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

Abstract

A polishing liquid for CMP, which contains abrasive grains, a nitrogen-containing compound having an aromatic ring, and water, the abrasive grains containing cerium-based particles, and the Zeta potential of the abrasive grains being negative. And a polishing method including a step for polishing a surface to be polished using the polishing liquid for CMP.

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] When using abrasive grains to grind a surface to be grinded, it is required that the abrasive grains are not likely to remain on the surface to be grinded after grinding. Among them, silicon oxide of the grinding material has a tendency to have a negative zeta potential, so when using abrasive grains with a negative zeta potential to grind a surface to be grinded containing silicon oxide, the abrasive grains are not likely to remain on the surface to be grinded after grinding due to the electrostatic repulsion between the abrasive grains and the surface to be grinded. On the other hand, it is difficult to increase the grinding speed due to the electrostatic repulsion between the abrasive grains and the surface to be grinded, so when using abrasive grains with a negative zeta potential, it is sometimes difficult to achieve a high grinding speed for silicon oxide.

[0013] Furthermore, the CMP polishing liquid can be used to flatten the polished surface by polishing a pattern wafer having a concave-convex pattern composed of convex parts (e.g., Line parts) and concave parts (e.g., Space parts) to remove the convex parts. In this case, from the viewpoint of obtaining high flatness and shortening the polishing time required for flattening, it is sometimes required to achieve a high polishing rate ratio of silicon oxide at the convex parts of the pattern wafer having a concave-convex pattern relative to silicon oxide in a blanket wafer without a concave-convex pattern. However, when using abrasive grains having a negative zeta potential, it is sometimes difficult to achieve such a high polishing rate ratio due to the difficulty in increasing the polishing rate due to electrostatic repulsion between the abrasive grains and the convex parts.

[0014] One aspect of the present invention is to provide a CMP polishing liquid using abrasive particles having a negative zeta potential, the CMP polishing liquid being able to achieve a high polishing rate ratio of silicon oxide at a convex portion of a pattern wafer having a concave-convex pattern relative to silicon oxide in a blanket wafer having no 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.

[0015] Means for solving technical problems

[0016] The present invention relates to the following [1] to

[15] and the like in some aspects.

[0017] [1] A CMP polishing liquid comprising abrasive grains, a nitrogen-containing compound having an aromatic ring, and water, wherein the abrasive grains include cerium-based particles and have a negative zeta potential.

[0018] [2] The CMP polishing liquid according to [1], wherein

[0019] The cerium-based particles include cerium oxide.

[0020] [3] The CMP polishing liquid according to [1] or [2], wherein

[0021] The nitrogen-containing compound includes a compound having an amino group bonded to an aromatic ring.

[0022] [4] The CMP polishing liquid according to [3], wherein

[0023] The nitrogen-containing compound comprises anthranilic acid.

[0024] [5] The CMP polishing liquid according to any one of [1] to [4], wherein

[0025] The nitrogen-containing compound includes a compound having a hydroxyamide group bonded to an aromatic ring.

[0026] [6] The CMP polishing liquid according to [5], wherein

[0027] The nitrogen-containing compound comprises benzohydroxamic acid.

[0028] [7] The CMP polishing liquid according to any one of [1] to [6], wherein

[0029] The nitrogen-containing compound comprises an indole compound.

[0030] [8] The CMP polishing liquid according to [7], wherein

[0031] The nitrogen-containing compound comprises indoleacetic acid.

[0032] [9] The CMP polishing liquid according to any one of [1] to [8], wherein

[0033] The nitrogen-containing compound comprises a quinoline compound.

[0034]

[10] The CMP polishing liquid according to [9], wherein

[0035] The nitrogen-containing compound comprises quinaldic acid.

[0036]

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

[10] , wherein

[0037] The content of the nitrogen-containing compound is 0.001 to 5% by mass.

[0038]

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

[11] , wherein

[0039] The pH is 4.0~9.0.

[0040]

[13] A CMP polishing liquid kit, wherein:

[0041] The CMP polishing liquid according to any one of [1] to

[12] is stored by separating the constituent components 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]

[14] 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

[12] .

[0043]

[15] The grinding method according to

[14] , wherein:

[0044] The polished surface includes silicon oxide.

[0045] Effects of the Invention

[0046] According to one aspect of the present invention, there can be provided a CMP polishing liquid, which uses abrasive particles having a negative zeta potential, and the CMP polishing liquid can achieve a high polishing rate ratio of silicon oxide at the convex portion of a pattern wafer having a concave-convex pattern relative to silicon oxide in a blanket wafer without a concave-convex pattern. And, according to another aspect of the present invention, there can be provided a CMP polishing liquid kit for obtaining the CMP polishing liquid. In addition, according to another aspect of the present invention, there can be 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.

[0050] <Polishing fluid for CMP>

[0051] The CMP polishing liquid involved in this embodiment (hereinafter, simply referred to as "polishing liquid" depending on the situation) contains abrasive grains, a nitrogen-containing compound having an aromatic ring (hereinafter, referred to as "nitrogen-containing aromatic compound" depending on the situation) and water. The abrasive grains include cerium-based particles (particles containing cerium-based compounds), and the zeta potential of the abrasive grains is negative.

