Method for producing polishing composition, and polishing composition

Abstract

Provided are: a polishing composition which is effective in reducing surface defects after polishing in terms of a composition comprising a cellulose derivative; a substrate protective agent; and methods for producing the polishing composition and the substrate protective agent. Provided is a method for producing a polishing composition containing abrasive grains, a basic compound, a cellulose derivative, and a surfactant. The production method comprises a step (A) in which a raw material cellulose derivative is dissolved in a solvent to produce a raw material cellulose derivative solution, and further comprises a step (B1) in which the raw material cellulose derivative solution is heated, and a step (B2) in which the raw material cellulose derivative solution is heated. A step (B1) for adding a starting material surfactant to the starting material cellulose derivative solution after the step (B1); alternatively, a step (C1) in which a starting material surfactant is added to the starting material cellulose derivative solution to produce an additive mixture, and a step (C2) in which the additive mixture is heated.

Description

Technical Field

[0001] The present invention relates to a method for producing a polishing composition and a polishing composition. In addition, the present invention also relates to a method for producing a substrate protective agent and a substrate protective agent. This application claims priority based on Japanese patent application No. 2022-158494 filed on September 30, 2022, and the entire contents of the application are incorporated herein by reference. Background Art

[0002] For the surface of materials such as metal, semi-metal, non-metal, and its oxide, use grinding composition to carry out precision grinding.For example, the surface of silicon wafer used as the constituent element of semiconductor device etc. is usually finished into high-quality mirror surface through grinding process (rough grinding process) and polishing process (precision grinding process).The above-mentioned polishing process typically includes pre-grinding process and fine grinding process (final grinding process).As the related technical document of grinding composition mainly used in the purposes of semiconductor substrates such as grinding silicon wafer, patent documentation 1 and 2 can be listed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-89862

[0006] Patent Document 2: Japanese Patent Application Publication No. 2015-124231 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] For the polishing composition used for grinding semiconductor substrates such as silicon wafers and other substrates (for example, the polishing composition used in the fine grinding process), it is required to achieve surface properties with low haze and few surface defects after grinding. The polishing composition contains abrasive grains and water, and also contains a water-soluble polymer for the purpose of protecting the surface of the object to be polished and improving wettability. Among them, as a general water-soluble polymer, cellulose derivatives can be listed.

[0009] However, cellulose derivatives use cellulose, which is a natural product, as a raw material, and therefore, the quality is prone to deviation. Therefore, it is difficult for the polishing composition containing cellulose derivatives in the previous composition to suppress the small aggregation that may cause surface defects with good accuracy. For example, in Patent Documents 1 and 2, for polishing compositions obtained using hydroxyethyl cellulose (HEC), a technology for reducing surface defects is recorded, but sometimes even using this technology, it is not possible to fully cope with the level required for surface quality after polishing in recent years.

[0010] Therefore, an object of the present invention is to provide a method for producing a polishing composition, a method for producing a substrate protective agent, a substrate protective agent, and a polishing composition, which are effective in reducing surface defects after polishing in terms of a composition containing a cellulose derivative.

[0011] Solutions for solving problems

[0012] According to the present specification, a method for producing a polishing composition is provided, wherein the polishing composition comprises abrasive grains, an alkaline compound, a cellulose derivative, and a surfactant. The method for producing the polishing composition comprises: step (A), which dissolves a raw material cellulose derivative in a solvent to produce a raw material cellulose derivative solution, and the method further comprises the following steps: step (B1), which heats the raw material cellulose derivative solution, and step (B2), which adds a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or step (C1), which adds a raw material surfactant to the raw material cellulose derivative solution to produce an additive mixed solution, and step (C2), which heats the additive mixed solution.

[0013] According to the method for producing the polishing composition, it is easy to produce a polishing composition with a reduced number and / or amount of coarse particles derived from a cellulose derivative. According to the polishing composition, the advantages brought by using a cellulose derivative can be utilized, and surface defects (such as LPD-N) after polishing can be effectively reduced.

[0014] In some embodiments, in the step (B2) or the step (C1), the raw material surfactant is added in a state heated to a temperature higher than room temperature. By adding the raw material surfactant heated to an appropriate temperature, the number and / or amount of coarse particles derived from the cellulose derivative can be more easily and more appropriately reduced.

[0015] In addition, according to the present specification, a method for producing a substrate protective agent is provided, wherein the substrate protective agent comprises a cellulose derivative and a surfactant. The method for producing the substrate protective agent comprises: a step (A) of dissolving a raw cellulose derivative in a solvent to produce a raw cellulose derivative solution; the method further comprises the following steps: a step (B1) of heating the raw cellulose derivative solution, and a step (B2) of adding a raw surfactant to the heated raw cellulose derivative solution; or a step (C1) of adding a raw surfactant to the raw cellulose derivative solution to produce an additive mixture, and a step (C2) of heating the additive mixture. According to the method for producing a substrate protective agent of this configuration, it is easy to produce a substrate protective agent in which the number and / or amount of coarse particles derived from cellulose derivatives are reduced. If the substrate protective agent is used, the advantages brought about by the use of cellulose derivatives can be utilized, and surface defects (such as LPD-N) after grinding can be effectively reduced.

[0016] Furthermore, according to the present specification, a substrate protective agent is provided, which comprises a cellulose derivative and a surfactant. The substrate protective agent refers to a group of substances that can adjust the polishing performance of a substrate that is adsorbed at least on the surface of the substrate to be polished when polishing is performed using a polishing composition. The substrate protective agent is prepared by the following method, which includes: step (A), which dissolves a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, and the manufacturing method also includes the following steps: step (B1), which heats the raw material cellulose derivative solution, and step (B2), which adds a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, step (C1), which adds a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and step (C2), which heats the additive mixed solution.

[0017] According to the substrate protective agent of this structure, there is a tendency that the number and / or amount of coarse particles derived from cellulose derivatives in the substrate protective agent is reduced. If the substrate protective agent is used, the advantages brought by using cellulose derivatives can be utilized, and surface defects (such as LPD-N) after grinding can be effectively reduced.

[0018] According to the present specification, a polishing composition is provided, which comprises abrasive grains, an alkaline compound and a substrate protective agent. The substrate protective agent comprises a cellulose derivative and a surfactant, and is prepared by the following method. That is, the substrate protective agent is prepared by the following method, the method comprising: step (A), which dissolves the raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, and the manufacturing method further comprises the following steps: step (B1), which heats the raw material cellulose derivative solution, and step (B2), which adds the raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, step (C1), which adds the raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and step (C2), which heats the additive mixed solution.

[0019] According to the polishing composition, the number and / or amount of coarse particles derived from the cellulose derivative in the composition is reduced, so that the advantages brought by using the cellulose derivative can be utilized and the surface defects after polishing can be effectively reduced. The polishing composition is effective for reducing defects such as LPD-N (Light Point Defect Non-cleanable) that cannot be eliminated by treatment such as polishing, washing, and drying.

[0020] The polishing composition and / or substrate protective agent disclosed herein is preferably used for polishing a surface formed by a silicon material. By using the polishing composition and / or the substrate protective agent to polish a surface formed by a silicon material, a high-quality surface (e.g., a surface with reduced LPD-N) formed by a silicon material can be achieved. In addition, the substrate protective agent disclosed herein is also preferably used for rinsing a surface formed by a silicon material.

[0021] The polishing composition disclosed herein may be a concentrated liquid. The polishing composition disclosed herein may be produced, distributed, and stored in the form of a concentrated liquid.

[0022] In some embodiments, a polishing method is provided, which includes the step of polishing a surface formed of a silicon material using the polishing composition and / or the substrate protective agent. According to the polishing method, a high-quality (eg, LPD-N-reduced) surface formed of a silicon material can be achieved. DETAILED DESCRIPTION

[0023] The following describes a suitable embodiment of the present invention. It should be noted that, in this specification, except for matters specifically mentioned and necessary for implementing the present invention, matters can be regarded as conventional options for those who are aware of the prior art in the field. The present invention can be implemented according to the contents disclosed in this specification and the technical common sense in the field. In addition, unless otherwise specified, in this specification, "room temperature" refers to a temperature above 20°C and below 25°C.

[0024] <Polishing composition, substrate protective agent, and method for producing the same>

[0025] One embodiment of the present invention relates to a substrate protective agent, which comprises a cellulose derivative and a surfactant. In a preferred embodiment, the method for producing the substrate protective agent comprises: step (A), which dissolves a raw material cellulose derivative in water to prepare a raw material cellulose derivative solution; step (B1), which heats the raw material cellulose derivative solution; and step (B2), which adds a raw material surfactant to the raw material cellulose derivative solution after the step (B1).

[0026] In addition, in another preferred embodiment, the method for producing the above-mentioned substrate protective agent includes: step (A), which dissolves the raw cellulose derivative in a solvent to prepare a raw cellulose derivative solution; step (C1), which adds a raw surfactant to the above-mentioned raw cellulose derivative solution to prepare an additive mixed solution; and step (C2), which heats the above-mentioned additive mixed solution.

[0027] Furthermore, one embodiment of the present invention relates to a polishing composition comprising abrasive grains, a basic compound, a cellulose derivative and a surfactant. The polishing composition is characterized in that it comprises a substrate protective agent prepared by any method disclosed herein. In several embodiments, the method for preparing the polishing composition further comprises a step (D) of mixing the substrate protective agent, abrasive grains and a basic compound prepared above.

[0028] The mechanism by which the polishing composition and / or substrate protective agent effective for reducing surface defects after polishing can be obtained according to the present invention is not particularly limited, but can be presumed, for example, as follows.

