Chemical mechanical polishing composition and polishing method

Abstract

To provide a chemical mechanical polishing composition with which a surface to be polished having a silicon oxide film can be polished at high speed, occurrence of surface defects after polishing can be reduced, and occurrence of foaming can be suppressed, and a polishing method using the same.SOLUTION: A chemical mechanical polishing composition according to the present invention contains (A) silica particles, (B) at least one selected from the group consisting of organic acid, nitric acid, sulfuric acid and phosphoric acid, and (C) a liquid medium. When, in the (A) silica particles, m (ppm) represents a content of an alkoxy group and n (nm) represents an average primary particle size, an m / n3 value is 0.1 or more, and the (A) silica particles include 15% or more of silica particles having a bent structure and / or a branched structure, of the number of particles observed in any visual field of a scanning electron microscope at 200,000 times magnification.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] With the advancement of semiconductor 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 (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 / 57155 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to further improve semiconductor productivity, there is a demand for a chemical mechanical polishing composition and a chemical mechanical polishing method that can polish a surface having a silicon oxide film, which is generally used as an insulating film, at high speed and that can reduce the occurrence of surface defects after polishing.

[0006] Furthermore, with the miniaturization of semiconductor wiring, even foaming during the delivery of the chemical mechanical polishing composition in a polishing machine can cause surface defects after polishing. Furthermore, in the production process of the chemical mechanical polishing composition, a waiting time is required until the foaming of the composition subsides. For these reasons, there is a demand for suppressing the occurrence of surface defects after polishing and improving the productivity of the chemical mechanical polishing composition by suppressing the occurrence of foaming in the chemical mechanical polishing composition.

[0007] Some aspects of the present invention provide a chemical mechanical polishing composition that can polish a surface having a silicon oxide film (hereinafter also referred to as "object to be polished") at high speed, reduce the occurrence of surface defects after polishing, and suppress the occurrence of foaming, as well as a polishing method using the same. [Means for solving the problem]

[0008] One aspect of the chemical mechanical polishing composition of the present invention is (A) silica particles; (B) at least one selected from the group consisting of organic acids, nitric acid, sulfuric acid, and phosphoric acid; (C) a liquid medium; A chemical mechanical polishing composition comprising: When the content of alkoxy groups in the (A) silica particles is m (ppm) and the average primary particle diameter is n (nm), m / n 3 The value is 0.1 or greater, The (A) silica particles contain 15% or more silica particles having a bent structure and / or a branched structure, based on the number of particles in an arbitrary field of view at 200,000 magnifications observed under a scanning electron microscope.

[0009] In one embodiment of the chemical mechanical polishing composition, The component (A) may contain 2000 mass ppm or more of alkoxy groups per 1 g of silica particles.

[0010] In any one of the embodiments of the chemical mechanical polishing composition, The true specific gravity of the component (A) is 1.95 g / cm3 It may be more than that.

[0011] In any one of the embodiments of the chemical mechanical polishing composition, The component (A) may contain 5 μmol or more of at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines per 1 g of silica particles.

[0012] In any one of the embodiments of the chemical mechanical polishing composition, When the content of the component (A) is MA [mass %] and the content of the component (B) is MB [mass %], MA / MB may be 0.1 to 600.

[0013] In any one of the embodiments of the chemical mechanical polishing composition, The component (B) may be a carboxylic acid or a salt of a carboxylic acid.

[0014] In any one of the embodiments of the chemical mechanical polishing composition, The pH may be 1 or more and 7 or less.

[0015] In any one of the embodiments of the chemical mechanical polishing composition, The component (A) may have at least one functional group selected from the functional groups represented by the following general formulas (1) to (4). -SO3 - M + ·····(1) -COO - M + ·····(2) (In the above formulas (1) and (2), M + represents a monovalent cation.) -NR 1 R 2 ·····(3) -N + R 1 R 2 R 3 M - ·····(4) (In the above formulas (3) and (4), R 1 , R2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0016] In any one of the embodiments of the chemical mechanical polishing composition, The component (A) may be silica particles having at least one functional group selected from the functional groups represented by the general formulae (1) to (4) fixed to the surface via a covalent bond.

[0017] In any one of the embodiments of the chemical mechanical polishing composition, The content of the component (A) may be 0.1% by mass or more and 20% by mass or less, based on 100% by mass of the chemical mechanical polishing composition.

[0018] One aspect of the polishing method according to the present invention is to The method includes polishing a semiconductor substrate using the chemical mechanical polishing composition of any one of the above embodiments. [Effects of the Invention]

[0019] The chemical mechanical polishing composition of the present invention can polish a surface having a silicon oxide film at high speed and reduce the occurrence of surface defects after polishing. Furthermore, the chemical mechanical polishing composition of the present invention can suppress the occurrence of foaming, thereby suppressing the occurrence of surface defects after polishing and improving the productivity of the composition. do. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view schematically showing a polishing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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 modifications are also included within the scope of the present invention.

[0022] In this specification, a numerical range described as "X to Y" is interpreted as including the numerical value X as the lower limit and the numerical value Y as the upper limit.

[0023] 1. Chemical mechanical polishing composition A chemical mechanical polishing composition according to one embodiment of the present invention contains (A) silica particles (also referred to herein as "component (A)"), (B) at least one selected from the group consisting of organic acids, nitric acid, sulfuric acid, and phosphoric acid (also referred to herein as "component (B)"), and (C) a liquid medium (also referred to herein as "component (C)").

[0024] Each component that can be contained in the chemical mechanical polishing composition according to this embodiment will be described in detail below.

[0025] 1.1.(A) Component The chemical mechanical polishing composition according to this embodiment contains (A) silica particles. The (A) silica particles have a ratio of m / n, where m (ppm) is the alkoxy group content of the (A) silica particles and n (nm) is the average primary particle diameter of the (A) silica particles. 3 The value is 0.1 or more, and 15% or more of the particles in an arbitrary field of view at 200,000 magnification observed under a scanning electron microscope contain silica particles with a bent structure and / or branched structure.

[0026] The content of (A) silica particles is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more, based on the total mass of the chemical mechanical polishing composition being 100% by mass. The content of (A) silica particles is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total mass of the chemical mechanical polishing composition being 100% by mass. When the content of (A) silica particles is within this range, the polishing rate can be sufficiently achieved while the occurrence of polishing scratches on the polished object can be more effectively reduced.

[0027] <m / n 3 Value> (A) Silica particles have a particle size distribution such that m (ppm) represents the content of alkoxy groups contained in the silica particles, and n (nm) represents the average primary particle size of the silica particles, and m / n 3 The value is 0.1 or more. 3 The value is preferably 0.2 or more, more preferably 0.3 or more. 3 The m / n value is preferably 4 or less, more preferably 3.5 or less. 3 When the value is within the above range, the polishing rate does not decrease and the occurrence of polishing scratches on the workpiece can be reduced.

[0028] Here, the content m (ppm) of alkoxy groups contained in the silica particles is a value measured by the following method. The silica particle dispersion is centrifuged at 215,000 G for 90 minutes, the supernatant is discarded, and the solid is vacuum dried at 60°C for 90 minutes. 0.5 g of the resulting dried product is weighed, placed in 50 mL of 1 M aqueous sodium hydroxide solution, and heated at 50°C for 24 hours while stirring. The dried product is dissolved by the above method. The resulting solution of the dried product is analyzed by gas chromatography to determine the alcohol content, which is taken as the alkoxy group content. A flame ionization detector (FID) is used as the detector for the gas chromatography. Gas chromatography analysis is performed in accordance with JIS K0114.

