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

Abstract

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

Description

Technical Field

[0001] The present invention relates to a CMP (chemical mechanical polishing) polishing liquid, a CMP polishing liquid kit, a polishing method and the like. Background Art

[0002] In the field of semiconductor manufacturing, as the performance of Very Large Scale Integration (VLSI) devices increases, there are limitations in achieving both high integration and high speed through miniaturization technology, which is an extension of the previous technology. Therefore, a technology is being developed that promotes the miniaturization of semiconductor elements while also achieving high integration in the vertical direction (i.e., multilayer wiring technology).

[0003] In the process of manufacturing devices with multilayered wiring, CMP technology is one of the most important technologies. CMP technology is a technology for flattening the surface of a substrate obtained by forming a thin film on a substrate through chemical vapor deposition (CVD) or the like. For example, in order to ensure the focal depth of photolithography, flattening treatment based on CMP is indispensable. If there are unevenness on the surface of the substrate, it will cause inconveniences such as failure to focus during the exposure process and failure to fully form a fine wiring structure. In addition, CMP technology is also used in the process of forming element separation (inter-element separation. STI: shallow trench isolation)) areas by polishing plasma oxide films (BPSG, HDP-SiO2, p-TEOS, etc.) during the manufacturing process of the device; forming an ILD film (interlayer insulating film. An insulating film that electrically insulates metal parts (wiring, etc.) in the same layer from each other); and a process of flattening a plug (for example, an Al·Cu plug) after burying a film containing silicon oxide in a metal wiring.

[0004] CMP is usually performed using a device capable of supplying a polishing liquid to a polishing pad. Furthermore, the surface of the substrate is polished by supplying a polishing liquid between the surface of the substrate and the polishing pad while pressing the substrate to the polishing pad. Thus, in CMP technology, a polishing liquid is one of the essential technologies, and various polishing liquids have been developed so far in order to obtain a high-performance polishing liquid (for example, refer to the following patent document 1).

[0005] In the process of applying the CMP technology as described above, in particular, in the CMP process of the ILD film, it is necessary to grind silicon oxide at a high grinding speed. Therefore, in the CMP process of the ILD film, a silica-based polishing liquid (a polishing liquid using abrasive grains containing silica-based particles) with a high grinding speed is mainly used (for example, refer to the following patent document 2). However, in the silica-based polishing liquid, there is a tendency that it is difficult to control the grinding scratches that are the cause of defects. In addition, with the miniaturization of wiring in recent years, it is expected to reduce grinding scratches in the CMP process of the ILD film, but unlike the CMP process of the insulating film for the element isolation area, mirror polishing is generally not performed. Therefore, the use of a cerium-based polishing liquid (a polishing liquid using abrasive grains containing cerium-based particles) that has fewer grinding scratches than a silica-based polishing liquid is being studied (for example, refer to the following patent document 3).

[0006] Previous technical literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2008-288537

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 9-316431

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 10-102038 Summary of the invention

[0011] Technical issues to be solved by the invention

[0012] However, it is sometimes difficult to achieve a high polishing rate for silicon oxide in a cerium-based polishing liquid, especially in the polishing of a patterned wafer having a concave-convex pattern consisting of convex portions (such as line portions) and concave portions (such as space portions).

[0013] One aspect of the present invention is to provide a CMP polishing liquid that can achieve a high polishing rate of silicon oxide on a convex portion when polishing a pattern wafer having a concave-convex pattern. Another aspect of the present invention is to provide a CMP polishing liquid kit for obtaining the CMP polishing liquid. Another aspect of the present invention is to provide a polishing method using the CMP polishing liquid.

[0014] Means for solving technical problems

[0015] The present invention relates to the following [1] to

[17] in several aspects.

[0016] [1] A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes a compound A1 having a condensed ring having an aromatic five-membered ring containing one nitrogen atom.

[0017] [2] The CMP polishing liquid according to [1], wherein

[0018] The compound A1 has an indole ring.

[0019] [3] The CMP polishing liquid according to [1] or [2], wherein

[0020] An alkyl group substituted with at least one selected from the group consisting of a carboxyl group and a carboxylate group is bonded to the aromatic 5-membered ring.

[0021] [4] The CMP polishing liquid according to any one of [1] to [3], wherein

[0022] The nitrogen-containing compound comprises 1H-indole-3-acetic acid.

[0023] [5] The CMP polishing liquid according to any one of [1] to [4], wherein

[0024] The nitrogen-containing compound comprises N-acetyl-DL-tryptophan.

[0025] [6] A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes a compound A2 having a quinoline ring and one hydroxyl group bonded to the quinoline ring.

[0026] [7] A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound, and water, wherein the abrasive grains include cerium-based particles, and the nitrogen-containing compound includes a compound A3 having an aromatic ring and a hydroxyl group bonded to a nitrogen atom.

[0027] [8] The CMP polishing liquid according to [7], wherein

[0028] The compound A3 has a benzene ring.

[0029] [9] The CMP polishing liquid according to [7] or [8], wherein

[0030] The hydroxyamide group is bonded to the aromatic ring.

[0031]

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

[0032]

[11] The CMP polishing liquid according to

[10] , wherein

[0033] The compound A4 has a pyridine ring.

[0034]

[12] The CMP polishing liquid according to

[10] or

[11] , wherein

[0035] At least one selected from the group consisting of a carboxyl group and a carboxylate group is further bonded to the nitrogen-containing aromatic ring.

[0036]

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

[12] , wherein

[0037] The cerium-based particles include cerium oxide.

[0038]

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

[13] , wherein

[0039] The pH is 3.00~7.00.

[0040]

[15] A CMP polishing liquid kit, wherein:

[0041] The components contained in the CMP polishing liquid according to any one of [1] to

[14] are separated and stored into a first liquid and a second liquid, wherein the first liquid contains the abrasive grains and water, and the second liquid contains the nitrogen-containing compound and water.

[0042]

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

[14] .

[0043]

[17] The grinding method according to

[16] , wherein:

[0044] The polished surface includes silicon oxide.

[0045] Effects of the Invention

[0046] According to one aspect of the present invention, there is provided a CMP polishing liquid which can achieve a high polishing rate of silicon oxide on a convex portion when polishing a pattern wafer having a concave-convex pattern. According to another aspect of the present invention, there is provided a CMP polishing liquid kit for obtaining the CMP polishing liquid. According to another aspect of the present invention, there is provided a polishing method using the CMP polishing liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a schematic cross-sectional view showing a process of polishing the ILD film. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present invention will be described in detail.

[0049] In this specification, the numerical range represented by "~" means a range including the numerical values ​​recorded before and after "~" as the minimum and maximum values, respectively. "Above A" in the numerical range refers to A and the range exceeding A. "Below A" in the numerical range refers to A and the range less than A. In the numerical range recorded in stages in this specification, the upper limit or lower limit of the numerical range of a certain stage can be arbitrarily combined with the upper limit or lower limit of the numerical range of another stage. In the numerical range recorded in this specification, the upper limit or lower limit of its numerical range can be replaced by the value shown in the embodiment. "A or B" can include either A and B, or both. The materials exemplified in this specification can be used alone or in combination of two or more unless otherwise specified. When there are multiple substances belonging to each component in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. The term "layer" or "film" includes not only a structure formed on the entire surface when observed as a top view, but also a structure formed on a part of the shape. The term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process can be achieved. Hydroxyl groups do not include OH structures included in carboxyl groups.

