Acidified gypsum membrane grinding solution composition

Abstract

To provide a polishing liquid composition for silicon oxide film that can achieve both improvement of polishing speed of silicon oxide film and reduction of line width dependence of polishing speed in concavo-convex pattern.SOLUTION: The present disclosure relates, in one aspect, to a polishing liquid composition for silicon oxide film that contains a cerium oxide particle (component A), a compound represented by the following formula (I) or formula (II) (component B), a nitrogen-containing heteroaromatic compound (component C) in which at least one hydrogen atom is substituted with a hydroxyl group, and an aqueous medium.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a polishing composition for silicon oxide films, and a method for producing and polishing semiconductor substrates using the same. [Background technology]

[0002] In recent years, semiconductor elements have become increasingly multilayered and highly precise, and finer pattern formation techniques have come to be used. Accordingly, the surface structure of semiconductor elements has become more complex, and the surface steps have also become larger. When manufacturing semiconductor elements, chemical mechanical polishing (CMP) technology is used as a technique for flattening steps (surface irregularities) formed on a substrate. As the degree of precision increases, polishing compositions that can polish at high speed while providing good flatness are increasingly desired.

[0003] For example, Patent Document 1 proposes a polishing composition for silicon oxide films that contains cerium oxide particles, a nitrogen-containing heteroaromatic ring compound such as 2-hydroxypyridine N-oxide, and an aqueous medium. Patent Document 2 proposes a polishing composition containing a pyrrolidone polymer (for example, polyvinylpyrrolidone), an aminophosphonic acid, a tetraalkylammonium salt, and water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-80399 [Patent Document 2] Special table 2015-534725 publication Summary of the Invention [Problem to be solved by the invention]

[0005] As semiconductor devices become increasingly multi-layered and highly precise, there is a demand for further improvements in the polishing speed of silicon oxide films (films to be polished) in CMP polishing to eliminate the steps that result from the increased stacking. Furthermore, when polishing a concave-convex pattern formed on a substrate, there is a problem that the polishing rate varies depending on the size (line width) of the convex portions, and the polishing rate of the convex portions is highly dependent on the line width. Therefore, there is a need for a polishing composition that minimizes the dependency of the polishing rate of the convex portions on the line width and can uniformly planarize any pattern.

[0006] Patent Document 1 discloses a polishing composition containing a nitrogen-containing heteroaromatic ring compound (e.g., 2-hydroxypyridine N-oxide) that is effective in improving the polishing rate for narrow wiring. However, increasing the amount of the compound added to improve the polishing rate tends to decrease the polishing rate for wide wiring, so it is desirable to reduce the line width dependency. Patent Document 2 discloses a polishing composition containing a pyrrolidone polymer. Although the slurry stability of this polishing composition is good, its effect of improving the removal rate is still not fully satisfactory.

[0007] Therefore, the present disclosure provides a polishing composition for silicon oxide films that can improve the polishing rate of silicon oxide films and reduce the line width dependency of the polishing rate in a concave-convex pattern, as well as a method for manufacturing and polishing a semiconductor substrate using the same. [Means for solving the problem]

[0008] In one aspect, the present disclosure relates to a polishing composition for silicon oxide films, which contains cerium oxide particles (component A), a compound represented by the following formula (I) or formula (II) (component B), a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom has been substituted with a hydroxyl group (component C), and an aqueous medium. [ka] In the formula (I), R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3are H, -NH2, -NHCH3, -N(CH3)2, -N + (CH3)3, an alkyl group, a phenyl group, a cytidine group, a guanidino group, or an alkylguanidino group; X 1 represents a bond or an alkylene group having 1 to 12 carbon atoms, and n represents 0 or 1. In the formula (II), R 4 and R 5 are the same or different and represent a hydroxyl group or a salt thereof; Z 1 is H or -N + (CH3)3, Z 2 indicates a cytidine group, and X 2 represents a bond or an alkylene group having 1 to 12 carbon atoms, and n1 and n2 are the same or different and represent 0 or 1.

[0009] In one aspect, the present disclosure relates to a method for producing a semiconductor substrate, which includes a step of polishing a film to be polished with the polishing composition for a silicon oxide film of the present disclosure.

[0010] In one aspect, the present disclosure relates to a polishing method comprising a step of polishing a film to be polished with the polishing composition of the present disclosure, wherein the film to be polished is a silicon oxide film formed during the manufacturing process of a semiconductor substrate. [Effects of the Invention]

[0011] According to one aspect of the present disclosure, it is possible to provide a polishing composition for silicon oxide films that can improve the polishing rate for silicon oxide films and reduce the line width dependency of the polishing rate in a concave-convex pattern. DETAILED DESCRIPTION OF THE INVENTION

[0012] As a result of extensive research by the present inventors, it has been found that the combined use of a specific compound and a specific nitrogen-containing heteroaromatic compound can improve the polishing rate for a silicon oxide film, reduce the line width dependency of the polishing rate in a concave-convex pattern, and improve flatness.