[0029] The content m (ppm) of alkoxy groups contained in the (A) silica particles is preferably 2000 mass ppm or more, more preferably 5000 mass ppm or more, per gram of silica particles. The content m (ppm) of alkoxy groups contained in the (A) silica particles is preferably 15000 mass ppm or less, more preferably 11000 mass ppm or less. When the content of alkoxy groups contained in the (A) silica particles is within the above range, the polishing performance of the silica particles is improved, and the occurrence of polishing scratches on the polished object may be reduced.

[0030] The average primary particle diameter n (nm) of the silica particles is a value measured and calculated by the following method. The silica particles are dried on a hot plate and then heat-treated at 800°C for 1 hour to prepare a measurement sample. The BET specific surface area is measured using the prepared measurement sample. The true specific gravity of the silica is 2.2 g / cm. 3 , 2727 / BET specific surface area (m 2 / g) is converted to the average primary particle diameter n (nm) of the silica particles.

[0031] The average primary particle diameter n of the (A) silica particles is preferably 5 nm or more, more preferably 10 nm or more. The average primary particle diameter n of the (A) silica particles is preferably 200 nm or less, more preferably 100 nm or less. When the average primary particle diameter n of the (A) silica particles is within the above range, it may be possible to reduce the occurrence of polishing scratches on the workpiece while maintaining a sufficient polishing rate.

[0032] (A) m / n of silica particles 3 The value is calculated by the following formula using the alkoxy group content m (ppm) and the average primary particle diameter n (nm). m / n 3 Value = (m [ppm]) / (n [nm]) 3

[0033] m / n 3 The values ​​are the following technical indicators. If silica particles are assumed to be spherical, the particle volume can be calculated using the average primary particle diameter n of the particles using the following formula: (4 / 3×π×(n / 2) 3 )=(π×n 3 ) / 6[nm 3 ] Next, if we divide the alkoxy group content m by the volume of the silica particle, which is assumed to be a perfect sphere, we get (m[ppm]) / ((π×n 3 ) / 6[nm 3 ])=(6 / π)×(m / n 3 )[ppm / nm 3 ] From this calculation formula, m / n 3 The value is proportional to the amount of alkoxy groups per unit volume of the silica particles, and is therefore an index of the amount of alkoxy groups per unit volume of the silica particles. For example, m / n 3 When comparing large and small values, m / n 3 A large value indicates that the amount of alkoxy groups per unit volume of silica particles is large. 3 When the alkoxy group content expressed by the value is 0.1 or more, the amount of alkoxy groups per unit volume of the silica particles is sufficiently large, so that the occurrence of polishing scratches on the polished object caused by the silica particles can be effectively reduced.

[0034] <Content of Silica Particles Having Bent and / or Branched Structures> The (A) silica particles contain 15% or more silica particles having a bent structure and / or a branched structure, based on the number of particles in an arbitrary field of view at 200,000 magnification when observed under a scanning electron microscope. The (A) silica particles preferably contain 20% or more silica particles having a bent structure and / or a branched structure. The (A) silica particles also preferably contain 40% or less, more preferably 35% or less, and particularly preferably 30% or less, silica particles having a bent structure and / or a branched structure. ( A) When the content ratio of silica particles having a bent structure and / or a branched structure of the silica particles is within the above range, the occurrence of polishing scratches on the polished object can be reduced without decreasing the polishing rate.

[0035] The content of silica particles having a bent structure and / or a branched structure can be calculated by the following measurement method. Particles with bent and / or branched structures are counted from the number of particles in an arbitrary field of view observed under a scanning electron microscope (SEM) at 200,000 magnification, and the percentage of such particles is calculated. A bent structure is a particle formed by three or more particles bonded in a line, not a straight line, and a branched structure is a particle formed by four or more particles bonded in a line, not a straight line (having branches).

[0036] <Average secondary particle diameter> The average secondary particle diameter of the (A) silica particles is preferably 8 nm or more, more preferably 15 nm or more. The average secondary particle diameter of the (A) silica particles is preferably 400 nm or less, more preferably 300 nm or less. When the average secondary particle diameter of the (A) silica particles is within the above range, the occurrence of polishing scratches on the polished object may be reduced without decreasing the polishing rate.

[0037] The average secondary particle size of the (A) silica particles can be measured by the following measurement method. Silica particles are added to a 0.3 wt% aqueous citric acid solution and homogenized to prepare a sample for measurement. The secondary particle diameter is measured using the dynamic light scattering method (manufactured by Otsuka Electronics Co., Ltd., model "ELSZ-2000S") using the obtained sample for measurement.

[0038] <association ratio> The association ratio of the (A) silica particles is a value obtained by calculating the average secondary particle size / average primary particle size of the (A) silica particles. The association ratio of the (A) silica particles is preferably 1.5 or more, more preferably 1.7 or more. The association ratio of the (A) silica particles is preferably 5.5 or less, more preferably 5.0 or less. When the association ratio of the (A) silica particles is within the above range, the occurrence of polishing scratches on the polished object may be reduced without decreasing the polishing rate.

[0039] <True specific gravity> (A) The true specific gravity of silica particles is 1.95 g / cm 3 More than 2.00 g / cm is preferable. 3 The true specific gravity of the (A) silica particles is more preferably 2.20 g / cm. 3 Preferably less than 2.18 g / cm 3 Less than 2.15 g / cm is more preferable. 3 The following is particularly preferred: (A) When the true specific gravity of the silica particles is within the above range, the occurrence of polishing scratches on the object to be polished may be reduced without decreasing the polishing rate.

[0040] The true specific gravity of the (A) silica particles can be calculated by the following measurement method. After drying the silica particles on a hot plate at 150°C, they are kept in a furnace at 300°C for 1 hour, and then the particle size can be measured by a liquid phase substitution method using ethanol.

[0041] <Amine content> The content of at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines in the (A) silica particles is preferably 5 μmol or more, more preferably 10 μmol or more, per gram of silica particles. The content of the amine in the (A) silica particles is preferably 100 μmol or less, more preferably 90 μmol or less, per gram of silica particles. When the amine content in the (A) silica particles is within this range, the content of silica particles having a bent structure and / or branched structure in the chemical mechanical polishing composition can be stably maintained at 15% or more, which may stabilize the polishing properties of the chemical mechanical polishing composition.

[0042] The content of at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines in the (A) silica particles can be measured by the following method. The silica particles were centrifuged at 215,000 G for 90 minutes, the supernatant was discarded, and the solids were vacuum dried at 60°C for 90 minutes. 0.5 g of the resulting dried silica was weighed and placed in 50 mL of 1 M aqueous sodium hydroxide. The silica was dissolved by heating at 50°C for 24 hours with stirring. The silica solution was analyzed by ion chromatography to determine the amine content. Ion chromatography analysis was performed in accordance with JIS K0127.

[0043] <Specific functional group> The (A) silica particles preferably have at least one functional group (also referred to herein as a "specific functional group") selected from the functional groups represented by the following general formulas (1) to (4). -SO3 - M + ·····(1) -COO - M + ·····(2) (In the above formulas (1) and (2), M + represents a monovalent cation.) -NR 1 R 2 ·····(3) -N + R 1 R 2 R 3 M - ·····(4) (In the above formulas (3) and (4), R 1 , R 2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0044] (A) silica particles at least partially modified with a specific functional group have a higher absolute zeta potential than (A) silica particles not surface-modified with a specific functional group, particularly in the pH range of 1 to 7, and the electrostatic repulsion between the (A) components is increased. As a result, the dispersion stability of the (A) component in the chemical mechanical polishing composition is improved, which may enable polishing while reducing the occurrence of polishing scratches on the polished object. Furthermore, foaming of the chemical mechanical polishing composition during the production process or when delivered to a polishing machine may be effectively suppressed. As a result, the waiting time until foaming of the composition subsides is shortened, improving the productivity of the composition and effectively suppressing the occurrence of polishing defects caused by foaming when the polishing machine delivers the composition to the polished object.

