CMP polishing liquid, CMP polishing liquid set and polishing method

Abstract

Provided is a polishing liquid for CMP, wherein: the polishing liquid contains abrasive grains, an additive, and water; the abrasive grains contain cerium-based particles; the additive contains (A1) a 4-pyrone-based compound represented by general formula (1) and (B) saturated monocarboxylic acid; and the pH of the polishing liquid exceeds 4.0. Also provided is a polishing liquid for CMP, wherein: the polishing liquid contains abrasive grains, an additive, and water; the abrasive grains contain cerium-based particles; the additive contains (A2) picolinic acid and (B) saturated monocarboxylic acid; and the pH of the polishing liquid exceeds 4.0.　(In the formula, X11, X12, and X13 are each independently a hydrogen atom or a monovalent substituent group.)

Description

[Technical field]

[0001] The present disclosure relates to a polishing liquid for CMP (chemical mechanical polishing), a polishing liquid set for CMP, a polishing method, and the like. [Background technology]

[0002] In the field of semiconductor manufacturing, as the performance of ultra-LSI devices improves, it is becoming increasingly difficult to achieve both high integration and high speed using miniaturization technology, which is an extension of conventional technology. Therefore, technology is being developed to achieve high integration in the vertical direction (i.e., technology to create multiple layers of wiring) while continuing to miniaturize semiconductor elements.

[0003] One of the most important technologies in the process of manufacturing devices with multi-layered wiring is CMP technology. CMP technology is a technology to flatten the surface of a substrate obtained by forming a thin film on a substrate by chemical vapor deposition (CVD) or other methods. For example, flattening by CMP is essential to ensure the depth of focus in lithography. If the surface of the substrate is uneven, it may cause inconveniences such as making it impossible to focus in the exposure process or not being able to form a fine wiring structure sufficiently. In addition, CMP technology is also applied to the process of forming element isolation (inter-element isolation; STI: shallow trench isolation) regions by polishing plasma oxide films (BPSG, HDP-SiO2, p-TEOS, etc.) in the device manufacturing process; the process of forming ILD films (interlayer insulating films; insulating films that electrically insulate metal members (wiring, etc.) from each other in the same layer); and the process of flattening plugs (e.g. Al / Cu plugs) after embedding a film containing silicon oxide in metal wiring.

[0004] CMP is usually performed using an apparatus capable of supplying a polishing liquid onto a polishing pad. The surface of the substrate is polished by pressing the substrate against the polishing pad while supplying the polishing liquid between the substrate surface and the polishing pad. Thus, the polishing liquid is one of the elemental technologies in the CMP technology, and various polishing liquids have been developed to obtain high-performance polishing liquids (for example, see Patent Document 1 below).

[0005] Among the processes to which the CMP technology as described above is applied, in particular, in the CMP process of an ILD film, it is necessary to polish silicon oxide at a high polishing rate. Therefore, in the CMP process of an ILD film, a silica-based polishing liquid (polishing liquid using abrasive grains containing silica-based particles) having a high polishing rate is mainly used (see, for example, Patent Document 2 below). However, with a silica-based polishing liquid, it tends to be difficult to control polishing scratches, which are the cause of defects. In addition, with the recent miniaturization of wiring, it is desirable to reduce polishing scratches in the CMP process of an ILD film, but unlike the CMP process of an insulating film for an element isolation region, finishing mirror polishing is generally not performed. Therefore, the use of a cerium-based polishing liquid (polishing liquid using abrasive grains containing cerium-based particles), which causes fewer polishing scratches than a silica-based polishing liquid, is being considered (see, for example, Patent Document 3 below). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-288537 A [Patent Document 2] Japanese Patent Application Publication No. 9-316431 [Patent Document 3] Japanese Patent Application Publication No. 10-102038 Summary of the Invention [Problem to be solved by the invention]

[0007] In polishing using a polishing liquid for CMP, it is sometimes required to obtain a high polishing rate ratio of silicon oxide on convex portions of a patterned wafer having a fine concave-convex pattern composed of convex portions (e.g., line portions) and concave portions (e.g., space portions) to silicon oxide on a blanket wafer having no concave-convex pattern.

[0008] An object of one aspect of the present disclosure is to provide a polishing liquid for CMP capable of achieving a high polishing rate ratio of silicon oxide on a convex portion of a patterned wafer to silicon oxide on a blanket wafer. Another object of the present disclosure is to provide a polishing liquid set for obtaining the polishing liquid for CMP. Still another object of the present disclosure is to provide a polishing method using the polishing liquid for CMP or the polishing liquid set for CMP. [Means for solving the problem]

[0009] When polishing the convex portions of a patterned wafer, the pressure applied to the convex portions during polishing tends to be greater than that applied to the main surface of a blanket wafer that does not have a concave-convex pattern. Therefore, it is expected that the polishing rate ratio of the convex portions of the patterned wafer will be higher than that of the blanket wafer. However, the present inventors have found that when a CMP polishing liquid using a saturated monocarboxylic acid to improve the dispersibility of abrasive grains, etc., has a pH of more than 4.0, a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer may not be obtained.

[0010] The present disclosure relates in some aspects to the following items [1] to

[22] etc. [1] A polishing liquid for CMP comprising an abrasive grain, an additive, and water, wherein the abrasive grain comprises cerium-based particles, and the additive comprises (A1) a 4-pyrone-based compound represented by the following general formula (1) and (B) a saturated monocarboxylic acid, and wherein the pH exceeds 4.0. [ka] [where, X 11 , X12 and X 13 are each independently a hydrogen atom or a monovalent substituent. [2] The polishing liquid for CMP according to [1], wherein the component (A1) contains at least one member selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone, 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and 2-ethyl-3-hydroxy-4-pyrone. [3] The polishing slurry for CMP according to [1] or [2], wherein the content of the component (A1) is 0.001 to 5 mass %. [4] The polishing liquid for CMP according to any one of [1] to [3], wherein the component (B) contains propionic acid. [5] The polishing liquid for CMP according to any one of [1] to [4], wherein the content of the component (B) is 0.0001 to 5 mass %. [6] (C) The polishing liquid for CMP according to any one of [1] to [5], further comprising a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded. [7] The polishing liquid for CMP according to [6], wherein the component (C) contains ethylenedinitrilotetraethanol. [8] The polishing liquid for CMP according to [6] or [7], wherein the component (C) contains ethylenedinitrilotetrapropanol. [9] The polishing liquid for CMP according to any one of [1] to [8], wherein the additive further contains hydroxypyridine.

[10] The polishing liquid for CMP according to any one of [1] to [9], wherein the additive further contains L-histidine.

[11] The polishing liquid for CMP according to any one of [1] to

[10] , which has a pH of 8.0 or less.

[12] A polishing fluid for CMP comprising: an abrasive grain; an additive; and water, wherein the abrasive grain comprises cerium-based particles; the additive comprises (A2) picolinic acid and (B) a saturated monocarboxylic acid; and the fluid has a pH of greater than 4.0.

[13] The polishing slurry for CMP according to

[12] , wherein the content of the component (A2) is 0.001 to 5 mass %.

[14] The polishing liquid for CMP according to

[12] or

[13] , wherein the component (B) contains propionic acid.

[15] The polishing liquid for CMP according to any one of

[12] to

[14] , wherein the content of the component (B) is 0.0001 to 5 mass %.

[16] (C) The polishing liquid for CMP according to any one of

[12] to

[15] , further comprising a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

[17] The polishing liquid for CMP according to

[16] , wherein the component (C) contains ethylenedinitrilotetraethanol.

[18] The polishing liquid for CMP according to

[16] or

[17] , wherein the component (C) contains ethylenedinitrilotetrapropanol.

[19] The polishing liquid for CMP according to any one of

[12] to

[18] , which has a pH of 8.0 or less.

[20] A polishing liquid set for CMP, wherein the components of the polishing liquid for CMP according to any one of [1] to

[19] are stored separately as a first liquid and a second liquid, the first liquid containing the abrasive grains and water, and the second liquid containing at least one of the additives and water.

[21] A polishing method comprising a step of polishing a surface to be polished using the polishing liquid for CMP according to any one of [1] to

[19] , or the polishing liquid for CMP obtained by mixing the first liquid and the second liquid in the polishing liquid set for CMP according to

[20] .

[22] The polishing method described in

[21] , wherein the polished surface contains silicon oxide. Effect of the Invention

[0011] According to one aspect of the present disclosure, it is possible to provide a CMP polishing liquid capable of achieving a high polishing rate ratio of silicon oxide on a convex portion of a patterned wafer to silicon oxide on a blanket wafer. According to another aspect of the present disclosure, it is possible to provide a CMP polishing liquid set for obtaining the CMP polishing liquid. Furthermore, according to another aspect of the present disclosure, it is possible to provide a polishing method using the CMP polishing liquid or the CMP polishing liquid set. [Brief description of the drawings]

[0012] [Figure 1]It is a schematic cross-sectional view showing the process of polishing an ILD film.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described in detail.

[0014] In this specification, a numerical range indicated by "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. "A or more" of a numerical range means A and a range exceeding A. "A or less" of a numerical range means A and a range less than A. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a certain step's numerical range can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of other steps. In the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples. "A or B" means that either A or B may be included, or both may be included. The materials exemplified in this specification can be used alone or in combination of two or more, unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances corresponding to each component in the composition, unless otherwise specified, when there are a plurality of substances corresponding to each component in the composition. The terms "layer" or "film" include, in addition to the structure formed over the entire surface when observed as a plan view, the structure formed partially. The term "step" includes not only an independent step but also a step in which, even if it cannot be clearly distinguished from other steps, the intended action of the step is achieved.

[0015] <Polishing Liquid for CMP> The CMP polishing liquid according to this embodiment (first and second embodiments, hereinafter the same) is a CMP polishing liquid (hereinafter, sometimes simply referred to as "polishing liquid") containing abrasive grains, an additive, and water. The abrasive grains include cerium-based particles (particles containing a cerium-based compound). The additive of the polishing liquid according to the first embodiment includes (A1) a 4-pyrone-based compound (component (A1)) represented by the following general formula (1) and (B) a saturated monocarboxylic acid (component (B)). The additive of the polishing liquid according to the second embodiment includes (A2) picolinic acid (component (A2)) and (B) a saturated monocarboxylic acid (component (B)). The additive of the polishing liquid according to this embodiment may include component (A1), component (A2), and component (B). The pH of the CMP polishing liquid according to this embodiment exceeds 4.0.

[0016] [ka] [where, X 11 , X 12 and X 13 are each independently a hydrogen atom or a monovalent substituent.

[0017] The polishing liquid according to this embodiment can achieve a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer having a fine concave-convex pattern composed of convex portions (e.g., line portions) and concave portions (e.g., space portions) to silicon oxide on a blanket wafer having no concave-convex pattern, for example, a high polishing rate ratio of silicon oxide on the convex portions in a region of the patterned wafer where L / S=20 μm / 80 μm is achieved to silicon oxide on a blanket wafer having no concave-convex pattern. The polishing liquid according to this embodiment can achieve a polishing rate ratio of silicon oxide on the convex portions in a region of the patterned wafer where L / S=20 μm / 80 μm is achieved to silicon oxide on the blanket wafer in an evaluation method described in the examples below, for example, of 1.30 or more (preferably 1.50 or more, 1.60 or more, 1.80 or more, 2.00 or more, etc.).

