TW202326838A - Composition for chemical mechanical polishing and polishing method - Google Patents

Abstract

The present invention provides a composition for chemical mechanical polishing, the composition being capable of chemically mechanically polishing a semiconductor substrate that contains ruthenium, while maintaining a stable polishing rate and suppressing corrosion of ruthenium. A composition for chemical mechanical polishing according to the present invention contains (A) abrasive grains, (B) an acid containing at least one kind of anion that is selected from the group consisting of a periodate ion (IO4 -), a hypochlorite ion (ClO-), a chlorite ion (ClO2 -) and a hypobromite ion (BrO-), or a salt thereof, and a liquid medium; if MA (% by mass) is the content of the abrasive grains (A) and MB (% by mass) is the content of the acid or a salt thereof (B), MA/MB is 0.2 to 50; and the absolute value of the zeta potential of the abrasive grains (A) in this composition for chemical mechanical polishing is 10 mV or more.

Description

Composition for chemical mechanical polishing and polishing method

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

Along with the improvement of the manufacturing technology of semiconductor integrated circuits, high-integration and high-speed operation of semiconductor elements are required. Along with this, the flatness of the surface of the semiconductor substrate required in the manufacturing process of the fine circuit in the semiconductor device has become stricter, and chemical mechanical polishing (CMP) has become an indispensable technology in the manufacturing process of the semiconductor device .

CMP is a technique of supplying a composition for chemical mechanical polishing to a polishing pad attached to a table, pressing the semiconductor substrate against the polishing pad, and sliding the semiconductor substrate and the polishing pad against each other, thereby polishing the semiconductor substrate. Grinding is performed chemically and mechanically. In CMP, the roughness on the surface of the semiconductor substrate can be ground to planarize the surface by chemical reaction of reagents and mechanical polishing with abrasive grains.

In recent years, methods using a ruthenium film have been studied in order to improve the embedment of copper into recesses when forming copper wiring of a semiconductor substrate produced by such CMP (for example, refer to Patent Document 1 to Patent Document 3). [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2009-514219 [Patent Document 2] Japanese Patent Application Publication No. 2010-535424 [Patent Document 3] International Publication No. 2019/151145

[Problem to be Solved by the Invention] 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 use an alkaline chemical mechanical polishing composition, potassium periodate or potassium hypochlorite with high The oxidizing power of the halogen-based oxidizing agent is used for chemical mechanical polishing. However, if an alkaline chemical mechanical polishing composition is used, the generation of ruthenium tetroxide gas can be suppressed, but insufficiently oxidized ruthenium oxide adheres to the surface of the polishing pad, deteriorating the polishing properties of the polishing pad. As a result, it is difficult to chemically mechanically polish 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 possibility of corrosion of ruthenium.

Several aspects of the present invention provide a composition for chemical mechanical polishing that suppresses corrosion of ruthenium and performs chemical mechanical polishing on a semiconductor substrate containing ruthenium while maintaining a stable polishing rate. [Means to solve the problem]

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

One ^aspect of _{the composition} for chemical mechanical ^polishing of ^the present invention includes: abrasive grains (A); ) and hypobromite ion (BrO ^- ) at least one anion acid or its salt (B); and a liquid medium, when the content of the abrasive grain (A) is set as MA (mass %), when the content of the acid or its salt (B) is defined as MB (mass %), MA/MB=0.2 to 50, the abrasive grains (A ) The absolute value of the zeta potential is above 10 mV.

In one form of the composition for chemical mechanical polishing, The MA (mass %) may be 0.01 mass % to 10 mass %.

In any form of the composition for chemical mechanical polishing, The MB (mass %) may be 0.01 mass % to 10 mass %.

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

A form of the grinding method of the present invention includes: A step of polishing a semiconductor substrate using any one of the chemical mechanical polishing compositions described above.

In one form of the grinding method, The semiconductor substrate may include a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys. [Effect of the invention]

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

Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, Various modification examples implemented in the range which does not change the summary of this invention are included.

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

1. Chemical Mechanical Polishing Composition A chemical mechanical polishing composition according to an embodiment of the present invention contains: abrasive grains (A) (also referred to as "component (A)" in this specification); (IO ₄ ^- ), hypochlorite ion (ClO ^- ), chlorite ion (ClO ₂ ^- ) and hypobromite ion (BrO ^- ) at least one anion acid or its salt (B ) (also referred to as "ingredient (B)" in this specification); and a liquid medium, and in the composition for chemical mechanical polishing, when the content of the abrasive grain (A) is MA (mass %) , when the content of the acid or its salt (B) is taken as MB (mass %), MA/MB=0.2 to 50, and the abrasive grain (A) in the chemical mechanical polishing composition The absolute value of the zeta potential is above 10 mV. Hereinafter, each component contained in the chemical mechanical polishing composition of the present embodiment will be described in detail.

1.1. Composition (A) The chemical mechanical polishing composition of the present embodiment contains abrasive grains (A). Examples of the component (A) include 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. From the viewpoint of reducing polishing defects such as scratches, colloidal silica is preferably used. As colloidal silica, colloidal silica produced by the method described in Unexamined-Japanese-Patent No. 2003-109921 etc. can be used, for example.

When the component (A) is silica particles having silica as a main component, the component (A) may further contain other components. Examples of other components include aluminum compounds, silicon compounds, and the like. Since the silica particles further contain aluminum compounds or silicon compounds, the surface hardness of the silica particles can be reduced. Therefore, it is possible to further reduce the occurrence of grinding damage or dents on the polished surface while maintaining a stable grinding speed. Condition.

Examples of the aluminum compound include aluminum hydroxide, aluminum oxide (alumina), aluminum chloride, aluminum nitride, aluminum acetate, aluminum phosphate, aluminum sulfate, sodium aluminate, potassium aluminate, and the like. On the other hand, examples of the silicon compound include silicon nitride, silicon carbide, silicate, silicone, and silicone resin.

