Method for producing a wetting agent for semiconductors containing a polyvinyl alcohol composition

Abstract

To provide a polyvinyl alcohol composition in which generation of an aggregate is effectively suppressed in a manufacturing method of a semiconductor wetting agent containing a polyvinyl alcohol composition.SOLUTION: A method for manufacturing a semiconductor wetting agent including a polyvinyl alcohol composition, in which the polyvinyl alcohol composition is obtained through a submerged addition step of adding, into any one of a first solution containing polyvinyl alcohol and water and a second solution other than the first solution, any other of the first solution and the second solution is added in liquid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a wetting agent for semiconductors, which comprises a polyvinyl alcohol composition. [Background technology]

[0002] Polyvinyl alcohol is a hydrophilic synthetic resin that is often used in the form of a fluid solution (aqueous solution) as a textile raw material, a sizing agent, a paint, an adhesive, an emulsifier, etc.

[0003] Typically, polyvinyl alcohol can be dissolved in water by dispersing it in water and then stirring the resulting polyvinyl alcohol dispersion at a high temperature (e.g., 80°C or higher). However, it is known that if the polyvinyl alcohol is not dispersed in water before dissolving, it will form lumps. The lumps are thought to occur because the surfaces of polyvinyl alcohol particles swell and become semi-dissolved when they come into contact with water, and the semi-dissolved polyvinyl alcohol particles then adhere to each other to form large lumps. Such lumps are extremely difficult to dissolve in solvents, as only the surface of the lumps dissolves and no water penetrates the interior. Therefore, aqueous polyvinyl alcohol solutions containing lumps present the problem of being difficult to use in various applications.

[0004] To solve these problems, various methods for producing aqueous polyvinyl alcohol solutions have been proposed. For example, Patent Document 1 discloses a method for improving the dispersibility and solubility of polyvinyl alcohol by adding a surfactant to polyvinyl alcohol. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-94431 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it has been found that even when a polyvinyl alcohol aqueous solution without agglomerates is obtained, when other aqueous solutions are added and mixed with the polyvinyl alcohol aqueous solution, aggregates are generated. For example, when such a polyvinyl alcohol aqueous solution is used as a wetting agent for semiconductors or a polishing composition, solids such as aggregates will damage the polishing target, so it is necessary to remove the solids in advance by filtration or the like. A polyvinyl alcohol aqueous solution containing aggregates has very poor filterability, so that filtration takes a long time, yield is reduced, and productivity is significantly reduced.

[0007] Therefore, an object of the present invention is to provide a polyvinyl alcohol composition in which the generation of aggregates is effectively suppressed in a method for producing a wetting agent for semiconductors containing the polyvinyl alcohol composition (aqueous polyvinyl alcohol solution). [Means for solving the problem]

[0008] In order to solve the above-mentioned new problems, the present inventors have conducted extensive research and found that the above-mentioned problems can be solved by a method for producing a wetting agent for semiconductors and / or a polishing composition containing a polyvinyl alcohol composition, wherein the polyvinyl alcohol composition is obtained by a submerged addition step of submerging either a first liquid containing polyvinyl alcohol and water or a second liquid other than the first liquid, and the other of the first liquid and the second liquid is added to the first liquid, thereby completing the present invention. [Effects of the Invention]

[0009] According to the present invention, in a method for producing a wetting agent for semiconductors and / or a polishing composition containing a polyvinyl alcohol composition, a polyvinyl alcohol composition is provided in which the generation of aggregates is effectively suppressed. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a diagram showing a schematic diagram of an apparatus used in an experiment on submerged addition. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention relates to a method for producing a semiconductor wetting agent and / or polishing composition containing a polyvinyl alcohol composition, wherein the polyvinyl alcohol composition is obtained by a submerged addition step in which either a first liquid containing polyvinyl alcohol and water or a second liquid other than the first liquid is added to the other of the first liquid and the second liquid. The semiconductor wetting agent and / or polishing composition containing the polyvinyl alcohol composition obtained by this method exhibits reduced agglomeration and excellent filterability. According to one embodiment, the semiconductor wetting agent and / or polishing composition containing the polyvinyl alcohol composition obtained by this method has excellent storage stability.

[0012] The mechanism by which such an effect is obtained is believed to be as follows. However, the following mechanism is merely speculation, and the scope of the present invention is not limited thereby. In the production method of the present invention, a second liquid is submerged into a first liquid containing polyvinyl alcohol, or a first liquid containing polyvinyl alcohol is submerged into a second liquid. This is thought to suppress bubbles that form on the liquid surface when the liquids are added, and to suppress the generation of aggregates due to the dried matter of the bubbles.

[0013] In this specification, "submerged addition" means adding one liquid directly to another liquid, for example, by introducing a supply pipe or the like into one liquid and supplying the other liquid into the first liquid through the supply pipe. The form of submerged addition is not limited to the above-mentioned form, as long as it is a method that allows direct addition into the liquid, not onto the liquid surface.

[0014] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. In this specification, unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20°C or higher and 25°C or lower) and a relative humidity of 40% RH or higher and 50% RH or lower.

[0015] <Method for producing polyvinyl alcohol composition> First, a method for producing a polyvinyl alcohol composition used in the semiconductor wetting agent and / or polishing composition of the present invention will be described. The method for producing a polyvinyl alcohol composition described herein can be directly applied to the method for producing a semiconductor wetting agent and / or polishing composition of the present invention. That is, in the present invention, when the polyvinyl alcohol composition does not contain abrasive grains, the method for producing a polyvinyl alcohol composition can be directly applied to the method for producing a semiconductor wetting agent containing the polyvinyl alcohol composition. The polyvinyl alcohol composition can also be used as a semiconductor wetting agent as is. In the present invention, when the polyvinyl alcohol composition contains abrasive grains, the method for producing a polyvinyl alcohol composition can be directly applied to the method for producing a polishing composition containing the polyvinyl alcohol composition. The polyvinyl alcohol composition can also be used as a polishing composition as is. Therefore, according to one embodiment of the present invention, the method for producing a semiconductor wetting agent and / or polishing composition containing a polyvinyl alcohol composition can also be rephrased as the method for producing a semiconductor wetting agent and / or polishing composition containing polyvinyl alcohol.

[0016] In the polyvinyl alcohol composition of the present invention, the mixing step of mixing a first liquid containing polyvinyl alcohol and water with a second liquid other than the first liquid to obtain the polyvinyl alcohol composition includes an in-liquid addition step of adding the other of the first liquid and the second liquid to either the first liquid or the second liquid.

[0017] [First liquid] The first liquid contains polyvinyl alcohol and water, and may further contain, as necessary, known additives such as a surfactant, a water-soluble polymer other than polyvinyl alcohol, a chelating agent, an organic acid, an organic acid salt, an inorganic acid, an inorganic acid salt, a pH adjuster, an oxidizing agent, a metal corrosion inhibitor, an antiseptic, and an antifungal agent, and a solvent other than water.

[0018] (Polyvinyl alcohol) In the present invention, polyvinyl alcohol may contain only vinyl alcohol units (hereinafter also referred to as "VA units") as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units"). A vinyl alcohol unit is a structural moiety represented by the chemical formula -CH2-CH(OH)-. Polyvinyl alcohol may be a random copolymer, block copolymer, alternating copolymer, or graft copolymer containing VA units and non-VA units. Polyvinyl alcohol may contain only one type of non-VA unit, or may contain two or more types of non-VA units.

[0019] The polyvinyl alcohol may be unmodified polyvinyl alcohol (non-modified PVA) or modified polyvinyl alcohol (modified PVA). Here, non-modified PVA refers to polyvinyl alcohol produced by hydrolysis (saponification) of polyvinyl acetate, and substantially free of repeating units other than the repeating unit (-CH-CH(OCOCH)-) of a structure formed by polymerization of vinyl acetate and VA units.

[0020] The degree of saponification of the unmodified PVA may be preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more. In particular, when used as a polishing composition, the degree of saponification of the unmodified PVA is preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 99.3 mol% or more. Therefore, according to one embodiment of the present invention, unmodified PVA having a degree of saponification of 95 mol% or more (preferably 98 mol% or more, more preferably 99.3 mol% or more) can be preferably used. PVA with a high degree of saponification tends to generate clumps more easily, making it suitable for use in the present invention. In this specification, the degree of saponification is a value obtained by measurement in accordance with JIS-K6726 (1994). Specifically, the degree of saponification refers to the proportion of acetoxy groups (-OCOCH3) in polyvinyl acetate that have been converted to hydroxy groups (-OH), and is expressed as a percentage of the number of hydroxy groups relative to the total number of acetoxy groups and hydroxy groups in polyvinyl alcohol.

[0021] Non-VA units that may be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl monomers or N-(meth)acryloyl monomers, as described below, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, and repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms. A preferred example of the N-vinyl monomer is N-vinylpyrrolidone. A preferred example of the N-(meth)acryloyl monomer is N-(meth)acrylomorpholine. The alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate.

[0022] The polyvinyl alcohol may also be a modified PVA in which some of the VA units contained in the polyvinyl alcohol are acetalized with an aldehyde. As the aldehyde, for example, an alkyl aldehyde can be preferably used, and an alkyl aldehyde having an alkyl group having from 1 to 7 carbon atoms is preferred, and among these, acetaldehyde, n-propyl aldehyde, n-butyl aldehyde, and n-pentyl aldehyde are preferred. As the polyvinyl alcohol, a cation-modified polyvinyl alcohol in which a cationic group such as a quaternary ammonium structure has been introduced may also be used. Examples of the cation-modified polyvinyl alcohol include those in which a cationic group derived from a monomer having a cationic group, such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt, has been introduced.

[0023] The polyvinyl alcohol may also be a modified PVA containing VA units and non-VA units having at least one structure selected from an oxyalkylene group, a carboxy group, a sulfo group, an amino group, a hydroxy group, an amide group, an imide group, a nitrile group, an ether group, an ester group, and salts thereof.

[0024] The ratio of the number of moles of VA units to the number of moles of all repeating units constituting polyvinyl alcohol may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. While not particularly limited, in some embodiments, the ratio of the number of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting polyvinyl alcohol may be VA units. Here, "substantially 100%" means that non-VA units are not contained in polyvinyl alcohol, at least intentionally. Typically, the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (e.g., less than 1%), including 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting polyvinyl alcohol may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0025] The content of VA units in polyvinyl alcohol (content by weight) may be, for example, 5% by weight or more, 10% by weight or more, 20% by weight or more, or 30% by weight or more. While not particularly limited, in some embodiments, the content of VA units may be 50% by weight or more (e.g., more than 50% by weight), 70% by weight or more, or 80% by weight or more (e.g., 90% by weight or more, 95% by weight or more, or 98% by weight or more). Substantially 100% by weight of the repeating units constituting polyvinyl alcohol may be VA units. Here, "substantially 100% by weight" means that non-VA units are not included as repeating units constituting polyvinyl alcohol, at least intentionally. Typically, the content of non-VA units in polyvinyl alcohol is less than 2% by weight (e.g., less than 1% by weight). In other embodiments, the content of VA units in polyvinyl alcohol may be, for example, 95% by weight or less, 90% by weight or less, 80% by weight or less, or 70% by weight or less.

[0026] Polyvinyl alcohol may contain multiple polymer chains with different VA unit contents within the same molecule. Here, polymer chain refers to a segment that constitutes part of a single polymer molecule. For example, polyvinyl alcohol may contain polymer chain A with a VA unit content of more than 50% by weight and polymer chain B with a VA unit content of less than 50% by weight (i.e., a non-VA unit content of more than 50% by weight) within the same molecule.

[0027] The polymer chain A may contain only VA units as repeating units, or may contain non-VA units in addition to VA units. The content of VA units in the polymer chain A may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of VA units in the polymer chain A may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting the polymer chain A may be VA units.

[0028] Polymer chain B may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain B may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of non-VA units in polymer chain B may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting polymer chain B may be non-VA units.