[0018] The factors that enable a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer 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 polishing liquid of this embodiment, when the pH of the CMP polishing liquid using component (B) (saturated monocarboxylic acid) exceeds 4.0, the interaction between the polishing liquid and silicon oxide on the convex portions increases by using component (A1) or (A2) (for example, the chemical reaction (reaction derived from Si-O-Ce bonds) between the cerium-based particles in the polishing liquid and silicon oxide on the convex portions is promoted). This makes it possible to obtain a high polishing rate of silicon oxide on the convex portions, and therefore a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer can be obtained.

[0019] According to one aspect of the polishing liquid of this embodiment, high-speed polishing of silicon oxide on a blanket wafer not having a concave-convex pattern (e.g., a polishing rate of 100 nm / min or more (preferably 250 nm / min or more)) can be achieved, while a high polishing rate of silicon oxide on convex portions can be achieved in polishing an L / S=20 μm / 80 μm region on a patterned wafer.

[0020] In the process of forming an element isolation region, it is required to suppress the polishing rate of the silicon nitride film used as a stopper under the silicon oxide film, and high polishing selectivity of silicon oxide to silicon nitride (polishing rate of silicon oxide / polishing rate of silicon nitride) may be required. According to one aspect of the polishing liquid of this embodiment, it is possible to obtain a sufficiently small polishing rate of silicon nitride, and high polishing selectivity of silicon oxide to silicon nitride can be obtained. In this case, it is suitable for polishing when forming an element isolation region. According to one aspect of the polishing liquid of this embodiment, in the evaluation method described in the examples below, it is possible to obtain a polishing rate of silicon nitride of, for example, less than 2.0 nm / min (preferably less than 1.0 nm / min, etc.) on a blanket wafer.

[0021] The polishing liquid according to the present embodiment can be used for CMP of semiconductor wafer materials, for example, for polishing a silicon oxide film provided on the surface of a semiconductor wafer. The polishing liquid according to the present embodiment can be used in the CMP process of an ILD film. According to one aspect of the polishing liquid according to the present embodiment, it is possible to obtain a high polishing rate, suppress the aggregation of abrasive grains and the occurrence of polishing scratches, and obtain high flatness.

[0022] (Abrasive grain) The abrasive grains include cerium-based particles. By using cerium-based particles as the abrasive grains, it is easy to obtain a high removal rate of silicon oxide on the convex portions of the patterned wafer while reducing polishing scratches on the surface to be polished.

[0023] Examples of the cerium-based compound of the cerium-based particles include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The cerium-based particles may contain cerium oxide, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide at the convex parts of the patterned wafer (such as convex parts in the region of L / S=20 μm / 80 μm; the same applies below) to silicon oxide at the blanket wafer. By using cerium-based particles (cerium oxide particles) containing cerium oxide, it is easy to achieve a high polishing rate of silicon oxide at the convex parts of the patterned wafer, and it is easy to obtain a polished surface with few polishing scratches and excellent flatness.

[0024] The cerium oxide particles may include polycrystalline cerium oxide having grain boundaries. Such polycrystalline cerium oxide particles have the property of becoming finer during polishing and simultaneously revealing active surfaces one after another, and can maintain a high polishing rate for silicon oxide on the convex portions of the patterned wafer.

[0025] Examples of methods for producing cerium oxide particles include a calcination method and an oxidation method using hydrogen peroxide or the like. When calcination is performed, the temperature during calcination may be 350 to 900° C. When the produced cerium oxide particles are aggregated, the particles may be mechanically pulverized. The pulverization method may be, for example, dry pulverization using a jet mill or the like, or wet pulverization using a planetary bead mill or the like. As the jet mill, for example, one described in "Chemical Engineering Journal," Vol. 6, No. 5, (1980), pp. 527-532, can be used.

[0026] The zeta potential (surface potential) of the abrasive grains in the polishing liquid may be positive (the zeta potential may exceed 0 mV) from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex parts of the patterned wafer, and from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer having no uneven pattern. The zeta potential of the abrasive grains can be measured, for example, using a dynamic light scattering zeta potential measuring device (for example, manufactured by Beckman Coulter, Inc., product name: DelsaNano C). The zeta potential of the abrasive grains can be adjusted using an additive. For example, an abrasive grain having a positive zeta potential can be obtained by contacting the abrasive grains with an acid component (for example, acetic acid).

[0027] The average particle size of the abrasive grains may be 50 nm or more, 70 nm or more, 100 nm or more, more than 100 nm, 105 nm or more, 110 nm or more, 115 nm or more, 120 nm or more, 125 nm or more, 130 nm or more, 135 nm or more, or 140 nm or more, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex parts of the patterned wafer, and from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer having no uneven pattern. The average particle size of the abrasive grains may be 500 nm or less, 300 nm or less, 200 nm or less, 180 nm or less, 150 nm or less, 140 nm or less, 135 nm or less, 130 nm or less, 125 nm or less, or 120 nm or less, from the viewpoint of easily suppressing the occurrence of polishing scratches. From these viewpoints, the average particle size of the abrasive grains may be 50 to 500 nm, 50 to 200 nm, 50 to 150 nm, 70 to 500 nm, 70 to 200 nm, 70 to 150 nm, 100 to 500 nm, 100 to 200 nm, or 100 to 150 nm. By adjusting the average particle size of the abrasive grains, a high polishing rate and low scratch characteristics of silicon oxide according to the average particle size of the abrasive grains can be efficiently obtained.

[0028] The "average particle size of abrasive grains" refers to the median value of the volume distribution measured by a laser diffraction / scattering particle size distribution measuring device for a sample of a slurry in which the abrasive grains are dispersed, and can be measured using a device such as Microtrac MT3300EXII (trade name) manufactured by MicrotracBEL Corp. For example, a sample is prepared by dispersing the abrasive grains in water to adjust the content of the abrasive grains so that the content of the abrasive grains is 0.25% by mass based on the total mass of the sample, and this sample is set in the measuring device to measure the median value of the volume distribution. When measuring the particle size of the abrasive grains in the polishing liquid, a sample is prepared by adjusting the content of the abrasive grains in the polishing liquid so that the content of the abrasive grains is 0.25% by mass based on the total mass of the sample, and this sample can be used for measurement in the same manner.

[0029] The content of the abrasive grains may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of achieving an excellent balance between the polishing rate of silicon oxide on the convex parts of the patterned wafer and the dispersion stability of the abrasive grains. The content of the abrasive grains may be 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.15 mass% or more, 0.2 mass% or more, 0.25 mass% or more, 0.3 mass% or more, 0.5 mass% or more, 0.8 mass% or more, or 1 mass% or more. The content of the abrasive grains may be 10 mass% or less, 5 mass% or less, 3 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.5 mass% or less, 0.3 mass% or less, or 0.25 mass% or less. From these viewpoints, the content of the abrasive grains may be 0.01 to 10 mass%, 0.01 to 1 mass%, 0.01 to 0.5 mass%, 0.01 to 0.25 mass%, 0.05 to 10 mass%, 0.05 to 1 mass%, 0.05 to 0.5 mass%, 0.05 to 0.25 mass%, 0.1 to 10 mass%, 0.1 to 1 mass%, 0.1 to 0.5 mass%, or 0.1 to 0.25 mass%.

[0030] (Additives) [Component (A1): 4-pyrone compound] The additive for the polishing liquid according to the first embodiment contains a 4-pyrone-based compound represented by general formula (1) (hereinafter, sometimes simply referred to as "4-pyrone-based compound") as component (A1). It is presumed that the use of a 4-pyrone-based compound increases the interaction between the polishing liquid and silicon oxide, which tends to increase the polishing rate. In addition, although a 4-pyrone-based compound is an additive that can increase the interaction between the polishing liquid and silicon oxide, it does not have the effect of weakening repulsive forces such as electrostatic repulsive forces between abrasive grains, and is therefore thought to be able to suppress aggregation of abrasive grains.

[0031] A 4-pyrone compound is a compound represented by the following general formula (1), and has a structure in which a hydroxy group is bonded to the carbon atom adjacent to the carbon atom of a carbonyl group. A "4-pyrone compound" is a heterocyclic compound having a γ-pyrone ring (6-membered ring) that has an oxy group and a carbonyl group, and the carbonyl group is located at the 4-position relative to the oxy group. In a 4-pyrone compound, a hydroxy group is bonded to the carbon atom adjacent to the carboxy group in this γ-pyrone ring, and the other carbon atoms may be substituted with a substituent other than a hydrogen atom.

[0032] [ka]

[0033] In the formula, X 11 , X 12 and X 13 are each independently a hydrogen atom or a monovalent substituent. Examples of the monovalent substituent include an aldehyde group, a hydroxy group, a carboxy group, a carboxylate group, a sulfonic acid group, a phosphate group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, a nitro group, a hydrazine group, an alkyl group (e.g., an alkyl group having 1 to 8 carbon atoms), an aryl group (e.g., an aryl group having 6 to 12 carbon atoms), an alkenyl group (e.g., an alkenyl group having 1 to 8 carbon atoms), and the like. The alkyl group, the aryl group, and the alkenyl group may be substituted with OH, COOH, Br, Cl, I, NO2, or the like. X 11 , X 12 and X 13 When the aryl group has a monovalent substituent as X, the substituent may be attached to the carbon atom adjacent to the oxy group, i.e., X 11 and X 12 may be a substituent. X 11 , X 12 and X 13 At least two of may be hydrogen atoms.

[0034] The 4-pyrone-based compound may contain at least one selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone (also known as 3-hydroxy-2-methyl-4H-pyran-4-one, maltol), 5-hydroxy-2-(hydroxymethyl)-4-pyrone (also known as 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one, kojic acid), and 2-ethyl-3-hydroxy-4-pyrone (also known as 2-ethyl-3-hydroxy-4H-pyran-4-one), and may contain 3-hydroxy-2-methyl-4-pyrone, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the pattern wafer relative to silicon oxide in the blanket wafer, and easily suppressing aggregation of abrasive grains. The 4-pyrone-based compound may be used alone or in combination of two or more.

[0035] The 4-pyrone compound may be water-soluble. By using a compound having high solubility in water, a desired amount of additive can be dissolved well in the polishing liquid, and the effect of improving the polishing rate and suppressing the aggregation of abrasive grains can be achieved at a higher level. The solubility of the 4-pyrone compound in 100 g of water at room temperature (25° C.) may be 0.001 g or more, 0.005 g or more, 0.01 g or more, or 0.05 g or more. There is no particular upper limit to the solubility.

[0036] The content of the 4-pyrone compound may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer relative to silicon oxide in the blanket wafer: The content of the 4-pyrone compound may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.015 mass% or more, 0.02 mass% or more, 0.025 mass% or more, 0.03 mass% or more, 0.032 mass% or more, 0.034 mass% or more, 0.035 mass% or more, 0.04 mass% or more, 0.05 mass% or more, 0.08 mass% or more, 0.1 mass% or more, 0.13 mass% or more, 0.15 mass% or more, 0.18 mass% or more, or 0.2 mass% or more. The content of 4-pyrone compounds is 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.18% by mass or less, 0.15 It may be 0.13% by mass or less, 0.1% by mass or less, 0.08% by mass or less, 0.05% by mass or less, 0.04% by mass or less, 0.035% by mass or less, or 0.034% by mass or less. From these viewpoints, the content of the 4-pyrone compound may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.3 mass%, 0.02 to 0.1 mass%, or 0.02 to 0.05 mass%.

