Chemical mechanical polishing composition and polishing method

Abstract

To provide a chemical mechanical polishing composition capable of chemically mechanically polishing a semiconductor substrate containing ruthenium while maintaining a stable polishing rate while suppressing corrosion of ruthenium.SOLUTION: A chemical mechanical polishing composition according to the present invention includes abrasive grains (A), and an acid or its salt (B) containing at least one anion selected from the group consisting of periodate (IO4-), hypochlorite (ClO-), chlorite (ClO2-), and hypobromite (BrO-), and the abrasive grain (A) has at least one functional group among the functional groups represented by the following general formulas (1) to (4). -SO3-M+ (1). -COO-M+ (2). -NR1R2 (3). -N+R1R2R3M- (4).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a chemical mechanical polishing composition and a polishing method using the same. [Background technology]

[0002] With the improvement of manufacturing technology for semiconductor integrated circuits, there is a demand for higher integration and faster operation of semiconductor elements. Accordingly, the flatness of the semiconductor substrate surface required in the manufacturing process of fine circuits in semiconductor elements is becoming more stringent, and chemical mechanical polishing (CMP) has become an essential technology in the manufacturing process of semiconductor elements.

[0003] CMP is a technique for chemically and mechanically polishing a semiconductor substrate by supplying a chemical mechanical polishing composition onto a polishing pad attached to a platen, pressing the semiconductor substrate against the polishing pad, and sliding the semiconductor substrate and the polishing pad against each other. In CMP, the unevenness of the semiconductor substrate surface can be removed and the surface can be flattened by chemical reactions with reagents and mechanical polishing with abrasive grains.

[0004] In recent years, methods using ruthenium films have been investigated to improve the embedding of copper into recesses when forming copper wiring on semiconductor substrates manufactured through such CMP (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2009-514219 [Patent Document 2] Special Publication No. 2010-535424 [Patent Document 3] International Publication No. 2019 / 151145 Summary of the Invention [Problem to be solved by the invention]

[0006] In such CMP, in order to suppress the generation of highly volatile ruthenium tetroxide gas and polish the part containing ruthenium, it is necessary to perform chemical mechanical polishing using a basic chemical mechanical polishing composition and 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, although the generation of ruthenium tetroxide gas can be suppressed, the insufficiently oxidized ruthenium oxide adheres to the polishing pad surface, deteriorating the polishing characteristics of the polishing pad. As a result, it is difficult to perform chemical mechanical polishing of a semiconductor substrate containing ruthenium while maintaining a stable polishing rate. On the other hand, when a halogen-based oxidizing agent having high oxidizing power is used, there is a risk of corroding ruthenium.

[0007] Some aspects of the present invention provide a chemical mechanical polishing composition that can perform chemical mechanical polishing of a semiconductor substrate containing ruthenium while suppressing corrosion of ruthenium and maintaining a stable polishing rate. [Means for solving the problem]

[0008] The present invention has been made to solve at least some of the above problems, and can be realized in any of the following aspects.

[0009] One aspect of the chemical mechanical polishing composition of the present invention is Abrasive grains (A); Periodate ion (IO4 - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 - ) and hypobromite ion (BrO - (B) an acid or a salt thereof containing at least one anion selected from the group consisting of The abrasive grains (A) have at least one functional group selected from the functional groups represented by the following general formulas (1) to (4). -SO3 - M +...(1) -COO - M + ...(2) (In the above formulas (1) and (2), M + represents a monovalent cation.) -NR 1 R 2 ...(3) -N + R 1 R 2 R 3 M - ...(4) (In the above formulas (3) and (4), R 1 , R 2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0010] In one embodiment of the chemical mechanical polishing composition, The abrasive grains (A) in the chemical mechanical polishing composition may have an absolute value of zeta potential of 10 mV or more.

[0011] In any one of the embodiments of the chemical mechanical polishing composition, Furthermore, it may contain a compound (D) having at least one functional group selected from the group consisting of an amino group and a salt thereof, and at least one functional group selected from the group consisting of a carboxy group and a salt thereof.

[0012] In any one of the embodiments of the chemical mechanical polishing composition, The pH may be 6 or more and 12 or less.

[0013] One aspect of the polishing method according to the present invention is to The method includes polishing a semiconductor substrate with the chemical mechanical polishing composition of any one of the above embodiments.

[0014] In one embodiment of the polishing method, The semiconductor substrate may include a portion made of at least one selected from the group consisting of ruthenium and a ruthenium alloy. Effect of the Invention

[0015] According to the chemical mechanical polishing composition of the present invention, it is possible to perform chemical mechanical polishing of a semiconductor substrate containing ruthenium while maintaining a stable polishing rate, while suppressing corrosion of ruthenium. [Brief description of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing a schematic diagram of a target object suitable for use in a polishing process according to an embodiment of the present invention. [Diagram 2] 4 is a cross-sectional view showing a schematic diagram of a target object at the end of a first polishing process. FIG. [Diagram 3] 4 is a cross-sectional view showing a schematic diagram of the object to be polished at the end of a second polishing process. FIG. [Figure 4] FIG. 1 is a perspective view showing a schematic diagram of a chemical mechanical polishing apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Preferred embodiments of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and includes various modified examples that are implemented within the scope of the present invention.

[0018] In this specification, a numerical range described as "A to B" is interpreted as including numerical value A as the lower limit and numerical value B as the upper limit.

[0019] 1. Chemical mechanical polishing composition The chemical mechanical polishing composition according to one embodiment of the present invention comprises abrasive grains (A) (also referred to as “component (A)” in this specification) and periodate ions (IO - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 -) and hypobromite ion (BrO - and (B) an acid or a salt thereof (B) (also referred to as "component (B)" in this specification) containing at least one anion selected from the group consisting of, wherein the abrasive grain (A) has at least one functional group selected from the functional groups represented by the following general formulas (1) to (4). -SO3 - M + ...(1) -COO - M + ...(2) (In the above formulas (1) and (2), M + represents a monovalent cation.) -NR 1 R 2 ...(3) -N + R 1 R 2 R 3 M - ...(4) (In the above formulas (3) and (4), R 1 , R 2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.) Hereinafter, each component contained in the chemical mechanical polishing composition according to this embodiment will be described in detail.

