Cmp slurry and polishing method

Abstract

An aspect of the present application provides a CMP polishing liquid for polishing polysilicon, the CMP polishing liquid containing abrasive grains and a cationic polymer, the cationic polymer including at least one selected from the group consisting of a polymer A having a main chain including a nitrogen atom and a carbon atom and a hydroxyl group bonded to the carbon atom and an allylamine polymer B. Another aspect of the present application provides a polishing method including a step of polishing a polishing target material using the CMP polishing liquid.

Description

Technical Field

[0001] This invention relates to a CMP polishing slurry and polishing method, etc. Background Technology

[0002] In the field of semiconductor manufacturing, with the increasing performance of memory devices (such as very large-scale integrated circuit devices), the ability to achieve both high integration and high speed through miniaturization techniques on extended lines of conventional technologies has reached its limit. Therefore, a technology has been developed that enables the miniaturization of semiconductor components while also achieving high integration in the vertical direction (i.e., a technology that multilayers wiring, components, etc.).

[0003] In the manufacturing process of multilayered devices such as wiring and components, CMP (Chemical Mechanical Polishing) technology is one of the most important technologies. CMP technology is a technique for planarizing the surface of a substrate after a thin film is formed on it using chemical vapor deposition (CVD) or similar methods. If the surface of the planarized substrate is uneven, the following problems will occur: it will be impossible to focus during the exposure process, or it will be impossible to form a sufficiently fine wiring structure. CMP technology is also applied in the following processes in device manufacturing: the process of forming component separation regions by polishing plasma oxide films (BPSG, HDP-SiO2, p-TEOS, etc.); the process of forming interlayer insulating films; and the process of planarizing plugs (e.g., Al·Cu plugs) after embedding silicon oxide films (films containing silicon oxide) into metal wiring.

[0004] Regarding CMP, it is typically performed using a device capable of supplying CMP polishing slurry to a polishing pad. While supplying CMP polishing slurry between the surface of the substrate and the polishing pad, the substrate is pressed onto the polishing pad, thereby polishing the surface of the substrate. In CMP technology, high-performance CMP polishing slurry is one of the key technologies, and various CMP polishing slurries have been developed to date (for example, see Patent Document 1 below).

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-175731 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] In the process of forming component separation regions on a substrate, a polishing material is formed to fill the irregularities pre-formed on the surface of the substrate. Subsequently, the component separation regions are formed by planarizing the surface of the polishing material using CMP (Continuous Mechanical Polishing). When the polishing material is formed on a substrate with irregularities on its surface used to obtain component separation regions, irregularities corresponding to those on the substrate are also generated on the surface of the polishing material. In polishing a surface with irregularities, the protrusions are removed first, while the recesses are gradually removed, thereby achieving planarization.

[0010] To increase semiconductor production throughput, it is preferable to remove unwanted portions of the polished material formed on the substrate at the highest possible speed. For example, in the fabrication of 3D-NAND as memory layers are stacked, it is required to remove polysilicon, such as gates, from the substrate at high polishing speeds. Therefore, CMP polishing slurries are required to polish polysilicon at high speeds.

[0011] One objective of the present invention is to provide a CMP polishing slurry capable of achieving high polishing speeds in polycrystalline silicon. Furthermore, another objective of the present invention is to provide a polishing method using such a CMP polishing slurry.

[0012] means for solving technical problems

[0013] One aspect of the present invention provides a CMP polishing slurry for polishing polycrystalline silicon, the CMP polishing slurry containing abrasive particles and a cationic polymer, the cationic polymer comprising at least one polymer selected from the group consisting of a polymer A having a main chain containing nitrogen atoms and carbon atoms and hydroxyl groups bonded to the carbon atoms and an allylamine polymer B.

[0014] Another aspect of the present invention provides a grinding method comprising the step of grinding a material to be ground using the above-described CMP grinding fluid.

[0015] Based on this CMP polishing slurry and polishing method, high polishing speeds for polycrystalline silicon can be achieved.

[0016] Invention Effects

[0017] According to one aspect of the present invention, a CMP polishing slurry capable of achieving high polishing speeds in polycrystalline silicon can be provided. According to another aspect of the present invention, a polishing method using such a CMP polishing slurry can be provided. Detailed Implementation

[0018] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to the following embodiments and can be implemented in various ways within its scope.

[0019] In this specification, the numerical range indicated by "~" represents the range included by the values ​​recorded before and after "~" as the minimum and maximum values, respectively. Within the numerical ranges described in stages in this specification, the upper or lower limit of a certain stage's numerical range can be arbitrarily combined with the upper or lower limits of the numerical ranges of other stages. Within the numerical ranges described in this specification, the upper or lower limit of the numerical range can be replaced with the values ​​shown in the examples. "A or B" can include either A or B, or both. Regarding the materials exemplified in this specification, unless otherwise specified, one type can be used alone or two or more types can be used in combination. In this specification, the amount of each component used in the composition, when multiple substances equivalent to each component are present in the composition, refers to the total amount of the multiple substances present in the composition unless otherwise specified. In this specification, the term "membrane" includes not only the shape and structure formed over the entire surface when viewed in a top view, but also the shape and structure formed locally. In this specification, the term "process" includes not only independent processes, but also processes that achieve their desired effect even when they cannot be clearly distinguished from other processes.

[0020] <CMP polishing slurry>

[0021] The CMP polishing slurry (CMP polishing slurry) involved in this embodiment is a CMP polishing slurry used for polishing polycrystalline silicon. The CMP polishing slurry involved in this embodiment contains abrasive grains (polishing particles) and a cationic polymer. The cationic polymer includes at least one selected from the group consisting of polymer A having a main chain containing nitrogen atoms (N atoms) and carbon atoms (C atoms) and hydroxyl groups bonded to the carbon atoms, and allylamine polymer B (hereinafter referred to as "polymer B") (hereinafter collectively referred to as "specific cationic polymer"). The specific cationic polymer of the CMP polishing slurry involved in this embodiment may be in a manner containing polymer A and polymer B, in a manner containing polymer A and not containing polymer B, or in a manner containing polymer B and not containing polymer A.

[0022] According to the CMP polishing slurry of this embodiment, a high polishing speed for polycrystalline silicon can be obtained. According to the CMP polishing slurry of this embodiment, the evaluation method described in the examples can achieve… The grinding speed of polycrystalline silicon is above / min. While the main reason for achieving such high grinding speeds in polycrystalline silicon is not necessarily clear, it is speculated as follows. However, the main reason is not limited to the following: Specifically, certain cationic polymers adsorb onto the surface of polycrystalline silicon, creating polarity in the silicon-silicon bonds. Therefore, it is inferred that the bonds are easily broken due to brittleness, thus enabling the high grinding speed of polycrystalline silicon.

[0023] According to the CMP polishing slurry of this embodiment, it is possible to obtain a high polishing speed for polycrystalline silicon while suppressing the polishing speed for silicon oxide. According to the CMP polishing slurry of this embodiment, in the evaluation method described in the examples, the polishing speed ratio of polycrystalline silicon to silicon oxide (polishing speed of polycrystalline silicon / polishing speed of silicon oxide) can be 1 or more (for example, 3 or more).

[0024] According to the CMP polishing slurry of this embodiment, the polishing speed ratio of silicon nitride to silicon oxide (polishing speed of silicon nitride / polishing speed of silicon oxide) can also be improved. According to the CMP polishing slurry of this embodiment, in the evaluation method described in the examples, the polishing speed ratio of silicon nitride to silicon oxide can be 0.2 or more (for example, 0.5 or more).

[0025] Regarding the CMP polishing slurry involved in this embodiment, as long as a high polishing speed can be obtained when polishing polycrystalline silicon, it can be used for polishing materials different from polycrystalline silicon. The CMP polishing slurry involved in this embodiment can be used for polishing silicon nitride, or for polishing polycrystalline silicon and silicon nitride. The CMP polishing slurry involved in this embodiment can be used for polishing silicon oxide, or for polishing polycrystalline silicon and silicon oxide, silicon nitride and silicon oxide, or polycrystalline silicon, silicon nitride and silicon oxide. The CMP polishing slurry involved in this embodiment can be used for polishing materials with a substrate having at least one material selected from the group consisting of polycrystalline silicon, silicon nitride and silicon oxide on its surface.

