Wetting agent

Abstract

In one embodiment, a wetting agent is provided that can improve the wettability of a silicon wafer surface and improve the polishing speed when used for polishing a silicon wafer. [Solution] In one embodiment, this disclosure relates to a wetting agent containing a polyamine-N-oxide having a structure derived from one polyamine selected from polyethyleneimine, polyallylamine, and polydiallylamine, and a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds.

Description

[Technical Field]

[0001] This disclosure relates to a wetting agent, a silicon wafer polishing solution containing the wetting agent, and a method for manufacturing a semiconductor device, which includes a step of polishing a silicon wafer using the silicon wafer polishing solution. [Background technology]

[0002] In recent years, with the increasing demand for higher recording capacity in semiconductor memory, silicon wafers used to manufacture semiconductor memory are required to have not only high flatness but also reduced surface defects.

[0003] Therefore, in order to reduce residues on the silicon wafer surface, which are one of the surface defects, various wetting agents have been developed for silicon wafer polishing with the aim of improving the wettability (hydrophilization) of the silicon wafer surface.

[0004] As a specific example of a wetting agent, for instance, Patent Document 1 discloses that surface defects in silicon wafers can be reduced using hydroxyethyl cellulose (HEC). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] WO2015 / 098777 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, there has been a strong demand for reducing surface defects in silicon wafers due to the increasing integration density of semiconductor memory, and for improving the productivity of silicon wafers due to the rising demand for semiconductor memory. However, the technologies described above have been insufficient in improving wettability and polishing speed, which contribute to the reduction of surface defects.

[0007] Therefore, this disclosure relates to a wetting agent that can improve the wettability of a silicon wafer surface and improve the polishing speed when used for polishing a silicon wafer, a silicon wafer polishing solution containing the wetting agent, and a method for manufacturing a semiconductor device that includes a step of polishing a silicon wafer using the silicon wafer polishing solution. [Means for solving the problem]

[0008] This disclosure relates, in one embodiment, to a wetting agent containing a polyamine-N-oxide having a structure derived from one polyamine selected from polyethyleneimine, polyallylamine, and polydiallylamine, and a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds.

[0009] This disclosure relates, in one embodiment, to a silicon wafer polishing solution containing the wetting agent of this disclosure.

[0010] This disclosure relates, in one embodiment, to a method for manufacturing a semiconductor device, which includes a step of polishing a silicon wafer using the silicon wafer polishing solution of this disclosure. [Effects of the Invention]

[0011] The wetting agent of this disclosure can improve the wettability of the silicon wafer surface and improve the polishing speed when used for polishing silicon wafers. [Modes for carrying out the invention]

[0012] [Wetting agent] This disclosure is based on the finding that the wettability of a silicon wafer surface can be improved and the silicon wafer can be made hydrophilic by using a wetting agent containing a specific polyamine-N-oxide. Furthermore, it is based on the finding that when the wetting agent is used for silicon wafer polishing, the polishing speed can be improved without the use of abrasive particles.

[0013] In other words, in one embodiment, this disclosure relates to a wetting agent (hereinafter also referred to as "the wetting agent of this disclosure") that contains a polyamine-N-oxide having a structure derived from one polyamine selected from polyethyleneimine, polyallylamine, and polydiallylamine, and a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds.

[0014] The wetting agent of this disclosure can improve the wettability of the silicon wafer surface. Furthermore, when used for silicon wafer polishing, it can improve the polishing speed.

[0015] Although the detailed mechanism of action of the wetting agent described herein is not clear, it is presumed to be as follows. The wetting agent of this disclosure contains a polyamine-N-oxide having a structure derived from one selected polyamine and a structure derived from one or more selected glycidyl group-containing compounds and acrylamide compounds. Because the polyamine-N-oxide has a polyamine-derived structure, it contains a large number of nitrogen atoms in its molecule. Furthermore, at least some of these nitrogen atoms have an N-oxide structure, thus possessing high polarity while having zero charge. Thus, because the polyamine-N-oxide has high polarity in many molecules but no charge within the molecule, it does not experience the rigidification of the polymer chain due to repulsion between charged groups, which can occur in charged polymer compounds. Furthermore, because the polyamine-N-oxide contained in the wetting agent of this disclosure has a structure derived from one or more selected glycidyl group-containing compounds and acrylamide compounds, it exhibits high polarity similar to the N-oxide structure, further enhancing the polarity of the N-oxide structure. Therefore, when the wetting agent of this disclosure comes into contact with a silicon wafer, the polyamine-N-oxide has a suitable affinity for the semimetallic silicon atoms and its adsorption sites are densely located, resulting in high adsorption to the silicon wafer. Due to its high polarity, it can improve the wettability of the silicon wafer surface where adsorption has occurred, thereby promoting hydrophilization of the silicon wafer. Furthermore, it is believed that the polishing speed can be improved when the wetting agent of this disclosure is used for polishing silicon wafers. However, the present disclosure may not be construed as being limited to these mechanisms.

