Grinding composition

Abstract

To provide a new polishing composition capable of polishing a material including silicon atoms at a high speed and to provide a new polishing composition capable of polishing a material including silicon atoms, TiN and the like at a high speed.SOLUTION: A polishing composition includes: abrasive grains; a polishing rate improver of an object to be polished including silicon atoms; and a liquid carrier. The abrasive grains have a surface modified with cations, and the polishing rate improver includes α-keto acid.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polishing composition. [Background technology]

[0002] The high integration brought about by the miniaturization of LSI manufacturing processes has led to the achievement of high performance in electronic devices such as computers, which have become smaller, more multifunctional, and faster. Chemical mechanical polishing (CMP) is used as a new microfabrication technology for the high integration of LSIs.

[0003] CMP has been applied to various steps in semiconductor manufacturing. In one embodiment, CMP is used to polish materials containing titanium atoms, such as TiN, and materials containing silicon atoms, such as single crystal silicon, polycrystalline silicon, silicon oxide, and silicon nitride, and it is necessary to control the polishing rate of each material.

[0004] For example, Patent Document 1 discloses an aqueous chemical mechanical polishing composition containing a salt, soluble cerium, a carboxylic acid, and silica (particularly fumed silica) as a CMP slurry for polishing a substrate containing silicon atoms. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2001-507739 Summary of the Invention [Problem to be solved by the invention]

[0006] In a situation where there is a demand to control the polishing rate of each material, an objective of the present invention is to provide a novel polishing composition capable of polishing materials containing silicon atoms at high speed. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research and have found that the above problems can be solved by a polishing composition that includes abrasive grains, a polishing rate enhancer for an object to be polished that contains silicon atoms, and a liquid carrier, the abrasive grains having surfaces that are cationically modified, and the polishing rate enhancer that contains an alpha-keto acid. Effect of the Invention

[0008] The present invention can provide a novel polishing composition capable of polishing materials containing silicon atoms at high speed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below. The present invention is not limited to the following embodiments. Unless otherwise specified, the operation and measurement of physical properties are performed under the conditions of room temperature (20 to 25°C) and relative humidity 40 to 50% RH. It should be understood that all combinations of lower and upper limits disclosed in this specification are disclosed. In other words, it should be understood that they can be the basis for correction.

[0010] <Polishing composition> In one embodiment of the present invention, there is provided a polishing composition comprising an abrasive grain, a polishing rate enhancer for a polishing object containing silicon atoms, and a liquid carrier, the abrasive grain having a surface cationically modified, and the polishing rate enhancer containing an alpha-keto acid. According to this embodiment, a novel polishing composition capable of polishing a material containing silicon atoms at high speed can be provided.

[0011] Each component constituting the polishing composition will be described below.

[0012] [Abrasive grain] In one embodiment of the present invention, the polishing composition contains abrasive grains, and the surfaces of the abrasive grains are cationically modified. If the abrasive grains having the surfaces cationically modified are not used, there is a risk that the intended effect of the present invention will not be achieved.

[0013] In one embodiment of the invention, the modification is by chemical bonding.

[0014] In one embodiment of the present invention, the specific example of the abrasive grain may be any of inorganic particles, organic particles, and organic-inorganic composite particles, but is preferably inorganic particles.Specific examples of the inorganic particles include particles made of metal oxides such as silica, alumina, ceria, and titania, silicon nitride particles, silicon carbide particles, and boron nitride particles.In one embodiment of the present invention, the abrasive grain is an abrasive grain other than ceria.In one embodiment of the present invention, the abrasive grain is silica.As the silica, fumed silica and colloidal silica are preferred, and colloidal silica is particularly preferred.Methods for producing colloidal silica include the sodium silicate method and the sol-gel method.

[0015] In one embodiment of the present invention, the surface of the abrasive grain is cationically modified. In one embodiment of the present invention, the colloidal silica having a cationically modified surface is preferably a colloidal silica having an amino group or a quaternary ammonium group fixed to the surface. As a method for producing colloidal silica having such a cationic group, as described in JP-A-2005-162533, a method of fixing a silane coupling agent having an amino group such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, or a silane coupling agent having a quaternary ammonium group such as N-trimethoxysilylpropyl-N,N,N-trimethylammonium to the surface of the abrasive grain can be mentioned. This makes it possible to obtain colloidal silica having an amino group or a quaternary ammonium group fixed to the surface of the abrasive grain. In one embodiment of the present invention, the abrasive grain is obtained by fixing a silane coupling agent having an amino group or a silane coupling agent having a quaternary ammonium group to the surface of the abrasive grain.

