TW202336182A - Composition for chemical mechanical polishing and polishing method - Google Patents

Abstract

To provide a composition for chemical mechanical polishing that makes it possible to polish a molybdenum film and a silicon oxide film at a stable polishing rate and to inhibit corrosion of the molybdenum film and generation of defects in the silicon oxide film. The composition for chemical mechanical polishing contains abrasive grains and an iron (III) compound, where the abrasive grains have at least one of functional groups represented by the general formula (1), -SO3-M+, and the general formula (2), -COO-M+. In the formulas (1) and (2), M+ represents a monovalent cation.

Description

Chemical mechanical polishing composition and polishing method

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

As the manufacturing technology of semiconductor integrated circuits improves, 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 elements has become more stringent, and chemical mechanical polishing (CMP) has become an indispensable technology in the manufacturing process of semiconductor elements. .

Tungsten, which is excellent in embedding properties, is often used in through-holes for electrically connecting wirings in the vertical direction of semiconductor substrates manufactured by CMP. As a chemical mechanical polishing composition for polishing a tungsten film, a polishing composition containing an oxidizing agent such as hydrogen peroxide, an iron catalyst such as ferric nitrate, and abrasive grains such as silica has been proposed (see, for example, patent Document 1). In addition, in recent years, chemical mechanical polishing compositions for polishing molybdenum films using molybdenum instead of tungsten have been studied in terms of low hardness compared to tungsten and ease of processing (for example, see Patent Document 2 ). [Prior art documents] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2008-503875 [Patent Document 2] International Publication No. 2013/188296

[Problem to be solved by the invention]

In CMP for forming a via hole using molybdenum, it is necessary to polish and planarize the embedded molybdenum film and the surrounding silicon oxide film in the same step. In order to achieve this, there is a demand for a chemical mechanical polishing composition that can polish the molybdenum film and the silicon oxide film at a stable polishing rate while suppressing the corrosion of the molybdenum film and the occurrence of defects in the silicon oxide film.

Several aspects of the present invention provide a chemical mechanical polishing composition that can polish a molybdenum film and a silicon oxide film at a stable polishing speed, and can suppress corrosion of the molybdenum film and the generation of defects in the silicon oxide film. [Means to solve the problem]

This invention is made in order to solve at least a part of the said subject, and can be implemented as any of the following forms.

One aspect of the chemical mechanical polishing composition of the present invention contains: abrasive grains (A) and an iron (III) compound (B); the abrasive grains (A) have a functional group represented by the following general formula (1) and at least one functional group among the functional groups represented by the following general formula (2). -SO ₃ ^- M ⁺・・・・・(1) -COO ^- M ⁺・・・・(2) (In the above formula (1) and the above formula (2), M ⁺ represents a monovalent cation)

In one form of the chemical mechanical polishing composition, It may further contain a compound (C) having at least one functional group selected from the group consisting of an amine group and its salts, a group selected from the group consisting of a carboxyl group, a sulfo group, and salts thereof. At least one functional group in the group.

In any form of the chemical mechanical polishing composition, The average secondary particle diameter of the abrasive grains (A) in the chemical mechanical polishing composition may be 5 nm or more and 100 nm or less.

In any form of the chemical mechanical polishing composition, The degree of association of the abrasive grains (A) in the chemical mechanical polishing composition may be 1.0 or more and 2.0 or less.

In any form of the chemical mechanical polishing composition, The other potential of the abrasive particles (A) in the chemical mechanical polishing composition may be less than 0 mV.

In any form of the chemical mechanical polishing composition, The pH may be 1 or more and 6 or less.

One form of the grinding method of the present invention includes: The step of polishing a semiconductor substrate using any of the chemical mechanical polishing compositions.

In one aspect of the polishing method, The semiconductor substrate may include a portion made of at least one selected from the group consisting of molybdenum and molybdenum alloys. [Effects of the invention]

By using the chemical mechanical polishing composition of the present invention, the corrosion of the molybdenum film and the generation of defects in the silicon oxide film can be suppressed, and at the same time, the semiconductor substrate including the molybdenum film and the silicon oxide film can be polished at a stable polishing speed.

Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, the present invention is not limited to the following embodiments, but also includes various modifications implemented within the scope that does not change the gist of the present invention.

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

1. Chemical mechanical polishing composition A chemical mechanical polishing composition according to one embodiment of the present invention contains: abrasive grains (A) (also referred to as "component (A)" in this specification), and an iron (III) compound ( B) (also referred to as "component (B)" in this specification), the abrasive grain (A) has a functional group represented by the following general formula (1) and a functional group represented by the following general formula (2) at least one functional group in. -SO ₃ ^- M ⁺・・・・・(1) -COO ^- M ⁺・・・・(2) (In the above formula (1) and the above formula (2), M ⁺ represents a monovalent cation)

Hereinafter, each component contained in the chemical mechanical polishing composition of this embodiment will be described in detail.

1.1.Ingredients (A) The composition for chemical mechanical polishing of this embodiment contains abrasive grains (A). Component (A) may be either inorganic particles or organic particles, and inorganic particles are preferred. Examples of inorganic particles include inorganic oxide particles such as silica, cerium oxide, alumina, zirconium oxide, and titanium dioxide. Among these, silica particles are preferred. Examples of silica particles include fumed silica, colloidal silica, and the like, and colloidal silica is preferred.

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

The beta potential of component (A) in the composition for chemical mechanical polishing is preferably a negative beta potential, that is, less than 0 mV, more preferably -10 mV or less, and particularly preferably -15 mV or less. If the beta potential of component (A) is within the above range, the aggregation of particles can be effectively prevented by the electrostatic repulsive force between abrasive particles. Therefore, the storage stability of the chemical mechanical polishing composition is improved, and the chemical mechanical polishing composition can be more polished. Semiconductor substrates including molybdenum films and silicon oxide films are polished at a stable polishing speed. Furthermore, examples of zeta potential measuring devices include: "ELSZ-2000ZS" manufactured by Otsuka Electronics Co., Ltd., "Zetasizer Ultra" manufactured by Malvern Corporation, and American Dispersion Technology "DT300" manufactured by Dispersion Technology Inc., etc.

At least part of the surface of component (A) has at least one of a functional group represented by the following general formula (1) and a functional group represented by the following general formula (2) (hereinafter also referred to as "specific functional group") Functional group. -SO ₃ ^- M ⁺・・・・・(1) -COO ^- M ⁺・・・・(2) (In the above formula (1) and the above formula (2), M ⁺ represents a monovalent cation)

Compared with abrasive grains whose surface is not surface-modified with a specific functional group, an abrasive grain whose surface is at least partially modified by a specific functional group has a larger absolute value of the other potential, thereby increasing the electrostatic repulsive force between the abrasive grains. As a result, the dispersibility of the abrasive grains in the chemical mechanical polishing composition is improved, so that the semiconductor substrate including the molybdenum film and the silicon oxide film can be polished at a stable polishing speed while reducing the occurrence of polishing damage or dents.

In the general formula (1), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ . That is, the functional group represented by the general formula (1) may be renamed as "at least one functional group selected from the group consisting of a sulfo group and its salts." Here, the "salt of a sulfo group" refers to a functional group obtained by replacing the hydrogen ions contained in the sulfo group (-SO ₃ H) with monovalent cations such as Li ⁺ , Na ⁺ , K ⁺ , or NH ₄ ⁺ . The component (A) having the functional group represented by the general formula (1) is an abrasive grain having the functional group represented by the general formula (1) fixed to its surface via a covalent bond, and is not included in its surface. Abrasive grains to which a compound having a functional group represented by the general formula (1) is physically or ionically adsorbed.

