Polishing liquid for CMP, polishing liquid set for CMP, and polishing method

Abstract

A polishing liquid for CMP contains abrasive grains, a nitrogen-containing compound, and water. The abrasive grains include cerium-based particles. The nitrogen-containing compound includes: a compound A1 having a condensed ring (a condensed ring having an aromatic five-membered ring with one nitrogen atom); a compound A2 having a quinoline ring and one hydroxy group bonded to the quinoline ring; a compound A3 having an aromatic ring and a hydroxy group bonded to a nitrogen atom; or a compound A4 having a nitrogen-containing aromatic ring to which at least one selected from the group consisting of a hydroxy group and an amino group is bonded.

Description

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

[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.

[0002] In the field of semiconductor manufacturing, as the performance of VLSI devices improves, it is becoming increasingly difficult to achieve both high integration and high speed through miniaturization technology, which is an extension of conventional technology. Therefore, technologies that enable vertical integration (i.e., multi-layer wiring technology) are being developed while continuing to miniaturize semiconductor elements.

[0003] CMP is one of the most important technologies in the process of manufacturing devices with multi-layered wiring. CMP 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, planarization processing by CMP is essential to ensure the depth of focus in lithography. If the surface of the substrate is uneven, it can cause inconveniences such as making it impossible to focus in the exposure process or making it impossible to form a fine wiring structure satisfactorily. CMP is also used in the device manufacturing process to planarize the surface of a plasma oxide film (BPSG, HDP-SiO ２ The method is also applicable to a process for forming an isolation region (inter-element isolation; STI: shallow trench isolation) by polishing a silicon dioxide film (SiO2, p-TEOS, etc.); a process for forming an ILD film (an interlayer insulating film that electrically insulates metal members (wiring, etc.) in the same layer); and a process for planarizing a plug (e.g., an Al / Cu plug) after embedding a film containing silicon oxide in a metal wiring.

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

[0005] Among the processes to which the above-mentioned CMP technology is applied, the CMP process of an ILD film, in particular, requires the polishing of silicon oxide at a high polishing rate. Therefore, silica-based polishing solutions (polishing solutions using abrasive grains containing silica-based particles) that have a high polishing rate are primarily used in the CMP process of an ILD film (see, for example, Patent Document 2 below). However, with silica-based polishing solutions, it tends to be difficult to control polishing scratches, which are the cause of defects. Furthermore, with the recent trend toward finer interconnects, it is desirable to reduce polishing scratches in the CMP process of an ILD film. However, unlike the CMP process of an insulating film for an isolation region, finishing mirror polishing is generally not performed. Therefore, the use of cerium-based polishing solutions (polishing solutions using abrasive grains containing cerium-based particles), which have fewer polishing scratches than silica-based polishing solutions, has been considered (see, for example, Patent Document 3 below).

[0006] JP 2008-288537, JP 9-316431, JP 10-102038

[0007] However, with a cerium-based polishing liquid, it may be difficult to achieve a high removal rate of silicon oxide, and particularly when polishing a patterned wafer having an uneven pattern composed of convex portions (e.g., line portions) and concave portions (e.g., space portions), it may be difficult to achieve a high removal rate of silicon oxide on the convex portions.

[0008] One aspect of the present disclosure is to provide a CMP polishing liquid that can achieve a high removal rate of silicon oxide from convex portions when polishing a patterned wafer having a concave-convex pattern. Another aspect of the present disclosure is to provide a CMP polishing liquid set for obtaining the CMP polishing liquid. Another aspect of the present disclosure is to provide a polishing method using the CMP polishing liquid.

[0009] In some aspects, the present disclosure relates to the following items [1] to

[17] . [1] A polishing slurry for CMP containing abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains contain cerium-based particles, and the nitrogen-containing compound contains a compound A1 having a fused ring, the fused ring being an aromatic five-membered ring containing one nitrogen atom. [2] The polishing slurry for CMP according to item [1], wherein the compound A1 contains an indole ring. [3] The polishing slurry for CMP according to item [1] or [2], wherein the aromatic five-membered ring is bonded to an alkyl group substituted with at least one group selected from the group consisting of a carboxy group and a carboxylate group. [4] The polishing slurry for CMP according to any one of items [1] to [3], wherein the nitrogen-containing compound contains 1H-indole-3-acetic acid. [5] The polishing slurry for CMP according to any one of items [1] to [4], wherein the nitrogen-containing compound contains N-acetyl-DL-tryptophan. [6] A polishing slurry for CMP containing abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes compound A2 having a quinoline ring and one hydroxy group bonded to the quinoline ring. [7] A polishing slurry for CMP containing abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes compound A3 having an aromatic ring and a hydroxy group bonded to a nitrogen atom. [8] The polishing slurry for CMP according to [7], wherein compound A3 has a benzene ring. [9] The polishing slurry for CMP according to [7] or [8], wherein a hydroxyamide group is bonded to the aromatic ring.

[10] A polishing slurry for CMP containing abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes compound A4 having a nitrogen-containing aromatic ring to which at least one group selected from the group consisting of a hydroxy group and an amino group is bonded.

[11] The polishing slurry for CMP according to

[10] , wherein the compound A4 has a pyridine ring.

[12] The polishing slurry for CMP according to

[10] or

[11] , wherein at least one selected from the group consisting of a carboxy group and a carboxylate group is further bonded to the nitrogen-containing aromatic ring.

[13] The polishing slurry for CMP according to any one of [1] to

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

[14] The polishing slurry for CMP according to any one of [1] to

[13] , wherein the pH is 3.00 to 7.00.

[15] A polishing liquid set for CMP, in which the components contained in the polishing liquid for CMP according to any one of [1] to

[14] are stored separately as a first liquid and a second liquid, the first liquid containing the abrasive grains and water, and the second liquid containing the nitrogen-containing compound and water.

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

[14] .

[17] The polishing method according to

[16] , in which the surface to be polished contains silicon oxide.

[0010] According to one aspect of the present disclosure, there is provided a CMP polishing liquid that can achieve a high removal rate of silicon oxide from convex portions when polishing a patterned wafer having a concave-convex pattern. According to another aspect of the present disclosure, there is provided a CMP polishing liquid set for obtaining the CMP polishing liquid. According to another aspect of the present disclosure, there is provided a polishing method using the CMP polishing liquid.

[0011] 1A to 1C are schematic cross-sectional views showing a process of polishing an ILD film.

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

[0013] In this specification, numerical ranges indicated using "to" indicate a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range exceeding A and A. In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper or lower limit of a numerical range in another stage. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. The term "layer" or "film" encompasses not only a structure formed over the entire surface when observed in a plan view, but also a structure formed on a portion of the surface. The term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. The term "hydroxy group" does not encompass the OH structure contained in a carboxy group.

[0014] <Polishing Slurry for CMP> The polishing slurry for CMP according to this embodiment (including the first to fourth embodiments, hereinafter the same) is a polishing slurry for CMP (hereinafter sometimes simply referred to as "polishing slurry") containing abrasive grains, a nitrogen-containing compound, and water. The abrasive grains include cerium-based particles (particles containing a cerium-based compound). The nitrogen-containing compound of the polishing slurry according to the first embodiment includes a compound A1 having a fused ring, the fused ring having an aromatic five-membered ring with one nitrogen atom. The nitrogen-containing compound of the polishing slurry according to the second embodiment includes a compound A2 having a quinoline ring and one hydroxy group bonded to the quinoline ring. The nitrogen-containing compound of the polishing slurry according to the third embodiment includes a compound A3 having an aromatic ring and a hydroxy group bonded to a nitrogen atom. The nitrogen-containing compound of the polishing slurry according to the fourth embodiment includes a compound A4 having a nitrogen-containing aromatic ring to which at least one group selected from the group consisting of a hydroxy group and an amino group is bonded.

[0015] The polishing liquid according to this embodiment can achieve a high removal rate of silicon oxide from the convex portions when polishing a patterned wafer having a concave-convex pattern composed of convex portions (e.g., line portions) and concave portions (e.g., space portions), and can achieve a high removal rate of silicon oxide from the convex portions when polishing, for example, a region of the patterned wafer where Line / Space (L / S) = 30 μm / 570 μm. The polishing liquid according to this embodiment can achieve a removal rate of silicon oxide from the convex portions in a region where L / S = 30 μm / 570 μm, for example, of 300 nm / min or more (preferably, 400 nm / min or more, 500 nm / min or more, 1000 nm / min or more, 1500 nm / min or more, 2000 nm / min or more, etc.), in the evaluation method described in the Examples below.