[0016] In one embodiment of the present invention, the number of silanol groups per unit surface area of ​​the abrasive grains (silanol group density) is 2.0 / nm 2 In one embodiment of the present invention, the number of silanol groups is greater than 2.1 / nm 2 More than 2.3 pieces / nm 2 More than 2.5 pieces / nm 2 More than 2.7 pieces / nm 2 More than 2.9 pieces / nm 2 More than 3.1 pieces / nm 2 More than 3.3 pieces / nm 2 or more than 3.5 / nm 2 That is all. By having such a lower limit, the desired effect of the present invention can be efficiently achieved. In one embodiment of the present invention, the number of silanol groups per unit surface area of ​​the abrasive grains (silanol group density) is 10 / nm 2 Less than 8 pieces / nm 2 Below, 6 pieces / nm 2 Below, 5 pieces / nm 2 or less than 4 / nm 2 The upper limit is as follows. By setting such an upper limit, the technical effect of the present invention is that the desired effect of the present invention can be efficiently achieved.

[0017] In one embodiment of the present invention, the number of silanol groups per unit surface area of ​​the abrasive grain is 2.0 / nm 2 In order to achieve a silanol group density of 2.0 / nm2 or less per unit surface area of ​​the abrasive grains, for example, a method for appropriately selecting a manufacturing method for the abrasive grains may be used. 2 If there is a commercially available product that is ultra-low-temperature, you can purchase that.

[0018] In one embodiment of the present invention, the silanol group density can be calculated by the following method after measuring or calculating each parameter by the following measurement method or calculation method.

[0019] In the formula below, C is the total mass of the abrasive grains, and S is the BET specific surface area of ​​the abrasive grains. First, 1.50 g of abrasive grains as solid content is collected in a 200 ml beaker, 100 ml of pure water is added to make a slurry, and then 30 g of sodium chloride is added and dissolved. Next, 1 N hydrochloric acid is added to adjust the pH of the slurry to about 3.0 to 3.5, and pure water is added until the slurry becomes 150 ml. This slurry is adjusted to pH 4.0 with 0.1 N sodium hydroxide at 25 ° C. using an automatic titration device (manufactured by Hiranuma Sangyo Co., Ltd., COM-1700), and the volume V [L] of the 0.1 N sodium hydroxide solution required to increase the pH from 4.0 to 9.0 by pH titration is measured. The silanol group density can be calculated by the formula below.

[0020]

number

[0021] In the above formula, ρ is the silanol group density (pcs / nm 2 ) ; c represents the concentration (mol / L) of the sodium hydroxide solution used in the titration; V is the volume (L) of sodium hydroxide solution required to raise the pH from 4.0 to 9.0 Represents; N A represents the Avogadro constant (units / mol); C represents the total mass (solids) of the abrasive grains (g); S is the weighted average value of the BET specific surface area of ​​the abrasive grains (nm 2 / g).

[0022] In one embodiment of the present invention, the average primary particle size of the abrasive grains is 5 nm or more, 10 nm or more, 12 nm or more, 14 nm or more, 16 nm or more, 18 nm or more, 20 nm or more, or 22 nm or more. In one embodiment of the polishing composition, the average primary particle size of the abrasive grains is 50 nm or less, 40 nm or less, 38 nm or less, 36 nm or less, less than 35 nm, 34 nm or less, 32 nm or less, 30 nm or less, 28 nm or less, 26 nm or less, or 24 nm or less. By being less than 35 nm, the desired effect of the present invention can be efficiently achieved. In one embodiment of the present invention, the method for measuring the average primary particle size of the abrasive grains may be the method described in the examples.

[0023] In one embodiment of the present invention, the average secondary particle size of the abrasive grains is 10 nm or more, 12 nm or more, 14 nm or more, 16 nm or more, 18 nm or more, 20 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, or 45 nm or more. In one embodiment of the polishing composition, the average primary particle size of the abrasive grains is 100 nm or less, 90 nm or less, 80 nm or less, 75 nm or less, 70 nm or less, 65 nm or less, 60 nm or less, or 55 nm or less. In one embodiment of the present invention, the method for measuring the average secondary particle size of the abrasive grains may be the method described in the Examples.

[0024] In one embodiment of the present invention, the lower limit of the average degree of association of the abrasive grains in the polishing composition (average secondary particle size / average primary particle size) is 1.3 or more, 1.4 or more, 1.5 or more, more than 1.5, 1.6 or more, 1.7 or more, 1.8 or more, more than 1.8, 1.9 or more, 2.0 or more, or 2.1 or more. In particular, the expected effect of the present invention is efficiently achieved by the average degree of association of the abrasive grains in the polishing composition (average secondary particle size / average primary particle size) being more than 1.5 or more than 1.8. In one embodiment of the present invention, the upper limit of the average degree of association of the abrasive grains in the polishing composition is 4.0 or less, 3.5 or less, 3.3 or less, 3.1 or less, 2.9 or less, 2.7 or less, or 2.5 or less.

