Slurry and polishing method

Abstract

The present invention provides a slurry containing abrasive grains and water, wherein the abrasive grains contain cerium oxide particles, and in a peak P of maximum intensity existing in the range of a diffraction angle 2θ from 27.000 to 29.980 deg in an X-ray diffraction pattern of the cerium oxide particles, a peak line width Wa at an intensity that is 10% of the maximum intensity and a peak line width Wb at an intensity that is 50% of the maximum intensity have a ratio Wa / Wb between 2.50 and 3.30.

Description

Slurry and polishing method

[0001] The present disclosure relates to slurries, polishing methods, and the like.

[0002] In recent years, processing techniques for achieving higher density and finer features have become increasingly important in the manufacturing process of semiconductor devices. One such processing technique, chemical mechanical polishing (CMP), has become essential for forming shallow trench isolation (hereinafter referred to as "STI"), planarizing pre-metal insulating materials or interlayer insulating materials, forming plugs or buried metal wiring, and the like in the manufacturing process of semiconductor devices.

[0003] The most commonly used polishing liquids include, for example, silica-based polishing liquids containing silica (silicon oxide) particles such as fumed silica and colloidal silica as abrasive grains. Silica-based polishing liquids are characterized by their high versatility, and by appropriately selecting the abrasive grain content, pH, additives, etc., they can polish a wide variety of materials, regardless of whether they are insulating or conductive.

[0004] On the other hand, there is an increasing demand for cerium oxide-based polishing solutions containing cerium oxide particles as abrasive grains. For example, cerium oxide-based polishing solutions can polish insulating materials at high speeds even with a lower abrasive grain content than silica-based polishing solutions (see, for example, Patent Documents 1 and 2 listed below).

[0005] JP-A-10-106994 JP-A-08-022970

[0006] Recently, 3D-NAND devices, in which device cells are stacked vertically, have become popular. In this technology, the step height of the insulating material during cell formation is several times higher than that of conventional planar devices. Therefore, to maintain the throughput of device manufacturing, it is necessary to quickly eliminate the high step height in a CMP process or the like, which requires an improvement in the polishing speed of the insulating material.

[0007] An object of one aspect of the present disclosure is to provide a slurry capable of achieving a high removal rate of insulating materials.An object of another aspect of the present disclosure is to provide a polishing method using such a slurry.

[0008] In some aspects, the present disclosure relates to the following [1] to [7], etc. [1] A slurry containing abrasive grains and water, wherein the abrasive grains include cerium oxide particles, and wherein, in an X-ray diffraction pattern of the cerium oxide particles, the ratio Wa / Wb of the peak line width Wa at 10% of the maximum intensity to the peak line width Wb at 50% of the maximum intensity in a diffraction angle 2θ range of 27.000 to 29.980 deg is 2.50 to 3.30. [2] The slurry according to [1], wherein the ratio Wa / Wb is 2.70 to 3.20. [3] The slurry according to [1] or [2], wherein the abrasive grains have an average particle size of 200 to 400 nm. [4] The slurry according to any one of [1] to [3], wherein the abrasive grains are contained in an amount of 0.01 to 10.00 mass%. [5] The slurry according to any one of [1] to [4], which has a pH of 1.00 to 7.00. [6] The slurry according to any one of [1] to [5], which is used for polishing a surface to be polished that contains silicon oxide. [7] A polishing method comprising a step of polishing a surface to be polished using the slurry according to any one of [1] to [6].

[0009] According to one aspect of the present disclosure, there is provided a slurry capable of achieving a high removal rate of insulating materials. According to another aspect of the present disclosure, there is provided a polishing method using such a slurry.

[0010] FIG. 2 is a diagram for explaining how to determine peak line widths Wa and Wb in the X-ray diffraction pattern of cerium oxide particles.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail.

[0012] <Definitions> In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range less than A and A. In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper or lower limit of a numerical range in another stage. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. The term "film" encompasses not only a structure having a shape formed over the entire surface when observed in a plan view, but also a structure having a shape formed on a portion of the surface. The term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0013] As will be described later, the slurry according to this embodiment contains abrasive grains. Abrasive grains are also called "abrasive particles," but are referred to as "abrasive grains" in this specification. Abrasive grains are generally solid particles, and during polishing, the material to be removed is thought to be removed by the mechanical action of the abrasive grains and the chemical action of the abrasive grains (mainly the surfaces of the abrasive grains), but this is not limiting.

[0014] <Slurry> The slurry according to this embodiment contains abrasive grains and water. The slurry according to this embodiment can be used, for example, as a polishing liquid (CMP polishing liquid). In this specification, the term "polishing liquid" is defined as a composition that comes into contact with the surface to be polished during polishing. The term "polishing liquid" itself does not limit the components contained in the polishing liquid.

[0015] In the slurry according to this embodiment, the abrasive grains contain cerium oxide particles, and in the X-ray diffraction pattern of the cerium oxide particles, a peak P of maximum intensity exists in the range of a diffraction angle 2θ of 27.000 to 29.980 deg. The ratio Wa / Wb (hereinafter referred to as "parameter X"; X = Wa / Wb) of the peak line width Wa at 10% of the maximum intensity to the peak line width Wb at 50% of the maximum intensity is 2.50 to 3.30.

[0016] The slurry according to this embodiment can achieve a high polishing rate for insulating materials, for example, a high polishing rate for silicon oxide. The slurry according to this embodiment can achieve a polishing rate of, for example, 1700 nm / min or more (preferably, 1750 nm / min or more, 1800 nm / min or more, 1900 nm / min or more, 2000 nm / min or more, etc.) after 20 seconds of polishing, as evaluated by the methods described in the Examples below.