[0020] 1.1. Component (A) The chemical mechanical polishing composition according to the present embodiment contains abrasive grains (A). Component (A) includes inorganic particles such as silica, ceria, alumina, zirconia, and titania, among which silica particles are preferred. Examples of silica particles include fumed silica and colloidal silica, among which colloidal silica is preferred. Colloidal silica is preferably used from the viewpoint of reducing polishing defects such as scratches. As the colloidal silica, for example, one produced by the method described in JP-A-2003-109921 can be used.

[0021] When component (A) is a silica particle mainly composed of silica, it may further contain other components. Examples of other components include aluminum compounds, silicon compounds, etc. By further containing an aluminum compound or a silicon compound in the silica particle, the surface hardness of the silica particle can be reduced, so that the occurrence of polishing scratches and dishing on the polished surface can be further reduced while maintaining a stable polishing rate.

[0022] Examples of aluminum compounds include aluminum hydroxide, aluminum oxide (alumina), aluminum chloride, aluminum nitride, aluminum acetate, aluminum phosphate, aluminum sulfate, sodium aluminate, potassium aluminate, etc. On the other hand, examples of silicon compounds include silicon nitride, silicon carbide, silicates, silicone, silicone resins, etc.

[0023] The shape of component (A) is not particularly limited, and may be spherical, cocoon-shaped, chain-shaped, or have multiple protrusions on the surface. Abrasive grains having multiple protrusions on the surface can be produced by applying the methods described in, for example, JP 2007-153732 A or JP 2013-121631 A.

[0024] 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 component (A) is within the above range, the electrostatic repulsive force between the abrasive grains effectively prevents aggregation of the grains, and the semiconductor substrate containing ruthenium can be more stably polished. The polishing can be performed at a polishing rate of 1000 rpm. Examples of the zeta potential measuring device include "ELSZ-2000ZS" manufactured by Otsuka Electronics Co., Ltd., "Zetasizer Ultra" manufactured by Malvern, and "DT300" manufactured by Dispersion Technology Inc.

[0025] At least a portion of the surface of component (A) has at least one type of functional group selected from the functional groups represented by the following general formulas (1) to (4) (hereinafter also referred to as "specific functional group"). -SO3 - M + ...(1) -COO - M + ...(2) (In the above formulas (1) and (2), M + represents a monovalent cation.) -NR 1 R 2 ...(3) -N + R 1 R 2 R 3 M - ...(4) (In the above formulas (3) and (4), R 1 , R 2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.) The abrasive grains, at least a part of whose surface is modified with a specific functional group, tend to have a larger absolute value of the zeta potential than the abrasive grains that are not surface-modified with a specific functional group, and the electrostatic repulsion between the abrasive grains is increased. As a result, the dispersibility of the abrasive grains in the chemical mechanical polishing composition is improved, and high-speed polishing can be achieved while reducing the occurrence of polishing scratches and dishing.

[0026] The component (A) may have a functional group represented by the following general formula (1). -SO3 - M + ...(1) (M + represents a monovalent cation.)

[0027] In the above general formula (1), M + Examples of monovalent cations represented by the formula (I) include, but are not limited to, H + , Li + , Na + , K+ , NH4 + In other words, the functional group represented by the above general formula (1) can be rephrased as "at least one functional group selected from the group consisting of sulfo groups and salts thereof." Here, the "salt of a sulfo group" refers to a functional group that converts the hydrogen ion contained in the sulfo group (-SO3H) into Li + , Na + , K + , NH4 + The term "component (A)" refers to a functional group substituted with a monovalent cation such as . Component (A) having a functional group represented by the above general formula (1) is an abrasive grain having a functional group represented by the above general formula (1) fixed to its surface via a covalent bond, and does not include abrasive grains having a compound having a functional group represented by the above general formula (1) physically or ionically adsorbed to their surface.

[0028] The component (A) having a 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 thoroughly stirred in an acidic medium to covalently bond the mercapto group-containing silane coupling agent to the surface of the silica. Here, examples of the mercapto group-containing silane coupling agent include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Next, an appropriate amount of hydrogen peroxide is further added and the mixture is left to stand for a sufficient period to obtain the component (A) having a functional group represented by the above general formula (1).

[0029] The zeta potential of component (A) having a functional group represented by the above general formula (1) is a negative potential in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less, more preferably -15 mV or less, and particularly preferably -20 mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion between the abrasive grains effectively prevents the particles from agglomerating with each other, and the semiconductor substrate containing ruthenium may be polished at a more stable polishing rate. The zeta potential measuring device can be the above-mentioned device. The zeta potential of component (A) can be adjusted by appropriately increasing or decreasing the amount of the above-mentioned mercapto group-containing silane coupling agent or the like added.

[0030] When the chemical mechanical polishing composition according to this embodiment contains component (A) having a functional group represented by the above general formula (1), the content of component (A) is preferably 0.5% by mass or more, more preferably 1% by mass or more, when the total mass of the chemical mechanical polishing composition is taken as 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 taken as 100% by mass. When the content of component (A) having a functional group represented by the above general formula (1) is within the above range, a semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may be improved.

[0031] Component (A) may have a functional group represented by the following general formula (2). -COO - M + ...(2) (M + represents a monovalent cation.)

[0032] In the above general formula (2), M + Examples of monovalent cations represented by the formula (I) include, but are not limited to, H + , Li + , Na + , K + , NH4 +In other words, the functional group represented by the above general formula (2) can be rephrased as "at least one functional group selected from the group consisting of a carboxy group and its salts." Here, the "salt of a carboxy group" refers to a functional group that converts a hydrogen ion contained in a carboxy group (-COOH) into a Li + , Na + , K + , NH4 + The component (A) having the functional group represented by the above general formula (2) is an abrasive grain having the functional group represented by the above general formula (2) fixed to its surface via a covalent bond, and does not include abrasive grains having a compound having the functional group represented by the above general formula (2) physically or ionically adsorbed to their surface.