[0025] In one embodiment of the present invention, the content of the abrasive grains in the polishing composition is 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 0.9% by mass or more, 1.1% by mass or more, 1.3% by mass or more, 1.5% by mass or more, or 1.7% by mass or more, 1.8% by mass or more, more than 1.8% by mass, 2.0% by mass or more, 2.2% by mass or more, or 2.4% by mass or more. In one embodiment of the present invention, the content of the abrasive grains in the polishing composition is 10% by mass or less, 8% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, less than 3% by mass, 2.8% by mass or less, 2.3% by mass or less, 2.1% by mass or less, or 1.9% by mass or less.

[0026] In one embodiment of the present invention, the zeta potential of the abrasive grains in the polishing composition is positive, specifically, more than 2mV, 4mV or more, 6mV or more, 8mV or more, 10mV or more, 12mV or more, 13mV or more, 14mV or more, 16mV or more, 18mV or more, 20mV or more, or 22mV or more. If the surface of the abrasive grains is not cation-modified, the zeta potential may be insufficient, and the desired effect of the present invention may not be achieved. In one embodiment of the present invention, the zeta potential of the abrasive grains in the polishing composition is 40mV or less, 38mV or less, 36mV or less, 34mV or less, 32mV or less, less than 32mV, 30mV or less, 28mV or less, 26mV or less, 24mV or less, 22mV or less, 20mV or less, 18mV or less, 16mV or less, or 14mV or less. In particular, when it is less than 32 mV, the desired effect of the present invention is efficiently achieved.

[0027] [Polishing speed enhancer for silicon-containing objects] In one embodiment of the present invention, the polishing composition contains an agent for enhancing the polishing rate of a silicon-containing object to be polished, and the agent for enhancing the polishing rate of a silicon-containing object to be polished contains an α-keto acid. Thus, the present invention provides an agent for enhancing the polishing rate of a silicon-containing object to be polished, which contains an α-keto acid. In one embodiment of the present invention, the α-keto acid is one of the following:

[0028] [ka]

[0029] It is represented by the general formula: 1 is an alkyl group, a carboxylalkyl group or an alkoxycarbonylalkyl group.

[0030] In one embodiment of the present invention, the number of carbon atoms in the alkyl group is 1 to 5, 1 to 4, 1 to 3, or 1 or 2. Of these, from the viewpoint of efficiently achieving the intended effects of the present invention, the number of carbon atoms in the alkyl group is preferably 1 or 2. In one embodiment of the present invention, the alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an n-pentyl group, or the like. Of these, from the viewpoint of efficiently achieving the intended effects of the present invention, the alkyl group is preferably a methyl group or an ethyl group.

[0031] In one embodiment of the present invention, the number of carbon atoms in the alkyl group in the carboxylalkyl group is 1 to 5, 1 to 4, 1 to 3, or 1 or 2. In particular, from the viewpoint of efficiently achieving the intended effects of the present invention, the number of carbon atoms in the alkyl group in the carboxylalkyl group is preferably 1 or 2 or more, and more preferably 2 or more. In one embodiment of the present invention, the carboxylalkyl group is preferably a carboxylmethyl group, a carboxylethyl group, a carboxylpropyl group, a carboxylbutyl group, a carboxylpentyl group, or the like. In particular, from the viewpoint of efficiently achieving the intended effects of the present invention, a carboxylmethyl group or a carboxylethyl group is preferable, and a carboxylethyl group is more preferable.

[0032] In one embodiment of the present invention, the number of carbon atoms in the alkyl group in the alkoxycarbonylalkyl group is 1 to 5, 1 to 4, 1 to 3, or 1 or 2. In one embodiment of the present invention, the number of carbon atoms in the alkoxy group in the alkoxycarbonylalkyl group is 1 to 5, 1 to 4, 1 to 3, or 1 or 2. In one embodiment of the present invention, preferred examples of the alkoxycarbonylalkyl group include a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group, a propoxycarbonylethyl group, an isopropoxycarbonylethyl group, a butoxycarbonylmethyl group, an isobutoxycarbonylethyl group, a tertiary butoxycarbonylmethyl group, a pentyloxycarbonylmethyl group, and the like.

[0033] In one embodiment of the present invention, the alpha keto acid is at least one selected from the group consisting of pyruvic acid, 2-oxoglutaric acid, and oxaloacetic acid.