[0037] The mass ratio A of the content of the 4-pyrone compound to the content of the abrasive grains (4-pyrone compound / abrasive grains) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer. The mass ratio A may be 0.01 or more, 0.03 or more, 0.5 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.13 or more, 0.15 or more, 0.18 or more, or 0.2 or more. The mass ratio A may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.18 or less, 0.15 or less, 0.13 or less, 0.12 or less, or 0.1 or less. From these viewpoints, the mass ratio A may be 0.01 to 1, 0.01 to 0.3, 0.01 to 0.15, 0.1 to 1, 0.1 to 0.3, 0.1 to 0.15, 0.12 to 1, 0.12 to 0.3, or 0.12 to 0.15.

[0038] [Component (A2): Picolinic acid] The additive for the polishing liquid according to the second embodiment contains picolinic acid as the component (A2). It is presumed that the use of the component (A2) enhances the interaction between the polishing liquid and silicon oxide, which tends to increase the removal rate.

[0039] The content of picolinic acid may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. The content of picolinic acid may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, 0.1 mass% or more, 0.12 mass% or more, 0.15 mass% or more, 0.18 mass% or more, or 0.2 mass% or more. The content of picolinic acid may be 5 mass% or less, 3 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.5 mass% or less, 0.4 mass% or less, 0.3 mass% or less, or 0.2 mass% or less. From these viewpoints, the content of picolinic acid may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.5 mass%, 0.001 to 0.3 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.5 mass%, 0.01 to 0.3 mass%, 0.1 to 5 mass%, 0.1 to 1 mass%, 0.1 to 0.5 mass%, or 0.1 to 0.3 mass%.

[0040] The mass ratio A2 of the content of picolinic acid to the content of abrasive grains (picolinic acid / abrasive grains) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer. The mass ratio A2 may be 0.01 or more, 0.03 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.15 or more, 0.18 or more, or 0.2 or more. The mass ratio A2 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.25 or less, or 0.2 or less. From these viewpoints, the mass ratio A2 may be 0.01 to 1, 0.01 to 0.5, 0.01 to 0.3, 0.01 to 0.2, 0.05 to 1, 0.05 to 0.5, 0.05 to 0.3, 0.05 to 0.2, 0.1 to 1, 0.1 to 0.5, 0.1 to 0.3, or 0.1 to 0.2.

[0041] [(B) Saturated monocarboxylic acid] The additive of the polishing liquid according to this embodiment contains a saturated monocarboxylic acid as component (B). Component (B) can be used for the purpose of improving the dispersibility of abrasive grains, etc. Component (B) can also contribute to the adjustment of the polishing rate ratio of silicon oxide on the convex portion of the pattern wafer to silicon oxide on the blanket wafer, the polishing rate of silicon nitride that can be used as a stopper material, etc.

[0042] Examples of the saturated monocarboxylic acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hydroangelic acid, caproic acid, 2-methylpentanoic acid, 4-methylpentanoic acid, 2,3-dimethylbutanoic acid, 2-ethylbutanoic acid, 2,2-dimethylbutanoic acid, and 3,3-dimethylbutanoic acid. The number of carbon atoms in the saturated monocarboxylic acid may be 1 to 6, 2 to 6, 1 to 4, 2 to 4, 1 to 3, or 2 to 3, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer, and from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer, and from the viewpoint of effectively obtaining an effect of suppressing the polishing rate of silicon nitride, the saturated monocarboxylic acid may contain an aliphatic carboxylic acid, may contain at least one selected from the group consisting of acetic acid and propionic acid, and may contain propionic acid.

[0043] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer relative to silicon oxide in the blanket wafer and effectively obtaining an effect of suppressing the polishing rate of silicon nitride, the content of the saturated monocarboxylic acid may be within the following range based on the total mass of the polishing liquid: The content of the saturated monocarboxylic acid may be 0.0001 mass% or more, 0.0003 mass% or more, 0.0005 mass% or more, 0.001 mass% or more, 0.002 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.02 mass% or more, 0.03 mass% or more, 0.04 mass% or more, 0.045 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.2 mass% or more, 0.3 mass% or more, or 0.4 mass% or more. The content of saturated monocarboxylic acid is 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, It may be 0.05% by mass or less, 0.045% by mass or less, 0.04% by mass or less, 0.03% by mass or less, 0.02% by mass or less, 0.01% by mass or less, or 0.005% by mass or less. From these viewpoints, the content of the saturated monocarboxylic acid may be 0.0001 to 5 mass%, 0.0001 to 1 mass%, 0.0001 to 0.1 mass%, 0.0001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.03 to 5 mass%, 0.03 to 1 mass%, 0.03 to 0.1 mass%, or 0.03 to 0.05 mass%.

[0044] The mass ratio B1 of the saturated monocarboxylic acid content to the abrasive content (saturated monocarboxylic acid / abrasive) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. The mass ratio B1 may be 0.001 or more, 0.002 or more, 0.005 or more, 0.01 or more, 0.05 or more, 0.1 or more, 0.15 or more, 0.2 or more, 0.5 or more, 1 or more, more than 1, or 1.5 or more. The mass ratio B1 may be 10 or less, 5 or less, 2 or less, 1.5 or less, 1 or less, less than 1, 0.5 or less, 0.2 or less, 0.15 or less, 0.1 or less, 0.05 or less, 0.01 or less, 0.005 or less, or 0.002 or less. From these viewpoints, the mass ratio B1 may be 0.001 to 10, 0.001 to 2, 0.001 to 0.5, 0.05 to 10, 0.05 to 2, 0.05 to 0.5, 0.1 to 10, 0.1 to 2, or 0.1 to 0.5.

[0045] In the polishing liquid according to the first embodiment, the mass ratio B2 of the content of the saturated monocarboxylic acid relative to the content of the component (A1) (saturated monocarboxylic acid / component (A1)) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer. The mass ratio B2 may be 0.001 or more, 0.005 or more, 0.01 or more, 0.02 or more, 0.05 or more, 0.1 or more, 0.5 or more, 0.8 or more, 1 or more, 1.5 or more, 2 or more, 5 or more, or 10 or more. The mass ratio B2 may be 20 or less, 10 or less, 5 or less, 2 or less, 1.5 or less, 1 or less, 0.8 or less, 0.5 or less, 0.1 or less, 0.05 or less, 0.02 or less, 0.015 or less, or 0.1 or less. From these viewpoints, the mass ratio B2 may be 0.001-20, 0.001-5, 0.001-2, 0.05-20, 0.05-5, 0.05-2, 1-20, 1-5, or 1-2.

[0046] In the polishing liquid according to the second embodiment, the mass ratio B3 of the content of the saturated monocarboxylic acid relative to the content of the component (A2) (saturated monocarboxylic acid / component (A2)) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer. The mass ratio B3 may be 0.001 or more, 0.003 or more, 0.005 or more, 0.008 or more, or 0.01 or more. The mass ratio B3 may be 1 or less, less than 1, 0.5 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.03 or less, 0.02 or less, or 0.01 or less. From these viewpoints, the mass ratio B3 may be 0.001 to 1, 0.001 to 0.5, 0.001 to 0.1, 0.005 to 1, 0.005 to 0.5, 0.005 to 0.1, 0.01 to 1, 0.01 to 0.5, or 0.01 to 0.1.

[0047] [Component (C): Nitrogen-containing hydroxyalkyl compound] The additive of the polishing liquid according to this embodiment may contain, as component (C), a compound having two or more nitrogen atoms bonded to a hydroxyalkyl group (nitrogen-containing hydroxyalkyl compound; excluding compounds corresponding to component (A1)). By using component (C), the interaction between the polishing liquid and the silicon oxide of the convex portions in the concave-convex pattern is increased, making it easier to obtain a high polishing rate for the silicon oxide of the convex portions and to suppress the polishing rate for silicon nitride that can be used as a stopper material. In component (C), a hydroxyalkyl group is directly bonded to a nitrogen atom, and a hydroxy group is directly bonded to the alkyl group directly bonded to the nitrogen atom. In component (C), an alkyl group having no substituent other than a hydroxy group can be used as the hydroxyalkyl group bonded to the nitrogen atom.

[0048] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, component (C) may include a compound having a nitrogen atom to which two hydroxyalkyl groups are bonded, or may include a compound having two or more nitrogen atoms to which two hydroxyalkyl groups are bonded.

[0049] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer and easily suppressing the polishing rate of silicon nitride, the number of nitrogen atoms in one molecule of component (C) may be 2 to 5, 2 to 4, or 2 to 3. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer and easily suppressing the polishing rate of silicon nitride, the number of hydroxyl groups in one molecule of component (C) may be 2 to 6, 2 to 5, 2 to 4, 3 to 6, 3 to 5, 3 to 4, 4 to 6, or 4 to 5.

[0050] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in a blanket wafer and easily suppressing the polishing rate of silicon nitride, component (C) may have, as a hydroxyalkyl group bonded to a nitrogen atom, a hydroxyalkyl group having 1 to 4, 2 to 4, 3 to 4, 1 to 3, 2 to 3 or 1 to 2 carbon atoms. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in a blanket wafer and easily suppressing the polishing rate of silicon nitride, component (C) may have, as a hydroxyalkyl group bonded to a nitrogen atom, a hydroxyalkyl group having 1 to 3 or 1 to 2 hydroxy groups.

[0051] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the component (C) may have an alkylene group between two nitrogen atoms bonded to hydroxyalkyl groups, and the number of carbon atoms in the alkylene group may be 1 to 4, 2 to 4, 1 to 3, 2 to 3, or 1 to 2.

[0052] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the component (C) may contain a compound represented by the following general formula (I):

[0053] [ka] [In the formula, n is an integer of 1 or more, and R 11 , R 12 , R 13 and R 14 each independently represents a hydrogen atom or an organic group; R 11 and R 12 one or both of R 13 and R 14 One or both of the groups are hydroxyalkyl groups.

[0054] n may be in the range described above as the number of carbon atoms in the alkylene group between the two nitrogen atoms to which the hydroxyalkyl groups are bonded. The organic group may be a substituted or unsubstituted alkyl group, a hydroxyalkyl group, or a group having a nitrogen atom to which a hydroxyalkyl group is bonded. Examples of the substituent of the alkyl group include a hydroxy group, a carboxy group, an amino group, a sulfo group, and a nitro group. R 11 , R 12 , R 13 or R 14 When is a hydroxyalkyl group, the number of carbon atoms in the hydroxyalkyl group may be within the range described above for the number of carbon atoms in a hydroxyalkyl group bonded to a nitrogen atom.

[0055] Examples of component (C) include ethylenedinitrilotetraethanol (THEED: 2,2',2'',2'''-ethylenedinitrilotetraethanol (also known as N,N,N',N'-Tetrakis(2-hydroxyethyl)ethylenediamine), etc.), ethylenedinitrilotetrapropanol (EDTP: 1,1',1'',1'''-ethylenedinitrilotetra-2-propanol (also known as N,N,N',N'-Tetrakis(2-hydroxypropyl)ethylenediamine), etc.), and N,N,N',N'',N''-Pentakis(2-hydroxypropyl)diethylenetriamine. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer and easily suppressing the polishing rate of silicon nitride, the component (C) may contain at least one selected from the group consisting of ethylene dinitrilotetraethanol and ethylene dinitrilotetrapropanol, may contain ethylene dinitrilotetraethanol, or may contain ethylene dinitrilotetrapropanol. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer and easily suppressing the polishing rate of silicon nitride, the component (C) may contain a compound that does not have a carboxy group.

