Composition of polishing solution

Abstract

To provide a composition of a polishing solution having a stable polishing performance in an embodiment.SOLUTION: The present disclosure relates to a composition of a polishing solution in an embodiment including: a cerium-containing particle (component A); a chemical compound (component B) which can be coordinated in a cerium ion; and water, or relates to a concentrated material of the composition of a polishing solution. The amount of cerium ions in the composition of a polishing solution or the concentrated material of the composition of a polishing solution is 125 ppm at most.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a polishing composition or a concentrate thereof, a method for producing a semiconductor substrate using the same, and a method for polishing a substrate. [Background technology]

[0002] Chemical mechanical polishing (CMP) is a technique in which the surface of the substrate to be polished is brought into contact with a polishing pad, and a polishing liquid is supplied to the contact point while the substrate and polishing pad are moved relative to each other, thereby chemically reacting with and mechanically removing and planarizing the uneven surface of the substrate.

[0003] Currently, CMP technology is essential in the manufacturing process of semiconductor devices for flattening interlayer insulating films, forming shallow trench isolation structures, forming plugs and buried metal wiring, etc. In recent years, semiconductor devices have become increasingly multi-layered and highly precise, and there is a demand for further improvements in the yield and throughput of semiconductor devices. Accordingly, there is a demand for scratch-free and faster polishing in the CMP process.

[0004] For example, Patent Document 1 proposes a polishing liquid that contains an abrasive grain, a compound having an aromatic heterocycle, and water, in which the abrasive grain contains a hydroxide of a tetravalent metal element (e.g., tetravalent cerium), the aromatic heterocycle has an intracyclic nitrogen atom that is not bonded to a hydrogen atom, and the charge of the intracyclic nitrogen atom obtained by the Mers-Kollman method is −0.50 or less. Patent Document 2 proposes a polishing composition containing water, cerium oxide fine particles, and a chelating agent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-149548 A [Patent Document 2] WO01 / 080296 issue Summary of the Invention [Problem to be solved by the invention]

[0006] As a method for producing cerium-containing particles (abrasive grains) such as cerium oxide particles, a wet grinding method and a wet disintegration method are known. However, cerium ions may be eluted from the cerium-containing particles during wet grinding or wet disintegration. If cerium ions derived from the abrasive grains are mixed into the polishing liquid composition, the cerium ions derived from the abrasive grains react with additives in the polishing liquid composition during storage of the polishing liquid composition to form a complex, which leads to problems such as the generation of precipitates and the reduction in the amount of effective additives, resulting in fluctuations in polishing performance (e.g., fluctuations in polishing rate). In particular, when a concentrate of the polishing liquid composition is produced and then diluted for use, the generation of precipitates at the concentrate stage becomes a problem. Therefore, the polishing liquid composition or its concentrate is required to have stable polishing performance.

[0007] Therefore, the present disclosure provides a polishing composition or a concentrate thereof having stable polishing performance, a method for producing a semiconductor substrate using the same, and a method for polishing a substrate. [Means for solving the problem]

[0008] In one aspect, the present disclosure relates to a polishing liquid composition or a concentrate thereof, which contains cerium-containing particles (component A), a compound capable of coordinating with cerium ions (component B), and water, wherein the amount of cerium ions in the polishing liquid composition or the concentrate thereof is 125 ppm or less.

[0009] In one aspect, the present disclosure relates to a method for producing the polishing liquid composition of the present disclosure, the method including a step of diluting a concentrate of a polishing liquid composition that contains cerium-containing particles (component A), a compound capable of coordinating with cerium ions (component B), and water, and has a cerium ion amount of 125 ppm or less.

[0010] In one aspect, the present disclosure relates to a polishing method, comprising a step of polishing a film to be polished using the polishing liquid composition of the present disclosure or a polishing liquid composition produced by a method for producing a polishing liquid composition of the present disclosure, wherein the film to be polished is a silicon oxide film formed in the process of producing a semiconductor substrate.

[0011] In one aspect, the present disclosure relates to a method for producing a semiconductor substrate, the method including a step of polishing a film to be polished using the polishing liquid composition according to any one of the above-described embodiments or a method for producing a polishing liquid composition according to any one of the above-described embodiments. Effect of the Invention

[0012] According to one aspect of the present disclosure, a polishing composition having stable polishing performance can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In one aspect, the present disclosure is based on the finding that by combining a specific cerium-containing particle with a compound capable of coordinating to a cerium ion, it is possible to suppress the generation of precipitates due to storage or to suppress a decrease in the polishing rate, thereby maintaining stable polishing performance.

