CMP polishing liquid, CMP polishing liquid set, and polishing method

Abstract

To provide a polishing liquid for CMP that can achieve a high removal rate of silicon oxide on the protruding portions when polishing a patterned wafer having a fine uneven pattern.SOLUTION: A polishing liquid for CMP includes an abrasive grain, an additive, and water, the abrasive grain contains cerium-based particles, the average particle size of the abrasive grain exceeds 100 nm, the additive contains (A) a 4-pyrone-based compound represented by the following general formula (1), and (B2) a cyclic compound having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group, an amino group, and a hydroxy group, the mass ratio of the content of the component (B2) to the content of the component (A) is 0.1 to 10. [X11, X12, and X13 are each independently a hydrogen atom or a monovalent substituent.]SELECTED DRAWING: None

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 Art

[0002] In the field of semiconductor manufacturing, with the increasing performance of ultra-LSI devices, it has become difficult to achieve both high integration and high speed by miniaturization technology that is an extension of the prior art. Therefore, while promoting the miniaturization of semiconductor elements, technologies for achieving high integration also in the vertical direction (that is, technologies for multilayer wiring) have been developed.

[0003] One of the most important technologies in the process of manufacturing a device with multilayer wiring is CMP technology. CMP technology is a technology for planarizing the surface of a substrate obtained by forming a thin film on the substrate by chemical vapor deposition (CVD) or the like. For example, in order to ensure the depth of focus of lithography, planarization processing by CMP is indispensable. If there are irregularities on the surface of the substrate, inconveniences such as impossibility of focusing in the exposure process or inability to sufficiently form a fine wiring structure will occur. In addition, CMP technology is also applied to a process of forming an element isolation (isolation between elements. STI: shallow trench isolation) region by polishing a plasma oxide film (BPSG, HDP-SiO2, p-TEOS, etc.) in the manufacturing process of a device; a process of forming an ILD film (interlayer insulating film. An insulating film that electrically insulates metal members (wiring, etc.) in the same layer); a process of planarizing a plug (for example, an Al·Cu plug) after embedding a film containing silicon oxide in a metal wiring.

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

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

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, with cerium-based polishing liquids, it may be difficult to achieve a high polishing rate of silicon oxide. In particular, in the polishing of a patterned wafer having a fine concavo-convex pattern composed of convex portions (e.g., Line portions) and concave portions (e.g., Space portions), it may be difficult to achieve a high polishing rate of silicon oxide in the convex portions.

[0008] One aspect of the present disclosure aims to provide a polishing liquid for CMP capable of achieving a high polishing rate of silicon oxide in the convex portions in the polishing of a patterned wafer having a fine concavo-convex pattern. Another aspect of the present disclosure aims to provide a polishing liquid set for CMP for obtaining the polishing liquid for CMP. Still another aspect of the present disclosure aims to provide a polishing method using the polishing liquid for CMP or the polishing liquid set for CMP.

Means for Solving the Problems

[0009] The present disclosure relates to the following [1] to

[25] and the like in some aspects. [1] A polishing liquid for CMP containing abrasive grains, an additive, and water, wherein the abrasive grains contain cerium-based particles, and the additive contains (A) a 4-pyrone compound represented by the following general formula (1) and (B1) a compound having a pH of 3.7 or more in a 1 mM aqueous solution.

Chemical formula

[10] The polishing liquid for CMP according to [8] or [9], wherein the component (B2) contains at least one selected from the group consisting of aromatic aminocarboxylic acids, quinolinecarboxylic acids, pyridinecarboxylic acids, and salts thereof.

[11] The polishing liquid for CMP according to any one of [8] to

[10] , wherein the component (B2) contains at least one selected from the group consisting of quinaldic acid and salts thereof.

[12] The polishing liquid for CMP according to any one of [8] to

[11] , wherein the component (B2) contains at least one selected from the group consisting of anthranilic acid and salts thereof.

[13] The polishing liquid for CMP according to any one of [8] to

[12] , wherein the component (B2) contains at least one selected from the group consisting of picolinic acid and its salts.

[14] The polishing liquid for CMP according to any one of [8] to

[13] , wherein the content of the component (B2) is 0.001 to 5% by mass.

[15] A polishing liquid for CMP, comprising abrasive grains, an additive, and water, wherein the abrasive grains contain cerium-based particles, and the additive contains a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

[16] The polishing liquid for CMP according to

[15] , wherein the compound having two or more nitrogen atoms to which the hydroxyalkyl group is bonded contains ethylenedinitrilotetraethanol.

[17] The polishing liquid for CMP according to

[15] or

[16] , wherein the pH of the polishing liquid for CMP is 8.0 or less.

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

[17] , wherein the cerium-based particles contain cerium oxide.

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

[18] , wherein the content of the abrasive grains is 0.01 to 10% by mass.

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

[19] , wherein the component (A) contains at least one 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.

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

[20] , wherein the content of the component (A) is 0.001 to 5% by mass.

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

[21] , wherein the additive further contains a saturated monocarboxylic acid.

[23] The polishing liquid for CMP according to

[22] , wherein the content of the saturated monocarboxylic acid is 0.0001 to 5% by mass.

[24] The components of the polishing liquid for CMP according to any one of [1] to

[23] are stored separately as a first liquid and a second liquid. The first liquid contains the abrasive grains and water, and the second liquid contains at least one of the additives and water. A polishing liquid set for CMP. A polishing method comprising a step of polishing a surface to be polished using a polishing liquid for CMP according to any one of

[25] [1] to

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

[24] . The polishing method according to

[25] , wherein the surface to be polished contains silicon oxide.

Advantages of the Invention

[0010] According to one aspect of the present disclosure, it is possible to provide a polishing liquid for CMP capable of achieving a high polishing rate of silicon oxide in the convex portions in the polishing of a pattern wafer having a fine uneven pattern. Further, according to another aspect of the present disclosure, it is possible to provide a polishing liquid set for CMP for obtaining the polishing liquid for CMP. Furthermore, according to another aspect of the present disclosure, it is possible to provide a polishing method using the polishing liquid for CMP or the polishing liquid set for CMP.

Brief Description of the Drawings

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described in detail.

[0013] In this specification, a numerical range indicated by using "~" 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 numerical range at a certain step can be arbitrarily combined with the upper limit value or the lower limit value of a numerical range at another step. 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 value 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 thereof 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 when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified. The terms "layer" or "film" include not only a structure formed over the entire surface but also a structure formed partially when observed as a plan view. The term "step" includes not only an independent step but also a step in which the intended action of the step is achieved even when it cannot be clearly distinguished from other steps. "(Meth)acrylate" means at least one of acrylate and the corresponding methacrylate. The same applies to other similar expressions such as "(meth)acrylic acid".

[0014] <Polishing liquid for CMP> The polishing liquid for CMP according to this embodiment (the first embodiment, the second embodiment, and the third embodiment; the same shall apply hereinafter) is a polishing liquid for CMP (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 (A) a 4-pyrone-based compound represented by the following general formula (1) ((A) component) and (B1) a compound having a pH of 3.7 or more in an aqueous solution of 1 mM (millimolar concentration) ((B1) component). The additive of the polishing liquid according to the second embodiment includes (A) a 4-pyrone-based compound represented by the following general formula (1) ((A) component) and (B2) a cyclic compound having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group, an amino group, and a hydroxy group (hydroxyl group) ((B2) component). The additive of the polishing liquid according to the third embodiment includes a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded (hereinafter, sometimes referred to as "nitrogen-containing hydroxyalkyl compound"; ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, etc.). The nitrogen-containing hydroxyalkyl compound may be either a compound corresponding to the (B1) component or a compound not corresponding to the (B1) component, and ethylenedinitrilotetraethanol and ethylenedinitrilotetrapropanol are compounds corresponding to the (B1) component. The additive of the polishing liquid according to this embodiment may include the (A) component, the (B1) component, and the (B2) component.

[0015] [Chemical formula] [In the formula, X 11 , X 12 and X 13 are each independently a hydrogen atom or a monovalent substituent.]

[0016] According to the polishing liquid of the present embodiment, in the polishing of a patterned wafer having a fine concavo-convex pattern composed of convex portions (for example, Line portions) and concave portions (for example, Space portions), it is possible to achieve a high polishing rate of silicon oxide in the convex portions. For example, in the polishing of a region where Line / Space (L / S) = 20 μm / 80 μm in the patterned wafer, a high polishing rate of silicon oxide in the convex portions can be achieved (according to the polishing liquid of the present embodiment, in the evaluation method described in the examples below, as the polishing rate of silicon oxide in the convex portions in the region where L / S = 20 μm / 80 μm, for example, 300 nm / min or more can be obtained).

[0017] Although the factors contributing to such an effect are not necessarily clear, it is presumed to be as follows. However, the factors are not limited to the following content. That is, by using the component (A), the interaction between the polishing liquid and silicon oxide is increased, and by using the component (B1) or the component (B2), the interaction between the polishing liquid and silicon oxide is also increased. However, when the component (A) is used without using the components (B1) and (B2), and when the component (A) is not used and the component (B1) or the component (B2) excluding the nitrogen-containing hydroxyalkyl compound (ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, etc.) is used, even if it is possible to perform high-speed polishing of silicon oxide on a blanket wafer having no uneven pattern by using cerium-based particles having a lower hardness than silica-based particles, a high polishing rate of silicon oxide at the convex portions of the pattern wafer cannot be achieved. In particular, a specific phenomenon has been confirmed in which a high polishing rate of silicon oxide at the convex portions cannot be achieved in the polishing of the region of L / S = 20 μm / 80 μm in the pattern wafer. On the other hand, according to the polishing liquids according to the first and second embodiments, due to the synergistic effect resulting from the use of the component (A) and the component (B1) or the component (B2), the interaction between the polishing liquid and the silicon oxide at the convex portions is increased (for example, the chemical reaction (reaction derived from the Si-O-Ce bond) between the cerium-based particles in the polishing liquid and the silicon oxide at the convex portions is promoted), so that it is possible to obtain a high polishing rate of the silicon oxide at the convex portions, and a high polishing rate of the silicon oxide at the convex portions can be achieved in the polishing of the region of L / S = 20 μm / 80 μm in the pattern wafer. Further, according to the polishing liquid according to the third embodiment, even when the component (A) is not used, a similar effect can be obtained by using a nitrogen-containing hydroxyalkyl compound (ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, etc.).

