Chemical mechanical polishing composition and polishing method

Abstract

The present invention provides a chemical mechanical polishing composition with which it is possible to suppress ruthenium corrosion and also perform chemical mechanical polishing of a semiconductor substrate containing ruthenium while maintaining a stable polishing speed.　The composition for chemical mechanical polishing of the present invention contains: (A) abrasive grains; (B) an acid containing at least one anion selected from the group consisting of periodate ions (IO4 –), hypochlorite ions (CIO–), chlorite ions (CIO2 –) and hypobromite ions (BrO–) or a salt of said acid; and (C) hydrogen peroxide. MB / MC = 0.015 to 11, where MB (mol / L) is the amount of the (B) acid or salt thereof and MC (mol / L) is the amount of hydrogen peroxide (C).

Description

[Technical Field]

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

[0002] With advancements in semiconductor integrated circuit manufacturing technology, there is a growing demand for higher integration and faster operation of semiconductor devices. Consequently, the flatness of the semiconductor substrate surface required in the manufacturing process of fine circuits in semiconductor devices has become more stringent, making chemical mechanical polishing (CMP) an indispensable technology in semiconductor device manufacturing.

[0003] CMP (Chemical Mechanical Polishing) 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 surface plate, pressing the semiconductor substrate against it, and sliding the semiconductor substrate and the polishing pad against each other. In CMP, the surface irregularities of the semiconductor substrate 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 creating copper wiring in semiconductor substrates manufactured via such CMP (see, for example, Patent Documents 1-3). [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 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In such CMP (Chemical Polishing), in order to suppress the generation of highly volatile ruthenium tetroxide gas and polish areas containing ruthenium, it is necessary to perform chemical mechanical polishing using a basic chemical mechanical polishing composition and a halogen-based oxidizing agent with high oxidizing power, such as potassium periodate or potassium hypochlorite. However, while using a basic chemical mechanical polishing composition can suppress the generation of ruthenium tetroxide gas, insufficiently oxidized ruthenium oxide adheres to the surface of the polishing pad, degrading the polishing characteristics of the polishing pad. As a result, it becomes difficult to perform chemical mechanical polishing of semiconductor substrates containing ruthenium while maintaining a stable polishing speed. On the other hand, using a halogen-based oxidizing agent with high oxidizing power may corrode the ruthenium.

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

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

[0009] One embodiment of the chemical mechanical polishing composition according to the present invention is: Abrasive grain (A) and Periodate ion (IO4 - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 - ) and hypobromite ions (BrO - An acid or a salt thereof (B) containing at least one anion selected from the group consisting of ), It contains hydrogen peroxide (C) and If the content of the acid or its salt (B) is MB (mol / L) and the content of the hydrogen peroxide (C) is MC (mol / L), then MB / MC = 0.015 to 11.

[0010] In one embodiment of the chemical mechanical polishing composition, the abrasive grains (A) may have a functional group represented by the following general formula (1) or (2). -SO3 - M + ·····(1) -COO - M + ·····(2) (M + represents a monovalent cation.)

[0011] In one embodiment of the chemical mechanical polishing composition, the abrasive grains (A) may have a functional group represented by the following general formula (3) or (4). -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. M - represents an anion.)

[0012] In any embodiment of the chemical mechanical polishing composition, the absolute value of the zeta potential of the abrasive grains (A) in the chemical mechanical polishing composition may be 10 mV or more.

[0013] In any embodiment of the chemical mechanical polishing composition, the MB (mol / L) may be 0.001 to 0.05 mol / L.

[0014] In any embodiment of the chemical mechanical polishing composition, the pH may be 6 or more and 12 or less.

[0015] One aspect of the polishing method according to the present invention is: The process includes polishing a semiconductor substrate using a chemical mechanical polishing composition according to any of the above embodiments.

[0016] In one embodiment of the polishing method, The semiconductor substrate may include portions made of at least one material selected from the group consisting of ruthenium and ruthenium alloys. [Effects of the Invention]

[0017] According to the chemical mechanical polishing composition of the present invention, chemical mechanical polishing of a semiconductor substrate containing ruthenium can be performed while suppressing the corrosion of ruthenium and maintaining a stable polishing speed. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic cross-sectional view showing a workpiece suitable for use in the polishing process according to this embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view of the workpiece at the end of the first polishing process. [Figure 3] Figure 3 is a schematic cross-sectional view of the workpiece at the end of the second polishing process. [Figure 4] Figure 4 is a schematic perspective view of a chemical mechanical polishing apparatus. [Modes for carrying out the invention]

[0019] Preferred embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below, and includes various modifications that do not alter the essence of the invention.

[0020] In this specification, numerical ranges described as "A to B" are interpreted as including numerical A as the lower limit and numerical B as the upper limit.

[0021] 1. Chemical mechanical polishing composition A chemical mechanical polishing composition according to one embodiment of the present invention comprises abrasive grains (A) (hereinafter also referred to as "component (A)") and periodate ions (IO4 - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 - ) and hypobromite ions (BrO - The present invention provides an acid or salt (B) (hereinafter also referred to as "component (B)") containing at least one anion selected from the group consisting of ), and hydrogen peroxide (C) (hereinafter also referred to as "component (C)"), wherein the MB / MC ratio is 0.015 to 11, where MB is the content of the acid or salt (B) and MC is the content of the hydrogen peroxide (C) (mol / L). The components included in the chemical mechanical polishing composition according to this embodiment will be described in detail below.

[0022] 1.1. Ingredients (A) The chemical mechanical polishing composition according to this embodiment contains abrasive particles (A). Examples of component (A) include inorganic particles such as silica, ceria, alumina, zirconia, and titania, with silica particles being preferred. Examples of silica particles include fumed silica and colloidal silica, with colloidal silica being preferred. Colloidal silica is preferably used from the viewpoint of reducing polishing defects such as scratches. For example, colloidal silica produced by the method described in Japanese Patent Application Publication No. 2003-109921 can be used.

