WO2023026813A1

WO2023026813A1 - Chemical mechanical polishing composition, and polishing method

Info

Publication number: WO2023026813A1
Application number: PCT/JP2022/029923
Authority: WO
Inventors: 昂輝石牧; 壮一郎赤木; 祐吾田井; 清信窪田; 遼須原; 弥里山口
Original assignee: Jsr株式会社
Priority date: 2021-08-24
Filing date: 2022-08-04
Publication date: 2023-03-02
Also published as: TW202323463A

Abstract

Provided is a chemical mechanical polishing composition capable of chemically mechanically polishing a ruthenium- or molybdenum-containing semiconductor substrate while maintaining a stable polishing rate and suppressing the corrosion of ruthenium or molybdenum.　This chemical mechanical polishing composition contains an abrasive grain (A) and a compound (D) having at least one functional group selected from the group consisting of an amino group and salts thereof and at least one functional group selected from the group consisting of a carboxy group and salts thereof, wherein the abrasive grain (A) has at least one of functional groups represented by general formulae (1) to (4) below.　(1): -SO3 -M+ (2): -COO-M+ (3): -NR1R2 (4): -N+R1R2R3M-

Description

Chemical mechanical polishing composition and polishing method

The present invention relates to a chemical mechanical polishing composition and a polishing method using the same.

With the improvement of semiconductor integrated circuit manufacturing technology, there is a demand for high integration and high-speed operation of semiconductor elements. Along with this, the flatness of the semiconductor substrate surface required in the manufacturing process of fine circuits in semiconductor devices is becoming more stringent, and chemical mechanical polishing (CMP) is an indispensable technology in the manufacturing process of semiconductor devices. It has become.

In CMP, a chemical mechanical polishing composition is supplied onto a polishing pad attached to a surface plate, a semiconductor substrate is pressed against the polishing pad, and the semiconductor substrate and the polishing pad are slid against each other to polish the semiconductor substrate. It is a technology that chemically and mechanically polishes the In CMP, unevenness on the surface of a semiconductor substrate can be removed by chemical reaction with reagents and mechanical polishing with abrasive grains, and the surface can be planarized.

In recent years, methods of using a ruthenium film or a molybdenum film have been investigated in order to improve the embedding property of copper in concave portions when forming copper wiring of a semiconductor substrate manufactured through such CMP (for example, , see Patent Documents 1 to 3).

Japanese Patent Publication No. 2009-514219 Japanese Patent Publication No. 2010-535424 WO2019/151145

In such CMP, when the object to be polished contains ruthenium, a basic chemical mechanical polishing composition and Chemical mechanical polishing must be performed using a halogen-based oxidizing agent having high oxidizing power such as potassium periodate or potassium hypochlorite. However, when a basic chemical mechanical polishing composition is used, generation of ruthenium tetroxide gas can be suppressed, but insufficiently oxidized ruthenium oxide adheres to the surface of the polishing pad, degrading the polishing properties of the polishing pad. Let me. As a result, it becomes difficult to chemically mechanically polish a semiconductor substrate containing ruthenium while maintaining a stable polishing rate. On the other hand, if the object to be polished contains ruthenium or molybdenum, it is necessary to use an oxidizing agent with high oxidizing power. There is a risk.

Some aspects of the present invention provide a chemical mechanical polishing composition capable of chemically mechanically polishing a semiconductor substrate containing ruthenium or molybdenum while maintaining a stable polishing rate while suppressing corrosion of ruthenium or molybdenum. It provides

The present invention has been made to solve at least part of the above-mentioned problems, and can be implemented as any of the following aspects.

One aspect of the chemical mechanical polishing composition according to the present invention is
Abrasive grains (A);
containing a compound (D) having at least one functional group selected from the group consisting of an amino group and salts thereof and at least one functional group selected from the group consisting of a carboxy group and salts thereof; death,
The abrasive grain (A) has at least one functional group among the functional groups represented by the following general formulas (1) to (4).
- SO ₃ ^- M ⁺ (1)
- COO ^- M ⁺ (2)
(In formulas (1) and (2) above, M ⁺ represents a monovalent cation.)
-NR ¹ R ² (3)
-N ⁺ R ¹ R ² R ³ M ⁽ 4)
(In formulas (3) and (4) above, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. ^{M −} represents an anion.)

In one aspect of the chemical mechanical polishing composition,
The content of the compound (D) may be 0.005 to 5% by mass.

In any aspect of the chemical mechanical polishing composition,
The absolute value of the zeta potential of the abrasive grains (A) in the chemical mechanical polishing composition may be 10 mV or more.

In any aspect of the chemical mechanical polishing composition,
The pH may be 6 or more and 12 or less.

In any aspect of the chemical mechanical polishing composition,
The pH may be 1.5 or more and 4 or less.

In any aspect of the chemical mechanical polishing composition,
The abrasive grains (A) in the chemical mechanical polishing composition may have an average secondary particle size of 5 nm or more and 70 nm or less.

One aspect of the polishing method according to the present invention is
A step of polishing a semiconductor substrate using the chemical mechanical polishing composition according to any one of the above aspects.

In one aspect of the polishing method,
The semiconductor substrate may have a portion composed of at least one selected from the group consisting of ruthenium, molybdenum, ruthenium alloys and molybdenum alloys.

According to the chemical mechanical polishing composition of the present invention, it is possible to perform chemical mechanical polishing on a semiconductor substrate containing ruthenium or molybdenum while maintaining a stable polishing rate while suppressing corrosion of ruthenium or molybdenum.

FIG. 1 is a cross-sectional view schematically showing an object to be processed suitable for use in the polishing process according to this embodiment. FIG. 2 is a cross-sectional view schematically showing the object to be processed at the end of the first polishing step. FIG. 3 is a cross-sectional view schematically showing the object to be processed at the end of the second polishing step. FIG. 4 is a perspective view schematically showing a chemical mechanical polishing apparatus.

A preferred embodiment of the present invention will be described in detail below. In addition, the present invention is not limited to the following embodiments, and includes various modifications implemented without changing the gist of the present invention.

In this specification, the numerical range described as "A to B" is interpreted as including the numerical value A as the lower limit and the numerical value B as the upper limit.

1. Chemical Mechanical Polishing Composition A chemical mechanical polishing composition according to one embodiment of the present invention comprises abrasive grains (A) (also referred to herein as “component (A)”), amino groups and salts thereof. A compound (D) having at least one functional group selected from the group consisting of a carboxy group and at least one functional group selected from the group consisting of salts thereof (herein referred to as "component (D )”), and the abrasive grain (A) has at least one functional group among the functional groups represented by the following general formulas (1) to (4).
- SO ₃ ^- M ⁺ (1)
- COO ^- M ⁺ (2)
(In formulas (1) and (2) above, M ⁺ represents a monovalent cation.)
-NR ¹ R ² (3)
-N ⁺ R ¹ R ² R ³ M ⁽ 4)
(In formulas (3) and (4) above, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. ^{M −} represents an anion.)
Hereinafter, each component contained in the chemical mechanical polishing composition according to this embodiment will be described in detail.

1.1. Component (A)
The chemical mechanical polishing composition according to this embodiment contains abrasive grains (A). Component (A) includes inorganic particles such as silica, ceria, alumina, zirconia, and titania, with silica particles being preferred. Examples of silica particles include fumed silica, colloidal silica, etc. Among them, colloidal silica is preferred. Colloidal silica is preferably used from the viewpoint of reducing polishing defects such as scratches. As colloidal silica, for example, one produced by the method described in JP-A-2003-109921 can be used.

When the component (A) is silica particles containing silica as the main component, it may further contain other components. Other components include aluminum compounds, silicon compounds, and the like. By further containing an aluminum compound or a silicon compound in the silica particles, the surface hardness of the silica particles can be reduced, so the occurrence of polishing scratches and dishing on the surface to be polished can be further reduced while maintaining a stable polishing rate. Sometimes we can.