[0034] In one embodiment of the present invention, the content of the polishing rate enhancer for the polishing object containing silicon atoms in the polishing composition is 0.01 mM or more, 0.05 mM or more, 0.1 mM or more, 0.5 mM or more, 1 mM or more, 2 mM or more, 4 mM or more, 5 mM or more, more than 5 mM, 5.5 mM or more, 6 mM or more, 8 mM or more, 10 mM or more, 10.5 mM or more, 12 mM or more, 14 mM or more, 16 mM or more, or 18 mM or more. In particular, the content of the polishing rate enhancer for the polishing object containing silicon atoms in the polishing composition is more than 5 mM, thereby efficiently achieving the desired effect of the present invention. In one embodiment of the present invention, the content of the polishing rate enhancer for the polishing object containing silicon atoms in the polishing composition is 200mM or less, 150mM or less, 100mM or less, 80mM or less, 60mM or less, 40mM or less, 30mM or less, 25mM or less, 20mM or less, less than 20mM, 19.5mM or less, 18mM or less, 16mM or less, 14mM or less, 12mM or less, 10mM or less, 9.5mM or less, 8mM or less, or 7mM or less. In particular, the content of the polishing rate enhancer for the polishing object containing silicon atoms in the polishing composition is less than 20mM, thereby efficiently achieving the desired effect of the present invention.

[0035] The polishing rate enhancer for a silicon-containing object to be polished in the present invention can also contribute to improving the polishing rate for a titanium-containing object to be polished. In this sense, the present invention provides a polishing rate enhancer that contains an α-keto acid and enhances the polishing rate for at least one of a silicon-containing object to be polished and a titanium-containing object to be polished.

[0036] [Oxidizing agent] In one embodiment of the present invention, the polishing composition may contain an oxidizing agent.

[0037] In one embodiment of the present invention, the oxidizing agent is preferably a peroxide. Specific examples of such peroxides include, but are not limited to, hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, and potassium monopersulfate. The above oxidizing agents may be used alone or in combination of two or more.

[0038] In one embodiment of the present invention, the lower limit of the content (active ingredient concentration) of the oxidizing agent in the polishing composition (the total when two or more types are used) is 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, or 0.05 mass% or more. In one embodiment of the present invention, the upper limit of the content (active ingredient concentration) of the oxidizing agent in the polishing composition (the total when two or more types are used) is 10 mass% or less, 5 mass% or less, 3 mass% or less, 2 mass% or less, or 1 mass% or less.

[0039] [Liquid carrier] In one embodiment of the present invention, the polishing composition includes a liquid carrier. The liquid carrier has a function of dispersing or dissolving each component. In one embodiment of the present invention, when the liquid carrier includes an organic solvent, the content of the organic solvent is less than 7% by mass, 6% by mass or less, 4% by mass or less, 2% by mass or less, or 1% by mass or less. The organic solvent may be, for example, at least one selected from the group consisting of monoalcohols, dialcohols, and cellosolves. In one embodiment of the present invention, the liquid carrier is only water. In one embodiment of the present invention, the water is preferably water that contains as few impurities as possible from the viewpoint of preventing contamination of the polishing object and the action of other components. Here, the purity of the water can be increased by, for example, removing impurity ions using an ion exchange resin, removing foreign matter with a filter, distillation, or other operations. Specifically, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc. as the water.

[0040] [pH of polishing composition] In one embodiment of the present invention, the pH of the polishing composition is more than 2.5, 2.6 or more, 2.7 or more, 2.8 or more, 2.9 or more, 3.0 or more, 3.2 or more, 3.5 or more, 3.8 or more, 4.0 or more, 4.5 or more, 5.0 or more, 5.5 or more, or 5.8 or more. If the pH of the polishing composition is 2.5 or less, the expected effect of the present invention may not be achieved. In one embodiment of the present invention, the pH of the polishing composition is 11 or less, 9 or less, 7 or less, less than 7, 6.8 or less, 6.6 or less, 6.4 or less, 6.2 or less, 6 or less, less than 6, 5.8 or less, 5.6 or less, 5.4 or less, 5.2 or less, 5 or less, 4.8 or less, 4.6 or less, 4.4 or less, 4.2 or less, 4 or less, less than 4, 3.8 or less, 3.6 or less, 3.4 or less, or 3.2 or less. In this specification, the pH of the polishing composition can be measured according to the method described in the Examples.

[0041] In one embodiment of the present invention, the polishing composition contains a pH adjuster. As the pH adjuster, an acid, a base, or a salt thereof can be used.

[0042] In one embodiment of the present invention, the acid may be an inorganic acid such as periodic acid, hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, or phosphoric acid, or an organic acid such as citric acid, lactic acid, diglycolic acid, furancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, or phenoxyacetic acid.

[0043] In one embodiment of the present invention, examples of the base include amines such as aliphatic amines and aromatic amines, ammonium solutions, organic bases such as quaternary ammonium hydroxides, hydroxides of alkali metals such as potassium hydroxide, hydroxides of Group 2 elements, amino acids such as histidine, ammonia, and the like.

[0044] According to one embodiment of the present invention, in the polishing composition, the content of the pH adjuster can be appropriately adjusted to obtain a desired pH.