[0018] According to one aspect of the polishing liquid according to the present embodiment, while achieving high-speed polishing of silicon oxide (for example, a polishing rate of 100 nm / min or more (preferably 250 nm / min or more, etc.)) on a blanket wafer having no uneven pattern, a high polishing rate of silicon oxide on the convex portions can be achieved in the polishing of the region of L / S = 20 μm / 80 μm on the patterned wafer.

[0019] According to one aspect of the polishing liquid according to the present embodiment, a high polishing rate of silicon oxide on the convex portions can also be achieved in the polishing of the region of L / S = 30 μm / 70 μm on the patterned wafer.

[0020] According to one aspect of the polishing liquid according to the present embodiment, even when using abrasive grains with a small particle size or when the content of abrasive grains is low, a high polishing rate of silicon oxide on the convex portions can be obtained in the polishing of the patterned wafer.

[0021] In the step of forming the 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 there may be a case where a high polishing selectivity of silicon oxide with respect to silicon nitride (polishing rate of silicon oxide / polishing rate of silicon nitride) is required. According to one aspect of the polishing liquid according to the present embodiment, it is possible to obtain a sufficiently small polishing rate of silicon nitride and a high polishing selectivity of silicon oxide with respect to silicon nitride. In this case, it is suitable for polishing when forming the element isolation region. According to one aspect of the polishing liquid according to the present embodiment, in the evaluation method described in the examples below, a polishing rate of silicon nitride on the blanket wafer of less than 2.0 nm / min (preferably less than 1.0 nm / min, etc.) can be obtained.

[0022] According to one aspect of the polishing liquid according to the present embodiment, in the polishing of a patterned wafer having a square convex pattern (convex density: 100%) and a square concave pattern (convex density: 0%), as an index of dishing characteristics, the polishing rate of the concave pattern (convex density: 0%) can be suppressed. In this case, for example, in the polishing of the silicon oxide film of the convex portion in a patterned wafer having a silicon oxide film on the surface (including, for example, a patterned wafer having a silicon nitride film as an underlying stopper in the case of STI formation), when polishing the silicon oxide film corresponding to the thickness of the initial step, the polishing of the silicon oxide film in the concave portion also proceeds, or the silicon oxide film in the concave portion in a pattern with a sufficiently wide width is polished faster than the silicon oxide film in the convex portion, so that the phenomenon (dishing) in which the concave portion is depressed like a dish can be easily suppressed. According to one aspect of the polishing liquid according to the present embodiment, in the evaluation method described in the examples below, the polishing rate of 0% convex portion can be, for example, 500 nm / min or less (preferably, 300 nm / min or less, 200 nm / min or less, etc.).

[0023] According to one aspect of the polishing liquid according to the present embodiment, in the polishing of a patterned wafer having a square convex pattern (convex density: 100%) and a square concave pattern (convex density: 0%), as an index of planarization efficiency, a high polishing rate ratio of convex 100% / convex 0% can be obtained. According to one aspect of the polishing liquid according to the present embodiment, in the evaluation method described in the examples below, a polishing rate ratio of convex 100% / convex 0% exceeding 1.0 can be obtained.

[0024] The polishing liquid according to the present embodiment can be used for CMP of semiconductor wafer materials, and can be used, 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 the ILD film. According to one aspect of the polishing liquid according to the present embodiment, while obtaining a high polishing rate, aggregation of abrasive grains and generation of polishing scratches can be suppressed, and high flatness can be obtained.

[0025] (Abrasive grains) The abrasive grains contain cerium-based particles. By using cerium-based particles as the abrasive grains, it is easy to obtain a high polishing rate of silicon oxide on the convex portions of the patterned wafer while reducing polishing scratches on the surface to be polished.

[0026] Examples of the cerium-based compound of the cerium-based particles include cerium oxide, cerium hydroxide, cerium ammonium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, cerium carbonate, and the like. The cerium-based particles may contain cerium oxide from the viewpoint that it is easy to obtain a high polishing rate of silicon oxide on the convex portions (such as the convex portions in the region of L / S = 20 μm / 80 μm, the convex portions in the region of L / S = 30 μm / 70 μm, etc.; the same applies hereinafter) of the patterned wafer. By using cerium-based particles containing cerium oxide (cerium oxide particles), it is easy to achieve a high polishing rate of silicon oxide on the convex portions of the patterned wafer, and it is easy to obtain a polished surface with few polishing scratches and excellent flatness.

[0027] The cerium oxide particles may contain polycrystalline cerium oxide having grain boundaries. Such polycrystalline cerium oxide particles have the property that they become finer during polishing and at the same time active surfaces appear one after another, and can highly maintain a high polishing rate of silicon oxide on the convex portions of the patterned wafer.

[0028] Examples of the method for producing cerium oxide particles include a firing method; an oxidation method using hydrogen peroxide or the like. When firing, the temperature during firing may be 350 to 900°C. When the produced cerium oxide particles are aggregated, the particles may be mechanically pulverized. Examples of the pulverization method may include dry pulverization using a jet mill or the like, or wet pulverization using a planetary ball mill or the like. As the jet mill, for example, those described in "Journal of Chemical Engineering of Japan", Vol. 6, No. 5, (1980), pp. 527 to 532 can be used.

[0029] The zeta potential (surface potential) of abrasive grains in the abrasive liquid may be positive (the zeta potential may exceed 0 mV) from the viewpoints of easily obtaining a high polishing rate of silicon oxide at the convex portions of the patterned wafer and 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 type zeta potential measuring device (for example, manufactured by Beckman Coulter, Inc., trade name: DelsaNano C). The zeta potential of the abrasive grains can be adjusted using an additive. For example, by bringing an acid component (for example, acetic acid) into contact with the abrasive grains, abrasive grains having a positive zeta potential can be obtained.

[0030] 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 viewpoints of easily obtaining a high polishing rate of silicon oxide at the convex portions of the patterned wafer and 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 viewpoints of easily suppressing the generation of polishing scratches and efficiently obtaining the effect of improving flatness such as suppressing dishing of the patterned wafer. 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-speed polishing rate of silicon oxide corresponding to the average particle size of the abrasive grains and low scratch characteristics can be efficiently obtained.

[0031] "Average grain size of abrasive grains" means the median value of the volume distribution measured by a laser diffraction / scattering particle size distribution analyzer for a sample of slurry in which abrasive grains are dispersed, and it can be measured using products such as Microtrac MT3300EXII manufactured by MicrotracBEL Corp. For example, a sample is prepared by dispersing abrasive grains in water so that the content of abrasive grains becomes 0.25% by mass based on the total mass of the sample to adjust the content of abrasive grains, and this sample is set in the measuring device to measure the median value of the volume distribution. When measuring the particle size of abrasive grains in a polishing liquid, a sample can be prepared by adjusting the content of abrasive grains in the polishing liquid so that the content of abrasive grains becomes 0.25% by mass based on the total mass of the sample, and it can be measured in the same manner using this sample.

[0032] The content of abrasive grains may be in the following range based on the total mass of the polishing liquid from the viewpoint of excellent balance between the polishing rate of silicon oxide in the convex portion of the pattern wafer and the dispersion stability of the abrasive grains. The content of abrasive grains may be 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.15% by mass or more, 0.2% by mass or more, 0.25% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.8% by mass or more, or 1% by mass or more. The content of abrasive grains may be 10% by mass or less, 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, or 0.25% by mass or less. From these viewpoints, the content of abrasive grains may be 0.01 - 10% by mass, 0.01 - 1% by mass, 0.01 - 0.5% by mass, 0.01 - 0.25% by mass, 0.05 - 10% by mass, 0.05 - 1% by mass, 0.05 - 0.5% by mass, 0.05 - 0.25% by mass, 0.1 - 10% by mass, 0.1 - 1% by mass, 0.1 - 0.5% by mass, or 0.1 - 0.25% by mass.

[0033] (Additive) [Component (A): 4-pyrone-based compound] The additives for the polishing liquid according to the first and second embodiments contain, as component (A), a 4-pyrone compound represented by the general formula (1) (hereinafter, sometimes simply referred to as "4-pyrone compound"). By using the 4-pyrone compound, it is presumed that the interaction between the polishing liquid and silicon oxide increases, and thus the polishing rate tends to be high. Also, although the 4-pyrone compound is an additive that can enhance the interaction between the polishing liquid and silicon oxide, it is considered that it can suppress the aggregation of abrasive grains because it has no effect of weakening repulsive forces such as the electrostatic repulsive force between abrasive grains.

[0034] The 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 a carbon atom adjacent to the carbon atom of the carbonyl group. The "4-pyrone compound" is a heterocyclic compound having an oxy group and a carbonyl group, and having a γ-pyrone ring (6-membered ring) in which the carbonyl group is located at the 4-position with respect to the oxy group. In the 4-pyrone compound, a hydroxy group is bonded to a carbon atom adjacent to the carboxy group in this γ-pyrone ring, and substituents other than a hydrogen atom may be substituted on the other carbon atoms.

[0035] [Chemical formula]

[0036] 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 phosphoric acid group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, a nitro group, a hydrazine group, an alkyl group (for example, an alkyl group having 1 to 8 carbon atoms), an aryl group (for example, an aryl group having 6 to 12 carbon atoms), an alkenyl group (for example, an alkenyl group having 1 to 8 carbon atoms), and the like. The alkyl group, aryl group, and alkenyl group may be substituted with OH, COOH, Br, Cl, I, NO2, etc. X 11 , X 12 and X13 When having a monovalent substituent, the substituent may be bonded to the carbon atom adjacent to the oxy group, that is, X 11 and X 12 may be the substituent. X 11 , X 12 and X 13 At least two of them may be hydrogen atoms.