[0029] Examples of polyvinyl alcohol containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The graft copolymer may be a graft copolymer having a structure in which polymer chain B (side chain) is grafted to polymer chain A (main chain), or a graft copolymer having a structure in which polymer chain A (side chain) is grafted to polymer chain B (main chain). In one embodiment, polyvinyl alcohol having a structure in which polymer chain B is grafted to polymer chain A can be used.

[0030] Examples of polymer chain B include polymer chains having a repeating unit derived from an N-vinyl type monomer as the main repeating unit, polymer chains having a repeating unit derived from an N-(meth)acryloyl type monomer as the main repeating unit, and polymer chains having an oxyalkylene unit as the main repeating unit. In this specification, the term "main repeating unit" refers to a repeating unit contained in an amount of more than 50% by weight, unless otherwise specified.

[0031] A suitable example of the polymer chain B is a polymer chain having an N-vinyl monomer as the main repeating unit, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl monomers in the N-vinyl polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of the polymer chain B may be repeating units derived from N-vinyl monomers.

[0032] In this specification, examples of N-vinyl monomers include monomers having a nitrogen-containing heterocycle (e.g., a lactam ring) and N-vinyl linear amides. Specific examples of N-vinyl lactam monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione. Specific examples of N-vinyl linear amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. Polymer chain B may be, for example, an N-vinyl polymer chain in which more than 50% by weight (e.g., 70% by weight or more, 85% by weight or more, or 95% by weight or more) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinylpyrrolidone units.

[0033] Another example of polymer chain B is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl-type monomer, i.e., an N-(meth)acryloyl-based polymer chain. The content of repeating units derived from N-(meth)acryloyl-type monomers in the N-(meth)acryloyl-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of polymer chain B may be repeating units derived from N-(meth)acryloyl-type monomers.

[0034] In this specification, examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0035] Another example of the polymer chain B is a polymer chain containing an oxyalkylene unit as a main repeating unit, i.e., an oxyalkylene-based polymer chain. The content of the oxyalkylene unit in the oxyalkylene-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or even 95% by weight or more. Substantially all of the repeating units contained in the polymer chain B may be oxyalkylene units.

[0036] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, oxybutylene units, etc. Such oxyalkylene units may be repeating units derived from the corresponding alkylene oxides. The oxyalkylene units contained in the oxyalkylene polymer chain may be one type or two or more types. For example, the oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, the oxyalkylene units may be a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer of the corresponding alkylene oxides.

[0037] Other examples of the polymer chain B include polymer chains containing, as main repeating units, alkyl vinyl ether units, structural units obtained by acetalizing polyvinyl alcohol with an aldehyde, etc. Among these, the polymer chain B is preferably selected from the group consisting of vinyl ether units having an alkyl group having from 1 to 10 carbon atoms (alkyl vinyl ether units), vinyl ester units derived from monocarboxylic acids having from 1 to 7 carbon atoms (monocarboxylic acid vinyl ester units), and structural units obtained by acetalizing polyvinyl alcohol with an aldehyde having an alkyl group having from 1 to 7 carbon atoms.

[0038] Examples of vinyl ether units having an alkyl group having from 1 to 10 carbon atoms include propyl vinyl ether units, butyl vinyl ether units, 2-ethylhexyl vinyl ether units, etc. Examples of vinyl ester units derived from monocarboxylic acids having from 1 to 7 carbon atoms include vinyl propanoate units, vinyl butanoate units, vinyl pentanoate units, vinyl hexanoate units, etc.

[0039] The polyvinyl alcohol used in the polishing composition and / or wetting agent for semiconductors disclosed herein is preferably unmodified PVA (non-modified PVA).

[0040] The weight average molecular weight (Mw) of polyvinyl alcohol is not particularly limited. The Mw of polyvinyl alcohol is usually 2×10 3 That's 5 x 10 3 May be greater than 1 x 10 4 or more. As the Mw of polyvinyl alcohol increases, the wettability of the surface after polishing and / or rinsing tends to increase. In addition, as the Mw of polyvinyl alcohol increases, the dispersibility of polyvinyl alcohol tends to decrease, so the significance of applying the present invention becomes greater. From this perspective, the Mw of polyvinyl alcohol is 3 × 10 4 It is preferable that the ratio is 4×10 or more, and more preferably 4×10 4 or more, and more preferably 5×10 4 More preferably, 6×10 4 or more (e.g., 6.5 × 10 4 That's all.

[0041] The weight average molecular weight (Mw) of polyvinyl alcohol is usually 100 × 10 4 The following is appropriate: 30 x 10 4 Less than 20 x 10 is preferable. 4 Less than (e.g., 15 × 10 4 From the viewpoint of achieving both a polishing rate and surface protection of the substrate, the Mw of the polyvinyl alcohol may be 10×10 4 May be less than 8 x 10 4 It may be the following:

[0042] In this specification, the weight average molecular weight (Mw) is a value based on aqueous gel permeation chromatography (GPC) (aqueous, polyethylene oxide equivalent). As a GPC measuring device, a Tosoh Corporation model "HLC-8320GPC" can be used. The measurement conditions are, for example, as follows:

[0043] [GPC measurement conditions] Sample concentration: 0.1% by weight Column: TSKgel GMPWXL Detector: differential refractometer Eluent: 100mM sodium nitrate aqueous solution / acetonitrile = 108 / 02 Flow rate: 1mL / min Measurement temperature: 40℃ Sample injection volume: 200 μL The degree of polymerization of polyvinyl alcohol is generally about 100 to 10,000, but particularly when used as a polishing composition, it is preferably 300 or more, more preferably 500 or more, even more preferably 1500 or more, and specifically 2000 or more. Moreover, the degree of polymerization of polyvinyl alcohol is preferably 4000 or less, more preferably 3000 or less, even more preferably 2900 or less. When the degree of polymerization is within the above range, the effects of the present invention can be fully exhibited.

[0044] Examples of polyvinyl alcohols that can be used in the present invention include "PVA-117" (degree of polymerization 1,700, degree of saponification 98 to 99 mol%), "PVA-117H" (degree of polymerization 1,700, degree of saponification 99.3 mol% or more), and "PVA-124" (degree of polymerization 2,400, degree of saponification 98 to 99 mol%), all of which are sold in powder form and are manufactured by Kuraray Co., Ltd.

[0045] The lower limit of the polyvinyl alcohol content in the first liquid is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, relative to the total mass of the first liquid. The upper limit of the polyvinyl alcohol content in the first liquid is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. That is, the polyvinyl alcohol content is preferably 0.05 to 10% by mass, more preferably 0.1 to 7% by mass, and even more preferably 0.5 to 5% by mass. When the polyvinyl alcohol content is within the above range, the effects of the present invention are fully exhibited.

[0046] (water) Water serves as a solvent for polyvinyl alcohol. It is preferable that the water contains as few impurities as possible. It is preferable that the water be water from which impurity ions have been removed using an ion exchange resin, impurities have been removed using a filter, or foreign matter has been removed by distillation. Examples of such water include ion-exchanged water, pure water, ultrapure water, and distilled water. To minimize the inhibition of the functions of the semiconductor wetting agent and / or other components contained in the polishing composition, it is preferable that the total content of transition metal ions is 100 ppb or less.

[0047] The water content is preferably 90% by mass or more, more preferably 93% by mass or more, and even more preferably 95% by mass or more, based on the total mass of the first liquid. The upper limit of the water content is preferably 99.95% by mass or less, more preferably 99.9% by mass or less, and even more preferably 99.5% by mass or less, based on the total mass of the first liquid. That is, the water content is preferably 90 to 99.95% by mass, more preferably 93 to 99.9% by mass, and even more preferably 95 to 99.5% by mass, based on the total mass of the first liquid. When the water content is within the above range, the effects of the present invention are fully exhibited.

[0048] (Method for preparing the first liquid) The method for preparing the first liquid having the above-described composition is not particularly limited, and examples thereof include a method including the following steps A and B: Step A: a dispersing step of dispersing polyvinyl alcohol in water to obtain a polyvinyl alcohol dispersion; Step B: A dissolving step in which the polyvinyl alcohol dispersion is heated to 80°C or higher and stirred to dissolve the polyvinyl alcohol in water to obtain a first liquid.

[0049] ·Process A: Dispersion process The temperature of the water when dispersing polyvinyl alcohol in water is preferably 15° C. or higher, more preferably 20° C. or higher. The temperature of the water when dispersing polyvinyl alcohol in water is preferably 25° C. or lower. When the water temperature is within the above range, the polyvinyl alcohol is preferably prevented from forming clumps in the water.

[0050] The content of polyvinyl alcohol in the polyvinyl alcohol dispersion is the same as the content of polyvinyl alcohol in the first liquid obtained through the dissolving step after the dispersing step. If the content of polyvinyl alcohol is within the above range, the polyvinyl alcohol dispersion can be prepared efficiently, which is preferable.

[0051] When dispersing polyvinyl alcohol in water, it is preferable to carry out stirring. For example, the dispersion step is preferably carried out in a stirring vessel equipped with a stirrer.

[0052] The dispersion step is preferably completed when the polyvinyl alcohol is uniformly dispersed, and the next step, the dissolution step, is started.

[0053] ·Process B: Melting process As used herein, the dissolving step refers to a period during which the temperature of water exceeds 80°C when polyvinyl alcohol is dissolved in water. The temperature of water when polyvinyl alcohol is dissolved in water is preferably 85°C or higher, more preferably 88°C or higher, and even more preferably 90°C or higher. Furthermore, the temperature of water when polyvinyl alcohol is dissolved in water is preferably 98°C or lower, more preferably 96°C or lower, and even more preferably 94°C or lower. When the water temperature is within the above range, polyvinyl alcohol dissolves sufficiently in water, and a uniform aqueous polyvinyl alcohol solution (first liquid) can be obtained, which is preferable.

[0054] The content of polyvinyl alcohol in the first liquid obtained through the dissolving step is as described above.

[0055] When dissolving polyvinyl alcohol in water, stirring is preferably performed. The stirring time (i.e., the time required to dissolve polyvinyl alcohol in water) is preferably 10 minutes or more, more preferably 20 minutes or more. The stirring time is preferably 300 minutes or less, more preferably 200 minutes or less, and even more preferably 100 minutes or less. For example, the stirring time can be 80 minutes or less, 60 minutes or less, or 30 minutes or less.

[0056] The dissolving step is completed when the polyvinyl alcohol is uniformly dissolved, and the obtained first liquid is preferably cooled to 15 to 50°C (preferably 20 to 35°C, e.g., 25 to 28°C) before proceeding to the next step. Cooling may be performed by either cooling using a device or cooling by natural heat dissipation. In addition, either air cooling or liquid cooling (e.g., water cooling) may be used, and the type of heat exchange medium is not important.

[0057] According to one embodiment of the present invention, it is preferable to prepare the first liquid through steps A and B. Therefore, according to a preferred embodiment of the present invention, the first liquid is obtained by heating a polyvinyl alcohol dispersion in which polyvinyl alcohol is dispersed in water to 85 to 98°C and then cooling it to 15 to 50°C. This makes it easier for polyvinyl alcohol to be uniformly dissolved in the first liquid, and as a result, a polyvinyl alcohol composition with reduced generation of aggregates can be obtained.

[0058] (additives) As described above, the first liquid may contain known additives. The additives are not particularly limited, but are preferably added after dissolving polyvinyl alcohol in water.

[0059] [Second liquid] The second liquid contains a solvent. The second liquid may further contain known additives such as abrasive grains, surfactants, water-soluble polymers, thickeners, pH adjusters, complexing agents, preservatives, and antifungal agents, as needed. Here, the second liquid may be, for example, a solvent alone, or a solution containing polyvinyl alcohol and a solvent. Thus, according to one embodiment of the present invention, the second liquid may be a mixture of a first liquid containing polyvinyl alcohol and water (the second liquid), or a mixture of a first liquid containing polyvinyl alcohol and a second liquid containing polyvinyl alcohol.

[0060] The second liquid may contain polyvinyl alcohol. In this case, the second liquid contains a solvent and polyvinyl alcohol. When the second liquid contains polyvinyl alcohol, the lower limit of the content of polyvinyl alcohol in the second liquid is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, relative to the total mass of the second liquid. Furthermore, the upper limit of the content of polyvinyl alcohol in the second liquid is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less.