[0023] If component (A) is silica particles with silica as the main component, it may also contain other components. Examples of other components include aluminum compounds and silicon compounds. By further containing aluminum compounds or silicon compounds in the silica particles, the surface hardness of the silica particles can be reduced, which may allow for a more stable polishing speed while further reducing the occurrence of polishing scratches and dishing on the polished surface.

[0024] Examples of aluminum compounds include aluminum hydroxide, aluminum oxide (alumina), aluminum chloride, aluminum nitride, aluminum acetate, aluminum phosphate, aluminum sulfate, sodium aluminate, and potassium aluminate. On the other hand, examples of silicon compounds include silicon nitride, silicon carbide, silicates, silicones, and silicon resins.

[0025] The shape of component (A) is not particularly limited and may be spherical, cocoon-shaped, chain-spherical, or have multiple protrusions on its surface. Abrasive grains having multiple protrusions on their surface can be manufactured, for example, by applying the methods described in Japanese Patent Publication No. 2007-153732 and Japanese Patent Publication No. 2013-121631.

[0026] 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 repulsion between abrasive grains effectively prevents aggregation of particles, and the ruthenium-containing semiconductor substrate can be polished at a more stable polishing speed. Examples of zeta potential measuring devices include the "ELSZ-2000ZS" from Otsuka Electronics Co., Ltd., the "Zetasizer Ultra" from Malvern, Inc., and the "DT300" from Dispersion Technology Inc.

[0027] The content of 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 considered 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 considered as 100% by mass. When the content of component (A) is within the above range, semiconductor substrates containing ruthenium can be polished at a stable polishing speed, and the storage stability of the chemical mechanical polishing composition may be good.

[0028] Component (A) is preferably an abrasive grain in which at least a portion of its surface is modified with a functional group. Abrasive grains in which at least a portion of their surface is modified with a functional group have a larger absolute value of zeta potential compared to abrasive grains that are not surface-modified with a functional group, thus increasing the electrostatic repulsive force between abrasive grains. As a result, the dispersibility of abrasive grains in the chemical mechanical polishing composition is improved, enabling high-speed polishing while reducing the occurrence of polishing scratches and dishing.

[0029] Component (A) may have a functional group represented by the following general formula (1), for example. -SO3 - M + ...(1) (M + (This represents a monovalent cation.)

[0030] In the above general formula (1), M + The monovalent cations represented by are not limited to these, but for example, H + Li + kaNa + , K + NH4 + These are examples. In other words, the functional group represented by the above general formula (1) can also be rephrased as "at least one functional group selected from the group consisting of sulfo groups and their salts." Here, "salt of a sulfo group" refers to a salt in which the hydrogen ions contained in the sulfo group (-SO3H) are Li + kaNa + , K + NH4 + This refers to a functional group substituted with a monovalent cation such as . Component (A) having the functional group represented by the above general formula (1) is an abrasive grain in which the functional group represented by the above general formula (1) is fixed to its surface via covalent bonds, and does not include abrasive grains in which a compound having the functional group represented by the above general formula (1) is physically or ionically adsorbed to its surface.

[0031] Component (A) having the functional group represented by the above general formula (1) can be produced as follows. First, silica prepared by a known method and a mercapto group-containing silane coupling agent are thoroughly stirred in an acidic medium to covalently bond the mercapto group-containing silane coupling agent to the surface of the silica. Examples of mercapto group-containing silane coupling agents include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Next, a suitable amount of hydrogen peroxide is added and allowed to stand for a sufficient amount of time to obtain component (A) having the functional group represented by the above general formula (1).

[0032] The zeta potential of component (A), which has a functional group represented by the above general formula (1), is negative in the chemical mechanical polishing composition, and its negative potential is preferably -10mV or less, more preferably -15mV or less, and particularly preferably -20mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion force between abrasive grains effectively prevents aggregation of particles, and in some cases, semiconductor substrates containing ruthenium can be polished at a more stable polishing speed. The zeta potential measuring device can be the one described above. 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, etc.

[0033] When the chemical mechanical polishing composition according to this embodiment contains component (A) having a functional group represented by the general formula (1) above, the content of component (A) is preferably 0.5% by mass or more, and more preferably 1% by mass or more, when the total mass of the chemical mechanical polishing composition is 100% by mass. The content of component (A) is preferably 10% by mass or less, and more preferably 5% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass. When the content of component (A) having a functional group represented by the general formula (1) above is within the above range, semiconductor substrates containing ruthenium can be polished at a stable polishing speed, and the storage stability of the chemical mechanical polishing composition may be good.

[0034] Component (A) may have, for example, a functional group represented by the following general formula (2). -COO - M + ...(2) (M + (This represents a monovalent cation.)

[0035] In the above general formula (2), M + The monovalent cations represented by are not limited to these, but for example, H + Li + kaNa + , K + NH4 + These are examples. In other words, the functional group represented by the above general formula (2) can also be rephrased as "at least one functional group selected from the group consisting of carboxyl groups and their salts." Here, "salt of a carboxyl group" refers to a salt in which the hydrogen ions contained in the carboxyl group (-COOH) are Li + kaNa + , K + NH4 + This refers to a functional group substituted with a monovalent cation such as . Component (A) having the functional group represented by the above general formula (2) is an abrasive grain in which the functional group represented by the above general formula (2) is fixed to its surface via covalent bonds, and does not include abrasive grains in which a compound having the functional group represented by the above general formula (2) is physically or ionically adsorbed to its surface.