[0013] That is, in one aspect, the present disclosure relates to a polishing composition for silicon oxide films (hereinafter also referred to as the "polishing composition of the present disclosure") containing cerium oxide particles (component A), a compound represented by the above formula (I) or formula (II) (component B), a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom has been substituted with a hydroxyl group (component C), and an aqueous medium.

[0014] According to one or more embodiments, the polishing composition of the present disclosure can achieve both an improvement in the removal rate of a silicon oxide film and a reduction in the line width dependency of the removal rate in a concave-convex pattern (improvement of flatness).

[0015] Although the details of the mechanism by which the effects of the present disclosure are manifested are not clear, it is presumed as follows. It is known that a specific nitrogen-containing heteroaromatic compound (ingredient C) reduces cerium oxide particles, promoting electron transfer to the silicon oxide film, which is the object to be polished, and increasing the chemical polishing power. Adding ingredient C increases the polishing rate. However, ingredient C also has another function: it adsorbs to the silicon oxide film, exhibiting a polishing suppression ability. Therefore, if the amount of ingredient C added is increased to improve the polishing rate, a problem occurs in that the polishing rate decreases significantly, especially on convex parts with wide line widths. To further improve the polishing rate, a chemical other than ingredient C that can improve the polishing rate on convex parts with wide line widths has been needed. In the present disclosure, it has been discovered that Component B's strong interaction with cerium oxide contributes to an improvement in the polishing rate for convex portions with a wide line width, i.e., it is possible to reduce the line width dependency caused by Component C. Although the details are not clear, it is thought that Component B increases the frequency of contact of cerium oxide particles with the (100) plane, and Component C promotes electron transfer and polishing progress particularly between the (100) plane of the cerium oxide particles and the silicon oxide film, thereby improving the polishing rate and flatness. However, the present disclosure need not be construed as being limited to these mechanisms.

[0016] [Cerium oxide particles (component A)] The polishing liquid composition of the present disclosure contains cerium oxide (hereinafter also referred to as "ceria") particles (hereinafter also simply referred to as "component A") as polishing abrasive grains. Component A can be positively charged ceria or negatively charged ceria. The chargeability of component A can be confirmed, for example, by measuring the potential (surface potential) on the surface of the abrasive grains determined by an electroacoustic method (ESA method: Electrokinetic Sonic Amplitude). The surface potential can be measured, for example, using a "Zeta Probe" (manufactured by Kyowa Interface Science Co., Ltd.), specifically, by the method described in the Examples. Component A may be one type or a combination of two or more types. Component A may be one type or a combination of two or more types. The chargeability of the abrasive grains is not limited, but positively charged ceria is preferred from the viewpoint of improving the polishing rate.

[0017] The manufacturing method, shape, and surface condition of Component A are not particularly limited. Examples of Component A include colloidal ceria, amorphous ceria, and ceria-coated silica. Colloidal ceria can be obtained by a build-up process, for example, using the method described in Examples 1 to 4 of JP-A 2010-505735. Examples of amorphous ceria include pulverized ceria. One embodiment of pulverized ceria includes calcined pulverized ceria obtained by calcining and pulverizing a cerium compound such as cerium carbonate or cerium nitrate. Another embodiment of pulverized ceria includes single-crystal pulverized ceria obtained by wet-pulverizing ceria particles in the presence of an inorganic or organic acid. Examples of inorganic acids used in wet-pulverization include nitric acid, and examples of organic acids include organic acids having a carboxyl group. Specific examples include at least one selected from polycarboxylates such as ammonium polyacrylate, picolinic acid, glutamic acid, aspartic acid, aminobenzoic acid, and p-hydroxybenzoic acid. For example, using at least one selected from picolinic acid, glutamic acid, aspartic acid, aminobenzoic acid, and p-hydroxybenzoic acid during wet milling can produce positively charged ceria, while using a polycarboxylate such as ammonium polyacrylate during wet milling can produce negatively charged ceria. Examples of wet milling methods include wet milling using a planetary bead mill. Examples of ceria-coated silica include composite particles having a structure in which at least a portion of the surface of silica particles is coated with granular ceria, as described in Examples 1 to 14 of JP 2015-63451 A or Examples 1 to 4 of JP 2013-119131 A. These composite particles can be obtained, for example, by depositing ceria on silica particles.

[0018] Examples of the shape of component A include substantially spherical, polyhedral, and raspberry shapes.

[0019] The average primary particle diameter of component A is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more, from the viewpoint of improving the polishing rate and improving the flatness, and is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, even more preferably 100 nm or less, and even more preferably 50 nm or less, from the viewpoint of suppressing the occurrence of polishing scratches. In the present disclosure, the average primary particle diameter of component A is determined by the BET specific surface area S (m 2 The BET specific surface area can be measured by the method described in the Examples.