[0050] <Polishing fluid for CMP>

[0051] The CMP polishing liquid involved in this embodiment (including the first to fourth embodiments. The same applies hereinafter) is a CMP polishing liquid (hereinafter, depending on the situation, simply referred to as "polishing liquid") containing abrasive grains, a nitrogen-containing compound and water. The abrasive grains include cerium-based particles (particles containing cerium-based compounds). The nitrogen-containing compound of the polishing liquid involved in the first embodiment includes a compound A1 having a condensed ring, and the condensed ring has an aromatic 5-membered ring containing one nitrogen atom. The nitrogen-containing compound of the polishing liquid involved in the second embodiment includes a compound A2 having a quinoline ring and a hydroxyl group bonded to the quinoline ring. The nitrogen-containing compound of the polishing liquid involved in the third embodiment includes a compound A3 having an aromatic ring and a hydroxyl group bonded to a nitrogen atom. The nitrogen-containing compound of the polishing liquid involved in the fourth embodiment includes a compound A4 having a nitrogen-containing aromatic ring bonded to at least one selected from the group consisting of a hydroxyl group and an amino group.

[0052] According to the polishing liquid involved in the present embodiment, a high polishing rate of silicon oxide on the convex part can be achieved in the polishing of a pattern wafer having a concave-convex pattern composed of convex parts (e.g., Line parts) and concave parts (e.g., Space parts). For example, a high polishing rate of silicon oxide on the convex part can be achieved in the polishing of an area where Line / Space (L / S)=30μm / 570μm in the pattern wafer. According to the polishing liquid involved in the present embodiment, in the evaluation method described in the examples described later, the polishing rate of silicon oxide on the convex part in the area where L / S=30μm / 570μm can be, for example, 300nm / min or more (preferably 400nm / min or more, 500nm / min or more, 1000nm / min or more, 1500nm / min or more, 2000nm / min or more, etc.).

[0053] The main reason why a high polishing rate of silicon oxide in the convex portion can be achieved in polishing of a pattern wafer is not clear, but is presumed as follows. However, the main reason is not limited to the following.

[0054] That is, even if high-speed polishing of silicon oxide in a blanket wafer without a concave-convex pattern is possible by using a polishing liquid containing abrasive grains including cerium-based particles, a high polishing rate for silicon oxide in the convex portions of the patterned wafer cannot sometimes be achieved. In particular, in the polishing of low-density pattern areas such as L / S=30μm / 570μm where high polishing pressure can be easily and effectively applied, a peculiar phenomenon occurs in which a high polishing rate for silicon oxide in the convex portions cannot sometimes be achieved.

[0055] On the other hand, according to the polishing liquid involved in this embodiment, by using at least one nitrogen-containing compound A selected from the group consisting of compound A1, compound A2, compound A3 and compound A4, the interaction between the polishing liquid and the silicon oxide on the convex portion caused by the ring structure, functional groups, etc. of the nitrogen-containing compound A is enhanced (for example, the chemical reaction between the cerium-based particles in the polishing liquid and the silicon oxide on the convex portion (reaction caused by the bonding of Si-O-Ce) is promoted), thereby obtaining a high polishing speed for the silicon oxide on the convex portion, thereby achieving a high polishing speed for the silicon oxide on the convex portion in the polishing of the area of ​​L / S=30μm / 570μm in the pattern wafer.

[0056] The polishing liquid can be used to flatten the polished surface by polishing a pattern wafer having a concave-convex pattern to remove the convex portion. In this case, from the viewpoint of obtaining high flatness or shortening the polishing time required for flattening, it is sometimes required to achieve a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer having a concave-convex pattern relative to silicon oxide in a blanket wafer without a concave-convex pattern.

[0057] According to one mode of the polishing liquid involved in the present embodiment, a high polishing rate ratio of silicon oxide at the convex portion of a pattern wafer having a concave-convex pattern to silicon oxide in a blanket wafer without a concave-convex pattern can be achieved, for example, a high polishing rate ratio of silicon oxide at the convex portion in the area of ​​Line / Space (L / S) = 30μm / 570μm of the pattern wafer to silicon oxide in a blanket wafer without a concave-convex pattern can be achieved. According to one mode of the polishing liquid involved in the present embodiment, in the evaluation method described in the examples described later, the polishing rate ratio of silicon oxide at the convex portion in the area of ​​L / S = 30μm / 570μm of the pattern wafer to silicon oxide in 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.). By obtaining a high polishing rate ratio of silicon oxide at the convex portion of a pattern wafer having a concave-convex pattern to silicon oxide in a blanket wafer without a concave-convex pattern, high flatness can be achieved as a characteristic that can selectively polish the convex portion.

[0058] According to one mode of the polishing liquid involved in the present embodiment, high-speed polishing of silicon oxide in a blanket wafer without a concave-convex pattern can be achieved, and a high polishing speed of silicon oxide in a convex portion can be achieved in the polishing of a patterned wafer. According to one mode of the polishing liquid involved in the present embodiment, in the evaluation method described in the examples described later, as the polishing speed of silicon oxide in a blanket wafer, 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.) can be obtained.

[0059] In the process of forming the element separation region, it is sometimes required to suppress the polishing speed of the silicon nitride film used as a barrier layer as the base of the silicon oxide film, and sometimes it is required to have a high polishing selectivity of silicon oxide relative to silicon nitride (polishing speed of silicon oxide / polishing speed of silicon nitride). According to one form of the polishing liquid involved in the present embodiment, a sufficiently small polishing speed of silicon nitride can be obtained, and a high polishing selectivity of silicon oxide relative to silicon nitride can be obtained. In this case, it is suitable for polishing when forming the element separation region. According to one form of the polishing liquid involved in the present embodiment, in the evaluation method described in the examples described later, as the polishing speed of silicon nitride in the blanket wafer, for example, 150nm / min or less (preferably 100nm / min or less, 50nm / min or less, 10nm / min or less, 5nm / min or less, etc.) can be obtained.

[0060] The polishing liquid involved in this embodiment can be used for CMP of semiconductor wafer materials, for example, can be used for polishing a silicon oxide film provided on the surface of a semiconductor wafer. The polishing liquid involved in this embodiment can be used in the CMP process of an ILD film. According to one mode of the polishing liquid involved in this embodiment, a high polishing speed can be obtained, and the aggregation of abrasive grains and the generation of polishing scratches can be suppressed, and high flatness can be obtained.

[0061] (Abrasive particles)

[0062] In the polishing liquid according to the present embodiment, the abrasive grains include cerium-based particles (particles containing a cerium-based compound). By using cerium-based particles as abrasive grains, polishing scratches generated on the polished surface can be easily reduced, and a high polishing rate of silicon oxide at the convex portion of the pattern wafer can be obtained.

[0063] Cerium compounds as 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, cerium carbonate, etc. From the perspective of easily obtaining a high polishing rate of silicon oxide in the convex portion of the pattern wafer (the convex portion of the L / S=30μm / 570μm region, etc.: the same below) or from the perspective of easily obtaining a polished surface with few polishing scratches and excellent flatness, the cerium-based particles may include cerium oxide. Cerium oxide may be CeO2 (cerium (IV) oxide, cerium dioxide) or Ce2O3 (cerium (III) oxide).

[0064] The cerium oxide particles (particles containing cerium oxide) may contain polycrystalline cerium oxide having grain boundaries. Particles containing polycrystalline cerium oxide have the property of becoming finer during polishing while the active surface is gradually revealed, and can maintain a high polishing rate of silicon oxide at the convex portion of the pattern wafer.

[0065] As a method for producing cerium oxide particles, a calcination method, an oxidation method based on hydrogen peroxide, etc., etc. can be cited. During calcination, the temperature during calcination can be 350 to 900° C. When the cerium oxide particles are agglomerated, the particles can be mechanically crushed. As a crushing method, for example, dry crushing based on a jet mill or wet crushing based on a planetary bead mill can be used. The jet mill can use, for example, the jet mill described in "Collection of Chemical Industry Papers", Vol. 6, No. 5, (1980), pp. 527 to 532.

[0066] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the Zeta potential (surface potential) of the abrasive grains in the polishing liquid can be positive (the Zeta potential can exceed 0 mV). 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., trade name: DelsaNano C). The Zeta potential of the abrasive grains can be adjusted using additives. For example, by contacting the abrasive grains with an acid component (e.g., acetic acid), abrasive grains having a positive Zeta potential can be obtained.

