A polishing liquid composition for a silicon substrate

Abstract

To provide, in one aspect, a polishing liquid composition for a silicon substrate which can achieve increase in the polishing speed, reduction in the surface roughness (haze) of the silicon substrate, and the storage stability of a concentrate.SOLUTION: In one aspect, a polishing liquid composition for a silicon substrate contains the component A, the component B and the component D, and has a pH greater than 8.5 and less than or equal to 14, where the component A is silica particles, the component B is an amino group-containing water-soluble polymer with a pKa from 5 to 8.5 inclusive, and the component D is a nonionic water-soluble polymer.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] As a polishing liquid composition used for polishing a silicon substrate used in the manufacture of a semiconductor substrate, a polishing liquid composition containing silica particles is known. In this type of polishing liquid composition, the occurrence of surface defects (LPD: Light point defects) of the silicon substrate due to the aggregation of silica particles and the clogging of the filter when filtering the polishing liquid composition to remove aggregates are problems (for example, see Patent Document 1). Further, for the purpose of improving the polishing rate, a polishing liquid composition containing a water-soluble polymer compound is known (see Patent Documents 2 and 3).

[0003] Patent Document 1 proposes a polishing liquid composition containing silica particles, a nitrogen-containing basic compound, and a water-soluble polymer having a ratio of the number of oxygen atoms derived from a hydroxyl group to the number of oxygen atoms derived from polyoxyalkylene of 0.8 to 10. Patent Document 2 proposes a polishing liquid composition containing a water-soluble polymer compound containing a nitrogen-containing group such as polyethyleneimine. Patent Document 3 proposes a semiconductor polishing composition containing abrasive grains, a basic compound, and two or more water-soluble polymers, and the water-soluble polymer contains a cationic water-soluble polymer containing a nitrogen-containing group. Examples of this document describe a semiconductor polishing composition containing colloidal silica, ammonia, tetramethylammonium hydroxide, hydroxyethyl cellulose having a weight average molecular weight of 800,000, and polyethyleneimine.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] However, in polishing using the polishing liquid composition of Patent Document 1, the polishing rate is not sufficient. When using the polishing liquid composition of Patent Document 2, there is a problem that silica particles aggregate due to a water-soluble polymer compound containing a nitrogen-containing group, and surface defects of the silicon substrate such as the generation of scratches deteriorate. When using the polishing liquid composition of Patent Document 3, the reduction of surface roughness (haze) is not sufficient, and aggregates of silica particles are likely to occur. Moreover, even if the polishing liquid composition is filtered, it immediately causes clogging of the filter, so there is a problem that the polishing liquid composition cannot be filtered immediately before polishing. Furthermore, usually, the polishing liquid composition is stored and transported in a concentrated state, and storage stability in the concentrated state is also required.

[0006] The present disclosure provides a polishing liquid composition for a silicon substrate, a method for polishing a silicon substrate using the same, and a method for manufacturing a semiconductor substrate, which can achieve an improvement in polishing rate, a reduction in surface roughness (haze) of the silicon substrate, and storage stability of the concentrate. [Means for Solving the Problems

[0007] In one aspect, the present disclosure relates to a polishing liquid composition for a silicon substrate, which contains the following component A, the following component B, and the following component D, and has a pH of more than 8.5 and 14 or less. Component A: Silica particles Component B: An amino group-containing water-soluble polymer having a pKa of 5 or more and 8.5 or less Component D: A nonionic water-soluble polymer

[0008] In one aspect, the present disclosure relates to a method for polishing a silicon substrate, which includes a step of polishing a silicon substrate to be polished using the polishing liquid composition of the present disclosure.

[0009] In one aspect, the present disclosure relates to a method for manufacturing a semiconductor substrate, which includes a step of polishing a silicon substrate to be polished using the polishing liquid composition of the present disclosure and a step of cleaning the polished silicon substrate.

Effects of the Invention

[0010] According to the present disclosure, it is possible to provide a polishing liquid composition for a silicon substrate capable of achieving an improvement in polishing rate, a reduction in surface roughness (haze) of the silicon substrate, and storage stability of the concentrate, a method for polishing a silicon substrate using the polishing liquid composition, and a method for manufacturing a semiconductor substrate.

Modes for Carrying Out the Invention

[0011] The present disclosure is based on the finding that by using a polishing liquid composition for a silicon substrate containing silica particles, an amino group-containing water-soluble polymer having a pKa of 5 or more and 8.5 or less, and a nonionic water-soluble polymer, and having a pH of more than 8.5 and 14 or less, the silicon substrate can be polished at high speed, the surface roughness (haze) of the silicon substrate can be reduced, and the storage stability of the concentrate is excellent.

[0012] That is, in one aspect, the present disclosure relates to a polishing liquid composition for a silicon substrate (hereinafter, also referred to as "the polishing liquid composition of the present disclosure") containing the following component A, the following component B, and the following component D and having a pH of more than 8.5 and 14 or less. Component A: Silica particles Component B: An amino group-containing water-soluble polymer having a pKa of 5 or more and 8.5 or less Component D: A nonionic water-soluble polymer

[0013] According to the present disclosure, in one or more embodiments, it is possible to achieve both an improvement in polishing rate, a reduction in surface roughness (haze) of the silicon substrate, and storage stability of the concentrate.

[0014] Although the detailed mechanism of the effect manifestation of the present disclosure is not clear, it is presumed as follows. Under alkaline polishing conditions where the pH is greater than 8.5 and less than or equal to 14, both the silica abrasive grains and the silicon substrate to be polished have negative charges, and an electrostatic repulsive force is always generated. To improve the polishing rate, it is effective to relax this electrostatic repulsion, and the negative charges on both surfaces can be relaxed by a cationic substance. However, if this is done, a new problem will occur, that is, aggregation between silica particles will occur, and the storage stability of the polishing liquid composition, particularly the storage stability of the concentrate of the polishing liquid composition, will decrease. Therefore, paying attention to the water-soluble polymer having an amino group, the amino group-containing water-soluble polymer (Component B) having a pKa smaller than the pH of the abrasive composition has low cationicity and is considered to adsorb on the silica particles (Component A) and the silicon substrate to be polished mainly by the van der Waals force of the whole molecule rather than the electrostatic interaction with the amino group. Therefore, it is considered that the amino group-containing water-soluble polymer (Component B) can moderately relax the electrostatic repulsive force between the silica particles (Component A) and the silicon substrate to be polished, suppress the aggregation of the silica particles, and achieve both an improvement in the polishing rate and storage stability. In addition, the amino group-containing water-soluble polymer (Component B) having a pKa of 5 or more and 8.5 or less, when used in combination with the nonionic water-soluble polymer (Component D), is considered to improve the surface roughness (haze) by suppressing the corrosion of the silicon substrate by the thick adsorption of two types of water-soluble polymers on the surface of the silicon substrate to be polished. However, the present disclosure may not be construed as being limited to these mechanisms.