[0029] In the technology disclosed herein, after a solution containing a raw material cellulose derivative is subjected to a heat treatment, a raw material surfactant can be added to the raw material cellulose derivative solution subjected to the heat treatment. Alternatively, in the technology disclosed herein, a heat treatment can be applied to an additive mixture containing a raw material cellulose derivative and a raw material surfactant. Through the above-mentioned heat treatment, there is a tendency that the hydrogen bonds between the molecules of the raw material cellulose derivative are weakened, and the aggregation or entanglement of the molecules is eliminated. By coexisting with the raw material cellulose derivative and the raw material surfactant in this state, the raw material surfactant acts appropriately on the raw material cellulose derivative to inhibit re-aggregation. According to this treatment, the aggregation or entanglement of the raw material cellulose derivative is eliminated, and then, the re-generation of the aggregate is inhibited, and it is easy to maintain a dispersed state. As a result, the size and / or amount of aggregates originating from the raw material cellulose derivative that may cause surface defects can be suppressed. It can be considered that: according to the polishing composition and / or substrate protective agent, the number of surface defects (such as LPD-N) on the polishing surface can be reduced.

[0030] Hereinafter, the polishing composition and / or substrate protective agent and the method for producing the same will be described, but the present invention is not limited to the following description.

[0031] It should be noted that the polishing composition and / or substrate protective agent disclosed herein comprises a cellulose derivative and a surfactant. In this specification, the cellulose derivative and the surfactant used in the manufacturing process of the polishing composition and / or substrate protective agent are sometimes referred to as "raw material cellulose derivative" and "raw material surfactant", respectively. The "raw material cellulose derivative" in this specification can also be understood as "cellulose derivative", and the "raw material surfactant" can also be understood as "surfactant".

[0032] (Raw material Cellulose derivative)

[0033] The raw material cellulose derivative disclosed herein (or cellulose derivative, the same below) is a polymer containing β-glucose unit as the main repeating unit. Specific examples of raw material cellulose derivatives include hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, etc. The raw material cellulose derivative can be used alone or in combination of two or more. Here, cellulose derivative refers to a substance obtained by replacing a part of the hydroxyl groups possessed by cellulose with other substituents. Among them, from the viewpoint of improving the surface quality after grinding, hydroxyethyl cellulose (HEC) is preferably used as the above-mentioned raw material cellulose derivative.

[0034] Although not particularly limited, the raw material cellulose derivative is preferably a polymer derived from natural products. Since polymers derived from natural products have limitations in terms of purity and foreign matter control, the effects achieved by the technology disclosed herein are easily obtained.

[0035] The weight average molecular weight (Mw) of the raw material cellulose derivative (or cellulose derivative) is not particularly limited. From the perspective of protecting the surface of the polishing object and improving the polishing performance, the Mw of the raw material cellulose derivative (or cellulose derivative) is generally preferably 0.5×10 4 Above, preferably 1×10 4 More preferably, 10×10 4 In a further preferred embodiment, the Mw can be, for example, 15×10 4 Above, it can be 20×10 4 Above, it can be 25×10 4 From the viewpoint of filterability, the Mw of the raw material cellulose derivative (or cellulose derivative) can be set to about 300×10 4 Below, suitable for 150×10 4 The above Mw can be, for example, 100×10 4 Below, it can be 50×10 4 Below, it can be 40×10 4 the following.

[0036] It should be noted that, in this specification, as the Mw of the raw material cellulose derivative (or cellulose derivative), a value based on gel permeation chromatography (GPC) (water system, polyethylene oxide conversion) can be used. As a GPC measuring device, the model name "HLC-8320GPC" manufactured by Tosoh Corporation can be used. The measuring conditions are as follows. The same method can also be used for the examples described below.

[0037] [GPC measurement conditions]

[0038] Sample concentration: 0.1 wt%

[0039] Column: TSKgel GMPWXL

[0040] Detector: Differential Refractometer

[0041] Eluent: 0.1mol / L NaNO3 aqueous solution

[0042] Flow rate: 1.0mL / min

[0043] Measuring temperature: 40℃

[0044] Sample injection volume: 200 μL

[0045] According to one embodiment of the present invention, the content of the raw material cellulose derivative in the raw material cellulose derivative solution is preferably 0.5 wt% or more, more preferably 0.75 wt% or more, and further preferably 1.0 wt% or more. In one embodiment of the present invention, from the viewpoint of solubility, the content of the raw material cellulose derivative in the raw material cellulose derivative solution is preferably 4 wt% or less, more preferably 3 wt% or less, and further preferably 2 wt% or less.

[0046] As the raw material cellulose derivative according to one embodiment of the present invention, it is preferable to use a powdered substance.

[0047] (Raw material surfactant)

[0048] In the manufacturing method of the grinding composition and / or substrate protective agent disclosed herein, a raw material surfactant (or surfactant, the same below) is used. By using a raw material surfactant, there is a tendency to suppress the generation of an association derived from a cellulose derivative and reduce defects (such as LPD-N) on the grinding surface. As a raw material surfactant, anionic, cationic, nonionic, and amphoteric can be used. Generally, anionic or nonionic raw material surfactants can be preferably used. From the viewpoint of reducing haze and low foaming properties and the ease of pH adjustment, nonionic raw material surfactants are more preferred. Examples include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives (e.g., polyoxyalkylene adducts) such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyalkylene alkyl glucosides, polyoxyethylene fatty acid esters, polyoxyethylene glycerol ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; and copolymers of various oxyalkylene groups (e.g., diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers) and other nonionic surfactants. The raw material surfactant may be used alone or in combination of two or more.

[0049] Specific examples of the nonionic surfactant include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide) -PPO (polypropylene oxide) -PEO type triblocks, 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, polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene isostearyl 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, polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene isostearyl ether, polyoxyethylene octyl ether, polyoxyethylene 2-ethylhexyl ether, polyoxyethylene Oxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene methyl glucoside, polyoxypropylene methyl glucoside, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, ethylenediaminetetrapolyoxyethylenepolyoxypropylene (poloxamine), etc. Among them, as preferred surfactants, block copolymers of EO and PO (especially triblock copolymers of PEO-PPO-PEO type), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ether) can be listed. As polyoxyethylene alkyl ethers, polyoxyethylene alkyl ethers having an EO addition molar number of about 1 to 10 (e.g., about 3 to 8) can be preferably used.

[0050] The molecular weight of the raw surfactant (or surfactant) is, for example, less than 5000. From the perspective of reducing the association of cellulose derivatives or filterability, cleaning properties, etc., it is preferably 4500 or less, and for example, it can be less than 4000. In addition, from the perspective of surface activity, etc., the molecular weight of the raw surfactant is usually suitable to be 200 or more, and from the perspective of the effect of reducing haze, etc., it is preferably 250 or more (for example, 300 or more). The more preferred range of the molecular weight of the raw surfactant may also vary depending on the type of the raw surfactant. For example, when polyoxyethylene alkyl ether is used as the raw surfactant, its molecular weight is, for example, preferably less than 2000, more preferably less than 1900 (for example, less than 1800), further preferably less than 1500, and can be less than 1000 (for example, less than 500). In addition, for example, when a block copolymer of EO and PO is used as the raw surfactant, its weight-average molecular weight can be, for example, more than 500, more preferably more than 1000, further more than 1500, more than 2000, and further more than 2500. The upper limit of the weight average molecular weight is, for example, less than 5000, preferably 4500 or less, for example, less than 4000, less than 3800, or less than 3500.

[0051] As the molecular weight of the raw material surfactant (or surfactant), the molecular weight calculated according to the chemical formula can be used, or the value of the weight average molecular weight obtained by GPC (water system, polyethylene glycol conversion) can be used. Regarding the measurement conditions of GPC, the same measurement conditions as those of the above-mentioned cellulose derivatives can be used. For example, in the case of polyoxyethylene alkyl ether, it is preferred to use the molecular weight calculated according to the chemical formula, and in the case of the block copolymer of EO and PO, it is preferred to use the weight average molecular weight obtained by the above-mentioned GPC.

[0052] (Solvent)

[0053] The solvent disclosed herein is not particularly limited as long as it can dissolve the raw material cellulose derivative, and preferably contains water. Preferably, 90% by volume or more of the solvent is water, and more preferably 95% by volume or more (e.g., 99 to 100% by volume) of the solvent is water. As water, ion exchange water (deionized water), pure water, ultrapure water, distilled water, etc. can be preferably used. Regarding the water used, in order to avoid hindering the effects of other components contained in the polishing composition and / or the substrate protective agent as much as possible, the total content of transition metal ions is preferably less than 100 ppb. For example, the purity of water can be improved by removing impurity ions using ion exchange resins, removing foreign matter using filters, distillation, and other operations.

[0054] In addition, the solvent can be an organic solvent or a mixed solvent of water and an organic solvent. As the organic solvent, there is no particular limitation and known organic solvents can be used. When a mixed solvent of water and an organic solvent is used, lower alcohols, lower ketones, etc. as organic solvents miscible with water are preferably used. These organic solvents can be used alone or in combination of two or more.

[0055] <Preparation of Raw Cellulose Derivative Solution (A)>

[0056] The polishing composition and / or substrate protective agent disclosed herein can be produced by a method including step (A), wherein a raw material cellulose derivative solution is prepared by dissolving the raw material cellulose derivative in a solvent. Here, in this specification, "dissolve" means to dissolve or disperse. Moreover, "dissolve" is preferably made into a state where at least a part is dissolved, in which case the remaining part may be dispersed in the solvent, but it is particularly preferably made into a state where it is completely dissolved.

[0057] The method for dissolving the raw material cellulose derivative in the solvent is not particularly limited, but preferably the method of adding the raw material cellulose derivative to the solvent and stirring is performed. The stirring method is not particularly limited, and a known method can be used as appropriate. The stirring time is not particularly limited.