[0067] From the viewpoint of easily obtaining a high polishing speed of silicon oxide at the convex portion of the pattern wafer, 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 suppressing the generation of polishing scratches, 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 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.

[0068] The "average particle size of the abrasive grains" refers to the central value of the volume distribution obtained by measuring a sample of abrasive grain dispersion using a particle size distribution measuring device (e.g., a laser diffraction / scattering particle size distribution measuring device), and can be measured using a product name: Microtrac MT3300EXII manufactured by MicrotracBEL Corp. For example, the abrasive grains are dispersed in water, and the sample is prepared by adjusting the content of the abrasive grains to have a scattering intensity suitable for the measurement range, and the sample is placed in a measuring device to measure the average particle size. When measuring the particle size of the abrasive grains in the polishing liquid, the content of the abrasive grains in the polishing liquid can be adjusted to obtain the content of the abrasive grains having a scattering intensity suitable for the measurement range to prepare a sample, and the sample is measured using the same method. 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 effectively obtained.

[0069] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the content of the abrasive grains can be within the following ranges based on the total mass of the polishing liquid. The content of the abrasive grains can be 0.01 mass %, 0.05 mass %, 0.10 mass %, 0.20 mass %, 0.30 mass %, 0.40 mass %, 0.50 mass %, 0.60 mass %, 0.70 mass %, 0.80 mass %, 0.90 mass %, or 1.0 mass %. From the viewpoint of easily achieving excellent dispersion stability of the abrasive grains, the content of the abrasive grains can be 20 mass %, 15 mass %, 12 mass %, 10 mass %, 8.0 mass %, 6.0 mass %, 5.0 mass %, 4.0 mass %, 3.0 mass %, 2.0 mass %, 1.5 mass %, or 1.0 mass %. 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 %.

[0070] (Nitrogen-containing compounds)

[0071] The nitrogen-containing compound of 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 of the polishing liquid according to this embodiment may include nitrogen-containing compound A and nitrogen-containing compounds other than nitrogen-containing compound A.

[0072] The nitrogen-containing compound of the polishing liquid involved in the first embodiment includes a compound A1 having a condensed ring C1, and the condensed ring C1 has an aromatic 5-membered ring containing one nitrogen atom (hereinafter referred to as "5-membered ring C11"). In the 5-membered ring C11, the number of nitrogen atoms (nitrogen atoms constituting the 5-membered ring C11) is one. As the 5-membered ring C11, a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, etc. can be cited. Regarding the condensed ring C1, from the viewpoint of easily obtaining a high polishing speed of silicon oxide at the convex portion of the pattern wafer, as the 5-membered ring C11, a pyrrole ring can be included.

[0073] The condensed ring C1 has a 5-membered ring C11 and other rings C12. Ring C12 can be an aromatic ring, a non-aromatic ring (alicyclic ring, etc.), a heterocyclic ring, or a non-heterocyclic ring. From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, compound A1 can have a condensed ring having a 5-membered ring C11 and an aromatic ring, a condensed ring having a 5-membered ring C11 and a non-heterocyclic ring, or a condensed ring having a 5-membered ring C11 and a benzene ring. From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the condensed ring C1 can be a condensed ring formed by a 5-membered ring C11 and other rings C12.

[0074] Compound A1 may have an indole ring as condensed ring C1 from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer. Compound A1 may have a ring other than condensed ring C1, but may not have a ring other than condensed ring C1 from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer.

[0075] Compound A1 may have a nitrogen atom not constituting a 5-membered ring C11 or a nitrogen atom not constituting a ring in addition to the nitrogen atom of the 5-membered ring C11. The number of nitrogen atoms in Compound A1 may be 1 or 2 from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer.

[0076] The substituent may be bonded to the condensed ring C1. The substituent may be bonded to the 5-membered ring C11 or to the ring C12. As a substituent, substituted or unsubstituted alkyl, hydroxyl, carboxyl, carboxylate, aldehyde, alkoxy, ester, substituted or unsubstituted amino, amide (except hydroxyamide), hydroxyamide, nitro, cyano, mercapto, halo (fluoro, chloro, bromo, iodo, etc.) and the like may be cited. With regard to the number of carbon atoms of the alkyl group (excluding the number of carbon atoms of the substituent), from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to silicon oxide in the blanket wafer, or from the viewpoint of easily obtaining a high polishing selectivity of silicon oxide relative to silicon nitride, it may be 1, 2 or 3, and from the viewpoint of easily achieving excellent dispersion stability of abrasive particles, it may be 1 or 2.

[0077] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of a pattern wafer, from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of a pattern wafer to silicon oxide in a blanket wafer, or from the viewpoint of easily obtaining a high polishing selectivity of silicon oxide relative to silicon nitride, at least one selected from the group consisting of substituted or unsubstituted alkyl groups, hydroxyl groups, carboxyl groups, carboxylate groups and alkoxy groups can be bonded to the condensed ring C1, and an alkyl group substituted by at least one selected from the group consisting of carboxyl groups, carboxylate groups, alkoxy groups, ester groups and amino groups (unsubstituted amino groups, acetylamino groups, etc.) can be bonded to the condensed ring C1.

[0078] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in the blanket wafer, or from the viewpoint of easily obtaining a high polishing selectivity of silicon oxide relative to silicon nitride, at least one selected from the group consisting of substituted or unsubstituted alkyl groups, carboxyl groups, and carboxylate groups may be bonded to the 5-membered ring C11, at least one substituted alkyl selected from the group consisting of carboxyl groups, carboxylate groups, alkoxy groups, ester groups, and amino groups (unsubstituted amino groups, acetylamino groups, etc.) may be bonded to the 5-membered ring C11, and at least one substituted alkyl selected from the group consisting of carboxyl groups and carboxylate groups may be bonded to the 5-membered ring C11. From the viewpoint of easily achieving excellent dispersion stability of abrasive particles, at least one substituted alkyl selected from the group consisting of carboxyl groups, carboxylate groups, ester groups, and amino groups (unsubstituted amino groups, acetylamino groups, etc.) may be bonded to the 5-membered ring C11.

[0079] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the substituent bonded to the 5-membered ring C11 may be bonded to the third atom (e.g., carbon atom) relative to the nitrogen atom in the 5-membered ring C11 (e.g., pyrrole ring). From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, at least one selected from the group consisting of a hydroxyl group and an alkoxy group may be bonded to the ring C12. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the ring C12 may be unsubstituted.

[0080] Regarding the nitrogen-containing compound of the polishing liquid involved in the first embodiment, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, as compound A1, it can include at least one selected from the group consisting of 1H-indole-3-carboxylic acid, 1H-indole-3-acetic acid, 1H-indole-3-propionic acid, 1H-indole-3-acetic acid methyl ester, 3-methoxymethylindole, N-acetyl-DL-tryptophan, 5-hydroxy-L-tryptophan, 5-hydroxyindole-3-acetic acid and 5-methoxyindole-3-acetic acid, and can also include 1H-indole-3-acetic acid and can also include N-acetyl-DL-tryptophan.

[0081] The nitrogen-containing compound of the polishing liquid involved in the second embodiment includes a compound A2 having a quinoline ring and a hydroxyl group bonded to the quinoline ring. Compound A2 has a hydroxyl group directly bonded to the quinoline ring. In compound A2, the number of hydroxyl groups bonded to the quinoline ring is one. Compound A2 may have a hydroxyl group not bonded to the quinoline ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may not have a hydroxyl group not bonded to the quinoline ring.

[0082] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the hydroxyl 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.

[0083] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern 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 polishing rate for silicon oxide at the convex portion of the pattern wafer, it may not have nitrogen atoms other than the nitrogen atoms constituting the quinoline ring.

