Method for producing abrasive grains, chemical mechanical polishing composition, and polishing method

Abstract

To provide: a chemical mechanical polishing composition capable of rapidly polishing a silicon oxide film while suppressing the occurrence of polishing defects during polishing of the silicon oxide film, and also exhibiting excellent polishing characteristics even after storage; a polishing method using the same; and a method for producing abrasive grains that can be used in the chemical mechanical polishing composition.SOLUTION: The chemical mechanical polishing composition according to the present invention contains abrasive grains and a liquid medium. Polymer chains are grafted onto the surface of the abrasive grains through covalent bonding, and the abrasive grains have, on their surface, at least one type of partial structure selected from the group consisting of the partial structure represented by the following general formula (3) and the partial structure represented by the following general formula (4): -NR2R3 (3); and -N+R2R3R4M- (4) (In the formulas (3) and (4), R2, R3 and R4 each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group, and M- represents an anion.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing abrasive grains, a chemical mechanical polishing composition, and a polishing method. [Background technology]

[0002] With the advancement of semiconductor integrated circuit manufacturing technology, there is a demand for higher integration and faster operation of semiconductor elements. Accordingly, the flatness of the semiconductor substrate surface required in the manufacturing process of fine circuits in semiconductor elements is becoming increasingly strict, and chemical mechanical polishing (hereinafter also referred to as "CMP") has become an essential technology in the manufacturing process of semiconductor elements.

[0003] CMP is utilized, for example, in the planarization of interlayer insulating films in the process of forming multilayer wiring, the formation of metal plugs, and the formation of buried wiring (damascene wiring). In order to achieve well-balanced polishing properties in these processes, various polishing compositions (slurries) have been proposed (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-235652 [Patent Document 2] International Publication No. 2017-057155 Summary of the Invention [Problem to be solved by the invention]

[0005] In the chemical mechanical polishing composition described above, in order to improve the yield of semiconductor device manufacturing processes, it is required to improve the polishing rate of silicon oxide films and suppress the occurrence of polishing defects during polishing of silicon oxide films. Furthermore, when silica is used as abrasive grains in the chemical mechanical polishing composition described above, the abrasive grains tend to aggregate over time during storage of the chemical mechanical polishing composition, generating coarse particles, which tends to impair the polishing properties of the chemical mechanical polishing composition after storage. For example, the aggregation of abrasive grains during storage of the chemical mechanical polishing composition tends to decrease the polishing rate of silicon oxide films and increase polishing scratches after polishing of the silicon oxide films.

[0006] Some aspects of the present invention provide a chemical mechanical polishing composition that can polish silicon oxide films at high speed, can suppress the occurrence of polishing defects during polishing of silicon oxide films, and has excellent polishing properties after storage, as well as a polishing method using the same.

[0007] Furthermore, some aspects of the present invention provide a method for producing abrasive grains that can be used in the above-described chemical mechanical polishing composition. [Means for solving the problem]

[0008] One aspect of the method for producing abrasive grains according to the present invention is to A step (a) of heating a mixture containing particles having hydroxyl groups (—OH) immobilized on the surface thereof via covalent bonds and an alkoxysilane (A) having an epoxy group; After the step (a), a step (b) of adding a basic compound and heating; After the step (b), a step (c) of adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture; Includes:

[0009] One aspect of the method for producing abrasive grains according to the present invention is to a step (d) of heating a mixture containing particles having hydroxyl groups (—OH) immobilized on the surface thereof via covalent bonds and an alkoxysilane (B) having an amino group; After the step (d), a step (e) of adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture; Includes:

[0010] In any one of the above-described methods for producing abrasive grains, The particles may be silica particles.

[0011] In any one of the above-described methods for producing abrasive grains, The polyalkylene oxide chain of the alkoxysilane (C) may have at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2): -(CH2CH2O)- (1) -(CHR 1 CH2O)- (2) (In the formula, R 1 is C m H 2m+1 where m is an integer of 1 to 4.

[0012] In any one of the above-described methods for producing abrasive grains, The basic compound may be at least one selected from the group consisting of ammonia and compounds having an amino group.

[0013] In any one of the above-described methods for producing abrasive grains, The abrasive grains may have, on their surfaces, at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4). -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0014] In any one of the above-described methods for producing abrasive grains, The abrasive grains may have a partial structure represented by the following general formula (5) on the surface thereof. [ka] (In formula (5), R 5 represents a single bond or a divalent organic group having one or more carbon atoms, and R 6 represents a divalent organic group having one or more carbon atoms, and R 7 , R 8 and R 9 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0015] In any one of the above-described methods for producing abrasive grains, The abrasive grains may have a partial structure represented by the following general formula (6) on the surface thereof. [ka] (In formula (6), R 10 represents a divalent organic group having one or more carbon atoms, and R 11 and R 12 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0016] In any one of the above-described methods for producing abrasive grains, In the chemical mechanical polishing composition containing the abrasive grains, the abrasive grains may have a zeta potential of 0 mV or more.

[0017] One aspect of the chemical mechanical polishing composition of the present invention is abrasive grains produced by the method of any of the above aspects; A liquid medium; Contains:

[0018] One aspect of the chemical mechanical polishing composition of the present invention is A chemical mechanical polishing composition comprising an abrasive grain and a liquid medium, a polymer chain is grafted to the surface of the abrasive grain by a covalent bond; The abrasive grains have, on their surfaces, at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4). -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0019] In any one of the embodiments of the chemical mechanical polishing composition, The polymer chains covalently grafted to the surface of the abrasive grains may be polyalkylene oxide chains.

[0020] In any one of the embodiments of the chemical mechanical polishing composition, The polyalkylene oxide chain grafted to the surface of the abrasive grain by a covalent bond may have at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2): -(CH2CH2O)- (1) -(CHR 1 CH2O)- (2) (In the formula, R 1 is C m H 2m+1 where m is an integer of 1 to 4.

[0021] In any one of the embodiments of the chemical mechanical polishing composition, The abrasive grains may have a partial structure represented by the following general formula (5) on the surface thereof. [ka] (In formula (5), R 5 represents a single bond or a divalent organic group having one or more carbon atoms, and R 6 represents a divalent organic group having one or more carbon atoms, and R 7 , R 8 and R 9 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0022] In any one of the embodiments of the chemical mechanical polishing composition, The abrasive grains may have a partial structure represented by the following general formula (2) on the surface thereof. [ka] (In formula (6), R 10 represents a divalent organic group having one or more carbon atoms, and R 11 and R 12 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0023] In any one of the embodiments of the chemical mechanical polishing composition, The pH may be 2 or more and 6 or less.

[0024] Any embodiment of the chemical mechanical polishing composition may further comprise: It may be one used for polishing silicon oxide films.

[0025] One aspect of the polishing method according to the present invention is to The method includes a step of polishing a silicon oxide film using the chemical mechanical polishing composition of any one of the above embodiments. [Effects of the Invention]

[0026] The chemical mechanical polishing composition of the present invention can polish silicon oxide films at high speeds and suppress the occurrence of polishing defects during polishing of silicon oxide films. Furthermore, when the chemical mechanical polishing composition of the present invention is stored, it exhibits excellent storage stability and maintains excellent polishing properties after storage. Furthermore, the method for producing abrasive grains of the present invention can produce abrasive grains that can polish silicon oxide films at high speeds and suppress the occurrence of polishing defects during polishing of silicon oxide films, as well as maintain excellent polishing properties after storage of the chemical mechanical polishing composition. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a perspective view schematically showing a polishing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0028] Preferred embodiments of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and various embodiments may be implemented within the scope of the present invention. This also includes variations of the above.

[0029] In this specification, "(meth)acrylic acid" refers to "acrylic acid" or "methacrylic acid." Similarly, "(meth)acrylamide" refers to "acrylamide" or "methacrylamide."

[0030] In this specification, a range of values ​​described using "X to Y" is interpreted as including the value X as the lower limit and the value Y as the upper limit.

[0031] 1. Manufacturing method of abrasive grains The method for producing abrasive grains according to a first embodiment of the present invention includes the steps of: (a) heating a mixture containing particles having hydroxyl groups (—OH) covalently fixed to their surfaces and an alkoxysilane (A) having an epoxy group; (b) adding a basic compound and heating the mixture after the step (a); and (c) adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture after the step (b). The method for producing abrasive grains according to the first embodiment can polish silicon oxide films at high speed, suppress the occurrence of polishing defects during polishing of silicon oxide films, and produce abrasive grains that have excellent polishing properties even after storage of the chemical mechanical polishing composition.