[0061] The second liquid may contain abrasive grains. In this case, the second liquid contains a solvent and abrasive grains. When the second liquid contains abrasive grains, the lower limit of the abrasive grain content in the second liquid is preferably 0.5 mass % or more, more preferably 1 mass % or more, and even more preferably 5 mass % or more, based on the total mass of the second liquid. Furthermore, the upper limit of the abrasive grain content in the second liquid is preferably 80 mass % or less, more preferably 75 mass % or less, and even more preferably 60 mass % or less.

[0062] (solvent) Examples of the solvent contained in the second liquid include water; alcohols such as methanol, ethanol, and ethylene glycol; ketones such as acetone; and mixtures thereof. Of these, water is preferred as the solvent. That is, according to a preferred embodiment of the present invention, the solvent in the second liquid contains water. According to a more preferred embodiment of the present invention, the solvent in the second liquid consists essentially of water. Note that the above term "substantially" means that a solvent other than water may be contained as long as the intended effect of the present invention can be achieved. More specifically, the second liquid preferably consists of 90% by mass to 100% by mass of water and 0% by mass to 10% by mass of a solvent other than water, and more preferably 99% by mass to 100% by mass of water and 0% by mass to 1% by mass of a solvent other than water. Most preferably, the solvent is water.

[0063] When a polyvinyl alcohol composition is used in a semiconductor wetting agent and / or polishing composition, from the viewpoint of not inhibiting the action of the components contained in the semiconductor wetting agent and / or polishing composition, the solvent used in the second liquid is preferably water containing as few impurities as possible.Specifically, pure water or ultrapure water from which impurity ions have been removed using an ion exchange resin and then foreign matter has been removed through a filter, or distilled water is more preferred.

[0064] The content of the solvent is preferably 90% by mass or more, more preferably 93% by mass or more, and even more preferably 95% by mass or more, based on the total mass of the second liquid. The upper limit of the content of the solvent is preferably 100% by mass or less, more preferably 99.9% by mass or less, and even more preferably 99.5% by mass or less, based on the total mass of the second liquid. That is, the content of the solvent is preferably 90 to 100% by mass, more preferably 93 to 99.9% by mass, and even more preferably 95 to 99.5% by mass, based on the total mass of the second liquid.

[0065] [In-liquid addition process] In the present invention, the mixing step of mixing a first liquid containing polyvinyl alcohol and water with a second liquid other than the first liquid to obtain a polyvinyl alcohol composition includes a submerged addition step of submergedly adding either the first liquid or the second liquid into a solution of either the first liquid or the second liquid. That is, the production method of the present invention is characterized in that the mixing step of mixing the first liquid and the second liquid includes a submerged addition step of submergedly adding either the first liquid or the second liquid into either the first liquid or the second liquid.

[0066] In the submerged addition step, the second liquid may be submerged added to the first liquid, or the first liquid may be submerged added to the second liquid. The method of submerged addition is not particularly limited, and examples include a method in which the addition is performed through a supply pipe. Specifically, one end of the supply pipe is placed in one of the first liquid or the second liquid, which is the supply side, and the other end of the supply pipe is placed in the other of the first liquid or the second liquid, which is the supply side. Then, using a pump such as an air pump, one of the first liquid or the second liquid, which is the supply side, is added through the supply pipe to the other of the first liquid or the second liquid, which is the supply side.

[0067] According to one embodiment of the present invention, it is preferable to submergedly add the first liquid into the second liquid, which allows the polyvinyl alcohol in the first liquid to mix with the second liquid without coming into contact with air, thereby further suppressing the generation of polyvinyl alcohol lumps.

[0068] In this case, the size of the supply pipe is not particularly limited, but a diameter of 50 cm or less is preferable. With such a supply pipe, there is no effect on the liquid surface, and submerged addition can be carried out efficiently.

[0069] The supply speed for the submerged addition is not particularly limited, but is preferably slow enough to prevent the formation of lumps due to collisions between polyvinyl alcohol molecules. A supply speed of 50 mL / min or more is preferred, more preferably 100 mL / min or more, and even more preferably 120 mL / min or more is preferred. Furthermore, the supply speed for the submerged addition is preferably 20 L / min or less. At such a supply speed, the submerged addition can be carried out efficiently without affecting the liquid surface.

[0070] The other of the first liquid and the second liquid to be supplied is preferably held in a vessel having a stirring means. This allows stirring while the submerged addition is being carried out. According to one embodiment of the present invention, the first liquid is submerged added to the second liquid held in a vessel having a stirring means. Here, examples of the vessel having a stirring means include a vertical stirring vessel and a horizontal stirring vessel.

[0071] A vertical stirring vessel is a vessel equipped with a vertical rotation shaft and stirring blades attached to the vertical rotation shaft. Examples of the type of stirring blade include propeller blades, turbine blades, paddle blades, Pfaudle blades, anchor blades, Fullzone (registered trademark) blades (manufactured by Kobe Steel Pantech Co., Ltd.), Sun-Meller blades (manufactured by Mitsubishi Heavy Industries, Ltd.), Maxblend (registered trademark) blades (manufactured by Sumitomo Heavy Industries, Ltd.), helical ribbon blades, and twisted lattice blades (manufactured by Hitachi, Ltd.).

[0072] A horizontal stirring vessel has multiple impellers installed inside, each with a horizontal (horizontal) rotation axis and multiple impellers extending almost perpendicular to the axis, with the impellers on each horizontal rotation axis offset from each other in the horizontal direction so as not to collide. Examples of impeller types include single-shaft impellers such as disc and paddle types, and double-shaft impellers such as spectacle and lattice impellers (manufactured by Hitachi, Ltd.). Other examples include wheel-, paddle-, rod-, and window-frame-type impellers.

[0073] The size of the stirring vessel is not particularly limited, and is preferably 0.01 m 3 At least 0.1m, preferably 0.1m 3 More than 1m, more preferably 1m 3 The size of the stirring vessel is preferably 20 m or more. 3 Less than or equal to 10m, preferably 3 The following is the result.

[0074] The material of the stirring vessel is not particularly limited. For example, a vessel made of stainless steel is preferred, and a vessel whose inner wall is coated with SUS316, glass, Teflon, titanium, or the like is more preferred. The stirring vessel can be equipped with baffles as needed. The size, shape, and number of baffles are not particularly limited.

[0075] The strength and size of the rotating shaft are not particularly limited, and the material of the rotating shaft is also not limited, but for example, stainless steel is preferable, and glass, Teflon, or titanium coated shafts, or SUS316 stainless steel are more preferable.

[0076] The number of stirring blades used is not particularly limited, and can be, for example, 1 to 10, preferably 1 to 5, and more preferably 2 to 5. When three or more stirring blades are used, the spacing between the stirring blades at multiple locations is not limited, but it is preferable to arrange them evenly.

[0077] The size of the impeller is not limited. For example, the ratio (L / D) of the impeller diameter (L) to the inner diameter (D) of the stirred vessel can be preferably 0.1 or more, more preferably 0.25 or more. Furthermore, L / D can be preferably 0.9 or less, more preferably 0.75 or less. The "inner diameter of the stirred vessel" refers to the longest diameter perpendicular to the rotation axis inside the stirred vessel. For example, when using a stirred vessel consisting of a cylindrical portion sandwiched between upper and lower mirror sections (the rounded upper and lower sections of the stirred vessel), this refers to the diameter of the cylindrical portion inside the vessel. The "stirring blade diameter" refers to the diameter obtained by doubling the longest distance from the center of the rotation axis to the tip of the impeller. The "tip of the impeller" refers to the farthest part when measured perpendicular to the rotation axis.

[0078] In the submerged addition step, adjacent stirring blades may form any angle when viewed in the axial direction. From the viewpoint of efficient stirring, an angle of 0 degrees (parallel) or 90 degrees (right angle) is preferred.

[0079] The material of the stirring blade is not particularly limited, and is preferably made of stainless steel, more preferably coated with glass, Teflon, or titanium, or made of SUS316 stainless steel.

[0080] The atmosphere in the stirring vessel during stirring is not particularly limited, and examples thereof include an air atmosphere and an inert gas atmosphere such as argon or nitrogen, and stirring can be carried out under normal pressure or reduced pressure conditions.

[0081] The temperature of the solution during the submerged addition step is preferably 20°C or higher, more preferably 25°C or higher. The temperature of the solution during the submerged addition step is preferably 80°C or lower, more preferably 60°C or lower. Methods for heating the stirring vessel include a method in which a heat medium jacket is installed on the outer periphery of the stirring vessel and the solution is heated by heat transfer through the wall of the stirring vessel, and a method in which the solution is heated by heat transfer through a heat transfer tube (coil) inside the stirring vessel, and the like. These methods may be used alone or in combination.

[0082] In the submerged addition step, the rotation speed of the impeller in the stirring vessel on the supply side (i.e., the stirring speed) is not particularly limited. Stirring may or may not be performed. When stirring is performed, the rotation speed is preferably 1 rpm or more, although it depends on the capacity of the stirring vessel. From the viewpoint of suppressing the generation of polyvinyl alcohol lumps, the rotation speed of the impeller is preferably 300 rpm or less, more preferably 200 rpm or less, and even more preferably 100 rpm or less. That is, when stirring is performed in the submerged addition step, the rotation speed of the impeller is preferably 1 rpm or more and 300 rpm or less, more preferably 1 rpm or more and 200 rpm or less, and even more preferably 1 rpm or more and 100 rpm or less. When the rotation speed of the impeller is within the above range, the rotational vortex caused by stirring does not become too large, and gas entrapment is reduced.

[0083] The time for the submerged addition step depends on the amount of solution on the supply side (addition side), but it is preferable to complete the addition within, for example, 1 to 30 minutes.

[0084] Here, the mixing ratio of the first liquid to the second liquid is preferably 1:99 to 99:1 by mass, more preferably 10:90 to 90:10, even more preferably 20:80 to 80:20, and particularly preferably 30:70 to 70:30. The mass ratio can be, for example, 20:80 to 40:60, or 80:20 to 60:40.

[0085] The content of polyvinyl alcohol in the polyvinyl alcohol composition obtained in the liquid addition step is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, based on the total mass of the polyvinyl alcohol composition. The upper limit of the content of polyvinyl alcohol in the polyvinyl alcohol composition obtained in the liquid addition step is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. When the content of polyvinyl alcohol in the polyvinyl alcohol composition obtained in the liquid addition step is within the above range, the generation of aggregates can be suppressed, and the effects of the present invention can be more effectively achieved.

[0086] [Process after the liquid addition process] ·Process C: Stirring process According to one embodiment of the present invention, the method includes a stirring step of stirring the polyvinyl alcohol composition after the submerged adding step. By performing the stirring step, the polyvinyl alcohol is preferably uniformly dispersed.

[0087] The temperature of the polyvinyl alcohol composition during the stirring step is preferably 20° C. or higher, more preferably 30° C. or higher. The temperature of the polyvinyl alcohol composition during the stirring step is preferably 80° C. or lower, more preferably 60° C. or lower.

[0088] In the stirring step, the rotation speed of the stirring blade in the stirring vessel (i.e., the stirring speed) depends on the volume of the stirring vessel, but is preferably 1 rpm or more. Furthermore, from the viewpoint of suppressing the generation of polyvinyl alcohol lumps, the rotation speed of the stirring blade is preferably 300 rpm or less, more preferably 200 rpm or less, and even more preferably 100 rpm or less. That is, the rotation speed of the stirring blade in the stirring step after the submerged addition step is preferably 1 rpm or more and 300 rpm or less, more preferably 1 rpm or more and 200 rpm or less, and even more preferably 1 rpm or more and 100 rpm or less. If the rotation speed of the stirring blade is within the above range, the rotational vortex caused by stirring will not become too large, and gas entrapment will be reduced.

[0089] The size of the stirring blade is not limited, and for example, the ratio (L / D) of the stirring blade diameter (L) to the stirring vessel inner diameter (D) can be set to preferably 0.1 or more, more preferably 0.25 or more, and L / D can be set to preferably 0.9 or less, more preferably 0.75 or less.