[0014] That is, in one aspect, the present disclosure relates to a polishing liquid composition or a concentrate thereof, which contains cerium-containing particles (component A), a compound capable of coordinating with cerium ions (component B), and water, and in which the amount of cerium ions in the polishing liquid composition or the concentrate thereof is 125 ppm or less (hereinafter also referred to as the "polishing liquid composition of the present disclosure") or a concentrate thereof.

[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. The cerium-containing particles (component A) are subjected to wet grinding for the purpose of dispersion and particle size adjustment. Wet grinding is a method of grinding or disintegrating particles in a state (slurry) mixed with a solvent (e.g., water), and dispersion proceeds by collision with bead media and collision between particles. At this time, frictional heat is generated on the particle surface due to collision, and the cerium-containing particles are dissolved by the heat, and cerium ions are mixed into the slurry (cerium-containing particle dispersion). When a polishing liquid composition or a concentrate thereof containing a compound (component B) capable of coordinating with cerium ions and water is prepared using the cerium-containing particle dispersion obtained in this way, the cerium ions derived from the cerium-containing particles and component B gradually react during storage of the polishing liquid composition to form a complex. This is thought to cause the generation of precipitates and the reduction in the amount of effective additives, resulting in fluctuations in polishing performance. In the present disclosure, it is believed that by keeping the amount of cerium ions at or below a predetermined value, it is possible to suppress the occurrence of precipitates during storage of the polishing composition or a concentrate thereof, and fluctuations in polishing performance due to a reduction in the amount of effective additives. However, the present disclosure need not be construed as being limited to these mechanisms.

[0016] [Amount of cerium ions] The amount of cerium ions in the polishing composition or concentrate thereof of the present disclosure is 125 ppm or less, preferably 100 ppm or less, more preferably 75 ppm or less, from the viewpoint of suppressing the generation of precipitates and improving the stability of polishing performance. The amount of cerium ions can be adjusted by adjusting the rotation speed, temperature, etc. during wet grinding of the cerium-containing particles. The amount of cerium ions can be measured by the method described in the Examples.

[0017] The amount of cerium ions per 1 g of cerium-containing particles (component A) in the polishing liquid composition or concentrate thereof of the present disclosure is preferably 25 ppm or less, more preferably 20 ppm or less, even more preferably 15 ppm or less, and even more preferably 10 ppm or less, from the viewpoint of suppressing the generation of precipitates and improving the stability of polishing performance. In one or more embodiments, the amount of cerium ions per 1 g of cerium-containing particles is the amount of dissolved cerium ions per 1 g of cerium-containing particles in the polishing liquid composition or concentrate thereof. The amount of cerium ions per 1 g of cerium-containing particles can be measured by the method described in the Examples.

[0018] [Cerium-containing particles (component A)] The polishing liquid composition or concentrate thereof of the present disclosure contains cerium-containing particles (hereinafter, also simply referred to as "Component A") as polishing abrasive grains. Component A is a particle containing cerium, and examples thereof include cerium oxide (ceria) particles, cerium hydroxide particles, and cerium oxide-coated particles (e.g., ceria-coated silica). Component A may be one type or a combination of two or more types.

[0019] 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, by the method described in Examples 1 to 4 of JP-A-2010-505735. Examples of the amorphous ceria include pulverized or crushed ceria. One embodiment of the pulverized or crushed ceria includes sintered pulverized ceria obtained by sintering, pulverizing or crushing a cerium compound such as cerium carbonate or cerium nitrate. Other embodiments of the pulverized or crushed ceria include single crystal pulverized ceria or crushed ceria obtained by wet pulverizing or wet crushing ceria particles in the presence of an inorganic acid or an organic acid. Examples of the inorganic acid used during wet pulverization or wet crushing include nitric acid, and examples of the organic acid include organic acids having a carboxyl group, specifically at least one selected from acetic acid, propionic acid, picolinic acid, glutamic acid, aspartic acid, aminobenzoic acid and p-hydroxybenzoic acid. Examples of the wet pulverization method include wet pulverization using a planetary bead mill or the like. Examples of the wet crushing method include wet crushing using a wet bead mill, a wet high-pressure jet mill, or the like. 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, for example, Examples 1 to 14 of JP2015-63451A or Examples 1 to 4 of JP2013-119131A. The composite particles can be obtained, for example, by depositing ceria on silica particles.