The shape of the component (A) is not particularly limited, and may be spherical, cocoon-like, interlocking spherical, or may have a plurality of protrusions on the surface. Abrasive grains having a plurality of protrusions on the surface can be produced by applying, for example, the method described in JP-A-2007-153732 or JP-A-2013-121631.

The absolute value of the zeta potential of the component (A) is 10 mV or more, preferably 15 mV or more, more preferably 20 mV or more in the chemical mechanical polishing composition. If the absolute value of the zeta potential of the component (A) is within the above range, the aggregation of the particles can be effectively prevented by the electrostatic repulsion force between the abrasive particles, and the semiconductor substrate containing ruthenium can be polished at a more stable polishing rate. grind. In addition, examples of the zeta potential measuring device include "ELSZ-2000ZS" manufactured by Otsuka Electronics Co., Ltd., "Zetasizer Ultra" manufactured by Malvern Corporation, and Dispersion Technology Inc. ( "DT300" manufactured by Dispersion Technology Inc., etc.

When the total mass of the chemical mechanical polishing composition is 100% by mass, the content [MA (mass %)] of the component (A) is preferably at least 0.1% by mass, more preferably at least 0.3% by mass, and most preferably at least 0.5% by mass. Mass% or more. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content [MA (mass %)] of the component (A) is preferably at most 10% by mass, more preferably at most 8% by mass, most preferably at most 5% by mass. Mass% or less. When the content of the component (A) is within the above range, the semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may become good.

Component (A) is preferably an abrasive grain in which at least a part of its surface is modified with a functional group. Abrasive grains whose surface is at least partly modified with functional groups have a larger absolute value of zeta potential and an increased electrostatic repulsion between abrasive grains than abrasive grains whose surface is not modified with functional groups. As a result, since the dispersibility of the abrasive grains in the chemical mechanical polishing composition improves, high-speed polishing can be performed while reducing the occurrence of polishing damage and dishing.

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

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

The component (A) having a functional group represented by the general formula (1) can be produced as follows. First, the mercapto-containing silane coupling agent can be covalently bonded to the surface of the silica by fully stirring the silicon dioxide and the mercapto-containing silane coupling agent prepared by a known method in an acidic medium. Here, examples of the mercapto group-containing silane coupling agent include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Next, by further adding an appropriate amount of hydrogen peroxide and leaving it to stand sufficiently, the component (A) having the functional group represented by the general formula (1) can be obtained.

The zeta potential of the component (A) having the functional group represented by the general formula (1) is a negative potential in the composition for chemical mechanical polishing, and the negative potential is preferably -10 mV or less, more preferably -15 mV. Below mV, preferably below -20 mV. If the zeta potential of the component (A) is in the above range, the electrostatic repulsion between the abrasive particles can effectively prevent the aggregation of the particles, and the semiconductor substrate containing ruthenium can be polished at a more stable polishing rate. Condition. In addition, the above-mentioned device can be used for the zeta potential measuring device. The zeta potential of the component (A) can be adjusted by appropriately increasing or decreasing the added amount of the mercapto-containing silane coupling agent or the like.

In the case where the chemical mechanical polishing composition of the present embodiment contains the component (A) having a functional group represented by the general formula (1), when the total mass of the chemical mechanical polishing composition is taken as 100% by mass , the content of the component (A) (mass %) is preferably at least 0.5 mass %, more preferably at least 1 mass %. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content (% by mass) of the component (A) is preferably at most 10% by mass, more preferably at most 5% by mass. If the content of the component (A) having the functional group represented by the general formula (1) is within the above range, the semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the composition for chemical mechanical polishing can be polished. When preservation stability becomes good.

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

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

The component (A) having a functional group represented by the general formula (2) can be produced as follows. First, fully stir the silicon dioxide and the silane coupling agent containing carboxylic anhydride in an alkaline medium, so that the silane coupling agent containing carboxylic anhydride is covalently bonded to the surface of the abrasive grains, thereby obtaining Abrasive grains having a functional group represented by the general formula (2). Here, as a silane coupling agent containing a carboxylic acid anhydride, 3-(triethoxysilyl) propyl succinic anhydride etc. are mentioned, for example.

The zeta potential of the component (A) having the functional group represented by the general formula (2) is a negative potential in the composition for chemical mechanical polishing, and the negative potential is preferably -10 mV or less, more preferably -15 mV. Below mV, preferably below -20 mV. If the zeta potential of the component (A) is in the above range, the electrostatic repulsion between the abrasive particles can effectively prevent the aggregation of the particles, and the semiconductor substrate containing ruthenium can be polished at a more stable polishing rate. Condition. In addition, the above-mentioned device can be used for the zeta potential measuring device. The zeta potential of the component (A) having the functional group represented by the general formula (2) can be adjusted by appropriately increasing or decreasing the added amount of the carboxylic anhydride-containing silane coupling agent or the like.

In the case where the chemical mechanical polishing composition of the present embodiment contains the component (A) represented by the general formula (2), when the total mass of the chemical mechanical polishing composition is taken as 100% by mass, the component ( The content of A) is preferably at least 0.1% by mass, more preferably at least 0.3% by mass, and most preferably at least 0.5% by mass. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the component (A) is preferably at most 10% by mass, more preferably at most 8% by mass, and most preferably at most 5% by mass. When the content of the component (A) is within the above range, the semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may become good.

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 the above formula (3) and the above formula (4), R ¹ , R ² and R ³ each independently represent a hydrogen atom, or a substituted or unsubstituted hydrocarbon group. M ^- represents an anion).

The functional group represented by the general formula (3) represents an amine group, and the functional group represented by the general formula (4) represents a salt of an amine group. Therefore, the functional groups represented by the general formula (3) and the functional groups represented by the general formula (4) can also be collectively referred to as "selected from the group consisting of amine groups and their salts". at least one functional group". The component (A) having the functional group represented by the general formula (3) and/or the general formula (4) has the general formula (3) and/or the Abrasive grains with functional groups represented by the general formula (4), and do not contain the functional groups represented by the general formula (3) and/or the general formula (4) on their surface physically or ionically adsorbed Abrasive grains of compounds.