[0016] (Polyamine-N-oxide) The polyamine-N-oxide contained in the wetting agent of the present disclosure has a structure derived from one kind of polyamine selected from polyethyleneimine, polyallylamine, and polydiallylamine (hereinafter also referred to as "the polyamine of the present disclosure"), and a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds. And at least a part of the nitrogen atoms contained in the structure derived from the polyamine of the present disclosure has an N-oxide structure. That is, the polyamine-N-oxide contained in the wetting agent of the present disclosure has a structure derived from the polyamine of the present disclosure and a structure derived from one or more selected from glycidyl group-containing compounds and acrylamide compounds, and at least a part of the nitrogen atoms contained in the polyamine of the present disclosure has an N-oxide structure, which is a water-soluble polymer. Hereinafter, the water-soluble polymer contained in the wetting agent of the present disclosure is also referred to as "the polyamine-N-oxide of the present disclosure". The polyamine-N-oxide of the present disclosure may be one kind or a combination of two or more kinds. The polyamine of the present disclosure is preferably at least one selected from a polyethyleneimine homopolymer obtained by polymerizing ethyleneimine as a monomer, a polyallylamine homopolymer obtained by polymerizing allylamine as a monomer, and a polydiallylamine homopolymer obtained by polymerizing diallylamine as a monomer. The preferred weight average molecular weight of the polyamine of the present disclosure, that is, the weight average molecular weight of the structure derived from the polyamine of the present disclosure in the polyamine-N-oxide of the present disclosure, is preferably 2,000 or more, more preferably 5,000 or more, still more preferably 10,000 or more, and even more preferably 15,000 or more from the viewpoint of enhancing the wettability of the obtained polyamine-N-oxide of the present disclosure and increasing the polishing rate. From the same viewpoint, it is preferably 200,000 or less, more preferably 150,000 or less, still more preferably 100,000 or less, and even more preferably 80,000 or less. When the polyamine-derived structure of the polyamine-N-oxide of the present disclosure is derived from polyethyleneimine, the weight-average molecular weight of the polyethyleneimine-derived structure is preferably 2,000 or more, more preferably 5,000 or more, still more preferably 10,000 or more, and even more preferably 15,000 or more from the viewpoint of enhancing the wettability of the obtained polyamine-N-oxide of the present disclosure and also enhancing the polishing rate. From the same viewpoint, it is preferably 200,000 or less, more preferably 150,000 or less, still more preferably 100,000 or less, and even more preferably 80,000 or less. When the polyamine-derived structure of the polyamine-N-oxide of the present disclosure is derived from polyallylamine or polydiallylamine, the weight-average molecular weight of the polyallylamine- or polydiallylamine-derived structure is preferably 2,000 or more, more preferably 5,000 or more from the viewpoint of enhancing the wettability of the obtained polyamine-N-oxide of the present disclosure and also enhancing the polishing rate. From the same viewpoint, it is preferably 200,000 or less, more preferably 100,000 or less, still more preferably 50,000 or less, and even more preferably 10,000 or less. 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).

[0017] The polyamine-N-oxide of the present disclosure has a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds. In one or more embodiments, the structure derived from the glycidyl group-containing compound preferably has a bond between the nitrogen atom contained in the polyamine of the present disclosure and the carbon atom to which the oxygen atom of the epoxy group in the glycidyl group is bonded. In one or more embodiments, the structure derived from the acrylamide compound preferably has a bond between the same nitrogen atom and the carbon atom at the β-position with respect to the carbonyl group of the amide group of the acrylamide compound.

[0018] Specific examples of glycidyl group-containing compounds that generate a structure derived from a glycidyl group-containing compound in the polyamine-N-oxide of this disclosure include at least one selected from alkylglycidyl ethers, arylglycidyl ethers, alkylarylglycidyl ethers, and glycidol. Preferred examples of alkylglycidyl ethers include alkylglycidyl ethers having 1 to 8 carbon atoms, of which one or more selected from methylglycidyl ether, ethylglycidyl ether, and butylglycidyl ether are more preferred. Phenylglycidyl ether is a preferred example of an arylglycidyl ether. One or more selected from benzylglycidyl ether, isopropylphenylglycidyl ether, and butylphenylglycidyl ether are preferred examples of alkylaryl ethers. Among these, glycidol is more preferred from the viewpoint of improving the wettability of the wetting agent of this disclosure and from the viewpoint of improving the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers. In other words, if the polyamine-N-oxide of this disclosure has a structure derived from a glycidyl group-containing compound, in one or more embodiments, it is preferable that the structure derived from the glycidyl group-containing compound is a structure derived from glycidol. The structures derived from glycidyl group-containing compounds in this disclosure can be obtained in one or more embodiments by reacting a polyamine of this disclosure with a glycidyl group-containing compound. The ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that react with the glycidyl group-containing compound (reaction rate of nitrogen atoms) is preferably 50% or more, more preferably 60% or more, even more preferably 80% or more, even more preferably 90% or more, and even more preferably 100% or more, from the viewpoint of improving the wettability of the wetting agent of this disclosure and improving the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers. In this disclosure, the ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that react with the glycidyl group-containing compound (the reaction rate of nitrogen atoms) is: 13The ratio (mol%) of primary, secondary, and tertiary nitrogen atoms in the polyamine-derived structure of this disclosure, calculated by 13C-NMR measurement, is an estimated value obtained from the change before and after reaction with a glycidyl group-containing compound. Specifically, the amount of carbon atoms adjacent to tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polyamine-derived structure of this disclosure is measured. 13 The ratios of tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polyamine-derived structure of this disclosure are determined by 13C-NMR. Similarly, the ratios of tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polymer compound obtained by reacting the polyamine-derived structure of this disclosure with a glycidyl group-containing compound are determined. The sum of the difference between the ratio of tertiary nitrogen atoms in the polymer compound obtained by reacting the polyamine-derived structure of this disclosure and the ratio of tertiary nitrogen atoms in the polyamine-derived structure of this disclosure (increase in the ratio of tertiary nitrogen atoms), and the difference between the ratio of secondary nitrogen atoms in the polyamine-derived structure of this disclosure and the ratio of secondary nitrogen atoms in the polymer compound obtained by reacting the polyamine-derived structure of this disclosure with a glycidyl group-containing compound (decrease in the ratio of secondary nitrogen atoms), is defined as the ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that reacted with the glycidyl group-containing compound. Furthermore, in this disclosure, since there are tertiary nitrogen atoms and secondary nitrogen atoms that are bonded to both a glycidyl group-containing compound and a group derived from the polyamine skeleton of this disclosure, the reaction ratio may exceed 100%.

