Slurry and polishing method

Abstract

A slurry contains abrasive grains and water, wherein the abrasive grains contain cerium oxide particles, and the product P of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane in the X-ray diffraction measurement of the cerium oxide particles, and the crystallite diameter D of the (111) plane of the cerium oxide particles is 7.5-11.0 nm. Also provided is a polishing method comprising a step for polishing a surface to be polished using the slurry.

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] The present disclosure relates to the following items [1] to [9]. [1] A slurry containing abrasive grains and water, wherein the abrasive grains include cerium oxide particles, and wherein the product P of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane in X-ray diffraction measurement of the cerium oxide particles and the crystallite diameter D of the (111) plane of the cerium oxide particles is 7.5 to 11.0 nm. [2] The slurry according to item [1], wherein the ratio R is 0.220 to 0.330. [3] The slurry according to item [1] or [2], wherein the ratio R is 0.265 or greater. [4] The slurry according to any one of items [1] to [3], wherein the crystallite diameter D is 25.0 to 35.0 nm. [5] The slurry according to any one of items [1] to [4], wherein the product P is 8.5 to 10.0 nm. [6] The slurry according to any one of [1] to [5], wherein the content of the abrasive grains is 0.01 to 10.00 mass %. [7] The slurry according to any one of [1] to [6], wherein the pH is less than 7.00. [8] The slurry according to any one of [1] to [7], which is used for polishing a surface to be polished that contains silicon oxide. [9] A polishing method comprising a step of polishing a surface to be polished using the slurry according to any one of [1] to [8].

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

[0011] <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.

[0012] 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.

[0013] <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.

[0014] In the slurry according to this embodiment, the abrasive grains contain cerium oxide particles, and the product P (ratio R × crystallite diameter D) of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane in X-ray diffraction measurement of the cerium oxide particles (peak intensity of the (200) plane / peak intensity of the (111) plane) and the crystallite diameter D of the (111) plane of the cerium oxide particles is 7.5 to 11.0 nm.

[0015] The slurry according to this embodiment can achieve a high polishing rate for insulating materials, for example, a high polishing rate for silicon oxide. In the blanket wafer evaluation method described in the Examples below, the slurry according to this embodiment can achieve a polishing rate for insulating materials (e.g., silicon oxide) of, for example, 450 nm / min or more (preferably, 500 nm / min or more, 600 nm / min or more, 700 nm / min or more, 800 nm / min or more, 900 nm / min or more, etc.).

[0016] According to one aspect of the slurry of this embodiment, in the patterned wafer evaluation method described in the examples below, a polishing rate of an insulating material (e.g., silicon oxide) of, for example, 100 nm / min or more (preferably, 200 nm / min or more, 300 nm / min or more, 500 nm / min or more, 800 nm / min or more, 1000 nm / min or more, 1200 nm / min or more, 1400 nm / min or more, 1500 nm / min or more, etc.) can be obtained.

[0017] The factors that enable a high polishing rate for insulating materials are not entirely clear, but are presumed to be as follows. However, the factors are not limited to the following. Specifically, the larger the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of a cerium oxide particle, the more the (200) plane, which has a high reactivity to insulating materials, dominates over the (111) plane, resulting in improved chemical polishing performance. However, the smaller the ratio R, the more the (111) plane, which has a high physical strength, dominates over the (200) plane, resulting in improved physical polishing performance. Furthermore, with regard to the crystallite diameter D of the (111) plane of a cerium oxide particle, the fewer grain boundaries there are and the less likely the particles are to crack as polishing progresses, resulting in improved physical polishing performance. However, if the crystallite diameter D is too large, the particles become too hard, making them less likely to crack and exposing new, highly reactive crystal planes (i.e., insufficient chemical reactivity). Therefore, the polishing rate for insulating materials can be adjusted by balancing the cerium oxide particle ratio R and the crystallite diameter D. It is presumed that when the product P of the cerium oxide particle ratio R and the crystallite diameter D is within a specific range, both physical and chemical polishing performances can be achieved, resulting in a good polishing rate for insulating materials.