[0058] In addition, the raw cellulose derivative solution may contain an alkaline compound. In this specification, an alkaline compound refers to a compound that has the function of dissolving in water and raising the pH of an aqueous solution. As the alkaline compound, nitrogen-containing organic or inorganic alkaline compounds, alkali metal hydroxides, alkaline earth metal hydroxides, quaternary phosphonium compounds, various carbonates, bicarbonates, etc. can be used. Examples of nitrogen-containing alkaline compounds include quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), etc. Such alkaline compounds can be used alone or in combination of two or more.

[0059] Among these alkaline compounds, at least one alkaline compound selected from alkali metal hydroxides, quaternary ammonium hydroxides and ammonia can be preferably used. Among them, potassium hydroxide, tetraalkylammonium hydroxide (such as tetramethylammonium hydroxide) and ammonia are more preferred, and ammonia is particularly preferred.

[0060] The content of the alkaline compound in the raw cellulose derivative solution is not particularly limited, but is preferably 0.0001% by weight or more, more preferably 0.001% by weight or more, and further preferably 0.01% by weight or more. The content of the alkaline compound in the raw cellulose derivative solution is not particularly limited, but is preferably 10% by weight or less, more preferably 1% by weight or less, and further preferably 0.1% by weight or less. It should be noted that the raw cellulose derivative solution may not contain alkaline compounds.

[0061] <Heating of Raw Cellulose Derivative Solution (B1)>

[0062] In some embodiments, the polishing composition and / or substrate protective agent disclosed herein is produced by a method including the following steps: step (B1) of heating the raw material cellulose derivative solution; and step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1). In this embodiment, the raw material cellulose derivative solution obtained after the step (A) of preparing the raw material cellulose derivative solution is subjected to a heating treatment at an appropriate heating temperature and heating time in step (B1). The heating treatment method is not particularly limited, and a known method can be used as appropriate.

[0063] The heating temperature in the step (B1) is not particularly limited. From the viewpoint of appropriately eliminating the entanglement of the raw material cellulose derivative, the heating temperature in the step (B1) is usually preferably 30°C or higher, preferably 45°C or higher, more preferably 50°C or higher (for example, 55°C or higher), and further preferably 60°C or higher. In addition, the heating temperature in the step (B1) should not exceed the boiling point of the raw material cellulose derivative solution, and is preferably 95°C or lower, more preferably 75°C or lower, and can be 70°C or lower, 65°C or lower, or 60°C or lower.

[0064] The heating time in the above step (B1) is not particularly limited. The heating time in the above step (B1) is the time for maintaining the raw cellulose derivative solution to the above heating temperature. From the viewpoint of appropriately eliminating the entanglement of the raw cellulose derivative, the heating time in the step (B1) is suitably about 20 seconds or more, preferably about 40 seconds or more (for example, more than 1 minute). The upper limit of the heating time in the above step (B1) is not particularly limited. From the viewpoint of manufacturing efficiency, the heating time in the above step (B1) can be set to less than about 180 minutes, can be less than about 60 minutes, and can be less than about 30 minutes.

[0065] <Adding the Raw Material Surfactant (B2) to the Heated Raw Material Cellulose Derivative Solution>

[0066] In step (B2), a raw material surfactant is added to the raw material cellulose derivative solution that has been subjected to a heat treatment in the above-mentioned step (B1). Here, when the raw material surfactant is added, the raw material cellulose derivative solution after the above-mentioned step (B1) may be in a heated state or may be temporarily cooled. That is, in several embodiments, the method for producing a grinding composition and / or a substrate protective agent may include a step (B3) of cooling the raw material cellulose derivative solution after the above-mentioned heating between the above-mentioned step (B1) and the above-mentioned step (B2). In the above-mentioned cooling step (B3), the cooling method of the raw material cellulose derivative solution is not particularly limited, for example, it can be cooled naturally. In addition, the cooling temperature is not particularly limited. For example, the above-mentioned raw material cellulose derivative solution can be cooled to room temperature. From the viewpoint of eliminating the entanglement of the raw material cellulose derivative, in the method for producing a grinding composition and / or a substrate protective agent disclosed herein, when the raw material surfactant is added in step (B2), the raw material cellulose derivative solution after the above-mentioned step (B1) is preferably in a heated state.

[0067] In the above step (B2), when the raw material surfactant is added, the surfactant may be heated to a temperature higher than room temperature or may not be heated. The raw material surfactant heated to a suitable temperature tends to be uniformly dispersed in the liquid and thus easily function as a surfactant. From the viewpoint of further improving the effect of adding the raw material surfactant and suppressing the temperature drop of the raw material cellulose derivative solution after the above step (B1), the raw material surfactant added in the above step (B2) is preferably heated to a temperature higher than room temperature. The temperature of the raw material surfactant added in the above step (B2) can be selected according to the type of the raw material surfactant, and in several embodiments, it is 30°C or more, preferably 35°C or more, and more preferably 40°C or more. The temperature of the raw material surfactant added in the above step (B2) is usually suitable to be 75°C or less, preferably 65°C or less (for example, 60°C or less), and can be 55°C or less, 50°C or less, or 45°C or less.

[0068] In some embodiments, the raw material surfactant is added in the form of a solution to the raw material cellulose derivative solution after the above step (B1). In this embodiment, the content of the raw material surfactant in the above raw material surfactant solution is not particularly limited. From the perspective of operation, the content of the raw material surfactant in the above raw material surfactant solution can be, for example, 0.01 to 100% by weight, preferably 0.1 to 95% by weight, and more preferably 1 to 90% by weight.

[0069] The content of the raw material cellulose derivative in the mixed solution of the raw material cellulose derivative and the surfactant obtained through the above step (B2) is not particularly limited. The content of the raw material cellulose derivative in the above mixed solution can be, for example, 0.1% by weight or more, preferably 0.5% by weight or more, and more preferably 1.0% by weight or more. From the viewpoint of filterability, the content of the raw material cellulose derivative in the above mixed solution is preferably 5% by weight or less, more preferably 4% by weight or less, and further preferably 3% by weight or less.

[0070] The content of the raw material surfactant in the mixed solution of the raw material cellulose derivative and the surfactant obtained through the above step (B2) is not particularly limited. The content of the raw material surfactant in the above mixed solution can be, for example, 0.005% by weight or more, preferably 0.01% by weight or more, and more preferably 0.03% by weight or more from the viewpoint of substrate protection. The content of the raw material surfactant in the above mixed solution is preferably 1% by weight or less, more preferably 0.75% by weight or less, and further preferably 0.5% by weight or less.

[0071] The ratio of the content of the raw material cellulose derivative to the content of the raw material surfactant in the mixed solution of the raw material cellulose derivative and the surfactant obtained through the above step (B2) is not particularly limited. From the viewpoint of substrate protection, the above content ratio is preferably 3.0 or more, more preferably 5.0 or more, further preferably 10 or more, and can be 12 or more, and can be 15 or more. The above content ratio is, for example, 100 or less, preferably 50 or less, more preferably 30 or less, further preferably 25 or less, and can be 20 or less, based on the weight basis.

[0072] The mixed solution of the cellulose derivative and the surfactant prepared in the step (B2) can be used directly as a substrate protective agent. Alternatively, the substrate protective agent can be produced by further diluting, concentrating, adjusting pH, filtering, etc. after the step (B2).

[0073] <Adding the Raw Material Surfactant (C1) to the Raw Material Cellulose Derivative Solution>

[0074] In some embodiments, the polishing composition and substrate protective agent disclosed herein are produced by a method comprising the steps of: (C1) adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution; and (C2) heating the additive mixed solution.

[0075] In the above step (C1), when adding the raw surfactant, the raw surfactant may be heated to a temperature higher than room temperature or may not be heated. The raw surfactant heated to a suitable temperature tends to be uniformly dispersed in the liquid and thus easily function as a surfactant. From the viewpoint of further improving the effect of adding a surfactant, the surfactant added in the above step (C1) is preferably heated to a temperature higher than room temperature. The temperature of the raw surfactant added in the above step (C1) can be selected according to the type of surfactant, and in several embodiments, it is 30°C or more, preferably 35°C or more, and more preferably 40°C or more. The temperature of the surfactant added in the above step (C1) is generally suitable for being below 75°C, preferably below 65°C (for example, below 60°C), can be below 55°C, can be below 50°C, and can be below 45°C.

[0076] In some embodiments, the raw material surfactant is added to the raw material cellulose derivative solution in the form of a solution. In this embodiment, the content of the raw material surfactant in the raw material surfactant solution is not particularly limited. From the perspective of operation, the content of the raw material surfactant in the raw material surfactant solution can be, for example, 0.01 to 100% by weight, preferably 0.1 to 95% by weight, and more preferably 1 to 90% by weight.

[0077] The content of the raw material cellulose derivative in the additive mixed solution prepared in the above step (C1) is not particularly limited. The content of the raw material cellulose derivative in the above additive mixed solution can be, for example, 0.1% by weight or more, preferably 0.5% by weight or more, and more preferably 1.0% by weight or more. From the viewpoint of filterability, the content of the raw material cellulose derivative in the above additive mixed solution is preferably 5% by weight or less, more preferably 4% by weight or less, and even more preferably 3% by weight or less.

[0078] The content of the raw surfactant in the additive mixture prepared in the above step (C1) is not particularly limited. The content of the raw surfactant in the above additive mixture can be, for example, 0.005% by weight or more, preferably 0.01% by weight or more, and more preferably 0.03% by weight or more. From the viewpoint of filterability, the content of the raw surfactant in the above additive mixture is preferably 1% by weight or less, more preferably 0.5% by weight or less (e.g. 0.25% by weight or less), and further preferably 0.1% by weight or less.

[0079] The ratio of the content of the raw material cellulose derivative to the content of the raw material surfactant in the additive mixture prepared in the above step (C1) is not particularly limited. From the viewpoint of substrate protection, the above content ratio is preferably 3.0 or more, more preferably 5.0 or more, further preferably 10 or more, and can be 12 or more, and can be 15 or more. From the viewpoint of improving dispersibility, the above content ratio is, for example, 100 or less, preferably 50 or less, more preferably 30 or less, further preferably 25 or less, and can be 20 or less, based on the weight basis.