[0019] In the polyamine-N-oxides of this disclosure, specific examples of compounds that generate structures derived from acrylamide compounds include at least one selected from acrylamide, N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, and N,N-diisopropylacrylamide. Among these, at least one selected from N,N-dimethylacrylamide and N,N-diethylacrylamide is more preferred, and N,N-dimethylacrylamide is even more preferred, from the viewpoint of improving the wettability of the wetting agent of this disclosure and increasing the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers. In other words, when the polyamine-N-oxide of this disclosure has a structure derived from an acrylamide compound, in one or more embodiments, the structure derived from the acrylamide compound is preferably at least one selected from a structure derived from N,N-dimethylacrylamide and a structure derived from N,N-diethylacrylamide, and more preferably has a structure derived from N,N-dimethylacrylamide. The structures derived from acrylamide compounds in this disclosure can be obtained in one or more embodiments by reacting a polyamine of this disclosure with an acrylamide compound. The ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that react with the acrylamide compound (reaction rate of nitrogen atoms) is preferably 50% or more, more preferably 60% or more, even more preferably 80% or more, even more preferably 90% or more, and even more preferably 100% or more. In this disclosure, the ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that react with the acrylamide compound (the reaction rate of nitrogen atoms) is: 13 The ratio (mol%) of primary, secondary, and tertiary nitrogen atoms in the polyamine-derived structure of this disclosure, calculated by 13C-NMR measurement, is an estimated value based on the change before and after reaction with the acrylamide compound. Specifically, the amount of carbon atoms adjacent to tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polyamine-derived structure of this disclosure, as measured by the NMR, is determined. 13The ratios of tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polyamine-derived structure of this disclosure are determined by 13C-NMR. Similarly, the ratios of tertiary nitrogen atoms, secondary nitrogen atoms, and primary nitrogen atoms in the polymer compound after reacting the polyamine-derived structure of this disclosure with the acrylamide compound are determined. The sum of the difference between the ratio of tertiary nitrogen atoms in the polymer compound after reacting the polyamine-derived structure of this disclosure and the ratio of tertiary nitrogen atoms in the polyamine-derived structure of this disclosure (increase in the ratio of tertiary nitrogen atoms), and the difference between the ratio of secondary nitrogen atoms in the polyamine-derived structure of this disclosure and the ratio of secondary nitrogen atoms in the polymer compound after reacting the polyamine-derived structure of this disclosure with the acrylamide compound (decrease in the ratio of secondary nitrogen atoms), is defined as the ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that reacted with the acrylamide compound. Furthermore, in this disclosure, since there are tertiary nitrogen atoms and secondary nitrogen atoms that are bonded to both the acrylamide compound and the polyamine skeleton of this disclosure, the reaction ratio may exceed 100%.

[0020] In one or more embodiments, the polyamine-N-oxides of this disclosure can be obtained by N-oxidizing a nitrogen atom in a polyamine to which a glycidyl group-containing compound and / or an acrylamide compound has been added, using an oxidizing agent such as hydrogen peroxide.

[0021] In the polyamine-N-oxides of this disclosure, the proportion of nitrogen atoms in the structure derived from the polyamine of this disclosure that are in an N-oxide structure (hereinafter also referred to as the "ratio of N-oxide structures in nitrogen atoms of the polyamine-N-oxides of this disclosure") is preferably 10% or more, more preferably 25% or more, even more preferably 50% or more, even more preferably 55% or more, even more preferably 90% or more, even more preferably 98% or more, even more preferably 99% or more, and even more preferably 100%, from the viewpoint of improving the wettability of the wetting agent of this disclosure and improving the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers. In this disclosure, the ratio of N-oxide structures in nitrogen atoms of the polyamine-N-oxides of this disclosure is determined by the method using the total amine value described in the examples.

[0022] From the viewpoint of improving the wettability of the wetting agent of this disclosure and increasing the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers, it is preferable that the polyamine-N-oxide of this disclosure has one or more structures selected from any of the following formulas (I) to (VI). [ka] In the above equations (I) to (VI), R 1 , R 2 Each of these independently represents either a hydrogen atom, an alkyl group, an aryl group, or an alkylaryl group.

[0023] In the above equations (I) to (VI), R 1 From the viewpoint of further improving the wettability of the wetting agent of this disclosure, and from the viewpoint of further increasing the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers, it is more preferable that R be a hydrogen atom. 2 From the viewpoint of further improving the wettability of the wetting agent of this disclosure and from the viewpoint of further increasing the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers, it is more preferable that the group be a methyl group.

[0024] In one or more embodiments, the polyamine-N-oxide of the present disclosure is preferably one or more selected from the following polymers (1) to (3), from the viewpoint of improving the wettability of the wetting agent of the present disclosure and increasing the polishing speed when the wetting agent of the present disclosure is used as a polishing solution for silicon wafers. Polymer (1): A glycidol adduct of polyethyleneimine, wherein at least some of the nitrogen atoms of the amino group of the glycidol adduct of polyethyleneimine are N-oxideized. Polymer (2): An N,N-dimethylacrylamide adduct of polyethyleneimine, wherein at least some of the nitrogen atoms of the amino group of the N,N-dimethylacrylamide adduct of polyethyleneimine are N-oxideized. Polymer (3): A glycidol adduct of polyallylamine, in which at least a part of the nitrogen atoms of the amino groups of the glycidol adduct of the polyallylamine is N-oxidized

[0025] Polymer (1) is, in one or more embodiments, a polymer having a structure derived from polyethyleneimine and a structure derived from glycidol, and at least a part of the nitrogen atoms contained in the structure derived from polyethyleneimine has an N-oxide structure, having at least one of the structures represented by the formula (I) and the structure represented by the formula (II), and R 1 is a hydrogen atom. Polymer (2) is, in one or more embodiments, a polymer having a structure derived from polyethyleneimine and a structure derived from N,N-dimethylacrylamide, and at least a part of the nitrogen atoms contained in the structure derived from polyethyleneimine has an N-oxide structure, having at least one of the structures represented by the formula (III) and the structure represented by the formula (IV), and R 2 is a methyl group. Polymer (3) is, in one or more embodiments, a polymer having a structure derived from polyallylamine and a structure derived from glycidol, and at least a part of the nitrogen atoms contained in the structure derived from polyallylamine has an N-oxide structure, having the structure represented by the formula (V), and R 1 is a hydrogen atom.

[0026] In one or more embodiments, the polyamine-N-oxide of the present disclosure may be the following polymer (4). Polymer (4): A glycidol adduct of polydiallylamine, in which at least a part of the nitrogen atoms of the amino groups of the glycidol adduct of the polydiallylamine is N-oxidized

[0027] Polymer (4) is a polymer having, in one or more embodiments, a structure derived from polydiallylamine and a structure derived from glycidol, and at least some of the nitrogen atoms in the polydiallylamine-derived structure have an N-oxide structure, and has the structure represented by formula (VI), and R 1 It is a polymer that contains a hydrogen atom.

[0028] The weight-average molecular weight of the polyamine-N-oxides of this disclosure is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 15,000 or more, even more preferably 20,000 or more, and even more preferably 40,000 or more, and similarly, preferably 200,000 or less, and more preferably 170,000 or less. In this disclosure, the weight-average molecular weight can be measured, for example, by the method described in the examples.