[0015] [Silicon substrate to be polished] The polishing liquid composition of the present disclosure is a polishing composition for a silicon substrate, and can be used, for example, in a polishing step of polishing a silicon substrate to be polished in a method for manufacturing a semiconductor substrate or in a polishing step of polishing a silicon substrate to be polished in a method for polishing a silicon substrate. As the silicon substrate to be polished polished using the polishing liquid composition of the present disclosure, in one or more embodiments, a silicon substrate or the like can be mentioned, and in one or more embodiments, a single crystal silicon substrate, a polysilicon substrate, a substrate having a polysilicon film, a SiN substrate, etc. can be mentioned. From the viewpoint of exerting the effects of the polishing liquid composition of the present disclosure, a single crystal silicon substrate or a polysilicon substrate is preferable, and a single crystal silicon substrate is more preferable.

[0016] [Silica particles (Component A)] The polishing liquid 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, or silica obtained by surface-modifying them. From the viewpoint of achieving both an improvement in polishing rate and storage stability, and an improvement in surface quality such as reduction of surface roughness (haze), surface defects, and scratches, colloidal silica is preferable. Component A may be of one type or a combination of two or more types.

[0017] From the viewpoint of operability, the form of use of Component A is preferably in the form of 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 the silicon substrate by an alkali metal, an alkaline earth metal, or the like, it is preferable that the colloidal silica is 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 perspective of maintaining the polishing rate, the average primary particle diameter of Component A is preferably 10 nm or more, more preferably 15 nm or more, still more preferably 20 nm or more. From the perspectives of improving storage stability and improving surface quality such as reducing surface roughness (haze), surface defects, and scratches, it is preferably 50 nm or less, more preferably 45 nm or less, still more preferably 40 nm or less, and still more preferably 30 nm or less. From the same perspectives, the average primary particle diameter of Component A is preferably 10 nm or more and 50 nm or less, more preferably 15 nm or more and 45 nm or less, still more preferably 20 nm or more and 40 nm or less, and preferably 20 nm or more and 30 nm or less. In the present disclosure, the average primary particle diameter of Component A is calculated using the specific surface area S (m 2 / g) calculated by the nitrogen adsorption method (BET method). The value of the average primary particle diameter is the value measured by the method described in the examples.

[0019] From the perspective of maintaining the polishing rate, the average secondary particle diameter of Component A is preferably 20 nm or more, more preferably 30 nm or more, still more preferably 40 nm or more. From the perspectives of improving storage stability and improving surface quality such as reducing surface roughness (haze), surface defects, and scratches, it is preferably 100 nm or less, more preferably 90 nm or less, still more preferably 80 nm or less, still more preferably 70 nm or less, and still more preferably 60 nm or less. From the same perspectives, the average secondary particle diameter of Component A is preferably 20 nm or more and 100 nm or less, more preferably 30 nm or more and 90 nm or less, still more preferably 30 nm or more and 80 nm or less, still more preferably 30 nm or more and 70 nm or less, and still more preferably 40 nm or more and 60 nm or less. In the present disclosure, the average secondary particle diameter is a value measured by the dynamic light scattering (DLS) method and is the value measured by the method described in the examples.

[0020] The degree of aggregation of Component A is preferably 3 or less, more preferably 2.5 or less, still more preferably 2.3 or less, from the viewpoints of improving storage stability and surface quality. From the viewpoints of achieving both improved polishing rate and storage stability and improving surface quality, it is preferably 1.1 or more, more preferably 1.5 or more, still more preferably 1.8 or more.

[0021] In the present disclosure, the degree of aggregation of Component A is a coefficient representing the shape of silica particles and is calculated by the following formula. Degree of aggregation = average secondary particle diameter / average primary particle diameter

[0022] As a method for adjusting the degree of aggregation of Component A, for example, the methods described in JP-A-6-254383, JP-A-11-214338, JP-A-11-60232, JP-A-2005-060217, JP-A-2005-060219, etc. can be adopted.

[0023] The shape of Component A is preferably a so-called spherical shape and / or a so-called mayu shape from the viewpoints of achieving both improved polishing rate and storage stability and improving surface quality.

[0024] The content of Component A in the polishing liquid composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.07% by mass or more, even more preferably 0.1% by mass or more, in terms of SiO2, from the viewpoint of improving the polishing rate. From the viewpoints of improving storage stability and surface quality, it is preferably 2.5% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, even more preferably 0.2% by mass or less. Therefore, the content of Component A in the polishing liquid composition of the present disclosure is preferably 0.01% by mass or more and 2.5% by mass or less, more preferably 0.05% by mass or more and 1% by mass or less, still more preferably 0.07% by mass or more and 0.8% by mass or less, even more preferably 0.07% by mass or more and 0.5% by mass or less, even more preferably 0.07% by mass or more and 0.3% by mass or less, even more preferably 0.07% by mass or more and 0.2% by mass or less. When there are two or more combinations of Component A, the content of Component A refers to their total content.

[0025] [Amino group-containing water-soluble polymer (Component B) with a pKa of 5 or more and 8.5 or less] The polishing liquid composition of the present disclosure contains an amino group-containing water-soluble polymer (hereinafter also referred to as "Component B") having a pKa of 5 or more and 8.5 or less. Component B is considered to be able to adjust the zeta potential of the silica particles (Component A) and the silicon substrate to be polished, reduce the electrostatic repulsive force between the silica particles (Component A) and the silicon substrate to be polished, and suppress the aggregation of the silica particles. In the present disclosure, "water-soluble" means having a solubility of 0.5 g / 100 mL or more, preferably 2 g / 100 mL or more, in water (20°C).

[0026] From the viewpoint of improving the polishing rate, the pKa of Component B is 5 or more, preferably 5.5 or more, more preferably 5.9 or more, still more preferably 6.3 or more, and from the viewpoint of improving the surface quality, it is 8.5 or less, preferably 8.3 or less, more preferably 8.1 or less, still more preferably 8 or less. Furthermore, when Component B is Component B1 described below, from the viewpoint of improving the polishing rate, the pKa of Component B is more preferably 6.4 or more, and from the viewpoint of improving the surface quality, it is more preferably 7.7 or less, more preferably 7.4 or less, still more preferably 7.1 or less. Furthermore, when Component B is Component B2 described below, from the viewpoint of improving the polishing rate, the pKa of Component B is more preferably 6.6 or more, more preferably 6.9 or more, still more preferably 7.1 or more, and from the viewpoint of improving the surface quality, it is more preferably 7.8 or less, more preferably 7.6 or less, still more preferably 7.4 or less.

[0027] As component B, from the viewpoint of achieving both improved polishing rate and storage stability, it preferably contains structural units derived from one or more monomers selected from allylamine and diallylamine. From the viewpoint of availability, in one or more embodiments, component B is preferably an amino group-containing water-soluble polymer containing structural units derived from allylamine (hereinafter also referred to as "component B1"), and in one or more embodiments, it is preferably an amino group-containing water-soluble polymer containing structural units derived from diallylamine (hereinafter also referred to as "component B2").

[0028] (Component B1: Amino group-containing water-soluble polymer containing structural units derived from allylamine) In one or more embodiments, at least a part of the amino groups in the structural units derived from allylamine preferably has a steric shielding group from the viewpoints of achieving both improved polishing rate and storage stability and availability. In the present disclosure, the steric shielding group refers to a steric (bulky) substituent that can shield the nitrogen atom of the amino group of component B to suppress cationization, that is, lower the pKa. From the same viewpoints, the amino group having the steric shielding group is preferably a secondary amino group or a tertiary amino group containing a hydrocarbon group having 3 to 11 carbon atoms and having a hydroxyl group. The number of carbon atoms of the hydrocarbon group is preferably 3 or more from the viewpoint of improving the shielding property of the amino group (suppressing the cationization of the nitrogen atom of the amino group) and the viewpoint of achieving both improved polishing rate and storage stability, and preferably 11 or less, more preferably 7 or less, still more preferably 5 or less, and even more preferably 4 or less from the viewpoints of improving water solubility and availability.

