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

Abstract

A polishing liquid for CMP, which contains abrasive grains, an additive and water, and is characterized in that the abrasive grains contain cerium-based particles, the Zeta potential of the abrasive grains is negative, the additive contains (A1) a 4-pyrone-based compound represented by general formula (1), and the pH of the polishing liquid for CMP is 5.0 or more. A polishing liquid for CMP, which contains abrasive grains, an additive and water, the abrasive grains including cerium-based particles, the zeta potential of the abrasive grains being negative, the additive including (A2) a 2-picolinic acid compound, and the pH of the polishing liquid for CMP being 5.0 or more. In the formula, X11, X12, and X13 each independently represent a hydrogen atom or a monovalent substituent. # imgabs0 #

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, with the high performance of ultra-large-scale integrated circuit (ULSI) devices, the miniaturization technology on the extension line of the existing technology has reached its limit to achieve both high integration and high speed. Therefore, a technology that promotes the miniaturization of semiconductor elements and also achieves high integration in the vertical direction (i.e., multilayer wiring technology) is being developed.

[0003] In the process of manufacturing devices with multilayered wiring, CMP technology is one of the most important technologies. CMP technology is a technology that flattens 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. When there are unevenness on the surface of the substrate, problems such as inability to focus during the exposure process or inability to fully form a fine wiring structure may occur. In addition, CMP technology is also applicable to the process of manufacturing devices through plasma oxide films (BPSG, HDP-SiO 2 , p-TEOS, etc.) to form an element separation (separation between elements. STI: shallow trench isolation) area; a process of forming an ILD film (interlayer insulating film. An insulating film that electrically insulates metal parts (wiring, etc.) in the same layer from each other); a process of burying a film containing silicon oxide in the metal wiring and then flattening the plug (for example, Al·Cu plug), etc.

[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 pressing the substrate to the polishing pad while supplying a polishing liquid between the surface of the substrate and 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 to which the CMP technology described above is applied, especially 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, fine 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 the silica-based polishing liquid has been 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 abrasive grains are used 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. Here, silicon oxide of the grinded material tends to have a negative zeta potential, so when abrasive grains having a negative zeta potential are used 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, the electrostatic repulsion between the abrasive grains and the surface to be grinded makes it difficult to increase the grinding speed, so when abrasive grains having a negative zeta potential are used, it is sometimes difficult to achieve a high grinding speed for silicon oxide. Furthermore, according to the findings of the present inventors, when abrasive grains having a negative zeta potential are used, even if a high grinding speed for silicon oxide is achieved in the grinding of a blank wafer (Blanket Wafer) without a concave-convex pattern, it is sometimes difficult to achieve a high grinding speed for silicon oxide on the convex portion when grinding a patterned wafer having a concave-convex pattern composed of convex portions (e.g., Line portions) and concave portions (e.g., Space portions). Therefore, a CMP polishing liquid using abrasive grains having a negative zeta potential is required to achieve a high polishing rate for silicon oxide on the convex portions when polishing a pattern wafer having a concavo-convex pattern.

[0013] In addition, in a CMP polishing liquid using abrasive particles having a negative zeta potential, sedimentation of the abrasive particles may be observed over time after the CMP polishing liquid is prepared. Therefore, it is required to achieve excellent dispersion stability of the abrasive particles in a CMP polishing liquid using abrasive particles having a negative zeta potential.

[0014] One aspect of the present invention is to provide a CMP polishing liquid, which uses abrasive particles having a negative zeta potential, and the CMP polishing liquid achieves excellent dispersion stability of the abrasive particles, and when polishing a pattern wafer having a concave-convex pattern, a high polishing rate of silicon oxide on the convex portion can be achieved. Another aspect of the present invention is to provide a CMP polishing liquid set for obtaining the CMP polishing liquid. Furthermore, another aspect of the present invention is to provide a polishing method using the CMP polishing liquid or the CMP polishing liquid set.

[0015] Means for solving technical problems

[0016] The present invention is related to the following [1] to

[19] in several aspects.

[0017] [1] A CMP polishing liquid comprising abrasive grains, an additive and water, wherein the abrasive grains include cerium-based particles, the zeta potential of the abrasive grains is negative, the additive includes (A1) a 4-pyrone compound represented by the following general formula (1), and the pH of the CMP polishing liquid is 5.0 or above.

[0018]

[0019] Where, X 11 , X 12 and X 13 Each independently represents a hydrogen atom or a monovalent substituent.

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

[0021] The component (A1) includes at least one selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone, 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and 2-ethyl-3-hydroxy-4-pyrone.

[0022] [3] The CMP polishing liquid according to [1] or [2], wherein

[0023] The content of the component (A1) is 0.001 to 5% by mass.

[0024] [4] The CMP polishing liquid according to any one of [1] to [3], wherein

[0025] The additive further includes (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

[0026] [5] The CMP polishing liquid according to [4], wherein

[0027] The component (B) includes ethylenediaminetetraethanol.

[0028] [6] The CMP polishing liquid according to any one of [1] to [5], wherein

[0029] The pH of the CMP polishing liquid is 8.0 or less.

[0030] [7] A CMP polishing liquid comprising abrasive grains, an additive and water, wherein the abrasive grains include cerium-based particles, the zeta potential of the abrasive grains is negative, the additive includes (A2) a 2-pyridinecarboxylic acid compound, and the pH of the CMP polishing liquid is 5.0 or above.

[0031] [8] The CMP polishing liquid according to [7], wherein

[0032] The component (A2) contains 2-picolinic acid.

[0033] [9] The CMP polishing liquid according to [7] or [8], wherein

[0034] The component (A2) contains hydroxy 2-picolinic acid.

[0035]

[10] The CMP polishing liquid according to any one of [7] to [9], wherein

[0036] The component (A2) contains amino 2-picolinic acid.

[0037]

[11] The CMP polishing liquid according to any one of [7] to

[10] , wherein

[0038] The content of the component (A2) is 0.001 to 5% by mass.

[0039]

[12] The CMP polishing liquid according to any one of [7] to

[11] , wherein

[0040] The additive further includes (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

[0041]

[13] The CMP polishing liquid according to

[12] , wherein

[0042] The component (B) includes ethylenediaminetetraethanol.

[0043]

[14] The CMP polishing liquid according to any one of [7] to

[13] , wherein

[0044] The pH of the CMP polishing liquid is 8.0 or less.

[0045]

[15] A CMP polishing liquid kit, wherein:

[0046] The constituent components of the CMP polishing liquid according to any one of [1] to

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

[0047]

[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] .

[0048]

[17] The grinding method according to

[18] , wherein:

[0049] The polished surface includes silicon oxide.

[0050]

[18] A polishing method comprising the step of polishing a surface to be polished using a CMP polishing liquid obtained by mixing the first liquid and the second liquid in the CMP polishing liquid set according to

[15] .

[0051]

[19] The grinding method according to

[18] , wherein:

[0052] The polished surface includes silicon oxide.