[0017] When using a slurry as a cerium oxide-based polishing liquid to quickly eliminate high step differences in an insulating material (e.g., silicon oxide), a problem arises in that the polishing rate decreases as polishing progresses, resulting in a longer time required to eliminate the step differences. Therefore, a slurry for eliminating high step differences is required to have both a high initial polishing rate and the ability to maintain the polishing rate. According to one aspect of the slurry of this embodiment, it is possible to obtain a high polishing rate for insulating materials while suppressing a decrease in the polishing rate as polishing progresses. For example, it is possible to obtain a high polishing rate for silicon oxide while suppressing a decrease in the polishing rate as polishing progresses. According to one aspect of the slurry of this embodiment, in the evaluation method described in the Examples below, the polishing rate maintenance rate (polishing rate after 50 seconds of polishing / polishing rate after 20 seconds of polishing) can be, for example, more than 75.0% (preferably, 75.3% or more, 80.0% or more, 85.0% or more, 88.0% or more, 90.0% or more, 95.0% or more, 98.0% or more, etc.).

[0018] The factors that enable a high polishing rate for insulating materials to be obtained while suppressing a decrease in the polishing rate as polishing progresses are not necessarily clear, but are presumed to be as follows. However, the factors are not limited to the following. That is, according to the findings of the present inventors, adjusting the shape of the peak P of maximum intensity present in a specific diffraction angle range in the X-ray diffraction pattern of cerium oxide particles is effective for adjusting the polishing rate for insulating materials and the maintainability of the polishing rate, and adjusting the parameter X, which represents the broadening of the base of peak P, can satisfactorily achieve both the polishing rate for insulating materials and the maintainability of the polishing rate. It is presumed that parameter X depends on the state of the fine crystallite components in the cerium oxide particles. Particles containing a large amount of fine crystallite components and having many grain boundaries are likely to crack at the grain boundaries as polishing progresses, exposing new highly reactive crystal planes (high chemical reactivity), but physical polishing performance may decrease as the particles become smaller. On the other hand, when the parameter X satisfies the above-mentioned specific range, it is presumed that the state of the fine crystallite components is favorable, thereby enhancing the chemical reactivity of the abrasive grains without reducing the physical polishing performance, and achieving a good balance between the polishing rate for the insulating material and the maintainability of the polishing rate.

[0019] According to one aspect of the slurry of this embodiment, in the evaluation method described in the Examples below, a polishing rate of, for example, 1300 nm / min or more (preferably, 1400 nm / min or more, 1500 nm / min or more, 1600 nm / min or more, 1700 nm / min or more, etc.) can be obtained after 50 seconds of polishing.

[0020] According to this embodiment, it is possible to provide a method for adjusting a polishing rate by adjusting a polishing rate based on parameter X, and a method for adjusting a polishing rate maintenance rate by adjusting a polishing rate maintenance rate based on parameter X. According to this embodiment, it is possible to provide a method for selecting abrasive grains by selecting abrasive grains containing cerium oxide particles based on parameter X. According to this embodiment, it is possible to provide use of a slurry for polishing a polished surface containing an insulating material, and it is possible to provide use of a slurry for polishing a polished surface containing silicon oxide. According to this embodiment, it is possible to provide use of a slurry for a substrate surface planarization process, which is a semiconductor device manufacturing technology. According to this embodiment, it is possible to provide use of a slurry for a planarization process of an STI insulating material, a pre-metal insulating material, or an interlayer insulating material.

[0021] (Abrasive Grains) The slurry according to this embodiment contains abrasive grains, and the abrasive grains include cerium oxide particles (particles containing cerium oxide). The cerium oxide of the cerium oxide particles may contain tetravalent cerium or may contain trivalent cerium.

[0022] The abrasive grains may contain particles other than cerium oxide particles, such as silicon oxide (silica) particles, aluminum oxide (alumina) particles, silicon nitride particles, zirconium oxide (zirconia: yttria-doped zirconia particles, etc.) particles, titanium oxide (titania) particles, yttrium oxide (yttria) particles, silicon carbide particles, diamond particles, and polymer particles.

[0023] The content of cerium oxide (cerium oxide particles) may be in the following ranges based on the total mass of the abrasive grains (total mass of the abrasive grains contained in the slurry). From the viewpoint of easily achieving a high removal rate of the insulating material, the content of cerium oxide (cerium oxide particles) may be 20 mass% or more, 30 mass% or more, 40 mass% or more, 50 mass% or more, more than 50 mass%, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more. The abrasive grains contained in the slurry may be essentially composed of cerium oxide (cerium oxide particles) (the content of cerium oxide (cerium oxide particles) is essentially 100 mass% based on the total mass of the abrasive grains contained in the slurry).

[0024] Cerium oxide particles can be obtained, for example, by oxidizing a cerium compound. Methods for oxidizing the cerium compound include a calcination method and an oxidation method using hydrogen peroxide, etc., and the calcination method is preferred from the viewpoint of easily achieving a high polishing rate for insulating materials and easily preventing a decrease in the polishing rate as polishing progresses. Examples of cerium compounds include cerium carbonate, cerium nitrate, cerium sulfate, and cerium oxalate. From the viewpoint of easily achieving a high polishing rate for insulating materials and easily preventing a decrease in the polishing rate as polishing progresses, the cerium compound may be cerium carbonate, and the cerium oxide particles may contain an oxide derived from cerium carbonate.

[0025] Cerium carbonate for producing cerium oxide particles can be obtained, for example, by the following procedure using natural minerals as raw materials. First, rare earth concentrates (e.g., bastnaesite concentrate, monazite concentrate, Chinese complex concentrate) are obtained by removing unwanted gangue from ores containing rare earth elements, including at least cerium, such as bastnaesite ore, heavy sand, and iron dolomite, through ore dressing. Next, the rare earth concentrate is subjected to chemical treatments (e.g., alkali decomposition, sulfuric acid decomposition, hydroxide fractional precipitation) to reduce insoluble components such as impurities, and then, if necessary, rare earth elements (e.g., neodymium) are reduced by solvent extraction to obtain a cerium-containing rare earth salt solution. Finally, cerium carbonate is obtained by mixing this cerium-containing rare earth salt solution with sodium carbonate. For convenience, this method of producing cerium carbonate is defined as the "extraction method."

