composition of the present embodiment will be described in detail.

1.1. (A) component The chemical mechanical polishing composition of the present embodiment contains (A) silica particles modified with a compound having two or more amine groups as an abrasive component. When the pH of the chemical mechanical polishing composition is 1 or more and 6 or less, the (A) component has a relatively large positive charge because it has an amino group. Therefore, insulating films such as silicon oxide films whose surface potential changes from 0 to negative in the region where the pH is 1 or more and 6 or less can be polished at a higher speed. Thereby, the surface to be polished on which the insulating film and the conductive metal coexist can be polished at high speed and flat, and the occurrence of dents in the conductive metal portion can be suppressed.

Furthermore, the more the number of amine groups in the "compounds with more than two amine groups" that modifies the silica particles, the greater the absolute value of the zeta potential of component (A), and the polishing speed of the insulating film and the conductive metal The difference in polishing speed tends to become smaller. As a result, the flatness of the polished surface where the insulating film and the conductor metal coexist may improve.

(A) The component is a silicon dioxide particle having two or more compounds with at least one functional group selected from the group consisting of amine groups and their salts fixed on the surface via covalent bonds, and is not included on the surface Those with the compound adsorbed physically or ionic.

As the compound having two or more amine groups, for example, a compound represented by the following general formula (1) can be preferably used.

SiR ¹ _m (OR ² ) _n (R ³ -NR ⁴ ₂ ) _p・・・・・（1）

In the above formula (1), R ¹ and R ² each independently represent 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 linear or branched alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, and 1-methyl. Propyl, tertiary butyl. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group and a naphthyl group.

In the above formula (1), R ³ represents a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include a linear or branched divalent hydrocarbon group having 1 to 10 carbon atoms. Among them, an alkanediyl group having 1 to 3 carbon atoms is preferred. Examples of the linear or branched divalent hydrocarbon group having 1 to 10 carbon atoms include methylene, ethylene, propylene, isopropyl, ethylene, and isobutyl.

In the above formula (1), R ⁴ each independently represents a C 1-10 monovalent organic group or a hydrogen atom that may contain a hetero atom. Examples of the monovalent organic group having 1 to 10 carbon atoms that may contain a hetero atom include a linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. In addition, when R ⁴ is an alkyl group, an alkenyl group, or a phenyl group, part of its hydrogen atoms may be substituted with an amino group, a sulfo group, a halogen atom, or the like.

In the formula (1), m is an integer of 0 to 2, n is an integer of 0 to 2, p is an integer of 2 to 4, and m+n+p=4.

Specific examples of compounds having two or more amino groups include (aminoethyl)aminopropyltrimethoxysilane, N-(3-trimethoxysilylpropyl)ethylenediamine, N- (3-Triethoxysilylpropyl)ethylenediamine, N-(3-tripropoxysilylpropyl)ethylenediamine, N-[2-[3-(triethoxysilyl) Propylamino]ethyl]ethylenediamine, N-[2-[3-(tripropoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(tri Isopropoxysilyl)propylamino]ethyl]ethylenediamine, N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, etc.

The (A) component used in this embodiment can be manufactured as follows, for example. First, prepare silica particles. Examples of the silica particles include fumed silica, colloidal silica, etc. However, from the viewpoint of reducing polishing defects such as scratches, colloidal silica is preferred. The colloidal silica can be manufactured by, for example, a method described in Japanese Patent Laid-Open No. 2003-109921 or the like. By modifying the surface of such silica particles with a compound having two or more amine groups, the component (A) that can be used in this embodiment can be produced. The method of modifying the surface of silica particles with a compound having two or more amine groups is exemplified below, but the present invention is not limited to this specific example at all.

As the surface modification of the silica particles, the method described in Japanese Patent Laid-Open No. 2005-162533 or Japanese Patent Laid-Open No. 2010-269985 can be applied. For example, by mixing silica particles with a silane coupling agent having two or more amine groups (for example, (aminoethyl)aminopropyltrimethoxysilane), and stirring sufficiently, the two The silane coupling agent with more than one amine group is covalently bonded to the surface of the silica particles. By further heating and hydrolyzing, silicon dioxide particles in which two or more amine groups are fixed via covalent bonds can be obtained.