[0020] From the viewpoint of improving the polishing rate and improving flatness, the content of component A in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.125% by mass or more, and even more preferably 0.15% by mass or more, and from the viewpoint of suppressing the occurrence of polishing scratches, the content is preferably 6% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less. The content of Component A in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 6% by mass or less, more preferably 0.01% by mass or more and 6% by mass or less, even more preferably 0.05% by mass or more and 3% by mass or less, even more preferably 0.1% by mass or more and 1% by mass or less, even more preferably 0.125% by mass or more and 0.5% by mass or less, and even more preferably 0.15% by mass or more and 0.3% by mass or less. When Component A is a combination of two or more types, the content of Component A refers to the total content thereof.

[0021] [Compound represented by formula (I) or formula (II) (Component B)] The polishing composition of the present disclosure contains a compound represented by the following formula (I) or (II) (hereinafter also simply referred to as "component B"). Component B may be one type or a combination of two or more types.

[0022] [ka]

[0023] In the formula (I), R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 are H, -NH2, -NHCH3, -N(CH3)2, -N + (CH3)3, an alkyl group, a phenyl group, a cytidine group, a guanidino group, or an alkylguanidino group; X 1 represents a bond or an alkylene group having 1 to 12 carbon atoms, and n represents 0 or 1. In the formula (II), R 4 and R 5 are the same or different and represent a hydroxyl group or a salt thereof; Z 1 is H or -N + (CH3)3, Z 2 indicates a cytidine group, and X 2 represents a bond or an alkylene group having 1 to 12 carbon atoms, and n1 and n2 are the same or different and represent 0 or 1.

[0024] In formula (I), R 1 and R 2 and are preferably hydroxyl groups from the viewpoints of reducing salt concentration and improving stability. R 3 From the viewpoint of improving the polishing speed and flatness, H, -NH2, -N + (CH3)3, an alkyl group, a phenyl group, a cytidine group, or an alkylguanidino group is preferred. R 3 is preferably a phenyl group, a cytidine group, or a guanidino group, and more preferably a phenyl group, from the viewpoint of reducing line width dependency. As the alkyl group, from the viewpoint of improving the polishing rate and improving flatness, an alkyl group having 1 to 12 carbon atoms is preferred, an alkyl group having 2 to 6 carbon atoms is more preferred, and an alkyl group having 4 carbon atoms (butyl group) is even more preferred. As the alkylguanidino group, from the viewpoint of improving the polishing rate and improving flatness, an alkylguanidino group having 2 to 12 carbon atoms is more preferred, an alkylguanidino group having 2 to 4 carbon atoms is even more preferred, a methylguanidino group is even more preferred, and a 1-methylguanidino group is even more preferred. X 1 From the viewpoint of improving solubility, is preferably a bond or an alkylene group having 12 or less carbon atoms, more preferably a bond or an alkylene group having 10 or less carbon atoms, even more preferably a bond or an alkylene group having 8 or less carbon atoms, even more preferably a bond or an alkylene group having 6 or less carbon atoms, preferably a bond or an alkylene group having 4 or less carbon atoms, even more preferably a bond or an alkylene group having 2 carbon atoms (ethylene group), and even more preferably a bond. In formula (I), in one or more embodiments, from the viewpoint of improving the polishing rate and flatness, R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 represents a phenyl group, a cytidine group, a guanidino group, or an alkylguanidino group; X 1 represents a bond or an alkylene group having 1 to 4 carbon atoms, and n represents 0 or 1. In formula (I), in one or more embodiments, from the viewpoint of improving the polishing rate and flatness, R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 represents a phenyl group, and X 1 represents a bond, and n represents 0 or 1.

[0025] In the formula (II), R 4 and R 5 In terms of availability, salts of hydroxyl groups are preferred. X 2 From the viewpoint of improving the polishing rate and improving the flatness, is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, still more preferably an alkylene group having 1 to 8 carbon atoms, still more preferably an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 4 carbon atoms, still more preferably an alkylene group having 2 or 3 carbon atoms, and preferably an alkylene group having 2 carbon atoms (ethylene group). n1 and n2 are preferably 1 from the viewpoint of improving the polishing rate and flatness.

[0026] Examples of component B include creatinol phosphate or a salt thereof, O-phosphorylethanolamine or a salt thereof, phosphocholine sodium chloride hydrate or a salt thereof, alkylphosphonic acids or salts thereof such as butylphosphonic acid, phenylphosphonic acid or a salt thereof, cytidine 5-phosphate or a salt thereof, cytidine 5-diphosphocholine sodium, alkyl phosphate monoesters and salts thereof such as methyl acid phosphate and butyl acid phosphate, etc. From the viewpoint of improving the polishing rate and improving the flatness, component B is preferably phenylphosphonic acid or a salt thereof.