[0029] The amino group having the steric shielding group is, in one or more embodiments, a modifying group of the amino group with a glycidol derivative, and in one or more embodiments, is a group formed by the reaction of the amino group in the structural unit derived from allylamine and the glycidol derivative. At least a part of the amino groups among all the amino groups of Component B1 are modified with a glycidol derivative to become an amino group having a steric shielding group. The equivalent amount of the glycidol derivative with respect to the number of amino groups (1 equivalent) in the structural unit derived from allylamine (hereinafter, also referred to as "glycidol modification rate") is preferably 0.3 or more, more preferably 0.5 or more, still more preferably 0.8 or more, still more preferably 1 or more, preferably more than 1.1, more preferably 1.2 or more, still more preferably 1.3 or more, still more preferably 1.4 or more, still more preferably 1.5 or more, from the viewpoint of improving storage stability and from the viewpoint of improving surface quality, and preferably 4 or less, more preferably 3 or less, still more preferably 2.5 or less, still more preferably 2 or less, still more preferably 1.9 or less, still more preferably 1.6 or less, from the viewpoint of improving polishing rate.

[0030] In the present disclosure, the glycidol modification rate is 13 a value measured by the method described in the examples using C-NMR. However, the glycidol modification rate can also be measured by the following method (1) or (2). (1) It can be determined from the amino group equivalent of the allylamine polymer used as the reaction raw material and the number of moles of the glycidol derivative. (2) Measure the nitrogen content N (mass%) of the reaction product of the glycidol derivative and the allylamine polymer, and it can be determined from the following formula. Glycidol modification rate = A / B Here, A = (100 - N × molecular weight of allylamine monomer / 14) / molecular weight of glycidol derivative, and B = N / 14.

[0031] Examples of the glycidol derivative include glycidol, alkyl glycidyl ether, etc. From the viewpoints of availability, and achieving both improved polishing rate and storage stability, glycidol is preferred. From the viewpoint of availability, the alkyl group of the alkyl glycidyl ether preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a 2-ethylhexyl group. Examples of the alkyl glycidyl ether include methyl glycidyl ether and 2-ethylhexyl glycidyl ether.

[0032] In one or more embodiments, component B1 includes polyallylamine in which at least some of the amino groups have a steric shielding group, and in one or more embodiments, a reaction product of polyallylamine and a glycidol derivative.

[0033] In one or more embodiments, component B1 includes a compound (glycidol-modified polyallylamine) containing a structural unit of the following formula (I).

Chemical formula

[0034] In formula (I), R 1 and R 2 are each a hydrogen atom or a steric shielding group. Examples of the steric shielding group include a modifying group derived from a glycidol derivative. In one or more embodiments, a 1-mole adduct or 2-mole adduct of glycidol is included. In one or more embodiments, -CH2CH(OH)CH2(OH), -CH2CH(OH)CH2O-CH2CH(OH)CH2(OH), etc. are included.

[0035] (Component B2: Amino group-containing water-soluble polymer containing a structural unit derived from diallylamine) In one or more embodiments, at least a part of the amino groups in the structural units derived from diallylamine preferably has an electron-withdrawing group at the β-position or γ-position of the amino group from the viewpoint of achieving both an improvement in polishing rate and storage stability. Examples of the electron-withdrawing group include a group represented by the following formula (II).

[0036]

Chemical formula

[0037] In one or more embodiments, Component B2 includes compounds containing structural units derived from diallylamine and structural units derived from sulfur dioxide. For example, compounds containing structural units represented by the following formula (III) are included.

Chemical formula

[0038] In formula (III), R 3 is an alkyl group having 1 to 3 carbon atoms which may have a hydroxyl group. From the viewpoints of availability and economy, R 3 is preferably a methyl group. Also, n + m = 1, and n and m are 0 or 1. From the same viewpoints, compounds with m = 1 and n = 0 are preferred. Note that a mixture of compounds with m = 1 and n = 0 and compounds with m = 0 and n = 1 may also be used.

[0039] In one or more embodiments, Component B2 includes compounds containing structural units represented by the following formula (IV). For example, a methyl diallylamine / sulfur dioxide copolymer is included.

Chemical formula

[0040] From the viewpoint of improving the polishing rate, the weight average molecular weight of Component B is preferably 800 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still more preferably 2,000 or more. From the viewpoints of achieving both improvement in the polishing rate and storage stability, and reducing surface roughness and surface defects, it is preferably 100,000 or less, more preferably 60,000 or less, still more preferably 55,000 or less, still more preferably 50,000 or less, and even more preferably 30,000 or less. The weight average molecular weight of Component B in the present disclosure can be measured, for example, by the method described in the examples.

[0041] When Component B is Component B1, from the viewpoint of improving the polishing rate, the weight average molecular weight of Component B is preferably 800 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still more preferably 2,000 or more, preferably 3,000 or more, more preferably 5,000 or more, still more preferably 6,000 or more, still more preferably 7,000 or more. From the viewpoints of achieving both improvement in the polishing rate and storage stability, and reducing surface roughness and surface defects, it is preferably 100,000 or less, more preferably 60,000 or less, still more preferably 55,000 or less, still more preferably 50,000 or less, and still more preferably 30,000 or less.

[0042] When Component B is Component B2, from the viewpoint of improving the polishing rate, the weight average molecular weight of Component B is preferably 800 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still more preferably 2,000 or more. From the viewpoints of achieving both improvement in the polishing rate and storage stability, and reducing surface roughness and surface defects, it is preferably 100,000 or less, more preferably 50,000 or less, still more preferably 30,000 or less, still more preferably 20,000 or less, still more preferably 15,000 or less, still more preferably 12,000 or less, still more preferably 10,000 or less, still more preferably 7,000 or less, still more preferably 5,000 or less, and still more preferably 4,000 or less.

[0043] From the perspective of achieving both improved polishing rate and storage stability, the content of component B in the polishing liquid composition of the present disclosure is preferably 10 mass ppm or more, more preferably 20 mass ppm or more, still more preferably 30 mass ppm or more. From the same perspective, it is preferably 200 mass ppm or less, more preferably 150 mass ppm or less, and still more preferably 120 mass ppm or less. In the present disclosure, 1 mass% is 10,000 mass ppm (the same applies hereinafter).

[0044] From the perspective of improving storage stability, the ratio 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 0.008 or more, more preferably 0.016 or more, still more preferably 0.025 or more. From the perspective of improving the polishing rate, it is preferably 0.16 or less, more preferably 0.12 or less, and still more preferably 0.09 or less.

[0045] [Nonionic water-soluble polymer (component D)] In one or more embodiments, the polishing liquid composition of the present disclosure contains a nonionic water-soluble polymer (hereinafter also referred to as "component D") from the perspective of achieving both improved polishing rate and reduced surface roughness (haze). From the same perspective, as component D, a nonionic water-soluble polymer having an alkylene oxide group, a hydroxyl group, or an amide group in the molecule is preferred. Examples of the alkylene oxide group include an ethylene oxide group and a propylene oxide group. Component D may be of one type or a combination of two or more types.