[0056] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the molecular weight of the component (C) may be within the following range: The molecular weight of the component (C) may be 50 or more, 60 or more, 70 or more, 80 or more, 85 or more, 90 or more, 100 or more, 110 or more, 120 or more, 123 or more, 125 or more, 130 or more, 140 or more, 148 or more, 150 or more, 160 or more, 170 or more, 180 or more, 200 or more, 210 or more, 230 or more, 250 or more, more than 250, or 280 or more. The molecular weight of the (C) component may be 1000 or less, less than 1000, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 350 or less, 300 or less, 280 or less, 250 or less, less than 250, or 240 or less. From these viewpoints, the molecular weight of the (C) component may be 50 to 1000, 50 to 500, 50 to 300, 50 to 250, 200 to 1000, 200 to 500, 200 to 300, 200 to 250, 250 to 1000, 250 to 500, or 250 to 300.

[0057] In the polishing liquid according to the first embodiment, the content C1 of the component (C), the content of ethylene dinitrilotetraethanol, or the content of ethylene dinitrilotetrapropanol may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride. The content C1 may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.015 mass% or more, 0.02 mass% or more, 0.025 mass% or more, 0.03 mass% or more, 0.035 mass% or more, 0.04 mass% or more, 0.045 mass% or more, 0.05 mass% or more, 0.06 mass% or more, 0.08 mass% or more, 0.1 mass% or more, or 0.11 mass% or more. Content C1 is 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.11% by mass or less, 0.1% by mass or less, 0.08 It may be 0.06% by mass or less, 0.05% by mass or less, 0.045% by mass or less, 0.04% by mass or less, 0.035% by mass or less, 0.03% by mass or less, 0.025% by mass or less, or 0.02% by mass or less. From these viewpoints, the content C1 may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.1 mass%, or 0.02 to 0.05 mass%.

[0058] In the polishing liquid according to the second embodiment, the content C2 of the component (C), the content of ethylenedinitrilotetraethanol, or the content of ethylenedinitrilotetrapropanol may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride. The content C2 may be 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.015% by mass or more, 0.02% by mass or more, 0.025% by mass or more, 0.03% by mass or more, 0.035% by mass or more, 0.04% by mass or more, 0.045% by mass or more, 0.05% by mass or more, 0.06% by mass or more, 0.08% by mass or more, 0.1% by mass or more, 0.12% by mass or more, 0.13% by mass or more, 0.15% by mass or more, 0.2% by mass or more, or 0.22% by mass or more. Content C2 is 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.22% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.13% by mass or less, 0.12% by mass or less, 0.1 It may be 0.08% by mass or less, 0.06% by mass or less, 0.05% by mass or less, 0.045% by mass or less, 0.04% by mass or less, 0.035% by mass or less, 0.03% by mass or less, 0.025% by mass or less, or 0.02% by mass or less. From these viewpoints, the content C2 may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.3 mass%, or 0.02 to 0.05 mass%.

[0059] In the polishing liquid according to the first embodiment, the mass ratio C11 of the content of the component (C) relative to the content of the abrasive grains (component (C) / abrasive grains), the mass ratio of the content of the ethylene dinitrilotetraethanol relative to the content of the abrasive grains (ethylene dinitrilotetraethanol / abrasive grains), or the mass ratio of the content of the ethylene dinitrilotetrapropanol relative to the content of the abrasive grains (ethylene dinitrilotetrapropanol / abrasive grains) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride. The mass ratio C11 may be 0.001 or more, 0.005 or more, 0.01 or more, 0.02 or more, 0.03 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.15 or more, 0.18 or more, or 0.2 or more. The mass ratio C11 may be 10 or less, 5 or less, 2 or less, 1 or less, less than 1, 0.5 or less, 0.3 or less, 0.2 or less, 0.18 or less, 0.15 or less, 0.12 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.03 or less, or 0.02 or less. From these viewpoints, the mass ratio C11 may be 0.001 to 10, 0.001 to 1, 0.001 to 0.3, 0.001 to 0.1, 0.01 to 10, 0.01 to 1, 0.01 to 0.3, 0.01 to 0.1, 0.02 to 10, 0.02 to 1, 0.02 to 0.3, or 0.02 to 0.1.

[0060] In the polishing liquid according to the second embodiment, the mass ratio C21 of the content of the component (C) relative to the content of the abrasive grains (component (C) / abrasive grains), the mass ratio of the content of ethylene dinitrilotetraethanol relative to the content of the abrasive grains (ethylene dinitrilotetraethanol / abrasive grains), or the mass ratio of the content of ethylene dinitrilotetrapropanol relative to the content of the abrasive grains (ethylene dinitrilotetrapropanol / abrasive grains) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer relative to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride. The mass ratio C21 may be 0.001 or more, 0.005 or more, 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.08 or more, 0.1 or more, 0.13 or more, 0.15 or more, 0.2 or more, or 0.22 or more. The mass ratio C21 may be 10 or less, 5 or less, 2 or less, 1 or less, less than 1, 0.5 or less, 0.3 or less, 0.25 or less, 0.22 or less, 0.2 or less, 0.15 or less, 0.13 or less, 0.1 or less, 0.08 or less, 0.06 or less, 0.05 or less, 0.04 or less, 0.03 or less, or 0.02 or less. From these viewpoints, the mass ratio C21 may be 0.001 to 10, 0.001 to 1, 0.001 to 0.3, 0.001 to 0.2, 0.01 to 10, 0.01 to 1, 0.01 to 0.3, 0.01 to 0.2, 0.03 to 10, 0.03 to 1, 0.03 to 0.3, or 0.03 to 0.2.

[0061] In the polishing liquid according to the first embodiment, the mass ratio C12 of the content of the component (C) to the content of the component (A1) (component (C) / component (A1)), the mass ratio of the content of ethylenedinitrilotetraethanol to the content of the component (A1) (ethylenedinitrilotetraethanol / component (A1)), or the mass ratio of the content of ethylenedinitrilotetrapropanol to the content of the component (A1) (ethylenedinitrilotetrapropanol / component (A1)) may be in the following range from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer and easily suppressing the polishing rate of silicon nitride. The mass ratio C12 may be 0.01 or more, 0.05 or more, 0.1 or more, 0.15 or more, 0.2 or more, 0.3 or more, 0.5 or more, 0.6 or more, 0.8 or more, 0.85 or more, 0.9 or more, 1 or more, more than 1, 1.1 or more, 1.2 or more, 1.4 or more, or 1.5 or more. The mass ratio C12 may be 10 or less, 8 or less, 5 or less, 2 or less, 1.5 or less, 1.4 or less, 1.2 or less, 1.1 or less, 1 or less, less than 1, 0.9 or less, 0.85 or less, 0.8 or less, 0.6 or less, 0.5 or less, 0.3 or less, 0.2 or less, 0.15 or less, or 0.1 or less. From these viewpoints, the mass ratio C12 may be 0.01 to 10, 0.01 to 2, 0.01 to 1, 0.01 to 0.5, 0.05 to 10, 0.05 to 2, 0.05 to 1, 0.05 to 0.5, 0.15 to 10, 0.15 to 2, 0.15 to 1, or 0.15 to 0.5.

[0062] In the polishing liquid according to the second embodiment, the mass ratio C22 of the content of the component (C) to the content of the component (A2) (component (C) / component (A2)), the mass ratio of the content of ethylenedinitrilotetraethanol to the content of the component (A2) (ethylenedinitrilotetraethanol / component (A2)), or the mass ratio of the content of ethylenedinitrilotetrapropanol to the content of the component (A2) (ethylenedinitrilotetrapropanol / component (A2)) may be in the following range from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer and from the viewpoint of easily suppressing the polishing rate of silicon nitride. The mass ratio C22 may be 0.01 or more, 0.05 or more, 0.1 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.5 or more, 0.6 or more, 0.65 or more, 0.7 or more, 0.8 or more, 1 or more, more than 1, or 1.1 or more. The mass ratio C22 may be 10 or less, 8 or less, 5 or less, 2 or less, 1.5 or less, 1.2 or less, 1.1 or less, 1 or less, less than 1, 0.8 or less, 0.7 or less, 0.65 or less, 0.6 or less, 0.5 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.1 or less, or 0.08 or less. From these viewpoints, the mass ratio C22 may be 0.01 to 10, 0.01 to 2, 0.01 to 1, 0.01 to 0.8, 0.1 to 10, 0.1 to 2, 0.1 to 1, 0.1 to 0.8, 0.2 to 10, 0.2 to 2, 0.2 to 1, or 0.2 to 0.8.

[0063] [Component (D): a compound whose 1 mM aqueous solution has a pH of 3.7 or higher] The additive of the polishing liquid according to this embodiment may contain, as component (D), a compound having a pH of 3.7 or more in an aqueous solution of 1 mM (millimolar concentration) (excluding compounds corresponding to component (A1)). As component (D), a compound corresponding to component (E) described below can be used. By using component (D), it is easy to obtain a high polishing rate for silicon oxide of the convex parts by increasing the interaction between the polishing liquid and the silicon oxide of the convex parts in the concave-convex pattern. Since compounds that can be acid-dissociated in multiple stages have multiple pKa, it is complicated to select an effective compound based on the pKa, but such complicatedness can be avoided by selecting a compound based on the pH that the compound gives in an aqueous solution of 1 mM.

[0064] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer, the pH of a 1 mM aqueous solution of the component (D) may be in the following range: The pH of a 1 mM aqueous solution of the component (D) may be 3.7 or more, 3.8 or more, 4.0 or more, 4.5 or more, 5.0 or more, more than 5.0, 5.4 or more, 5.5 or more, 5.6 or more, 5.8 or more, 5.9 or more, 6.0 or more, 6.2 or more, 6.5 or more, 6.7 or more, 7.0 or more, 7.2 or more, 7.5 or more, 8.0 or more, 8.5 or more, 8.6 or more, 9.0 or more, 9.2 or more, 9.4 or more, 9.5 or more, 9.8 or more, 10.0 or more, or 10.2 or more. The pH of a 1 mM aqueous solution of component (D) may be 14.0 or less, 13.0 or less, 12.0 or less, 11.0 or less, 10.5 or less, 10.2 or less, 10.0 or less, 9.8 or less, 9.5 or less, 9.4 or less, 9.2 or less, 9.0 or less, 8.6 or less, 8.5 or less, 8.0 or less, 7.5 or less, 7.2 or less, 7.0 or less, 6.7 or less, 6.5 or less, 6.2 or less, 6.0 or less, 5.9 or less, 5.8 or less, 5.6 or less, 5.5 or less, or 5.4 or less. From these viewpoints, the pH of a 1 mM aqueous solution of component (D) may be 3.7 to 14.0, 3.7 to 12.0, 3.7 to 11.0, 5.0 to 14.0, 5.0 to 12.0, 5.0 to 11.0, 8.0 to 14.0, 8.0 to 12.0, 8.0 to 11.0, 10.0 to 14.0, 10.0 to 12.0, or 10.0 to 11.0. The 1 mM aqueous solution of component (D) is a mixture consisting of component (D) and water.

[0065] Examples of the component (D) include amino acids, pyridine compounds (compounds having a pyridine ring), imidazole compounds (compounds having an imidazole ring), pyrazole compounds (compounds having a pyrazole ring), triazole compounds (compounds having a triazole ring), compounds containing an amino group and a benzene ring, and triethanolamines (2,2',2''-nitrilotriethanol, etc.).

