Polishing composition for silicon substrates

Abstract

To provide a polishing liquid composition that can reduce the surface roughness (haze) of a silicon substrate.SOLUTION: A polishing liquid composition for a silicon substrate contains the following component A, component B, and component C. The component A includes silica particles, the component B includes a nitrogen-containing basic compound, and the component C includes a cationic surfactant of at least one of a quaternary ammonium having two or more alkyl groups each having 10 to 18 carbon atoms in the molecule or a salt thereof (component C1), and a quaternary phosphonium having one or more alkyl groups each having 10 to 18 carbon atoms in the molecule or a salt thereof (component C2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a polishing composition for silicon substrates, a polishing method using the same, and a method for manufacturing a semiconductor substrate. [Background technology]

[0002] In recent years, the increasing demand for higher storage capacity in semiconductor memories has led to the miniaturization of semiconductor device design rules. As a result, the depth of focus in photolithography used in the semiconductor device manufacturing process has become shallower, and the demand for reduced surface roughness (haze) on silicon substrates (bare wafers) has become increasingly stringent.

[0003] To improve the quality of silicon substrates, polishing of silicon substrates is performed in multiple stages. In particular, the final polishing stage, finish polishing, is performed to reduce haze.

[0004] For example, Patent Document 1 proposes a semiconductor polishing composition containing abrasive grains, a basic low-molecular-weight compound, and a water-soluble polymer compound, the basic low-molecular-weight compound containing a quaternary ammonium compound, and the content of the quaternary ammonium compound is 0.5 ppm to 100 ppm of the total amount of the semiconductor polishing composition. An example of this document describes a semiconductor polishing composition containing 0.1 wt % colloidal silica, 250 ppm ammonia, 5 ppm or 15 ppm tetramethylammonium hydroxide (TMAH), and 120 ppm hydroxyethyl cellulose (HEC). Patent Document 2 proposes a semiconductor polishing composition containing abrasive grains and a quaternary ammonium salt having one alkyl chain with six or more carbon atoms. The examples in this document describe a semiconductor polishing composition containing 1.0 wt % colloidal silica, 0.1 wt % tetramethylammonium hydroxide (TMAH), and 0.005 wt % hexadecyltrimethylammonium chloride. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-352043 [Patent Document 2] Japanese Patent Application Publication No. 2020-203980 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, requirements for the surface quality of silicon substrates such as silicon wafers have become increasingly stringent, and there is a demand for polishing compositions that can reduce the surface roughness (haze) of silicon substrates. Patent Document 2 describes that surface roughness (haze) can be reduced by using hexadecyltrimethylammonium chloride, a quaternary ammonium salt having one long alkyl chain, but in recent years, there has been a demand for even greater reductions in surface roughness (haze).

[0007] Therefore, the present disclosure provides a polishing composition for silicon substrates that can reduce the surface roughness (haze) of silicon substrates, as well as a polishing method and a method for manufacturing semiconductor substrates using the same. [Means for solving the problem]

[0008] In one aspect, the present disclosure relates to a polishing liquid composition for silicon substrates, comprising the following component A, component B, and component C: Component A: Silica particles Component B: Nitrogen-containing basic compound Component C: At least one cationic surfactant selected from the group consisting of a quaternary ammonium or salt thereof having two or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C1), and a quaternary phosphonium or salt thereof having one or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C2).

[0009] In one aspect, the present disclosure relates to a method for polishing a silicon substrate, comprising a step of polishing a silicon substrate to be polished using the polishing liquid composition of the present disclosure.

[0010] In one aspect, the present disclosure relates to a method for producing a semiconductor substrate, comprising the steps of polishing a silicon substrate to be polished with the polishing liquid composition of the present disclosure and cleaning the polished silicon substrate. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a polishing composition that can reduce the surface roughness (haze) of a silicon substrate, a polishing method that uses the polishing composition, and a method for manufacturing a semiconductor substrate. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure is based on the finding that surface roughness (haze) can be reduced by adding a specific cationic surfactant to a polishing composition containing silica particles and a nitrogen-containing basic compound.

[0013] That is, in one aspect, the present disclosure relates to a polishing liquid composition for silicon substrates (hereinafter also referred to as "the polishing liquid composition of the present disclosure") containing the following component A, component B, and component C: Component A: Silica particles Component B: Nitrogen-containing basic compound Component C: At least one cationic surfactant selected from the group consisting of a quaternary ammonium or salt thereof having two or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C1), and a quaternary phosphonium or salt thereof having one or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C2).

[0014] According to one or more embodiments of the present disclosure, the surface roughness (haze) of a silicon substrate can be reduced.