[0026] (Abrasive grains)

[0027] Abrasive particles can contain, for example, cerium-based compounds, alumina, silicon dioxide, titanium dioxide, zirconium oxide, magnesium oxide, mullite, silicon nitride, α-silicon nitride, aluminum nitride, titanium nitride, silicon carbide, boron carbide, etc. The constituent components of the abrasive particles can be used alone or in combination of two or more. From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and easily suppressing grinding speeds of silicon oxide, the abrasive particles can contain at least one component selected from the group consisting of cerium-based compounds and silicon dioxide.

[0028] However, in the fabrication of 3D-NAND, it is sometimes required to remove polysilicon and silicon nitride at high polishing speeds. Previously, because it was difficult to simultaneously polish polysilicon and silicon nitride at high polishing speeds using a single CMP polishing slurry, different types of CMP polishing slurries were used, and polishing was performed in two separate stages: polishing polysilicon and polishing silicon nitride. However, from the viewpoint of improving productivity and simplifying equipment, it is desirable to complete the polishing in a single stage. In contrast, the CMP polishing slurry according to this embodiment, by containing cerium-based compounds in the abrasive grains, can achieve high polishing speeds for both polysilicon and silicon nitride, and can achieve high polishing speeds for silicon nitride while suppressing the polishing speed of silicon oxide.

[0029] Examples of cerium-based compounds include cerium oxide (cerium oxide), cerium hydroxide, cerium ammonium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. From the perspectives of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, easily suppressing the polishing speed of silicon oxide, and easily obtaining a polished surface with minimal polishing damage, cerium-based compounds can include cerium oxide.

[0030] When using cerium oxide, the abrasive grains can contain polycrystalline cerium oxide with grain boundaries (e.g., polycrystalline cerium oxide with multiple microcrystals surrounded by grain boundaries). Unlike simple aggregates formed by the aggregation of single crystal particles, such polycrystalline cerium oxide particles become finer due to stress during grinding, and active surfaces (surfaces not exposed to the outside before finening) appear one after another. Therefore, it is believed that a high grinding speed can be maintained for the material being ground.

[0031] Examples of methods for manufacturing abrasive grains containing cerium oxide include liquid-phase synthesis, sintering, and oxidation using hydrogen peroxide. When obtaining abrasive grains containing polycrystalline cerium oxide with grain boundaries, a sintering method using a cerium source such as cerium carbonate can be used. The sintering temperature can be, for example, 350–900°C. If the manufactured cerium oxide particles agglomerate, they can be mechanically pulverized.

[0032] When abrasive grains contain cerium-based compounds (e.g., cerium oxide), from the viewpoints of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and easily suppressing the grinding speed of silicon oxide, the content of cerium-based compounds in the abrasive grains (the entire abrasive grains contained in the CMP polishing slurry) can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, or substantially 100% by mass (in the manner in which the abrasive grains are substantially formed of cerium-based compounds).

[0033] When abrasive grains contain silicon oxide, from the viewpoints of easily obtaining high grinding speeds of polycrystalline silicon and easily suppressing grinding speeds of silicon oxide, the silicon oxide content in the abrasive grains can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, or 99% by mass or more, or substantially 100% by mass (in the manner in which the abrasive grains are substantially formed of silicon oxide), based on the entire abrasive grain (the entire abrasive grain contained in the CMP polishing slurry).

[0034] Based on the entire abrasive grain (the entire abrasive grain contained in the CMP polishing slurry), the content of hydroxides (e.g., the content of cerium hydroxide) in the abrasive grain can be less than 0.01% by mass, less than 0.001% by mass, or less than 0.0001% by mass. The abrasive grain may not contain hydroxides (e.g., cerium hydroxide) (the content of hydroxides (e.g., the content of cerium hydroxide) can be substantially 0% by mass).

[0035] The average particle size of abrasive grains in CMP polishing slurries can be within the following ranges. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, the average particle size of the abrasive grains can be 50 nm or more, 70 nm or more, exceeding 70 nm, 75 nm or more, 80 nm or more, 85 nm or more, or 90 nm or more. From the viewpoint of easily suppressing polishing damage, the average particle size of the abrasive grains can be 500 nm or less, 300 nm or less, 280 nm or less, 250 nm or less, 200 nm or less, 180 nm or less, 160 nm or less, 150 nm or less, 120 nm or less, 100 nm or less, or 90 nm or less. From these viewpoints, the average particle size of the abrasive grains can be 50–500 nm.

[0036] To control the average particle size of abrasive particles, conventionally known methods can be used. Taking cerium oxide particles as an example, methods for controlling the average particle size of abrasive particles include controlling the firing temperature, firing time, and grinding conditions, as well as applications such as filtration and classification.

[0037] The average particle size of the abrasive grains can be obtained using the arithmetic mean diameter measured by a laser diffraction / scattering particle size analyzer. Regarding the average particle size of the abrasive grains, for example, it can be measured using the method described in the examples, such as the LA-920 (trade name) manufactured by HORIBA, Ltd.

[0038] The content of abrasive particles relative to 100 parts by weight of CMP polishing slurry can be within the following ranges. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, the content of abrasive particles can be 0.01 parts by weight or more, 0.05 parts by weight or more, 0.08 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, 0.8 parts by weight or more, 1.0 parts by weight or more, 1.5 parts by weight or more, or 2.0 parts by weight or more. From the viewpoint of easily suppressing abrasive particle aggregation and easily suppressing the polishing speed of silicon oxide, the content of abrasive particles can be 10 parts by weight or less, 5.0 parts by weight or less, 3.0 parts by weight or less, 2.0 parts by weight or less, less than 2.0 parts by weight, 1.5 parts by weight or less, 1.0 parts by weight or less, 0.8 parts by weight or less, or 0.5 parts by weight or less. From these perspectives, the content of abrasive particles can be 0.01–10 parts by mass, 0.1–10 parts by mass, or 0.1–2 parts by mass.

[0039] (Catonic polymer)

[0040] The CMP polishing slurry of this embodiment contains a specific cationic polymer, which includes at least one polymer selected from polymer A and polymer B (allylamine polymer, excluding compounds corresponding to polymer A) having a main chain containing nitrogen and carbon atoms and hydroxyl groups bonded to the carbon atoms. The CMP polishing slurry of this embodiment may contain cationic polymers other than the specific cationic polymer, or it may not contain cationic polymers other than the specific cationic polymer. A "cationic polymer" is defined as a polymer having a cationic group or capable of ionizing into a cationic group. Examples of cationic groups include amino and imino groups. One cationic polymer (e.g., the specific cationic polymer) may be used alone or in combination of two or more.

[0041] Certain cationic polymers can be water-soluble. By using compounds with high water solubility, desired amounts of a particular cationic polymer can be readily dissolved in CMP polishing slurries. The solubility of a particular cationic polymer in 100g of water at room temperature (25°C) can be greater than 0.005g or 0.02g. There is no particular upper limit to the solubility.

[0042] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing grinding speeds for silicon oxide, a specific cationic polymer may comprise polymer P as polymer A or polymer B, polymer P having a main chain containing carbon atoms and side chains bonded to the main chain, and at least one of the main chain and side chains containing nitrogen atoms selected from the group consisting of the main chain and side chains. "Main chain" refers to the longest molecular chain. "Side chain" refers to a molecular chain branching from the main chain (e.g., a molecular chain containing carbon atoms). The side chain may be bonded to multiple atoms constituting the main chain (e.g., two atoms).

[0043] From the viewpoint that the grinding speed of silica can be easily suppressed by the adsorption of polymer P onto silica, the maximum molecular weight of the side chain in polymer P can be 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, 30 or less, or 20 or less. The maximum molecular weight of the side chain in polymer P can be 15 or more.

[0044] A specific cationic polymer can contain polymer A. In polymer A, hydroxyl groups are directly bonded to carbon atoms in the main chain. From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, polymer A can have structural units with a main chain containing nitrogen atoms and carbon atoms, or it can have multiple (e.g., two) structural units with a main chain containing nitrogen atoms and carbon atoms.

[0045] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing grinding speeds for silicon oxide, polymer A can satisfy at least one of the following characteristics, and can also have a structural unit that satisfies at least one of the following characteristics (a structural unit having a main chain containing nitrogen atoms and carbon atoms).

[0046] The main chain containing nitrogen and carbon atoms may include a nitrogen atom and an alkylene chain bonded to that nitrogen atom. A hydroxyl group may be bonded to a carbon atom in the alkylene chain. The alkylene chain has 1 or more carbon atoms, and can have 2 or more, or 3 or more. The alkylene chain can have 6 or fewer, 5 or fewer, or 4 or fewer carbon atoms. The alkylene chain can have 1 to 6 carbon atoms.

