Polishing composition and polishing method

Abstract

According to this disclosure, when the pH of the polishing composition is less than 7, a means is provided that can achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having silicon-silicon bonds to the polishing rate of materials having oxygen-silicon bonds. [Solution] This disclosure relates to an abrasive composition comprising the following component (A) and component (B), having a pH of less than 7; (A) Component: Surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles; (B) Ingredient: Water.

Description

Technical Field

[0001] The present invention relates to a polishing composition and a polishing method.

Background Art

[0002] In recent years, with the multilayer wiring of the semiconductor substrate surface, when manufacturing a device, a so-called Chemical Mechanical Polishing (CMP) technique of physically polishing and planarizing the semiconductor substrate is used. CMP is, for example, a method of planarizing the surface of an object to be polished such as a semiconductor substrate using a polishing composition (slurry) containing abrasive grains (for example, silica and / or ceria, etc.) and additives (for example, corrosion inhibitors and / or surfactants, etc.). CMP is specifically used in processes such as shallow trench isolation (STI), planarization of an interlayer insulating film (ILD film), tungsten plug formation, and / or formation of a multilayer wiring composed of copper and a low dielectric constant film.

[0003] Patent Document 1 discloses colloidal silica surface-modified with polyethylene oxide having a molecular weight of 15,000 or less and a polishing composition for CMP containing the same.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the pH of the polishing composition is less than 7, there is a need for a means to improve the polishing speed of materials containing silicon-silicon bonds. However, the technology described in Patent Document 1 is mainly intended for use in polishing wiring layers made of copper-based wiring materials, barrier metal layers made of tantalum-based materials, and / or insulating layers made of silica (silicon oxide)-based materials. Furthermore, in the technology of Patent Document 1, the pH of the polishing composition for CMP is assumed to be between 8 and 6. Patent Document 1 also discloses that, regarding the pH of the polishing composition for CMP, a sufficient polishing speed may not be obtained if the pH of the polishing composition is between 6 and 8, and that polishing of the barrier layer occurs if the pH of the polishing composition is less than 6. However, Patent Document 1 does not disclose any specific effects on polishing materials containing silicon-silicon bonds. Furthermore, the technology of Patent Document 1 has the problem that when the pH of the polishing composition is less than 7, the polishing speed of materials containing silicon-silicon bonds may not be sufficient.

[0006] Therefore, the present invention provides a means to achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having silicon-silicon bonds to the polishing rate of materials having oxygen-silicon bonds, when the pH of the polishing composition is less than 7. [Means for solving the problem]

[0007] To solve the above problems, the inventors diligently conducted research. As a result, they discovered that the above problems could be solved by incorporating specific surface-modified silica particles into an abrasive composition with a pH of less than 7, thus completing the present invention.

[0008] One aspect of the present invention, for solving at least one of the above problems, relates to an abrasive composition comprising the following component (A) and component (B), and having a pH of less than 7; (A) Component: Surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles; (B) Ingredient: Water. [Effects of the Invention]

[0009] According to the present invention, when the pH of the polishing composition is less than 7, a means is provided that can achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having silicon-silicon bonds to the polishing rate of materials having oxygen-silicon bonds. [Modes for carrying out the invention]

[0010] <Polishing composition> One aspect of the present invention relates to an abrasive composition comprising the following component (A) and component (B), and having a pH of less than 7.

[0011] (A) Component: Surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles; (B) Ingredient: Water.

[0012] According to an abrasive composition of one embodiment of the present invention, when the pH of the abrasive composition is less than 7, it is possible to achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having silicon-silicon bonds to the polishing rate of materials having oxygen-silicon bonds.

[0013] The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described below. The embodiments described herein can be combined in any way to form other embodiments.

[0014] In this specification, "X~Y" indicating a numerical range means that the numbers (X and Y) before and after it are included as the lower and upper limits, respectively, and means "X or greater and Y or less." In this specification, "A and / or B" means that A, B, and any combination thereof are included. In this specification, unless otherwise specified, operations and measurements of physical properties, etc., are performed under conditions of room temperature (20°C to 25°C) and relative humidity of 40%RH to 50%RH.

[0015] [(A) component] (A) Component is a surface-modified silica particle comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles.

[0016] In one embodiment, component (A) is suitably used as abrasive grains. The polishing composition according to one embodiment contains abrasive grains, and it is preferable that the abrasive grains contain component (A). The polishing composition according to one embodiment contains abrasive grains, and it is more preferable that the abrasive grains consist only of component (A).

[0017] In this specification, surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles, are also referred to as "(A) component surface-modified silica particles".

[0018] (Silica particles) (A) The silica particles contained in the surface-modified silica particles of component (A) (hereinafter also simply referred to as "silica particles") are not particularly limited, but include fumed silica and colloidal silica. The silica particles are preferably colloidal silica. Examples of methods for producing colloidal silica include the sodium silicate method and the sol-gel method. However, colloidal silica produced by any of these methods can be suitably used. Among these, colloidal silica produced by the sol-gel method is preferred from the viewpoint of reducing metal impurities. Colloidal silica produced by the sol-gel method tends to have a low content of diffusible corrosive ions in the semiconductor (e.g., metal impurities and / or chloride ions). Colloidal silica can be produced by the sol-gel method using conventionally known methods. Specifically, colloidal silica can be obtained by using a hydrolyzable silicon compound (e.g., alkoxysilane or its derivatives) as a raw material and carrying out a hydrolysis-condensation reaction.

[0019] The lower limit of the average primary particle diameter of silica particles is not particularly limited, but is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 7 nm or more. As the average primary particle diameter of the abrasive grains increases, the polishing speed of the object to be polished by the polishing composition improves. The upper limit of the average primary particle diameter of silica particles is not particularly limited, but is preferably 100 nm or less, more preferably 75 nm or less, and even more preferably 50 nm or less. The average primary particle diameter of silica particles is calculated, for example, based on the specific surface area of ​​the silica particles measured by the BET method.

[0020] The lower limit of the average secondary particle diameter of silica particles is not particularly limited, but is preferably 2 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and particularly preferably 25 nm or more. Within these ranges, the resistance during polishing is reduced, and stable polishing becomes possible. The upper limit of the average secondary particle diameter of silica particles is not particularly limited, but is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 120 nm or less, and particularly preferably 90 nm or less. Within these ranges, the surface area per unit mass of abrasive grains is increased, the frequency of contact with the workpiece is improved, and the polishing speed is further improved. Examples of the average secondary particle diameter range of silica particles include 2 nm to 200 nm, 10 nm to 150 nm, 15 nm to 120 nm, and 25 nm to 90 nm. The average secondary particle diameter of silica particles can be measured, for example, by dynamic light scattering methods such as laser diffraction scattering.

[0021] The average degree of association of silica particles is not particularly limited, but is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. The average degree of association of silica particles is not particularly limited, but is preferably 1.0 or more, more preferably 1.2 or more, and even more preferably 1.5 or more. The average degree of association of silica particles is obtained by dividing the value of the average secondary particle diameter of the silica particles by the value of the average primary particle diameter of the silica particles.

[0022] The shape of silica particles is not particularly limited and may be spherical or non-spherical. Various non-spherical shapes can be cited. Examples of non-spherical shapes are not particularly limited but include polygonal prisms, cylinders, cylindrical shapes where the center of the cylinder is wider than the ends, donut shapes where the center of the disk is penetrated, plate shapes, so-called cocoon shapes with a constriction in the center, so-called aggregate spherical shapes where multiple particles are integrated, so-called konpeito shapes with multiple protrusions on the surface, and rugby ball shapes. Examples of polygonal shapes are not particularly limited but include triangular prisms and square prisms.

[0023] (Surface modification group) The surface-modified silica particles of component (A) contain surface-modifying groups that include polyoxyalkylene chains. The surface-modifying groups contained in the surface-modified silica particles of component (A) contain polyoxyalkylene chains having a weight-average molecular weight of 80 to 7,000. In this specification, the polyoxyalkylene chains contained in the surface-modifying groups are also referred to as "polyoxyalkylene chains in the surface-modifying groups".

[0024] The polyoxyalkylene chain in the surface modification group may consist of only one type of oxyalkylene, or it may consist of two or more types of oxyalkylene. Examples of polyoxyalkylene chains in the surface modification group are not particularly limited, but include polyoxyethylene chains, polyoxypropylene chains, polyoxytrimethylene chains, polyoxytetramethylene chains, polyoxyisobutylene chains, polyoxyethylene-polyoxypropylene chains, polyoxyethylene-polyoxytetramethylene chains, and polyoxyethylene-polyoxypropylene-polyoxyethylene chains. When the polyoxyalkylene chain in the surface modification group consists of two or more types of oxyalkylene, the bonding configuration of the two or more oxyalkylenes may be random, alternating, blocked, periodic, or a combination thereof. It is preferable that the polyoxyalkylene chain in the surface modification group includes at least one type of polyoxyalkylene chain selected from the group consisting of the polyoxyalkylene chains exemplified above. The polyoxyalkylene chain in the surface modification group is preferably at least one selected from the group consisting of polyoxyethylene chains, polyoxypropylene chains, polyoxyethylene-polyoxypropylene chains, and polyoxyethylene-polyoxypropylene-polyoxyethylene chains, and more preferably a polyoxyethylene chain.

[0025] The polyoxyalkylene chain in the surface modification group may have a structure in which the ends of the polyoxyalkylene chain are sealed. For example, the polyoxyalkylene chain in the surface modification group may have a structure in which the ends of the polyoxyalkylene chain are sealed with an aliphatic hydrocarbon group. The hydrogen atom of the hydroxyl group at one end of the polyoxyalkylene chain in the surface modification group may be substituted with an aliphatic hydrocarbon group. Examples of aliphatic hydrocarbon groups that seal the ends of the polyoxyalkylene chain in the surface modification group are not particularly limited, but include aliphatic hydrocarbon groups having 1 to 10 carbon atoms. Examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are not particularly limited, but include linear or branched alkyl groups, linear or branched alkenyl groups, and alkynyl groups. Examples of linear or branched alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, and decyl groups. Examples of linear or branched alkenyl groups include, but are not limited to, vinyl and allyl groups. Examples of alkynyl groups include, but are not limited to, ethynyl and propynyl groups.