[0046] From the perspective of achieving both improved polishing rate and reduced surface roughness (haze), component D includes at least one selected from polyglycerin, polyglycerin alkyl ether, polyglycerin alkyl ester, hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyhydroxyethyl acrylamide, polyethylene glycol having a weight average molecular weight of 300 or more and 1,000 or less, and polyalkylene glycol having a weight average molecular weight exceeding 1,000 and 50,000 or less. From the viewpoint of achieving both improved polishing rate and reduced surface roughness (haze), and from the viewpoint of suppressing foaming of the polishing liquid, the alkyl group of the polyglycerin alkyl ether preferably has 3 to 22 carbon atoms, more preferably 5 to 16 carbon atoms, and still more preferably 7 to 12 carbon atoms. The alkyl group may be a linear alkyl group or a branched alkyl group. From the viewpoint of improving wettability, the average degree of polymerization of the glycerin units of the polyglycerin alkyl ether is 5 or more, preferably 10 or more, more preferably 15 or more, still more preferably 18 or more, and from the viewpoint of achieving both improved polishing rate and reduced surface roughness (haze), it is 100 or less, preferably 60 or less, more preferably 45 or less, and still more preferably 25 or less. Examples of the polyglycerin alkyl ether include polyglycerin lauryl ether, polyglycerin decyl ether, polyglycerin myristyl ether, and the like. From the viewpoint of achieving both improved polishing rate and reduced surface roughness (haze), and from the viewpoint of suppressing foaming of the polishing liquid, the alkyl group of the polyglycerin alkyl ester preferably has 3 to 22 carbon atoms, more preferably 5 to 16 carbon atoms, and still more preferably 7 to 12 carbon atoms. The alkyl group may be a linear alkyl group or a branched alkyl group. From the viewpoint of improving wettability, the average degree of polymerization of the glycerin units of the polyglycerin alkyl ester is 5 or more, preferably 10 or more, more preferably 15 or more, still more preferably 18 or more, and from the viewpoint of achieving both improved polishing rate and reduced surface roughness (haze), it is 100 or less, preferably 60 or less, more preferably 45 or less, and still more preferably 25 or less. Examples of the polyglycerin alkyl ester include polyglycerin lauryl ester, polyglycerin decyl ester, polyglycerin myristyl ester, and the like. From the viewpoint of achieving both improved polishing rate and reduced surface roughness (haze), at least one selected from hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, and hydroxybutyl cellulose is preferred as the hydroxyalkyl cellulose, and hydroxyethyl cellulose (HEC) is more preferred. The polyalkylene glycol having a weight average molecular weight exceeding 1,000 and not exceeding 50,000 is preferably at least one selected from polyethylene glycol (PEG), polypropylene glycol (PPG), and polyalkylene glycol containing both ethylene oxide groups and propylene oxide groups (EO·PO block polymer) from the viewpoint of achieving both improvement in polishing rate and reduction in surface roughness (haze), and polyethylene glycol (PEG) is more preferred. Among these, Component D is preferably at least one selected from polyglycerin, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), hydroxyethyl cellulose (HEC), polyethylene glycol (PEG) having a weight average molecular weight of 300 or more and 1,000 or less, and polyalkylene glycol having a weight average molecular weight exceeding 1,000 and not exceeding 50,000 from the viewpoint of achieving both improvement in polishing rate and reduction in surface roughness (haze), polyglycerin, hydroxyethyl cellulose, or polyalkylene glycol having a weight average molecular weight exceeding 1,000 and not exceeding 50,000 is preferred, and polyglycerin, or polyalkylene glycol having a weight average molecular weight exceeding 1,000 and not exceeding 50,000 is more preferred.

[0047] From the viewpoint of achieving both improvement in polishing rate and reduction in surface roughness (haze), the weight average molecular weight of Component D is preferably 300 or more, preferably 500 or more, preferably 1,000 or more, more preferably 1,500 or more, still more preferably 2,000 or more, and from the same viewpoint and the viewpoint of the filterability of the polishing liquid, it is preferably less than 500,000, more preferably 400,000 or less, still more preferably 300,000 or less. The weight average molecular weight of Component D can be measured by the method described in the following examples. When Component D is polyglycerin, from the same viewpoint, the weight average molecular weight of Component D is preferably 1,000 or more, more preferably 1,500 or more, still more preferably 2,000 or more, and preferably 10,000 or less, more preferably 8,000 or less, still more preferably 6,000 or less, still more preferably 4,000 or less. When Component D is polyvinyl alcohol (PVA), from the same perspective, the weight average molecular weight of Component D is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 20,000 or more, and preferably 150,000 or less, more preferably 120,000 or less, still more preferably 100,000 or less, and still more preferably 50,000 or less. When Component D is polyvinylpyrrolidone (PVP), from the same perspective, the weight average molecular weight of Component D is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 20,000 or more, and preferably 150,000 or less, more preferably 120,000 or less, still more preferably 100,000 or less, and still more preferably 60,000 or less. When Component D is hydroxyethyl cellulose (HEC), from the same perspective, the weight average molecular weight of Component D is preferably 50,000 or more, more preferably 60,000 or more, still more preferably 70,000 or more, and preferably 500,000 or less, more preferably 400,000 or less, still more preferably 300,000 or less, still more preferably 200,000 or less, and still more preferably 100,000 or less. When Component D is polyethylene glycol (PEG) with a weight average molecular weight of 300 or more and 1,000 or less, from the same perspective, the weight average molecular weight of Component D is preferably 500 or more, and preferably 900 or less, more preferably 800 or less. When Component D is a polyalkylene glycol with a weight average molecular weight exceeding 1,000 and 50,000 or less, from the same perspective, the weight average molecular weight of Component D is preferably 1,500 or more, more preferably 3,000 or more, and preferably 30,000 or less, more preferably 15,000 or less, still more preferably 10,000 or less.

[0048] When component D contained in the polishing liquid composition of the present disclosure is PEG having a weight average molecular weight of 300 or more and 1,000 or less, component B contained in the polishing liquid composition of the present disclosure is preferably an amino group-containing water-soluble polymer having a weight average molecular weight of 800 or more and 10,000 or less. For example, when component D is polyethylene glycol (PEG) having a weight average molecular weight of 300 or more and 1,000 or less, the weight average molecular weight of component B is preferably 800 or more, more preferably 1,000 or more, still more preferably 1,500 or more, still more preferably 2,000 or more, and preferably 10,000 or less, more preferably 8,000 or less, still more preferably 5,000 or less. When component D contained in the polishing liquid composition of the present disclosure is a polyalkylene glycol having a weight average molecular weight exceeding 1,000 and 50,000 or less, component B contained in the polishing liquid composition of the present disclosure is preferably an amino group-containing water-soluble polymer having a weight average molecular weight of 2,000 or more and 100,000 or less. For example, when component D is a polyalkylene glycol having a weight average molecular weight exceeding 1,000 and 50,000 or less, the weight average molecular weight of component B is preferably 2,000 or more, more preferably 5,000 or more, still more preferably 8,000 or more, and preferably 100,000 or less, more preferably 60,000 or less, still more preferably 55,000 or less, still more preferably 50,000 or less, still more preferably 30,000 or less.