[0015] Although the details of the mechanism by which the effects of the present disclosure are exerted are not clear, it is presumed as follows. Single-crystal silicon substrates are dissolved by hydroxy ions, but there are dissolved and insoluble areas, and it is presumed that the surface cannot be dissolved uniformly, resulting in a worsening of surface roughness (haze). The chemical structure of the insoluble areas is unknown, but since the dissolution reaction does not proceed with highly hydrophilic hydroxy ions, it is presumed to have hydrophobic properties. In the present disclosure, a highly hydrophobic cationic surfactant is used, which is at least one of a quaternary ammonium or its salt having two or more long alkyl chains (component C1) and a quaternary phosphonium or its salt having one or more long alkyl chains (component C2). The hydrophobic long alkyl chains are adsorbed to the hydrophobic insoluble portion on the silicon substrate, and the cationic portion (N + , P + It is thought that the dissolution proceeds because the negatively charged hydroxy ions of the dissolving agent are attracted by the cationic surfactant, or the dissolution proceeds because of the cationic surfactant. As a result, the difference in the amount of dissolution between the dissolved and undissolved parts becomes smaller, which is thought to reduce surface roughness (haze). However, the present disclosure need not be construed as being limited to these mechanisms.

[0016] [Silica particles (component A)] The polishing composition of the present disclosure contains silica particles (hereinafter also referred to as "Component A") as an abrasive. Examples of Component A include colloidal silica, fumed silica, pulverized silica, and surface-modified silica thereof, with colloidal silica being preferred from the viewpoint of reducing surface roughness (haze). Component A may be one type or a combination of two or more types.

[0017] From the viewpoint of ease of use, the use form of Component A is preferably a slurry. When Component A contained in the polishing liquid composition of the present disclosure is colloidal silica, from the viewpoint of preventing contamination of silicon substrates with alkali metals, alkaline earth metals, etc., the colloidal silica is preferably obtained from a hydrolyzate of an alkoxysilane. Silica particles obtained from a hydrolyzate of an alkoxysilane can be produced by a conventionally known method.

[0018] From the viewpoint of reducing surface roughness (haze), the average primary particle diameter of component A is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, even more preferably 25 nm or more, and is preferably 40 nm or less, more preferably 35 nm or less. From the same viewpoint, the average primary particle diameter of component A is preferably 10 nm or more and 40 nm or less, more preferably 15 nm or more and 35 nm or less, even more preferably 20 nm or more and 35 nm or less, even more preferably 25 nm or more and 35 nm or less.

[0019] In the present disclosure, the average primary particle size of component A is determined by the specific surface area S (m 2 The specific surface area can be measured, for example, by the method described in the Examples.

[0020] From the viewpoint of reducing surface roughness (haze), the average secondary particle diameter of component A is preferably 20 nm or more, more preferably 30 nm or more, even more preferably 40 nm or more, and is preferably 80 nm or less, more preferably 75 nm or less, and even more preferably 70 nm or less. From the same viewpoint, the average secondary particle diameter of component A is preferably 20 nm or more and 80 nm or less, more preferably 30 nm or more and 75 nm or less, and even more preferably 40 nm or more and 70 nm or less. In the present disclosure, the average secondary particle diameter is a value measured by dynamic light scattering (DLS) and can be measured, for example, using the device described in the examples.

[0021] From the viewpoint of reducing surface roughness (haze), the degree of association of component A is preferably 3 or less, more preferably 2.5 or less, even more preferably 2.3 or less, and is preferably 1.1 or more, more preferably 1.5 or more, even more preferably 1.8 or more.

[0022] In the present disclosure, the degree of association of component A is a coefficient representing the shape of silica particles and is calculated by the following formula. Degree of association = average secondary particle size / average primary particle size

[0023] The degree of association of component A can be adjusted by using methods described in, for example, JP-A Nos. 6-254383, 11-214338, 11-60232, 2005-060217, and 2005-060219.

[0024] The shape of component A is preferably a so-called sphere and / or a so-called cocoon shape.

[0025] From the viewpoint of reducing surface roughness (haze), the content of component A in the polishing liquid composition of the present disclosure is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.07 mass% or more, and preferably 2.5 mass% or less, more preferably 1 mass% or less, even more preferably 0.5 mass% or less, and even more preferably 0.2 mass% or less, calculated as SiO2. From the same viewpoint, the content of component A in the polishing liquid composition of the present disclosure is preferably 0.01 mass% or more and 2.5 mass% or less, more preferably 0.05 mass% or more and 1 mass% or less, more preferably 0.07 mass% or more and 0.5 mass% or less, even more preferably 0.07 mass% or more and 0.2 mass% or less, calculated as SiO2. When component A is a combination of two or more types, the content of component A refers to the total content thereof.

[0026] [Nitrogen-containing basic compound (component B)] The polishing composition of the present disclosure contains a nitrogen-containing basic compound (hereinafter also referred to as "component B"). Component B is preferably a water-soluble nitrogen-containing basic compound from the viewpoints of improving the polishing rate and reducing surface roughness (haze). In the present disclosure, "water-soluble" refers to a solubility in water (20°C) of 0.5 g / 100 mL or more, preferably 2 g / 100 mL or more. In the present disclosure, "water-soluble nitrogen-containing basic" refers to a nitrogen-containing compound that exhibits basicity when dissolved in water. Component B may be one type or a combination of two or more types.

[0027] In one or more embodiments, Component B may be at least one selected from an amine compound and an ammonium compound. Examples of Component B include one or a combination of two or more selected from ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, dimethylamine, trimethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyl-N,N-diethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-(β-aminoethyl)ethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine, hexamethylenediamine, piperazine hexahydrate, anhydrous piperazine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, diethylenetriamine, tetramethylammonium hydroxide, and hydroxyamine. Among these, from the viewpoint of improving the polishing rate and reducing the surface roughness (haze), ammonia or a mixture of ammonia and hydroxyamine is preferred as component B, and ammonia is more preferred.