Examples of aluminum compounds include aluminum hydroxide, aluminum oxide (alumina), aluminum chloride, aluminum nitride, aluminum acetate, aluminum phosphate, aluminum sulfate, sodium aluminate, and potassium aluminate. On the other hand, silicon compounds include silicon nitride, silicon carbide, silicates, silicones, silicon resins, and the like.

The shape of component (A) is not particularly limited, and may be spherical, cocoon-shaped, chain-spherical, or have a plurality of projections on the surface. Abrasive grains having a plurality of projections on their surfaces can be produced by applying the methods described in, for example, Japanese Patent Application Laid-Open No. 2007-153732 and Japanese Patent Application Laid-Open No. 2013-121631.

The absolute value of the zeta potential of component (A) in the chemical mechanical polishing composition is preferably 10 mV or more, more preferably 15 mV or more, and particularly preferably 20 mV or more. When the absolute value of the zeta potential of the component (A) is within the above range, the electrostatic repulsive force between the abrasive grains effectively prevents the particles from aggregating, and the semiconductor substrate containing ruthenium or molybdenum can be polished at a more stable polishing rate. can be polished with As the zeta potential measuring device, "ELSZ-2000ZS" manufactured by Otsuka Electronics Co., Ltd., "Zetasizer Ultra" manufactured by Malvern, Dispersion Technology Inc. and "DT300" manufactured by K.K.

When the object to be polished contains ruthenium, the average secondary particle size of component (A) in the chemical mechanical polishing composition is preferably 20 nm or more, more preferably 50 nm or more. When the object to be polished contains ruthenium, the average secondary particle size of component (A) in the chemical mechanical polishing composition is preferably 70 nm or less, more preferably 60 nm or less. When the average secondary particle size of the component (A) is within the above range, the chemical mechanical polishing composition can provide a sufficient polishing rate for a ruthenium film and has excellent stability without sedimentation and separation of particles. is obtained. The average secondary particle size of the component (A) in the chemical mechanical polishing composition can be measured using a particle size distribution analyzer that employs a dynamic light scattering method. Examples of such a particle size distribution analyzer include model "Zetasizer Ultra" manufactured by Malvern. The average secondary particle size was calculated by volume conversion.

When the object to be polished contains molybdenum, the average secondary particle size of component (A) in the chemical mechanical polishing composition is preferably 5 nm or more, more preferably 7 nm or more. When the object to be polished contains molybdenum, the average secondary particle size of component (A) in the chemical mechanical polishing composition is preferably 70 nm or less, more preferably 60 nm or less. When the average secondary particle size of component (A) is within the above range, mechanical polishing performance is reduced due to the small particle size, but surface free energy is increased to improve reactivity with molybdenum. It is possible to obtain a chemical mechanical polishing composition which provides a sufficient polishing rate for a molybdenum film and has excellent stability without sedimentation and separation of particles.

At least part of the surface of component (A) has at least one functional group represented by the following general formulas (1) to (4) (hereinafter also referred to as "specific functional group"): .
- SO ₃ ^- M ⁺ (1)
- COO ^- M ⁺ (2)
(In formulas (1) and (2) above, M ⁺ represents a monovalent cation.)
-NR ¹ R ² (3)
-N ⁺ R ¹ R ² R ³ M ⁽ 4)
(In formulas (3) and (4) above, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. ^{M −} represents an anion.)

Abrasive grains having at least a portion of the surface modified with specific functional groups have a larger absolute value of zeta potential than abrasive grains not surface-modified with specific functional groups, so the electrostatic repulsion between abrasive grains is reduced. increase. As a result, the dispersibility of the abrasive grains in the chemical mechanical polishing composition is improved, so that high-speed polishing can be performed while reducing the occurrence of polishing scratches and dishing.

Component (A) can have a functional group represented by the following general formula (1).
- SO ₃ ^- M ⁺ (1)
(M ⁺ represents a monovalent cation.)

Examples of monovalent cations represented by M ⁺ in general formula (1) include, but are not limited to, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ . That is, the functional group represented by the general formula (1) can be rephrased as "at least one functional group selected from the group consisting of a sulfo group and a salt thereof". Here, the "salt of a sulfo group" means that the hydrogen ion contained in the sulfo group (--SO ₃ H) is replaced with a monovalent cation such as Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ Refers to functional groups. Component (A) having a functional group represented by the general formula (1) is an abrasive grain having a functional group represented by the general formula (1) fixed to its surface via a covalent bond. Abrasive grains to which a compound having a functional group represented by the general formula (1) is physically or ionically adsorbed on the surface are not included.

The component (A) having the functional group represented by the above general formula (1) can be produced as follows. First, silica prepared by a known method and a mercapto group-containing silane coupling agent are sufficiently stirred in an acidic medium to covalently bond the mercapto group-containing silane coupling agent to the surface of the silica. Examples of mercapto group-containing silane coupling agents include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Next, by further adding an appropriate amount of hydrogen peroxide and allowing to stand sufficiently, the component (A) having the functional group represented by the general formula (1) can be obtained.

The zeta potential of the component (A) having a functional group represented by the general formula (1) is a negative potential in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less. It is preferably -15 mV or less, and particularly preferably -20 mV or less. When the zeta potential of the component (A) is within the above range, the electrostatic repulsive force between the abrasive grains effectively prevents particles from aggregating with each other, and a semiconductor substrate containing ruthenium or molybdenum can be polished at a more stable polishing rate. Sometimes. In addition, the apparatus mentioned above can be used for a zeta-potential measuring apparatus. The zeta potential of component (A) can be adjusted by appropriately increasing or decreasing the amount of the mercapto group-containing silane coupling agent or the like added.

When the chemical mechanical polishing composition according to the present embodiment contains component (A) having a functional group represented by general formula (1) above, the content of component (A) is is preferably 0.5% by mass or more, and more preferably 1% by mass or more, when the total mass of is 100% by mass. The content of component (A) is preferably 10% by mass or less, more preferably 5% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass. When the content of the component (A) having a functional group represented by the general formula (1) is within the above range, a semiconductor substrate containing ruthenium or molybdenum can be polished at a stable polishing rate, and the composition for chemical mechanical polishing The storage stability of the product may be improved.

Component (A) can have a functional group represented by the following general formula (2).
- COO ^- M ⁺ (2)
(M ⁺ represents a monovalent cation.)

Examples of monovalent cations represented by M ⁺ in general formula (2) include, but are not limited to, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ . That is, the functional group represented by the above general formula (2) can also be rephrased as "at least one functional group selected from the group consisting of a carboxy group and a salt thereof". Here, the term "salt of carboxyl group" refers to a functional group obtained by substituting a monovalent cation such as Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ for the hydrogen ion contained in the carboxyl group (-COOH). That's what I mean. The component (A) having the functional group represented by the general formula (2) is an abrasive grain having the functional group represented by the general formula (2) fixed to its surface via a covalent bond. Abrasive grains to which a compound having a functional group represented by the general formula (2) is physically or ionically adsorbed on the surface are not included.

The component (A) having the functional group represented by the general formula (2) can be produced as follows. First, silica prepared by a known method and a carboxylic anhydride-containing silane coupling agent are sufficiently stirred in a basic medium to covalently bond the carboxylic anhydride-containing silane coupling agent to the surface of the abrasive grains. Abrasive grains having a functional group represented by the above general formula (2) can be obtained by allowing the Examples of the carboxylic anhydride-containing silane coupling agent include 3-(triethoxysilyl)propylsuccinic anhydride.

The zeta potential of the component (A) having a functional group represented by the general formula (2) is a negative potential in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less. It is preferably -15 mV or less, and particularly preferably -20 mV or less. When the zeta potential of the component (A) is within the above range, the electrostatic repulsive force between the abrasive grains effectively prevents particles from aggregating with each other, and a semiconductor substrate containing ruthenium or molybdenum can be polished at a more stable polishing rate. Sometimes. In addition, the apparatus mentioned above can be used for a zeta-potential measuring apparatus. The zeta potential of the component (A) having the functional group represented by the general formula (2) can be adjusted by appropriately increasing or decreasing the amount of the above-described carboxylic anhydride-containing silane coupling agent or the like added.