[0037] From the viewpoints of easily obtaining a high polishing rate of silicon oxide in the convex portions of the pattern wafer and easily suppressing the aggregation of abrasive grains, the 4-pyrone 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. The 4-pyrone compound can be used alone or in combination of two or more. When using two or more 4-pyrone compounds in combination, in addition to improving the polishing rate of the flat surface to be polished, there is also a tendency to obtain the effect of improving the in-plane uniformity.

[0038] The 4-pyrone compound may be water-soluble. By using a compound with a high solubility in water, a desired amount of the additive can be well dissolved in the polishing liquid, and the effects of improving the polishing rate and suppressing the aggregation of abrasive grains can be achieved at an even 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 limitation on the upper limit of the solubility.

[0039] 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 that the effect of improving the polishing rate of the convex portions on the pattern wafer can be obtained more efficiently. The content of the 4-pyrone compound 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, 0.032% by mass or more, 0.034% by mass or more, 0.035% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.08% by mass or more, 0.1% by mass or more, 0.13% by mass or more, 0.15% by mass or more, 0.18% by mass or more, or 0.2% by mass or more. The content of the 4-pyrone compound may be 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% by mass or less, 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% by mass, 0.001 to 1% by mass, 0.001 to 0.3% by mass, 0.001 to 0.1% by mass, 0.001 to 0.05% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.3% by mass, 0.01 to 0.1% by mass, 0.01 to 0.05% by mass, 0.02 to 5% by mass, 0.02 to 1% by mass, 0.02 to 0.3% by mass, 0.02 to 0.1% by mass, or 0.02 to 0.05% by mass.

[0040] The mass ratio A (4-pyrone compound / abrasive grains) of the content of the 4-pyrone compound to the content of the abrasive grains may be in the following range from the viewpoint that the effect of improving the polishing rate of the convex portions on the pattern wafer can be obtained more efficiently. 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.

[0041] [Component (B1): A compound with a pH of 3.7 or more in an aqueous solution of 1 mM] The additive for the polishing liquid according to the first embodiment contains component (B1) (excluding the compound corresponding to component (A)). The additive for the polishing liquid according to the third embodiment may contain, as the compound corresponding to component (B1) (nitrogen-containing hydroxyalkyl compound), for example, ethylenedinitrilotetraethanol or ethylenedinitrilotetrapropanol. As component (B1), a compound that also corresponds to component (B2) can be used. By using component (B1), the interaction between the polishing liquid and the silicon oxide of the convex portion in the uneven pattern can be increased, and a high polishing rate of the silicon oxide of the convex portion can be obtained. Since a compound capable of acid dissociation in multiple stages has multiple pKa values, although it is complicated to select an effective compound based on pKa, according to the polishing liquid according to the first embodiment, such complication can be avoided by selecting the compound based on the pH provided by the compound in a 1 mM aqueous solution. According to the first embodiment, it is possible to provide a method for selecting an additive for the polishing liquid based on the pH provided in a 1 mM aqueous solution, and as an additive for the polishing liquid capable of achieving a high polishing rate of the silicon oxide of the convex portion in the polishing of a pattern wafer having a fine uneven pattern, a method for selecting an additive for the polishing liquid based on the pH provided in a 1 mM aqueous solution can be provided.

[0042] (B1) The pH (25 °C) of a 1 mM aqueous solution of the component is 3.7 or higher from the viewpoint of obtaining a high polishing rate of silicon oxide on the convex portions of the pattern wafer. The pH of a 1 mM aqueous solution of the (B1) component may be in the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the pattern wafer. The pH of a 1 mM aqueous solution of the (B1) component may be 3.8 or higher, 4.0 or higher, 4.5 or higher, 5.0 or higher, over 5.0, 5.4 or higher, 5.5 or higher, 5.6 or higher, 5.8 or higher, 5.9 or higher, 6.0 or higher, 6.2 or higher, 6.5 or higher, 6.7 or higher, 7.0 or higher, 7.2 or higher, 7.5 or higher, 8.0 or higher, 8.5 or higher, 8.6 or higher, 9.0 or higher, 9.2 or higher, 9.4 or higher, 9.5 or higher, 9.8 or higher, 10.0 or higher, or 10.2 or higher. The pH of a 1 mM aqueous solution of the (B1) component may be 14.0 or lower, 13.0 or lower, 12.0 or lower, 11.0 or lower, 10.5 or lower, 10.2 or lower, 10.0 or lower, 9.8 or lower, 9.5 or lower, 9.4 or lower, 9.2 or lower, 9.0 or lower, 8.6 or lower, 8.5 or lower, 8.0 or lower, 7.5 or lower, 7.2 or lower, 7.0 or lower, 6.7 or lower, 6.5 or lower, 6.2 or lower, 6.0 or lower, 5.9 or lower, 5.8 or lower, 5.6 or lower, 5.5 or lower, or 5.4 or lower. From these viewpoints, the pH of a 1 mM aqueous solution of the (B1) component 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 the (B1) component is a mixture composed of the (B1) component and water.

[0043] (B1) Components 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, 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.), triethanolamine (2,2’,2’’-nitrilotriethanol, etc.).

[0044] Examples of the amino acids include histidine (such as L-histidine), lysine, arginine, glutamine (such as L-glutamine), glutamic acid (such as L-glutamic acid), proline (such as L-proline), bicine, cysteine (such as L-cysteine), alanine (such as L-alanine), serine (such as L-serine), aminoacetic acid (glycine), tyrosine (such as L-tyrosine), phenylalanine, etc. The amino acid may be a basic amino acid or an aromatic amino acid. Examples of the pyridine compounds include pyridine, hydroxypyridine (such as 3-hydroxypyridine, 4-hydroxypyridine), pyridinecarboxylic acid (such as nicotinic acid, picolinic acid), methylpyridine (such as 2-methylpyridine), acetylpyridine (such as 2-acetylpyridine), pyridineethanol (such as 2-pyridineethanol), aminopyridine (such as 3-aminopyridine), etc. Examples of the imidazole compounds include imidazole, methylimidazole (such as 2-methylimidazole), dimethylimidazole (such as 1,2-dimethylimidazole), etc. Examples of the pyrazole compounds include pyrazole, methylpyrazole, etc. Examples of the triazole compounds include triazole (such as 1,2,4-triazole), aminotriazole (such as 3-amino-1,2,4-triazole), etc. Examples of the compounds containing an amino group and a benzene ring include aminobenzene (aniline), anthranilic acid, etc.

[0045] (B1) component 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, ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, and triethanolamine. It may contain at least one selected from the group consisting of amino acids, pyridine compounds, imidazole compounds, pyrazole compounds, triazole compounds, and ethylenedinitrilotetraethanol. It may contain at least one selected from the group consisting of basic amino acids, aromatic amino acids, aminoacetic acid, hydroxypyridine, methylpyridine, acetylpyridine, pyridineethanol, aminopyridine, imidazole, pyrazole, triazole, ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, and triethanolamine. It may contain at least one selected from the group consisting of basic amino acids, aromatic amino acids, aminoacetic acid, hydroxypyridine, methylpyridine, acetylpyridine, pyridineethanol, aminopyridine, imidazole, pyrazole, triazole, ethylenedinitrilotetraethanol, and triethanolamine. It may contain at least one selected from the group consisting of histidine, glutamine, glutamic acid, proline, bicine, cysteine, alanine, serine, aminoacetic acid, tyrosine, hydroxypyridine, pyridineethanol, imidazole, methylimidazole, ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, and triethanolamine. In particular, the (B1) component may be in a form containing hydroxypyridine, a form containing ethylenedinitrilotetraethanol, a form containing ethylenedinitrilotetrapropanol, or a form containing triethanolamine. From the viewpoint of easily obtaining a high polishing rate of silicon oxide in the convex portion of the pattern wafer, the (B1) component may contain a compound that does not correspond to an aromatic polyoxyalkylene compound (a compound having an aromatic ring and a polyoxyalkylene chain), may contain a compound having no aromatic ring, and may contain a compound having no polyoxyalkylene chain.

[0046] (B1) component's molecular weight may be in the following range from the perspective that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained. The molecular weight of the (B1) component 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 (B1) 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, 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 perspectives, the molecular weight of the (B1) component may be 50 - 1000, 50 - 500, 50 - 300, 50 - 200, 100 - 1000, 100 - 500, 100 - 300, 100 - 200, 150 - 1000, 150 - 500, 150 - 300, or 150 - 200.

[0047] (B1) content, content of nitrogen-containing hydroxyalkyl compound (total amount of compounds corresponding to component (B1) and compounds not corresponding to component (B1); the same shall apply hereinafter), content of ethylenedinitrilotetraethanol, or content of ethylenedinitrilotetrapropanol, from the viewpoint that the effect of improving the polishing rate of silicon oxide in the convex portion of the pattern wafer, the effect of improving the polishing rate of silicon oxide in the blanket wafer, and the effect of improving the planarization efficiency can be efficiently obtained, the content B1 may be in the following range based on the total mass of the polishing liquid. The content B1 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, 0.05% by mass or more, 0.06% by mass or more, 0.08% by mass or more, 0.1% by mass or more, 0.11% by mass or more, 0.12% by mass or more, 0.13% by mass or more, 0.14% by mass or more, 0.15% by mass or more, 0.2% by mass or more, 0.25% by mass or more, 0.3% by mass or more, or 0.4% by mass or more. The content B1 may be 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, 0.25% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.14% by mass or less, 0.13% by mass or less, 0.12% by mass or less, 0.11% by mass or less, 0.1% by mass or less, 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, 0.02% by mass or less, 0.015% by mass or less, or 0.01% by mass or less. From these viewpoints, the content B1 may be 0.001 to 5% by mass, 0.001 to 1% by mass, 0.001 to 0.3% by mass, 0.001 to 0.2% by mass, 0.001 to 0.1% by mass, 0.001 to 0.05% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.3% by mass, 0.01 to 0.2% by mass, 0.01 to 0.1% by mass, 0.01 to 0.05% by mass, 0.03 to 1% by mass, 0.03 to 0.3% by mass, 0.03 to 0.2% by mass, 0.03 to 0.1% by mass, or 0.03 to 0.05% by mass.(B1) component content includes the content of compounds corresponding to (B1) component and (B2) component (the same applies hereinafter).