[0047] Polymer A may contain nitrogen atoms constituting a quaternary ammonium salt. The quaternary ammonium salt may contain nitrogen atoms bonded to at least one alkyl group selected from the group consisting of alkyl and aryl groups, or nitrogen atoms bonded to a methyl group. The quaternary ammonium salt may contain nitrogen atoms bonded to two alkyl groups, or nitrogen atoms bonded to two methyl groups. The quaternary ammonium salt may contain ammonium cations and chloride ions.

[0048] Polymer A may contain nitrogen atoms that form acid addition salts or nitrogen atoms that form hydrochloride salts.

[0049] In polymer A, the carbon atoms bonded to the nitrogen atom and the hydroxyl group may or may not be adjacent. From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, polymer A may have a hydrocarbon group between the carbon atoms bonded to the nitrogen atom and the hydroxyl group, or it may have a hydrocarbon group with one carbon atom between the carbon atoms bonded to the nitrogen atom and the hydroxyl group (e.g., methylene). From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, as a structural unit having a main chain containing nitrogen atoms and carbon atoms, polymer A may have a structural unit having a hydrocarbon group between the carbon atoms bonded to the nitrogen atom and the hydroxyl group, or it may have a structural unit having a hydrocarbon group with one carbon atom between the carbon atoms bonded to the nitrogen atom and the hydroxyl group (e.g., methylene) as a structural unit having a main chain containing nitrogen atoms and carbon atoms.

[0050] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and easily suppressing the grinding speed of silicon oxide, polymer A may contain a reactant (e.g., a condensate) containing at least dimethylamine and epichlorohydrin, or a reactant (e.g., a condensate) containing at least dimethylamine, ammonia, and epichlorohydrin. The reactant may contain compounds other than dimethylamine, ammonia, and epichlorohydrin. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and easily suppressing the grinding speed of silicon oxide, polymer A may contain a compound having a structure represented by the following formula. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and easily suppressing the grinding speed of silicon oxide, polymer A may contain at least one selected from the group consisting of dimethylamine / epoxychlorohydrin condensate (condensate) and dimethylamine / ammonia / epoxychlorohydrin condensate (condensate). The CMP polishing slurry involved in this embodiment may be free of reactants (e.g., condensates) containing raw materials including dimethylamine, epichlorohydrin, and ethylenediamine as polymer A.

[0051]

[0052] [In the formula, a represents an integer greater than or equal to 1, and b represents an integer greater than or equal to 0 (e.g., greater than or equal to 1).]

[0053] From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, the molecular weight (e.g., weight-average molecular weight) of polymer A can be within the following range: 5000 or more, 7000 or more, 8000 or more, 10000 or more, 15000 or more, more than 15000, 30000 or more, 50000 or more, 60000 or more, 80000 or more, 100000 or more, 200000 or more, 300000 or more, 400000 or more, 450000 or more, 500000 or more, 600000 or more, 800000 or more, 1,000000 or more, or 1,200000 or more. The molecular weight of polymer A can be less than 2,000,000, less than 1,500,000, less than 1,300,000, less than 1,200,000, less than 1,000,000, less than 800,000, less than 600,000, less than 500,000, less than 450,000, less than 400,000, less than 300,000, less than 200,000, less than 100,000, less than 60,000, less than 50,000, less than 30,000, less than 15,000, less than 15,000, less than 10,000, or less than 8,000. From these perspectives, the molecular weight of polymer A can be 5,000–2,000,000, 5,000–1,500,000, 10,000–2,000,000, 10,000–1,000,000, 50,000–500,000, or 100,000–500,000. The molecular weight (e.g., weight-average molecular weight) of polymer A can be determined using the methods described in the examples.

[0054] When a specific cationic polymer contains polymer A, from the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, the content of polymer A in the cationic polymer or the specific cationic polymer can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, or substantially 100% by mass (in the manner in which the cationic polymer or the specific cationic polymer is substantially formed from polymer A) based on the whole cationic polymer (the whole cationic polymer contained in the CMP polishing slurry) or the whole specific cationic polymer (the whole specific cationic polymer contained in the CMP polishing slurry).

[0055] The content of polymer A relative to 100 parts by weight of CMP polishing slurry can be within the following range. From the viewpoint of easily obtaining high polishing speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the polishing speed of silicon oxide, the content of polymer A can be 0.00001 parts by weight or more, 0.00005 parts by weight or more, 0.0001 parts by weight or more, 0.0002 parts by weight or more, 0.0003 parts by weight or more, 0.0005 parts by weight or more, 0.0008 parts by weight or more, 0.001 parts by weight or more, 0.002 parts by weight or more, 0.0025 parts by weight or more, 0.003 parts by weight or more, 0.004 parts by weight or more, 0.005 parts by weight or more, 0.008 parts by weight or more, 0.012 parts by weight or more, or 0.015 parts by weight or more. From the viewpoint of easily suppressing the grinding speed of silicon oxide, the content of polymer A can be 0.02 parts by mass or more, 0.025 parts by mass or more, 0.03 parts by mass or more, 0.04 parts by mass or more, 0.05 parts by mass or more, 0.08 parts by mass or more, or 0.1 parts by mass or more. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, the content of polymer A can be 10 parts by mass or less, 5 parts by mass or less, 2.5 parts by mass or less, less than 2.5 parts by mass, 2 parts by mass or less, 1 part by mass or less, 0.5 parts by mass or less, 0.1 parts by mass or less, 0.08 parts by mass or less, or 0.05 parts by mass or less. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, the content of polymer A can be 0.04 parts by mass or less, 0.03 parts by mass or less, 0.025 parts by mass or less, 0.02 parts by mass or less, or 0.015 parts by mass or less. From the viewpoint of easily obtaining high grinding speeds for silicon nitride, the content of polymer A can be 0.012 parts by mass or less, 0.01 parts by mass or less, 0.008 parts by mass or less, or 0.005 parts by mass or less. The content of polymer A can be 0.004 parts by mass or less, 0.003 parts by mass or less, or 0.0025 parts by mass or less. From these viewpoints, the content of polymer A can be 0.00001 to 10 parts by mass, 0.0001 to 1 part by mass, 0.0025 to 0.1 parts by mass, or 0.001 to 0.1 parts by mass.

[0056] The ratio A of the abrasive content to the polymer A content can be within the following ranges. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, the ratio A can be 0.1 or more, 0.5 or more, 1 or more, more than 1, 2 or more, 3 or more, 5 or more, 8 or more, or 10 or more. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, the ratio A can be 15 or more, 20 or more, 25 or more, 30 or more, or 33 or more. From the viewpoint of easily obtaining high grinding speeds for silicon nitride, the ratio A can be 40 or more, 50 or more, 60 or more, 62.5 or more, 67 or more, 80 or more, or 100 or more. The ratio A can be 120 or more, 150 or more, 167 or more, 200 or more, 300 or more, 400 or more, or 500 or more. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, the ratio A can be 1000 or less, 800 or less, 500 or less, 400 or less, 300 or less, 200 or less, 167 or less, 150 or less, 120 or less, 100 or less, 80 or less, 67 or less, 62.5 or less, 60 or less, 50 or less, 40 or less, or 33 or less. From the viewpoint of easily suppressing polishing speeds for silicon oxide, the ratio A can be 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 8 or less, or 5 or less. From these viewpoints, the ratio A can be 0.1 to 1000, 1 to 500, or 5 to 100.

[0057] Certain cationic polymers can include polymer B. Polymer B is an allylamine polymer, and is a polymer having an allylamine compound (a compound having allyl and amino groups) as a monomer unit (a polymer having structural units derived from an allylamine compound). From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, polymer B can include a polymer having a diallyl dialkylammonium salt as a monomer unit.

[0058] From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, polymer B may have at least one structural unit selected from the group consisting of structural units represented by general formula (I), general formula (II), general formula (III), general formula (IV), and general formula (V). As structural units included in polymer B, the structural units represented by general formulas (I) to (V) may be a single type or two or more types.

[0059]

[0060] [In the formula, R]11 and R 12 Each can independently represent a hydrogen atom, alkyl group, or aralkyl group; amino groups can form acid addition salts.

[0061]

[0062] [In the formula, R] 2 This indicates a hydrogen atom, alkyl group, or aralkyl group; nitrogen-containing rings can form acid addition salts.