[0032] In the method for producing abrasive grains according to the first embodiment, particles having hydroxyl groups (-OH) fixed to their surfaces via covalent bonds are mixed with an alkoxysilane (A) having an epoxy group and a basic compound, followed by heating to obtain abrasive grains having at least one partial structure selected from the group consisting of the partial structure represented by the following general formula (3) and the partial structure represented by the following general formula (4). Furthermore, by adding an alkoxysilane (C) having a polyalkylene oxide chain and heating, abrasive grains having a polyalkylene oxide chain further introduced as a graft chain on their surfaces can be obtained. The mixing method is not particularly limited, but by performing steps (a), (b), and (c), side reactions of the components can be suppressed.

[0033] The method for producing abrasive grains according to a second embodiment of the present invention includes the steps of: (d) heating a mixture containing particles having hydroxyl groups (—OH) covalently fixed to their surfaces and an alkoxysilane (B) having an amino group; and (e) adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture after the step (d). The method for producing abrasive grains according to the second embodiment can polish silicon oxide films at high speed, suppress the occurrence of polishing defects during polishing of silicon oxide films, and produce abrasive grains that have excellent polishing properties even after storage of the chemical mechanical polishing composition.

[0034] In the second embodiment of the method for producing abrasive grains, particles having hydroxyl groups (-OH) fixed to their surfaces via covalent bonds are mixed with an alkoxysilane (B) having an amino group and heated to obtain abrasive grains having at least one partial structure selected from the group consisting of the partial structure represented by the following general formula (3) and the partial structure represented by the following general formula (4). Furthermore, by adding an alkoxysilane (C) having a polyalkylene oxide chain and heating, abrasive grains having a polyalkylene oxide chain further introduced as a graft chain on their surfaces can be obtained. The mixing method is not particularly limited, but by performing steps (d) and (e), side reactions of the components can be suppressed.

[0035] -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0036] Hereinafter, each step of the method for manufacturing abrasive grains according to each embodiment will be described.

[0037] 1.1. First embodiment 1.1.1. Process (a) Step (a) is a step of heating a mixture containing particles having hydroxyl groups (-OH) immobilized on the surface via covalent bonds and an alkoxysilane (A) having an epoxy group. By undergoing step (a), it is possible to produce particles having organic groups having epoxy groups immobilized on the surface of the particles.

[0038] The heating temperature in step (a) can be between room temperature and 100° C., and preferably between 40° C. and 80° C. The heating time can be between 10 minutes and 24 hours, and preferably between 30 minutes and 12 hours.

[0039] In step (a), particles having hydroxyl groups (-OH) immobilized on the surface via covalent bonds are used. Such particles having hydroxyl groups (-OH) immobilized on the surface via covalent bonds do not include particles having compounds having hydroxyl groups physically or ionically adsorbed on the surface.

[0040] The material of the particles having hydroxyl groups (-OH) fixed to the surface via covalent bonds, which are the raw material of the abrasive grains, is not particularly limited, and examples thereof include inorganic oxides such as silica, ceria, alumina, zirconia, and titania. Among these, silica is preferred. Examples of silica include fumed silica and colloidal silica, with colloidal silica being preferred from the viewpoint of reducing polishing defects such as scratches. Colloidal silica has hydroxyl groups on the surface, such as Si-OH, and can be produced by the method described in, for example, JP 2003-109921 A.

[0041] In step (a), an alkoxysilane (A) having an epoxy group is used to immobilize an organic group having an epoxy group on the particle surface. The alkoxysilane (A) having an epoxy group is not particularly limited as long as it is a compound in which the alkoxy group is hydrolyzed to generate a silanol group, which can undergo a dehydration condensation reaction with the hydroxyl group (-OH) immobilized on the particle surface to bond to the particle surface. By reacting with the alkoxysilane (A) having an epoxy group, an organic group having an epoxy group can be easily immobilized on the particle surface.

[0042] As the alkoxysilane (A) having an epoxy group, an alkoxysilane having two or three alkoxy groups bonded to a silicon atom can be preferably used. As the alkoxy group, a lower alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group is preferred, with a methoxy group or an ethoxy group being more preferred. Furthermore, as the epoxy group, a glycidyloxyalkyl group is preferred, with a glycidyloxypropyl group being more preferred.

[0043] Specific examples of the alkoxysilane (A) having an epoxy group include glycidyloxyalkyltrialkoxysilane, glycidyloxyalkyldialkoxysilane, and 2-(3,4-epoxycyclohexyl)alkyltrialkoxysilane. Examples of the glycidyloxyalkyltrialkoxysilane include 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane. Examples of the glycidyloxyalkyldialkoxysilane include 3-glycidyloxypropyl(methyl)dimethoxysilane and 3-glycidyloxypropyl(methyl)diethoxysilane. Examples of the 2-(3,4-epoxycyclohexyl)alkyltrialkoxysilane include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. Among these, 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane are particularly preferred. Iethoxysilane is more preferred. These alkoxysilanes (A) having an epoxy group may be used alone or in combination of two or more.

[0044] 1.1.2. Process (b) Step (b) is a step of further adding a basic compound to the particles obtained in step (a) on whose surface an organic group having an epoxy group is immobilized via a covalent bond, and heating the particles. By adding an appropriate amount of a basic compound to the particles obtained in step (a) on whose surface an organic group having an epoxy group is immobilized via a covalent bond, and heating the particles, the epoxy group immobilized on the surface and the basic compound undergo a ring-opening reaction, thereby forming at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4): -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0045] The partial structure represented by the general formula (3) above represents an amino group, and the partial structure represented by the general formula (4) represents a salt of an amino group. Therefore, the partial structure represented by the general formula (3) and the partial structure represented by the general formula (4) can be collectively referred to as "at least one functional group selected from the group consisting of amino groups and salts thereof." In this specification, "abrasive grains having on their surface at least one partial structure selected from the group consisting of the partial structure represented by the following general formula (3) and the partial structure represented by the following general formula (4)" refers to abrasive grains having on their surface the partial structures represented by the general formula (3) and / or the general formula (4) fixed via covalent bonds, but does not include a grain having on its surface a compound having the partial structure represented by the general formula (3) and / or the general formula (4) physically or ionically adsorbed.

[0046] In the above formula (3) and the above formula (4), R 2 ~R4 each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, 2 ~R 4 Two or more of these may be bonded to form a ring structure.

[0047] R 2 ~R 4 The hydrocarbon group represented by the formula (I) may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an araliphatic hydrocarbon group, or an alicyclic hydrocarbon group. The aliphatic group in the aliphatic hydrocarbon group and the araliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. Examples of these hydrocarbon groups include linear, branched, and cyclic alkyl groups, alkenyl groups, aralkyl groups, and aryl groups.

[0048] The alkyl group is preferably a lower alkyl group having 1 to 6 carbon atoms, and more preferably a lower alkyl group having 1 to 4 carbon atoms. Examples of such alkyl groups include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a cyclopentyl group, and a cyclohexyl group.

[0049] The alkenyl group is preferably a lower alkenyl group having 1 to 6 carbon atoms, and more preferably a lower alkenyl group having 1 to 4 carbon atoms. Examples of such alkenyl groups include a vinyl group, an n-propenyl group, an iso-propenyl group, an n-butenyl group, an iso-butenyl group, a sec-butenyl group, and a tert-butenyl group.

[0050] The aralkyl group preferably has 7 to 12 carbon atoms. Examples of such groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylhexyl, methylbenzyl, methylphenethyl, and ethylbenzyl groups.

[0051] The aryl group preferably has a carbon number of 6 to 14. Examples of such an aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, an p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,5-xylyl group, a naphthyl group, and an anthryl group.

[0052] The aromatic rings of the aralkyl and aryl groups may have, as substituents, lower alkyl groups such as methyl and ethyl groups, halogen atoms, nitro groups, amino groups, hydroxy groups, and the like.

[0053] In the above formula (4), M - Examples of anions represented by the formula (I) include, but are not limited to, OH - , F - , Cl - , Br - , I - , C.N. - In addition to anions such as those mentioned above, anions derived from acidic compounds can also be mentioned.

[0054] In the step (b), the partial structure formed on the surface of the particle is preferably a partial structure represented by the following general formula (5) or a partial structure represented by the following general formula (6). [ka] (In formula (5), R 5 represents a single bond or a divalent organic group having one or more carbon atoms, and R 6 represents a divalent organic group having one or more carbon atoms, and R 7 , R 8 and R 9 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0055] R 5 When R is a divalent organic group having one or more carbon atoms, 5 is -(CH2) nIt preferably has a structure represented by O- (n is an integer of 1 or more).

[0056] R 6 The divalent organic group having one or more carbon atoms represented by R may be any of a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, a divalent araliphatic hydrocarbon group, and a divalent alicyclic hydrocarbon group, and may be linear or branched. 6 is -(CH2) n It is preferable that the compound has a structure represented by - (n is an integer of 1 or more).