[0028] From the viewpoints of improving the removal rate and reducing surface roughness (haze), the content of component B in the polishing composition of the present disclosure is preferably 5 ppm or more, more preferably 10 ppm or more, and even more preferably 20 ppm or more, and is preferably 500 ppm or less, more preferably 300 ppm or less, even more preferably 100 ppm or less, and even more preferably 60 ppm or less. From the same viewpoint, the content of component B in the polishing composition of the present disclosure is preferably 5 ppm or more and 500 ppm or less, more preferably 10 ppm or more and 300 ppm or less, more preferably 20 ppm or more and 100 ppm or less, and even more preferably 20 ppm or more and 50 ppm or less. When component B is a combination of two or more types, the content of component B refers to the total content thereof. In this disclosure, 10,000 ppm is 1 mass% (the same applies hereinafter).

[0029] From the viewpoints of improving the removal rate and reducing surface roughness (haze), the ratio B / A of the content of component B to the content of component A (mass ratio B / A) in the polishing liquid composition of the present disclosure is preferably 0.002 or more, more preferably 0.01 or more, even more preferably 0.025 or more, and preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less. From the same viewpoint, the mass ratio B / A in the polishing liquid composition of the present disclosure is preferably 0.002 or more and 1 or less, more preferably 0.01 or more and 0.5 or less, and even more preferably 0.025 or more and 0.1 or less.

[0030] [Cationic surfactant (ingredient C)] The polishing liquid composition of the present disclosure contains a cationic surfactant (hereinafter also referred to as "component C"). Component C is at least one of a quaternary ammonium having two or more alkyl groups having from 10 to 18 carbon atoms in the molecule or a salt thereof (hereinafter also referred to as "component C1"), and a quaternary phosphonium having one or more alkyl groups having from 10 to 18 carbon atoms in the molecule or a salt thereof (hereinafter also referred to as "component C2"). In the present disclosure, "quaternary ammonium having two or more alkyl groups each having from 10 to 18 carbon atoms in the molecule" means, in one or more embodiments, that at least two alkyl groups each having from 10 to 18 carbon atoms are bonded to a nitrogen atom. In the present disclosure, "quaternary phosphonium having one or more alkyl groups each having from 10 to 18 carbon atoms in the molecule" means, in one or more embodiments, that at least one alkyl group each having from 10 to 18 carbon atoms is bonded to a phosphorus atom. From the viewpoint of reducing surface roughness (haze), the number of carbon atoms in the alkyl group is 10 or more, preferably 11 or more, more preferably 12 or more, and 18 or less, preferably 16 or less, and more preferably 15 or less. From the same viewpoint, the number of carbon atoms in the alkyl group is 10 or more and 18 or less, preferably 11 or more and 18 or less, preferably 12 or more and 18 or less, more preferably 12 or more and 16 or less, and even more preferably 12 or more and ... In the case of component C1, the number of alkyl groups having from 10 to 18 carbon atoms contained in the molecule can be 2 or more, 3 or more, or 4, preferably 2 or 3, and more preferably 2. In the case of component C2, the number can be 1 or more, 2 or more, 3 or more, or 4, preferably 1 or 2. Component C may be one type or a combination of two or more types.

[0031] From the viewpoint of reducing surface roughness (haze), the total number of carbon atoms in the molecule of component C is preferably 22 or more, more preferably 24 or more, even more preferably 26 or more, and is preferably 38 or less, more preferably 34 or less, and even more preferably 32 or less. From the same viewpoint, the total number of carbon atoms in the molecule of component C is preferably 22 or more and 38 or less, more preferably 24 or more and 38 or less, even more preferably 26 or more and 38 or less, even more preferably 26 or more and 34 or less, and even more preferably 26 or more and 32 or less.

[0032] In one or more embodiments, from the viewpoint of reducing surface roughness (haze), Component C is preferably a compound having a structure represented by the following formula (I) or (II). [ka]

[0033] In the formula (I), R 1 are the same or different and represent an alkyl group having 10 to 18 carbon atoms; R 2 are the same or different and are hydrocarbon groups having 1 to 6 carbon atoms or -(CH2CH2O) n H (where n is 1 to 3), Z is a phosphorus atom, and X - is the counterion. In the formula (II), R 1 are the same or different and represent an alkyl group having 10 to 18 carbon atoms; R 2 are the same or different and are hydrocarbon groups having 1 to 6 carbon atoms or -(CH2CH2O) n H (where n is 1 to 3), Z is a nitrogen atom or a phosphorus atom, and X - is the counterion. In the formulas (I) and (II), R 2 From the viewpoint of reducing surface roughness (haze), the counter ion is preferably a hydrocarbon group having 1 to 6 carbon atoms. - ), bicarbonate ion (HCO3 - ) etc.