The component (A) having the functional group represented by the general formula (1) can be produced as follows. First, by thoroughly stirring the silica and the silane coupling agent containing thiol groups prepared by a known method in an acidic medium, the silane coupling agent containing thiol groups can be covalently bonded to the surface of the silica. Here, examples of the mercapto group-containing silane coupling agent include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like. Next, an appropriate amount of hydrogen peroxide is added and the mixture is allowed to stand sufficiently to obtain a component (A) having a functional group represented by the general formula (1).

The component (A) having the functional group represented by the general formula (1) has a negative potential in the chemical mechanical polishing composition, and its negative potential is preferably less than 0 mV, more preferably -10 mV. below, the best value is below -15 mV. If the beta potential of component (A) is within the above range, the aggregation of particles may be effectively prevented by the electrostatic repulsive force between abrasive grains, and the molybdenum film and the silicon oxide film may be polished at a more stable polishing speed. The semiconductor substrate is polished. Furthermore, the device described above can be used as a beta potential measuring device. The beta potential of the component (A) having the functional group represented by the general formula (1) can be adjusted by appropriately increasing or decreasing the amount of the thiol group-containing silane coupling agent or the like added.

In the general formula (2), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ . That is, the functional group represented by the general formula (2) may be renamed as "at least one functional group selected from the group consisting of a carboxyl group and its salt". Here, the "salt of a carboxyl group" refers to a functional group in which a hydrogen ion contained in a carboxyl group (-COOH) is replaced with a monovalent cation such as Li ⁺ , Na ⁺ , K ⁺ , or NH ₄ ⁺ . 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, and is not included in its surface. Abrasive grains to which a compound having a functional group represented by the general formula (2) is physically or ionically adsorbed.

The component (A) having the functional group represented by the general formula (2) can be produced as follows. First, the silica made by a known method and the silane coupling agent containing carboxylic acid anhydride are fully stirred in an alkaline medium, so that the silane coupling agent containing carboxylic acid anhydride is covalently bonded to the surface of the abrasive grains, thereby obtaining Abrasive grains having a functional group represented by the general formula (2). Here, examples of the carboxylic acid anhydride-containing silane coupling agent include 3-(triethoxysilyl)propylsuccinic anhydride and the like.

The other potential of the component (A) having the functional group represented by the general formula (2) is a negative potential in the chemical mechanical polishing composition, and its negative potential is preferably less than 0 mV, more preferably -10 mV. below, the best value is below -15 mV. If the beta potential of component (A) is within the above range, the aggregation of particles may be effectively prevented by the electrostatic repulsive force between abrasive grains, and the molybdenum film and the silicon oxide film may be polished at a more stable polishing speed. The semiconductor substrate is polished. Furthermore, the device described above can be used as a beta potential measuring device. The beta 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 carboxylic acid anhydride-containing silane coupling agent or the like added.

The average secondary particle diameter of component (A) in the chemical mechanical polishing composition is preferably 5 nm or more, more preferably 7 nm or more, and particularly preferably 10 nm or more. The average secondary particle diameter of component (A) in the chemical mechanical polishing composition is preferably 100 nm or less, more preferably 70 nm or less, and particularly preferably 60 nm or less. If the average secondary particle size of component (A) is within the above range, the mechanical grinding performance will be reduced due to the small particle size, but the surface free energy will be increased, thereby improving the reactivity with molybdenum or silicon oxide, so more stable grinding can be achieved. The semiconductor substrate containing the molybdenum film and the silicon oxide film is polished at a polishing speed, and a composition for chemical mechanical polishing that is excellent in stability and does not cause sedimentation or separation of particles can be obtained. In addition, the average secondary particle diameter of the component (A) in the composition for chemical mechanical polishing is a volume-based average particle diameter that can be measured by a particle size distribution measuring device using a dynamic light scattering method. An example of such a particle size distribution measuring device is "Zetasizer Ultra" manufactured by Malvern Corporation.

The average primary particle diameter of component (A) in the chemical mechanical polishing composition is preferably 5 nm or more, more preferably 7 nm or more, and particularly preferably 10 nm or more. The average primary particle diameter of component (A) in the chemical mechanical polishing composition is preferably 100 nm or less, more preferably 70 nm or less, and particularly preferably 60 nm or less. In addition, the average primary particle diameter of the component (A) in the chemical mechanical polishing composition can be calculated by observing with a transmission electron microscope and determining the average value of 50 particle diameters of the component (A).

From the average secondary particle diameter and the average primary particle diameter measured as above, the degree of association, which is an index indicating the degree of aggregation of component (A) in the chemical mechanical polishing composition, can be calculated using the following calculation formula. Degree of association = (average secondary particle size (nm))/(average primary particle size (nm))

The degree of association of component (A) in the chemical mechanical polishing composition is preferably 1.0 or more, more preferably 1.01 or more. The degree of association of component (A) in the chemical mechanical polishing composition is preferably 2.0 or less, more preferably 1.7 or less, and particularly preferably 1.6 or less. If the degree of association of component (A) is within the above range, the aggregation of component (A) is suppressed and dispersed in the chemical mechanical polishing composition, and the surface free energy of the particles increases, thereby causing reaction with molybdenum or silicon oxide. Due to improved performance, semiconductor substrates including molybdenum films and silicon oxide films can sometimes be polished at a more stable polishing speed.

When the total mass of the chemical mechanical polishing composition is 100 mass%, the content of component (A) in the chemical mechanical polishing composition of this embodiment is preferably 0.1 mass% or more, more preferably 0.3 mass% Above, particularly preferably 0.5% by mass or more. When the total mass of the chemical mechanical polishing composition is 100 mass%, the content of component (A) in the chemical mechanical polishing composition of this embodiment is preferably 10 mass% or less, more preferably 8 mass% below, particularly preferably 6% by mass or less. When the content of component (A) is within the above range, the semiconductor substrate including the molybdenum film and the silicon oxide film can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may become good.

1.2.Ingredients (B) The chemical mechanical polishing composition of this embodiment contains an iron (III) compound (B). Component (B) has the function of oxidizing the surface of the molybdenum film to form a fragile modified layer and promoting polishing of the molybdenum film.

Component (B) may be either an organic acid iron (III) salt or an inorganic acid iron (III) salt as long as it has the above-described action. As component (B), a chelate compound of iron (III) ions is preferred.

Chelated compounds of iron (III) ions can be produced by reacting iron (III) ions with a chelating agent. When preparing the chemical mechanical polishing composition of this embodiment, a chelate compound of iron (III) ions can be added as component (B), or iron (III) ions and a chelating agent can be added separately to make these components in the composition. reaction to form chelated compounds of iron (III) ions.

The chelating agent is not particularly limited as long as it is a compound that can coordinate with iron (III) ions as a bidentate or higher ligand. For example, (poly)carboxylic acid, (poly)aminocarboxylic acid, Chelating agents such as (poly)oxycarboxylic acid, (poly)phosphonic acid, and their salts. Preferable examples of the chelating agent include: glycine, citric acid, tartaric acid, acetyl acetone, dihydroxyethylglycine, glycol ether diamine tetraacetic acid, and dicarboxymethylglutamic acid. , ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, 1,3-propanediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 1 , 3-diamino-2-hydroxypropanetetraacetic acid, hydroxyethyliminodiacetic acid; pyrophosphoric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, nitrogen tris(methylenephosphonic acid) ), 2-phosphonobutane-1,2,4-tricarboxylic acid, ethylenediaminetetrakis(methylenephosphonic acid); and their salts, etc. Among these, ethylenediaminetetraacetic acid is particularly preferred. These chelating agents may be used alone or in combination of two or more.