[0057] R 7 , R 8 and R 9 The monovalent organic group having one or more carbon atoms represented by the formula (I) may be any of a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, a monovalent araliphatic hydrocarbon group, and a monovalent alicyclic hydrocarbon group. The aliphatic groups in the aliphatic hydrocarbon group and the araliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. Examples of these hydrocarbon groups include linear, branched, or cyclic alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aralkyl groups, and aryl groups.

[0058] [ka] (In formula (6), R 10 represents a divalent organic group having one or more carbon atoms, and R 11 and R 12 each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

[0059] R 10 The divalent organic group having one or more carbon atoms represented by the formula (7) is preferably a group represented by the following formula (7). [ka] (In formula (7), R 5 , R 6 and R9 is R in the above formula (5). 5 , R 6 and R 9 are synonymous with the above. * represents a bond.)

[0060] R 5 When R is a divalent organic group having one or more carbon atoms, 5 is -(CH2) n It preferably has a structure represented by O- (n is an integer of 1 or more).

[0061] R 6 The divalent organic group having one or more carbon atoms represented by R may be any of a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, a divalent araliphatic hydrocarbon group, and a divalent alicyclic hydrocarbon group, and may be linear or branched. 6 is -(CH2) n It is preferable that the compound has a structure represented by - (n is an integer of 1 or more).

[0062] In formula (6), R 11 and R 12 The monovalent organic group having one or more carbon atoms represented by the formula (I) may be any of a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, a monovalent araliphatic hydrocarbon group, and a monovalent alicyclic hydrocarbon group. The aliphatic groups in the aliphatic hydrocarbon group and the araliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched. Examples of these hydrocarbon groups include linear, branched, or cyclic alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aralkyl groups, and aryl groups.

[0063] The heating temperature in step (b) can be between room temperature and 100° C., and preferably between 40° C. and 80° C. The heating time can be between 10 minutes and 24 hours, and preferably between 30 minutes and 12 hours.

[0064] The basic compound is not particularly limited, but is preferably a compound having a nitrogen atom, and particularly preferably a compound having ammonia or an amino group.

[0065] When ammonia is added as the basic compound, it is preferably added as aqueous ammonia with a concentration of 1 to 30 mass %.

[0066] Examples of compounds having an amino group include isopropylamine, amylamine, isoamylamine, dibutylamine, monoethanolamine, and tetramethylammonium hydroxide. ammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine, and diglycolamine are preferred.

[0067] In the step (b), the above basic compounds may be used singly or in combination of two or more.

[0068] 1.1.3. Process (c) Step (c) is a step of adding an alkoxysilane (C) having a polyalkylene oxide chain after step (b) and heating the mixture. In step (c), an appropriate amount of alkoxysilane (C) having a polyalkylene oxide chain is added to the particles obtained in step (b) and having a partial structure represented by general formula (3) and / or a partial structure represented by general formula (4) on their surfaces. This adds an appropriate amount of alkoxysilane (C) having a polyalkylene oxide chain to the particle surface as a graft chain, in addition to the partial structure represented by general formula (3) and / or the partial structure represented by general formula (4). Abrasive particles having polyalkylene oxide chains grafted onto their surfaces in this manner exhibit an enhanced steric hindrance effect, allowing for appropriate control of interactions between abrasive particles and with silicon oxide films. This suppresses the occurrence of polishing defects during polishing of silicon oxide films and also results in excellent polishing properties after storage.

[0069] The heating temperature in step (c) can be between room temperature and 100° C., and preferably between 40° C. and 80° C. The heating time can be between 10 minutes and 24 hours, and preferably between 30 minutes and 12 hours.

[0070] In step (c), an alkoxysilane (C) having a polyalkylene oxide chain is used. The alkoxysilane (C) having a polyalkylene oxide chain is not particularly limited as long as it is a compound that can hydrolyze the alkoxy group to generate a silanol group, which can bond to the particle surface by a dehydration condensation reaction with the hydroxyl group (-OH) remaining on the particle surface without reacting in step (a), thereby immobilizing the polyalkylene oxide chain on the particle surface. By reacting the alkoxysilane (C) having a polyalkylene oxide chain, the polyalkylene oxide chain can be easily immobilized on the particle surface.

[0071] The alkoxysilane (C) having a polyalkylene oxide chain preferably has two or three alkoxy groups bonded to a silicon atom. Examples of the alkoxy groups include lower alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, with methoxy and ethoxy being preferred.

[0072] The polyalkylene oxide chain preferably has at least one repeating unit selected from the group consisting of repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2). -(CH2CH2O)- (1) -(CHR 1 CH2O)- (2) (In the formula, R 1 is C m H 2m+1 where m is an integer of 1 to 4.

[0073] Specific examples of the polyalkylene oxide chain contained in the alkoxysilane (C) include -CH2-O-[(CH2CH2O) m -(CH(CH3)CH2O) n ]-C4H9, -CH2-O-(CH(CH3)CH2O) n -H, -CH2-O-(CH2CH2O) n -H, -CH2-O-(CH2CH2O) n—CH3, etc. In the formula, m and n are each an integer of 1 or more. These alkoxysilanes (C) having a polyalkylene oxide chain may be used alone or in combination of two or more.

[0074] 1.2. Second embodiment 1.2.1. Process (d) Step (d) is a step of heating a mixture containing particles having hydroxyl groups (-OH) fixed to the surface via covalent bonds and alkoxysilane (B) having an amino group. By passing through step (d), organic groups having amino groups are fixed to the surface of the particles, and at least one partial structure selected from the group consisting of partial structures represented by the following general formula (3) and partial structures represented by the following general formula (4) can be formed. -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0075] In step (d), the partial structure formed on the surface of the particle is preferably the partial structure represented by the above general formula (6) shown in the section on step (b).

[0076] The heating temperature in step (d) can be between room temperature and 100° C., and preferably between 40° C. and 80° C. The heating time can be between 10 minutes and 24 hours, and preferably between 30 minutes and 12 hours.

[0077] In step (d), as in step (a), particles having hydroxyl groups (-OH) immobilized on their surfaces via covalent bonds are used. Such particles having hydroxyl groups (-OH) immobilized on their surfaces via covalent bonds do not include particles having compounds having hydroxyl groups physically or ionically adsorbed on their surfaces.

[0078] As the particles having hydroxyl groups (-OH) fixed to the surface via covalent bonds, which are the raw material of the abrasive grains, particles such as silica similar to those used in step (a) can be preferably used.

[0079] In step (d), an alkoxysilane (B) having an amino group is used. The alkoxysilane (B) having an amino group is not particularly limited as long as it is a compound in which the alkoxy group is hydrolyzed to generate a silanol group, which can undergo a dehydration condensation reaction with the hydroxyl group (-OH) immobilized on the particle surface to bond to the particle surface. By reacting with the alkoxysilane (B) having an amino group, an organic group having an amino group can be easily immobilized on the particle surface.

[0080] The alkoxysilane (B) having an amino group is preferably an alkoxysilane having two or three alkoxy groups bonded to a silicon atom. Preferred alkoxy groups are lower alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, with methoxy and ethoxy being more preferred.

[0081] Specific examples of alkoxysilanes having an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane. Among these, 3-aminopropyltriethoxysilane is more preferred. These alkoxysilanes having an amino group may be used alone or in combination of two or more.

[0082] 1.2.2. Process (e) In step (e), the moiety represented by the general formula (3) is formed on the surface of the compound obtained in step (d). By adding an appropriate amount of alkoxysilane (C) having a polyalkylene oxide chain to particles having a partial structure and / or a partial structure represented by the general formula (4) and heating the mixture, polyalkylene oxide chains can be introduced as graft chains onto the particle surface in addition to the partial structure represented by the general formula (3) and / or the partial structure represented by the general formula (4). Abrasive particles having polyalkylene oxide chains grafted onto their surfaces in this manner have an increased steric hindrance effect, allowing for appropriate control of interactions between abrasive particles and with silicon oxide films. This reduces the occurrence of polishing defects during polishing of silicon oxide films and also results in excellent polishing properties after storage.

[0083] The heating temperature in step (e) can be between room temperature and 100° C., and preferably between 40° C. and 80° C. The heating time can be between 10 minutes and 24 hours, and preferably between 30 minutes and 12 hours.

[0084] In step (e), an alkoxysilane (C) having a polyalkylene oxide chain is used. The alkoxysilane (C) having a polyalkylene oxide chain is not particularly limited as long as it is a compound that can generate silanol groups by hydrolysis of the alkoxy groups, and bond to the particle surface by a dehydration condensation reaction with hydroxyl groups (-OH) remaining on the particle surface without reacting in step (d), thereby immobilizing the polyalkylene oxide chain on the particle surface. By reacting the alkoxysilane (C) having a polyalkylene oxide chain, the polyalkylene oxide chain can be easily immobilized on the particle surface.

[0085] As the alkoxysilane (C) having a polyalkylene oxide chain, the compounds exemplified in the above step (c) can be used.