[0053] Effects of the Invention

[0054] According to one aspect of the present invention, there is provided a CMP polishing liquid, which uses abrasive particles having a negative zeta potential, and the CMP polishing liquid achieves excellent dispersion stability of the abrasive particles, and when polishing a pattern wafer having a concave-convex pattern, a high polishing rate of silicon oxide on the convex portion can be achieved. Furthermore, according to another aspect of the present invention, there is provided a CMP polishing liquid set for obtaining the CMP polishing liquid. Furthermore, according to another aspect of the present invention, there is provided a polishing method using the CMP polishing liquid or the CMP polishing liquid set. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a schematic cross-sectional view showing a process of polishing the ILD film. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present invention will be described in detail.

[0057] In this specification, the numerical range represented by "~" indicates the 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 other stages. 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. Regarding "A or B", as long as any one of A and B is included, both can be included. If not otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. In the case where there are multiple substances equivalent to each component in the composition, if not otherwise specified, the content of each component in the composition represents the total amount of the multiple substances present in the composition. The term "layer" or "film" includes a shape structure formed on the entire surface when observed as a top view, as well as a shape structure formed on a part. 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.

[0058] <Polishing fluid for CMP>

[0059] The CMP polishing liquid involved in this embodiment (the first embodiment and the second embodiment. The same applies hereinafter) is a CMP polishing liquid (hereinafter sometimes referred to as "polishing liquid") containing abrasive grains, additives and water. The abrasive grains include cerium-based particles (particles containing cerium-based compounds), and the zeta potential of the abrasive grains is negative. The additive of the polishing liquid involved in the first embodiment includes (A1) a 4-pyrone compound represented by the following general formula (1) (component (A1)). The additive of the polishing liquid involved in the second embodiment includes (A2) a 2-pyridinecarboxylic acid compound (component (A2)). The additive of the polishing liquid involved in this embodiment may include component (A1) and component (A2). The pH of the polishing liquid involved in this embodiment is above 5.0.

[0060]

[0061] Where, X 11 , X 12 and X 13 Each independently represents a hydrogen atom or a monovalent substituent.

[0062] According to the polishing liquid involved in the present embodiment, in the process of polishing a pattern wafer having a concave-convex pattern composed of convex parts (e.g., Line parts) and concave parts (e.g., Space parts), a high polishing speed of silicon oxide on the convex parts can be achieved. For example, in the polishing of an area where Line / Space (L / S)=20μm / 80μm ​​in the pattern wafer, a high polishing speed of silicon oxide on the convex parts can be achieved. According to 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 on the convex parts in the area where L / S=20μm / 80μm, for example, 200nm / min or more (preferably 250nm / min or more, 300nm / min or more, 350nm / min or more, 400nm / min or more, 500nm / min or more, etc.) can be obtained.

[0063] The polishing liquid according to this embodiment can achieve excellent dispersion stability of abrasive particles. According to the polishing liquid according to this embodiment, the change rate of the average particle size of the abrasive particles after 3 hours in the evaluation method described in the examples below can be 4% or less, for example.

[0064] The main reason for these effects is not yet clear, but it is speculated as follows. However, the main reason is not limited to the following.

[0065] That is, when using abrasive grains having a negative zeta potential to grind a surface to be ground containing silicon oxide, it is sometimes difficult to achieve a high grinding speed for silicon oxide due to the electrostatic repulsion between the abrasive grains and the surface to be ground. On the other hand, according to the polishing liquid involved in this embodiment, by using the (A1) component or the (A2) component together with the cerium-based particles, the following effects can be obtained, namely, the interaction between the cerium-based particles and silicon oxide is easily enhanced (for example, the chemical reaction between the cerium-based particles in the polishing liquid and the silicon oxide on the protrusion (the reaction caused by the bonding of Si-O-Ce) is easily promoted), the absolute value of the negative charge of the surface to be ground containing silicon oxide is reduced, and the electrostatic repulsion between the abrasive grains and the surface to be ground is easily suppressed, etc. Therefore, when grinding a patterned wafer, it is easy to obtain a grinding speed corresponding to the pressure applied to the protrusion, so that a high grinding speed for the silicon oxide on the protrusion can be achieved.

[0066] Furthermore, when the component (A1) or the component (A2) is used together with the cerium-based particles, if the pH is low, it is sometimes impossible to achieve excellent dispersion stability of the abrasive particles. On the other hand, according to the polishing liquid involved in this embodiment, by having a pH of 5.0 or more, it is easy to maintain the zeta potential of the abrasive particles to be negative within a range where the electrostatic repulsion between the abrasive particles and the polished surface is not excessively enhanced, and it is easy to appropriately maintain the electrostatic repulsion between the abrasive particles, thereby achieving excellent dispersion stability of the abrasive particles.

[0067] The polishing liquid can be used to flatten the polished surface, which is achieved by polishing a pattern wafer having a concave-convex pattern to remove the convex portion. In this case, from the perspective 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 portion of the pattern wafer having a concave-convex pattern relative to silicon oxide in the non-patterned wafer without the concave-convex pattern. However, when using abrasive particles with a negative zeta potential, it is sometimes difficult to achieve such a high polishing rate ratio due to the electrostatic repulsion between the abrasive particles and the convex portion, which makes it difficult to increase the polishing rate.

[0068] According to one mode of the polishing liquid involved in the present embodiment, a high polishing rate ratio of silicon oxide at the convex part of the pattern wafer with a concave-convex pattern to silicon oxide in a non-patterned 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 Line / Space (L / S) = 20μm / 80μm ​​region of the pattern wafer to silicon oxide in a non-patterned 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 part in the region of L / S = 20μm / 80μm ​​of the pattern wafer to silicon oxide in the non-patterned wafer can be, for example, 0.70 or more (preferably 0.90 or more, 1.00 or more, 1.50 or more, 2.00 or more, etc.) can be obtained. By obtaining a high polishing rate ratio of silicon oxide at the convex part of the pattern wafer with a concave-convex pattern to silicon oxide in a non-patterned wafer without a concave-convex pattern, high flatness can be achieved as a characteristic that can selectively polish the convex part.

[0069] According to one mode of the polishing liquid involved in the present embodiment, high-speed polishing of silicon oxide in a patternless wafer without a concave-convex pattern can be achieved, and a high polishing speed of silicon oxide in a convex portion when polishing a L / S=20μm / 80μm ​​region in a patterned wafer 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, as a polishing speed of silicon oxide in a patternless 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, 300nm / min or more, etc.) can be obtained.

[0070] 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 mode 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 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 nitride in the patternless wafer, for example, 100nm / min or less (preferably 50nm / min or less, 30nm / min or less, 10nm / min or less, 5nm / min or less, etc.) can be obtained.

[0071] 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 while suppressing the aggregation of abrasive grains and the generation of polishing scratches, and high flatness can be obtained.

[0072] (Abrasive particles)

[0073] 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 are easily reduced, and a high polishing rate of silicon oxide on the convex portion of the pattern wafer is obtained.

[0074] Cerium compounds of 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 at 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 CeO 2 (Cerium (IV) oxide, Cerium dioxide), Ce 2 O 3 (Cerium(III) oxide).

[0075] 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 active surfaces appearing one after another, and can maintain a high polishing rate of silicon oxide at the convex portion of the pattern wafer.

[0076] As a method for producing cerium oxide particles, a calcination method and an oxidation method based on hydrogen peroxide or the like can be cited. When calcination is performed, 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 the like or wet crushing based on a planetary bead mill or the like 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.