[0045] [Polished object] In one embodiment of the present invention, the object to be polished contains silicon atoms. Examples of objects to be polished that contain silicon atoms include single crystal silicon, polycrystalline silicon, silicon oxide, silicon nitride, and the like. In one embodiment of the present invention, the object to be polished that contains silicon atoms is doped with at least one trivalent element (e.g., boron, gallium, indium, and the like). In one embodiment of the present invention, the object to be polished contains titanium atoms. Examples of objects to be polished that contain titanium atoms include titanium nitride, titanium, titanium alloys, and the like.

[0046] In the present invention, the polishing composition contains an α-keto acid, thereby improving the polishing rate of an object to be polished that contains silicon atoms. In one embodiment of the present invention, the polishing composition contains an α-keto acid, thereby improving the polishing rate of an object to be polished that contains titanium atoms. Thus, in the present invention, there is provided an agent for improving the polishing rate of an object to be polished that contains a silicon atom, which agent contains an α-keto acid. In addition, in the present invention, there is provided an agent for improving the polishing rate of an object to be polished that contains a titanium atom, which agent contains an α-keto acid.

[0047] [Other additives] In one embodiment of the present invention, the polishing composition may or may not contain other additives.Specific examples of other additives include complexing agents, metal anticorrosives, preservatives, antifungal agents, reducing agents, water-soluble polymers, organic solvents for dissolving poorly soluble organic matter, etc.The term "not containing" used in this specification also includes the case where the corresponding component is not contained at all in the polishing composition, and the case where the corresponding component is contained in an amount of 0.5 mass ppm or less.

[0048] Among the other additives, the complexing agent, metal corrosion inhibitor, preservative, and fungicide will be described below.

[0049] (Complexing Agent) The complexing agent has the effect of chemically etching the surface of the object to be polished, and can more effectively increase the polishing rate of the object to be polished with the polishing composition.

[0050] Examples of the complexing agent include inorganic acids or salts thereof, organic acids or salts thereof, nitrile compounds, amino acids, and chelating agents. These complexing agents may be used alone or in combination of two or more. The complexing agent may be a commercially available product or a synthetic product.

[0051] The complexing agent may be a salt of the inorganic acid or the organic acid. In particular, when a salt of a weak acid and a strong base, a salt of a strong acid and a weak base, or a salt of a weak acid and a weak base is used, a pH buffering effect can be expected.

[0052] Examples of such salts include potassium chloride, sodium sulfate, potassium nitrate, potassium carbonate, potassium tetrafluoroborate, potassium pyrophosphate, potassium oxalate, trisodium citrate, (+)-potassium tartrate, potassium hexafluorophosphate, and the like.

[0053] Specific examples of the nitrile compound include acetonitrile, aminoacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile, glutarodinitrile, and methoxyacetonitrile.

[0054] Specific examples of amino acids include glycine, α-alanine, β-alanine, N-methylglycine, N,N-dimethylglycine, 2-aminobutyric acid, norvaline, valine, leucine, norleucine, isoleucine, phenylalanine, proline, sarcosine, ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, bicine, tricine, 3,5-diiodo-tyrosine, β-(3,4-dihydroxyphenyl)-alanine, thyroxine, These include 4-hydroxy-proline, cysteine, methionine, ethionine, lanthionine, cystathionine, cystine, cysteic acid, aspartic acid, glutamic acid, S-(carboxymethyl)-cysteine, 4-aminobutyric acid, asparagine, glutamine, azaserine, arginine, canavanine, citrulline, delta-hydroxy-lysine, creatine, histidine, 1-methyl-histidine, 3-methyl-histidine and tryptophan.

[0055] Specific examples of the chelating agent include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N,N,N-trimethylenephosphonic acid, ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid, transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol ether diaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), N-(2-carboxylate ethyl)-L-aspartic acid, β-alanine diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid, and 1,2-dihydroxybenzene-4,6-disulfonic acid.

[0056] When the polishing composition contains a complexing agent, the content (active ingredient concentration) of the complexing agent is not particularly limited. For example, the lower limit of the content (active ingredient concentration) of the complexing agent is not particularly limited because it is effective even in a small amount, but is preferably 0.001 g / L or more, more preferably 0.01 g / L or more, and even more preferably 1 g / L or more. In addition, the upper limit of the content (active ingredient concentration) of the complexing agent is preferably 20 g / L or less, more preferably 15 g / L or less, and even more preferably 10 g / L or less. If it is in such a range, the polishing speed of the object to be polished is improved, and it is advantageous in improving the smoothness of the surface of the object to be polished after polishing with the polishing composition.

[0057] (Metal corrosion inhibitor) Metal corrosion inhibitors act to prevent the dissolution of metals, thereby suppressing deterioration of the surface condition, such as roughening of the polished surface.

[0058] The metal corrosion inhibitor is a heterocyclic compound or a surfactant. The number of members of the heterocyclic ring in the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having a condensed ring. The metal corrosion inhibitor may be used alone or in combination of two or more kinds. The metal corrosion inhibitor may be a commercially available product or a synthetic product.