[0020] From the viewpoint of polishing performance stability, Component A is preferably in the form of particles pulverized or crushed by a wet method, and more preferably in the form of particles pulverized or crushed by a wet high-pressure jet mill.

[0021] Examples of the shape of Component A include a substantially spherical shape, a polyhedral shape, and a raspberry shape.

[0022] From the viewpoint of improving the polishing rate, the particle diameter D50 of component A in terms of weight conversion by centrifugal sedimentation method is preferably 50 nm or more, more preferably 60 nm or more, and even more preferably 70 nm or more, and from the viewpoint of suppressing scratch generation, it is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 120 nm or less. More specifically, the particle diameter D50 of component A by centrifugal sedimentation method is preferably 50 nm or more and 200 nm or less, more preferably 60 nm or more and 150 nm or less, and even more preferably 70 nm or more and 120 nm or less.

[0023] In the present disclosure, D50 refers to the particle size at which the cumulative frequency from the small diameter side is 50% in the particle size distribution in weight conversion obtained by centrifugal sedimentation. In the present disclosure, the centrifugal sedimentation is, in one or more embodiments, a method of classifying and detecting particles by size based on the difference in sedimentation velocity (disk centrifugal sedimentation light transmission method). The particle size distribution by centrifugal sedimentation can be measured, for example, using a disk centrifugal particle size distribution measuring device (CPS Disc Centrifuge). In the following description, the particle size distribution by centrifugal sedimentation is sometimes referred to as "particle size distribution by CPS measurement". Specifically, it can be calculated by the measurement method described in the examples.

[0024] Examples of the method for adjusting the particle size distribution of component A by centrifugal sedimentation include a method for adjusting the particle growth time, reaction temperature, particle concentration, etc. during the growth process of the cerium-containing particles. Other embodiments of the method for adjusting the particle size distribution of component A by centrifugal sedimentation include a method for providing a desired particle size distribution by adding new core particles during the particle growth process in the production stage, and a method for providing a desired particle size distribution by mixing two or more types of particles having different particle size distributions.

[0025] The content of component A in the polishing liquid composition of the present disclosure is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.25% by mass or more from the viewpoint of improving the polishing rate and flatness of the entire surface of the substrate, and is preferably 5.0% by mass or less, more preferably 2.5% by mass or less, and even more preferably 1.0% by mass or less from the viewpoint of suppressing the occurrence of polishing scratches. More specifically, the content of component A in the polishing liquid composition of the present disclosure is preferably 0.05% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 2.5% by mass or less, and even more preferably 0.25% by mass or more and 1.0% by mass or less. When component A is a combination of two or more kinds, the content of component A refers to the total content thereof.

[0026] [Compound capable of coordinating with cerium ions (component B)] The compound capable of coordinating with cerium ions contained in the polishing composition or concentrate thereof according to the present disclosure (hereinafter, also simply referred to as "component B") may be, for example, an aromatic compound, a hydrocarbon compound, etc., from the viewpoint of improving the polishing rate. The aromatic compound may be an aromatic hydrocarbon or a heteroaromatic compound. The aromatic ring contained in the aromatic compound may be a single ring or a condensed ring of two or more rings. Examples of the hydrocarbon compound include a saturated hydrocarbon compound, an unsaturated hydrocarbon compound, and an alicyclic hydrocarbon compound. Component B may be one type or a combination of two or more types.

[0027] From the viewpoint of improving the polishing rate, Component B preferably has at least one functional group selected from a carboxyl group, a phosphoric acid group, a phosphorous acid group, a phosphinic acid group, and a hydroxyl group, and more preferably has at least one functional group selected from a phosphinic acid group and a hydroxyl group.

[0028] From the viewpoint of improving the polishing rate, component B may be at least one selected from a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom of a nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group (hereinafter also referred to as "component B1") and an aromatic compound having a phosphinic acid group (hereinafter also referred to as "component B2").