In the general formula (4), the anion represented by M ^- is not limited to these, for example, in addition to anions such as OH ^- , F ^- , Cl ^- , Br ^- , I ^- , CN ^-, etc., there may also be mentioned Anions derived from acidic compounds.

In the general formula (3) and the general formula (4), R ¹ to R ³ each independently represent a hydrogen atom, or a substituted or unsubstituted hydrocarbon group, but two or more of R ¹ to R ³ It can also be bonded to form a ring structure.

The hydrocarbon groups represented by R ¹ to R ³ may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, or an alicyclic hydrocarbon group. In addition, the aliphatic group of 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.

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

The alkenyl group is usually preferably a lower alkenyl group having 1 to 6 carbon atoms, more preferably a lower alkenyl group having 1 to 4 carbon atoms. As such an alkenyl group, a vinyl group, n-propenyl group, isopropenyl group, n-butenyl group, isobutenyl group, second butenyl group, third butenyl group etc. are mentioned, for example.

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

Usually, 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, anthracenyl, etc.

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

The component (A) having the functional group represented by the general formula (3) and/or the general formula (4) is, for example, fully stirred with the silane coupling agent containing an amino group in an acidic medium, Abrasive grains having the functional groups represented by the general formula (3) and/or the general formula (4) can be produced by covalently bonding the amino group-containing silane coupling agent to the surface of the silica. Here, examples of the amino group-containing silane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and the like.

The zetaelectricity of the component (A) having the functional group represented by the general formula (3) and/or the general formula (4) has a negative potential in the composition for chemical mechanical polishing, and the negative potential is preferably Below -10 mV, more preferably below -15 mV. If the zeta potential of the component (A) is in the above range, the electrostatic repulsion between the abrasive particles can effectively prevent the aggregation of the particles, and the semiconductor substrate containing ruthenium can be polished at a more stable polishing rate. Condition. In addition, the above-mentioned device can be used for the zeta potential measuring device. The zeta potential of the component (A) having the functional group represented by the general formula (3) and/or the general formula (4) can be adjusted by appropriately increasing or decreasing the addition of the amine-containing silane coupling agent, etc. amount to adjust.

In the case where the composition for chemical mechanical polishing of this embodiment contains the component (A) having the functional group represented by the general formula (3) and/or the general formula (4), when the composition for chemical mechanical polishing When the total mass of the composition is 100% by mass, the content of the component (A) is preferably at least 0.1% by mass, more preferably at least 0.5% by mass, and most preferably at least 1% by mass. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content of the component (A) is preferably at most 10% by mass, more preferably at most 8% by mass, and most preferably at most 5% by mass. When the content of the component (A) is within the above range, the semiconductor substrate containing ruthenium can be polished at a stable polishing rate, and the storage stability of the chemical mechanical polishing composition may become good.

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

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

The content (mol/L) of the component (B) is preferably at least 0.001 mol/L, more preferably at least 0.002 mol/L, and most preferably at least 0.003 mol/L relative to 1 L of the chemical mechanical polishing composition. The content (mol/L) of the component (B) is preferably at most 0.05 mol/L, more preferably at most 0.04 mol/L, particularly preferably at most 0.035 mol/L, relative to 1 L of the chemical mechanical polishing composition. When the content of the component (B) is within the above-mentioned range, ruthenium may be oxidized to promote polishing, and excessive reaction of ruthenium and specific anion species may be prevented to suppress ruthenium corrosion.

When the total mass of the chemical mechanical polishing composition is 100% by mass, the content [MB (% by mass)] of the component (B) is preferably at least 0.01% by mass, more preferably at least 0.05% by mass, particularly preferably at least 0.01% by mass. 0.1% by mass or more. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content [MB (% by mass)] of the component (B) is preferably at most 10% by mass, more preferably at most 8% by mass, particularly preferably at most 7% by mass or less. When the content of the component (B) is within the above-mentioned range, ruthenium may be oxidized to promote polishing, and excessive reaction of ruthenium and specific anion species may be prevented to suppress ruthenium corrosion.

When MA (mass %) is the content of the abrasive grain (A) and MB (mass %) is the content of the acid or its salt (B), the value of MA/MB is preferably 0.2 or more. , more preferably at least 0.25, particularly preferably at least 0.3. The value of MA/MB is preferably at most 50, more preferably at most 40, particularly preferably at most 30. When the value of MA/MB is in the above range, the corrosion of ruthenium can be suppressed, the polishing of ruthenium can be promoted, and the storage stability of the composition for chemical mechanical polishing can be improved.

1.3. Composition (C) The chemical mechanical polishing composition of the present embodiment may contain hydrogen peroxide (C) (also referred to as "component (C)" in this specification). Hydrogen peroxide (C) has the following functions: to oxidize ruthenium to promote grinding, and to prevent excessive reaction of ruthenium and specific anion species contained in component (B) by reacting component (C) with ruthenium, thereby suppressing halogen gas generation or corrosion of ruthenium.

The content (mol/L) of the component (C) is preferably at least 0.0005 mol/L, more preferably at least 0.0009 mol/L, and most preferably at least 0.0012 mol/L relative to 1 L of the chemical mechanical polishing composition. The content (mol/L) of the component (C) is preferably at most 0.5 mol/L, more preferably at most 0.4 mol/L, particularly preferably at most 0.3 mol/L, relative to 1 L of the chemical mechanical polishing composition. If the content of component (C) is in the above range, ruthenium can be oxidized to promote grinding, and by reacting component (C) with ruthenium, excessive reaction of ruthenium and specific anion species contained in component (B) can be prevented. , Inhibit the corrosion of ruthenium.

When the total mass of the chemical mechanical polishing composition is 100% by mass, the content (% by mass) of the component (C) is preferably at least 0.0017% by mass, more preferably at least 0.003% by mass, most preferably at least 0.004% by mass above. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content (% by mass) of the component (C) is preferably at most 1.7% by mass, more preferably at most 1.4% by mass, most preferably at most 1% by mass the following. If the content of component (C) is in the above range, ruthenium can be oxidized to promote grinding, and by reacting component (C) with ruthenium, excessive reaction of ruthenium and specific anion species contained in component (B) can be prevented. , Inhibit the corrosion of ruthenium.