[0077] 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 may 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 may 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 greater than -100 mV and less than 0 mV, greater than -80 mV and less than 0 mV, greater than -60 mV 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.

[0078] 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., product name: Delsa Nano C). The zeta potential of the abrasive particles can be adjusted using additives. For example, by bringing an anionic dispersant into contact with the abrasive particles, 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 alkyl acrylates, 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 patterned wafer, from the viewpoint of easily achieving a high polishing rate ratio for silicon oxide at the convex portion of a patterned wafer relative to silicon oxide in a non-patterned 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.

[0079] 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 patternless wafer without a concave-convex pattern, the average particle size of the abrasive particles 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 particles 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.

[0080] The "average particle size of abrasive grains" refers to the central value of the volume distribution obtained by measuring a sample in which abrasive grains are dispersed using a particle size distribution measuring device (for example, 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, a sample is prepared by dispersing the abrasive grains in water in such a manner that the content of the abrasive grains is adjusted to have a scattering intensity within a range suitable for measurement, and the sample is mounted on 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 is adjusted in such a manner that the content of the abrasive grains having a scattering intensity within a range suitable for measurement is obtained to prepare a sample, and the sample can be used and measured by the same method. By adjusting the average particle size of the abrasive grains, a high polishing speed and low scratch characteristics of silicon oxide corresponding to the particle size of the abrasive grains can be effectively obtained.

[0081] From the viewpoint of excellent balance between the polishing speed of silicon oxide at the convex part of the pattern wafer and the dispersion stability of the abrasive grains, the content of the abrasive grains can be within the following range based on the total mass of the polishing liquid. 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 %, 0.5 mass %, 0.6 mass %, 0.8 mass %, 1 mass %, 1.2 mass %, 1.5 mass %, 1.8 mass %, or 2 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 particles can 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%, 0.1 to 1 mass%, 0.8 to 10 mass% or 0.8 to 3 mass%.

[0082] (additive)

[0083] [Component (A1): 4-pyrone compound]

[0084] The additive of the polishing liquid involved in the first embodiment includes a 4-pyrone compound represented by general formula (1) (hereinafter, sometimes simply referred to as "4-pyrone compound") as component (A1). It is speculated that by using the 4-pyrone compound, the interaction between the polishing liquid and silicon oxide is enhanced, thereby facilitating the improvement of the polishing rate.

[0085] The 4-pyrone compound is a compound represented by the following general formula (1), and is a compound having a structure in which a hydroxyl group is bonded to a carbon atom adjacent to the carbon atom of the carbonyl group. The "4-pyrone compound" is a heterocyclic compound having an oxy group and a carbonyl group, and having a γ-pyrone ring (6-membered ring) in which the carbonyl group is located at the 4th position relative to the oxy group. In the 4-pyrone compound, a hydroxyl group is bonded to a carbon atom adjacent to a carboxyl group in the γ-pyrone ring, and substituents other than hydrogen atoms may be substituted on other carbon atoms.

[0086]

[0087] Where, X 11 , X 12 and X 13Each independently represents a hydrogen atom or a monovalent substituent. Examples of the monovalent substituent include an aldehyde group, a hydroxyl group, a carboxyl group, a carboxylate group, a sulfonic acid group, a phosphoric acid group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, a nitro group, a hydrazine group, an alkyl group (e.g., an alkyl group having 1 to 8 carbon atoms), an aryl group (e.g., an aryl group having 6 to 12 carbon atoms), and an alkenyl group (e.g., an alkenyl group having 1 to 8 carbon atoms). The alkyl group, aryl group, and alkenyl group may be substituted by OH, COOH, Br, Cl, I, NO, etc. 2 Having a monovalent substituent as X 11 , X 12 and X 13 In the case of 11 and X 12 Can be a substituent. 11 , X 12 and X 13 At least two of them may be hydrogen atoms.

[0088] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the patterned wafer relative to silicon oxide in the non-patterned wafer, and easily achieving excellent dispersion stability of the abrasive particles, the 4-pyrone-based compound may include a compound selected from 3-hydroxy-2-methyl-4-pyrone (also known as 3-hydroxy-2-methyl-4H-pyran-4-one, maltol), 5-hydroxy-2-(hydroxymethyl)-4-pyrone (also known as 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one, kojic acid (kojic acid) The invention also includes at least one selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone and 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and 3-hydroxy-2-methyl-4-pyrone. The 4-pyrone-based compounds can be used alone or in combination of two or more.

[0089] The 4-pyrone compound may be a water-soluble compound. By using a compound having high solubility in water, a desired amount of additives can be well dissolved in the polishing liquid, and the effect of improving the polishing speed and the dispersion stability of the abrasive particles can be achieved to a higher level. The solubility of the 4-pyrone compound in 100 g of water at room temperature (25° C.) may be 0.001 g or more, 0.005 g or more, 0.01 g or more, or 0.05 g or more. The upper limit of the solubility is not particularly limited.

[0090] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the content of the 4-pyrone compound can be within the following range based on the total mass of the polishing liquid. The content of the 4-pyrone compound can be 0.001 mass % or more, 0.003 mass % or more, 0.005 mass % or more, 0.008 mass % or more, 0.01 mass % or more, 0.02 mass % or more, 0.03 mass % or more, 0.04 mass % or more, 0.05 mass % or more, 0.06 mass % or more, 0.08 mass % or more, 0.1 mass % or more, 0.12 mass % or more, 0.15 mass % or more, 0.18 mass % or more, or 0.2 mass % or more. The content of 4-pyrone compounds may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.18% by mass or less, 0.15% by mass or less, 0.12% by mass or less, 0.1% by mass or less, 0.08% by mass or less, 0.06% by mass or less, 0.05% by mass or less, 0.04% by mass or less, 0.03% by mass or less, 0.02% by mass or less, 0.01% by mass or less, less than 0.01% by mass, 0.008% by mass or less, or 0.005% by mass or less. From these viewpoints, the content of the 4-pyrone compound can be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.3 mass%, 0.02 to 0.1 mass% or 0.02 to 0.05 mass%.

[0091] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the mass ratio A1 of the content of the 4-pyrone compound to the content of the abrasive grains (4-pyrone compound / abrasive grains) can be within the following range. The mass ratio A1 can be 0.001 or more, 0.002 or more, 0.003 or more, 0.005 or more, 0.008 or more, 0.01 or more, 0.02 or more, 0.025 or more, 0.03 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.15 or more, 0.18 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, or 0.4 or more. The mass ratio A1 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.18 or less, 0.15 or less, 0.12 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.01 or less, 0.008 or less, 0.005 or less, or 0.003 or less. From these viewpoints, the mass ratio A1 may be 0.001 to 1, 0.001 to 0.5, 0.001 to 0.2, 0.001 to 0.1, 0.01 to 1, 0.01 to 0.5, 0.01 to 0.2, 0.01 to 0.1, 0.1 to 1, 0.1 to 0.5, or 0.1 to 0.2.