[0066] Examples of the amino acid include histidine (L-histidine, etc.), lysine, arginine, glutamine (L-glutamine, etc.), glutamic acid (L-glutamic acid, etc.), proline (L-proline, etc.), bicine, cysteine ​​(L-cysteine, etc.), alanine (L-alanine, etc.), serine (L-serine, etc.), aminoacetic acid (glycine), tyrosine (L-tyrosine, etc.), and phenylalanine. The amino acid may be a basic amino acid or an aromatic amino acid. Examples of the pyridine compound include pyridine, hydroxypyridine (3-hydroxypyridine, 4-hydroxypyridine, etc.), pyridine carboxylic acid (nicotinic acid, picolinic acid, etc.), methylpyridine (2-methylpyridine, etc.), acetylpyridine (2-acetylpyridine, etc.), pyridine ethanol (2-pyridine ethanol, etc.), and aminopyridine (3-aminopyridine, etc.). Examples of imidazole compounds include imidazole, methylimidazole (e.g., 2-methylimidazole), and dimethylimidazole (e.g., 1,2-dimethylimidazole). Examples of pyrazole compounds include pyrazole and methylpyrazole. Examples of triazole compounds include triazole (e.g., 1,2,4-triazole), and aminotriazole (e.g., 3-amino-1,2,4-triazole). Examples of compounds containing an amino group and a benzene ring include aminobenzene (aniline), anthranilic acid, and the like.

[0067] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer, the component (D) may contain at least one selected from the group consisting of amino acids, pyridine compounds, imidazole compounds, pyrazole compounds, triazole compounds, compounds containing an amino group and a benzene ring, and triethanolamine, and may contain at least one selected from the group consisting of histidine, aminoacetic acid, hydroxypyridine, pyridineethanol, imidazole, methylimidazole, and triethanolamine. The additive of the polishing liquid according to this embodiment may be an embodiment containing hydroxypyridine, or an embodiment containing triethanolamine. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer, the component (D) may contain a compound that does not fall under the category of aromatic polyoxyalkylene compounds (compounds having an aromatic ring and a polyoxyalkylene chain), may contain a compound that does not have an aromatic ring, or may contain a compound that does not have a polyoxyalkylene chain.

[0068] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, the molecular weight of component (D) may be within the following range: The molecular weight of component (D) may be 50 or more, 60 or more, 70 or more, 80 or more, 85 or more, 90 or more, 100 or more, 110 or more, 120 or more, 123 or more, 125 or more, 130 or more, 140 or more, 148 or more, or 150 or more. The molecular weight of component (D) may be 1000 or less, less than 1000, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 350 or less, 300 or less, 280 or less, 250 or less, less than 250, 240 or less, 230 or less, 210 or less, 200 or less, 180 or less, 170 or less, 160 or less, 150 or less, 148 or less, 140 or less, 130 or less, 125 or less, 123 or less, 120 or less, 110 or less, 100 or less, 90 or less, 85 or less, 80 or less, or 70 or less. From these viewpoints, the molecular weight of the (D) component may be 50-1000, 50-500, 50-200, 50-100, 60-1000, 60-500, 60-200, 60-100, 80-1000, 80-500, 80-200, or 80-100.

[0069] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer relative to silicon oxide in the blanket wafer, the content of the component (D) may be within the following range based on the total mass of the polishing liquid: The content of the component (D) may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.015 mass% or more, 0.02 mass% or more, 0.025 mass% or more, 0.03 mass% or more, 0.035 mass% or more, 0.04 mass% or more, 0.05 mass% or more, 0.06 mass% or more, 0.08 mass% or more, 0.1 mass% or more, 0.15 mass% or more, 0.2 mass% or more, or 0.3 mass% or more. The content of component (D) is 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.1% by mass or less, 0. It may be 0.08% by mass or less, 0.06% by mass or less, 0.05% by mass or less, 0.04% by mass or less, 0.035% by mass or less, 0.03% by mass or less, 0.025% by mass or less, or 0.02% by mass or less. From these viewpoints, the content of component (D) may be 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.1 mass%, 0.02 to 0.05 mass%, 0.03 to 5 mass%, 0.03 to 1 mass%, 0.03 to 0.1 mass%, or 0.03 to 0.05 mass%. The content of component (D) includes the contents of compounds corresponding to components (D) and (E) (hereinafter the same).

[0070] The mass ratio D1 of the content of the component (D) to the content of the abrasive grains (component (D) / abrasive grains) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. The mass ratio D1 may be 0.001 or more, 0.005 or more, 0.01 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.11 or more, 0.12 or more, 0.15 or more, 0.16 or more, 0.2 or more, 0.3 or more, 0.5 or more, 1 or more, or more than 1. The mass ratio D1 may be 10 or less, 5 or less, 2 or less, 1 or less, less than 1, 0.5 or less, 0.3 or less, 0.2 or less, 0.16 or less, 0.15 or less, 0.12 or less, 0.11 or less, 0.1 or less, or 0.08 or less. From these viewpoints, the mass ratio D1 may be 0.001 to 10, 0.001 to 1, 0.001 to 0.2, 0.01 to 10, 0.01 to 1, 0.01 to 0.2, 0.1 to 10, 0.1 to 1, or 0.1 to 0.2.

[0071] The mass ratio D2 of the content of the component (D) to the content of the component (A1) (component (D) / component (A1)) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. The mass ratio D2 may be 0.01 or more, 0.05 or more, 0.1 or more, 0.3 or more, 0.5 or more, 0.6 or more, 0.8 or more, 0.85 or more, 0.9 or more, 1 or more, more than 1, 1.1 or more, 1.2 or more, 1.4 or more, 1.5 or more, 2 or more, 5 or more, or 8 or more. The mass ratio D2 may be 10 or less, 8 or less, 5 or less, 2 or less, 1.5 or less, 1.4 or less, 1.2 or less, 1.1 or less, 1 or less, less than 1, 0.9 or less, 0.85 or less, 0.8 or less, or 0.6 or less. From these viewpoints, the mass ratio D2 may be 0.01 to 10, 0.01 to 2, 0.01 to 1.2, 0.1 to 10, 0.1 to 2, 0.1 to 1.2, 0.8 to 10, 0.8 to 2, or 0.8 to 1.2.

[0072] [Component (E): a cyclic compound having at least one functional group selected from the group consisting of a carboxyl group, a carboxylate group, an amino group, and a hydroxyl group] The additive of the polishing liquid according to this embodiment may contain a component (E) (excluding compounds corresponding to the component (A1) or (A2)). By using the component (E), the interaction between the polishing liquid and the silicon oxide of the convex portions in the concave-convex pattern is increased, making it easier to obtain a high polishing rate for the silicon oxide of the convex portions. The component (E) may have at least one selected from the group consisting of a carboxy group and a carboxylate group, from the viewpoint of making it easier to obtain a high polishing rate ratio of the silicon oxide of the convex portions of the patterned wafer to the silicon oxide of the blanket wafer. As the component (E), a compound that also corresponds to the component (D) can be used. As the salt of the carboxylate group, an alkali metal salt such as a sodium salt or a potassium salt can be mentioned.

[0073] The component (E) may have at least one ring selected from the group consisting of an aromatic ring, a heterocyclic ring (excluding aromatic rings), and an alicyclic ring. The aromatic ring may be a heteroaromatic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a pyridine ring, and a quinoline ring. The component (E) may have an aromatic ring other than a benzene ring.

[0074] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer, the component (E) may contain an aromatic compound (a compound having an aromatic ring), and may contain at least one selected from the group consisting of aromatic carboxylic acids (aromatic compounds having a carboxy group) and aromatic carboxylates (aromatic compounds having a carboxylate group). The component (E) may contain at least one selected from the group consisting of aromatic aminocarboxylic acids (aminobenzoic acid, aminobenzenesulfonic acid, etc.), aromatic oxycarboxylic acids (aromatic hydroxycarboxylic acids, excluding aromatic aminocarboxylic acids), aromatic carboxylic acids not having amino groups or hydroxy groups (quinoline carboxylic acid, pyridine carboxylic acid, etc.), and salts thereof, and may contain at least one selected from the group consisting of aromatic aminocarboxylic acids, quinoline carboxylic acids, pyridine carboxylic acids, and salts thereof.

[0075] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, the component (E) may contain at least one member selected from the group consisting of benzoic acid, benzoic acid derivatives, hydroxyphenylacetic acid, alkylsalicylic acid, phthalic acid, phthalic acid derivatives, quinoline derivatives, pyridine derivatives, aminobenzenesulfonic acid, salts thereof, and salicylaldoxime.

[0076] The benzoic acid derivative may contain at least one selected from the group consisting of hydroxybenzoic acid and aminobenzoic acid, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer. Examples of hydroxybenzoic acid include salicylic acid (2-hydroxybenzoic acid) and 4-hydroxybenzoic acid. Examples of aminobenzoic acid include anthranilic acid. Examples of hydroxyphenylacetic acid include mandelic acid. Examples of alkylsalicylic acid include methylsalicylic acid (e.g., 3-methylsalicylic acid). The phthalic acid derivative may contain at least one selected from the group consisting of alkylphthalic acid, aminophthalic acid, and sulfophthalic acid. Examples of alkylphthalic acid include methylphthalic acid (e.g., 4-methylphthalic acid). Examples of aminophthalic acid include 4-aminophthalic acid. Examples of sulfophthalic acid include 4-sulfophthalic acid. The quinoline derivative may contain quinoline carboxylic acid from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. Examples of quinoline carboxylic acid include quinaldic acid. The pyridine derivative may contain pyridine carboxylic acid from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer. Examples of pyridine carboxylic acid include nicotinic acid. Examples of aminobenzenesulfonic acid include orthanilic acid. The component (E) may be in an embodiment containing at least one selected from the group consisting of quinaldic acid and salts thereof, or in an embodiment containing at least one selected from the group consisting of anthranilic acid and salts thereof.

[0077] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, the component (E) may contain at least one member selected from the group consisting of aminobenzoic acid, hydroxyphenylacetic acid, quinoline derivatives, and pyridine derivatives.

[0078] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in the blanket wafer, the molecular weight of the component (E) may be within the following ranges: The molecular weight of the component (E) may be 80 or more, 90 or more, 100 or more, 110 or more, 120 or more, 125 or more, 130 or more, 135 or more, 138 or more, 140 or more, 150 or more, 160 or more, or 170 or more. The molecular weight of the component (E) may be 1000 or less, less than 1000, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 300 or less, 250 or less, 200 or less, 180 or less, 170 or less, 160 or less, 150 or less, 140 or less, 138 or less, 135 or less, 130 or less, or 125 or less. From these viewpoints, the molecular weight of the (E) component may be 80-1000, 80-200, 80-150, 100-1000, 100-200, 100-150, 120-1000, 120-200, 120-150, 130-1000, 130-200, or 130-150.

[0079] From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide in the convex portion of the patterned wafer to silicon oxide in the blanket wafer, the content of the component (E) may be within the following range based on the total mass of the polishing liquid. The content of the component (E) may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.015 mass% or more, 0.02 mass% or more, 0.025 mass% or more, 0.03 mass% or more, 0.035 mass% or more, 0.04 mass% or more, 0.05 mass% or more, 0.06 mass% or more, or 0.08 mass% or more. The content of the component (E) may be 5 mass% or less, 3 mass% or less, 1 mass% or less, 0.5 mass% or less, 0.3 mass% or less, 0.1 mass% or less, 0.08 mass% or less, 0.06 mass% or less, 0.05 mass% or less, or 0.04 mass% or less. From these viewpoints, the content of the component (E) may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.03 to 5 mass%, 0.03 to 1 mass%, 0.03 to 0.1 mass%, or 0.03 to 0.05 mass%. The content of the component (E) includes the contents of the compounds corresponding to the components (D) and (E) (the same applies below).