[0080] <Heating of Additive Mixture (C2)>

[0081] The additive mixed solution prepared in the above step (C1) is subjected to a heat treatment at an appropriate heating temperature and heating time in step (C2). The heat treatment method is not particularly limited, and a known method can be used as appropriate.

[0082] The heating temperature in the above step (C2) is not particularly limited. From the viewpoint of appropriately eliminating the entanglement of the raw material cellulose derivative, the heating temperature in the step (C2) is usually preferably 30°C or higher, preferably 45°C or higher, more preferably 50°C or higher (for example, 55°C or higher), and further preferably 60°C or higher. In addition, the heating temperature in the step (C2) should not exceed the boiling point of the above-mentioned additive mixed solution, and is preferably 95°C or lower, more preferably 75°C or lower, and can be 70°C or lower, can be 65°C or lower, and can be 60°C or lower.

[0083] The heating time in the above step (C2) is not particularly limited. The heating time is the time for maintaining the additive mixture to the above heating temperature. From the viewpoint of appropriately eliminating the entanglement of the raw cellulose derivative, the heating time in the step (C2) is preferably about 20 seconds or more, preferably about 40 seconds or more (for example, more than 1 minute). The upper limit of the heating time in the above step (C2) is not particularly limited. From the viewpoint of manufacturing efficiency, the heating time in the above step (C2) can be set to less than about 180 minutes, can be less than about 60 minutes, and can be less than about 30 minutes.

[0084] The mixed solution of the cellulose derivative and the surfactant obtained through the above step (C2) can be directly used as the substrate protective agent in the present application. Alternatively, the substrate protective agent can be produced by further diluting, concentrating, adjusting pH, filtering, etc. after the above step (C2).

[0085] <Step (D) of Mixing a Substrate Protecting Agent, Abrasive and Basic Compound>

[0086] The polishing composition disclosed herein includes a substrate protective agent prepared by any method disclosed herein. In some embodiments, the method for producing a polishing composition disclosed herein further includes a step (D) of mixing the substrate protective agent, abrasive grains, and a basic compound.

[0087] The mixing method and mixing conditions of the various components in the above-mentioned mixing step (D) are not particularly limited. For example, other components can be added to the substrate protective agent prepared by any method disclosed herein, and the above-mentioned grinding additives can also be added to other components. In addition, the order of adding the various components is not particularly limited, and they can be added simultaneously, or they can be added sequentially, or only several components can be added simultaneously. There is no particular limitation on the mixing device. For example, a known mixing device such as a wing stirrer, an ultrasonic disperser, a homogenizer, etc. can be used.

[0088] Hereinafter, components contained in the polishing composition and / or the substrate protective agent in several aspects will be described.

[0089] (Abrasive particles)

[0090] The polishing composition disclosed herein contains abrasive grains. The abrasive grains play a role in mechanically polishing the surface of the polishing object. The material and properties of the abrasive grains are not particularly limited and can be appropriately selected according to the purpose of use and the method 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 silicon dioxide particles, aluminum oxide particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and Indian red 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, etc. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles (here (meth)acrylic acid refers to the meaning of covering acrylic acid and methacrylic acid), polyacrylonitrile particles, etc. Such abrasive grains can be used alone or in combination of two or more.

[0091] As the above-mentioned abrasive grains, inorganic particles are preferred, among which particles formed of metal or semimetal oxides are preferred, and silicon dioxide particles are particularly preferred. In the polishing composition that can be used in the polishing (e.g., fine polishing) of a polishing object having a surface formed of silicon, such as a silicon wafer described later, it is particularly meaningful to use silicon dioxide particles as abrasive grains.

[0092] As specific examples of silica particles, colloidal silica, fumed silica, precipitated silica, etc. can be listed. Silica particles can be used alone or in combination of two or more. From the aspect of easily obtaining a grinding surface with excellent surface quality after grinding, colloidal silica is particularly preferably used. As colloidal silica, colloidal silica made from water glass (Na silicate) as a raw material by an ion exchange method, alkoxide method colloidal silica (colloidal silica manufactured by the hydrolysis condensation reaction of alkoxysilane) can be preferably used. Colloidal silica can be used alone or in combination of two or more.

[0093] The true specific gravity of the silicon dioxide constituting the silicon dioxide particles is preferably 1.5 or more, more preferably 1.6 or more, and further preferably 1.7 or more. The upper limit of the true specific gravity of silicon dioxide is not particularly limited, and is typically 2.3 or less, for example, 2.2 or less. As the true specific gravity of the silicon dioxide particles, a measured value based on a liquid substitution method using ethanol as a substitution liquid can be used.

[0094] The average primary particle size of the abrasive (typically, silica particles) is not particularly limited, and from the viewpoint of the grinding rate, it is preferably 5 nm or more, more preferably 10 nm or more. From the viewpoint of obtaining a higher grinding effect (such as reducing haze, removing defects, etc.), the above-mentioned average primary particle size is preferably 15 nm or more, more preferably 20 nm or more (for example, more than 20 nm). In addition, from the viewpoint of preventing scratches, the average primary particle size of the abrasive is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 45 nm or less. From the viewpoint of easily obtaining a surface with lower haze, in several ways, the average primary particle size of the abrasive can be 43 nm or less, less than 40 nm, or less than 38 nm.

[0095] It should be noted that in this specification, the average primary particle size refers to the specific surface area (BET value) measured by the BET method, and the average primary particle size (nm) = 6000 / (true density (g / cm 3 )×BET value (m 2 The above-mentioned specific surface area can be measured using, for example, a surface area measuring device manufactured by Micromeritics, trade name "Flow Sorb II 2300".

[0096] The average secondary particle size of the abrasive (typically, silica particles) is not particularly limited, and can be appropriately selected, for example, from a range of about 15 nm to 300 nm. From the viewpoint of increasing the grinding rate, the above-mentioned average secondary particle size is preferably greater than 30 nm, and more preferably greater than 35 nm. In several embodiments, the above-mentioned average secondary particle size can be, for example, greater than 40 nm, greater than 42 nm, and preferably greater than 44 nm. In addition, it is generally advantageous for the above-mentioned average secondary particle size to be less than 250 nm, preferably less than 200 nm, and more preferably less than 150 nm. In several preferred embodiments, the above-mentioned average secondary particle size is less than 120 nm, more preferably less than 100 nm, and further preferably less than 70 nm.

[0097] It should be noted that, in this specification, the average secondary particle size refers to the particle size (volume average particle size) measured by a dynamic light scattering method. The average secondary particle size of the abrasive can be measured by a dynamic light scattering method using, for example, NANOTRAC UPA-UT151 manufactured by Nikkiso Co., Ltd.

[0098] The shape (outer shape) of the abrasive grains (typically, silica grains) may be spherical or non-spherical. Specific examples of non-spherical grains include peanut-shaped (i.e., peanut shell-shaped), cocoon-shaped, candy-shaped, and rugby-shaped grains. For example, abrasive grains (typically, silica grains) having mostly peanut-shaped or cocoon-shaped grains may be preferably used.

[0099] Although not particularly limited, the average value (average aspect ratio) of the major diameter / minor diameter ratio of the abrasive grains (typically, silica particles) is in principle 1.0 or more, preferably 1.05 or more, more preferably 1.1 or more, and can be 1.2 or more. A higher polishing rate can be achieved by increasing the average aspect ratio. In addition, from the viewpoint of reducing scratches, the average aspect ratio of the abrasive grains (typically, silica particles) is preferably 3.0 or less, more preferably 2.0 or less, more preferably 1.5 or less, and can be 1.4 or less.

[0100] The shape (outer shape) and average aspect ratio of abrasive particles (typically, silica particles) can be grasped by, for example, electron microscope observation. As a specific step to grasp the average aspect ratio, for example, a specified number (e.g., 200) of silica particles whose shapes of independent particles can be identified using a scanning electron microscope (SEM), the smallest rectangle circumscribed to each particle image is drawn. In addition, for the rectangle drawn for each particle image, the value obtained by calculating the length of its long side (the value of the long diameter) divided by the length of the short side (the value of the short diameter) is used as the long diameter / short diameter ratio (aspect ratio). The average aspect ratio can be obtained by arithmetically averaging the aspect ratios of the above-mentioned specified number of particles.

[0101] The polishing composition disclosed herein may contain abrasive grains other than silica grains (hereinafter also referred to as "non-silica abrasive grains") within the range that does not significantly hinder the effect of the present invention. Examples of non-silica abrasive grains include inorganic grains, organic grains, and organic-inorganic composite grains. Specific examples of inorganic grains include oxide grains such as aluminum oxide grains, cerium oxide grains, chromium oxide grains, titanium dioxide grains, zirconium oxide grains, magnesium oxide grains, manganese dioxide grains, zinc oxide grains, and Indian red grains; nitride grains such as silicon nitride grains and boron nitride grains; carbide grains such as silicon carbide grains and boron carbide grains; diamond grains; carbonates such as calcium carbonate and barium carbonate, etc. Specific examples of organic grains include polymethyl methacrylate (PMMA) grains, poly(meth)acrylic acid grains (here, (meth)acrylic acid refers to the meaning of covering acrylic acid and methacrylic acid), and polyacrylonitrile grains. Such abrasive grains may be used alone or in combination of two or more.

[0102] The technology disclosed herein can be preferably implemented in a mode using only silica particles as abrasive particles. From this viewpoint, the proportion of silica particles in the total amount of abrasive particles is preferably 90% by weight or more, preferably 95% by weight or more, and more preferably 98% by weight or more (e.g., 99 to 100% by weight).