Furthermore, for example, a chemical mechanical polishing composition for polishing tungsten described in Japanese Patent Application Publication No. 2008-503875 uses an iron (III) compound, specifically iron (III) nitrate. However, iron (III) nitrate cannot be used in the chemical mechanical polishing composition of this embodiment. The reason is that if iron (III) nitrate is used, the surface of the molybdenum film will be excessively oxidized due to the action of nitrate ions, and corrosion of the molybdenum portion will easily occur. Therefore, it is preferable that the chemical mechanical polishing composition of this embodiment contains no nitrate ions as much as possible. The nitrate ion concentration in the chemical mechanical polishing composition of this embodiment is preferably 200 ppm or less, more preferably 190 ppm or less, and particularly preferably 180 ppm or less. Furthermore, even when the chemical mechanical polishing composition of the present embodiment contains nitrate ions, it is acceptable as long as it is 0.005 ppm or more. Even if it is 0.01 ppm or more, it is practically acceptable.

When the total mass of the chemical mechanical polishing composition is 100 mass%, the content of component (B) in the chemical mechanical polishing composition of this embodiment is preferably 0.001 mass% or more, more preferably 0.05 mass% Above, particularly preferably 0.01% by mass or more. When the total mass of the chemical mechanical polishing composition is 100 mass%, the content of component (B) in the chemical mechanical polishing composition of this embodiment is preferably 10 mass% or less, more preferably 5 mass% or less, preferably 1% by mass or less, and particularly preferably 0.5% by mass or less. If the content of component (B) is within the above range, the molybdenum film can be oxidized to promote polishing, and excessive reaction between molybdenum and anionic species can be prevented, thereby reducing the occurrence of corrosion of the molybdenum film.

The concentration of iron (III) ions in the chemical mechanical polishing composition of this embodiment is preferably 1 ppm or more, more preferably 3 ppm or more, and particularly preferably 5 ppm or more. The concentration of iron (III) ions in the chemical mechanical polishing composition of this embodiment is preferably 1000 ppm or less, more preferably 900 ppm or less, and particularly preferably 800 ppm or less. If the concentration of iron (III) ions in the chemical mechanical polishing composition of the present embodiment is within the above range, the molybdenum film can be oxidized to accelerate polishing, and excessive reaction between molybdenum and anionic species can be prevented. And reduce the occurrence of corrosion of molybdenum film.

1.3.Ingredients (C) The chemical mechanical polishing composition of this embodiment may contain compound (C) (also referred to as "component (C)" in this specification) having an amine group selected from the group consisting of its salts. and at least one functional group selected from the group consisting of carboxyl group, sulfo group, and salts thereof. Component (C) has the function of forming a protective film by being adsorbed on the surface of the molybdenum film, thereby reducing corrosion of the molybdenum portion.

Examples of the amino group and its salt include a functional group represented by the following general formula (3) or the following general formula (4). -NR ¹ R ²・^・・・・(3) -N ^{+ R 1} R ^{2 2} each independently represents a hydrogen atom, or a substituted or unsubstituted hydrocarbon group; X ^- represents an anion)

In the general formula (3) and the general formula (4), R ¹ and R ² each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, and R ¹ and R ² may be bonded to form a ring. structure.

The hydrocarbon group represented by R ¹ to R ² may be any one of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aromatic aliphatic hydrocarbon group, or an alicyclic hydrocarbon group. In addition, the aliphatic component of the aliphatic hydrocarbon group and the aromatic aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. Examples of these hydrocarbon groups include linear, branched, or cyclic alkyl groups, alkenyl groups, aralkyl groups, aryl groups, and the like.

As the alkyl group, a lower alkyl group having 1 to 6 carbon atoms is generally preferred, and a lower alkyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second-butyl, third-butyl, n-pentyl, isopentyl, Second pentyl group, third pentyl group, neopentyl group, n-hexyl group, isohexyl group, second hexyl group, third hexyl group, cyclopentyl group, cyclohexyl group, etc.

As the alkenyl group, a lower alkenyl group having 1 to 6 carbon atoms is generally preferred, and a lower alkenyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkenyl groups include vinyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, second butenyl, third butenyl, and the like.

As the aralkyl group, one having 7 to 12 carbon atoms is generally preferred. Examples of such aralkyl groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylhexyl, methylbenzyl, methylphenethyl, ethylbenzyl, and the like.

As the aryl group, one having 6 to 14 carbon atoms is generally preferred. 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, 3,5-xylyl, naphthyl, anthracenyl, etc.

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

Examples of carboxyl groups and salts thereof include functional groups represented by the following general formula (5). -COO ^- M ⁺・・・・・(5) (M ⁺ represents monovalent cation)

In the general formula (5), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

Examples of the sulfo group and its salt include functional groups represented by the following general formula (6). -SO ₃ ^- M ⁺・・・・・(6) (M ⁺ represents a monovalent cation)

In the general formula (6), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

Component (C) must have at least one functional group selected from the group consisting of an amine group and its salts, and at least one functional group selected from the group consisting of a carboxyl group, a sulfo group, and their salts. The structure is not particularly limited, but it is preferably a structure represented by the following general formula (7) or the following general formula (8). -N(R ³ COO ^- M ⁺ ) _n (R ⁴ ) _2-n・・・・・(7) -N(R ³ SO ₃ ^- M ⁺ ) _n (R ⁴ ) _2-n・・・・・(8) (In the formula (7) and the formula (8), R ³ represents a substituted or unsubstituted divalent hydrocarbon group; R ⁴ represents a hydrogen atom, or a substituted or unsubstituted hydrocarbon group; M ⁺ represents a monovalent cation; n represents an integer from 1 to 2)

In the general formula (7) and the general formula (8), examples of the divalent hydrocarbon group represented by R ³ include an alkanediyl group having 1 to 3 carbon atoms. In the general formula (7) and the general formula (8), examples of the hydrocarbon group represented by R ⁴ include those represented by R ¹ to R ² of the general formula (3) and the general formula (4). The exemplified hydrocarbon groups are the same. In the general formula (7) and the general formula (8), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄₊ ^.

Since the component (C) has the structure represented by the general formula (7) or the general formula (8), the component (C) is effectively coordinated on the surface of the molybdenum film, so the molybdenum sites can be reduced more effectively. of corrosion.

Examples of the component (C) include N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, and N-(2-carboxyethyl)imine. Diacetic acid, ethylenediaminetetraacetic acid, tetrasodium L-glutamic acid diacetate, glycine-N,N-bis(methylenephosphonic acid), 3,3',3''-nitrotripropyl Acid, octyl imino dipropionate, lauryl imino dipropionate, myristyl imino dipropionate, stearyl imino dipropionate, palmityl imino dipropionate Propionate, glycol ether diamine tetraacetic acid, hydroxyethyl ethylenediamine triacetic acid, 1,3-propanediamine-N,N,N',N'-tetraacetic acid, trisethylenetetraminehexaacetic acid , dihydroxyethylglycine, dodecylaminoethylaminoethylglycine, (S,S)-ethylenediamine disuccinic acid trihydrate, iminodiacetic acid, trans-1 , 2-Diaminocyclohexane-N,N,N',N'-tetraacetic acid hydrate, laurylamine propyl hydroxysulfobetaine, lauryl hydroxysulfobetaine, etc. These components (C) may be used individually by 1 type, and may be used in combination of 2 or more types.