[0080] The mass ratio E1 of the content of the component (E) relative to the content of the abrasive grains (component (E) / abrasive grains) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer relative to silicon oxide on the blanket wafer. The mass ratio E1 may be 0.01 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.15 or more, or 0.16 or more. The mass ratio E1 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.16 or less, 0.15 or less, 0.12 or less, 0.1 or less, or 0.08 or less. From these viewpoints, the mass ratio E1 may be 0.01 to 1, 0.01 to 0.5, 0.01 to 0.2, 0.01 to 0.1, 0.05 to 1, 0.05 to 0.5, 0.05 to 0.2, 0.05 to 0.1, 0.1 to 1, 0.1 to 0.5, or 0.1 to 0.2.

[0081] The mass ratio E2 of the content of the component (E) to the content of the component (A1) (component (E) / component (A1)) may be in the following range, from the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer. The mass ratio E2 may be 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.8 or more, or 1 or more. The mass ratio E2 may be 10 or less, 5 or less, 3 or less, 2 or less, 1.5 or less, 1.2 or less, 1 or less, 0.8 or less, or 0.6 or less. From these viewpoints, the mass ratio E2 may be 0.1 to 10, 0.1 to 3, 0.1 to 2, 0.1 to 1, 0.3 to 10, 0.3 to 3, 0.3 to 2, 0.3 to 1, 1 to 10, 1 to 3, or 1 to 2.

[0082] [Other additives] The additive of the polishing liquid according to this embodiment may further contain other components (components other than those mentioned above) according to the desired properties. Such components include nonionic polymers, cationic compounds, pH adjusters described below, polar solvents such as ethanol and acetone, and cyclic monocarboxylic acids.

[0083] The polishing liquid according to this embodiment may contain a compound a having a molecular weight of 100,000 or less and having four or more hydroxyl groups, or may not contain compound a. The content of compound a may be 0.01 mass% or less, less than 0.01 mass%, 0.001 mass% or less, 0.0001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid. The polishing liquid according to this embodiment may contain a compound b having four or more amino groups, or may not contain compound b. The content of compound b may be 0.001 mass% or less, less than 0.001 mass%, 0.0001 mass% or less, 0.00001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid. The mass ratio of the content of compound a to the content of compound b (compound a / compound b) may be 0.10 or less, or less than 0.10.

[0084] (water) The water is not particularly limited, but may include at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0085] (pH) The pH of the polishing liquid according to this embodiment exceeds 4.0 from the viewpoint of easily obtaining the added effect of the components contained in the polishing liquid. The pH may be 12.0 or less, 11.0 or less, 10.5 or less, less than 10.5, 10.0 or less, less than 10.0, 9.5 or less, 9.0 or less, less than 9.0, 8.5 or less, 8.0 or less, less than 8.0, 7.5 or less, 7.0 or less, less than 7.0, 6.5 or less, 6.0 or less, less than 6.0, 5.5 or less, less than 5.5, 5.0 or less, 4.8 or less, 4.7 or less, 4.6 or less, 4.5 or less, 4.4 or less, 4.3 or less, 4.2 or less, or 4.1 or less, from the viewpoints of easily suppressing aggregation of abrasive grains, easily obtaining a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer to silicon oxide in the blanket wafer, easily suppressing the polishing rate of silicon nitride that can be used as a stopper material, and easily obtaining the effects of adding the additive. From the viewpoint of easily obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, the pH may be 4.1 or more, 4.2 or more, 4.3 or more, 4.4 or more, 4.5 or more, 4.6 or more, 4.7 or more, 4.8 or more, 5.0 or more, 5.5 or more, greater than 5.5, 6.0 or more, greater than 6.0, 6.5 or more, 7.0 or more, or greater than 7.0. From these viewpoints, the pH may be more than 4.0 and not more than 12.0, more than 4.0 and not more than 9.0, more than 4.0 and not more than 8.0, more than 4.0 and not more than 5.5, more than 4.0 and not more than 5.0, 4.3 to 12.0, 4.3 or more and not more than 9.0, 4.3 to 8.0, 4.3 to 5.5, 4.3 to 5.0, 4.5 to 12.0, 4.5 or more and not more than 9.0, 4.5 to 8.0, 4.5 to 5.5, or 4.5 to 5.0. The pH can be measured by the method described in the Examples.

[0086] Since the pH may vary depending on the type of compound used as an additive, a pH adjuster may be used to adjust the pH to the above range. There is no particular limitation on the pH adjuster, and examples thereof include acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; and bases such as sodium hydroxide, ammonia (e.g., ammonia water), potassium hydroxide, and calcium hydroxide. The above-mentioned additives such as saturated monocarboxylic acid and aminoacetic acid may be used to adjust the pH. From the viewpoint of improving productivity, the polishing liquid may be prepared without using a pH adjuster, and this polishing liquid may be directly applied to CMP.

[0087] <How to prepare and use the polishing solution> The polishing liquid according to this embodiment can be classified into (a) a normal type, (b) a concentrated type, and (c) a multiple liquid type (e.g., a two-liquid type, a polishing liquid set for CMP), and the preparation method and method of use differ depending on the type. (a) The normal type is a polishing liquid that can be used as is during polishing without pretreatment such as dilution. (b) The concentrated type is a polishing liquid in which the components are concentrated compared to the normal type (a) in consideration of convenience in storage or transportation. (c) The multiple liquid type is a polishing liquid in which the components are separated into multiple liquids (e.g., a first liquid containing certain components and a second liquid containing other components) during storage or transportation, and these liquids are mixed when used.

[0088] (a) The normal type can be obtained by dissolving or dispersing abrasive grains and additives in water, which is the main dispersion medium. For example, to prepare 1000 g of polishing liquid with 0.5 parts by mass of abrasive grains and 0.1 parts by mass of additives per 100 parts by mass of polishing liquid, the amounts of the abrasive grains and additives are adjusted to 5 g and 1 g, respectively, relative to the total amount of the polishing liquid.

[0089] The preparation of the polishing liquid can be carried out using, for example, a stirrer, a homogenizer, an ultrasonic disperser, a wet ball mill, etc. In addition, a process of micronizing the abrasive grains may be carried out in the process of preparing the polishing liquid so that the average grain size of the abrasive grains falls within a desired range. The micronization process of the abrasive grains can be carried out by a sedimentation classification method or a method using a high-pressure homogenizer. The sedimentation classification method is a method that includes a process of forcibly sedimenting a slurry containing the abrasive grains using a centrifuge and a process of extracting only the supernatant liquid. On the other hand, the method using a high-pressure homogenizer is a method in which the abrasive grains in the dispersion medium are collided with each other at high pressure.

[0090] (b) Concentrated type is diluted with water immediately before use so that the content of the ingredients is the desired content. After dilution, stirring may be performed for any length of time until the liquid characteristics (pH, abrasive grain size, etc.) and polishing characteristics (polishing speed of silicon oxide, polishing selectivity between silicon oxide and silicon nitride, etc.) are similar to those of (a) normal type. With such (b) concentrated type, the volume becomes smaller depending on the degree of concentration, so storage and transportation costs can be reduced.

[0091] The concentration ratio may be 1.5 times or more, 2 times or more, 3 times or more, or 5 times or more. When the concentration ratio is 1.5 times or more, advantages in terms of storage and transportation tend to be obtained more easily than when the concentration ratio is less than 1.5 times. The concentration ratio may be 40 times or less, 20 times or less, or 15 times or less. When the concentration ratio is 40 times or less, aggregation of the abrasive grains tends to be suppressed more easily than when the concentration ratio is more than 40 times.

[0092] The (c) multiple liquid type has an advantage over the (b) concentrated type in that each liquid (first liquid, second liquid, etc.) is appropriately separated to avoid aggregation of abrasive grains. Here, the components contained in each liquid are arbitrary. The (c) multiple liquid type (CMP polishing liquid set) is a polishing liquid set for obtaining a polishing liquid by mixing a first liquid (slurry) and a second liquid (additive liquid). In the (c) multiple liquid type, the components of the CMP polishing liquid are stored separately as a first liquid and a second liquid, the first liquid contains abrasive grains and water, and the second liquid contains at least one type of additive and water. In a first embodiment of the (c) multiple liquid type, the first liquid contains abrasive grains and water, and the second liquid contains at least one type selected from the group consisting of the (A1) component and the (A2) component, the (B) component, and water. (c) In the second embodiment of the multiple liquid type, the first liquid contains abrasive grains, at least one selected from the group consisting of the (A1) component and the (A2) component, and water, and the second liquid contains the (B) component and water. (c) In the third embodiment of the multiple liquid type, the first liquid contains abrasive grains, one of the (A1) component and the (A2) component, the (B) component, and water, and the second liquid contains the other of the (A1) component and the (A2) component, and water. (c) In the fourth embodiment of the multiple liquid type, the first liquid contains abrasive grains, the (B) component, and water, and the second liquid contains at least one selected from the group consisting of the (A1) component and the (A2) component, and water. The first liquid and the second liquid may contain other components that are mixed as necessary. In this case, in order to improve the dispersibility of the abrasive grains in the first liquid, any acid or alkali may be added to the first liquid to adjust the pH.

[0093] (c) A multi-liquid type polishing liquid is useful for a combination of components that, when mixed, tend to have their polishing properties deteriorated in a relatively short time due to agglomeration of abrasive grains, etc. From the viewpoint of reducing storage and transportation costs, at least one of the liquids (first liquid, second liquid, etc.) may be a concentrated type. In this case, when using the polishing liquid, each liquid can be mixed with water. The concentration rate and pH of each liquid are arbitrary, and it is sufficient that the final mixture has the same liquid properties and polishing properties as the (a) normal type polishing liquid.

[0094] <Polishing method> The polishing method according to this embodiment includes a polishing step of polishing a surface to be polished using the polishing liquid according to this embodiment. The polishing liquid used in the polishing step may be a polishing liquid obtained by mixing the first liquid and the second liquid in the above-mentioned polishing liquid set. That is, the polishing method according to this embodiment may include a polishing step of polishing a surface to be polished using a polishing liquid obtained by mixing the first liquid and the second liquid in the above-mentioned polishing liquid set.

[0095] The polishing method according to the present embodiment uses a polishing solution in which the content of each component, pH, etc. are adjusted, and can planarize a substrate having a silicon oxide film on its surface by CMP technology. The polishing method according to the present embodiment is suitable for polishing that requires high speed, high flatness, and low polishing scratches, such as polishing an ILD film, and is suitable for applications in which many ILD films are polished in a short time. According to one aspect of the polishing method according to the present embodiment, it is possible to efficiently obtain the effect of improving the polishing rate of silicon oxide on a blanket wafer and the effect of improving the in-plane uniformity. According to one aspect of the polishing method according to the present embodiment, since the polishing solution according to the present embodiment is used, it is possible to reduce the occurrence of polishing scratches while suppressing the aggregation of abrasive grains and achieving a sufficiently high polishing rate.