[0027] From the viewpoint of improving the removal rate and improving flatness, the content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.0075% by mass or more. From the same viewpoint, the content of component B in the polishing liquid composition of the present disclosure is preferably 0.01 mM or more, more preferably 0.05 mM or more, even more preferably 0.1 mM or more, and preferably 5 mM or less, more preferably 3 mM or less, and even more preferably 2 mM or less. The content of component B in the polishing liquid composition of the present disclosure is preferably 0.01 mM or more and 5 mM or less, more preferably 0.05 mM or more and 3 mM or less, and even more preferably 0.1 mM or more and 2 mM or less. When component B is a combination of two or more types, the content of component B refers to the total content thereof.

[0028] [Nitrogen-containing heteroaromatic compounds (component C)] The polishing composition of the present disclosure contains a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom has been substituted with a hydroxyl group (hereinafter, also simply referred to as "component C"). From the viewpoint of improving the polishing rate and improving flatness, component C is preferably at least one compound selected from N-oxide compounds containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom has been substituted with a hydroxyl group and salts thereof. Examples of the salt include alkali metal salts, alkaline earth metal salts, organic amine salts, and ammonium salts. Component C may be used alone or in combination of two or more types.

[0029] In one or more embodiments, the term "N-oxide compound" used herein refers to a compound having an N-oxide group (N→O group). The N-oxide compound may have one or more N→O groups, and from the viewpoint of availability, one N→O group is preferred.

[0030] In the present disclosure, at least one nitrogen atom contained in the nitrogen-containing heteroaromatic ring skeleton forms an N-oxide. In one or more embodiments, the nitrogen-containing heteroaromatic ring contained in Component C may be a monocyclic or bicyclic fused ring. In one or more embodiments, the number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in Component C may be 1 to 3, and from the viewpoints of improving the polishing rate and flatness, 1 or 2 is preferred, and 1 is more preferred. In one or more embodiments, the nitrogen-containing heteroaromatic ring skeleton contained in Component C may be at least one selected from a pyridine N-oxide skeleton, a quinoline N-oxide skeleton, and the like. In the present disclosure, the pyridine N-oxide skeleton refers to a structure in which a nitrogen atom contained in a pyridine ring forms an N-oxide. The quinoline N-oxide skeleton refers to a structure in which a nitrogen atom contained in a quinoline ring forms an N-oxide.

[0031] In one or more embodiments, Component C may be at least one selected from an N-oxide compound having a pyridine ring in which at least one hydrogen atom is substituted with a hydroxy group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom is substituted with a hydroxy group, and salts thereof. Among these, from the viewpoints of improving the polishing rate and improving flatness, Component B is preferably an N-oxide compound having a pyridine ring in which at least one hydrogen atom is substituted with a hydroxy group or a salt thereof.

[0032] Examples of component C include 2-hydroxypyridine N-oxide, 3-hydroxypyridine N-oxide, and 8-hydroxyquinoline N-oxide.

[0033] The content of component C in the polishing composition of the present disclosure is preferably 0.01 mM or more, more preferably 0.05 mM or more, and even more preferably 0.1 mM or more, from the viewpoints of improving the polishing rate and improving flatness. It has been found that component C also adsorbs to the silicon oxide film to be polished. If the content of component C is too high, polishing of the silicon oxide film at the convex portion (wiring portion) with a wide line width, which is relatively less susceptible to polishing load, becomes difficult to proceed, and line width dependency is thought to deteriorate. Therefore, from the viewpoint of reducing line width dependency, the content of component C in the polishing composition of the present disclosure is preferably 5 mM or less, more preferably 3 mM or less, even more preferably 0.8 mM or less, and even more preferably 2 mM or less. The content of component C in the polishing composition of the present disclosure is preferably 0.01 mM or more and 5 mM or less, more preferably 0.05 mM or more and 3 mM or less, and even more preferably 0.1 mM or more and 2 mM or less. When component C is a combination of two or more types, the content of component C refers to the total content of these components.

[0034] From the viewpoints of improving the polishing rate and improving flatness, the molar ratio C / B of the content of component C to the content of component B in the polishing liquid composition of the present disclosure is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, even more preferably 0.5 or more, and is preferably 100 or less, more preferably 20 or less, even more preferably 10 or less, even more preferably 5 or less, and even more preferably 4 or less. The molar ratio C / B in the polishing liquid composition of the present disclosure is preferably 0.01 or more and 100 or less, more preferably 0.05 or more and 20 or less, even more preferably 0.1 or more and 20 or less, even more preferably 0.5 or more and 20 or less, even more preferably 0.5 or more and 5 or less, and even more preferably 0.5 or more and 4 or less.

[0035] [Aqueous medium] Examples of the aqueous medium contained in the polishing liquid composition of the present disclosure include water such as distilled water, ion-exchanged water, pure water, and ultrapure water, or a mixed solvent of water and a solvent. Examples of the solvent include a water-miscible solvent (e.g., alcohol such as ethanol). When the aqueous medium is a mixed solvent of water and a solvent, the proportion of water in the total mixed medium is not particularly limited as long as the effects of the present disclosure are not impaired. From an economical viewpoint, the proportion of water is preferably 95% by mass or more, more preferably 98% by mass or more, and preferably less than 100% by mass. From the viewpoint of surface cleanliness of the substrate to be polished, the aqueous medium is preferably water, more preferably ion-exchanged water and ultrapure water, and even more preferably ultrapure water. The content of the aqueous medium in the polishing composition of the present disclosure can be the remainder excluding Component A, Component B, Component C, and any optional components described below that are blended as necessary.