[0086] 1.3.Characteristics of abrasive grains The abrasive grains obtained by the method according to this embodiment have the following characteristics.

[0087] Zeta potential The zeta potential of the abrasive grains produced by the method of this embodiment in a chemical mechanical polishing composition is preferably 10 mV or higher, more preferably 15 mV or higher, and particularly preferably 20 mV or higher. Furthermore, the zeta potential of the abrasive grains in a chemical mechanical polishing composition is preferably 40 mV or lower, more preferably 35 mV or lower. The abrasive grains produced by the method of this embodiment can be added to the chemical mechanical polishing composition described below. When the zeta potential of the abrasive grains in the chemical mechanical polishing composition is within the above range, the abrasive grains approach the silicon oxide film due to electrostatic attraction, and the electrostatic repulsion between the abrasive grains effectively prevents particle aggregation. This allows for rapid polishing of silicon oxide films and may also result in excellent polishing properties after storage. To achieve a zeta potential within the above range, the pH of the chemical mechanical polishing composition is preferably 2 to 6. In order to make the zeta potential of the abrasive grains 10 mV or more in any pH range of 2 or more and 6 or less of the chemical mechanical polishing composition, it can be adjusted, for example, by increasing or decreasing the amount of alkoxysilane (A) having an epoxy group used in step (a), the amount of basic compound used in step (b), and the amount of alkoxysilane (B) having an amino group used in step (d).

[0088] The zeta potential of the abrasive grains can be measured by a conventional method using a zeta potential measuring device that uses the laser Doppler method as its measurement principle. Examples of such zeta potential measuring devices include the "Zeta Potential Analyzer" manufactured by Brookhaven Instruments, the "ELSZ-1000ZS" manufactured by Otsuka Electronics Co., Ltd., and the "DT-300" manufactured by Dispersion Technology.

[0089] 1.3.2. Average secondary particle size The average secondary particle size of the abrasive grains produced by the method of this embodiment is preferably 30 nm or more, more preferably 40 nm or more, and particularly preferably 50 nm or more. The average secondary particle size of the abrasive grains produced by the method of this embodiment is preferably 100 nm or less, more preferably 95 nm or less, and particularly preferably 90 nm. The average secondary particle size of the abrasive grains can be measured using a dynamic light scattering particle size distribution analyzer. An example of such a dynamic light scattering particle size distribution analyzer is the "Nanoparticle Analyzer SZ-100" manufactured by HORIBA Corporation.

[0090] 2. Chemical mechanical polishing composition The chemical mechanical polishing composition according to one embodiment of the present invention contains abrasive grains produced by the above-described method and a liquid medium. Hereinafter, each component that can be contained in the chemical mechanical polishing composition according to this embodiment will be described in detail.

[0091] 2.1.Abrasive grain The chemical mechanical polishing composition according to this embodiment contains abrasive grains (hereinafter also referred to as "specific abrasive grains") produced by the above-described method. The abrasive grains produced by the above-described method have polyalkylene oxide chains covalently grafted to their surfaces and at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4). -NR 2 R 3 ····(3) -N + R 2 R 3 R 4 M - ····(4) (In the above formulas (3) and (4), R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0092] The polyalkylene oxide chain grafted to the surface of the abrasive grain by a covalent bond preferably has at least one repeating unit selected from the group consisting of repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2): -(CH2CH2O)- (1) -(CHR 1 CH2O)- (2) (In the formula, R 1 is C m H 2m+1 where m is an integer of 1 to 4.

[0093] Specific examples of polyalkylene oxide chains include -CH2-O-[(CH2CH2O) m -(CH(CH3)CH2O) n ]-C4H9, -CH2-O-(CH(CH3)CH2O) n -H, -CH2-O-(CH2CH2O) n -H, -CH2-O-(CH2CH2O) n In the formula, m and n are each an integer of 1 or more.

[0094] The specific abrasive grains have amino groups on their surface, which gives them a zeta potential of 0 mV or higher in an acidic chemical mechanical polishing composition. Therefore, in the acidic chemical mechanical polishing composition, the specific abrasive grains approach the silicon oxide film due to electrostatic attraction, and the electrostatic repulsion between the specific abrasive grains effectively prevents particle aggregation. This allows for high-speed polishing of silicon oxide films and excellent polishing properties after storage. Furthermore, the introduction of polyalkylene oxide chains on the surface enhances the steric hindrance effect of the specific abrasive grains. This reduces the occurrence of polishing defects during polishing of silicon oxide films and improves polishing properties after storage.

[0095] The content of the specific abrasive grains is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and particularly preferably 0.5 mass% or more, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. The content of the specific abrasive grains is preferably 20 mass% or less, more preferably 10 mass% or less, when the total mass of the chemical mechanical polishing composition is taken as 100 mass%. When the content of the specific abrasive grains is within this range, the silicon oxide film can be polished at high speed, the occurrence of polishing defects during polishing of the silicon oxide film can be suppressed, and the polishing properties of the chemical mechanical polishing composition after storage can be improved.

[0096] 2.2. Liquid Media The chemical mechanical polishing composition according to this embodiment contains a liquid medium. Examples of the liquid medium include water, a mixed medium of water and alcohol, and a mixed medium containing water and an organic solvent compatible with water. Among these, it is preferable to use water or a mixed medium of water and alcohol, and it is more preferable to use water. The water is not particularly limited, but pure water is preferred. The water may be blended as the remainder of the constituent materials of the chemical mechanical polishing composition, and there is no particular limitation on the water content.

[0097] 2.3. Other additives The chemical mechanical polishing composition according to this embodiment may further contain, as needed, additives such as an acidic compound, an iron (III) compound, an oxidizing agent, a water-soluble polymer, a surfactant, a corrosion inhibitor, a pH adjuster, a nitrogen-containing heterocyclic compound, etc. Each additive is described below.

[0098] <Acidic compounds> The chemical mechanical polishing composition according to this embodiment may contain an acidic compound. By containing the acidic compound, the polishing properties of the chemical mechanical polishing composition after storage may be improved due to a synergistic effect with the specific abrasive grains.

[0099] Such acidic compounds include organic acids and inorganic acids. Examples of organic acids include saturated carboxylic acids such as malonic acid, citric acid, malic acid, tartaric acid, oxalic acid, lactic acid, and iminodiacetic acid; unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-butenoic acid, 2-methyl-3-butenoic acid, 2-hexenoic acid, and 3-methyl-2-hexenoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2-pentenedioic acid, itaconic acid, allylmalonic acid, isopropylidenesuccinic acid, 2,4-hexadienedioic acid, and acetylenedicarboxylic acid; and aromatic carboxylic acids such as trimellitic acid, and salts thereof. Examples of inorganic acids include phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and salts thereof. These acidic compounds may be used alone or in combination of two or more.

[0100] When the chemical mechanical polishing composition of this embodiment contains an acidic compound, the content of the acidic compound is preferably 0.001 to 5 mass%, more preferably 0.002 to 1 mass%, and particularly preferably 0.003 to 0.5 mass%, when the total mass of the chemical mechanical polishing composition is 100 mass%.

[0101] <Oxidizing agent> The chemical mechanical polishing composition according to this embodiment may contain an oxidizing agent.

[0102] Examples of oxidizing agents include ammonium persulfate, potassium persulfate, hydrogen peroxide, diammonium cerium nitrate, potassium hypochlorite, ozone, potassium periodate, and peracetic acid. Among these oxidizing agents, ammonium persulfate, potassium persulfate, and hydrogen peroxide are preferred, with hydrogen peroxide being more preferred, in consideration of oxidizing power and ease of handling. These oxidizing agents may be used alone or in combination of two or more.

[0103] When the chemical mechanical polishing composition according to this embodiment contains an oxidizing agent, the content of the oxidizing agent is preferably 0.1% by mass when the total mass of the chemical mechanical polishing composition is taken as 100% by mass. The oxidizing agent is preferably added immediately before the CMP polishing step because it is easily decomposed in the chemical mechanical polishing composition.

[0104] <Water-soluble polymer> The chemical mechanical polishing composition according to this embodiment may contain a water-soluble polymer. The water-soluble polymer adsorbs to the surface to be polished and reduces polishing friction. This effect may reduce the occurrence of dishing on the surface to be polished.

[0105] Examples of water-soluble polymers include polyethyleneimine, poly(meth)acrylamide, poly(N-alkyl(meth)acrylamide), poly(meth)acrylic acid, polyoxyethylene alkylamine, polyvinyl alcohol, polyvinyl alkyl ether, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, copolymers of (meth)acrylic acid and maleic acid, and polymeric amine compounds such as poly(meth)acrylamine. Among these, the addition of thermoresponsive polymers such as polyvinyl methyl ether and poly(N-isopropylacrylamide) or polymeric amine compounds such as poly(meth)acrylamine may effectively reduce the occurrence of dishing on the polished surface without reducing the polishing rate for the polished surface.