When the total mass of the chemical mechanical polishing composition is 100 mass%, the content of component (C) in the chemical mechanical polishing composition of this embodiment is preferably 0.0005 mass% or more, more preferably 0.0008 mass% Above, particularly preferably 0.001% by mass or more. When the total mass of the chemical mechanical polishing composition is 100 mass %, the content of component (C) in the chemical mechanical polishing composition of this embodiment is preferably 5 mass % or less, more preferably 1 mass %. below, particularly preferably 0.1% by mass or less. If the content of component (C) is within the above range, corrosion of the molybdenum portion may be effectively reduced.

1.4. Other ingredients In addition to the above-mentioned components, the chemical mechanical polishing composition of this embodiment may also contain a liquid medium, a water-soluble polymer, a nitrogen-containing heterocyclic compound, a surfactant, an organic acid and its salt, an inorganic acid and Its salts, alkaline compounds, etc.

＜Liquid medium＞ The chemical mechanical polishing composition of this embodiment contains a liquid medium. Examples of the liquid medium include water, a mixed medium of water and alcohol, a mixed medium containing water and an organic solvent that is compatible with water, and the like. Among these, water or a mixed medium of water and alcohol is preferably used, and water is more preferably used. As a raw material of water, pure water can be preferably used. The liquid medium may be prepared as the remainder of each component.

＜Water-soluble polymer＞ The chemical mechanical polishing composition of this embodiment may contain a water-soluble polymer. Water-soluble polymers sometimes adsorb on the surface of the polished surface to reduce grinding friction, thereby reducing the occurrence of depressions in the polished surface.

Specific examples of water-soluble polymers include polycarboxylic acid, polystyrene sulfonic acid, polyacrylic acid, polymethacrylic acid, polyether, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene oxide. Amine, polyallylamine, hydroxyethyl cellulose, etc. These can be used individually by 1 type or in combination of 2 or more types.

The weight average molecular weight (Mw) of the water-soluble polymer is preferably from 10,000 to 1.5 million, more preferably from 40,000 to 1.2 million. Here, the “weight average molecular weight” 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 this embodiment contains a water-soluble polymer, when the total mass of the chemical mechanical polishing composition is 100 mass%, the content of the water-soluble polymer is preferably 0.001 mass%. or above, more preferably 0.002% by mass or more. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the water-soluble polymer is preferably 0.1% by mass or less, more preferably 0.01% by mass or less.

＜Nitrogen-containing heterocyclic compounds＞ Nitrogen-containing heterocyclic compounds refer to organic compounds having at least one nitrogen atom and containing at least one heterocyclic ring selected from a heterocyclic five-membered ring and a heterocyclic six-membered ring. Specific examples of the heterocyclic ring include heterocyclic five-membered rings such as pyrrole structure, imidazole structure, and triazole structure; heterocyclic six-membered rings such as pyridine structure, pyrimidine structure, pyridazine structure, and pyrazine structure. The heterocycles may also form condensed rings. Specific examples include: indole structure, isoindole structure, benzimidazole structure, benzotriazole structure, quinoline structure, isoquinoline structure, quinazoline structure, cinnoline structure, and phthalazine Structure, quinoxaline structure, acridine structure, etc. Among the heterocyclic compounds having such a structure, those having a pyridine structure, a quinoline structure, a benzimidazole structure, or 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, and benzisoquin pholine, purine, pteridine, triazole, triazolidine, benzotriazole, carboxybenzotriazole, and derivatives having these skeletons. Among these, at least one selected from the group consisting of benzotriazole and triazole is preferred. One type of these nitrogen-containing heterocyclic compounds may be used alone, or two or more types may be used in combination.

＜Surface active agent＞ 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; fluorinated surfactants such as perfluoroalkyl compounds; and the like. Examples of the cationic surfactant include aliphatic amine salts, aliphatic ammonium salts, and the like. Examples of the nonionic surfactant include nonionic surfactants having triple bonds such as acetylene glycol, acetylene glycol ethylene oxide adduct, and acetylene alcohol; polyethylene glycol type surfactants; and the like. These surfactants may be used alone or in combination of two or more.

＜Organic acids and their salts＞ The chemical mechanical polishing composition of this embodiment may contain at least one selected from the group consisting of organic acids and salts thereof (excluding the component (C) and those having a carboxyl group or a sulfo group in the water-soluble polymer). One kind. Organic acids and their salts can sometimes increase the polishing speed of semiconductor substrates including molybdenum films and silicon oxide films through synergistic effects with component (A).

As the organic acid and its salt, compounds having a carboxyl group and compounds having a sulfo group are preferred. Examples of the compound having a carboxyl group include stearic acid, lauric acid, oleic acid, myristic acid, alkenylsuccinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, and formic acid. , acetic acid, oxalic acid, citric acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinolinic acid, quinalic acid, amide sulfate, propionic acid, trifluoroacetic acid; and their salts . Examples of the compound having a sulfo group include alkylbenzenesulfonic acids such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid; alkylnaphthalenesulfonic acids such as butylnaphthalenesulfonic acid; and α-olefins such as tetradecenesulfonic acid. Sulfonic acid; and their salts. These compounds may be used individually by 1 type, and may be used in combination of 2 or more types.

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

＜Inorganic acids and their salts＞ As the inorganic acid, at least one selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and salts thereof is preferred. Furthermore, the inorganic acid may form a salt with a base separately added to the chemical mechanical polishing composition.

＜Basic compound＞ Examples of basic compounds include organic bases and inorganic bases. The organic base is preferably an amine, and examples thereof include triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, and ethylenediamine. Amine, diglycolamine, isopropylamine, etc. Examples of the inorganic base include ammonia, potassium hydroxide, sodium hydroxide, and the like. Among these alkaline compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used individually by 1 type, or in combination of 2 or more types.

＜Hydrogen peroxide＞ The chemical mechanical polishing composition of this embodiment may contain hydrogen peroxide, but preferably does not contain hydrogen peroxide. Hydrogen peroxide over-oxidizes molybdenum and promotes excessive corrosion (etching) of molybdenum parts, so in many cases it is impossible to obtain a good polished surface.

1.5.pH The pH of the chemical mechanical polishing composition of this embodiment is preferably 1 or more, more preferably 1.5 or more, particularly preferably 2 or more. The pH of the chemical mechanical polishing composition of this embodiment is preferably 6 or less, more preferably 5 or less, and particularly preferably 4 or less. When the pH of the chemical mechanical polishing composition of the present embodiment is within the above range, the surface of the molybdenum film is easily oxidized effectively to form a fragile modified layer, so the polishing rate of the molybdenum film tends to increase.

Furthermore, the pH of the chemical mechanical polishing composition can be adjusted, for example, by adding the component (C), organic acid (salt), inorganic acid (salt), basic compound, etc., and one of these can be used. above.

In the present invention, pH refers to a 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.).

1.6. Preparation method of chemical mechanical polishing composition The chemical mechanical polishing composition of this embodiment can be prepared by dissolving or dispersing each of the above components in a liquid medium such as water. The method of dissolving or dispersing 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 each component are not particularly limited.

In addition, the composition for chemical mechanical polishing can also be prepared as a concentrated type stock solution and diluted with a liquid medium such as water before use.