[0049] From the viewpoint of achieving both improvement in polishing rate and reduction in surface roughness (haze), the content of component D in the polishing liquid composition of the present disclosure is preferably 5 mass ppm or more, preferably 10 mass ppm or more, more preferably 30 mass ppm or more, still more preferably 35 mass ppm or more, and preferably 1,000 mass ppm or less, more preferably 500 mass ppm or less, still more preferably 300 mass ppm or less. From the same viewpoint, the content of component D in the polishing liquid composition of the present disclosure is preferably 10 mass ppm or more and 1,000 mass ppm or less, more preferably 30 mass ppm or more and 500 mass ppm or less, still more preferably 35 mass ppm or more and 300 mass ppm or less. When component D is a combination of two or more kinds, the content of component D means their total content.

[0050] In the polishing liquid composition of the present disclosure, the ratio D / A (mass ratio D / A) of the content of component D to the content of component A is preferably 0.001 or more, more preferably 0.005 or more, still more preferably 0.01 or more, still more preferably 0.015 or more, still more preferably 0.02 or more, still more preferably 0.025 or more, and preferably 1 or less, more preferably 0.7 or less, still more preferably 0.4 or less, more preferably 0.2 or less, still more preferably 0.1 or less, still more preferably 0.05 or less, from the viewpoint of achieving both improvement in polishing rate and reduction in surface roughness (haze). From the same viewpoint, the mass ratio D / A in the polishing liquid composition of the present disclosure is preferably 0.015 or more and 0.2 or less, more preferably 0.02 or more and 0.1 or less, still more preferably 0.025 or more and 0.05 or less.

[0051] [Water] In one or more embodiments, the polishing liquid composition of the present disclosure may contain water. Examples of the water include water such as ion-exchanged water and ultrapure water. The content of water in the polishing liquid composition of the present disclosure can be, for example, the remainder of components A, B, D, and optional components described later.

[0052] [Nitrogen-containing basic compound (component C)] In one or more embodiments, the polishing liquid composition of the present disclosure preferably further contains a nitrogen-containing basic compound (hereinafter also referred to as "component C") from the viewpoint of adjusting the pH. Component C is preferably a water-soluble nitrogen-containing basic compound from the viewpoints of achieving both improvement in polishing rate and storage stability, and improving surface quality. In the present disclosure, "water-soluble" means having a solubility of 0.5 g / 100 mL or more, preferably 2 g / 100 mL or more, in water (20 °C). In the present disclosure, "water-soluble nitrogen-containing basic" means a nitrogen-containing compound that exhibits basicity when dissolved in water. Component C does not include an amino group-containing water-soluble polymer (component B) in one or more embodiments. Component C may be one type or a combination of two or more types.

[0053] As component C, in one or more embodiments, at least one selected from amine compounds and ammonium compounds can be mentioned. Examples of component C include ammonia, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, 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, and combinations of one or more of these can be mentioned. Among them, from the viewpoint of achieving both improved polishing rate and storage stability, ammonia or a mixture of ammonia and hydroxyamine is preferable as component C, and ammonia is more preferable.

[0054] When the polishing liquid composition of the present disclosure contains component C, the content of component C in the polishing liquid composition of the present disclosure is preferably 5 mass ppm or more, more preferably 10 mass ppm or more, still more preferably 20 mass ppm or more, from the viewpoint of improving the polishing rate, and preferably 500 mass ppm or less, more preferably 300 mass ppm or less, still more preferably 150 mass ppm or less, still more preferably 100 mass ppm or less, from the viewpoints of improving storage stability, improving surface quality, and suppressing corrosion of the silicon substrate. From the same viewpoints, the content of component C is preferably 5 mass ppm or more and 500 mass ppm or less, more preferably 10 mass ppm or more and 300 mass ppm or less, still more preferably 20 mass ppm or more and 150 mass ppm or less, still more preferably 20 mass ppm or more and 100 mass ppm or less. When component C is a combination of two or more, the content of component C refers to their total content.

[0055] When the polishing liquid composition of the present disclosure contains component C, the ratio of the content of component C to the content of component A in the polishing liquid composition of the present disclosure, C / A (mass ratio C / A), is preferably 0.002 or more, more preferably 0.01 or more, still more preferably 0.015 or more, and still more preferably 0.025 or more from the viewpoint of improving the polishing rate. From the viewpoints of improving storage stability, improving surface quality, and suppressing corrosion of the silicon substrate, it is preferably 1 or less, more preferably 0.5 or less, still more preferably 0.1 or less, and still more preferably 0.08 or less. From the same viewpoints, the mass ratio C / 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, still more preferably 0.015 or more and 0.1 or less, and still more preferably 0.025 or more and 0.08 or less.

[0056] [Other Components] The polishing liquid composition of the present disclosure may further contain other components as long as the effects of the present disclosure are not hindered. Examples of other components include, in one or more embodiments, water-soluble polymers other than component B and component D, pH adjusters other than component C, preservatives, alcohols, chelating agents, and oxidizing agents.

[0057] [pH] The pH of the polishing liquid composition of the present disclosure is greater than 8.5, preferably 9 or more, more preferably 9.5 or more, and still more preferably 10 or more from the viewpoint of achieving both improvement in polishing rate and storage stability. From the viewpoint of improving surface quality, it is 14 or less, preferably 13 or less, more preferably 12.5 or less, still more preferably 12 or less, still more preferably 11.5 or less, and still more preferably 11 or less. From the same viewpoints, the pH of the polishing liquid composition of the present disclosure is greater than 8.5 and 14 or less, preferably 9 or more and 13 or less, more preferably 9 or more and 12.5 or less, still more preferably 9 or more and 12 or less, still more preferably 9.5 or more and 11.5 or less, still more preferably 10 or more and 11.5 or less, and still more preferably 10 or more and 11 or less. The pH of the polishing liquid composition of the present disclosure can be adjusted using component C or a known pH adjuster. In the present disclosure, the above pH is the value measured by the method described in the examples.

[0058] [pH - pKa] From the viewpoints of achieving both improvement in polishing rate and storage stability, and improvement in surface quality, the pH of the polishing liquid composition of the present disclosure is preferably greater than the pKa of Component B. From the viewpoint of achieving both improvement in polishing rate and storage stability, the difference between pH and pKa (pH - pKa) is preferably greater than 0, more preferably 0.5 or more, still more preferably 1 or more, still more preferably 1.5 or more, still more preferably 2 or more, still more preferably 2.5 or more. From the viewpoint of improving surface quality, it is preferably 7 or less, more preferably 6 or less, still more preferably 5.5 or less, still more preferably 5 or less, still more preferably 4.5 or less, still more preferably 4 or less, and still more preferably 3.5 or less.

[0059] The polishing liquid composition of the present disclosure can be produced, for example, by blending Component A, Component B, and Component D, and further, if desired, water, Component C, and other components by a known method. That is, the polishing liquid composition of the present disclosure can be produced, for example, by blending at least Component A, Component B, and Component D. Therefore, in other aspects, the present disclosure relates to a method for producing a polishing liquid composition including a step of blending at least Component A, Component B, and Component D. In the present disclosure, "blending" includes mixing Component A, Component B, Component D, and, if necessary, water, Component C, and other components simultaneously or in any order. The blending can be performed, for example, using a stirrer such as a homomixer, homogenizer, ultrasonic disperser, wet ball mill, or bead mill. The preferred blending amounts of the respective components in the method for producing the polishing liquid composition of the present disclosure described above can be the same as the preferred contents of the respective components in the polishing liquid composition of the present disclosure described above.