When the chemical mechanical polishing composition according to the present embodiment contains the component (A) represented by the general formula (2), the content of the component (A) is the total mass of the chemical mechanical polishing composition. Based on 100% by mass, the content is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. The content of component (A) is preferably 10% by mass or less, more preferably 8% by mass or less, particularly preferably 5% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. % by mass or less. When the content of component (A) is within the above range, a semiconductor substrate containing ruthenium or molybdenum can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may be improved.

Component (A) can have a functional group represented by the following general formula (3) and/or the following general formula (4).
-NR ¹ R ² (3)
-N ⁺ R ¹ R ² R ³ M ⁽ 4)
(In formulas (3) and (4) above, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. ^{M −} represents an anion. .)

The functional group represented by the above general formula (3) represents an amino group, and the functional group represented by the above general formula (4) represents a salt of the amino group. Therefore, the functional group represented by the general formula (3) and the functional group represented by the general formula (4) are collectively referred to as "at least one functional group selected from the group consisting of an amino group and a salt thereof. ” can also be rephrased. The component (A) having a functional group represented by the general formula (3) and/or the general formula (4) is represented by the general formula (3) and/or the general formula (4) on its surface. The functional group is an abrasive grain fixed via a covalent bond, and the compound having the functional group represented by the general formula (3) and / or the general formula (4) on the surface is physically or ionic Abrasive grains such as those adsorbed to are not included.

In the above general formula (4), the anions represented by M ⁻ are not limited to these, but anions such as OH ⁻ , F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ and the like , and anions derived from acidic compounds.

In general formulas (3) and (4) above, each of R ¹ to R ³ independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, and two of R ¹ to R ³ Two or more may combine to form a ring structure.

The hydrocarbon group represented by R ¹ to R ³ may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, or an alicyclic hydrocarbon group. Moreover, the aliphatic of the aliphatic hydrocarbon group and the araliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. These hydrocarbon groups include, for example, linear, branched or cyclic alkyl groups, alkenyl groups, aralkyl groups, and aryl groups.

The alkyl group is preferably a lower alkyl group having 1 to 6 carbon atoms, more preferably a lower alkyl group having 1 to 4 carbon atoms. Examples of such alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group and n-pentyl group. , iso-pentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, cyclopentyl group, cyclohexyl group and the like.

The alkenyl group is preferably a lower alkenyl group having 1 to 6 carbon atoms, more preferably a lower alkenyl group having 1 to 4 carbon atoms. Examples of such alkenyl groups include vinyl groups, n-propenyl groups, iso-propenyl groups, n-butenyl groups, iso-butenyl groups, sec-butenyl groups, tert-butenyl groups and the like.

The aralkyl group preferably has 7 to 12 carbon atoms. Examples of such aralkyl groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylhexyl, methylbenzyl, methylphenethyl and ethylbenzyl groups.

The aryl group preferably has 6 to 14 carbon atoms. Examples of such aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2 ,6-xylyl group, 3,5-xylyl group, naphthyl group, anthryl group and the like.

The aromatic rings of the above aryl groups and aralkyl groups may have, for example, lower alkyl groups such as methyl groups and ethyl groups, halogen atoms, nitro groups, amino groups, hydroxy groups, etc. as substituents.

The component (A) having a functional group represented by the general formula (3) and / or the general formula (4) is obtained by, for example, sufficiently stirring silica and an amino group-containing silane coupling agent in an acidic medium, By covalently bonding an amino group-containing silane coupling agent to the surface of silica, abrasive grains having functional groups represented by the general formula (3) and/or the general formula (4) can be produced. Examples of amino group-containing silane coupling agents include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

When the pH of the chemical mechanical polishing composition is 6 or more and 12 or less, the zeta potential of component (A) having a functional group represented by general formula (3) and/or general formula (4) is It has a negative potential in the polishing composition, and the negative potential is preferably -10 mV or less, more preferably -15 mV or less. When the pH of the chemical mechanical polishing composition is 1.5 or more and 4 or less, the component (A) having the functional group represented by the general formula (3) and/or the general formula (4) has a positive zeta potential. potential, and its positive potential is preferably 10 mV or more, more preferably 15 mV or more. When the zeta potential of the component (A) is within the above range, the electrostatic repulsive force between the abrasive grains effectively prevents particles from aggregating with each other, and a semiconductor substrate containing ruthenium or molybdenum can be polished at a more stable polishing rate. Sometimes. In addition, the apparatus mentioned above can be used for a zeta-potential measuring apparatus. The zeta potential of the component (A) having a functional group represented by the general formula (3) and/or the general formula (4) can be adjusted by appropriately increasing or decreasing the amount of the amino group-containing silane coupling agent or the like added. can be adjusted by

When the chemical mechanical polishing composition according to the present embodiment contains a component (A) having a functional group represented by the general formula (3) and/or the general formula (4), the component (A) is contained The amount is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass when the total mass of the chemical mechanical polishing composition is 100% by mass. That's it. The content of component (A) is preferably 10% by mass or less, more preferably 8% by mass or less, particularly preferably 5% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. % by mass or less. When the content of component (A) is within the above range, a semiconductor substrate containing ruthenium or molybdenum can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may be improved.

1.2. Component (D)
The chemical mechanical polishing composition according to the present embodiment contains at least one functional group selected from the group consisting of amino groups and salts thereof, and at least one functional group selected from the group consisting of carboxy groups and salts thereof. It contains a compound (D) having a group and Component (D) can suppress excessive corrosion of ruthenium and molybdenum sites by adsorbing to the surface of a semiconductor substrate containing ruthenium or molybdenum to form a protective film.

Amino groups and salts thereof include functional groups represented by the following general formula (5) or (6).
-NR ⁴ R ⁵ (5)
- N ⁺ R ⁴ R ⁵ R ⁶ M ^- (6)
(In formulas (5) and (6) above, R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. ^{M −} represents an anion. show.)

In general formulas (5) and (6) above, each of R ⁴ to R ⁶ independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, and two of R ⁴ to R ⁶ Two or more may combine to form a ring structure.

The hydrocarbon groups represented by R ⁴ to R ⁶ may be aliphatic hydrocarbon groups, aromatic hydrocarbon groups, araliphatic hydrocarbon groups or alicyclic hydrocarbon groups. Moreover, the aliphatic of the aliphatic hydrocarbon group and the araliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. These hydrocarbon groups include, for example, linear, branched or cyclic alkyl groups, alkenyl groups, aralkyl groups, and aryl groups.

The aromatic ring of the aryl group and the aralkyl group may have, for example, a lower alkyl group such as a methyl group or an ethyl group, a halogen atom, a nitro group, an amino group, a hydroxy group, or the like, as a substituent.

The carboxy group and its salt include functional groups represented by the following general formula (7).
- COO ^- M ⁺ (7)
(M ⁺ represents a monovalent cation.)

Examples of monovalent cations represented by M ⁺ in general formula (7) include, but are not limited to, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

Component (D) is a structure having at least one functional group selected from the group consisting of amino groups and salts thereof and at least one functional group selected from the group consisting of carboxy groups and salts thereof. Although not particularly limited, it preferably has a structure represented by the following general formula (8).
—N(CH ₂ COO ^— M ⁺ ) _n ( ^R ) _2-n (8)
(In formula (8) above, R ⁷ represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. M ⁺ represents a monovalent cation. n represents an integer of 1 to 2.)

In general formula (8) above, examples of the hydrocarbon group represented by R ⁷ include the same hydrocarbon groups as the hydrocarbon groups exemplified for R ⁴ to R ⁶ in general formulas (6) and (7) above. be done. Examples of the monovalent cation represented by M ⁺ in the general formula (8) include, but are not limited to, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

Since component (D) has a structure represented by the above general formula (8), component (D) is effectively coordinated to the surface of ruthenium or molybdenum and adsorbed to form a protective film. Excessive corrosion of ruthenium sites and molybdenum sites can be suppressed.