[0034] In one or more embodiments, component C1 can be at least one selected from dialkyldimethylammonium salts (C12-C18 mixed products), didecyldimethylammonium salts, didodecyldimethylammonium salts, ditetradecyldimethylammonium salts, dihexadecyldimethylammonium salts, and dioctadecyldimethylammonium salts. In one or more embodiments, component C2 is at least one selected from alkyl (C12-C18 mixed) trihexyl phosphonium salts, hexadecyl tributyl phosphonium salts, and trihexyl tetradecyl phosphonium salts.

[0035] From the viewpoint of reducing surface roughness (haze), the content of component C in the polishing liquid composition of the present disclosure is preferably 10 ppm or more, more preferably 20 ppm or more, even more preferably 30 ppm or more, and even more preferably 40 ppm or more. From the viewpoint of reducing surface roughness (haze) and dispersibility of the polishing liquid, the content of component C is preferably 40 ppm or less, more preferably 30 ppm or less, and even more preferably 20 ppm or less. From the same viewpoint, the content of component C in the polishing liquid composition of the present disclosure is preferably 10 ppm or more and 40 ppm or less, more preferably 20 ppm or more and 40 ppm or less, and even more preferably 20 ppm or more and 30 ppm or less. When component C is a combination of two or more types, the content of component C refers to the total content thereof.

[0036] [water] In one or more embodiments, the polishing liquid composition of the present disclosure may contain water. Examples of water include ion-exchanged water and ultrapure water, and ultrapure water is preferred from the viewpoint of reducing surface roughness (haze). The content of water in the polishing liquid composition of the present disclosure can be, for example, the remainder of Component A, Component B, Component C, and other components described below.

[0037] [Water-soluble polymer (component D)] In one or more embodiments, the polishing liquid composition of the present disclosure may further contain at least one water-soluble polymer (hereinafter also referred to as "Component D") selected from hydroxyalkyl cellulose, polyglycerin, and a water-soluble polymer having a nitrogen-containing group, from the viewpoint of achieving both wettability and reduced surface roughness (haze). Component D may be one type or a combination of two or more types. In the present disclosure, "water-soluble" refers to a solubility in water (20°C) of 0.5 g / 100 mL or more, preferably 2 g / 100 mL or more. The hydroxyalkyl cellulose may be at least one selected from hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, and hydroxybutyl cellulose. From the viewpoint of achieving both wettability and reduced surface roughness (haze), the water-soluble polymer containing a nitrogen-containing group is preferably an amino group-containing water-soluble polymer containing a structural unit derived from allylamine or diallylamine, and examples thereof include allylamine polymer, allylamine hydrochloride polymer, allylamine hydrochloride-sulfur dioxide copolymer, diallylamine polymer, diallylamine hydrochloride polymer, diallylamine hydrochloride-sulfur dioxide copolymer, allylamine acetate-diallylamine acetate copolymer, allylamine hydrochloride-dimethylallylamine hydrochloride copolymer, methyldiallylamine polymer, and methyldiallylamine hydrochloride polymer. copolymer, methyldiallylamine hydrochloride / sulfur dioxide copolymer, methyldiallylamine / sulfur dioxide copolymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride-sulfur dioxide copolymer, diallyldimethylammonium chloride-acrylamide copolymer, diallylamine amide sulfate-maleic acid copolymer, methyldiallylamine-maleic acid copolymer, diallyldimethylammonium chloride-maleic acid copolymer, and maleic acid-diallyldimethylammonium ethyl sulfate-sulfur dioxide copolymer. Among these, from the viewpoint of achieving both wettability and reduced surface roughness (haze), component D is preferably at least one selected from hydroxyethyl cellulose (HEC), polyglycerin, and methyldiallylamine / sulfur dioxide copolymer.

[0038] When component D is a hydroxyalkyl cellulose, the weight average molecular weight of component D is preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more, from the viewpoint of achieving both wettability and reduced surface roughness (haze), and is preferably 500,000 or less, more preferably 400,000 or less, and even more preferably 300,000 or less. When component D is a polyglycerol, the weight average molecular weight of component D is, from the same viewpoint, preferably 2,000 or more, more preferably 2,500 or more, even more preferably 2,800 or more, and is preferably 10,000 or less, more preferably 8,000 or less, even more preferably 6,000 or less. When component D is a water-soluble polymer containing a nitrogen-containing group, the weight-average molecular weight of component D is, from the same viewpoint, preferably 800 or more, more preferably 1,000 or more, and even more preferably 2,000 or more, and is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 60,000 or less. The weight average molecular weight of Component D can be measured by the method described in the Examples below.

[0039] When the polishing liquid composition of the present disclosure contains component D, the content of component D in the polishing liquid composition of the present disclosure is, from the viewpoint of achieving both wettability and reduced surface roughness (haze), preferably 10 ppm or more, more preferably 30 ppm or more, even more preferably 50 ppm or more, and preferably 1,000 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, and even more preferably 150 ppm or less. From the same viewpoint, the content of component D is preferably 10 ppm or more and 1,000 ppm or less, more preferably 30 ppm or more and 500 ppm or less, even more preferably 50 ppm or more and 300 ppm or less, and even more preferably 50 ppm or more and 150 ppm or less. When component D is a combination of two or more types, the content of component D refers to the total content thereof.