[0016] The factors that enable a high removal rate of silicon oxide on convex portions to be achieved in polishing a patterned wafer are not necessarily clear, but are presumed to be as follows. However, the factors are not limited to the following. That is, even if high-speed polishing of silicon oxide on a blanket wafer that does not have a concave-convex pattern is possible by using a polishing liquid containing abrasive grains that include cerium-based particles, it may not be possible to achieve a high removal rate of silicon oxide on convex portions of a patterned wafer. In particular, a peculiar phenomenon may occur in which a high removal rate of silicon oxide on convex portions cannot be achieved in polishing a low-density pattern region, such as one with an L / S ratio of 30 μm / 570 μm, which is likely to be subjected to an effectively high polishing pressure. On the other hand, according to the polishing liquid of this embodiment, by using at least one nitrogen-containing compound A selected from the group consisting of compounds A1, A2, A3, and A4, the ring structure, functional group, and the like of nitrogen-containing compound A enhances the interaction between the polishing liquid and the silicon oxide on the protruding portions (for example, the chemical reaction (reaction resulting from Si—O—Ce bonds) between the cerium-based particles in the polishing liquid and the silicon oxide on the protruding portions is promoted), making it possible to obtain a high polishing rate for the silicon oxide on the protruding portions, and a high polishing rate for the silicon oxide on the protruding portions can be achieved when polishing an area of ​​a patterned wafer where L / S=30 μm / 570 μm.

[0017] The polishing liquid can be used to polish a patterned wafer having a concave-convex pattern, thereby removing the convex portions, thereby planarizing the polished surface. In this case, from the viewpoint of obtaining high flatness or shortening the polishing time required for planarization, it may be necessary to achieve a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer having a concave-convex pattern to silicon oxide on a blanket wafer not having a concave-convex pattern. According to one aspect of the polishing liquid of this embodiment, a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer having a concave-convex pattern to silicon oxide on a blanket wafer not having a concave-convex pattern can be achieved. For example, a high polishing rate ratio of silicon oxide on the convex portions in a line / space (L / S) region of the patterned wafer of 30 μm / 570 μm can be achieved to silicon oxide on the blanket wafer not having a concave-convex pattern. According to one aspect of the polishing liquid of this embodiment, in the evaluation method described in the Examples below, the polishing rate ratio of silicon oxide on the convex portions in the region of L / S=30 μm / 570 μm of the patterned wafer to silicon oxide on the blanket wafer can be, for example, 0.5 or more (preferably, 1.0 or more, 5.0 or more, 10.0 or more, 30.0 or more, etc.) Obtaining a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer having a concave-convex pattern to silicon oxide on a blanket wafer not having a concave-convex pattern can realize a property that allows the convex portions to be selectively polished, thereby realizing high flatness.

[0018] According to one aspect of the polishing liquid of this embodiment, it is possible to achieve high-speed polishing of silicon oxide on a blanket wafer that does not have a concave-convex pattern, while also achieving a high polishing rate for silicon oxide on convex portions when polishing a patterned wafer. According to one aspect of the polishing liquid of this embodiment, it is possible to obtain a polishing rate for silicon oxide on a blanket wafer of, for example, 15 nm / min or more (preferably 50 nm / min or more, 100 nm / min or more, 300 nm / min or more, 500 nm / min or more, 1000 nm / min or more, etc.) in the evaluation method described in the Examples below.

[0019] In the process of forming an isolation region, it may be necessary to suppress the polishing rate of a silicon nitride film used as a stopper underlying a silicon oxide film, and a high polishing selectivity of silicon oxide relative to silicon nitride (polishing rate of silicon oxide / polishing rate of silicon nitride) may be required. According to one aspect of the polishing liquid of this embodiment, a sufficiently low polishing rate of silicon nitride can be obtained, and a high polishing selectivity of silicon oxide relative to silicon nitride can be obtained. This is suitable for polishing when forming an isolation region. According to one aspect of the polishing liquid of this embodiment, in the evaluation method described in the Examples below, a polishing rate of silicon nitride on a blanket wafer of, for example, 150 nm / min or less (preferably 100 nm / min or less, 50 nm / min or less, 10 nm / min or less, 5 nm / min or less, etc.) can be obtained.

[0020] The polishing liquid according to this embodiment can be used in CMP of semiconductor wafer materials, for example, to polish a silicon oxide film formed on the surface of a semiconductor wafer. The polishing liquid according to this embodiment can be used in the CMP process of an ILD film. According to one aspect of the polishing liquid according to this embodiment, a high polishing rate can be achieved, abrasive aggregation and the occurrence of polishing scratches can be suppressed, and high flatness can be obtained.

[0021] (Abrasive grains) In the polishing liquid according to this embodiment, the abrasive grains include cerium-based particles (particles containing a cerium-based compound). By using cerium-based particles as the abrasive grains, it is easy to obtain a high removal rate of silicon oxide on the convex portions of a patterned wafer while reducing polishing scratches on the polished surface.

[0022] Examples of the cerium-based compound of the cerium-based particles include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The cerium-based particles may contain cerium oxide from the viewpoint of easily obtaining a high removal rate of silicon oxide on the convex portions of a patterned wafer (such as convex portions in the region of L / S=30 μm / 570 μm; the same applies hereinafter), or from the viewpoint of easily obtaining a polished surface with few polishing scratches and excellent flatness. The cerium oxide is CeO ２ (cerium (IV) oxide, ceria), and Ce ２ O ３ (cerium(III) oxide).

[0023] The cerium oxide particles (particles containing cerium oxide) may contain polycrystalline cerium oxide having grain boundaries. The particles containing polycrystalline cerium oxide have the property of becoming finer during polishing and simultaneously revealing active surfaces one after another, thereby enabling a high polishing rate of silicon oxide on the convex portions of a patterned wafer to be maintained at a high level.

[0024] Methods for producing cerium oxide particles include a calcination method and an oxidation method using hydrogen peroxide or the like. When calcining, the temperature during calcination may be 350 to 900°C. When the cerium oxide particles are aggregated, the particles may be mechanically pulverized. The pulverization method may be, for example, dry pulverization using a jet mill or the like, or wet pulverization using a planetary bead mill or the like. As the jet mill, for example, the one described in "Chemical Engineering Journal," Vol. 6, No. 5, (1980), pp. 527-532, can be used.

[0025] The zeta potential (surface potential) of the abrasive grains in the polishing solution may be positive (the zeta potential may exceed 0 mV) from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer. The zeta potential of the abrasive grains can be measured, for example, using a dynamic light scattering zeta potential measuring device (e.g., manufactured by Beckman Coulter, Inc., product name: DelsaNano C). The zeta potential of the abrasive grains can be adjusted using an additive. For example, abrasive grains having a positive zeta potential can be obtained by contacting the abrasive grains with an acid component (e.g., acetic acid).

[0026] The average particle size of the abrasive grains may be 50 nm or more, 70 nm or more, 80 nm or more, 100 nm or more, more than 100 nm, 105 nm or more, 110 nm or more, 115 nm or more, 120 nm or more, 125 nm or more, 130 nm or more, 135 nm or more, or 140 nm or more, from the viewpoint of easily obtaining a high removal rate of silicon oxide on the convex portions of the patterned wafer. The average particle size of the abrasive grains may be 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 180 nm or less, 150 nm or less, or 140 nm or less, from the viewpoint of easily suppressing the occurrence of polishing scratches. From these viewpoints, the average particle size of the abrasive grains may be 50 to 500 nm, 50 to 200 nm, 50 to 150 nm, 70 to 500 nm, 70 to 200 nm, 70 to 150 nm, 100 to 500 nm, 100 to 200 nm, or 100 to 150 nm.

[0027] The "average particle size of abrasive grains" refers to the median value of the volume distribution measured by a particle size distribution analyzer (e.g., a laser diffraction / scattering particle size analyzer) for a sample containing dispersed abrasive grains, and can be measured using a Microtrac MT3300EXII (trade name) manufactured by MicrotracBEL Corp. For example, a sample is prepared by dispersing abrasive grains in water so that the content of abrasive grains is adjusted to a range suitable for measurement, and this sample is then placed in the analyzer to measure the average particle size. When measuring the particle size of abrasive grains in a polishing solution, the content of abrasive grains in the polishing solution is adjusted to a range suitable for measurement, and this sample can be used for measurement in a similar manner. By adjusting the average particle size of the abrasive grains, a high polishing rate and low scratch characteristics of silicon oxide corresponding to the particle size of the abrasive grains can be efficiently obtained.