[0084] Substituents other than hydroxyl groups may be bonded to the quinoline ring. As substituents, substituted or unsubstituted alkyl groups, carboxyl groups, carboxylate groups, aldehyde groups, alkoxy groups, ester groups, substituted or unsubstituted amino groups, amide groups (except hydroxyamide groups), hydroxyamide groups, nitro groups, cyano groups, mercapto groups, halogenated groups (fluoro groups, chloro groups, bromo groups, iodo groups, etc.) and the like may be cited. From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, substituents other than hydroxyl groups may not be bonded to the quinoline ring.

[0085] The nitrogen-containing compound in the polishing liquid according to the second embodiment may contain 8-hydroxyquinoline as the compound A2 from the viewpoint of easily obtaining a high polishing rate for silicon oxide on the convex portions of the pattern wafer.

[0086] The nitrogen-containing compound of the polishing liquid according to the third embodiment includes a compound A3 having an aromatic ring and a hydroxyl group bonded to a nitrogen atom. The compound A3 has a hydroxyl group directly bonded to a nitrogen atom.

[0087] The nitrogen atom bonded to the hydroxyl group may be directly bonded to the aromatic ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may not be directly bonded to the aromatic ring. The nitrogen atom bonded to the hydroxyl group may be a nitrogen atom constituting a ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may be a nitrogen atom not constituting a ring.

[0088] Compound A3 may have an aromatic ring constituting a condensed ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may have a monocyclic aromatic ring (an aromatic ring that does not constitute a condensed ring). Regarding compound A3, as an aromatic ring, it may have a heterocyclic ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may have a non-heterocyclic ring or a benzene ring.

[0089] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of aromatic rings or the number of benzene rings in compound A3 may be 1. For example, when compound A3 has a condensed ring consisting of two aromatic rings, the number of aromatic rings is 2 (the number of benzene rings is also the same). From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of nitrogen atoms in compound A3 may be 1.

[0090] The number of hydroxyl groups in compound A3 may be 1 or 2 from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, 1 from the viewpoint of easily obtaining a higher polishing rate of silicon oxide at the convex portion of the pattern wafer, and 2 from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in a blanket wafer or easily obtaining a high polishing selectivity of silicon oxide to silicon nitride. In compound A3, the number of hydroxyl groups bonded to nitrogen atoms may be 1 from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer. From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, compound A3 may not have a hydroxyl group not bonded to a nitrogen atom. From the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in a blanket wafer or easily obtaining a high polishing selectivity of silicon oxide to silicon nitride, compound A3 may have a hydroxyl group not bonded to a nitrogen atom (for example, a hydroxyl group bonded to an aromatic ring) in addition to the hydroxyl group bonded to the nitrogen atom.

[0091] Substituents can be bonded to aromatic rings. As substituents, substituted or unsubstituted alkyl, hydroxyl, carboxyl, carboxylate, aldehyde, alkoxy, ester, substituted or unsubstituted amino, amide (except hydroxyamide), hydroxyamide, nitro, cyano, mercapto, halo (fluoro, chloro, bromo, iodo, etc.) etc. can be cited. From the viewpoint of high polishing rate of silicon oxide at the convex part of pattern wafer, hydroxyamide can be bonded to aromatic rings. From the viewpoint of high polishing rate ratio of silicon oxide at the convex part of pattern wafer relative to silicon oxide in blanket wafer or high polishing selectivity of silicon oxide relative to silicon nitride, hydroxyl can be bonded to aromatic rings.

[0092] Regarding the nitrogen-containing compound of the polishing liquid involved in the third embodiment, as compound A3, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, it can include at least one selected from the group consisting of benzohydroxamic acid and salicylaldehyde oxime; from the viewpoint of easily obtaining a higher polishing rate for silicon oxide at the convex portion of the pattern wafer, it can include benzohydroxamic acid; from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in a blanket wafer or from the viewpoint of easily obtaining a high polishing selectivity of silicon oxide to silicon nitride, it can include salicylaldehyde oxime.

[0093] The nitrogen-containing compound of the polishing liquid involved in the fourth embodiment includes a compound A4 having a nitrogen-containing aromatic ring C4 bonded to at least one selected from the group consisting of a hydroxyl group and an amino group. Regarding compound A4, as a substituent directly bonded to the nitrogen-containing aromatic ring C4, at least one selected from the group consisting of a hydroxyl group and an amino group is included. In a compound having a condensed ring consisting of a nitrogen-containing aromatic ring X1 and a ring X2 that does not belong to the nitrogen-containing aromatic ring, when the hydroxyl group and the amino group are not bonded to the nitrogen-containing aromatic ring X1, and at least one selected from the group consisting of a hydroxyl group and an amino group is bonded to the ring X2, such a compound does not belong to compound A4.

[0094] Regarding at least one selected from the group consisting of hydroxyl groups and amino groups, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the at least one selected from the group consisting of the third atom (e.g., a carbon atom) and the fifth atom (e.g., a carbon atom) relative to the nitrogen atom in the nitrogen-containing aromatic ring C4 can be bonded; from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in the blanket wafer, the at least one selected from the group consisting of hydroxyl groups and amino groups can be bonded to the third atom (e.g., a carbon atom) relative to the nitrogen atom in the nitrogen-containing aromatic ring C4; from the viewpoint of easily obtaining a higher polishing rate for silicon oxide at the convex portion of the pattern wafer or easily obtaining a high polishing selectivity of silicon oxide relative to silicon nitride, the at least one selected from the group consisting of hydroxyl groups and amino groups can be bonded to the fifth atom (e.g., a carbon atom) relative to the nitrogen atom in the nitrogen-containing aromatic ring C4.

[0095] As the nitrogen-containing aromatic ring C4, there can be mentioned: 6-membered rings such as pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring; 5-membered rings such as pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, etc. With regard to compound A4, from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, as the nitrogen-containing aromatic ring C4, it can have a 6-membered ring or a pyridine ring. With regard to compound A4, as the nitrogen-containing aromatic ring C4, it can have a nitrogen-containing aromatic ring constituting a condensed ring, but from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it can also have a monocyclic nitrogen-containing aromatic ring (a nitrogen-containing aromatic ring that does not constitute a condensed ring). From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the number of nitrogen-containing aromatic rings C4 in compound A4 can be 1.

[0096] Compound A4 may have a hydroxyl group not bonded to the nitrogen-containing aromatic ring, or may have an amino group not bonded to the nitrogen-containing aromatic ring. However, from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, it may not have a hydroxyl group not bonded to the nitrogen-containing aromatic ring, may not have an amino group not bonded to the nitrogen-containing aromatic ring, and may not have both a hydroxyl group and an amino group not bonded to the nitrogen-containing aromatic ring.

[0097] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of hydroxyl groups in compound A4 (the total of hydroxyl groups bonded to the nitrogen-containing aromatic ring and hydroxyl groups not bonded to the nitrogen-containing aromatic ring) may be 1. In compound A4, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of hydroxyl groups bonded to the nitrogen-containing aromatic ring may be 1.

[0098] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of amino groups in compound A4 (the total of the amino groups bonded to the nitrogen-containing aromatic ring and the amino groups not bonded to the nitrogen-containing aromatic ring) may be 1. In compound A4, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of amino groups bonded to the nitrogen-containing aromatic ring may be 1.

[0099] The number of nitrogen atoms in compound A4 may be 1 or 2 from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, 1 from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer to silicon oxide in the blanket wafer or easily obtaining a high polishing selectivity of silicon oxide to silicon nitride, and 2 from the viewpoint of easily obtaining a higher polishing rate for silicon oxide at the convex portion of the pattern wafer. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the number of nitrogen atoms (nitrogen atoms constituting the nitrogen-containing aromatic ring) in the nitrogen-containing aromatic ring C4 may be 1.