[0040] [Polyethylene glycol (ingredient E)] In one or more embodiments, the polishing liquid composition of the present disclosure may further contain polyethylene glycol (hereinafter also referred to as "component E").

[0041] From the viewpoint of reducing surface roughness (haze), the weight-average molecular weight of Component E is preferably 600 or more, more preferably 800 or more, and even more preferably 1,000 or more, and from the viewpoint of imparting wettability, it is preferably less than 10,000, more preferably 8,000 or less, and even more preferably 6,000 or less. From the viewpoint of imparting wettability, the weight-average molecular weight of Component E is preferably 600 or more and less than 10,000, preferably 800 or more and 8,000 or less, and even more preferably 1,000 or more and 6,000 or less. Component E may be one type or a combination of two or more types.

[0042] When the polishing composition of the present disclosure contains component E, the content of component E in the polishing composition of the present disclosure is preferably 0.1 ppm or more, more preferably 1 ppm or more, and even more preferably 3 ppm or more from the viewpoint of reducing surface roughness (haze), and is preferably 1,000 ppm or less, more preferably 500 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, and even more preferably 30 ppm or less from the viewpoint of imparting wettability. From the viewpoint of achieving both a reduction in surface roughness (haze) and imparting wettability, the content of component E in the polishing composition of the present disclosure is preferably 0.1 ppm or more and 1,000 ppm or less, more preferably 1 ppm or more and 500 ppm or less, more preferably 3 ppm or more and 100 ppm or less, even more preferably 3 ppm or more and 50 ppm or less, and even more preferably 3 ppm or more and 30 ppm or less. When component E is a combination of two or more types, the content of component E refers to the total content thereof.

[0043] [Other ingredients] The polishing liquid composition of the present disclosure may further contain other components to the extent that the effects of the present disclosure are not impaired. In one or more embodiments, the other components include at least one selected from a pH adjuster other than Component B, a surfactant other than Component C, a water-soluble polymer other than Component D and Component E, a preservative, an alcohol, a chelating agent, and an oxidizing agent.

[0044] From the viewpoint of reducing surface roughness (haze), the pH of the polishing composition of the present disclosure is preferably 9 or more, more preferably 9.5 or more, even more preferably 10 or more, and preferably 12 or less, more preferably 11.5 or less, and even more preferably 11 or less. From the same viewpoint, the pH of the polishing composition of the present disclosure is preferably 9 or more and 12 or less, more preferably 9.5 or more and 11.5 or less, and even more preferably 10 or more and 11 or less. The pH of the polishing composition of the present disclosure can be adjusted using component B or a known pH adjuster. In the present disclosure, the above pH is a value measured by the method described in the Examples.

[0045] The polishing liquid composition of the present disclosure can be produced, for example, by blending components A, B, and C, and, if desired, optional components (component D, component E, and other components) using a known method. That is, in another aspect, the present disclosure relates to a method for producing a polishing liquid composition, comprising blending at least components A, B, and C. In the present disclosure, "blending" includes mixing components A, B, and C, and, if necessary, optional components (component D, component E, and other components), simultaneously or in any order. The blending can be carried out using, for example, a stirrer such as a homomixer, homogenizer, ultrasonic disperser, wet ball mill, or bead mill. The preferred blend amounts of each component in the method for producing a polishing liquid composition of the present disclosure can be the same as the preferred contents of each component in the polishing liquid composition of the present disclosure described above.

[0046] In the present disclosure, the "content of each component in the polishing composition" refers to the content of each component at the time of use, that is, at the time when the polishing composition begins to be used for polishing.

[0047] The polishing liquid composition of the present disclosure may be produced as a concentrate from the viewpoints of storage and transportation, and diluted at the time of use. The dilution ratio is preferably 2 times or more, more preferably 10 times or more, even more preferably 30 times or more, and even more preferably 50 times or more from the viewpoints of production and transportation costs and storage stability, and is preferably 180 times or less, more preferably 140 times or less, even more preferably 100 times or less, and even more preferably 70 times or less from the viewpoint of storage stability. The polishing liquid composition concentrate of the present disclosure can be used by diluting it with water so that the contents of each component are the above-mentioned contents (i.e., the contents at the time of use) at the time of use. In the present disclosure, the "time of use" of the polishing liquid composition concentrate refers to the diluted state of the polishing liquid composition concentrate.

[0048] [Silicon substrate to be polished] In one or more embodiments, the polishing composition of the present disclosure is a polishing composition for silicon substrates and can be used, for example, in a polishing step of polishing a silicon substrate in a method for producing a semiconductor substrate, or in a polishing step of polishing a silicon substrate in a method for polishing a silicon substrate. In one or more embodiments, the silicon substrate to be polished using the polishing composition of the present disclosure may be a silicon substrate, and in one or more embodiments, a single crystal silicon substrate or a polysilicon substrate. Furthermore, from the viewpoint of achieving both an improved polishing rate and reduced surface roughness (haze), the resistivity of the silicon substrate is preferably 0.0001 Ω·cm or more, more preferably 0.001 Ω·cm or more, even more preferably 0.01 Ω·cm or more, and even more preferably 0.1 Ω·cm or more, and is preferably 100 Ω·cm or less, more preferably 50 Ω·cm or less, and even more preferably 20 Ω·cm or less.