[0090] The stirring step can be terminated when the polyvinyl alcohol is uniformly dispersed, and the stirring time in the stirring step is preferably 1 minute or more, more preferably 2 minutes or more, and even more preferably 3 minutes or more, and is preferably 45 minutes or less, more preferably 30 minutes or less, and even more preferably 10 minutes or less.

[0091] ·Process D: Filtration process The filtration step is a step of filtering the polyvinyl alcohol composition after preparation. This step allows for the removal of aggregates in the polyvinyl alcohol composition. According to one embodiment of the present invention, the method further includes a filtration step of filtering the polyvinyl alcohol composition obtained through the addition step.

[0092] The content of polyvinyl alcohol in the polyvinyl alcohol composition used in the filtration step is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass. The content of polyvinyl alcohol in the polyvinyl alcohol composition is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. When the content of polyvinyl alcohol is within the above range, the viscosity of the polyvinyl alcohol composition does not become excessively high, and a high filtration rate can be obtained, which is preferable.

[0093] The filter medium used for filtering the polyvinyl alcohol composition is not particularly limited, but examples include polypropylene, polystyrene (PS), polyethersulfone, nylon, nylon 66, cellulose, cellulose mixed esters, cellulose acetate, nitrocellulose, regenerated cellulose, polytetrafluoroethylene (PTFE), polycarbonate, glass, polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer, polyamide, triacetyl cellulose, polyvinyl chloride (PVC), polysulfone, polyester, polypropylene / polyethylene, acrylic copolymer, polylactic acid, polycaprolactone, polyglycolic acid, polydioxanone, polyhydroxybutyrate, polybutadiene, polyurethane, polymethyl methacrylate, and metal.

[0094] The filter structure is not particularly limited, but examples thereof include a depth structure, a pleated structure, and a membrane structure.

[0095] The pore size of the filter is not particularly limited, but is preferably 0.03 μm or more, more preferably 0.04 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more. A filter pore size of 0.03 μm or more is preferable because a high filtration rate can be obtained. Furthermore, the pore size of the filter is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less. The pore size of the filter may be 20 μm or less, 10 μm or less, 5 μm or less, or 1 μm or less. A filter pore size of 100 μm or less is preferable because the filtration accuracy is improved.

[0096] The filtration method may be any of natural filtration under normal pressure, suction filtration, pressure filtration, and centrifugal filtration.

[0097] The filtration step may be performed two or more times. In this case, it is preferable to appropriately change the conditions such as the pore size of the filter. For example, in the first dissolution filtration, a filter with a large pore size is used to remove coarse particles, and in the second dissolution filtration, a filter with a small pore size is used to remove fine particles. By performing the dissolution filtration two or more times, it is possible to remove impurities more efficiently.

[0098] Step E: Alkali addition step According to one embodiment of the present invention, the method further includes an alkali addition step of adding an alkali to the polyvinyl alcohol composition obtained through the liquid addition step. By performing the alkali addition step, the polyvinyl alcohol composition can be suitably used as a polishing composition and / or a wetting agent for semiconductors, which will be described later. Details of the alkali addition step will be described in the section on the polishing composition and / or the wetting agent for semiconductors.

[0099] [Polyvinyl alcohol composition] According to one embodiment of the present invention, there is provided a polyvinyl alcohol composition containing polyvinyl alcohol. The polyvinyl alcohol composition contains a first liquid and a second liquid, thereby containing at least polyvinyl alcohol and water. The polyvinyl alcohol composition may further contain a solvent other than water, if necessary. Furthermore, the polyvinyl alcohol composition may contain abrasive grains, if necessary.

[0100] The content of polyvinyl alcohol in the polyvinyl alcohol composition is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, and particularly preferably 0.005% by mass or more, relative to the total mass of the polyvinyl alcohol composition. The content can be, for example, 0.01% by mass or more, 0.1% by mass or more, or 0.4% by mass or more. Furthermore, the content of polyvinyl alcohol is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, relative to the total mass of the polyvinyl alcohol composition. The content can be, for example, 2% by mass or less, 1.5% by mass or less, or 0.9% by mass or less.

[0101] The polyvinyl alcohol composition obtained by the production method of the present invention is suppressed in the generation of aggregates and has excellent filterability, making the polyvinyl alcohol composition suitable for use as a wetting agent for semiconductors and / or a polishing composition.

[0102] The polyvinyl alcohol composition of the present invention may further contain known additives such as surfactants, water-soluble polymers other than polyvinyl alcohol, chelating agents, organic acids, organic acid salts, inorganic acids, inorganic acid salts, pH adjusters, oxidizing agents, metal corrosion inhibitors, preservatives, and antifungal agents. The additives contained in the polyvinyl alcohol composition may be added to at least one of the first liquid and the second liquid, thereby adding the additives to the polyvinyl alcohol composition. Alternatively, the additives may be added to the polyvinyl alcohol composition via a solution other than the first liquid and the second liquid, or may be added directly to the polyvinyl alcohol composition.

[0103] <Wetting agent for semiconductor and polishing composition> The polyvinyl alcohol composition obtained by the production method of the present invention can be used in various applications, such as adhesives, binders for pharmaceuticals, dispersants, films, cosmetics, textile raw materials, glues, paints, emulsifiers, packaging, polishing and post-polishing rinsing agents, etc. Among these, its use in polishing and post-polishing rinsing agents is preferred.

[0104] According to one aspect of the present invention, there is provided a semiconductor wetting agent and / or polishing composition containing a polyvinyl alcohol composition produced by the production method of the present invention. That is, according to one embodiment of the present invention, there is provided a method for producing a semiconductor wetting agent and / or polishing composition containing a polyvinyl alcohol composition, wherein the polyvinyl alcohol composition is obtained by submerged addition of either a first liquid containing polyvinyl alcohol and water or a second liquid other than the first liquid to either the first liquid or the second liquid. The semiconductor wetting agent according to this aspect comprises a polyvinyl alcohol composition. The polyvinyl alcohol composition produced by the production method of the present invention is suitable for use as a semiconductor wetting agent and therefore may be a polyvinyl alcohol composition for use as a semiconductor wetting agent. Furthermore, the polishing composition according to this aspect comprises a polyvinyl alcohol composition. The polyvinyl alcohol composition produced by the production method of the present invention is suitable for use as a polishing composition and therefore may be a polyvinyl alcohol composition for use as a polishing composition. If necessary, the semiconductor wetting agent and / or polishing composition according to this aspect may contain other additives, such as a pH adjuster.

[0105] The wetting agent for semiconductors according to this embodiment may be composed only of the polyvinyl alcohol composition. That is, according to one embodiment, the polyvinyl alcohol composition produced by the production method of the present invention is a wetting agent for semiconductors.

[0106] Furthermore, the wetting agent for semiconductors may be a polyvinyl alcohol composition produced by the production method of the present invention diluted with, for example, water. Thus, according to one aspect of the present invention, there is provided a wetting agent for semiconductors comprising the polyvinyl alcohol composition produced by the production method of the present invention and a third liquid containing water. That is, according to one aspect of the present invention, there is also provided a method for producing a wetting agent for semiconductors, comprising mixing the polyvinyl alcohol composition produced by the production method of the present invention with a third liquid containing water.

[0107] The third liquid contains water. The third liquid may further contain known additives such as surfactants, water-soluble polymers, thickeners, pH adjusters (preferably alkalis), complexing agents, preservatives, and antifungal agents, as needed. Here, the third liquid may consist of, for example, only water, or may further contain a solvent. Examples of the solvent contained in the third liquid include alcohols such as methanol, ethanol, and ethylene glycol; ketones such as acetone; and mixtures thereof. According to a more preferred embodiment of the present invention, the solvent in the third liquid consists essentially of water. Note that the term "substantially" above has the same meaning as that of the second liquid.

[0108] Here, when the polyvinyl alcohol composition and the third liquid are mixed to produce a wetting agent for semiconductors, the same method as the method for producing the polyvinyl alcohol composition described above is preferably used.That is, when the polyvinyl alcohol composition and the third liquid are mixed to produce a wetting agent for semiconductors, a preferred embodiment includes a submerged addition step of adding either the polyvinyl alcohol composition or the third liquid into either one of the polyvinyl alcohol composition and the third liquid.

[0109] In the wetting agent for semiconductors, the mass ratio of the polyvinyl alcohol composition to the third liquid (polyvinyl alcohol composition:third liquid) is not particularly limited and can be, for example, 10:90 to 90:10, 15:75 to 75:15, or 20:80 to 80:20.

[0110] According to one aspect of the present invention, there is provided a polishing composition comprising a semiconductor wetting agent containing a polyvinyl alcohol composition produced by the production method of the present invention and abrasive grains. The polishing composition according to this aspect comprises a semiconductor wetting agent containing a polyvinyl alcohol composition and abrasive grains. If necessary, the polishing composition according to this aspect may also contain other additives such as a pH adjuster.

[0111] Furthermore, according to one aspect of the present invention, there is provided a method for producing a polishing composition, which comprises mixing a wetting agent for semiconductors containing a polyvinyl alcohol composition produced by the production method of the present invention with abrasive grains.

[0112] Polyvinyl alcohol has hydroxyl groups (OH groups) in its molecules. Therefore, polyvinyl alcohol has a tendency to aggregate due to the action of intramolecular or intermolecular hydrogen bonds. If a portion of the polyvinyl alcohol contained in the polishing composition and / or semiconductor wetting agent aggregates to form clumps, reducing dispersibility, the ability to reduce surface defects after polishing or rinsing may be reduced. The technology disclosed herein can provide a polishing composition and / or semiconductor wetting agent with improved dispersibility by appropriately suppressing the formation of clumps of polyvinyl alcohol.

[0113] The following describes the preferred form of the semiconductor wetting agent and / or polishing composition of the present invention. It should be noted that matters other than those specifically mentioned in this specification that are necessary for carrying out the present invention can be understood as design matters for those skilled in the art based on the prior art in the relevant field. The present invention can be carried out based on the contents disclosed in this specification and the technical common sense in the relevant field.

[0114] (Polyvinyl alcohol composition) The wetting agent and / or polishing composition for semiconductors disclosed herein includes a polyvinyl alcohol composition produced by the production method of the present invention.

[0115] The concentration (pure content) of polyvinyl alcohol in the semiconductor wetting agent and / or polishing composition is not particularly limited, and can be, for example, 0.0001% by weight or more.From the viewpoint of haze reduction, etc., the preferred concentration is 0.0005% by weight or more, more preferably 0.001% by weight or more, for example, 0.003% by weight or more, and may be 0.005% by weight or more.In addition, from the viewpoint of the action on the substrate, etc., the concentration (pure content) of polyvinyl alcohol is usually preferably 0.5% by weight or less, may be 0.2% by weight or less, or may be 0.1% by weight or less.

[0116] (abrasive grain) The polishing composition disclosed herein contains abrasive grains. The abrasive grains mechanically polish the surface of the object to be polished. The material and properties of the abrasive grains are not particularly limited and can be appropriately selected depending on the intended use and manner of use of the polishing composition. Examples of abrasive grains include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include oxide particles such as silica particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and red iron oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; carbonates such as calcium carbonate and barium carbonate; and the like. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles (here, (meth)acrylic acid refers collectively to acrylic acid and methacrylic acid), polyacrylonitrile particles, and the like. Such abrasive grains may be used alone or in combination of two or more. The abrasive grains may be synthetic or commercially available. The wetting agent for semiconductors does not include abrasive grains.

[0117] The abrasive grains are preferably inorganic particles, and among these, particles made of metal or semi-metal oxides are preferred, with silica particles being particularly preferred. In polishing compositions that can be used for polishing (e.g., finish polishing) substrates having a silicon surface, such as silicon wafers, described below, it is particularly meaningful to employ silica particles as the abrasive grains. The technology disclosed herein can be preferably implemented, for example, in an embodiment in which the abrasive grains are essentially made of silica particles. Here, "substantially" means that 95% by weight or more (preferably 98% by weight or more, more preferably 99% by weight or more, and even 100% by weight) of the particles constituting the abrasive grains are silica particles.