(A) The lower limit of the average particle diameter of the component is preferably 15 nm, more preferably 30 nm. (A) The upper limit of the average particle diameter of the component is preferably 100 nm, more preferably 70 nm. If the average particle size of the component (A) is within the above range, it is possible to suppress the generation of polishing defects, and at the same time, it is possible to achieve a practical polishing rate for the polished surface where conductive metals such as tungsten and cobalt and insulating films such as silicon oxide film coexist. In the case of grinding. (A) The average particle size of the component can be obtained by measuring the manufactured chemical mechanical polishing composition with a particle size measuring device using a dynamic light scattering method. As a particle size measuring device based on the dynamic light scattering method, the nanoparticle analyzer "Delsa Nano S" manufactured by Beckman Coulter and the manufactured by Malvern Co., Ltd. can be cited. "Zetasizer nano (Zetasizer nano) zs" and so on. In addition, the average particle diameter measured using a dynamic light scattering method means the average particle diameter of the secondary particle formed by aggregating a plurality of primary particles.

When the pH of the chemical mechanical polishing composition is 1 or more and 6 or less, the zeta potential of component (A) is a positive potential in the chemical mechanical polishing composition, and the lower limit of the positive potential is preferably +10 mV, more preferably +15 mV. In addition, the upper limit of the positive potential is preferably +40 mV, more preferably +35 mV. If the zeta potential of component (A) is within the above range, the electrostatic repulsion between the particles can sometimes effectively prevent the particles from agglomerating. At the same time, it is possible to grind negatively charged silicon from 0 at high speed during chemical mechanical polishing. Insulating film such as oxide film. Furthermore, as the zeta potential measuring device, "ELSZ-1" manufactured by Otsuka Electronics Co., Ltd., "Zetasizer nano zs" manufactured by Malvern Corporation, and the like can be cited. The zeta potential of the component (A) can be appropriately adjusted by increasing or decreasing the addition amount of the silane coupling agent having two or more amine groups.

When the total mass of the chemical mechanical polishing composition is 100% by mass, the lower limit of the content of the component (A) is preferably 0.1% by mass, more preferably 0.5% by mass, and particularly preferably 1% by mass. When the total mass of the chemical mechanical polishing composition is 100% by mass, the upper limit of the content of the component (A) is preferably 10% by mass, more preferably 8% by mass, and particularly preferably 5% by mass. If the content of the component (A) is within the above range, it is possible to perform polishing on the polished surface where a conductive metal such as tungsten or cobalt and an insulating film such as a silicon oxide film coexist at a practical polishing rate while suppressing the occurrence of polishing defects. Grinding situation.

1.2. (B) Liquid medium The chemical mechanical polishing composition of this embodiment contains (B) a liquid medium. The (B) component includes a mixed medium of water, water, and alcohol, a mixed medium containing water and an organic solvent having compatibility with water, and the like. Among these, it is preferable to use water, a mixed medium of water and alcohol, and it is more preferable to use water. The water is not particularly limited, but pure water is preferred. Water may be prepared as the remainder of the constituent materials of the chemical mechanical polishing composition, and the content of water is not particularly limited.

1.3. Other additives The chemical mechanical polishing composition of the present embodiment may further contain additives such as an oxidizing agent, an acidic compound, a surfactant, a water-soluble polymer, an anticorrosive agent, and a pH adjuster, if necessary. Each additive will be described below.

＜Oxidant＞ The chemical mechanical polishing composition of this embodiment may contain an oxidizing agent. By containing an oxidizing agent, a conductive metal such as tungsten or cobalt is oxidized to promote a complex reaction with the components of the polishing liquid, so that a fragile modified layer can be formed on the surface to be polished, which may increase the polishing rate.

Examples of the oxidizing agent include ammonium persulfate, potassium persulfate, hydrogen peroxide, iron nitrate, cerium ammonium nitrate, potassium hypochlorite, ozone, potassium periodate, peracetic acid, and the like. Among these oxidants, in consideration of oxidizing power and ease of handling, ammonium persulfate, potassium persulfate, and hydrogen peroxide are preferred, and hydrogen peroxide is more preferred. These oxidants may be used alone or in combination of two or more.

In the case where the chemical mechanical polishing composition of the present embodiment contains an oxidizing agent, when the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the oxidizing agent is preferably 0.1% to 5% by mass, more preferably 0.3% by mass to 4% by mass, particularly preferably 0.5% by mass to 3% by mass. Furthermore, the oxidizing agent is easily decomposed in the chemical mechanical polishing composition, so it is desirable to add it immediately before the CMP polishing step.