[0049] [Polishing liquid kit] In another aspect, the present disclosure relates to a polishing liquid kit for producing the polishing liquid composition of the present disclosure (hereinafter, sometimes abbreviated as the "kit of the present disclosure"). The kit of the present disclosure can produce a polishing liquid composition that can reduce surface roughness (haze). In one or more embodiments, the kit of the present disclosure includes a polishing liquid kit containing a solution containing component A, component B, and component C. The solution may contain the optional components described above (component D, component E, and other components) as needed. The solution may be diluted with water as needed before use.

[0050] [Silicon substrate polishing method] In another aspect, the present disclosure relates to a method for polishing a silicon substrate (hereinafter also referred to as the polishing method of the present disclosure), which includes a step of polishing a silicon substrate to be polished using the polishing composition of the present disclosure (hereinafter also referred to as the "polishing step"). According to the polishing method of the present disclosure, the polishing composition of the present disclosure is used, thereby making it possible to reduce surface roughness (haze).

[0051] In the polishing step of the polishing method of the present disclosure, for example, the silicon substrate to be polished can be pressed against a platen to which a polishing pad is attached, and the silicon substrate can be polished at a polishing pressure of 3 to 20 kPa. In the present disclosure, the polishing pressure refers to the pressure of the platen applied to the surface to be polished of the silicon substrate to be polished during polishing.

[0052] In the polishing step of the polishing method of the present disclosure, for example, the silicon substrate to be polished can be pressed against a platen to which a polishing pad is attached, and the silicon substrate to be polished can be polished with a polishing liquid composition and a polishing pad surface temperature of 15° C. to 40° C. From the viewpoint of reducing surface roughness (haze), the temperature of the polishing liquid composition and the polishing pad surface temperature are preferably 15° C. or higher or 20° C. or higher, and preferably 40° C. or lower or 30° C. or lower.

[0053] [Method of manufacturing semiconductor substrate] In another aspect, the present disclosure relates to a method for manufacturing a semiconductor substrate (hereinafter also referred to as the "semiconductor substrate manufacturing method of the present disclosure"), which includes a step of polishing a silicon substrate to be polished using the polishing liquid composition of the present disclosure (hereinafter also referred to as the "polishing step") and a step of cleaning the polished silicon substrate (hereinafter also referred to as the "cleaning step"). According to the semiconductor substrate manufacturing method of the present disclosure, the use of the polishing liquid composition of the present disclosure can reduce surface roughness (haze), allowing high-quality semiconductor substrates to be manufactured with high yield and good productivity.

[0054] The polishing step in the semiconductor substrate manufacturing method of the present disclosure can include, for example, a lapping (rough polishing) step of planarizing a single crystal silicon substrate obtained by slicing a single crystal silicon ingot into a thin disk, and a finish polishing step of etching the lapped single crystal silicon substrate and then mirror-finishing the surface of the single crystal silicon substrate. From the viewpoint of reducing surface roughness (haze), the polishing composition of the present disclosure is more preferably used in the finish polishing step.

[0055] The polishing step in the semiconductor substrate manufacturing method of the present disclosure can be performed under the same conditions (polishing pressure, polishing liquid composition and surface temperature of polishing pad, etc.) as those in the polishing step in the polishing method of the present disclosure described above.

[0056] In one or more embodiments, the method for manufacturing a semiconductor substrate according to the present disclosure may include a dilution step of diluting the concentrate of the polishing liquid composition according to the present disclosure prior to the polishing step. The diluent may be, for example, water.

[0057] In the cleaning step of the semiconductor substrate manufacturing method of the present disclosure, inorganic cleaning is preferably performed from the viewpoint of reducing residues on the silicon substrate surface. Examples of cleaning agents used in inorganic cleaning include inorganic cleaning agents containing at least one selected from hydrogen peroxide, ammonia, hydrochloric acid, sulfuric acid, hydrofluoric acid, and ozone water.

[0058] In one or more embodiments, the semiconductor substrate manufacturing method of the present disclosure can further include, after the cleaning step, a step of rinsing the cleaned silicon substrate with water and drying it. [Example]

[0059] Hereinafter, the present disclosure will be described in more detail with reference to examples, but these are merely illustrative examples and the present disclosure is not limited to these examples.

[0060] 1. Preparation of Polishing Compositions (Examples 1 to 13 and Comparative Examples 1 to 9) Polishing liquid compositions of Examples 1 to 13 and Comparative Examples 1 to 9 were obtained by stirring and mixing silica particles (component A), ammonia (component B), a cationic surfactant (component C or non-component C) shown in Table 1, a water-soluble polymer (component D), polyethylene glycol (component E), and ultrapure water shown in Table 1. The content of each component in Table 1 is the content (mass % or mass ppm, active ingredient) of each component at the time of use of the polishing liquid composition. The content of ultrapure water is the remainder excluding components A, B, and C or non-component C, D, and E. The pH of each polishing liquid composition (at use) was 10 at 25°C.