[0063]

[0064] [In the formula, R] 3 This indicates a hydrogen atom, alkyl group, or aralkyl group; nitrogen-containing rings can form acid addition salts.

[0065]

[0066] [In the formula, R] 41 and R 42 Each independently represents a hydrogen atom, alkyl group, or aralkyl group, D - This represents a monovalent anion.

[0067]

[0068] [In the formula, R] 51 and R 52 Each independently represents a hydrogen atom, alkyl group, or aralkyl group, D - This represents a monovalent anion.

[0069] R in general formulas (I), (II) and (III) 11 R 12 R 2 and R 3 The alkyl group can be any of the following: straight-chain, branched, or cyclic. As R 11 R 12 R 2 and R 3 Alkyl groups, for example, include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, and their hydroxy adducts (3-hydroxypropyl, etc.).

[0070] "Aryl group" refers to a group in which one hydrogen atom of an alkyl group is replaced by an aryl group. In general formulas (I), (II), and (III), the group constituting R... 11 R 12 R 2 and R 3 The alkyl group of an aralkyl group can be any of the following: straight-chain, branched, or cyclic. Examples of aralkyl groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylhexyl, and their hydroxy adducts.

[0071] The amino group in general formula (I) and the nitrogen-containing ring in general formulas (II) and (III) can form acid addition salts. Examples of acid addition salts include hydrochloride, hydrobromide, acetate, sulfate, nitrate, sulfite, phosphate, amide sulfate, and methanesulfonate.

[0072] From the perspective of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the perspective of easily suppressing the grinding speed of silicon oxide, polymer B can have structural units represented by general formula (I), or it can have R in general formula (I). 11 and R 12 It is the structural unit of the hydrogen atom.

[0073] R in general formulas (IV) and (V) 41 R 42 R 51 and R 52 The alkyl group can be any of the following: straight-chain, branched, or cyclic. As R 41 R 42 R 51 and R 52 Alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, and their hydroxy adducts (3-hydroxypropyl, etc.), are selected from the viewpoints of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and easily suppressing the polishing speed of silicon oxide. 41 R 42 R 51 and R 52 The number of carbon atoms in at least one alkyl group in the group can be 1 to 10, 1 to 7, 1 to 4, 1 to 3, or 1 to 2 or less.

[0074] The constituent R in general formulas (IV) and (V) 41 R 42 R 51 and R 52 The alkyl group of the aralkyl group can be any of the following: straight-chain, branched, or cyclic. As R 41 R 42 R 51 and R 52 Aryl groups include benzyl, phenethyl, phenylpropyl, phenylbutyl, and their hydroxy adducts.

[0075] From the perspective of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the perspective of easily suppressing the grinding speed of silicon oxide, polymer B can have structural units represented by general formula (IV), or it can have R in general formula (IV). 41 and R 42 It is a structural unit of the methyl group.

[0076] As D in general formulas (IV) and (V) - Cl can be cited as an example - ,Br - I - Halogen ions; alkyl sulfate ions such as methyl sulfate ion, ethyl sulfate ion, and dimethyl sulfate ion.

[0077] Examples of N,N-dialkylammonium salts and N-alkyl-N-benzylammonium salts include partial structures represented by general formula (IVa) in general formula (IV) and partial structures represented by general formula (Va) in general formula (V). Examples of N,N-dialkylammonium salts include N,N-dialkylammonium halides and N,N-dialkylammonium alkyl sulfates. Examples of N,N-dialkylammonium halides include N,N-dimethylammonium halide, N,N-diethylammonium halide, N,N-dipropylammonium halide, and N,N-dibutylammonium halide. Examples of N,N-dialkylammonium alkyl sulfates include N,N-dimethylammonium methyl sulfate and N,N-methylethylammonium ethyl sulfate. Examples of N-alkyl-N-benzylammonium salts include N-methyl-N-benzylammonium halide, N-ethyl-N-benzylammonium halide, and other N-alkyl-N-benzylammonium halides. Examples of halides that are part of the above-mentioned structure include chlorides, bromides, and iodides. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, polymer B may have at least one selected from the group consisting of N,N-dimethylammonium chloride and N,N-methylethylammonium ethyl sulfate as part of the above-mentioned structure.

[0078]

[0079] Polymer B can be a copolymer of an allylamine compound and a compound other than an allylamine compound. Polymer B can, for example, have a structure obtained by copolymerizing a monomer that provides the structural unit represented by general formula (IV) with a monomer other than an allylamine compound.

[0080] From the viewpoint of easily obtaining high grinding speeds of polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, polymer B can have structural units represented by the following general formula (VI), or structural units represented by general formula (IV) and structural units represented by general formula (VI).

[0081]

[0082] [In the formula, R] 6 This indicates a hydrogen atom or an alkyl group.

[0083] R in general formula (VI) 6From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, it can be at least one selected from the group consisting of hydrogen atoms and methyl groups, or it can be hydrogen atoms. Acrylamide and the like can be cited as monomers that provide the structural unit represented by general formula (VI).

[0084] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing grinding speeds for silicon oxide, polymer B may include at least one selected from the group consisting of diallyl methyl ammonium chloride-acrylamide copolymer and diallyl dimethyl ammonium chloride-acrylamide copolymer, as an allylamine polymer having a structural unit represented by general formula (VI).

[0085] From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, the molecular weight (e.g., weight-average molecular weight) of polymer B can be within the following ranges: The molecular weight of polymer B can be 1000 or more, 3000 or more, 5000 or more, 8000 or more, 10000 or more, 30000 or more, 50000 or more, 80000 or more, 100000 or more, 300000 or more, or 500000 or more. The weight-average molecular weight of polymer B can be 2000000 or less, 1500000 or less, 100000 or less, 800000 or less, 600000 or less, 500000 or less, 300000 or less, 100000 or less, 80000 or less, 50000 or less, 300000 or less, 15000 or less, less than 15000, 10000 or less, or 8000 or less. From these perspectives, the molecular weight of polymer B can be 1,000–2,000,000, 5,000–1,000,000, or 8,000–1,000,000. The molecular weight of polymer B can be determined in the same manner as that of polymer A.

[0086] When a specific cationic polymer contains polymer B, from the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing polishing speeds for silicon oxide, the content of polymer B in the cationic polymer or the specific cationic polymer can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99% by mass or more, or substantially 100% by mass (in the manner in which the cationic polymer or the specific cationic polymer is substantially formed of polymer B) based on the whole cationic polymer (the whole cationic polymer contained in the CMP polishing slurry) or the whole specific cationic polymer (the whole specific cationic polymer contained in the CMP polishing slurry).

[0087] The content of polymer B relative to 100 parts by weight of CMP polishing slurry can be within the following ranges. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the polishing speed of silicon oxide, the content of polymer B can be 0.00001 parts by weight or more, 0.00005 parts by weight or more, 0.0001 parts by weight or more, 0.0002 parts by weight or more, 0.0003 parts by weight or more, 0.0005 parts by weight or more, 0.0008 parts by weight or more, 0.001 parts by weight or more, 0.002 parts by weight or more, 0.0025 parts by weight or more, 0.003 parts by weight or more, 0.004 parts by weight or more, or 0.005 parts by weight or more. From the viewpoint of easily suppressing the polishing speed of silicon oxide, the content of polymer B can be 0.008 parts by weight or more, or 0.01 parts by weight or more. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, the content of polymer B can be 10 parts by weight or less, 5 parts by weight or less, 2.5 parts by weight or less, less than 2.5 parts by weight, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.1 parts by weight or less, 0.08 parts by weight or less, 0.05 parts by weight or less, 0.04 parts by weight or less, 0.03 parts by weight or less, 0.025 parts by weight or less, 0.02 parts by weight or less, 0.015 parts by weight or less, 0.012 parts by weight or less, or 0.01 parts by weight or less. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, the content of polymer B can be 0.008 parts by weight or less, or 0.005 parts by weight or less. From these perspectives, the content of polymer B can be 0.00001–10 parts by mass, 0.0001–1 part by mass, 0.001–0.01 parts by mass, or 0.005–0.01 parts by mass.