[0036] 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 carboxylic acid anhydride-containing silane coupling agent are thoroughly stirred in a basic medium, and the carboxylic acid anhydride-containing silane coupling agent is covalently bonded to the surface of the abrasive grains to obtain abrasive grains having the functional group represented by the above general formula (2). Here, examples of carboxylic acid anhydride-containing silane coupling agents include 3-(triethoxysilyl)propyl succinic anhydride.

[0037] The zeta potential of component (A) having the functional group represented by the general formula (2) above is negative in the chemical mechanical polishing composition, and this negative potential is preferably -10mV or less, more preferably -15mV or less, and particularly preferably -20mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion force between abrasive grains effectively prevents aggregation of particles, and in some cases, semiconductor substrates containing ruthenium can be polished at a more stable polishing speed. The zeta potential measuring device can be the device described above. The zeta potential of component (A) having the functional group represented by the general formula (2) above can be adjusted by appropriately increasing or decreasing the amount of the carboxylic acid anhydride-containing silane coupling agent, etc., added as described above.

[0038] When the chemical mechanical polishing composition according to this embodiment contains component (A) represented by the above general formula (2), the content of 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 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 100% by mass. When the content of component (A) is within the above range, semiconductor substrates containing ruthenium can be polished at a stable polishing speed, and the storage stability of the chemical mechanical polishing composition may be good.

[0039] Component (A) may have, for example, 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 equations (3) and (4) above, R 1 , R 2 and R 3Each of these independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - (This represents an anion.)

[0040] The functional group represented by the above general formula (3) represents an amino group, and the functional group represented by the above general formula (4) represents a salt of an amino group. Therefore, the functional group represented by the above general formula (3) and the functional group represented by the above general formula (4) can be collectively rephrased as "at least one functional group selected from the group consisting of amino groups and salts thereof." Component (A) having the functional group represented by the above general formula (3) and / or the above general formula (4) is an abrasive grain on which the functional group represented by the above general formula (3) and / or the above general formula (4) is fixed to its surface via covalent bonds, and does not include abrasive grains on which a compound having the functional group represented by the above general formula (3) and / or the above general formula (4) is physically or ionically adsorbed to its surface.

[0041] In the above general formula (4), M - The anions represented by these are not limited to these, but for example, OH - F - Cl - , Br - , I - 5CN - In addition to anions such as those mentioned above, anions derived from acidic compounds can also be cited.

[0042] In the above general formulas (3) and (4), R 1 ~R 3 Each of these independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, but R 1 ~R 3 Two or more of these may be bonded together to form a ring structure.

[0043] R 1 ~R 3The hydrocarbon group represented by may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aromatic aliphatic hydrocarbon group, or an alicyclic hydrocarbon group. Furthermore, the aliphatic group 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, and aryl groups.

[0044] As the alkyl group, a lower alkyl group having 1 to 6 carbon atoms is preferred, and a lower alkyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, cyclopentyl group, and cyclohexyl group.

[0045] As the alkenyl group, a lower alkenyl group having 1 to 6 carbon atoms is preferred, and a lower alkenyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkenyl groups include vinyl group, n-propenyl group, iso-propenyl group, n-butenyl group, iso-butenyl group, sec-butenyl group, tert-butenyl group, and the like.

[0046] As for the aralkyl group, those with 7 to 12 carbon atoms are preferred. Examples of such aralkyl groups include benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, phenylhexyl group, methylbenzyl group, methylphenethyl group, and ethylbenzyl group.

[0047] The aryl group is preferably one having 6 to 14 carbon atoms. Examples of such aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3,5-xylyl, naphthyl, and anthyl groups.

[0048] The aromatic rings of the aryl and aralkyl groups described above may have substituents such as lower alkyl groups like methyl or ethyl groups, halogen atoms, nitro groups, amino groups, or hydroxyl groups.

[0049] Component (A) having the functional group represented by the above general formula (3) and / or the above general formula (4) can be produced, for example, by 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 above general formula (3) and / or the above general formula (4). Examples of amino group-containing silane coupling agents include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0050] The zeta potential of component (A) having the functional group represented by the above general formula (3) and / or the above general formula (4) is negative in the chemical mechanical polishing composition, and the negative potential is preferably -10 mV or less, and more preferably -15 mV or less. When the zeta potential of component (A) is within the above range, the electrostatic repulsion force between abrasive grains effectively prevents aggregation of particles, and in some cases, semiconductor substrates containing ruthenium can be polished at a more stable polishing speed. The zeta potential measuring device can be the device described above. The zeta potential of component (A) having the functional group represented by the above general formula (3) and / or the above general formula (4) can be adjusted by appropriately increasing or decreasing the amount of the above-mentioned amino group-containing silane coupling agent, etc.

[0051] When the chemical mechanical polishing composition according to this embodiment contains a component (A) having a functional group represented by the above general formula (3) and / or the above 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 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 100% by mass. When the content of component (A) is within the above range, semiconductor substrates containing ruthenium can be polished at a stable polishing speed, and the storage stability of the chemical mechanical polishing composition may be good.

[0052] 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 ions (BrO - The product contains an acid or a salt (B) containing at least one anion selected from the group consisting of (hereinafter also referred to as "specific anion species"). The anion contained in component (B) is presumed to function as an oxidizing agent, oxidizing ruthenium and promoting polishing.

[0053] 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 hypobromous acid, etc. Among these, at least one compound selected from the group consisting of periodic acid, potassium chlorite, potassium hypochlorite, and sodium hypobromous acid is preferred, with periodic acid being more preferred. Component (B) may be used alone or in combination of two or more.