[0061] The following components A, B, C, non-component C, D, and E were used to prepare each polishing composition. (Component A) Colloidal silica [average primary particle size 25 nm, average secondary particle size 49 nm, degree of association 2.0] Colloidal silica [average primary particle size 35 nm, average secondary particle size 70 nm, degree of association 2.0] (Component B) Ammonia [28% by mass ammonia water, Kishida Chemical Co., Ltd., special grade reagent] (Component C) Didodecyldimethylammonium chloride [manufactured by Tokyo Chemical Industry Co., Ltd.] (in formula (II), R 1 :C 12 H 25 , R 2 :CH3, Z:N, X:Cl - ) Dialkyl(C12-18)dimethylammonium chloride [Kao Corporation, Kohtamin D2345P] (in formula (II), R 1 : C12-18 alkyl group, R 2 :CH3, Z:N, X:Cl - ) Dimethyldioctadecylammonium chloride [manufactured by Tokyo Chemical Industry Co., Ltd.] (in formula (II), R 1 :C 18 H 37 , R 2 :CH3, Z:N, X:Cl - ) Didecyldimethylammonium bicarbonate [Carboquat HE, manufactured by Lonza Japan] (in formula (II), R 1 :C 10 H 21 , R 2 :CH3, Z:N, X:HCO3 - ) Trihexyltetradecylphosphonium chloride [manufactured by Tokyo Chemical Industry Co., Ltd.] (in formula (I), R 1 :C 14 H 29 , R 2 :C6H 13 , Z:P, X:Cl - ) (Non-ingredient C) Hexadecyltrimethylammonium chloride [Tokyo Chemical Industry Co., Ltd.] TBAH [tetrabutylammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd.] TMAH [tetramethylammonium hydroxide, manufactured by Tokyo Chemical Industry Co., Ltd.] (Component D) Polyglycerin [Daicel Corporation, XPW, degree of polymerization 40, weight-average molecular weight 2,980] HEC [hydroxyethyl cellulose, manufactured by Daicel Corporation, SE400, weight-average molecular weight 250,000] PAS2201 [Methyldiallylamine-sulfur dioxide copolymer, manufactured by Nittobo Medical Co., Ltd., weight-average molecular weight 3,000] (Component E) PEG 1000 [Polyethylene glycol, NOF Corporation, PEG#1000, weight-average molecular weight 1,000] PEG 6000 [Polyethylene glycol, NOF Corporation, PEG#6000, weight-average molecular weight 6,000]

[0062] 2.Measuring methods for various parameters (1) Measurement of the average primary particle size of silica particles (component A) The average primary particle diameter (nm) of component A is calculated by the BET (nitrogen adsorption) method. 2 / g) was calculated using the following formula. Average primary particle diameter (nm)=2727 / S

[0063] The specific surface area S of component A was measured by the nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritic automatic specific surface area measuring device "Flowsorb III2305", manufactured by Shimadzu Corporation) after carrying out the following [pretreatment]. Approximately 0.1 g of the measurement sample was weighed out to four decimal places into a measuring cell, and the sample was dried for 30 minutes in an atmosphere at 110°C immediately before measuring the specific surface area. [Preprocessing] (a) Adjust the pH of the slurry of component A to 2.5±0.1 with an aqueous solution of nitric acid. (b) The slurry of component A adjusted to pH 2.5±0.1 is placed in a petri dish and dried in a hot air dryer at 150°C for 1 hour. (c) After drying, the obtained sample is finely crushed in an agate mortar. (d) The crushed sample is suspended in ion-exchanged water at 40°C and filtered through a membrane filter with a pore size of 1 μm. (e) The residue on the filter is washed five times with 20 g of ion-exchanged water (40°C). (f) The filter with the filtrate attached thereto is placed in a petri dish and dried in an atmosphere of 110°C for 4 hours. (g) The dried filtrate (component A) was taken out, being careful not to mix in any filter debris, and finely crushed in a mortar to obtain a measurement sample.

[0064] (2) Average secondary particle size of silica particles (component A) The average secondary particle diameter (nm) of component A was measured by adding an abrasive to ion-exchanged water so that the concentration of component A was 0.25% by mass, and then placing the resulting aqueous dispersion in a disposable sizing cuvette (a 10 mm polystyrene cell) to a height of 10 mm from the bottom, using dynamic light scattering (apparatus name: Zetasizer Nano ZS, manufactured by Sysmex Corporation).

[0065] (3) Measurement of the weight-average molecular weight of water-soluble polymers (components D and E) The weight-average molecular weights of the water-soluble polymers (component D, component E) were calculated based on peaks in a chromatogram obtained by applying gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Apparatus: HLC-8320 GPC (Tosoh Corporation, detector integrated) Column: α-M + α-M Eluent: 0.15 mol / L Na2SO4, 1% by mass acetic acid, solvent: water Flow rate: 1.0mL / min Column temperature: 40℃ Detector: Shodex RI SE-61 differential refractive index detector Standard material: pullulan with known molecular weight

[0066] 3. Polishing method etc. Each polishing composition was filtered with a filter (compact cartridge filter "MCP-LX-C10S", manufactured by Advantech Co., Ltd.) immediately before polishing, and the following silicon substrates were subjected to finish polishing and cleaning under the following polishing conditions. <Silicon substrate to be polished> Single-crystal silicon substrate [200 mm diameter silicon single-sided mirror-finished substrate, conductivity type: P, crystal orientation: 100, resistivity: 0.1 Ω·cm or more but less than 100 Ω·cm] The single crystal silicon substrate was previously subjected to rough polishing using a commercially available polishing composition. The haze of the single crystal silicon substrate subjected to finish polishing after rough polishing was 2 to 3 ppm. The haze was measured using a dark field wide grazing incidence channel (DWO) using a KLA Tencor "Surfscan SP1-DLS."