2. Grinding method A polishing method according to an embodiment of the present invention includes the step of polishing a semiconductor substrate using the chemical mechanical polishing composition. The composition for chemical mechanical polishing can inhibit the corrosion of the molybdenum film, and at the same time can chemically mechanically polish the semiconductor substrate containing the molybdenum film at a stable polishing speed. Therefore, the semiconductor substrate as the object to be processed preferably includes a portion made of at least one selected from the group consisting of molybdenum and molybdenum alloys. Hereinafter, the polishing method of this embodiment will be described in detail with reference to FIGS. 1 to 4 .

2.1. Processed object FIG. 1 shows an example of a target object 100 suitable for the chemical mechanical polishing method of this embodiment.

(1) First, as shown in FIG. 1 , the base 10 is prepared. The base 10 may include, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional devices such as transistors can also be formed on the base 10 . Next, a silicon oxide film 12 as an insulating film is formed on the substrate 10 using a chemical vapor deposition (CVD) method or a thermal oxidation method.

(2) Next, the silicon oxide film 12 is patterned. Using this as a mask, photolithography is applied to the silicon oxide film 12 to form the through hole 14 .

(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. Since the electrical contact between molybdenum and silicon is not very good, a barrier metal film is used to achieve good electrical contact. Examples of the barrier metal film 16 include titanium and/or titanium nitride.

(4) Next, the CVD method is applied to form the molybdenum film 18.

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

2.2. Chemical mechanical grinding method 2.2.1. The first grinding step As shown in FIG. 2 , the first polishing step is a step of polishing the barrier metal film 16 and the molybdenum film 18 using the chemical mechanical polishing composition until the silicon oxide film 12 is exposed. The chemical mechanical polishing composition has excellent polishing effect not only on the molybdenum film but also on the barrier metal film. Therefore, the barrier metal film 16 and the molybdenum film 18 can be polished and removed in the same process step.

2.2.2. Second grinding step As shown in FIG. 3 , the second polishing step is a step of simultaneously polishing the barrier metal film 16 , the molybdenum film 18 and the silicon oxide film 12 using the chemical mechanical polishing composition. The chemical mechanical polishing composition has non-selective polishing properties for the molybdenum film and the silicon oxide film. Therefore, a finished surface with extremely excellent flatness can be obtained through the second polishing step.

Here, the composition for chemical mechanical polishing used in the second polishing treatment step may be suitably changed within the composition range described above. The composition of the chemical mechanical polishing composition used in the first polishing treatment step may include component (B) appropriately changed. concentration to use. By adjusting the concentration of component (B) so that the ratio of the polishing speed of the silicon oxide film to the polishing speed of the molybdenum film is 1 or more, over-polishing of the molybdenum film relative to the silicon oxide film can be sufficiently suppressed, and therefore stable The semiconductor substrate including the molybdenum film and the silicon oxide film is polished at the polishing speed. In addition, by adjusting the other potential or degree of association in component (A) in the chemical mechanical polishing composition, the ratio of the polishing speed of the silicon oxide film to the polishing speed of the molybdenum film can be adjusted to 1 or more.

2.2.3. Chemical mechanical grinding device In the first polishing process step and the second polishing process step, for example, a chemical mechanical polishing device 200 as shown in FIG. 4 may be used. FIG. 4 is a perspective view schematically showing the chemical mechanical polishing apparatus 200. The polishing step is performed by abutting the carrier head 52 holding the semiconductor substrate 50 while supplying the slurry 44 from the slurry supply nozzle 42 and rotating the turntable 48 to which the polishing cloth 46 is attached. . In addition, FIG. 4 also shows the water supply nozzle 54 and the dresser 56.

The grinding load of the carrier head 52 can be selected in the range of 10 hPa ~ 980 hPa, preferably 30 hPa ~ 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 44 supplied from the slurry supply nozzle 42 can be selected in the range of 10 mL/min to 1,000 mL/min, and is preferably 50 mL/min to 400 mL/min.

Examples of commercially available chemical mechanical polishing equipment include: models "EPO-112" and "EPO-222" manufactured by Ebara Manufacturing Co., Ltd.; model "LGP-510" manufactured by Lapmaster SFT Co., Ltd. , "LGP-552"; models "Mirra" and "Reflexion" manufactured by Applied Materials, etc.

3.Examples The present invention will be described below through examples, but the present invention is not limited by these examples. In addition, "parts" and "%" in this example are based on mass unless otherwise specified.

3.1. Preparation of silica particle aqueous dispersion 3.1.1. Preparation of aqueous dispersion A According to Example 3 described in International Publication No. 2008/123373, aqueous dispersion A of pH 7.6 containing 15.5% by mass of silica particles was obtained. The aqueous dispersion A was measured using the dynamic light scattering method (model "Zetasizer Ultra" manufactured by Malvern), and the results were the volume conversion of the silica particles contained in the aqueous dispersion A. The average secondary particle size is 17.3 nm. In addition, a transmission electron microscope (TEM) (model "H-7650" manufactured by Hitachi High-Tech Co., Ltd.) was used to photograph the aqueous dispersion A at a magnification of 30,000 times for observation. 50 images of silica particles were obtained, the distance of the longest straight line connecting the end portions of the particle images was measured, and the average value of the values was calculated as the average primary particle diameter. The average primary particle diameter of the silica particles contained in the water dispersion A calculated in this way was 15.8 nm. Using the average primary particle diameter and the average secondary particle diameter calculated by the above method, the degree of association was calculated by the following calculation formula. As a result, the degree of association of the silica particles contained in the aqueous dispersion A was 1.1. Degree of association = (average secondary particle size) / (average primary particle size) Hereinafter, the average primary particle size, the average secondary particle size, and the degree of association of the silica particles contained in each aqueous dispersion were measured and calculated by the same method.

3.1.2. Preparation of aqueous dispersion B Heat 2520 g of aqueous dispersion A (15.5% colloidal silica dispersion) to 60°C. Then, 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 to obtain a carboxyl group containing an average secondary particle diameter of 17.3 nm. Aqueous dispersion B of surface-modified silica particles.

3.1.3. Preparation of aqueous dispersion C 25% ammonia water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 2520 g of aqueous dispersion A (15.5% colloidal silica dispersion) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical Industry 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 and Wako Pure Chemical Industries, Ltd.) was added and refluxed at normal pressure for 8 hours to obtain silica particles surface-modified with a sulfo group containing an average secondary particle diameter of 17.3 nm. Aqueous dispersion C.

3.1.4. Preparation of aqueous dispersion D PL-1 (manufactured by Fuso Chemical Industry Co., Ltd., 12% colloidal silica dispersion) was directly used as aqueous dispersion D. When measured by the above method, the average secondary particle size of the silica particles contained in the aqueous dispersion D was 30.1 nm.

3.1.5. Preparation of aqueous dispersion E 25% ammonia water (manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd.) was added to 3250 g of PL-1 (manufactured by Fuso Chemical Industry Co., Ltd., 12% colloidal silica dispersion), and the pH was adjusted to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical Industry 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 and Wako Pure Chemical Industries, Ltd.) was added and refluxed at normal pressure for 8 hours to obtain silica particles surface-modified with a sulfo group containing an average secondary particle diameter of 30.1 nm. Aqueous dispersion E.

3.1.6. Preparation of aqueous dispersion F 1950 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion) was heated to 60°C. Then, 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 to obtain a carboxyl group containing an average secondary particle size of 58.2 nm. Aqueous dispersion F of surface-modified silica particles.

3.1.7. Preparation of aqueous dispersion G 25% ammonia water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 2000 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical Industry 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.) was added and refluxed at normal pressure for 8 hours to obtain silica particles surface-modified with a sulfo group containing an average secondary particle diameter of 58.2 nm. Aqueous dispersion G.