[0100] Substituents other than hydroxyl and amino groups may be bonded to the nitrogen-containing aromatic ring C4. As substituents, substituted or unsubstituted alkyl, carboxyl, carboxylate, aldehyde, alkoxy, ester, amide (except hydroxyamide), hydroxyamide, nitro, cyano, mercapto, halogen (fluoro, chloro, bromo, iodo, etc.) and the like may be cited. From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, at least one selected from the group consisting of carboxyl and carboxylate may be bonded to the nitrogen-containing aromatic ring C4, and at least one selected from the group consisting of carboxyl and carboxylate may be bonded to the second atom (e.g., carbon atom) relative to the nitrogen atom in the nitrogen-containing aromatic ring C4.

[0101] Regarding the nitrogen-containing compound of the polishing liquid involved in the fourth embodiment, from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, as compound A4, it can include 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 can also include 5-hydroxy-2-pyridinecarboxylic acid.

[0102] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern 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 can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 98% by mass or more or 99% by mass or more, based on the overall nitrogen-containing compound (the overall nitrogen-containing compound contained in the polishing liquid). The nitrogen-containing compound contained in the polishing liquid can be substantially composed of nitrogen-containing compound A, compound A1, compound A2, compound A3 or compound A4 (substantially, 100% by mass of the nitrogen-containing compound contained in the polishing liquid is nitrogen-containing compound A, compound A1, compound A2, compound A3 or compound A4).

[0103] As 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, from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, based on the total mass of the polishing liquid, the content A can be within the following range. The content A can 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 can 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%.

[0104] As the mass ratio of the content of the nitrogen-containing compound A to the content of the abrasive grains (nitrogen-containing compound A / abrasive grains), the mass ratio of the content of the compound A1 to the content of the abrasive grains (compound A1 / abrasive grains), the mass ratio of the content of the compound A2 to the content of the abrasive grains (compound A2 / abrasive grains), the mass ratio of the content of the compound A3 to the content of the abrasive grains (compound A3 / abrasive grains), or the mass ratio of the content of the compound A4 to the content of the abrasive grains (compound A4 / abrasive grains), from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the mass ratio B may be within the following range. The 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.

[0105] The polishing liquid involved in this embodiment may contain a nonionic polymer. Examples of the nonionic polymer include polyglycerol, polyglycerol fatty acid esters, polyglycerol derivatives, polyoxyethylene distyrenated phenyl ethers, polyoxyethylene sorbitan monolaurate, polyoxyethylene lauryl ether, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene ether derivatives, polyoxypropylene glycerol ether, polyethylene glycol, methoxypolyethylene glycol, ethylene oxide adducts of acetylene glycols, and other ether surfactants; sorbitan fatty acid esters, glycerol borate fatty acid esters, and other ester surfactants; amino ether surfactants such as polyoxyethylene alkylamines; ether ester surfactants such as polyoxyethylene glycerol borate fatty acid esters and polyoxyethylene alkyl esters; fatty acid alkanolamides, polyoxyethylene fatty acid alkanolamides, and other alkanolamide surfactants; polyvinyl pyrrolidone; nonionic polyacrylamide; nonionic polydimethylacrylamide, and the like. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer, the nonionic polymer may include at least one selected from the group consisting of ether-type surfactants, ester-type surfactants, aminoether-type surfactants, ether-ester-type surfactants, alkanolamide-type surfactants, polyvinylpyrrolidone, nonionic polyacrylamide and nonionic polydimethylacrylamide, and may also include polypropylene glycol.

[0106] From the viewpoint of high polishing speed of silicon oxide at the convex part of the pattern wafer, the content of the nonionic polymer can be in the following range based on the total mass of the polishing liquid. The content of the nonionic polymer can be 0.01 mass %, 0.03 mass %, 0.05 mass %, 0.08 mass %, 0.10 mass %, 0.15 mass % or more, or 0.20 mass %. The content of the nonionic polymer can be 5.00 mass %, 3.00 mass %, 1.00 mass %, 0.80 mass %, 0.50 mass %, 0.30 mass % or 0.20 mass %. 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%.

[0107] The polishing liquid involved in this embodiment may contain acyclic alcohol. Acyclic alcohol is an alcohol without a cyclic structure. By using acyclic alcohol, the dispersion stability of the abrasive particles in the polishing liquid can be easily improved.

[0108] Examples of the acyclic alcohol 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. From the perspective of easily obtaining a high polishing rate for silicon oxide at the convex portion of the pattern wafer or easily achieving excellent dispersion stability of abrasive grains, the acyclic alcohol may include 3-methoxy-3-methyl-1-butanol.

[0109] From the viewpoint of the high grinding speed of silicon oxide at the convex part of the pattern wafer that is easy to obtain or the viewpoint of the dispersion stability of excellent abrasive particles that is easy to realize, based on the total mass of the grinding liquid, the content of acyclic alcohol can be within the following range. The content of acyclic alcohol can be more than 0.01 mass %, more than 0.05 mass %, more than 0.10 mass %, more than 0.50 mass %, more than 1.0 mass %, more than 1.2 mass %, more than 1.4 mass %, more than 1.5 mass %, more than 2.0 mass %, more than 3.0 mass %, more than 5.0 mass % or more than 8.0 mass %. The content of acyclic alcohol can be less than 50 mass %, less than 30 mass %, less than 20 mass %, less than 10 mass %, less than 9.0 mass %, less than 8.0 mass %, less than 5.0 mass %, less than 3.0 mass %, less than 2.0 mass %, less than 1.5 mass % or less than 1.4 mass %. 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%.

[0110] (Other additives)

[0111] The polishing liquid according to the present embodiment may contain other components (components not belonging to the above-mentioned components) according to desired properties. Examples of such components include cationic compounds and pH adjusters described below.

[0112] The polishing liquid involved in the present embodiment may contain a compound a having a molecular weight of 100000 or less and having 4 or more hydroxyl groups, or may not contain compound a. The content of 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 involved in the present embodiment may contain a compound b having 4 or more amino groups, or may not contain compound b. The content of 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 compound a to the content of compound b (compound a / compound b) may be 0.10 or less or less than 0.10.

[0113] (water)

[0114] The water is not particularly limited, and may include at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0115] (pH)

[0116] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer or the viewpoint of easily achieving excellent dispersion stability of the abrasive grains, the pH of the polishing liquid involved in the present embodiment may be within the following range. The pH may be 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 may be measured by the method described in the Examples.

[0117] Since pH may vary depending on the type of compound used as an additive, a pH adjuster may be used to adjust pH within 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., aqueous ammonia), potassium hydroxide, and calcium hydroxide. The above-mentioned components such as nitrogen-containing compounds may be used for pH adjustment. From the viewpoint of improving productivity, the polishing liquid may be prepared without using a pH adjuster and the polishing liquid may be directly applied to CMP.

[0118] <Preparation and use of polishing liquid>

[0119] The polishing liquid involved in this embodiment can be classified into (a) ordinary type, (b) concentrated type and (c) multi-liquid type (for example, two-liquid type. Polishing liquid kit for CMP), and the preparation method and usage method are different according to the type. (a) Ordinary type is a polishing liquid that can be used directly without pretreatment such as dilution during polishing. (b) Concentrated type is a polishing liquid with concentrated ingredients compared to (a) ordinary type in consideration of the convenience of storage or transportation. (c) Multi-liquid type is a polishing liquid that is prepared in a state where the ingredients are divided into a plurality of liquids during storage or transportation (for example, divided into a first liquid containing a specified ingredient and a second liquid containing other ingredients), and these liquids are mixed for use when used.

[0120] (a) The ordinary type can be obtained by dissolving or dispersing abrasive grains and additives in water as the main dispersion medium. When preparing the polishing liquid, for example, a stirrer, a homogenizer, an ultrasonic disperser, a wet ball mill, etc. can be used. In the preparation process of the polishing liquid, the abrasive grains can be micronized so that the average particle size of the abrasive grains is within the desired range. The micronization of the abrasive grains can be implemented by a sedimentation classification method or a method using a high-pressure homogenizer. The sedimentation classification method is a method including a process of forcibly sedimenting a slurry containing abrasive grains with a centrifuge and a process of taking out only the supernatant. On the other hand, the method using a high-pressure homogenizer is a method of causing the abrasive grains in the dispersion medium to collide with each other under high pressure.