1.4. Composition (D) The chemical mechanical polishing composition of this embodiment may contain at least one functional group selected from the group consisting of amine groups and their salts, and at least one functional group selected from the group consisting of carboxyl groups and their salts. Compound (D) (also referred to as "ingredient (D)" in this specification).

Examples of the amine group and its salt include functional groups represented by the following general formula (5) or the following general formula (6). -NR ⁴ R ⁵ R ⁶ R ⁷・・・・・(5) -N ^＋ R ⁴ R ⁵ R ⁶ M ^-・・・・・(6) (The above formula (5) and the above formula (6) In, R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, or a substituted or unsubstituted hydrocarbon group. M ^- represents an anion.)

In the general formula (5) and the general formula (6), R ⁴ to R ⁷ each independently represent a hydrogen atom, or a substituted or unsubstituted hydrocarbon group, and two or more of R ⁴ to R ⁷ may be bonds to form a ring structure.

The hydrocarbon group represented by R ⁴ to R ⁷ may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, or an alicyclic hydrocarbon group. In addition, the aliphatic group of 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.

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

The alkenyl group is usually preferably a lower alkenyl group having 1 to 6 carbon atoms, more preferably a lower alkenyl group having 1 to 4 carbon atoms. As such an alkenyl group, a vinyl group, a n-propenyl group, an isopropenyl group, a n-butenyl group, an isobutenyl group, a 2-butenyl group, a 3-butenyl group etc. are mentioned, for example.

The aralkyl group is usually preferably one having 7 to 12 carbon atoms. As such an aralkyl group, a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a phenylhexyl group, a methylbenzyl group, a methylphenethyl group, an ethylbenzyl group etc. are mentioned, for example.

Usually, 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, anthracenyl, etc.

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

As a carboxyl group and its salt, the functional group represented by following General formula (7) is mentioned. -COO ^- M ⁺・・・・・（7） (M ⁺ represents a monovalent cation.)

In the general formula (7), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

As long as component (D) has a structure having at least one functional group selected from the group consisting of amine groups and their salts, and at least one functional group selected from the group consisting of carboxyl groups and their salts, there is no It is particularly limited, but preferably has a structure represented by the following general formula (8). -N(CH ₂ COO ^- M ⁺ ) _n (R ⁸ ) _n-3・・・・・・(8) (In the formula (8), R ⁸ represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. M ⁺ represents a monovalent cation. n represents an integer of 1 to 3.)

In the general formula (8), examples of the hydrocarbon group represented by R ⁸ include the same hydrocarbon groups as those exemplified for R ⁴ to R ⁷ in the general formula (6) and the general formula (7). In the general formula (8), the monovalent cation represented by M ⁺ is not limited to these, and examples thereof include H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ .

By making component (D) have the structure represented by the said general formula (8), component (D) is effectively coordinated and adsorb|sucked on the surface of ruthenium, and forms a protective film, thereby suppressing the excessive corrosion of a ruthenium part.

Component (D) includes, for example, N-(phosphonomethyl)iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, N-(2-carboxyethyl)imine Diacetic acid, ethylenediaminetetraacetic acid, tetrasodium L-glutamine diacetate, glycine-N,N-bis(methylenephosphonic acid), 3,3',3''-nitrotripropyl acid, glycol ether diaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 1,3-propanediamine-N,N,N',N'-tetraacetic acid, triethylenetetraaminehexaacetic acid, di Hydroxyethylglycine, (S,S)-ethylenediaminedisuccinic 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.

When the total mass of the chemical mechanical polishing composition is 100% by mass, the content (% by mass) of the component (D) is preferably at least 0.05% by mass, more preferably at least 0.1% by mass, and most preferably at least 0.15% by mass. above. When the total mass of the chemical mechanical polishing composition is 100% by mass, the content (% by mass) of the component (D) is preferably at most 5% by mass, more preferably at most 2% by mass, most preferably at most 1% by mass the following. When the content of the component (D) is within the above range, excessive corrosion of the semiconductor substrate containing ruthenium can be effectively suppressed.

1.5. Other ingredients The composition for chemical mechanical polishing according to this embodiment may contain a liquid medium, a water-soluble polymer, a nitrogen-containing heterocyclic compound, a surfactant, an organic acid and its salt, an inorganic acid, and Its salts, basic compounds, etc.

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

＜Water-soluble polymer＞ The chemical mechanical polishing composition of this embodiment may also contain a water-soluble polymer. Water-soluble polymers may be adsorbed on the surface of the surface to be polished to reduce polishing friction, thereby reducing the occurrence of dents on the surface to be polished.

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

The weight average molecular weight (Mw) of the water-soluble polymer is preferably from 10,000 to 1.5 million, more preferably from 40,000 to 1.2 million. Here, the "weight average molecular weight" refers to the weight average molecular weight in terms of polyethylene glycol measured by gel permeation chromatography (Gel Permeation Chromatography, GPC).

In the case where the chemical mechanical polishing composition of the present embodiment contains a water-soluble polymer, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%, the content of the water-soluble polymer is preferably 0.001 mass % or more, 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 at most 0.1% by mass, more preferably at most 0.01% by mass.

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

Specific examples of nitrogen-containing heterocyclic compounds include aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indole, quinoline, isoquinoline, and benzisoquinone. Phine, 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 preferable. These nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

＜Surfactant＞ The surfactant is not particularly limited, and anionic surfactants, cationic surfactants, nonionic surfactants, and the like can be used. Examples of the anionic surfactant include: sulfates such as alkyl ether sulfates and polyoxyethylene alkylphenyl ether sulfates; fluorine-containing surfactants such as perfluoroalkyl compounds; and the like. As a cationic surfactant, an aliphatic amine salt, an aliphatic ammonium salt, etc. are mentioned, for example. Examples of the nonionic surfactant include nonionic surfactants having triple bonds such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohol; polyethylene glycol-type surfactants; and the like. These surfactants may be used alone or in combination of two or more.