[0026] The weight-average molecular weight (Mw) of the polyoxyalkylene chains contained in the surface modification group is between 80 and 7,000. That is, the weight-average molecular weight (Mw) of the polyoxyalkylene chains in the surface modification group is the weight-average molecular weight (Mw) of the compound containing the polyoxyalkylene chains, and is between 80 and 7,000. For example, the weight-average molecular weight (Mw) of the polyoxyalkylene chains in the surface modification group is the weight-average molecular weight (Mw) of the compound containing the polyoxyalkylene chains, which are the raw materials for constituting the polyoxyalkylene chains in the surface modification group, and is between 80 and 7,000. If the weight-average molecular weight of the polyoxyalkylene chains in the surface modification group is less than 80, the ratio of the polishing rate of materials with silicon-silicon bonds to the polishing rate of materials with oxygen-silicon bonds becomes large. If the weight-average molecular weight of the polyoxyalkylene chains in the surface modification group is greater than 7,000, aggregation of surface-modified silica particles may occur in polishing compositions with a pH of less than 7.

[0027] The lower limit of the weight-average molecular weight of the polyoxyalkylene chain in the surface modification group is not particularly limited as long as it is 80 or higher, but it is preferably 100 or higher, more preferably 140 or higher, even more preferably 200 or higher, and particularly preferably 300 or higher. The upper limit of the weight-average molecular weight of the polyoxyalkylene chain in the surface modification group is not particularly limited as long as it is 7,000 or lower, but it is preferably 5,000 or lower, more preferably 2,000 or lower, even more preferably 600 or lower, and particularly preferably 500 or lower. In one embodiment, examples of weight-average molecular weight of the polyoxyalkylene chain in the surface modification group are not particularly limited, but include 80 to 5,000, 80 to 2,000, 80 to 600, 80 to 500, 100 to 5,000, 140 to 2,000, 200 to 600, 300 to 500, and so on. Within these ranges, when the pH of the polishing composition is less than 7, the polishing rate of materials containing silicon-silicon bonds is improved, and the ratio of the polishing rate of materials containing silicon-silicon bonds to the polishing rate of materials containing oxygen-silicon bonds is within a better range. The weight-average molecular weight of compounds containing polyoxyalkylene chains can be measured by gel permeation chromatography (GPC) using polyethylene glycol as the standard substance.

[0028] The surface-modifying groups contained in the surface-modified silica particles of component (A) preferably include silicon atoms and linking groups, and more preferably at least one group selected from the group consisting of the group represented by formula (1), the group represented by formula (2), and the group represented by formula (3). The bonds indicated by the wavy lines in formulas (1) to (3) below are bonded to the surface of the silica particles.

[0029] [ka]

[0030] In the above equations (1) to (3), R 1Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, R 2 Each independently represents an alkylene group, n is each independently the average degree of polymerization (number average degree of polymerization) of the oxyalkylene chain [-(O-R 2 )-], and is a number of 2 or more and 200 or less, X each independently represents a single bond or a linking group (a divalent group having 1 or more atoms), R 3 and R 4 each independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, or a group represented by the following formula (a),

[0031]

Chemical formula

[0032] In the above formula (a), R A each independently represents [-X-(O-R 2 ) n -OR 1 )], and at this time, X, R A in R 1 , R 2 , and n are each the X, R 1 , R 2 , and n defined by the above formulas (1) to (3), respectively, and R 5 and R 6 each independently represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and l and m each independently represent a number of 0 or more. In the formula (a), the bond extending from the silicon atom to the left is bonded to an oxygen atom. The wavy bond in the formula (a) is bonded to the surface of the silica particle.

[0033] In the above formulas (1) to (3), R 1Examples of hydrocarbon groups with 1 to 30 carbon atoms used in this context are not limited to alkyl groups, alkenyl groups, phenyl groups, naphthyl groups, alkylaryl groups, arylalkyl groups, and arylalkenyl groups. Examples of the alkyl groups mentioned above are not limited to methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, isobutyl group, amyl group, isoamyl group, tert-amyl group, n-hexyl group, cyclohexyl group, cyclohexylmethyl group, 2-cyclohexylethyl group, n-heptyl group, isoheptyl group, tert-heptyl group, n-octyl group, isooctyl group, tert-octyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, and the like. Examples of the above alkenyl groups are not limited to vinyl group, but include vinyl group, 1-methylethenyl group, 2-methylethenyl group, propenyl group, butenyl group, isobutenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, decenyl group, pentadecenyl group, and 1-phenylpropen-3-yl. Examples of the alkylaryl groups mentioned above are not particularly limited, but include, for example, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-vinylphenyl group, 3-isopropylphenyl group, 4-isopropylphenyl group, 4-butylphenyl group, 4-isobutylphenyl group, 4-tert-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, 4-octylphenyl group, 4-(2-ethylhexyl)phenyl group, 4-stearylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, and 2,4-di-tert-butylphenyl group. Examples of the arylalkyl groups mentioned above are not particularly limited, but include benzyl group, phenethyl group, 2-phenylpropan-2-yl group, diphenylmethyl group, and triphenylmethyl group.Examples of the aryl alkenyl groups mentioned above are not limited to those mentioned above, but include, for example, a styryl group and a cinnamyl group.

[0034] In the above equations (1) to (3), R 2 R represents an alkylene group, preferably an alkylene group having 1 to 4 carbon atoms. Examples of alkylene groups having 1 to 4 carbon atoms are not particularly limited, but include methylene group, ethylene group, propylene group (methylethylene group), trimethylene group, butylene group (tetramethylene group), isobutylene group, etc. Among these, R 2 It is preferable that it is an ethylene group or a propylene group. Multiple R 2 These may be the same or different. Multiple R 2 If different, the above oxyalkylene chain [-(OR 2 The combination of )-] may be random, alternating, block, periodic, or a combination thereof.

[0035] In the above formulas (1) to (3), n is the oxyalkylene chain [-(OR 2 This represents the average degree of polymerization (number-average degree of polymerization) of )-], and is a number between 2 and 200. n is preferably a number between 3 and 150, more preferably a number between 4 and 100, even more preferably a number between 5 and 50, and particularly preferably a number between 6 and 10. Within these ranges, when the pH of the polishing composition is less than 7, the polishing speed of the silicon-silicon bond material is further improved, and the ratio of the polishing speed of the silicon-silicon bond material to the polishing speed of the oxygen-silicon bond material is within a better range.

[0036] In formulas (1) to (3) above, X represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the above linking groups are not limited to, but include divalent hydrocarbon groups, urethane bonds, carbonyl groups, ether bonds, ester bonds, carbonate groups, amide groups, and groups formed by linking one or more of these groups.

[0037] Examples of the divalent hydrocarbon groups mentioned above include linear alkylene groups having 1 to 18 carbon atoms, branched alkylene groups having 1 to 18 carbon atoms, or cyclic alkylene groups having 1 to 18 carbon atoms. Examples of linear alkylene groups having 1 to 18 carbon atoms, branched alkylene groups having 1 to 18 carbon atoms, or cyclic alkylene groups having 1 to 18 carbon atoms are not particularly limited, but include methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group (methylethylene group), trimethylene group, butylene group (tetramethylene group), 1-methylpropylene group, 2-methylpropylene group, 1,2-dimethylpropylene group, 1,3-dimethylpropylene group, 1-methylbutylene group, 2-methylbutylene group, 3-methylbutylene group, 2,4-dimethylbutylene group, 1,3-dimethylbutylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, ethane-1 Examples include 1-diyl group, propane-2,2-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, cyclopentane-1,2-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,1-diyl group, cyclohexane-1,2-diyl group, cyclohexane-1,3-diyl group, cyclohexane-1,4-diyl group, methylcyclohexane-1,4-diyl group, and cyclohexane-1,4-dimethylene group.

[0038] The linking group in X above preferably contains a urethane bond for ease of synthesis, and more preferably contains a divalent hydrocarbon group (particularly a linear or branched alkylene group) and a urethane bond. Furthermore, it is preferable that the silicon atom in formulas (1) to (3) above is directly bonded to the divalent hydrocarbon group (particularly a linear or branched alkylene group) in X. Specifically, X is -(CH2) kIt is more preferable that the compound is -NH-C(=O)- (where the leftmost C is bonded to a silicon atom and the rightmost C is bonded to an O in the polyoxyalkylene chain). In the above formula, k represents a number between 1 and 18, preferably between 1 and 6, and more preferably between 1 and 3.

[0039] In the above equation (1), R 3 and R 4 Each of these independently represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms. Examples of aliphatic hydrocarbon groups having 1 to 3 carbon atoms are, but are not limited to, alkyl groups, alkenyl groups, and alkynyl groups. Examples of alkyl groups are, but are not limited to, methyl groups, ethyl groups, propyl groups, and isopropyl groups. Examples of alkenyl groups are, but are not limited to, vinyl groups and allyl groups. Examples of alkynyl groups are, but are not limited to, ethynyl groups and propynyl groups. Among these, R 3 and R 4 Each of them is preferably an alkyl group, R 3 and R 4 It is more preferable that both are alkyl groups. Note that R in formula (2) 3 R in equation (1) 3 It is similar to that.

[0040] In the above formula (a), R A is [-X-(OR 2 )n-OR 1 ] represents R A X, R 1 , R 2 , and n are the same as those exemplified and described for formulas (1) to (3) above, and the same applies to preferred embodiments. Also, oxyalkylene chain [-(OR 2 The bonding configuration when there are two or more types of )-] is as described above. Note that the bonds extending to the left from the silicon atom bond to the oxygen atom. The bonds indicated by the wavy lines in the formula bond to the surface of the silica particle.

[0041] In the above formula (a), R 5 and R 6 Each of these independently represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms. Examples of the above aliphatic hydrocarbon groups having 1 to 3 carbon atoms include linear or branched alkyl groups, linear or branched alkenyl groups, and alkynyl groups. Examples of the above linear or branched alkyl groups are not particularly limited, but include methyl groups, ethyl groups, n-propyl groups, and isopropyl groups. Examples of the above linear or branched alkenyl groups are not particularly limited, but include vinyl groups, allyl groups, and propenyl groups. Examples of the above alkynyl groups are not particularly limited, but include ethynyl groups and propynyl groups. Among these, R 5 and R 6 Each of these is preferably a linear or branched alkyl group, R 5 and R 6 It is more preferable that both are linear or branched alkyl groups.

[0042] In formula (a) above, l and m each independently represent a number greater than or equal to 0. The bonding order between the constituent unit with l and the constituent unit with m is not particularly limited. That is, the silicon atom in formula (a) that bonds with the oxygen atom in formula (1) or (2) may be a silicon atom in the constituent unit with l, or a silicon atom in the constituent unit with m. Similarly, in formula (a) R 6 The oxygen atom in formula (a) that is bonded with may be an oxygen atom in the constituent unit labeled l, or an oxygen atom in the constituent unit labeled m. Furthermore, if one of l and m is a number of 1 or more and the other is a number of 2 or more, the bonding pattern between the constituent unit labeled l and the constituent unit labeled m may be random, alternating, block, periodic, or a combination thereof.