[0028] The content of the abrasive grains may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer. The content of the abrasive grains may be 0.01% by mass or more, 0.05% by mass or more, 0.10% by mass or more, 0.20% by mass or more, 0.30% by mass or more, 0.40% by mass or more, 0.50% by mass or more, 0.60% by mass or more, 0.70% by mass or more, 0.80% by mass or more, 0.90% by mass or more, or 1.0% by mass or more. From the viewpoint of easily achieving excellent dispersion stability of the abrasive grains, the content of the abrasive grains may be 20% by mass or less, 15% by mass or less, 12% by mass or less, 10% by mass or less, 8.0% by mass or less, 6.0% by mass or less, 5.0% by mass or less, 4.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, 1.5% by mass or less, or 1.0% by mass or less. From these viewpoints, the content of the abrasive grains may be 0.01 to 20 mass%, 0.01 to 10 mass%, 0.01 to 5.0 mass%, 0.10 to 20 mass%, 0.10 to 10 mass%, 0.10 to 5.0 mass%, 0.50 to 20 mass%, 0.50 to 10 mass%, or 0.50 to 5.0 mass%.

[0029] (Nitrogen-Containing Compound) The nitrogen-containing compound in the polishing liquid according to this embodiment includes at least one nitrogen-containing compound A selected from the group consisting of compound A1, compound A2, compound A3, and compound A4. The nitrogen-containing compound in the polishing liquid according to this embodiment may include nitrogen-containing compound A and a nitrogen-containing compound other than nitrogen-containing compound A.

[0030] The nitrogen-containing compound of the polishing liquid according to the first embodiment includes a compound A1 having a fused ring C1, and the fused ring C1 has an aromatic five-membered ring containing one nitrogen atom (hereinafter referred to as a "five-membered ring C11"). The five-membered ring C11 has one nitrogen atom (the nitrogen atom constituting the five-membered ring C11). Examples of the five-membered ring C11 include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, and an isothiazole ring. The fused ring C1 may have a pyrrole ring as the five-membered ring C11, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer.

[0031] The fused ring C1 has a 5-membered ring C11 and another ring C12. The ring C12 may be an aromatic ring, a non-aromatic ring (such as an alicyclic ring), a heterocyclic ring, or a non-heterocyclic ring. From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, compound A1 may have a fused ring having a 5-membered ring C11 and an aromatic ring, a fused ring having a 5-membered ring C11 and a non-heterocyclic ring, or a fused ring having a 5-membered ring C11 and a benzene ring. From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, the fused ring C1 may be a fused ring consisting of a 5-membered ring C11 and another ring C12.

[0032] Compound A1 may have an indole ring as fused ring C1, from the viewpoint of easily achieving a high polishing rate for silicon oxide on convex portions of a patterned wafer. Compound A1 may have a ring other than fused ring C1, but does not need to have a ring other than fused ring C1, from the viewpoint of easily achieving a high polishing rate for silicon oxide on convex portions of a patterned wafer.

[0033] Compound A1 may have, in addition to the nitrogen atom of the five-membered ring C11, a nitrogen atom that does not constitute the five-membered ring C11, or a nitrogen atom that does not constitute a ring. The number of nitrogen atoms in compound A1 may be 1 or 2, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer.

[0034] A substituent may be bonded to the fused ring C1. The substituent may be bonded to the 5-membered ring C11 or to the ring C12. Examples of the substituent include substituted or unsubstituted alkyl groups, hydroxy groups, carboxy groups, carboxylate groups, aldehyde groups, alkoxy groups, ester groups, substituted or unsubstituted amino groups, amide groups (excluding hydroxyamide groups), hydroxyamide groups, nitro groups, cyano groups, mercapto groups, and halogeno groups (fluoro groups, chloro groups, bromo groups, iodo groups, etc.). The number of carbon atoms in the alkyl group (excluding the number of carbon atoms in the substituent) may be 1, 2, or 3 from the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, or easily achieving high polishing selectivity of silicon oxide to silicon nitride, and may be 1 or 2 from the viewpoint of easily achieving excellent dispersion stability of abrasive grains.

[0035] From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, easily achieving a high polishing rate ratio for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or easily achieving high polishing selectivity for silicon oxide relative to silicon nitride, at least one group selected from the group consisting of a substituted or unsubstituted alkyl group, a hydroxy group, a carboxy group, a carboxylate group, and an alkoxy group may be bonded to the fused ring C1, or an alkyl group substituted with at least one group selected from the group consisting of a carboxy group, a carboxylate group, an alkoxy group, an ester group, and an amino group (unsubstituted amino group, acetylamino group, etc.) may be bonded to the fused ring C1.

[0036] From the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, or easily achieving high polishing selectivity of silicon oxide to silicon nitride, at least one selected from the group consisting of a substituted or unsubstituted alkyl group, a carboxy group, and a carboxylate group may be bonded to the five-membered ring C11, an alkyl group substituted with at least one selected from the group consisting of a carboxy group, a carboxylate group, an alkoxy group, an ester group, and an amino group (e.g., an unsubstituted amino group, an acetylamino group), or an alkyl group substituted with at least one selected from the group consisting of a carboxy group and a carboxylate group may be bonded to the five-membered ring C11. From the viewpoint of easily achieving excellent dispersion stability of the abrasive grains, an alkyl group substituted with at least one selected from the group consisting of a carboxy group, a carboxylate group, an ester group, and an amino group (e.g., an unsubstituted amino group, an acetylamino group) may be bonded to the five-membered ring C11.

[0037] The substituent bonded to the five-membered ring C11 may be bonded to an atom (e.g., a carbon atom) at the third position relative to the nitrogen atom in the five-membered ring C11 (e.g., a pyrrole ring), from the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer. From the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, at least one group selected from the group consisting of a hydroxy group and an alkoxy group may be bonded to ring C12. From the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, ring C12 may be unsubstituted.

[0038] From the viewpoint of readily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer, the nitrogen-containing compound of the polishing liquid according to the first embodiment may contain, as compound A1, at least one selected from the group consisting of 1H-indole-3-carboxylic acid, 1H-indole-3-acetic acid, 1H-indole-3-propionic acid, methyl 1H-indole-3-acetate, 3-methoxymethylindole, N-acetyl-DL-tryptophan, 5-hydroxy-L-tryptophan, 5-hydroxyindole-3-acetic acid, and 5-methoxyindole-3-acetic acid, and may contain 1H-indole-3-acetic acid and N-acetyl-DL-tryptophan.

[0039] The nitrogen-containing compound of the polishing liquid according to the second embodiment includes compound A2 having a quinoline ring and one hydroxy group bonded to the quinoline ring. Compound A2 has one hydroxy group directly bonded to the quinoline ring. In compound A2, the number of hydroxy groups bonded to the quinoline ring is one. Compound A2 may have a hydroxy group that is not bonded to the quinoline ring, but does not need to have a hydroxy group that is not bonded to the quinoline ring, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer.

[0040] The hydroxy group bonded to the quinoline ring may be bonded to the carbon atom at the 8th position relative to the nitrogen atom in the quinoline ring, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer.

[0041] From the viewpoint of easily obtaining a high removal rate of silicon oxide on the convex portions of a patterned wafer, the number of nitrogen atoms in compound A2 may be 1. Compound A2 may have nitrogen atoms other than the nitrogen atoms constituting the quinoline ring, but from the viewpoint of easily obtaining a high removal rate of silicon oxide on the convex portions of a patterned wafer, it is not necessary for compound A2 to have nitrogen atoms other than the nitrogen atoms constituting the quinoline ring.

[0042] A substituent other than a hydroxy group may be bonded to the quinoline ring. Examples of the substituent include a substituted or unsubstituted alkyl group, a carboxy group, a carboxylate group, an aldehyde group, an alkoxy group, an ester group, a substituted or unsubstituted amino group, an amide group (excluding a hydroxyamide group), a hydroxyamide group, a nitro group, a cyano group, a mercapto group, and a halogeno group (such as a fluoro group, a chloro group, a bromo group, or an iodo group). From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, a substituent other than a hydroxy group does not need to be bonded to the quinoline ring.

[0043] The nitrogen-containing compound of the polishing liquid according to the second embodiment may contain 8-hydroxyquinoline as compound A2, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer.