[0029] The content of the polyamine-N-oxide of the Disclosure in the wetting agent of the Disclosure is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, from the viewpoint of improving wettability, and preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less, from the viewpoint of economic efficiency. When the polyamine-N-oxide is a combination of two or more types, the polyamine-N-oxide content is the total content of those types.

[0030] In this disclosure, "content of each component in the wetting agent" refers to the content of each component at the time of use, that is, when the wetting agent is used on a silicon wafer.

[0031] (water) In one or more embodiments, the wetting agents of the present disclosure contain water in addition to the polyamine-N-oxide of the present disclosure. The water is preferably selected from deionized water, distilled water, and ultrapure water. The water content in the wetting agent of this disclosure may be the remainder obtained by subtracting the polyamine-N-oxide of this disclosure and any optional components described later from the total amount (100% by mass) of the wetting agent of this disclosure.

[0032] (Other ingredients) The wetting agent of this disclosure may further contain one or more water-soluble polymers other than the polyamine-N-oxide of this disclosure, basic compounds, pH adjusters, preservatives, organic solvents, chelating agents, anionic surfactants, cationic surfactants, and nonionic surfactants, to the extent that their function as a wetting agent is not impaired.

[0033] In one or more embodiments, the pH of the wetting agent of this disclosure is preferably 9 or higher, more preferably 9.5 or higher, even more preferably 10 or higher, and similarly preferably 12 or lower, more preferably 11.5 or lower, and even more preferably 11 or lower, from the viewpoint of improving the wettability of the wetting agent of this disclosure and improving the polishing speed when the wetting agent of this disclosure is used as a polishing solution for silicon wafers. In this disclosure, the pH is a value measured at 25°C. The pH can be measured, for example, by the method described in the examples.

[0034] The wetting agents of this disclosure may include forms that are manufactured as concentrates and diluted at the time of use, from the viewpoint of storage and transport. That is, this disclosure relates in one or more embodiments to concentrates for obtaining the wetting agents of this disclosure. The concentration of the wetting agent concentrate of this disclosure 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 viewpoint of manufacturing and transportation costs, and preferably 300 times or less, more preferably 200 times or less, even more preferably 150 times or less, and even more preferably 100 times or less, from the viewpoint of storage stability. The concentration ratio of the wetting agent concentrate in this disclosure means [solid content concentration of the wetting agent concentrate / solid content concentration of the wetting agent at the time of use]. Here, "solid content concentration of the wetting agent concentrate" is the ratio of the mass of components other than water in the wetting agent concentrate to the mass of the wetting agent concentrate, and "solid content concentration of the wetting agent at the time of use" is the ratio of the mass of components other than water in the wetting agent at the time of use to the mass of the wetting agent at the time of use. The concentrate of the wetting agent of this disclosure can be used after diluting it with water so that the content of each component at the time of use is as described above (i.e., the content of each component in the wetting agent at the time of use).

[0035] The wetting agents of this disclosure are, in one or more embodiments, wetting agents for semiconductor substrates. In one or more embodiments, the wetting agents for semiconductor substrates can be used for processing and polishing semiconductor substrates having various materials and shapes. Examples of semiconductor substrates include silicon wafers. In one or more embodiments, the wetting agents of this disclosure are preferably used for polishing silicon wafers, and more preferably for finishing silicon wafer polishing. The wetting agents of this disclosure can be used as is as a polishing solution for silicon wafers in one or more embodiments.

[0036] [Polishing solution for silicon wafers] In one embodiment, this disclosure relates to a silicon wafer polishing solution containing the wetting agent of this disclosure (hereinafter also referred to as "the polishing solution of this disclosure"). In one or more embodiments, the polishing solution of the present disclosure contains the wetting agent of the present disclosure, resulting in superior polishing speed when used for polishing silicon wafers. The silicon wafer polishing solution of this disclosure can be used as a wetter in one or more embodiments. Furthermore, in one or more embodiments, the polishing solution of this disclosure can polish silicon wafers even without containing abrasive particles such as silica particles or ceria particles, by containing the wetting agent of this disclosure.

[0037] Although the detailed mechanism of action of the polishing solution disclosed herein is not clear, it is presumed to be as follows. The polishing solution of this disclosure contains the wetting agent of this disclosure (hereinafter also referred to as "component A"). The polyamine-N-oxide of this disclosure, which is a component of component A, has many N-oxide structures in its molecule. As mentioned above, the N-oxide structure has high polarity but no charge, so the rigidification of the polymer chain due to repulsion between charged groups, which can occur in charged polymer compounds, does not occur. Therefore, the polyamine-N-oxide of this disclosure, due to its flexibility and high polarity, adsorbs to the silicon wafer at multiple points, and exhibits even higher polarity due to structures derived from one or more glycidyl group-containing compounds and acrylamide compounds selected from each other, thereby further improving the wettability of the silicon wafer surface. Furthermore, since the N-oxide structure is oxidizing, it oxidizes the silicon atoms of the silicon wafer, embrittles the surface of the silicon wafer, and even when polishing the silicon wafer with only the wetting agent of this disclosure (component A), a practical polishing speed can be achieved. However, this disclosure does not have to be construed as being limited to these mechanisms.

[0038] (Polyamine-N-oxide in polishing solution) The content of the polyamine-N-oxide of the present disclosure, which is a component of the wetting agent (component A) of the present disclosure, in the polishing solution of the present disclosure is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.005% by mass or more, relative to the total polishing solution of the present disclosure, from the viewpoint of increasing the polishing speed when using the silicon wafer polishing solution of the present disclosure, and from the viewpoint of economic efficiency, preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.05% by mass or less. If the polyamine-N-oxide of the present disclosure is a combination of two or more types, the content of the polyamine-N-oxide of the present disclosure is the total content of those types.

[0039] In this disclosure, "content of each component in the polishing solution" refers to the content of each component at the time of use, that is, when the polishing solution is used on a silicon wafer.

[0040] (Water in the polishing solution) The polishing solution of this disclosure contains water in one or more embodiments. Preferably, the water is selected from deionized water, distilled water, or ultrapure water. The water may be introduced as part of the wetting agent (component A) of this disclosure, or it may be added separately. The water content in the polishing solution of this disclosure may be the residue obtained by subtracting the polyamine-N-oxide of this disclosure and any optional components that may be added as needed from the total polishing solution (100% by mass).