Component (D) includes, for example, N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, N-(2-carboxyethyl)iminodiacetic acid, ethylenediaminetetraacetic acid, L-glutamic acid diacetic acid tetraacetic acid Sodium, glycine-N,N-bis(methylenephosphonic acid), 3,3′,3″-nitrilotripropionic acid, glycol ether diamine tetraacetic acid, hydroxyethylethylenediamine triacetic acid, 1,3-propanediamine-N,N ,N′,N′-tetraacetic acid, triethylenetetraaminehexaacetic acid, dihydroxyethylglycine, (S,S)-ethylenediaminedisuccinic acid trihydrate, iminodiacetic acid, trans-1,2-diaminocyclohexane-N , N,N',N'-tetraacetic acid hydrate and the like. These component (D) may be used individually by 1 type, and may be used in combination of 2 or more type.

The content (% by mass) of component (D) is preferably 0.05% by mass or more, more preferably 0.1% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. or more, and particularly preferably 0.15% by mass or more. The content (% by mass) of component (D) is preferably 5% by mass or less, more preferably 2% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass, Particularly preferably, it is 1% by mass or less. When the content of component (D) is within the above range, excessive corrosion of semiconductor substrates containing ruthenium or molybdenum can be effectively suppressed in some cases.

1.3. Component (B)
The chemical mechanical polishing composition according to the present embodiment contains periodate ions (IO ₄ ⁻ ), hypochlorite ions (ClO ⁻ ), chlorite ions (ClO ₂ ⁻ ) and hypobromite ions (BrO ^- ) containing an acid or a salt thereof (B) containing at least one anion selected from the group consisting of (hereinafter also referred to as "specific anion species"). It is presumed that the anion contained in component (B) functions as an oxidizing agent and oxidizes ruthenium and molybdenum to promote polishing.

Specific examples of component (B) include periodic acid, chlorous acid, hypochlorous acid, hypobromous acid, sodium periodate, potassium periodate, ammonium periodate, sodium chlorite, and chlorine. potassium hypochlorite, sodium hypochlorite, potassium hypochlorite, sodium hypobromite and the like. Among these, at least one compound selected from the group consisting of periodic acid, potassium chlorite, potassium hypochlorite and sodium hypobromite is preferred, and periodic acid is more preferred. Component (B) may be used alone or in combination of two or more.

The content (mol/L) of component (B) is preferably 0.001 mol/L or more, more preferably 0.002 mol/L or more, and particularly preferably 1 L of the chemical mechanical polishing composition. is 0.003 mol/L or more. The content (mol/L) of component (B) is preferably 0.05 mol/L or less, more preferably 0.04 mol/L or less, and particularly preferably 1 L of the chemical mechanical polishing composition. is 0.035 mol/L or less. When the content of component (B) is within the above range, ruthenium or molybdenum is oxidized to promote polishing, and excessive reaction between ruthenium or molybdenum and specific anion species can be prevented, thereby suppressing corrosion of ruthenium or molybdenum. Sometimes.

The content (% by mass) of component (B) is preferably 0.01% by mass or more, more preferably 0.05% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. or more, and particularly preferably 0.1% by mass or more. The content (% by mass) of component (B) is preferably 10% by mass or less, more preferably 8% by mass or less when the total mass of the chemical mechanical polishing composition is 100% by mass, Especially preferably, it is 7% by mass or less. When the content of component (B) is within the above range, ruthenium or molybdenum is oxidized to promote polishing, and excessive reaction between ruthenium or molybdenum and specific anion species can be prevented, thereby suppressing corrosion of ruthenium or molybdenum. Sometimes.

1.4. Component (C)
The chemical mechanical polishing composition according to the present embodiment may contain hydrogen peroxide (C) (also referred to herein as "component (C)"). Hydrogen peroxide (C) oxidizes ruthenium and molybdenum to promote polishing, and component (C) reacts with ruthenium and molybdenum to form a bond between ruthenium and molybdenum and the specific anion species contained in component (B). It has the function of preventing excessive reactions and suppressing the generation of halogen gas and the corrosion of ruthenium and molybdenum.

The content (mol/L) of component (C) is preferably 0.0005 mol/L or more, more preferably 0.0009 mol/L or more, and particularly preferably 1 L of the chemical mechanical polishing composition. is 0.0012 mol/L or more. The content (mol/L) of component (C) is preferably 0.5 mol/L or less, more preferably 0.4 mol/L or less, and particularly preferably 1 L of the chemical mechanical polishing composition. is 0.3 mol/L or less. When the content of component (C) is within the above range, ruthenium and molybdenum are oxidized to promote polishing, and component (C) reacts with ruthenium and molybdenum to form ruthenium and molybdenum contained in component (B). Excessive reaction with a specific anion species that is contained in the metal can be prevented, and corrosion of ruthenium and molybdenum can be suppressed.

The content (% by mass) of component (C) is preferably 0.0017% by mass or more, more preferably 0.003% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. or more, particularly preferably 0.004% by mass or more. The content (% by mass) of component (C) is preferably 1.7% by mass or less, more preferably 1.4% by mass, when the total mass of the chemical mechanical polishing composition is 100% by mass. or less, and particularly preferably 1% by mass or less. When the content of component (C) is within the above range, ruthenium and molybdenum are oxidized to promote polishing, and component (C) reacts with ruthenium and molybdenum to form ruthenium and molybdenum contained in component (B). Excessive reaction with a specific anion species that is contained in the metal can be prevented, and corrosion of ruthenium and molybdenum can be suppressed.

1.5. Other Components The chemical mechanical polishing composition according to the present embodiment contains, in addition to the components described above, a liquid medium, an onium salt, an iron (III) compound, a water-soluble polymer, and a nitrogen-containing heterocyclic compound, if necessary. , surfactants, organic acids and salts thereof, inorganic acids and salts thereof, basic compounds and the like.

<Liquid medium>
The chemical mechanical polishing composition according to this embodiment contains a liquid medium. The liquid medium includes water, a mixed medium of water and alcohol, a mixed medium containing water and an organic solvent compatible with water, and the like. Among these, it is preferable to use water or a mixed medium of water and alcohol, and it is more preferable to use water. Pure water can be preferably used as a raw material of water. The liquid medium may be blended as the balance of each component described above.

<Onium salt>
The chemical mechanical polishing composition according to this embodiment may contain an onium salt. It is believed that the onium salt is adsorbed on the surface of the molybdenum film to form a protective film, thereby reducing corrosion of the molybdenum film. The onium salt is not particularly limited as long as it is a compound containing an onium ion, but an onium salt represented by the following general formula (9) is preferable.

(In Formula (9), R ⁸ , R ⁹ and R ¹⁰ each independently represent an alkyl group having n or less carbon atoms, R ¹¹ represents an alkyl group, an aryl group or a hydroxy group. M ⁻ is represents a monovalent anion. n represents an integer of 1 or more.)

Specific examples of the onium salt represented by the general formula (9) include ethyltrimethylammonium hydroxide, propyltrimethylammonium hydroxide, octyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, 1-hydroxyethyltrimethylammonium hydroxide 2-hydroxyethyltrimethylammonium hydroxide, 1-hydroxypropyltrimethylammonium hydroxide, 2-hydroxypropyltrimethylammonium hydroxide, benzyltrimethylammonium hydroxide and the like. Among these, ethyltrimethylammonium hydroxide and 2-hydroxyethyltrimethylammonium hydroxide are preferred. These onium salts may be used singly or in combination of two or more.

When the chemical mechanical polishing composition according to the present embodiment contains an onium salt, the content of the onium salt is preferably 0.005 mass % when the total mass of the chemical mechanical polishing composition is 100 mass %. % or more, more preferably 0.01 mass % or more. The content of the onium salt is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass.

<Iron (III) compound>
The chemical mechanical polishing composition according to this embodiment may contain an iron (III) compound. Iron (III) compounds can oxidize molybdenum to create a brittle modified layer on the surface of the molybdenum film, which can facilitate polishing of the molybdenum film.