[0092] [Component (A2): 2-picolinic acid compound]

[0093] The additive of the polishing liquid according to the second embodiment includes a 2-picolinic acid compound as the component (A2). It is presumed that the use of the component (A2) enhances the interaction between the polishing liquid and silicon oxide, thereby facilitating an increase in the polishing rate.

[0094] As the 2-pyridinecarboxylic acid compound, at least one selected from the group consisting of 2-pyridinecarboxylic acid (a compound having a pyridine ring and a carboxyl group bonded to the 2-position of the pyridine ring) and 2-pyridinecarboxylic acid derivatives can be used. The 2-pyridinecarboxylic acid derivative can be a compound having a pyridine ring, a carboxyl group bonded to the 2-position of the pyridine ring, and a substituent bonded to a position other than the 2-position of the pyridine ring, or a compound having a pyridine ring and a carboxylate group bonded to the 2-position of the pyridine ring (the compound may have a substituent bonded to a position other than the 2-position of the pyridine ring). As the 2-pyridinecarboxylic acid derivative, 2-pyridinecarboxylate (a compound having a pyridine ring and a carboxylate group bonded to the 2-position of the pyridine ring) can be used, or a compound having a pyridine ring, a carboxyl group or a carboxylate group bonded to the 2-position of the pyridine ring, and a substituent bonded to a position other than the 2-position of the pyridine ring can be used. Examples of the carboxylate group include functional groups in which the hydrogen atom of the carboxyl group is substituted with a metal atom (sodium atom, potassium atom, etc.). Examples of the substituent bonded to a position other than the 2-position in the pyridine ring include a hydroxyl group, an amino group, an alkyl group, and a vinyl group.

[0095] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the pattern wafer, easily achieving a high polishing rate ratio of silicon oxide at the convex portion of the pattern wafer relative to silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the 2-pyridine carboxylic acid compound may include at least one selected from the group consisting of 2-pyridine carboxylic acid, hydroxy 2-pyridine carboxylic acid, amino 2-pyridine carboxylic acid, and their salts, and may also include at least one selected from the group consisting of 2-pyridine carboxylic acid, 3-hydroxy 2-pyridine carboxylic acid, 3-amino 2-pyridine carboxylic acid, 5-hydroxy 2-pyridine carboxylic acid, 5-amino 2-pyridine carboxylic acid, and their salts. The 2-pyridine carboxylic acid compound may be a mode comprising at least one selected from the group consisting of 2-pyridine carboxylic acid and its salts, a mode comprising 2-pyridine carboxylic acid, a mode comprising at least one selected from the group consisting of hydroxy 2-pyridine carboxylic acid and its salts, a mode comprising hydroxy 2-pyridine carboxylic acid, a mode comprising at least one selected from the group consisting of amino 2-pyridine carboxylic acid and its salts, or a mode comprising amino 2-pyridine carboxylic acid.

[0096] The content A, as the content of the 2-picolinic acid compound, the content of 2-picolinic acid, the content of hydroxy 2-picolinic acid or the content of amino 2-picolinic acid, can be within the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, easily achieving a high polishing rate ratio for silicon oxide at the convex portion of the patterned wafer relative to silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The content A may be 0.0001% by mass or more, 0.0005% by mass or more, 0.001% by mass or more, 0.003% by mass or more, 0.005% by mass or more, 0.008% by mass or more, 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.055% by mass or more, 0.06% by mass or more, 0.07% by mass or more, 0.08% by mass or more, 0.09% by mass or more, or 0.1% by mass or more. The content A may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, 0.09% by mass or less, 0.08% by mass or less, 0.07% by mass or less, 0.06% by mass or less, 0.055% by mass or less, 0.05% by mass or less, 0.04% by mass or less, 0.03% by mass or less, 0.02% by mass or less, 0.01% by mass or less, less than 0.01% by mass, 0.008% by mass or less, or 0.005% by mass or less. From these viewpoints, the content A may be 0.0001 to 5 mass%, 0.0001 to 1 mass%, 0.0001 to 0.3 mass%, 0.0001 to 0.08 mass%, 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.08 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.08 mass%, 0.05 to 5 mass%, 0.05 to 1 mass%, 0.05 to 0.3 mass%, or 0.05 to 0.08 mass%.

[0097] The mass ratio A2, as the mass ratio of the content of 2-picolinic acid compound to the content of abrasive grains (2-picolinic acid compound / abrasive grains), the mass ratio of the content of 2-picolinic acid to the content of abrasive grains (2-picolinic acid / abrasive grains), the mass ratio of the content of hydroxy-2-picolinic acid to the content of abrasive grains (hydroxy-2-picolinic acid / abrasive grains) or the mass ratio of the content of amino-2-picolinic acid to the content of abrasive grains (amino-2-picolinic acid / abrasive grains), can be within the following ranges from the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, easily achieving a high polishing rate ratio for silicon oxide at the convex portion of the patterned wafer relative to silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The mass ratio A2 may be 0.001 or more, 0.002 or more, 0.003 or more, 0.005 or more, 0.008 or more, 0.01 or more, 0.02 or more, 0.025 or more, 0.0275 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.08 or more, or 0.1 or more. The mass ratio A2 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.0275 or less, 0.025 or less, 0.02 or less, 0.01 or less, 0.008 or less, 0.005 or less, or 0.003 or less. From these viewpoints, the mass ratio A2 may be 0.001 to 1, 0.001 to 0.3, 0.001 to 0.1, 0.001 to 0.03, 0.003 to 1, 0.003 to 0.3, 0.003 to 0.1, 0.003 to 0.03, 0.01 to 1, 0.01 to 0.3, 0.01 to 0.1, or 0.01 to 0.03.

[0098] [Component (B): nitrogen-containing hydroxyalkyl compound]

[0099] The additive of the polishing liquid involved in this embodiment may include a compound having two or more nitrogen atoms bonded with a hydroxyalkyl group (a nitrogen-containing hydroxyalkyl compound; wherein, the compound belonging to the (A1) component is excluded) as the (B) component. By using the (B) component to enhance the interaction between the polishing liquid and the convex silicon oxide in the concave-convex pattern, a high polishing rate of the convex silicon oxide is easily obtained, and the polishing rate of silicon nitride that can be used as a barrier layer material is easily suppressed. In the (B) component, the hydroxyalkyl group is directly bonded to the nitrogen atom, and the hydroxyl group is directly bonded to the alkyl group directly bonded to the nitrogen atom. In the (B) component, as the hydroxyalkyl group bonded to the nitrogen atom, an alkyl group having no substituent other than the hydroxyl group can be used.

[0100] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, component (B) may include a compound having a nitrogen atom bonded to two hydroxyalkyl groups, or may include a compound having two or more nitrogen atoms bonded to two hydroxyalkyl groups.

[0101] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the number of nitrogen atoms in one molecule of the component (B) may be 2 to 5, 2 to 4, or 2 to 3. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the number of hydroxyl groups in one molecule of the component (B) may be 2 to 6, 2 to 5, 2 to 4, 3 to 6, 3 to 5, 3 to 4, 4 to 6, or 4 to 5.

[0102] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the component (B) may have a hydroxyalkyl group having 1 to 4, 2 to 4, 3 to 4, 1 to 3, 2 to 3, or 1 to 2 carbon atoms as the hydroxyalkyl group bonded to the nitrogen atom. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the component (B) may have a hydroxyalkyl group having 1 to 3 or 1 to 2 hydroxy groups as the hydroxyalkyl group bonded to the nitrogen atom.