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

As organic acids and salts thereof, compounds having a carboxyl group and compounds having a sulfo group are preferable. Examples of compounds having a carboxyl group include stearic acid, lauric acid, oleic acid, myristic acid, alkenylsuccinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, formic acid , acetic acid, oxalic acid, citric acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinolinic acid, quinaldinic acid, amidosulfuric acid, propionic acid, trifluoroacetic acid; glycine, propylamine Acid, aspartic acid, glutamic acid, lysine, arginine, tryptophan, dodecylaminoethylaminoethylglycine, aromatic amino acid, heterocyclic amino amino acid such as acid; imino acid such as alkyliminodicarboxylic acid; and their salts. Examples of compounds having a sulfo group include alkylbenzenesulfonic acids such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid; alkylnaphthalenesulfonic acids such as butylnaphthalenesulfonic acid; and α-olefins such as tetradecenesulfonic acid. Sulfonic acids; and their salts. These compounds may be used alone or in combination of two or more.

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

＜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. Furthermore, the inorganic acid may form a salt with a base additionally added to the chemical mechanical polishing composition.

＜Basic compounds＞ Examples of the basic compound include organic bases and inorganic bases. The organic base is preferably an amine, for example, triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine Amine, diglycolamine, isopropylamine, etc. As an inorganic base, ammonia, potassium hydroxide, sodium hydroxide etc. are mentioned, for example. Among these basic compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used alone or in combination of two or more.

1.6.pH The pH of the composition for chemical mechanical polishing according to the present embodiment is preferably at least 6.0, more preferably at least 6.5, and most preferably at least 7.0. The pH of the chemical mechanical polishing composition of the present 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 or the corrosion of ruthenium may be effectively suppressed.

Furthermore, the pH of the composition for chemical mechanical polishing can be adjusted by adding the above-mentioned organic acid (salt), inorganic acid (salt), basic compound, etc., and one or more of them can be used.

In the present invention, pH refers to a hydrogen ion index, and its value can be measured using a commercially available pH meter (eg, table-top pH meter manufactured by Horiba, Ltd.).

1.7. Preparation method of composition for chemical mechanical polishing The chemical mechanical polishing composition of the present embodiment can be prepared by dissolving or dispersing the above components in a liquid medium such as water. The method of dissolution or dispersion is not particularly limited, and any method can be applied as long as it can be dissolved or dispersed uniformly. In addition, there is no particular limitation on the mixing order and mixing method of the above-mentioned components.

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

2. Grinding method A polishing method according to one embodiment of the present invention includes the step of polishing a semiconductor substrate using the composition for chemical mechanical polishing. The composition for chemical mechanical polishing suppresses corrosion of ruthenium and performs chemical mechanical polishing on a semiconductor substrate containing ruthenium while maintaining a stable polishing rate. Therefore, it is preferable that the semiconductor substrate to be processed includes a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys. Hereinafter, the polishing method of this embodiment will be described in detail with reference to FIGS. 1 to 4 .

As a semiconductor substrate including a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys, for example, an object to be processed 100 as shown in FIG. 1 is exemplified. FIG. 1 shows a schematic cross-sectional view of an object 100 to be processed. The object to be processed 100 is produced through the following steps (1) to (4).

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

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

(3) Next, the 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 grown, for example, by chemical vapor deposition (Chemical Vapor Deposition, CVD) or atomic layer deposition (Atomic Layer Deposition, ALD) using a ruthenium precursor, or physical vapor deposition (Physical Vapor Deposition) such as sputtering. Vapor Deposition, PVD) to form.

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

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

Next, the second grinding step of the object to be processed 100 is performed. FIG. 3 is a cross-sectional view schematically showing the object 100 at the end of the second polishing step. As shown in FIG. 3, in the second polishing step, a part of the ruthenium-containing film 16, the copper film 18, and the silicon oxide film 12 is polished using the composition for chemical mechanical polishing of the present invention.

In the first grinding step and the second grinding step, for example, a grinding device 200 as shown in FIG. 4 can be used. FIG. 4 is a perspective view schematically showing the polishing device 200 . The first polishing step and the second polishing step are to supply the slurry (chemical mechanical polishing composition) 44 from the slurry supply nozzle 42, and rotate the turntable 48 to which the polishing pad 46 is attached, while holding the The semiconductor substrate 50 is brought into contact with a carrier head 52 . In addition, FIG. 4 also shows the water supply nozzle 54 and the dresser (dresser) 56 together.

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

The grinding load of the carrier head 52 can be selected within the range of 0.7 psi-70 psi, preferably 1.5 psi-35 psi. In addition, the rotation speed of the turntable 48 and the carrier head 52 can be appropriately selected within the range of 10 rpm to 400 rpm, preferably 30 rpm to 150 rpm. The lower limit of the flow rate of the composition for chemical mechanical polishing 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. mL/min.

Examples of commercially available polishing devices include models "EPO-112" and "F-REX300SII" manufactured by Ebara Seisakusho, and models "LGP-510" and "LGP-552" manufactured by Lapmaster SFT. ; models "Mirra" and "Reflexion" manufactured by Applied Material; models "POLI-400L" manufactured by G&P Technology (TECHNOLOGY); models "Reflexion" manufactured by AMAT Reflexion) LK", etc.

3. Example Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited by these examples. In addition, "part" and "%" in this Example are mass basis unless otherwise indicated.

3.1. Preparation of aqueous dispersion of silica particles 3.1.1. Preparation of aqueous dispersion A 25% ammonia water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 2000 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical 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, Ltd.) was added, and refluxed at normal pressure for 8 hours to obtain cocoon-shaped silica particles having an average particle diameter of 58 nm and surface-modified with sulfo groups. Aqueous dispersion A.