[0018] According to one aspect of the slurry of this embodiment, a low polishing rate for the stopper material can be obtained, for example, a low polishing rate for silicon nitride can be obtained. According to one aspect of the slurry of this embodiment, in the blanket wafer evaluation method described in the examples below, a polishing rate for the stopper material (e.g., silicon nitride) of, for example, 500 nm / min or less (preferably, 400 nm / min or less, 300 nm / min or less, 200 nm / min or less, 150 nm / min or less, 130 nm / min or less, 120 nm / min or less, 110 nm / min or less, etc.) can be obtained.

[0019] According to one aspect of the slurry of this embodiment, it is possible to obtain a high polishing selectivity ratio of the insulating material to the stopper material (polishing rate of the insulating material / polishing rate of the stopper material), and for example, it is possible to obtain a high polishing selectivity ratio of silicon oxide to silicon nitride (polishing rate of silicon oxide / polishing rate of silicon nitride). According to one aspect of the slurry of this embodiment, in the blanket wafer evaluation method described in the examples below, it is possible to obtain, for example, a polishing selectivity of 2.0 or more (preferably 3.0 or more, 4.0 or more, 5.0 or more, 5.5 or more, 6.0 or more, etc.).

[0020] According to this embodiment, it is possible to provide a method for adjusting a polishing rate, in which the polishing rate is adjusted based on the product P of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particle and the crystallite diameter D of the (111) plane of the cerium oxide particle. According to this embodiment, it is possible to provide a method for selecting abrasive grains, in which abrasive grains containing cerium oxide particles are selected based on the product P of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particle and the crystallite diameter D of the (111) plane of the cerium oxide particle. According to this embodiment, it is possible to provide a slurry for use in polishing a polished surface including an insulating material, and it is possible to provide a slurry for use in polishing a polished surface including silicon oxide. According to this embodiment, it is possible to provide a slurry for use in a substrate surface planarization process, which is a semiconductor device manufacturing technology. According to this embodiment, it is possible to provide a slurry for use in a planarization process of an STI insulating material, a premetal 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. Examples of particles other than cerium oxide particles include silicon oxide (silica) particles, aluminum oxide (alumina) particles, silicon nitride particles, zirconium oxide (zirconia: yttria-added zirconia particles, etc.) particles, titanium oxide (titania) particles, yttrium oxide (yttria) particles, silicon carbide particles, diamond particles, and polymer particles. The abrasive grains may be core-shell particles containing a core particle and cerium oxide particles fixed to the surface of the core particle so as to cover at least a portion of the core particle, or may not be core-shell 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). The content of cerium oxide (cerium oxide particles) satisfying at least one of the ranges of the ratio R, the crystallite diameter D, and the product P, described below, may be within the above-mentioned ranges based on the total mass of the abrasive grains (the total mass of the abrasive grains contained in the slurry). When the abrasive grains further contain a component other than cerium oxide, the component other than cerium oxide may be a cerium compound other than cerium oxide, or may be a compound containing a rare earth element other than cerium (e.g., a lanthanoid element). The abrasive grains may be composite oxide particles of cerium oxide and a compound containing a rare earth element other than cerium (e.g., a lanthanoid element), but do not necessarily have to be composite oxide particles of cerium oxide and a compound containing a rare earth element other than cerium (e.g., a lanthanoid element).

[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, cerium oxalate, and cerium acetate. 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, cerium oxalate, and cerium acetate) 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," from the viewpoint of easily achieving a high polishing rate for insulating materials, or the "carbonyl substitution method," from the viewpoint of more easily achieving a high polishing rate for insulating materials.

[0027] In the slurry according to this embodiment, the abrasive grains contain cerium oxide particles, and the product P of the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane in X-ray diffraction measurement of the cerium oxide particles and the crystallite diameter D of the (111) plane of the cerium oxide particles is 7.5 to 11.0 nm. The ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane and the crystallite diameter D of the (111) plane of the cerium oxide particles can be derived from data obtained by powder X-ray diffraction (XRD) of the cerium oxide particles. The crystallite diameter D of the (111) plane of the cerium oxide particles is calculated from the peak of the (111) plane in the X-ray diffraction pattern (XRD chart) obtained by XRD of the cerium oxide particles using Equation (1). In Equation (1), K is the Schrrer constant, and 0.94 is used. λ is the wavelength of the incident X-rays, and 0.15418 nm is used for CuKα radiation. B is the half-width (unit: radian) of the peak of the (111) plane. b is the width standard material LaB manufactured by NIST, measured using the same X-ray diffraction device. ６ The half-width (unit: radian) of the peak when measuring (SRM660c). θ is the Bragg angle of the (111) plane.