[0118] Specific examples of silica particles include colloidal silica, fumed silica, precipitated silica, etc. Silica particles can be used alone or in combination of two or more types. Colloidal silica is particularly preferred because it is easy to obtain a polished surface with excellent surface quality after polishing. As colloidal silica, for example, colloidal silica produced by an ion exchange method using water glass (sodium silicate) as a raw material, or alkoxide method colloidal silica (colloidal silica produced by the hydrolysis and condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used alone or in combination of two or more types.

[0119] The abrasive grains may also be surface-modified. Specifically, the silica particles may have cationic groups. That is, the silica particles may be cation-modified silica particles or cation-modified colloidal silica. Colloidal silica having cationic groups (cation-modified colloidal silica) is preferably colloidal silica having amino groups fixed to its surface. Examples of methods for producing colloidal silica having cationic groups include those described in JP 2005-162533 A, in which a silane coupling agent having an amino group, such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, or aminobutyltriethoxysilane, is fixed to the surface of silica particles. This method allows for the production of colloidal silica having amino groups fixed to its surface (amino-group-modified colloidal silica).

[0120] The silica particles may have anionic groups. That is, the silica particles may be anion-modified silica particles or anion-modified colloidal silica. As colloidal silica having anionic groups (anion-modified colloidal silica), colloidal silica having anionic groups such as carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, and aluminic acid groups fixed to the surface is preferably used. The method for producing such colloidal silica having anionic groups is not particularly limited, and examples thereof include a method of reacting colloidal silica with a silane coupling agent having an anionic group at its terminal.

[0121] As a specific example, sulfonic acid groups can be immobilized on colloidal silica by the method described in "Sulfonic acid-functionalized silica through thiol groups," Chem. Commun. 246-247 (2003). Specifically, a silane coupling agent having a thiol group, such as 3-mercaptopropyltrimethoxysilane, is coupled to colloidal silica, and then the thiol group is oxidized with hydrogen peroxide to obtain colloidal silica with sulfonic acid groups immobilized on the surface (sulfonic acid-modified colloidal silica).

[0122] Carboxylic acid groups can be immobilized on colloidal silica by, for example, the method described in "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel," Chemistry Letters, 3, 228-229 (2000). Specifically, colloidal silica with carboxylic acid groups immobilized on the surface (carboxylic acid-modified colloidal silica) can be obtained by coupling a silane coupling agent containing a photolabile 2-nitrobenzyl ester to colloidal silica and then irradiating it with light.

[0123] The true specific gravity of the abrasive grain constituent material (e.g., silica constituting silica particles) is preferably 1.5 or more, more preferably 1.6 or more, and even more preferably 1.7 or more. The upper limit of the true specific gravity of silica is not particularly limited, but is typically 2.3 or less, for example, 2.2 or less. The true specific gravity of the abrasive grain (e.g., silica particles) can be measured by a liquid displacement method using ethanol as the displacement liquid.

[0124] The BET diameter of the abrasive grains (typically silica particles) is not particularly limited, but from the viewpoint of polishing efficiency, etc., it is preferably 5 nm or more, more preferably 10 nm or more. From the viewpoint of obtaining a higher polishing effect (e.g., effects such as haze reduction and defect removal), the BET diameter is preferably 15 nm or more, more preferably 20 nm or more (e.g., more than 20 nm). Furthermore, from the viewpoint of scratch prevention, etc., the BET diameter of the abrasive grains is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 40 nm or less. Since the technology disclosed herein is likely to produce a high-quality surface (e.g., a surface with a low LPD number), it is preferably applied to polishing that requires a high-quality surface after polishing. The abrasive grains used in such a polishing composition are preferably abrasive grains with a BET diameter of 35 nm or less (typically less than 35 nm, more preferably less than 32 nm, e.g., less than 30 nm).

[0125] In this specification, the BET diameter is calculated from the specific surface area (BET value) measured by the BET method, as follows: BET diameter (nm) = 6000 / (true density (g / cm 3 )×BET value(m 2 / g)). For example, in the case of silica particles, BET diameter (nm) = 2727 / BET value (m 2 The BET diameter can be calculated from the specific surface area (ratio of specific surface area to particle diameter) and the specific surface area (g / g). The specific surface area can be measured using, for example, a surface area measuring device manufactured by Micromeritics, product name "Flow Sorb II 2300".

[0126] The average secondary particle diameter of the abrasive grains is not particularly limited, but from the viewpoint of polishing efficiency, etc., it is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, and particularly preferably 25 nm or more. From the viewpoint of obtaining a higher polishing effect, such as haze reduction and defect removal, the average secondary particle diameter is preferably 30 nm or more, more preferably 40 nm or more. Furthermore, from the viewpoint of suppressing local stress applied by the abrasive grains to the substrate surface, the average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and even more preferably 125 nm or less. The technology disclosed herein is also preferably in an embodiment using abrasive grains with an average secondary particle diameter of 100 nm or less, for example, less than 80 nm (typically 45 nm or less), because a higher-quality surface is more likely to be obtained. The reduction in the average secondary particle diameter of the abrasive grains that can be implemented improves the stability of the polishing composition. The average secondary particle size of the abrasive grains can be measured by dynamic light scattering using, for example, a model "UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0127] The shape (external shape) of the abrasive grains may be spherical or non-spherical. Specific examples of non-spherical particles include peanut-shaped (i.e., peanut shell-shaped), cocoon-shaped, confetti-shaped, and rugby ball-shaped. For example, abrasive grains in which most of the particles are peanut-shaped or cocoon-shaped can be preferably used.

[0128] Although not particularly limited, the average value of the ratio of the major axis to the minor axis of the abrasive grains (average aspect ratio) is, in principle, 1.0 or more, preferably 1.05 or more, and more preferably 1.1 or more. By increasing the average aspect ratio, higher polishing efficiency can be achieved. Furthermore, from the viewpoint of reducing scratches, etc., the average aspect ratio of the abrasive grains is preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.5 or less.

[0129] The shape (outline) and average aspect ratio of abrasive grains can be determined, for example, by observation using an electron microscope. A specific procedure for determining the average aspect ratio involves, for example, using a scanning electron microscope (SEM), drawing the smallest rectangle circumscribing each particle image for a predetermined number (e.g., 200) of abrasive grains whose individual particle shapes can be recognized. Then, for each rectangle drawn for each particle image, the long side length (long diameter value) is divided by the short side length (short diameter value) to calculate the long diameter / short diameter ratio (aspect ratio). The average aspect ratio can be determined by arithmetically averaging the aspect ratios of the predetermined number of particles.

[0130] The content of abrasive grains in the polishing composition is not particularly limited, but is typically 0.01 wt% or more, preferably 0.05 wt% or more, more preferably 0.10 wt% or more, for example, 0.15 wt% or more. By increasing the content of abrasive grains, a higher polishing rate can be achieved. From the viewpoint of dispersion stability of the abrasive grains in the polishing composition, the content is usually 10 wt% or less, preferably 7 wt% or less, more preferably 5 wt% or less, even more preferably 2 wt% or less, for example, 1 wt% or less, and may be 0.7 wt% or less. In a preferred embodiment, the content may be 0.5 wt% or less, 0.4 wt% or less, or 0.2 wt% or less.

[0131] (surfactant) The polishing composition and / or semiconductor wetting agent disclosed herein may contain a surfactant to the extent that the effects of the present invention are not significantly impaired. Any of anionic, cationic, nonionic, and amphoteric surfactants can be used as the surfactant. The polishing composition and / or semiconductor wetting agent disclosed herein can be implemented in an embodiment that is substantially free of surfactants.

[0132] Anionic surfactants are classified into, for example, sulfates, sulfonic acids, phosphoric acids, phosphonic acids, and carboxylic acids. Specific examples of anionic surfactants include alkyl sulfates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl sulfates, alkyl sulfates, alkyl ether sulfates, higher alcohol sulfates, alkyl phosphates, alkylbenzene sulfonic acids, α-olefin sulfonic acids, alkyl sulfonic acids, styrene sulfonic acids, alkyl naphthalene sulfonic acids, alkyl diphenyl ether disulfonic acids, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether phosphoric acids, polyoxyethylene alkyl phosphates, polyoxyethylene sulfosuccinic acids, alkyl sulfosuccinic acids, and salts thereof, taurine surfactants, sarcosinate surfactants, isethionate surfactants, N-acyl acidic amino acid surfactants, higher fatty acid salts, and acylated polypeptides. Specific examples of alkyl sulfonic acids or their salts include dodecyl sulfonic acid and dodecyl sulfonate salts.

[0133] Cationic surfactants are classified into, for example, polyoxyethylene alkylamines, alkyl alkanolamides, alkylamine salts, amine oxides, quaternary ammonium salts, and tertiary amidoamine surfactants. Specific examples of cationic surfactants include coconut amine acetate, stearyl amine acetate, lauryl dimethyl amine oxide, stearic acid dimethylaminopropylamide, alkyl trimethyl ammonium salts, alkyl dimethyl ammonium salts, and alkyl benzyl dimethyl ammonium salts.

[0134] Specific examples of amphoteric surfactants include alkyl betaines, alkylamine oxides, etc. Specific examples of amphoteric surfactants include cocobetaine, lauramidopropyl betaine, cocamidopropyl betaine, sodium lauroamphoacetate, sodium cocoamphoacetate, coconut oil fatty acid amidopropyl betaine, lauryl betaine (lauryl dimethylaminoacetic acid betaine), etc.

[0135] Specific examples of nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives (e.g., polyoxyalkylene adducts) such as polyoxyethylene alkyl ethers, polyoxyethylene alkylamines, polyoxyalkylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; copolymers of multiple types of oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers); sucrose fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, and alkyl alkanolamides. These surfactants may be used alone or in combination of two or more.

[0136] The number of carbon atoms in the alkyl group in the polyoxyethylene alkyl ether that can be used here is not particularly limited. For example, the number of carbon atoms in the alkyl group is preferably 5 or more, more preferably 6 or more, even more preferably 7 or more, particularly preferably 8 or more, and specifically 9 or more. For example, the number of carbon atoms in the alkyl group is preferably 12 or less, more preferably 11 or less. The number of carbon atoms in the alkyl group is, for example, 10. Furthermore, the number of moles of ethylene oxide added in the polyoxyethylene alkyl ether is not particularly limited, but is preferably 4 or more, more preferably 5 or more, and preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, and particularly preferably 7 or less. From the viewpoint of reducing surface defects, polyoxyethylene octyl ether having a mole number of ethylene oxide added of 4 to 10 (for example, 6) can be preferably used as the surfactant used in the polishing composition and / or semiconductor wetting agent disclosed herein.

[0137] Specific examples of nonionic surfactants containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether ... 2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene Examples of the hydroxypropyl methylcellulose include polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

[0138] The Mw of the surfactant is preferably less than 2000, more preferably 1500 or less, even more preferably 700 or less, and particularly preferably 500 or less. When the surfactant is a polyoxyalkylene derivative, its Mw is preferably 100 or more, more preferably 200 or more, and even more preferably 300 or more. A polishing composition and / or a semiconductor wetting agent containing a surfactant having an Mw in this range can suitably reduce surface defects. The molecular weight of the surfactant can be calculated from the chemical formula.

[0139] The concentration of the surfactant in the polishing composition and / or semiconductor wetting agent is not particularly limited, and can be, for example, 0.0001% by weight or more, preferably 0.0003% by weight or more. The concentration of the surfactant in the polishing composition and / or surfactant is usually preferably 0.2% by weight or less, more preferably 0.1% by weight or less, and may be 0.05% by weight or less. In a preferred embodiment, the concentration of the surfactant in the polishing composition and / or surfactant may be 0.0001% by weight or more and 0.002% by weight or less, or may be 0.0002% by weight or more and 0.001% by weight or less. In another preferred embodiment, the concentration of the surfactant in the polishing composition and / or surfactant may be 0.005% by weight or more and 0.03% by weight or less.

[0140] The molar ratio of the polyvinyl alcohol content to the surfactant content in the polishing composition and / or semiconductor wetting agent is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less (e.g., 0.07 or less). In addition, the molar ratio of the polyvinyl alcohol content to the surfactant content in this embodiment is usually 0.01 or more, preferably 0.02 or more, more preferably 0.03 or more, and even more preferably 0.04 or more. When polyvinyl alcohol and surfactant are contained at such a compounding ratio, aggregation of polyvinyl alcohol is appropriately suppressed, and surface defects are easily reduced.