[0060] In the present disclosure, the "content of each component in the polishing liquid composition" refers to the content of each component at the time of use, that is, at the time when the use of the polishing liquid composition for polishing is started.

[0061] The polishing liquid composition of the present disclosure may be manufactured as a concentrate and diluted during use from the viewpoints of storage and transportation. From the viewpoints of manufacturing and transportation costs, the dilution ratio is preferably 2 times or more, more preferably 10 times or more, still more preferably 30 times or more, and even more preferably 50 times or more. From the viewpoint of storage stability, it is preferably 180 times or less, more preferably 140 times or less, still more preferably 100 times or less, and even more preferably 70 times or less. The concentrate of the polishing liquid composition of the present disclosure can be diluted with water so that the content of each component becomes the above-described content (i.e., the content during use) during use. In the present disclosure, "during use" of the concentrate of the polishing liquid composition refers to a state in which the concentrate of the polishing liquid composition is diluted.

[0062] [Polishing liquid kit] In other aspects, the present disclosure relates to a polishing liquid kit (hereinafter, also referred to as "the kit of the present disclosure") for manufacturing the polishing liquid composition of the present disclosure. According to the kit of the present disclosure, a polishing liquid composition capable of achieving an improvement in polishing rate, a reduction in surface roughness (haze), and storage stability of the concentrate can be obtained. Examples of the kit of the present disclosure include a polishing liquid kit containing a solution containing component A, component B, and component D in one or more embodiments. The solution may contain the other components described above as necessary. The solution may be diluted with water as necessary during use.

[0063] [Method for polishing a silicon substrate] In other aspects, the present disclosure relates to a method for polishing a silicon substrate (hereinafter, also referred to as "the polishing method of the present disclosure") including 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"). According to the polishing method of the present disclosure, since the polishing liquid composition of the present disclosure is used, both an improvement in polishing rate and an improvement in surface quality can be achieved.

[0064] In the polishing process of the polishing method of the present disclosure, for example, the silicon substrate to be polished can be pressed against a surface plate with a polishing pad attached, and the silicon substrate to be polished 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 surface plate applied to the surface to be polished of the silicon substrate to be polished during polishing.

[0065] In the polishing process of the polishing method of the present disclosure, for example, the silicon substrate to be polished can be pressed against a surface plate with a polishing pad 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 or higher and 40°C or lower. From the perspective of achieving both improvement in polishing rate and surface quality such as reduction in surface roughness (haze), a temperature of 15°C or higher or 20°C or higher is preferable for the temperature of the polishing liquid composition and the surface temperature of the polishing pad, and a temperature of 40°C or lower or 30°C or lower is preferable.

[0066] [Method for manufacturing a semiconductor substrate] In other aspects, the present disclosure relates to a method for manufacturing a semiconductor substrate (hereinafter also referred to as "the method for manufacturing a semiconductor substrate of the present disclosure"), including 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 method for manufacturing a semiconductor substrate of the present disclosure, by using the polishing liquid composition of the present disclosure, it is possible to achieve both an improvement in polishing rate and a reduction in surface roughness (haze), so that a high-quality semiconductor substrate can be manufactured with high yield, high productivity, and low cost.

[0067] The polishing step in the method for manufacturing a semiconductor substrate of the present disclosure can include, for example, a lapping (rough polishing) step of planarizing a single-crystalline silicon substrate obtained by slicing a single-crystalline silicon ingot into a thin disk shape, and a finish polishing step of mirror-finishing the surface of the single-crystalline silicon substrate after etching the lapped single-crystalline silicon substrate. From the perspective of achieving both an improvement in polishing rate and an improvement in surface quality, it is more preferable to use the polishing liquid composition of the present disclosure in the above finish polishing step.

[0068] In the polishing process of the semiconductor substrate manufacturing method of the present disclosure, for example, a substrate having a polysilicon film formed by chemical vapor deposition (CVD) on a silicon substrate having a silicon dioxide film and a silicon nitride film is flattened by removing the unevenness of the polysilicon film, and a step of simultaneously polishing and flattening the underlying silicon dioxide film, silicon nitride film, and polysilicon film can be included. From the viewpoint of achieving both an improvement in polishing rate and an improvement in surface quality, the polishing liquid composition of the present disclosure is more preferably used in the step of removing and flattening the unevenness of the polysilicon film.

[0069] In the polishing process of the semiconductor substrate manufacturing method of the present disclosure, polishing can be performed under the same conditions (such as polishing pressure, polishing liquid composition, and surface temperature of the polishing pad) as those in the polishing process of the polishing method of the present disclosure described above.

[0070] In one or more embodiments, the semiconductor substrate manufacturing method of the present disclosure may include a dilution step of diluting a concentrate of the polishing liquid composition of the present disclosure before the polishing step. For example, water can be used as the diluent.

[0071] In the cleaning step of the semiconductor substrate manufacturing method of the present disclosure, from the viewpoint of reducing residues on the surface of the silicon substrate, it is preferable to perform inorganic cleaning. Examples of the cleaning agent used for inorganic cleaning include an inorganic cleaning agent containing at least one selected from hydrogen peroxide, ammonia, hydrochloric acid, sulfuric acid, hydrofluoric acid, and ozone water.

[0072] In one or more embodiments, the semiconductor substrate manufacturing method of the present disclosure may further include a step of rinsing the cleaned silicon substrate with water and drying it after the cleaning step.

Example

[0073] Hereinafter, the present disclosure will be described in more detail with reference to examples, but these are exemplary and the present disclosure is not limited to these examples.

[0074] 1. Preparation of polishing liquid composition (Concentrate of polishing liquid composition) The silica particles shown in Table 1 (Component A), the amino group-containing water-soluble polymer shown in Table 1 (Component B or non-Component B), ammonia (Component C), the nonionic water-soluble polymer shown in Table 1 (Component D), and ultrapure water were stirred and mixed to obtain a concentrate (60-fold) of the polishing liquid composition. The pH of the concentrate at 25°C was 10.6 to 11.0. (Polishing liquid composition) The above concentrate was diluted 60-fold with ion-exchanged water to obtain the polishing liquid compositions of Examples 1 to 22 and Comparative Examples 1 to 3. The content of each component in Table 1 is the content of each component (mass% or mass ppm, active ingredient) at the time of use of the diluted polishing liquid composition. The content of ultrapure water is the remainder excluding Component A, Component B or non-Component B, Component C, and Component D. The pH of each polishing liquid composition (at the time of use) at 25°C was 10.3. The pH at 25°C is the value measured using a pH meter (Toa Denpa Kogyo Co., Ltd., HM-30G), and is the value after 1 minute of immersing the electrode of the pH meter in the polishing liquid composition or its concentrate.