[0045] Furthermore, silica particles are susceptible to reaction with water, oxygen, nitrogen, etc., and tend to deteriorate over time. However, (A) silica particles, at least a portion of whose surface is modified with a specific functional group, may be able to suppress deterioration by reducing the reactivity of water, oxygen, nitrogen, etc. on the particle surface due to the specific functional group.

[0046] (Functional group represented by general formula (1)) The component (A) preferably has a functional group represented by the following general formula (1) on at least a portion of its surface. -SO3 - M + ·····(1) (M + represents a monovalent cation.)

[0047] In the above formula (1), M + Examples of monovalent cations represented by the formula include, but are not limited to, H + , Li + , Na + , K. + , NH4 +In other words, the functional group represented by the general formula (1) can be rephrased as "at least one functional group selected from the group consisting of sulfo groups and salts thereof." Here, the "salt of a sulfo group" refers to a functional group in which the hydrogen ion contained in the sulfo group (-SO3H) is converted into Li + , Na + , K. + , NH4 + Here, "component (A) having a functional group represented by general formula (1)" refers to a component having a functional group represented by general formula (1) fixed to its surface via a covalent bond, and a compound having a functional group represented by general formula (1) is physically present on its surface. It does not include ionically adsorbed substances.

[0048] Component (A) having a functional group represented by general formula (1) can be produced, for example, by applying the method described in JP 2010-269985 A. Specifically, silica and a mercapto group-containing silane coupling agent are thoroughly stirred in an acidic medium to covalently bond the mercapto group-containing silane coupling agent to the surface of the silica. Examples of mercapto group-containing silane coupling agents include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Next, an appropriate amount of hydrogen peroxide is further added and the mixture is allowed to stand for a sufficient period to obtain component (A) having a functional group represented by general formula (1).

[0049] The zeta potential of component (A) having a functional group represented by general formula (1) is negative in the chemical mechanical polishing composition, and this negative potential is preferably -10 mV or less, more preferably -20 mV or less. When the zeta potential of component (A) having a functional group represented by general formula (1) is within the above range, the electrostatic repulsion between particles effectively prevents particle aggregation, and in some cases, it is possible to selectively polish a positively charged substrate during chemical mechanical polishing. Zeta potential measuring devices include the "ELSZ-1" manufactured by Otsuka Electronics Co., Ltd. and the "Zetasizer Nano ZS" manufactured by Malvern. The zeta potential of component (A) having a functional group represented by general formula (1) can be adjusted by appropriately increasing or decreasing the amount of the mercapto group-containing silane coupling agent or the like added.

[0050] When the chemical mechanical polishing composition according to this embodiment contains component (A) having a functional group represented by general formula (1), the content of component (A) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more, based on the total mass of the chemical mechanical polishing composition being 100% by mass. The content of component (A) is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total mass of the chemical mechanical polishing composition being 100% by mass. When the content of component (A) having a functional group represented by general formula (1) is within the above range, the occurrence of polishing scratches on the polished object can be more effectively reduced, and the storage stability of the chemical mechanical polishing composition may be improved.

[0051] (Functional group represented by general formula (2)) The component (A) preferably has a functional group represented by the following general formula (2) on at least a portion of its surface. -COO - M + ·····(2) (M + represents a monovalent cation.)

[0052] In the above formula (2), M +Examples of monovalent cations represented by the formula include, but are not limited to, H + , Li + , Na + , K. + , NH4 + In other words, the functional group represented by the general formula (2) can be rephrased as "at least one functional group selected from the group consisting of a carboxy group and a salt thereof." Here, the "salt of a carboxy group" refers to a functional group in which the hydrogen ion contained in the carboxy group (-COOH) is converted to Li. + , Na + , K. + , NH4 + Here, "component (A) having a functional group represented by general formula (2)" refers to a component having a functional group represented by general formula (2) fixed to its surface via a covalent bond, and does not include a component having a compound having a functional group represented by general formula (2) physically or ionically adsorbed to its surface.

[0053] The component (A) having a functional group represented by general formula (2) can be produced by applying the method described in JP-A-2010-105896, for example. Specifically, silica and a carboxylic acid anhydride-containing silane coupling agent are mixed with water, methanol, and ammonia to produce a silane coupling agent. The resulting mixture is thoroughly stirred in a basic medium to covalently bond the carboxylic acid anhydride silane coupling agent to the surface of the silica, and the modified carboxylic acid anhydride is then hydrolyzed to undergo a ring-opening reaction to form a dicarboxylic acid, thereby obtaining component (A) having a functional group represented by general formula (2). Examples of carboxylic acid anhydride-containing silane coupling agents include 3-(triethoxysilyl)propylsuccinic anhydride.

[0054] The zeta potential of component (A) having a functional group represented by general formula (2) is negative in the chemical mechanical polishing composition, and this negative potential is preferably -10 mV or less, more preferably -12 mV or less. When the zeta potential of component (A) having a functional group represented by general formula (2) is within the above range, the electrostatic repulsion between particles effectively prevents particle aggregation, and may enable selective polishing of a positively charged substrate during chemical mechanical polishing. The zeta potential measuring device described above can be used. The zeta potential of component (A) having a functional group represented by general formula (2) can be adjusted by appropriately increasing or decreasing the amount of the carboxylic acid anhydride-containing silane coupling agent or the like added.

[0055] When the chemical mechanical polishing composition according to this embodiment contains component (A) having a functional group represented by general formula (2), the content of component (A) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more, based on the total mass of the chemical mechanical polishing composition being 100% by mass. The content of component (A) is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total mass of the chemical mechanical polishing composition being 100% by mass. When the content of component (A) having a functional group represented by general formula (2) is within the above range, the occurrence of polishing scratches on the polished object can be more effectively reduced, and the storage stability of the chemical mechanical polishing composition may be improved.

[0056] (Functional group represented by general formula (3)) The component (A) preferably has functional groups represented by the following general formula (3) and / or the following general formula (4) on at least a portion of the surface. -NR 1 R 2 ·····(3) -N + R 1 R 2 R 3 M - ·····(4) (In the above formula (3) and the above formula (4), R 1 , R2 and R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. - represents an anion.)

[0057] The functional group represented by general formula (3) represents an amino group, and the functional group represented by general formula (4) represents a salt of an amino group. Therefore, the functional group represented by general formula (3) and the functional group represented by general formula (4) can be collectively referred to as "at least one functional group selected from the group consisting of amino groups and their salts." Here, "component (A) having functional groups represented by general formula (3) and / or general formula (4)" refers to a component having functional groups represented by general formula (3) and / or general formula (4) immobilized on its surface via a covalent bond, but does not include a component having a compound having functional groups represented by general formula (3) and / or general formula (4) physically or ionically adsorbed on its surface.

[0058] 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.

[0059] In the above formula (3) and the above formula (4), R 1 ~R 3 Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group, and R 1 ~R 3 Two or more of these may be bonded to form a ring structure.

[0060] R 1 ~R 3The 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, or cyclic alkyl groups, alkenyl groups, aralkyl groups, and aryl groups.

[0061] 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.

[0062] 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.

[0063] The aralkyl group preferably has a carbon number of 7 to 12. Examples of such an aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a phenylhexyl group, a methylbenzyl group, a methylphenethyl group, and an ethylbenzyl group.

[0064] 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.

[0065] The aromatic rings of the above aryl and aralkyl 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.