[0044] The nitrogen-containing compound in the polishing liquid according to the third embodiment includes a compound A3 having an aromatic ring and a hydroxy group bonded to a nitrogen atom. Compound A3 has a hydroxy group directly bonded to the nitrogen atom.

[0045] The nitrogen atom having a hydroxy group bonded thereto may be directly bonded to an aromatic ring, but does not have to be directly bonded to an aromatic ring, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer. The nitrogen atom having a hydroxy group bonded thereto may be a nitrogen atom constituting a ring, but from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, it may be a nitrogen atom not constituting a ring.

[0046] Compound A3 may have an aromatic ring that constitutes a fused ring, but from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, it may have a monocyclic aromatic ring (aromatic ring that does not constitute a fused ring). Compound A3 may have a heterocycle as the aromatic ring, but from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, it may have a non-heterocycle or a benzene ring.

[0047] The number of aromatic rings or the number of benzene rings in compound A3 may be 1, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer. For example, when compound A3 has a fused ring formed by two aromatic rings, the number of aromatic rings is 2 (the same applies to the number of benzene rings). The number of nitrogen atoms in compound A3 may be 1, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer.

[0048] The number of hydroxy groups in compound A3 may be 1 or 2, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer; it may be 1, from the viewpoint of easily achieving an even higher polishing rate for silicon oxide on the convex portions of a patterned wafer; and it may be 2, from the viewpoint of easily achieving a high polishing rate ratio for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or from the viewpoint of easily achieving a high polishing selectivity for silicon oxide over silicon nitride. In compound A3, the number of hydroxy groups bonded to nitrogen atoms may be 1, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer. Compound A3 does not need to have a hydroxy group not bonded to a nitrogen atom, from the viewpoint of easily achieving a high polishing rate ratio for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or from the viewpoint of easily achieving a high polishing selectivity for silicon oxide over silicon nitride. In addition to a hydroxy group bonded to a nitrogen atom, compound A3 may have a hydroxy group not bonded to a nitrogen atom (for example, a hydroxy group bonded to an aromatic ring), from the viewpoint of easily achieving a high polishing rate ratio for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or from the viewpoint of easily achieving a high polishing selectivity for silicon oxide over silicon nitride.

[0049] A substituent may be bonded to the aromatic ring. Examples of the substituent include a substituted or unsubstituted alkyl group, a hydroxy group, a carboxy group, a carboxylate group, an aldehyde group, an alkoxy group, an ester group, a substituted or unsubstituted amino group, an amide group (excluding a hydroxyamide group), a hydroxyamide group, a nitro group, a cyano group, a mercapto group, and a halogeno group (such as a fluoro group, a chloro group, a bromo group, or an iodo group). A hydroxyamide group may be bonded to the aromatic ring from the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer. A hydroxy group may be bonded to the aromatic ring from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or from the viewpoint of easily achieving a high polishing selectivity of silicon oxide over silicon nitride.

[0050] The nitrogen-containing compound of the polishing liquid according to the third embodiment may contain, as compound A3, at least one selected from the group consisting of benzohydroxamic acid and salicylaldoxime, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer; may contain benzohydroxamic acid, from the viewpoint of easily achieving an even higher removal rate of silicon oxide on the convex portions of a patterned wafer; and may contain salicylaldoxime, from the viewpoint of easily achieving a high removal rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, or from the viewpoint of easily achieving high polishing selectivity of silicon oxide over silicon nitride.

[0051] The nitrogen-containing compound of the polishing liquid according to the fourth embodiment includes compound A4 having a nitrogen-containing aromatic ring C4 to which at least one group selected from the group consisting of a hydroxy group and an amino group is bonded. Compound A4 has at least one group selected from the group consisting of a hydroxy group and an amino group as a substituent directly bonded to the nitrogen-containing aromatic ring C4. In a compound having a fused ring formed by a nitrogen-containing aromatic ring X1 and a ring X2 that does not correspond to a nitrogen-containing aromatic ring, if a hydroxy group and an amino group are not bonded to the nitrogen-containing aromatic ring X1 and at least one group selected from the group consisting of a hydroxy group and an amino group is bonded to ring X2, such a compound does not correspond to compound A4.

[0052] At least one selected from the group consisting of a hydroxy group and an amino group may be bonded to at least one selected from the group consisting of an atom at the 3-position (e.g., a carbon atom) and an atom at the 5-position (e.g., a carbon atom) of the nitrogen atom in the nitrogen-containing aromatic ring C4, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer, or may be bonded to an atom at the 3-position (e.g., a carbon atom) of the nitrogen atom in the nitrogen-containing aromatic ring C4, from the viewpoint of easily achieving an even higher polishing rate for silicon oxide on the convex portions of a patterned wafer or from the viewpoint of easily achieving high polishing selectivity for silicon oxide over silicon nitride.

[0053] Examples of the nitrogen-containing aromatic ring C4 include 6-membered rings such as a pyridine ring, pyridazine ring, pyrimidine ring, and pyrazine ring; and 5-membered rings such as a pyrrole ring, pyrazole ring, imidazole ring, triazole ring, and tetrazole ring. From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, compound A4 may have a 6-membered ring or a pyridine ring as the nitrogen-containing aromatic ring C4. Compound A4 may have a nitrogen-containing aromatic ring that forms a fused ring as the nitrogen-containing aromatic ring C4, but from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, compound A4 may have a monocyclic nitrogen-containing aromatic ring (a nitrogen-containing aromatic ring that does not form a fused ring). From the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, the number of nitrogen-containing aromatic rings C4 in compound A4 may be 1.

[0054] Compound A4 may have a hydroxy group that is not bonded to a nitrogen-containing aromatic ring, or may have an amino group that is not bonded to a nitrogen-containing aromatic ring; however, from the viewpoint of easily achieving a high removal rate of silicon oxide on convex portions of a patterned wafer, compound A4 does not need to have a hydroxy group that is not bonded to a nitrogen-containing aromatic ring, does not need to have an amino group that is not bonded to a nitrogen-containing aromatic ring, and does not need to have a hydroxy group or amino group that is not bonded to a nitrogen-containing aromatic ring.

[0055] In compound A4, the number of hydroxy groups (the total of hydroxy groups bonded to the nitrogen-containing aromatic ring and hydroxy groups not bonded to the nitrogen-containing aromatic ring) may be 1, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer. In compound A4, the number of hydroxy groups bonded to the nitrogen-containing aromatic ring may be 1, from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer.

[0056] From the viewpoint of easily achieving a high polishing rate for silicon oxide on convex portions of a patterned wafer, the number of amino groups in compound A4 (the total of amino groups bonded to nitrogen-containing aromatic rings and amino groups not bonded to nitrogen-containing aromatic rings) may be 1. From the viewpoint of easily achieving a high polishing rate for silicon oxide on convex portions of a patterned wafer, the number of amino groups bonded to nitrogen-containing aromatic rings in compound A4 may be 1.

[0057] The number of nitrogen atoms in compound A4 may be 1 or 2 from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer, 1 from the viewpoint of easily achieving a high polishing rate ratio for silicon oxide on the convex portions of a patterned wafer relative to silicon oxide on a blanket wafer or easily achieving high polishing selectivity for silicon oxide over silicon nitride, and 2 from the viewpoint of easily achieving an even higher polishing rate for silicon oxide on the convex portions of a patterned wafer. The number of nitrogen atoms in nitrogen-containing aromatic ring C4 (nitrogen atoms constituting the nitrogen aromatic ring) may be 1 from the viewpoint of easily achieving a high polishing rate for silicon oxide on the convex portions of a patterned wafer.

[0058] A substituent other than a hydroxy group and an amino group may be bonded to the nitrogen-containing aromatic ring C4. Examples of the substituent include a substituted or unsubstituted alkyl group, a carboxy group, a carboxylate salt group, an aldehyde group, an alkoxy group, an ester group, an amide group (excluding a hydroxyamide group), a hydroxyamide group, a nitro group, a cyano group, a mercapto group, and a halogeno group (such as a fluoro group, a chloro group, a bromo group, or an iodo group). From the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, at least one selected from the group consisting of a carboxy group and a carboxylate salt group may be bonded to the nitrogen-containing aromatic ring C4, and at least one selected from the group consisting of a carboxy group and a carboxylate salt group may be bonded to an atom (e.g., a carbon atom) at the second position relative to the nitrogen atom in the nitrogen-containing aromatic ring C4.