[0088] The ratio B of the abrasive content to the polymer B content can be within the following ranges. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, the ratio B can be 0.1 or more, 0.5 or more, 1 or more, more than 1, 2 or more, 3 or more, 5 or more, 8 or more, 10 or more, 15 or more, 20 or more, 25 or more, 30 or more, 33 or more, 40 or more, or 50 or more. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, the ratio B can be 60 or more, 62.5 or more, 67 or more, 80 or more, or 100 or more. From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the grinding speed of silicon oxide, the ratio B can be 1000 or less, 800 or less, 500 or less, 400 or less, 300 or less, 200 or less, 167 or less, 150 or less, 120 or less, or 100 or less. From the viewpoint of easily suppressing the grinding speed of silicon oxide, the ratio B can be 80 or less, 67 or less, 62.5 or less, 60 or less, or 50 or less. From these viewpoints, the ratio B can be 0.1 to 1000, 10 to 500, or 50 to 100.

[0089] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing grinding speeds for silicon oxide, the content of a specific cationic polymer (the content of polymer A and the total content of polymer B) relative to 100 parts by mass of CMP polishing slurry can be within the following range. The content of a specific cationic polymer can be 0.00001 parts by mass or more, 0.00005 parts by mass or more, 0.0001 parts by mass or more, 0.0002 parts by mass or more, 0.0003 parts by mass or more, 0.0005 parts by mass or more, 0.0008 parts by mass or more, 0.001 parts by mass or more, 0.002 parts by mass or more, 0.0025 parts by mass or more, 0.003 parts by mass or more, 0.004 parts by mass or more, 0.005 parts by mass or more, 0.008 parts by mass or more, 0.012 parts by mass or more, 0.015 parts by mass or more, 0.02 parts by mass or more, 0.025 parts by mass or more, 0.03 parts by mass or more, 0.05 parts by mass or more, 0.08 parts by mass or more, or 0.1 parts by mass or more. The content of a specific cationic polymer can be less than 10 parts by weight, less than 5 parts by weight, less than 2.5 parts by weight, less than 2.5 parts by weight, less than 2 parts by weight, less than 1 part by weight, less than 0.5 parts by weight, less than 0.1 parts by weight, less than 0.08 parts by weight, less than 0.05 parts by weight, less than 0.03 parts by weight, less than 0.025 parts by weight, less than 0.02 parts by weight, less than 0.015 parts by weight, less than 0.012 parts by weight, less than 0.01 parts by weight, less than 0.008 parts by weight, less than 0.005 parts by weight, less than 0.004 parts by weight, less than 0.003 parts by weight, or less than 0.0025 parts by weight. From these perspectives, the content of a specific cationic polymer can be 0.00001–10 parts by mass, 0.0001–1 part by mass, 0.001–0.01 parts by mass, 0.005–0.01 parts by mass, 0.0025–0.1 parts by mass, or 0.001–0.01 parts by mass.

[0090] From the viewpoint of easily obtaining high grinding speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing grinding speeds for silicon oxide, the ratio C of the abrasive content to the content of a specific cationic polymer (the total content of polymer A and polymer B) can be within the following range. The ratio C can be 0.1 or higher, 0.5 or higher, 1 or higher, more than 1, 2 or higher, 3 or higher, 5 or higher, 8 or higher, 10 or higher, 15 or higher, 20 or higher, 25 or higher, 30 or higher, 33 or higher, 40 or higher, 50 or higher, 60 or higher, 62.5 or higher, 67 or higher, 80 or higher, 100 or higher, 120 or higher, 150 or higher, 167 or higher, 200 or higher, 300 or higher, 400 or higher, or 500 or higher. The ratio C can be below 1000, below 800, below 500, below 400, below 300, below 200, below 167, below 150, below 120, below 100, below 80, below 67, below 62.5, below 60, below 50, below 40, below 33, below 30, below 25, below 20, below 15, below 10, below 8, or below 5. From these perspectives, the ratio C can be 0.1–1000, 1–500, 50–100, or 5–100.

[0091] (water)

[0092] The CMP polishing slurry involved in this embodiment can contain water. There are no particular limitations on the type of water, but it can be at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.

[0093] (Other ingredients)

[0094] The CMP polishing slurry described in this embodiment may contain other additives (excluding compounds equivalent to cationic polymers). Examples of additives include pH adjusters and pH buffers, water-soluble polymers, and nonionic surfactants, which will be described later.

[0095] Examples of water-soluble polymers include polyacrylic acid, polyacrylic acid copolymers, polyacrylates, and polyacrylic acid copolymer salts; polymethacrylic acid and polymethacrylate salts; polyacrylamide; polymethacrylamide; alginate, pectic acid, hydroxymethyl cellulose, agar, thermogelatinized polysaccharides, dextrin, cyclodextrin, and polyglucose; ethylene polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylaldehyde; glycerol polymers such as glycerol and glycerol derivatives; and polyethylene glycol.

[0096] Examples of nonionic surfactants include ether-type surfactants such as polyoxypropylene polyoxyethylene alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene ether derivatives, polyoxypropylene glycerol ethers, ethylene oxide adducts of polyethylene glycol, methoxy polyethylene glycol ethylene oxide adducts, and ethylene oxide adducts of acetylene glycols; ester-type surfactants such as dehydrated sorbitan fatty acid esters and glycerol borate fatty acid esters; amino ether-type surfactants such as polyoxyethylene alkylamines; ether ester-type surfactants such as polyoxyethylene dehydrated sorbitan fatty acid esters, polyoxyethylene glycerol borate fatty acid esters, and polyoxyethylene alkyl esters; alkanoyl amine-type surfactants such as fatty acid alkanoylamines and polyoxyethylene fatty acid alkanoylamines; ethylene oxide adducts of acetylene glycols; polyvinylpyrrolidone; polyacrylamide; polydimethylacrylamide; and polyvinyl alcohol.

[0097] In the CMP polishing slurry of this embodiment, the content of guanidine carbonate relative to 100 parts by weight of the CMP polishing slurry may be 0.001 parts by weight or less, less than 0.001 parts by weight, or less than 0.0001 parts by weight. The CMP polishing slurry of this embodiment may not contain guanidine carbonate (the content of guanidine carbonate may substantially be 0 parts by weight). The content of hydroxyalkyl cellulose relative to 100 parts by weight of the CMP polishing slurry may be 0.005 parts by weight or less, less than 0.005 parts by weight, or less than 0.001 parts by weight. The CMP polishing slurry of this embodiment may not contain hydroxyalkyl cellulose (the content of hydroxyalkyl cellulose may substantially be 0 parts by weight). The content of oxidant relative to 100 parts by weight of the CMP polishing slurry may be 0.01 parts by weight or less, less than 0.001 parts by weight, or less than 0.0001 parts by weight. The CMP polishing slurry of this embodiment may not contain oxidant (the content of oxidant may substantially be 0 parts by weight). The content of 4-pyranone compounds relative to 100 parts by weight of CMP polishing slurry can be less than 0.01 parts by weight, less than 0.01 parts by weight, less than 0.001 parts by weight, less than 0.001 parts by weight, or less than 0.0001 parts by weight. The CMP polishing slurry involved in this embodiment may not contain 4-pyranone compounds (the content of 4-pyranone compounds can substantially be 0 parts by weight). The content of aromatic polyoxyalkylene compounds relative to 100 parts by weight of CMP polishing slurry can be less than 0.1 parts by weight, less than 0.05 parts by weight, less than 0.005 parts by weight, less than 0.001 parts by weight, or less than 0.0001 parts by weight. The CMP polishing slurry involved in this embodiment may not contain aromatic polyoxyalkylene compounds (the content of aromatic polyoxyalkylene compounds can substantially be 0 parts by weight).

[0098] (pH)

[0099] The pH of the CMP polishing slurry involved in this embodiment can be within the following ranges. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, and from the viewpoint of easily suppressing the polishing speed of silicon oxide, the pH can be 10.0 or less, 9.5 or less, 9.0 or less, 8.0 or less, less than 8.0, 7.0 or less, less than 7.0, 6.5 or less, 6.0 or less, less than 6.0, 5.0 or less, less than 5.0, or 4.8 or less. From the viewpoint of easily obtaining high polishing speeds for polycrystalline silicon and silicon nitride, the pH can be 1.0 or more, 1.5 or more, 2.0 or more, 2.2 or more, 2.4 or more, 2.5 or more, 3.0 or more, more than 3.0, 3.2 or more, 3.5 or more, 3.8 or more, 4.0 or more, more than 4.0, 4.2 or more, 4.5 or more, or 4.8 or more. From these perspectives, pH can be 1.0–10.0, 1.0–8.0, 3.0–7.0, 3.5–6.0, or 2.0–5.0. pH is defined as the pH at a liquid temperature of 25°C.