[0054] The content of component (B) [MB (mol / L)] 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 of component (B) [MB (mol / L)] 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, it may be possible to oxidize ruthenium to promote polishing, prevent excessive reaction between ruthenium and specific anion species, and suppress ruthenium corrosion.

[0055] The content (mass%) of component (B) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, when the total mass of the chemical mechanical polishing composition is considered as 100% by mass. The content (mass%) of component (B) is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 7% by mass or less, when the total mass of the chemical mechanical polishing composition is considered as 100% by mass. When the content of component (B) is within the above range, it may be possible to oxidize ruthenium to promote polishing, prevent excessive reaction between ruthenium and specific anion species, and suppress ruthenium corrosion.

[0056] 1.3.Component (C) The chemical mechanical polishing composition according to this embodiment contains hydrogen peroxide (C). Hydrogen peroxide (C) oxidizes ruthenium to promote polishing, and by reacting with ruthenium, component (C) prevents excessive reaction between ruthenium and specific anionic species contained in component (B), thereby suppressing the generation of halogen gas and corrosion of ruthenium.

[0057] The content of component (C) [MC (mol / L)] 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 of component (C) [MC (mol / L)] 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, it may be possible to oxidize ruthenium to promote polishing, and at the same time, the reaction of component (C) with ruthenium may prevent excessive reaction between ruthenium and specific anion species contained in component (B), thereby suppressing ruthenium corrosion.

[0058] 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, it may be possible to oxidize ruthenium to promote polishing, and at the same time, the reaction of component (C) with ruthenium may prevent excessive reaction between ruthenium and specific anion species contained in component (B), thereby suppressing ruthenium corrosion.

[0059] When the content of the acid or its salt (B) is MB (mol / L) and the content of the hydrogen peroxide (C) is MC (mol / L), the value of MB / MC is preferably 0.015 or more, more preferably 0.02 or more, and particularly preferably 0.1 or more. The value of MB / MC is preferably 11 or less, more preferably 10.5 or less, and particularly preferably 10 or less. When the value of MB / MC is within the above range, ruthenium can be oxidized to promote polishing, and the component (C) can react with ruthenium to prevent an excessive reaction between ruthenium and specific anion species contained in the component (B), and corrosion of ruthenium may be suppressed.

[0060] 1.4. Component (D) The chemical mechanical polishing composition according to the present embodiment may contain a compound (D) (also referred to as "component (D)" in this specification) 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 carboxyl group and its salt.

[0061] Examples of the amino group and its salt include functional groups represented by the following general formula (5) or the following general formula (6). -NR 4 R 5 ·····(5) -N + R 4 R 5 R 6 M - ·····(6) (In the above formula (5) and the above formula (6), R 4 , R 5 , and R 6 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group. M - represents an anion.)

[0062] In the above general formula (5) and the above general formula (6), R 4 ~R 6 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, but R 4 ~R 6Two or more of these may be bonded together to form a ring structure.

[0063] R 4 ~R 6 The hydrocarbon group represented by may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aromatic aliphatic hydrocarbon group, or an alicyclic hydrocarbon group. Furthermore, the aliphatic group 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, and aryl groups.

[0064] As the alkyl group, a lower alkyl group having 1 to 6 carbon atoms is preferred, and a lower alkyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, cyclopentyl group, and cyclohexyl group.

[0065] As the alkenyl group, a lower alkenyl group having 1 to 6 carbon atoms is preferred, and a lower alkenyl group having 1 to 4 carbon atoms is more preferred. Examples of such alkenyl groups include vinyl group, n-propenyl group, iso-propenyl group, n-butenyl group, iso-butenyl group, sec-butenyl group, tert-butenyl group, and the like.

[0066] As for the aralkyl group, those with 7 to 12 carbon atoms are preferred. Examples of such aralkyl groups include benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, phenylhexyl group, methylbenzyl group, methylphenethyl group, and ethylbenzyl group.

[0067] The aryl group preferably has 6 to 14 carbon atoms. Examples of such aryl groups 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, an anthryl group, and the like.

[0068] The aromatic rings of the aryl group and the aralkyl group may have, as substituents, for example, lower alkyl groups such as a methyl group and an ethyl group, a halogen atom, a nitro group, an amino group, a hydroxy group, and the like.

[0069] Examples of the carboxy group and its salts include the functional group represented by the following general formula (7). -COO - M + ·····(7) (M + represents a monovalent cation.)

[0070] In the above general formula (7), examples of the monovalent cation represented by M + include, but are not limited to, for example, H + , Li + , Na + , K + , NH4 + .

[0071] 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 an amino group and its salts and at least one functional group selected from the group consisting of a carboxy group and its salts, but preferably has a structure represented by the following general formula (8). -N(CH2COO - M + ) n (R 7 ) 2-n ·····(8) (In the above formula (8), R 7 represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. M + represents a monovalent cation. n represents an integer of 1 to 2.)

[0072] In the above general formula (8), R 7 The hydrocarbon group represented by the above general formulas (6) and (7) is R 4 ~R 6 Examples of hydrocarbon groups similar to those exemplified above include the hydrocarbon group shown above. In the above general formula (8), M + The monovalent cations represented by are not limited to these, but for example, H + Li + kaNa + , K + NH4 + These are some examples.

[0073] Because component (D) has the structure represented by the above general formula (8), component (D) effectively coordinates to and adsorbs onto the ruthenium surface, forming a protective film, thereby suppressing excessive corrosion of the ruthenium portion.

[0074] Examples of component (D) include N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, N-(2-carboxyethyl)iminodiacetic acid, ethylenediaminetetraacetic acid, L-glutamic acid diacetate tetrasodium, glycine-N,N-bis(methylenephosphonic acid), 3,3',3''-nitrilotripropionic acid, glycol etherdiaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 1,3-propanediamine-N,N,N',N'-tetraacetic acid, triethylenetetraaminehexaacetic acid, dihydroxyethylglycine, (S,S)-ethylenediaminedisuccinic acid trihydrate, iminodiacetic acid, and trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid hydrate. These components (D) may be used individually or in combination of two or more.