[0052] According to the polishing liquid involved in the present embodiment, a high polishing rate ratio of silicon oxide at the convex part of a pattern wafer having a concave-convex pattern (a concave-convex pattern composed of convex parts (e.g., Line parts) and concave parts (e.g., Space parts)) 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 part in the area of ​​Line / Space (L / S) = 20μm / 80μm ​​of the pattern wafer to silicon oxide in a blanket wafer without a concave-convex pattern can be achieved. According to 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 part in the area of ​​L / S = 20μm / 80μm ​​of the pattern wafer to silicon oxide in the blanket wafer can be, for example, 0.70 or more (preferably 0.90 or more, 1.00 or more, 1.50 or more, 1.70 or more, etc.). By obtaining a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer having the concavo-convex pattern to silicon oxide in the blanket wafer having no concavo-convex pattern, high flatness can be achieved as a characteristic capable of selectively polishing the convex portion.

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

[0054] That is, when abrasive grains having a negative zeta potential are used to polish a polished surface containing silicon oxide, it is sometimes difficult to achieve a high polishing rate for silicon oxide due to electrostatic repulsion between the abrasive grains and the polished surface. In particular, in a pattern wafer, it is easy to apply a high pressure to a convex portion, but it is sometimes difficult to obtain a polishing rate corresponding to the pressure applied to the convex portion.

[0055] On the other hand, according to the polishing liquid involved in this embodiment, by using a nitrogen-containing aromatic compound together with the cerium-based particles, the following effects can be obtained: the interaction between the cerium-based particles and the silicon oxide on the protrusions is easily enhanced (for example, the chemical reaction between the cerium-based particles in the polishing liquid and the silicon oxide on the protrusions (the reaction caused by the bonding of Si-O-Ce)) is easily promoted, and the absolute value of the negative charge of the polished surface containing silicon oxide is reduced, so that the electrostatic repulsion between the polishing particles and the polished surface is easily suppressed. Therefore, it is speculated that when polishing a patterned wafer, since a polishing speed corresponding to the pressure applied to the protrusions can be easily obtained, a high polishing speed of the silicon oxide on the protrusions can be achieved, and a high polishing speed ratio of the silicon oxide at the protrusions of the patterned wafer relative to the silicon oxide in the blanket wafer can be achieved.

[0056] According to the inventors' understanding, when using abrasive grains with negative Zeta potential, even if a high polishing rate of silicon oxide is achieved when polishing a blanket wafer without a concave-convex pattern, it is sometimes difficult to achieve a high polishing rate of silicon oxide on the convex portion when polishing a pattern wafer with a concave-convex pattern. Therefore, with respect to a polishing liquid using abrasive grains with negative Zeta potential, it is sometimes required to achieve a high polishing rate of silicon oxide on the convex portion when polishing a pattern wafer with a concave-convex pattern. According to one method of the polishing liquid involved in the present embodiment, a high polishing rate of silicon oxide on the convex portion can be achieved when polishing a pattern wafer with a concave-convex pattern, for example, a high polishing rate of silicon oxide on the convex portion can be achieved when polishing an area where Line / Space (L / S) = 20μm / 80μm ​​in a pattern wafer. According to one mode of the polishing liquid involved in this embodiment, in the evaluation method described in the examples described later, the polishing speed of the silicon oxide on the convex portion in the area of ​​L / S=20μm / 80μm ​​can be, for example, 100nm / min or more (preferably 150nm / min or more, 200nm / min or more, 250nm / min or more, 300nm / min or more, 350nm / min or more, etc.).

[0057] 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 when polishing an L / S=20μm / 80μm ​​region in 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 a polishing speed of silicon oxide in a blanket wafer, for example, 40nm / min or more (preferably 50nm / min or more, 80nm / min or more, 100nm / min or more, 150nm / min or more, 200nm / min or more, 230nm / min or more, etc.) can be obtained.

[0058] 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, 100nm / min or less (preferably 50nm / min or less, 30nm / min or less, 20nm / min or less, 15nm / min or less, etc.) can be obtained.

[0059] 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.

[0060] (Abrasive particles)

[0061] 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.

[0062] 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, and the like. 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=20μm / 80μm ​​region, etc.; the same below) and 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).

[0063] 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.

[0064] 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.

[0065] The Zeta potential (surface potential) of the abrasive particles in the polishing liquid is negative (Zeta potential is less than 0 mV). The Zeta potential of the abrasive particles can be below -1 mV, below -5 mV, below -10 mV, below -20 mV, below -30 mV, below -40 mV, below -45 mV, below -50 mV, or below -55 mV. The Zeta potential of the abrasive particles can be above -100 mV, above -90 mV, above -80 mV, above -70 mV, above -60 mV, above -55 mV, above -50 mV, or above -45 mV. From these viewpoints, the Zeta potential of the abrasive particles can be -100 mV or more and less than 0 mV, -80 mV or more and less than 0 mV, -60 mV or more and less than 0 mV, -100 mV to -20 mV, -80 mV to -20 mV, -60 mV to -20 mV, -100 mV to -40 mV, -80 mV to -40 mV, or -60 mV to -40 mV.