[0026] By replacing the sodium carbonate used in the "extraction method" with another salt, other cerium salts (such as cerium nitrate, cerium sulfate, and cerium oxalate) can be synthesized. For example, cerium nitrate (e.g., cerium(III) nitrate) can be obtained by mixing a cerium-containing rare earth salt solution with sodium nitrate. Cerium carbonate can be obtained by reacting an aqueous solution of a cerium salt with a solution of a precursor having a carbonyl group. For example, cerium carbonate can be precipitated by reacting an aqueous solution of cerium nitrate (e.g., cerium(III) nitrate) with a solution of a precursor having a carbonyl group at a temperature of 80 to 100°C. Urea, for example, can be used as the precursor having a carbonyl group. This method of producing cerium carbonate is conveniently defined as the "carbonyl substitution method." The method of producing cerium carbonate in this embodiment may be either the "extraction method" or the "carbonyl substitution method," or may be the "carbonyl substitution method," from the viewpoints of easily achieving a high polishing rate for insulating materials and easily suppressing a decrease in the polishing rate as polishing progresses.

[0027] In the slurry according to this embodiment, in the X-ray diffraction pattern (XRD chart) of the cerium oxide particles, the maximum intensity peak (hereinafter referred to as "peak P") exists in the diffraction angle 2θ range of 27.000 to 29.980 degrees. The ratio Wa / Wb (parameter X=Wa / Wb) of the peak line width Wa at 10% of the maximum intensity to the peak line width Wb at 50% of the maximum intensity is 2.50 to 3.30. Parameter X can be used as an index representing the broadening of the base of the main peak P appearing in the 2θ range of 27.000 to 29.980 degrees in the X-ray diffraction pattern of the cerium oxide particles. In this embodiment, the base of peak P has a specific broadening pattern. By using the peak line width at 10% of the maximum intensity instead of the peak line width at zero intensity (no count), it is easy to evaluate the broadening of the base of peak P while avoiding the influence of background. The peak line width may be referred to as peak width, diffraction line width, etc. The diffraction angle 2θ giving the maximum intensity of peak P is located in the range of 27.000 to 29.980 deg.

[0028] When the maximum intensity (highest count, peak top) of peak P is 100% and the intensity of zero (no count) in the X-ray diffraction pattern is 0%, as shown in FIG. 1, the peak line width Wa is the peak line width [deg] at an intensity (count) corresponding to 10% of the maximum intensity, and the peak line width Wb is the peak line width [deg] at an intensity (count) corresponding to 50% of the maximum intensity. When measuring the peak line widths Wa and Wb from the X-ray diffraction pattern, if the background is large relative to peak P, the background may be removed using a general background removal method (such as the Sonneveld-Visser method). The X-ray diffraction pattern for calculating the parameter X can be obtained using a general powder X-ray diffractometer, and can be obtained, for example, as XRD using CuKα radiation, by the method described in the examples below.

[0029] It is presumed that the parameter X of 2.50 or more improves the chemical reactivity of the cerium oxide particles, thereby improving the polishing rate for insulating materials, and that the parameter X of 3.30 or less improves the physical strength of the cerium oxide particles, thereby improving the polishing rate for insulating materials and the maintainability of the polishing rate.

[0030] From the viewpoints of easily improving the chemical reactivity of the cerium oxide particles and easily improving the removal rate for insulating materials and the maintenance of the removal rate, the parameter X may be 2.55 or more, 2.60 or more, 2.63 or more, 2.64 or more, 2.65 or more, 2.70 or more, more than 2.70, 2.71 or more, 2.72 or more, or 2.73 or more. From the viewpoints of easily improving the removal rate for insulating materials and the maintenance of the removal rate, the parameter X may be 2.75 or more, 2.80 or more, 2.85 or more, 2.90 or more, 2.95 or more, or 2.97 or more. From the viewpoints of easily improving the physical strength of the cerium oxide particles and easily improving the removal rate for insulating materials and the maintenance of the removal rate, the parameter X may be 3.20 or less, less than 3.20, 3.15 or less, 3.10 or less, less than 3.10, 3.05 or less, 3.00 or less, less than 3.00, or 2.98 or less. From the viewpoint of easily improving the maintainability of the polishing rate, the parameter X may be 2.97 or less, 2.95 or less, 2.90 or less, 2.85 or less, 2.80 or less, 2.75 or less, or 2.73 or less. The parameter X may be 2.72 or less, 2.71 or less, 2.70 or less, 2.65 or less, 2.64 or less, or 2.63 or less. From these viewpoints, the parameter X may be 2.60 to 3.30, 2.70 to 3.30, 2.80 to 3.30, 2.90 to 3.30, 2.50 to 3.20, 2.60 to 3.20, 2.70 to 3.20, 2.80 to 3.20, 2.90 to 3.20, 2.50 to 3.00, 2.60 to 3.00, 2.70 to 3.30, 0.00, 2.80 to 3.00, 2.90 to 3.00, 2.50 to 2.97, 2.60 to 2.97, 2.70 to 2.97, 2.80 to 2.97, 2.90 to 2.97, 2.50 to 2.80, 2.60 to 2.80, 2.70 to 2.80, 2.50 to 2.70, or 2.60 to 2.70.

[0031] Methods for adjusting the parameter X include changing the composition of the raw materials, changing the method for preparing the raw materials, changing the firing temperature, firing time, etc. in the firing method, and changing the grinding method, conditions, etc. These methods may be used alone or in combination.

[0032] The cerium oxide particles to be measured by XRD to obtain the parameter X may be recovered by drying the slurry (to dryness), or by separating and removing components other than the cerium oxide particles from the dried product. When the parameter X of the cerium oxide particles does not change during the preparation of the slurry, the cerium oxide particles to be measured by XRD may be the cerium oxide particles before being mixed with other components such as water.