[0103] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the protrusions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, component (B) may have an alkylene group between two nitrogen atoms bonded to a hydroxyalkyl group, and the number of carbon atoms of the alkylene group may be 1 to 4, 2 to 4, 1 to 3, 2 to 3, or 1 to 2.

[0104] From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the protrusions of a patterned wafer, easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and easily suppressing the polishing rate for silicon nitride, the component (B) may include a compound represented by the following general formula (I).

[0105]

[0106] [wherein n is an integer greater than 1, R 11 , R 12 , R13 and R 14 Each independently represents a hydrogen atom or an organic group, R 11 and R 12 One or both of them are hydroxyalkyl, R 13 and R 14 One or both of them are hydroxyalkyl.]

[0107] n is the number of carbon atoms of the alkylene group between two nitrogen atoms bonded to the hydroxyalkyl group, and may be within the above range. The organic group may be a substituted or unsubstituted alkyl group, a hydroxyalkyl group, or a group having a nitrogen atom bonded to the hydroxyalkyl group. Examples of substituents for the alkyl group include hydroxyl, carboxyl, amino, sulfonic acid, and nitro groups. 11 , R 12 , R 13 or R 14 In the case of a hydroxyalkyl group, the number of carbon atoms of the hydroxyalkyl group as the number of carbon atoms of the hydroxyalkyl group bonded to the nitrogen atom may be within the above range.

[0108] Component (B) includes ethylenediaminetetraethanol (THEED: 2,2',2",2"'-ethylenediaminetetraethanol (also known as N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine), ethylenediaminetetrapropanol (EDTP: 1,1',1",1"'-ethanedinitriletetra-2-propanol (also known as N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine), and N,N,N',N",N"-penta(2-hydroxypropyl)diethylenetriamine. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the (B) component may include at least one selected from the group consisting of ethylenediaminetetraethanol and ethylenediaminetetrapropanol, and may also include ethylenediaminetetraethanol. From the viewpoint of easily obtaining a high polishing rate for silicon oxide at the convex portion of the patterned wafer, easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the (B) component may include a compound without a carboxyl group.

[0109] From the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride, the molecular weight of the component (B) may be within the following range. The molecular weight of the component (B) may be 50 or more, 60 or more, 80 or more, 100 or more, 120 or more, 140 or more, 150 or more, 160 or more, 180 or more, 200 or more, 220 or more, or 230 or more. The molecular weight of the component (B) may be 1000 or less, less than 1000, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 350 or less, 300 or less, 280 or less, 250 or less, less than 250, or 240 or less. From these viewpoints, the molecular weight of the component (B) may be 50-1000, 50-500, 50-300, 50-250, 100-1000, 100-500, 100-300, 100-250, 200-1000, 200-500, 200-300, or 200-250.

[0110] In the polishing liquid involved in the first embodiment, the content B1 as the content of the (B) component or the content of ethylenediaminetetraethanol can be within the following ranges based on the total mass of the polishing liquid from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving a high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The content B1 can be 0.001 mass % or more, 0.003 mass % or more, 0.005 mass % or more, 0.008 mass % or more, or 0.009 mass % or more. The content B1 can be 5 mass % or less, 3 mass % or less, 1 mass % or less, 0.5 mass % or less, 0.1 mass % or less, 0.05 mass % or less, 0.03 mass % or less, 0.01 mass % or less, or 0.009 mass % or less. From these viewpoints, the content B1 may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.01 mass%, 0.003 to 5 mass%, 0.003 to 1 mass%, 0.003 to 0.1 mass%, 0.003 to 0.01 mass%, 0.005 to 5 mass%, 0.005 to 1 mass%, 0.005 to 0.1 mass%, or 0.005 to 0.01 mass%.

[0111] In the polishing liquid involved in the second embodiment, the content B2 as the content of the (B) component or the content of ethylenediaminetetraethanol can be within the following range based on the total mass of the polishing liquid from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving a high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The content B2 can be 0.001 mass % or more, 0.005 mass % or more, 0.01 mass % or more, 0.015 mass % or more, 0.02 mass % or more, 0.025 mass % or more, 0.03 mass % or more, 0.035 mass % or more, 0.04 mass % or more, 0.045 mass % or more, 0.05 mass % or more, 0.055 mass % or more, 0.06 mass % or more, 0.065 mass % or more, 0.07 mass % or more, or 0.075 mass % or more. The content B2 may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, 0.09% by mass or less, 0.085% by mass or less, 0.08% by mass or less, 0.075% by mass or less, 0.07% by mass or less, 0.065% by mass or less, or 0.06% by mass or less. From these viewpoints, the content B2 may be 0.001 to 5% by mass, 0.001 to 1% by mass, 0.001 to 0.1% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.1% by mass, 0.05 to 5% by mass, 0.05 to 1% by mass, or 0.05 to 0.1% by mass.

[0112] In the polishing liquid involved in the first embodiment, the mass ratio B11 as the mass ratio of the content of the (B) component to the content of the abrasive grains ((B) component / abrasive grains) or the mass ratio of the content of ethylenediaminetetraethanol to the content of the abrasive grains (ethylenediaminetetraethanol / abrasive grains) can be within the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The mass ratio B11 can be greater than 0.0001, greater than 0.0005, greater than 0.001, greater than 0.002, greater than 0.003, greater than 0.004, or greater than 0.0045. The mass ratio B11 can be less than 1, less than 0.8, less than 0.5, less than 0.3, less than 0.1, less than 0.08, less than 0.05, less than 0.03, less than 0.01, less than 0.008, less than 0.005, or less than 0.0045. From these viewpoints, the mass ratio B11 may be 0.0001 to 1, 0.0001 to 0.1, 0.0001 to 0.01, 0.001 to 1, 0.001 to 0.1, 0.001 to 0.01, 0.003 to 1, 0.003 to 0.1, or 0.003 to 0.01.

[0113] In the polishing liquid involved in the second embodiment, the mass ratio B21 as the mass ratio of the content of the (B) component to the content of the abrasive grains ((B) component / abrasive grains) or the mass ratio of the content of ethylenediaminetetraethanol to the content of the abrasive grains (ethylenediaminetetraethanol / abrasive grains) can be within the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The mass ratio B21 can be greater than 0.001, greater than 0.005, greater than 0.01, greater than 0.015, greater than 0.02, greater than 0.025, greater than 0.03, or greater than 0.035. The mass ratio B21 can be less than 1, less than 0.5, less than 0.3, less than 0.1, less than 0.08, less than 0.05, less than 0.045, less than 0.04, less than 0.035, or less than 0.03. From these viewpoints, the mass ratio B21 may be 0.001 to 1, 0.001 to 0.1, 0.001 to 0.05, 0.01 to 1, 0.01 to 0.1, 0.01 to 0.05, 0.03 to 1, 0.03 to 0.1, or 0.03 to 0.05.