[0048] The mass ratio of the content of (B1) component to the content of abrasive grains ((B1) component / abrasive grains), the mass ratio of the content of nitrogen-containing hydroxyalkyl compound to the content of abrasive grains (nitrogen-containing hydroxyalkyl compound / abrasive grains), the mass ratio of the content of ethylenedinitrilotetraethanol to the content of abrasive grains (ethylenedinitrilotetraethanol / abrasive grains), or the mass ratio of the content of ethylenedinitrilotetrapropanol to the content of abrasive grains (ethylenedinitrilotetrapropanol / abrasive grains), as mass ratio B11, may be in the following range from the viewpoint of efficiently obtaining the effect of improving the polishing rate of silicon oxide in the convex portion of the pattern wafer, the effect of improving the polishing rate of silicon oxide in the blanket wafer, and the effect of improving the planarization efficiency. Mass ratio B11 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, 0.13 or more, 0.14 or more, 0.15 or more, 0.16 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.4 or more, 0.5 or more, 1 or more, or more than 1. Mass ratio B11 may be 10 or less, 5 or less, 2 or less, 1 or less, less than 1, 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, 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, 0.1 or less, 0.08 or less, 0.05 or less, or 0.01 or less. From these viewpoints, mass ratio B11 may be 0.001 - 10, 0.001 - 1, 0.001 - 0.3, 0.001 - 0.2, 0.001 - 0.1, 0.01 - 10, 0.01 - 1, 0.01 - 0.3, 0.01 - 0.2, 0.01 - 0.1, 0.1 - 10, 0.1 - 1, 0.1 - 0.3, or 0.1 - 0.2.

[0049] The mass ratio of the content of component (B1) to the content of the 4-pyrone compound ((B1) component / 4-pyrone compound), the mass ratio of the content of the nitrogen-containing hydroxyalkyl compound to the content of the 4-pyrone compound (nitrogen-containing hydroxyalkyl compound / 4-pyrone compound), the mass ratio of the content of ethylenedinitrilotetraethanol to the content of the 4-pyrone compound (ethylenedinitrilotetraethanol / 4-pyrone compound), or the mass ratio of the content of ethylenedinitrilotetrapropanol to the content of the 4-pyrone compound (ethylenedinitrilotetraethanol / 4-pyrone compound), i.e., mass ratio B12, may be in the following range from the viewpoint of efficiently obtaining the effect of improving the polishing rate of silicon oxide in the convex portion of the pattern wafer, the effect of improving the polishing rate of silicon oxide in the blanket wafer, and the effect of improving the planarization efficiency. The mass ratio B12 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 B12 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, or 0.1 or less. From these viewpoints, the mass ratio B12 may be 0.01 to 10, 0.01 to 2, 0.01 to 1, 0.1 to 10, 0.1 to 2, 0.1 to 1, 0.8 to 10, 0.8 to 2, or 0.8 to 1.

[0050] [(Component (B2): A cyclic compound having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group, an amino group, and a hydroxy group)] The additive of the polishing liquid according to the second embodiment contains a component (B2) (excluding the compound corresponding to the component (A)). By using the component (B2), the interaction between the polishing liquid and the silicon oxide of the convex portion in the uneven pattern can be increased, and thus a high polishing rate of the silicon oxide of the convex portion can be obtained. From the viewpoint of easily obtaining a high polishing rate of the silicon oxide in the convex portion of the pattern wafer, the component (B2) may have at least one selected from the group consisting of a carboxy group and a carboxylate group. As the component (B2), a compound that also corresponds to the component (B1) can be used. When it is necessary to identify to which of the component (B1) and the component (B2) such a compound should belong, the compound shall belong to the component (B2). Examples of the salt of the carboxylate group include alkali metal salts such as sodium salt and potassium salt.

[0051] (B2) component may have at least one selected from the group consisting of an aromatic ring, a heterocyclic ring (excluding the aromatic ring), 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 (B2) may have an aromatic ring different from the benzene ring.

[0052] (B2) component may contain an aromatic compound (a compound having an aromatic ring) from the viewpoint of easily obtaining a high polishing rate of the silicon oxide in the convex portion of the pattern wafer, and may contain at least one selected from the group consisting of an aromatic carboxylic acid (an aromatic compound having a carboxy group) and an aromatic carboxylate (an aromatic compound having a carboxylate group). The component (B2) 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 having no amino group and hydroxy group (quinolinecarboxylic acid, pyridinecarboxylic acid, etc.), and salts thereof, and may contain at least one selected from the group consisting of aromatic aminocarboxylic acids, quinolinecarboxylic acids, pyridinecarboxylic acids, and salts thereof.

[0053] (Component (B2) may contain at least one selected from the group consisting of benzoic acid, benzoic acid derivatives, hydroxyphenylacetic acid, alkyl salicylic acid, phthalic acid, phthalic acid derivatives, quinoline derivatives, pyridine derivatives, aminobenzenesulfonic acid, salts thereof, and salicylaldoxime, from the viewpoint that a high polishing rate of silicon oxide in the convex portions of the pattern wafer can be easily obtained, and from the viewpoint that the effect of improving the planarization efficiency can be efficiently obtained.)

[0054] 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 of silicon oxide in the convex portions of the pattern wafer. Examples of the hydroxybenzoic acid include salicylic acid (2-hydroxybenzoic acid) and 4-hydroxybenzoic acid. Examples of the aminobenzoic acid include anthranilic acid. Examples of the hydroxyphenylacetic acid include mandelic acid. Examples of the alkylsalicylic acid include methyl salicylic 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 from the viewpoint of easily obtaining a high polishing rate of silicon oxide in the convex portions of the pattern wafer. Examples of the alkylphthalic acid include methylphthalic acid (e.g., 4-methylphthalic acid). Examples of the aminophthalic acid include 4-aminophthalic acid. Examples of the sulfophthalic acid include 4-sulfophthalic acid. The quinoline derivative may contain quinolinecarboxylic acid from the viewpoint of easily obtaining a high polishing rate of silicon oxide in the convex portions of the pattern wafer. Examples of the quinolinecarboxylic acid include quinolinic acid. The pyridine derivative may contain pyridinecarboxylic acid from the viewpoint of easily obtaining a high polishing rate of silicon oxide in the convex portions of the pattern wafer. Examples of the pyridinecarboxylic acid include picolinic acid and nicotinic acid. Examples of the aminobenzenesulfonic acid include ortanilic acid. In particular, the component (B2) may be an embodiment containing at least one selected from the group consisting of quinolinic acid and its salts, an embodiment containing at least one selected from the group consisting of anthranilic acid and its salts, or an embodiment containing at least one selected from the group consisting of picolinic acid and its salts.

[0055] (B2) component may contain at least one selected from the group consisting of benzoic acid, 4-hydroxybenzoic acid, aminobenzoic acid, hydroxyphenylacetic acid, quinoline derivative, and pyridine derivative from the viewpoint of easily achieving high-speed polishing of silicon oxide (e.g., a polishing rate of 250 nm / min or more) in a blanket wafer having no uneven pattern.

[0056] (B2) component's molecular weight may be within the following range from the perspective that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained. The molecular weight of (B2) component 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 (B2) 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, 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 perspectives, the molecular weight of (B2) 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.

[0057] The content of the (B2) component may be in the following ranges based on the total mass of the polishing liquid from the viewpoints of efficiently obtaining the effect of improving the polishing rate of silicon oxide in the convex portions of the pattern wafer and easily achieving high-speed polishing of silicon oxide in a blanket wafer having no uneven pattern. The content of the (B2) component 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, 0.05% by mass or more, 0.06% by mass or more, 0.08% by mass or more, 0.1% by mass or more, 0.15% by mass or more, or 0.2% by mass or more. The content of the (B2) component may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% 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, 0.08% 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, 0.02% by mass or less, 0.015% by mass or less, or 0.01% by mass or less. From these viewpoints, the content of the (B2) component may be 0.001 to 5% by mass, 0.001 to 1% by mass, 0.001 to 0.3% by mass, 0.001 to 0.1% by mass, 0.001 to 0.05% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.3% by mass, 0.01 to 0.1% by mass, 0.01 to 0.05% by mass, 0.03 to 5% by mass, 0.03 to 1% by mass, 0.03 to 0.3% by mass, 0.03 to 0.1% by mass, or 0.03 to 0.05% by mass. The content of the (B2) component includes the content of the compounds corresponding to the (B1) component and the (B2) component (the same shall apply hereinafter).

[0058] The mass ratio B21 of the content of component (B2) to the content of abrasive grains ((B2) component / abrasive grains) may be in the following range from the viewpoints of easily obtaining a high polishing rate of silicon oxide in the convex portions of the patterned wafer and easily achieving high-speed polishing of silicon oxide in a blanket wafer having no uneven pattern. The mass ratio B21 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, 0.16 or more, 0.2 or more, 0.25 or more, or 0.3 or more. The mass ratio B21 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, 0.08 or less, 0.05 or less, or 0.04 or less. From these viewpoints, the mass ratio B21 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.

[0059] The mass ratio B22 of the content of component (B2) to the content of the 4-pyrone-based compound ((B2) component / 4-pyrone-based compound) may be in the following range from the viewpoints of easily obtaining a high polishing rate of silicon oxide in the convex portions of the patterned wafer and easily achieving high-speed polishing of silicon oxide in a blanket wafer having no uneven pattern. The mass ratio B22 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, 1 or more, 1.2 or more, 1.5 or more, or 2 or more. The mass ratio B22 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, 0.6 or less, 0.5 or less, 0.4 or less, or 0.3 or less. From these viewpoints, the mass ratio B22 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.

[0060] [Nitrogen-containing hydroxyalkyl compound] The additive of the polishing liquid according to the third embodiment contains a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded (nitrogen-containing hydroxyalkyl compound). In the nitrogen-containing hydroxyalkyl compound, the hydroxyalkyl group is directly bonded to the nitrogen atom, and the hydroxy group is directly bonded to the alkyl group directly bonded to the nitrogen atom. As the hydroxyalkyl group bonded to the nitrogen atom, an alkyl group having no substituent other than the hydroxy group can be used in the nitrogen-containing hydroxyalkyl compound.