[0059] From the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer, the nitrogen-containing compound of the polishing liquid according to the fourth embodiment may contain, as compound A4, at least one selected from the group consisting of 3-hydroxy-2-pyridinecarboxylic acid, 5-hydroxy-2-pyridinecarboxylic acid, and 5-amino-2-pyridinecarboxylic acid, and may contain 5-hydroxy-2-pyridinecarboxylic acid.

[0060] From the viewpoint of easily obtaining a high removal rate of silicon oxide on the convex portions of a patterned wafer, the content of nitrogen-containing compound A, the content of compound A1, the content of compound A2, the content of compound A3, or the content of compound A4 may be 50 mass% or more, 70 mass% or more, 90 mass% or more, 95 mass% or more, 97 mass% or more, 98 mass% or more, or 99 mass% or more based on the total amount of nitrogen-containing compounds (total amount of nitrogen-containing compounds contained in the polishing liquid). The nitrogen-containing compounds contained in the polishing liquid may be essentially composed of nitrogen-containing compound A, compound A1, compound A2, compound A3, or compound A4 (an embodiment in which essentially 100 mass% of the nitrogen-containing compounds contained in the polishing liquid are nitrogen-containing compound A, compound A1, compound A2, compound A3, or compound A4).

[0061] The content of nitrogen-containing compound A, compound A1, compound A2, compound A3, or compound A4 may be in the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer. The content A may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, or 0.10 mass% or more. The content A may be 10 mass% or less, 8.0 mass% or less, 5.0 mass% or less, 3.0 mass% or less, 1.0 mass% or less, 0.80 mass% or less, 0.50 mass% or less, 0.30 mass% or less, 0.20 mass% or less, or 0.10 mass% or less. From these viewpoints, the content A may be 0.001 to 10 mass%, 0.001 to 1.0 mass%, 0.001 to 0.50 mass%, 0.01 to 10 mass%, 0.01 to 1.0 mass%, 0.01 to 0.50 mass%, 0.05 to 10 mass%, 0.05 to 1.0 mass%, or 0.05 to 0.50 mass%.

[0062] The mass ratio B of the nitrogen-containing compound A to the abrasive grain content (nitrogen-containing compound A / abrasive grains), the mass ratio of compound A1 to the abrasive grain content (compound A1 / abrasive grains), the mass ratio of compound A2 to the abrasive grain content (compound A2 / abrasive grains), the mass ratio of compound A3 to the abrasive grain content (compound A3 / abrasive grains), or the mass ratio of compound A4 to the abrasive grain content (compound A4 / abrasive grains) may be within the following ranges, from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer. Mass ratio B may be 0.001 or more, 0.005 or more, 0.01 or more, 0.03 or more, 0.05 or more, 0.08 or more, or 0.10 or more. The mass ratio B may be 10 or less, 8.0 or less, 5.0 or less, 3.0 or less, 1.0 or less, 0.80 or less, 0.50 or less, 0.30 or less, 0.20 or less, or 0.10 or less. From these viewpoints, the mass ratio B may be 0.001 to 10, 0.001 to 1.0, 0.001 to 0.50, 0.01 to 10, 0.01 to 1.0, 0.01 to 0.50, 0.05 to 10, 0.05 to 1.0, or 0.05 to 0.50.

[0063] The polishing liquid according to this embodiment may contain a nonionic polymer. Examples of the nonionic polymer include ether surfactants such as polyglycerin, polyglycerin fatty acid esters, polyglycerin derivatives, polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene lauryl ether, polyoxypropylene polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene ether derivatives, polyoxypropylene glyceryl ether, polyethylene glycol, methoxypolyethylene glycol, and oxyethylene adducts of acetylene diols; ester surfactants such as sorbitan fatty acid esters and glycerol borate fatty acid esters; aminoether surfactants such as polyoxyethylene alkylamines; ether ester surfactants such as polyoxyethylene glycerol borate fatty acid esters and polyoxyethylene alkyl esters; alkanolamide surfactants such as fatty acid alkanolamides and polyoxyethylene fatty acid alkanolamides; polyvinylpyrrolidone; nonionic polyacrylamide; and nonionic polydimethylacrylamide. From the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer, the nonionic polymer may contain at least one selected from the group consisting of ether type surfactants, ester type surfactants, amino ether type surfactants, ether ester type surfactants, alkanolamide type surfactants, polyvinylpyrrolidone, nonionic polyacrylamide, and nonionic polydimethylacrylamide, and may also contain polyglycerin.

[0064] From the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer, the content of the nonionic polymer may be within the following ranges based on the total mass of the polishing liquid: 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, 0.10 mass% or more, 0.15 mass% or more, or 0.20 mass% or more; 5.00 mass% or less, 3.00 mass% or less, 1.00 mass% or less, 0.80 mass% or less, 0.50 mass% or less, 0.30 mass% or less, or 0.20 mass% or less. From these viewpoints, the content of the nonionic polymer may be 0.01 to 5.00 mass%, 0.01 to 1.00 mass%, 0.01 to 0.50 mass%, 0.05 to 5.00 mass%, 0.05 to 1.00 mass%, 0.05 to 0.50 mass%, 0.10 to 5.00 mass%, 0.10 to 1.00 mass%, or 0.10 to 0.50 mass%.

[0065] The polishing liquid according to this embodiment may contain an acyclic alcohol. The acyclic alcohol is an alcohol that does not have a cyclic structure. Use of the acyclic alcohol makes it easier to improve the dispersion stability of the abrasive grains in the polishing liquid.

[0066] Examples of acyclic alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 1,3-butanediol, 1,4-butanediol, 2-ethylhexanol, 3-methoxy-3-methyl-1-butanol, butyl cellosolve (2-butoxyethanol), butyl carbitol (diethylene glycol mono-n-butyl ether), dipropylene glycol monomethyl ether, ethyl cellosolve (2-ethoxyethanol), methyl carbitol (diethylene glycol monomethyl ether), ethyl carbitol (diethylene glycol monoethyl ether), 1-methoxy-2-propanol, 1-butoxy-2-propanol, tert-butyl cellosolve, etc. The acyclic alcohol may contain 3-methoxy-3-methyl-1-butanol from the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer or easily achieving excellent dispersion stability of abrasive grains.

[0067] From the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of the patterned wafer or easily achieving excellent dispersion stability of the abrasive grains, the content of the acyclic alcohol may be within the following ranges based on the total mass of the polishing liquid. The content of the acyclic alcohol may be 0.01 mass% or more, 0.05 mass% or more, 0.10 mass% or more, 0.50 mass% or more, 1.0 mass% or more, 1.2 mass% or more, 1.4 mass% or more, 1.5 mass% or more, 2.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, or 8.0 mass% or more. The content of the acyclic alcohol may be 50 mass% or less, 30 mass% or less, 20 mass% or less, 10 mass% or less, 9.0 mass% or less, 8.0 mass% or less, 5.0 mass% or less, 3.0 mass% or less, 2.0 mass% or less, 1.5 mass% or less, or 1.4 mass% or less. From these viewpoints, the content of the acyclic alcohol may be 0.01 to 50 mass%, 0.01 to 10 mass%, 0.01 to 5.0 mass%, 0.10 to 50 mass%, 0.10 to 10 mass%, 0.10 to 5.0 mass%, 1.0 to 50 mass%, 1.0 to 10 mass%, 1.0 to 5.0 mass%, 5.0 to 50 mass%, or 5.0 to 10 mass%.

[0068] (Other Additives) The polishing liquid according to this embodiment may contain other components (components other than those described above) according to desired properties. Examples of such components include cationic compounds and pH adjusters, which will be described later.

[0069] The polishing liquid according to this embodiment may contain a compound a having a molecular weight of 100,000 or less and four or more hydroxy groups, or may not contain compound a. The content of compound a may be 0.01 mass% or less, less than 0.01 mass%, 0.001 mass% or less, 0.0001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid. The polishing liquid according to this embodiment may contain a compound b having four or more amino groups, or may not contain compound b. The content of compound b may be 0.001 mass% or less, less than 0.001 mass%, 0.0001 mass% or less, 0.00001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid. The mass ratio of the content of compound a to the content of compound b (compound a / compound b) may be 0.10 or less, or less than 0.10.