[0033] The component (A) having the functional group represented by the above general formula (2) can be produced as follows. First, silica prepared by a known method and a silane coupling agent containing a carboxylic acid anhydride are thoroughly stirred in a basic medium, and the silane coupling agent containing a carboxylic acid anhydride is covalently bonded to the surface of the abrasive grain, thereby obtaining an abrasive grain having the functional group represented by the above general formula (2). Here, the silane coupling agent containing a carboxylic acid anhydride can be, for example, 3-(triethoxysilyl)propylsuccinic anhydride.

[0034] The zeta potential of component (A) having a functional group represented by the above general formula (2) is a negative potential in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less, more preferably -15 mV or less, and particularly preferably -20 mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion between the abrasive grains effectively prevents the particles from agglomerating with each other, and the semiconductor substrate containing ruthenium may be polished at a more stable polishing rate. The zeta potential measuring device can be the above-mentioned device. The zeta potential of component (A) having a functional group represented by the above general formula (2) can be adjusted by appropriately increasing or decreasing the amount of the above-mentioned carboxylic anhydride-containing silane coupling agent or the like added.

[0035] When the chemical mechanical polishing composition according to this embodiment contains the component (A) represented by the general formula (2), the content of the component (A) 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, when the total mass of the chemical mechanical polishing composition is taken as 100% by mass. The content of the component (A) is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 5% by mass or less, when the total mass of the chemical mechanical polishing composition is taken as 100% by mass. When the content of the component (A) is within the above range, a semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may be good.

[0036] Component (A) may 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 the above formula (3) and the above formula (4), R 1 , R 2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0037] The functional group represented by the general formula (3) represents an amino group, and the functional group represented by the general formula (4) represents a salt of an amino group. Therefore, the functional group represented by the general formula (3) and the functional group represented by the general formula (4) can be collectively referred to as "at least one functional group selected from the group consisting of amino groups and their salts". The component (A) having the functional group represented by the general formula (3) and / or the general formula (4) is an abrasive grain having the functional group represented by the general formula (3) and / or the general formula (4) fixed to its surface via a covalent bond, and does not include an abrasive grain having a compound having the functional group represented by the general formula (3) and / or the general formula (4) physically or ionically adsorbed to its surface.

[0038] In the above general formula (4), M - Examples of anions represented by the formula (I) include, but are not limited to, OH - , F - , Cl - , Br - , I - , C.N. - In addition to the above anions, anions derived from acidic compounds can also be mentioned.

[0039] In the above general formula (3) and the above general formula (4), R 1 ~R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, R 1 ~R 3 Two or more of these may be bonded to form a ring structure.

[0040] R 1 ~R 3 The hydrocarbon group represented by the formula (I) may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, and an alicyclic hydrocarbon group. The aliphatic groups in the aliphatic hydrocarbon group and the araliphatic 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, and aryl groups.

[0041] The alkyl group is preferably a lower alkyl group having 1 to 6 carbon atoms, and more preferably a lower alkyl group having 1 to 4 carbon atoms. Examples of such alkyl groups include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a cyclopentyl group, and a cyclohexyl group.

[0042] The alkenyl group is usually preferably a lower alkenyl group having 1 to 6 carbon atoms, and more preferably a lower alkenyl group having 1 to 4 carbon atoms. Examples of such alkenyl groups include a vinyl group, an n-propenyl group, an iso-propenyl group, an n-butenyl group, an iso-butenyl group, a sec-butenyl group, and a tert-butenyl group.

[0043] The aralkyl group is usually preferably one having a carbon number of 7 to 12. Examples of such aralkyl groups include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a phenylhexyl group, a methylbenzyl group, a methylphenethyl group, and an ethylbenzyl group.

[0044] The aryl group is preferably one having 6 to 14 carbon atoms. Examples of such an alkyl group include a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,5-xylyl group, a naphthyl group, and an anthryl group.

[0045] The aromatic rings of the above aryl and aralkyl groups may have, as substituents, for example, lower alkyl groups such as methyl and ethyl groups, halogen atoms, nitro groups, amino groups, hydroxy groups, and the like.

[0046] The component (A) having the functional group represented by the general formula (3) and / or the general formula (4) can be produced by, for example, thoroughly stirring silica and an amino group-containing silane coupling agent in an acidic medium to covalently bond the amino group-containing silane coupling agent to the surface of the silica, thereby producing abrasive grains having the functional group represented by the general formula (3) and / or the general formula (4). Examples of the amino group-containing silane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, etc.

[0047] The zeta potential of component (A) having functional groups represented by the general formula (3) and / or the general formula (4) is negative in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less, more preferably -15 mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion between the abrasive grains effectively prevents the particles from agglomerating, and the semiconductor substrate containing ruthenium may be polished at a more stable polishing rate. The zeta potential measuring device can be the above-mentioned device. The zeta potential of component (A) having functional groups 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.

[0048] When the chemical mechanical polishing composition according to the present embodiment contains component (A) having a functional group represented by the general formula (3) and / or the general formula (4), the content of component (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more, when the total mass of the chemical mechanical polishing composition is taken as 100% by mass. The content of component (A) is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 5% by mass or less, when the total mass of the chemical mechanical polishing composition is taken as 100% by mass. When the content of component (A) is within the above range, a semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may be good.

[0049] 1.2.Component (B) The chemical mechanical polishing composition according to this embodiment contains periodate ions (IO4 - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 - ) and hypobromite ion (BrO - The anion contained in component (B) is presumed to function as an oxidizing agent, oxidizing ruthenium and promoting polishing.

[0050] Specific examples of component (B) include periodic acid, chlorous acid, hypochlorous acid, hypobromous acid, sodium periodate, potassium periodate, ammonium periodate, sodium chlorite, potassium chlorite, sodium hypochlorite, potassium hypochlorite, sodium hypobromite, etc. 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.