＜Acid compounds＞ The composition for chemical mechanical polishing of this embodiment may contain an acidic compound. By containing the acidic compound, the acidic compound may be coordinated on the surface to be polished, and the polishing speed may be increased, and at the same time, the precipitation of the metal salt during polishing may be suppressed. In addition, when the acidic compound is located on the surface to be polished, damages caused by etching and corrosion on the surface to be polished may be reduced.

Examples of such acidic compounds include organic acids 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; acrylic acid, methacrylic acid, crotonic acid, 2-butenoic acid, 2 -Methyl-3-butenoic acid, 2-hexenoic acid, 3-methyl-2-hexenoic acid and other unsaturated monocarboxylic acids; maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2 -Unsaturated dicarboxylic acids such as glutenedioic acid, itaconic acid, allylmalonic acid, isopropylidene succinic acid, 2,4-hexadienedioic acid, and acetylene dicarboxylic acid; 1,2,4 -Aromatic carboxylic acids such as trimellitic acid and their salts. As an inorganic acid, phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and these salts are mentioned, for example. These acidic compounds may be used alone or in combination of two or more.

In the case where the chemical mechanical polishing composition of the present embodiment contains an acidic compound, when the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the acidic compound is preferably 0.001% to 5% by mass, and more It is preferably 0.005% by mass to 1% by mass, particularly preferably 0.01% by mass to 0.5% by mass.

＜Surface active agent＞ The composition for chemical mechanical polishing of this embodiment may contain a surfactant. By containing a surfactant, there are cases where appropriate viscosity can be imparted to the composition for chemical mechanical polishing. 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.

The surfactant is not particularly limited, and examples include anionic surfactants, cationic surfactants, and nonionic surfactants.

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, polyoxyethylene alkylphenyl ether sulfates; fluorine-containing surfactants such as perfluoroalkyl compounds, etc. As a cationic surfactant, aliphatic amine salt, aliphatic ammonium salt, etc. are mentioned, for example. Examples of nonionic surfactants include nonionic surfactants having triple bonds such as acetylene glycol, acetylene glycol ethylene oxide adduct, and acetylene alcohol; polyethylene glycol type surfactants. These surfactants may be used alone or in combination of two or more.

When the chemical mechanical polishing composition of the present embodiment contains a surfactant, when the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the surfactant is preferably 0.001% by mass to 5% by mass , More preferably 0.003 mass% to 3 mass%, particularly preferably 0.005 mass% to 1 mass%.

＜Water-soluble polymer＞ The chemical mechanical polishing composition of this embodiment may contain a water-soluble polymer. The water-soluble polymer has the effect of being adsorbed on the surface of the surface to be polished to reduce the abrasive friction. With this effect, there are cases where the occurrence of polishing defects on the surface to be polished can be reduced.

Examples of water-soluble polymers include polyethyleneimine, poly(meth)acrylamide, poly(meth)acrylamide, poly(meth)acrylic acid, polyvinyl alcohol, polyvinylpyrrolidone, and hydroxyethyl Cellulose, carboxymethyl cellulose, copolymers of (meth)acrylic acid and maleic acid, etc.

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 above range, it may be easily adsorbed on the polished surface of the wiring material or the like, and polishing friction may be further reduced. As a result, it is possible to more effectively reduce the occurrence of polishing defects on the surface to be polished. In addition, the "weight average molecular weight (Mw)" in this specification refers to the weight average molecular weight in terms of polyethylene glycol measured by Gel Permeation Chromatography (GPC).

When the chemical mechanical polishing composition of the present embodiment contains a water-soluble polymer, when the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the water-soluble polymer is preferably 0.01% by mass to 1 % By mass, more preferably 0.03% by mass to 0.5% by mass.

Furthermore, the content of the water-soluble polymer also depends on the weight-average molecular weight (Mw) of the water-soluble polymer, but it 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. When the chemical mechanical polishing composition has a viscosity of 0.5 mPa·s or more and less than 10 mPa·s at 25°C, it is easy to polish wiring materials, etc. at high speed, and the viscosity is appropriate, so the chemical can be stably supplied to the polishing cloth. Composition for mechanical polishing.