[0041] (Basic compounds in polishing solution) In one or more embodiments, the polishing solution of the present disclosure preferably further contains a basic compound from the viewpoint of increasing the polishing speed when using the polishing solution of the present disclosure. That is, in one or more embodiments, the polishing solution of the present disclosure contains the wetting agent (component A) of the present disclosure, water, and a basic compound. A preferred example of the basic compound contained in the polishing solution of this disclosure (hereinafter also referred to as "component B") is at least one selected from alkali metal hydroxides, alkali metal carbonates, ammonia, and quaternary ammonium hydroxides, from the viewpoint of increasing the polishing speed when using the polishing solution of this disclosure. Among these, at least one selected from alkali metal hydroxides, ammonia, and quaternary ammonium hydroxides is more preferred, at least one selected from sodium hydroxide, potassium hydroxide, ammonia, and tetramethylammonium hydroxide is even more preferred, and ammonia is even more preferred. Component B may be one type or a combination of two or more types.

[0042] If the polishing solution of this disclosure contains a basic compound (component B), the content of component B in the polishing solution of this disclosure is preferably 1 ppm by mass or more, more preferably 5 ppm by mass or more, even more preferably 10 ppm by mass or more, and from the viewpoint of increasing the polishing speed when using the polishing solution of this disclosure, preferably 300 ppm by mass or less, more preferably 200 ppm by mass or less, and even more preferably 100 ppm by mass or less, relative to the total amount of the polishing solution of this disclosure. If component B is a combination of two or more types, the content of component B is the total content of those types. In this disclosure, 1% by mass is equal to 10,000 ppm by mass (the same applies hereinafter).

[0043] If the polishing solution of this disclosure contains a basic compound (component B), the mass ratio of the content of component B to the content of the polyamine-N-oxide of this disclosure (component B / polyamine-N-oxide of this disclosure) is preferably 0.01 or higher, more preferably 0.1 or higher, even more preferably 0.2 or higher, and from the viewpoint of increasing the polishing speed when using the polishing solution of this disclosure, preferably 10 or lower, more preferably 1 or lower, and even more preferably 0.6 or lower.

[0044] The polishing fluid of this disclosure may contain abrasive particles in one or more embodiments. Examples of abrasive particles that the polishing fluid of this disclosure may contain include silica and ceria. In one or more embodiments of the polishing fluid disclosed herein, a practical polishing speed can be achieved even without containing abrasive particles. Therefore, the abrasive particle content can be such that the abrasive particles do not contribute to polishing. In one or more embodiments, the abrasive content in the polishing solution of the present disclosure is preferably less than 100 ppm by mass, more preferably 50 ppm by mass or less, even more preferably 10 ppm by mass or less, even more preferably 1 ppm by mass or less, and even more preferably 0 ppm by mass, i.e., the polishing solution of the present disclosure does not contain abrasive particles, from the viewpoint of not leaving abrasive particles on the silicon wafer.

[0045] The polishing solution of the present disclosure may further contain at least one optional component selected from water-soluble polymer compounds other than the polyamine-N-oxide of the present disclosure, which is a component of the wetting agent (component A) of the present disclosure, pH adjusters, preservatives, water-soluble organic solvents, chelating agents, anionic surfactants, cationic surfactants, and nonionic surfactants, to the extent that the effect of the polishing solution of the present disclosure is not impaired.

[0046] From the viewpoint of increasing the polishing rate of the polishing solution of this disclosure, the pH of the polishing solution of this disclosure is preferably 9 or higher, more preferably 9.5 or higher, even more preferably 10 or higher, and similarly preferably 12 or lower, more preferably 11.5 or lower, and even more preferably 11 or lower. In this disclosure, the pH is the value measured at 25°C. The pH can be measured, for example, by the method described in the examples.

[0047] The polishing solutions of this disclosure may include forms that are manufactured as concentrates and diluted at the time of use, from the viewpoint of storage and transport. That is, this disclosure relates in one or more embodiments to concentrates for obtaining the polishing solutions of this disclosure. The concentration ratio of the concentrated polishing solution of this disclosure 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 viewpoint of manufacturing and transportation costs, and preferably 500 times or less, more preferably 300 times or less, even more preferably 200 times or less, and even more preferably 100 times or less, from the viewpoint of storage stability. The concentration ratio of the polishing solution concentrate in this disclosure means [solid content concentration of the polishing solution concentrate / solid content concentration of the polishing solution at the time of use]. Here, "solid content concentration of the polishing solution concentrate" is the ratio of the mass of components other than water in the polishing solution concentrate to the mass of the polishing solution concentrate, and "solid content concentration of the polishing solution at the time of use" is the ratio of the mass of components other than water in the polishing solution at the time of use to the mass of the polishing solution at the time of use. The concentrated polishing solution of this disclosure can be used after diluting it with water so that the content of each component at the time of use is as described above (i.e., the content of each component in the polishing solution at the time of use). The pH of the concentrated polishing solution of the polishing solution of the present disclosure is preferably 9 or higher, more preferably 9.5 or higher, even more preferably 10 or higher, and similarly, preferably 12 or lower, more preferably 11.5 or lower, and even more preferably 11 or lower, from the viewpoint of increasing the polishing rate when preparing the polishing solution of the present disclosure. In the present disclosure, the pH is the value measured at 25°C as described above.

[0048] The polishing solution of this disclosure can be obtained by compounding the wetting agent (component A) of this disclosure with water, and optionally a basic compound (component B). Accordingly, in other embodiments, this disclosure relates to a method for manufacturing a polishing solution for silicon wafers, which includes a step of compounding component A and water. In this disclosure, "compounding" includes mixing component A, water, and optionally component B and other components simultaneously or in any order. The compounding can be carried out, for example, by stirring with a magnetic rotor using a magnetic stirrer, stirring with anchor blades or paddle blades, or by using a homomixer, homogenizer, ultrasonic disperser, etc.