[0051] 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 0.003 mol / L or more, per 1 L of the chemical mechanical polishing composition. 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 0.035 mol / L or less, per 1 L of the chemical mechanical polishing composition. When the content of component (B) is within the above range, ruthenium is oxidized to promote polishing, and excessive reaction between ruthenium and specific anion species is prevented, which may suppress corrosion of ruthenium.

[0052] The content (mass%) of component (B) is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, and particularly preferably 0.1 mass% or more, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. The content (mass%) of component (B) is preferably 10 mass% or less, more preferably 8 mass% or less, and particularly preferably 7 mass% or less, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. When the content of component (B) is within the above range, ruthenium is oxidized to promote polishing, and excessive reaction between ruthenium and specific anion species is prevented, and corrosion of ruthenium may be suppressed.

[0053] 1.3.Component (C) The chemical mechanical polishing composition according to this embodiment may contain hydrogen peroxide (C) (also referred to as "component (C)" in this specification). Hydrogen peroxide (C) oxidizes ruthenium to promote polishing, and also prevents excessive reaction between ruthenium and the specific anion species contained in component (B) by reacting with ruthenium, thereby suppressing the generation of halogen gas and corrosion of ruthenium.

[0054] 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 0.0012 mol / L or more, per 1 L of the chemical mechanical polishing composition. 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 0.3 mol / L or less, per 1 L of the chemical mechanical polishing composition. When the content of component (C) is within the above range, ruthenium is oxidized to promote polishing, and component (C) reacts with ruthenium to prevent excessive reaction between ruthenium and the specific anion species contained in component (B), which may suppress corrosion of ruthenium.

[0055] The content (mass%) of component (C) is preferably 0.0017% by mass or more, more preferably 0.003% by mass or more, and particularly preferably 0.004% by mass or more, when the total mass of the chemical mechanical polishing composition is 100% by mass. The content (mass%) of component (C) is preferably 1.7% by mass or less, more preferably 1.4% by mass or less, and particularly preferably 1% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass. When the content of component (C) is within the above range, ruthenium is oxidized to promote polishing, and component (C) reacts with ruthenium to prevent excessive reaction between ruthenium and the specific anion species contained in component (B), which may suppress corrosion of ruthenium.

[0056] 1.4.Component (D) The chemical mechanical polishing composition of this embodiment may contain a compound (D) (also referred to in this specification as "component (D)") 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.

[0057] The amino group and its salt include functional groups represented by the following general formula (5) or (6). -NR 4 R 5 R 6 R 7 ...(5) -N + R 4 R 5 R 6 M - ...(6) (In the above formula (5) and the above formula (6), R 4 , R 5 , R 6 and R 7 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0058] In the above general formula (5) and the above general formula (6), R 4 ~R7 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, R 4 ~R 7 Two or more of these may be bonded to form a ring structure.

[0059] R 4 ~R 7 The hydrocarbon group represented by the formula (I) may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, and an alicyclic hydrocarbon group. The aliphatic groups in the aliphatic hydrocarbon group and the araliphatic 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, and aryl groups.

[0060] The alkyl group is preferably a lower alkyl group having 1 to 6 carbon atoms, and more preferably a lower alkyl group having 1 to 4 carbon atoms. Examples of such alkyl groups include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a cyclopentyl group, and a cyclohexyl group.

[0061] The alkenyl group is usually preferably a lower alkenyl group having 1 to 6 carbon atoms, and more preferably a lower alkenyl group having 1 to 4 carbon atoms. Examples of such alkenyl groups include a vinyl group, an n-propenyl group, an iso-propenyl group, an n-butenyl group, an iso-butenyl group, a sec-butenyl group, and a tert-butenyl group.

[0062] The aralkyl group is usually preferably one having a carbon number of 7 to 12. Examples of such aralkyl groups include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a phenylhexyl group, a methylbenzyl group, a methylphenethyl group, and an ethylbenzyl group.

[0063] The aryl group is preferably one having a carbon number of 6 to 14. Examples of such aryl groups include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,5-xylyl group, a naphthyl group, and an anthryl group.

[0064] The aromatic ring of the aryl group and the aralkyl group may have, as a substituent, 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 hydroxyl group, or the like.

[0065] The carboxy group and its salt include a functional group represented by the following general formula (7). -COO - M + ...(7) (M + represents a monovalent cation.)

[0066] In the above general formula (7), M + The monovalent cation represented by the formula: But, for example, H + , Li + , Na + , K + , NH4 + Examples include:

[0067] Component (D) is not particularly limited as long as it has 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, but it preferably has a structure represented by the following general formula (8). -N(CH2COO - M + ) n (R 8 ) n-3 ...(8) (In the above formula (8), R 8represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. + represents a monovalent cation. n represents an integer of 1 to 3.

[0068] In the above general formula (8), R 8 The hydrocarbon group represented by the formula (6) and (7) is R 4 ~R 7 In the above general formula (8), M + Examples of monovalent cations represented by the formula (I) include, but are not limited to, H + , Li + , Na + , K + , NH4 + Examples include:

[0069] When component (D) has a structure represented by the above general formula (8), component (D) effectively coordinates to and is adsorbed on the ruthenium surface to form a protective film, thereby making it possible to suppress excessive corrosion of the ruthenium site.

[0070] Examples of the component (D) include N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, N-(2-carboxyethyl)iminodiacetic acid, ethylenediaminetetraacetic acid, tetrasodium L-glutamate diacetate, 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, triethylenetetraamine hexaacetic acid, dihydroxyethylglycine, (S,S)-ethylenediamine disuccinic acid trihydrate, iminodiacetic acid, trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid hydrate, etc. These components (D) may be used alone or in combination of two or more.