[0028] The ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles may be 0.200 or more, more than 0.200, 0.210 or more, 0.220 or more, 0.230 or more, 0.240 or more, 0.250 or more, more than 0.250, 0.260 or more, 0.265 or more, 0.270 or more, 0.280 or more, 0.290 or more, 0.300 or more, or more than 0.300, from the viewpoint of easily improving the chemical reactivity of the cerium oxide particles and easily improving the polishing rate for insulating materials. The ratio R may be 0.350 or less, less than 0.350, 0.340 or less, 0.330 or less, 0.320 or less, or 0.310 or less, from the viewpoint of easily improving the physical strength of the cerium oxide particles and easily improving the polishing rate for insulating materials. The ratio R may be 0.300 or less, 0.290 or less, 0.280 or less, 0.270 or less, less than 0.270, 0.260 or less, 0.250 or less, or 0.240 or less. The ratio R may be 0.200 to 0.350, 0.200 to 0.330, 0.200 to 0.310, 0.220 to 0.350, 0.220 to 0.330, 0.220 to 0.310, 0.250 to 0.350, 0.250 to 0.330, 0.250 to 0.310, 0.290 to 0.350, 0.290 to 0.330, or 0.290 to 0.310.

[0029] The crystallite diameter D of the (111) plane of the cerium oxide particles may be 20.0 nm or more, 22.0 nm or more, 23.0 nm or more, 24.0 nm or more, 25.0 nm or more, 26.0 nm or more, 27.0 nm or more, 28.0 nm or more, or 29.0 nm or more, from the viewpoint of easily increasing the physical strength of the cerium oxide particles and easily improving the polishing rate of insulating materials. The crystallite diameter D may be 30.0 nm or more, 31.0 nm or more, 32.0 nm or more, or 33.0 nm or more. From the viewpoint of easily improving the chemical reactivity of the cerium oxide particles and easily improving the polishing rate of the insulating material, the crystallite diameter D may be 55.0 nm or less, 50.0 nm or less, 45.0 nm or less, 40.0 nm or less, less than 40.0 nm, 39.0 nm or less, 38.0 nm or less, 37.0 nm or less, 36.0 nm or less, 35.0 nm or less, less than 35.0 nm, 34.0 nm or less, or 33.0 nm or less. The crystallite diameter D may be 32.0 nm or less, 31.0 nm or less, 30.0 nm or less, or less than 30.0 nm. From these viewpoints, the crystallite diameter D may be 20.0 to 55.0 nm, 20.0 to 50.0 nm, 20.0 to 40.0 nm, 20.0 to 35.0 nm, 20.0 nm to 33.0 nm, 25.0 to 55.0 nm, 25.0 to 50.0 nm, 25.0 to 40.0 nm, 25.0 to 35.0 nm, 25.0 nm to 33.0 nm, 29.0 to 55.0 nm, 29.0 to 50.0 nm, 29.0 to 40.0 nm, 29.0 to 35.0 nm, or 29.0 nm to 33.0 nm.

[0030] The above-mentioned numerical range for the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles can be arbitrarily combined with the above-mentioned numerical range for the crystallite diameter D of the (111) plane of the cerium oxide particles. For example, the slurry according to this embodiment may be such that the abrasive grains contain cerium oxide particles, and the crystallite diameter D of the (111) plane of the cerium oxide particles is 0.220 to 0.330 and the crystallite diameter D of the (111) plane of the cerium oxide particles is 25.0 to 35.0.

[0031] Methods for adjusting the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles and the crystallite diameter D of the (111) plane of the cerium oxide particles include changing the composition of the raw materials, changing the method for preparing the raw materials, changing the firing temperature, firing time, etc. when firing the raw materials in a firing method, and changing the pulverization technique, conditions, etc. when pulverizing the cerium oxide particles. These methods may be used alone or in combination.