[0067] <Finishing polishing conditions> Polishing machine: Single-sided 8-inch polishing machine "GRIND-X SPP600s" (manufactured by Okamoto Kogyo) Polishing pad: Suede pad (manufactured by Toray Cortex, Asker hardness: 64, thickness: 1.37 mm, nap length: 450 μm, opening diameter: 60 μm) Silicon substrate polishing pressure: 100g / cm 2 Plate rotation speed: 60 rpm Polishing time: 5 minutes Polishing composition supply rate: 150 g / min Temperature of polishing composition: 23°C Carrier rotation speed: 62 rpm

[0068] <Cleaning method> After the finish polishing, the silicon substrate was subjected to ozone cleaning and dilute hydrofluoric acid cleaning as follows. For the ozone cleaning, an aqueous solution containing 20 ppm ozone was sprayed from a nozzle at a flow rate of 1 L / min toward the center of the silicon substrate rotating at 600 rpm for 3 minutes. The ozone water was kept at room temperature during this process. Next, dilute hydrofluoric acid cleaning was performed. For the dilute hydrofluoric acid cleaning, an aqueous solution containing 0.5 mass% ammonium hydrogen fluoride (special grade, Nakarai Tesque, Inc.) was sprayed from a nozzle at a flow rate of 1 L / min toward the center of the silicon substrate rotating at 600 rpm for 6 seconds. Two sets of the above ozone cleaning and dilute hydrofluoric acid cleaning were performed, and finally, spin drying was performed. For spin drying, the silicon substrate was rotated at 1,500 rpm.

[0069] 4. Evaluation [Evaluation of surface roughness (haze) of silicon substrates] To evaluate the surface roughness (haze) of the silicon substrate surface after cleaning, the value (DWO haze) measured using the dark field wide grazing incidence channel (DWO) using the surface roughness measuring device "Surfscan SP1-DLS" (KLA Tencor) was used. The smaller the DWO haze value, the smoother the surface. The surface roughness (haze) was measured for two silicon substrates and the average value was calculated. The results are shown in Table 1.

[0070] [Table 1]

[0071] As shown in Table 1, it was found that the polishing compositions of Examples 1 to 13 were able to reduce haze compared to the polishing compositions of Comparative Examples 1 to 9. [Industrial Applicability]

[0072] Use of the polishing composition of the present disclosure can reduce surface roughness (haze), and is therefore useful as a polishing composition used in the production processes of various semiconductor substrates, and is particularly useful as a polishing composition for finish polishing of silicon substrates.

Claims

1. A polishing composition for silicon substrates comprising the following component A, component B, component C, and component E: Component A: Silica particles Component B: One or two selected from ammonia and hydroxyamine Component C: At least one cationic surfactant selected from the group consisting of a quaternary ammonium or salt thereof having two or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C1), and a quaternary phosphonium or salt thereof having one or more alkyl groups having 10 to 18 carbon atoms in the molecule (component C2). Component E: Polyethylene glycol

2. 2. The polishing composition according to claim 1, wherein the total number of carbon atoms in the molecule of Component C is 22 or more and 38 or less.

3. 3. The polishing composition according to claim 1, wherein Component C is a compound represented by the following formula (I) or (II): 【Chemical 1】 In the formula (I), R 1 are the same or different and represent an alkyl group having 10 to 18 carbon atoms; R 2 are the same or different and each represents a hydrocarbon group having 1 to 6 carbon atoms or -(CH 2 CH 2 O) n H (where n is 1 to 3), Z is a phosphorus atom, and X - is the counterion. In the formula (II), R 1 are the same or different and represent an alkyl group having 10 to 18 carbon atoms; R 2 are the same or different and each represents a hydrocarbon group having 1 to 6 carbon atoms or -(CH 2 CH 2 O) n H (where n is 1 to 3), Z is a nitrogen atom or a phosphorus atom, and X - is the counterion.

4. 4. The polishing composition according to claim 1, wherein the average primary particle size of Component A is 25 nm or more and 35 nm or less.

5. The polishing composition according to claim 1 , wherein Component B is ammonia.

6. 6. The polishing composition according to claim 1, further comprising at least one water-soluble polymer (component D) selected from the group consisting of hydroxyalkyl cellulose, polyglycerin, and a water-soluble polymer containing a nitrogen-containing group.

7. A method for polishing a silicon substrate, comprising the step of polishing a silicon substrate to be polished with the polishing composition according to claim 1 .

8. A step of polishing a silicon substrate to be polished using the polishing composition according to any one of claims 1 to 6; and cleaning the polished silicon substrate.

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