[0036] [Optional ingredients] The polishing liquid composition of the present disclosure may further contain optional components such as pH adjusters, surfactants, thickeners, dispersants, rust inhibitors, preservatives, basic substances, polishing rate enhancers, silicon nitride film polishing suppressors, and polysilicon film polishing suppressors. When the polishing liquid composition of the present disclosure further contains optional components, the content of the optional components in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.0025% by mass or more, even more preferably 0.01% by mass or more, and preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, from the viewpoint of improving the polishing rate and improving flatness. The content of the optional components in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more to 1% by mass or less, more preferably 0.0025% by mass or more to 0.5% by mass or less, and even more preferably 0.01% by mass or more to 0.1% by mass or less.

[0037] In one or more embodiments, the polishing liquid composition of the present disclosure may not contain metal cations.

[0038] [Polishing liquid composition] The polishing composition of the present disclosure can be produced by a production method including a step of blending component A, component B, component C, an aqueous medium, and, if necessary, optional components by a known method. For example, the polishing composition of the present disclosure can be produced by blending a dispersion (slurry) containing component A and an aqueous medium, or a solution containing component B, component C, and an aqueous medium, and, if necessary, optional components. In the present disclosure, "blending" includes simultaneously or sequentially mixing component A, component B, component C, and the aqueous medium, and, if necessary, optional components. The order of mixing is not particularly limited. The blending can be carried out using a mixer such as a homomixer, homogenizer, ultrasonic disperser, or wet ball mill. The blending amount (addition amount) of each component in the production method of the polishing composition of the present disclosure can be the same as the content of each component in the polishing composition of the present disclosure described above.

[0039] An embodiment of the polishing liquid composition of the present disclosure may be a so-called one-component type in which all components are premixed and supplied to the market, or may be a so-called two-component type in which components are mixed at the time of use.

[0040] From the viewpoints of improving the removal rate and improving flatness, the pH of the polishing composition of the present disclosure is preferably 4 or more, more preferably 4.5 or more, and preferably 8 or less, more preferably 7 or less, and even more preferably 6.5 or less. From the same viewpoint, the pH of the polishing composition of the present disclosure is preferably 4 or more and 8 or less, more preferably 4 or more and 6.5 or less. In the present disclosure, the pH of the polishing composition is a value at 25°C, measured using a pH meter. Specifically, the pH of the polishing composition of the present disclosure can be measured by the method described in the Examples.

[0041] In the present disclosure, the "content of each component in the polishing composition" refers to the content of each component at the time when the polishing composition is first used for polishing. In one or more embodiments, the content of each component in the polishing composition of the present disclosure can be considered to be the blending amount (addition amount) of each component in the polishing composition of the present disclosure. The polishing composition of the present disclosure may be stored and supplied in a concentrated state to the extent that its stability is not impaired. This is preferable in that production and transportation costs can be reduced. If necessary, this concentrated liquid can be appropriately diluted with the aqueous medium described above and used in the polishing process. The dilution ratio is preferably 5 to 100 times.

[0042] [Polished film] Examples of films to be polished using the polishing composition of the present disclosure include silicon oxide films formed during the manufacturing process of semiconductor substrates. Therefore, the polishing composition of the present disclosure can be used in processes that require polishing of silicon oxide films. In one or more embodiments, the polishing composition of the present disclosure can be suitably used for polishing silicon oxide films in processes for forming element isolation structures on semiconductor substrates, for polishing silicon oxide films in processes for forming interlayer insulating films, for polishing silicon oxide films in processes for forming buried metal wiring, or for polishing silicon oxide films in processes for forming buried capacitors. In one or more other embodiments, the polishing composition of the present disclosure can be suitably used in the manufacture of three-dimensional semiconductor devices such as three-dimensional NAND flash memories.

[0043] [Polishing liquid kit] In one aspect, the present disclosure relates to a kit for preparing the polishing liquid composition of the present disclosure (hereinafter also referred to as the "polishing liquid kit of the present disclosure"). The polishing liquid kit of the present disclosure may be, for example, a polishing liquid kit (two-liquid polishing liquid composition) that contains an abrasive dispersion (first liquid) containing component A and an aqueous medium and an additive aqueous solution (second liquid) containing component B and component C in a mutually unmixed state, which are mixed at the time of use and diluted with an aqueous medium as needed. The aqueous medium contained in the abrasive dispersion (first liquid) may be the entire amount of the aqueous medium used to prepare the polishing liquid composition, or it may be only a portion of the amount. The additive aqueous solution (second liquid) may contain a portion of the aqueous medium used to prepare the polishing liquid composition. The abrasive dispersion (first liquid) and the additive aqueous solution (second liquid) may each contain the optional components described above, as needed. The abrasive dispersion (first liquid) and the additive aqueous solution (second liquid) may be mixed before being supplied to the surface to be polished, or they may be supplied separately and then mixed on the surface of the substrate to be polished. The polishing liquid kit of the present disclosure may provide a polishing liquid composition that can improve the removal rate of silicon oxide films.