[0049] The polishing solution of this disclosure can be used, for example, in a polishing step for polishing a silicon wafer in the manufacturing process of a semiconductor substrate, or in a silicon wafer polishing method that includes a polishing step for polishing a silicon wafer. The polishing process for polishing the silicon wafer includes a lapping (rough polishing) step to flatten the silicon wafer obtained by slicing a silicon single crystal ingot into a thin disc shape, and a finish polishing step to make the surface of the silicon wafer mirror-like after etching the lapped silicon wafer. The polishing solution of this disclosure is more preferably used in the finish polishing step.

[0050] [Polishing solution kit] This disclosure relates, in one aspect, to a kit for manufacturing the polishing solution of this disclosure (hereinafter also referred to as the "kit of this disclosure"). According to the kit of this disclosure, a polishing solution can be obtained that can achieve both an improved polishing speed of silicon wafers and improved wettability of silicon wafers. Examples of the kits of the present disclosure include, in one or more embodiments, a polishing solution kit containing a solution comprising the polyamine N-oxide of the present disclosure and water. The polishing solution kit may optionally contain other components as described above. If the polishing solution kit is referred to as polishing solution kit A, then when polishing solution kit A is used for silicon wafer polishing, it can be mixed with other components and, optionally, water to form the polishing solution of the present disclosure.

[0051] [Manufacturing method for semiconductor devices] This disclosure relates, in one embodiment, to a method for manufacturing a semiconductor device (hereinafter also referred to as "the semiconductor device manufacturing method of this disclosure") which includes a step of polishing a silicon wafer using the polishing solution of this disclosure. In this disclosure, "semiconductor device" refers to an electronic component that uses a semiconductor. The silicon wafers polished in the aforementioned silicon wafer polishing process include silicon wafers obtained by slicing a silicon single crystal ingot into a thin disc shape, and silicon wafers that have undergone a lapping process to flatten the sliced ​​silicon wafer and an etching process to etch the silicon wafer that has undergone the lapping process. In the semiconductor device manufacturing method of the present disclosure, the silicon wafer used in the step of polishing the silicon wafer with the polishing solution of the present disclosure is preferably a silicon wafer that has undergone a lapping step in which a silicon wafer obtained by slicing a silicon ingot is planarized, and an etching step in which the silicon wafer that has undergone the lapping step is etched. In one or more embodiments, the polishing step for polishing the silicon wafer is a finishing polishing step. [Examples]

[0052] The present disclosure will be further described below with reference to examples, but these are illustrative and the disclosure is not limited to these examples.

[0053] 1. Preparation of wetting agent (Concentrates of wetting agents 1-3, 5-7, and comparative concentrate of wetting agent 1) 1.5 parts by mass of polyamine-N-oxides 1-6 or water-soluble polymers (HEC) shown in Table 2 were mixed with 98.5 parts by mass of ultrapure water to obtain concentrates of wetting agents 1-3, 5-7, and a concentrate of comparative wetting agent 1. (Concentrated wetting agent 4) A concentrated wettant 4 was obtained by mixing 0.5 parts by mass of polyamine-N-oxide 3, shown in Table 2, with 99.5 parts by mass of ultrapure water. The pH of each wetting agent concentrate at 25°C ranged from 10.6 to 11.0. The pH values ​​were measured at 25°C using a pH meter (Toa Denpa Kogyo Co., Ltd., HM-30G), and were recorded one minute after immersing the pH meter electrode in the wetting agent concentrate.

[0054] The HEC and polyamine-N-oxide 1-6 used in the preparation of the concentrates of each wetting agent were as follows: HEC: Hydroxyethylcellulose [Sumitomo Seika Co., Ltd., SE-400, weight-average molecular weight 250,000] Polyamine-N-oxide 1 [Manufactured by Kao Corporation] Synthesis method: 5.38 g of polyethyleneimine SP-200 (manufactured by Nippon Shokubai Co., Ltd., weight-average molecular weight 16,000, amine value: 18 mmol / g·solid) (amine ratio primary amine: secondary amine: tertiary amine = 35:35:30 (mol%)) and 10 g of water were placed in a 100 mL round-bottom flask. 12.0 g of glycidol (manufactured by Kanto Chemical Co., Ltd., purity >95%) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 2 hours to obtain a reaction solution containing the reaction product of polyethyleneimine and glycidol. 15.8 g of 35% hydrogen peroxide (manufactured by ADEKA) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 1 shown in Table 1. Polyamine-N-oxide 2 [Manufactured by Kao Corporation] Synthesis method: In a 2L three-necked flask, 60.0g of polyethyleneimine SP-200 (manufactured by Nippon Shokubai Co., Ltd., weight-average molecular weight 16,000, amine value: 18 mmol / g·solid), amine ratio (primary amine:secondary amine:tertiary amine = 35:35:30 (mol%)), and 205g of water were placed. Under a nitrogen atmosphere, 145g of N,N-dimethylacrylamide (manufactured by Fujifilm Wako Reagents Co., Ltd., reagent grade) was added dropwise over 1 hour at 60°C, and the mixture was then stirred at 60°C for 5 hours to obtain a reaction solution containing the reaction product of polyethyleneimine and N,N-dimethylacrylamide. To this reaction solution, 271g of 35% hydrogen peroxide (manufactured by ADEKA Corporation) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 2 shown in Table 1. Polyamine-N-oxide 3 [Manufactured by Kao Corporation] Synthesis method: In a 2L three-necked flask, 60.0g of polyethyleneimine HM-2000 (manufactured by Nippon Shokubai Co., Ltd., weight-average molecular weight 54,000, amine value: 18 mmol / g·solid) (amine ratio primary amine: secondary amine: tertiary amine = 1:1:0.9 (mol%)) and 205g of water were placed. Under a nitrogen atmosphere, 145g of N,N-dimethylacrylamide (manufactured by Fujifilm Wako Reagents Co., Ltd., reagent grade) was added dropwise over 1 hour at 60°C, and the mixture was then stirred at 60°C for 5 hours to obtain a reaction solution containing the reaction product of polyethyleneimine and N,N-dimethylacrylamide. To this reaction solution, 271g of 35% hydrogen peroxide (manufactured by ADEKA Corporation) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 3 shown in Table 1. Polyamine-N-oxide 4 [Manufactured by Kao Corporation] Synthesis method: In a 500 mL three-necked flask, 14.9 g of polyethyleneimine SP-018 (manufactured by Nippon Shokubai Co., Ltd., weight-average molecular weight 5,800, amine value: 19 mmol / g·solid, amine ratio primary amine: secondary amine: tertiary amine = 35:35:30 (mol%)) and 50.8 g of water were placed. Under a nitrogen atmosphere, 36.2 g of N,N-dimethylacrylamide (manufactured by Fujifilm Wako Reagents Co., Ltd., reagent grade) was added dropwise over 1 hour at 60°C, and the mixture was then stirred at 60°C for 5 hours to obtain a reaction solution containing the reaction product of polyethyleneimine and N,N-dimethylacrylamide. 33.6 g of 35% hydrogen peroxide (manufactured by ADEKA Corporation) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 4 shown in Table 1. Polyamine-N-oxide 5 [Manufactured by Kao Corporation] Synthesis method: In a 500 mL three-necked flask, 14.8 g of polyethyleneimine SP-018 (manufactured by Nippon Shokubai Co., Ltd., weight-average molecular weight 5,800, amine value: 19 mmol / g·solid, amine ratio primary amine: secondary amine: tertiary amine = 35:35:30 (mol%)) and 50.6 g of water were placed. Under a nitrogen atmosphere, 36.0 g of N,N-dimethylacrylamide (manufactured by Fujifilm Wako Reagents Co., Ltd., reagent grade) was added dropwise over 1 hour at 60°C, and the mixture was then stirred at 60°C for 5 hours to obtain a reaction solution containing the reaction product of polyethyleneimine and N,N-dimethylacrylamide. To this reaction solution, 16.7 g of 35% hydrogen peroxide (manufactured by ADEKA Corporation) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 5 shown in Table 1. Polyamine-N-oxide 6 [Manufactured by Kao Corporation] Synthesis method: In a 500 mL three-necked flask, 20 g of polyallylamine (manufactured by Nitto Boseki, weight average weight 5,000 g, amine value 17 mmol / g·solid, amine ratio primary amine:secondary amine:tertiary amine = 100:0:0 (mol%)) and 168 g of water were placed. Under a nitrogen atmosphere, 76 g of glycidol was added dropwise over 1 hour at 60°C, and the mixture was then stirred at 60°C for 1 hour to obtain a reaction solution containing the reaction product of polyallylamine and glycidol. 90 g of 35% hydrogen peroxide (manufactured by ADEKA) was added dropwise over 1 hour, and the mixture was stirred at 60°C for 6 hours to prepare the polyamine-N-oxide 6 shown in Table 1.