[0043] (A) Surface-modified silica particles of component A, 1 , multiple R 2 , multiple R 3 , multiple R4 , multiple R 5 , multiple R 6 If there are multiple X, multiple l, multiple m and / or multiple n, then multiple R 1 , multiple R 2 , multiple R 3 , multiple R 4 , multiple R 5 , multiple R 6 Multiple X, multiple l, multiple m, and multiple n may be independent of each other, and may be the same or different.

[0044] In the above equations (1) and (2), R 3 and / or R 4 Structures in which R is a hydrogen atom represent, for example, structures resulting from the hydrolysis of unreacted alkoxysilyl groups in surface modification groups bonded to silica particles. In formulas (1) and (2) above, R 3 and / or R 4 Structures in which R is an aliphatic hydrocarbon group having 1 to 3 carbon atoms represent, for example, structures in which unreacted alkoxysilyl groups remain in surface modification groups bonded to silica particles. In formulas (1) and (2) above, R 3 and / or R 4 Structures in which the group is represented by formula (a) above include, for example, a structure in which an unreacted alkoxysilyl group in a surface modifying group bonded to silica particles reacts with an unreacted polyoxyalkylene chain-containing silane coupling agent described later, a structure in which an unreacted alkoxysilyl group in a surface modifying group bonded to silica particles reacts with an alkoxysilyl group in another surface modifying group bonded to silica particles by dehydration condensation, or a structure in which an unreacted alkoxysilyl group in a surface modifying group bonded to silica particles reacts with an unreacted polyoxyalkylene chain-containing silane coupling agent described later, and an alkoxysilyl group in another surface modifying group bonded to silica particles by dehydration condensation.

[0045] Component (A) preferably contains silica particles on which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent.

[0046] In silica particles in which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent, the silane coupling agent is not particularly limited. Preferred examples of silane coupling agents include isocyanate group-containing silane coupling agents. In silica particles in which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent, the silane coupling agent is not particularly limited, but it is preferable to include an isocyanate group-containing silane coupling agent, and more preferably to consist solely of an isocyanate group-containing silane coupling agent. Examples of isocyanate group-containing silane coupling agents are not particularly limited, but include 3-isocyanate-propyltrimethoxysilane, 3-isocyanate-propyldimethoxymethylsilane, 3-isocyanate-propyltriethoxysilane, isocyanate-methyltrimethoxysilane, isocyanate-methyltriethoxysilane, and isocyanate-methyldimethoxymethylsilane. These silane coupling agents can be used individually or in combination of two or more. The silane coupling agent preferably includes at least one silane coupling agent selected from the group consisting of the silane coupling agents exemplified above. The silane coupling agent is preferably an isocyanate group-containing silane coupling agent, and more preferably 3-isocyanatetopropyltrimethoxysilane. The silane coupling agent may be a commercially available product or a synthetic product.

[0047] In one embodiment, in silica particles in which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent, the compound containing the polyoxyalkylene chain is preferably a compound consisting only of polyalkylene glycol chains. The ends of the compound consisting only of polyalkylene glycol chains are unsealed. For example, the compound consisting only of polyalkylene glycol chains may be the same as the compound consisting only of polyalkylene glycol chains exemplified in the description of the compound containing a polyoxyalkylene chain having a weight-average molecular weight of 80 or more and 7,000 or less, which will be described later. The compound consisting only of polyalkylene glycol chains is more preferably at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer, and even more preferably polyethylene glycol. The compound containing the polyoxyalkylene chain is preferably polyalkylene glycol.

[0048] The lower limit of the average secondary particle diameter of the surface-modified silica particles in the polishing composition according to one embodiment is not particularly limited, but is preferably 2 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and particularly preferably 25 nm or more. Within these ranges, the resistance during polishing is reduced, and stable polishing becomes possible. The upper limit of the average secondary particle diameter of the surface-modified silica particles in the polishing composition according to one embodiment is not particularly limited, but is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 120 nm or less, and particularly preferably 90 nm or less. Within these ranges, the surface area per unit mass of abrasive grains is increased, the frequency of contact with the object to be polished is improved, and the polishing speed is further improved. Examples of the range of average secondary particle diameter of the surface-modified silica particles in the polishing composition according to one embodiment include 2 nm to 200 nm, 10 nm to 150 nm, 15 nm to 120 nm, and 25 nm to 90 nm. The average secondary particle diameter of the surface-modified silica particles in the polishing composition according to one embodiment can be measured, for example, by dynamic light scattering methods such as laser diffraction scattering.

[0049] The content of component (A) in the polishing composition according to one embodiment is not particularly limited. The lower limit of the content of component (A) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and particularly preferably 1.5% by mass or more, relative to the total mass of the polishing composition. For example, it may be 2% by mass or more relative to the total mass of the polishing composition. The upper limit of the content of surface-modifying silica particles of component (A) is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 8% by mass or less, even more preferably 6% by mass or less, and particularly preferably 5% by mass or less, relative to the total mass of the polishing composition (lower limit greater than 0% by mass). Within these ranges, the polishing speed can be improved while keeping costs down. Examples of the range of content of component (A) are not particularly limited, but include 0.1% to 20% by mass, 0.2% to 15% by mass, 0.5% to 10% by mass, 1% to 8% by mass, 1.5% to 6% by mass, and 2% to 5% by mass, relative to the total mass of the polishing composition. When the polishing composition according to one embodiment contains two or more surface-modified silica particles as component (A), the content of component (A) represents the total content of these particles.

[0050] (Method for producing surface-modified silica particles) The method for producing surface-modified silica particles of component (A) is not particularly limited, and known methods may be used as appropriate. Examples of methods for producing surface-modified silica particles of component (A) include the methods described in (a1) and (b1) below; (a1) Pre-synthesize a polyoxyalkylene chain-containing silane coupling agent (also referred to herein as a "surface modifier") using a silane coupling agent having a group that can react with the terminal hydroxyl group of a compound containing a polyoxyalkylene chain having a weight-average molecular weight of 80 or more and 7,000 or less, and a compound containing a polyoxyalkylene chain, and A silane coupling agent containing a polyoxyalkylene chain is reacted with silica particles (preferably colloidal silica). A method that includes; (b1) A silane coupling agent having a group that can react with the terminal hydroxyl group of a compound containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000 is reacted with silica particles (preferably colloidal silica), and then the compound containing the polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000 is further reacted. A method that includes this.

[0051] Among these methods, method (a1) is preferred because it allows for easier control of the reaction and further reduces manufacturing costs. Method (a1) will be described below.

[0052] <<Process for synthesizing polyoxyalkylene chain-containing silane coupling agents>> In this process, a silane coupling agent having a group that can react with the terminal hydroxyl group of a compound containing a polyoxyalkylene chain is reacted with a compound containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000 to synthesize a polyoxyalkylene chain-containing silane coupling agent (surface modifier).

[0053] The silane coupling agent having a group that can react with the terminal hydroxyl group of a compound containing a polyoxyalkylene chain is not particularly limited, but isocyanate group-containing silane coupling agents are preferred. Examples of isocyanate group-containing silane coupling agents are not particularly limited, but include 3-isocyanate-propyltrimethoxysilane, 3-isocyanate-propyldimethoxymethylsilane, 3-isocyanate-propyltriethoxysilane, isocyanate-methyltrimethoxysilane, isocyanate-methyltriethoxysilane, and isocyanate-methyldimethoxymethylsilane. These silane coupling agents can be used individually or in combination of two or more. The silane coupling agent preferably contains at least one silane coupling agent selected from the group consisting of the silane coupling agents exemplified above. The silane coupling agent is preferably an isocyanate group-containing silane coupling agent, and more preferably 3-isocyanate-propyltrimethoxysilane. The silane coupling agent may be a commercially available product or a synthetic product.

[0054] Examples of compounds containing polyoxyalkylene chains having a weight-average molecular weight of 80 to 7,000 include, but are not limited to, polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polyisobutylene glycol, ethylene glycol-propylene glycol copolymer, and ethylene glycol-tetramethylene glycol copolymer. The bonding configuration of the copolymer may be random, alternating, block, periodic, or a combination thereof. These compounds containing polyoxyalkylene chains can be used individually or in combination of two or more. Preferably, the compound containing polyoxyalkylene chains contains at least one compound selected from the group consisting of the polyoxyalkylene chain compounds exemplified above. Preferably, the compound containing polyoxyalkylene chains is polyalkylene glycol, more preferably at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer, and even more preferably polyethylene glycol. A preferred embodiment of the weight-average molecular weight of a compound containing a polyoxyalkylene chain is the same as the preferred embodiment of the weight-average molecular weight of the polyoxyalkylene chain described above.

[0055] For example, a compound containing a polyoxyalkylene chain with a weight-average molecular weight of 80 to 7,000 may have a structure in which one end of the polyoxyalkylene chain is sealed. For example, a compound containing a polyoxyalkylene chain with a weight-average molecular weight of 80 to 7,000 may have a structure in which one end of the polyoxyalkylene chain is sealed with an aliphatic hydrocarbon group. That is, the hydrogen atom in the hydroxyl group at one end of a compound containing a polyoxyalkylene chain with a weight-average molecular weight of 80 to 7,000 may be replaced with an aliphatic hydrocarbon group. Examples of aliphatic hydrocarbon groups that seal one end of a polyoxyalkylene with a weight-average molecular weight of 80 to 7,000 are not particularly limited, but include aliphatic hydrocarbon groups having 1 to 10 carbon atoms. Examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are not particularly limited, but include linear or branched alkyl groups, linear or branched alkenyl groups, alkynyl groups, etc. Examples of alkynyl groups are not limited to ethynyl groups and propynyl groups.

[0056] In one embodiment, the compound containing the polyoxyalkylene chain is preferably a polyalkylene glycol, a compound having a structure in which one end of the polyoxyalkylene chain is sealed, or a combination thereof.

[0057] Compounds containing polyoxyalkylene chains may be commercially available or synthetically synthesized.