[0059] Specific examples of the heterocyclic compound include nitrogen-containing heterocyclic compounds such as pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyrindine compounds, indolizine compounds, indole compounds, isoindole compounds, indazole compounds, purine compounds, quinolizine compounds, quinoline compounds, isoquinoline compounds, naphthyridine compounds, phthalazine compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, buteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, and furazan compounds.

[0060] More specifically, examples of pyrazole compounds include 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, 3-amino-5-phenylpyrazole, 5-amino-3-phenylpyrazole, 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3-methylpyrazole, 1-methylpyrazole, 3-amino-5-methylpyrazole, 4-amino-pyrazolo[3,4-d]pyrimidine, allopurinol, 4-chloro-1H-pyrazolo[3,4-D]pyrimidine, 3,4-dihydroxy-6-methylpyrazolo(3,4-B)-pyridine, and 6-methyl-1H-pyrazolo[3,4-b]pyridin-3-amine.

[0061] Examples of the imidazole compound include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylpyrazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2-(1-hydroxyethyl)benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2,5-dimethylbenzimidazole, 5-methylbenzimidazole, and 5-nitrobenzimidazole.

[0062] Examples of triazole compounds include, for example, 1,2,3-triazole (1H-BTA), 1,2,4-triazole, 1-methyl-1,2,4-triazole, methyl-1H-1,2,4-triazole-3-carboxylate, 1,2,4-triazole-3-carboxylic acid, methyl 1,2,4-triazole-3-carboxylate, 1H-1,2,4-triazole-3-thiol, 3,5-diamino-1H-1,2,4-triazole, 3-amino-1,2,4 -triazole-5-thiol, 3-amino-1H-1,2,4-triazole, 3-amino-5-benzyl-4H-1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4-triazole, 3-nitro-1,2,4-triazole, 3-bromo-5-nitro-1,2,4-triazole, 4-(1,2,4-triazol-1-yl)phenol, 4-amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1,2,4 -triazole, 4-amino-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl-1,2,4-triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1-(1',2'-dicarboxyethyl)benzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]benzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-5-methylbenzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-4-methylbenzotriazole, and the like.

[0063] Examples of the tetrazole compound include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, and 5-phenyltetrazole.

[0064] Examples of indazole compounds include 1H-indazole, 5-amino-1H-indazole, 5-nitro-1H-indazole, 5-hydroxy-1H-indazole, 6-amino-1H-indazole, 6-nitro-1H-indazole, 6-hydroxy-1H-indazole, and 3-carboxy-5-methyl-1H-indazole.

[0065] Examples of indole compounds include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, 5-methyl-1H-indole, 6-methyl-1H-indole, 7-methyl-1H-indole, 4-amino-1H-indole, 5-amino-1H-indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydro-1H-indole, 5-amino-1H-indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydro-1H-indole, 5-amino-1H-indole, 6-hydro ... 1H-indole, 5-hydroxy-1H-indole, 6-hydroxy-1H-indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6-methoxy-1H-indole, 7-methoxy-1H-indole, 4-chloro-1H-indole, 5-chloro-1H-indole, 6-chloro-1H-indole, 7-chloro-1H-indole, 4-carboxy-1H- Indole, 5-carboxy-1H-indole, 6-carboxy-1H-indole, 7-carboxy-1H-indole, 4-nitro-1H-indole, 5-nitro-1H-indole, 6-nitro-1H-indole, 7-nitro-1H-indole, 4-nitrile-1H-indole, 5-nitrile-1H-indole, 6-nitrile-1H-indole, 7-nitrile-1H-indole, 2,5-dimethyl-1H-indole Indole, 1,2-dimethyl-1H-indole, 1,3-dimethyl-1H-indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H-indole, 7-ethyl-1H-indole, 5-(aminomethyl)indole, 2-methyl-5-amino-1H-indole, 3-hydroxymethyl-1H-indole, 6-isopropyl-1H-indole, 5-chloro-2-methyl-1H-indole, and the like.

[0066] Moreover, examples of surfactants used as metal corrosion inhibitors include anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0067] Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyl ether sulfates, alkyl benzene sulfonates, alkyl phosphates, polyoxyethylene alkyl phosphates, polyoxyethylene sulfosuccinic acids, alkyl sulfosuccinic acids, alkyl naphthalene sulfonates, alkyl diphenyl ether disulfonic acids, and salts thereof.

[0068] Examples of the cationic surfactant include alkyldimethylammonium salts, alkylbenzyldimethylammonium salts, and alkylamine salts.

[0069] Examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.

[0070] Specific examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, and alkyl alkanolamides.