＜Corrosion inhibitor＞ The chemical mechanical polishing composition of this embodiment may contain an anticorrosive agent. As the corrosion inhibitor, for example, benzotriazole and its derivatives can be cited. Here, the benzotriazole derivative refers to a substance obtained by substituting one or two or more hydrogen atoms of benzotriazole with, for example, a carboxyl group, a methyl group, an amino group, a hydroxyl group, or the like. Specific examples of benzotriazole derivatives include 4-carboxybenzotriazole, 7-carboxybenzotriazole, butyl benzotriazole, 1-hydroxymethylbenzotriazole, 1-hydroxybenzene And triazoles and their salts.

In the case where the chemical mechanical polishing composition of the present embodiment contains an anticorrosive agent, when the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the anticorrosive agent is preferably 1% by mass or less, more preferably 0.001 Mass%～0.1% by mass.

＜pH adjuster＞ The composition for chemical mechanical polishing of this embodiment may further contain a pH adjuster as needed. Examples of pH adjusters include alkalis such as potassium hydroxide, ethylenediamine, monoethanolamine, tetramethyl ammonium hydroxide (TMAH), tetraethyl ammonium hydroxide (TEAH), and ammonia. One or more of these can be used.

1.5.pH The pH of the chemical mechanical polishing composition of the present embodiment is not particularly limited, but is preferably 2 or more and 5 or less, and more preferably 2 or more and 4 or less. If the pH is in the above range, the dispersibility of the component (A) in the chemical mechanical polishing composition is improved, and the storage stability of the chemical mechanical polishing composition becomes good, which is preferable.

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

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

1.6. Purpose The chemical mechanical polishing composition of the present embodiment is suitable as a polishing material for chemical mechanical polishing of a semiconductor substrate having a plurality of materials constituting a semiconductor device. For example, in addition to conductive metals such as tungsten or cobalt, the semiconductor substrate may also include insulating film materials such as silicon oxide film, silicon nitride film, and amorphous silicon, and barrier metal materials such as titanium, titanium nitride, and tantalum nitride.

A particularly suitable polishing target of the chemical mechanical polishing composition of the present embodiment is a processed object such as a semiconductor substrate provided with a wiring layer containing tungsten. Specifically, the treatment object includes a silicon oxide film having through holes and a tungsten film provided on the silicon oxide film via a barrier metal film. By using the chemical mechanical polishing composition of this embodiment, not only the tungsten film can be polished at high speed and flat, but also the polished surface where the tungsten film and the insulating film such as silicon oxide film coexist can be suppressed while suppressing the occurrence of polishing defects. Perform high-speed and flat polishing.

1.7. Preparation method of chemical mechanical polishing composition The chemical mechanical polishing composition of the present embodiment can be prepared by dissolving or dispersing the respective components in a liquid medium such as water. The method of dissolution or dispersion is not particularly limited, and any method can be applied as long as it can be uniformly dissolved or dispersed. In addition, the mixing order and mixing method of the components are not particularly limited.

In addition, the chemical mechanical polishing composition of the present embodiment may be prepared as a concentrated stock solution, and diluted with a liquid medium such as water when used.

2. Chemical mechanical polishing method A polishing method according to an embodiment of the present invention includes a step of polishing a semiconductor substrate using the chemical mechanical polishing composition. Hereinafter, a specific example of the chemical mechanical polishing method of the present embodiment will be described in detail using drawings.

2.1. The processed body FIG. 1 is a cross-sectional view schematically showing a to-be-processed object suitable for using the chemical mechanical polishing method of this embodiment. The processed body 100 is formed by going through the following steps (1) to (4).

(1) First, as shown in Fig. 1, a base 10 is prepared. The base 10 may also be composed of, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional elements such as a transistor (not shown) can be formed on the base 10. Then, on the base 10, a silicon oxide film 12 as an insulating film is formed using a thermal oxidation method.

(2) Next, the silicon oxide film 12 is patterned. The obtained pattern is a mask, and a through hole 14 is formed on the silicon oxide film 12 by photolithography.

(3) Next, the 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. The electrical contact between tungsten and silicon is not very good, so a good electrical contact is achieved by the presence of a barrier metal film. As the barrier metal film 16, titanium and/or titanium nitride can be cited.