[0066] The zeta potential of the abrasive particles can be measured, for example, using a dynamic light scattering zeta potential measuring device (for example, manufactured by Beckman Coulter, Inc., trade name: Delsa Nano C). The zeta potential of the abrasive particles can be adjusted using additives. For example, by contacting the abrasive particles with an anionic dispersant, abrasive particles having a negative zeta potential can be obtained. Examples of anionic dispersants include polymers having at least one selected from the group consisting of carboxyl groups and carboxylate groups; ammonium dihydrogen phosphate, etc. Examples of polymers having at least one selected from the group consisting of carboxyl groups and carboxylate groups include ammonium polyacrylate, polyacrylic acid, copolymers of acrylic acid and acrylic acid alkyl, copolymers of acrylic acid and methacrylic acid, and salts thereof. 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 for silicon oxide at the convex portion of a pattern wafer relative to silicon oxide in a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the polishing liquid involved in this embodiment may include, as an anionic dispersant in contact with the abrasive particles, a polymer having at least one selected from the group consisting of a carboxyl group and a carboxylate group, and at least one selected from the group consisting of diammonium phosphate.

[0067] From the viewpoint of easily obtaining a high polishing speed of silicon oxide at the convex part of the pattern wafer and easily realizing high-speed polishing of silicon oxide in a blanket wafer without a concave-convex pattern, the average particle size of the abrasive grains can 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 can 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] The content of the abrasive grains can be in the following ranges based on the total mass of the polishing liquid from the viewpoint of balancing the polishing speed of silicon oxide at the convex portion of the pattern wafer and the dispersion stability of the abrasive grains. The content of the abrasive grains can be 0.01 mass %, 0.05 mass %, 0.1 mass %, 0.2 mass %, 0.3 mass %, 0.4 mass % or 0.5 mass %. The content of the abrasive grains can be 10 mass %, 5 mass %, 3 mass %, 2.5 mass %, 2 mass %, 1.8 mass %, 1.5 mass %, 1.2 mass %, 1 mass %, 0.8 mass %, 0.6 mass % or 0.5 mass %. From these viewpoints, the content of the abrasive grains may be 0.01 to 10 mass %, 0.01 to 3 mass %, 0.01 to 1 mass %, 0.05 to 10 mass %, 0.05 to 3 mass %, 0.05 to 1 mass %, 0.1 to 10 mass %, 0.1 to 3 mass % or 0.1 to 1 mass %.

[0070] (Nitrogen-containing aromatic compounds)

[0071] The polishing liquid according to the present embodiment contains a nitrogen-containing aromatic compound (a nitrogen-containing compound having an aromatic ring). The nitrogen-containing aromatic compound may have an aromatic ring containing a nitrogen atom or may have an aromatic ring not containing a nitrogen atom.

[0072] The nitrogen-containing aromatic compound may have a monocyclic aromatic ring or a polycyclic aromatic ring (a condensed ring formed by condensing two or more monocyclic aromatic rings, a condensed ring formed by condensing one or more monocyclic aromatic rings and one or more monocyclic non-aromatic rings, etc.).

[0073] Examples of the monocyclic aromatic ring include a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an imidazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, and a pyrazine ring.

[0074] Examples of the condensed ring formed by condensation of two or more monocyclic aromatic rings include a naphthalene ring, an anthracene ring, a benzofuran ring, an isobenzofuran ring, an indole ring, an isoindole ring, a benzothiophene ring, a benzimidazole ring, an indazole ring, a benzoxazole ring, a benzisoxazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, an acridine ring, a quinazoline ring, a cinnoline ring, a phthalazine ring, and a carbazole ring.

[0075] Examples of the condensed ring formed by condensation of one or more monocyclic aromatic rings and one or more monocyclic non-aromatic rings include an indane ring, a fluorene ring, and a tetralin ring.

[0076] Regarding nitrogen-containing aromatic compounds, from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide in the convex portion of the pattern wafer (the convex portion of the region of L / S=20μm / 80μm, etc.; the same below) relative to silicon oxide in the blanket wafer and from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, as an aromatic ring, a heterocyclic ring may be used, and a heterocyclic ring containing a nitrogen atom may be used. Regarding nitrogen-containing aromatic compounds, 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 and from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, as an aromatic ring, a carbon ring (non-heterocyclic ring) may be used, and a carbon ring (non-heterocyclic ring) not containing a nitrogen atom may be used. From the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to that in the blanket wafer and from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the nitrogen-containing aromatic compound may have at least one selected from the group consisting of a monocyclic aromatic ring and a condensed ring formed by condensation of two or more monocyclic aromatic rings, and may also have at least one selected from the group consisting of a benzene ring (monocyclic aromatic ring), an indole ring and a quinoline ring.