[0121] The (b) concentrated type is diluted with water immediately before use to obtain the desired content of the ingredients. After dilution, stirring can be performed for any period of time until the same liquid properties (pH, particle size of abrasive particles, etc.) and polishing properties (polishing speed of silicon oxide, polishing selectivity ratio of silicon oxide to silicon nitride, etc.) as those of the (a) ordinary type are obtained. In this (b) concentrated type, since the volume becomes smaller according to the degree of concentration, the cost required for storage and transportation can be reduced.

[0122] The concentration ratio may be 1.5 times or more, 2 times or more, 3 times or more, or 5 times or more. If the concentration ratio is 1.5 times or more, there is a tendency to easily obtain advantages related to storage and transportation compared with a case of less than 1.5 times. The concentration ratio may be 40 times or less, 20 times or less, or 15 times or less. If the concentration ratio is 40 times or less, there is a tendency to easily suppress the aggregation of the abrasive particles compared with a case of more than 40 times.

[0123] The (c) multi-liquid type has the advantage of being able to avoid agglomeration of abrasive grains by being appropriately divided into various liquids (first liquid, second liquid, etc.) compared to the (b) concentrated type. The components contained in each liquid can be arbitrary. The (c) multi-liquid type (polishing liquid set for CMP) is a polishing liquid set for mixing the first liquid (slurry) with the second liquid (additive liquid) to obtain a polishing liquid. For example, in the (c) multi-liquid type, the components contained in the polishing liquid for CMP are divided into the first liquid and the second liquid and stored, the first liquid contains abrasive grains and water, and the second liquid contains a nitrogen-containing compound (a nitrogen-containing compound containing nitrogen-containing compound A) and water. The first liquid and the second liquid may contain other components formulated as needed. In this case, in order to improve the dispersibility of the abrasive grains in the first liquid, any acid or base may be formulated into the first liquid to adjust the pH.

[0124] (c) Multi-liquid polishing liquid is useful when combining components that have a tendency to reduce polishing properties in a relatively short period of time due to agglomeration of abrasive particles when mixed. From the perspective of reducing the cost required for storage and transportation, at least one of the liquids (first liquid, second liquid, etc.) can be set to a concentrated type. In this case, when using the polishing liquid, it is sufficient to mix each liquid with water. The concentration ratio and pH of each liquid are arbitrary as long as the final mixture has the same degree of liquid properties and polishing properties as the ordinary type polishing liquid (a).

[0125] <Grinding method>

[0126] The polishing method according to the present embodiment includes a polishing step of polishing the polished surface using the polishing liquid according to the present 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. That is, the polishing method according to the present embodiment may include a polishing step of polishing the polished surface using the polishing liquid obtained by mixing the first liquid and the second liquid in the polishing liquid set. The polished surface may contain silicon oxide, silicon nitride, or silicon oxide and silicon nitride.

[0127] The grinding method involved in this embodiment can be as follows: the ground surface has a concave-convex pattern composed of convex parts (Line parts) and concave parts (Space parts), and the convex parts contain silicon oxide. The width of the convex parts in the concave-convex pattern can be less than 50μm, less than 40μm or less than 30μm. The width of the convex parts in the concave-convex pattern can be more than 10μm, more than 20μm or more than 30μm. The total of the width of the convex parts and the width of the concave parts in the concave-convex pattern can be less than 800μm, less than 700μm or less than 600μm. The total of the width of the convex parts and the width of the concave parts in the concave-convex pattern can be more than 400μm, more than 500μm or more than 600μm.

[0128] The polishing method involved in this embodiment is suitable for polishing a substrate having a silicon oxide film on the surface during the manufacturing process of the device. As devices, there can be cited: discrete semiconductors such as diodes, transistors, compound semiconductors, thermistors, varistors, thyristors, etc.; storage 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), flash memory, etc.; theoretical circuit elements such as microprocessors, DSPs, ASICs, etc.; integrated circuit elements such as compound semiconductors represented by MMIC (monolithic microwave integrated circuits); hybrid integrated circuits (hybrid ICs); light-emitting diodes; photoelectric conversion elements such as charge-coupled devices, etc.

[0129] The substrate is not limited to a substrate having only a silicon oxide film on the surface, and may be a substrate having a silicon nitride film, a polysilicon film, etc. on the surface in addition to the silicon oxide film. The substrate may be a substrate having the following films on a circuit board having specified wiring: an inorganic insulating film such as silicon oxide, glass, silicon nitride; a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc., etc.

[0130] Hereinafter, as an example of a process including the polishing method according to the present embodiment, a process of forming an ILD film (interlayer dielectric film) structure by CMP will be described. Figure 1 2 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. Figure 1 (a) is a schematic cross-sectional view showing a substrate before grinding. Figure 1 (b) is a schematic cross-sectional view showing the base body after grinding.

[0131] like Figure 1 As shown in (a), in a base body 100 before polishing, a 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 to cover the wiring 20. Since the silicon oxide film 30 is formed on the ILD film 10 on which the wiring 20 is formed, a portion on the wiring 20 becomes higher than other portions, thereby generating a step D on the surface of the silicon oxide film 30. The wiring 20 is connected to the lower wiring and the like through a contact plug 40 formed to penetrate the ILD film 10.

[0132] In the process of forming the ILD film structure, in order to eliminate the step difference D, the unnecessary parts protruding locally on the surface of the silicon oxide film 30 are preferentially removed by CMP. When grinding the silicon oxide film 30, the substrate 100 is arranged on the grinding component so that the surface of the silicon oxide film 30 abuts against the grinding component, and the surface of the silicon oxide film 30 is ground by the grinding component. More specifically, the grinding surface (surface) side of the silicon oxide film 30 is pressed against the grinding component of the grinding plate, and the grinding liquid is supplied between the grinding surface and the grinding component while the two are moved relative to each other to grind the silicon oxide film 30. As a result, the step difference D is eliminated, and finally, as shown in FIG. Figure 1 As shown in (b), the height of the wiring 20 portion on the surface of the silicon oxide film 30 is substantially the same as the height of other portions, and a substrate 100a including the silicon oxide film 30 (ILD film) having a flat surface can be obtained.

[0133] As a grinding device for grinding, for example, a device having a holder for holding a substrate, a grinding plate with a grinding pad attached thereto, and a mechanism for supplying a grinding liquid to the grinding pad can be used. As a grinding device, a grinding device manufactured by EBARA CORPORATION (model: EPO-111, EPO-222, F-REX200 and F-REX300), a grinding device manufactured by Applied Materials, Inc. (trade name: Mirra3400 and Reflexion), etc. can be cited. As the constituent material of the grinding pad, there is no particular restriction, for example, general non-woven fabrics, foamed polyurethane, porous fluororesin, etc. can be used. In addition, regarding the grinding pad, groove processing can be implemented to accumulate the grinding liquid.

[0134] There are no particular restrictions on the grinding conditions. From the perspective of preventing the substrate from flying out, the rotation speed of the grinding plate can be 200 min. -1 Below. From the viewpoint of easily suppressing the grinding scratches on the ground surface, the pressure (processing load) applied to the substrate can be below 100 kPa. During grinding, the grinding liquid can be continuously supplied to the grinding pad by a pump or the like. The supply amount is not limited, and the surface of the grinding pad can always be covered with the grinding liquid. After finishing the grinding, the substrate can be fully cleaned in running water, and then dried after removing the water droplets attached to the substrate using a rotary dryer or the like.

[0135] By polishing the surface to eliminate the unevenness in the above manner, a smooth surface can be obtained over the entire surface of the substrate. In addition, a structure having a desired number of layers can be manufactured by repeating the steps of forming a film and polishing the film a predetermined number of times.