[0044] [Method of manufacturing semiconductor substrate] In one aspect, the present disclosure relates to a method for manufacturing a semiconductor substrate (hereinafter also referred to as the "semiconductor substrate manufacturing method of the present disclosure"), which includes a step of polishing a film to be polished using the polishing liquid composition of the present disclosure (hereinafter also referred to as the "polishing step using the polishing liquid composition of the present disclosure"). The semiconductor substrate manufacturing method of the present disclosure relates to a method for manufacturing a semiconductor device, which includes, for example, a step of polishing the surface of a silicon oxide film opposite to the surface that contacts a silicon nitride film, for example, the uneven step surface of the silicon oxide film, using the polishing liquid composition of the present disclosure. The semiconductor device manufacturing method of the present disclosure enables high-speed polishing of a silicon oxide film, and therefore can achieve the effect of efficiently manufacturing semiconductor devices.

[0045] The uneven step surface of the silicon oxide film may be formed naturally in correspondence with the uneven steps of the underlying layer of the silicon oxide film when the silicon oxide film is formed by a method such as chemical vapor deposition, or may be obtained by forming an uneven pattern using a method such as lithography.

[0046] In a specific example of a method for manufacturing a semiconductor substrate according to the present disclosure, a silicon dioxide layer is grown on the surface of a silicon substrate by exposing the silicon substrate to oxygen in an oxidation furnace. A polishing stopper film, such as a silicon nitride (SiN) film or a polysilicon film, is then formed on the silicon dioxide layer by, for example, chemical vapor deposition (CVD). Next, a trench is formed using photolithography in a substrate including a silicon substrate and a polishing stopper film disposed on one main surface of the silicon substrate, e.g., a silicon dioxide (SiO) film, which serves as a polishing film to fill the trench, is then formed by, for example, CVD using silane gas and oxygen gas, to obtain a polished substrate in which the polishing stopper film is covered with the polishing film (silicon oxide film). By forming the silicon oxide film, the trench is filled with silicon oxide from the silicon oxide film, and the surface of the polishing stopper film opposite the surface facing the silicon substrate is covered with the silicon oxide film. The surface of the silicon oxide film thus formed opposite the surface facing the silicon substrate has steps formed corresponding to the unevenness of the underlying layer. The silicon oxide film is then polished by CMP until at least the surface opposite the surface facing the silicon substrate of the polishing stopper film is exposed, more preferably until the surface of the silicon oxide film and the surface of the polishing stopper film are flush with each other. The polishing composition of the present disclosure can be used in this polishing process by CMP. The width of the convex portions formed in the silicon oxide film corresponding to the unevenness of the underlying layer is, for example, 0.5 μm or more and 5000 μm or less, and the width of the concave portions is, for example, 0.5 μm or more and 5000 μm or less.

[0047] In polishing by the CMP method, the surface of the substrate to be polished is brought into contact with a polishing pad, and the polishing liquid composition of the present disclosure is supplied to the contact site while the substrate to be polished and the polishing pad are moved relative to each other, thereby planarizing the uneven portions of the surface of the substrate to be polished. In the method for manufacturing a semiconductor substrate according to the present disclosure, another insulating film may be formed between the silicon dioxide layer of the silicon substrate and the polishing stopper film, or another insulating film may be formed between the film to be polished (e.g., a silicon oxide film) and the polishing stopper film (e.g., a silicon nitride film).

[0048] In a polishing process using the polishing liquid composition of the present disclosure, the rotation speed of the polishing pad is, for example, 30 to 200 rpm / min, the rotation speed of the substrate to be polished is, for example, 30 to 200 rpm / min, and the polishing load set in the polishing apparatus equipped with the polishing pad is, for example, 20 to 500 gf / cm 2 The supply rate of the polishing composition can be set to, for example, 10 to 500 mL / min. or less.

[0049] In the polishing step using the polishing liquid composition of the present disclosure, conventionally known polishing pad materials can be used. Examples of polishing pad materials include organic polymer foams such as rigid polyurethane foams and non-foamed materials, with rigid polyurethane foams being preferred.