[0061] From the viewpoint that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained, the nitrogen-containing hydroxyalkyl compound may contain a compound having a nitrogen atom to which two hydroxyalkyl groups are bonded, and may contain a compound having two or more nitrogen atoms to which two hydroxyalkyl groups are bonded.

[0062] From the viewpoint that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained, the number of nitrogen atoms in one molecule of the nitrogen-containing hydroxyalkyl compound may be 2 to 5, 2 to 4, or 2 to 3. From the viewpoint that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained, the number of hydroxy groups in one molecule of the nitrogen-containing hydroxyalkyl compound 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.

[0063] From the viewpoint that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained, the nitrogen-containing hydroxyalkyl compound may have 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 as the hydroxyalkyl group bonded to the nitrogen atom. From the viewpoint that a high polishing rate of silicon oxide in the convex portion of the pattern wafer is easily obtained, the nitrogen-containing hydroxyalkyl compound may have a hydroxyalkyl group having 1 to 3 or 1 to 2 hydroxy groups as the hydroxyalkyl group bonded to the nitrogen atom.

[0064] The nitrogen-containing hydroxyalkyl compound may have an alkylene group between two nitrogen atoms to which a hydroxyalkyl group is bonded, and the number of carbon atoms of the alkylene group may be 1 to 4, 2 to 4, 1 to 3, 2 to 3, or 1 to 2, from the viewpoint that a high polishing rate of silicon oxide at the convex portion of the pattern wafer can be easily obtained.

[0065] The nitrogen-containing hydroxyalkyl compound may contain a compound represented by the following general formula (I) from the viewpoint that a high polishing rate of silicon oxide at the convex portion of the pattern wafer can be easily obtained.

[0066] [Chemical formula] [In the formula, n is an integer of 1 or more, and R 11 , R 12 , R 13 and R 14 each independently represent a hydrogen atom or an organic group, and one or both of R 11 and R 12 are hydroxyalkyl groups, and one or both of R 13 and R 14 are hydroxyalkyl groups.]

[0067] n may be in the range described above as the number of carbon atoms of the alkylene group between two nitrogen atoms to which a hydroxyalkyl group is 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, a nitro group, and the like. When R 11 , R 12 , R 13 or R 14 is a hydroxyalkyl group, the number of carbon atoms of the hydroxyalkyl group may be in the range described above as the number of carbon atoms of the hydroxyalkyl group bonded to the nitrogen atom.

[0068] Examples of the nitrogen-containing hydroxyalkyl compound 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.), N,N,N’,N’’,N’’-pentakis(2-hydroxypropyl)diethylenetriamine, and the like. The nitrogen-containing hydroxyalkyl compound may contain at least one selected from the group consisting of ethylenedinitrilotetraethanol and ethylenedinitrilotetrapropanol, may contain ethylenedinitrilotetraethanol, or may contain ethylenedinitrilotetrapropanol, from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portions of the pattern wafer. The nitrogen-containing hydroxyalkyl compound may contain a compound having no carboxy group from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portions of the pattern wafer.

[0069] The molecular weight of the nitrogen-containing hydroxyalkyl compound may be in the following range from the viewpoint of easily obtaining a high polishing rate of silicon oxide in the convex portions of the pattern wafer. The molecular weight of the nitrogen-containing hydroxyalkyl compound 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 nitrogen-containing hydroxyalkyl compound 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 nitrogen-containing hydroxyalkyl compound 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.

[0070] The content of the nitrogen-containing hydroxyalkyl compound may be in the range as described above.

[0071] [Saturated monocarboxylic acid] The additive of the polishing liquid according to the present embodiment may contain a saturated monocarboxylic acid. By using a saturated monocarboxylic acid, it is easy to obtain a sufficiently small polishing rate of silicon nitride that can be used as a stopper material, and not only improve the dispersibility of cerium-based particles, but also improve the in-plane uniformity, which is an index of the variation in the polishing rate within the polished surface, without reducing the polishing rate of the pattern wafer (for example, a semiconductor substrate having an uneven pattern).

[0072] Examples of saturated monocarboxylic acids 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, 3,3-dimethylbutanoic acid, and the like. The saturated monocarboxylic acid may contain an aliphatic carboxylic acid from the viewpoint of easily obtaining the above-described addition effect of the saturated monocarboxylic acid. The saturated monocarboxylic acid may contain a saturated monocarboxylic acid having 2 to 6 carbon atoms, and may contain at least one selected from the group consisting of acetic acid and propionic acid, from the viewpoints of effectively obtaining the effect of suppressing the polishing rate of silicon nitride and further improving the in-plane uniformity.

[0073] The content of the saturated monocarboxylic acid (for example, saturated monocarboxylic acids having 2 to 6 carbon atoms) may be in the following ranges based on the total mass of the polishing liquid from the viewpoint that the effect of improving in-plane uniformity, the effect of improving the polishing rate of the pattern wafer, and the effect of suppressing the polishing rate of silicon nitride can be effectively obtained. The content of the saturated monocarboxylic acid may be 0.0001% by mass or more, 0.0005% by mass or more, 0.001% by mass or more, 0.002% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.045% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more. The content of the saturated monocarboxylic acid may be 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, 0.05% by mass or less, or 0.045% by mass or less. From these viewpoints, the content of the saturated monocarboxylic acid may be 0.0001 to 5% by mass, 0.0001 to 1% by mass, 0.0001 to 0.1% by mass, 0.0001 to 0.05% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.1% by mass, 0.01 to 0.05% by mass, 0.03 to 5% by mass, 0.03 to 1% by mass, 0.03 to 0.1% by mass, or 0.03 to 0.05% by mass. The content of the saturated monocarboxylic acid may be 0.04% by mass or less, 0.03% by mass or less, 0.02% by mass or less, 0.01% by mass or less, 0.005% by mass or less, 0.002% by mass or less, 0.001% by mass or less, 0.0005% by mass or less, or substantially 0% by mass.

[0074] [Nonionic polymer and cationic compound] The additive of the polishing liquid according to this embodiment may contain at least one selected from the group consisting of a nonionic polymer and a cationic compound. In this case, a protective film is formed on the surface to be polished, and high flatness can be achieved by protecting the concave surface until the convex surface is ground while maintaining the high-speed polishability of the patterned wafer. When at least one of the nonionic polymer and the cationic additive is used, such an effect can be obtained with a relatively small amount. Since there is no aggregating action like an anionic surfactant with respect to the state where the surface potential of cerium-based particles (for example, cerium oxide particles) is dispersed on the positive side, it is considered that high flatness can be obtained with less occurrence of dishing while reducing the occurrence of polishing scratches. However, the reason for the manifestation of the effect is not limited to the above content. When at least one of the nonionic polymer and the cationic additive is used, an effect of improving the in-plane uniformity of the polishing rate can also be obtained.

[0075] Examples of the nonionic polymer include ether-type surfactants such as polyglycerin, polyglycerin fatty acid ester, polyoxyethylene distyrylated phenyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene lauryl ether, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene ether derivative, polyoxypropylene glyceryl ether, polyethylene glycol, methoxypolyethylene glycol, and oxyethylene adduct of acetylene diol; ester-type surfactants such as sorbitan fatty acid ester and glycerol borate fatty acid ester; amino ether-type surfactants such as polyoxyethylene alkylamine; ether ester-type surfactants such as polyoxyethylene glycerol borate fatty acid ester and polyoxyethylene alkyl ester; alkanolamide-type surfactants such as fatty acid alkanolamide and polyoxyethylene fatty acid alkanolamide; polyvinylpyrrolidone; nonionic polyacrylamide; nonionic polydimethylacrylamide and the like. The nonionic polymer may contain an ether-type surfactant from the viewpoint of easily obtaining the above-described additive effect of the nonionic polymer.

[0076] The content of the nonionic polymer may be in the following range based on the total mass of the polishing liquid from the viewpoint that the effect of improving the in-plane uniformity of the polishing rate and the effect of improving flatness such as suppressing dishing of the pattern wafer can be efficiently obtained. The content of the nonionic polymer may be 0.05% by mass or more, 0.1% by mass or more, 0.15% by mass or more, or 0.2% by mass or more. The content of the nonionic polymer may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.3% by mass or less, or 0.2% by mass or less. From these viewpoints, the content of the nonionic polymer may be 0.05 to 5% by mass.

[0077] The cationic compound may be at least one selected from the group consisting of a cationic monomer and a cationic polymer. Examples of the cationic compound include cationic monomers such as ethyleneimine, allylamine, dimethyl(meth)acrylamide, chitosan, diallylamine, methyldiallylamine, (meth)acrylic acid, diallyldimethylammonium chloride, (meth)acrylamide, dimethylamine, epichlorohydrin, ammonia, dimethylaminoethyl (meth)acrylate, dicyandiamide, diethylenetriamine, vinylpyrrolidone·dimethylaminoethyl (meth)acrylate diethyl sulfate, diallyldimethylammonium chloride·(meth)acrylamide, diallylmethylethylammonium ethyl sulfate; cationic polymers of the cationic monomers (cationic homopolymers and cationic copolymers (dimethylamine / ammonia (NH3) / epichlorohydrin copolymer, dimethylamine / epichlorohydrin copolymer, etc.)); high molecular compounds such as derivatives of the cationic monomers; surfactants such as coconut amine acetate, stearyl amine acetate, etc. The cationic compound may contain a reaction product of a raw material containing dimethylamine and epichlorohydrin from the viewpoint that the above-mentioned addition effect regarding the cationic compound can be easily obtained. The reaction product of the raw material containing dimethylamine and epichlorohydrin may be a reaction product of a raw material containing at least dimethylamine, ammonia and epichlorohydrin.