[0055] [Table 1]

[0056] 2. Method for measuring the ratio of N-oxide structures at nitrogen atoms in the polyamine-N-oxide of the present disclosure The values ​​calculated using the following formula were used as the ratio of N-oxide structures at the nitrogen atoms of the polyamine-N-oxide in this disclosure. The ratio (%) of N-oxide structures at the nitrogen atom of the polyamine-N-oxide in this disclosure = 100 - (total amine value (after hydrogen peroxide reaction)) / (total amine value (before hydrogen peroxide reaction)) × 100 The total amine value is the amount of hydrochloric acid required to neutralize the total amount of primary, secondary, and tertiary amines in 1 g of an amino group-containing compound, converted to the number of milligrams of potassium hydroxide. In calculating the ratio of N-oxide structures at the nitrogen atom of the polyamine-N-oxide of this disclosure, the total amine value is determined by the following procedure. A polyamine-N-oxide (amino group-containing compound for measuring total amine value (after hydrogen peroxide reaction)) or a reaction product of a polyamine N-oxide (amino group-containing compound for measuring total amine value (before hydrogen peroxide reaction)) selected from one or more glycidyl group-containing compounds and acrylamide compounds of the polyamine disclosed herein was accurately measured into a 100 mL beaker as a sample and dissolved in water. Potentiometric titration was performed using a HM-41K pH meter (manufactured by Toa DKK Co., Ltd.) with a 0.2 mol / L alcoholic hydrochloric acid standard solution. A blank test was performed simultaneously and calculated using the following formula. Total amine value (mgKOH / g.solid) = (XY) × M × f × 56.108 / Sample amount (g) X: Titration volume (mL) for this test Y: Titration volume of blank test (mL) M: Molar concentration (mol / L) of alcoholic hydrochloric acid standard solution f: Factor of alcoholic hydrochloric acid standard solution 56.108: Molecular weight of KOH (g / mol)

[0057] 3. Measurement of the weight-average molecular weight of the polyamine-N-oxide or water-soluble polymers of this disclosure The weight-average molecular weight of the polyamine-N-oxide or water-soluble polymers in this disclosure was calculated based on the peaks in the chromatogram obtained by applying gel permeation chromatography (GPC) under the following conditions. <Measurement conditions for polyamine-N-oxide or water-soluble polymers> Equipment: HLC-8320 GPC (manufactured by Tosoh Corporation, with integrated detector) Column: α-M + α-M (cation) Eluent: 0.15M Na2SO4 / 1% CH3COOH Flow rate: 1mL / min Column temperature: 40℃ Detector: Schodex RI SE-61 differential refractive index detector Standard substance: Monodisperse pullulan with a known molecular weight

[0058] 4. Reaction rate of nitrogen atoms in the polyamine-derived structures of this disclosure The ratio of nitrogen atoms in the polyamine-derived structure of this disclosure that react with a glycidyl group-containing compound or an acrylamide compound (reaction rate of nitrogen atoms) is: 13 The ratio (mol%) of primary, secondary, and tertiary nitrogen atoms in the polyamine-derived structure of this disclosure, calculated by 13C-NMR measurement, was estimated from the changes before and after reaction with a glycidyl group-containing compound.

[0059] 5. Evaluation of Wetting Agents in Examples 1-7 and Comparative Example 1 (1) Preparation of wetting agent One part by mass of the concentrate of the wetting agent obtained above was mixed with 0.0107 parts by mass of aqueous ammonia [28% by mass aqueous ammonia, manufactured by Kishida Chemical Co., Ltd., reagent grade] so that the ammonia content was 0.003% by mass. The mixture was then further mixed with ultrapure water to a total of 100 parts by mass to obtain wetting agents 1 to 7 of the present disclosure and comparative wetting agent 1. The content of each component (by mass % or by mass ppm, effective content) in Table 2 is the content of each component contained in the wetting agent obtained by diluting the concentrate of the above wetting agent. The water content in each wetting agent is the residue obtained by removing the polyamine-N-oxide or water-soluble polymer and ammonia from the total amount of wetting agent (100% by mass). The obtained wetting agents 1 to 7 and comparative wetting agent 1 were used as polishing fluids to be supplied to a polishing machine when polishing silicon wafers as described later. That is, the polishing fluids of Examples 1 to 7 and Comparative Example 1 did not contain abrasive particles. The pH of the obtained wetting agents of the present disclosure at 25°C was 10.2. The pH value was measured at 25°C using a pH meter (Toa Denpa Kogyo Co., Ltd., HM-30G), and is the value obtained one minute after immersing the pH meter's electrode in the wetting agent. The obtained wetting agent was subjected to a polishing machine, and its wettability and polishing speed were evaluated as shown below.