[0077] The aromatic ring may have a substituent or may not have a substituent (may be unsubstituted). The aromatic ring may have a single substituent or may have multiple substituents. The aromatic ring may have a substituent containing a nitrogen atom or may not have a substituent containing a nitrogen atom, may have a substituent not containing a nitrogen atom, or may not have a substituent not containing a nitrogen atom. As the substituent, substituted or unsubstituted alkyl, hydroxyl, carboxyl, carboxylate, aldehyde, alkoxy, amino, amide, hydroxyamide, nitro, cyano, mercapto, halo (fluoro, chloro, bromo, iodo, etc.) and the like can be cited. As the substituent replacing the hydrogen atom of the alkyl group, hydroxyl, carboxyl, carboxylate, aldehyde, alkoxy, amino, amide, hydroxyamide, nitro, cyano, mercapto, halo (fluoro, chloro, bromo, iodo, etc.) and the like can be cited.

[0078] 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 and easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the nitrogen-containing aromatic compound may include a compound having at least one selected from the group consisting of a carboxyl group, a carboxylate group, an amino group, and a hydroxyamide group, and as a substituent directly bonded to the aromatic ring, may also include a compound having at least one selected from the group consisting of a carboxyl group, a carboxylate group, an amino group, and a hydroxyamide group. The nitrogen-containing aromatic compound may include a compound not having at least one selected from the group consisting of a carboxyl group, a carboxylate group, an amino group, and a hydroxyamide group.

[0079] Examples of the nitrogen-containing aromatic compound include compounds having an amino group, compounds having a hydroxyamide group, indole compounds (compounds having an indole ring), quinoline compounds (compounds having a quinoline ring), pyridine compounds (compounds having a pyridine ring), and the like.

[0080] As the compound having an amino group, aniline, o-aminobenzoic acid, etc. can be cited. 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 and easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the compound having an amino group may include a compound having an amino group bonded to an aromatic ring (e.g., a monocyclic benzene ring), and may also include a compound having an amino group and at least one selected from the group consisting of a carboxyl group and a carboxylate group. As a functional group bonded to an aromatic ring (e.g., a monocyclic benzene ring), a compound having an amino group and at least one selected from the group consisting of a carboxyl group and a carboxylate group may be included.

[0081] Examples of the compound having a hydroxyamide group include benzohydroxamic acid, etc. 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 and easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the compound having a hydroxyamide group may include a compound having a hydroxyamide group bonded to an aromatic ring (e.g., a monocyclic benzene ring).

[0082] Examples of the indole compound include indole, indole acid (indoleacetic acid, indolepropionic acid, etc.), alkyl indole (methyl indole, etc.), phenyl indole, hydroxy indole, carboxy indole, alkoxy indole, amino indole, nitro indole, nitrilo indole, and chloro indole.

[0083] Examples of the quinoline compound include quinoline, quinoline alcohol, quinolinecarboxylic acid (quinaldic acid and the like), aminoquinoline, and mercaptoquinoline.

[0084] Examples of the pyridine compound include pyridine, hydroxypyridine, aminopyridine, carboxypyridine (picolinic acid, nicotinic acid, isonicotinic acid, etc.), hydroxypyridinecarboxylic acid (hydroxypicolinic acid), aminopyridinecarboxylic acid (aminopicolinic acid), and cyanopyridine.

[0085] 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 and the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, the nitrogen-containing aromatic compound may include at least one selected from the group consisting of a compound having an amino group, a compound having a hydroxyamide group, an indole compound and a quinoline compound, or may include at least one selected from the group consisting of a compound having an amino group bonded to an aromatic ring, a compound having a hydroxyamide group bonded to an aromatic ring, an indole compound and a quinoline compound, or may include at least one selected from the group consisting of anthranilic acid, benzohydroxamic acid, indoleacetic acid and quinaldic acid. That is, the nitrogen-containing aromatic compound may be a method of including a compound having an amino group bonded to an aromatic ring, a method of including anthranilic acid, a method of including a compound having a hydroxyamide group bonded to an aromatic ring, a method of including benzohydroxamic acid, a method of including an indole compound, a method of including indoleacetic acid, a method of including a quinoline compound or a method of including quinaldic acid. From the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portions of the pattern wafer to silicon oxide in the blanket wafer and easily achieving a high polishing rate of silicon oxide at the convex portions of the pattern wafer, the nitrogen-containing aromatic compound may include a compound other than the picolinic acid compound.