[0078] The content of the cationic compound may be in the following range based on the total mass of the polishing liquid from the viewpoint of efficiently obtaining flatness such as suppressing dishing of the pattern wafer. The content of the cationic compound may be 0.0005% by mass or more, 0.0008% by mass or more, 0.001% by mass or more, 0.0012% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.03% by mass or more, or 0.05% by mass or more. The content of the cationic compound may be 0.5% by mass or less, 0.3% by mass or less, 0.1% by mass or less, 0.08% by mass or less, or 0.05% by mass or less. From these viewpoints, the content of the cationic compound may be 0.0005 to 0.5% by mass.

[0079] [Other Additives] The additive of the polishing liquid according to the present embodiment may further contain other components (components not corresponding to the above-mentioned respective components) according to the desired characteristics. Examples of such components include a pH adjuster described later; polar solvents such as ethanol and acetone; and cyclic monocarboxylic acids.

[0080] The polishing liquid according to the present embodiment may contain a compound a having a molecular weight of 100,000 or less and having four or more hydroxy groups, and may not contain the compound a. The content of the compound a may be 0.01% by mass or less, less than 0.01% by mass, 0.001% by mass or less, 0.0001% by mass or less, or substantially 0% by mass based on the total mass of the polishing liquid. The polishing liquid according to the present embodiment may contain a compound b having four or more amino groups, and may not contain the compound b. The content of the compound b may be 0.001% by mass or less, less than 0.001% by mass, 0.0001% by mass or less, 0.00001% by mass or less, or substantially 0% by mass based on the total mass of the polishing liquid. The mass ratio of the content of the compound a to the content of the compound b (compound a / compound b) may be 0.10 or less, or less than 0.10.

[0081] (Water) Water is not particularly limited, and may contain at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0082] (pH) The pH (25°C) of the polishing liquid according to this embodiment may be in the following ranges. From the viewpoints of suppressing agglomeration of abrasive grains, easily obtaining a high polishing rate of silicon oxide (for example, silicon oxide on the convex portions of a patterned 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 above additives, 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, 5.6 or less, 5.5 or less, less than 5.5, 5.3 or less, 5.1 or less, 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, 4.1 or less, 4.0 or less, less than 4.0, 3.8 or less, or 3.7 or less. From the viewpoint of easily suppressing the silicon oxide to be polished from having a large absolute value of zeta potential on the same positive side as the cerium-based particles (for example, cerium oxide particles) and easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, the pH may be 3.0 or more, 3.5 or more, 3.7 or more, 3.8 or more, 4.0 or more, more than 4.0, 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, 5.1 or more, 5.3 or more, 5.5 or more, more than 5.5, 5.6 or more, 6.0 or more, more than 6.0, 6.5 or more, 7.0 or more, or more than 7.0. From these viewpoints, the pH may be 3.0 to 12.0, 3.0 or more and less than 9.0, 3.0 to 8.0, 3.0 to 5.5, 3.0 to 5.0, 3.5 to 12.0, 3.5 or more and less than 9.0, 3.5 to 8.0, 3.5 to 5.5, 3.5 to 5.0, 4.0 to 12.0, 4.0 or more and less than 9.0, 4.0 to 8.0, 4.0 to 5.5, or 4.0 to 5.0. When the pH is 4.0 to 5.0, by using the component (A) and the component (B1) or the component (B2) in combination, it is particularly easy to obtain a high polishing rate on the convex portions of the patterned wafer. The polishing liquid according to the first embodiment may be an embodiment in which the component (B1) contains ethylenedinitrilotetraethanol and the pH of the polishing liquid is 8.0 or less. The pH can be measured by the method described in the examples.

[0083] When the pH is 3.0 to 5.5, in addition to the above, it is considered that the following two effects can also be obtained. (1) Protons, hydroxy anions, etc. act on the compound formulated as an additive, changing the chemical form of the compound, improving the wettability or affinity of the silicon oxide on the substrate surface, and thus making it easier to obtain a high polishing rate. (2) When the abrasive grains contain a cerium-based compound (for example, cerium oxide), the contact efficiency between the abrasive grains and silicon oxide is improved, and it is easy to achieve a high polishing rate. This is because the cerium-based compound has a positive zeta potential, while silicon oxide has a negative zeta potential, and an electrostatic attraction acts between the two.

[0084] Since the pH can 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 are no particular restrictions on the pH adjuster, but examples include acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; bases such as sodium hydroxide, ammonia (for example, aqueous ammonia), potassium hydroxide, and calcium hydroxide. The above-mentioned additives such as saturated monocarboxylic acids and aminoacetic acid may also be used for pH adjustment. From the perspective of improving productivity, the polishing liquid may be prepared without using a pH adjuster and this polishing liquid may be directly applied to CMP as it is.

[0085] <Method for preparing and using the polishing liquid> The polishing liquid according to this embodiment can be classified into (a) a normal type, (b) a concentrated type, and (c) a multi-liquid type (for example, a two-liquid type. CMP polishing liquid set), and the preparation method and usage method differ depending on the type. (a) The normal type is a polishing liquid that can be used as it is without pretreatment such as dilution during polishing. (b) The concentrated type is a polishing liquid in which the contained components are concentrated compared to (a) the normal type in consideration of the convenience of storage or transportation. (c) The multi-liquid type is a polishing liquid that is kept in a state where the contained components are divided into a plurality of liquids (for example, divided into a first liquid containing certain components and a second liquid containing other components) during storage or transportation, and these liquids are mixed and used during use.

[0086] (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 a polishing liquid with a content of 0.5 parts by mass of abrasive grains and 0.1 parts by mass of additives per 100 parts by mass of the polishing liquid, the compounding amounts may be adjusted so that there are 5 g of abrasive grains and 1 g of additives with respect to the total amount of the polishing liquid.

[0087] 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 treatment for micronizing the abrasive grains may be performed in the process of preparing the polishing liquid so that the average particle size of the abrasive grains falls within a desired range. The micronizing treatment 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 having a step of forcibly sedimenting a slurry containing abrasive grains with a centrifuge and a step of taking out only the supernatant liquid. On the other hand, the method using a high-pressure homogenizer is a method of colliding abrasive grains in a dispersion medium with high pressure.

[0088] (b) The concentrated type is diluted with water so that the content components reach a desired content immediately before use. After dilution, stirring may be performed for an arbitrary period of time until liquid characteristics (pH, particle size of abrasive grains, etc.) and polishing characteristics (polishing rate of silicon oxide, polishing selection ratio between silicon oxide and silicon nitride, etc.) comparable to those of (a) the normal type are obtained. In such a (b) concentrated type, since the volume decreases according to the degree of concentration, the costs for storage and transportation can be reduced.

[0089] 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 regarding storage and transportation are likely to be obtained as compared with the case where it 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 abrasive grains is likely to be suppressed as compared with the case where it exceeds 40 times.

[0090] (c) In the multiple - liquid type, by appropriately separating each liquid (the first liquid, the second liquid, etc.), there is an advantage that agglomeration of abrasive grains and the like can be avoided compared to the (b) concentration type. Here, the components contained in each liquid are arbitrary. (c) The 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). (c) In the multiple - liquid type, the constituent components of the CMP polishing liquid are stored separately in the first liquid and the second liquid. The first liquid contains abrasive grains and water, and the second liquid contains at least one kind selected from the group consisting of at least one kind of additive and water. (c) In the first aspect of the multiple - liquid type, the first liquid contains abrasive grains and water, and the second liquid contains component (A), at least one kind selected from the group consisting of component (B1) and component (B2), and water. (c) In the second aspect of the multiple - liquid type, the first liquid contains abrasive grains, component (A), and water, and the second liquid contains at least one kind selected from the group consisting of component (B1) and component (B2), and water. (c) In the third aspect of the multiple - liquid type, the first liquid contains abrasive grains, component (A), component (B1), and water, and the second liquid contains component (B2) and water. (c) In the fourth aspect of the multiple - liquid type, the first liquid contains abrasive grains and at least one kind selected from the group consisting of component (B1) and component (B2), and water, and the second liquid contains component (A) and water. (c) In the fifth aspect of the multiple - liquid type, the first liquid contains abrasive grains and water, and the second liquid contains a nitrogen - containing hydroxyalkyl compound (ethylenedinitrilotetraethanol, ethylenedinitrilotetrapropanol, etc.) and water. The first liquid and the second liquid may contain other components to be blended as necessary. In this case, in order to enhance the dispersibility of the abrasive grains in the first liquid, an arbitrary acid or alkali may be blended into the first liquid to adjust the pH.

[0091] (c) A polishing liquid of the multiple liquid type is useful in the case of a combination of components where the polishing characteristics tend to deteriorate in a relatively short time due to aggregation of abrasive grains or the like when mixed. From the perspective of cost reduction for storage and transportation, at least one of the liquids (the first liquid, the second liquid, etc.) may be of the concentrated type. In this case, when using the polishing liquid, each liquid and water may be mixed. The concentration ratio and pH of each liquid are arbitrary, and it is sufficient if the final mixture can be made comparable to the (a) normal type of polishing liquid in terms of liquid characteristics and polishing characteristics.

[0092] <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-described 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-described polishing liquid set.

[0093] The polishing method according to this embodiment can planarize a substrate having a silicon oxide film on its surface by CMP technology using a polishing liquid in which the content, pH, etc. of each component are adjusted. The polishing method according to this embodiment is suitable for polishing that requires high speed, high flatness, and low polishing scratches, such as polishing of an ILD film, and is suitable for applications where many ILD films are polished in a short time. According to one aspect of the polishing method according to this embodiment, the effect of improving the polishing rate of silicon oxide in a blanket wafer and the effect of improving in-plane uniformity can be efficiently obtained. According to one aspect of the polishing method according to this embodiment, since the polishing liquid according to this embodiment is used, it is possible to reduce the occurrence of polishing scratches while achieving a sufficiently high polishing rate while suppressing the aggregation of abrasive grains.

[0094] The polishing process may be a process of supplying the polishing liquid according to the present embodiment between a substrate and a polishing member (a member for polishing, such as a polishing pad), and polishing the substrate with the polishing member. The polishing method according to the present 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 the present embodiment between the silicon oxide film and the polishing member on the substrate having the silicon oxide film on its surface, and polishing the silicon oxide film with the polishing member.