[0066] Component (A) having functional groups represented by general formula (3) and / or general formula (4) can be produced, for example, by applying the method described in JP 2005-162533 A. Specifically, component (A) having functional groups represented by general formula (3) and / or general formula (4) can be obtained by thoroughly stirring silica and an amino group-containing silane coupling agent in an acidic medium to covalently bond the amino group-containing silane coupling agent to the surface of component (A). Examples of amino group-containing silane coupling agents include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0067] The zeta potential of component (A) having functional groups represented by general formula (3) and / or general formula (4) is positive in the chemical mechanical polishing composition, preferably +10 mV or higher, more preferably +15 mV or higher. When the zeta potential of component (A) having functional groups represented by general formula (3) and / or general formula (4) is within the above range, the electrostatic repulsion between particles effectively prevents particle aggregation, and may enable selective polishing of negatively charged substrates during chemical mechanical polishing. The zeta potential measuring device described above can be used. The zeta potential of component (A) having functional groups represented by general formula (3) and / or general formula (4) can be adjusted by appropriately increasing or decreasing the amount of the amino group-containing silane coupling agent or the like added.

[0068] When the chemical mechanical polishing composition according to this embodiment contains component (A) having functional groups represented by general formula (3) and / or general formula (4), the content of component (A) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more, based on the total mass of the chemical mechanical polishing composition taken as 100% by mass. The content of component (A) is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total mass of the chemical mechanical polishing composition taken as 100% by mass. When the content of component (A) having functional groups represented by general formula (3) and / or general formula (4) is within the above range, the occurrence of polishing scratches on the polished object can be reduced, and the storage stability of the chemical mechanical polishing composition may be improved.

[0069] 1.2.(B) Component The chemical mechanical polishing composition according to this embodiment contains (B) at least one selected from the group consisting of organic acids, nitric acid, sulfuric acid, and phosphoric acid. The inclusion of component (B) can suppress foaming of the composition during the production process of the chemical mechanical polishing composition or when the composition is delivered to a polishing machine. As a result, the productivity of the composition is improved by shortening the waiting time until foaming of the composition subsides, and polishing defects caused by foaming during delivery to a workpiece in a polishing machine can be effectively suppressed.

[0070] Among organic acids, preferred are compounds having a carboxy group and compounds having a sulfo group.Examples of compounds having a carboxy group include stearic acid, lauric acid, oleic acid, myristic acid, alkenyl succinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, formic acid, acetic acid, oxalic acid, citric acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinolinic acid, quinaldic acid, propionic acid, adipic acid, pyromellitic acid, trifluoroacetic acid; amino acids such as glycine, alanine, aspartic acid, glutamic acid, lysine, arginine, tryptophan, dodecylaminoethylaminoethylglycine, aromatic amino acids, heterocyclic amino acids; imino acids such as alkyliminodicarboxylic acids; and salts thereof.In addition, compounds having a carboxy group may be polymer compounds, such as polyacrylic acid or its salts. Examples of compounds having a sulfo group include amidosulfuric acid; alkylbenzenesulfonic acids such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid; alkylnaphthalenesulfonic acids such as butylnaphthalenesulfonic acid; α-olefinsulfonic acids such as tetradecenesulfonic acid; polystyrenesulfonic acid; and salts thereof. Among these, compounds having a carboxy group are preferred, and carboxylic acids or salts of carboxylic acids are more preferred, with monocarboxylic acids, dicarboxylic acids, or salts of these being particularly preferred. These (B) components may be used alone or in combination of two or more.

[0071] The content of component (B), when the total mass of the chemical mechanical polishing composition is taken as 100 mass%, is preferably 0.001 mass% or more, more preferably 0.005 mass% or more, and particularly preferably 0.01 mass% or more. The content of component (B), when the total mass of the chemical mechanical polishing composition is taken as 100 mass%, is preferably 1 mass% or less, more preferably 0.8 mass% or less, and particularly preferably 0.5 mass% or less. When the content of component (B) is within the above range, foaming of the chemical mechanical polishing composition during the production process or when the composition is delivered to a polishing machine can be effectively suppressed.

[0072] In the chemical mechanical polishing composition according to this embodiment, when the content of the component (A) is MA [mass %] and the content of the component (B) is MB [mass %], the ratio MA / MB is preferably 0.1 or more, more preferably 0.2 or more. The ratio MA / MB is preferably 600 or less, more preferably 500 or less, and particularly preferably 400 or less. When the ratio MA / MB is within the above range, both a high polishing rate for the workpiece and suppression of polishing scratches can be achieved. This makes it easier to produce the chemical mechanical polishing composition, and shortens the waiting time until the foaming subsides when producing the chemical mechanical polishing composition, thereby improving the productivity of the chemical mechanical polishing composition.

[0073] 1.3.(C) Liquid Media The chemical mechanical polishing composition according to this embodiment contains a liquid medium (C). Examples of component (C) include water, a mixed medium of water and alcohol, and a mixed medium containing water and an organic solvent compatible with water. Among these, water or a mixed medium of water and alcohol is preferred, and water is more preferred. While the water is not particularly limited, pure water is preferred. Water may be blended as the remainder of the constituent materials of the chemical mechanical polishing composition, and there are no particular limitations on the amount of water.

[0074] 1.4.Other Ingredients In addition to the components described above, the chemical mechanical polishing composition of this embodiment may contain, as necessary, an oxidizing agent, a nitrogen-containing heterocyclic compound, a water-soluble polymer, a surfactant, an inorganic acid and its salt, a basic compound, etc.

[0075] <Oxidizing agent> The chemical mechanical polishing composition according to this embodiment may contain an oxidizing agent, which oxidizes the polishing target and promotes a complexing reaction with the polishing liquid components, thereby creating a brittle modified layer on the polishing target, thereby facilitating polishing.

[0076] Examples of oxidizing agents include ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, 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 particularly preferred, in consideration of oxidizing power and ease of handling. These oxidizing agents may be used alone or in combination of two or more.

[0077] The content of the oxidizing agent is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, based on the total mass of the chemical mechanical polishing composition, and is preferably 5% by mass or less, more preferably 3% by mass or less, based on the total mass of the chemical mechanical polishing composition, based on 100% by mass.

[0078] <Nitrogen-containing heterocyclic compounds> The chemical mechanical polishing composition according to this embodiment may contain a nitrogen-containing heterocyclic compound. By containing the nitrogen-containing heterocyclic compound, the surface of the object to be polished is protected by the nitrogen-containing heterocyclic compound, which may reduce the occurrence of polishing defects in the object to be polished.

[0079] Nitrogen-containing heterocyclic compounds are organic compounds containing at least one nitrogen atom and at least one heterocyclic ring selected from five-membered heterocyclic rings and six-membered heterocyclic rings. Specific examples of heterocyclic rings include five-membered heterocyclic rings such as pyrrole structure, imidazole structure, triazole structure, and thiazoline structure; and six-membered heterocyclic rings such as pyridine structure, pyrimidine structure, pyridazine structure, and pyrazine structure. The heterocyclic ring may form a condensed ring. Specific examples include an indole structure, an isoindole structure, a benzimidazole structure, a benzotriazole structure, an isothiazolin structure, a quinoline structure, an isoquinoline structure, a quinazoline structure, a cinnoline structure, a phthalazine structure, a quinoxaline structure, and an acridine structure. Among heterocyclic compounds having such structures, heterocyclic compounds having a pyridine structure, a quinoline structure, a benzimidazole structure, a benzotriazole structure, or an isothiazolin structure are preferred.

[0080] Specific examples of nitrogen-containing heterocyclic compounds include aziridine, pyridine, pyrimidine, and pyrrolidine. Examples of the nitrogen-containing heterocyclic compound include benzotriazole, 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.

[0081] <Water-soluble polymer> The chemical mechanical polishing composition according to this embodiment may contain a water-soluble polymer. By containing a water-soluble polymer, the water-soluble polymer may be adsorbed onto the surface of the workpiece to be polished, thereby reducing polishing friction and possibly reducing the occurrence of polishing scratches on the workpiece.

[0082] Examples of the water-soluble polymer include water-soluble polymers different from the polymer compound corresponding to component (B), such as polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyallylamine, and hydroxyethyl cellulose.