[0103] (Basic Compounds)

[0104] The polishing composition disclosed herein comprises a basic compound. In this specification, a basic compound refers to a compound having a function of being dissolved in water and raising the pH of an aqueous solution. If a basic compound is used, the solubility of the water-soluble polymer in the filtration object liquid is easily improved. As the basic compound, nitrogen-containing organic or inorganic basic compounds, alkali metal hydroxides, alkaline earth metal hydroxides, quaternary phosphonium compounds, various carbonates, bicarbonates, etc. can be used. As examples of nitrogen-containing basic compounds, quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), etc. can be listed. This basic compound can be used alone or in combination of two or more.

[0105] Among these alkaline compounds, at least one alkaline compound selected from alkali metal hydroxides, quaternary ammonium hydroxides and ammonia can be preferably used. Among them, potassium hydroxide, tetraalkylammonium hydroxide (such as tetramethylammonium hydroxide) and ammonia are more preferred, and ammonia is particularly preferred.

[0106] (water)

[0107] Typically, the polishing composition disclosed herein contains water. As the water contained in the polishing composition, ion exchange water (deionized water), pure water, ultrapure water, distilled water, etc. can be preferably used. Regarding the water used, in order to avoid the effects of other components contained in the polishing composition being hindered as much as possible, the total content of transition metal ions, for example, is preferably less than 100 ppb. For example, the purity of water can be improved by removing impurity ions using ion exchange resins, removing foreign matter using filters, and distilling operations. It should be noted that the polishing composition disclosed herein may also contain an organic solvent (lower alcohol, lower ketone, etc.) that can be uniformly mixed with water as needed. More than 90% by volume of the solvent contained in the polishing composition is preferably water, and more preferably more than 95% by volume (for example, 99 to 100% by volume) is water.

[0108] (Water-soluble polymer)

[0109] The polishing composition disclosed herein includes a cellulose derivative as a water-soluble polymer. The cellulose derivative may be included in a substrate protective agent prepared by any method disclosed herein. There is no particular limitation on the type and weight average molecular weight (Mw) of the cellulose derivative included in the polishing composition, and it may be appropriately selected from the same range as the type and weight average molecular weight (Mw) of the raw material cellulose derivative. One cellulose derivative may be used alone or two or more cellulose derivatives may be used in combination.

[0110] The polishing composition and / or substrate protective agent disclosed herein may contain any water-soluble polymer other than cellulose derivatives within the range that does not significantly impair the effect of the present invention. The type of any water-soluble polymer is not particularly limited, and a substance having at least one functional group selected from a cationic group, an anionic group and a nonionic group may be used. Any water-soluble polymer may have a hydroxyl group, a carboxyl group, an acyl group, an acyloxy group, a sulfonic group, an amide group, a quaternary ammonium structure, a heterocyclic structure, a vinyl structure, a polyoxyalkylene structure, etc.

[0111] As examples of arbitrary water-soluble polymers, there can be cited: starch derivatives; polymers containing oxyalkylene units such as copolymers of ethylene oxide (EO) and propylene oxide (PO); vinyl alcohol polymers such as polyvinyl alcohol (PVA); polymers containing N-vinyl monomer units, imine derivatives, polymers containing N-(meth)acryloyl monomer units, and other polymers containing nitrogen atoms. From the viewpoint of being able to improve the grinding performance by being used in a grinding composition, as arbitrary water-soluble polymers, vinyl alcohol polymers and polymers containing N-(meth)acryloyl monomer units are preferred. Any water-soluble polymer can be used alone or in combination of two or more. From the viewpoint of simplifying the composition, the grinding composition and / or substrate protective agent disclosed herein may not contain any water-soluble polymer other than cellulose derivatives.

[0112] (Surfactant)

[0113] The polishing composition disclosed herein includes a surfactant. The above-mentioned surfactant may be included in a substrate protective agent prepared by any method disclosed herein. There is no particular limitation on the type and weight average molecular weight (Mw) of the surfactant included in the polishing composition, and it can be appropriately selected from the same range as the type and weight average molecular weight (Mw) of the above-mentioned raw material surfactant. The surfactant may be used alone or in combination of two or more.

[0114] (Other ingredients)

[0115] The polishing composition disclosed herein may further contain known additives that can be used in polishing compositions (e.g., polishing compositions used in the fine polishing process of silicon wafers), such as organic acids, organic acid salts, inorganic acids, inorganic acid salts, chelating agents, preservatives, and mildew inhibitors, as needed, within the range that does not significantly hinder the effects of the present invention.

[0116] Organic acids and their salts, as well as inorganic acids and their salts can be used alone or in combination of two or more. 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; organic sulfonic acids such as 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, hydroxyethylidene diphosphonic acid (HEDP), and methanesulfonic acid; organic phosphonic acids such as nitrilotri(methylenephosphonic acid) (NTMP) and phosphobutane tricarboxylic acid (PBTC). Examples of organic acid salts include alkali metal salts (sodium salts, potassium salts, lithium 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, and carbonic acid. Examples of inorganic acid salts include alkali metal salts (sodium salts, potassium salts, lithium salts, etc.) and ammonium salts of inorganic acids.

[0117] The above-mentioned chelating agent may be used alone or in combination of two or more. Examples of the above-mentioned 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 above-mentioned preservatives and mildewproofing agents include isothiazolin compounds, parabens, phenoxyethanol, etc.

[0118] The polishing composition disclosed herein is preferably substantially free of oxidant. This is because: if the polishing composition includes an oxidant, the surface of the substrate is oxidized and an oxide film is produced due to the polishing composition being supplied to the substrate (such as a silicon wafer), and thus, the polishing rate may sometimes be reduced. As a specific example of the oxidant mentioned here, hydrogen peroxide (H2O2), sodium persulfate, ammonium persulfate, sodium dichloroisocyanurate, etc. can be listed. It should be noted that the polishing composition substantially does not contain an oxidant, which means that at least it does not actively contain an oxidant. Therefore, the polishing composition that is derived from raw materials, preparation methods, etc. and inevitably contains a trace amount (for example, the molar concentration of the oxidant in the polishing composition is 0.001 mol / L or less, preferably 0.0005 mol / L or less, more preferably 0.0001 mol / L or less, further preferably 0.00005 mol / L or less, particularly preferably 0.00001 mol / L or less) of an oxidant is included in the concept of the polishing composition substantially free of oxidant mentioned here.

[0119] <ph>

[0120] The pH of the polishing composition disclosed herein is not particularly limited, and an appropriate pH can be adopted according to the substrate, etc. In several ways, the pH of the polishing composition is suitable for more than 8.0, preferably more than 8.5, and more preferably more than 9.0. If the pH of the polishing composition becomes high, there is a tendency for the polishing rate to increase. On the other hand, from the viewpoint of preventing the dissolution of silicon dioxide particles and suppressing the reduction of mechanical polishing, the pH of the polishing composition is usually suitable for less than 12.0, preferably less than 11.0, more preferably less than 10.8, and more preferably less than 10.5.

[0121] It should be noted that in the technology disclosed herein, the pH of the polishing composition can be determined by the following operation: using a pH meter (e.g., a glass electrode type hydrogen ion concentration indicator (model: F-72) manufactured by Horiba, Ltd.), after performing a three-point calibration using a standard buffer solution (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)), the glass electrode is placed in the composition to be measured, and after stabilization for more than 2 minutes, the value is measured to determine the pH.

[0122] <Substrate Protective Agent>

[0123] The substrate protective agent disclosed herein refers to a group of substances that can adjust the polishing performance of a substrate by adsorbing at least to the surface of the substrate to be polished when polishing with a polishing composition, specifically, a cellulose derivative and a surfactant. Here, the cellulose derivative contained in the substrate protective agent has a tendency to have a reduced size and / or amount of the association and improved dispersibility compared to the raw cellulose derivative. Therefore, the light transmittance of the substrate protective agent is easily improved. Although not particularly limited, the visible light transmittance of the substrate protective agent disclosed herein is preferably 85% or more, more preferably 90% or more (for example, 92% or more), and further preferably 95% or more (for example, 98% or more). The upper limit of the visible light transmittance of the substrate protective agent is not particularly limited. In principle, the visible light transmittance of the substrate protective agent is less than 100%, and can be less than 99%. It should be noted that the visible light transmittance is the average transmittance of visible light in the wavelength range of 380 to 780 nm.

[0124] The content of the cellulose derivative in the substrate protective agent disclosed herein is not particularly limited. The content of the cellulose derivative in the above-mentioned substrate protective agent can be set to, for example, 0.0001% by weight or more, preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, and further preferably 0.003% by weight or more, and can be 0.005% by weight or more, and can be 0.01% by weight or more, and can be 0.05% by weight or more, and can be 0.1% by weight or more, and can be 0.5% by weight or more, and can be 1.0% by weight or more. The content of the cellulose derivative in the above-mentioned substrate protective agent is preferably 5% by weight or less, and more preferably 4% by weight or less, and further preferably 3% by weight or less, and can be 1% by weight or less, and can be 0.5% by weight or less, and can be 0.1% by weight or less, and can be 0.05% by weight or less, and can be 0.01% by weight or less, and can be 0.008% by weight or less.

[0125] The content of the surfactant in the substrate protective agent is not particularly limited. The content of the surfactant in the above-mentioned substrate protective agent can be set to, for example, 0.00005% by weight or more, preferably 0.0001% by weight or more, more preferably 0.0003% by weight or more, further preferably 0.0005% by weight or more, can be 0.0008% by weight or more, can be 0.001% by weight or more, can be 0.005% by weight or more, can be 0.01% by weight or more, can be 0.03% by weight or more. The content of the surfactant in the above-mentioned substrate protective agent is preferably 1% by weight or less, more preferably 0.5% by weight or less (for example, 0.25% by weight or less), further preferably 0.1% by weight or less, can be 0.05% by weight or less, can be 0.03% by weight or less, can be 0.01% by weight or less, can be 0.005% by weight or less, can be 0.003% by weight or less.