[0086] Based on the total mass of the polishing liquid, the content A can be within the following ranges, including the content of nitrogen-containing aromatic compounds, the content of compounds having an amino group bonded to an aromatic ring, the content of o-aminobenzoic acid, the content of compounds having a hydroxyamide group bonded to an aromatic ring, the content of benzohydroxamic acid, the content of indole compounds, the content of indoleacetic acid, the content of quinoline compounds or the content of quinaldine acid. From the viewpoint of easily achieving a high polishing speed ratio of silicon oxide at the convex portion of the pattern wafer relative to the silicon oxide in the blanket wafer, from the viewpoint of easily obtaining a high polishing speed of silicon oxide at the convex portion of the pattern wafer, and from the viewpoint of easily suppressing the polishing speed of silicon nitride, the content A can be greater than 0.0001 mass%, greater than 0.0005 mass%, greater than 0.001 mass%, greater than 0.003 mass%, greater than 0.005 mass%, greater than 0.008 mass%, greater than 0.01 mass%, greater than 0.015 mass%, greater than 0.02 mass%, greater than 0.025 mass%, greater than 0.03 mass%, greater than 0.035 mass%, greater than 0.04 mass%, greater than 0.045 mass% or greater than 0.05 mass%. 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, easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, easily suppressing the polishing rate of silicon nitride, and easily achieving excellent dispersion stability of the abrasive particles, the content A can be less than 5 mass%, less than 3 mass%, less than 1 mass%, less than 0.8 mass%, less than 0.5 mass%, less than 0.4 mass%, less than 0.3 mass%, or less than 0.2 mass%. , 0.1 mass % or less, 0.09 mass % or less, 0.08 mass % or less, 0.07 mass % or less, 0.06 mass % or less, 0.05 mass % or less, 0.045 mass % or less, 0.04 mass % or less, 0.035 mass % or less, 0.03 mass % or less, 0.025 mass % or less, 0.02 mass % or less, 0.015 mass % or less, 0.01 mass % or less, less than 0.01 mass %, 0.008 mass % or less or 0.005 mass % or less. From these viewpoints, the content A may be 0.0001 to 5 mass%, 0.0001 to 1 mass%, 0.0001 to 0.1 mass%, 0.0001 to 0.015 mass%, 0.0001 to 0.008 mass%, 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.015 mass%, 0.001 to 0.008 mass%, 0.008 to 5 mass%, 0.008 to 1 mass%, 0.008 to 0.1 mass%, 0.008 to 0.015 mass%, 0.015 to 5 mass%, 0.015 to 1 mass% or 0.015 to 0.1 mass%.The content of the nitrogen-containing aromatic compound is the total amount of the compounds belonging to the nitrogen-containing aromatic compound, and the content of the compound having an amino group bonded to an aromatic ring is the total amount of the compounds belonging to the compound having an amino group bonded to an aromatic ring, and the same applies to other similar expressions. The same applies to the following expressions.

[0087] As the mass ratio of the content of nitrogen-containing aromatic compounds to the content of abrasives (nitrogen-containing aromatic compounds / abrasives), the mass ratio of the content of compounds having amino groups bonded to aromatic rings to the content of abrasives (compounds having amino groups bonded to aromatic rings / abrasives), the mass ratio of the content of anthranilic acid to the content of abrasives (anthranilic acid / abrasives), the mass ratio of the content of compounds having hydroxyamide groups bonded to aromatic rings to the content of abrasives (compounds having hydroxyamide groups bonded to aromatic rings / abrasives), the mass ratio of the content of benzohydroxamic acid to the content of abrasives (benzohydroxamic acid / abrasives), the mass ratio of the content of indole compounds to the content of abrasives (indole compounds / abrasives), the mass ratio of the content of indoleacetic acid to the content of abrasives (indoleacetic acid / abrasives), the mass ratio of the content of quinoline compounds to the content of abrasives (quinoline compounds / abrasives), or the mass ratio of the content of quinaldic acid to the content of abrasives (quinaldic acid / abrasives), the mass ratio B may be within the following range. From the viewpoint of easily achieving a high polishing speed ratio of silicon oxide at the convex portion of the pattern wafer relative to the silicon oxide in the blanket wafer, from the viewpoint of easily obtaining a high polishing speed of silicon oxide at the convex portion of the pattern wafer, and from the viewpoint of easily suppressing the polishing speed of silicon nitride, the mass ratio B can be greater than 0.001, greater than 0.002, greater than 0.003, greater than 0.005, greater than 0.008, greater than 0.01, greater than 0.015, greater than 0.02, greater than 0.025, greater than 0.03, greater than 0.035, greater than 0.04, greater than 0.05, greater than 0.08 or greater than 0.1. From the viewpoint of easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to the silicon oxide in the blanket wafer, 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, from the viewpoint of easily suppressing the polishing rate of silicon nitride, and from the viewpoint of easily achieving excellent dispersion stability of the abrasive particles, the mass ratio B can be less than 1, less than 1, less than 0.8, less than 0.6, less than 0.5, less than 0.4, less than 0.3, less than 0.2, less than 0.1, less than 0.08, less than 0.05, less than 0.04, less than 0.035, less than 0.03, less than 0.025, less than 0.02, less than 0.015 or less.From these viewpoints, the mass ratio B may be 0.001 to 1, 0.001 to 0.3, 0.001 to 0.1, 0.001 to 0.05, 0.001 to 0.03, 0.001 to 0.015, 0.005 to 1, 0.005 to 0.3, 0.005 to 0.1, 0.005 to 0.05, 0.005 to 0.03, 0.005 to 0.015, 0.015 to 1, 0.015 to 0.3, 0.015 to 0.1, 0.015 to 0.05, 0.015 to 0.03, 0.03 to 1, 0.03 to 0.3, 0.03 to 0.1, or 0.03 to 0.05.