[0058] The reaction between the above-mentioned silane coupling agent and the compound containing the polyoxyalkylene chain is not particularly limited and can be carried out, for example, without a solvent or in an organic solvent. Examples of organic solvents that can be used are not particularly limited, but include aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, aprotic polar solvents, halogenated hydrocarbons, linear or cyclic ethers, esters, linear ketones, and nitriles. Examples of aliphatic hydrocarbons are not particularly limited, but include hexane, heptane, and octane. Examples of aromatic hydrocarbons are not particularly limited, but include benzene, toluene, and xylene. Examples of alicyclic hydrocarbons are not particularly limited, but include cyclohexane and methylcyclohexane. Examples of aprotic polar solvents are not particularly limited, but include dimethylformamide (DMF), dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide. Examples of halogenated hydrocarbons are not particularly limited, but include chloroform, dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, and trifluoromethylbenzene. Examples of linear or cyclic ethers include, but are not limited to, diethyl ether, diisopropyl ether, dimethoxyethane, tetrahydrofuran (THF), and dioxane. Examples of esters include, but are not limited to, ethyl acetate and butyl acetate. Examples of linear ketones include, but are not limited to, methyl ethyl ketone (MEK) and methyl isobutyl ketone. Examples of nitriles include, but are not limited to, acetonitrile.

[0059] A surface modifier can be obtained by mixing a silane coupling agent with a compound containing polyoxyalkylene chains. A preferred mixing method is to add the silane coupling agent to the compound containing polyoxyalkylene chains and then mix. In this case, the silane coupling agent may be added all at once, in installments, or continuously. The addition rate in the case of continuous addition can be adjusted as appropriate. If the compound containing polyoxyalkylene chains is in solid form, it may be heated to a liquid state before mixing.

[0060] The stirring speed during mixing is not particularly limited and can be set as appropriate. The mixing time is preferably between 15 minutes and 2 hours.

[0061] The reaction temperature after mixing is preferably between 20°C and 200°C, and more preferably between 50°C and 150°C. The reaction time after mixing is 2,260 cm⁻¹ when the FT-IR spectrum of the surface modifier is measured. -1 It is preferable that the intensity of the peak of the isocyanate group derived from the nearby silane coupling agent is 10% or less compared to immediately after mixing, and more preferably that the peak disappears. The reaction atmosphere may be any of the following, for example, an air atmosphere, a nitrogen atmosphere, an argon atmosphere, or other inert gas atmosphere, and is not particularly limited. The pressure during the reaction may also be any of the following, for example, normal pressure (atmospheric pressure), pressurized pressure, or reduced pressure, and is not particularly limited. Since the reaction can proceed under normal pressure (atmospheric pressure), it is preferable to carry out the reaction under normal pressure (atmospheric pressure).

[0062] The molar ratio of the silane coupling agent to the compound containing the polyoxyalkylene chain (silane coupling agent / compound containing the polyoxyalkylene chain) is preferably 0.5 to 1.5.

[0063] In this way, a surface modifier can be obtained. The structure of the surface modifier can be confirmed, for example, by measuring the infrared absorption spectrum using the total internal reflection (ATR) method with a Fourier transform infrared spectrophotometer (FT-IR). Details of this method are described in the examples.

[0064] After this process, the surface modifier may be isolated and purified, or the next step (reacting silica particles with the surface modifier) ​​may be performed without isolation and purification.

[0065] <<Process of reacting silica particles with a surface modifier>> It is preferable to react the surface modifier obtained above with silica particles to obtain surface-modified silica particles of component (A). The silica particles have silanol groups on their surface, and these silanol groups act as reaction sites, forming siloxane bonds with the surface modifier.

[0066] The surface modifier (polyoxyalkylene chain-containing silane coupling agent) is preferably a compound represented by the following formula (1'). The surface modifier may be used alone or in combination of two or more types.

[0067] [ka]

[0068] In the above equation (1'), R 1 , R 2 X and n are the same as those exemplified and described in formulas (1) to (3) above, and the preferred embodiments are also the same. When using two or more compounds represented by formula (1') above, multiple R 1 , multiple R 2 The multiple X's and the multiple n's are independent of each other and may be the same or different.

[0069] In the above equation (1'), R 7Each of these independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms. Examples of the above aliphatic hydrocarbon groups having 1 to 3 carbon atoms include linear or branched alkyl groups, linear or branched alkenyl groups, and alkynyl groups. Examples of linear or branched alkyl groups are not particularly limited, but include methyl, ethyl, propyl, and isopropyl groups. Examples of linear or branched alkenyl groups are not particularly limited, but include vinyl, allyl, and propenyl groups. Examples of alkynyl groups are not particularly limited, but include ethynyl and propynyl groups. Among these, R 7 Each of these is preferably a linear or branched alkyl group, R 7 It is more preferable that all of these are linear or branched alkyl groups.

[0070] The step of reacting the surface modifier with the silica particles is preferably carried out in a solvent. Examples of the solvent are not particularly limited, but include water and organic solvents. The solvent may be used alone or in combination of two or more. Examples of organic solvents are not particularly limited, but include the substances exemplified in the description of the step of synthesizing the polyoxyalkylene chain-containing silane coupling agent, alcohols, etc. Examples of alcohols are not particularly limited, but include methanol and ethanol.

[0071] It is preferable to react a mixed solution containing silica particles, a surface modifier, and a solvent in a reaction vessel while stirring. The ratio of silica particles to surface modifier used in the reaction is appropriately selected depending on the desired degree of surface modification. As an example of the ratio of silica particles to surface modifier, it is preferable that the amount of surface modifier used is 0.1 parts by mass or more and 40 parts by mass or less, and more preferably 0.5 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of silica particles.

[0072] The method of mixing silica particles and surface modifiers is not particularly limited, but a method of adding the surface modifier to the silica particles and mixing is preferred. In this case, the silica particles may be added all at once, in portions, or continuously. The stirring speed during mixing is not particularly limited and can be set as appropriate.

[0073] The reaction temperature is preferably 20°C to 200°C, and more preferably 30°C to 150°C. The reaction time is preferably 1 hour to 50 hours, and more preferably 2 hours to 30 hours. The reaction atmosphere may be any of the following, such as an air atmosphere, a nitrogen atmosphere, an argon atmosphere, or other inert gas atmosphere, and is not particularly limited. The pressure during the reaction may also be any of the following, such as normal pressure (atmospheric pressure), pressurized pressure, or reduced pressure, and is not particularly limited. Since the reaction according to the present invention can proceed under normal pressure (atmospheric pressure), it is preferable to carry out the reaction under normal pressure (atmospheric pressure).

[0074] Surface-modified silica particles of component (A) are obtained through a process of synthesizing a polyoxyalkylene chain-containing silane coupling agent and a process of reacting a surface modifier with silica particles.

[0075] If the obtained surface-modified silica particles of component (A) contain a dispersion medium other than water, the dispersion medium other than water may be replaced with water as needed. The method of replacing the dispersion medium other than water with water is not particularly limited, and one example is to add a fixed amount of water dropwise while heating the surface-modified silica particles of component (A). Another example is to separate the surface-modified silica particles of component (A) from the dispersion medium other than water by, for example, a combination of precipitation and separation, and / or centrifugation, and then redisperse them in water.

[0076] The method for producing surface-modified silica particles of component (A) may further include other steps. Examples of other steps include filtering a dispersion containing surface-modified silica particles of component (A), mixing the dispersion containing surface-modified silica particles of component (A) with other additives, and / or filtering the mixture after mixing with other additives.

[0077] (Amount of surface modifier) The degree of modification of the surface-modified silica particles of component (A) can be confirmed using a total organic carbon meter and a centrifuge. Details of this confirmation method are described in the examples.

[0078] (Structure of surface-modified silica particles) The structure of the surface-modified silica particles of component (A) is, for example, 29 This can be confirmed by detecting the T2 component (in the form of formula (2) above) and / or the T3 component (in the form of formula (3) above) using Si-NMR. In this specification, T refers to a Si atom that has three bonds to the O atom and one bond to the polyoxyalkylene chain, and the numbers 2 and 3 refer to the number of Si-O-Si bonds in which the Si atom is involved, respectively. For example, the T2 component refers to a Si atom that has three bonds to the O atom and has two Si atoms involved in Si-O-Si bonds. In unmodified silica particles, the T2 and T3 components bonded to the polyoxyalkylene chain are not detected, but in surface-modified silica particles of component (A), the T2 and T3 components are detected.

[0079] [(B) Component] The water in component (B) is not particularly limited. In one embodiment, component (B) is preferably used as a dispersion medium for dispersing component (A). Component (B) may dissolve and / or disperse components other than component (A). In one embodiment of the polishing composition, a dispersion medium is included, and the dispersion medium preferably includes component (B). In one embodiment of the polishing composition, a dispersion medium is included, and the dispersion medium may consist only of component (B). From the viewpoint of preventing contamination of the object to be polished or interference with the action of other components, it is preferable that the water contains as few impurities as possible. Such water is preferably, for example, water in which the total content of transition metal ions is 100 ppb or less. Here, the purity of the water can be increased by operations such as removal of impurity ions using ion exchange resin, removal of foreign matter by filtration, and distillation. Specifically, preferred examples of water are not particularly limited, but include deionized water (ion-exchanged water), pure water, ultrapure water, and distilled water.

[0080] [(C) component] The polishing composition according to one embodiment may further contain an acid as component (C), or it may not contain an acid as component (C), but it is preferable that it further contains an acid as component (C).

[0081] In one embodiment, component (C) is preferably used as a pH adjuster. The polishing composition according to one embodiment preferably contains a pH adjuster. The polishing composition according to one embodiment contains a pH adjuster, and the pH adjuster preferably contains component (C). The polishing composition according to one embodiment contains a pH adjuster, and the pH adjuster may consist only of component (C).

[0082] The acid in component (C) is not particularly limited. Examples of acids include organic acids and inorganic acids, although they are not particularly limited. Examples of organic acids include aliphatic carboxylic acids, aromatic carboxylic acids, hydroxy acids, organic sulfonic acids, and organic phosphonic acids, although they are not particularly limited. Examples of aliphatic carboxylic acids include aliphatic monocarboxylic acids and aliphatic dicarboxylic acids, although they are not particularly limited. Examples of aliphatic monocarboxylic acids include formic acid, acetic acid, and propionic acid, although they are not particularly limited. Examples of aliphatic dicarboxylic acids include maleic acid, fumaric acid, and succinic acid, although they are not particularly limited. Examples of aromatic carboxylic acids include benzoic acid and phthalic acid, although they are not particularly limited. Examples of hydroxy acids include citric acid, oxalic acid, tartaric acid, and malic acid, although they are not particularly limited. Examples of inorganic acids include sulfuric acid, nitric acid, hydrochloric acid, and carbonic acid, although they are not particularly limited. These acids can be used individually or in combination of two or more. Component (C) preferably contains at least one acid selected from the group consisting of the acids exemplified above. Component (C) is preferably an inorganic acid, and particularly preferably nitric acid. Component (C) may be a commercially available product or a synthetic product.