3.1.8. Preparation of aqueous dispersion H 25% ammonia water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 1950 g of PL-2L (manufactured by Fuso Chemical Industry Co., Ltd., 20% colloidal silica dispersion), and the pH was adjusted to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical Industry 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.) was added and refluxed at normal pressure for 8 hours to obtain silica particles surface-modified with a sulfo group containing an average secondary particle diameter of 22.5 nm. Aqueous dispersion H.

3.1.9. Preparation of aqueous dispersion I 1950 g of PL-2L (manufactured by Fuso Chemical Industry Co., Ltd., 20% colloidal silica dispersion) was heated to 60°C. Then, 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 to obtain a carboxyl group containing an average secondary particle diameter of 22.5 nm. Aqueous dispersion I of surface-modified silica particles.

3.1.10. Preparation of aqueous dispersion J 25% ammonia water (manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd.) was added to 6510 g of PL-06L (manufactured by Fuso Chemical Industry Co., Ltd., 6% colloidal silica dispersion), and the pH was adjusted to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical Industry 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.) was added and refluxed at normal pressure for 8 hours to obtain silica particles surface-modified with a sulfo group containing an average secondary particle diameter of 7.4 nm. Aqueous dispersion of J.

3.1.11. Preparation of aqueous dispersion K 6510 g of PL-06L (manufactured by Fuso Chemical Industry Co., Ltd., 6% colloidal silica dispersion) was heated to 60°C. Then, 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 to obtain a carboxyl group containing an average secondary particle diameter of 7.4 nm. Aqueous dispersion K of surface-modified silica particles.

3.1.12. Preparation of aqueous dispersion L A mixture of 70 g of methanol and 11.3 g of 3-aminopropyltriethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to 2520 g of aqueous dispersion A (15.5% colloidal silica dispersion). , reflux for 2 hours under normal pressure. Then, pure water was added dropwise while keeping the capacity constant, and the dropwise addition of pure water was terminated when the temperature at the top of the tower reached 100°C. Thus, dioxide surface-modified with amine groups containing an average secondary particle size of 17.3 nm was obtained. Aqueous dispersion of silicon particles L.

3.2. Preparation of ingredient (C) 3.2.1. Preparation of octyl imino dipropionate As alkylamine, 2.5 g (19.5 mmol) of octylamine (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 added to 5.0 mL of water. , ethanol (manufactured by Kanto Chemical Co., Ltd.) into a mixed solution of 32 mL, and stirred under reflux for 6 hours. During the reflux stirring, 7.8 mL of a potassium hydroxide aqueous solution (5.0 mol/L) prepared from potassium hydroxide (manufactured by Kanto Chemical Co., Ltd.) was added to adjust the pH. Then, the solution was cooled to 4°C to form a precipitate. The resulting precipitate was washed with ethanol, filtered, and dried under reduced pressure to recover the solid to obtain octyl imino dipropionate.

3.2.2. Preparation of lauryl imino dipropionate The same operation as described in "3.2.1. Preparation of octyl imino dipropionate" was performed except that 3.6 g (19.5 mmol) of laurylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the alkylamine. , to obtain lauryl imino dipropionate.

3.2.3. Preparation of myristyl imino dipropionate The same operation as described in "3.2.1. Preparation of octyl iminodipropionate" was performed except that 4.2 g (19.5 mmol) of myristamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the alkylamine. , to obtain myristyl imino dipropionate.

3.2.4. Preparation of palmitiminodipropionate The same operation as described in "3.2.1. Preparation of octyl iminodipropionate" was carried out except that 4.7 g (19.5 mmol) of palmitamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the alkylamine. Palmitiminodipropionate was obtained.

3.2.5. Preparation of stearyl imino dipropionate The same operation as described in "3.2.1. Preparation of octyl iminodipropionate" was performed except that 5.3 g (19.5 mmol) of stearylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the alkylamine. , to obtain stearyl imino dipropionate.

3.3. Preparation of compositions for chemical mechanical polishing Each component was mixed so as to obtain the composition shown in Tables 1 to 3, and if necessary, an aqueous potassium hydroxide solution (Kanto Chemical Co., Ltd.) was added as a pH adjuster so as to obtain the pH shown in Tables 1 to 3. Manufactured under the trade name "48% potassium hydroxide aqueous solution"), ammonia (manufactured by Fujifilm Wako Pure Chemical Co., Ltd., trade name "ammonia water"), maleic acid (manufactured by Fujifilm Wako Pure Chemical Co., Ltd., under the trade name " Maleic acid") was adjusted, and pure water was added so that the total amount of all components became 100% by mass, to prepare chemical mechanical polishing compositions for each Example and each Comparative Example. For each chemical mechanical polishing composition obtained in the above manner, the hetapotential of the abrasive grains was measured using a hetapotential measuring device (manufactured by Dispersion Technology Inc., model "DT300"), and the measurement results were They are shown together in Table 1 to Table 3.

3.4. Evaluation methods 3.4.1. Evaluation of polishing speed of molybdenum film and silicon oxide film Using the chemical mechanical polishing composition prepared in the above, a 12-inch diameter wafer with a molybdenum film of 200 nm and a 12-inch diameter wafer with a silicon oxide film (p-TEOS film) of 1000 nm were prepared. The object to be processed was subjected to a chemical mechanical polishing test under the following conditions, and then scrubbing was performed under the following conditions. (Grinding conditions) ・Grinding device: Manufactured by Applied Materials, model number "Reflexion-LK" ・Polishing pad: "Porous polyurethane pad; H800-type (type) 1 (3-1S) 775" manufactured by Fujibo Co., Ltd. ・Chemical mechanical polishing composition supply rate: 300 mL/min ・Plate rotation speed: 100 rpm ・Grinding head speed: 90 rpm ・Grinding head pressing pressure: 2 psi ・Grinding time: 60 seconds ・Polishing speed (nm/minute) = (film thickness before polishing - film thickness after polishing) / polishing time (brush cleaning conditions) ・Treatment agent: pure water ・Upper brush speed: 400 rpm ・Lower brush speed: 400 rpm ・Substrate rotation speed: 50 rpm ・Treatment agent supply rate: 1200 mL/min

Furthermore, the thickness of the molybdenum film was measured using a resistivity measuring machine (manufactured by KLA-Tencor, model "RS-100") using the DC 4-probe method, and based on this sheet resistance value and the volume resistivity of molybdenum were calculated from the following formula.・Thickness of the molybdenum film (nm) = [Volume resistivity of the molybdenum film (Ω･m) ÷ Sheet resistance value (Ω/sq)] × 10 ⁹ In addition, the thickness of the silicon oxide film is determined by an optical film thickness measuring device ( Manufactured by KLA-Tencor, model "ASET F5x") to measure.

The evaluation criteria for the polishing rate of the molybdenum film are as follows. The evaluation results of the polishing rate of the molybdenum film are collectively shown in Tables 1 to 3. (Evaluation criteria) ・AA: When the polishing speed is 2.5 nm/min or more and less than 30 nm/min, it is an appropriate polishing speed and is therefore judged to be very good. ・A: When the polishing speed is 30 nm/min or more and less than 40 nm/min, the polishing speed is high and requires careful control during mass production, but it is judged to be good because it is practical. ・B: When the polishing speed is less than 2.5 nm/min, the polishing speed is too low to be practical, so it is judged as defective. Alternatively, when the polishing speed is 40 nm/min or more, the polishing speed is too high to be controllable during mass production and is difficult to put into practical use, so it is judged as defective.