[0114] In the polishing liquid involved in the first embodiment, the mass ratio B12 as the mass ratio of the content of the (B) component to the content of the (A1) component ((B) component / (A1) component) or the mass ratio of the content of the ethylenediaminetetraethanol to the content of the (A1) component (ethylenediaminetetraethanol / (A1) component) can be within the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The mass ratio B12 can be greater than 0.01, greater than 0.05, greater than 0.1, greater than 0.3, greater than 0.5, greater than 0.7, greater than 0.8, or greater than 0.9. The mass ratio B12 can be less than 10, less than 8, less than 5, less than 4, less than 3, less than 2.5, less than 2, less than 1.5, less than 1, less than 1, or less than 0.9. From these viewpoints, the mass ratio B12 may be 0.01-10, 0.01-5, 0.01-1, 0.1-10, 0.1-5, 0.1-1, 0.5-10, 0.5-5, or 0.5-1.

[0115] In the polishing liquid involved in the second embodiment, the mass ratio B22 as the mass ratio of the content of the (B) component to the content of the (A2) component ((B) component / (A2) component) or the mass ratio of the content of the ethylenediaminetetraethanol to the content of the (A2) component (ethylenediaminetetraethanol / (A2) component) can be within the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide at the convex portion of the patterned wafer, easily achieving a high-speed polishing of silicon oxide in the non-patterned wafer, and easily suppressing the polishing rate of silicon nitride. The mass ratio B22 can be 0.01 or more, 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.75 or more, 0.8 or more, 0.9 or more, 1 or more, more than 1, 1.1 or more, or 1.2 or more. The mass ratio B22 may be 10 or less, 8 or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2 or less, 1.5 or less, 1.2 or less, 1.1 or less, 1 or less, less than 1, 0.9 or less, or 0.8 or less. From these viewpoints, the mass ratio B22 may be 0.01 to 10, 0.01 to 5, 0.01 to 2, 0.1 to 10, 0.1 to 5, 0.1 to 2, 0.5 to 10, 0.5 to 5, or 0.5 to 2.

[0116] [Other additives]

[0117] The additives of the polishing liquid involved in this embodiment may further include other components (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.

[0118] 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.

[0119] (water)

[0120] The water is not particularly limited, and may contain at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0121] (pH)

[0122] From the perspective of achieving excellent dispersion stability of abrasive particles, the pH of the polishing liquid involved in this embodiment is 5.0 or more. When the pH is 5.0 or more when the zeta potential of the abrasive particles is adjusted to be negative using an anionic dispersant, the anionic dispersant is fully dissociated and the zeta potential of the abrasive particles is easily maintained to be negative. From the perspective of easily achieving excellent dispersion stability of abrasive particles, easily obtaining a high polishing rate of silicon oxide at the convex portion of a patterned wafer, easily achieving high-speed polishing of silicon oxide in a non-patterned wafer, and easily suppressing the polishing rate of silicon nitride, the pH may be within the following range. The pH may be below 12.0, below 11.0, below 10.5, less than 10.5, below 10.0, less than 10.0, below 9.5, below 9.0, less than 9.0, below 8.8, below 8.5, below 8.2, below 8.0, less than 8.0, below 7.8, below 7.5, below 7.2, below 7.0, less than 7.0, below 6.8, below 6.7, below 6.5, below 6.2, below 6.0, less than 6.0, below 5.7, below 5.5, or below 5.4. The pH may be above 5.0, 5.2 or more, 5.4 or more, 5.5 or more, above 5.5, 5.7 or more, 6.0 or more, above 6.0, 6.2 or more, 6.5 or more, 6.7 or more, 6.8 or more, 7.0 or more, above 7.0, 7.2 or more, 7.5 or more, 7.8 or more, 8.0 or more, above 8.0 or 8.2 or more. From these viewpoints, the pH may be 5.0 to 12.0, 5.0 to 9.0, 5.0 to 7.5, 6.0 to 12.0, 6.0 to 9.0, 6.0 to 7.5, 6.5 to 12.0, 6.5 to 9.0, or 6.5 to 7.5. The pH may be measured by the method described in the Examples.

[0123] Regarding pH, since it may change depending on the type of compound used as an additive, a pH adjuster may be used to adjust the pH to the above range. There is no particular limitation on the pH adjuster, and examples thereof include acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; bases such as sodium hydroxide, ammonia (e.g., aqueous ammonia), potassium hydroxide, and calcium hydroxide. The above-mentioned additives such as component (A1), component (A2), and component (B) may be used to adjust the pH. From the viewpoint of improving productivity, the polishing liquid may be prepared without using a pH adjuster, and the polishing liquid may be directly applied to CMP.

[0124] <Preparation and use of polishing liquid>

[0125] 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 use method are different according to the type. (a) Ordinary type is a polishing liquid that can be used directly during polishing without pretreatment such as dilution. (b) Concentrated type is a polishing liquid that is concentrated in consideration of the convenience of storage or transportation compared to (a) ordinary type. (c) Multi-liquid type is a polishing liquid that is prepared in a state where the contained components are divided into a plurality of liquids during storage or transportation (for example, divided into a first liquid containing a specified component and a second liquid containing other components) and these liquids are mixed for use when used.

[0126] (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, 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.

[0127] The (b) concentrated type is diluted with water before use to obtain the desired content of the ingredients. After dilution, stirring can be continued for an arbitrary period of time until the 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.) are obtained to the same extent as those of the (a) ordinary type. In this (b) concentrated type, the volume becomes smaller according to the degree of concentration, so the storage and transportation costs can be reduced.

[0128] The concentration ratio may be 1.5 times or more, 2 times or more, 3 times or more, or 5 times or more. When the concentration ratio is 1.5 times or more, there is a tendency to easily obtain benefits in terms of storage and transportation compared to 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. When the concentration ratio is 40 times or less, there is a tendency to easily suppress the aggregation of the abrasive particles compared to a case of more than 40 times.

[0129] The (c) multi-liquid type has the advantage of being able to avoid agglomeration of abrasive grains by appropriately dividing into each liquid (first liquid, second liquid, etc.) compared to the (b) concentrated type. The components contained in each liquid may be arbitrary. The (c) multi-liquid type (polishing liquid set for CMP) is a polishing liquid set that obtains a polishing liquid by mixing a first liquid (slurry) and a second liquid (additive liquid). In the (c) multi-liquid type, the constituent components of the polishing liquid for CMP are divided into a first liquid and a second liquid for storage, the first liquid contains abrasive grains and water, and the second liquid contains at least one of the additives and water. In the first mode of the (c) multi-liquid type, the first liquid contains abrasive grains and water, and the second liquid contains at least one selected from the group consisting of the (A1) component and the (A2) component and water. In the second embodiment of the multi-liquid type (c), the first liquid contains abrasive grains, one of the components (A1) and (A2), and water, and the second liquid contains the other of the components (A1) and (A2), and water. The first liquid and the second liquid may contain other components prepared as needed. In this case, any acid or base may be prepared in the first liquid to adjust the pH so as to improve the dispersibility of the abrasive grains in the first liquid.

[0130] (c) Multi-liquid polishing liquid is useful in the case of a combination of components having a tendency to reduce the polishing properties in a relatively short period of time due to the aggregation of abrasive particles when mixed. In addition, from the viewpoint of reducing the cost of 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).