[0126] <Polishing fluid>

[0127] Typically, the grinding composition disclosed herein is supplied to the surface of the substrate in the form of a grinding liquid containing the grinding composition, and is used for the grinding of the substrate. The above-mentioned grinding liquid can be prepared by, for example, diluting any grinding composition disclosed herein (typically, diluting with water). Alternatively, the grinding composition can be directly used as a grinding liquid. As other examples of the grinding liquid containing the grinding composition disclosed herein, a grinding liquid formed by adjusting the pH of the composition can be listed.

[0128] The content of abrasive grains (typically, silica particles) in the polishing liquid is not particularly limited, for example, more than 0.001 weight %, preferably more than 0.05 weight %, more preferably more than 0.10 weight %. By increasing the content of abrasive grains, a higher polishing rate can be achieved. The above content is suitable for less than 10 weight %, preferably less than 7 weight %, more preferably less than 5 weight %, further preferably less than 2 weight %, for example, less than 1 weight %, less than 0.75 weight %, less than 0.5 weight %. Thus, it is easy to achieve the maintenance of surface quality.

[0129] The content of the basic compound in the polishing liquid is not particularly limited. From the viewpoints such as improving the polishing rate, it is usually suitable to set the above-mentioned content to more than 0.0005 weight %, preferably to more than 0.001 weight %, and further preferably to more than 0.003 weight %. In addition, from the viewpoints such as improving surface quality (such as reducing haze), it is suitable to set the above-mentioned content to less than 0.1 weight %, preferably to less than 0.05 weight %, and more preferably to less than 0.03 weight % (for example, less than 0.025 weight %, and then less than 0.01 weight %).

[0130] The content of the cellulose derivative in the polishing liquid is not particularly limited. For example, it can be set to 0.0001% by weight or more. From the viewpoint of reducing haze, the content is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, and further preferably 0.002% by weight or more, for example 0.005% by weight or more. In addition, from the viewpoint of polishing rate, the above content is preferably set to 0.2% by weight or less, more preferably 0.1% by weight or less, and further preferably 0.05% by weight or less (for example 0.02% by weight or less, and further 0.015% by weight or less).

[0131] In the case where the polishing liquid contains any water-soluble polymer other than a cellulose derivative, the total content of the water-soluble polymer in the polishing liquid is not particularly limited. For example, it can be set to 0.0001% by weight or more. From the viewpoint of reducing haze, the preferred content is 0.0005% by weight or more, more preferably 0.001% by weight or more, and further preferably 0.002% by weight or more, for example, 0.005% by weight or more. In addition, from the viewpoint of polishing rate, it is preferred that the above content is set to 0.2% by weight or less, more preferably 0.1% by weight or less, and further preferably 0.05% by weight or less (for example, 0.02% by weight or less, and further 0.015% by weight or less).

[0132] The content of the surfactant in the polishing liquid is not particularly limited. Usually, from the viewpoint of improving the dispersibility and cleaning properties of the cellulose derivative, the content of the above-mentioned surfactant can be set to, for example, 0.00001% by weight or more. From the viewpoint of reducing the haze, the content is preferably 0.0002% by weight or more, more preferably 0.0003% by weight or more, and further preferably 0.0005% by weight or more. In addition, from the viewpoint of the polishing rate, the above-mentioned content is preferably set to 0.1% by weight or less, more preferably 0.01% by weight or less, and further preferably 0.005% by weight or less (for example, 0.002% by weight or less).

[0133] <Concentrate>

[0134] The grinding composition disclosed herein can be in a concentrated form (i.e., a concentrated liquid form of the grinding liquid) before being supplied to the substrate. The grinding composition in this concentrated form is advantageous from the viewpoints of convenience, cost reduction, etc. during manufacture, circulation, preservation, etc. The concentration ratio is not particularly limited, for example, it can be set to about 2 times to 100 times in terms of volume conversion, usually about 5 times to 50 times (e.g., about 10 times to 40 times). This concentrated solution can be prepared by diluting the grinding liquid (working slurry) at a desired time, and the grinding liquid is supplied to the substrate for use. The above-mentioned dilution can be carried out by, for example, adding water to the above-mentioned concentrated solution and mixing.

[0135] When the polishing composition (i.e., concentrated solution) is diluted and used for polishing, the abrasive content in the concentrated solution can be set to, for example, 25% by weight or less. From the viewpoints of dispersion stability and filterability of the polishing composition, the above content is usually preferably 20% by weight or less, and more preferably 15% by weight or less. In several preferred embodiments, the abrasive content can be set to 10% by weight or less, and can be set to 5% by weight or less. In addition, from the viewpoints of convenience during manufacture, circulation, storage, etc., cost reduction, etc., the abrasive content in the concentrated solution can be set to, for example, 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 0.7% by weight or more, and further preferably 1% by weight or more.

[0136] In some embodiments, the content of the alkaline compound in the above-mentioned concentrated solution can be set to, for example, less than 15% by weight. From the viewpoint of storage stability, the above-mentioned content is usually preferably 0.7% by weight or less, and more preferably 0.4% by weight or less. In addition, from the viewpoint of convenience during manufacture, circulation, storage, etc., cost reduction, etc., the content of the alkaline compound in the concentrated solution can be set to, for example, 0.005% by weight or more, preferably 0.01% by weight or more, more preferably 0.02% by weight or more, and further preferably 0.05% by weight or more.

[0137] In some embodiments, the content of the cellulose derivative in the concentrated solution can be set to 3% by weight or less, for example. From the viewpoint of filterability and washability of the polishing composition, the above content is usually preferably 1% by weight or less, and more preferably 0.5% by weight or less. In addition, from the viewpoint of convenience during manufacture, circulation, storage, etc., and cost reduction, the above content is usually preferably 0.001% by weight or more, preferably 0.005% by weight or more, and more preferably 0.01% by weight or more.

[0138] In some embodiments, the content of the surfactant in the concentrated solution can be, for example, 0.25% by weight or less, preferably 0.15% by weight or less, more preferably 0.1% by weight or less, 0.05% by weight or less, or 0.025% by weight or less. In addition, the content of the surfactant in the concentrated solution can be, for example, 0.0001% by weight or more, preferably 0.001% by weight or more, more preferably 0.005% by weight or more, and even more preferably 0.01% by weight or more.

[0139] <Purpose>

[0140] The polishing composition and / or substrate protective agent disclosed herein can be applied to the polishing of substrates having various materials and shapes. The material of the substrate can be, for example, metals or semi-metals such as silicon materials, aluminum, nickel, tungsten, copper, tantalum, titanium, stainless steel, or their alloys; glassy substances such as quartz glass, aluminosilicate glass, and glassy carbon; ceramic materials such as aluminum oxide, silicon dioxide, sapphire, silicon nitride, tantalum nitride, and titanium carbide; compound semiconductor substrate materials such as silicon carbide, gallium nitride, and gallium arsenide; resin materials such as polyimide resin, etc. The substrate can be composed of a variety of materials among these. The shape of the substrate is not particularly limited. The polishing composition disclosed herein can be applied to the polishing of substrates having a flat surface such as a plate or a polyhedron, or the polishing of the end of the substrate (such as the polishing of the edge of a wafer). In several ways, the substrate protective agent disclosed herein can also be used for rinsing the above-mentioned substrate.

[0141] The polishing composition and / or substrate protective agent disclosed herein can be particularly preferably used for polishing a surface formed by a silicon material (typically, polishing a silicon wafer). As specific examples of silicon materials, silicon single crystals, amorphous silicon, and polycrystalline silicon can be cited. The polishing composition disclosed herein can be particularly preferably used for polishing a surface formed by a silicon single crystal (e.g., polishing a silicon wafer). In several embodiments, the substrate protective agent disclosed herein can also be applied to the rinsing of the above-mentioned substrate.

[0142] The grinding composition disclosed herein and / or substrate protective agent can be preferably applied to the polishing process of substrate (e.g., silicon wafer). The substrate can be subjected to general treatments such as grinding and etching that can be applied to the substrate in the process further upstream of the polishing process before the polishing process performed by the grinding composition disclosed herein.

[0143] The grinding composition and / or substrate protective agent disclosed herein is effective in the finishing process of the substrate (e.g., silicon wafer) or in the polishing process immediately before it, and is particularly preferably used in the fine polishing process. Here, the fine polishing process refers to the last polishing process in the manufacturing process of the target object (i.e., a process in which no further polishing is performed after this process). In addition, the grinding composition disclosed herein can also be used in a polishing process upstream of the fine polishing (referring to a pre-grinding process between a rough grinding process and a final grinding process. Typically, it includes at least one polishing process, and can further include 2, 3, etc. polishing processes), for example, it can be used in a polishing process performed immediately before the fine polishing.

[0144] The polishing composition and / or substrate protective agent disclosed herein are effective in the polishing (typically, fine polishing or polishing immediately before) of a silicon wafer having a surface state of 0.01 nm to 100 nm prepared by an upstream process. It is particularly preferably applied to fine polishing. The surface roughness Ra of the substrate can be measured using a laser scanning surface roughness meter "TMS-3000WRC" made by Schmitt Measurement System Inc., for example.

[0145] The polishing composition used in the technology disclosed herein can be a single component type or a multi-component type headed by a two-component type. For example, it can be constructed in the following manner: a portion A containing at least abrasive grains among the constituent components of the polishing composition is mixed with a portion B containing at least a portion of the remaining components, and they are mixed and diluted at an appropriate time as needed to prepare a polishing liquid. Part B can be any substrate protective agent disclosed herein. Part A can be filtered once or twice or more.

[0146] <Grinding>

[0147] The polishing composition and / or substrate protective agent disclosed herein can be used for polishing a substrate by, for example, a method including the following operations. A suitable method of polishing a silicon wafer as a substrate using the polishing composition disclosed herein is described below.