In addition, using the polishing rate of the molybdenum film and the polishing rate of the silicon oxide film calculated above, the polishing rate ratio was calculated according to the following formula. Polishing speed ratio = polishing speed of silicon oxide film (nm/min) / polishing speed of molybdenum film (nm/min) (Evaluation criteria) ・AA: When the polishing speed ratio is 1 or more, overpolishing of the molybdenum film relative to the silicon oxide film can be sufficiently suppressed, so it is judged to be very good. ・A: When the polishing speed ratio is 0.5 or more and less than 1, the polishing speed of the molybdenum film is larger than that of the silicon oxide film, which requires careful control during mass production. However, it is practical and is therefore judged to be good. ・B: When the polishing speed ratio is less than 0.5, the molybdenum film is polished excessively relative to the silicon oxide film, making it difficult to put it into practical use, so it is judged as defective.

3.4.2. Etching speed evaluation of molybdenum film The chemical mechanical polishing composition prepared in the above was heated to 60°C, and a wafer with a molybdenum film of 200 nm cut into 30 mm × 10 mm was immersed for 5 minutes. Then, the wafer was taken out, washed with running water, and the thickness of the molybdenum film was measured by the same method as described in "3.4.1. Evaluation of polishing speed of molybdenum film and silicon oxide film". Then, based on the change in thickness of the molybdenum film before and after immersion, the etching rate was calculated using the following equation. ・Etching rate of molybdenum film (nm/minute) = (thickness of molybdenum film before etching (nm) - thickness of molybdenum film after etching (nm)) / etching time (minutes)

The evaluation criteria for the etching rate of the molybdenum film are as follows. The evaluation results of the etching rate of the molybdenum film are collectively shown in Tables 1 to 3. (Evaluation criteria) ・A: When the etching rate is less than 0.1 nm/minute, it is judged as good. ・B: When the etching rate is 0.1 nm/min or more, the etching rate is too high to be practical, so it is judged as defective.

3.4.3. Defect evaluation of silicon oxide film Use a defect inspection device (manufactured by KLA-Tencor, model "Surfscan SP2") to measure the polishing speed obtained in "3.4.1. Evaluation of polishing speed of molybdenum film and silicon oxide film" The number of defects on the entire surface of the resulting wafer with silicon oxide film was measured.

The evaluation criteria for the number of defects are as follows. The evaluation results of the number of defects in the silicon oxide film are collectively shown in Tables 1 to 3. (Evaluation criteria) ・A: When the number of defects in the silicon oxide film is less than 100, it is suitable for practical use and is therefore judged to be good. ・B: When the number of defects in the silicon oxide film is 100 or more, it cannot be used for practical purposes and is therefore judged as defective.

3.5. Evaluation results Tables 1 to 3 show the composition of the chemical mechanical polishing composition used in each Example and each Comparative Example and each evaluation result.

[Table 1] Example 1 2 3 4 5 6 7 8 9 10 11 12 Compositions for chemical mechanical polishing Ingredients (A) Kind Aqueous dispersion B Aqueous dispersion B Aqueous dispersion F Aqueous dispersion I Aqueous dispersion K Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Average primary particle size (nm) 15.8 15.8 46.3 22.1 7 15.8 15.8 15.8 15.8 15.8 15.8 15.8 Average secondary particle size (nm) 17.3 17.3 58.2 22.5 7.4 17.3 17.3 17.3 17.3 17.3 17.3 17.3 degree of association 1.1 1.1 1.3 1.0 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 Zeta potential (mV) -6 -6 -6 -6 -6 -10 -14 -6 -6 -19 -35 -6 Content (mass%) 4 2 6 3 5 4 4 4 4 4 4 2 Ingredients (B) Kind Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Content (mass%) 0.03 0.2 0.03 0.07 0.07 0.02 0.02 0.05 0.3 0.2 0.1 0.01 Fe(III) content (ppm) 42 281 42 98 98 28 28 70 421 281 140 14 Ingredients (C) Kind Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Lauryl imino dipropionate Lauryl imino dipropionate Laurylamide propylhydroxysulfobetaine Laurylhydroxysulfobetaine Laurylaminoethylaminoethylglycine Laurylaminoethylaminoethylglycine Laurylaminoethylaminoethylglycine Content (mass%) 0.01 0.01 0.01 0.01 0.01 0.025 0.025 0.01 0.005 0.01 0.01 0.001 Other additives pH adjuster Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid / potassium hydroxide Maleic acid / potassium hydroxide Maleic acid Kind mass % Kind mass % pH 2.1 2.1 2.1 2.1 2.1 3.0 3.5 2.1 2.1 4.0 5.0 2.1 Evaluation results Molybdenum film polishing speed evaluation AA AA A AA AA AA AA AA AA AA AA AA Molybdenum film etching evaluation A A A A A A A A A A A A Grinding speed ratio evaluation AA AA AA AA AA AA AA AA AA AA A AA Silicon Oxide Film Defect Evaluation A A A A A A A A A A A A

[Table 2] Example 13 14 15 16 17 18 19 20 twenty one twenty two twenty three twenty four Compositions for chemical mechanical polishing Ingredient(A) Kind Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion C Aqueous dispersion E Aqueous dispersion C Aqueous dispersion G Aqueous dispersion H Aqueous dispersionJ Average primary particle size (nm) 15.8 15.8 15.8 15.8 15.8 15.8 15.8 20.0 15.8 46.3 22.1 7.0 Average secondary particle size (nm) 17.3 17.3 17.3 17.3 17.3 17.3 17.3 30.1 17.3 58.2 22.5 7.4 degree of association 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.5 1.1 1.3 1.0 1.1 Zeta potential (mV) -6 -6 -6 -6 -6 -6 -twenty three -30 -twenty three -30 -twenty three -12 Content (mass%) 2 4 4 4 4 4 4 4 2 6 3 5 Ingredient(B) Kind Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron citrate trihydrate Iron acetyl acetonate Diethylenetriaminepentaacetate iron diammonium salt 1,3-Diaminopropane ferric ammonium tetraacetate monohydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate Content (mass%) 0.005 0.005 0.3 0.177 0.12 0.005 0.03 0.03 0.5 0.1 0.15 0.07 Fe(III) content (ppm) 7 7 561 281 140 7 42 42 701 140 210 98 Ingredients (C) Kind Stearyliminodipropionate - Myristyl imino dipropionate Palmityl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Laurylaminoethylaminoethylglycine Octyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Content (mass%) 0.005 - 0.01 0.05 0.01 0.01 0.01 0.01 0.01 0.1 0.01 0.01 Other additives pH adjuster Maleic acid Maleic acid Maleic acid / ammonia Maleic acid / ammonia Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Kind Ethylenediaminetetraacetic acid diammonium salt Ethylenediaminetetraacetic acid diammonium salt Content (mass%) 0.16 0.16 Kind Content (mass%) pH 1.5 2.1 2.1 1.5 2.1 2.1 2.1 2.1 1.5 2.1 2.1 2.1 Evaluation results Molybdenum film polishing speed evaluation AA A AA AA AA AA AA A A A AA AA Molybdenum film etching evaluation A A A A A A A A A A A A Grinding speed ratio evaluation AA AA AA AA AA AA A AA A AA A AA Silicon Oxide Film Defect Evaluation A A A A A A A A A A A A