[0070] (Water) The water is not particularly limited, but may include at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0071] (pH) From the viewpoint of easily achieving a high removal rate of silicon oxide on the convex portions of a patterned wafer or easily achieving excellent dispersion stability of the abrasive grains, the pH of the polishing liquid according to this embodiment may be in the following ranges: 12.00 or less, 11.00 or less, 10.50 or less, 10.00 or less, less than 10.00, 9.50 or less, 9.00 or less, less than 9.00, 8.50 or less, 8.00 or less, less than 8.00, 7.50 or less, 7.00 or less, less than 7.00, 6.50 or less, 6.00 or less, less than 6.00, 5.50 or less, 5.00 or less, less than 5.00, 4.50 or less, 4.30 or less, 4.20 or less, 4.00 or less, less than 4.00, 3.70 or less, 3.65 or less, 3.60 or less, 3.50 or less, or 3.30 or less. The pH may be 2.00 or more, more than 2.00, 2.50 or more, 3.00 or more, more than 3.00, 3.30 or more, 3.50 or more, 3.60 or more, 3.65 or more, 3.70 or more, 4.00 or more, more than 4.00, 4.20 or more, 4.30 or more, 4.50 or more, 5.00 or more, more than 5.00, 5.50 or more, 6.00 or more, or more than 6.00. From these viewpoints, the pH may be 2.00 to 12.00, 2.00 to 7.00, 2.00 to 5.00, 3.00 to 12.00, 3.00 to 7.00, 3.00 to 5.00, 4.00 to 12.00, 4.00 to 7.00, or 4.00 to 5.00. The pH can be measured by the method described in the Examples.

[0072] Since the pH may vary depending on the type of compound used as an additive, a pH adjuster may be used to adjust the pH to the above range.The pH adjuster is not particularly limited, and examples thereof include acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; and bases such as sodium hydroxide, ammonia (e.g., ammonia water), potassium hydroxide, and calcium hydroxide.The above-mentioned components, such as nitrogen-containing compounds, may be used to adjust the pH.From the viewpoint of improving productivity, the polishing liquid may be prepared without using a pH adjuster, and this polishing liquid may be directly applied to CMP.

[0073] <Method of 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, such as a polishing liquid set for CMP), and the preparation method and usage method differ depending on the type. The (a) normal type is a polishing liquid that can be used as is during polishing without pretreatment such as dilution. The (b) concentrated type is a polishing liquid in which the components are concentrated compared to the (a) normal type, taking into consideration convenience in storage or transportation. The (c) multi-liquid type is a polishing liquid in which the components are separated into multiple liquids (for example, a first liquid containing certain components and a second liquid containing other components) during storage or transportation, and these liquids are mixed when used.

[0074] (a) The normal type can be obtained by dissolving or dispersing abrasive grains and additives in water, which is the main dispersion medium. The polishing liquid can be prepared using, for example, a stirrer, homogenizer, ultrasonic disperser, wet ball mill, etc. The abrasive grains may be micronized during the preparation process of the polishing liquid so that the average particle size of the abrasive grains falls within the desired range. The micronization 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 includes a step of forcibly settling a slurry containing abrasive grains using a centrifuge and a step of extracting only the supernatant liquid. On the other hand, the method using a high-pressure homogenizer involves colliding abrasive grains in a dispersion medium with each other at high pressure.

[0075] The (b) concentrated type is diluted with water immediately before use to achieve the desired component content. After dilution, stirring may be carried out for any length of time until the liquid properties (pH, abrasive grain size, etc.) and polishing properties (silicon oxide polishing rate, polishing selectivity between silicon oxide and silicon nitride, etc.) are comparable to those of the (a) regular type. Since the volume of such a (b) concentrated type decreases depending on the degree of concentration, storage and transportation costs can be reduced.

[0076] The concentration ratio may be 1.5 times or more, 2 times or more, 3 times or more, or 5 times or more. A concentration ratio of 1.5 times or more tends to provide advantages in terms of storage and transportation compared to a concentration ratio of less than 1.5 times. The concentration ratio may be 40 times or less, 20 times or less, or 15 times or less. A concentration ratio of 40 times or less tends to suppress agglomeration of abrasive grains more easily compared to a concentration ratio of more than 40 times.

[0077] The (c) multiple-liquid type has the advantage over the (b) concentrated type that by appropriately separating each liquid (first liquid, second liquid, etc.), it is possible to avoid abrasive aggregation, etc. The components contained in each liquid are arbitrary. The (c) multiple-liquid type (CMP polishing liquid set) is a polishing liquid set for obtaining a polishing liquid by mixing a first liquid (slurry) and a second liquid (additive liquid). For example, in the (c) multiple-liquid type, the components contained in the CMP polishing liquid are stored separately as a first liquid and a second liquid, the first liquid contains abrasive grains and water, and the second liquid contains a nitrogen-containing compound (a nitrogen-containing compound including nitrogen-containing compound A) and water. The first liquid and the second liquid may contain other components as needed. In this case, to improve the dispersibility of abrasive grains in the first liquid, an optional acid or alkali may be added to the first liquid to adjust the pH.

[0078] (c) A multi-liquid type polishing liquid is useful when the combination of components tends to deteriorate in polishing properties in a relatively short time when mixed due to agglomeration of abrasive grains, etc. From the viewpoint of reducing storage and transportation costs, at least one of the liquids (first liquid, second liquid, etc.) may be a concentrated type. In this case, when using the polishing liquid, each liquid and water can be mixed. The concentration ratio and pH of each liquid are arbitrary, as long as the final mixture has liquid properties and polishing properties comparable to those of the (a) normal type polishing liquid.

[0079] <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 polishing liquid set described above. 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 polishing liquid set described above. The surface to be polished may contain silicon oxide, may contain silicon nitride, or may contain silicon oxide and silicon nitride.

[0080] In the polishing method according to this embodiment, the polished surface may have a concave-convex pattern composed of convex portions (line portions) and concave portions (space portions), and the convex portions may contain silicon oxide. The width of the convex portions in the concave-convex pattern may be 50 μm or less, 40 μm or less, or 30 μm or less. The width of the convex portions in the concave-convex pattern may be 10 μm or more, 20 μm or more, or 30 μm or more. The sum of the width of the convex portions and the width of the concave portions in the concave-convex pattern may be 800 μm or less, 700 μm or less, or 600 μm or less. The sum of the width of the convex portions and the width of the concave portions in the concave-convex pattern may be 400 μm or more, 500 μm or more, or 600 μm or more.

[0081] The polishing method according to this 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 discrete semiconductors such as diodes, transistors, compound semiconductors, thermistors, varistors, and thyristors; memory elements such as DRAM (dynamic random access memory), SRAM (static random access memory), EPROM (erasable programmable read-only memory), mask ROM (mask read-only memory), EEPROM (electrically erasable programmable read-only memory), and flash memory; logic circuit elements such as microprocessors, DSPs, and ASICs; integrated circuit elements such as compound semiconductors, typified by MMICs (monolithic microwave integrated circuits); hybrid integrated circuits (hybrid ICs); light-emitting diodes; and photoelectric conversion elements such as charge-coupled devices.

[0082] The substrate is not limited to a substrate having only a silicon oxide film on its surface, but may also be a substrate having, on its surface, in addition to a silicon oxide film, a silicon nitride film, a polycrystalline silicon film, etc. The substrate may be a substrate having, on a wiring board having predetermined wiring, an inorganic insulating film such as silicon oxide, glass, or silicon nitride; or a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc.

[0083] As an example of a process including the polishing method according to this embodiment, a process for forming an ILD (interlayer dielectric) film structure by CMP will be described below. Figure 1 is a schematic cross-sectional view showing the process of polishing an ILD film, illustrating the process of forming an ILD film between wirings. Figure 1(a) is a schematic cross-sectional view showing a substrate before polishing. Figure 1(b) is a schematic cross-sectional view showing the substrate after polishing.

[0084] 1( a), in a substrate 100 before polishing, a wiring 20 is formed on a lower substrate (not shown) having a predetermined lower wiring (not shown) via an ILD film 10, and a silicon oxide film 30 is formed to cover the wiring 20. Because the silicon oxide film 30 is formed on the ILD film 10 on which the wiring 20 is formed, the portion above the wiring 20 is higher than the other portions, resulting in a step D on the surface of the silicon oxide film 30. The wiring 20 is connected to the lower wiring, etc., by a contact plug 40 formed to penetrate the ILD film 10.