[0106] The weight-average molecular weight (Mw) of the water-soluble polymer is preferably 1,000 to 1,000,000, more preferably 3,000 to 800,000. When the weight-average molecular weight of the water-soluble polymer is within this range, it is more likely to be adsorbed to the polished surface, which may further reduce polishing friction. As a result, the occurrence of dishing on the polished surface may be effectively reduced. In this specification, the "weight-average molecular weight (Mw)" refers to the weight-average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography).

[0107] When the chemical mechanical polishing composition of this embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.005 to 0.5 mass%, and more preferably 0.01 to 0.2 mass%, when the total mass of the chemical mechanical polishing composition is 100 mass%.

[0108] The content of the water-soluble polymer depends on the weight-average molecular weight (Mw) of the water-soluble polymer, but is preferably adjusted so that the viscosity of the chemical mechanical polishing composition is 0.5 mPa·s or more and less than 10 mPa·s at 25° C. When the viscosity of the chemical mechanical polishing composition at 25° C. is 0.5 mPa·s or more and less than 10 mPa·s, the surface to be polished can be easily polished at high speed, and the appropriate viscosity allows the chemical mechanical polishing composition to be stably applied to the polishing cloth.

[0109] <Surfactant> The chemical mechanical polishing composition according to this embodiment may contain a surfactant. The inclusion of a surfactant may impart an appropriate viscosity to the chemical mechanical polishing composition. The viscosity of the chemical mechanical polishing composition is preferably adjusted to 0.5 mPa·s or more and less than 10 mPa·s at 25°C.

[0110] The surfactant is not particularly limited, and examples thereof include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0111] Examples of anionic surfactants include fatty acid soaps, carboxylates such as alkyl ether carboxylates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, Examples of the surfactant include sulfonates such as α-olefin sulfonates; sulfates such as higher alcohol sulfates, alkyl ether sulfates, and polyoxyethylene alkylphenyl ether sulfates; and fluorine-containing surfactants such as perfluoroalkyl compounds. Examples of the cationic surfactant include aliphatic amine salts and aliphatic ammonium salts. Examples of the nonionic surfactant include nonionic surfactants having a triple bond such as acetylene glycol, acetylene glycol ethylene oxide adducts, and acetylene alcohol; and polyethylene glycol surfactants. These surfactants may be used alone or in combination of two or more.

[0112] When the chemical mechanical polishing composition of this embodiment contains a surfactant, the content of the surfactant is preferably 0.001 to 5 mass%, more preferably 0.003 to 3 mass%, and particularly preferably 0.005 to 1 mass%, when the total mass of the chemical mechanical polishing composition is 100 mass%.

[0113] <Corrosion inhibitor> The chemical mechanical polishing composition according to this embodiment may contain a corrosion inhibitor. Examples of corrosion inhibitors include benzotriazole and its derivatives. Here, the benzotriazole derivative refers to a compound in which one or more hydrogen atoms of benzotriazole have been substituted with, for example, a carboxy group, a methyl group, an amino group, or a hydroxy group. Specific examples of the benzotriazole derivative include 4-carboxybenzotriazole, 7-carboxybenzotriazole, benzotriazole butyl ester, 1-hydroxymethylbenzotriazole, 1-hydroxybenzotriazole, and salts thereof.

[0114] When the chemical mechanical polishing composition of this embodiment contains a corrosion inhibitor, the content of the corrosion inhibitor is preferably 1 mass % or less, and more preferably 0.001 to 0.1 mass %, when the total mass of the chemical mechanical polishing composition is 100 mass %.

[0115] <pH adjuster> The chemical mechanical polishing composition according to this embodiment may further contain a pH adjuster as needed. Examples of the pH adjuster include acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; bases such as potassium hydroxide, ethylenediamine, monoethanolamine, TMAH (tetramethylammonium hydroxide), TEAH (tetraethylammonium hydroxide), and ammonia. One or more of these can be used.

[0116] <Nitrogen-containing heterocyclic compound> The chemical mechanical polishing composition according to this embodiment may contain a nitrogen-containing heterocyclic compound. By containing a nitrogen-containing heterocyclic compound, the polished surface is protected, so the occurrence of defects on the polished surface may be reduced.

[0117] The nitrogen-containing heterocyclic compound is an organic compound containing at least one heterocyclic ring selected from a heterocyclic five-membered ring and a heterocyclic six-membered ring having at least one nitrogen atom. Specific examples of the heterocyclic ring include heterocyclic five-membered rings such as a pyrrole structure, an imidazole structure, a triazole structure, and a thiazoline structure; and heterocyclic six-membered rings such as a pyridine structure, a pyrimidine structure, a pyridazine structure, and a pyrazine structure. The heterocyclic ring may form a condensed ring. Specifically, an indole structure, an isoindole structure, a benzimidazole structure, a benzotriazole structure, an isothiazoline structure, a quinoline structure, an isoquinoline structure, a quinazoline structure, a cinnoline structure, a phthalazine structure, a quinoxaline structure, an acridine structure, etc. are included. Among the heterocyclic compounds having such structures, heterocyclic compounds having a pyridine structure, a quinoline structure, a benzimidazole structure, a benzotriazole structure, and an isothiazoline structure are preferred.

[0118] 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, isothiazolinone, and derivatives having these skeletons.Among these, at least one selected from benzotriazole, isothiazolinone, and triazole is preferred.These nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

[0119] 2.4.pH The pH of the chemical mechanical polishing composition according to this embodiment is preferably 2 or more and 6 or less, more preferably 2 or more and 5 or less. When the pH of the chemical mechanical polishing composition is within the above range, the dispersibility of the specific abrasive grains is improved, which is preferable because the storage stability of the chemical mechanical polishing composition is improved.

[0120] The pH of the chemical mechanical polishing composition according to this embodiment can be adjusted by, for example, appropriately increasing or decreasing the content of the acidic compound, the pH adjuster, or the like.

[0121] In this specification, pH refers to hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, a tabletop pH meter manufactured by Horiba, Ltd.) under conditions of 25°C and 1 atmosphere.

[0122] 2.5.Applications According to one aspect of the chemical mechanical polishing composition of this embodiment, it can be used to polish excess silicon oxide film on an insulating film (e.g., a silicon oxide film), for example, during trench isolation (STI) to electrically isolate adjacent transistors. Also, according to one aspect of the chemical mechanical polishing composition of this embodiment, it can be used as an abrasive for polishing silicon oxide film at high speed.

[0123] 2.6. Method for preparing chemical mechanical polishing composition The chemical mechanical polishing composition according to this embodiment can be prepared by dissolving or dispersing the above-described components in a liquid medium such as water. The dissolving or dispersing method is not particularly limited, and any method may be used as long as it can uniformly dissolve or disperse the components. Furthermore, the mixing order and mixing method of the above-described components are not particularly limited.

[0124] The chemical mechanical polishing composition according to this embodiment can also be prepared as a concentrated stock solution and diluted with a liquid medium such as water before use.

[0125] 3. Polishing method A polishing method according to one embodiment of the present invention includes a step of polishing a semiconductor substrate using the above-described chemical mechanical polishing composition. This chemical mechanical polishing composition can polish a silicon oxide film at a high speed on the polishing surface of a semiconductor substrate containing the silicon oxide film, while reducing the occurrence of polishing defects. Furthermore, when this chemical mechanical polishing composition is stored, it exhibits excellent storage stability and excellent polishing properties after storage. Therefore, the polishing method according to this embodiment is particularly suitable for polishing a semiconductor substrate having a silicon oxide film formed thereon, for example.

[0126] In the process of polishing a semiconductor substrate using the above-mentioned chemical mechanical polishing composition, the chemical mechanical polishing composition is supplied to a polishing pad on a polishing table, brought into contact with the surface to be polished, and the surface to be polished and the polishing pad are moved relative to each other to perform polishing. A general polishing apparatus having a polishing platen with a polishing pad attached thereto can be used. The polishing pad can be made of a general nonwoven fabric, polyurethane foam, porous fluororesin, or the like. During polishing, a chemical mechanical polishing composition is continuously supplied to the polishing pad using a pump or the like. There is no limit to the amount of supply, but it is preferable to keep the surface of the polishing pad constantly covered with the chemical mechanical polishing composition. After polishing, the semiconductor substrate is preferably thoroughly washed with running water, and then dried using a spin dryer or the like to remove any water droplets adhering to the semiconductor substrate.

[0127] For example, the chemical mechanical polishing composition described above can be used for trench isolation (STI). In trench isolation, an excess silicon oxide film needs to be removed by CMP, and the chemical mechanical polishing composition described above can be suitably used to polish this silicon oxide film.