[0148] That is, a polishing liquid containing any polishing composition or substrate protective agent disclosed herein is prepared. Regarding the preparation of the above-mentioned polishing liquid, on the basis of operations such as concentration adjustment (e.g., dilution) and pH adjustment of the polishing composition, the polishing liquid may also be prepared. Alternatively, the polishing composition may be directly used as a polishing liquid.

[0149] Next, the polishing liquid is supplied to the substrate and polished by conventional methods. For example, in the case of fine polishing of a silicon wafer, typically, the silicon wafer after the grinding process is placed in a general polishing device, and the polishing liquid is supplied to the polishing target surface of the silicon wafer through the polishing pad of the polishing device. Typically, the polishing liquid is continuously supplied, and the polishing pad is pressed against the polishing target surface of the silicon wafer, so that the two move relative to each other (for example, rotate). After this polishing process, the polishing of the substrate is completed.

[0150] The grinding pad used in the above-mentioned grinding process is not particularly limited. For example, a grinding pad of a foamed polyurethane type, a nonwoven type, a suede type, etc. can be used. Each grinding pad can contain abrasive particles or can contain no abrasive particles. Usually, a grinding pad that does not contain abrasive particles is preferably used.

[0151] Typically, the substrate polished using the polishing composition disclosed herein is to be cleaned. Cleaning can be performed using an appropriate cleaning solution. The cleaning solution used is not particularly limited, and for example, SC-1 cleaning solution (a mixture of ammonium hydroxide (NH4OH) and hydrogen peroxide (H2O2) and water (H2O)), SC-2 cleaning solution (a mixture of HCl and H2O2 and H2O), ozone water cleaning solution, hydrofluoric acid cleaning solution, etc. commonly used in the fields of semiconductors, etc. can be used. The temperature of the cleaning solution can be set, for example, to a range of above room temperature (typically, about 15°C to 25°C) to about 90°C. From the viewpoint of improving the cleaning effect, a cleaning solution of about 50°C to 85°C can be preferably used.

[0152] As described above, the technology disclosed herein includes providing a method for manufacturing a polished article (eg, a method for manufacturing a silicon wafer) and a polished article (eg, a silicon wafer) manufactured by the method, wherein the method for manufacturing a polished article includes a polishing step based on any of the above-mentioned polishing methods.

[0153] Matters disclosed by this specification include the following technical solutions.

[0154] [1] A method for producing a polishing composition, wherein the polishing composition comprises abrasive grains, a basic compound, a cellulose derivative and a surfactant,

[0155] The manufacturing method comprises:

[0156] step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution,

[0157] The manufacturing method also includes the following steps:

[0158] A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1);

[0159] or,

[0160] A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

[0161] [2] The method for producing a polishing composition according to [1] above, wherein in the step (B2) or the step (C1), the raw material surfactant is added in a state heated to a temperature higher than room temperature.

[0162] [3] A method for producing a substrate protective agent, wherein the substrate protective agent comprises a cellulose derivative and a surfactant,

[0163] The manufacturing method comprises:

[0164] step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution,

[0165] The manufacturing method also includes the following steps:

[0166] A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1);

[0167] or,

[0168] A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

[0169] [4] A substrate protective agent comprising a cellulose derivative and a surfactant, wherein the substrate protective agent is prepared by the following method:

[0170] The method comprises:

[0171] step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution,

[0172] The method also includes the following steps:

[0173] A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1);

[0174] or,

[0175] A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

[0176] [5] A polishing composition comprising abrasive grains, a basic compound and a substrate protective agent,

[0177] The substrate protective agent comprises a cellulose derivative and a surfactant,

[0178] Here, the aforementioned substrate protective agent is prepared by the following method:

[0179] The method comprises:

[0180] step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution,

[0181] The method also includes the following steps:

[0182] A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1);

[0183] or,

[0184] A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

[0185] [6] The polishing composition according to [5] above, which is used for polishing a surface formed of a silicon material.

[0186] [7] A concentrated solution which is a concentrated solution of the polishing composition according to [5] or [6].

[0187] [8] A polishing method comprising the step of polishing a surface formed of a silicon material using the polishing composition according to any one of [5] to [7] above.

[0188] [9] A polishing composition comprising abrasive grains, a basic compound and a substrate protective agent,

[0189] The substrate protective agent comprises a cellulose derivative and a surfactant,

[0190] The substrate protective agent has a visible light transmittance of 85% or more.

[0191] Example

[0192] Hereinafter, several embodiments related to the present invention are described, but it is not intended that the present invention is limited to the scope shown in the embodiments. It should be noted that in the following description, "parts" and "%" are weight references unless otherwise specified.

[0193] <Test Example 1>

[0194] <Preparation of substrate protective agent>

[0195] (Example 1)

[0196] [Dissolution of raw material HEC]

[0197] At room temperature, deionized water (DIW) was added to a glass beaker, and a powder of raw material hydroxyethyl cellulose (hereinafter referred to as "raw material HEC") having a weight average molecular weight (Mw) of 280,000 was added and dissolved while stirring. Thereafter, ammonia water was added to prepare a raw material hydroxyethyl cellulose aqueous solution (hereinafter referred to as "raw material HEC aqueous solution") having a raw material HEC concentration of 1.3% and an ammonia concentration of 0.01%.

[0198] [Heating of raw material HEC aqueous solution]

[0199] 100 mL of the obtained raw material HEC aqueous solution was heated and maintained at 60° C. for 1 minute.

[0200] [Addition of raw material surfactant]

[0201] For the above-mentioned heated raw material HEC aqueous solution 100mL, the raw material surfactant (1% aqueous solution) heated to 43°C was added and stirred, and then naturally cooled to room temperature, thereby obtaining the substrate protective agent described in this example with a hydroxyethyl cellulose concentration of 1.2% and a raw material surfactant concentration of 0.067%. As the raw material surfactant, polyoxyethylene decyl ether (C10PEO5) with a weight average molecular weight (Mw) of 378 and an ethylene oxide addition mole number of 5 was used.

[0202] (Examples 2 to 10)

[0203] Except that the heating temperature and heating time of the raw material HEC aqueous solution in [Heating of raw material HEC aqueous solution] of Example 1 were changed as shown in Table 1, the same operation as in Example 1 was carried out to prepare the substrate protective agent described in each example.

[0204] (Example 11)

[0205] In [Heating of the raw HEC aqueous solution] of Example 1, the raw HEC aqueous solution was heated and maintained at 60° C. for 30 minutes. Thereafter, the raw HEC aqueous solution was naturally cooled to room temperature, and a raw surfactant (1% aqueous solution) heated to 43° C. was added to the raw HEC aqueous solution at room temperature. The substrate protective agent described in this example was prepared in the same manner as in Example 1 except that the raw HEC aqueous solution was heated to 43° C.

[0206] (Example 12)

[0207] The raw HEC aqueous solution was prepared in the same manner as in [Dissolution of raw HEC] of Example 1. A raw surfactant (1% aqueous solution) heated to 43°C was added to the obtained raw HEC aqueous solution and stirred, and the obtained mixed solution was heated and maintained at 60°C for 30 minutes. Thereafter, the heated mixed solution was naturally cooled to room temperature, thereby obtaining the substrate protective agent described in this example having a hydroxyethyl cellulose concentration of 1.2% and a surfactant concentration of 0.067%. As the raw surfactant, polyoxyethylene decyl ether (C10PEO5) having a weight average molecular weight (Mw) of 378 and an ethylene oxide addition mole number of 5 was used in the same manner as in Example 1.

[0208] (Example 13)

[0209] The substrate protective agent described in this example was prepared in the same manner as in Example 1, except that the heating time of the raw HEC aqueous solution in [Heating of the raw HEC aqueous solution] in Example 1 was changed as shown in Table 1, and in [Addition of the raw surfactant] in Example 1, a raw surfactant (1% aqueous solution) at room temperature (i.e., not heated) was added to the heated raw HEC aqueous solution.

[0210] (Comparative Example 1)

[0211] [Heating of raw material HEC aqueous solution]

[0212] At room temperature, deionized water (DIW) was added to a glass beaker, and a powder of raw material hydroxyethyl cellulose (raw material HEC) having a weight average molecular weight (Mw) of 280,000 was added and dissolved while stirring. Thereafter, ammonia water was added to prepare a raw material HEC aqueous solution having a raw material HEC concentration of 1.3% and an ammonia concentration of 0.01%.

[0213] [Addition of raw material surfactant]

[0214] 100 mL of the obtained raw HEC aqueous solution (i.e., unheated raw HEC aqueous solution) was added with a raw surfactant (1% aqueous solution) heated to 43°C and stirred, and then naturally cooled to room temperature, thereby obtaining the substrate protective agent described in this example having a hydroxyethyl cellulose concentration of 1.2% and a surfactant concentration of 0.067%. As the raw surfactant, polyoxyethylene decyl ether (C10PEO5) having a weight average molecular weight (Mw) of 378 and an ethylene oxide addition mole number of 5 was used in the same manner as in Example 1.

[0215] (Comparative Example 2)

[0216] In [Addition of raw material surfactant] in Comparative Example 1, the substrate protective agent described in this example was obtained by the same operation as in Comparative Example 1, except that a raw material surfactant (1% aqueous solution) at room temperature (i.e., unheated) was added to the raw HEC aqueous solution (i.e., unheated raw HEC aqueous solution).

[0217] <Evaluation of transmittance>

[0218] The average transmittance of the substrate protective agent described in each example in the wavelength range of 380 to 780 nm was measured using an ultraviolet visible spectrophotometer (manufactured by Shimadzu Corporation, model "UV-2450"). The above measurement was performed one day after the substrate protective agent described in each example was prepared. The measurement conditions are shown below.