[0085] In the process of forming the ILD film structure, in order to eliminate the step D, protruding unnecessary portions 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 abuts against the polishing member, and the surface of the silicon oxide film 30 is polished with the polishing member. More specifically, the surface to be polished (front surface) of the silicon oxide film 30 is pressed against the polishing member of a polishing table, and the surface to be polished and the polishing member are moved relative to each other while a polishing liquid is supplied between them, thereby polishing the silicon oxide film 30. This eliminates the step D, and ultimately, as shown in FIG. 1( b), the height of the wiring 20 portion and the height of the other portions on the surface of the silicon oxide film 30 become approximately the same, resulting in a substrate 100a having a silicon oxide film 30 (ILD film) with a flat surface.

[0086] The polishing apparatus used for polishing may be, for example, an apparatus equipped with a holder for holding the substrate, a polishing platen to which a polishing pad is attached, and a means for supplying a polishing liquid onto the polishing pad. Examples of the polishing apparatus include polishing apparatuses manufactured by Ebara Corporation (model numbers: EPO-111, EPO-222, F-REX200, and F-REX300), and polishing apparatuses manufactured by Applied Materials (product names: Mirra 3400 and Reflexion). The material constituting the polishing pad is not particularly limited, and examples include general nonwoven fabric, polyurethane foam, and porous fluororesin. Furthermore, the polishing pad may be grooved to allow the polishing liquid to accumulate.

[0087] There are no particular restrictions on the polishing conditions, but in order to prevent the substrate from protruding, the rotation speed of the polishing platen is set to 200 min －１ The pressure (processing load) applied to the substrate may be 100 kPa or less, from the viewpoint of easily suppressing polishing scratches on the surface to be polished. During polishing, a polishing liquid may be continuously supplied to the polishing pad by a pump or the like. There is no limit to the amount of supply, but the surface of the polishing pad may be constantly covered with the polishing liquid. After polishing is completed, the substrate may be thoroughly washed in running water, and then water droplets adhering to the substrate may be removed using a spin dryer or the like, followed by drying.

[0088] By polishing in this manner, surface irregularities can be eliminated, and a smooth surface can be obtained over the entire surface of the substrate. Furthermore, by repeating the steps of forming a film and polishing this film a predetermined number of times, a structure having a desired number of layers can be manufactured.

[0089] The substrate (structure) thus obtained can be used as various electronic components. Specific examples of electronic components include semiconductor elements; optical glasses such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, and optical waveguides made of glass and crystalline materials; end faces of optical fibers; optical single crystals such as scintillators; solid-state laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for magnetic disks; and magnetic heads.

[0090] <Manufacturing Method, etc.> The component manufacturing method according to this embodiment includes a component fabrication step in which a component is obtained using a substrate (a member to be polished) polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the component manufacturing method according to this embodiment. The component according to this embodiment is not particularly limited, and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing method according to this embodiment, an electronic component is obtained using a substrate polished by the polishing method according to this embodiment. As one aspect of the component manufacturing method according to this embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a substrate polished by the polishing method according to this embodiment. The component manufacturing method according to this embodiment may include a polishing step in which a substrate is polished by the polishing method according to this embodiment before the component fabrication step.

[0091] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a substrate (a polished member) polished by the polishing method according to this embodiment. The singulation process may be, for example, a process for dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to this embodiment, the electronic component manufacturing method according to this embodiment may include a process for singulating a substrate polished by the polishing method according to this embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to this embodiment, the semiconductor component manufacturing method according to this embodiment may include a process for singulating a substrate polished by the polishing method according to this embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0092] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a connection process in which a substrate (a polished member) polished by the polishing method according to this embodiment is connected (e.g., electrically connected) to another connected object. The connected object to be connected to the substrate polished by the polishing method according to this embodiment is not particularly limited and may be the substrate polished by the polishing method according to this embodiment, or may be a connected object different from the substrate polished by the polishing method according to this embodiment. In the connection process, the substrate and the connected object may be directly connected (connected in a state where the substrate and the connected object are in contact with each other), or the substrate and the connected object may be connected via another member (such as a conductive member). The connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0093] The connecting step may be a step of connecting a polished surface of a base polished by the polishing method according to this embodiment to a connected body, or a step of connecting a connecting surface of a base polished by the polishing method according to this embodiment to a connecting surface of a connected body. The connecting surface of the base may be a polished surface polished by the polishing method according to this embodiment. A connecting body including a base and a connected body can be obtained by the connecting step. In the connecting step, if the connecting surface of the base has a metal portion, the connected body may be brought into contact with the metal portion. In the connecting step, if the connecting surface of the base has a metal portion and the connecting surface of the connected body has a metal portion, the metal portions may be brought into contact with each other. The metal portion may contain copper.

[0094] The device according to this embodiment (for example, an electronic device such as a semiconductor device) includes a substrate polished by the polishing method according to this embodiment and at least one selected from the group consisting of the part according to this embodiment.

[0095] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0096] <Preparation of Cerium Oxide Powder> 40 kg of cerium carbonate hydrate was divided and placed in 10 alumina containers, and each was calcined in air at 830°C for 2 hours to obtain a total of 20 kg of yellow-white powder. Phase identification of this powder was performed using X-ray diffraction, and it was confirmed that the powder contained polycrystalline cerium oxide. The particle size of the powder obtained by calcination was observed using an SEM and was found to be in the range of 20 to 100 μm. Next, 20 kg of the cerium oxide powder was dry-pulverized using a jet mill to obtain cerium oxide powder. The specific surface area of ​​the cerium oxide powder after pulverization was 9.4 m ２ The specific surface area was measured by the BET method.

[0097] <Slurry Preparation> 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, approximately 6 mass%) acetic acid was added, and the mixture was stirred for 10 minutes to obtain a cerium oxide mixed solution. This cerium oxide mixed solution was transferred to another container over 30 minutes. During this time, the cerium oxide mixed solution was irradiated with ultrasonic waves at an ultrasonic frequency of 400 kHz within the pipe through which the solution was transferred.

[0098] The cerium oxide mixture described above, which had been delivered after ultrasonic irradiation, was placed in four 500 mL polyethylene containers, each containing 500 g ± 5 g. The cerium oxide mixture in each container was centrifuged for 2 minutes at a centrifugal force of 500 G applied to the periphery. After centrifugation, the supernatant fractions were collected from the containers. The supernatant fractions collected from the four containers were mixed together to obtain a slurry. The slurry contained approximately 6.0 mass% of cerium oxide particles based on the total mass of the slurry.

[0099] The slurry was diluted with pure water to a total mass of 1.0% by mass of abrasive grains, and the average particle size of the abrasive grains in this sample was measured using a laser diffraction / scattering particle size analyzer (Microtrac MT3300EXII, manufactured by MicrotracBEL Corp.). The average particle size of the abrasive grains was found to be 140 nm.

[0100] <Preparation of Additives> The following additives were prepared as components of the polishing liquid: 1H-indole-3-carboxylic acid, 1H-indole-3-acetic acid, 1H-indole-3-propionic acid, 1H-indole-3-methyl acetate, 3-methoxymethylindole, N-acetyl-DL-tryptophan (also known as rac-(αR ＊)-α-(acetylamino)-1H-indole-3-propionic acid) 5-Hydroxy-L-tryptophan 5-Hydroxyindole-3-acetic acid 5-Methoxyindole-3-acetic acid 8-Hydroxyquinoline (alias: 8-quinolinol) 1H-Benzotriazole 4-Quinolinecarboxylic acid 2,6-Dihydroxyquinoline Phthalazine L-Proline Benzohydroxamic acid Salicylaldoxime 4-Hydroxybenzoic acid 1,3,5-Trihydroxybenzene dihydrate (alias: phloroglucinol dihydrate) 2-Aminobenzaldehyde L-Phenylalanine 3-Hydroxy-2-pyridinecarboxylic acid (alias: 3-hydroxypicolinic acid) 5-Hydroxy-2-pyridinecarboxylic acid (alias: 5-hydroxypicolinic acid) 5-Amino-2-pyridinecarboxylic acid (alias: 5-aminopicolinic acid) 3-Pyridinecarboxylic acid (alias: nicotinic acid) 6-Methyl-2-pyridinecarboxylic acid (also known as 6-methylpicolinic acid) 1H-pyrrole-3-carboxylic acid

[0101] <Preparation of CMP Polishing Slurry> Polishing slurries were prepared by mixing the above-described slurries, the additives listed in Tables 1 to 5, a nonionic polymer (polyglycerin, weight-average molecular weight: 750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., product name: PGL#750), an acyclic alcohol (3-methoxy-3-methyl-1-butanol), and deionized water. Based on the total mass of the polishing slurries, the abrasive content was 1.0 mass%, the additives listed in Tables 1 to 5 were 0.10 mass%, the nonionic polymer content was 0.20 mass%, and the acyclic alcohol content was 8.96 mass%. Each polishing slurries contained acetic acid, as the acetic acid mixed during the preparation of the above-described slurries, in an amount corresponding to the respective abrasive content. The average particle size of the abrasive particles in the polishing slurries of each Example was equivalent to the average particle size of the abrasive particles in the above-described slurries.