[0141] (Water-soluble polymers other than polyvinyl alcohol) Examples of water-soluble polymers other than polyvinyl alcohol include compounds containing a hydroxyl group, a carboxyl group, an acyloxy group, a sulfo group, an amide structure, an imide structure, a quaternary ammonium structure, a heterocyclic structure, a vinyl structure, or the like in the molecule. Furthermore, as water-soluble polymers other than polyvinyl alcohol, any of natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds may be used. Examples of natural polymer compounds include, but are not limited to, polysaccharides, etc. Examples of semi-synthetic polymer compounds include, but are not limited to, cellulose derivatives, starch derivatives, etc. Examples of synthetic polymer compounds include, but are not limited to, polymers having oxyalkylene units, polymers containing nitrogen atoms, etc. Examples of nitrogen-containing polymers include N-vinyl polymers and N-(meth)acryloyl polymers. Specific examples of these compounds will be described later.

[0142] The polysaccharides are not particularly limited, but examples thereof include carrageenan, xanthan gum, glycogen, alginic acid, pectin, pectic acid, starch, starch derivatives, amylose, amylopectin, agar, curdlan, pullulan, guar gum, konjac mannan, and tamarind gum.

[0143] The cellulose derivative is not particularly limited, and examples thereof include cellulose derivatives such as hydroxyethyl cellulose (hereinafter also referred to simply as "HEC"), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, and carboxymethyl cellulose, as well as pullulan. One type of cellulose derivative may be used alone, or two or more types may be used in combination. Here, the cellulose derivative refers to a cellulose that contains β-glucose units as the main repeating unit and in which some of the hydroxyl groups of cellulose are substituted with other substituents.

[0144] The starch derivative is not particularly limited, but examples thereof include cationic starch, starch phosphate, carboxymethyl starch salt, etc. Here, the starch derivative is a polymer containing an α-glucose unit as the main repeating unit.

[0145] Examples of polymers having oxyalkylene units include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO. Among these, block copolymers of EO and PO or random copolymers of EO and PO are preferred. Block copolymers of EO and PO may be diblock copolymers or triblock copolymers containing a PEO block and a polypropylene oxide (PPO) block. Examples of the triblock copolymers include PEO-PPO-PEO triblock copolymers and PPO-PEO-PPO triblock copolymers. Among these, PEO-PPO-PEO triblock copolymers are more preferred.

[0146] In a block or random copolymer of EO and PO, the molar ratio of EO to PO constituting the copolymer [EO / PO] is preferably greater than 1, more preferably at least 2, and even more preferably at least 3, from the viewpoints of water solubility, washability, etc. In a more preferred embodiment, the molar ratio [EO / PO] is, for example, at least 5.

[0147] Examples of N-vinyl polymers include polymers containing repeating units derived from monomers having a nitrogen-containing heterocycle (e.g., lactam ring). Examples of such polymers include homopolymers and copolymers of N-vinyl lactam monomers (e.g., copolymers containing more than 50% by weight of N-vinyl lactam monomers), homopolymers and copolymers of N-vinyl linear amides (e.g., copolymers containing more than 50% by weight of N-vinyl linear amides), etc.

[0148] Specific examples of N-vinyl lactam monomers (i.e., compounds having a lactam structure and an N-vinyl group in one molecule) include N-vinylpyrrolidone (VP), N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam (VC), N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, etc. Specific examples of polymers containing N-vinyl lactam monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), block copolymers, alternating copolymers, and graft copolymers containing polymer chains containing one or both of VP and VC.

[0149] Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide.

[0150] Examples of N-(meth)acryloyl type polymers include homopolymers and copolymers of N-(meth)acryloyl type monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl type monomers exceeds 50% by weight). Examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group.

[0151] Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of polymers containing chain amides having an N-(meth)acryloyl group as a monomer unit include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by weight).

[0152] Examples of cyclic amides having an N-(meth)acryloyl group include N-acryloylmorpholine, N-acryloylthiomorpholine, N-acryloylpiperidine, N-acryloylpyrrolidine, N-methacryloylmorpholine, N-methacryloylpiperidine, and N-methacryloylpyrrolidine. Examples of polymers containing cyclic amides having an N-(meth)acryloyl group as monomer units include acryloylmorpholine-based polymers (PACMO). Typical examples of acryloylmorpholine-based polymers include homopolymers of N-acryloylmorpholine (ACMO) and copolymers of ACMO (e.g., copolymers with a copolymerization ratio of ACMO exceeding 50% by weight). In acryloylmorpholine-based polymers, the proportion of moles of ACMO units in the total moles of repeating units is typically 50% or more, and suitably 80% or more (e.g., 90% or more, typically 95% or more). All repeating units of the water-soluble polymer may be substantially composed of ACMO units.

[0153] Other examples of polymers having nitrogen atoms include imine derivatives such as polyhydroxylethylacrylamide (PHEAA), poly-N-vinylimidazole (PVI), poly-N-vinylcarbazole, poly-N-vinylpiperidine, etc. The polymers having nitrogen atoms may be homopolymers or copolymers, and one type may be used alone or two or more types may be used in combination.

[0154] The water-soluble polymer other than polyvinyl alcohol may be a water-soluble polymer having at least one functional group selected from a cationic group, an anionic group, and a nonionic group in the molecule. From the viewpoints of reducing aggregates and improving cleaning properties, a nonionic polymer is preferably used as the water-soluble polymer.

[0155] Specific examples of other water-soluble polymers include water-soluble polymers such as polycarboxylic acids, polycarboxylic acid amides, polycarboxylic acid esters, polyphosphonic acids, polysulfonic acids such as polystyrene sulfonic acid, ethylene oxide polymers, vinyl polymers, and cationic polymers, as well as copolymers, salts, and derivatives thereof. Specific examples of polycarboxylic acids, polycarboxylic acid amides, polycarboxylic acid esters, and polycarboxylic acid salts include polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, ammonium polymethacrylate salts, sodium polymethacrylate salts, polymaleic acid, polyitaconic acid, polyfumaric acid, poly(p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, methyl polyacrylate, ethyl polyacrylate, ammonium polyacrylate salts, sodium polyacrylate salts, polyamic acid, ammonium polyamic acid salts, sodium polyamic acid salts, and polyglyoxylic acid. Specific examples of cationic polymers include cationized cellulose derivatives, cationic starch, cationized guar gum derivatives, diallyl quaternary ammonium salt / acrylamide copolymers, quaternized polyvinylpyrrolidone derivatives, and dicyandiamide-diethylenetriamine condensates. These water-soluble polymers may be used alone or in combination of two or more.

[0156] The weight average molecular weight (Mw) of water-soluble polymers is typically 2 × 10 3 That's 5 x 10 3 May be greater than 1 x 10 4 May be more than 5 x 10 4 It may be more than 10 x 10 4 It may be 20 x 10 or more. 4 The Mw of the dispersant may be 100×10 4 It may be less than 50 x 10 4 It may be less than 45 x 10 4 It may be 40 x 10 or less. 4 It may be the following:

[0157] The concentration of the water-soluble polymer in the polishing composition and / or semiconductor wetting agent is not particularly limited, and can be, for example, 0.0001% by weight or more, preferably 0.0003% by weight or more. Furthermore, the concentration of the water-soluble polymer in the polishing composition and / or semiconductor wetting agent is usually preferably 0.2% by weight or less, more preferably 0.1% by weight or less, and may be 0.05% by weight or less. In a preferred embodiment, the concentration of the water-soluble polymer in the polishing composition and / or semiconductor wetting agent may be 0.0001% by weight or more and 0.002% by weight or less, or 0.0002% by weight or more and 0.001% by weight or less. In another preferred embodiment, the concentration of the water-soluble polymer in the polishing composition and / or semiconductor wetting agent may be 0.005% by weight or more and 0.03% by weight or less.

[0158] The molar ratio of the polyvinyl alcohol content to the water-soluble polymer content in the polishing composition and / or semiconductor wetting agent is preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less (e.g., 4 or less). In addition, the molar ratio of the polyvinyl alcohol content to the water-soluble polymer content in such an embodiment is usually 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more, and even more preferably 1 or more. When polyvinyl alcohol and the water-soluble polymer are contained at such a compounding ratio, aggregation of the polyvinyl alcohol is appropriately suppressed, and surface defects are likely to be reduced.

[0159] (pH adjuster) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain a pH adjuster. The pH adjuster is added mainly for the purpose of adjusting the pH of the polishing composition and / or semiconductor wetting agent disclosed herein. The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and known compounds can be used. Examples include alkalis and acids.

[0160] In this specification, alkali refers to a compound that dissolves in water and has the function of increasing the pH of the aqueous solution. Examples of alkali that can be used include nitrogen-containing organic or inorganic alkalis, alkali metal hydroxides, alkaline earth metal hydroxides, various carbonates and hydrogen carbonates, etc. Examples of nitrogen-containing alkalis include quaternary ammonium compounds, quaternary phosphonium compounds, ammonia, and amines (preferably water-soluble amines).

[0161] Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of carbonates or bicarbonates include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, and sodium carbonate. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole. Specific examples of quaternary phosphonium compounds include quaternary phosphonium hydroxides such as tetramethylphosphonium hydroxide and tetraethylphosphonium hydroxide.

[0162] As the quaternary ammonium compound, quaternary ammonium salts (typically strong bases) such as tetraalkylammonium salts and hydroxyalkyltrialkylammonium salts can be preferably used. The anion component in such quaternary ammonium salts is, for example, OH - , F - , Cl - , Br - , I - , ClO 4- , B.H. 4- Among these, a preferred example is where the anion is OH - Specific examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide; hydroxyalkyltrialkylammonium hydroxides such as 2-hydroxyethyltrimethylammonium hydroxide (also known as choline); and the like.

[0163] Among these alkalis, at least one alkali selected from alkali metal hydroxides, quaternary ammonium hydroxides, and ammonia can be preferably used. Among these, tetraalkylammonium hydroxides (e.g., tetramethylammonium hydroxide) and ammonia are more preferred, and ammonia is particularly preferred.

[0164] According to one embodiment of the present invention, the method further includes an alkali addition step of adding an alkali to the polyvinyl alcohol composition obtained through the submerged addition step. By subjecting the polyvinyl alcohol composition of the present invention to the alkali addition step to obtain an alkaline polyvinyl alcohol composition, the composition can be preferably used as a polishing composition and / or a wetting agent for semiconductors. The alkali addition step is preferably carried out by mixing the polyvinyl alcohol composition obtained through the submerged addition step with a third liquid containing an alkali.

[0165] As used herein, the term "acid" refers to a compound that dissolves in water and lowers the pH of the aqueous solution. Either an inorganic or organic acid may be used. Inorganic acids include, but are not limited to, sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Organic acids include, but are not limited to, carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid, as well as methanesulfonic acid, ethanesulfonic acid, and isethionic acid. Among these, maleic acid or nitric acid is more preferred, and maleic acid is even more preferred.

[0166] The content of the pH adjuster is not particularly limited and may be selected appropriately so that the pH of the polyvinyl alcohol composition according to one embodiment of the present invention, the semiconductor wetting agent according to one embodiment of the present invention, and the polishing composition according to one embodiment of the present invention is within the desired range.

[0167] When the polishing composition and / or semiconductor wetting agent disclosed herein contains alkali, the alkali concentration in the polishing liquid is not particularly limited. From the viewpoint of the action on the substrate surface, the concentration is usually preferably 0.001 wt% or more of the polishing liquid, more preferably 0.003 wt% or more (for example, 0.005 wt% or more). Also, from the viewpoint of reducing haze, the concentration is suitably less than 0.3 wt%, preferably less than 0.1 wt%, more preferably less than 0.05 wt%, and particularly preferably less than 0.03 wt% (for example, less than 0.025 wt%, or even less than 0.01 wt%).