[0033] The peak line width Wb at an intensity that is 50% of the maximum intensity may be in the following range, from the viewpoint of obtaining a high removal rate for the insulating material while easily suppressing a decrease in the removal rate as the polishing progresses: The peak line width Wb may be 0.23 deg or more, 0.24 deg or more, 0.25 deg or more, 0.26 deg or more, 0.30 deg or more, 0.31 deg or more, 0.33 deg or more, 0.34 deg or more, 0.35 deg or more, 0.36 deg or more, more than 0.36 deg, 0.40 deg or more, 0.44 deg or more, 0.45 deg or more, 0.50 deg or more, 0.55 deg or more, or 0.60 deg or more. The peak line width Wb may be 0.62 deg or less, 0.60 deg or less, 0.55 deg or less, 0.50 deg or less, 0.45 deg or less, 0.44 deg or less, 0.40 deg or less, 0.36 deg or less, 0.35 deg or less, 0.34 deg or less, 0.33 deg or less, 0.31 deg or less, 0.30 deg or less, 0.26 deg or less, less than 0.26 deg, 0.25 deg or less, or 0.24 deg or less. From these viewpoints, the peak line width Wb may be 0.23 to 0.62 deg, 0.23 to 0.45 deg, 0.23 to 0.40 deg, 0.23 to 0.33 deg, 0.25 to 0.62 deg, 0.25 to 0.45 deg, 0.25 to 0.40 deg, 0.25 to 0.33 deg, 0.33 to 0.62 deg, 0.33 to 0.45 deg, 0.33 to 0.40 deg, 0.40 to 0.62 deg, 0.40 to 0.45 deg, or 0.45 to 0.62 deg.

[0034] The average particle size of the abrasive grains or the average particle size of the cerium oxide particles may be in the following ranges: from the viewpoint of easily achieving a high removal rate for the insulating material, the average particle size may be 100 nm or more, 150 nm or more, 175 nm or more, more than 175 nm, 180 nm or more, 200 nm or more, 220 nm or more, 230 nm or more, 240 nm or more, 245 nm or more, 250 nm or more, 255 nm or more, 260 nm or more, 265 nm or more, 270 nm or more, 275 nm or more, or 280 nm or more. From the viewpoint of easily reducing scratches caused by polishing, the average particle size may be 600 nm or less, 550 nm or less, less than 550 nm, 500 nm or less, 450 nm or less, 400 nm or less, 350 nm or less, 320 nm or less, 300 nm or less, 295 nm or less, 290 nm or less, 285 nm or less, 280 nm or less, 275 nm or less, 270 nm or less, 265 nm or less, 260 nm or less, 255 nm or less, or 250 nm or less. From these viewpoints, the average particle size may be 100 to 600 nm, 100 to 500 nm, 100 to 400 nm, 100 to 300 nm, 100 to 280 nm, 200 to 600 nm, 200 to 500 nm, 200 to 400 nm, 200 to 300 nm, 200 to 280 nm, 250 to 600 nm, 250 to 500 nm, 250 to 400 nm, 250 to 300 nm, 250 to 280 nm, 270 to 600 nm, 270 to 500 nm, 270 to 400 nm, 270 to 300 nm, or 270 to 280 nm.

[0035] The average particle size refers to the MV (volume mean diameter) value measured using a laser diffraction particle size distribution analyzer, and can be measured, for example, by the method described in the Examples below. The average particle size (volume mean diameter) can be measured by adjusting the abrasive grain content or cerium oxide particle content to an appropriate content by diluting the slurry with water. For example, in the case of "SYNC" (product name) manufactured by Microtrac-Bell Corporation, the content can be adjusted to a DV (Diffraction Volume) value of 0.0010 to 0.0150. The DV value is a concentration index utilizing the total amount of scattered light from a sample received by a detector, and tends to increase as the abrasive grain content or cerium oxide particle content in the sample increases. When a slurry containing abrasive grains (abrasive grains including cerium oxide particles), additives, and water is stored separately in a first liquid containing abrasive grains and water and a second liquid containing additives and water, the first liquid can be diluted with water to adjust the abrasive grain content to an appropriate content, and the average particle size can be measured.

[0036] Methods for adjusting the average particle size include adjusting the raw material composition, production method, firing temperature, firing time, etc., pulverization, classification, filtration, etc. The pulverization, classification, and filtration may be performed on the abrasive grains or cerium oxide particles, or on the raw material (a cerium compound such as cerium carbonate) for obtaining the cerium oxide particles.

[0037] The content of the abrasive grains in the slurry may be in the following ranges based on the total mass of the slurry: From the viewpoint of easily achieving a high removal rate of the insulating material, the content of the abrasive grains may be 0.01 mass % or more, 0.05 mass % or more, 0.10 mass % or more, 0.15 mass % or more, 0.30 mass % or more, 0.50 mass % or more, 0.80 mass % or more, 1.00 mass % or more, 1.20 mass % or more, 1.50 mass % or more, 1.80 mass % or more, or 2.00 mass % or more. The content of abrasive grains may be 20.00% by mass or less, 15.00% by mass or less, 10.00% by mass or less, 8.00% by mass or less, 5.00% by mass or less, 4.50% by mass or less, 4.00% by mass or less, 3.50% by mass or less, 3.00% by mass or less, 2.50% by mass or less, or 2.00% by mass or less, from the viewpoint of suppressing particle aggregation and making it less likely to scratch the polished surface. From these viewpoints, the content of the abrasive grains may be 0.01 to 20.00 mass%, 0.01 to 10.00 mass%, 0.01 to 5.00 mass%, 0.10 to 20.00 mass%, 0.10 to 10.00 mass%, 0.10 to 5.00 mass%, 0.50 to 20.00 mass%, 0.50 to 10.00 mass%, 0.50 to 5.00 mass%, 1.00 to 20.00 mass%, 1.00 to 10.00 mass%, or 1.00 to 5.00 mass%.

[0038] (Water) The water is not particularly limited, but examples thereof include deionized water, ultrapure water, etc. The content of water may be the remainder of the slurry excluding the contents of other constituents, and is not particularly limited.