[0083] The polishing composition according to one embodiment further contains component (C): acid, and it is preferable that the acid contains an inorganic acid. The polishing composition according to one embodiment further contains component (C): acid, and it is more preferable that the acid contains nitric acid. The polishing composition according to one embodiment further contains component (C): acid, and it is even more preferable that the acid consists solely of nitric acid.

[0084] When the polishing composition according to one embodiment contains component (C), the content of component (C) in the polishing composition is not particularly limited. Preferably, the content of component (C) is such that the polishing composition exhibits a desired pH. Preferably, the content of component (C) is 0.00001% by mass or more and 10% by mass or less, more preferably 0.0001% by mass or more and 10% by mass or less, even more preferably 0.001% by mass or more and 1% by mass or less, even more preferably 0.005% by mass or more and 0.5% by mass or less, even more preferably 0.01% by mass or more and 0.25% by mass or less, and particularly preferably 0.01% by mass or more and 0.1% by mass or less, based on the total mass of the polishing composition. When the polishing composition according to one embodiment contains two or more acids as component (C), the content of component (C) represents the total content of these acids.

[0085] [(D) component] The polishing composition according to one embodiment may further contain a compound containing a polyoxyalkylene chain as component (D), or it may not contain a compound containing a polyoxyalkylene chain as component (D), but it is preferable to further contain a compound containing a polyoxyalkylene chain as component (D).

[0086] In this specification, component (D) represents a component that exists in the polishing composition separately from the surface-modifying groups of the surface-modified silica particles of component (A).

[0087] The polyoxyalkylene chain in a compound containing component (D) may consist of only one oxyalkylene or of two or more oxyalkylenes. Examples of polyoxyalkylene chains in a compound containing component (D) are not particularly limited, but include polyoxyethylene chains, polyoxypropylene chains, polyoxytrimethylene chains, polyoxytetramethylene chains, polyoxyisobutylene chains, polyoxyethylene-polyoxypropylene chains, polyoxyethylene-polyoxytetramethylene chains, and polyoxyethylene-polyoxypropylene-polyoxyethylene chains. When the polyoxyalkylene chain in a compound containing component (D) consists of two or more oxyalkylenes, the bonding configuration of the two or more oxyalkylenes may be random, alternating, blocked, periodic, or a combination thereof. The polyoxyalkylene chain in the compound containing the polyoxyalkylene chain of component (D) is preferably at least one polyoxyalkylene chain selected from the group consisting of the polyoxyalkylene chains exemplified above. The polyoxyalkylene chain in the compound containing the polyoxyalkylene chain of component (D) is preferably at least one selected from the group consisting of polyoxyethylene chains, polyoxypropylene chains, polyoxyethylene-polyoxypropylene chains, and polyoxyethylene-polyoxypropylene-polyoxyethylene chains, and is more preferably a polyoxyethylene chain.

[0088] For example, the polyoxyalkylene chain in a compound containing the polyoxyalkylene chain of component (D) may have a structure in which the ends of the polyoxyalkylene chain are sealed. For example, the polyoxyalkylene chain in a compound containing the polyoxyalkylene chain of component (D) may have a structure in which one or both ends of the polyoxyalkylene chain are sealed with an aliphatic hydrocarbon group. That is, the hydrogen atoms in the hydroxyl groups at one or both ends of the polyoxyalkylene chain in a compound containing the polyoxyalkylene chain of component (D) may be substituted with an aliphatic hydrocarbon group. Examples of aliphatic hydrocarbon groups that seal the ends of the polyoxyalkylene chain in a compound containing the polyoxyalkylene chain of component (D) are not particularly limited, but include aliphatic hydrocarbon groups having 1 to 10 carbon atoms. Examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are not particularly limited, but include linear or branched alkyl groups, linear or branched alkenyl groups, alkynyl groups, etc. Examples of linear or branched alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, and decyl groups. Examples of linear or branched alkenyl groups include, but are not limited to, vinyl and allyl groups. Examples of alkynyl groups include ethynyl and propynyl groups.

[0089] In one embodiment, component (D): the compound containing the polyoxyalkylene chain preferably includes a polyalkylene glycol, a compound having a structure in which one end of the polyoxyalkylene chain is sealed, a compound having a structure in which both ends of the polyoxyalkylene chain are sealed, or a combination thereof, and more preferably a polyalkylene glycol, a compound having a structure in which one end of the polyoxyalkylene chain is sealed, a compound having a structure in which both ends of the polyoxyalkylene chain are sealed, or a combination thereof.

[0090] Specific examples of component (D) include, but are not limited to, polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polyisobutylene glycol, ethylene glycol-propylene glycol copolymer, and ethylene glycol-tetramethylene glycol copolymer. The bonding configuration of the copolymer may be random, alternating, block, periodic, or a combination thereof. These compounds containing polyoxyalkylene chains can be used individually or in combination of two or more. Component (D) preferably contains at least one compound containing polyoxyalkylene chain selected from the group consisting of the compounds containing polyoxyalkylene chains exemplified above. Component (D) is preferably polyalkylene glycol, more preferably at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer, and even more preferably polyethylene glycol.

[0091] In one embodiment, the polishing composition further comprises component (D): a compound containing a polyoxyalkylene chain, and it is preferable that the compound containing the polyoxyalkylene chain contains polyalkylene glycol. In one embodiment, the polishing composition further comprises component (D): a compound containing a polyoxyalkylene chain, and it is more preferable that the compound containing the polyoxyalkylene chain contains ethylene glycol. In one embodiment, the polishing composition further comprises component (D): a compound containing a polyoxyalkylene chain, and it is even more preferable that the compound containing the polyoxyalkylene chain consists solely of ethylene glycol.

[0092] The weight-average molecular weight (Mw) of the compound containing the polyoxyalkylene chain of component (D) is not particularly limited. The lower limit of the weight-average molecular weight of the compound containing the polyoxyalkylene chain of component (D) is preferably 80 or more, more preferably 100 or more, even more preferably 200 or more, and particularly preferably 300 or more. The upper limit of the weight-average molecular weight of the compound containing the polyoxyalkylene chain of component (D) is preferably 1,000,000 or less, more preferably 100,000 or less, even more preferably 10,000 or less, and particularly preferably less than 1,000. In one embodiment, examples of weight-average molecular weights of the compound containing the polyoxyalkylene chain of component (D) are not particularly limited, but include 80 to 1,000,000, 100 to 100,000, 200 to 10,000, and 300 to less than 1,000. The weight-average molecular weight of compounds containing polyoxyalkylene chains can be measured by gel permeation chromatography (GPC) using polyethylene glycol as the standard substance.

[0093] (D) Component may be a commercially available product or a synthetic product.

[0094] When the polishing composition according to one embodiment contains component (D), the content of component (D) in the polishing composition is not particularly limited. The content of component (D) is preferably 0.0001% by mass or more and 1% by mass or less, more preferably 0.0005% by mass or more and 0.1% by mass or less, and even more preferably 0.001% by mass or more and 0.01% by mass or less, based on the total mass of the polishing composition. When the polishing composition according to one embodiment contains a compound comprising two or more polyoxyalkylene chains as component (D), the content of component (D) represents the total content of these compounds.

[0095] [(E) component] The polishing composition according to one embodiment may further contain a salt compound as component (E) and may not contain a salt compound as component (D), but it is preferable to further contain a salt compound as component (E).

[0096] In one embodiment, component (E) is preferably used as an electrical conductivity modifier. The polishing composition according to one embodiment preferably contains an electrical conductivity modifier. The polishing composition according to one embodiment contains an electrical conductivity modifier, and the electrical conductivity modifier preferably contains component (E). The polishing composition according to one embodiment contains an electrical conductivity modifier, and the electrical conductivity modifier may consist only of component (E).

[0097] The salt compound may be an acid salt, a base salt, or a combination thereof. The salt compound may be an organic salt compound, an inorganic salt compound, or a combination thereof. Examples of salt compounds, though not particularly limited, include potassium nitrate, ammonium nitrate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium sulfate, potassium chloride, sodium chloride, potassium bromide, potassium iodide, ammonium citrate, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, and tetraethylammonium hydroxide. These salt compounds can be used individually or in combination of two or more. Component (E) preferably contains at least one salt compound selected from the group consisting of the salt compounds exemplified above. Component (E) is preferably an inorganic salt compound, and is particularly preferably ammonium sulfate. Component (E) may be a commercially available product or a synthetic product.

[0098] In one embodiment, the polishing composition further comprises component (E): a salt compound, and it is preferable that the salt compound comprises an inorganic salt compound. In one embodiment, the polishing composition further comprises component (E): a salt compound, and it is more preferable that the salt compound comprises ammonium sulfate. In one embodiment, the polishing composition further comprises component (E): a salt compound, and it is even more preferable that the salt compound consists solely of ammonium sulfate.

[0099] When the polishing composition according to one embodiment contains component (E), the content of component (E) in the polishing composition is not particularly limited. The content of component (E) is preferably 0.01% by mass or more and 7.5% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less, based on the total mass of the polishing composition. When the polishing composition according to one embodiment contains two or more salt compounds as component (E), the content of component (E) represents the total content of these compounds.

[0100] (Other ingredients) An abrasive composition according to one embodiment may further contain one or more other components (excluding components (A) to (E) above) as needed. Therefore, an abrasive composition according to one embodiment may or may not further contain one or more other components. The other components may be known additives that can be used in abrasive compositions. Examples of other components, but are not limited to, include water-soluble polymers (excluding compounds containing polyoxyalkylene chains), pH adjusters (excluding acids), oxidizing agents, complexing agents, preservatives, fungicides, electrical conductivity adjusters (excluding salt compounds), and organic solvents. The substances constituting these other components can each be used independently, individually, or in combination of two or more.