[table 3] Comparative example 1 2 3 4 5 6 7 Compositions for chemical mechanical polishing Ingredient(A) Kind Aqueous dispersion A Aqueous dispersion A Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion B Aqueous dispersion L Average primary particle size (nm) 15.8 15.8 15.8 15.8 15.8 15.8 15.8 Average secondary particle size (nm) 17.3 17.3 17.3 17.3 17.3 17.3 17.3 degree of association 1.1 1.1 1.1 1.1 1.1 1.1 1.1 Zeta potential (mV) -6 -6 -35 -35 -35 -35 28 Content (mass%) 2 4 4 4 4 4 4 Ingredient(B) Kind Iron ammonium ethylenediaminetetraacetate dihydrate Iron ammonium ethylenediaminetetraacetate dihydrate - - - - Iron ammonium ethylenediaminetetraacetate dihydrate Content (mass%) 0.2 0.2 - - - - 0.2 Fe(III) content (ppm) 281 281 - - - - 281 Ingredients (C) Kind Cetyl imino dipropionate - Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Myristyl imino dipropionate Content (mass%) 0.01 - 0.01 0.01 0.01 0.01 0.01 Other additives pH adjuster Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Maleic acid Kind hydrogen peroxide Or-periodic acid Ammonium peroxodisulfate Iron(II) sulfate heptahydrate Content (mass%) 0.2 0.2 0.2 0.14 Kind Ethylenediaminetetraacetic acid diammonium salt Content (mass%) 0.16 pH 2.1 2.1 2.1 2.1 2.1 2.1 2.1 Evaluation results Molybdenum film polishing speed evaluation AA AA B B B B AA Molybdenum film etching evaluation A A B B A A A Grinding speed ratio evaluation AA AA B B AA AA AA Silicon Oxide Film Defect Evaluation B B A A A A B

The following products or reagents were used for each component in Table 1 to Table 3 above. ＜Ingredients (A)＞ ・Aqueous dispersion A to water dispersion L: Water dispersion A to water dispersion L prepared in the section "3.1. Preparation of silica particle aqueous dispersion" ＜Ingredients (B)＞ ・Fe ammonium ethylenediaminetetraacetate dihydrate: manufactured by Chelest Co., Ltd., trade name "Chelest FN" ・Iron citrate trihydrate: manufactured by Fuso Chemical Industry Co., Ltd., trade name "Fuji Iron Citrate" ・Iron Acetyl Acetonate: Manufactured by Kishida Chemical Co., Ltd., trade name "Iron Acetyl Acetonate (III)" ・Fe diammonium diethylene triamine pentaacetate: manufactured by Chelest Co., Ltd., trade name "Chelest FNZ-50" ・1,3-Diaminopropanetetraacetate ferric ammonium monohydrate: manufactured by Chelest Co., Ltd., trade name "Chelest PD-FN" ＜Component (C)＞ ・Octyl imino dipropionate: The octyl imino dipropionate prepared in the "3.2. Preparation of Component (C)" section ・Lauryl imino dipropionate: The lauryl imino dipropionate prepared in the item "3.2. Preparation of ingredient (C)" ・Myristyl imino dipropionate: Myristyl imino dipropionate prepared in the item "3.2. Preparation of ingredient (C)" ・Palmityl imino dipropionate: Palmityl imino dipropionate prepared in the item "3.2. Preparation of Component (C)" ・Stearyliminodipropionate: Stearyliminodipropionate prepared in the "3.2. Preparation of Component (C)" section ・Lauroylaminoethylaminoethylglycine: Manufactured by Sanyo Chemical Industry Co., Ltd., trade name "REBON S" ・Lauramide propyl hydroxysulfobetaine: Sichuanyan Fine Chemical Co., Ltd., trade name "SOFTAZOLINE (LSB-R)" ・Lauryl hydroxysulfobetaine: manufactured by Kao Co., Ltd., trade name "AMPHITOL 20HD" ＜Other additives＞ ・Hydrogen peroxide: Manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd., trade name "Hydrogen peroxide" ・Ortho-periodic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Ortho-periodic acid" ・Ammonium peroxodisulfate: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Ammonium peroxodisulfate" ・Iron (II) sulfate heptahydrate: Manufactured by Fujifilm and Wako Pure Chemical Industries, Ltd., trade name "Iron (II) sulfate heptahydrate" ・Ethylenediaminetetraacetic acid diammonium salt: manufactured by Chelest Co., Ltd., trade name "Chelest 2N-40"

According to the chemical mechanical polishing compositions of Examples 1 to 24 in which the component (A) and the component (B) having a specific functional group were used in combination, it was found that the molybdenum film can be oxidized to accelerate polishing and can prevent molybdenum from interacting with anions. kind of excessive reaction, thereby reducing the occurrence of corrosion of the molybdenum film. In addition, it was found that 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 aggregation of the abrasive grains is suppressed, thereby reducing the occurrence of defects in the silicon oxide film. At the same time, both the molybdenum film and the silicon oxide film are polished at a stable polishing speed.

On the other hand, it was found that the chemical mechanical polishing compositions of Comparative Examples 1 to 2 and 7 containing abrasive grains without a specific functional group easily generate defects in the silicon oxide film and are difficult to put into practical use. In addition, according to the chemical mechanical polishing compositions of Comparative Examples 3 to 6 that do not contain component (B), it was found that the polishing rate of the molybdenum film was too low and therefore it was difficult to put them into practical use.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes structures that are substantially the same as those described in the embodiments (for example, structures with the same functions, methods, and results, or structures with the same purposes and effects). In addition, the present invention includes structures in which non-essential parts of the structures described in the embodiments are replaced. In addition, the present invention includes a structure that exhibits the same operation and effect as the structure described in the embodiment or a structure that can achieve the same purpose. In addition, the present invention includes structures obtained by adding publicly known techniques to the structures described in the embodiments.

10:Matrix 12:Silicon oxide film 14:Through hole 16: Barrier metal film 18:Molybdenum film 42: Slurry supply nozzle 44:Slurry 46:Abrasive cloth 48:Turntable 50:Semiconductor substrate 52: Carrier head 54:Water supply nozzle 56: Dresser 100: Processed object 200:Chemical mechanical grinding device

FIG. 1 is a cross-sectional view schematically showing an object to be processed suitable for use in the polishing step of 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 device.

Claims (8)

A composition for chemical mechanical polishing, containing: abrasive grains (A), and iron (III) compounds (B), the abrasive grains (A) having a functional group represented by the following general formula (1) and the following general formula: At least one functional group among the functional groups represented by formula (2), -SO ₃ ^- M ⁺・・・・・(1) -COO ^- M ⁺・・・・・(2) The formula (1) and In the formula (2), M ⁺ represents a monovalent cation. The chemical mechanical polishing composition according to claim 1, further comprising compound (C) having at least one functional group selected from the group consisting of amine groups and salts thereof, and At least one functional group from the group consisting of carboxyl group, sulfo group, and salts thereof. The chemical mechanical polishing composition according to claim 1 or claim 2, wherein the abrasive grains (A) in the chemical mechanical polishing composition have an average secondary particle diameter of 5 nm or more and 100 nm or less. The chemical mechanical polishing composition according to claim 1 or claim 2, wherein the degree of association of the abrasive grains (A) in the chemical mechanical polishing composition is 1.0 or more and 2.0 or less. The composition for chemical mechanical polishing as described in claim 1 or claim 2, wherein the other potential of the abrasive grains (A) in the composition for chemical mechanical polishing is less than 0 mV. The composition for chemical mechanical polishing according to Claim 1 or Claim 2, wherein the pH is 1 or more and 6 or less. A polishing method, including 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 includes a portion composed of at least one selected from the group consisting of molybdenum and molybdenum alloys.