[0102] <Zeta Potential Measurement> An appropriate amount of polishing liquid was placed in a "Delsa Nano C" polishing container manufactured by Beckman Coulter, Inc., and measurements were performed twice at 25°C. The average value of the displayed zeta potentials was obtained as the zeta potential. In each of the Examples and Comparative Examples, the zeta potential of the abrasive grains was positive.

[0103] <pH Measurement> The pH of the polishing solution was measured under the following conditions. The results are shown in Tables 1 to 5. Measurement temperature: 25°C Measuring device: HORIBA, Ltd., product name: 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 pH meter electrode was immersed in the polishing solution, and the pH was measured using the measuring device after 2 minutes or more had passed and the pH had stabilized.

[0104] <Evaluation of Dispersion Stability of Abrasive Grains> The polishing solution described above immediately after preparation was allowed to stand for one week (168 hours), and the average particle diameter of the abrasive grains was measured three hours and one week after preparation using the same method as for the average particle diameter of the abrasive grains in the slurry described above. The rate of change in the average particle diameter of the abrasive grains after three hours or one week was calculated as "(average particle diameter in the polishing solution after three hours or one week - average particle diameter of the abrasive grains in the slurry described above) / average particle diameter of the abrasive grains in the slurry described above] x 100." A case in which the rate of change in the average particle diameter of the abrasive grains after one week (and the rate of change in the average particle diameter of the abrasive grains after three hours) was 4% or less was evaluated as "A." A case in which the rate of change in the average particle diameter of the abrasive grains after one week was more than 4% but the rate of change in the average particle diameter of the abrasive grains after three hours was 4% or less was evaluated as "B." A case in which the rate of change in the average particle diameter of the abrasive grains after three hours was more than 4% was evaluated as "C." The results are shown in Tables 1 to 5.

[0105] <Evaluation of Polishing Properties> The polishing properties of the above-described polishing liquids were evaluated as follows.

[0106] (Evaluation Wafer) As evaluation wafers, a 200 mm diameter unpatterned blanket wafer (BKW, purchased from Advantec Co., Ltd.) having a silicon oxide film on its surface and a test patterned wafer (PTW, manufactured by Hitachi, Ltd.) were prepared. The initial film thickness of the silicon oxide film on the unpatterned blanket wafer was 1000 nm. The test patterned wafer had a silicon oxide film with fine irregularities, with the convex portions (line portions) having an initial step height of about 5000 nm higher than the concave portions (space portions). The convex and concave portions were formed by etching the concave portions by about 5000 nm from a state in which the initial film thickness of the silicon oxide film was about 6000 nm. The wiring was a line pattern formed within a 12 mm x 12 mm die unit, having parallel convex portions (line portions) each 30 μm wide and concave portions (space portions) 570 μm wide (pitch: 600 μm wide, L / S=30 / 570 μm, ratio of the area of ​​the convex portions to the total area of ​​the concave portions and convex portions: 5%).

[0107] (Polishing of silicon oxide film) The above-mentioned evaluation wafer was polished using a polishing device (manufactured by Applied Materials, product name: Mirra 3400). The above-mentioned evaluation wafer was set on a holder having an adsorption pad for attaching a substrate. A polishing pad made of porous urethane resin (K-groove groove, manufactured by DuPont (Dow), model number: IC-1010) was attached to a polishing platen with a diameter of 500 mm.

[0108] The holder was placed on the polishing pad with the polished surface of the evaluation wafer facing downwards, and the inner tube pressure, retainer ring pressure, and membrane pressure were set to 14 kPa, 21 kPa, and 14 kPa, respectively.

[0109] Then, the polishing pad and the evaluation wafer were each polished for 93 minutes while the polishing liquid was dropped onto the polishing pad at a flow rate of 200 mL / min. －１ and 87 min －１The polished surface was polished by rotating the wafer at a speed of 1000 rpm. The blanket wafer was polished for 30 seconds. The patterned wafer was polished for 60 seconds. The polished evaluation wafer was then thoroughly washed with pure water using a PVA brush (polyvinyl alcohol brush) and then dried.

[0110] (Evaluation of Polishing Characteristics) The change in thickness of the silicon oxide film before and after polishing was measured using an optical interference film thickness measuring device (trade name: AFT-5100, manufactured by Nanometrics Japan Co., Ltd.) as described below, and the polishing rate was obtained. The results are shown in Tables 1 to 5.

[0111] For blanket wafers, the change in film thickness was measured at a total of 41 measurement points (20 points on both sides of the center point), including the center point and points spaced 5 mm apart in the diameter direction from the center point (the next measurement point after the measurement point 95 mm from the center was 97 mm from the center). The change in film thickness over a 30-second polishing time was measured at these 41 points, and the average value was taken as the polishing rate for the blanket wafer.

[0112] For the patterned wafer, the amount of change in film thickness at the convex portion in the region of L / S = 30 μm / 570 μm was measured to obtain the polishing rate of the patterned wafer. The amount of change in film thickness at one central location of the convex portion (line pattern) formed within the central die unit (12 mm × 12 mm) of the patterned wafer was measured.

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] 10 ILD film, 20 wiring, 30 silicon oxide film, 40 contact plug, 100, 100a substrate, D step.

Claims

1. A polishing liquid for CMP comprising an abrasive grain, a nitrogen-containing compound, and water, wherein the abrasive grain contains cerium-based particles, the nitrogen-containing compound contains a compound A1 having a condensed ring, and the condensed ring has an aromatic five-membered ring containing one nitrogen atom.

2. The CMP polishing liquid according to claim 1, wherein the compound A1 has an indole ring.

3. The polishing liquid for CMP according to claim 1, wherein an alkyl group substituted with at least one group selected from the group consisting of a carboxy group and a carboxylate group is bonded to the aromatic five-membered ring.

4. The CMP polishing liquid according to claim 1, wherein the nitrogen-containing compound comprises 1H-indole-3-acetic acid.

5. The CMP polishing liquid according to claim 1, wherein the nitrogen-containing compound comprises N-acetyl-DL-tryptophan.

6. A polishing liquid for CMP comprising an abrasive, a nitrogen-containing compound, and water, wherein the abrasive comprises cerium-based particles, and the nitrogen-containing compound comprises a compound A2 having a quinoline ring and one hydroxyl group bonded to the quinoline ring.

7. A polishing liquid for CMP comprising an abrasive grain, a nitrogen-containing compound, and water, wherein the abrasive grain contains cerium-based particles, and the nitrogen-containing compound contains a compound A3 having an aromatic ring and a hydroxyl group bonded to a nitrogen atom.

8. The CMP polishing liquid according to claim 7, wherein the compound A3 has a benzene ring.

9. The CMP polishing liquid according to claim 7, wherein a hydroxyamide group is bonded to the aromatic ring.

10. A polishing liquid for CMP comprising an abrasive grain, a nitrogen-containing compound, and water, wherein the abrasive grain comprises cerium-based particles, and the nitrogen-containing compound comprises a compound A4 having a nitrogen-containing aromatic ring to which at least one group selected from the group consisting of a hydroxyl group and an amino group is bonded.

11. The CMP polishing liquid according to claim 10, wherein the compound A4 has a pyridine ring.

12. The polishing liquid for CMP according to claim 10, wherein at least one group selected from the group consisting of a carboxy group and a carboxylate group is further bonded to said nitrogen-containing aromatic ring.

13. The polishing liquid for CMP according to any one of claims 1 to 12, wherein the cerium-based particles contain cerium oxide.

14. The polishing liquid for CMP according to any one of claims 1 to 12, having a pH of 3.00 to 7.

00.

15. A polishing liquid set for CMP, in which the components of the polishing liquid for CMP according to any one of claims 1 to 12 are stored separately as a first liquid and a second liquid, the first liquid containing the abrasive grains and water, and the second liquid containing the nitrogen-containing compound and water.

16. A polishing method comprising a step of polishing a surface to be polished with the polishing liquid for CMP according to any one of claims 1 to 12.

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

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