[0088] (Other additives)

[0089] The polishing liquid involved in this embodiment may further contain other additives (components not belonging to the above-mentioned components) according to the desired characteristics. Such components include nonionic polymers; cationic compounds; pH adjusters described below; polar solvents such as ethanol and acetone; cyclic monocarboxylic acids, etc.

[0090] 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.

[0091] (water)

[0092] 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.

[0093] (pH)

[0094] The pH of the polishing liquid involved in this embodiment can be within the following range. 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, easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, and easily suppressing the polishing rate of silicon nitride, the pH can be 12.0 or less, 11.0 or less, 10.5 or less, less than 10.5, 10.0 or less, less than 10.0, 9.5 or less, 9.0 or less, less than 9.0, 8.8 or less, 8.5 or less, 8.2 or less, 8.1 or less, 8.0 or less, less than 8.0, 7.8 or less, 7.6 or less, 7.5 or less, 7.2 or less, 7.0 or less, less than 7.0, 6.9 or less, 6.8 or less, 6.7 or less, 6.5 or less, 6.3 or less, 6.2 or less, 6.1 or less, 6.0 or less, less than 6.0, 5.9 or less, 5.7 or less, 5.5 or less, less than 5.5, 5.4 or less, 5.3 or less, 5.2 or less, 5.0 or less, less than 5.0, 4.9 or less. 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, 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, from the viewpoint of easily suppressing the polishing rate of silicon nitride, and from the viewpoint of easily achieving excellent dispersion stability of the abrasive particles, the pH can be above 4.0, above 4.5, above 4.9, above 5.0, exceeding 5.0, above 5.2, above 5.3, above 5.4, above 5.5, exceeding 5.5, above 5.7, above 5.9, above 6.0, exceeding 6.0, above 6.1, above 6.2, above 6.3, above 6.5, above 6.7, above 6.8, above 6.9, above 7.0, exceeding 7.0, above 7.2, above 7.5, above 7.6, above 7.8, above 8.0, exceeding 8.0 or above 8.1. From these viewpoints, the pH may be 4.0 to 12.0, 4.0 to 9.0, 4.0 to 8.0, 4.0 to 7.0, 4.0 to 6.0, 5.0 to 12.0, 5.0 to 9.0, 5.0 to 8.0, 5.0 to 7.0, 5.0 to 6.0, 6.0 to 12.0, 6.0 to 9.0, 6.0 to 8.0, 6.0 to 7.0, 7.0 to 12.0, 7.0 to 9.0, 7.0 to 8.0, 8.0 to 12.0 or 8.0 to 9.0. The pH may be measured by the method described in the embodiments. Regarding the lower limit of the pH, it is presumed that by making the pH within the above range, the zeta potential of the abrasive particles is easily maintained to be negative within a range in which the electrostatic repulsion between the abrasive particles and the polished surface is not excessively enhanced, and the electrostatic repulsion between the abrasive particles is easily maintained appropriately, so that excellent dispersion stability of the abrasive particles is easily achieved. However, the main reason is not limited to this content.

[0095] 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 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. Nitrogen-containing aromatic compounds, other additives, and the like may also 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.

[0096] <Preparation and use of polishing liquid>

[0097] 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.

[0098] (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 addition, during the preparation of the polishing liquid, a process of micronizing the abrasive grains can be performed 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.

[0099] The (b) concentrated type is diluted with water immediately before use so that the content of the components is the desired content. After dilution, stirring can be continued for an arbitrary period of time until the same liquid properties (pH, particle size of abrasive particles, etc.) and polishing properties (polishing rate 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.

[0100] 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.

[0101] The (c) multi-liquid type has the advantage of being able to avoid agglomeration of abrasive particles by being appropriately divided into various liquids (first liquid, second liquid, etc.) compared to the (b) concentrated type. Among them, 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. In the (c) multi-liquid type, the constituent components of the polishing liquid for CMP are divided into the first liquid and the second liquid for storage, the first liquid contains abrasive particles and water, and the second liquid contains a nitrogen-containing aromatic compound 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 particles in the first liquid, any acid or base may be formulated into the first liquid for pH adjustment.

[0102] (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. In addition, 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).

[0103] <Grinding method>

[0104] 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.

[0105] The polishing method involved in the present embodiment can use a polishing liquid with adjusted contents of various components, pH, etc., to flatten a substrate having a silicon oxide film on the surface by CMP technology. The polishing method involved in the present embodiment is suitable for polishing that requires high speed, high flatness and low polishing scratches, such as polishing of ILD films, and is suitable for polishing multiple ILD films in a short time. According to one mode of the polishing method involved in the present embodiment, the effect of increasing the polishing speed of silicon oxide in blanket wafers and the effect of increasing the in-plane uniformity can be effectively obtained. According to one mode of the polishing method involved in the present embodiment, since the polishing liquid involved in the present embodiment is used, it is possible to achieve excellent dispersion stability of abrasive particles, and reduce the generation of polishing scratches while achieving a sufficiently high polishing speed.