[0168] (chelating agent) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain a chelating agent. The chelating agent may be used singly or in combination of two or more. Examples of the chelating agent include aminocarboxylic acid chelating agents and organic phosphonic acid chelating agents. Suitable examples of the chelating agent include ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Examples of the preservatives and antifungal agents include isothiazolinone compounds, parahydroxybenzoic acid esters, phenoxyethanol, etc.

[0169] (Organic acids, organic acid salts, inorganic acids, inorganic acid salts) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain organic acids and their salts, and inorganic acids and their salts. The organic acids and their salts, and inorganic acids and their salts, can be used singly or in combination. Examples of organic acids include fatty acids such as formic acid, acetic acid, and propionic acid; aromatic carboxylic acids such as benzoic acid and phthalic acid; itaconic acid, citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, fumaric acid, succinic acid, glycolic acid, malonic acid, gluconic acid, alanine, glycine, lactic acid; organic sulfonic acids such as hydroxyethylidene diphosphate (HEDP) and methanesulfonic acid; and organic phosphonic acids such as nitrilotris(methylene phosphoric acid) (NTMP) and phosphonobutanetricarboxylic acid (PBTC). Examples of organic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of organic acids. Examples of inorganic acids include hydrochloric acid, phosphoric acid, sulfuric acid, phosphonic acid, nitric acid, phosphinic acid, boric acid, carbonic acid, etc. Examples of inorganic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of inorganic acids.

[0170] (Metal corrosion inhibitor) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain a metal corrosion inhibitor.Specific examples of metal corrosion inhibitors include nitrogen-containing heterocyclic compounds such as pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyrindine compounds, indolizine compounds, indole compounds, isoindole compounds, indazole compounds, purine compounds, quinolizine compounds, quinoline compounds, isoquinoline compounds, naphthyridine compounds, phthalazine compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, buteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, and furazan compounds.These metal corrosion inhibitors may be used alone or in combination of two or more.

[0171] (oxidizing agent) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain an oxidizing agent. Specific examples of oxidizing agents include peroxides, periodic acid, periodates, permanganates, vanadates, hypochlorites, iron oxides, and ozone. Specific examples of peroxides include hydrogen peroxide, peracetic acid, percarbonates, urea peroxide, perchloric acid, perchlorates, and persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate. These oxidizing agents may be used alone or in combination of two or more.

[0172] When the polishing composition and / or semiconductor wetting agent disclosed herein is used on a substrate having a surface made of silicon single crystal, it is preferable that it is substantially free of the above-mentioned oxidizing agent. This is because the presence of an oxidizing agent can oxidize the surface of the silicon substrate, forming an oxide film, which can reduce the effectiveness of the composition on the substrate surface. Here, "substantially free of oxidizing agent" means that an oxidizing agent is not intentionally added, and it is acceptable that a trace amount of oxidizing agent is inevitably included due to raw materials, manufacturing method, etc. The above-mentioned "trace amount" means that the molar concentration of the oxidizing agent is 0.0005 mol / L or less (preferably 0.0001 mol / L or less, more preferably 0.00001 mol / L or less, and particularly preferably 0.000001 mol / L or less). A preferred embodiment of the polishing composition and / or semiconductor wetting agent does not contain the above-mentioned oxidizing agent.

[0173] (preservatives, anti-mold agents) The polishing composition and / or semiconductor wetting agent disclosed herein may further contain an antiseptic and / or antifungal agent. Specific examples of the antiseptic and antifungal agent include isothiazolin-based preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, parahydroxybenzoic acid esters, phenoxyethanol, etc. These antiseptics and antifungal agents may be used alone or in combination of two or more.

[0174] (pH) The pH of the polishing composition and / or semiconductor wetting agent disclosed herein is not particularly limited.The pH is preferably 1.0 or more, more preferably 2.0 or more, typically 8.0 or more, preferably 8.5 or more, more preferably 9.0 or more, even more preferably 9.3 or more, for example 9.5 or more.On the other hand, the pH of the polishing composition and / or semiconductor wetting agent is suitably 12.0 or less, preferably 11.0 or less, more preferably 10.8 or less, and even more preferably 10.5 or less.

[0175] The pH can be determined by using a pH meter (for example, a glass electrode hydrogen ion concentration indicator (model number F-23) manufactured by Horiba, Ltd.) and performing three-point calibration using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C), neutral phosphate pH buffer solution, pH: 6.86 (25°C), carbonate pH buffer solution, pH: 10.01 (25°C)), then placing the glass electrode in the composition to be measured and measuring the value after stabilization for at least two minutes.

[0176] [Polishing solution and rinse solution] The polishing composition disclosed herein is typically supplied to a substrate in the form of a polishing liquid containing the polishing composition and used to polish the substrate. The semiconductor wetting agent disclosed herein is typically supplied to a substrate in the form of a rinse liquid containing the semiconductor wetting agent and used to rinse the substrate. The polishing liquid may be prepared, for example, by diluting (typically with water) any of the polishing compositions disclosed herein. Alternatively, the polishing composition may be used as a polishing liquid as is. In other words, the concept of a polishing composition in the technology disclosed herein encompasses both a polishing liquid (working slurry) that is supplied to a substrate and used to polish the substrate, and a concentrated liquid (i.e., undiluted polishing liquid) that is diluted and used as a polishing liquid. The rinse liquid may be prepared, for example, by diluting (typically with water) any of the semiconductor wetting agents disclosed herein. Alternatively, the semiconductor wetting agent may be used as a rinse liquid as is. That is, the concept of a semiconductor wetting agent in the technology disclosed herein includes both a rinse liquid that is supplied to a substrate and used to rinse the substrate, and a concentrated liquid (i.e., a stock solution of a rinse liquid) that is diluted and used as a rinse liquid.Another example of a polishing liquid containing the polishing composition disclosed herein is a polishing liquid obtained by adjusting the pH of the composition.Furthermore, another example of a rinse liquid containing the semiconductor wetting agent disclosed herein is a rinse liquid obtained by adjusting the pH of the composition.

[0177] (Concentrate) The polishing composition and / or semiconductor wetting agent disclosed herein may be in a concentrated form before being supplied to a substrate. That is, the polishing composition and / or semiconductor wetting agent is in the form of a concentrated polishing liquid and / or rinse liquid, and can also be understood as a stock solution of the polishing liquid and / or rinse liquid. Such concentrated polishing compositions and / or semiconductor wetting agents are advantageous from the viewpoints of convenience and cost reduction during production, distribution, storage, etc. The concentration ratio of the concentrate is not particularly limited, and can be, for example, about 2 to 100 times in volume terms, and is usually about 5 to 50 times (e.g., about 10 to 40 times).

[0178] Such a concentrate can be diluted at a desired time to prepare a polishing liquid (working slurry), which can then be supplied to a substrate. The dilution can be performed, for example, by adding water to the concentrate and mixing the mixture.

[0179] The content of abrasive grains in the concentrate can be, for example, 50% by mass or less. From the viewpoint of the handleability of the concentrate (e.g., dispersion stability of the abrasive grains and filterability), the content of abrasive grains in the concentrate is usually preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less (e.g., 10% by mass or less). Furthermore, from the viewpoint of convenience and cost reduction during production, distribution, storage, etc., the content of abrasive grains can be, for example, 0.5% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, for example, 3% by mass or more. In a preferred embodiment, the content of abrasive grains may be 4% by mass or more, or may be 5% by mass or more.

[0180] [Preparation of polishing composition and semiconductor wetting agent] The polishing composition used in the technology disclosed herein may be a single-component type or a multi-component type, such as a two-component type. For example, the polishing composition may be configured so that a polishing liquid is prepared by mixing Part A, which contains at least abrasive grains among the components of the polishing composition, with Part B, which contains at least a portion of the remaining components, and then mixing and diluting these components at an appropriate time as needed. The semiconductor wetting agent used in the technology disclosed herein may be a single-component type or a multi-component type, such as a two-component type. For example, the polishing composition may be configured so that a rinse liquid is prepared by mixing Part A, which contains at least polyvinyl alcohol among the components of the semiconductor wetting agent, with Part B, which contains at least a portion of the remaining components, and then mixing and diluting these components at an appropriate time as needed.

[0181] The method for preparing the polishing composition and / or the wetting agent for semiconductors is not particularly limited. For example, the components constituting the polishing composition and / or the wetting agent for semiconductors may be mixed using a well-known mixing device such as a blade-type agitator, an ultrasonic disperser, or a homomixer. The manner in which these components are mixed is not particularly limited. For example, all the components may be mixed at once, or may be mixed in an appropriately set order.

[0182] [substrate] The polishing composition and / or semiconductor wetting agent according to one embodiment of the present invention can be used to polish and / or rinse substrates of various materials and shapes. Examples of substrate materials include metals or semimetals, such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, hafnium, cobalt, and stainless steel, or alloys thereof; glassy materials, such as quartz glass, aluminosilicate glass, and glassy carbon; ceramic materials, such as alumina, silica, sapphire, silicon nitride, tantalum nitride, and titanium carbide; compound semiconductor substrate materials, such as silicon carbide, gallium nitride, and gallium arsenide; and resin materials, such as polyimide resin. The substrate may be composed of multiple of these materials. It may also be a metal, a substrate containing oxygen and silicon atoms, a substrate containing silicon-silicon bonds, or a substrate containing nitrogen and silicon atoms. Substrates containing oxygen and silicon atoms include, for example, silicon oxide (SiO) and tetraethyl orthosilicate (TEOS) polycondensates. Examples of substrates having silicon-silicon bonds include polysilicon, amorphous silicon, single crystal silicon, n-type doped single crystal silicon, p-type doped single crystal silicon, Si-based alloys such as SiGe, etc. Examples of substrates having nitrogen atoms and silicon atoms include silicon nitride films, substrates having silicon-nitrogen bonds such as SiCN (silicon carbonitride), etc.

[0183] The polishing composition and / or semiconductor wetting agent according to one embodiment of the present invention can be particularly preferably used for polishing and / or rinsing silicon surfaces, typically silicon wafers. A typical example of the silicon wafer referred to here is a silicon single crystal wafer, for example, a silicon single crystal wafer obtained by slicing a silicon single crystal ingot.

[0184] The polishing composition and / or semiconductor wetting agent disclosed herein can be preferably applied to a polishing process of a substrate (e.g., a silicon wafer) and a subsequent rinsing process. Before the polishing process with the polishing composition and / or semiconductor wetting agent disclosed herein, the substrate may be subjected to a general treatment that can be applied to a substrate in a process upstream of the polishing process, such as lapping or etching.

[0185] The polishing composition and / or semiconductor wetting agent disclosed herein can be preferably used, for example, in polishing a substrate (e.g., a silicon wafer) that has been prepared in an upstream process to have a surface roughness of 0.1 nm to 100 nm, followed by rinsing. The surface roughness Ra of the substrate can be measured, for example, using a laser scanning surface roughness meter "TMS-3000WRC" manufactured by Schmitt Measurement Systems Inc. Use in the final polishing (finish polishing) or the polishing immediately before it and the rinsing thereafter is effective, and use in the final polishing and the rinsing thereafter is particularly preferred. Here, final polishing refers to the final polishing step in the manufacturing process of the target object (i.e., a step in which no further polishing is performed after that step).

[0186] <Polishing and rinsing> The polishing composition disclosed herein can be used for polishing a substrate, for example, in an embodiment including the following procedure. The semiconductor wetting agent disclosed herein can be used for rinsing a substrate, for example, in an embodiment including the following procedure. A preferred embodiment of a method for polishing a substrate (e.g., a silicon wafer) using the polishing composition disclosed herein and a method for rinsing a substrate (e.g., a silicon wafer) using the semiconductor wetting agent disclosed herein will be described below.

[0187] That is, a polishing liquid containing any of the polishing compositions disclosed herein is prepared. The preparation of the polishing liquid may include adjusting the concentration (e.g., diluting) of the polishing composition, adjusting the pH, or the like to prepare the polishing liquid. Alternatively, the polishing composition may be used as is as the polishing liquid.