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

Through the above steps, the processed body 100 is formed.

2.2. Chemical mechanical polishing method 2.2.1. The first grinding step Fig. 2 is a cross-sectional view schematically showing the object to be processed at the end of the first polishing step. In the first polishing step, as shown in FIG. 2, the tungsten film 18 is polished using the composition for chemical mechanical polishing until the barrier metal film 16 is exposed.

2.2.2. The second grinding step Fig. 3 is a cross-sectional view schematically showing the object to be processed at the end of the second polishing step. In the second polishing step, as shown in FIG. 3, the silicon oxide film 12, the barrier metal film 16, and the tungsten film 18 are polished using the composition for chemical mechanical polishing. By passing through the second polishing step, a next-generation semiconductor device 200 with excellent flatness of the polished surface can be manufactured.

Furthermore, as described above, the composition for chemical mechanical polishing is suitable as a polishing material for chemical mechanical polishing of a semiconductor substrate having a plurality of materials constituting a semiconductor device. Therefore, in the first polishing step and the second polishing step of the chemical mechanical polishing method of the present embodiment, the chemical mechanical polishing composition having the same composition can be used, and therefore the throughput of the production line is improved.

2.3. Chemical mechanical polishing device In the first polishing step and the second polishing step, for example, the polishing device 300 shown in FIG. 4 can be used. FIG. 4 is a perspective view schematically showing the polishing device 300. The first polishing step and the second polishing step are performed by supplying the slurry (composition for chemical mechanical polishing) 44 from the slurry supply nozzle 42 and turning the turntable on which the polishing cloth 46 is attached. While the turntable 48 rotates, the carrier head 52 holding the semiconductor substrate 50 is brought into contact with each other. Furthermore, in FIG. 4, the water supply nozzle 54 and the dresser 56 are also shown together.

The grinding load of the carrier head 52 can be selected in the range of 10 hPa to 980 hPa, preferably 30 hPa to 490 hPa. In addition, the rotation speed of the turntable 48 and the carrier head 52 can be appropriately selected in 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 in the range of 10 mL/minute to 1,000 mL/minute, and is preferably 50 mL/minute to 400 mL/minute.

Commercially available polishing devices include, for example, 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 Material; Models "POLI-400L" manufactured by G&P TECHNOLOGY; Models "POLI-400L" manufactured by AMAT "Reflexion LK" and so on.

3. Example Hereinafter, the present invention will be described through examples, but the present invention is not limited by these examples. In addition, the "parts" and "%" in this embodiment are quality standards unless otherwise specified.

3.1. Preparation of water dispersion of silica particles 3.1.1. Preparation of water dispersion A The mixture of 1522.2 g of tetramethoxysilane and 413.0 g of methanol was added dropwise to a mixture of 787.9 g of pure water, 786.0 g of 26% ammonia, and 12924 g of methanol while maintaining the liquid temperature at 35°C for 55 minutes to obtain hydrolysis. Of silica sol dispersion. The sol was heated and concentrated to 2900 ml under normal pressure. The concentrated liquid was further heated and distilled under normal pressure, and pure water was added dropwise while keeping the volume constant. When it was confirmed that the temperature at the top of the tower reached 100°C and the pH became less than 8, the dropwise addition of pure water was completed to obtain an aqueous dispersion A .

3.1.2. Preparation of Water Dispersion B A mixture of 19.0 g of methanol and 1.0 g of N-(3-trimethoxysilylpropyl)ethylenediamine was added dropwise to 540 g of aqueous dispersion A while keeping the liquid temperature at normal pressure. Reflux for 2 hours. Then, pure water was added dropwise while keeping the volume constant, the dropwise addition of pure water was terminated when the tower top temperature reached 100°C, and an aqueous dispersion B containing silica particles modified with a compound having two amine groups was obtained.

3.1.3. Preparation of Water Dispersion C In addition to using N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine instead of N-(3-trimethoxysilylpropyl)ethylenediamine, the same as [3.1 2. Preparation of Water Dispersion B] Similarly, water dispersion C containing silica particles modified with a compound having three amine groups was obtained.

3.1.4. Preparation of water dispersion D Except that 3-aminopropyltriethoxysilane was used instead of N-(3-trimethoxysilylpropyl)ethylenediamine, it was the same as [3.1.2. Preparation of Water Dispersion B] to obtain Aqueous dispersion D of silica particles modified with a compound having one amine group.