The iron (III) compound may be either an organic acid iron salt or an inorganic acid iron salt as long as it has the effects described above. Examples of iron (III) compounds include iron (III) nitrate, iron (III) ammonium sulfate, iron (III) perchlorate, iron (III) chloride, iron (III) sulfate, iron (III) citrate, citric iron (III) ammonium oxalate, iron (III) ammonium oxalate, iron (III) acetylacetonate, and the like. Of these iron(III) compounds, iron(III) nitrate, iron(III) citrate and iron(III) acetylacetonate are preferred, with iron(III) nitrate being particularly preferred. By using these iron (III) compounds, an oxide can be formed on the molybdenum surface, making it easy to scrape off the oxide with the component (A), suppressing residue, dishing and corrosion, A flat polished surface can be obtained while maintaining a good polishing rate. These iron (III) compounds may be used singly or in combination of two or more.

When the chemical mechanical polishing composition according to the present embodiment contains an iron (III) compound, the content of the iron (III) compound is It is preferably 0.001% by mass or more, more preferably 0.01% by mass or more. The content (% by mass) of the iron (III) compound is preferably 1% by mass or less, more preferably 0.1% by mass or less when the total mass of the chemical mechanical polishing composition is 100% by mass. is. When the content of the iron (III) compound is within the above range, the surface of molybdenum can be effectively oxidized, so it is thought that the molybdenum polishing rate can be further increased and dishing and erosion can be effectively suppressed. be done.

<Water-soluble polymer>
The chemical mechanical polishing composition according to this embodiment may contain a water-soluble polymer. The water-soluble polymer may adsorb to the surface of the surface to be polished, reduce polishing friction, and reduce the occurrence of dishing on the surface to be polished.

Specific examples of water-soluble polymers include polycarboxylic acid, polystyrenesulfonic acid, polyacrylic acid, polymethacrylic acid, polyether, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyallylamine, and hydroxyethylcellulose. . These can be used singly or in combination of two or more.

The weight average molecular weight (Mw) of the water-soluble polymer is preferably 10,000 or more and 1,500,000 or less, more preferably 40,000 or more and 1,200,000 or less. Here, "weight average molecular weight" refers to weight average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography).

When the chemical mechanical polishing composition according to the present embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably It is 0.001% by mass or more, more preferably 0.002% by mass or more. The content of the water-soluble polymer is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass.

<Nitrogen-containing heterocyclic compound>
A nitrogen-containing heterocyclic compound is an organic compound containing at least one heterocyclic ring selected from five- and six-membered heterocyclic rings having at least one nitrogen atom. Specific examples of the heterocyclic ring include five-membered heterocyclic rings such as pyrrole structure, imidazole structure and triazole structure; six-membered heterocyclic rings such as pyridine structure, pyrimidine structure, pyridazine structure and pyrazine structure. The heterocycle may form a condensed ring. Specific examples include an indole structure, an isoindole structure, a benzimidazole structure, a benzotriazole structure, a quinoline structure, an isoquinoline structure, a quinazoline structure, a cinnoline structure, a phthalazine structure, a quinoxaline structure, and an acridine structure. Among heterocyclic compounds having such structures, heterocyclic compounds having a pyridine structure, a quinoline structure, a benzimidazole structure, and a benzotriazole structure are preferred.

Specific examples of nitrogen-containing heterocyclic compounds include aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indole, quinoline, isoquinoline, benzoisoquinoline, purine, pteridine, triazole, triazolidine, benzotriazole, carboxy Benzotriazoles and derivatives having these skeletons are included. Among these, at least one selected from the group consisting of benzotriazole and triazole is preferred. These nitrogen-containing heterocyclic compounds may be used singly or in combination of two or more.

<Surfactant>
The surfactant is not particularly limited, and anionic surfactants, cationic surfactants, nonionic surfactants and the like can be used. Examples of anionic surfactants include sulfates such as 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. Nonionic surfactants include, for example, nonionic surfactants having a triple bond such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohol; polyethylene glycol type surfactants and the like. These surfactants may be used singly or in combination of two or more.

<Organic acid and its salt>
The chemical mechanical polishing composition according to this embodiment may contain at least one selected from the group consisting of organic acids and salts thereof (excluding component (D)). The organic acid and its salt may be able to improve the polishing rate of a semiconductor substrate containing ruthenium or molybdenum due to a synergistic effect with component (A).

The organic acid and its salt are preferably compounds having a carboxy group and compounds having a sulfo group. Examples of compounds having a carboxy group include stearic acid, lauric acid, oleic acid, myristic acid, alkenylsuccinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, formic acid, acetic acid, oxalic acid, citric acid, acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinolinic acid, quinaldic acid, amidosulfuric acid, propionic acid, trifluoroacetic acid; glycine, alanine, aspartic acid, glutamic acid, lysine, arginine, tryptophan, dodecylamino amino acids such as ethylaminoethylglycine, aromatic amino acids and heterocyclic amino acids; imino acids such as alkyliminodicarboxylic acids; and salts thereof. Examples of compounds having a sulfo group include alkylbenzenesulfonic acids such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid; alkylnaphthalenesulfonic acids such as butylnaphthalenesulfonic acid; α-olefinsulfonic acids such as tetradecenesulfonic acid; These salts are mentioned. These compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

When the chemical mechanical polishing composition according to the present embodiment contains an organic acid (salt), the content of the organic acid (salt) is It is preferably 0.001% by mass or more, more preferably 0.01% by mass or more. The content of the organic acid (salt) is preferably 5% by mass or less, more preferably 1% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass.

<Inorganic acid and its salt>
The inorganic acid is preferably at least one selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and salts thereof. The inorganic acid may form a salt with a separately added base in the chemical mechanical polishing composition.

<Basic compound>
Basic compounds include organic bases and inorganic bases. Preferred organic bases are amines such as triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine, diglycolamine and isopropylamine. be done. Examples of inorganic bases include ammonia, potassium hydroxide, sodium hydroxide and the like. Among these basic compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

1.6. pH
When the object to be polished contains ruthenium, the pH of the chemical mechanical polishing composition according to this embodiment is preferably 6.0 or higher, more preferably 6.5 or higher, and particularly preferably 7.0 or higher. be. When the object to be polished contains ruthenium, the pH of the chemical mechanical polishing composition according to this embodiment is preferably 12.0 or less, more preferably 11.0 or less, and particularly preferably 10.0 or less. be. When the pH is within the above range, the generation of ruthenium tetroxide gas and the corrosion of ruthenium can be effectively suppressed in some cases.

When the object to be polished contains molybdenum, the pH of the chemical mechanical polishing composition according to the present embodiment is preferably 1.5 or higher, more preferably 2.0 or higher. When the object to be polished contains molybdenum, the pH of the chemical mechanical polishing composition according to this embodiment is preferably 4.0 or less, more preferably 3.5 or less. When the pH is within the above range, corrosion of molybdenum can be effectively suppressed in some cases.

The pH of the chemical mechanical polishing composition can be adjusted, for example, by adding the aforementioned organic acid (salt), inorganic acid (salt), basic compound, or the like, and one or more of these can be used. be able to.

In the present invention, pH refers to hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, desktop pH meter manufactured by Horiba Ltd.).

1.7. Method for Preparing Chemical Mechanical Polishing Composition The chemical mechanical polishing composition according to the present embodiment can be prepared by dissolving or dispersing each component described above in a liquid medium such as water. The method of dissolving or dispersing is not particularly limited, and any method may be applied as long as it can dissolve or disperse uniformly. Also, the mixing order and mixing method of the components described above are not particularly limited.

The chemical mechanical polishing composition can also be prepared as a concentrated type stock solution and diluted with a liquid medium such as water at the time of use.

2. 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 described above. The chemical mechanical polishing composition can chemically mechanically polish a semiconductor substrate containing ruthenium or molybdenum while maintaining a stable polishing rate while suppressing corrosion of ruthenium or molybdenum. Therefore, the semiconductor substrate, which is the object to be processed, preferably has a portion composed of at least one selected from the group consisting of ruthenium, molybdenum, ruthenium alloys and molybdenum alloys. Hereinafter, the polishing method according to this embodiment will be described in detail with reference to FIGS. 1 to 4. FIG.