[0100] The pH of the CMP polishing slurry described in this embodiment can be measured using a pH meter (e.g., HORIBA, Ltd., model F-51). For example, after calibrating the pH meter at three points using phthalate pH buffer (pH: 4.01), neutral phosphate pH buffer (pH: 6.86), and borate pH buffer (pH: 9.18) as standard buffers, the pH meter electrode is placed in the CMP polishing slurry, and the value is measured after stabilization for more than 3 minutes. At this time, the temperature of both the standard buffers and the CMP polishing slurry is set to 25°C.

[0101] The pH of a CMP polishing slurry can be varied depending on the type of compound used as an additive. Therefore, a CMP polishing slurry may contain a pH adjuster (excluding compounds equivalent to specific cationic polymers) to adjust the pH within the aforementioned range. Examples of pH adjusters include acidic and alkaline components. Examples of acidic components include organic acids such as propionic acid and acetic acid (excluding compounds equivalent to amino acids); inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; amino acids such as glycine; heterocyclic amines; and alkanolamines. Examples of alkaline components include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and tetramethylammonium hydroxide (TMAH). The CMP polishing slurry described in this embodiment may contain acidic components or organic acids. The CMP polishing slurry may contain a pH buffer to stabilize the pH. A buffer solution (a liquid containing a buffer) may be added. Examples of buffer solutions include acetate buffer and phthalate buffer. A CMP polishing slurry prepared without using a pH adjuster or pH buffer can be directly applied to CMP.

[0102] The CMP polishing slurry described in this embodiment can be stored as a single-component polishing slurry containing at least abrasive particles and a cationic polymer, or it can be stored as a multi-component (e.g., two-component) polishing slurry kit (CMP polishing slurry kit) by mixing a slurry (first liquid) and an additive liquid (second liquid) to separate the components of the CMP polishing slurry into a slurry and an additive liquid. The slurry, for example, contains at least abrasive particles and water. The additive liquid, for example, contains at least a cationic polymer and water.

[0103] In the aforementioned polishing slurry kit, the slurry and additives are mixed to prepare the CMP polishing slurry before or during polishing. Furthermore, the single-component polishing slurry can be stored as a storage solution with reduced water content and can be diluted with water during polishing. The multi-component polishing slurry kit can be stored as both a slurry storage solution and an additive storage solution with reduced water content and can be diluted with water during polishing.

[0104] <Grinding Method>

[0105] The polishing method according to this embodiment includes a polishing step of polishing a workpiece using a CMP polishing slurry according to this embodiment. The polishing step can be a step of polishing a workpiece having a substrate on its surface using a CMP polishing slurry according to this embodiment. The polishing step can be a step of polishing the workpiece using a polishing component while supplying the CMP polishing slurry according to this embodiment between the workpiece and a polishing component (polishing pad, etc.). The workpiece may contain at least one selected from the group consisting of polycrystalline silicon, silicon nitride, and silicon oxide, and may also contain polycrystalline silicon. The polishing step, for example, is a step of planarizing a substrate having the workpiece on its surface using CMP technology by adjusting the content, pH, etc., of a CMP polishing slurry. The workpiece may be in the form of a film (polished film), or it may be a polycrystalline silicon film, a silicon nitride film, a silicon oxide film, etc.

[0106] The polishing method described in this embodiment is suitable for polishing a substrate with a polishing material on its surface during the manufacturing process of the following devices. Examples of such devices include individual semiconductors such as diodes, transistors, compound semiconductors, thermistors, rheostats, and thyristors; storage elements such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), Mask ROM (Mask Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), and flash memory; theoretical circuit elements such as microprocessors, DSPs (Digital Signal Processing), and ASICs (Application-Specific Integrated Circuits); integrated circuit elements such as compound semiconductors, represented by MMICs (Monolithic Microwave Integrated Circuits); and photoelectric conversion elements such as hybrid integrated circuits (hybrid ICs), light-emitting diodes, and charge-coupled devices.

[0107] The polishing method described in this embodiment is suitable for polishing surfaces in substrates with stepped (uneven) surfaces. Examples of substrates include logic semiconductor devices and memory semiconductor devices. The polished material can be a material with steps of 1 μm or more in height, or a material with T-shaped or grid-like portions when viewed from above. For example, the object to be polished can be a semiconductor substrate with memory cells. According to this embodiment, it is also possible to polish the polished material disposed on the surface of a semiconductor device (DRAM, flash memory, etc.) having a semiconductor substrate with memory cells at a high polishing speed. According to this embodiment, the polished material disposed on the surface of a 3D-NAND flash memory can also be polished at a high polishing speed while ensuring high flatness. In addition to polysilicon, silicon nitride, or silicon oxide, the polished material of the substrate can also include Al, Cu, Ti, TiN, W, Ta, TaN, etc.

[0108] As a polishing apparatus, for example, a device preferably includes a holder for holding the substrate, a polishing plate to which the polishing pad is attached, and a mechanism for supplying CMP polishing slurry to the polishing pad. Examples of polishing apparatuses include those manufactured by EBARA CORPORATION (models: EPO-111, EPO-222, FREX200, FREX300, etc.) and those manufactured by APPLIED MATERIALS (trade names: Mirra3400, Reflexion, etc.).

[0109] As a polishing pad, general non-woven fabrics, foams, and non-foamed materials can be used. As a material for the polishing pad, resins such as polyurethane, acrylic resin, polyester, acrylate copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly4-methylpentene, cellulose, cellulose ester, polyamide (e.g., nylon and aramid), polyimide, polyimide amide, polysiloxane copolymer, ethylene oxide compounds, phenolic resin, polystyrene, polycarbonate, and epoxy resin can be used. As a material for the polishing pad, especially from the viewpoint of further improving polishing speed and flatness, at least one material selected from the group consisting of foamed polyurethane and non-foamed polyurethane can be used. The polishing pad can be subjected to a grooving process similar to that used for storing CMP polishing fluid.

[0110] There are no particular restrictions on grinding conditions; from the perspective of suppressing substrate ejection, the grinding plate rotation speed can be 200 rpm (min). -1 From the viewpoint of easily suppressing damage to the surface being polished, the pressure (processing load) applied to the substrate can be 100 kPa or less. During polishing, CMP polishing fluid can be continuously supplied to the polishing pad using a pump or the like. There is no particular limitation on the supply amount, but the surface of the polishing pad can always be covered with CMP polishing fluid.

[0111] After grinding, the substrate can be thoroughly cleaned in running water, and then wiped dry with a rotary dryer or similar device to remove any water droplets adhering to the substrate.

[0112] By grinding in this way, surface irregularities can be eliminated, resulting in a smooth surface across the entire substrate. By repeatedly forming the material to be ground and grinding a predetermined number of times, a substrate with the desired number of layers can be manufactured.

[0113] The substrates obtained in this way can be used for various electronic and mechanical parts. Specific examples include semiconductor components; optical glass such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, and optical waveguides made of glass and crystalline materials; optical single crystals such as fiber optic end faces and scintillators; solid-state laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for hard disk drives; and magnetic heads.

[0114] The manufacturing method of the part according to this embodiment includes a wafer-leveling step of wafer-leveling a substrate polished by the polishing method according to this embodiment. The substrate may be at least one selected from the group consisting of polysilicon, silicon nitride, and silicon oxide. Examples of substrates include wafers (e.g., semiconductor wafers). The wafer-leveling step may be, for example, a step of dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain a wafer (e.g., a semiconductor wafer). The manufacturing method of the part according to this embodiment may include a step of polishing the substrate by the polishing method according to this embodiment before the wafer-leveling step. The part according to this embodiment is, for example, a wafer (e.g., a semiconductor wafer). The part according to this embodiment is a part obtained by the manufacturing method of the part according to this embodiment. The electronic device according to this embodiment includes the part according to this embodiment.

[0115] Example

[0116] The present invention will be further described in detail below with reference to embodiments, but the present invention is not limited to these embodiments. For example, the types and proportions of materials in the CMP polishing slurry may be other than those described in this embodiment, and the composition and structure of the polishing object may also be other than those described in this embodiment.