[0050] [Polishing method] In one aspect, the present disclosure relates to a polishing method (hereinafter also referred to as the polishing method of the present disclosure) that includes a step of polishing a film to be polished using the polishing composition of the present disclosure, wherein the film to be polished is a silicon oxide film formed during the manufacturing process of a semiconductor substrate. Use of the polishing method of the present disclosure can improve the polishing rate of the silicon oxide film, thereby achieving the effect of improving the productivity of semiconductor substrates with improved quality. The specific polishing method and conditions can be the same as those of the manufacturing method of semiconductor substrates of the present disclosure described above. [Example]

[0051] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples in any way.

[0052] 1. Preparation of Polishing Composition [Preparation of Polishing Compositions of Examples 1 to 14 and Comparative Examples 1 to 8] Polishing liquid compositions of Examples 1 to 14 and Comparative Examples 1 to 8 were obtained by mixing cerium oxide particles (component A) shown in Table 2, compounds (component B or non-component B) shown in Tables 1 and 2, a nitrogen-containing heteroaromatic compound (component C) shown in Table 2, and water. The amount (content) of each component added (mass % or mM, active ingredient) in the polishing liquid composition is as shown in Table 2, and the content of water is the remainder excluding component A and component B or non-component B and component C. pH adjustment was performed using ammonia or nitric acid.

[0053] The cerium oxide particles (component A) shown in Table 2 were as follows: Positively charged ceria (calcined and ground ceria, average primary particle diameter: 29 nm, BET specific surface area: 29 m 2 / g, surface potential=100mV)

[0054] The compounds (component B or non-component B) shown in Tables 1 and 2 were as follows. (Component B) B1: Phenylphosphonic Acid [Tokyo Chemical Industry Co., Ltd.] B2: Creatinol Phosphate [Tokyo Chemical Industry Co., Ltd.] B3: Phosphocholine Chloride Sodium Salt Hydrate (Tokyo Chemical Industry Co., Ltd.) B4: Butylphosphonic Acid [Tokyo Chemical Industry Co., Ltd.] B5: Cytidine 5'-Monophosphate [Tokyo Chemical Industry Co., Ltd.] B6: Cytidine 5'-Diphosphocholine Sodium Salt (Tokyo Chemical Industry Co., Ltd.) (Non-ingredient B) B7: Creatine Hydrate [Tokyo Chemical Industry Co., Ltd.] B8: 2-(Methacryloyloxy)ethyl 2-(Trimethylammonio)ethyl Phosphate (2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate) [Tokyo Chemical Industry Co., Ltd.] B9: Polyvinylpyrrolidone [Polyvinylpyrrolidone K30, manufactured by Tokyo Chemical Industry Co., Ltd.]

[0055] The nitrogen-containing heteroaromatic compounds (component C) shown in Table 2 were as follows: 2-Hydroxypyridine N-oxide [Tokyo Chemical Industry Co., Ltd.]

[0056] [Table 1]

[0057] 2.Measuring methods for various parameters [pH of polishing composition] The pH value of the polishing composition at 25°C was measured using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.) one minute after the electrode was immersed in the polishing composition. The results are shown in Table 2.

[0058] [Average primary particle size of cerium oxide particles] The average primary particle diameter (nm) of cerium oxide particles is calculated by the BET (nitrogen adsorption) method. 2 / g) and is calculated by the following formula: particle diameter (converted to spherical). In the following formula, the specific surface area S was determined by drying 10 g of a slurry of cerium oxide particles under reduced pressure at 110°C to remove moisture, crushing the resulting powder in an agate mortar, and measuring the powder using a flow-type automatic specific surface area measuring device, FlowSorb 2300 (manufactured by Shimadzu Corporation). Average primary particle diameter (nm)=820 / S

[0059] [Surface potential of cerium oxide] The surface potential (mV) of the cerium oxide particles was measured using a surface potential measurement device (Zeta Probe, manufactured by Kyowa Interface Science Co., Ltd.). Ultrapure water was used to adjust the cerium oxide concentration to 0.15%, and the solution was placed in the surface potential measurement device. The surface potential was measured under the conditions of a particle density of 7.13 g / ml and a particle dielectric constant of 7. The measurement was performed three times, and the average value was used as the measurement result.

[0060] 3. Evaluation of Polishing Compositions (Examples 1 to 14 and Comparative Examples 1 to 8) [Evaluation sample] A commercially available CMP characteristic evaluation wafer (Advantec's "P-TEOS CMP464 PT wafer," 200 mm in diameter) was prepared as an evaluation sample and cut into a 40 mm x 40 mm piece. This evaluation sample had a 2000 nm thick silicon oxide film disposed on a silicon substrate as the convex portions, and a similar 2000 nm thick silicon oxide film disposed on the concave portions. A linear concave-convex pattern was formed by etching so that the step between the convex portions and the concave portions was 800 nm. The silicon oxide film was formed from P-TEOS, and the measurement targets used were those with convex and concave line widths of 50 μm, 500 μm, and 4 mm, respectively.