3.1.2. Preparation of aqueous dispersion B 2000 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion) was heated to 60°C. Then, 15.5 g of (3-triethoxysilyl)propyl succinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirred at 60° C. for 4 hours to obtain a carboxyl group-modified particle with an average particle diameter of 60 nm. Aqueous dispersion B of cocoon-shaped silica particles.

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 PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion) 2000 g, under normal pressure for 2 hours reflux. Then, pure water was added dropwise while keeping the volume constant, and the drop of pure water was stopped when the temperature at the top of the tower reached 100°C to obtain cocoon-shaped carbon dioxide containing an average particle size of 56 nm and surface-modified with amine groups. Aqueous dispersion of silicon particles C.

3.1.4. Preparation of aqueous dispersion D 25% ammonia water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to 1950 g of PL-2L (manufactured by Fuso Chemical Industry Co., Ltd., 20% colloidal silica dispersion) to adjust the pH to 9. Then, 3.9 g of a (3-triethoxysilyl)mercapto group-containing silane coupling agent (trade name "KBM-803", manufactured by Shin-Etsu Chemical 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, Ltd.) was added and refluxed at normal pressure for 8 hours to obtain water containing spherical silica particles surface-modified with sulfo groups with an average particle diameter of 23 nm. dispersion D.

3.1.5. Preparation of aqueous dispersion E PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., 19.5% colloidal silica dispersion liquid) was used as it is for aqueous dispersion E containing non-surface-modified silica particles with an average particle diameter of 60 nm.

3.2. Preparation of composition for chemical mechanical polishing Each component was mixed so that the composition shown in Tables 1 to 3 was obtained, and an aqueous potassium hydroxide solution (manufactured by Kanto Chemical Co., Ltd., trade name "48% Hydrogen Potassium oxide aqueous solution") and phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "phosphoric acid"), pure water was added so that the total amount of all components became 100% by mass, and each example and each comparative example were prepared. Composition for chemical mechanical polishing. For each composition for chemical mechanical polishing obtained in the above 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 measurement results were They are shown in Table 1 to Table 3 together.

3.3. Evaluation method 3.3.1. Grinding speed evaluation Using the composition for chemical mechanical polishing prepared above, a wafer with a diameter of 12 inches and a 100 nm ruthenium film was used as the object to be polished, and the chemical mechanical polishing test was carried out under the following conditions. (grinding condition) ・Grinding device: Ebara Seisakusho Co., Ltd., model "F-REX300SII" ・Polishing pad: "Porous polyurethane pad; Optivision 9500 CMP polishing pad" manufactured by Dupont ・Chemical mechanical polishing composition supply rate: 250 mL/min ・Platen speed: 100 rpm ・Grinding head speed: 90 rpm ・Press pressure of grinding head: 2 psi ・Grinding time: 60 seconds ・Polishing speed (nm/min) = (film thickness before polishing (nm) - film thickness after polishing (nm))/polishing time (minutes)

Furthermore, the thickness of the ruthenium film is measured by a resistivity measuring machine (manufactured by KLA-Tencor, model "RS-100") by the DC 4-probe method. and the volume resistivity of ruthenium were calculated from the following formula. Thickness of ruthenium film (nm) = [volume resistivity of ruthenium film (Ω･m) ÷ sheet resistance value (Ω/sq)] × 10 ⁹

The evaluation criteria of the polishing rate of the ruthenium film are as follows. The evaluation results of the polishing rate of the ruthenium film are collectively shown in Tables 1 to 3. (evaluation criteria) A: When the polishing rate is 1000 nm/min or more, it is judged to be very good. B: When the polishing rate is 50 nm/minute or more and less than 1000 nm/minute, it can be used practically, so it was judged as good. C: When the polishing rate is less than 50 nm/min, the polishing rate is too small to be practical, so it was judged as defective.

3.3.2. Etching rate evaluation The chemical mechanical polishing composition prepared above was heated to 60° C., and a wafer cut into 30 mm×10 mm with a 100 nm ruthenium film was immersed for 5 minutes. Then, the wafer was taken out, washed with running water, and the thickness of the ruthenium film was measured by the same method as in the above-mentioned "3.3.1. Polishing rate evaluation". Then, from the change in the thickness of the ruthenium film before and after immersion, the etching rate was calculated by 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 (minutes)

The evaluation criteria of the etching rate of the ruthenium film are as follows. The evaluation results of the etching rate of the ruthenium film are collectively shown in Tables 1 to 3. (evaluation criteria) A: When the etching rate is less than 1.5 nm/min, it is judged to be very good. B: When the etching rate is not less than 1.5 nm/min and less than 3 nm/min, it can be used for practical use, so it was judged to be good. C: When the etching rate is 3 nm/min or more, the etching rate is too high to be practical, so it was judged as defective.

3.3.3. Storage stability evaluation After storing the composition for chemical mechanical polishing prepared above in a constant temperature storage room at 20° C. for 3 days or 7 days, a wafer with a diameter of 12 inches and a 100 nm ruthenium film was used as the object to be polished. A chemical mechanical polishing test was performed under the same polishing conditions as described in "3.3.1. Evaluation of polishing speed". Then, the variation rate of the polishing rate of the ruthenium film before and after storage was calculated by the following formula. Variation rate (%)=|((Polishing rate calculated in item "3.3.1. Grinding speed calculated in "Grinding speed evaluation" item) × 100|

The evaluation criteria of the rate of change are as follows. The evaluation results of the storage stability of the chemical mechanical polishing composition are collectively shown in Tables 1 to 3. (evaluation criteria) A: When the fluctuation rate of the polishing rate after 7 days of storage is less than 10%, it is judged to be very good. B: The variation rate of the polishing rate after 3 days of storage is less than 10%, but the rate of variation of the polishing rate after 7 days of storage is 10% or more, so it can be used for practical use, so it is judged as good. C: When the variation rate of the polishing rate after 3 days of storage was 10% or more, it was judged as defective because it was difficult to put into practical use.