3.2. Preparation of chemical mechanical polishing composition Hydrogen peroxide (manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Hydrogen Peroxide (30% aqueous solution)") was used as the oxidizing agent, and the composition was shown in Table 1 to Table 3 in a polyethylene container Each component is added in the same manner, and potassium hydroxide is added as needed, and adjusted so that the pH shown in Tables 1 to 3 is adjusted, and adjusted with pure water so that the total amount of all the components becomes 100 parts by mass. In this way, the chemical mechanical polishing composition of each example and each comparative example was prepared.

For each chemical mechanical polishing composition obtained in this way, the average particle size of the abrasive grains will be measured using a particle size measuring device (Malvern (Malvern) company, model "Zetasizer nano (Zetasizer nano) zs"). Shown in Table 1 to Table 3 together.

For each chemical mechanical polishing composition obtained in this way, the results of measuring the zeta potential of the abrasive grains using a zeta potential measuring device (manufactured by Dispersion Technology Inc., model "DT300") are also shown in Table 1~ table 3.

3.3. Evaluation method 3.3.1. Grinding speed test Using the obtained chemical mechanical polishing composition, a 12-inch diameter wafer with a 300 nm CVD-W film or a 12-inch diameter wafer with a 300 nm p-TEOS film (silicon oxide film) As the object to be polished, the circle was subjected to a chemical mechanical polishing test for 60 seconds under the following polishing conditions.

＜Grinding conditions＞ • Grinding device: manufactured by AMAT, model "Reflexion LK" • Polishing pad: manufactured by Fujibo Holdings Co., Ltd., "Multi-hard polyurethane pad; H800-type1 (3-1S) 775" • Feed rate of chemical mechanical polishing composition: 300 mL/min •Pressure plate speed: 100 rpm • Head speed: 90 rpm • Head pressing pressure: 2.5 psi • Grinding speed (Å/min) = (thickness of the film before grinding-thickness of the film after grinding) / grinding time

Furthermore, the thickness of the tungsten film is measured by a resistivity measuring machine (made by KLA-Tencor, model "OmniMap RS100") and measured by the DC four-point probe method. The sheet resistance value and the volume resistivity of tungsten are calculated by the following formula. • Film thickness (Å)=[Volume resistivity of tungsten film (Ω·m)÷Surface resistance value (Ω)]×10 ¹⁰

The evaluation criteria of the polishing speed test are as follows. The results of the polishing rate of the tungsten film, the results of the polishing rate of the silicon oxide film, and the evaluation results are shown in Tables 1 to 3. (Evaluation criteria) • "A"... When the ratio of the tungsten polishing rate to the p-TEOS polishing rate is 0.1 or more and less than 1.0, the actual semiconductor polishing can easily ensure the balance of both polishing film speeds and is practical, so it is judged It is a good "A". • "B"... When the ratio of the tungsten polishing rate to the p-TEOS polishing rate is 1.0 or more, the actual semiconductor polishing cannot ensure the balance of the polishing film speeds on both sides, so it is difficult to be practical and judged as defective. "B ".

3.3.2. Flatness evaluation The following test substrate is used, that is, a 12-inch wafer with a 100 nm silicon oxide film formed is processed into a "SEMATECH 754" pattern with a depth of 100 nm, and a 10 nm TiN film is laminated and then laminated Test substrate made of 200 nm tungsten film (manufactured by SEMATECH INTERNATIONAL).

The above-mentioned test substrate was polished under the following conditions until the silicon oxide film was exposed. For the polished surface after polishing, use a stylus profile system (made by Bruker, model "Dektak XTL") to confirm the width of the tungsten wiring (line, L)/the width of the silicon oxide film wiring (Space, S) is the step difference (tungsten recess) of the tungsten/silicon oxide film wiring in the pattern part of 0.18 μm/0.18 μm, respectively. The evaluation criteria are as follows. The values of tungsten dents and the evaluation results are shown in Tables 1 to 3. (Evaluation criteria) • "A"... When the tungsten dent is less than 2 nm, it can be judged to be very good. • "B"... When the tungsten dent is 2 nm or more and less than 9 nm, it can be judged as good. • "C"... When the tungsten dent is 9 nm or more, it is judged to be defective.