Examples of a semiconductor substrate having a portion composed of at least one selected from the group consisting of ruthenium, molybdenum, ruthenium alloys and molybdenum alloys include an object 100 to be processed as shown in FIG. FIG. 1 shows a cross-sectional view schematically showing an object 100 to be processed. The object to be processed 100 is manufactured through the following steps (1) to (4).

(1) First, as shown in FIG. 1, a substrate 10 is prepared. The substrate 10 may be composed of, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional devices such as transistors (not shown) may be formed on the substrate 10 . Next, a silicon oxide film 12, which is an insulating film, is formed on the substrate 10 by thermal oxidation.

(2) Next, the silicon oxide film 12 is patterned. Using the obtained pattern as a mask, a wiring trench 14 is formed in the silicon oxide film 12 by photolithography.

(3) Next, a ruthenium-containing film 16 is formed on the surface of the silicon oxide film 12 and the inner wall surface of the wiring trench 14 . The ruthenium-containing film 16 can be formed, for example, by chemical vapor deposition (CVD) using a ruthenium precursor, atomic layer deposition (ALD), or physical vapor deposition (PVD) such as sputtering. Incidentally, in this step, a molybdenum-containing film may be formed instead of the ruthenium-containing film 16 . A molybdenum-containing film can be formed, for example, by chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a molybdenum precursor, or physical vapor deposition (PVD) such as sputtering.

(4) Next, a copper film 18 having a film thickness of 10,000 to 15,000 Å ("Å" means 0.1 nm) is deposited by chemical vapor deposition or electroplating. As the material of the copper film 18, not only high-purity copper but also an alloy containing copper can be used. The copper content in the copper-containing alloy is preferably 95% by mass or more.

Then, the first polishing process for the object 100 to be processed is performed. FIG. 2 is a cross-sectional view schematically showing the object to be processed 100 at the end of the first polishing step. As shown in FIG. 2, in the first polishing step, the copper film 18 is polished using a chemical mechanical polishing composition for copper films until the ruthenium-containing film 16 (or molybdenum-containing film) is exposed. Examples of the chemical mechanical polishing composition for copper films include the chemical mechanical polishing aqueous dispersion described in JP-A-2010-153790.

Then, the second polishing process for the object 100 to be processed is performed. FIG. 3 is a cross-sectional view schematically showing the object to be processed 100 at the end of the second polishing step. As shown in FIG. 3, in the second polishing step, the chemical mechanical polishing composition of the present invention is used to partially polish the ruthenium-containing film 16 (or molybdenum-containing film), the copper film 18, and the silicon oxide film 12. do.

For the first polishing process and the second polishing process, for example, a polishing apparatus 200 as shown in FIG. 4 can be used. FIG. 4 is a perspective view schematically showing the polishing apparatus 200. As shown in FIG. In the first polishing process and the second polishing process, a slurry (chemical mechanical polishing composition) 44 is supplied from a slurry supply nozzle 42, and a semiconductor substrate 50 is polished while rotating a turntable 48 on which a polishing pad 46 is attached. is brought into contact with the carrier head 52 holding the . 4 also shows the water supply nozzle 54 and the dresser 56. As shown in FIG.

The material of the polishing pad 46 may be any of foamed polyurethane type, non-woven fabric type, and suede type, but is preferably foamed polyurethane type.

The polishing load of the carrier head 52 can be selected within the range of 0.7-70 psi, preferably 1.5-35 psi. Also, the rotation speed of the turntable 48 and the carrier head 52 can be appropriately selected within the range of 10 to 400 rpm, preferably 30 to 150 rpm. The lower limit of the flow rate of the chemical mechanical polishing composition supplied from the slurry supply nozzle 42 is 15 mL/min, preferably 50 mL/min, and the upper limit of the flow rate is 400 mL/min, preferably 300 mL/min. minutes.

Examples of commercially available polishing devices include models "EPO-112" and "F-REX300SII" manufactured by Ebara Corporation; models "LGP-510" and "LGP-552" manufactured by Lapmaster SFT; model "LGP-552" manufactured by Applied Materials; Mirra", "Reflexion"; Model "POLI-400L" manufactured by G&P TECHNOLOGY; Model "Reflexion LK" manufactured by AMAT.

3. Examples Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples. "Parts" and "%" in the examples are based on mass unless otherwise specified.

3.1. Preparation of silica particle aqueous dispersion 3.1.1. Preparation of Aqueous Dispersion A To 2000 g of PL-3 (19.5% colloidal silica dispersion manufactured by Fuso Chemical Industry Co., Ltd.) was adjusted to pH 9 by adding 25% aqueous ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.). After that, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise and stirred at 60° C. for 2 hours. After that, 50 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and refluxed for 8 hours under normal pressure to form cocoon-shaped silica particles surface-modified with sulfo groups having an average secondary particle diameter of 58 nm in terms of volume. A water dispersion A containing was obtained. The volume-equivalent average secondary particle size of each silica particle in water dispersions A to I was measured by a particle size distribution analyzer (manufactured by Malvern, model "Zetasizer Ultra").

3.1.2. Preparation of Water Dispersion B 2000 g of PL-3 (19.5% colloidal silica dispersion manufactured by Fuso Chemical Industry Co., Ltd.) was heated to 60°C. After that, 15.5 g of (3-triethoxysilyl) propylsuccinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was further stirred at 60°C for 4 hours. An aqueous dispersion B containing modified cocoon-shaped silica particles was obtained.

3.1.3. Preparation of water dispersion C A mixture of 70 g of methanol and 11.3 g of 3-aminopropyltriethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion). It was added dropwise to 2000 g and refluxed under normal pressure for 2 hours. After that, pure water was added dropwise while keeping the volume constant, and when the tower top temperature reached 100 ° C., the drop of pure water was terminated, and the surface was modified with amino groups having an average secondary particle diameter of 56 nm in terms of volume. An aqueous dispersion C containing cocoon-shaped silica particles was obtained.

3.1.4. Preparation of Aqueous Dispersion D To 1950 g of PL-2L (manufactured by Fuso Chemical Industry Co., Ltd., 20% colloidal silica dispersion), 25% aqueous ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added to adjust the pH to 9. After that, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise and stirred at 60° C. for 2 hours. After that, 50 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is added and refluxed for 8 hours under normal pressure to form spherical silica particles surface-modified with sulfo groups having an average secondary particle diameter of 23 nm in terms of volume. A water dispersion D containing

3.1.5. Preparation of aqueous dispersion E PL-3 (19.5% colloidal silica dispersion manufactured by Fuso Chemical Industry Co., Ltd.) as it is, an aqueous dispersion containing unmodified silica particles having an average secondary particle diameter of 60 nm in terms of volume used as E.

3.1.6. Preparation of Aqueous Dispersion F To 3250 g of PL-1 (12% colloidal silica dispersion manufactured by Fuso Chemical Industry Co., Ltd.) was adjusted to pH 9 by adding 25% aqueous ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.). After that, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise, and the mixture was stirred at 60° C. for 2 hours. Then, 50 g of hydrogen peroxide (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) is added, refluxed for 8 hours under normal pressure, and water containing silica particles surface-modified with sulfo groups having an average secondary particle diameter of 38 nm in terms of volume. Dispersion F was obtained.

3.1.7. Preparation of Water Dispersion G Silica particles were prepared according to Example 1 described in JP-A-2004-315300 to obtain a colloidal silica particle dispersion having a silica concentration of 4% by mass and an average secondary particle diameter of 7 nm in terms of volume. rice field. Subsequently, 25% aqueous ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added to 6510 g of the resulting colloidal silica particle dispersion to adjust the pH to 9. After that, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise and stirred at 60° C. for 2 hours. After that, 50 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, refluxed for 8 hours under normal pressure, and a water dispersion containing silica particles surface-modified with a sulfo group having an average secondary particle diameter of 7 nm in terms of volume. Got body G.