[0075] The content (mass%) of component (D) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.15% by mass or more, when the total mass of the chemical mechanical polishing composition is considered as 100% by mass. The content (mass%) of component (D) is preferably 5% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less, when the total mass of the chemical mechanical polishing composition is considered as 100% by mass. When the content of component (D) is within the above range, excessive corrosion of semiconductor substrates containing ruthenium can be effectively suppressed.

[0076] 1.5. Other ingredients The chemical mechanical polishing composition according to this embodiment may, in addition to the components described above, optionally 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 salt, a basic compound, and the like.

[0077] <Liquid media> The chemical mechanical polishing composition according to this embodiment contains a liquid medium. Examples of the liquid medium include water, a mixture of water and alcohol, and a mixture containing water and an organic solvent that is compatible with water. Among these, a mixture of water, water and alcohol is preferred, and water is more preferred. Pure water can preferably be used as the raw material for the water. The liquid medium may be included as the remainder of the aforementioned components.

[0078] <Water-soluble polymer> The chemical mechanical polishing composition according to this embodiment may contain a water-soluble polymer. The water-soluble polymer may adsorb to the surface of the surface to be polished, reducing polishing friction and potentially reducing the occurrence of dishing on the polished surface.

[0079] Specific examples of water-soluble polymers include polycarboxylic acids, polystyrene sulfonic acid, polyacrylic acid, polymethacrylic acid, polyethers, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyallylamine, and hydroxyethylcellulose. These can be used individually or in combination of two or more.

[0080] The weight-average molecular weight (Mw) of the water-soluble polymer is preferably 10,000 to 1,500,000, and more preferably 40,000 to 1,200,000. Here, "weight-average molecular weight" refers to the weight-average molecular weight in terms of polyethylene glycol, measured by GPC (gel permeation chromatography).

[0081] 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, and 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, and more preferably 0.01% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass.

[0082] <Nitrogen-containing heterocyclic compounds> Nitrogen-containing heterocyclic compounds are organic compounds comprising at least one heterocyclic ring, selected from heterocyclic five-membered rings and heterocyclic six-membered rings, having at least one nitrogen atom. Specific examples of the heterocyclic ring include heterocyclic five-membered rings such as pyrrole structures, imidazole structures, and triazole structures; and heterocyclic six-membered rings such as pyridine structures, pyrimidine structures, pyridazine structures, and pyrazine structures. The heterocyclic ring may form a fused ring. Specifically, examples include indole structures, isoindole structures, benzimidazole structures, benzotriazole structures, quinoline structures, isoquinoline structures, quinazoline structures, cinnoline structures, phthalazine structures, quinoxaline structures, and acridine structures. Among heterocyclic compounds having such structures, heterocyclic compounds having pyridine structures, quinoline structures, benzimidazole structures, and benzotriazole structures are preferred.

[0083] Specific examples of nitrogen-containing heterocyclic compounds include aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indole, quinoline, isoquinoline, benzoisoquinoline, purine, pteridine, triazole, triazolidine, benzotriazole, carboxybenzotriazole, and derivatives having these skeletons. Among these, it is preferable that at least one is selected from the group consisting of benzotriazole and triazole. These nitrogen-containing heterocyclic compounds may be used individually or in combination of two or more.

[0084] <Surfactants> 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 alkylphenyl ether sulfates; and fluorine-containing surfactants such as perfluoroalkyl compounds. Examples of cationic surfactants include aliphatic amine salts and aliphatic ammonium salts. Examples of nonionic surfactants include nonionic surfactants having triple bonds such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohols; and polyethylene glycol-type surfactants. These surfactants may be used individually or in combination of two or more.

[0085] <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 their salts (excluding component (D)). The organic acid and its salt may, through a synergistic effect with component (A), improve the polishing speed of semiconductor substrates containing ruthenium.

[0086] The organic acids and their salts are preferably compounds having a carboxyl group or a sulfo group. Examples of compounds having a carboxyl group include 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, amidosulfate, propionic acid, trifluoroacetic acid; amino acids such as glycine, alanine, aspartic acid, glutamic acid, lysine, arginine, tryptophan, dodecylaminoethylaminoethylglycine, aromatic amino acids, heterocyclic amino acids, etc.; imino acids such as alkyliminodicarboxylic acids; and salts thereof. Examples of compounds having a sulfo group include alkylbenzene sulfonic acids such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid; alkylnaphthalene sulfonic acids such as butylnaphthalenesulfonic acid; α-olefin sulfonic acids such as tetradecenesulfonic acid; and salts thereof. These compounds may be used individually or in combination of two or more.

[0087] 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, and more preferably 0.01% by 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, and more preferably 1% by mass or less, when the total mass of the chemical mechanical polishing composition is 100% by mass.

[0088] <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 also form a salt with a base added separately in the chemical mechanical polishing composition.

[0089] <Basic compounds> Basic compounds include organic bases and inorganic bases. Preferred organic bases are amines, such as triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine, diglycolamine, and isopropylamine. Examples of inorganic bases include ammonia, potassium hydroxide, and sodium hydroxide. Among these basic compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used individually or in combination of two or more.

[0090] 1.6. pH The pH of the chemical mechanical polishing composition according to this embodiment is preferably 6.0 or higher, more preferably 6.5 or higher, and particularly preferably 7.0 or higher. The pH of the chemical mechanical polishing composition according to this embodiment is preferably 12.0 or lower, more preferably 11.0 or lower, and particularly preferably 10.0 or lower. When the pH is within the above range, the generation of ruthenium tetroxide gas and the corrosion of ruthenium can be effectively suppressed.