[0061] [Polishing conditions] Polishing device: TriboLab CMP (manufactured by Bruker) Plate rotation speed: 100 rpm Head rotation speed: 107 rpm Polishing load: 99.3N Polishing liquid supply amount: 50mL / min Grinding time: 1 / 3 minute

[0062] [Polishing speed] Evaluation samples were polished under the above-mentioned polishing conditions using each of the polishing compositions of Examples 1 to 14 and Comparative Examples 1 to 8. After polishing, the evaluation samples were washed with ultrapure water and dried, and then subjected to measurement using an optical interference film thickness measuring device described below. Before and after polishing, the thickness of the silicon oxide film on the convex portions was measured using an optical interference film thickness measurement device ("VM-1230" manufactured by SCREEN Semiconductor Solutions). The polishing rate of the silicon oxide film on the convex portions was calculated using the following formula. The calculation results are shown in Table 2. Polishing speed of convex part (nm / min) = [Silicon oxide film thickness of the convex part before polishing (nm) - Silicon oxide film thickness of the convex part after polishing (nm)] / Polishing time (min)

[0063] [Line width dependency] The line width dependency was evaluated by calculating the difference (polishing rate difference a, b) between the polishing rate for a convex portion with a line width of 4 mm and the polishing rate for the same convex portion with a line width of 50 μm or 500 μm. The smaller the polishing rate difference, the lower the line width dependency was evaluated to be. The results are shown in Table 2. In Table 2, the polishing rate difference a (nm / min) is the absolute value of the difference between the polishing rate for a convex portion with a line width of 4 mm and the polishing rate for a convex portion with a line width of 50 μm. The polishing rate difference b (nm / min) is the absolute value of the difference between the polishing rate for a convex portion with a line width of 4 mm and the polishing rate for a convex portion with a line width of 500 μm.

[0064] [Stability over time] After preparing the ground ceria slurry using the above method, the zeta potential was measured using an electroacoustic high-concentration zeta potential meter (Agilent Technologies), and the slurry was placed in a 100 mL container and allowed to stand at room temperature. After one week, the zeta potential was measured again, and the stability of the slurry over time was evaluated according to the following evaluation criteria. The smaller the change in zeta potential before and after storage, the better the stability. <Evaluation criteria> A: The change in zeta potential before and after storage is 30% or less B: The change in zeta potential before and after storage is more than 30% and less than 50% C: The change in zeta potential before and after storage is more than 50%.

[0065] [Table 2]

[0066] As shown in Table 2, it was found that the polishing compositions of Examples 1 to 14 were able to achieve both an improved removal rate and a reduced line width dependency, compared to the polishing compositions of Comparative Examples 1 to 4 and 6 to 8. Furthermore, it was found that the polishing compositions of Examples 1 to 14 were excellent in stability over time. The polishing composition of Comparative Example 5 could not be evaluated because sediment was generated. [Industrial Applicability]

[0067] The polishing composition according to the present disclosure is useful in a method for manufacturing a semiconductor device for high density or high integration.

Claims

1. The composition contains cerium oxide particles (component A), a compound represented by the following formula (I) or (II) (component B), a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom is substituted with a hydroxyl group (component C), and an aqueous medium, The polishing composition for silicon oxide films, wherein the component C is at least one compound selected from N-oxide compounds and salts thereof, each of which has a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group. 【Chemistry 1】 In the formula (I), R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 represents a phenyl group, a cytidine group, a guanidino group, or an alkylguanidino group; X 1 represents a bond or an alkylene group having 1 to 4 carbon atoms; n represents 0 or 1. In the formula (II), R 4 and R 5 are the same or different and represent a hydroxyl group or a salt thereof; Z 1 is H or -N + (CH 3 ) 3 indicates Z 2 represents a cytidine group, and X 2 represents a bond or an alkylene group having 1 to 12 carbon atoms; n1 and n2 may be the same or different and represent 0 or 1;

2. In the formula (I), R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 represents a phenyl group, and X 1 The polishing composition according to claim 1 , wherein represents a bond, and n represents 0 or 1.

3. 3. The polishing composition according to claim 1, wherein the content of Component B is 0.01 mM or more and 5 mM or less.

4. 4. The polishing composition according to claim 1, wherein the content of Component C is 0.01 mM or more and 5 mM or less.

5. 5. The polishing composition according to claim 1, wherein the molar ratio C / B of the content of component C to the content of component B is 0.5 or more and 20 or less.

6. The polishing composition according to claim 1 , wherein the content of Component A is 0.001% by mass or more and 6% by mass or less.

7. 7. The polishing composition according to claim 1, wherein the pH of the polishing composition at 25°C is 4 or more and 8 or less.

8. 8. The polishing composition according to claim 1, wherein the pH of the polishing composition at 25°C is 4 or more and 6.5 or less.

9. A method for producing a semiconductor substrate, comprising a step of polishing a film to be polished with the polishing composition according to claim 1 .

10. 9. A polishing method comprising the step of polishing a film to be polished with the polishing composition according to claim 1, wherein the film to be polished is a silicon oxide film formed in the process of manufacturing a semiconductor substrate.

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