[0219] [Measurement conditions]

[0220] Concentration of the measured sample: Hydroxyethyl cellulose 1.2%, surfactant 0.067%

[0221] The amount of sample to be measured: 10 g

[0222] Determine the sample temperature: room temperature

[0223] Scanning speed: medium speed

[0224] Sampling spacing: 1nm

[0225] Slit width: 2mm

[0226] The obtained transmittance was evaluated in the following three stages and the results are shown in the corresponding columns of Table 1.

[0227] Transmittance is above 95%: E (excellent)

[0228] Transmittance is 85% or more and less than 95%: G (good)

[0229] Transmittance less than 85%: P (poor)

[0230] [Table 1]

[0231] Table 1

[0232]

[0233] According to the results shown in Table 1, it is clear that the substrate protective agents of Examples 1 to 10 and 13 prepared by adding the raw surfactant to the heated raw HEC aqueous solution, the substrate protective agent of Example 11 prepared by adding the raw surfactant after the heated raw HEC aqueous solution was cooled to room temperature, and the substrate protective agent of Example 12 prepared by mixing the unheated raw HEC aqueous solution with the raw surfactant and then heating the mixed solution all have higher transmittance than the substrate protective agents of Comparative Examples 1 and 2 prepared by mixing the raw HEC aqueous solution with the raw surfactant. In particular, the substrate protective agents of Examples 1 to 7 in which the heating temperature of the raw HEC aqueous solution was set to 60°C or above showed more excellent transmittance. It is believed that the high transmittance is due to the reduction in the size or amount of the HEC aggregate in the substrate protective agent.

[0234] In addition, when adding the raw material surfactant, by comparing Example 3 obtained using the raw material surfactant heated to 43°C with Example 13 obtained using the raw material surfactant at room temperature, it can be determined that by using a heated surfactant, there is a tendency for the transmittance of the substrate protective agent to increase.

[0235] <Test Example 2>

[0236] <Preparation of Polishing Composition>

[0237] (Example 14)

[0238] The substrate protective agent described in Example 3 of Test Example 1 was prepared. In addition, abrasive grains were mixed with ammonia and deionized water to prepare an abrasive grain-containing liquid. As abrasive grains, colloidal silica having an average primary particle size of 35 nm was used. The abrasive grain-containing liquid was mixed with the substrate protective agent described in Example 3 of Test Example 1 to prepare a concentrated polishing composition described in this example.

[0239] The polishing composition described in this example is obtained by diluting the obtained concentrated polishing composition with deionized water to a volume ratio of 20 times, thereby obtaining a polishing composition with an abrasive content of 0.125%, an ammonia content of 0.0050%, a hydroxyethyl cellulose (HEC) content of 0.0100%, and a polyoxyethylene decyl ether (C10PEO5) content of 0.0005%.

[0240] (Comparative Example 3)

[0241] A polishing composition according to this example was prepared in the same manner as in Example 14, except that the substrate protective agent described in Comparative Example 1 of Test Example 1 was used instead of the substrate protective agent described in Example 3 of Test Example 1.

[0242] <Evaluation of Surface Quality of Polished Surface>

[0243] (Silicon wafer grinding)

[0244] As a substrate, a commercially available silicon single crystal wafer (conductivity type: P type, crystal orientation: <100> , COP-free silicon wafer pre-polished under the following polishing condition 1. The pre-polishing was performed using a polishing liquid containing 1.0% abrasive grains (colloidal silica with an average primary particle size of 35 nm) and 0.068% potassium hydroxide in deionized water.

[0245] [Grinding Condition 1]

[0246] Grinding device: Single-wafer grinding device model "PNX-332B" manufactured by Okamoto Machine Tool Co., Ltd.

[0247] Grinding load: 20kPa

[0248] Platform rotation speed: 20rpm

[0249] Head (carrier) rotation speed: 20rpm

[0250] Polishing pad: Made by NITTA DuPont, product name "SUBA400"

[0251] Grinding liquid supply rate: 1.0L / min

[0252] Grinding fluid temperature: 20°C

[0253] Platform cooling water temperature: 20℃

[0254] Grinding time: 3 minutes

[0255] The silicon wafer after the preliminary polishing was polished under the following polishing conditions 2 using the polishing composition described in each example prepared above as a polishing liquid, and then polished under polishing conditions 3.

[0256] [Grinding Condition 2]

[0257] Grinding device: Single-wafer grinding device model "PNX-332B" manufactured by Okamoto Machine Tool Co., Ltd.

[0258] Grinding load: 16kPa

[0259] Rotation speed of the platen: 50 rpm

[0260] Rotation speed of the head (carrier): 52 rpm

[0261] Polishing pad: Product name "POLYPAS275NX" manufactured by FUJIBO EHIME Co., Ltd.

[0262] Supply rate of the polishing liquid: 1.5 L / minute

[0263] Temperature of the polishing liquid: 20 °C

[0264] Temperature of the platen cooling water: 20 °C

[0265] Polishing time: 4 minutes

[0266] [Polishing condition 3]

[0267] Polishing apparatus: Single wafer polishing apparatus model "PNX-332B" manufactured by Okamoto Machine Works, Ltd.

[0268] Polishing load: 20 kPa

[0269] Rotation speed of the platen: 50 rpm

[0270] Rotation speed of the head (carrier): 52 rpm

[0271] Polishing pad: Product name "POLYPAS275NX" manufactured by Fujibo Ehime Co., Ltd.

[0272] Supply rate of the polishing liquid: 1.5 L / minute

[0273] Temperature of the polishing liquid: 20 °C

[0274] Temperature of the platen cooling water: 20 °C

[0275] Polishing time: 4 minutes

[0276] Remove the polished silicon wafer from the polishing apparatus and clean it (SC-1 cleaning) using a cleaning solution of NH4OH (29%):H2O2 (31%):deionized water (DIW) = 1:1:12 (volume ratio). Specifically, prepare two cleaning tanks, the first and the second, and store the above cleaning solution in these tanks and maintain it at 70 °C. Immerse the polished silicon wafer in the first cleaning tank for 10 minutes, then, after passing through a rinsing tank filled with ultrapure water and applying ultrasonic waves, immerse it in the second cleaning tank for 10 minutes, and then, after passing through a rinsing tank filled with ultrapure water and applying ultrasonic waves, dry it using a spin dryer.

[0277] <Measurement of LPD-N number>

[0278] For the surface of the cleaned silicon wafer, using a wafer inspection device manufactured by KLA TENCOR Corporation, trade name "Surfscan SP5", the number of LPD-N greater than 36 nm was measured in the DCO mode. The obtained results were converted into relative values with the LPD-N number of Comparative Example 3 as 100%, and the obtained values were recorded in the corresponding columns of Table 2.

[0279] <Measurement of LPD number>

[0280] For the surface of the cleaned silicon wafer, using a wafer inspection device manufactured by KLA TENCOR Corporation, trade name "Surfscan SP5", the number of LPD greater than 19 nm was measured in the DCO mode. The obtained results were converted into relative values with the LPD number of Comparative Example 3 as 100%, and the obtained values were recorded in the corresponding columns of Table 2.

[0281] <Haze measurement>

[0282] For the surface of the cleaned silicon wafer, using a wafer inspection device manufactured by KLA TENCOR Corporation, trade name "Surfscan SP5", the haze (ppm) was measured in the DW2O mode. The obtained results were converted into relative values with the haze value of Comparative Example 3 as 100%, and the obtained values were recorded in the corresponding columns of Table 2.

[0283] [Table 2]

[0284] Table 2

[0285] LPD-N number [%] LPD number [%] Haze [%] Embodiment 14 45 99 99 Comparative Example 3 100 100 100

[0286] As shown in Table 2, it can be determined that: compared with the polishing composition of Comparative Example 3 prepared using the substrate protectant described in Comparative Example 1 of Test Example 1, the number of LPD-N in the polishing composition of Example 14 prepared using the substrate protectant described in Example 3 of Test Example 1 was significantly reduced.

[0287] The specific examples of the present invention have been described in detail above, but they are merely illustrative and do not limit the claims. The technologies described in the claims include technologies obtained by various deformations and changes of the above-described specific examples.< / ph>

Claims

1. A method for producing a polishing composition, wherein: The polishing composition comprises abrasive grains, a basic compound, a cellulose derivative and a surfactant. The manufacturing method comprises: step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, The manufacturing method also includes the following steps: A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

2. The method for producing a polishing composition according to claim 1, wherein: In the step (B2) or the step (C1), the raw material surfactant is added in a state heated to a temperature higher than room temperature.

3. A method for producing a substrate protective agent, wherein: The substrate protecting agent comprises a cellulose derivative and a surfactant, The manufacturing method comprises: step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, The manufacturing method also includes the following steps: A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

4. A substrate protective agent comprising a cellulose derivative and a surfactant, wherein the substrate protective agent is prepared by the following method: The method comprises: step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, The method also includes the following steps: A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution.

5. A polishing composition comprising abrasive grains, a basic compound and a substrate protective agent, The substrate protecting agent comprises a cellulose derivative and a surfactant, Here, the substrate protective agent is prepared by the following method: The method comprises: step (A) of dissolving a raw material cellulose derivative in a solvent to prepare a raw material cellulose derivative solution, The method also includes the following steps: A step (B1) of heating the raw material cellulose derivative solution, and a step (B2) of adding a raw material surfactant to the raw material cellulose derivative solution after the step (B1); or, A step (C1) of adding a raw material surfactant to the raw material cellulose derivative solution to prepare an additive mixed solution, and a step (C2) of heating the additive mixed solution. The polishing composition according to claim 5 , which is used for polishing a surface formed of a silicon material. 7 . A concentrated solution, which is a concentrated solution of the polishing composition according to claim 5 or 6 .

8. A grinding method, comprising: A step of polishing a surface of a silicon material using the polishing composition according to claim 5 or 6.

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