[0032] The cerium oxide particles to be measured by XRD to obtain the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles and the crystallite diameter D of the (111) plane of the cerium oxide particles may be recovered by drying (drying up) the slurry, or by separating and removing components other than the cerium oxide particles from the dried product. When the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles and the crystallite diameter D of the (111) plane of the cerium oxide particles do not change during the preparation of the slurry, the cerium oxide particles to be measured by XRD may be cerium oxide particles before being mixed with other components such as water.

[0033] The product P of the ratio R of cerium oxide particles and the crystallite diameter D may be 7.6 nm or more, 7.8 nm or more, 8.0 nm or more, 8.2 nm or more, 8.4 nm or more, 8.5 nm or more, 8.6 nm or more, 8.7 nm or more, 8.8 nm or more, or 8.9 nm or more, from the viewpoint that the chemical reactivity and physical strength of the cerium oxide particles are sufficiently high and the polishing rate for the insulating material is likely to be improved; and from the same viewpoint, it may be 10.8 nm or less, 10.6 nm or less, 10.5 nm or less, 10.4 nm or less, 10.2 nm or less, 10.0 nm or less, 9.8 nm or less, 9.6 nm or less, 9.5 nm or less, 9.4 nm or less, 9.3 nm or less, 9.2 nm or less, 9.1 nm or less, or 9.0 nm or less. From these perspectives, the product P may be 7.5 to 10.5 nm, 7.5 to 10.0 nm, 7.5 to 9.5 nm, 7.5 to 9.0 nm, 8.0 to 11.0 nm, 8.0 to 10.5 nm, 8.0 to 10.0 nm, 8.0 to 9.5 nm, 8.0 to 9.0 nm, 8.5 to 11.0 nm, 8.5 to 10.5 nm, 8.5 to 10.0 nm, 8.5 to 9.5 nm, or 8.5 to 9.0 nm.

[0034] Methods for adjusting the product P of the ratio R of cerium oxide particles and the crystallite diameter D include changing the composition of the raw materials; changing the method for preparing the raw materials; changing the calcination temperature, calcination time, etc. when calcining the raw materials in a calcination method; and changing the pulverization method, conditions, etc. when pulverizing the cerium oxide particles. These methods may be used alone or in combination. More specifically, for example, when wet-pulverizing cerium oxide particles, by wet-pulverizing the cerium oxide particles so that the average particle size of the resulting cerium oxide particles is small, the ratio R can be reduced without significantly changing the crystallite diameter D, and therefore the product P can be adjusted by adjusting the conditions for wet-pulverization.

[0035] The average particle size D50 of the abrasive grains or the average particle size D50 of the cerium oxide particles may be in the following ranges: From the viewpoint of easily achieving a high removal rate for insulating materials, the average particle size D50 may be 80 nm or more, more than 80 nm, 90 nm or more, 100 nm or more, 120 nm or more, 140 nm or more, 150 nm or more, 150 nm or more, 160 nm or more, 170 nm or more, 180 nm or more, 190 nm or more, or 200 nm or more. From the viewpoint of easily reducing scratches caused by polishing, the average particle size D50 may be 600 nm or less, 500 nm or less, less than 500 nm, 400 nm or less, less than 400 nm, 350 nm or less, 300 nm or less, less than 300 nm, 290 nm or less, 280 nm or less, 270 nm or less, 260 nm or less, 250 nm or less, 240 nm or less, 230 nm or less, 220 nm or less, 210 nm or less, or 200 nm or less. From these viewpoints, the average particle size D50 may be 100 to 600 nm, 100 to 500 nm, 100 to 400 nm, 100 to 300 nm, 100 to 250 nm, 100 to 220 nm, 150 to 600 nm, 150 to 500 nm, 150 to 400 nm, 150 to 300 nm, 150 to 250 nm, 150 to 220 nm, 180 to 600 nm, 180 to 500 nm, 180 to 400 nm, 180 to 300 nm, 180 to 250 nm, or 180 to 220 nm.