[0101] (Examples of preferred abrasive composition compositions) A polishing composition according to one preferred embodiment may substantially consist of component (A), component (B), and component (C). A polishing composition according to one preferred embodiment may substantially consist of component (A), component (B), component (C), and at least one component selected from the group consisting of component (D) and component (E). A polishing composition according to one preferred embodiment may substantially consist of component (A), component (B), component (C), and at least one component selected from the group consisting of water-soluble polymers (excluding compounds containing polyoxyalkylene chains), pH adjusters (excluding acids), oxidizing agents, complexing agents, preservatives, fungicides, electrical conductivity adjusters (excluding salt compounds), and organic solvents. A polishing composition according to one preferred embodiment may substantially consist of at least one component selected from the group consisting of component (A), component (B), component (C), component (D), and component (E), and at least one component selected from the group consisting of water-soluble polymers (excluding compounds containing polyoxyalkylene chains), pH adjusters (excluding acids), oxidizing agents, complexing agents, preservatives, antifungal agents, electrical conductivity adjusters (excluding salt compounds), and organic solvents. In these embodiments, "the polishing composition is substantially composed of X" means that the total content of X exceeds 99% by mass (upper limit: 100% by mass) of the total mass of the polishing composition. A polishing composition according to one preferred embodiment consists only of X (total content = 100% by mass). A polishing composition according to one preferred embodiment may consist only of component (A), component (B), and component (C). A polishing composition according to one preferred embodiment may consist only of component (A), component (B), component (C), and at least one component selected from the group consisting of component (D) and component (E). A polishing composition according to one preferred embodiment may consist only of component (A), component (B), component (C), and at least one component selected from the group consisting of water-soluble polymers (excluding compounds containing polyoxyalkylene chains), pH adjusters (excluding acids), oxidizing agents, complexing agents, preservatives, fungicides, electrical conductivity adjusters (excluding salt compounds), and organic solvents.A polishing composition according to one preferred embodiment may consist only of at least one component selected from the group consisting of component (A), component (B), component (C), component (D), and component (E), and at least one component selected from the group consisting of water-soluble polymers (excluding compounds containing polyoxyalkylene chains), pH adjusters (excluding acids), oxidizing agents, complexing agents, preservatives, fungicides, electrical conductivity adjusters (excluding salt compounds), and organic solvents. However, the polishing composition according to this embodiment is not limited to these.

[0102] (pH of the abrasive composition) The pH of the polishing composition according to one embodiment is not particularly limited as long as it is less than 7. From the viewpoint that the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material tends to be in a better range, the upper limit of the pH of the polishing composition according to one embodiment is preferably 6 or less, and more preferably less than 6. From the viewpoint that the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the nitrogen-silicon bond material tends to be in a better range, the upper limit of the pH of the polishing composition according to one embodiment is even more preferably 5 or less, even more preferably 4 or less, and particularly preferably 3 or less. From the viewpoint that the polishing rate of the silicon-silicon bond material tends to be further improved, the lower limit of the pH of the polishing composition according to one embodiment is preferably 1 or more, more preferably 1.5 or more, and even more preferably 2 or more. Examples of pH ranges for the polishing composition according to one embodiment include, but are not limited to, 1 to less than 7, 1 to less than 6, 1 to 6 or less, 1 to 5 or less, 1 to 4 or less, 1 to 3 or less, 1.5 to less than 7, 1.5 to less than 6, 1.5 to 6 or less, 1.5 to 5 or less, 1.5 to 4 or less, 1.5 to 3 or less, 2 to less than 7, 2 to 6 or less, 2 to 5 or less, 2 to 4 or less, and 2 to 3 or less. The pH value of the polishing composition can be confirmed using a pH meter. Detailed methods for measuring pH are described in the examples.

[0103] (Electrical conductivity of abrasive compositions) The electrical conductivity of the polishing composition according to one embodiment is not particularly limited. The electrical conductivity of the polishing composition according to one embodiment is preferably 0.1 mS / cm or more, more preferably 0.5 mS / cm or more, even more preferably 1 mS / cm or more, even more preferably 1.5 mS / cm or more, and particularly preferably 2 mS / cm or more. Furthermore, the electrical conductivity is preferably 20 mS / cm or less, more preferably 15 mS / cm or less, even more preferably 10 mS / cm or less, even more preferably 8 mS / cm or less, even more preferably 6 mS / cm or less, and particularly preferably 4 mS / cm or less. For example, it may be 3.5 mS / cm or less, or for example, 2 mS / cm or less. Within these ranges, the repulsion between abrasive grains can be appropriately adjusted and stability can be ensured. Examples of the range of electrical conductivity of the polishing composition according to one embodiment are not particularly limited, but include 0.1 mS / cm to 20 mS / cm, 0.5 mS / cm to 15 mS / cm, 0.5 mS / cm to 10 mS / cm, 1 mS / cm to 10 mS / cm, 1.5 mS / cm to 8 mS / cm, 2 mS / cm to 6 mS / cm, 2 mS / cm to 4 mS / cm, 2 mS / cm to 3.5 mS / cm, greater than 0 mS / cm and 3.5 mS / cm, greater than 0 mS / cm and 2.0 mS / cm. The electrical conductivity of the polishing composition can be measured using an electrical conductivity meter. Detailed methods for measuring electrical conductivity are described in the examples. Electrical conductivity can be adjusted depending on the type and content of the polishing composition, for example, by the type and content of the electrical conductivity adjusting agent.

[0104] (Form of abrasive composition) The polishing composition according to one embodiment may be a one-component type or a multi-component type consisting of two or more components. The polishing composition according to one embodiment may be used for polishing as is. The polishing composition according to one embodiment may be obtained, for example, by a method including adding component (B) to a concentrated solution of the polishing composition, or by adding an additional amount of component (B) to dilute it. The polishing composition according to one embodiment may be, for example, a concentrated solution of the polishing composition.

[0105] (Method for producing abrasive compositions) The method for producing the polishing composition according to one embodiment is not particularly limited. An example of a method for producing the polishing composition according to one embodiment is a method that includes mixing component (A), component (B), optionally component (C), optionally component (D), optionally component (E), and optionally one or more other components. The method for producing the polishing composition according to one embodiment is preferably a method that includes producing component (A) by the method for producing surface-modified silica particles (preferably the method of (a1) or (b1), more preferably the method of (a1)), and mixing component (A), component (B), optionally component (C), optionally component (D), optionally component (E), and optionally one or more other components.

[0106] (Object to be polished) The object to be polished using the polishing composition according to one embodiment is not particularly limited. The object to be polished may consist of only one type of material, or it may be a combination of two or more types of materials. The polishing composition according to one embodiment is preferably used to polish an object containing at least one material selected from the group consisting of materials having silicon-silicon bonds, materials having oxygen-silicon bonds, and materials having nitrogen-silicon bonds. In addition to at least one material selected from the group consisting of materials having silicon-silicon bonds, materials having oxygen-silicon bonds, and materials having nitrogen-silicon bonds, the object to be polished may further contain one or more other materials. Examples of other materials are not particularly limited, but include metals and resins. The polishing composition according to one embodiment is preferably used for polishing an object containing materials having oxygen-silicon bonds and materials having silicon-silicon bonds. For example, the polishing composition according to one embodiment is preferably used for polishing an object containing a layer having oxygen-silicon bonds and a layer having silicon-silicon bonds. A polishing composition according to one embodiment may be used to polish objects containing materials having oxygen-silicon bonds, materials having nitrogen-silicon bonds, and materials having silicon-silicon bonds. For example, a polishing composition according to one embodiment may be used to polish objects containing layers having oxygen-silicon bonds, layers having nitrogen-silicon bonds, and layers having silicon-silicon bonds. A polishing composition according to one embodiment may be used to polish objects containing materials having silicon-silicon bonds, noting the effect of achieving a high polishing speed for materials having silicon-silicon bonds. A polishing composition according to one embodiment may be used to polish objects containing materials having nitrogen-silicon bonds, materials having silicon-silicon bonds, or combinations thereof.

[0107] Examples of materials having silicon-silicon bonds include, but are not limited to, single-crystal silicon, polycrystalline silicon (polysilicon), amorphous silicon, n-type doped single-crystal silicon, p-type doped single-crystal silicon, and Si-based alloys. Examples of materials having oxygen-silicon bonds include, but are not limited to, silicon oxide. Examples of materials having oxygen-silicon bonds include, but are not limited to, TEOS-type silicon oxide (also simply referred to as "TEOS" in this specification) produced using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma), USG (Undoped Silicate Glass), PSG (Phosphorus Silicate Glass), BPSG (Boron-Phospho Silicate Glass), and RTO (RaPID Thermal Oxidation). Examples of materials having nitrogen-silicon bonds include, but are not limited to, silicon nitride and silicon carbonitride (SiCN). These materials can be used individually or in combination of two or more. The object to be polished preferably contains at least one material selected from the group consisting of the materials exemplified above. The object to be polished preferably contains polysilicon, more preferably contains silicon dioxide and polysilicon, and even more preferably contains TEOS and polysilicon. The object to be polished may also contain silicon dioxide, silicon nitride and polysilicon, or may contain TEOS, silicon nitride and polysilicon.

[0108] The ratio of the polishing speed of a silicon-silicon bond material (preferably polysilicon; hereinafter the same applies in this paragraph) to the polishing speed of an oxygen-silicon bond material (preferably silicon oxide, more preferably TEOS; hereinafter the same applies in this paragraph) (polishing speed of silicon-silicon bond material / polishing speed of oxygen-silicon bond material) is not particularly limited. In one embodiment, the polishing composition preferably has the characteristic that the ratio of the polishing speed of the silicon-silicon bond material to the polishing speed of the oxygen-silicon bond material is 0.50 or more and 2.00 or less. The ratio of the polishing speed of the silicon-silicon bond material to the polishing speed of the oxygen-silicon bond material is more preferably 0.80 or more and 1.90 or less, and even more preferably 0.90 or more and 1.90 or less. It may be preferable that the polishing speed of the silicon-silicon bond material is the same as or slightly greater than the polishing speed of the oxygen-silicon bond material. The ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material is more preferably 1.00 to 1.80, more preferably 1.10 to 1.70, more preferably 1.20 to 1.60, more preferably 1.20 to 1.50, and particularly preferably 1.30 to 1.50.

[0109] The ratio of the polishing rate of a silicon-silicon bond material (preferably polysilicon; hereinafter the same applies in this paragraph) to the polishing rate of a nitrogen-silicon bond material (preferably silicon nitride; hereinafter the same applies in this paragraph) (polishing rate of silicon-silicon bond material / polishing rate of nitrogen-silicon bond material) is not particularly limited. In one embodiment, it may be preferable that the polishing rate of the silicon-silicon bond material is greater than the polishing rate of the nitrogen-silicon bond material, but not excessively so. The ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the nitrogen-silicon bond material is preferably 2.50 or more and 10.00 or less. The ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the nitrogen-silicon bond material is more preferably 2.50 to 9.00, even more preferably 3.00 to 8.50, even more preferably 3.00 to 8.00, even more preferably 4.00 to 7.50, even more preferably 5.00 to 7.50, even more preferably 6.00 to 7.00, and particularly preferably 6.20 to 6.80.

[0110] <Polishing method and method for manufacturing semiconductor substrates> Another aspect of the present invention relates to a polishing method, which includes polishing an object to be polished using the polishing composition according to the above aspect.

[0111] According to a polishing method of one embodiment of the present invention, which includes such a configuration, when the pH of the polishing composition is less than 7, it is possible to achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having silicon-silicon bonds to the polishing rate of materials having oxygen-silicon bonds.

[0112] The object to be polished in this embodiment is also the same as described for the object to be polished to which the polishing composition according to the above embodiment is applied.