[0091] 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.

[0092] In this invention, pH refers to the hydrogen ion concentration, and its value can be measured using a commercially available pH meter (for example, a benchtop pH meter manufactured by Horiba, Ltd.).

[0093] 1.7. Method for preparing chemical mechanical polishing compositions The chemical mechanical polishing composition according to this embodiment can be prepared by dissolving or dispersing the aforementioned components in a liquid medium such as water. The method of dissolution or dispersion is not particularly limited; any method that can achieve uniform dissolution or dispersion may be used. Furthermore, the mixing order and method of the aforementioned components are not particularly limited.

[0094] Furthermore, chemical mechanical polishing compositions can be prepared as concentrated stock solutions and diluted with a liquid medium such as water before use.

[0095] 2. Polishing method A polishing method according to one embodiment of the present invention includes a step of polishing a semiconductor substrate using the chemical mechanical polishing composition described above. The chemical mechanical polishing composition can perform chemical mechanical polishing on a semiconductor substrate containing ruthenium while suppressing ruthenium corrosion and maintaining a stable polishing speed. 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. The polishing method according to this embodiment will be described in detail below with reference to Figures 1 to 4.

[0096] An example of a semiconductor substrate having a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys is the workpiece 100 shown in Figure 1. Figure 1 shows a schematic cross-sectional view of the workpiece 100. The workpiece 100 is manufactured by following the steps (1) to (4) below.

[0097] (1) First, a substrate 10 is prepared as shown in Figure 1. The substrate 10 may consist of, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional devices such as transistors (not shown) may be formed on the substrate 10. Next, a silicon oxide film 12, which is an insulating film, is formed on the substrate 10 using a thermal oxidation method.

[0098] (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.

[0099] (3) Next, a ruthenium-containing film 16 is formed on the surface of the silicon oxide film 12 and on the inner wall surface of the wiring groove 14. The ruthenium-containing film 16 can be formed, for example, by chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a ruthenium precursor, or by physical vapor deposition (PVD) such as sputtering.

[0100] (4) Next, a copper film 18 with a thickness of 10,000 to 15,000 Å (where "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. Preferably, the copper content in the copper-containing alloy is 95% by mass or more.

[0101] Next, the workpiece 100 is subjected to a first polishing step. Figure 2 is a schematic cross-sectional view of the workpiece 100 at the end of the first polishing step. As shown in Figure 2, in the first polishing step, the copper film 18 is polished using a chemical mechanical polishing composition for copper films until the ruthenium-containing film 16 is exposed. An example of a chemical mechanical polishing composition for copper films is the aqueous dispersion for chemical mechanical polishing described in Japanese Patent Application Publication No. 2010-153790.

[0102] Next, a second polishing step is performed on the workpiece 100. Figure 3 is a schematic cross-sectional view of the workpiece 100 at the end of the second polishing step. As shown in Figure 3, in the second polishing step, the ruthenium-containing film 16, the copper film 18, and a portion of the silicon oxide film 12 are polished using the chemical mechanical polishing composition of the present invention.

[0103] For the first and second polishing steps, a polishing apparatus 200, such as the one shown in Figure 4, can be used. Figure 4 is a schematic perspective view of the polishing apparatus 200. The first and second polishing steps are performed by supplying slurry (chemical mechanical polishing composition) 44 from a slurry supply nozzle 42 and rotating a turntable 48 to which a polishing pad 46 is attached, while bringing a carrier head 52 holding a semiconductor substrate 50 into contact with it. A water supply nozzle 54 and a dresser 56 are also shown in Figure 4.

[0104] The material of the polishing pad 46 may be foamed polyurethane, nonwoven fabric, or suede, but foamed polyurethane is preferred.

[0105] The polishing load of the carrier head 52 can be selected within the range of 0.7 to 70 psi, preferably 1.5 to 35 psi. The rotational speed of the turntable 48 and the carrier head 52 can be appropriately selected within the range of 10 to 400 rpm, preferably 30 to 150 rpm. The lower limit of the flow rate of the chemical mechanical polishing composition supplied from the slurry supply nozzle 42 is 15 mL / min, preferably 50 mL / min, and the upper limit of the flow rate is 400 mL / min, preferably 300 mL / min.

[0106] Examples of commercially available polishing equipment include models "EPO-112" and "F-REX300SII" from Ebara Corporation; models "LGP-510" and "LGP-552" from Lappmaster SFT; models "Mirra" and "Reflexion" from Applied Material; model "POLI-400L" from G&P TECHNOLOGY; and model "Reflexion LK" from AMAT.

[0107] 3. Examples The present invention will be described below with reference to examples, but the present invention is not limited in any way by these examples. In these examples, "parts" and "%" are based on mass unless otherwise specified.

[0108] 3.1. Preparation of silica particle aqueous dispersion 3.1.1. Preparation of aqueous dispersion A 2000 g of PL-3 (Fuso Chemical Industries, Ltd., 19.5% colloidal silica dispersion) was mixed with 25% aqueous ammonia (Fujifilm Wako Pure Chemical Industries, Ltd.) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl) mercapto group-containing silane coupling agent (product name "KBM-803", Shin-Etsu Chemical Co., Ltd.) was added dropwise, and the mixture was stirred at 60°C for 2 hours. Subsequently, 50 g of hydrogen peroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was refluxed under atmospheric pressure for 8 hours to obtain an aqueous dispersion A containing cocoon-shaped silica particles surface-modified with sulfo groups, with an average particle size of 58 nm.