[0071] When the polishing composition contains a metal corrosion inhibitor, the content (active ingredient concentration) of the metal corrosion inhibitor is not particularly limited.For example, the lower limit of the content (active ingredient concentration) of the metal corrosion inhibitor is preferably 0.001g / L or more, more preferably 0.005g / L or more, and even more preferably 0.01g / L or more.In addition, the upper limit of the content (active ingredient concentration) of the metal corrosion inhibitor is preferably 10g / L or less, more preferably 5g / L or less, and even more preferably 2g / L or less.Within such a range, it is possible to prevent the dissolution of metal and suppress the deterioration of the surface condition such as the surface roughness of the polished surface.

[0072] (Preservatives and fungicides) Furthermore, examples of preservatives and antifungal agents that may be contained in the polishing composition if necessary include isothiazoline preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, paraoxybenzoic acid esters, and phenoxyethanol, etc. These preservatives and antifungal agents may be used alone or in combination of two or more kinds.

[0073] [Electrical conductivity (EC) of polishing composition] According to one embodiment of the present invention, the lower limit of the electrical conductivity (EC) of the polishing composition is 0.01 mS / cm or more, 0.1 mS / cm or more, 0.2 mS / cm or more, 0.3 mS / cm or more, 0.4 mS / cm or more, 0.5 mS / cm or more, 0.6 mS / cm or more, 0.8 mS / cm or more, or 1.0 mS / cm or more. According to one embodiment of the present invention, the upper limit of the electrical conductivity (EC) of the polishing composition is 10 mS / cm or less, 5 mS / cm or less, 3 mS / cm or less, 2 mS / cm or less, 1.8 mS / cm or less, 1.5 mS / cm or less, 1.2 mS / cm or less, 1 mS / cm or less, 0.8 mS / cm or less, or 0.6 mS / cm or less. The electrical conductivity of the polishing composition can be adjusted by appropriately changing the content of a pH adjuster, a polishing rate enhancer, etc. The electrical conductivity of the polishing composition is a value measured by a tabletop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71).

[0074] [Particularly preferred combinations of embodiments of the polishing composition] As described above, it must be understood that all combinations of the embodiments are disclosed in the present application, but particularly preferred combinations of the embodiments of the polishing composition will be described below.

[0075] That is, according to one embodiment of the present invention, the content of the abrasive grains is more than 1.8 mass %. In the polishing composition of one embodiment of the present invention, the average primary particle size of the abrasive grains is less than 35 nm, and the number of silanol groups per unit surface area of ​​the abrasive grains (silanol group density) is 5.7 / nm 2 According to one embodiment of the present invention, the polishing composition satisfies at least one of the following conditions: pH is greater than 2.5; In one embodiment of the present invention, the content of the polishing rate enhancer for a polishing object containing silicon atoms in the polishing composition is greater than 5 mM; In one embodiment of the present invention, the content of the polishing rate enhancer for a polishing object containing silicon atoms in the polishing composition is less than 20 mM.

[0076] <Method of manufacturing the polishing composition> According to one embodiment of the present invention, the method for producing the polishing composition is not particularly limited. The method for producing the polishing composition includes, for example, mixing an abrasive grain, a polishing rate enhancer for an object to be polished that contains silicon atoms, and a liquid carrier, and the abrasive grain has a cation-modified surface, and the polishing rate enhancer contains an alpha-keto acid. The temperature at which each component is mixed is not particularly limited, but is preferably 10 to 40°C, and may be heated to increase the dissolution rate. The mixing time is also not particularly limited.

[0077] <Polishing method and substrate manufacturing method> The present invention provides a method for polishing an object to be polished, which comprises polishing the object to be polished using the above-mentioned polishing composition.The present invention also provides a method for manufacturing a substrate, which comprises polishing a substrate before polishing using the above-mentioned polishing method.In one embodiment of the present invention, the substrate is preferably one of the objects listed in the above [object to be polished].

[0078] In one embodiment of the present invention, the polishing method can be carried out using a polishing apparatus.

[0079] As a polishing device, a general polishing device can be used that is equipped with a holder for holding a substrate or the like having an object to be polished, a motor whose rotation speed can be changed, and a polishing platen onto which a polishing pad (polishing cloth) can be attached.

[0080] The polishing pad may be made of any material, including, without particular limitation, a general nonwoven fabric, polyurethane, porous fluororesin, etc. The polishing pad is preferably provided with grooves for storing the polishing liquid.

[0081] The polishing conditions are not particularly limited. For example, the rotation speed of the polishing platen is preferably 10 to 500 rpm, and the pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 0.5 to 10 psi.

[0082] The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the composition using a pump, etc. is adopted. There is no limit to the amount of the composition supplied, but it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.

[0083] After polishing, the substrate is washed with running water, and water droplets adhering to the substrate are removed by a spin dryer or the like, followed by drying to obtain the substrate. EXAMPLES

[0084] 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 "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were performed under the conditions of room temperature (25°C) / relative humidity 40-50%RH.