[0113] In a polishing method according to one embodiment, the object to be polished preferably includes a material having oxygen-silicon bonds and a material having silicon-silicon bonds. For example, in a polishing method according to one embodiment, the object to be polished preferably includes a layer having oxygen-silicon bonds and a layer having silicon-silicon bonds. In a polishing method according to one embodiment, the object to be polished may include a material having oxygen-silicon bonds, a material having nitrogen-silicon bonds, and a material having silicon-silicon bonds. For example, in a polishing method according to one embodiment, the object to be polished may include a layer having oxygen-silicon bonds, a layer having nitrogen-silicon bonds, and a layer having silicon-silicon bonds. In a polishing method according to one embodiment, with regard to the effect that a high polishing speed of silicon-silicon bonded materials is achieved by the polishing composition according to the above embodiment, the object to be polished may include a material having silicon-silicon bonds. In a polishing method according to one embodiment, the object to be polished may include a material having nitrogen-silicon bonds, a material having silicon-silicon bonds, or a combination thereof. Examples of materials having silicon-silicon bonds, oxygen-silicon bonds, and nitrogen-silicon bonds are the same as those exemplified in the description of the object to be polished above. In a polishing method according to one preferred embodiment, the object to be polished preferably contains polysilicon, more preferably silicon oxide and polysilicon, and even more preferably TEOS and polysilicon. In a polishing method according to one embodiment, the object to be polished may contain silicon oxide, silicon nitride and polysilicon, or may contain TEOS, silicon nitride and polysilicon.

[0114] The ratio of the polishing rate of a silicon-silicon bond material (preferably polysilicon; hereinafter the same applies in this paragraph) to the polishing rate of an oxygen-silicon bond material (preferably silicon oxide, more preferably TEOS; hereinafter the same applies in this paragraph) (polishing rate of the silicon-silicon bond material / polishing rate of the oxygen-silicon bond material) is not particularly limited. In one embodiment of the polishing method, it is preferable that the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material is 0.50 or more and 2.00 or less. It is preferable that the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material is 0.80 or more and 1.90 or less, and more preferably 0.90 or more and 1.90 or less. It may be preferable that the polishing rate of the silicon-silicon bond material is the same as or slightly greater than the polishing rate of the oxygen-silicon bond material. The ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material is more preferably 1.00 or more and 1.80 or less, more preferably 1.10 or more and 1.80 or less, more preferably 1.10 or more and 1.70 or less, more preferably 1.20 or more and 1.60 or less, more preferably 1.20 or more and 1.50 or less, and particularly preferably 1.30 or more and 1.50 or less.

[0115] The ratio of the polishing rate of a silicon-silicon bond material (preferably polysilicon; hereinafter the same applies in this paragraph) to the polishing rate of a nitrogen-silicon bond material (preferably silicon nitride; hereinafter the same applies in this paragraph) (polishing rate of silicon-silicon bond material / polishing rate of nitrogen-silicon bond material) is not particularly limited. It may be preferable that the polishing rate of the silicon-silicon bond material is greater than the polishing rate of the nitrogen-silicon bond material, but not excessively so. In the polishing method of one embodiment, the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the nitrogen-silicon bond material is preferably 2.50 or more and 10.00 or less, more preferably 2.50 or more and 9.00 or less, even more preferably 3.00 or more and 8.50 or less, even more preferably 3.00 or more and 8.00 or less, even more preferably 4.00 or more and 7.50 or less, even more preferably 5.00 or more and 7.50 or less, even more preferably 6.00 or more and 7.00 or less, and particularly preferably 6.20 or more and 6.80 or less.

[0116] Another further aspect of the present invention relates to a method for manufacturing a semiconductor substrate, wherein the semiconductor substrate includes an object to be polished, and the method includes polishing the object to be polished by the polishing method according to the above aspect. The object to be polished in this aspect is also the same as described for the object to which the polishing composition according to the above aspect is applied.

[0117] The polishing apparatus is not particularly limited, but an example of a polishing apparatus that can be used is a general polishing apparatus that has a holder for holding a substrate or the like containing the object to be polished, a motor with a changeable rotation speed, and a polishing platen to which a polishing pad (abrasive cloth) can be attached.

[0118] The polishing pad is not particularly limited. Examples of materials for the polishing pad are not particularly limited, but include nonwoven fabrics, polyurethanes, and porous fluororesins. It is preferable that the polishing pad has grooves that allow the polishing liquid to accumulate.

[0119] The polishing conditions are not particularly limited. For example, the rotational speed (rotational speed) of the polishing platen may be 10 rpm (0.17 s). -1 ) or more 500rpm (8.33s -1 Preferably, the rotational speed (rotational speed) of the head is 10 rpm (0.17 s). -1 ) or more 500rpm (8.33s -1 Preferably, the pressure applied to the substrate having the object to be polished (polishing pressure) is between 0.5 psi (3.4 kPa) and 10 psi (68.9 kPa). The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying it with a pump or the like can be employed. There is no limit to the amount supplied, but it is preferable that the surface of the polishing pad is always covered with the polishing composition. The polishing time is also not particularly limited, and for example, a time that can achieve the desired polishing can be appropriately selected.

[0120] After polishing is complete, the substrate containing the polished object may be washed with running water, and any water droplets adhering to the substrate may be removed and dried using a spin dryer or similar device.

[0121] While embodiments of the present invention have been described in detail, these are descriptive and illustrative, and not limiting, and it is clear that the scope of the present invention should be interpreted by the appended claims.

[0122] The present invention includes, but is not limited to, the following embodiments and forms: [1] A polishing composition comprising the following components (A) and (B), with a pH of less than 7; (A) Component: Surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which modifies the surface of the silica particles; (B) Ingredient: water; [2] The polishing composition according to [1] above, wherein the weight-average molecular weight of the polyoxyalkylene chain is 80 or more and 600 or less; [3] The polishing composition according to [1] or [2] above, wherein component (A) comprises silica particles on which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent; [4] The polishing composition according to [3] above, wherein the compound containing the polyoxyalkylene chain is a compound consisting solely of polyalkylene glycol chains; [5] The polishing composition according to [4] above, wherein the compound consisting solely of polyalkylene glycol chains is at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer; [6] The silane coupling agent is an abrasive composition according to any one of [3] to [5] above, comprising an isocyanate group-containing silane coupling agent; [7] The polishing composition according to any one of [1] to [6] above, wherein the pH is 1 or more and less than 6; [8] An abrasive composition according to any of [1] to [7] above, having an electrical conductivity of 0.5 mS / cm or more and 10 mS / cm or less; [9] A polishing composition according to any one of [1] to [8] above, having the characteristic that the ratio of the polishing rate of a material having a silicon-silicon bond to the polishing rate of a material having an oxygen-silicon bond (polishing rate of the material having a silicon-silicon bond / polishing rate of the material having an oxygen-silicon bond) is 0.50 or more and 2.00 or less;

[10] Polishing compositions according to any one of [1] to [9] above, used for polishing objects containing materials having oxygen-silicon bonds and materials having silicon-silicon bonds;

[11] A polishing method for polishing an object to be polished, which includes an oxygen-silicon bond and a silicon-silicon bond, using the polishing composition described in any of [1] to

[10] above;

[12] The polishing method according to

[11] above, wherein the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material (polishing rate of the silicon-silicon bond material / polishing rate of the oxygen-silicon bond material) is 0.50 or more and 2.00 or less. [Examples]

[0123] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively.

[0124] <Manufacturing of surface-modified silica particles> (Manufacturing Example 1) 36.3 g of polyethylene glycol 1 was placed in a 100 mL sealed heat-resistant container, and the container was placed on an 80°C hot stirrer. The lid was removed, and the mixture was stirred at 100 rpm using a stirring bar. During stirring, 18.7 g of 3-isocyanatetopropyltrimethoxysilane was added at a rate of 0.03 g / sec so that the molar ratio of polyethylene glycol 1 to 3-isocyanatetopropyltrimethoxysilane was 1:1. After adding the 3-isocyanatetopropyltrimethoxysilane, the container was sealed, and stirring continued at 100 rpm for another 30 minutes. The stirring bar was removed, the container was sealed again, and returned to an air bath in an 80°C atmosphere. The FT-IR spectrum was measured at 2,260 cm⁻¹. -1 The mixture was heated until the peaks of isocyanate groups derived from the nearby silane coupling agent disappeared. This heating process was carried out for a total of 26 hours to obtain the target surface modifier 1.

[0125] Separately, 4,500 g of a 5% by mass high-purity colloidal silica aqueous solution (average secondary particle size: 70 nm, synthesized by the sol-gel method) was placed in a 5,000 mL flask and heated to 80°C using a mantle heater. After reaching 80°C, 50.8 g of the surface modifier 1 obtained above was weighed and added at a rate of 0.03 g / sec while stirring the solution at 150 rpm. Furthermore, while maintaining the liquid temperature at 80°C using a mantle heater, the mixture was stirred at 150 rpm for 30 minutes. After that, it was transferred to a sealed container, sealed, and returned to an air bath with an 80°C atmosphere, where it was heated for 26 hours to obtain the target surface-modified colloidal silica 1.

[0126] (Manufacturing Examples 2-9) In Example 1 described above, the target surface-modified colloidal silicas 2 to 9 were obtained in the same manner, except that polyethylene glycol 1 was replaced with ethylene glycol, polyethylene glycol 2, polyethylene glycol 3, polyethylene glycol 4, polyethylene glycol 5, polyethylene glycol 6, polyethylene glycol 7, or polyethylene glycol 8, as shown in Table 1.

[0127] Details of the surface-modified colloidal silica and the alkylene glycol or polyoxyalkylene chain compounds used in its production are shown in Table 1.

[0128] (Average secondary particle diameter of silica particles) The average secondary particle size of silica particles was evaluated by measuring a 5% by mass high-purity colloidal silica aqueous solution using dynamic light scattering methods, such as laser diffraction scattering.

[0129] (Confirmation of the structure of the surface modifier) The surface modifier 1 obtained above was structurally confirmed using the following FT-IR apparatus: Equipment used: Fourier transform infrared spectrometer (Spectrum100, PerkinElmer) Detection method: ATR (Attenuated Total Reflection) method.

[0130] Specifically, 1 g of the 3-isocyanate-propyltrimethoxysilane from Production Example 1 was sampled from the reaction system 10 minutes after it was added. The obtained sample was placed on the ATR measurement crystal of Spectrum100 and the FT-IR spectrum was measured. The result was 2,260 cm⁻¹. -1 We were able to confirm the presence of isocyanate groups derived from silane coupling agents in the vicinity.