3.1.8. Preparation of Aqueous Dispersion H Silica particles were prepared according to Comparative Example 1 described in WO 2008/072637 to obtain a silica particle dispersion having a silica concentration of 29% by mass and an average secondary particle diameter of 22 nm. Subsequently, 25% aqueous ammonia (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added to 1,350 g of the obtained silica particle dispersion to adjust the pH to 9. After that, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise and stirred at 60° C. for 2 hours. After that, 50 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, refluxed for 8 hours under normal pressure, and a water dispersion containing silica particles surface-modified with a sulfo group having an average secondary particle diameter of 23 nm in terms of volume. Got body H.

3.1.9. Preparation of Water Dispersion I Silica particles were prepared according to Example 1 described in JP-A-2004-315300 to obtain a colloidal silica particle dispersion having a silica concentration of 4% by mass and an average secondary particle diameter of 7 nm. After that, 6510 g of the resulting colloidal silica particle dispersion was heated to 60°C. After that, 15.5 g of (3-triethoxysilyl) propylsuccinic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added, and the mixture was further stirred at 60°C for 4 hours. An aqueous dispersion I containing modified silica particles was obtained.

3.2. Preparation of Component (D) 3.2.1. Preparation of lauryliminodipropionate As alkylamines, 3.6 g (19.5 mmol) of laurylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5.7 g (52.9 mmol) of 3-chloropropionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were , 5.0 mL of water, and 32 mL of ethanol (manufactured by Kanto Chemical Co., Ltd.), and stirred under reflux for 6 hours. During this reflux stirring, 7.8 mL of potassium hydroxide aqueous solution (5.0 mol/L) prepared from potassium hydroxide (manufactured by Kanto Chemical Co., Ltd.) was added to adjust the pH. The solution was then cooled to 4° C. to form a precipitate. After washing the generated precipitate with ethanol, it was filtered and dried under reduced pressure to collect a solid to obtain lauryl iminodipropionate.

3.2.2. Preparation of myristyliminodipropionate Other than using 4.2 g (19.5 mmol) of myristylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as the alkylamine, the above "3.2.1. Preparation of lauryliminodipropionate ” to obtain myristyl iminodipropionate.

3.3. Preparation of chemical mechanical polishing composition Each component was mixed so as to have the composition shown in Tables 1 to 5, and a potassium hydroxide aqueous solution (manufactured by Kanto Kagaku Co., Ltd., product name "48% potassium hydroxide aqueous solution") and phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "phosphoric acid") or nitric acid (manufactured by Kanto Chemical Co., Ltd., trade name "nitric acid 1.38") are required. Pure water was added so that the total amount of all components was 100% by mass, and the chemical mechanical polishing compositions of each example and each comparative example were prepared. For each chemical mechanical polishing composition thus obtained, the zeta potential of abrasive grains was measured using a zeta potential measuring device (manufactured by Dispersion Technology Inc., model "DT300"). Tables 1 to 5 show the results. shown together.

3.4. Evaluation method 3.4.1. Polishing rate evaluation Using the chemical mechanical polishing composition prepared above, a 12-inch diameter wafer with a 100 nm ruthenium film and a 12-inch diameter wafer with a 500 nm molybdenum film were subjected to a chemical mechanical polishing test under the following conditions. did
(polishing conditions)
・Polishing device: Model “F-REX300SII” manufactured by Ebara Corporation
・Polishing pad: “Porous polyurethane pad; Optivision 9500 CMP Polishing pad” manufactured by DuPont
・Chemical mechanical polishing composition supply rate: 250 mL/min ・Surface plate rotation speed: 100 rpm
・Head rotation speed: 90 rpm
・Head pressing pressure: 2 psi
・Polishing time: 60 seconds ・Polishing rate (nm/min) = (thickness of film before polishing (nm) - thickness of film after polishing (nm))/polishing time (min)

The thicknesses of the ruthenium film and the molybdenum film are measured by a direct current four-probe method using a resistivity measuring device (manufactured by KLA-Tencor, model "RS-100"). It was calculated from the resistivity by the following formula.
・Thickness of ruthenium film (nm)=[volume resistivity of ruthenium film (Ω·m)÷sheet resistance value (Ω/sq)]×10 ⁹
・Thickness of molybdenum film (nm) = [Volume resistivity of molybdenum film (Ω·m)/Sheet resistance value (Ω/sq)] × 10 ⁹

The evaluation criteria for the polishing rate of the ruthenium film are as follows. Tables 1 to 3 also show the evaluation results of the polishing rate of the ruthenium film.
(Evaluation criteria)
A: When the polishing rate was 100 nm/min or more, it was judged to be very good.
B: When the polishing rate was 50 nm/min or more and less than 100 nm/min, it was judged to be good because it could be put to practical use.
C: When the polishing rate was less than 50 nm/min, the polishing rate was so low that it was difficult to put into practical use, so it was judged to be unsatisfactory.

The evaluation criteria for the molybdenum film polishing rate are as follows. Tables 4 and 5 also show the evaluation results of the molybdenum film polishing rate.
(Evaluation criteria)
A: When the polishing rate was 100 nm/min or more, it was judged to be very good.
B: When the polishing rate was less than 100 nm/min, the polishing rate was so low that it was difficult to put into practical use, so it was judged to be defective.

3.4.2. Etching Rate Evaluation The chemical mechanical polishing composition prepared above was heated to 60° C., and a wafer piece with a 100 nm ruthenium film or a wafer piece with a 200 nm molybdenum film cut to 30 mm×10 mm was immersed for 5 minutes. After that, the wafer piece was taken out and washed with running water, and the thickness of the ruthenium film or molybdenum film was measured by the same method as in "3.4.1. Polishing rate evaluation". Then, the etching rate was calculated from the change in thickness of the ruthenium film or molybdenum film before and after the immersion using the following formula.
Etching rate of ruthenium film (nm/min)=(thickness of ruthenium film before etching (nm)−thickness of ruthenium film after etching (nm))/etching time (min)
Molybdenum film etching rate (nm/min) = (thickness of molybdenum film before etching (nm) - thickness of molybdenum film after etching (nm))/etching time (min)

The evaluation criteria for the etching rate of the ruthenium film are as follows. Tables 1 to 3 also show the evaluation results of the etching rate of the ruthenium film.
(Evaluation criteria)
A: When the etching rate was less than 1.5 nm/min, it was judged to be very good.
B: When the etching rate was 1.5 nm/min or more and less than 3 nm/min, it was judged to be good because it could be put to practical use.
C: When the etching rate was 3 nm/min or more, the etching rate was so high that it was difficult to put into practical use, so it was judged to be defective.

The evaluation criteria for the etching rate of the molybdenum film are as follows. Tables 4 and 5 also show the evaluation results of the etching rate of the molybdenum film.
(Evaluation criteria)
A: When the etching rate was less than 20 nm/min, it was judged to be very good.
B: When the etching rate was 20 nm/min or more, the etching rate was so high that it was difficult to put into practical use, so it was judged to be unsatisfactory.

3.4.3. Storage stability evaluation After storing the chemical mechanical polishing composition prepared above in a constant temperature storage at 20°C for 3 days or 7 days, a wafer with a 12-inch diameter ruthenium film of 100 nm or a 12-inch diameter molybdenum film with a 500 nm film was prepared. Using a wafer as an object to be polished, a chemical mechanical polishing test was conducted under the same polishing conditions as in the above "3.4.1. Polishing rate evaluation". Then, the fluctuation rate of the polishing rate of the ruthenium film before and after storage was calculated by the following formula.
Variation rate (%) = | ((polishing rate calculated in the section “3.4.1. Polishing rate evaluation”) - (polishing rate when using chemical mechanical polishing composition after storage))/ (Polishing speed calculated in the section “3.4.1. Polishing speed evaluation”)×100|

The evaluation criteria for the volatility are as follows. Tables 1 to 5 also show the storage stability evaluation results of the chemical mechanical polishing composition.
(Evaluation criteria)
A: A polishing rate variation of less than 10% after 7 days of storage was judged to be very good.
B: The rate of change in polishing rate after 3 days of storage is less than 10%, but when the rate of change in polishing rate after 7 days of storage is 10% or more, it can be put to practical use, which is favorable. I decided.
C: If the fluctuation rate of the polishing rate after 3 days of storage was 10% or more, it was judged to be unsatisfactory because it was difficult to put into practical use.