[0071] The content (mass%) of component (D) is preferably 0.05 mass% or more, more preferably 0.1 mass% or more, and particularly preferably 0.15 mass% or more, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. The content (mass%) of component (D) is preferably 5 mass% or less, more preferably 2 mass% or less, and particularly preferably 1 mass% or less, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. When the content of component (D) is within the above range, excessive corrosion of the semiconductor substrate containing ruthenium may be effectively suppressed.

[0072] 1.5.Other Ingredients In addition to the components described above, the chemical mechanical polishing composition of this embodiment may contain, as necessary, 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 salt, a basic compound, etc.

[0073] <Liquid medium> The chemical mechanical polishing composition according to this embodiment contains a liquid medium. Examples of the liquid medium include water, a mixed medium of water and alcohol, and a mixed medium containing water and an organic solvent compatible with water. Among these, it is preferable to use water, a mixed medium of water and alcohol, and it is more preferable to use water. Pure water can be preferably used as the raw material of water. The liquid medium may be blended as the remainder of each of the above-mentioned components.

[0074] <Water-soluble polymer> The chemical mechanical polishing composition according to this embodiment may contain a water-soluble polymer. The water-soluble polymer may be adsorbed to the surface of the polished surface to reduce polishing friction, which may reduce the occurrence of dishing on the polished surface.

[0075] Specific examples of the water-soluble polymer include polycarboxylic acid, polystyrene sulfonic acid, polyacrylic acid, polymethacrylic acid, polyether, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyallylamine, hydroxyethyl cellulose, etc. These may be used alone or in combination of two or more.

[0076] 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 GPC (gel permeation chromatography).

[0077] When the chemical mechanical polishing composition according to this embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.001% by mass or more, more preferably 0.002% by mass or more, when the total mass of the chemical mechanical polishing composition is taken as 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, when the total mass of the chemical mechanical polishing composition is taken as 100% by mass.

[0078] <Nitrogen-containing heterocyclic compounds> The nitrogen-containing heterocyclic compound is an organic compound containing at least one heterocyclic ring selected from a five-membered heterocyclic ring and a six-membered heterocyclic ring, which has at least one nitrogen atom. Specific examples of the heterocyclic ring include a five-membered heterocyclic ring such as a pyrrole structure, an imidazole structure, and a triazole structure; and a six-membered heterocyclic ring such as a pyridine structure, a pyrimidine structure, a pyridazine structure, and a pyrazine structure. The heterocyclic ring 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 the heterocyclic compounds having such structures, a heterocyclic compound having a pyridine structure, a quinoline structure, a benzimidazole structure, and a benzotriazole structure is preferred.

[0079] Specific examples of the nitrogen-containing heterocyclic compound include aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indole, quinoline, isoquinoline, benzoisoquinoline, 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.These nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

[0080] <Surfactant> The surfactant is not particularly limited, and anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used. Examples of anionic surfactants include sulfates such as alkyl ether sulfates and polyoxyethylene alkyl phenyl ether sulfates; fluorine-containing surfactants such as perfluoroalkyl compounds; and the like. Examples of cationic surfactants include aliphatic amine salts and aliphatic ammonium salts. Examples of nonionic surfactants include nonionic surfactants having a triple bond such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohol. polyethylene glycol type surfactants, etc. These surfactants may be used alone or in combination of two or more.

[0081] <Organic acids and their salts> 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 the component (D)). The organic acids and salts thereof may be able to improve the polishing rate for a semiconductor substrate containing ruthenium due to a synergistic effect with the component (A).

[0082] As organic acid and its salt, it is preferable to use a compound having a carboxy group and a compound having a sulfo group.As the compound having a carboxy group, for example, stearic acid, lauric acid, oleic acid, myristic acid, alkenyl succinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, formic acid, acetic acid, oxalic acid, citric acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinolinic acid, quinaldic acid, amidosulfuric acid, propionic acid, trifluoroacetic acid; amino acids such as glycine, alanine, aspartic acid, glutamic acid, lysine, arginine, tryptophan, dodecylaminoethylaminoethylglycine, 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, and salts thereof. These compounds may be used alone or in combination of two or more.

[0083] When the chemical mechanical polishing composition according to this embodiment contains an organic acid (salt), the content of the organic acid (salt) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, based on the total mass of the chemical mechanical polishing composition being 100% by mass. The content of the organic acid (salt) is preferably 5% by mass or less, more preferably 1% by mass or less, based on the total mass of the chemical mechanical polishing composition being 100% by mass.

[0084] <Inorganic acids and their salts> 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 base added separately in the chemical mechanical polishing composition.

[0085] <Basic compounds> Examples of the basic compound include organic bases and inorganic bases. Examples of the organic base include amines, such as triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine, diglycolamine, and isopropylamine. Examples of the inorganic base include ammonia, potassium hydroxide, and sodium hydroxide. Among these basic compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used alone or in combination of two or more.

[0086] 1.6.pH The pH of the chemical mechanical polishing composition according to this embodiment is preferably 6.0 or more, more preferably 6.5 or more, and particularly preferably 7.0 or more. 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. When the pH is within the above range, the generation of ruthenium tetroxide gas and the corrosion of ruthenium may be effectively suppressed.

[0087] The pH of the chemical mechanical polishing composition can be adjusted by adding, for example, the aforementioned organic acids (salts), inorganic acids (salts), basic compounds, etc., and one or more of these can be used.

[0088] In the present invention, pH refers to hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, a benchtop pH meter manufactured by Horiba, Ltd.).

[0089] 1.7. Method for preparing a chemical mechanical polishing composition The chemical mechanical polishing composition according to this embodiment can be prepared by dissolving or dispersing the above-mentioned components in a liquid medium such as water. The method of dissolving or dispersing is not particularly limited, and any method may be used as long as it can dissolve or disperse uniformly. In addition, the order and method of mixing the above-mentioned components are not particularly limited.

[0090] The chemical mechanical polishing composition can also be prepared as a concentrated stock solution and diluted with a liquid medium such as water when used.