[0036] The average particle size D50 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 D50 (volume mean diameter) may be measured by adjusting the abrasive grain content or the cerium oxide particle content to an appropriate content by diluting the slurry with water. For example, in the case of "SYNC," a product name manufactured by Microtrac-Bell Corporation, the content may 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 as a first liquid containing abrasive grains and water, and a second liquid containing additives and water, the first liquid may be diluted with water to adjust the abrasive grain content to an appropriate content, and the average particle size D50 may be measured.

[0037] Methods for adjusting the average particle diameter D50 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.

[0038] 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%. The content of cerium oxide particles in the slurry may be within the same range as the above-mentioned numerical range of the content of the abrasive grains.

[0039] (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.

[0040] 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%.

[0041] (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).

[0042] 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.

[0043] Examples of the polyoxyalkylene compound include polyalkylene glycols and polyoxyalkylene derivatives.

[0044] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutylene glycol.

[0045] The polyoxyalkylene derivative is, for example, a compound in which a functional group or a substituent has been introduced into a polyalkylene glycol, or a compound in which a polyalkylene oxide has been 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.).

[0046] 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. Note that polymers that fall under the above-mentioned polyoxyalkylene compounds are not included in the "water-soluble polymer."

[0047] 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.

[0048] 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% by mass or more, 0.005% by mass or more, 0.010% by mass or more, 0.020% by mass or more, 0.030% by mass or more, 0.040% by mass or more, 0.050% by mass or more, 0.060% by mass or more, 0.070% by mass or more, or 0.075% by 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%.

[0049] (pH) The pH of the slurry according to this embodiment may be in the following range. From the viewpoint of easily achieving a high polishing rate for insulating materials, the pH may be 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, or 4.80 or less. When the pH of the slurry is less than 7 (i.e., acidic) and the product P of the cerium oxide particles contained in the slurry is within the above-mentioned range, the insulating material can be polished at a higher polishing rate than a slurry containing cerium oxide particles having a pH of 7 or more and a product P within the above-mentioned range, and a slurry containing cerium oxide particles having a pH of less than 7 and a product P outside the above-mentioned range. When the pH of the slurry is less than 7, the surfaces of the cerium oxide particles are positively charged and the surface of the insulating material is negatively charged. The electrostatic attraction between the cerium oxide particles and the insulating material increases the proportion of cerium oxide particles that contribute to polishing. As a result, the insulating material can be polished at a higher polishing rate. The pH may be 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, 4.20 or less, 4.10 or less, 4.00 or less, or 3.90 or less. From the viewpoint of easily obtaining a high removal rate for insulating materials, 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, 3.10 or more, 3.20 or more, 3.30 or more, 3.40 or more, 3.50 or more, more than 3.50, 4.00 or more, more than 4.00, 4.10 or more, or 4.20 or more. The pH may be 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 these viewpoints, the pH may be 1.00 or more and less than 7.00, 1.00 to 6.00, 1.00 to 5.00, 1.00 to 4.80, 2.00 or more and less than 7.00, 2.00 to 6.00, 2.00 to 5.00, 2.00 to 4.80, 3.00 or more and less than 7.00, 3.00 to 6.00, 3.00 to 5.00, 3.00 to 4.80, 3.30 or more and less than 7.00, 3.30 to 6.00, 3.30 to 5.00, 3.30 to 4.80, 4.00 or more and less than 7.00, 4.00 to 6.00, 4.00 to 5.00, or 4.00 to 4.80. The pH of the slurry is defined as the pH at a liquid temperature of 25°C.

[0050] 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.

[0051] 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.

[0052] (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.

[0053] 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.

[0054] <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.

[0055] 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.

[0056] 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.

[0057] The slurry according to this embodiment can be used to polish an insulating material (e.g., silicon oxide) formed on a substrate and remove excess portions, thereby eliminating unevenness on the surface of the insulating material and obtaining a smooth surface over the entire surface of the insulating material.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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. Some of the constituent elements of such silicon oxide may be substituted with carbon atoms, nitrogen atoms, phosphorus atoms, boron atoms, etc.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] <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.

[0067] 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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited to the following examples.

[0072] <Slurry Preparation> (Example 1) 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 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 700°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.