3.5. Evaluation Results Tables 1 to 5 show the composition of the chemical mechanical polishing composition used in each example and each comparative example and each evaluation result.

The following products or reagents were used for each component in Tables 1 to 5 above.
<Component (A)>
Aqueous dispersions A to I: Aqueous dispersions A to I prepared in the above section "3.1. Preparation of silica particle aqueous dispersion"
<Component (D)>
· N- (phosphonomethyl) iminodiacetic acid: manufactured by Sigma-Aldrich, trade name "N- (phosphonomethyl) iminodiacetic acid hydrate"
・ Hydroxyethyliminodiacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “N-(2-Hydroxyethyl) iminodiacetic Acid”
· N- (2-Carboxyethyl) iminodiacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N- (2-Carboxyethyl) iminodiacetic Acid"
・ Nitrilotriacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Nitrilotriacetic Acid"
3,3′,3″-nitrilotripropionic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “3,3′,3″-Nitrilopropionic Acid”
- Ethylenediaminetetraacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Ethylenediaminetetraacetic Acid"
- Lauryl imino dipropionate: Lauryl iminodipropionate prepared in the above section "3.2. Preparation of component (D)" - Myristyl iminodipropionate: Above "3.2. Component (D) Preparation of "myristyliminodipropionate/dodecylaminoethylaminoethylglycine prepared in section: Sanyo Chemical Industries, Ltd., trade name "Lebon S"
<Component (B)>
・H ₅ IO ₆ (periodic acid): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name “orthoperiodic acid”
・KClO (potassium hypochlorite): manufactured by Kanto Chemical Co., Ltd., trade name “potassium hypochlorite solution”
- KClO ₂ (potassium chlorite): manufactured by Angene, trade name "Potassium Chlorite"
・ NaBrO (sodium hypobromite): manufactured by Kanto Chemical Co., Ltd., trade name “sodium hypobromite”
<Component (C)>
・ Hydrogen peroxide: Fujifilm Wako Pure Chemical Co., Ltd., 30% aqueous solution <Other ingredients>
2-phosphonobutane-1,2,4-tricarboxylic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "2-Phosphonobutane-1,2,4-tricarboxylic Acid (ca. 50% in Water)"
- N,N,N',N'-tetramethylethylenediamine: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N,N,N',N'-Tetramethylethylenediamine"
・ 1-Hydroxyethylidene-1,1-diphosphonic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “1-Hydroxyethane-1,1-diphosphonic Acid (ca. 60% in Water, ca. 4.2 mol / L)”
Ethylenediaminetetra (methylenephosphonic acid): manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N,N,N',N'-Ethylenediaminetetrakis (methylenephosphonic Acid)"
・ Malonic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Malonic Acid"
・ Phthalic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “Phthalic Acid”
・ Citric acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Citric Acid"
・ Adipic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Adipic Acid"
・ L-tartaric acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “L-(+)-Tartaric Acid”
・ Iron nitrate nonahydrate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name “Iron (III) nitrate nonahydrate”
・ Iron citrate hydrate, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., trade name “Iron (III) citrate n hydrate”
・ Acetylacetone iron, manufactured by Tokyo Chemical Industry Co., Ltd., trade name “Tris (2,4-pentanedionato) iron (III)”
・ Ethyltrimethylammonium hydroxide, manufactured by SACHEM, trade name “Envure SE ^TM 3330”
・ Benzyltrimethylammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Benzyltrimethylammonium Hydroxide (40% in Water)"
・ Trimethyladamantyl ammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N, N, N-Trimethyl-1-adamantyl ammonium Hydroxide (25% in Water)"
・ Tetraethylammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd., trade name “Tetraethylammonium Hydroxide (10% in Water)”
・ Tetrabutylammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd., trade name “Tetrabutylammonium Hydroxide (40% in Water)”

According to the chemical mechanical polishing compositions of Examples 1 to 23, in which the component (A) and the component (D) having specific functional groups are used in combination, the component (A) is easily adsorbed to the ruthenium film or the molybdenum film. In addition, component (D) adsorbs to the surface of the ruthenium and molybdenum films to form a protective film, thereby suppressing excessive corrosion of the ruthenium and molybdenum films. I know you can. Further, by using the component (A) having a specific functional group, the repulsive force between the abrasive grains in the chemical mechanical polishing composition is increased, and the agglomeration of the abrasive grains is suppressed, thereby improving the storage stability. I understand.

On the other hand, according to the chemical mechanical polishing compositions of Comparative Examples 1 to 2 and 8 to 12 containing abrasive grains having no specific functional group, the polishing rate of the ruthenium film and the molybdenum film was lowered, and it was put to practical use. It turns out that it is difficult to In addition, according to the chemical mechanical polishing compositions of Comparative Examples 3 to 7 using alternative components for component (D), when the object to be polished was a ruthenium film, corrosion of the ruthenium film could not be suppressed, or ruthenium In some cases, the corrosion of the film can be suppressed to some extent, but the reaction of the component with the specific anion species significantly deteriorates the storage stability, making it difficult to put it to practical use. Furthermore, according to the chemical mechanical polishing compositions of Comparative Examples 10 to 14, which do not contain the component (D), when the object to be polished is a molybdenum film, the polishing rate of the molybdenum film is remarkably low. .

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same function, method, and result, or configurations that have the same purpose and effect). Moreover, the present invention includes configurations in which non-essential portions of the configurations described in the embodiments are replaced. Moreover, the present invention includes a configuration that achieves the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the present invention includes configurations obtained by adding known techniques to the configurations described in the embodiments.

DESCRIPTION OF SYMBOLS 10... Substrate, 12... Silicon oxide film, 14... Wiring groove, 16... Ruthenium-containing film, 18... Copper film, 42... Slurry supply nozzle, 44... Slurry (chemical mechanical polishing composition), 46... Polishing pad , 48... Turntable, 50... Semiconductor substrate, 52... Carrier head, 54... Water supply nozzle, 56... Dresser, 100... Object to be processed, 200... Polishing apparatus

Claims

Abrasive grains (A);
containing a compound (D) having at least one functional group selected from the group consisting of an amino group and salts thereof and at least one functional group selected from the group consisting of a carboxy group and salts thereof; death,
A chemical mechanical polishing composition, wherein the abrasive grains (A) have at least one functional group among the functional groups represented by the following general formulas (1) to (4).
- SO 3 - M + (1)
- COO - M + (2)
(In formulas (1) and (2) above, M + represents a monovalent cation.)
-NR 1 R 2 (3)
-N + R 1 R 2 R 3 M ( 4)
(In formulas (3) and (4) above, R 1 , R 2 and R 3 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. M − represents an anion.)
The chemical mechanical polishing composition according to claim 1, wherein the content of the compound (D) is 0.005 to 5% by mass.
The chemical mechanical polishing composition according to claim 1 or 2, wherein the absolute value of the zeta potential of the abrasive grains (A) in the chemical mechanical polishing composition is 10 mV or more.
The chemical mechanical polishing composition according to any one of claims 1 to 3, which has a pH of 6 or more and 12 or less.
The chemical mechanical polishing composition according to any one of claims 1 to 3, which has a pH of 1.5 or more and 4 or less.
The chemical mechanical polishing composition according to claim 5, wherein the abrasive grains (A) in the chemical mechanical polishing composition have an average secondary particle size of 5 nm or more and 70 nm or less.
A polishing method comprising the step of polishing a semiconductor substrate using the chemical mechanical polishing composition according to any one of claims 1 to 6.
The polishing method according to claim 7, wherein the semiconductor substrate has a portion composed of at least one selected from the group consisting of ruthenium, molybdenum, ruthenium alloys and molybdenum alloys.