[0039] The water content in the slurry may be within the following ranges, based on the total mass of the slurry, from the viewpoint of obtaining a high removal rate for the insulating material while easily suppressing a decrease in the removal rate as the polishing progresses. The water content may be 50 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 93 mass% or more, 95 mass% or more, 96 mass% or more, or 97 mass% or more. The water content may be less than 100 mass%, 99 mass% or less, or 98 mass% or less. From these viewpoints, the water content may be 50 mass% or more and less than 100 mass%, 50 to 99 mass%, 50 to 98 mass%, 80 mass% or more and less than 100 mass%, 80 to 99 mass%, 80 to 98 mass%, 90 mass% or more and less than 100 mass%, 90 to 99 mass%, or 90 to 98 mass%.

[0040] (Additives) The slurry according to this embodiment may contain any additive, or may not contain any additive. Examples of the optional additive include a polar solvent (ethanol, acetone, etc.), a material having a carboxyl group (excluding compounds corresponding to polyoxyalkylene compounds or water-soluble polymers), a polyoxyalkylene compound, a water-soluble polymer, an oxidizing agent (e.g., hydrogen peroxide), and a dispersant (e.g., a phosphate-based inorganic salt).

[0041] Examples of materials having a carboxyl group include monocarboxylic acids such as acetic acid, propionic acid, butyric acid, and valeric acid; hydroxy acids such as lactic acid, malic acid, and citric acid; dicarboxylic acids such as malonic acid, succinic acid, fumaric acid, and maleic acid; and amino acids such as arginine, histidine, and lysine.

[0042] Examples of the polyoxyalkylene compound include polyalkylene glycols and polyoxyalkylene derivatives.

[0043] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutylene glycol.

[0044] The polyoxyalkylene derivative is, for example, a compound in which a functional group or a substituent is introduced into a polyalkylene glycol, or a compound in which a polyalkylene oxide is added to an organic compound. Examples of the functional group or substituent include an alkyl ether group, an alkylphenyl ether group, a phenyl ether group, a styrenated phenyl ether group, a glyceryl ether group, an alkylamine group, a fatty acid ester group, and a glycol ester group. Examples of the polyoxyalkylene derivatives include polyoxyethylene alkyl ethers, polyoxyethylene bisphenol ethers (e.g., BA glycol series manufactured by Nippon Nyukazai Co., Ltd.), polyoxyethylene styrenated phenyl ethers (e.g., Emulgen series manufactured by Kao Corporation), polyoxyethylene alkylphenyl ethers (e.g., Noigen EA series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), polyoxyalkylene polyglyceryl ethers (e.g., SC-E series and SC-P series manufactured by Sakamoto Pharmaceutical Co., Ltd.), polyoxyethylene sorbitan fatty acid esters (e.g., Sorgen TW series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), polyoxyethylene fatty acid esters (e.g., Emanone series manufactured by Kao Corporation), polyoxyethylene alkylamines (e.g., Amiradin D manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and other compounds to which polyalkylene oxides are added (e.g., Surfynol 465 manufactured by Nissin Chemical Industry Co., Ltd.; TMP series manufactured by Nippon Nyukazai Co., Ltd.).

[0045] The water-soluble polymer has the effect of adjusting the dispersion stability of the abrasive grains. A "water-soluble polymer" is defined as a polymer that dissolves in an amount of 0.1 g or more in 100 g of water. Polymers that fall under the category of polyoxyalkylene compounds are not included in the "water-soluble polymer."

[0046] Examples of water-soluble polymers include polycarboxylic acids such as polyacrylic acid and polymaleic acid; acrylic polymers such as polyacrylamide and polydimethylacrylamide; polysaccharides such as carboxymethyl cellulose, agar, curdlan, dextrin, cyclodextrin, and pullulan; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrolein; and glycerin polymers such as polyglycerin and polyglycerin derivatives.

[0047] From the viewpoint of easily obtaining the effect of adding the water-soluble polymer while suppressing settling of the abrasive grains, the content of the water-soluble polymer may be in the following range based on the total mass of the slurry: The content of the water-soluble polymer may be 0.001 mass% or more, 0.005 mass% or more, 0.010 mass% or more, 0.020 mass% or more, 0.030 mass% or more, 0.040 mass% or more, 0.050 mass% or more, 0.060 mass% or more, 0.070 mass% or more, or 0.075 mass% or more. The content of the water-soluble polymer may be 10.000 mass% or less, 8.000 mass% or less, 6.000 mass% or less, 5.000 mass% or less, 3.000 mass% or less, 1.000 mass% or less, 0.500 mass% or less, 0.300 mass% or less, 0.100 mass% or less, 0.080 mass% or less, or 0.075 mass% or less. From these viewpoints, the content of the water-soluble polymer may be 0.001 to 10.000 mass%, 0.001 to 1.000 mass%, 0.001 to 0.500 mass%, 0.001 to 0.100 mass%, 0.010 to 10.000 mass%, 0.010 to 1.000 mass%, 0.010 to 0.500 mass%, 0.010 to 0.100 mass%, 0.030 to 10.000 mass%, 0.030 to 1.000 mass%, 0.030 to 0.500 mass%, 0.030 to 0.100 mass%, 0.050 to 10.000 mass%, 0.050 to 1.000 mass%, 0.050 to 0.500 mass%, or 0.050 to 0.100 mass%.

[0048] (pH) The pH of the slurry according to this embodiment may be in the following ranges: From the viewpoint of easily obtaining a high removal rate for the insulating material, the pH may be 1.00 or more, 1.50 or more, 2.00 or more, 2.50 or more, 3.00 or more, more than 3.00, 3.50 or more, more than 3.50, 4.00 or more, more than 4.00, 4.10 or more, 4.20 or more, 4.30 or more, 4.40 or more, 4.50 or more, more than 4.50, 4.60 or more, 4.70 or more, or 4.80 or more. From the viewpoint of easily improving the storage stability of the slurry, the pH may be 7.00 or less, less than 7.00, 6.50 or less, less than 6.50, 6.00 or less, less than 6.00, 5.50 or less, less than 5.50, 5.00 or less, less than 5.00, 4.90 or less, 4.85 or less, 4.80 or less, 4.75 or less, 4.70 or less, 4.65 or less, 4.60 or less, 4.55 or less, 4.50 or less, less than 4.50, 4.45 or less, 4.40 or less, 4.35 or less, 4.30 or less, 4.25 or less, or 4.20 or less. From these viewpoints, the pH may be 1.00 to 7.00, 1.00 to 6.00, 1.00 to 5.00, 1.00 to 4.50, 2.00 to 7.00, 2.00 to 6.00, 2.00 to 5.00, 2.00 to 4.50, 3.00 to 7.00, 3.00 to 6.00, 3.00 to 5.00, 3.00 to 4.50, 4.00 to 7.00, 4.00 to 6.00, 4.00 to 5.00, or 4.00 to 4.50. The pH of the slurry is defined as the pH at a liquid temperature of 25°C.