[0106] The grinding process can be a process of supplying the grinding liquid involved in the present embodiment between the substrate and the grinding component (grinding component, grinding pad, etc.), and grinding the substrate by the grinding component. The grinding method involved in the present embodiment is suitable for grinding a substrate having a silicon oxide film on the surface. Therefore, the ground surface can contain silicon oxide, and the grinding process can be a process of supplying the grinding liquid involved in the present embodiment between the silicon oxide film in the substrate having the silicon oxide film on the surface and the grinding component, and grinding the silicon oxide film by the grinding component.

[0107] 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 30μm or less than 20μm. The width of the convex parts in the concave-convex pattern can be more than 10μm or more than 20μm. 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 200μm or less than 100μm. 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 80μm or more than 100μm.

[0108] 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.

[0109] According to one mode of the polishing liquid involved in this embodiment, a high polishing rate can be achieved without relying on the concavo-convex shape of the polished surface to a large extent. Therefore, the polishing method using the polishing liquid can also be applied to a substrate that is difficult to achieve a high polishing rate by using a conventional polishing liquid method.

[0110] The grinding method involved in the present embodiment is suitable for flattening a surface to be ground with a step difference (concave and convex) on the surface. As a substrate having such a surface to be ground, for example, a semiconductor device for logic can be cited. In addition, the grinding method involved in the present embodiment is suitable for grinding a surface including a portion in which a concave portion or a convex portion is T-shaped or lattice-shaped when viewed from above. For example, the grinding method involved in the present embodiment can also grind a silicon oxide film on the surface of a semiconductor device (DRAM, flash memory, etc.) having a storage unit at a high speed. These are materials that are difficult to achieve a high grinding speed using the conventional CMP grinding liquid method, which means that one method of the grinding liquid involved in the present embodiment does not rely on the concave and convex shape of the surface to be ground to a large extent, and can achieve a high grinding speed.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] <Manufacturing method, etc.>

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] Example

[0126] Hereinafter, the present invention will be described in further detail based on examples, but the present invention is not limited to these examples.

[0127] <Production of cerium oxide powder>

[0128] 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.

[0129] <Preparation of slurry>

[0130] 15.0 kg of the cerium oxide powder obtained in the above and 84.85 kg of deionized water were placed in a container and mixed. Then, as a dispersant, 0.375 kg of an aqueous solution of ammonium polyacrylate (concentration 40 mass %, molecular weight: about 10,000) was added, and a cerium oxide mixed solution was obtained by stirring for 10 minutes. The cerium oxide mixed solution was delivered to other containers 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.

[0131] 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.

[0132] The slurry was diluted with pure water so as to obtain a content of abrasive particles having a scattering intensity suitable for the measurement range, thereby obtaining a sample for particle size measurement. The average particle size of the abrasive particles 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 particles was 140 nm.

[0133] <Preparation of CMP polishing slurry>

[0134] (Examples 1 to 11)

[0135] By mixing the above-mentioned slurry, various additives and deionized water according to the following steps, a polishing liquid containing 0.50 mass% of abrasive particles, additives (indoleacetic acid, benzohydroxamic acid, quinaldic acid or o-aminobenzoic acid) with the contents listed in the following Table 1 and 0.005 mass% of dispersant (ammonium polyacrylate mixed when preparing the above-mentioned slurry) was obtained (the remainder: deionized water).

[0136] Specifically, each additive was dissolved in deionized water to obtain an additive solution. Then, the slurry and the additive solution were mixed in equal amounts and stirred for 10 minutes to obtain a concentrated polishing liquid stock solution containing 5.00 mass % of abrasive grains based on the total mass. The polishing liquid stock solution contained 10 times the amount of abrasive grains and additives relative to the final polishing liquid content of 0.50 mass %.

[0137] The polishing liquid was obtained by diluting the polishing liquid stock solution by 10 times with deionized water. The average particle size of the abrasive particles in the polishing liquid of each example measured by the same method as the average particle size of the abrasive particles in the slurry was equal to the average particle size of the abrasive particles in the slurry.

[0138] (Comparative Example 1)

[0139] A polishing liquid containing 0.50 mass % of abrasive grains and 0.005 mass % of a dispersant (ammonium polyacrylate mixed when preparing the slurry) was obtained in the same manner as in Example except that no additive was used (the remainder: deionized water).

[0140] <Zeta potential measurement>

[0141] An appropriate amount of polishing liquid was added to "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, as shown in Table 1, the zeta potential of the abrasive grains was negative.

[0142] <pH measurement>

[0143] The pH of the polishing liquid was measured under the following conditions. The results are shown in Table 1.

[0144] Measurement temperature: 25℃

[0145] Measuring device: HORIBA, Ltd. product name: Model (D-71)

[0146] 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.