[0131] <Grinding method>

[0132] The polishing method of this embodiment includes a polishing step of polishing the polished surface using the polishing liquid of this embodiment. The polishing liquid used in the polishing step can be a polishing liquid obtained by mixing the first liquid and the second liquid in the above-mentioned polishing liquid set. That is, the polishing method of this embodiment can 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 above-mentioned polishing liquid set.

[0133] In the polishing method involved in the present embodiment, a polishing liquid in which the content of each component, pH, etc. are adjusted can be used 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 an ILD film, 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 effectively improving the polishing speed of silicon oxide in a patternless wafer and the effect of improving the in-plane uniformity can be 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 the abrasive particles, and to achieve a sufficiently high polishing speed while reducing the generation of polishing scratches.

[0134] 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 through 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 through the grinding component.

[0135] The grinding method involved in this embodiment can be a method in which 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.

[0136] 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 the device, there can be cited individual 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 mode 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.

[0137] 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 substrates that are difficult to achieve a high polishing rate by using the conventional polishing liquid method.

[0138] The grinding method involved in the present embodiment is suitable for flattening a surface to be ground having 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 the surface of a portion including a concave portion or a convex portion in a T-shape or a lattice shape 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 memory unit at a high speed. These methods using conventional CMP grinding liquids are difficult to achieve high grinding speeds, which means that one method of the grinding liquid involved in the present embodiment can achieve high grinding speeds without relying largely on the concave and convex shape of the surface to be ground.

[0139] 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 an inorganic insulating film such as silicon oxide, glass, silicon nitride, or a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc. on a wiring board having prescribed wiring.

[0140] 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 1 is a schematic cross-sectional view showing a process of polishing the ILD film, and shows a process of forming the ILD film between wirings. 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.

[0141] 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 so as 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 so as to penetrate the ILD film 10.

[0142] In the process of forming the ILD film structure, in order to eliminate the step difference D, the unnecessary part protruding locally on the surface of the silicon oxide film 30 is preferentially removed by CMP. When grinding the silicon oxide film 30, the substrate 100 is arranged on the grinding component in such a way 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 platform, 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.

[0143] As a grinding device for grinding, for example, a device having a support for holding a substrate, a grinding platform for attaching a grinding pad, and a mechanism for supplying abrasive liquid to the grinding pad can be used. As a grinding device, a grinding device (model: EPO-111, EPO-222, F-REX200 and F-REX300) manufactured by EBARA CORPORATION and a grinding device (product name: Mirra3400 and Reflexion) manufactured by Applied Materials, Inc. 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, the grinding pad can be grooved to store the grinding liquid.

[0144] There is no particular restriction on the grinding conditions. From the perspective of preventing the substrate from being thrown out, the rotation speed of the grinding platform can be 200 min. -1 Below. From the viewpoint of easily suppressing the grinding scratches of the ground surface, the pressure (processing load) applied to the substrate can be below 100kPa. During grinding, the grinding pad can be continuously supplied with grinding liquid by a pump or the like. The supply amount is not limited, and the surface of the grinding pad can always be covered with grinding liquid. After grinding, the substrate can be fully cleaned in running water, and then dried after shaking off the water droplets attached to the substrate using a rotary dryer or the like.

[0145] By polishing in the above manner to eliminate the surface irregularities, 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.

[0146] 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-state 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.

[0147] <Manufacturing method, etc.>

[0148] The manufacturing method of the part involved in the present embodiment includes a part manufacturing process of obtaining a 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 (such as a semiconductor part such as a semiconductor package), a wafer (such as a semiconductor wafer), or a chip (such as 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 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 (such as a semiconductor package) is obtained 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.

[0149] As one mode of the part manufacturing process, the part manufacturing method involved in the present embodiment may include a singulation process of singulating the substrate (the part to be polished) 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 part manufacturing method involved in the present embodiment, the electronic part manufacturing method involved in the present embodiment may include a process of singulating the substrate polished by the polishing method involved in the present embodiment to obtain an electronic part (for example, a semiconductor part). As one mode of the part manufacturing method involved in the present embodiment, the semiconductor part manufacturing method involved in the present embodiment may include a process of singulating the substrate polished by the polishing method involved in the present embodiment to obtain a semiconductor part (for example, a semiconductor package).

[0150] As one mode of the part manufacturing process, the part manufacturing method involved in the present embodiment may include a connection process of connecting (for example, electrically connecting) a substrate (a polished part) polished by the polishing method involved in the present embodiment to another connected body. The connected body connected to the substrate polished by the polishing method involved in the present embodiment is not particularly limited, and may be a substrate polished by the polishing method involved in the present embodiment, or may be a connected body different from the substrate polished by the polishing 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.

[0151] 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 to 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 to 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. Through the connection process, a connected body having a substrate and a connected body can be obtained. In the connection process, when the connecting surface of the substrate has a metal part, the connected body can be brought into contact with the metal part. 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.

[0152] A 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.

[0153] Example

[0154] Hereinafter, the present invention will be described in further detail based on examples, but the present invention is not limited to these examples.

[0155] <Production of cerium oxide powder>

[0156] 40 kg of cerium carbonate hydrate was divided into 10 aluminum containers and calcined in air at 830°C for 2 hours to obtain a total of 20 kg of yellow-white powder. The powder was homologously identified by X-ray diffraction, and it was confirmed that the powder contained polycrystalline cerium oxide. The particle size of the powder obtained by calcination was observed by SEM, and the result was in the range of 20 to 100 μm. Then, 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.

[0157] <Preparation of slurry>

[0158] 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, 0.375 kg of an aqueous solution of ammonium polyacrylate (concentration 40 mass %, molecular weight: about 10,000) or 0.15 kg of ammonium dihydrogen phosphate (ADP) was added as a dispersant and stirred for 10 minutes to obtain a cerium oxide mixed solution. 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.

[0159] 500 g ± 5 g of the cerium oxide mixed solution sent through 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. Slurry was obtained by mixing the supernatant portions collected from the four containers. Regarding the slurry, about 6.0 mass % of cerium oxide particles were contained based on the total mass of the slurry.

[0160] The slurry was diluted with pure water in such a manner that the content of the abrasive particles having a scattering intensity suitable for the measurement range was obtained, thereby obtaining a sample for particle size measurement. For this sample, the average particle size of the abrasive particles was measured using a laser diffraction-scattering particle size distribution measuring device (manufactured by Microtrac BEL Corp., product name: Microtrac MT3300EXII), and the result showed that the average particle size of the abrasive particles was 140 nm.

[0161] <Preparation of CMP polishing slurry>

[0162] By mixing the above slurry, various additives and deionized water according to the following steps, polishing liquids having the compositions shown in the following tables (balance: deionized water) were obtained (wherein, in Comparative Examples 1, 2 and 6, no additives other than the dispersant mixed when preparing the above slurry were used). In the table, "THEED" represents 2,2',2",2"'-ethylenediaminetetraethanol. In each polishing liquid, 1 part by mass of ammonium polyacrylate or 1 part by mass of ammonium dihydrogen phosphate (ADP) may be contained as the dispersant mixed when preparing the above slurry, relative to 100 parts by mass of the abrasive particles.