[0085] <Preparation of Polishing Composition> The polishing composition was prepared by stirring and mixing in water (mixing temperature: about 25°C, mixing time: about 10 minutes) the abrasive grains having amino groups fixed on the surface, the polishing rate enhancer (the comparative example is a similar substance), the pH adjuster, and 3.0 g / kg of an oxidizing agent (31% H2O2) of the composition shown in Table 1. Note that "-" in Table 1 means that the component was not added.

[0086] <Average primary particle size of abrasive grains> The average primary particle size of the abrasive grains was calculated from the specific surface area of ​​the abrasive grains measured by the BET method using "Flow SorbII 2300" manufactured by Micromeritics, and the density of the abrasive grains.

[0087] <Average secondary particle size of abrasive grains> The average secondary particle size of the abrasive grains was calculated by dynamic light scattering method measured using "UPA-UT151" manufactured by Microtrac.

[0088] <pH of polishing composition> The pH of the polishing composition was determined using a glass electrode type hydrogen ion concentration indicator (Model No. F-23, manufactured by Horiba, Ltd.) by performing three-point calibration using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C), neutral phosphate pH buffer solution, pH: 6.86 (25°C), carbonate pH buffer solution, pH: 10.01 (25°C)), after which the glass electrode was placed in the polishing composition and the value was measured after stabilization for at least 2 minutes.

[0089] <Zeta potential of abrasive grains> The polishing composition was provided to ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., and measurement was carried out by the laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25° C. The obtained data was analyzed by the Smoluchowski formula to calculate the zeta potential of the abrasive grains in the polishing composition.

[0090] <Polishing speed> The object to be polished is 200mm wafer (TEOS (silicon oxide film)), 200mm wafer (SiN (silicon nitride) film), 200mm wafer (TiN (titanium nitride) film), was prepared.

[0091] Polishing was performed under the following polishing conditions using the polishing composition, and the polishing rate of TEOS was determined by measuring the thickness (film thickness) of the polished object before and after polishing using a manual sheet resistance meter (VR-120, manufactured by Hitachi Kokusai Electric Inc.) and dividing the difference in the thickness (film thickness) of the polished object before and after polishing by the polishing time (min). The polishing rate of TiN film was determined by dividing the difference in the thickness (Å) of TiN blanket wafer before and after polishing measured using a sheet resistance meter based on the principle of the DC 4-probe method by the polishing time (min). The polishing rate of SiN film was determined by dividing the difference in the thickness (Å) of SiN blanket wafer before and after polishing measured using an optical interference film thickness meter (manufactured by Filmetrics Inc.: model number Filmetrics F50) by the polishing time (min).

[0092] (polishing conditions) Polishing machine: Single-sided CMP polishing machine (ENGIS) Polishing pad: Polyurethane pad (IC1010: manufactured by Rohm and Haas) Pressure: 3.4psi Platen rotation speed: 100 rpm Head (carrier) rotation speed: 100 rpm Flow rate of polishing composition: 100ml / min Dress: Diamond Disk (in-situ condition).

[0093] [Table 1-1]

[0094] [Table 1-2]

Claims

1. Abrasive grains and an agent for increasing the polishing speed of an object to be polished, the agent including silicon atoms; A liquid carrier; Including, the abrasive grains have surfaces that are cationically modified; A polishing composition for polishing an object containing silicon atoms, wherein the polishing rate enhancer comprises an α-keto acid.

2. The polishing composition of claim 1 , having a pH greater than 2.

5.

3. The polishing composition according to claim 1 or 2, for polishing an object to be polished which further contains titanium atoms.

4. The number of silanol groups per unit surface area of ​​the abrasive grain is 2.0 / nm ２ The polishing composition according to any one of claims 1 to 3, wherein the polishing composition has a viscosity of 1000:1 or more.

5. 5. The polishing composition according to claim 1, wherein when the liquid carrier contains an organic solvent, the content of the organic solvent is less than 7 mass %.

6. 6. The polishing composition according to claim 1, wherein the degree of association of the abrasive grains is more than 1.

8.

7. 7. The polishing composition according to claim 1, wherein the abrasive grains have a positive zeta potential.

8. The polishing composition according to any one of claims 1 to 7, wherein the abrasive grains are abrasive grains other than ceria.

9. The polishing composition according to claim 8 , wherein the abrasive is silica.

10. The alpha keto acid is selected from the group consisting of: 【Chemistry 1】 and R １ The polishing composition according to any one of claims 1 to 9, wherein is an alkyl group, a carboxylalkyl group, or an alkoxycarbonylalkyl group.

11. 11. The polishing composition according to claim 10, wherein the α-keto acid is at least one selected from the group consisting of pyruvic acid, 2-oxoglutaric acid, and oxalacetic acid.

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