[0188] Next, the polishing liquid is supplied to the substrate, and polishing is performed by a conventional method. For example, when performing finish polishing of a silicon wafer, typically, a silicon wafer that has undergone a lapping process is set in a general polishing device, and a polishing liquid is supplied to the surface to be polished of the silicon wafer through the polishing pad of the polishing device. Typically, while continuously supplying the polishing liquid, the polishing pad is pressed against the surface to be polished of the silicon wafer, and the two are moved relative to each other (for example, rotated). Polishing of the substrate is completed through this polishing process.

[0189] Next, a rinse solution containing any of the semiconductor wetting agents disclosed herein is prepared. Preparing the rinse solution may involve adjusting the concentration (e.g., diluting) of the semiconductor wetting agent, adjusting the pH, or the like to prepare the rinse solution. Alternatively, the semiconductor wetting agent may be used as is as the rinse solution.

[0190] Next, the rinse liquid is supplied to the substrate, and in the same manner as in the polishing described above, a polishing pad is pressed against the polished surface of the silicon wafer, and the two are moved relative to each other (for example, rotated). Through these steps, the rinsing of the substrate is completed.

[0191] (Polishing pad) The polishing pad used in the polishing step and / or rinsing step is not particularly limited. For example, a polishing pad of a foamed polyurethane type, a nonwoven fabric type, a suede type, or the like can be used. Each polishing pad may contain abrasive grains or may not contain abrasive grains. Usually, a polishing pad that does not contain abrasive grains is preferably used.

[0192] [Cleaning] A substrate polished and / or rinsed with the polishing composition and / or semiconductor wetting agent according to one embodiment of the present invention is typically cleaned. Cleaning can be performed using an appropriate cleaning solution. The cleaning solution used is not particularly limited, and examples of cleaning solutions that are commonly used in the semiconductor field include SC-1 cleaning solution and SC-2 cleaning solution. Examples of SC-1 cleaning solutions include a mixture of ammonium hydroxide (NH4OH), hydrogen peroxide (HO2), and water (HO). Examples of SC-2 cleaning solutions include a mixture of HCl, HO2, and HO. The temperature of the cleaning solution can be, for example, from room temperature to approximately 90°C. Room temperature is typically approximately 15°C to 25°C. From the perspective of improving the cleaning effect, a cleaning solution at approximately 40°C to 85°C can be preferably used. [Example]

[0193] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, the term "parts" is used, but unless otherwise specified, it means "parts by mass." In the following description, PVA is a saponified polyvinyl acetate.

[0194] (Preparation of Solution (1)) To a 3 L container, 1200 parts of water at room temperature (25°C) was added, followed by 600 parts of polyvinyl alcohol (PVA-124, manufactured by Kuraray Co., Ltd., degree of polymerization 2400, degree of saponification 98.0-99.0 mol%) (solids concentration 3.3 mass%). The mixture was stirred at 250 rpm using a mechanical stirrer with a propeller blade (manufactured by Shinto Scientific Co., Ltd., product name Three-One Motor, model number BLh1200), and the temperature of the solution in the container was raised to above 90°C, dispersing and swelling the polyvinyl alcohol. The temperature was then raised to 95°C while continuing to stir, and the mixture was stirred for 1 hour while maintaining that temperature, dissolving the polyvinyl alcohol and obtaining an aqueous polyvinyl alcohol solution.

[0195] The container containing the aqueous polyvinyl alcohol solution was then immersed in a water bath to cool it. While continuing to stir the aqueous polyvinyl alcohol solution, it was cooled in the water bath, and cooling was stopped when the temperature of the aqueous polyvinyl alcohol solution reached 25°C. It took about 30 minutes to cool from 95°C to 25°C. Therefore, the cooling rate at this time was calculated to be about 2°C / min. The resulting aqueous polyvinyl alcohol solution was designated solution (1).

[0196] [Addition experiment] To carry out the addition experiment of the solution (1), an apparatus 10 shown in Fig. 1 was prepared. Fig. 1 is a diagram showing a schematic diagram of the apparatus 10 used in the experiment of addition in liquid.

[0197] As shown in FIG. 1, solutions (1) 21a and 21b are placed in beakers 11 and 12, respectively (e.g., 900 parts each). One end of tube 15a is connected to the suction side of pump 13, and one end of tube 15b is connected to the discharge side. The other end of tube 15a is immersed in solution (1) 21b in beaker 12, and the other end of tube 15b is immersed in solution (1) 21a in beaker 11. This allows solution (1) 21b in beaker 12 to be directly added (submerged addition) to solution (1) 21a in beaker 11 by operating pump 13 via tubes 15a and 15b. In this experiment, both the first and second liquids are solutions (1).

[0198] Example 1 An experiment was conducted to add the solution (1) obtained above to a liquid using the apparatus 10 shown in Figure 1. 900 parts of solution (1) 21a and 21b were placed in beakers 11 and 12, respectively. The diameters of the tubes 15a and 15b used were 5 mm, and the inner diameter of the beaker 11 (stirring vessel) was 20 cm. The addition rate of solution (1) 21b to solution (1) 21a was 150-160 mL / min, and the submerged addition of solution (1) 21b was carried out for 5 minutes. Stirring was not performed during the submerged addition. After the submerged addition, the beaker 11 was stirred (at 100 rpm) using a three-one motor (not shown), and the temperature of the solution (1) to be added was 25°C. The ratio (L / D) of the stirring blade diameter (L) to the inner diameter (D) of the stirring vessel was 0.5. After stirring was completed, the solution (1) 21a in the beaker 11 was collected and used as the polyvinyl alcohol composition (hereinafter referred to as PVA composition) (1) of Example 1.

[0199] (Comparative Example 1) In Comparative Example 1, the addition was performed by dropwise addition. In the apparatus 10 shown in FIG. 1, the other end of the tube 15b was removed from the solution (1) 21a in the beaker 11 and positioned 50 to 60 cm above the solution (1) 21a (for example, the tube 15b was held with a clamp or the like), and the dropwise addition experiment was performed. The rate of addition of the solution (1) 21b to the solution (1) 21a was 150 to 160 mL / min, and the solution (1) 21b was added dropwise for 5 minutes. No stirring was performed during the submerged addition. After the submerged addition, the beaker 11 was stirred (at 100 rpm) using a three-one motor (apparatus), and the temperature of the solution (1) to be added was 25°C. After the stirring was completed, the solution (1) 21a in the beaker 11 and the solution (1) 21b in the beaker 12 were combined and collected, and this was designated as the PVA composition (2) of Comparative Example 1.

[0200] (Reference example 1) The solution (1) (prepared and left to stand for 10 minutes) that was not subjected to the addition experiment was used as PVA composition (3).

[0201] [Evaluation of filterability] The filterability of the solution used in the addition experiment was evaluated. DIW correction was performed to eliminate individual differences between filters when evaluating filterability. DIW correction involves correcting for differences in filtration capacity between filters using a coefficient, which is calculated based on filtration performance (filtration time and amount of liquid passing) using deionized water.

[0202] ·control First, 600 g of deionized water at 25°C was filtered through each filter. The filter material was polypropylene, with a pore size of 0.2 μm. The filtration was performed by suction filtration. The suction pressure during filtration was 0.0125 MPa. The filtrate weight (g) after a liquid-passing time of 100 seconds and after a liquid-passing time of 600 seconds were measured. These filtrate weights (g) when using deionized water were used for DIW correction of each filter.

[0203] ·PVA composition 600 g (25°C) of each PVA composition obtained above was subjected to suction filtration (suction pressure 0.0125 MPa) using the filter used in the control. The amount of liquid passing through was measured at 60-second intervals. Table 1 shows the amount of liquid passing through for each PVA composition. The values were corrected for DIW.

[0204] Filtration weight DIW correction (Calculation of DIW correction value for each evaluation sample) The filtration weight after 100 seconds of deionized water filtration and the filtration weight after 600 seconds of water filtration were divided by six to obtain the average value, which was designated as the "filtration weight (average value) after 100 seconds of water filtration." The filtration weight (average value) after 100 seconds of water filtration was calculated for each filter used to evaluate the filterability of each evaluation sample (submerged addition, dropwise addition, and static solution). This is the "filtration weight (average value) after 100 seconds of water filtration for each evaluation sample" in the following formula (1).

[0205] The average filtration weight after 100 seconds of liquid passage was calculated for all evaluation samples that underwent filterability evaluation. That is, the "average filtration weight after 100 seconds of liquid passage for all evaluation samples" refers to the average filtration weight (average value for all evaluation samples) after 100 seconds of deionized water passage through the filters that underwent filterability evaluation for solutions that were added submerged, added dropwise, and left standing.

[0206] Using the filtration weight (average value) of each evaluation sample obtained above after 100 seconds of liquid passage and the "average filtration weight value of all evaluation samples after 100 seconds of liquid passage," the "DIW correction value of each evaluation sample" was calculated for each evaluation sample using the following formula (2).

[0207] (Calculation of filtration weight DIW correction) The filtered weight of each evaluation sample was corrected for the liquid-passing time based on deionized water using the "DIW correction value of each evaluation sample" as follows: Table 1 shows the filtered weight (filtered weight DIW correction) obtained by applying the "DIW correction value of each evaluation sample" to each liquid-passing time (specified value) of each evaluation sample.

[0208]

number

[0209] [Table 1]

[0210] As shown in Table 1, the PVA composition (1) that was added submerged had significantly better filterability than the PVA composition (2) that was added dropwise, demonstrating that the filterability is improved by submerged addition. It was also found that the PVA composition (1) that was added submerged had almost the same filterability as the PVA composition (3) that was left to stand without undergoing the submerged addition step. This indicates that the generation of aggregates due to addition was significantly suppressed when the PVA composition was added submerged.

[0211] This shows that a polishing composition and / or a wetting agent for semiconductors containing the PVA composition (1) can be used to polish and / or rinse substrates such as silicon wafers, thereby reducing surface defects (e.g., LPD: Light Point Defects, etc.) and significantly improving the surface quality of the substrate. [Explanation of symbols]

[0212] 10 Experimental equipment for liquid addition, 11, 12 beakers, 13 pumps, 15a, 15b tube, 21a, 21b solution (1).

Claims

1. A method for producing a wetting agent for a semiconductor containing a polyvinyl alcohol composition, comprising: The wetting agent for semiconductors does not contain abrasive grains, the polyvinyl alcohol composition is obtained by a submerged addition step of submerging either a first liquid containing polyvinyl alcohol and water or a second liquid other than the first liquid, and A method for producing a wetting agent for semiconductors, wherein the submerged addition step is a step of submergedly adding the first liquid to the second liquid held in a container having a stirring means.

2. 2. The method for producing a wetting agent for semiconductors according to claim 1, wherein the first liquid is obtained by heating a polyvinyl alcohol dispersion obtained by dispersing polyvinyl alcohol in water to 85 to 98°C and then cooling it to 15 to 50°C.

3. A method for producing a wetting agent for a semiconductor containing a polyvinyl alcohol composition, comprising: the polyvinyl alcohol composition is obtained by a submerged addition step of submerging either a first liquid containing polyvinyl alcohol and water or a second liquid other than the first liquid, and The method for producing a wetting agent for semiconductors, wherein the first liquid is obtained by heating a polyvinyl alcohol dispersion obtained by dispersing polyvinyl alcohol in water to 85 to 98°C and then cooling it to 15 to 50°C.

4. The method for producing a wetting agent for semiconductors according to any one of claims 1 to 3, further comprising a filtration step of filtering the polyvinyl alcohol composition obtained through the liquid addition step.

5. 5. The method for producing a wetting agent for semiconductors according to claim 1, wherein in the liquid addition step, the content of the polyvinyl alcohol in the polyvinyl alcohol composition is 10 mass% or less with respect to the total mass of the polyvinyl alcohol composition.

6. The method for producing a wetting agent for semiconductors according to any one of claims 1 to 5, further comprising an alkali addition step of adding an alkali to the polyvinyl alcohol composition obtained through the liquid addition step.

7. A polishing composition comprising a wetting agent for semiconductors produced by the production method according to any one of claims 1 to 6 and abrasive grains.

8. A method for producing a polishing composition, comprising mixing the wetting agent for semiconductors produced by the method according to any one of claims 1 to 6 with abrasive grains.

Images