[0095] The polishing method according to the present embodiment may be an aspect in which the surface to be polished has an uneven 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 uneven pattern may be 30 μm or less, or 20 μm or less. The width of the convex portions in the uneven 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 uneven 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 uneven pattern may be 80 μm or more, or 100 μm or more.

[0096] The polishing method according to the present embodiment is suitable for polishing a substrate having a silicon oxide film on its surface in the manufacturing process of a device. Examples of the device include individual 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 MMIC (Monolithic Microwave Integrated Circuit); hybrid integrated circuits (Hybrid IC); light-emitting diodes; and photoelectric conversion elements such as charge-coupled devices.

[0097] According to one aspect of the polishing liquid according to the present embodiment, a high polishing rate can be achieved without greatly depending on the uneven shape of the surface to be polished. Therefore, the polishing method using the polishing liquid can be applied to a substrate for which it has been difficult to achieve a high polishing rate with a conventional polishing liquid.

[0098] The polishing method according to the present embodiment is suitable for planarizing a surface to be polished having steps (unevenness) on the surface. Examples of the substrate having such a surface to be polished include semiconductor devices for logic. Further, the polishing method according to the present embodiment is suitable for polishing a surface including a portion where a concave portion or a convex portion has a T shape or a lattice shape when viewed from above. For example, the polishing method according to the present embodiment can also polish a silicon oxide film provided on the surface of a semiconductor device (such as DRAM or flash memory) having memory cells at a high speed. These have been difficult to achieve a high polishing rate with a method using a conventional polishing liquid for CMP, indicating that one aspect of the polishing liquid according to the present embodiment can achieve a high polishing rate without greatly depending on the uneven shape of the surface to be polished.

[0099] The substrate is not limited to a substrate having only a silicon oxide film on the surface, and may be a substrate further having a silicon nitride film, a polycrystalline silicon film, etc. on the surface in addition to the silicon oxide film. The substrate may be a substrate having an inorganic insulating film such as silicon oxide, glass, or silicon nitride; a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc. on a wiring board having predetermined wiring.

[0100] Hereinafter, as an example of a process including the polishing method according to the present embodiment, a process of forming an ILD film (interlayer insulating film) structure by CMP will be described. FIG. 1 is a schematic cross-sectional view showing a process of polishing the ILD film, and shows a process of forming the ILD film between wirings. FIG. 1(a) is a schematic cross-sectional view showing the substrate before polishing. FIG. 1(b) is a schematic cross-sectional view showing the substrate after polishing.

[0101] As shown in FIG. 1(a), in the substrate 100 before polishing, wiring 20 is formed via an ILD film 10 on a lower substrate (not shown) having a predetermined lower wiring (not shown), 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 on the wiring 20 is higher than the other portions, and thus a step D is generated on the surface of the silicon oxide film 30. The wiring 20 is connected to the lower wiring or the like by a contact plug 40 formed so as to penetrate the ILD film 10.

[0102] In the process of forming the ILD film structure, in order to eliminate the step D, unnecessary portions that partially protrude 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 are in contact, and the surface of the silicon oxide film 30 is polished by this polishing member. More specifically, the polished surface (surface) side of the silicon oxide film 30 is pressed against the polishing member of the polishing platen, and while supplying a polishing liquid between the polished surface and the polishing member, the silicon oxide film 30 is polished by relatively moving both of them. As a result, the step D is eliminated, and finally, as shown in FIG. 1(b), the height of the portion of the wiring 20 on the surface of the silicon oxide film 30 and the height of the other portions become substantially the same, and a substrate 100a having a silicon oxide film 30 (ILD film) with a flat surface is obtained.

[0103] As the polishing apparatus used for polishing, for example, an apparatus including a holder for holding a substrate, a polishing platen to which a polishing pad is attached, and means for supplying a polishing liquid onto the polishing pad can be used. Examples of the polishing apparatus include polishing apparatuses manufactured by Ebara Corporation (model numbers: EPO-111, EPO-222, F-REX200, and F-REX300), polishing apparatuses manufactured by Applied Materials (product names: Mirra3400 and Reflexion), and the like. There is no particular limitation on the constituent material of the polishing pad, and for example, general non-woven fabric, foamed polyurethane, porous fluororesin, or the like can be used. Further, the polishing pad may be subjected to groove processing so that the polishing liquid accumulates.

[0104] As for the polishing conditions, although there is no particular limitation, from the viewpoint of preventing the substrate from protruding, the rotation speed of the polishing platen may be 200 min -1 The following may be applicable. 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, the polishing liquid may be continuously supplied to the polishing pad by a pump or the like. There is no limitation on this supply amount, but the surface of the polishing pad may always be covered with the polishing liquid. After polishing, the substrate may be sufficiently washed in running water, and then the water droplets adhering to the substrate may be removed using a spin dryer or the like and then dried.

[0105] By polishing as described above, unevenness on the surface can be eliminated, and a smooth surface can be obtained over the entire surface of the substrate. Further, 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.

[0106] 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 composed of glass and crystalline materials; end faces of optical fibers; single crystals for optics such as scintillators; single crystals for solid-state lasers; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for magnetic disks; magnetic heads, and the like.

[0107] <Manufacturing method, etc.> The manufacturing method of the component according to this embodiment includes a component manufacturing step of obtaining a component using a substrate (member to be polished) polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the manufacturing method of the component according to this embodiment. The component according to this embodiment is not particularly limited, but may be an electronic component (for example, a semiconductor component such as a semiconductor package), may be a wafer (for example, a semiconductor wafer), or may be a chip (for example, a semiconductor chip). As an aspect of the manufacturing method of the component according to this embodiment, in the manufacturing method of the electronic component according to this embodiment, an electronic component is obtained using a substrate polished by the polishing method according to this embodiment. As an aspect of the manufacturing method of the component according to this embodiment, in the manufacturing method of the semiconductor component according to this embodiment, a semiconductor component (for example, a semiconductor package) is obtained using a substrate polished by the polishing method according to this embodiment. The manufacturing method of the component according to this embodiment may include a polishing step of polishing the substrate by the polishing method according to this embodiment before the component manufacturing step.

[0108] As an aspect of the manufacturing method of the component according to this embodiment, the manufacturing method of the component may include a singulation step of singulating a substrate (member to be polished) polished by the polishing method according to this embodiment. The singulation step may be, for example, a step of dicing a wafer (for example, a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (for example, semiconductor chips). As an aspect of the manufacturing method of the component according to this embodiment, the manufacturing method of the electronic component according to this embodiment may include a step of obtaining an electronic component (for example, a semiconductor component) by singulating a substrate polished by the polishing method according to this embodiment. As an aspect of the manufacturing method of the component according to this embodiment, the manufacturing method of the semiconductor component according to this embodiment may include a step of obtaining a semiconductor component (for example, a semiconductor package) by singulating a substrate polished by the polishing method according to this embodiment.

[0109] The manufacturing method of the component according to this embodiment may include, as an aspect of the component manufacturing process, a connection process of connecting (for example, electrically connecting) a substrate (member to be polished) polished by the polishing method according to this embodiment and another connected body. The connected body connected to the substrate polished by the polishing method according to this embodiment is not particularly limited, and may be a substrate polished by the polishing method according to this embodiment, or may be a connected body different from the substrate polished by the polishing method according to this embodiment. In the connection process, the substrate and the connected body may be directly connected (connected in a state where the substrate and the connected body are in contact), or the substrate and the connected body may be connected via another member (such as a conductive member). The connection process can be performed before the singulation process, after the singulation process, or before and after the singulation process.

[0110] The connection process may be a process of connecting the polished surface of the substrate polished by the polishing method according to this embodiment and the connected body, or may be a process of connecting the connection surface of the substrate polished by the polishing method according to this embodiment and the connection surface of the connected body. The connection surface of the substrate may be the polished surface polished by the polishing method according to this embodiment. By the connection process, a connected body including the substrate and the connected body can be obtained. In the connection process, when the connection surface of the substrate has a metal part, the connected body may be brought into contact with the metal part. In the connection process, when the connection surface of the substrate has a metal part and the connection 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.

[0111] The device according to this embodiment (for example, an electronic device such as a semiconductor device) includes at least one selected from the group consisting of a substrate polished by the polishing method according to this embodiment and the component according to this embodiment.

Examples

[0112] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0113] <Production of cerium oxide powder> 40 kg of cerium carbonate hydrate was divided into 10 alumina containers and each was calcined in air at 830 °C for 2 hours to obtain a total of 20 kg of a yellowish-white powder. The powder was identified by X-ray diffraction, and it was confirmed that the powder contained polycrystalline cerium oxide. When the particle size of the powder obtained by calcination was observed by SEM, it was in the range of 20 to 100 μm. Next, 20 kg of cerium oxide powder was dry-ground using a jet mill to obtain cerium oxide powder. The specific surface area of the cerium oxide powder after grinding was 9.4 m 2 / g. The measurement of the specific surface area was carried out by the BET method.

[0114] <Preparation of slurry> 15.0 kg of the cerium oxide powder obtained above and 84.5 kg of deionized water were placed in a container and mixed. Next, 0.5 kg of 1 M (mol / L, about 6 mass%) acetic acid was added, and then stirred for 10 minutes to obtain a cerium oxide mixture. This cerium oxide mixture was fed into another container over 30 minutes. During that time, ultrasonic irradiation was performed on the cerium oxide mixture in the feeding pipe at an ultrasonic frequency of 400 kHz.

[0115] The above-mentioned cerium oxide mixture that had been fed through ultrasonic irradiation was placed in 4 polyethylene containers of 500 mL, 500 g ± 5 g each. Centrifugation was performed on the cerium oxide mixture in each container for 2 minutes under the condition 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 about 6.0 mass% of cerium oxide particles (abrasive grain A) based on the total mass.

[0116] The above-mentioned cerium oxide mixture that had been fed through ultrasonic irradiation was placed in 4 polyethylene containers of 500 mL, 500 g ± 5 g each. Centrifugation was performed on the cerium oxide mixture in each container for 5 minutes under the condition 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 about 2.0 mass% of cerium oxide particles (abrasive grain B) based on the total mass.