[0091] 2. Polishing method A polishing method according to one embodiment of the present invention includes a step of polishing a semiconductor substrate using the above-mentioned chemical mechanical polishing composition. The chemical mechanical polishing composition can perform chemical mechanical polishing of a semiconductor substrate containing ruthenium while maintaining a stable polishing rate while suppressing corrosion of ruthenium. Therefore, it is preferable that the semiconductor substrate to be treated has a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys. Hereinafter, the polishing method according to this embodiment will be described in detail with reference to Figs. 1 to 4.

[0092] An example of a semiconductor substrate having a portion made of at least one selected from the group consisting of ruthenium and ruthenium alloys is a process target 100 as shown in Fig. 1. Fig. 1 shows a schematic cross-sectional view of the process target 100. The process target 100 is produced through the following steps (1) to (4).

[0093] (1) First, a base 10 is prepared as shown in Fig. 1. The base 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 base 10. Next, a silicon oxide film 12, which is an insulating film, is formed on the base 10 by using a thermal oxidation method.

[0094] (2) Next, the silicon oxide film 12 is patterned. Using the obtained pattern as a mask, wiring grooves 14 are formed in the silicon oxide film 12 by photolithography.

[0095] (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 groove 14. The ruthenium-containing film 16 can be formed by, for example, chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a ruthenium precursor, or physical vapor deposition (PVD) such as sputtering.

[0096] (4) Next, a copper film 18 having a thickness of 10,000 to 15,000 Å (here, "Å" refers to 0.1 nm) is deposited by chemical vapor deposition or electroplating. As the material for the copper film 18, not only high purity copper but also an alloy containing copper can be used. The copper content in the alloy containing copper is preferably 95 mass % or more.

[0097] Next, a first polishing step is performed on the workpiece 100. FIG. 2 shows the workpiece 100 after the first polishing step is completed. 2 is a cross-sectional view showing a schematic diagram of a polishing body 100. As shown in Fig. 2, in the first polishing step, a copper film 18 is polished using a composition for chemical mechanical polishing of a copper film until a ruthenium-containing film 16 is exposed. Examples of the composition for chemical mechanical polishing of a copper film include an aqueous dispersion for chemical mechanical polishing described in JP2010-153790A.

[0098] Next, a second polishing step is performed on the workpiece 100. Fig. 3 is a cross-sectional view showing the workpiece 100 at the end of the second polishing step. As shown in Fig. 3, in the second polishing step, the ruthenium-containing film 16, the copper film 18, and a part of the silicon oxide film 12 are polished using the chemical mechanical polishing composition of the present invention.

[0099] In the first and second polishing steps, for example, a polishing apparatus 200 as shown in Fig. 4 can be used. Fig. 4 is a perspective view that shows the polishing apparatus 200. The first and second polishing steps are performed by supplying a slurry (composition for chemical mechanical polishing) 44 from a slurry supply nozzle 42 and contacting a carrier head 52 holding a semiconductor substrate 50 with a turntable 48 to which a polishing pad 46 is attached while rotating the turntable 48. Note that Fig. 4 also shows a water supply nozzle 54 and a dresser 56.

[0100] The material of the polishing pad 46 may be any of a polyurethane foam type, a nonwoven fabric type, and a suede type, but is preferably a polyurethane foam type.

[0101] The polishing load of carrier head 52 can be selected within a range of 0.7 to 70 psi, and preferably 1.5 to 35 psi. The rotation speed of turntable 48 and carrier head 52 can be appropriately selected within a range of 10 to 400 rpm, and preferably 30 to 150 rpm. The lower limit of the flow rate of the chemical mechanical polishing composition supplied from slurry supply nozzle 42 is 15 mL / min, and preferably 50 mL / min, and the upper limit of the flow rate is 400 mL / min, and preferably 300 mL / min.

[0102] Examples of commercially available polishing machines include Ebara Corporation's models "EPO-112" and "F-REX300SII"; Lapmaster SFT's models "LGP-510" and "LGP-552"; Applied Materials' models "Mirra" and "Reflexion"; G&P Technology's model "POLI-400L"; and AMAT's model "Reflexion LK".

[0103] 3. Working Example The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0104] 3.1. Preparation of silica particle aqueous dispersion 3.1.1. Preparation of Water Dispersion A 25% aqueous ammonia (manufactured by Fujifilm Wako Pure Chemical Industries) was added to 2000 g of PL-3 (manufactured by Fuso Chemical Co., Ltd., 19.5% colloidal silica dispersion liquid) and adjusted to pH 9. Then, 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. Then, 50 g of hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries) was added and refluxed under normal pressure for 8 hours to obtain an aqueous dispersion A containing cocoon-shaped silica particles surface-modified with sulfo groups having an average particle size of 58 nm.

[0105] 3.1.2. Preparation of Water Dispersion B 2000 g of PL-3 (Fuso Chemical Co., Ltd., 19.5% colloidal silica dispersion) was heated to 60°C. Then, (3-triethoxysilyl)propylsuccinic anhydride (Tokyo Chemical Industry Co., Ltd.) was added. C. for an additional 4 hours of stirring, to obtain an aqueous dispersion B containing cocoon-shaped silica particles having an average particle size of 60 nm and surface-modified with carboxy groups.

[0106] 3.1.3. Preparation of Water Dispersion C A mixture of 70 g of methanol and 11.3 g of 3-aminopropyltriethoxysilane (Tokyo Chemical Industry Co., Ltd.) was added dropwise to 2000 g of PL-3 (Fuso Chemical Co., Ltd., 19.5% colloidal silica dispersion) and refluxed for 2 hours under normal pressure. After that, pure water was added dropwise while keeping the volume constant, and the addition of pure water was stopped when the tower top temperature reached 100°C, obtaining aqueous dispersion C containing cocoon-shaped silica particles with an average particle size of 56 nm and surface-modified with amino groups.