[0083] The weight-average molecular weight (Mw) of the water-soluble polymer is preferably from 10,000 to 1.5 million, more preferably from 40,000 to 1.2 million. Here, the "weight-average molecular weight" refers to the weight-average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography).

[0084] <Surfactant> The chemical mechanical polishing composition according to this embodiment may contain a surfactant. The surfactant is not particularly limited, and examples thereof include anionic surfactants, cationic surfactants, and nonionic surfactants. Examples of anionic surfactants include sulfates such as alkyl ether sulfates and polyoxyethylene alkylphenyl ether sulfates; and fluorine-containing surfactants such as perfluoroalkyl compounds. Examples of cationic surfactants include aliphatic amine salts and aliphatic ammonium salts. Examples of nonionic surfactants include nonionic surfactants having 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.

[0085] <Inorganic acids and their salts> The inorganic acid may be an inorganic acid different from component (B), such as hydrochloric acid. The inorganic acid may form a salt with a base added separately to the chemical mechanical polishing composition.

[0086] <Basic compounds> Examples of basic compounds include organic bases and inorganic bases. Preferred organic bases include amines, such as triethylamine, monoethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, benzylamine, methylamine, ethylenediamine, diglycolamine, and isopropylamine. Examples of inorganic bases include ammonia, potassium hydroxide, and sodium hydroxide. Among these basic compounds, ammonia and potassium hydroxide are preferred. These basic compounds may be used alone or in combination of two or more.

[0087] 1.5.pH The pH of the chemical mechanical polishing composition according to this embodiment is preferably from 1 to 7, more preferably from 2 to 6, and particularly preferably from 2.5 to 5.5. When the pH is within this range, the absolute value of the zeta potential of component (A) in the chemical mechanical polishing composition increases, improving dispersibility. This may enable the workpiece to be polished at high speed and reduce the occurrence of polishing defects in the workpiece.

[0088] The pH of the chemical mechanical polishing composition according to this embodiment can be adjusted as needed by appropriately increasing or decreasing the content of the component (B), the inorganic acid and its salt, and the basic compound.

[0089] In the present invention, pH refers to hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, a tabletop pH meter manufactured by Horiba, Ltd.) under conditions of 25°C and 1 atmosphere.

[0090] 1.6.Applications The chemical mechanical polishing composition according to this embodiment is suitable as a polishing material for chemical mechanical polishing of a semiconductor substrate having multiple materials constituting a semiconductor device. The semiconductor substrate may contain, for example, a conductive metal such as copper, tungsten, cobalt, ruthenium, or molybdenum, an insulating film material such as silicon oxide, silicon nitride, or amorphous silicon, or a barrier metal material such as titanium, titanium nitride, or tantalum nitride.

[0091] The polishing target of the chemical mechanical polishing composition of this embodiment is particularly preferably a semiconductor substrate having a portion containing a silicon oxide film. Specific examples of such semiconductor substrates include semiconductor substrates on which a silicon oxide film is formed. The chemical mechanical polishing composition of this embodiment enables high-speed polishing of such semiconductor substrates and effectively suppresses the occurrence of polishing scratches.

[0092] 1.7. 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.

[0093] 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.

[0094] 2. Polishing method A polishing method according to one embodiment of the present invention includes polishing a semiconductor substrate using the chemical mechanical polishing composition described above. This chemical mechanical polishing composition allows for high-speed polishing of a surface having a silicon oxide film, while reducing the occurrence of surface defects such as polishing scratches after polishing. Therefore, the polishing method according to this embodiment is particularly suitable for polishing a semiconductor substrate having a silicon oxide film formed thereon.

[0095] 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 polished by moving the surface to be polished and the polishing pad relative to each other. A common chemical mechanical polishing apparatus having a holder for holding the semiconductor substrate and a polishing table to which a polishing pad is attached can be used. Common nonwoven fabrics, polyurethane foams, porous fluororesins, etc. can be used as the polishing pad. During polishing, the chemical mechanical polishing composition is applied to the polishing pad. is continuously supplied by 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 always covered with the abrasive. After polishing, the semiconductor substrate is preferably thoroughly washed with running water, and then dried using a spin dryer or the like to remove water droplets adhering to the semiconductor substrate.

[0096] The polishing method according to this embodiment can be used, for example, in trench isolation (STI). In trench isolation, it is necessary to remove the silicon oxide film by CMP to expose the silicon nitride film, and the polishing method according to this embodiment can be suitably used to polish this silicon oxide film.

[0097] The above-described polishing step can be performed using a polishing apparatus 100 as 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.

[0098] 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.

[0099] 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 LK"; and G&P Technology models "POLI-400L" and "POLI-762."

[0100] 3. Working Example The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In these examples, "parts" and "%" are by mass unless otherwise specified.

[0101] 3.1.Preparation of abrasive grains <Abrasive grain A> A flask was charged with 7,500 g of pure water as a solvent and 1.93 g of 3-ethoxypropylamine as an alkali catalyst to prepare a mother liquid. The mother liquid was heated to an internal temperature of 85°C, and then 2,740 g of tetramethyl orthosilicate was added dropwise at a constant rate over 60 minutes while controlling the temperature to prevent fluctuations in the internal temperature, to prepare a mixed liquid. 2,452 g of seed particle dispersion and 5,537 g of pure water were added to the flask. The mixture was then heated to an internal temperature of 80°C, and 1,762.7 g of tetramethyl orthosilicate was added dropwise at a constant rate over 360 minutes while controlling the temperature to prevent fluctuations in the internal temperature. After the addition, the mixture was stirred for 15 minutes to prepare a liquid containing irregularly shaped silica. Next, 800 mL of the liquid containing irregularly shaped silica was sampled as a base amount under atmospheric pressure, and colloidal silica was added while maintaining the volume constant. The mixture was then heated and concentrated until the silica concentration reached 20% by mass. Next, in order to distill off methanol produced as a by-product during the reaction, the dispersion medium was replaced with 500 mL of pure water while keeping the volume constant, to prepare a dispersion containing abrasive grains A.

[0102] <Abrasive B> A flask was charged with 7,500 g of pure water as a solvent and 0.580 g of 3-ethoxypropylamine as an alkali catalyst to prepare a mother liquid. After heating the mother liquid to an internal temperature of 85°C, 2,740 g of tetramethyl orthosilicate was added dropwise at a constant rate over 120 minutes while controlling the temperature to prevent fluctuations in the internal temperature, thereby preparing a mixed liquid. After stirring for 420 minutes, 50.12 g of 3-ethoxypropylamine was added to the mixed liquid to prepare a seed particle dispersion. 2,331 g of the seed particle dispersion and 5,265 g of pure water were charged into a flask. The flask was then heated to an internal temperature of 80°C, and 1,957 g of tetramethyl orthosilicate was added dropwise at a constant rate over 360 minutes while controlling the temperature to prevent fluctuations in the internal temperature. After the addition, the mixture was stirred for 15 minutes to prepare a liquid containing irregularly shaped silica. Next, 800 mL of the liquid containing irregularly shaped silica was taken as a base volume under normal pressure, and colloidal silica was fed while maintaining the volume constant, and the liquid was heated and concentrated until the silica concentration reached 20 mass%. Next, in order to distill off the methanol by-product during the reaction, the dispersion medium was replaced with 500 mL of pure water while maintaining the volume constant, to prepare a dispersion containing abrasive grains B.

[0103] <Abrasive Grain C> A mother liquor was prepared by adding 7,500 g of pure water as a solvent to a flask and 0.774 g of 3-ethoxypropylamine as an alkali catalyst. After heating the mother liquor to an internal temperature of 85°C, 2,740 g of tetramethyl orthosilicate was added dropwise over 60 minutes at a constant rate while maintaining the internal temperature constant. This resulted in a mixed solution. After 60 minutes of stirring, 28.00 g of 3-ethoxypropylamine was added to the mixed solution to prepare a seed particle dispersion. Next, 800 mL of the seed particle dispersion was taken as a base volume under atmospheric pressure. While maintaining the volume constant, colloidal silica was added and the mixture was heated and concentrated until the silica concentration reached 20% by mass. Next, to distill off the methanol by-product during the reaction, 400 mL of pure water was added as the dispersion medium, while maintaining the volume constant, to prepare a dispersion containing abrasive grains C.