[0049] The pH of the slurry can be adjusted by adding an acid component such as an inorganic acid or an organic acid, or an alkaline component such as ammonia, sodium hydroxide, tetramethylammonium hydroxide (TMAH), imidazole, or alkanolamine. To stabilize the pH, a buffering agent or a buffer solution (a solution containing a buffering agent) may be added. Examples of the buffering agent include an acetate buffer and a phthalate buffer.

[0050] The pH of the slurry according to this embodiment can be measured with a pH meter (for example, Model PHL-40 manufactured by DKK-TOA Corporation). For example, after two-point calibration of the pH meter using a phthalate pH buffer solution (pH: 4.01) and a neutral phosphate pH buffer solution (pH: 6.86) as standard buffer solutions, the electrodes of the pH meter are placed in the slurry, and the value after stabilization for at least two minutes can be measured as the pH of the slurry. The liquid temperatures of both the standard buffer solution and the slurry are 25°C.

[0051] (Storage Mode) When the slurry according to this embodiment contains the optional additives described above, the slurry according to this embodiment may be stored in a single-liquid state containing abrasive grains, additives, and water, or may be stored as a multi-liquid (e.g., two-liquid) set in which the components of the slurry are separated into a first liquid and a second liquid, such that a first liquid containing abrasive grains and water and a second liquid containing additives and water are mixed to form a slurry. The slurry according to this embodiment may be in a single-liquid state containing abrasive grains, additives, and water, or may be the first liquid in a multi-liquid set. The second liquid may contain at least one additive, and the first liquid may contain an additive of the same or a different type as the additive in the second liquid. The components of the slurry may be stored in three or more liquids.

[0052] In the above-mentioned multiple-liquid set, the first liquid and the second liquid are mixed immediately before or during polishing to prepare a slurry. The single-liquid slurry may be stored as a stock liquid with a reduced water content and diluted with water before use during polishing. In the multiple-liquid set, the first liquid and the second liquid may be stored as stock liquids with a reduced water content and diluted with water before use during polishing.

[0053] <Polishing Method> The polishing method (e.g., a method for polishing a substrate) according to this embodiment includes a polishing step of polishing a surface to be polished (e.g., a surface to be polished of a substrate) using the slurry according to this embodiment. The slurry used in the polishing step may be a slurry obtained by mixing the first liquid and the second liquid in the multiple-liquid set described above.

[0054] In the polishing step, for example, the insulating material of a substrate having the insulating material is pressed against a polishing pad (abrasive cloth) on a polishing table, the slurry according to this embodiment is supplied between the material to be polished and the polishing pad, and the substrate and the polishing table are moved relative to each other to polish the surface to be polished of the insulating material. In the polishing step, for example, at least a portion of the insulating material is removed by polishing.

[0055] Examples of the substrate to be polished include a substrate to be polished. Examples of the substrate to be polished include a substrate in which an insulating material is formed on a substrate used in semiconductor device manufacturing (e.g., a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc. are formed). Examples of the insulating material include silicon oxide. The insulating material may be a single material or multiple materials. When multiple materials are exposed on the surface to be polished, they can be considered as insulating materials. The insulating material may be in the form of a film (insulating film) or may be a silicon oxide film.

[0056] The slurry according to this embodiment can be used to polish an insulating material (e.g., silicon oxide) formed on a substrate to remove excess portions, thereby eliminating unevenness on the surface of the insulating material and obtaining a smooth surface across the entire surface of the insulating material.

[0057] In the polishing method according to this embodiment, a general polishing apparatus having a holder capable of holding a substrate having a surface to be polished and a polishing platen to which a polishing pad can be attached can be used. Each of the holder and the polishing platen may be equipped with a motor or the like capable of changing the rotation speed.

[0058] As the polishing pad, general nonwoven fabrics, foams, non-foams, etc. can be used. As the material of the polishing pad, resins such as polyurethane, acrylic resin, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly4-methylpentene, cellulose, cellulose ester, polyamide (e.g., Nylon (trade name) and aramid), polyimide, polyimideamide, polysiloxane copolymer, oxirane compound, phenolic resin, polystyrene, polycarbonate, and epoxy resin can be used. From the viewpoint of easily obtaining an excellent polishing rate and flatness, the material of the polishing pad may be at least one selected from the group consisting of foamed polyurethane and non-foamed polyurethane. The polishing pad may be grooved to allow slurry to accumulate.

[0059] There are no restrictions on the polishing conditions, but the upper limit of the rotation speed of the polishing plate is 200 min to prevent the substrate from flying out. －１ (min －１ = rpm) or less, and the upper limit of the polishing pressure (processing load) applied to the substrate may be 100 kPa or less from the viewpoint of easily suppressing the occurrence of polishing scratches. During polishing, slurry may be continuously supplied to the polishing pad by a pump or the like. In this case, there is no limit to the amount of slurry supplied, but the surface of the polishing pad may be constantly covered with slurry.

[0060] The slurry and polishing method according to the present embodiment may be used to polish a surface containing silicon oxide. The slurry and polishing method according to the present embodiment are suitable for forming shallow trench isolation (STI) and for high-speed polishing of interlayer insulating materials. Such silicon oxide may have some of its constituent elements substituted with carbon atoms, nitrogen atoms, etc.