[0075] The following were used for Component A, Component B, non-Component B, Component C, and Component D used in the preparation of each polishing liquid composition. (Component A) Colloidal silica [average primary particle diameter 25 nm, average secondary particle diameter 49 nm, degree of aggregation 2.0] (Component B) B1: Methyl diallylamine-sulfur dioxide copolymer [manufactured by Nitto Boehringer Medical Co., Ltd., weight average molecular weight 3,000] B2: Glycidol-modified polyallylamine (modification rate 2.0) [manufactured by Nitto Boehringer Medical Co., Ltd., weight average molecular weight 11,000] B3: Glycidol-modified polyallylamine (modification rate 1.8) [manufactured by Nitto Boehringer Medical Co., Ltd., weight average molecular weight 10,200] B4: Glycidol-modified polyallylamine (modification rate 1.5) [manufactured by Nitto Boehringer Medical Co., Ltd., weight average molecular weight 8,900] B5: Glycidol-modified polyallylamine (modification rate 1.0) [manufactured by Nitto Boehringer Medical Co., Ltd., weight average molecular weight 6,900] B8: Glycidol-modified polyallylamine (modification rate 1.5) [manufactured by Nitto Boehringer Medical Co., Ltd., weight-average molecular weight 17,000] B9: Glycidol-modified polyallylamine (modification rate 1.5) [manufactured by Nitto Boehringer Medical Co., Ltd., weight-average molecular weight 26,000] B10: Glycidol-modified polyallylamine (modification rate 2.0) [manufactured by Nitto Boehringer Medical Co., Ltd., weight-average molecular weight 55,000] (Non-component B) B6: Allylamine (free) polymer [Nitto Boehringer Medical PAA-03, weight-average molecular weight 3,000] B7: Polyethyleneimine [manufactured by Nippon Shokubai Co., Ltd., SP-200, weight-average molecular weight 10,000] (Component C) Ammonia [28 mass% aqueous ammonia, manufactured by Kishida Chemical Co., Ltd., reagent grade] (Component D) D1: Polyglycerin [“XPW” manufactured by Daicel Corporation, degree of polymerization 40, weight-average molecular weight 2,980] D2: HEC (Hydroxyethyl cellulose) [manufactured by Hercules Inc., NATROSOL 250L-Pharm, weight-average molecular weight 90,000] D3: PVA (Polyvinyl alcohol) [manufactured by Kuraray Co., Ltd., PVA105, degree of polymerization: 500, weight-average molecular weight 25,000] D4: PVP (Polyvinylpyrrolidone) [manufactured by Nippon Shokubai Co., Ltd., PVP K-30, weight-average molecular weight 40,000] D5: PEG (Polyethylene glycol) [manufactured by NOF Corporation, PEG#400, weight-average molecular weight 400] D6: PEG (Polyethylene glycol) [manufactured by NOF Corporation, PEG#600, weight-average molecular weight 600] D7: HEC (Hydroxyethyl cellulose) [manufactured by Daicel Corporation, SE400, weight-average molecular weight 250,000] D8: PEG (Polyethylene glycol) [manufactured by NOF Corporation, PEG#1000, weight-average molecular weight 1,000] D9: PEG (Polyethylene glycol) [manufactured by NOF Corporation, PEG#2000, weight-average molecular weight 2,000] D10: PEG (Polyethylene Glycol) [manufactured by NOF Corporation, PEG#6000, weight-average molecular weight 6,000] D11: PEG (Polyethylene Glycol) [manufactured by NOF Corporation, PEG#20000, weight-average molecular weight 20,000] D12: EO·PO block polymer [manufactured by ADEKA Corporation, Pluronic F-68, weight-average molecular weight 9000]

[0076] 2. Measurement methods of various parameters (1) Measurement of the average primary particle diameter of silica particles (Component A) The average primary particle diameter (nm) of Component A was calculated by the following formula using the specific surface area S (m 2 / g) calculated by the BET (nitrogen adsorption) method. Average primary particle diameter (nm) = 2727 / S

[0077] The specific surface area S of Component A was measured by the nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritics automatic specific surface area measuring device "FlowSorb III 2305", manufactured by Shimadzu Corporation) after performing the following [Pretreatment], accurately weighing approximately 0.1 g of the measurement sample to four decimal places in the measurement cell, and drying it in an atmosphere of 110°C for 30 minutes immediately before the specific surface area measurement. [Pretreatment] (a) Adjust the slurry-like Component A to pH 2.5 ± 0.1 with an aqueous nitric acid solution. (b) Take the slurry-like Component A adjusted to pH 2.5 ± 0.1 in a petri dish and dry it in a hot air dryer at 150°C for 1 hour. (c) After drying, finely pulverize the obtained sample in an agate mortar. (d) Suspend the pulverized sample in ion-exchanged water at 40°C and filter it through a membrane filter with a pore size of 1 μm. (e) Wash the filtrate on the filter 5 times with 20 g of ion-exchanged water (40°C). (f) Take the filter with the filtrate attached in a petri dish and dry it in an atmosphere of 110°C for 4 hours. (g) Take the dried filtrate (Component A) so that no filter debris is mixed in, and finely pulverize it in a mortar to obtain a measurement sample.

[0078] (2) Average secondary particle diameter of silica particles (Component A) The average secondary particle diameter (nm) of Component A was measured using the dynamic light scattering method (apparatus name: "Zetasizer Nano ZS", manufactured by Sysmex Corporation) after adding the abrasive to ion-exchanged water so that the concentration of Component A became 0.25% by mass, and then filling the obtained aqueous dispersion into a Disposable Sizing Cuvette (10 mm cell made of polystyrene) up to a height of 10 mm from the bottom.

[0079] (3) Measurement of weight-average molecular weight of water-soluble polymer The weight-average molecular weight of the water-soluble polymer (Component B, non-Component B, Component D) was calculated based on the peak in the chromatogram obtained by applying the gel permeation chromatography (GPC) method under the following conditions. <Amino group-containing water-soluble polymer (Component B or non-Component B)> Apparatus: HLC-8320 GPC (manufactured by Tosoh Corporation, detector-integrated type) Column: α-M + α-M Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Flow rate: 1.0 mL / min Column temperature: 40 °C Detector: Shodex RI SE-61 differential refractive index detector Standard substance: Monodisperse polyethylene glycol with known molecular weight <Nonionic water-soluble polymer (Component D)> Apparatus: HLC-8320 GPC (manufactured by Tosoh Corporation, detector-integrated type) Column: GMPWXL + GMPWXL (anion) Eluent: 0.2 M phosphate buffer / CH3CN = 9 / 1 Flow rate: 0.5 mL / min Column temperature: 40 °C Detector: Shodex RI SE-61 differential refractive index detector Standard substance: Monodisperse polyethylene glycol with known molecular weight

[0080] (4) Measurement of pKa Using an HM-41K type pH meter (manufactured by Toa DKK Corporation), an aqueous solution of Component B adjusted to 1 M was subjected to potentiometric titration with 0.1 M hydrochloric acid at room temperature. The pKa was calculated from the obtained titration curve.