[0109] 3.1.2. Preparation of aqueous dispersion B 2000g of PL-3 (manufactured by Fuso Chemical Industries, Ltd., 19.5% colloidal silica dispersion) was heated to 60°C. Then, 15.5g of (3-triethoxysilyl)propyl succinic anhydride (manufactured by Tokyo Chemical Industries, Ltd.) was added, and the mixture was stirred at 60°C for 4 hours to obtain aqueous dispersion B containing cocoon-shaped silica particles with an average particle size of 60nm, surface-modified with carboxyl groups.

[0110] 3.1.3. Preparation of aqueous dispersion C A mixture of 70 g of methanol and 11.3 g of 3-aminopropyltriethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise to 2000 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion), and refluxed under atmospheric pressure for 2 hours. Then, pure water was added dropwise while maintaining a constant volume, and the addition of pure water was stopped when the column top temperature reached 100°C, yielding an aqueous dispersion C containing cocoon-shaped silica particles surface-modified with amino groups, with an average particle size of 56 nm.

[0111] 3.1.4. Preparation of aqueous dispersion D 1950 g of PL-2L (Fuso Chemical Industries, Ltd., 20% colloidal silica dispersion) was mixed with 25% aqueous ammonia (Fujifilm Wako Pure Chemical Industries, Ltd.) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl) mercapto group-containing silane coupling agent (product name "KBM-803", Shin-Etsu Chemical Co., Ltd.) was added dropwise, and the mixture was stirred at 60°C for 2 hours. Subsequently, 50 g of hydrogen peroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was refluxed under atmospheric pressure for 8 hours to obtain an aqueous dispersion D containing spherical silica particles surface-modified with sulfo groups, with an average particle size of 23 nm.

[0112] 3.1.5. Preparation of aqueous dispersion E PL-3 (manufactured by Fuso Chemical Industries, Ltd., 19.5% colloidal silica dispersion) was used as is as aqueous dispersion E containing unmodified silica particles with an average particle size of 60 nm.

[0113] 3.2. Preparation of chemical mechanical polishing compositions Each component was mixed to obtain the composition shown in Tables 1 to 3. Potassium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Ltd., trade name "48% potassium hydroxide aqueous solution") and phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "phosphate") were added as needed to adjust the pH to the levels shown in Tables 1 to 3. Pure water was then added to bring the total amount of all components to 100% by mass, thereby preparing the chemical mechanical polishing compositions for each example and comparative example. The zeta potential of the abrasive grains was measured for each chemical mechanical polishing composition obtained in this way using a zeta potential measuring device (manufactured by Dispersion Technology Inc., model "DT300"), and the results are shown in Tables 1 to 3.

[0114] 3.3. Evaluation Method 3.3.1. Polishing Speed ​​Evaluation Using the chemical mechanical polishing composition prepared above, a 12-inch diameter wafer with a 100 nm ruthenium film was used as the workpiece for a chemical mechanical polishing test under the following conditions. (polishing conditions) • Polishing machine: Ebara Corporation, model "F-REX300SII" • Polishing pad: DuPont, "Porous polyurethane pad; Optivision 9500 CMP Polishing pad" ·Chemical mechanical polishing composition supply rate: 250mL / min • Plate rotation speed: 100 rpm • Head rotation speed: 90 rpm • Head pressure: 2 psi ·Polishing time: 60 seconds Polishing speed (nm / min) = (Thickness of film before polishing (nm) - Thickness of film after polishing (nm)) / Polishing time (min)

[0115] The thickness of the ruthenium film was calculated using the following formula based on the sheet resistance value and the volume resistivity of ruthenium, measured using the DC four-probe method with a resistivity meter (KLA-Tencor, model "RS-100"). Ruthenium film thickness (nm) = [Volume resistivity of ruthenium film (Ω·m) ÷ Sheet resistance (Ω / sq)] × 10 9

[0116] The evaluation criteria for the polishing speed of the ruthenium film are as follows. The evaluation results for the polishing speed of the ruthenium film are shown in Tables 1 to 3. (Evaluation Criteria) A: If the polishing speed is 1000 nm / min or higher, it is considered very good. B: When the polishing speed is between 50 nm / min and less than 1000 nm / min, it is deemed acceptable as it can be used in practice. C: If the polishing speed is less than 50 nm / min, it is judged to be defective because the polishing speed is too low and impractical.

[0117] 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 in it for 5 minutes. After that, the wafer piece was removed and washed with running water, and the thickness of the ruthenium film was measured using the same method as in "3.3.1. Polishing Speed ​​Evaluation" above. The etching rate was then 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)

[0118] The evaluation criteria for the etching rate of ruthenium films are as follows. The evaluation results for the etching rate of ruthenium films are shown in Tables 1 to 3. (Evaluation Criteria) A: We considered an etching rate of less than 1.5 nm / min to be very good. B: If the etching rate is between 1.5 nm / min and less than 3 nm / min, it is considered acceptable as it can be used in practice. C: If the etching rate is 3 nm / min or higher, it is judged to be defective because the etching rate is too high and impractical.

[0119] 3.3.3. Storage Stability Assessment The chemical mechanical polishing compositions prepared above were stored in a constant temperature storage chamber at 20°C for 3 or 7 days. Then, a chemical mechanical polishing test was performed on a 12-inch diameter wafer with a 100 nm ruthenium film attached, using the same polishing conditions as in "3.3.1. Polishing Speed ​​Evaluation" above. The rate of change in the polishing speed of the ruthenium film before and after storage was calculated using the following formula. Variation rate (%) = |((Polishing speed calculated in section 3.3.1. Polishing speed evaluation) - (Polishing speed when using chemical mechanical polishing composition after storage)) / (Polishing speed calculated in section 3.3.1. Polishing speed evaluation) × 100|

[0120] The evaluation criteria for the rate of change are as follows. The evaluation results for the storage stability of chemical mechanical polishing compositions are shown in Tables 1 to 3. (Evaluation Criteria) A: If the rate of change in polishing speed after 7 days of storage is less than 10%, it is considered to be very good. B: If the rate of change in polishing speed after 3 days of storage is less than 10%, but the rate of change in polishing speed after 7 days of storage is 10% or more, it is judged to be good as it can be used for practical purposes. C: If the rate of change in polishing speed after 3 days of storage is 10% or more, it is judged to be unsuitable for practical use.