[0104] <Abrasive grain D> A mother liquor was prepared by adding 7,500 g of pure water as a solvent to a flask and adding 1.328 g of dipropylamine as an alkaline catalyst. After heating the mother liquor to an internal temperature of 85°C, 2,740 g of tetramethyl orthosilicate was added dropwise to the mother liquor at a constant rate over 60 minutes while controlling the temperature to prevent fluctuations in the internal temperature. After 15 minutes of stirring, 49.18 g of dipropylamine was added to the mixture to prepare a seed particle dispersion. Next, 800 mL of the seed particle dispersion was taken as the base volume under atmospheric pressure. While maintaining the volume constant, the dispersion medium was replaced with 1,400 mL of pure water to distill off the methanol by-product generated during the reaction. This produced a dispersion containing abrasive grain D.

[0105] <Abrasive Grain E> A mother liquor was prepared by adding 7,500 g of pure water as a solvent to a flask and adding 1.328 g of triethylamine as an alkaline catalyst. After heating the mother liquor to an internal temperature of 85°C, 2,740 g of tetramethyl orthosilicate was added dropwise to the mother liquor at a constant rate over 60 minutes while controlling the temperature to prevent fluctuations in the internal temperature. After 15 minutes of stirring, 49.18 g of triethylamine was added to the mixture to prepare a seed particle dispersion. Next, 800 mL of the seed particle dispersion was sampled as the base volume under atmospheric pressure. Next, the dispersion medium was replaced with 650 mL of pure water while maintaining the volume constant to distill off the methanol by-product during the reaction. This produced a dispersion containing abrasive grain E.

[0106] <Abrasive Grain F> A mother liquor was prepared by adding 0.151 g of a 25% aqueous solution of tetramethylammonium hydroxide to 1732 g of water and stirring, and then heated to reflux. Tetramethyl orthosilicate was hydrolyzed to prepare a 9% aqueous solution of silicic acid. Under reflux, 346.5 g of an aqueous solution of silicic acid was added dropwise to the mother liquor over a period of 3 hours, and the mixture was refluxed for 30 minutes. Next, 1.26 g of a 25% aqueous solution of tetramethylammonium hydroxide was added dropwise to prepare a seed particle dispersion. The seed particle dispersion was then heated to reflux. 2910 g of water was added, stirred, and heated to reflux. Next, 500 g of a 9% aqueous silicic acid solution and 1.21 g of a 25% aqueous tetramethylammonium hydroxide solution were added dropwise over 2.5 hours, while 600 g of the water and methanol mixture was extracted. This operation was repeated 26 times, and then the mixture was heated and concentrated until the silica concentration reached 20% by mass. This produced a dispersion containing abrasive grains F.

[0107] <Abrasive G> A mother liquor was prepared by adding 0.365 g of a 25% aqueous solution of tetramethylammonium hydroxide to 2000 g of water and stirring, and then heated to 80°C. While maintaining the temperature of the mother liquor at 80°C, 228 g of tetramethyl orthosilicate was added dropwise over 3 hours. Immediately after, 2.92 g of a 25% aqueous solution of tetramethylammonium hydroxide was added. While maintaining the temperature at 80°C, 228 g of tetramethyl orthosilicate and 3.19 g of a 25% aqueous solution of tetramethylammonium hydroxide were added dropwise over 3 hours. This operation was repeated four times, and the mixture was then heated and concentrated until the silica concentration reached 20% by mass. This resulted in the preparation of a dispersion containing abrasive grain G.

[0108] <Abrasive grain H> 0.60 g of 3-aminopropyltrimethoxysilane was added to 300 g of an aqueous dispersion of abrasive grain A with a silica concentration of 20% by mass, and the mixture was refluxed at boiling point for 4 hours. Then, pure water was added to maintain the volume of the dispersion, and the by-product methanol was distilled off by heating. The dispersion was left to cool to below 30°C, and an aqueous dispersion containing abrasive grain H, in which the surface of abrasive grain A had been modified with amino groups, was prepared.

[0109] <Abrasive grain I> 1.38 g of 3-mercaptopropyltrimethoxysilane was added to 300 g of an aqueous dispersion of abrasive grain B with a silica concentration of 20% by mass, and the mixture was refluxed at the boiling point for 6 hours. Subsequently, pure water was added to maintain the volume of the dispersion, and the by-product methanol was distilled off by heating. The dispersion was then allowed to cool to below 30°C, after which 5 g of 30% hydrogen peroxide was added, and the dispersion was allowed to react for an additional 6 hours while maintaining the temperature at approximately 70°C. After the reaction was complete, the dispersion was allowed to cool to below 30°C, yielding an aqueous dispersion containing abrasive grain I, in which the surface of abrasive grain B had been modified with sulfo groups.

[0110] <Abrasive grain J> 0.36 g of 3-(glycidyloxypropyl)trimethoxysilane was added to 300 g of an aqueous dispersion of abrasive grain C with a silica concentration of 20% by mass and stirred at room temperature for 4 hours. Next, 5 g of 29% aqueous ammonia was added, and the dispersion was further reacted for 6 hours while maintaining the temperature at approximately 70°C. This procedure introduced amino groups derived from the amino alcohol moieties onto the silica surface. Subsequently, pure water was added to maintain the volume of the dispersion, and the by-product methanol and added ammonia were distilled off by heating. This procedure was terminated when the pH of the dispersion reached 8.5 or below. After completion, the dispersion was left to cool to 30°C or below, and an aqueous dispersion containing abrasive grain J in which the surface of abrasive grain C was modified with amino groups was prepared.

[0111] <Abrasive grain K> 0.09 g of 3-mercaptopropyltrimethoxysilane was added to 300 g of an aqueous dispersion of abrasive grain D with a silica concentration of 10% by mass, and the mixture was refluxed at the boiling point for 6 hours. Subsequently, pure water was added to maintain the volume of the dispersion, and the by-product methanol was distilled off by heating. The dispersion was then allowed to cool to below 30°C, after which 2 g of 30% hydrogen peroxide was added, and the dispersion was allowed to react for an additional 6 hours while maintaining the temperature at approximately 70°C. After the reaction was complete, the dispersion was allowed to cool to below 30°C, yielding an aqueous dispersion containing abrasive grain K, in which the surface of abrasive grain D had been modified with sulfo groups.

[0112] <Abrasive grain L> 30 g of 29% aqueous ammonia was added to 300 g of an aqueous dispersion of abrasive grain E with a silica concentration of 10 mass %. 0.84 g of 3-(triethoxysilyl)propylsuccinic anhydride was added to this dispersion. The mixture was added to a 1000 ml solution of 1000 ml of ammonia and refluxed at the boiling point for 6 hours. Pure water was then added to maintain the volume of the dispersion, replacing the ammonia and by-product methanol with water. This process was completed when the pH of the dispersion reached 8.5 or less. The dispersion was left to cool to 30°C or less, yielding an aqueous dispersion containing abrasive grains L, the surface of which had been modified with carboxyl groups.

[0113] 3.2.Method for evaluating the physical properties of abrasive grains The physical properties of the abrasive grains A to L prepared above were measured by the following methods, and the results are shown in Table 1 below.