3.4. Evaluation results The composition of the chemical mechanical polishing composition of each Example and each comparative example and each evaluation result are shown in the following Table 1-Table 3 below.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Composition for chemical mechanical polishing Abrasive particles type Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion B Compounds for surface modification Diamine Diamine Diamine Diamine Diamine Diamine Diamine Diamine Diamine Diamine Average particle size (nm) 66 66 66 66 66 66 66 66 66 66 Zeta potential (mV) 18 18 18 18 18 18 18 18 18 18 Content (mass%) 2.0 1.0 3.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 additive type Citric acid Citric acid Citric acid Maleic acid Malonate Nitric acid Citric acid Citric acid Citric acid Citric acid Content (mass%) 0.1 0.1 0.1 0.03 0.06 0.007 0.1 0.1 0.1 0.1 type Esleam AD-3172M Esleam AD-3172M Esleam AD-3172M Content (mass%) 0.01 0.05 0.1 Oxidant type hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide Content (mass%) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 pH 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Evaluation item Grinding speed Tungsten film polishing speed (Å/min) 354 230 370 340 325 290 300 278 265 297 Silicon oxide film polishing speed (Å/min) 413 270 445 412 416 345 383 403 415 397 Tungsten film polishing speed/Si oxide film polishing speed 0.86 0.85 0.83 0.83 0.78 0.84 0.78 0.69 0.64 0.75 Evaluation results A A A A A A A A A A Flatness evaluation Tungsten recess (nm) 5.0 5.2 3.6 3.4 3.6 4.2 2.8 1.8 1.2 2.8 Evaluation results B B B B B B B A A B

[Table 2] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 Composition for chemical mechanical polishing Abrasive particles type Water dispersion B Water dispersion B Water dispersion B Water dispersion B Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Compounds for surface modification Diamine Diamine Diamine Diamine Triamine Triamine Triamine Triamine Triamine Triamine Average particle size (nm) 66 66 66 66 67 67 67 67 67 67 Zeta potential (mV) 18 18 18 18 20 20 20 20 20 20 Content (mass%) 2.0 2.0 2.0 2.0 2.0 1.0 3.0 2.0 2.0 2.0 additive type Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Maleic acid Malonate Nitric acid Content (mass%) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.03 0.08 0.007 type NISSAN ANON LA Content (mass%) 0.005 Oxidant type hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide Content (mass%) 2.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 pH 3.0 2.1 4.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Evaluation item Grinding speed Tungsten film polishing speed (Å/min) 378 287 360 280 360 243 378 345 354 300 Silicon oxide film polishing speed (Å/min) 415 354 413 398 423 285 456 423 432 356 Tungsten film polishing speed/Si oxide film polishing speed 0.91 0.81 0.87 0.70 0.85 0.85 0.83 0.82 0.82 0.84 Evaluation results A A A A A A A A A A Flatness evaluation Tungsten recess (nm) 8.4 3.8 4.5 3.6 5.0 7.8 3.6 3.4 3.6 4.2 Evaluation results B B B B B B B B B B

[table 3] Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 Comparative example 1 Comparative example 2 Composition for chemical mechanical polishing Abrasive particles type Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion C Water dispersion A Water dispersion D Compounds for surface modification Triamine Triamine Triamine Triamine Triamine Triamine Triamine Triamine without Monoamine Average particle size (nm) 67 67 67 67 67 67 67 67 65 65 Zeta potential (mV) 20 20 20 20 20 20 20 20 3 10 Content (mass%) 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 additive type Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Citric acid Content (mass%) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.05 0.075 type Esleam AD-3172M Esleam AD-3172M Esleam AD-3172M NISSAN ANON LA Content (mass%) 0.01 0.05 0.1 0.005 Oxidant type hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide Content (mass%) 1.0 1.0 1.0 0.5 2.0 1.0 1.0 1.0 1.0 1.0 pH 3.0 3.0 3.0 3.0 3.0 2.1 4.0 3.0 3.0 3.0 Evaluation item Grinding speed Tungsten film polishing speed (Å/min) 311 290 270 298 402 289 402 310 286 331 Silicon oxide film polishing speed (Å/min) 396 418 430 411 419 367 432 412 271 327 Tungsten film polishing speed/Si oxide film polishing speed 0.79 0.69 0.63 0.73 0.96 0.79 0.93 0.75 1.06 1.01 Evaluation results A A A A A A A A B B Flatness evaluation Tungsten recess (nm) 2.8 1.8 1.2 2.8 8.3 3.8 8.2 3.6 9.2 9.4 Evaluation results B A A B B B B B C C