[0128] The above-described polishing step can be performed using a polishing apparatus 100 such as that shown in FIG. 1. FIG. 1 is a schematic perspective view of the polishing apparatus 100. The above-described polishing step is performed by supplying a slurry (chemical mechanical polishing composition) 14 from a slurry supply nozzle 12 and rotating a turntable 18 to which a polishing pad 16 is attached while bringing a carrier head 22 holding a semiconductor substrate 20 into contact with the turntable. Note that FIG. 1 also shows a water supply nozzle 24 and a dresser 26.

[0129] The polishing load of the carrier head 22 can be selected within a range of 0.7 to 70 psi, preferably 1.5 to 35 psi. The rotation speed of the turntable 18 and the carrier head 22 can be appropriately selected within a range of 10 to 400 rpm, preferably 30 to 150 rpm. The flow rate of the slurry (chemical mechanical polishing composition) 14 supplied from the slurry supply nozzle 12 can be selected within a range of 10 to 1,000 mL / min, preferably 50 to 400 mL / min.

[0130] Commercially available polishing machines include, for example, Ebara Corporation models "EPO-112," "EPO-222," and "F-REX300SII"; Lapmaster SFT models "LGP-510" and "LGP-552"; Applied Materials models "Mirra" and "Reflexion"; and G&P Technology models "POLI-400L" and "POLI-762."

[0131] 4. Working Example The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0132] Example 1 4.1.1. Synthesis of alkoxysilanes (C) with polyalkylene oxide chains 100 parts by mass of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a solvent, 5 parts by mass of (3-mercaptopropyl)triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) as an alkoxysilane having a sulfanyl group, and 50 parts by mass of a polyether having an allyl group (product name "Unisafe PKA-5015", manufactured by NOF Corporation, average molecular weight 1600) were mixed and stirred at 25 ° C for 10 minutes. Next, 0.15 parts by mass of N,N'-azobisisobutyronitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a radical initiator was added, and the mixture was further stirred at 60 ° C for 3 hours. Then, the mixture was distilled under reduced pressure at 90 ° C for 3 hours to obtain alkoxysilane C-1 having a polyalkylene oxide chain.

[0133] 4.1.2. Preparation of Abrasive Grain A-1 100 parts by weight of silica sol (product name "BS-3", manufactured by Fuso Chemical Co., Ltd., an aqueous dispersion containing 20% ​​silica particles by weight) was mixed with 0.4 parts by weight of (3-glycidyloxypropyl)trimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and heated at 60°C for 2 hours. Subsequently, 4 parts by weight of ammonia (manufactured by Tokyo Chemical Industry Co., Ltd., 28% aqueous solution) was added as a basic compound, and the mixture was heated at 60°C for another 2 hours. Next, 5 parts by weight of the alkoxysilane synthesized in Section 4.1.1. Synthesis of alkoxysilane having polyalkylene oxide chains was added, and the mixture was heated at 60°C for 2 hours. Finally, the temperature was raised to 100°C, and pure water was added to maintain the volume of the dispersion while the by-product alcohol was distilled off, yielding an aqueous dispersion containing 20% ​​by weight of abrasive grain A-1.

[0134] 4.1.3. Preparation of Chemical Mechanical Polishing Composition Abrasive grains, acid, other additives, and water as a liquid medium were added to a 1 L polyethylene bottle to obtain the composition shown in Table 1 below. Next, the pH was adjusted as needed by adding nitric acid (Kanto Chemical Co., Ltd., 60% aqueous solution) or potassium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd., 85% aqueous solution) to obtain the pH shown in Table 1 below. The mixture was then filtered through a 0.3 μm pore filter to obtain a chemical mechanical polishing composition. The pH of the chemical mechanical polishing composition was measured at 25°C and 1 atmosphere using a commercially available pH meter (Horiba, Ltd., model "F52").

[0135] Evaluation Method 4.1.4.1. Evaluation of Silicon Oxide Film Removal Rate Using the chemical mechanical polishing composition obtained above, a 12-inch silicon substrate with a 2000 nm silicon oxide film was polished using a chemical mechanical polishing machine (manufactured by G&P Technology, model "POLI-400L") under the following conditions. The evaluation criteria for the silicon oxide film removal rate are as follows. The results are shown in Table 1 below. The thickness of the silicon oxide film before and after polishing was measured using a non-contact optical film thickness measuring device (Nanometrics Japan, model "NanoSpec 6100"). <Polishing conditions> Polishing pad: Nitta DuPont, model number "IC1000" Carrier head load: 129g / cm 2 Platen rotation speed: 100 rpm Polishing head rotation speed: 90 rpm ·Chemical mechanical polishing composition supply amount: 50mL / min <Evaluation criteria> "A": When the polishing speed of silicon oxide film is 500 Å / min or more, it is judged to be extremely good because it is possible to process semiconductors extremely efficiently in actual semiconductor polishing. "B": When the polishing rate of silicon oxide film is 300 Å / min or more and less than 500 Å / min, it is judged as very good because it is possible to process semiconductors efficiently in actual semiconductor polishing. "C": When the polishing rate of silicon oxide film is 100 Å / min or more and less than 300 Å / min, it is judged as good because it is possible to process semiconductors within the allowable time range in actual semiconductor polishing. "D": When the polishing speed of the silicon oxide film is less than 100 Å / min, it is judged to be defective because it will hinder the semiconductor throughput in actual semiconductor polishing.

[0136] 4.1.4.2. Defect Assessment Using the chemical mechanical polishing composition obtained above, a chemical mechanical polishing test was carried out for 60 seconds under the following polishing conditions on a 12-inch diameter wafer with a 2000 nm thick silicon oxide film as the object to be polished. <Polishing conditions> Polishing equipment: AMAT, model "Reflexion LK" Polishing pad: Fujibo Holdings Co., Ltd., "Multi-hard polyurethane pad; H800-type1(3-1S)775" ·Chemical mechanical polishing composition supply rate: 300mL / min Platen rotation speed: 100 rpm Head rotation speed: 90 rpm Head pressure: 2.5 psi

[0137] Next, the silicon oxide film-coated wafers polished as described above were inspected in dark field mode using a defect inspection system (KLA-Tencor Corporation, model "Surfscan SP2") to observe defects of 0.115 μm or larger. The evaluation criteria for defect evaluation are as follows. The results are also shown in Table 1 below. <Evaluation criteria> "A": If the total number of defects is less than 10, it is judged to be extremely good, since quality defects are extremely unlikely to occur in actual semiconductor polishing. "B": If the total number of defects is between 10 and 30, it is judged to be very good because it is unlikely that quality defects will occur in actual semiconductor polishing. "C": If the total number of defects is 30 or more, it is judged to be defective because it is likely to cause quality defects in actual semiconductor polishing and will cause problems.

[0138] 4.1.4.3. Evaluation of polishing properties after storage The chemical mechanical polishing composition obtained above was stored at 60°C and atmospheric pressure for one week. The stored chemical mechanical polishing composition was used to evaluate the polishing rate of a silicon oxide film and evaluate defects, thereby evaluating the polishing characteristics of the chemical mechanical polishing composition after storage. The evaluation methods and criteria were in accordance with "4.1.4.1. Evaluation of the polishing rate of a silicon oxide film" and "4.1.4.2. Evaluation of defects" above. The results are shown in Table 1 below.

[0139] 4.2. Examples 2 and 3 Alkoxysilanes C-2 and C-3 having polyalkylene oxide chains were synthesized in the same manner as in Example 1, except that in the section "4.1.1. Synthesis of alkoxysilane having polyalkylene oxide chains," the types and amounts of the solvent, alkoxysilane having a sulfanyl group, polyether having an allyl group, and radical initiator were changed as shown in Table 1 below.

[0140] Next, in the section "4.1.2. Preparation of Abrasive Grains," abrasive grains B-1 and C-1 were each prepared in the same manner as in Example 1, except that the types and amounts of silica particles, alkoxysilane having an epoxy group, basic compound, and alkoxysilane having a polyalkylene oxide chain were changed as shown in Table 1 below.

[0141] Furthermore, in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, a chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0142] Example 4 4.3.1. Synthesis of alkoxysilanes bearing polyalkylene oxide chains 100 parts by mass of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a solvent, 34 parts by mass of (3-mercaptopropyl)triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) as an alkoxysilane having a sulfanyl group, and 300 parts by mass of a polyether having an allyl group (product name "Uniox PKA-5005", manufactured by NOF Corporation, average molecular weight 1600) were mixed and stirred at 25°C for 10 minutes. Next, 4 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a radical initiator were added, and the mixture was stirred at 25°C for 10 minutes. The mixture was further stirred for 3 hours at 60° C., followed by vacuum distillation for 3 hours at 90° C. to obtain alkoxysilane C-4 having a polyalkylene oxide chain.