[0121] 3.4. Evaluation Results Tables 1 to 3 show the composition of the chemical mechanical polishing compositions used in each example and comparative example, as well as the evaluation results.

[0122] [Table 1]

[0123] [Table 2]

[0124] [Table 3]

[0125] Each component in Tables 1 to 3 above was obtained using the following products or reagents. <Ingredient (A)> • Aqueous dispersions A-E: Aqueous dispersions A-E prepared in the section "3.1. Preparation of silica particle aqueous dispersions" above. <Ingredient (B)> • H5IO6 (periodic acid): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Orthoperiodic acid" • KClO (potassium hypochlorite): Manufactured by Kanto Chemical Co., 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: 30% aqueous solution, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. <Ingredient (D)> • N-(phosphonomethyl)iminodiacetic acid: Manufactured by Sigma-Aldrich, trade name "N-(phosphonomethyl)iminodiacetic acid hydrate" • Hydroxyethyliminodiacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N-(2-Hydroxyethyl)iminodiacetic Acid" • N-(2-carboxyethyl)iminodiacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N-(2-Carboxyethyl)iminodiacetic Acid" • Nitrilotriacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Nitrilotriacetic Acid" • 3,3',3''-Nitrilotripionic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "3,3',3''-Nitrilopropionic Acid" • Ethylenediaminetetraacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Ethylenediaminetetraacetic Acid" • Tetrasodium L-glutamate diacetate: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Tetrasodium N,N-Bis(carboxymethyl)-L-glutamate (ca. 40% in Water)" Glycine-N,N-bis(methylenephosphonic acid): Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Glycine-N,N-bis(methylenephosphonic Acid)" • Glycol etherdiaminetetraacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Ethylene Glycol Bis(2-aminoethyl Ether)-N,N,N',N'-tetraacetic Acid" • Hydroxyethylethylenediaminetriacetic acid: Manufactured by 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, Ltd., product name "Potassium Iodate" • (NH4)2S2O8 (Ammonium peroxodisulfate): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Ammonium peroxodisulfate"

[0126] According to the chemical mechanical polishing compositions of Examples 1 to 18, which fall within the MB / MC range of 0.015 to 11, component (B) can oxidize ruthenium to improve the polishing speed of the ruthenium film, and component (C) reacts with ruthenium to prevent excessive reaction between ruthenium and specific anionic species contained in component (B), thereby suppressing corrosion of the ruthenium film.

[0127] In contrast, with the chemical mechanical polishing compositions of Comparative Examples 1 and 2, which contain compounds that do not contain specific anion species, it is found that the polishing speed of the ruthenium film is reduced because ruthenium cannot be effectively oxidized. With the chemical mechanical polishing compositions of Comparative Examples 3 and 5, where MB / MC is greater than 11, it is found that the content of component (B) is too high relative to the content of component (C), and the excess amount of component (B) induces corrosion of the ruthenium film. With the chemical mechanical polishing composition of Comparative Example 4, where MB / MC is less than 0.015, it is found that the content of component (B) is too low relative to the content of component (C), and ruthenium cannot be effectively oxidized, resulting in a reduced polishing speed of the ruthenium film.

[0128] The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially identical to the configurations described in the embodiments (for example, configurations with the same function, method and result, 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. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as the configurations described in the embodiments. Furthermore, the present invention includes configurations that add known technology to the configurations described in the embodiments. [Explanation of symbols]

[0129] 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…Workpiece, 200…Polishing device

Claims

1. Abrasive grain (A) and Periodate ion (IO ４ － ), hypochlorite ion (ClO － ), chlorite ion (ClO ２ － ) and hypobromite ions (BrO － An acid or a salt thereof (B) containing at least one anion selected from the group consisting of ), It contains hydrogen peroxide (C) and When the content of the acid or its salt (B) is MB (mol / L) and the content of the hydrogen peroxide (C) is MC (mol / L), then MB / MC = 0.015 to 11. The pH is between 7 and 12. A chemical mechanical polishing composition for polishing a semiconductor substrate having a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys.

2. The chemical mechanical polishing composition according to claim 1, wherein the abrasive grain (A) has a functional group represented by the following general formula (1) or (2). -SO ３ － M ＋ ・・・・・(1) -COO － M ＋ ・・・・・(2) (M ＋ (This represents a monovalent cation.)

3. The chemical mechanical polishing composition according to claim 1, wherein the abrasive grain (A) has a functional group represented by the following general formula (3) or (4). -NR １ R ２ ・・・・・・(3) -N ＋ R １ R ２ R ３ M － ・・・・・(4) (In the above equations (3) and (4), R １ , R ２ and R ３ Each of these independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － (This represents an anion.)

4. The chemical mechanical polishing composition according to any one of claims 1 to 3, wherein the absolute value of the zeta potential of the abrasive grain (A) in the chemical mechanical polishing composition is 10 mV or more.

5. Claims 1 to 1, wherein the MB (mol / L) is 0.001 to 0.05 mol / L. A chemical mechanical polishing composition as described in any one of item 4.

6. A polishing method comprising the step of polishing a semiconductor substrate having a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys, using a chemical mechanical polishing composition according to any one of claims 1 to 5.

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