The following products or reagents were used for each component in Table 1 to Table 3 above. In addition, the content of the abrasive grains in the upper table 1-the upper table 3 shows the solid content concentration of each water dispersion. ＜Abrasive grains＞ • Water dispersion A～Water dispersion D: Water dispersion A～Water dispersion D of the prepared silica particles ＜Compounds for surface modification＞ • Monoamine: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "(3-Aminopropyltriethoxysilane)", 3-aminopropyltriethoxysilane • Diamine: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "3-(2-Aminoethylamino)propyltrimethoxysilane (3-(2-Aminoethylamino)propyltrimethoxysilane)", N-(3- Trimethoxysilyl propyl) ethylene diamine • Triamine: manufactured by Fujifilm Wako Pure Chemical Co., Ltd., trade name "trimethoxysilylpropyldiethylenetriamine", N-[2-[3-(trimethoxysilyl)propylamine Yl]ethyl]ethylenediamine ＜Acid compounds＞ • Citric acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Citric Acid" • Maleic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Maleic Acid" • Malonic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Malonic Acid (Malonic Acid)" • Nitric acid: manufactured by Kanto Chemical Co., Ltd., trade name "Nitric acid 1.38" ＜Water-soluble polymer＞ • esleam AD-3172M: manufactured by NOF Corporation, trade name "esleam AD-3172M" ＜Surface active agent＞ • NISSAN ANON LA: manufactured by NOF Corporation, trade name "NISSAN ANON" LA, sodium lauryl amino diacetate ＜Oxidant＞ • Hydrogen peroxide: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Hydrogen Peroxide (35% in Water)",

According to the evaluation results in Tables 1 to 3 above, when the chemical mechanical polishing composition of Example 1 to Example 28 is used, the tungsten film and p-TEOS film can be polished at a practical polishing rate, and it can be easily secured. The speed of both polishing films is balanced, and surface defects (tungsten dents) after polishing can be significantly reduced.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purposes and effects). In addition, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. In addition, the present invention includes a configuration that exerts the same function and effect as the configuration described in the embodiment or a configuration that can achieve the same purpose. In addition, the present invention includes a configuration obtained by adding a known technique to the configuration described in the embodiment.

10: Matrix 12: Silicon oxide film 14: Through hole 16: barrier metal film 18: Tungsten film 42: Slurry supply nozzle 44: Composition for chemical mechanical polishing (slurry) 46: Abrasive cloth 48: turntable 50: Semiconductor substrate 52: carrier head 54: Water supply nozzle 56: Dresser 100: processed body 200: Semiconductor device 300: Chemical mechanical polishing device

FIG. 1 is a cross-sectional view schematically showing a to-be-processed object used in the chemical mechanical polishing of this embodiment. Fig. 2 is a cross-sectional view schematically showing the object to be processed after the first polishing step. Fig. 3 is a cross-sectional view schematically showing the object to be processed after the second polishing step. Fig. 4 is a perspective view schematically showing a chemical mechanical polishing apparatus.

Claims (8)

A composition for chemical mechanical polishing, including: (A) Component: silica particles modified with a compound having two or more amine groups; and (B) Liquid medium. The chemical mechanical polishing composition according to claim 1, wherein the zeta potential of the component (A) in the chemical mechanical polishing composition is +10 mV or more. The chemical mechanical polishing composition according to claim 1 or 2, wherein the total mass of the chemical mechanical polishing composition is 100% by mass, The content of the component (A) is 0.1% by mass or more and 10% by mass or less. The chemical mechanical polishing composition according to any one of claims 1 to 3, which further contains an acid compound. The chemical mechanical polishing composition according to any one of claims 1 to 4, which further contains an oxidizing agent. The chemical mechanical polishing composition according to any one of claims 1 to 5, wherein the pH is 2 or more and 5 or less. A chemical mechanical polishing method includes the step of polishing a semiconductor substrate using the chemical mechanical polishing composition according to any one of claims 1 to 6. The chemical mechanical polishing method according to claim 7, 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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