[0061] The slurry and polishing method according to this embodiment can also be used to polish pre-metal insulating materials, such as silicon oxide, phosphorus silicate glass, boron-phosphorus silicate glass, silicon oxyfluoride, and amorphous carbon fluoride.

[0062] The slurry and polishing method according to this embodiment can be applied to materials other than insulating materials such as silicon oxide, etc. Examples of such materials include high-dielectric-constant materials such as Hf-based, Ti-based, and Ta-based oxides; semiconductor materials such as silicon, amorphous silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, and organic semiconductors; phase-change materials such as GeSbTe; inorganic conductive materials such as ITO; and polymer resin materials such as polyimide, polybenzoxazole, acrylic, epoxy, and phenolic.

[0063] The slurry and polishing method according to this embodiment can be applied not only to film-like objects to be polished, but also to various substrates made of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, etc.

[0064] The slurry and polishing method according to this embodiment can be used not only for manufacturing semiconductor elements, but also for manufacturing image display devices such as TFTs and organic ELs; optical components such as photomasks, lenses, prisms, optical fibers and single crystal scintillators; optical elements such as optical switching elements and optical waveguides; light-emitting elements such as solid-state lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.

[0065] <Manufacturing Method, etc.> The component manufacturing method according to this embodiment includes a component fabrication step in which a component is obtained using a substrate (a member to be polished) polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the component manufacturing method according to this embodiment. The component according to this embodiment is not particularly limited, and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing method according to this embodiment, an electronic component is obtained using a substrate polished by the polishing method according to this embodiment. As one aspect of the component manufacturing method according to this embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a substrate polished by the polishing method according to this embodiment. The component manufacturing method according to this embodiment may include a polishing step in which a substrate is polished by the polishing method according to this embodiment before the component fabrication step.

[0066] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a substrate (a polished member) polished by the polishing method according to this embodiment. The singulation process may be, for example, a process for dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to this embodiment, the electronic component manufacturing method according to this embodiment may include a process for singulating a substrate polished by the polishing method according to this embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to this embodiment, the semiconductor component manufacturing method according to this embodiment may include a process for singulating a substrate polished by the polishing method according to this embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0067] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a connection process in which a substrate (a polished member) polished by the polishing method according to this embodiment is connected (e.g., electrically connected) to another connected object. The connected object to be connected to the substrate polished by the polishing method according to this embodiment is not particularly limited and may be the substrate polished by the polishing method according to this embodiment, or may be a connected object different from the substrate polished by the polishing method according to this embodiment. In the connection process, the substrate and the connected object may be directly connected (connected in a state where the substrate and the connected object are in contact with each other), or the substrate and the connected object may be connected via another member (such as a conductive member). The connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0068] The connecting step may be a step of connecting a polished surface of a base polished by the polishing method according to this embodiment to a connected body, or a step of connecting a connecting surface of a base polished by the polishing method according to this embodiment to a connecting surface of a connected body. The connecting surface of the base may be a polished surface polished by the polishing method according to this embodiment. A connecting body including a base and a connected body can be obtained by the connecting step. In the connecting step, if the connecting surface of the base has a metal portion, the connected body may be brought into contact with the metal portion. In the connecting step, if the connecting surface of the base has a metal portion and the connecting surface of the connected body has a metal portion, the metal portions may be brought into contact with each other. The metal portion may contain copper.

[0069] The device according to this embodiment (for example, an electronic device such as a semiconductor device) includes a substrate polished by the polishing method according to this embodiment and at least one selected from the group consisting of the part according to this embodiment.

[0070] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited to the following examples.

[0071] <Slurry Preparation> (Comparative Example 1) Based on the above-described "extraction method," a 0.1 mol / L aqueous solution of cerium (III) sulfate and a 0.1 mol / L aqueous solution of sodium carbonate were mixed at a volume ratio of 1:2 while maintaining the temperature at 95°C, thereby producing a cerium carbonate precipitate. This precipitate was filtered and dried to obtain cerium carbonate powder (raw material). This cerium carbonate powder was placed in an alumina container and calcined in air at a calcination temperature of 800°C for 1 hour using an oven "HPM-2N" manufactured by AS ONE Corporation, thereby obtaining a white powder. Phase identification of this powder was performed by XRD, and it was confirmed to be a cerium oxide powder.

[0072] This cerium oxide powder was crushed in a mortar and then passed through a sieve with 450 μm mesh to obtain a crushed product. This crushed product, pure water, and acetic acid were mixed in a mass ratio of 20.00:79.94:0.06 to obtain a mixture, and then this mixture was pulverized for 30 minutes using a wet pulverization device "Starburst Lab HJP-25005" manufactured by Sugino Machine Co., Ltd. (pressure 245 MPa) to obtain a dispersion. This dispersion was centrifuged for 60 seconds using a centrifuge "himac CR7" manufactured by Hitachi Koki Co., Ltd. (rotation speed 2000 rpm), and the liquid remaining in the upper part of the container after centrifugation was used to obtain a dispersion containing cerium oxide particles. The cerium oxide particles were then recovered from this dispersion.

[0073] The cerium oxide particles (abrasive grains), pure water, and polyglycerin (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name: Polyglycerin #750) were mixed in a mass ratio of 2.000:97.925:0.075 to obtain a polishing slurry.

[0074] Example 1 A polishing slurry was obtained in the same manner as in Comparative Example 1, except that the firing temperature was changed to 700°C.

[0075] Example 2 Based on the above-mentioned "carbonyl substitution method," a 0.1 mol / L aqueous solution of cerium (III) nitrate and a 7.8 mol / L aqueous solution of urea were mixed at a volume ratio of 6:1 while maintaining the temperature at 95°C, thereby producing a precipitate of cerium carbonate. The precipitate was filtered and dried to obtain cerium carbonate powder (raw material). This cerium carbonate powder was placed in an alumina container and calcined in air at a calcination temperature of 800°C for 1 hour using an oven "HPM-2N" manufactured by AS ONE Corporation, thereby obtaining a white powder. Phase identification of this powder was performed by XRD, and it was confirmed to be a cerium oxide powder.