[0073] 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 wet-pulverized using a wet micronization device "Starburst Lab HJP-25005" manufactured by Sugino Machine Corporation (pressure 245 MPa) to obtain a dispersion. The wet-pulverization was carried out so that the average particle size D50 of the crushed product (cerium oxide particles) in the dispersion was 400 nm. This dispersion was centrifuged using a centrifuge "himac CR7" manufactured by Hitachi Koki Co., Ltd. (rotation speed 2000 rpm), and a dispersion containing cerium oxide particles was obtained as the liquid remaining at the top of the container after centrifugation. The centrifugation was carried out so that the average particle size D50 of the cerium oxide particles in the resulting dispersion was 200 nm. The cerium oxide particles were then recovered from the dispersion.

[0074] The cerium oxide particles (abrasive grains), pure water, and polyglycerin (trade name: Polyglycerin #750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) were mixed in a mass ratio of 2.000:97.925:0.075 to obtain a polishing slurry. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0075] Example 2 A polishing slurry was obtained in the same manner as in Example 1, except that the wet pulverization was carried out so that the average particle size D50 of the pulverized material (cerium oxide particles) in the dispersion liquid was 300 nm. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0076] Example 3 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 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 using XRD, and it was confirmed to be a cerium oxide powder.

[0077] 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 wet-pulverized using a wet micronization device "Starburst Lab HJP-25005" manufactured by Sugino Machine Corporation (pressure 245 MPa) to obtain a dispersion. The wet-pulverization was carried out so that the average particle size D50 of the crushed product (cerium oxide particles) in the dispersion was 400 nm. This dispersion was centrifuged using a centrifuge "himac CR7" manufactured by Hitachi Koki Co., Ltd. (rotation speed 2000 rpm), and a dispersion containing cerium oxide particles was obtained as the liquid remaining at the top of the container after centrifugation. The centrifugation was carried out so that the average particle size D50 of the cerium oxide particles in the resulting dispersion was 200 nm. The cerium oxide particles were then recovered from the dispersion.

[0078] The cerium oxide particles (abrasive grains), pure water, and polyglycerin (trade name: Polyglycerin #750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) were mixed in a mass ratio of 2.000:97.925:0.075 to obtain a polishing slurry. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0079] Example 4 A polishing slurry was obtained in the same manner as in Example 2, except that the firing temperature was changed to 850° C. and the firing time was changed to 3 hours. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0080] Comparative Example 1 A polishing slurry was obtained in the same manner as in Example 1, except that the cerium carbonate powder was changed to cerium acetate (Kanto Chemical Co., Inc., product name: cerium (III) acetate monohydrate, 4N (cerous acetate)). The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0081] Comparative Example 2 A polishing slurry was obtained in the same manner as in Example 1, except that the cerium carbonate powder was changed to cerium acetate (Kanto Chemical Co., Inc., product name: cerium (III) acetate monohydrate, 4N (cerous acetate)) and the firing temperature was changed to 850° C. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0082] Comparative Example 3 A polishing slurry was obtained in the same manner as in Example 3, except that the wet pulverization was carried out so that the average particle size D50 of the pulverized material (cerium oxide particles) in the dispersion liquid was 300 nm. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0083] Comparative Example 4 A polishing slurry was obtained in the same manner as in Example 3, except that the firing temperature was changed to 900° C. The average particle size D50 of the cerium oxide particles in the slurry was 200 nm.

[0084] <Average Particle Size> The average particle size D50 of the cerium oxide particles was measured as the volume mean diameter (MV) using a laser diffraction particle size distribution analyzer (manufactured by Microtrac Bell Corporation, product name "SYNC", particle refractive index: 2.20).

[0085] <Peak Intensity Ratio and Crystallite Diameter D> Each of the above slurries was placed in a commercially available evaporating dish and then dried for 24 hours in a vacuum dryer (manufactured by Yamato Scientific Co., Ltd., ADP200, 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. From the obtained X-ray diffraction pattern, the ratio R of the peak intensity of the (200) plane to the peak intensity of the (111) plane of the cerium oxide particles (peak intensity of the (200) plane / peak intensity of the (111) plane) was calculated. Furthermore, the crystallite diameter D of the (111) plane was calculated based on the above-mentioned formula (1). In the formula (1), the Scherrer constant K is 0.94, the wavelength λ of the X-ray is 0.15418 nm, B is the half-width (unit: radian) of the peak of the (111) plane, and b is the half-width of the standard material LaB manufactured by NIST using the same X-ray diffraction apparatus. ６The Bragg angle θ is the half value of the (111) peak position (2θ).