[0136] The substrate (structure) obtained in this way can be used as various electronic parts. Specific examples of electronic parts include: semiconductor elements; optical glasses such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switch elements, and optical waveguides made of glass and crystalline materials; end faces of optical fibers; optical single crystals such as scintillators; solid laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for magnetic disks; magnetic heads, etc.

[0137] <Manufacturing method, etc.>

[0138] The manufacturing method of the part involved in the present embodiment includes a part manufacturing process of obtaining the part using a substrate (grinded part) ground by the grinding method involved in the present embodiment. The part involved in the present embodiment is a part obtained by the manufacturing method of the part involved in the present embodiment. The part involved in the present embodiment is not particularly limited, and can be an electronic part (for example, a semiconductor part such as a semiconductor package), a wafer (for example, a semiconductor wafer), or a chip (for example, a semiconductor chip). As one mode of the manufacturing method of the part involved in the present embodiment, in the manufacturing method of the electronic part involved in the present embodiment, an electronic part is obtained by using a substrate ground by the grinding method involved in the present embodiment. As one mode of the manufacturing method of the part involved in the present embodiment, in the manufacturing method of the semiconductor part involved in the present embodiment, a semiconductor part (for example, a semiconductor package) is obtained by using a substrate ground by the grinding method involved in the present embodiment. The manufacturing method of the part involved in the present embodiment may include a grinding process of grinding the substrate by the grinding method involved in the present embodiment before the part manufacturing process.

[0139] As one mode of the part manufacturing process, the manufacturing method of the part involved in the present embodiment may include a singulation process of singulating the substrate (the polished part) polished by the polishing method involved in the present embodiment. The singulation process may be, for example, a process of cutting a wafer (for example, a semiconductor wafer) polished by the polishing method involved in the present embodiment to obtain a chip (for example, a semiconductor chip). As one mode of the manufacturing method of the part involved in the present embodiment, the manufacturing method of the electronic part involved in the present embodiment may include a process of obtaining an electronic part (for example, a semiconductor part) by singulating the substrate polished by the polishing method involved in the present embodiment. As one mode of the manufacturing method of the part involved in the present embodiment, the manufacturing method of the semiconductor part involved in the present embodiment may include a process of obtaining a semiconductor part (for example, a semiconductor package) by singulating the substrate polished by the polishing method involved in the present embodiment.

[0140] As one mode of the part manufacturing process, the part manufacturing method involved in the present embodiment may include a connection process of connecting the substrate (grinded part) ground by the grinding method involved in the present embodiment and other connected bodies (for example, electrically connected). The connected body connected to the substrate ground by the grinding method involved in the present embodiment is not particularly limited, and may be the substrate ground by the grinding method involved in the present embodiment, or may be a connected body different from the substrate ground by the grinding method involved in the present 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 other components (conductive components, etc.). The connection process can be performed before the singulation process, after the singulation process, or before and after the singulation process.

[0141] The connection process may be a process of connecting the polished surface of the substrate polished by the polishing method involved in the present embodiment and the connected body, or may be a process of connecting the connecting surface of the substrate polished by the polishing method involved in the present embodiment and the connecting surface of the connected body. The connecting surface of the substrate may be the polished surface polished by the polishing method involved in the present embodiment. A connected body having a substrate and a connected body can be obtained by the connection process. In the connection process, when the connecting surface of the substrate has a metal part, the metal part can be brought into contact with the connected body. In the connection process, when the connecting surface of the substrate has a metal part and the connecting surface of the connected body has a metal part, the metal parts can be brought into contact with each other. The metal part may contain copper.

[0142] The device according to the present embodiment (for example, an electronic device such as a semiconductor device) includes at least one selected from the group consisting of a base body polished by the polishing method according to the present embodiment and the component according to the present embodiment.

[0143] Example

[0144] Hereinafter, the present invention will be described in further detail based on examples, but the present invention is not limited to these examples.

[0145] <Production of cerium oxide powder>

[0146] 40 kg of cerium carbonate hydrate was divided into 10 aluminum containers and sintered at 830°C in air for 2 hours to obtain a total of 20 kg of yellow-white powder. Phase identification of the powder was performed by X-ray diffraction, confirming that the powder contained polycrystalline cerium oxide. The particle size of the powder obtained by sintering was observed by SEM, and the result was in the range of 20 to 100 μm. Next, cerium oxide powder was obtained by dry-crushing 20 kg of cerium oxide powder using a jet mill. The specific surface area of ​​the cerium oxide powder after crushing is 9.4 m 2 / g. The specific surface area was measured by the BET method.

[0147] <Preparation of slurry>

[0148] 15.0 kg of the cerium oxide powder obtained in the above and 84.5 kg of deionized water were placed in a container and mixed. Then, 0.5 kg of 1M (mol / L, about 6 mass%) acetic acid was added and stirred for 10 minutes to obtain a cerium oxide mixed solution. The cerium oxide mixed solution was delivered to another container over 30 minutes. During this period, the cerium oxide mixed solution was irradiated with ultrasound at an ultrasonic frequency of 400 kHz in the delivery pipe.

[0149] 500 g ± 5 g of the cerium oxide mixed solution sent by ultrasonic irradiation were placed in four 500 mL polyethylene containers. The cerium oxide mixed solution in each container was centrifuged for 2 minutes under the condition that the centrifugal force applied to the periphery was 500 G. After centrifugation, the supernatant portion of the container was collected. The slurry was obtained by mixing the supernatant portions collected from the four containers. The slurry contained about 6.0 mass % of cerium oxide particles based on the total mass of the slurry.

[0150] The slurry was diluted with pure water so that the abrasive content was 1.0% by mass based on the total mass, thereby obtaining a sample for particle size measurement. The average particle size of the abrasive was measured for this sample using a laser diffraction / scattering particle size distribution analyzer (manufactured by Microtrac BEL Corp., trade name: Microtrac MT3300EXII), and the average particle size of the abrasive was 140 nm.

[0151] <Preparation of additives>

[0152] The following additives were prepared as components contained in the polishing liquid.

[0153] 1H-Indole-3-carboxylic acid

[0154] 1H-Indole-3-acetic acid

[0155] 1H-Indole-3-propionic acid

[0156] 1H-Indole-3-acetic acid methyl ester

[0157] 3-Methoxymethylindole

[0158] N-acetyl-DL-tryptophan (also known as rac-(αR * )-α-(Acetylamino)-1H-indole-3-propionic acid)

[0159] 5-Hydroxy-L-tryptophan

[0160] 5-Hydroxyindole-3-acetic acid

[0161] 5-Methoxyindole-3-acetic acid

[0162] 8-Hydroxyquinoline (Alias: 8-quinolinol)

[0163] 1H-Benzotriazole

[0164] 4-Quinolinecarboxylic acid

[0165] 2,6-Dihydroxyquinoline

[0166] Phthaloazine

[0167] L-Proline

[0168] Benzohydroxamic acid

[0169] Salicylaldehyde oxime

[0170] 4-Hydroxybenzoic acid

[0171] 1,3,5-Trihydroxybenzene dihydrate (also known as phloroglucinol dihydrate)

[0172] 2-Aminobenzaldehyde

[0173] L-Phenylalanine

[0174] 3-Hydroxy-2-pyridinecarboxylic acid (Alias: 3-hydroxypicolinic acid)

[0175] 5-Hydroxy-2-pyridinecarboxylic acid (Alias: 5-hydroxypicolinic acid)

[0176] 5-Amino-2-pyridinecarboxylic acid (Alias: 5-aminopicolinic acid)

[0177] 3-Pyridinecarboxylic acid (alias: nicotinic acid)

[0178] 6-Methyl-2-pyridinecarboxylic acid (Alias: 6-methylpicolinic acid)

[0179] 1H-Pyrrole-3-carboxylic acid

[0180] <Preparation of CMP slurry>

[0181] The polishing liquid was obtained by mixing the above-mentioned slurry, the additives of Tables 1 to 5, a nonionic polymer (polyglycerol, weight average molecular weight: 750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name: PGL#750), acyclic alcohol (3-methoxy-3-methyl-1-butanol) and deionized water. Based on the total mass of the polishing liquid, the content of the abrasive particles was 1.0 mass%, the content of the additives of Tables 1 to 5 was 0.10 mass%, the content of the nonionic polymer was 0.20 mass%, and the content of the acyclic alcohol was 8.96 mass%. For each polishing liquid, as acetic acid mixed when preparing the above-mentioned slurry, acetic acid in an amount corresponding to the content of each abrasive particle was contained. The average particle size of the abrasive particles in the polishing liquid of each example is the same as the average particle size of the abrasive particles in the above-mentioned slurry.