[0096] The polishing process may be a process of supplying the polishing liquid according to this embodiment between a substrate and a polishing member (a polishing member, such as a polishing pad), and polishing the substrate with the polishing member. The polishing method according to this embodiment is suitable for polishing a substrate having a silicon oxide film on its surface. Therefore, the surface to be polished may contain silicon oxide, and the polishing process may be a process of supplying the polishing liquid according to this embodiment between the silicon oxide film on a substrate having a silicon oxide film on its surface and the polishing member, and polishing the silicon oxide film with the polishing member.

[0097] The polishing method according to this embodiment may be such that the surface to be polished has a concave-convex pattern composed of convex portions (line portions) and concave portions (space portions), and the convex portions contain silicon oxide. The width of the convex portions in the concave-convex pattern may be 30 μm or less, or 20 μm or less. The width of the convex portions in the concave-convex pattern may be 10 μm or more, or 20 μm or more. The sum of the width of the convex portions and the width of the concave portions in the concave-convex pattern may be 200 μm or less, or 100 μm or less. The sum of the width of the convex portions and the width of the concave portions in the concave-convex pattern may be 80 μm or more, or 100 μm or more.

[0098] The polishing method according to this embodiment is suitable for polishing a substrate having a silicon oxide film on its surface in the process of manufacturing a device. Examples of the device include discrete semiconductors such as diodes, transistors, compound semiconductors, thermistors, varistors, and thyristors; memory elements such as DRAM (dynamic random access memory), SRAM (static random access memory), EPROM (erasable programmable read-only memory), mask ROM (mask read-only memory), EEPROM (electrically erasable programmable read-only memory), and flash memory; logic circuit elements such as microprocessors, DSPs, and ASICs; integrated circuit elements such as compound semiconductors represented by MMICs (monolithic microwave integrated circuits); hybrid integrated circuits (hybrid ICs); light-emitting diodes; and photoelectric conversion elements such as charge-coupled devices.

[0099] According to one aspect of the polishing liquid of the present embodiment, a high polishing rate can be achieved without being largely dependent on the uneven shape of the polished surface. Therefore, the polishing method using the polishing liquid can be applied to substrates for which it is difficult to achieve a high polishing rate using conventional polishing liquids.

[0100] The polishing method according to this embodiment is suitable for planarizing a surface to be polished that has steps (unevenness) on the surface. An example of a substrate having such a surface to be polished is a semiconductor device for logic. The polishing method according to this embodiment is also suitable for polishing a surface that includes a portion in which the concave or convex portions are T-shaped or lattice-shaped when viewed from above. For example, the polishing method according to this embodiment can polish a silicon oxide film provided on the surface of a semiconductor device having memory cells (DRAM, flash memory, etc.) at a high speed. These are cases where it was difficult to achieve a high polishing rate using a conventional method using a polishing liquid for CMP, and this shows that one aspect of the polishing liquid according to this embodiment can achieve a high polishing rate without being largely dependent on the uneven shape of the surface to be polished.

[0101] The substrate is not limited to a substrate having only a silicon oxide film on its surface, but may be a substrate having, on its surface, a silicon nitride film, a polycrystalline silicon film, etc., in addition to a silicon oxide film. The substrate may be a substrate having, on a wiring board having predetermined wiring, an inorganic insulating film such as silicon oxide, glass, silicon nitride, etc.; a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc.

[0102] Hereinafter, as an example of a process including the polishing method according to this embodiment, a process of forming an ILD film (interlayer dielectric film) structure by CMP will be described. Fig. 1 is a schematic cross-sectional view showing the process of polishing an ILD film, and shows the process of forming an ILD film between wirings. Fig. 1(a) is a schematic cross-sectional view showing a substrate before polishing. Fig. 1(b) is a schematic cross-sectional view showing the substrate after polishing.

[0103] 1(a), in a base 100 before polishing, a wiring 20 is formed on a lower substrate (not shown) having a predetermined lower wiring (not shown) via an ILD film 10, and a silicon oxide film 30 is formed so as to cover this wiring 20. Since the silicon oxide film 30 is formed on the ILD film 10 on which the wiring 20 is formed, the portion above the wiring 20 is higher than the other portions, resulting in a step D on the surface of the silicon oxide film 30. The wiring 20 is connected to the lower wiring, etc. by a contact plug 40 formed so as to penetrate the ILD film 10.

[0104] In the process of forming the ILD film structure, in order to eliminate the step D, unnecessary portions that protrude partially on the surface of the silicon oxide film 30 are preferentially removed by CMP. To polish the silicon oxide film 30, the substrate 100 is placed on a polishing member so that the surface of the silicon oxide film 30 and the polishing member come into contact with each other, and the surface of the silicon oxide film 30 is polished by the polishing member. More specifically, the surface to be polished (front surface) of the silicon oxide film 30 is pressed against the polishing member of the polishing table, and the silicon oxide film 30 is polished by moving the surface to be polished and the polishing member relatively while supplying a polishing liquid between them. This eliminates the step D, and finally, as shown in FIG. 1(b), the height of the wiring 20 part on the surface of the silicon oxide film 30 becomes almost the same as the height of the other part, and a substrate 100a having a silicon oxide film 30 (ILD film) with a flat surface is obtained.

[0105] The polishing device used for polishing may be, for example, a device equipped with a holder for holding a substrate, a polishing platen on which a polishing pad is attached, and a means for supplying a polishing liquid onto the polishing pad. Examples of the polishing device include polishing devices manufactured by Ebara Corporation (model numbers: EPO-111, EPO-222, F-REX200, and F-REX300), and polishing devices manufactured by Applied Materials (product names: Mirra3400 and Reflexion). There are no particular limitations on the material constituting the polishing pad, and for example, general nonwoven fabric, polyurethane foam, porous fluororesin, etc. may be used. In addition, the polishing pad may be grooved so that the polishing liquid can be collected.

[0106] There are no particular limitations on the polishing conditions, but the rotation speed of the polishing platen is set to 200 min -1 The pressure (processing load) applied to the substrate may be 100 kPa or less from the viewpoint of easily suppressing polishing scratches on the surface to be polished. During polishing, a polishing liquid may be continuously supplied to the polishing pad by a pump or the like. There is no limit to the amount of supply, but the surface of the polishing pad may be constantly covered with the polishing liquid. After polishing is completed, the substrate may be thoroughly washed in running water, and then the substrate may be dried after removing water droplets adhering to the substrate using a spin dryer or the like.

[0107] By polishing in the manner described above, surface irregularities can be eliminated, and a smooth surface can be obtained over the entire surface of the substrate. Furthermore, by repeating the steps of forming a film and polishing this film a predetermined number of times, a structure having a desired number of layers can be manufactured.

[0108] The substrate (structure) thus obtained can be used as various electronic components. Specific examples of electronic components include semiconductor elements, optical glasses such as photomasks, lenses, and prisms, inorganic conductive films such as ITO, optical integrated circuits, optical switching elements, and optical waveguides made of glass and crystalline materials, end faces of optical fibers, optical single crystals such as scintillators, solid-state laser single crystals, sapphire substrates for blue laser LEDs, semiconductor single crystals such as SiC, GaP, and GaAs, glass substrates for magnetic disks, and magnetic heads.

[0109] <Manufacturing method etc.> The component manufacturing method according to the present embodiment includes a component manufacturing step of obtaining a component using a base (a member to be polished) polished by the polishing method according to the present embodiment. The component according to the present embodiment is a component obtained by the component manufacturing method according to the present embodiment. The component according to the present 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 the present embodiment, in the electronic component manufacturing method according to the present embodiment, an electronic component is obtained using a base polished by the polishing method according to the present embodiment. As one aspect of the component manufacturing method according to the present embodiment, in the semiconductor component manufacturing method according to the present embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a base polished by the polishing method according to the present embodiment. The component manufacturing method according to the present embodiment may include a polishing step of polishing a base by the polishing method according to the present embodiment before the component manufacturing step.

[0110] The component manufacturing method according to the present embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a base (a polished member) polished by the polishing method according to the present 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 the present embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to the present embodiment, the electronic component manufacturing method according to the present embodiment may include a process for singulating a base polished by the polishing method according to the present embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to the present embodiment, the semiconductor component manufacturing method according to the present embodiment may include a process for singulating a base polished by the polishing method according to the present embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0111] The manufacturing method of the component according to the present embodiment may include, as one aspect of the component manufacturing process, a connection process for connecting (e.g., electrically connecting) the base (polished member) polished by the polishing method according to the present embodiment to another connected body. The connected body to be connected to the base polished by the polishing method according to the present embodiment is not particularly limited, and may be the base polished by the polishing method according to the present embodiment, or may be a connected body different from the base polished by the polishing method according to the present embodiment. In the connection process, the base and the connected body may be directly connected (connected in a state where the base and the connected body are in contact with each other), or the base and the connected body may be connected via another member (conductive member, etc.). The connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0112] The connecting step may be a step of connecting the polished surface of the base polished by the polishing method according to the present embodiment to the connected body, or may be a step of connecting the connecting surface of the base polished by the polishing method according to the present embodiment to the connecting surface of the connected body. The connecting surface of the base may be the polished surface polished by the polishing method according to the present embodiment. The connecting step can obtain a connected body including the base and the connected body. In the connecting step, if the connecting surface of the base has a metal part, the connected body may be brought into contact with the metal part. In the connecting step, if the connecting surface of the base has a metal part and the connecting surface of the connected body has a metal part, the metal parts may be brought into contact with each other. The metal part may contain copper.

[0113] The device according to this embodiment (for example, an electronic device such as a semiconductor device) comprises at least one selected from the group consisting of a substrate polished by the polishing method according to this embodiment and a part according to this embodiment. EXAMPLES

[0114] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0115] <Preparation of cerium oxide powder> 40 kg of cerium carbonate hydrate was divided and placed into 10 alumina containers, and each was calcined in air at 830°C for 2 hours to obtain a total of 20 kg of yellowish-white powder. Phase identification of this powder was performed using X-ray diffraction, and it was confirmed that the powder contained polycrystalline cerium oxide. The particle size of the powder obtained by calcination was observed using an SEM and was found to be in the range of 20 to 100 μm. Next, 20 kg of the cerium oxide powder was dry-pulverized using a jet mill to obtain cerium oxide powder. The specific surface area of ​​the cerium oxide powder after milling was 9.4 m 2 The specific surface area was measured by the BET method.

[0116] <Slurry preparation> 15.0 kg of the cerium oxide powder obtained above and 84.5 kg of deionized water were mixed in a container. Next, 0.5 kg of 1M (mol / L, about 6 mass%) acetic acid was added, and the mixture was stirred for 10 minutes to obtain a cerium oxide mixed liquid. This cerium oxide mixed liquid was transferred to another container over 30 minutes. During this time, the cerium oxide mixed liquid was irradiated with ultrasonic waves at an ultrasonic frequency of 400 kHz in the pipe through which the liquid was transferred.

[0117] The above-mentioned cerium oxide mixture, which had been delivered after ultrasonic irradiation, was placed in four 500 mL polyethylene containers, each containing 500 g ± 5 g. The cerium oxide mixture in each container was centrifuged for two minutes under conditions that the centrifugal force applied to the outer periphery was 500 G. After centrifugation, the supernatant fraction of the container was collected to obtain a slurry. The slurry contained approximately 6.0 mass % of cerium oxide particles (abrasive grain A) based on the total mass.