[0117] <Preparation of Abrasive Grains>

[0118] (Cerium oxide particles)

[0119] 40 kg of cerium carbonate hydrate was placed in an alumina container and calcined in air at 830°C for 2 hours to obtain 20 kg of yellowish-white powder. X-ray diffraction (XRD) analysis confirmed the presence of polycrystalline cerium oxide. SEM observation of the particle size of the calcined powder showed a range of 20–100 μm. The 20 kg of cerium oxide powder was then dry-milled using a jet mill. SEM observation of the milled cerium oxide powder confirmed the presence of polycrystalline cerium oxide particles with grain boundaries. Furthermore, the specific surface area of ​​the cerium oxide powder was 9.4 m². 2 / g. The specific surface area was determined using the BET method.

[0120] 15 kg of the aforementioned cerium oxide powder and 84.7 kg of deionized water were placed in a container and mixed. Then, 0.3 kg of a 1N acetic acid aqueous solution was added and the mixture was stirred for 10 minutes, thus obtaining a cerium oxide mixture. After 30 minutes, the cerium oxide mixture was transferred to another container. During this time, the cerium oxide mixture was ultrasonically irradiated at a frequency of 400 kHz within the transfer piping.

[0121] 500 g of cerium oxide mixture was collected in four 500 mL beakers and centrifuged. Centrifugation was performed for 2 minutes at a centrifugal force of 500 G applied to the periphery. Cerium oxide particles (cerium-oxygen particles, abrasive grains) settled at the bottom of the beakers were recovered, and the supernatant was collected. The average particle size of the cerium oxide particles in the 5% by mass dispersion was determined using a laser diffraction / scattering particle size analyzer (manufactured by HORIBA, Ltd., trade name: LA-920), and the average particle size was found to be 90 nm.

[0122] (Silicon oxide particles)

[0123] As silica particles (silica particles, abrasive grains), a product manufactured by FUSO CHEMICAL CO.,LTD under the trade name "PL-3" was prepared. The average particle size of the silica particles in a dispersion containing 5% by mass was determined using a laser diffraction / scattering particle size analyzer (manufactured by HORIBA,Ltd., trade name: LA-920), and the result was an average particle size of 70 nm.

[0124] <Preparation of CMP Grinding Slurry>

[0125] The CMP polishing slurries of each example and Comparative Examples 2 to 4 were obtained by mixing the abrasive particles (cerium oxide particles or silicon oxide particles) described in Tables 1 to 4, a cationic polymer, and deionized water. The CMP polishing slurry of Comparative Example 1 was obtained by mixing the cerium oxide particles and deionized water. The contents of the abrasive particles and the cationic polymer (reference: total amount of CMP polishing slurry) are shown in Tables 1 to 4. When the cationic polymer was supplied using an aqueous polymer solution, the content of the cationic polymer was calculated based on the mass of the polymer in the aqueous polymer solution. The following compound was used as the cationic polymer.

[0126] (Catonic polymer)

[0127] [Specific cationic polymers]

[0128] A1: Dimethylamine / ammonia / epoxychloropropane condensate (manufactured by SENKA corporation, trade name: UnisenseKHE100L, weight average molecular weight: 7056 (measured value))

[0129] A2: Dimethylamine / ammonia / epoxychloropropane condensate (manufactured by SENKA corporation, trade name: UnisenseKHE102L, weight average molecular weight: 53336 (measured value))

[0130] A3: Dimethylamine / ammonia / epoxychloropropane condensate (manufactured by SENKA corporation, trade name: UnisenseKHE105L, weight average molecular weight: 479796 (measured value))

[0131] A4: Dimethylamine / ammonia / epoxychloropropane condensate (manufactured by SENKA corporation, trade name: UnisenseKHE1000L, weight average molecular weight: 1296145 (measured value))

[0132] A5: Dimethylamine / epoxychloropropane condensate (manufactured by SENKA corporation, trade name: UnisenseKHE104L)

[0133] B1: Diallyl dimethylammonium chloride condensate (manufactured by SENKA corporation, trade name: Unisense FPA1002L, a polymer having structural units represented by the above general formula (IV))

[0134] B2: Diallyl dimethylammonium chloride-acrylamide copolymer (manufactured by NITTOBO MEDICALCO.,LTD., trade name: PAS-J-81, a polymer having structural units represented by the above general formula (IV) and structural units represented by the above general formula (VI))

[0135] B3: Allylamine polymer (manufactured by NITTOBO MEDICAL CO.,LTD., trade name: PAA-08, a polymer having structural units represented by the above general formula (I))

[0136] [Catonic polymers that do not conform to specific cationic polymer characteristics]

[0137] X1: Trimethylaminoethyl methyl methacrylate polymer (manufactured by SENKA corporation, trade name: Unisense FPV1000L)

[0138] X2: Polyalkylene glycol modified styrene-maleic acid copolymer (manufactured by KYOEISHA CHEMICAL Co.,LTD., trade name: Floren GW-1500)

[0139] X3: Polyoxyethylene polyoxypropylene glycerol ether (manufactured by AOKI OIL INDUSTRIAL Co., Ltd., trade name: GEP-2500, EO / PO = 30 / 70)

[0140] The weight-average molecular weights of the aforementioned specific cationic polymers A1–A4 were determined by gel permeation chromatography (GPC) under the following conditions, based on a standard curve using standard polystyrene. The calibration curve was approximated using standard polyethylene oxide (manufactured by TOSOH CORPORATION, SE-2, SE-5, SE-30, and SE-150), pullulan (manufactured by PSS, pss-dpul 2.5m), and polyethylene glycol (manufactured by FUJIFILM Wako Pure Chemical Corporation, PEG400, PEG1000, PEG3000, and PEG6000) in a cubic equation.

[0141] Pump: Manufactured by SHIMADZU CORPORATION, product name "LC-20AD"

[0142] Detector: Manufactured by SHIMADZU CORPORATION, trade name "RID-10A"

[0143] Column oven: Manufactured by SHIMADZU CORPORATION, product name "CTO-20AC"

[0144] Column: Two TOSOH CORPORATION manufactured products under the trade name "TSKGel G6000PW" XL -CP connected in series

[0145] Tube string dimensions: 7.8mm I.D × 300mm

[0146] Eluent: 0.1M sodium nitrate aqueous solution

[0147] Sample concentration: 4 mg / 2 mL (NV conversion)

[0148] Injection volume: 100μL

[0149] Flow rate: 1.0 mL / min

[0150] Measurement temperature: 25℃

[0151] The average particle size of the abrasive particles in the CMP polishing slurry was determined using a laser diffraction / scattering particle size analyzer (manufactured by HORIBA, Ltd., trade name: LA-920). The results showed that the average particle size of cerium oxide particles was 90 nm and the average particle size of silicon oxide particles was 70 nm.

[0152] The pH of the CMP slurry was determined under the following conditions. The results are shown in Tables 1–4.

[0153] Measurement temperature: 25℃

[0154] Measuring device: Manufactured by HORIBA, Ltd., model F-51

[0155] Measurement method: After three-point calibration using standard buffers (phthalate pH buffer, pH: 4.01 (25℃); neutral phosphate pH buffer, pH: 6.86 (25℃); borate pH buffer, pH: 9.18), the electrode was placed in CMP grinding slurry, and the pH was measured after more than 3 minutes of stabilization using the above-mentioned measuring device.

[0156] <Evaluation of Grinding Characteristics>

[0157] Blanket wafers having a polishing film (polysilicon film, silicon nitride film, or silicon oxide film) on their surface were polished using the aforementioned CMP polishing slurries under the following polishing conditions. As blanket wafers, wafers having a 200 nm thick polysilicon film disposed on a 300 mm diameter silicon substrate, wafers having a 300 nm thick silicon nitride film disposed on a 300 mm diameter silicon substrate, and wafers having a 1000 nm thick silicon oxide film (silicon dioxide film) disposed on a 300 mm diameter silicon substrate were used. After polishing the polysilicon film using an aqueous dispersion of abrasive particles, polishing of the polysilicon film using the aforementioned CMP polishing slurries was performed.

[0158] [Grinding conditions]

[0159] Grinding equipment: CMP grinder, manufactured by Reflexion-LK (Applied Materials, Inc.)