[0107] 3.1.4. Preparation of Water Dispersion D 25% aqueous ammonia (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to 1950 g of PL-2L (manufactured by Fuso Chemical Co., Ltd., 20% colloidal silica dispersion liquid) and adjusted to pH 9. Then, 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 dropped and 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 under normal pressure for 8 hours to obtain an aqueous dispersion D containing spherical silica particles surface-modified with sulfo groups having an average particle size of 23 nm.

[0108] 3.1.5. Preparation of Water Dispersion E PL-3 (19.5% colloidal silica dispersion, manufactured by Fuso Chemical Co., Ltd.) was used as it was as aqueous dispersion E containing surface-unmodified silica particles having an average particle diameter of 60 nm.

[0109] 3.2. Preparation of Chemical Mechanical Polishing Composition The components were mixed to obtain the compositions shown in Tables 1 to 3, and an aqueous potassium hydroxide solution (manufactured by Kanto Chemical Co., Ltd., product name "48% aqueous potassium hydroxide solution") and phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "phosphoric acid") were added as necessary to obtain the pH values ​​shown in Tables 1 to 3. Pure water was added so that the total amount of all components was 100 mass %, to prepare chemical mechanical polishing compositions for each Example and Comparative Example. For each chemical mechanical polishing composition obtained in this manner, the zeta potential of the abrasive grains was measured using a zeta potential measuring device (manufactured by Dispersion Technology Inc., model "DT300"), and the results are shown in Tables 1 to 3.

[0110] 3.3.Evaluation Methodology 3.3.1. Evaluation of polishing speed Using the chemical mechanical polishing composition prepared above, a chemical mechanical polishing test was carried out under the following conditions, using a 12 inch diameter wafer with a 100 nm thick ruthenium film as the polishing target. (polishing conditions) Polishing equipment: Ebara Corporation, model "F-REX300SII" Polishing pad: DuPont "Porous polyurethane pad; Optivisiоn 9500 CMP Polishing pad" ·Chemical mechanical polishing composition supply rate: 250mL / min Platen rotation speed: 100 rpm Head rotation speed: 90 rpm Head pressure: 2psi ·Polishing time: 60 seconds Polishing rate (nm / min) = (film thickness before polishing (nm) - film thickness after polishing (nm)) / polishing time (min)

[0111] The thickness of the ruthenium film was measured by measuring the resistance using a resistivity meter (KLA-Tencor, model "RS-100") with a DC four-probe method, and the sheet resistance was compared with the thickness of the ruthenium. It was calculated from the volume resistivity using the following formula. Ruthenium film thickness (nm) = [Ruthenium film volume resistivity (Ω·m) ÷ Sheet resistance (Ω / sq)] × 10 9

[0112] The evaluation criteria for the polishing rate of the ruthenium film are as follows: The evaluation results of the polishing rate of the ruthenium film are shown in Tables 1 to 3. (Evaluation Criteria) A: When the polishing speed was 1000 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 1000 nm / min, it was judged to be good since it could be used in practical applications. C: When the polishing rate was less than 50 nm / min, the polishing rate was too low for practical use and was therefore judged to be poor.

[0113] 3.3.2. 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 cut to 30 mm x 10 mm was immersed for 5 minutes. The wafer piece was then taken out and washed with running water, and the thickness of the ruthenium film was measured in the same manner as in "3.3.1. Evaluation of polishing rate" above. The etching rate was calculated from the change in the thickness of the ruthenium film before and after 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)

[0114] The evaluation criteria for the etching rate of the ruthenium film are as follows: The evaluation results of the etching rate of the ruthenium film are shown in Tables 1 to 3. (Evaluation Criteria) A: If the etching rate is less than 1.5 nm / min, it is judged as 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 since it could be used in practical applications. C: When the etching rate was 3 nm / min or more, the etching rate was too high to be practically practical, and the sample was therefore judged to be poor.

[0115] 3.3.3. Storage stability evaluation The chemical mechanical polishing composition prepared above was stored in a thermostatic storage cabinet at 20° C. for 3 or 7 days, and then a chemical mechanical polishing test was performed under the same polishing conditions as in "3.3.1. Evaluation of polishing rate" above, using a 12-inch diameter wafer with a 100 nm ruthenium film as the polishing target. The rate of change in the polishing rate of the ruthenium film before and after storage was calculated using the following formula. Fluctuation rate (%)=|((polishing rate calculated in “3.3.1. Evaluation of polishing rate”)−(polishing rate when the chemical mechanical polishing composition after storage was used)) / (polishing rate calculated in “3.3.1. Evaluation of polishing rate”)×100|

[0116] The evaluation criteria for the rate of change are as follows: The evaluation results of the storage stability of the chemical mechanical polishing composition are shown in Tables 1 to 3. (Evaluation Criteria) A: When the fluctuation rate of the polishing speed after 7 days of storage was less than 10%, it was judged to be very good. B: When the rate of change in the polishing speed after 3 days of storage was less than 10%, but the rate of change in the polishing speed after 7 days of storage was 10% or more, it was judged to be good since it could be used in practical applications. C: When the fluctuation rate of the polishing speed after 3 days of storage was 10% or more, it was judged to be poor because it was difficult to use.

[0117] 3.4.Evaluation Results Tables 1 to 3 show the compositions of the chemical mechanical polishing compositions used in each of the Examples and Comparative Examples, as well as the evaluation results.