[0182] <Zeta potential measurement>

[0183] An appropriate amount of polishing liquid was placed in "DelsaNano C" manufactured by Beckman Coulter, Inc., and the temperature was measured twice at 25° C. The average value of the displayed zeta potential was obtained and used as the zeta potential. In each of the Examples and Comparative Examples, the zeta potential of the abrasive grains was positive.

[0184] <pH measurement>

[0185] The pH of the polishing liquid was measured under the following conditions. The results are shown in Tables 1 to 5.

[0186] Measurement temperature: 25℃

[0187] Measuring device: HORIBA, Ltd. product name: Model (D-71)

[0188] Determination method: Phthalate pH standard solution (pH: 4.01), neutral phosphate pH standard solution (pH: 6.86) and borate pH standard solution (pH: 9.18) were used as pH standard solutions. After the pH meter was calibrated at 3 points, the electrode of the pH meter was placed in the grinding liquid, and the pH was measured by the measurement device after it had stabilized for more than 2 minutes.

[0189] <Evaluation of dispersion stability of abrasive particles>

[0190] The polishing liquid just prepared was left to stand for 1 week (168 hours), and the average particle size of the abrasive particles after 3 hours and 1 week from the time of preparation was measured by the same method as the average particle size of the abrasive particles in the slurry. As the rate of change of the average particle size of the abrasive particles after 3 hours or 1 week, "[(average particle size in the polishing liquid after 3 hours or 1 week - average particle size of the abrasive particles in the slurry) / average particle size of the abrasive particles in the slurry] × 100" was calculated. The case where the rate of change of the average particle size of the abrasive particles after 1 week (and the rate of change of the average particle size of the abrasive particles after 3 hours) was 4% or less was judged as "A", the case where the rate of change of the average particle size of the abrasive particles after 1 week exceeded 4%, but the rate of change of the average particle size of the abrasive particles after 3 hours was less than 4% was judged as "B", and the case where the rate of change of the average particle size of the abrasive particles after 3 hours exceeded 4% was judged as "C". The results are shown in Tables 1 to 5.

[0191] <Evaluation of polishing characteristics>

[0192] Using the above-mentioned polishing liquid, the polishing characteristics were evaluated as follows.

[0193] (Evaluation wafer)

[0194] As evaluation wafers, a 200 mm diameter blanket wafer (BKW, purchased from ADVANTEC CO., LTD.) without a pattern and having a silicon oxide film on the surface and a wafer with a test pattern (PTW, manufactured by Hitachi, Ltd.) were prepared.

[0195] The initial film thickness of the silicon oxide film of the unpatterned blanket wafer was 1000 nm.

[0196] The wafer with the test pattern has a silicon oxide film with fine unevenness, and the convex part (Line part) has an initial step difference of about 5000nm higher than the concave part (Space part). From the state where the initial film thickness of the silicon oxide film is about 6000nm, the convex and concave shapes are formed by etching the concave part by about 5000nm. The wiring is a line pattern formed in a chip unit of 12mm×12mm, which is a line pattern with 30μm wide convex parts (Line part) and 570μm wide concave parts (Space part) parallel to each other (pitch: 600μm width, L / S=30 / 570μm, the ratio of the area of ​​the convex part based on the total area of ​​the concave part and the convex part: 5%).

[0197] (Polishing of silicon oxide film)

[0198] The evaluation wafer was ground using a grinding device (Applied Materials, Inc., trade name: Mirra3400). The evaluation wafer was placed on a holder having a substrate mounting adsorption pad. A porous urethane resin grinding pad (K-groove, DuPont (Dow) Company, model: IC-1010) was attached to a grinding plate with a diameter of 500 mm.

[0199] The holder was placed on the polishing pad with the polished surface of the evaluation wafer facing downward. The inner tube pressure, the fixing ring pressure, and the membrane pressure were set to 14 kPa, 21 kPa, and 14 kPa, respectively.

[0200] Then, the polishing liquid was dripped onto the polishing pad attached to the polishing platen at a flow rate of 200 mL / min, while the polishing platen and the evaluation wafer were respectively heated for 93 min. -1 and 87min -1 The polished surface was polished by rotating. The blanket wafer was polished for 30 seconds. The pattern wafer was polished for 60 seconds. Next, the polished evaluation wafer was thoroughly cleaned with pure water using a PVA brush (polyvinyl alcohol brush) and then dried.

[0201] (Evaluation of polishing characteristics)

[0202] Using an optical interference film thickness measuring device (manufactured by Nanometrics, Inc., trade name: AFT-5100), the film thickness change of the silicon oxide film before and after polishing was measured as shown below to obtain the polishing rate.

[0203] In the blanket wafer, the film thickness change was measured at a total of 41 points (20 points on both sides of the center point) at intervals of 5 mm from the center point in the diameter direction of the wafer (the next measurement point after the measurement point 95 mm from the center was set at 97 mm from the center). The film thickness change during the 30-second polishing time was measured at these 41 points, and the average value was obtained and used as the polishing rate of the blanket wafer.

[0204] In the pattern wafer, the film thickness variation at the convex part in the L / S=30μm / 570μm region was measured to obtain the polishing rate of the pattern wafer. The film thickness variation at the central part 1 of the convex part (line pattern) in the central chip unit (12mm×12mm) formed on the pattern wafer was measured.

[0205] [Table 1]

[0206]

[0207] [Table 2]

[0208]

[0209] [Table 3]

[0210]

[0211] [Table 4]

[0212]

[0213] [Table 5]

[0214]

[0215] Explanation of symbols

[0216] 10 - ILD film, 20 - wiring, 30 - silicon oxide film, 40 - contact plug, 100, 100a - substrate, D - step difference.

Claims

1. A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound and water. The abrasive grains include cerium-based particles, The nitrogen-containing compound comprises a compound A1 having a condensed ring, The fused ring has an aromatic 5-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 CMP polishing liquid according to claim 1, wherein An alkyl group substituted with at least one selected from the group consisting of a carboxyl group and a carboxylate group is bonded to the aromatic 5-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 CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound and water. The abrasive grains include cerium-based particles, The nitrogen-containing compound includes a compound A2 having a quinoline ring and one hydroxyl group bonded to the quinoline ring.

7. A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound and water. The abrasive grains include cerium-based particles, The nitrogen-containing compound includes 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: The hydroxyamide group is bonded to the aromatic ring.

10. A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound and water. The abrasive grains include cerium-based particles, The nitrogen-containing compound includes a compound A4 having a nitrogen-containing aromatic ring bonded to at least one selected from the group consisting of a hydroxyl group and an amino group.

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

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

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

14. The CMP polishing liquid according to any one of claims 1 to 12, wherein The pH is 3.00~7.

00.

15. A CMP polishing liquid kit, wherein: The components contained in the CMP polishing liquid according to any one of claims 1 to 12 are separated and stored into a first liquid and a second liquid, wherein the first liquid contains the abrasive grains and water, and the second liquid contains the nitrogen-containing compound and water. 16 . A polishing method comprising the step of polishing a surface to be polished using the CMP polishing liquid according to claim 1 .

17. The grinding method according to claim 16, wherein: The polished surface includes silicon oxide.

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