[0147] <Evaluation of dispersion stability of abrasive particles>

[0148] The polishing liquid just prepared was left to stand for 1 week (168 hours), and the average particle size of the abrasive particles after 1 week from the 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 1 week, "[(average particle size in the polishing liquid after 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 was 4% or less was judged as "A", and the case where the rate of change of the average particle size of the abrasive particles after 1 week exceeded 4% was judged as "B". The results are shown in Table 1.

[0149] <Evaluation of polishing characteristics>

[0150] (Preparation of evaluation wafers)

[0151] As blanket wafers (BKW), a φ200 mm unpatterned wafer having a silicon oxide film (SiO2, initial film thickness: 1000 nm) on the surface and a φ200 mm unpatterned wafer having a silicon nitride film (SiN, initial film thickness: 200 nm) on the surface were prepared.

[0152] As a pattern wafer (PTW), a wafer with a test pattern (model: Sematech 864, manufactured by ADVANTEC CO., LTD., φ200 mm) having a silicon oxide film (initial film thickness: 600 nm) with a concave-convex pattern on the surface was prepared. The convex part (Line part) has an initial step difference of 500 nm higher than the concave part (Space part), and considering the evaluation for shallow trench isolation, the convex part has a silicon nitride film (initial film thickness: 140 nm) as a barrier layer on the base of the silicon oxide film. The pattern wafer has a plurality of 20 mm × 20 mm chip units, and each chip unit has a plurality of 4 mm × 4 mm unit areas. The pattern wafer has an area including a parallel line pattern with a pitch of 100 μm wide and Line / Space (L / S) of 10 μm / 90 μm (convex density: 10%) to 90 μm / 10 μm (convex density: 90%) in 10 μm increments as a 4 mm × 4 mm unit area.

[0153] (Grinding Step)

[0154] 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.

[0155] 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.

[0156] 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. In the pattern wafer, according to the polishing speed evaluated by the blanket wafer, the time during which the silicon nitride film of the base of the silicon oxide film at the convex part of the L / S=20μm / 80μm ​​area was not exposed was set as the polishing time within the range of 20 to 60 seconds, and polishing was performed with this polishing time. Next, the polished evaluation wafer was thoroughly cleaned with pure water using a PVA brush (polyvinyl alcohol brush) and then dried.

[0157] (Evaluation of polishing speed)

[0158] Using an optical interferometric film thickness measuring device (manufactured by Nanometrics, Inc., trade name: AFT-5100), the film thickness change of the polished film before and after polishing was measured as shown below to obtain the polishing rate. In addition, the polishing rate ratio (PTW / BKW) of the silicon oxide at the convex portion of the pattern wafer to the silicon oxide in the blanket wafer was calculated. The results are shown in Table 1.

[0159] 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 of the measurement point 95 mm from the center was set to 97 mm from the center). The film thickness change for 30 seconds of polishing time was measured at these 41 points, and the average value was obtained and used as the polishing rate of the blanket wafer.

[0160] In the pattern wafer, the film thickness variation at the convex part of the L / S=20μm / 80μm ​​area was measured to obtain the polishing rate of the pattern wafer. In the central chip unit (20mm×20mm) in the pattern wafer, the film thickness variation at the central part 1 of a unit area (4mm×4mm) with L / S=20μm / 80μm ​​was measured.

[0161]

[0162] Explanation of symbols

[0163] 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 having an aromatic ring and water, The abrasive grains include cerium-based particles, The zeta potential of the abrasive particles is negative.

2. The CMP polishing liquid according to claim 1, wherein The cerium-based particles include cerium oxide.

3. The CMP polishing liquid according to claim 1, wherein The nitrogen-containing compound includes a compound having an amino group bonded to an aromatic ring.

4. The CMP polishing liquid according to claim 3, wherein The nitrogen-containing compound comprises anthranilic acid.

5. The CMP polishing liquid according to claim 1, wherein The nitrogen-containing compound includes a compound having a hydroxyamide group bonded to an aromatic ring.

6. The CMP polishing liquid according to claim 5, wherein The nitrogen-containing compound comprises benzohydroxamic acid.

7. The CMP polishing liquid according to claim 1, wherein The nitrogen-containing compound comprises an indole compound.

8. The CMP polishing liquid according to claim 7, wherein: The nitrogen-containing compound comprises indoleacetic acid.

9. The CMP polishing liquid according to claim 1, wherein The nitrogen-containing compound comprises a quinoline compound.

10. The CMP polishing liquid according to claim 9, wherein The nitrogen-containing compound comprises quinaldic acid.

11. The CMP polishing liquid according to claim 1, wherein The content of the nitrogen-containing compound is 0.001 to 5% by mass.

12. The CMP polishing liquid according to claim 1, wherein The pH is 4.0~9.

0.

13. A CMP polishing liquid kit, wherein: The CMP polishing liquid according to any one of claims 1 to 12 is stored as 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. 14 . A polishing method comprising the step of polishing a surface to be polished using the CMP polishing liquid according to claim 1 .

15. The grinding method according to claim 14, wherein: The polished surface includes silicon oxide.

Images