[0160] Abrasive pad: Porous polyurethane pad IC-1010 (manufactured by DuPont)

[0161] Grinding pressure (load): 3.0 psi

[0162] Plate rotation speed: 93 rpm

[0163] Grinding head speed: 87 rpm

[0164] CMP slurry supply rate: 125 mL / min

[0165] Polishing time: 15 seconds (polycrystalline silicon), 15 seconds (silicon nitride), 30 seconds (silicon oxide)

[0166] Using an optical interferometric film thickness measurement device (NOVA i500) manufactured by Nova Measuring Instruments, the film thickness of the films being polished (polycrystalline silicon, silicon nitride, and silicon oxide) before and after polishing was measured, and the change in film thickness was calculated. The film thickness was measured at 79 points, and the change in film thickness was calculated using the average value. Based on the change in film thickness and polishing time, the polishing speed (blanket-type wafer polishing speed) was calculated using the following formula. Furthermore, the polishing speed ratios of polycrystalline silicon to silicon oxide and silicon nitride to silicon oxide were calculated. The results are shown in Tables 1-4. It can be seen that a high polishing speed for polycrystalline silicon can be obtained by using a specific cationic polymer.

[0167]

[0168] [Table 1]

[0169]

[0170] [Table 2]

[0171]

[0172] [Table 3]

[0173]

[0174] [Table 4]

[0175]

Claims

1. A polishing method, which is a method of polishing polycrystalline silicon using CMP polishing slurry. The CMP polishing slurry contains abrasive particles and cationic polymers. The cationic polymer comprises at least one polymer selected from the group consisting of polymer A having a main chain containing nitrogen and carbon atoms and hydroxyl groups bonded to the carbon atoms and allylamine polymer B. When the cationic polymer comprises polymer B, polymer B has at least one structural unit selected from the group consisting of structural units represented by general formula (I), general formula (II), general formula (III), general formula (IV), and general formula (V). In general formula (I), R 11 and R 12 Each independently represents a hydrogen atom, alkyl group, or aralkyl group; the amino group may or may not form an acid addition salt; in general formula (II), R 2 Represents a hydrogen atom, alkyl or aralkyl group, containing a nitrogen ring that may or may not form an acid addition salt; in general formula (III), R 3 Represents a hydrogen atom, alkyl or aralkyl group, containing a nitrogen ring that may or may not form an acid addition salt; in general formula (IV), R 41 and R 42 Each independently represents a hydrogen atom, alkyl group, or aralkyl group, D - R represents a monovalent anion; in the general formula (V), R 51 and R 52 Each independently represents a hydrogen atom, alkyl group, or aralkyl group, D - This represents a monovalent anion.

2. The grinding method according to claim 1, wherein, The cationic polymer includes polymer A.

3. The grinding method according to claim 2, wherein, The polymer A has multiple structural units having the main chain.

4. The grinding method according to claim 2, wherein, The polymer A comprises the nitrogen atom and an alkylene chain bonded to the nitrogen atom. The hydroxyl group is bonded to the carbon atom of the alkylene chain.

5. The grinding method according to claim 4, wherein, The alkylene chain has 3 to 4 carbon atoms.

6. The grinding method according to claim 2, wherein, The polymer A contains nitrogen atoms that constitute a quaternary ammonium salt.

7. The grinding method according to claim 6, wherein, The quaternary ammonium salt contains nitrogen atoms bonded by two methyl groups.

8. The grinding method according to claim 2, wherein, The polymer A contains nitrogen atoms that constitute an acid addition salt.

9. The grinding method according to claim 2, wherein, The polymer A contains nitrogen atoms that constitute the hydrochloride salt.

10. The grinding method according to claim 2, wherein, The polymer A comprises structural units having a hydrocarbon group between the nitrogen atom and the carbon atom bonded to the hydroxyl group as structural units having the main chain.

11. The grinding method according to claim 2, wherein, The polymer A comprises a reactant containing at least dimethylamine and epichlorohydrin.

12. The grinding method according to claim 2, wherein, The polymer A comprises a reactant containing at least dimethylamine, ammonia, and epichlorohydrin.

13. The grinding method according to claim 2, wherein, The polymer A comprises a compound having a structure represented by the following formula, In the formula, a represents an integer greater than or equal to 1, and b represents an integer greater than or equal to 0.

14. The grinding method according to claim 2, wherein, The polymer A comprises at least one selected from the group consisting of dimethylamine / epoxychloropropane condensate and dimethylamine / ammonia / epoxychloropropane condensate.

15. The grinding method according to claim 2, wherein, The weight-average molecular weight of polymer A is 5,000 to 1,500,000.

16. The grinding method according to claim 2, wherein, The weight-average molecular weight of polymer A is 100,000 to 500,000.

17. The grinding method according to claim 2, wherein, The content of polymer A is 0.00001 to 10 parts by weight relative to 100 parts by weight of the CMP polishing slurry.

18. The grinding method according to claim 2, wherein, The content of polymer A is 0.001 to 0.1 parts by mass relative to 100 parts by mass of the CMP polishing slurry.

19. The grinding method according to claim 2, wherein, The ratio of the content of the abrasive particles to the content of the polymer A is 0.1 to 1000.

20. The grinding method according to claim 2, wherein, The ratio of the content of the abrasive particles to the content of the polymer A is 5 to 100.

21. The grinding method according to claim 1, wherein, The cationic polymer comprises the allylamine polymer B.

22. The grinding method according to claim 21, wherein, The allylamine polymer B comprises a polymer having diallyl dialkylammonium salt as a monomer unit.

23. The grinding method according to claim 21, wherein, The polymer B has R in the general formula (I) 11 and R 12 It is the structural unit of the hydrogen atom.

24. The grinding method according to claim 21, wherein, The polymer B has R in the general formula (IV). 41 and R 42 It is a structural unit of the methyl group.

25. The grinding method according to claim 21, wherein, The polymer B has at least one selected from the group consisting of N,N-dimethylammonium chloride and N,N-methylethylammonium ethyl sulfate.

26. The grinding method according to claim 21, wherein, The polymer B has structural units represented by the following general formula (VI), In the formula, R 6 It represents a hydrogen atom or an alkyl group.

27. The grinding method according to claim 21, wherein, The polymer B comprises at least one selected from the group consisting of diallyl methyl ammonium chloride-acrylamide copolymer and diallyl dimethyl ammonium chloride-acrylamide copolymer.

28. The grinding method according to claim 21, wherein, The weight-average molecular weight of polymer B is 1,000 to 2,000,000.

29. The grinding method according to claim 21, wherein, The weight-average molecular weight of polymer B is 8,000 to 1,000,000.

30. The grinding method according to claim 21, wherein, The content of polymer B is 0.00001 to 10 parts by weight relative to 100 parts by weight of CMP polishing slurry.

31. The grinding method according to claim 21, wherein, The content of polymer B is 0.001 to 0.01 parts by mass relative to 100 parts by mass of the CMP polishing slurry.

32. The grinding method according to claim 21, wherein, The ratio of the content of the abrasive particles to the content of the polymer B is 0.1 to 1000.

33. The grinding method according to claim 21, wherein, The ratio of the content of the abrasive particles to the content of the polymer B is 50 to 100.

34. The grinding method according to any one of claims 1 to 33, wherein, The abrasive grains comprise at least one selected from the group consisting of cerium compounds, alumina, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, mullite, silicon nitride, aluminum nitride, titanium nitride, silicon carbide, and boron carbide.

35. The grinding method according to any one of claims 1 to 33, wherein, The abrasive grains contain α-silicon nitride.

36. The grinding method according to any one of claims 1 to 33, wherein, The abrasive grains contain cerium-based compounds.

37. The grinding method according to claim 36, wherein, The cerium compounds include cerium oxide.

38. The grinding method according to any one of claims 1 to 33, wherein, The abrasive grains do not contain hydroxides.

39. The grinding method according to any one of claims 1 to 33, wherein, The average particle size of the abrasive grains is 50~500nm.

40. The grinding method according to any one of claims 1 to 33, wherein, The content of the abrasive particles is 0.01 to 10 parts by mass relative to 100 parts by mass of the CMP polishing slurry.

41. The grinding method according to any one of claims 1 to 33, wherein, The content of the abrasive particles is 0.1 to 2 parts by mass relative to 100 parts by mass of the CMP polishing slurry.

42. The grinding method according to any one of claims 1 to 33, wherein, pH below 7.

0.

43. The grinding method according to any one of claims 1 to 33, wherein, pH range: 2.0 to 5.

0.

44. The grinding method according to any one of claims 1 to 33, wherein, The CMP polishing slurry is prepared by mixing the first and second liquids, resulting in a multi-liquid polishing slurry kit consisting of the first and second liquids. The first liquid contains at least the abrasive particles and water. The second liquid contains at least the cationic polymer and water.

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