[0163] 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 %, and contained 2.5 times the amount of abrasive grains and additives relative to the final polishing liquid content of 2.00 mass %.

[0164] Furthermore, the polishing liquids of Examples 1 to 4, 13 to 14, 21 to 26 and Comparative Examples 1 and 6 were obtained by diluting the polishing liquid stock solution with deionized water to 10 times. Furthermore, the polishing liquids of Examples 5 to 12, 15 to 20 and Comparative Examples 2 to 5 were obtained by diluting the polishing liquid stock solution with deionized water to 2.5 times. 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 above slurry was equal to the average particle size of the abrasive particles in the above slurry.

[0165] <Zeta potential measurement>

[0166] 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 zeta potential indicated was obtained and used as the zeta potential. In each of the Examples and Comparative Examples, the zeta potential of the abrasive grains was negative as shown in each table.

[0167] <pH measurement>

[0168] The pH of the polishing liquid was measured under the following conditions. The results are shown in the tables.

[0169] Measurement temperature: 25℃

[0170] Measuring device: HORIBA, Ltd. Product name: Model (D-71)

[0171] Measuring 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 measuring device after it had stabilized for more than 2 minutes.

[0172] <Evaluation of dispersion stability of abrasive particles>

[0173] The polishing liquid just prepared was allowed to stand for 1 week (168 hours), and the average particle size of the abrasive grains 3 hours after preparation and 1 week after preparation was measured by the same method as the average particle size of the abrasive grains in the slurry. As the rate of change of the average particle size of the abrasive grains 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 grains in the slurry) / average particle size of the abrasive grains in the slurry] × 100" was calculated. The case where the rate of change of the average particle size of the abrasive grains after 1 week (and the rate of change of the average particle size of the abrasive grains 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 grains after 1 week exceeded 4% but the rate of change of the average particle size of the abrasive grains 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 grains after 3 hours exceeded 4% was judged as "C". The results are shown in the tables.

[0174] <Evaluation of polishing characteristics>

[0175] (Preparation of evaluation wafers)

[0176] As a bare wafer (BKW), a wafer having a silicon oxide film (SiO 2 , initial film thickness: 1000 nm) and a φ200 mm unpatterned wafer having a silicon nitride film (SiN, initial film thickness: 200 nm) on the surface.

[0177] 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 grain units, and each grain unit has a plurality of 4 mm × 4 mm unit areas. The pattern wafer has an area of ​​parallel line patterns as a 4 mm × 4 mm unit area, in which the pitch of the line pattern is 100 μm wide, and the Line / Space (L / S) is 10 μm / 90 μm (density of convex parts: 10%) to 90 μm / 10 μm (density of convex parts: 90%) on a 10 μm scale.

[0178] (Grinding process)

[0179] The evaluation wafer was ground using a grinding device (Applied Materials, Inc., product name: Mirra3400). The evaluation wafer was mounted on a bracket having an adsorption pad for substrate mounting. A polishing pad made of porous urethane resin (K-groove, DuPont (Dow) Company, model: IC-1010) was attached to a grinding platform with a diameter of 500 mm.

[0180] The polished surface of the evaluation wafer was placed downward and the holder was placed on the polishing pad. The inner tube pressure, the fixing ring pressure and the membrane pressure were set to 14 kPa, 21 kPa and 14 kPa respectively.

[0181] Then, the polishing liquid (except for Comparative Examples 3 to 5) was dripped onto the polishing pad attached to the polishing platen at a flow rate of 200 mL / min, and 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 non-patterned wafer was polished for 30 seconds. In the patterned wafer, the time during which the silicon nitride film of the base of the silicon oxide film in the convex portion of the L / S=20μm / 80μm ​​region was not exposed was set as the polishing time in the range of 20 to 60 seconds according to the polishing speed evaluated in the non-patterned wafer, 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.

[0182] (Evaluation of polishing speed)

[0183] Using an optical interference film thickness measuring device (manufactured by Nanometrics, Inc., product name: AFT-5100), the film thickness change of the polished film before and after polishing was measured as follows, and the polishing rate was obtained. In addition, the polishing rate ratio (PTW / BKW) of silicon oxide at the convex portion of the patterned wafer to silicon oxide in the non-patterned wafer was calculated. The results are shown in each table.

[0184] In the case of a non-patterned wafer, the film thickness variation was measured at a total of 41 measurement points (20 on both sides of the center point) at intervals of 5 mm from the center point in the radial direction of the wafer (the next measurement point of the measurement point 95 mm from the center was set to a position 97 mm from the center). The film thickness variation in a polishing time of 30 seconds was measured at these 41 points, and the average value was obtained and used as the polishing rate of the non-patterned wafer.

[0185] 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 grain 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.

[0186] [Table 1]

[0187]

[0188] [Table 2]

[0189]

[0190] [Table 3]

[0191]

[0192] [Table 4]

[0193]

[0194] Explanation of symbols

[0195] 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 particles, an additive and water. The abrasive grains include cerium-based particles, The zeta potential of the abrasive particles is negative. The additive comprises (A1) a 4-pyrone compound represented by the following general formula (1), The pH of the CMP polishing liquid is 5.0 or more. Where, X 11 , X 12 and X 13 Each independently represents a hydrogen atom or a monovalent substituent.

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

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

4. The CMP polishing liquid according to claim 1, wherein The additive further includes (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

5. The CMP polishing liquid according to claim 4, wherein The component (B) includes ethylenediaminetetraethanol.

6. The CMP polishing liquid according to claim 1, wherein The pH of the CMP polishing liquid is 8.0 or less.

7. A CMP polishing liquid comprising abrasive particles, an additive and water. The abrasive grains include cerium-based particles, The zeta potential of the abrasive particles is negative. The additive comprises (A2) a 2-pyridinecarboxylic acid compound, The pH of the CMP polishing liquid is 5.0 or higher.

8. The CMP polishing liquid according to claim 7, wherein: The component (A2) contains 2-picolinic acid.

9. The CMP polishing liquid according to claim 7, wherein: The component (A2) contains hydroxy 2-picolinic acid.

10. The CMP polishing liquid according to claim 7, wherein: The component (A2) contains amino 2-picolinic acid.

11. The CMP polishing liquid according to claim 7, wherein: The content of the component (A2) is 0.001 to 5% by mass.

12. The CMP polishing liquid according to claim 7, wherein: The additive further includes (B) a compound having two or more nitrogen atoms to which a hydroxyalkyl group is bonded.

13. The CMP polishing liquid according to claim 12, wherein: The component (B) includes ethylenediaminetetraethanol.

14. The CMP polishing liquid according to claim 7, wherein The pH of the CMP polishing liquid is 8.0 or less.

15. A CMP polishing liquid kit, wherein: The constituent components of the CMP polishing liquid according to any one of claims 1 to 14 are stored separately as a first liquid and a second liquid, wherein the first liquid contains the abrasive grains and water, and the second liquid contains at least one of the additives 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. 18 . A polishing method comprising the step of polishing a surface to be polished using a CMP polishing liquid obtained by mixing the first liquid and the second liquid in the CMP polishing liquid set according to claim 15 .

19. The grinding method according to claim 18, wherein: The polished surface includes silicon oxide.

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