[0143] 4.3.2. Preparation of Abrasive Grain D-1 100 parts by weight of silica sol (product name "BS-1", manufactured by Fuso Chemical Co., Ltd., aqueous dispersion containing 20% ​​by weight of silica particles) was mixed with 0.2 parts by weight of (3-aminopropyl)triethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and heated at 60°C for 2 hours. Then, 0.1 parts by weight of alkoxysilane C-4 synthesized in Section "4.3.1. Synthesis of alkoxysilane having polyalkylene oxide chain" was added, and the mixture was heated at 60°C for 2 hours. Finally, the temperature was raised to 100°C, and pure water was added to maintain the volume of the dispersion while the by-product alcohol was distilled off, yielding an aqueous dispersion containing 20% ​​by weight of abrasive grain D-1.

[0144] 4.3.3. Preparation and Evaluation of Chemical Mechanical Polishing Compositions A chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0145] 4.4. Comparative Example 1 4.4.1. Synthesis of alkoxysilanes with polyalkylene oxide chains 100 parts by mass of methanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a solvent, 60 parts by mass of (3-mercaptopropyl)trimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) as an alkoxysilane having a sulfanyl group, and 140 parts by mass of a polyether having an allyl group (product name "Uniox PKA-5008", manufactured by NOF Corporation, average molecular weight 450) were mixed and stirred at 25 ° C for 10 minutes. Next, 0.8 parts by mass of N,N'-azobisisobutyronitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a radical initiator was added, and the mixture was further stirred at 60 ° C for 3 hours. Then, the mixture was distilled under reduced pressure at 90 ° C for 3 hours to obtain alkoxysilane C-5 having a polyalkylene oxide chain.

[0146] 4.4.2. Preparation of Abrasive Grain E-1 100 parts by mass of silica sol (product name "PL-5", manufactured by Fuso Chemical Co., Ltd., aqueous dispersion containing 20% ​​by mass of silica particles) converted to silica mass was mixed with 5 parts by mass of alkoxysilane C-5 synthesized in Section "4.4.1. Synthesis of alkoxysilane having polyalkylene oxide chains" and heated at 60°C for 2 hours. The temperature was then raised to 100°C, and pure water was added to maintain the volume of the dispersion while the by-product alcohol was distilled off, yielding an aqueous dispersion containing 20% ​​by mass of abrasive grains E-1.

[0147] 4.4.3. Preparation and Evaluation of Chemical Mechanical Polishing Compositions A chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0148] 4.5. Comparative Example 2 4.5.1. Preparation of Abrasive Grain A-2 100 parts by weight of silica sol (product name "BS-3", manufactured by Fuso Chemical Co., Ltd., an aqueous dispersion containing 20% ​​by weight of silica particles) converted to silica mass was mixed with 0.8 parts by weight of (3-glycidyloxypropyl)trimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and heated at 60°C for 2 hours. Then, 8 parts by weight of ammonia (manufactured by Tokyo Chemical Industry Co., Ltd., 28% aqueous solution) was added, and the mixture was heated at 60°C for 2 hours. Finally, the temperature was raised to 100°C, and pure water was added to maintain the volume of the dispersion while the by-product alcohol was distilled off, yielding an aqueous dispersion containing 20% ​​by weight of abrasive grain A-2.

[0149] 4.5.2. Preparation and Evaluation of Chemical Mechanical Polishing Compositions A chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0150] 4.6. Comparative Example 3 4.6.1. Preparation and Evaluation of Chemical Mechanical Polishing Compositions Silica sol (product name "PL-3L", manufactured by Fuso Chemical Co., Ltd., an aqueous dispersion containing 20% ​​by mass of silica particles) was used as abrasive C-2, and a chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0151] 4.7. Comparative Example 4 4.7.1. Preparation of Abrasive Grain B-2 100 parts by weight of silica sol (product name "PL-3", manufactured by Fuso Chemical Co., Ltd., an aqueous dispersion containing 20% ​​by weight of silica particles) was mixed with 0.2 parts by weight of (3-glycidyloxypropyl)trimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) and heated at 60°C for 2 hours. 0.4 parts by weight of ammonia (manufactured by Tokyo Chemical Industry Co., Ltd., 28% aqueous solution) was then added, and the mixture was heated at 60°C for another 2 hours. Next, 1 part by weight of trimethoxy-n-octylsilane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was heated at 60°C for 2 hours. Finally, the temperature was raised to 100°C, and pure water was added to maintain the volume of the dispersion while the by-product alcohol was distilled off, yielding an aqueous dispersion containing 20% ​​by weight of abrasive grain B-2.

[0152] 4.7.2. Preparation and Evaluation of Chemical Mechanical Polishing Compositions A chemical mechanical polishing composition was prepared and evaluated in the same manner as in Example 1, except that in section "4.1.3. Preparation of chemical mechanical polishing composition" of Example 1, the types and amounts of abrasive grains, acid, and other additives were changed as shown in Table 1 below. The results are shown in Table 1 below.

[0153] 4.8.Evaluation Results Table 1 below shows the reagents and amounts (parts by mass) used in the synthesis of alkoxysilane (C) having a polyalkylene oxide chain, preparation of abrasive grains, and preparation of chemical mechanical polishing composition in each example and comparative example, as well as the evaluation results of each chemical mechanical polishing composition.

[0154] [Table 1]

[0155] The reagents used in Examples 1 to 4 and Comparative Examples 1 to 4 are as follows: For those with component concentrations listed, the component concentrations were assumed to be the concentrations shown in Table 1 above, and for those without component concentrations listed, the component was assumed to be 100% in the product or reagent. <Solvent> Ethanol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Ethanol" Methanol: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Methanol" <Alkoxysilane with sulfanyl group> (3-Mercaptopropyl)methyldimethoxysilane: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "(3-Mercaptopropyl)methyldimethoxysilane" (3-Mercaptopropyl)trimethoxysilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "(3-Mercaptopropyl)trimethoxysilane" (3-Mercaptopropyl)triethoxysilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "(3-Mercaptopropyl)triethoxysilane" <Polyether containing allyl groups> Unisafe PKA-5015: NOF Corporation, average molecular weight 1600, product name "Unisafe PKA-5015" Unisafe PKA-5014TF: NOF Corporation, average molecular weight 1500, product name "Unisafe PKA-5014TF" Uniox PKA-5001: NOF Corporation, average molecular weight 200, product name "Uniox PKA-5001" Uniox PKA-5005: NOF Corporation, average molecular weight 1500, product name "Uniox PKA-5005" Uniox PKA-5008: NOF Corporation, average molecular weight 450, product name "Uniox PKA-5008" <Radical initiator> N,N'-Azobisisobutyronitrile: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "N,N'-Azobisisobutyronitrile" 2,2'-Azobis(2,4-dimethylvaleronitrile): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "2,2'-Azobis(2,4-dimethylvaleronitrile)" 2,2'-Azobis(2-methylbutyronitrile): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "2,2'-Azobis(2-methylbutyronitrile)" <Silica particles> BS-3: Manufactured by Fuso Chemical Co., Ltd., component concentration 20% by mass, product name "BS-3" PL-3: Manufactured by Fuso Chemical Co., Ltd., ingredient concentration 20% by mass, product name "PL-3" PL-3L: Manufactured by Fuso Chemical Co., Ltd., ingredient concentration 20% by mass, product name "PL-3L" BS-1: Manufactured by Fuso Chemical Co., Ltd., component concentration 20% by mass, product name "BS-1" PL-5: Manufactured by Fuso Chemical Co., Ltd., ingredient concentration 20% by mass, product name "PL-5" <Alkoxysilane with epoxy group> (3-Glycidyloxypropyl)trimethoxysilane: Shin-Etsu Silicone Co., Ltd., product name "KBM-403" 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane" (3-Glycidyloxypropyl)dimethoxymethylsilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "3-glycidyloxypropyldimethoxymethylsilane" <Alkoxysilane with amino group> (3-Aminopropyl)triethoxysilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "3-aminopropyltriethoxysilane" <Basic compounds> Ammonia: 28% ammonia solution, manufactured by Tokyo Chemical Industry Co., Ltd. <Alkoxysilane with alkyl chains in the molecule> · Trimethoxy-n-octylsilane: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Trimethoxy-n-octylsilane" <Acid> · Phosphoric acid: Manufactured by Lasa Industries Co., Ltd., product name "85% Phosphoric Acid", component concentration 85% · Citric acid: Manufactured by Fuso Chemical Industry Co., Ltd., product name "Purified Citric Acid (Crystal) L" · Sulfuric acid: Manufactured by Kanto Chemical Co., Inc., product name "High-Purity Sulfuric Acid (96%)", component concentration 96% · Acetic acid: Manufactured by Kanto Chemical Co., Inc., product name "Acetic Acid" <Other additives> · Sodium lauryldiminodipropionate: Manufactured by Takemoto Yushi Co., Ltd., product name "Takesurf C-158D", component concentration 30% by mass · 5-Chloro-2-methyl-4-isothiazolin-3-one: Manufactured by Fujifilm Wako Pure Chemical Corporation, product name "5-Chloro-2-methyl-3-isothiazolone" · 2-Methyl-4-isothiazolin-3-one: Manufactured by Sigma-Aldrich, product name "2-Methyl-4-isothiazolin-3-one" <pH adjuster> · Nitric acid: Manufactured by Kanto Chemical Co., Inc., product name "Nitric Acid 1.38", component concentration 60% · Potassium hydroxide: Manufactured by Fujifilm Wako Pure Chemical Corporation, product name "Potassium Hydroxide", component concentration 85%

[0156] In Examples 1, 2, and 3, by passing through steps (a), (b), and (c), abrasive grains were obtained in which amino groups and polyalkylene oxide chains as graft chains were introduced via covalent bonds on their surfaces. By using a chemical mechanical polishing composition containing the abrasive grains, an acid, and other additives, the occurrence of polishing defects during the polishing of a silicon oxide film was suppressed, and moreover, the silicon oxide film could be polished at high speed. It was also found that the polishing characteristics were excellent even after storage of the chemical mechanical polishing composition.