3.4. Evaluation Results Tables 1 to 3 show the composition of the chemical mechanical polishing composition used in each of the Examples and each of the Comparative Examples and each of the evaluation results.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Composition for Chemical Mechanical Polishing Abrasive grains (A) type Water dispersion A Water dispersion A Water dispersion A Water dispersion A water dispersion D Water dispersion B Water dispersion B water dispersion C Water dispersion A Types of functional groups Sulfur Sulfur Sulfur Sulfur Sulfur carboxyl carboxyl Amino Sulfur Zeta potential (mV) -38 -38 -38 -38 -40 -twenty three -twenty three -10 -38 Average particle size (nm) 58 58 58 58 twenty three 60 60 56 58 Content MA (mass%) 0.1 0.1 2.5 0.5 5.0 2.0 3.0 3.0 0.1 Acids or their salts containing specific anionic species (B) type H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ specific anion species IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- Content MB (mass%) 0.3 0.3 0.3 0.4 0.1 0.3 0.4 0.3 0.2 Hydrogen peroxide (C) Content (mol/L) 0.0036 0.0036 0.0904 0.0181 0.2794 0.0029 0.0044 0.0044 0.0036 Compound (D) type N-(phosphonomethyl)iminodiacetic acid N-(phosphonomethyl)iminodiacetic acid hydroxyethyliminodiacetic acid hydroxyethyliminodiacetic acid hydroxyethyliminodiacetic acid N-(phosphonomethyl)iminodiacetic acid hydroxyethyliminodiacetic acid hydroxyethyliminodiacetic acid N-(2-carboxyethyl)iminodiacetic acid Content (mass%) 0.2 0.8 0.15 0.15 0.15 0.2 0.2 0.2 0.15 other ingredients type Content (mass%) MA (mass %)/MB (mass %) 0.33 0.33 8.3 1.3 50.0 6.7 7.5 10.0 0.5 pH 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.0 Evaluation results Ru grinding speed evaluation A A A A A A A B A Ru etching rate evaluation A A A A A A A A B Storage Stability Evaluation A B B B B A A A A

[Table 2] Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Composition for Chemical Mechanical Polishing Abrasive grains (A) type Water dispersion B water dispersion C water dispersion D Water dispersion E Water dispersion E Water dispersion E Water dispersion A Water dispersion A Water dispersion A Types of functional groups carboxyl Amino Sulfur - - - Sulfur Sulfur Sulfur Zeta potential (mV) -19 -16 -45 -35 -30 -38 -38 -38 -38 Average particle size (nm) 60 56 twenty three 60 60 60 58 58 58 Content MA (mass%) 0.8 0.6 0.2 2.0 2.0 2.0 0.1 0.1 0.1 Acids or their salts containing specific anionic species (B) type H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ KClO _KClO2 NaBrO specific anion species IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^- IO ₄ ^{- ClO-} ClO ₂ ^{- BrO-} Content MB (mass%) 0.1 0.2 0.1 0.1 0.2 0.1 0.3 0.3 0.3 Hydrogen peroxide (C) Content (mol/L) 0.0012 0.0009 0.0112 0.0029 0.0029 0.0029 0.0036 0.0036 0.0036 Compound (D) type Nitrilotriacetic acid 3,3',3''-Nitrotripropionic acid Ethylenediaminetetraacetic acid Tetrasodium L-glutamate diacetate Glycine-N,N-bis(methylenephosphonic acid) Glycol ether diamine tetraacetic acid N-(phosphonomethyl)iminodiacetic acid N-(phosphonomethyl)iminodiacetic acid N-(phosphonomethyl)iminodiacetic acid Content (mass%) 0.16 0.175 0.25 0.295 0.225 0.32 0.2 0.2 0.2 other ingredients type Content (mass%) MA (mass%)/MB (mass%) 8.0 3.0 2.0 20.0 10.0 20.0 0.33 0.33 0.33 pH 6.0 9.0 8.0 11.0 10.0 12.0 7.5 7.5 7.5 Evaluation results Ru grinding speed evaluation A B A B B B A A A Ru etching rate evaluation B B B B B B A A A Storage Stability Evaluation A A B B B B A A A

[table 3] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative Example 5 Composition for Chemical Mechanical Polishing Abrasive grains (A) type Water dispersion A Water dispersion A Water dispersion A Water dispersion E Water dispersion A Types of functional groups Sulfur Sulfur Sulfur - Sulfur Zeta potential (mV) -38 -38 -38 -8 -38 Average particle size (nm) 58 58 58 58 58 Content MA (mass%) 0.1 0.1 2.5 0.1 2.0 Acids or their salts containing specific anionic species (B) type - - H ₅ IO ₆ H ₅ IO ₆ H ₅ IO ₆ specific anion species - - IO ₄ ^- IO ₄ ^- IO ₄ ^- Content MB (mass%) - - 0.03 1.0 0.03 Hydrogen peroxide (C) Content (mol/L) 0.0036 0.0036 0.0904 0.0001 0.0724 Compound (D) type Hydroxyethylethylenediaminetriacetic acid Hydroxyethylethylenediaminetriacetic acid hydroxyethyliminodiacetic acid N-(phosphonomethyl)iminodiacetic acid hydroxyethyliminodiacetic acid Content (mass%) 0.235 0.235 0.15 0.2 0.15 other ingredients type KIO ₃ (NH ₄ ) ₂ S ₂ O ₈ Content (mass%) 0.2 0.2 MA (mass %)/MB (mass %) - - 83.3 0.1 66.7 pH 7.5 7.5 7.5 4.0 7.5 Evaluation results Ru grinding speed evaluation C C C A C Ru etching rate evaluation B B A C A Storage Stability Evaluation A A C C C