[0076] This cerium oxide powder was crushed in a mortar and then passed through a sieve with 450 μm mesh to obtain a crushed product. This crushed product, pure water, and acetic acid were mixed in a mass ratio of 20.00:79.94:0.06 to obtain a mixture, and then this mixture was pulverized for 10 minutes using a wet pulverization device "Starburst Lab HJP-25005" manufactured by Sugino Machine Co., Ltd. (pressure 245 MPa) to obtain a dispersion. This dispersion was centrifuged for 60 seconds using a centrifuge "himac CR7" manufactured by Hitachi Koki Co., Ltd. (rotation speed 2000 rpm), and the liquid remaining in the upper part of the container after centrifugation was used to obtain a dispersion containing cerium oxide particles. The cerium oxide particles were then recovered from this dispersion.

[0077] The cerium oxide particles (abrasive grains), pure water, and polyglycerin (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name: Polyglycerin #750) were mixed in a mass ratio of 2.000:97.925:0.075 to obtain a polishing slurry.

[0078] Example 3 A polishing slurry was obtained in the same manner as in Example 2, except that the firing temperature was changed to 700°C.

[0079] Example 4 A polishing slurry was obtained in the same manner as in Example 2, except that the baking temperature was changed to 500°C.

[0080] Example 5 A polishing slurry was obtained in the same manner as in Comparative Example 1, except that the firing temperature was changed to 600°C.

[0081] Comparative Example 2 A polishing slurry was obtained in the same manner as in Comparative Example 1, except that the firing temperature was changed to 500°C.

[0082] <Average particle size> An appropriate amount of each of the slurries described above was placed in a laser diffraction particle size distribution analyzer (manufactured by Microtrac Bell Corporation, product name "SYNC", particle refractive index: 2.20), and MV (volume mean diameter) was obtained as the average particle size of the abrasive grains. The measurement results are shown in Table 1.

[0083] <Parameter X> Each of the above slurries was placed in a commercially available evaporating dish and then dried for 24 hours in a vacuum dryer (ADP200, manufactured by Yamato Scientific Co., Ltd., 40°C, approximately 1000 Pa) to obtain a dried product. This dried product was crushed in a mortar and then subjected to XRD measurement under the following conditions to obtain an X-ray diffraction pattern. The peak P with the maximum intensity present in the diffraction angle 2θ range of 27.000 to 29.980 deg in the X-ray diffraction pattern was identified, and the peak line width Wa at 10% of the maximum intensity and the peak line width Wb at 50% of the maximum intensity were obtained. Parameter X was then calculated based on "X = Wa / Wb."

[0084] [XRD measurement conditions] XRD device: sample horizontal type multipurpose X-ray diffractometer Ultima IV (manufactured by Rigaku Corporation) X-ray source: CuKα ray Scanning method: 2θ / θ X-ray tube voltage: 40 kV X-ray tube current: 40 mA Divergence slit: 1 deg Divergence vertical limiting slit: 10 mm Scattering slit: 1 deg Receiving slit: 0.15 mm Kβ filter: none (counter monochromator used) Scan range: 3 to 90 deg Step: 0.01 deg Scan speed: 0.5 deg / min

[0085] <Slurry pH> The pH (25° C.) of each of the above slurries was measured using a model PHL-40 manufactured by DKK-TOA Corp. The measurement results are shown in Table 1.

[0086] <CMP Evaluation> Using each of the above slurries, CMP evaluation was carried out under the following conditions.

[0087] [CMP Polishing Conditions] Polishing Apparatus: Reflexion LK CMP (Applied Materials) Slurry Flow Rate: 250 mL / min Polishing Substrate: A blanket wafer without a pattern was used, which had a 2 μm-thick silicon oxide film formed on the silicon substrate by plasma CVD. Polishing Pad: Closed-Cell Polyurethane Resin (Nitta DuPont, Model IK4250H) Polishing Pressure: 27.6 kPa (4 psi) Rotational Speed ​​of the Polishing Substrate and Polishing Platen: Polishing Substrate / Polishing Platen = 117 / 123 rpm Polishing Time: 20 seconds and 50 seconds Wafer Cleaning: After CMP processing, the wafer was washed with water while applying ultrasonic waves and then dried using a spin dryer.

[0088] For the silicon oxide film polished and cleaned under the above conditions, the polishing rates for 20-second polishing and 50-second polishing were calculated using the following formula. The results are shown in Table 1. The difference in film thickness of the silicon oxide film before and after polishing was calculated using an optical interference film thickness measuring device (manufactured by NOVA, product name: Nova i500). Polishing rate = difference in film thickness of silicon oxide film before and after polishing [nm] / polishing time [min]

[0089] Using the polishing rates for the 20-second polishing and the 50-second polishing, the polishing rate retention rate was calculated according to the following formula. The results are shown in Table 1. Polishing rate retention rate [%] = (polishing rate for 50-second polishing [nm / min] / polishing rate for 20-second polishing [nm / min]) × 100

[0090]

Claims

1. A slurry comprising abrasive grains and water, wherein the abrasive grains include cerium oxide particles, and in an X-ray diffraction pattern of the cerium oxide particles, a peak of maximum intensity existing in a range of diffraction angle 2θ = 27.000 to 29.980 deg has a peak line width Wa at 10% of the maximum intensity and a peak line width Wb at 50% of the maximum intensity, and the ratio Wa / Wb is 2.50 to 3.

30.

2. The slurry of claim 1, wherein the ratio Wa / Wb is between 2.70 and 3.

20.

3. The slurry according to claim 1, wherein the abrasive grains have an average particle size of 200 to 400 nm.

4. The slurry according to claim 1, wherein the content of said abrasive grains is 0.01 to 10.00 mass %.

5. The slurry of claim 1, wherein the pH is from 1.00 to 7.

00.

6. The slurry of claim 1 used to polish a surface comprising silicon oxide.

7. A polishing method comprising a step of polishing a surface to be polished with the slurry according to any one of claims 1 to 6.

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