[0118] [Table 1]

[0119] [Table 2]

[0120] [Table 3]

[0121] The following products or reagents were used for each component in Tables 1 to 3 above. <Component (A)> Aqueous dispersions A to E: Aqueous dispersions A to E prepared in the above section "3.1. Preparation of silica particle aqueous dispersion." <Ingredient (B)> ·H5IO6 (periodic acid): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "orthoperiodic acid" ·KClO (potassium hypochlorite): Manufactured by Kanto Chemical Industries, Ltd., product name "potassium hypochlorite solution" ·KClO2 (potassium chlorite): Manufactured by Angene, product name "Potassium Chlorite" NaBrO (sodium hypobromite): manufactured by Kanto Chemical Co., Ltd., product name "sodium hypobromite" <Ingredient (C)> Hydrogen peroxide: Fujifilm Wako Pure Chemical Industries, 30% aqueous solution <Ingredient (D)> N-(phosphonomethyl)iminodiacetic acid: Sigma-Aldrich, trade name "N-(phosphonomethyl)iminodiacetic acid hydrate" Hydroxyethyliminodiacetic acid: Tokyo Chemical Industry Co., Ltd., product name "N-(2-Hydroxyethyl)iminodiacetic Acid" N-(2-Carboxyethyl)iminodiacetic acid: Tokyo Chemical Industry Co., Ltd., product name "N-(2-Carboxyethyl)iminodiacetic Acid" Nitrilotriacetic acid: Tokyo Chemical Industry Co., Ltd., product name "Nitrilotriacetic Acid" 3,3',3''-Nitrilopropionic Acid: Manufactured by Tokyo Chemical Industry Co., Ltd., trade name "3,3',3''-Nitrilopropionic Acid" Ethylenediaminetetraacetic acid: Tokyo Chemical Industry Co., Ltd., product name "Ethylenediaminetetraacetic Acid" Hydroxyethylethylenediaminetriacetic acid: Tokyo Chemical Industry Co., Ltd., product name "N-(2-Hydroxyethyl)ethylenediamine-N,N',N'-triacetic Acid" <Other ingredients> KIO3 (potassium iodate): Manufactured by Fujifilm Wako Pure Chemical Industries, product name "potassium iodate" (NH4)2S2O8 (ammonium peroxodisulfate): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "ammonium peroxodisulfate" 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., product name "1-Hydroxyethane-1,1-diphosphonic Acid (ca. 60% in Water, ca. 4.2mol / L)"

[0122] According to the chemical mechanical polishing compositions of Examples 1 to 15, which use a combination of component (A) having a specific functional group and component (B) containing a specific anion species, it is found that component (A) is easily adsorbed to the ruthenium film, and component (B) effectively oxidizes the ruthenium film, thereby improving the polishing rate of the ruthenium film and suppressing corrosion of the ruthenium film. It is also found that the use of component (A) having a specific functional group increases the repulsive force between abrasive grains in the chemical mechanical polishing composition, suppressing aggregation of the abrasive grains, thereby improving storage stability.

[0123] In contrast, the chemical mechanical polishing compositions of Comparative Examples 1 to 5 and 8 to 9, which contain abrasive grains having no specific functional groups, show poor results in at least one of the polishing rate evaluation, etching rate evaluation, and storage stability evaluation, and are difficult to put to practical use. Also, the chemical mechanical polishing compositions of Comparative Examples 6 to 7, which contain a compound not containing a specific anion species, show a low polishing rate for the ruthenium film because they cannot effectively oxidize ruthenium.

[0124] 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 those described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments, or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0125] 10...substrate, 12...silicon oxide film, 14...wiring groove, 16...ruthenium-containing film, 18...copper film, 42...slurry supply nozzle, 44...slurry (composition for chemical mechanical polishing), 46...polishing pad, 48...turntable, 50...semiconductor substrate, 52...carrier head, 54...water supply nozzle, 56...dresser, 100...processing target, 200...polishing device

Claims

1. Abrasive grains (A); Periodate ion (IO ４ － ), hypochlorite ion (ClO － ), chlorite ion (ClO ２ － ) and hypobromite ion (BrO － (B) an acid or a salt thereof containing at least one anion selected from the group consisting of Hydrogen peroxide (C), The abrasive grains (A) have at least one functional group selected from the functional groups represented by the following general formulas (1) to (4), For 1 L of chemical mechanical polishing composition, The component (B) is 0.001 mol / L or more and 0.05 mol / L or less, The component (C) is 0.0005 mol / L or more and 0.5 mol / L or less. A chemical mechanical polishing composition comprising: -SO ３ － M ＋ ・・・・・(1) -COO － M ＋ ・・・・・(2) (In the above formulas (1) and (2), M ＋ represents a monovalent cation.) -NR １ R ２ ・・・・・・(3) -N ＋ R １ R ２ R ３ M － ・・・・・(4) (In the above formulas (3) and (4), R １ , R ２ and R ３ Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － represents an anion.)

2. Abrasive grains (A); Periodate ion (IO ４ － ), hypochlorite ion (ClO － ), chlorite ion (ClO ２ － ) and hypobromite ion (BrO － (B) an acid or a salt thereof containing at least one anion selected from the group consisting of and a compound (D) having at least one functional group selected from the group consisting of an amino group and a salt thereof, and at least one functional group selected from the group consisting of a carboxy group and a salt thereof, The abrasive grains (A) are each independently selected from the functional groups represented by the following general formulas (1) to (4): having one functional group, The component (D) is at least one selected from the group consisting of N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, N-(2-carboxyethyl)iminodiacetic acid, nitrilotriacetic acid, 3,3',3''-nitrilotripropionic acid, ethylenediaminetetraacetic acid, and hydroxyethylethylenediaminetriacetic acid. -SO ３ － M ＋ ・・・・・(1) -COO － M ＋ ・・・・・(2) (In the above formulas (1) and (2), M ＋ represents a monovalent cation.) -NR １ R ２ ・・・・・・(3) -N ＋ R １ R ２ R ３ M － ・・・・・(4) (In the above formulas (3) and (4), R １ , R ２ and R ３ Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － represents an anion.)

3. 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.

4. The chemical mechanical polishing composition of claim 1, further comprising a compound (D) having at least one functional group selected from the group consisting of an amino group and its salt, and at least one functional group selected from the group consisting of a carboxy group and its salt.

5. The chemical mechanical polishing composition of claim 1 , having a pH of 6 or more and 12 or less.

6. A polishing method comprising the step of polishing a semiconductor substrate with the chemical mechanical polishing composition according to claim 1 .

7. 7. The polishing method according to claim 6, wherein the semiconductor substrate comprises a portion made of at least one material selected from the group consisting of ruthenium and ruthenium alloys.

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