[0114] [Table 1]

[0115] The raw materials used to prepare the abrasive grains and the abbreviations listed in Table 1 above are the following products or reagents. 3-Ethoxypropylamine: abbreviated as "3-EOPA" in the table, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. , product name "3-ethoxypropylamine" Tetramethyl orthosilicate: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Tetramethyl orthosilicate" Dipropylamine: abbreviated as "DPA" in the table, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Dipropylamine" Triethylamine: abbreviated as "TEA" in the table, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "triethylamine" 25% tetramethylammonium hydroxide: abbreviated as "TMAH" in the table, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "25% tetramethylammonium hydroxide solution," component concentration 25% 3-aminopropyltrimethoxysilane: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "3-aminopropyltrimethoxysilane" 3-Mercaptopropyltrimethoxysilane: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "(3-mercaptopropyl)trimethoxysilane" 30% hydrogen peroxide: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Hydrogen Peroxide," concentration 30% 3-(Glycidyloxypropyl)trimethoxysilane: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "3-glycidyloxypropyltrimethoxysilane" 29% Ammonia Water: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Ammonia Water", ingredient concentration 29% 3-(Triethoxysilyl)propyl succinic anhydride: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "(3-triethoxysilyl)propyl]succinic anhydride"

[0116] <Average primary particle diameter n (nm)> The aqueous dispersion of abrasive grains prepared above was pre-dried on a hot plate and then heat-treated at 800°C for 1 hour to obtain a measurement sample. The BET specific surface area was measured using the obtained measurement sample. The measurement was performed using a "micrometrics FlowSorb II 2300" manufactured by Shimadzu Corporation. The true specific gravity of the silica abrasive grains was 2.2 g / cm. 3 , 2727 / BET specific surface area (m 2 / g) was converted to calculate the average primary particle diameter n (nm) of the abrasive grains in the dispersion.

[0117] <Average secondary particle diameter (nm)> The measurement sample for dynamic light scattering was prepared with an abrasive grain concentration of 1%, a citric acid concentration of 0.3%, and the remainder water. Using the obtained measurement sample, the average secondary particle diameter was measured by dynamic light scattering (Otsuka Electronics Co., Ltd., particle size / molecular weight measurement system "ELSZ-2000S").

[0118] <association ratio> The value calculated by dividing the average secondary particle size by the average primary particle size was taken as the association ratio.

[0119] <Bent and branched particle content (%)> The abrasive grains prepared above were observed under a scanning electron microscope (Hitachi High-Technologies Corporation, Model S-5200) at 200,000 magnification, and the number of particles with bent and branched structures was counted within an arbitrary field of view, and the percentage of such particles was calculated. This procedure was repeated 50 times, and the average value was taken as the bent / branched particle content (%). A bent structure is a particle formed by three or more particles joined in a line, not a straight line, and a branched structure is a particle formed by four or more particles joined in a line, not a straight line (having branches).

[0120] <True specific gravity (g / cm 3 )> The true specific gravity of each abrasive grain was evaluated according to the method described in Example 14 of WO 2015 / 200678.

[0121] <Amine content (μmol / g)> The aqueous dispersion of abrasive grains prepared above was centrifuged at 215,000 G for 90 minutes, after which the supernatant was discarded and the solids were vacuum dried at 60°C for 90 minutes. 0.5 g of the resulting dried silica was weighed and placed in 50 mL of 1 M aqueous sodium hydroxide solution. The silica was dissolved by heating at 50°C for 24 hours with stirring. The silica solution was analyzed using an ion chromatograph (Nippon Dionex, Model "ICS-2100") to determine the amine content per gram of silica. The ion chromatographic analysis was performed in accordance with JIS K0127.

[0122] <Alkoxy group content m (ppm)> The aqueous dispersion of abrasive grains prepared above was centrifuged at 215,000 G for 90 minutes, after which the supernatant was discarded and the solids were vacuum dried at 60°C for 90 minutes. 0.5 g of the resulting dried silica was weighed and placed in 50 mL of 1 M aqueous sodium hydroxide solution. The silica was dissolved by stirring and heating at 50°C for 24 hours. The silica solution was analyzed using a gas chromatograph (Shimadzu Corporation, model "Shimadzu GC-14A") to determine the alcohol content, which was then recorded as the alkoxy group content (m) (ppm). A flame ionization detector (FID) was used for the gas chromatograph. The gas chromatographic analysis was performed in accordance with JIS K0114.

[0123] <m / n 3 Value (ppm / nm 3 ) and m / n value (ppm / nm) m / n of abrasive grain 3 The m / n value and m / n value were calculated using the alkoxy group content m (ppm) and the average primary particle diameter n (nm) according to the following formulas. m / n 3 Value = (m [ppm]) / (n [nm]) 3 m / n value = (m [ppm]) / (n [nm])

[0124] 3.3. Preparation of Chemical Mechanical Polishing Composition The components were mixed to obtain the composition shown in Table 2 or Table 3 below, and then potassium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Ltd., product name "48% Potassium Hydroxide Aqueous Solution") or hydrochloric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Hydrochloric Acid") was added as needed to adjust the pH to the value shown in Table 2 or Table 3 below, and pure water was added so that the total amount of all components was 100 mass% to prepare chemical mechanical polishing compositions for each example and comparative example.

[0125] 3.4. Method for evaluating chemical mechanical polishing compositions 3.4.1. Evaluation of polishing speed Using the chemical mechanical polishing composition prepared above, a chemical mechanical polishing test was performed for 60 seconds under the following polishing conditions on a 12-inch diameter wafer with a 300 nm p-TEOS film (silicon oxide film) as the polishing target.

[0126] <Polishing conditions> Polishing equipment: Applied Materials, 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 Polishing rate (Å / min) = (film thickness before polishing - film thickness after polishing) / polishing time The thickness of the p-TEOS film was evaluated using an optical interference film thickness meter "NanoSpec 6100" (Nanometrics Japan).

[0127] The evaluation criteria for the polishing rate are as follows. The results of the polishing rate evaluation are also shown. (Evaluation criteria for p-TEOS film removal rate results) "A": When the polishing rate for the p-TEOS film is 500 Å / min or more, it is judged to be extremely good because it allows for extremely efficient processing of semiconductors in actual semiconductor polishing. "B": If the polishing rate of the p-TEOS film is 300 Å / min or more and less than 500 Å / min, it is judged to be very good because it is possible to process semiconductors efficiently in actual semiconductor polishing. "C": If the polishing rate of the p-TEOS film is 100 Å / min or more and less than 300 Å / min, it is judged to be good because it is possible to process semiconductors within the acceptable range of time in actual semiconductor polishing. "D": When the polishing rate of the p-TEOS film is less than 100 Å / min, it is judged to be defective because it will hinder the semiconductor throughput in actual semiconductor polishing.

[0128] 3.4.2. Defect Assessment Using the chemical mechanical polishing composition prepared 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 300 nm p-TEOS film as the polishing target.

[0129] <Polishing conditions> Polishing equipment: Applied Materials, 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

[0130] The p-TEOS film 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 shown in Table 2 or Table 3 below. (Defect count 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 cause problems.

[0131] 3.4.3. Foaming evaluation A foaming evaluation was performed using the chemical mechanical polishing composition prepared above. A plastic measuring cylinder with a height of 50 cm and an inner diameter of 6.2 cm was placed on a horizontal surface, and 100 g of the chemical mechanical polishing composition was poured into the measuring cylinder while avoiding foaming. A plastic burette was placed 70 cm vertically from the center of the bottom of the measuring cylinder, with its tip positioned at a position 70 cm vertically from the center of the bottom of the measuring cylinder. Next, 100 g of the chemical mechanical polishing composition was poured into the burette while avoiding foaming. The cock of the burette was then opened, and the chemical mechanical polishing composition was dripped onto the center of the liquid surface of the measuring cylinder at a constant rate over 10 seconds. After the dripping was completed, the system waited 5 minutes and then read the scale at the top of the bubbles. The amount of foaming was determined by subtracting 200 mL from the read scale (unit: mL).