[0081] (5) Glycidol modification rate The glycidol modification rate was 13 determined using 13C-NMR. <Measurement conditions> Sample: 200 mg of glycidol-modified polyallylamine was dissolved in 0.6 mL of heavy water Apparatus used: 400 MHz 13 13C-NMR (Agilent 400-MR DD2 manufactured by Agilent Technologies, Inc.) Measurement conditions: 13 13C-NMR measurement, pulse interval time 5 seconds, tetramethylsilane as the standard peak (σ: 0.0 ppm) for measurement Number of integrations: 5000 times Each peak range used for integration: A: 71.0 to 72.3 ppm (integration value of the peak of C to which the secondary hydroxyl group of glycidol reacted with the amino group is bonded) B: 32.0 to 41.0 ppm (integration value of the peak of the main chain C of allylamine) <Glycidol modification rate> The glycidol modification rate (equivalent ratio of glycidol to the equivalent of amino groups) is determined by the following formula. Glycidol modification rate (equivalent ratio) = 2A / B

[0082] 3. Evaluation of the polishing liquid compositions of Examples 1 to 22 and Comparative Examples 1 to 3 (1) Polishing method, etc. For each polishing liquid composition, filtration was performed immediately before polishing using a filter (compact cartridge filter "MCP-LX-C10S", manufactured by Advantec), and finish polishing and cleaning were performed on the following silicon substrate to be polished under the following polishing conditions. <Silicon substrate to be polished> Single crystal silicon substrate [silicon single-sided mirror surface substrate with a diameter of 200 mm, conductivity type: P, crystal orientation: 100, resistivity: 0.1 Ω·cm or more and less than 100 Ω·cm] The above single-crystal silicon substrate was preliminarily coarsely polished using a commercially available polishing liquid composition (manufactured by Fujimi Incorporated, GLANZOX 1302). The haze of the single-crystal silicon substrate after the completion of the coarse polishing and before being subjected to the finish polishing was 2 to 3 ppm.

[0083] <Finish polishing conditions> Polishing machine: Single-sided 8-inch polishing machine "GRIND-X SPP600s" (manufactured by Okamoto Works) Polishing pad: Suede pad (manufactured by Toray Coating Co., Ltd., Asker hardness: 64, thickness: 1.37 mm, nap length: 450 μm, aperture diameter: 60 μm) Polishing pressure of silicon substrate: 100 g / cm 2 Platen rotation speed: 60 rpm Polishing time: 5 minutes Supply rate of polishing liquid composition: 150 g / min Temperature of polishing liquid composition: 23 °C Carrier rotation speed: 62 rpm

[0084] <Measurement of surface roughness (haze) of silicon substrate> The value (DWO haze) in the dark field wide oblique incidence channel (DWO) measured using a surface roughness measuring device "Surfscan SP1-DLS" (manufactured by KLA Tencor) was used.

[0085] <Washing method> After the finish polishing, the silicon substrate was subjected to ozone cleaning and dilute hydrofluoric acid cleaning as follows. In the ozone cleaning, an aqueous solution containing 20 ppm of ozone was sprayed from a nozzle toward the center of the silicon substrate rotating at 600 rpm with a flow rate of 1 L / min for 3 minutes. At this time, the temperature of the ozone water was set to room temperature. Next, the dilute hydrofluoric acid cleaning was performed. In the dilute hydrofluoric acid cleaning, an aqueous solution containing 0.5 mass% of ammonium hydrogen fluoride (special grade, Nacalai Tesque, Inc.) was sprayed from a nozzle toward the center of the silicon substrate rotating at 600 rpm with a flow rate of 1 L / min for 6 seconds. The above ozone cleaning and dilute hydrofluoric acid cleaning were performed in a set of two sets, and finally spin drying was performed. In the spin drying, the silicon substrate was rotated at 1,500 rpm.

[0086] (2) Evaluation of polishing rate The weights of each silicon substrate before and after polishing were measured using an analytical balance (Sartorius "BP-210S"), and the obtained weight difference was divided by the density, area, and polishing time of the silicon substrate to obtain the single-sided polishing rate per unit time. The results are shown in Table 1. Note that the weight of the silicon substrate after polishing is the weight of the silicon substrate after the above-mentioned finish polishing and cleaning.

[0087] (3) Evaluation of storage stability of the concentrate 100 g of the concentrate of each polishing liquid composition was put into a 100 ml screw tube and sealed, and the storage stability after 1 day was evaluated according to the following evaluation criteria. The concentrate of the polishing liquid composition was stored in a room at 23°C. The results are shown in Table 1. <Evaluation criteria> A: After 1 day has passed since the preparation of the concentrate of the polishing liquid composition, no aggregation or separation occurs, and the dispersion stability is maintained. B: After 1 day has passed since the preparation of the concentrate of the polishing liquid composition, slight aggregation and separation occur. C: After 1 day has passed since the preparation of the concentrate of the polishing liquid composition, aggregation and separation occur.

[0088]

Table 1

[0089] As shown in Table 1, it was found that the polishing liquid compositions of Examples 1 to 22 can achieve an improvement in polishing rate, a reduction in the surface roughness (haze) of the silicon substrate, and storage stability of the concentrate compared to the polishing liquid compositions of Comparative Examples 1 to 3.

Industrial applicability

[0090] By using the polishing liquid composition of the present disclosure, an improvement in polishing rate, a reduction in the surface roughness (haze) of the silicon substrate, and storage stability can be achieved. Therefore, the polishing liquid composition of the present disclosure is particularly useful as a polishing liquid composition used in the manufacturing process of silicon substrates.

Claims

1. A polishing liquid composition for a silicon substrate, comprising the following component A, the following component B, and the following component D, and having a pH greater than 8.5 and less than or equal to 14. Component A: silica particles Component B: an amino group-containing water-soluble polymer containing a structural unit derived from at least one monomer selected from allylamine and diallylamine and having a pKa of 5 or more and 8.5 or less Component D: a nonionic water-soluble polymer

2. The polishing liquid composition according to claim 1, wherein at least a part of the amino groups in the structural unit derived from allylamine has a steric shielding group.

3. The polishing liquid composition according to claim 1 or 2, wherein at least a part of the amino groups in the structural unit derived from allylamine is a secondary amino group or a tertiary amino group containing a hydrocarbon group having 3 to 11 carbon atoms and having a hydroxyl group.

4. The polishing liquid composition according to any one of claims 1 to 3, wherein component B is a reaction product of polyallylamine and a glycide derivative.

5. The polishing liquid composition according to claim 1, wherein at least a part of the amino groups in the structural unit derived from diallylamine has an electron-withdrawing group at the β-position or γ-position.

6. The polishing liquid composition according to claim 1 or 5, wherein component B is a compound containing a structural unit represented by the following formula (III). 【Chemical 1】 In formula (III), R 3 is an alkyl group having 1 to 3 carbon atoms which may have a hydroxyl group, and n + m = 1.

7. The polishing liquid composition according to any one of claims 1 to 6, wherein component D is a water-soluble polymer having an alkylene oxide group, a hydroxyl group, or an amide group in the molecule.

8. Component D is at least one selected from polyglycerin, polyglycerin alkyl ether, polyglycerin alkyl ester, hydroxyalkyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyhydroxyethyl acrylamide, polyethylene glycol having a weight average molecular weight of 300 or more and 1,000 or less, and polyalkylene glycol having a weight average molecular weight exceeding 1,000 and 50,000 or less. The polishing liquid composition according to any one of claims 1 to 7.

9. A method for polishing a silicon substrate, comprising a step of polishing a silicon substrate to be polished using the polishing liquid composition according to any one of claims 1 to 8.

10. A step of polishing a silicon substrate to be polished using the polishing liquid composition according to any one of claims 1 to 8; A method for manufacturing a semiconductor substrate, comprising a step of cleaning the polished silicon substrate.

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