[0117] 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. Regarding this sample, the average particle size of the abrasive grains was measured using a laser diffraction / scattering particle size distribution measuring device (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.

[0118] <Preparation of CMP Polishing Liquid> By mixing the above-mentioned slurry, each additive, and deionized water according to the following procedure, polishing liquids having the compositions shown in the following tables (balance: deionized water) were 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 3 and 8, and abrasive grain B was used in Examples 3 and 8. 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-mentioned slurry. Note that the pH of a 1 mM aqueous solution of acetic acid is less than 5.0.

[0119] Specifically, an additive solution was obtained by dissolving each additive in deionized water. Next, the above-mentioned slurry and the additive solution were mixed in the same amount, and then stirred for 10 minutes to obtain a storage liquid for a concentrated 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 final abrasive grain content of 0.25% by mass of the polishing liquid, and contains 5 times the amount of abrasive grains and additives with respect to the final abrasive grain content of 1.00% by mass of the polishing liquid.

[0120] <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 performed 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.

[0121] Then, by diluting the storage liquid for the polishing liquid 20-fold with deionized water, polishing liquids of the examples except for Examples 6, 9, 10, 31 to 35, and 38, and polishing liquids of the comparative examples were obtained. Further, by diluting the storage liquid for the polishing liquid 5-fold with deionized water, polishing liquids of Examples 6, 9, 10, 31 to 35, and 38 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.

[0122] <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 Measurement device: Product name of Horiba, Ltd.: Model (D-71) Measurement method: After three-point calibration of the pH meter using a phthalate pH standard solution (pH: 4.01), a neutral phosphate pH standard solution (pH: 6.86), and a borate pH standard solution (pH: 9.18) as pH standard solutions, the electrode of the pH meter was placed in the polishing liquid, and after 2 minutes or more had elapsed and it had stabilized, the pH was measured using the above-mentioned measurement device.

[0123] (pH of the 1 mM solution of Additive B1) A 1 mM (millimolar concentration) solution was prepared by dissolving Additive B1 in the table in deionized water. The pH of the solution was measured in the same procedure as the pH of the polishing liquid. The results are shown in each table.

[0124] <Evaluation of Polishing Characteristics> (Preparation of wafers for evaluation) As blank wafers (BKW), a φ200 mm non-patterned wafer having a silicon oxide film (SiO2, initial film thickness: 1000 nm) on the surface and a φ200 mm non-patterned wafer having a silicon nitride film (SiN, initial film thickness: 200 nm) on the surface were prepared.

[0125] As a pattern wafer (PTW), a wafer with a test pattern (model number: Sematech864, manufactured by Advantec Co., Ltd., φ200 mm) of a silicon oxide film (initial film thickness: 600 nm) having an uneven pattern on the surface was prepared. The convex portion (Line portion) has an initial step height of 500 nm with respect to the concave portion (Space portion), and the convex portion is provided with a silicon nitride film (initial film thickness: 140 nm) as a stopper for the silicon oxide film underlayer, assuming evaluation for shallow trench isolation. The pattern wafer has a plurality of 20 mm × 20 mm die units, and each die unit has a plurality of 4 mm × 4 mm unit areas. The pattern wafer has, as a 4 mm × 4 mm unit area, a region having parallel line patterns with a pitch of 100 μm width and a Line / Space (L / S) of 10 μm increments from 10 μm / 90 μm (convex portion density: 10%) to 90 μm / 10 μm (convex portion density: 90%). The pattern wafer has, as a 4 mm × 4 mm unit area, a square convex pattern (convex portion density: 100%) of 4 mm × 4 mm and a square concave pattern (convex portion density: 0%) of 4 mm × 4 mm.

[0126] (Polishing procedure) The above-described evaluation wafer was polished using a polishing apparatus (manufactured by Applied Materials, product name: Mirra3400). The above-described evaluation wafer was set in a holder having a suction pad for mounting the substrate. A polishing pad (K-groove, manufactured by DuPont (Dow), model number: IC-1010) made of porous urethane resin was attached to a polishing platen with a diameter of 500 mm.

[0127] The above-described holder was placed on the polishing pad with the polished surface of the above-described evaluation wafer facing downward. The inner tube pressure, retainer ring pressure, and membrane pressure were set to 14 kPa, 21 kPa, and 14 kPa, respectively.

[0128] Then, while dropping the above-described polishing liquid onto the polishing pad attached to the above-described polishing platen at a flow rate of 200 mL / min, the polishing platen and the evaluation wafer were each rotated for 93 min -1 and 87 min-1 It was rotated to polish the surface to be polished. For the blanket wafer, polishing was performed for 30 seconds. For the pattern wafer, according to the polishing rate evaluated with the blanket wafer, in the range of 20 to 60 seconds, the time during which the silicon nitride film under the silicon oxide film was not exposed at the convex portion in the region of L / S = 20 μm / 80 μm was set as the polishing time, and polishing was performed for that polishing time. Subsequently, after thoroughly washing the evaluation wafer after polishing with pure water using a PVA brush (polyvinyl alcohol brush), it was dried.

[0129] (Evaluation of polishing rate) Using an optical interference film thickness measurement device (manufactured by Nanometrics Japan Co., Ltd., product name: AFT-5100), the film thickness change amount of the film to be polished before and after polishing was measured as follows to obtain the polishing rate. The results are shown in each table.

[0130] For the blanket wafer, the film thickness change amount was measured at a total of 41 measurement points including the center point of the wafer and each point at intervals of 5 mm in the diameter direction from the center point (20 points on both sides with the center point as the boundary). (The measurement point next to the measurement point at 95 mm from the center was set at the location 97 mm from the center). The film thickness change amount at the polishing time of 30 seconds at these 41 points was measured, and the average value was obtained as the polishing rate of the blanket wafer.

[0131] For the pattern wafer, the film thickness change amounts in the convex portions in the region of L / S = 20 μm / 80 μm, the convex portions in the region of L / S = 30 μm / 70 μm, the square convex pattern (convex density: 100%), and the square concave pattern (convex density: 0%) were measured to obtain the polishing rate of the pattern wafer. In the central die unit (20 mm × 20 mm) of the pattern wafer, the film thickness change amount at one central location in a unit area (4 mm × 4 mm) of the target pattern was measured.

[0132]

Table 1

[0133]

Table 2

[0134]

Table 3

[0135]

Table 4

[0136]

Table 5

[0137]

Table 6

[0138]

Table 7

[0139]

Table 8

[0140] Although the magnitude relationship of the polishing rate of silicon oxide of the convex portion (Line portion) in the region of L / S = 20 μm / 80 μm is different from the magnitude relationship of the polishing rate of silicon oxide in the blanket wafer, in all of the examples, while achieving a high polishing rate of silicon oxide in the blanket wafer, it is confirmed that a high polishing rate of silicon oxide of the convex portion (for example, ≧300 nm / min) in the region of L / S = 20 μm / 80 μm is obtained.

[0141] In some of the examples, a sufficiently small polishing rate of silicon nitride (for example, <2.0 nm / min) in the blanket wafer is obtained, and in some cases, an especially small polishing rate of silicon nitride (for example, <1.0 nm / min) is obtained. In all of the examples, a high polishing rate of the convex portions (Line portions) in the region of L / S = 30 μm / 70 μm is obtained. The polishing rate of 0% of the convex portions is an index of the dishing characteristics, and in some of the examples, a sufficiently small polishing rate (for example, ≤ 300 nm / min) is obtained. The polishing rate ratio of 100% of the convex portions / 0% of the convex portions is an index of the planarization efficiency, and in some of the examples, a preferable polishing rate ratio (for example, > 1.0) is obtained.

[0142] The inventor has described in the specification the best mode for carrying out the present disclosure. When those skilled in the art read the above description, similar modified forms may become apparent. The inventor is also fully aware of the implementation of different forms of the present disclosure and the implementation of similar forms to which the essence of the present disclosure is applied. Further, in the present disclosure, as its principle, all modified forms of the contents listed in the specification and any combination of various above elements can be used. All possible arbitrary combinations thereof are included in the present disclosure unless specifically limited in the present specification or clearly negated by the context.

Explanation of Signs

[0143] 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 average particle size of the abrasive grains exceeds 100 nm, The additive comprises: (A) a 4-pyrone compound represented by the following general formula (1); and (B2) a cyclic compound having at least one functional group selected from the group consisting of a carboxy group, a carboxylate group, an amino group, and a hydroxy group, A polishing slurry for CMP, wherein a mass ratio of the content of the component (B2) to the content of the component (A) is 0.1 to 10. 【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 (B2) comprises at least one member selected from the group consisting of aromatic aminocarboxylic acids, quinolinecarboxylic acids, pyridinecarboxylic acids, and salts thereof.

3. 2. The polishing slurry for CMP according to claim 1, wherein the component (B2) comprises at least one member selected from the group consisting of quinaldic acid and its salts.

4. 2. The polishing slurry for CMP according to claim 1, wherein the component (B2) comprises at least one member selected from the group consisting of anthranilic acid and its salts.

5. 2. The polishing slurry for CMP according to claim 1, wherein the component (B2) comprises at least one member selected from the group consisting of picolinic acid and salts thereof.

6. 2. The polishing slurry for CMP according to claim 1, wherein the content of the component (B2) is 0.001 to 5 mass %.

7. The CMP polishing slurry according to claim 1 , wherein the cerium-based particles comprise cerium oxide.

8. 2. The polishing liquid for CMP according to claim 1, wherein the content of the abrasive grains is 0.01 to 10 mass %.

9. 2. The polishing liquid for CMP according to claim 1, wherein the component (A) 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.

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

11. The polishing liquid for CMP according to claim 1 , wherein the additive further comprises a saturated monocarboxylic acid.

12. 12. The polishing liquid for CMP according to claim 11, wherein the content of the saturated monocarboxylic acid is 0.0001 to 5 mass %.

13. 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 12; the first liquid containing the abrasive grains and water; and the second liquid containing at least one of the additives and water.

14. 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 12.

15. The polishing method according to claim 14 , wherein the surface to be polished comprises silicon oxide.

16. 14. 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 13.

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

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