[0060] (2) Polishing method etc. Each wetting agent was filtered using a filter (compact cartridge filter "MCP-LX-C10S", manufactured by Advantech Co., Ltd.) immediately before polishing, and then the following silicon substrates were polished and cleaned under the following polishing conditions. <Silicon wafer to be polished> Single-crystal silicon substrate [200mm diameter, single-sided mirror-finished silicon substrate, conduction type: P, crystal orientation: 100, resistivity: 0.1Ω·cm or more and less than 100Ω·cm] The above single-crystal silicon wafers were pre-polished using a commercially available polishing solution (GLANZOX 1302, manufactured by Fujimi Incorporated). The haze of the single-crystal silicon wafers after rough polishing and before finishing polishing was 2-3 ppm.

[0061] <Finishing polishing conditions> Grinding machine: Single-sided 8-inch grinding 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 wafer polishing pressure: 100 g / cm² 2 Plate rotation speed: 60 rpm Polishing time: 2 minutes Supply rate of wetting agents 1-7 and comparative wetting agent 1: 150g / min Temperature of wetting agents 1-7 and comparative wetting agent 1: 23°C Carrier rotation speed: 62 rpm

[0062] <Cleaning method> After final polishing, the silicon wafers were subjected to ozone cleaning and dilute hydrofluoric acid cleaning as described below. For ozone cleaning, an aqueous solution containing 20 ppm ozone was sprayed from a nozzle at a flow rate of 1 L / min towards the center of the silicon wafer rotating at 600 rpm for 3 minutes. The temperature of the ozonated water was kept at room temperature. Next, dilute hydrofluoric acid cleaning was performed. For dilute hydrofluoric acid cleaning, an aqueous solution containing 0.5 mass% ammonium hydrogen fluoride (special grade, Nacalai Tesque Co., Ltd.) was sprayed from a nozzle at a flow rate of 1 L / min towards the center of the silicon wafer rotating at 600 rpm for 6 seconds. The above ozone cleaning and dilute hydrofluoric acid cleaning were performed as one set, for a total of two sets, and finally, spin drying was performed. For spin drying, the silicon wafer was rotated at 1,500 rpm.

[0063] (3) Evaluation of wettability The wet area of ​​each silicon wafer immediately after polishing was calculated as the ratio of the wet area to the area of ​​one side of the silicon wafer. The results are shown in Table 2.

[0064] (4) Evaluation of polishing speed The mass of each silicon wafer before and after polishing was measured using a precision balance (Sartorius BP-210S). The obtained mass difference was divided by the silicon wafer density, area, and polishing time to determine the single-sided polishing rate per unit time. The results are shown in Table 2. Note that the mass of the silicon wafer after polishing refers to the mass of the silicon wafer after the above-mentioned finish polishing and cleaning.

[0065] [Table 2]

[0066] As shown in Table 2, the polishing solutions of Examples 1 to 7, which contained polyamine-N-oxides 1 to 6 (wetting agents 1 to 7), showed improved wettability to silicon wafers and improved polishing speed compared to the polishing solution of Comparative Example 1, which contained HEC (comparative wetting agent 1). [Industrial applicability]

[0067] The wettability of a silicon wafer surface can be improved by using the wetting agent of this disclosure. The polishing speed can be improved by using the wetting agent of this disclosure for polishing a silicon wafer. Therefore, a polishing solution containing the wetting agent of this disclosure is useful in various processes of semiconductor manufacturing, and is particularly useful as a polishing solution composition for the final polishing of silicon wafers.

Claims

1. A wetting agent containing a polyamine-N-oxide having a structure derived from one polyamine selected from polyethyleneimine, polyallylamine, and polydiallylamine, and a structure derived from one or more compounds selected from glycidyl group-containing compounds and acrylamide compounds.

2. The wetting agent according to claim 1, wherein the structure derived from the glycidyl group-containing compound is a structure derived from glycidol.

3. The wetting agent according to claim 1, wherein the structure derived from the acrylamide compound is at least one selected from the structure derived from N,N-dimethylacrylamide and the structure derived from N,N-diethylacrylamide.

4. The wetting agent according to claim 1, wherein the polyamine-N-oxide has one or more structures selected from any of the following formulas (I) to (VI). 【Chemistry 1】 In the above formula, R 1 , R 2 Each of these independently represents either a hydrogen atom, an alkyl group, an aryl group, or an alkylaryl group.

5. The wetting agent according to claim 1, wherein the polyamine-N-oxide is one or more selected from any of the following polymers (1) to (3). Polymer (1): A glycidol adduct of polyethyleneimine, wherein at least a portion of the nitrogen atoms of the amino group of the glycidol adduct of polyethyleneimine is N-oxideized. Polymer (2): An N,N-dimethylacrylamide adduct of polyethyleneimine, wherein at least a portion of the nitrogen atoms of the amino group of the N,N-dimethylacrylamide adduct of polyethyleneimine is N-oxideized. Polymer (3): A glycidol adduct of polyallylamine, wherein at least a portion of the nitrogen atoms of the amino group of the glycidol adduct of polyallylamine is N-oxideized.

6. The wetting agent according to claim 1, wherein the weight-average molecular weight of the polyamine-N-oxide is 2,000 or more and 200,000 or less.

7. The wetting agent according to claim 1, which is used for polishing silicon wafers.

8. A polishing solution for silicon wafers containing the wetting agent described in any one of claims 1 to 6.

9. A method for manufacturing a semiconductor device, comprising the step of polishing a silicon wafer using the silicon wafer polishing solution described in claim 8.

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