The following products or reagents were used for each component in the above Tables 1 to 3, respectively. <Component (A)> ・Water dispersion A to water dispersion E: Water dispersion A to water dispersion E prepared in the section "3.1. Preparation of aqueous silica particle dispersion" above <Component (B) ＞ ・H ₅ IO ₆ (periodic acid): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "orthoperiodic acid" ・KClO (potassium hypochlorite): manufactured by Kanto Chemical Co., Ltd., trade name "potassium hypochlorite solution" ・KClO ₂ (Potassium chlorite): manufactured by Angene Corporation, trade name "Potassium Chlorite" ・NaBrO (sodium hypobromite): manufactured by Kanto Chemical Co., Ltd., trade name "sodium hypobromite"<Component (C) ＞ ・Hydrogen peroxide: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 30% aqueous solution <Component (D)> ・N-(phosphonomethyl)iminodiacetic acid: Sigma-Aldrich Manufactured, 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-Hydroxyethyl)iminodiacetic Acid)” ・N-(2-carboxyethyl)iminodiacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name “N-(2-carboxyethyl) ) iminodiacetic acid (N-(2-Carboxyethyl)iminodiacetic Acid)" ・Nitrilotriacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Nitrilotriacetic Acid"・3,3',3" -Nitrilopropionic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "3,3',3"-Nitrilopropionic Acid (3,3',3"-Nitrilopropionic Acid) ・Ethylenediaminetetraacetic acid: Tokyo Manufactured by Kasei Kogyo Co., Ltd., trade name "Ethylenediaminetetraacetic Acid" ・Tetrasodium L-glutamine diacetate: Manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name "N,N-bis(carboxymethyl)-L -Tetrasodium N,N-Bis(carboxymethyl)-L-glutamate (ca. 40% in Water (about 40% aqueous solution))" ・Glycine-N,N-bis(methylene Phosphonic acid): manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Glycine-N,N-bis(methylenephosphonic acid) (Glycine-N,N-bis(methylenephosphonic acid))" ・Glycol ether diamine tetra Acetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Ethylene Glycol Bis(2-aminoethyl Ether)-N,N,N',N'-tetraacetic acid (Ethylene Glycol Bis(2-aminoethyl Ether)-N, N,N',N'-tetraacetic Acid)" ・Hydroxyethylethylenediaminetriacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "N-(2-hydroxyethyl)ethylenediamine-N,N',N '-Triacetic acid (N-(2-Hydroxyethyl)ethylenediamine-N,N',N'-triacetic Acid)"<Otheringredients> ・KIO ₃ (potassium iodate): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name " Potassium iodate" ・(NH ₄ ) ₂ S ₂ O ₈ (ammonium peroxodisulfate): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "ammonium peroxodisulfate"

According to the compositions for chemical mechanical polishing in Examples 1 to 18, it can be seen that component (B) can oxidize ruthenium, increase the polishing speed of ruthenium film, and prevent ruthenium from interacting with specific anion species contained in component (B). The overreaction of the ruthenium film is inhibited. In addition, it was found that the storage stability was improved by setting the absolute value of the zeta potential of the component (A) contained in the chemical mechanical polishing compositions of Examples 1 to 18 to be 10 mV or more.

On the other hand, according to the chemical mechanical polishing compositions of Comparative Examples 1 to 2 containing the compound not containing the specific anion species, the polishing rate of the ruthenium film was reduced because the ruthenium could not be oxidized effectively. From the chemical mechanical polishing compositions of Comparative Example 3 and Comparative Example 5 in which MA/MB exceeds 50, it can be seen that ruthenium cannot be oxidized effectively because the content of component (A) is too large relative to the content of component (B). , the grinding speed of the ruthenium film becomes smaller. According to the composition for chemical mechanical polishing of Comparative Example 4 whose MA/MB is less than 0.2, it can be seen that since the content of component (A) is too small relative to the content of component (B), excessive component (B) induces cracking of the ruthenium film. Corrosion, since the absolute value of the zeta potential of the component (A) is less than 10 mV, the storage stability is not significantly impaired.

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes structures substantially the same as those described in the embodiments (for example, structures having the same functions, methods, and results, or structures having the same purpose and effects). In addition, this invention includes the structure which replaced the non-essential part of the structure demonstrated in embodiment. In addition, the present invention includes configurations that exhibit the same effects as the configurations described in the embodiments, or configurations that can achieve the same purpose. In addition, the present invention includes structures obtained by adding known techniques to the structures described in the embodiments.

10: Matrix 12: Silicon oxide film 14: Groove for wiring 16: Membrane containing ruthenium 18: copper film 42: Slurry supply nozzle 44: Slurry (composition for chemical mechanical polishing) 46: Grinding pad 48: turntable 50:Semiconductor substrate 52: carrier head 54: Water supply nozzle 56: Dresser 100: object to be processed 200: grinding device

FIG. 1 is a schematic cross-sectional view of an object to be processed that is suitable for use in the polishing step of the present embodiment. Fig. 2 is a cross-sectional view schematically showing the object to be processed at the end of the first polishing step. Fig. 3 is a cross-sectional view schematically showing the object to be processed at the end of the second polishing step. Fig. 4 is a perspective view schematically showing a chemical mechanical polishing device.

Claims (7)

A composition for chemical mechanical polishing, comprising: abrasive particles (A); consisting of periodate ion IO ₄ ^- , hypochlorite ion ClO ^- , chlorite ion ClO ₂ ^- and hypobromite ion BrO ^- The acid or its salt (B) of at least one anion in the group; and the liquid medium, when the content of the abrasive grain (A) is set as MA mass %, the acid or its salt (B) When the content is MB mass %, MA/MB=0.2 to 50, and the absolute value of the zeta potential of the abrasive grains (A) in the chemical mechanical polishing composition is 10 mV or more. The composition for chemical mechanical polishing according to claim 1, wherein the mass % of MA is 0.01 mass % to 10 mass %. The composition for chemical mechanical polishing according to claim 1 or claim 2, wherein the MB mass % is 0.01 mass % to 10 mass %. The composition for chemical mechanical polishing according to claim 1 or claim 2, wherein the pH is 6 or more and 12 or less. The composition for chemical mechanical polishing according to claim 3, wherein the pH is 6 or more and 12 or less. A polishing method, comprising the step of polishing a semiconductor substrate using the composition for chemical mechanical polishing according to any one of claim 1 to claim 5. The polishing method according to claim 6, wherein the semiconductor substrate includes a portion composed of at least one selected from the group consisting of ruthenium and ruthenium alloys.