[0131] Furthermore, 1 g was sampled from the reaction system once the reaction was complete. The obtained sample was placed on an ATR crystal of Spectrum100 and its FT-IR spectrum was measured. The result was 2,260 cm⁻¹. -1 In the vicinity, we were able to confirm the disappearance of the peak of the isocyanate group derived from the silane coupling agent. This confirmed that surface modifier 1, in which a compound containing a polyoxyalkylene chain and the silane coupling agent are bonded, has been formed.

[0132] Furthermore, using an FT-IR instrument, it can be confirmed that surface modifiers 2 to 9 obtained in the above production examples 2 to 9 also produce surface modifier 2, which is a compound of alkylene glycol and a silane coupling agent, and surface modifiers 3 to 9, which are compound of a polyoxyalkylene chain and a silane coupling agent, respectively.

[0133] (Amount of surface modifier applied to surface-modified colloidal silica) The amount of surface modification agent was confirmed for the surface-modified colloidal silica 1 obtained above using the total organic carbon meter and centrifuge described below. Specifically, a dilution was prepared by diluting the surface-modified colloidal silica 1 with water to a silica concentration of 0.175 mass%, and the TOC value was calculated by subtracting the TOC value of the supernatant after centrifugation from the TOC value of this dilution (i.e., calculating the TOC value of the dilution minus the TOC value of the supernatant after centrifugation). As a result, it was confirmed that the colloidal silica was modified by 8.4 mass% of surface modifier 1 relative to the mass of silica.

[0134] Furthermore, the amount of surface modification agent in surface-modified colloidal silica 2-9 obtained above can be confirmed in the same manner using the total organic carbon analyzer and centrifuge described below.

[0135] Total Organic Carbon Dioxide Meter Equipment used: TOC-L CPH (Manufactured by Shimadzu Corporation) Measurement method: 680°C combustion catalyst oxidation / NDIR detection.

[0136] ≪Centrifugal separator≫ Equipment used: Avanti HP-30I (manufactured by Beckman Coulter) Rotational speed: 26,000 rpm, Centrifugation time: 30 minutes.

[0137] Furthermore, the structure of surface-modified colloidal silica 29 By using Si-NMR, it can be confirmed that the desired surface-modified colloidal silica is obtained using the manufacturing method described in the example.

[0138] [Table 1]

[0139] <Manufacturing of abrasive compositions> (Examples 1-10 and Comparative Examples 1-4) As shown in Table 2, the polishing compositions of Examples 1-10 and Comparative Examples 1-5 were obtained by mixing silica particles, an acid or base, water, a compound containing an oxyalkylene chain if necessary, and a salt compound if necessary.

[0140] In Table 2, "unmodified colloidal silica" refers to colloidal silica (average secondary particle size: 70 nm, synthesized by the sol-gel method). The unmodified colloidal silica used is the same as the colloidal silica used as a raw material for the surface-modified silica particles in the production of the surface-modified silica particles described above. In Table 2, "polyethylene glycol 1" refers to the same type of polyethylene glycol used in the production of the surface-modified colloidal silica.

[0141] Table 2 shows the content of silica particles, acids or bases, compounds containing polyoxyalkylene chains, and salt compounds, each expressed as a mass %) relative to the total mass of the polishing composition.

[0142] In Table 2, a "-" in the Type and Content column indicates that the ingredient was not added.

[0143] <Evaluation of abrasive compositions> (pH of the abrasive composition) The pH of the polishing composition was confirmed using a pH meter (manufactured by Horiba, Ltd., product name: LAQUA®).

[0144] (Electrical conductivity of abrasive compositions) The electrical conductivity (EC) of the polishing composition was measured using a benchtop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71 LAQUA®).

[0145] (polishing performance) The surface of the object to be polished was polished using a polishing composition under the following polishing conditions. In this evaluation, the following silicon wafers were used as objects to be polished: a silicon wafer (300 mm, blanket wafer) with a 5,000 Å thick polysilicon (Poly-Si) film formed on its surface; a silicon wafer (300 mm, blanket wafer) with a 10,000 Å thick P-TEOS film (TEOS film (silicon dioxide film) formed by plasma CVD) formed on its surface; and a silicon wafer (300 mm, blanket wafer) with a 3,000 Å thick silicon nitride (SiN) film formed on its surface.

[0146] ≪Polishing conditions≫ Polishing equipment: Applied Materials Mirra CMP single-sided polishing machine for 200mm Polishing pad: Nitta Haas Co., Ltd. Hard polyurethane pad IC1010 Polishing pressure: 2.0 psi Polishing plate rotation speed: 63 rpm Head (carrier) rotation speed: 57 rpm Supply of polishing composition: flow-through Polishing composition supply amount: 100mL / min Polishing time: 60 seconds.

[0147] The polishing speed was determined by measuring the thickness using an optical film thickness gauge (RE-3500: manufactured by SCREEN Corporation), and then dividing (thickness before polishing) - (thickness after polishing) by the polishing time. The ratio of the polishing speed of the polysilicon film (Å / min) to the polishing speed of the P-TEOS film (Å / min) (polishing speed of polysilicon film / polishing speed of P-TEOS film) was calculated as the selection ratio. Similarly, the ratio of the polishing speed of the polysilicon film (Å / min) to the polishing speed of the silicon nitride film (polishing speed of polysilicon film / polishing speed of silicon nitride film) was also calculated as the selection ratio.

[0148] Table 3 shows the polishing speeds (Å / min) for polysilicon (Poly-Si) film, P-TEOS film, and silicon nitride (SiN) film obtained from the above evaluation. Table 3 also shows the selectivity ratio (ratio of polishing speeds) calculated from these polishing speeds. In Table 3, the ratio of the polishing speed of polysilicon to that of P-TEOS (polysilicon polishing speed / P-TEOS polishing speed) is denoted as Poly-Si / P-TEOS, and the ratio of the polishing speed of polysilicon to that of silicon nitride (polysilicon polishing speed / silicon nitride polishing speed) is denoted as Poly-Si / SiN.

[0149] In Table 3, an evaluation item marked with "-" indicates that the evaluation was not performed. Note that the polishing properties of the polishing composition in Comparative Example 3 were not evaluated because aggregation occurred.

[0150] In this evaluation, a higher polishing speed for polysilicon is preferable.

[0151] In this evaluation, the ratio of the polishing speed of the polysilicon film to the polishing speed of the P-TEOS film is preferably 0.50 or more and 2.00 or less, more preferably 0.80 or more and 1.90 or less, even more preferably 0.90 or more and 1.90 or less, even more preferably 1.00 or more and 1.80 or less, even more preferably 1.10 or more and 1.80 or less, even more preferably 1.10 or more and 1.70 or less, even more preferably 1.20 or more and 1.60 or less, even more preferably 1.20 or more and 1.50 or less, and particularly preferably 1.30 or more and 1.50 or less.

[0152] In this evaluation, the ratio of the polishing rate of the polysilicon film to the polishing rate of the silicon nitride film is not particularly limited. However, in this evaluation, the ratio of the polishing rate of the polysilicon film to the polishing rate of the silicon nitride film is preferably 2.50 or more and 10.00 or less, more preferably 2.50 or more and 9.00 or less, even more preferably 3.00 or more and 8.50 or less, even more preferably 3.00 or more and 8.00 or less, even more preferably 4.00 or more and 7.50 or less, even more preferably 5.00 or more and 7.50 or less, even more preferably 6.00 or more and 7.00 or less, and particularly preferably 6.20 or more and 6.80 or less.

[0153] [Table 2]

[0154] [Table 3]

[0155] From the results of Comparative Example 1 and Examples 1-10, it was confirmed that a polishing composition comprising surface-modified silica particles containing surface-modifying groups including polyoxyalkylene chains having a specific weight-average molecular weight, and water, can achieve a high polishing rate for materials having silicon-silicon bonds while maintaining a good ratio of the polishing rate of materials having oxygen-silicon bonds to the polishing rate of materials having silicon-silicon bonds.

[0156] The results from Example 4 and Comparative Example 4 confirmed that the effects of the present invention cannot be obtained if the polishing composition merely contains a compound containing a polyoxyalkylene chain, but the effects of the present invention can be obtained when the polishing composition contains surface-modified silica particles containing a surface-modifying group that includes a polyoxyalkylene chain having a specific weight-average molecular weight.

[0157] From the results of Examples 4 and 9, and Comparative Example 5, it was confirmed that the effects of the present invention are obtained when the pH of the polishing composition is less than 7, for example, when the pH is 2.2 as in Example 4, and for example, when the pH is 5.2 as in Example 9. On the other hand, the effects of the present invention are not obtained when the pH of the polishing composition is high, for example, when the pH is 8.1 as in Comparative Example 5.

Claims

1. A polishing composition comprising the following components (A) and (B), with a pH of less than 7; (A) Components: Surface-modified silica particles comprising silica particles and a surface-modifying group containing a polyoxyalkylene chain having a weight-average molecular weight of 80 to 7,000, which surface-modifies the silica particles; (B) Component: Water.

2. The polishing composition according to claim 1, wherein the weight-average molecular weight of the polyoxyalkylene chain is 80 or more and 600 or less.

3. The polishing composition according to claim 1, wherein component (A) comprises silica particles on which a compound containing a polyoxyalkylene chain is immobilized on the surface of the particles via a silane coupling agent.

4. The polishing composition according to claim 3, wherein the compound containing the polyoxyalkylene chain is a compound consisting solely of polyalkylene glycol chains.

5. The polishing composition according to claim 4, wherein the compound consisting solely of polyalkylene glycol chains is at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and polyethylene glycol-polypropylene glycol copolymer.

6. The polishing composition according to claim 3, wherein the silane coupling agent comprises an isocyanate group-containing silane coupling agent.

7. The polishing composition according to claim 1, wherein the pH is 1 or more and less than 6.

8. The polishing composition according to claim 1, wherein the electrical conductivity is 0.5 mS / cm or more and 10 mS / cm or less.

9. The polishing composition according to claim 1, having the characteristic that the ratio of the polishing rate of a material having a silicon-silicon bond to the polishing rate of a material having an oxygen-silicon bond is 0.50 or more and 2.00 or less.

10. The polishing composition according to claim 1, used for polishing objects containing materials having oxygen-silicon bonds and materials having silicon-silicon bonds.

11. A polishing method for polishing an object to be polished, which includes a material having an oxygen-silicon bond and a material having a silicon-silicon bond, using the polishing composition according to any one of claims 1 to 10.

12. The polishing method according to claim 11, wherein the ratio of the polishing rate of the silicon-silicon bond material to the polishing rate of the oxygen-silicon bond material is 0.50 or more and 2.00 or less.

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