[0118] The above-mentioned cerium oxide mixture, which had been delivered after ultrasonic irradiation, was placed in four 500 mL polyethylene containers, each containing 500 g ± 5 g. The cerium oxide mixture in each container was centrifuged for 5 minutes under conditions that the centrifugal force applied to the outer periphery was 1200 G. After centrifugation, the supernatant fraction of the container was collected to obtain a slurry. The slurry contained approximately 2.0 mass % of cerium oxide particles (abrasive grain B) based on the total mass.

[0119] The slurry was diluted with pure water so that the abrasive grain content became 0.25% by mass on a total mass basis to obtain a sample for particle size measurement. For this sample, the average particle size of the abrasive grains was measured using a laser diffraction / scattering particle size distribution analyzer (manufactured by MicrotracBEL Corp., trade name: Microtrac MT3300EXII). As a result, the average particle size of abrasive grain A was 140 nm, and the average particle size of abrasive grain B was 120 nm.

[0120] <Preparation of CMP Polishing Liquid> By mixing the above slurry, each additive, and deionized water according to the following procedure, a polishing liquid having the composition shown in the following tables (balance: deionized water) was obtained. In the tables, "THEED" means 2,2’,2’’,2’’’-ethylenedinitrilotetraethanol, and "EDTP" means 1,1’,1’’,1’’’-ethylenedinitrilotetra-2-propanol. Abrasive grain A was used in the examples except for Examples 21 and 22, and abrasive grain B was used in Examples 21 and 22. Each polishing liquid contains acetic acid in an amount corresponding to the respective abrasive grain content as the acetic acid mixed during the preparation of the above slurry. Note that the pH of a 1 mM aqueous solution of acetic acid is less than 5.0.

[0121] Specifically, an additive solution was obtained by dissolving each additive in deionized water. Next, the above slurry and the additive solution were mixed in the same amount, and then stirred for 10 minutes to obtain a concentrated storage liquid for the polishing liquid containing 5.0% by mass of abrasive grains on a total mass basis. The storage liquid for the polishing liquid contains 20 times the amount of abrasive grains and additives with respect to the abrasive grain content of 0.25% by mass of the final polishing liquid, and contains 5 times the amount of abrasive grains and additives with respect to the abrasive grain content of 1.00% by mass of the final polishing liquid.

[0122] Then, by diluting the storage liquid for the polishing liquid 20-fold with deionized water, the polishing liquids of Examples 1 to 17, 21 to 22, and Comparative Examples 1 to 2 were obtained. Further, by diluting the storage liquid for the polishing liquid 5-fold with deionized water, the polishing liquids of Examples 18 to 20, 23 to 27, and Comparative Example 3 were obtained. For the polishing liquids of each example, when the abrasive grain content was 0.25% by mass on a total mass basis (for the polishing liquid with an abrasive grain content of 1.00% by mass, when adjusted to an abrasive grain content of 0.25% by mass), the average particle diameter of the abrasive grains was equivalent to the average particle diameter of the abrasive grains in the above-mentioned slurry.

[0123] <Zeta potential measurement> An appropriate amount of the polishing liquid was put into the product named "DelsaNano C" manufactured by Beckman Coulter, Inc., and the measurement was carried out twice at 25°C. The average value of the displayed zeta potential was obtained as the zeta potential. In each of the examples and comparative examples, the zeta potential of the abrasive grains was positive.

[0124] <pH measurement> (pH of the polishing liquid) The pH of the polishing liquid was measured under the following conditions. The results are shown in each table. Measurement temperature: 25°C Measuring device: Product name: Model (D-71) manufactured by Horiba, Ltd. Measurement method: After three-point calibration of the pH meter using phthalate pH standard solution (pH: 4.01), neutral phosphate pH standard solution (pH: 6.86), and borate pH standard solution (pH: 9.18) as pH standard solutions, the electrode of the pH meter was put into the polishing liquid, and after 2 minutes or more had passed and it had stabilized, the pH was measured with the above-mentioned measuring device.

[0125] (pH of the 1 mM solution of the compound) A 1 mM (millimolar concentration) solution was prepared by dissolving each of the following compounds in deionized water. The pH of the solution was measured in the same procedure as the pH of the polishing liquid. The pH of the 1 mM solution of each compound was as follows. Aminoacetic acid: 5.9 L-Histidine: 7.5 3-Hydroxypyridine: 6.7 4-Hydroxypyridine: 6.2 2-Pyridineethanol: 7.2 2-Methylimidazole: 9.2 Imidazole: 8.6 Triethanolamine: 9.4

[0126] <Evaluation of polishing characteristics> (Preparation of evaluation wafer) As blanket wafers (BKW), we prepared a φ200 mm unpatterned wafer having a silicon oxide film (SiO2, initial film thickness: 1000 nm) on its surface, and a φ200 mm unpatterned wafer having a silicon nitride film (SiN, initial film thickness: 200 nm) on its surface.

[0127] A test patterned wafer (model number: Sematech864, manufactured by Advantec Co., Ltd., φ200 mm) with a silicon oxide film (initial film thickness: 600 nm) having a concave-convex pattern on the surface was prepared as a patterned wafer (PTW). The convex part (line part) has an initial step height of 500 nm higher than the concave part (space part), and the convex part has a silicon nitride film (initial film thickness: 140 nm) as a stopper for the silicon oxide film under the assumption of evaluation for shallow trench isolation. The patterned wafer has multiple 20 mm × 20 mm die units, and multiple 4 mm × 4 mm unit areas within each die unit. The patterned wafer has an area with a 4 mm × 4 mm unit area having a parallel line pattern with a pitch of 100 μm and a line / space (L / S) of 10 μm / 90 μm (convex density: 10%) to 90 μm / 10 μm (convex density: 90%) in 10 μm increments.

[0128] (Polishing procedure) The above-mentioned evaluation wafer was polished using a polishing device (Applied Materials, product name: Mirra3400). The above-mentioned evaluation wafer was set on a holder having an adsorption pad for mounting a substrate. A polishing pad made of porous urethane resin (K-groove groove, DuPont (Dow), model number: IC-1010) was attached to a polishing platen with a diameter of 500 mm.

[0129] The holder was placed on the polishing pad with the surface of the evaluation wafer facing downward. The inner tube pressure, the retaining ring pressure, and the membrane pressure were set to 14 kPa, 21 kPa, and 14 kPa, respectively.

[0130] Then, the polishing pad attached to the polishing platen was subjected to a 93-minute period while the above-mentioned polishing liquid was dropped onto the polishing pad at a flow rate of 200 mL / min. -1 and 87 min. -1 The polished surface was polished by rotating the wafer at a speed of 1000 rpm. For blanket wafers, polishing was performed for 30 seconds. For patterned wafers, the polishing time was set to the time at which the silicon nitride film underlying the silicon oxide film was not exposed in the convex parts of the L / S=20μm / 80μm ​​region, within the range of 20 to 60 seconds, depending on the polishing speed evaluated for the blanket wafer, and polishing was performed for that polishing time. Next, the evaluation wafer after polishing was thoroughly washed with pure water using a PVA brush (polyvinyl alcohol brush) and then dried.

[0131] (Evaluation of polishing speed) The change in thickness of the film being polished before and after polishing was measured using an optical interference film thickness measuring device (Nanometrics Japan, product name: AFT-5100) as shown below, and the polishing rate was obtained. In addition, the polishing rate ratio (PTW / BKW) of silicon oxide on the convex part of the patterned wafer to silicon oxide on the blanket wafer was calculated. The results are shown in each table.

[0132] For blanket wafers, the change in film thickness was measured at a total of 41 measurement points (20 points on both sides of the center point), including the center point of the wafer and points spaced 5 mm apart from the center in the diametric direction (the next measurement point after the measurement point 95 mm from the center was 97 mm from the center). The change in film thickness over a 30-second polishing time was measured at these 41 points, and the average value was obtained as the polishing rate for the blanket wafer.

[0133] For the patterned wafer, the amount of film thickness change at the convex part of the L / S=20μm / 80μm ​​area was measured to obtain the polishing rate of the patterned wafer. In the central die unit (20mm×20mm) of the patterned wafer, the amount of film thickness change at one central location of one unit area (4mm×4mm) of L / S=20μm / 80μm ​​was measured.

[0134] [Table 1]

[0135] [Table 2]

[0136] [Table 3]

[0137] [Table 4] [Explanation of symbols]

[0138] 10...ILD film, 20...wiring, 30...silicon oxide film, 40...contact plug, 100, 100a...substrate, D...step.

Claims

1. The method includes the steps of: the abrasive grains include cerium-based particles; The additive comprises (A1) a 4-pyrone compound represented by the following general formula (1), (B) a saturated monocarboxylic acid, and (C) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded, A polishing solution for CMP having a pH of more than 4.

0. 【Chemistry 1】 [In the formula, X １１ , X １２ and X １３ are each independently a hydrogen atom or a monovalent substituent.

2. 2. The polishing slurry for CMP according to claim 1, wherein the component (A1) comprises at least one member selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone, 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and 2-ethyl-3-hydroxy-4-pyrone.

3. 2. The polishing slurry for CMP according to claim 1, wherein the content of the component (A1) is 0.001 to 5 mass %.

4. 2. The polishing liquid for CMP according to claim 1, wherein the component (C) contains ethylenedinitrilotetraethanol.

5. 2. The polishing liquid for CMP according to claim 1, wherein the component (C) contains ethylenedinitrilotetrapropanol.

6. The polishing liquid for CMP according to claim 1 , wherein the additive further comprises hydroxypyridine.

7. 2. The polishing liquid for CMP according to claim 1, wherein the additive further comprises L-histidine.

8. The method includes the steps of: the abrasive grains include cerium-based particles; the additive comprises (A2) picolinic acid, (B) a saturated monocarboxylic acid, and (C) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded; A polishing solution for CMP having a pH of more than 4.

0.

9. The CMP polishing liquid according to claim 8, wherein the component (C) contains ethylenedinitrilotetraethanol.

10. The CMP polishing liquid according to claim 8, wherein the component (C) comprises ethylenedinitrilotetrapropanol.

11. A method for producing a polishing material comprising the steps of: the abrasive grains include cerium-based particles; The additive comprises (A2) picolinic acid and (B) a saturated monocarboxylic acid, The content of the (A2) component is 0.001 to 5 mass %, A polishing solution for CMP having a pH of more than 4.

0.

12. 12. The polishing slurry for CMP according to claim 1, wherein the component (B) contains propionic acid.

13. 12. The polishing slurry for CMP according to claim 1, wherein the content of the component (B) is 0.0001 to 5 mass %.

14. The polishing liquid for CMP according to any one of claims 1 to 11, having a pH of 8.0 or less.

15. A polishing liquid set for CMP, comprising: a first liquid and a second liquid, the components of which are stored separately from each other in the polishing liquid for CMP according to any one of claims 1 to 11; the first liquid containing the abrasive grains and water; and the second liquid containing at least one of the additives and water.

16. A polishing method comprising a step of polishing a surface to be polished with the polishing slurry for CMP according to any one of claims 1 to 11.

17. The polishing method according to claim 16 , wherein the surface to be polished comprises silicon oxide.

18. 16. A polishing method comprising the step of polishing a surface to be polished with a polishing liquid for CMP obtained by mixing the first liquid and the second liquid in the polishing liquid set for CMP according to claim 15.

19. The polishing method according to claim 18 , wherein the surface to be polished comprises silicon oxide.

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