[0086] [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

[0087] <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.

[0088] <CMP Evaluation> Using each of the above slurries, CMP evaluation was carried out under the following conditions.

[0089] (Preparation of wafers for evaluation) As blanket wafers (BKW), a 20 mm x 20 mm unpatterned wafer having a silicon oxide film (TEOS, initial film thickness: 1000 nm) on its surface and a 20 mm x 20 mm unpatterned wafer having a silicon nitride film (initial film thickness: 200 nm) on its surface were prepared.

[0090] A test pattern wafer (PTW) (model number: Sematech 864, manufactured by Advantec Co., Ltd., 20 mm x 20 mm) was prepared. The test pattern wafer (PTW) had a silicon oxide film (initial film thickness: 600 nm) with a concave-convex pattern on its surface. The convex portions (line portions) had an initial step height that was 500 nm higher than the concave portions (space portions). The convex portions were provided with a silicon nitride film (initial film thickness: 140 nm) as a stopper for the silicon oxide film, assuming evaluation for shallow trench isolation. The pattern wafer had multiple 20 mm x 20 mm die units, and each die unit had multiple 4 mm x 4 mm unit areas. The pattern wafer has a 4 mm x 4 mm unit area and an area having a parallel line pattern with a pitch of 100 μm width and a Line / Space (L / S) of 10 μm / 90 μm (protrusion density: 10%) to 90 μm / 10 μm (protrusion density: 90%) in 10 μm increments.

[0091] (Polishing conditions) Polishing device: small desktop polishing machine ("IMPTECH 10 DVT" manufactured by Engis Japan Co., Ltd.) Polishing cloth: polishing pad made of porous urethane resin (manufactured by DuPont (Dow), model number: IK4250H) Plate rotation speed: 120 min －１ Polishing pressure: 50 kPa Polishing liquid supply rate: 5 ml / min

[0092] (Polishing Procedure) Blanket wafers were polished for 30 seconds. For patterned wafers, the polishing time was set within the range of 20 to 60 seconds depending on the polishing rate evaluated for the blanket wafer, and was the time during which the silicon nitride film underlying the silicon oxide film was not exposed in the convex portions in the region of L / S = 20 μm / 80 μm. Polishing was performed for that polishing time.

[0093] (Evaluation of Polishing Rate) The change in film thickness of the film to be polished before and after polishing was measured using an optical interference film thickness measuring device (trade name: AFT-5100, manufactured by Nanometrics Japan Co., Ltd.) as follows, to obtain the polishing rate. The results are shown in Table 1.

[0094] For blanket wafers, the change in film thickness was measured at the center of the wafer, and the average value of the changes in film thickness over a 30-second polishing period was taken as the polishing rate for the blanket wafer.

[0095] For the patterned wafer, the amount of change in film thickness at the convex portions in the region of L / S = 20 μm / 80 μm was measured to obtain the polishing rate of the patterned wafer. The amount of change in film thickness at one location in the center of one unit area (4 mm × 4 mm) of L / S = 20 μm / 80 μm was measured.

[0096]

Claims

1. A slurry comprising abrasive grains and water, the abrasive grains including cerium oxide particles, and a product P of a ratio R of a peak intensity of a (200) plane to a peak intensity of a (111) plane of the cerium oxide particles in an X-ray diffraction measurement and a crystallite diameter D of the (111) plane of the cerium oxide particles is 7.5 to 11.0 nm.

2. The slurry of claim 1, wherein said ratio R is between 0.220 and 0.

330.

3. The slurry of claim 1, wherein said ratio R is greater than or equal to 0.

265.

4. The slurry according to claim 1, wherein the crystallite size D is 25.0 to 35.0 nm.

5. The slurry of claim 1, wherein the product P is between 8.5 and 10.0 nm.

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

7. The slurry of claim 1, wherein the pH is less than 7.

00.

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

9. A polishing method comprising a step of polishing a surface to be polished with the slurry according to any one of claims 1 to 8.

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