[0157] In Example 4, steps (d) and (e) were performed to obtain abrasive grains having amino groups and polyalkylene oxide chains as graft chains introduced to their surfaces via covalent bonds. By using a chemical mechanical polishing composition containing the abrasive grains, acid, and other additives, the occurrence of polishing defects during polishing of silicon oxide films was suppressed, and the silicon oxide films were polished at high speed. Furthermore, it was found that the chemical mechanical polishing composition maintained excellent polishing properties even after storage.

[0158] In Comparative Example 1, no epoxy- or amino-alkoxysilane was added during the preparation of the abrasive grains, resulting in abrasive grains with only polyalkylene oxide chains grafted onto their surfaces via covalent bonds. When a chemical mechanical polishing composition containing the abrasive grains, acid, and other additives was used, the removal rate of silicon oxide films significantly decreased.

[0159] In Comparative Example 2, the abrasive grains were prepared without adding an alkoxysilane having a polyalkylene oxide chain, resulting in abrasive grains with only amino groups introduced onto their surfaces via covalent bonds. When a chemical mechanical polishing composition containing the abrasive grains, acid, and other additives was used, the polishing defect characteristics deteriorated, and the removal rate of the chemical mechanical polishing composition decreased after storage.

[0160] In Comparative Example 3, abrasive grains having neither amino groups nor polyalkylene oxide chains on their surfaces were used. A chemical mechanical polishing composition containing the abrasive grains, an acid, and other additives was used. When used, the polishing rate of silicon oxide film decreased immediately after preparation, and the polishing defect characteristics also deteriorated immediately after preparation.

[0161] In Comparative Example 4, an alkoxysilane having an alkyl chain in the molecule was added instead of an alkoxysilane having a polyalkylene oxide chain in the preparation of the abrasive grains, resulting in abrasive grains with amino and alkyl groups introduced onto the surface via covalent bonds. When a chemical mechanical polishing composition containing the abrasive grains, acid, and other additives was used, the polishing defect characteristics deteriorated, and the performance of the chemical mechanical polishing composition deteriorated after storage. Therefore, it was found that the addition of an alkoxysilane having a polyalkylene oxide chain in the preparation of the abrasive grains is necessary for the polishing defect characteristics and polishing properties of the chemical mechanical polishing composition.

[0162] From the above results, it was found that the chemical mechanical polishing composition of the present invention can suppress the occurrence of polishing defects when polishing a silicon oxide film, and can polish the silicon oxide film at high speed, and that the chemical mechanical polishing composition has excellent polishing properties after storage.

[0163] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations 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. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0164] 12...Slurry supply nozzle, 14...Slurry (chemical mechanical polishing composition), 16...Polishing pad, 18...Turntable, 20...Semiconductor substrate, 22...Carrier head, 24...Water supply nozzle, 26...Dresser, 100...Polishing apparatus

Claims

1. A method for manufacturing abrasive grains, comprising: A step (a) of heating a mixture containing particles having hydroxyl groups (—OH) immobilized on the surface thereof via covalent bonds and an alkoxysilane (A) having an epoxy group; a step (b) of adding a basic compound and heating the mixture after the step (a); a step (c) of adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture after the step (b); A method for producing abrasive grains, comprising:

2. A method for manufacturing abrasive grains, comprising: a step (d) of heating a mixture containing particles having hydroxyl groups (—OH) immobilized on the surface thereof via covalent bonds and an alkoxysilane (B) having an amino group; After the step (d), a step (e) of adding an alkoxysilane (C) having a polyalkylene oxide chain and heating the mixture; A method for producing abrasive grains, comprising:

3. The method for producing abrasive grains according to claim 1 or 2, wherein the particles are silica particles.

4. 3. The method for producing abrasive grains according to claim 1 or claim 2, wherein the polyalkylene oxide chain of the alkoxysilane (C) has at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2): -(CH ２ CH ２ O)- ・・・・(1) -(CHR １ CH ２ O)- ・・・・(2) (In the formula, R １ is C ｍ H ２ｍ＋１ where m is an integer of 1 to 4.

5. 2. The method for producing abrasive grains according to claim 1, wherein the basic compound is at least one selected from the group consisting of ammonia and compounds having an amino group.

6. 3. The method for producing abrasive grains according to claim 1, wherein the abrasive grains have, on their surfaces, at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4): -NR ２ R ３ ・・・・(3) -N ＋ R ２ R ３ R ４ M － ・・・・(4) (In the above formulas (3) and (4), R ２ , R ３ and R ４ Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － represents an anion.)

7. The method for producing abrasive grains according to claim 1, wherein the abrasive grains have a partial structure represented by the following general formula (5) on the surface thereof: 【Chemistry 1】 (In formula (5), R ５ represents a single bond or a divalent organic group having one or more carbon atoms, R ６ represents a divalent organic group having one or more carbon atoms, and R ７ , R ８ and R ９ are each independently a hydrogen atom or a carbon number represents one or more monovalent organic groups, and * represents a bond.

8. 3. The method for producing abrasive grains according to claim 1, wherein the abrasive grains have a partial structure represented by the following general formula (6) on the surface thereof: 【Chemistry 2】 (In formula (6), R １０ represents a divalent organic group having one or more carbon atoms, and R １１ and R １２ each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

9. The method for producing abrasive grains according to claim 1 or 2, wherein the abrasive grains have a zeta potential of 0 mV or more in a chemical mechanical polishing composition containing the abrasive grains.

10. Abrasive grains produced by the method of claim 1 or claim 2; A liquid medium; A chemical mechanical polishing composition comprising:

11. A chemical mechanical polishing composition comprising an abrasive grain and a liquid medium, a polymer chain is grafted to the surface of the abrasive grain by a covalent bond; The chemical mechanical polishing composition, wherein the abrasive grains have, on their surfaces, at least one partial structure selected from the group consisting of a partial structure represented by the following general formula (3) and a partial structure represented by the following general formula (4): -NR ２ R ３ ・・・・(3) -N ＋ R ２ R ３ R ４ M － ・・・・(4) (In the above formulas (3) and (4), R ２ , R ３ and R ４ Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － represents an anion.)

12. 12. The chemical mechanical polishing composition of claim 11, wherein the polymer chains covalently grafted to the surface of the abrasive grains are polyalkylene oxide chains.

13. A chemical mechanical polishing composition as described in claim 12, wherein the polyalkylene oxide chain covalently grafted to the surface of the abrasive grain has at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2): -(CH ２ CH ２ O)- ・・・・(1) -(CHR １ CH ２ O)- ・・・・(2) (In the formula, R １ is C ｍ H ２ｍ＋１ where m is an integer of 1 to 4.

14. The chemical mechanical polishing composition according to claim 13 , wherein the abrasive grains have a partial structure represented by the following general formula (5) on their surfaces: 【Transformation 3】 (In formula (5), R ５ represents a single bond or a divalent organic group having one or more carbon atoms, R ６ represents a divalent organic group having one or more carbon atoms, and R ７ , R ８ and R ９ each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

15. The chemical mechanical polishing composition according to claim 13 , wherein the abrasive grains have a partial structure represented by the following general formula (2) on the surface thereof: 【Chemistry 4】 (In formula (6), R １０ represents a divalent organic group having one or more carbon atoms, and R １１ and R １２ each independently represents a hydrogen atom or a monovalent organic group having one or more carbon atoms, and * represents a bond.

16. The chemical mechanical polishing composition according to claim 11 , having a pH of 2 or more and 6 or less.

17. The chemical mechanical polishing composition according to claim 11 , which is used to polish a silicon oxide film.

18. A polishing method comprising the step of polishing a silicon oxide film with the chemical mechanical polishing composition according to claim 11 .

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