[0132] The evaluation criteria for foaming evaluation are as follows. The results are shown in Table 2 or Table 3 below. . (Evaluation criteria) "A": When the amount of foaming is less than 10 mL, the waiting time until foaming subsides during production of the chemical mechanical polishing composition can be significantly reduced, and therefore the result was judged to be extremely good. "B": When the amount of foaming is 10 mL or more but less than 20 mL, the waiting time until foaming subsides during production of the chemical mechanical polishing composition can be shortened, and therefore the result was judged to be very good. "C": When the amount of foaming is 20 mL or more but less than 40 mL, the waiting time until the foaming subsides during production of the chemical mechanical polishing composition is acceptable in a mass production process, and therefore the result was judged to be good. "D": If the amount of foaming was 40 mL or more, the waiting time until the foaming subsided during the production of the chemical mechanical polishing composition was unacceptable even in a mass production process, and the composition was therefore judged to be defective.

[0133] 3.5.Evaluation Results Tables 2 and 3 below show the compositions of the chemical mechanical polishing compositions of the examples and comparative examples, as well as the evaluation results.

[0134] [Table 2]

[0135] [Table 3]

[0136] In Tables 2 and 3 above, the numerical values ​​for each component represent mass %. In each example and comparative example, the total amount of each component is 100 mass %, with the remainder being ion-exchanged water. Here, we will provide additional explanations for each component in Tables 2 and 3 above.

[0137] The following products or reagents were used for each component in Tables 2 and 3. For components with listed component concentrations, the components were added to and mixed with the chemical mechanical polishing composition so that the component concentrations were as shown in Tables 2 and 3. For components without listed component concentrations, the components were treated as if they were 100% in the product or reagent. <(B) component> Malonic acid: Kanto Chemical Co., Ltd., product name "malonic acid" Acetic acid: Kanto Chemical Co., Ltd., product name "Acetic acid" Maleic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Maleic acid" Tartaric acid: Fujifilm Wako Pure Chemical Industries, Ltd., trade name "L(+)-tartaric acid" Dipotassium hexadecenyl succinate: Kao Corporation, product name "Latemul ASK", ingredient concentration 28% Adipic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "adipic acid" Nitric acid: Kanto Chemical Co., Ltd., product name "Nitric acid 1.38", concentration 60% Phosphoric acid: Rasa Industries, product name "85% Phosphoric Acid", concentration 85% Para-toluenesulfonic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "p-toluenesulfonic acid monohydrate" Citric acid: Fuso Chemical Co., Ltd., product name "Purified Citric Acid (Crystal) L" Sulfuric acid: Kanto Chemical Co., Ltd., product name "High-purity sulfuric acid (96%)", component concentration 96% Pyromellitic acid: 1,2,4,5-benzenetetracarboxylic dianhydride, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Glycine: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Glycine" Dodecyliminodipropionic acid monosodium salt: Takemoto Oil & Fat Co., Ltd., product name "Takesurf C-158D," ingredient concentration 31% Lysine: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "L(+)-lysine" Polystyrene sulfonic acid: Shima Trading Co., Ltd., product name "VERSA-TL502" Polyacrylic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Polyacrylic acid 5,000" Ethylenediaminetetraacetic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Ethylenediaminetetraacetic Acid" <Other ingredients> Hydrogen peroxide: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Hydrogen Peroxide," concentration 30% Methylisothiazoline: Sigma-Aldrich, trade name "2-methyl-4-isothiazolin-3-one" Chloromethylisothiazoline: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "5-chloro-2-methyl-3-isothiazolone" Ammonia: Fujifilm Wako Pure Chemical Industries, Ltd., product name "ammonia water", concentration 29% Monoethanolamine: Hayashi Pure Chemical Industries, Ltd., trade name "Ethanolamine" Tetraethylammonium Hydroxide: Manufactured by Tokyo Chemical Industry Co., Ltd., product name "Tetraethylammonium Hydroxide", concentration 35% Iron(III) chloride: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Iron(III) chloride hexahydrate" Orthoperiodic acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Orthoperiodic acid" Boric acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "boric acid" Hypochlorous acid: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "Sodium hypochlorite", concentration 8%

[0138] According to the evaluation results in Tables 2 and 3 above, when the chemical mechanical polishing compositions of Examples 1 to 15 were used, the polishing rate evaluation, defect evaluation, and foaming evaluation all showed good results.

[0139] The chemical mechanical polishing compositions of Comparative Examples 1 and 3 were m / n 3 This is an example in which a chemical mechanical polishing composition containing abrasive grains F having a value of less than 0.1 was used. In this case, the polishing rate was within the acceptable range. On the other hand, m / n 3 The low value resulted in a poor defect rating.

[0140] The chemical mechanical polishing compositions of Comparative Examples 2 and 4 were examples in which a chemical mechanical polishing composition containing abrasive grains G in which the proportion of particles having a bent and / or branched structure was less than 15% was used. In these cases, the removal rate evaluation was poor due to the small proportion of particles having a bent and / or branched structure.

[0141] The chemical mechanical polishing compositions of Comparative Examples 5 to 7 were examples in which a chemical mechanical polishing composition not containing component (B) was used. In these cases, the polishing rate evaluation and defect evaluation were good, but foaming was poor due to the absence of component (B).

[0142] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations with the same 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]

[0143] 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) silica particles; (B) at least one selected from the group consisting of organic acids, nitric acid, sulfuric acid, and phosphoric acid; (C) a liquid medium; A chemical mechanical polishing composition comprising: When the alkoxy group content of the (A) silica particles is m (ppm) and the average primary particle diameter is n (nm), m / n ３ The value is 0.1 or more, A chemical mechanical polishing composition in which the (A) silica particles contain 15% or more silica particles having a bent structure and / or branched structure, based on the number of particles in an arbitrary field of view at 200,000 magnifications observed with a scanning electron microscope.

2. The chemical mechanical polishing composition according to claim 1 , wherein the component (A) contains 2000 ppm by mass or more of alkoxy groups per 1 g of silica particles.

3. The true specific gravity of the component (A) is 1.95 g / cm ３ The chemical mechanical polishing composition according to claim 1 or 2, wherein the composition is as described above.

4. 3. The chemical mechanical polishing composition according to claim 1, wherein the component (A) contains at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines in an amount of 5 μmol or more per gram of silica particles.

5. A chemical mechanical polishing composition according to claim 1 or claim 2, wherein when the content of the (A) component is MA [mass %] and the content of the (B) component is MB [mass %], MA / MB = 0.1 to 600.

6. 3. The chemical mechanical polishing composition according to claim 1, wherein the component (B) is a carboxylic acid or a salt of a carboxylic acid.

7. The chemical mechanical polishing composition of claim 1 or 2, which has a pH of 1 or more and 7 or less.

8. 3. The chemical mechanical polishing composition according to claim 1, wherein the component (A) has at least one functional group selected from the functional groups represented by the following general formulas (1) to (4): -SO ３ － M ＋ ・・・・・(1) -COO － M ＋ ・・・・・(2) (In the above formulas (1) and (2), M ＋ represents a monovalent cation.) -NR １ R ２ ・・・・・・(3) -N ＋ R １ R ２ R ３ M － ・・・・・(4) (In the above formulas (3) and (4), R １ , R ２ and R ３ Each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group. － represents an anion.)

9. The chemical mechanical polishing composition according to claim 8, wherein the component (A) is a silica particle having at least one functional group selected from the functional groups represented by the general formulas (1) to (4) fixed to its surface via a covalent bond.

10. 3 . The chemical mechanical polishing composition according to claim 1 , wherein the content of the component (A) is 0.1% by mass or more and 20% by mass or less, based on 100% by mass of the chemical mechanical polishing composition.

11. A polishing method comprising the step of polishing a semiconductor substrate with the chemical mechanical polishing composition of claim 1 or 2.

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