[0029] (Component B1: Nitrogen-containing heteroaromatic compounds) From the viewpoint of improving the polishing rate, the nitrogen-containing heteroaromatic compound (component B1) in which at least one hydrogen atom of the nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group 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 is 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. In the present disclosure, in one or more embodiments, an N-oxide compound 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, the number of N→O groups is preferably one. In the present disclosure, the term "nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group" refers to a structure in which at least one hydrogen atom of a nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group. In the present disclosure, at least one nitrogen atom contained in the nitrogen-containing heteroaromatic ring skeleton of component B1 forms an N-oxide. In one or more embodiments, the nitrogen-containing heteroaromatic ring contained in component B1 may be a monocyclic or bicyclic condensed ring. In one or more embodiments, the number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in component B1 may be 1 to 3, and from the viewpoint of improving the polishing rate, 1 or 2 is preferable, and 1 is more preferable. In one or more embodiments, the nitrogen-containing heteroaromatic ring skeleton contained in component B1 may be at least one selected from a pyridine N-oxide skeleton, a quinoline N-oxide skeleton, etc. 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. In one or more embodiments, component B1 may be at least one selected from an N-oxide compound having a pyridine ring in which at least one hydrogen atom of the pyridine ring is substituted with a hydroxy group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom of the quinoline ring is substituted with a hydroxy group, and salts thereof. Among these, from the viewpoint of improving the polishing rate, component B1 is preferably an N-oxide compound having a pyridine ring in which at least one hydrogen atom of the pyridine ring is substituted with a hydroxy group or a salt thereof. Component B1 may, for example, be 2-hydroxypyridine N-oxide or a salt thereof.

[0030] (Component B2: Aromatic compound having a phosphinic acid group) The aromatic ring compound (component B2) having a phosphinic acid group (-PH(=O)OH) includes arylphosphinic acid, alkylarylphosphinic acid, etc., and from the viewpoint of solubility, arylphosphinic acid is preferred. The arylphosphinic acid includes, for example, phenylphosphinic acid or its salt. The above salt includes alkali metal salt, alkaline earth metal salt, organic amine salt, ammonium salt, etc.

[0031] From the viewpoint of improving the polishing rate, Component B is preferably at least one selected from an N-oxide compound having a pyridine ring in which at least one hydrogen atom of the pyridine ring is substituted with a hydroxy group or a salt thereof, and an arylphosphinic acid or a salt thereof, and more preferably at least one selected from 2-hydroxypyridine N-oxide, phenylphosphinic acid, and a salt thereof.

[0032] The content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.0025% by mass or more, and even more preferably 0.005% by mass or more from the viewpoint of suppressing the variation in the polishing rate, and is preferably 1.0% 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 dispersion stability of component A. More specifically, the content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 1.0% by mass or less, more preferably 0.0025% by mass or more and 0.5% by mass or less, and even more preferably 0.005% by mass or more and 0.1% by mass or less. When component B is a combination of two or more kinds, the content of component B refers to the total content thereof.

[0033] From the viewpoint of improving the polishing rate, the mass ratio A / B of component A to component B (content of component A / content of component B) in the polishing liquid composition or concentrate thereof according to the present disclosure is preferably 1 or more, more preferably 2.5 or more, even more preferably 5 or more, and is preferably 500 or less, more preferably 250 or less, and even more preferably 150 or less. More specifically, the mass ratio A / B in the polishing liquid composition or concentrate thereof according to the present disclosure is preferably 1 or more and 500 or less, more preferably 2.5 or more and 250 or less, and even more preferably 5 or more and 150 or less.

[0034] [water] The water contained in the polishing liquid composition of the present disclosure or a concentrate thereof may be distilled water, ion-exchanged water, pure water, ultrapure water, etc. The content of water in the polishing liquid composition of the present disclosure may be the remainder excluding component A, component B, and any optional components described below that are blended as necessary.

[0035] [Other ingredients] The polishing composition or concentrate thereof of the present disclosure may further contain other components within the range in which the effects of the present disclosure are not impaired. Examples of other components include pH adjusters, surfactants, thickeners, dispersants, rust inhibitors, preservatives, basic substances, polishing speed enhancers, etc.

[0036] [Method of producing the polishing composition or concentrate thereof] In one or more embodiments, the polishing liquid composition or concentrate thereof of the present disclosure is prepared by blending at least component A, component B, and water. The polishing liquid composition or concentrate thereof of the present disclosure can be prepared, for example, by blending a cerium-containing particle dispersion (slurry) containing component A and water, component B, and the above-mentioned optional components (other components) as required by a known method. Thus, in one aspect, the present disclosure relates to a method for producing a polishing liquid composition or concentrate thereof of the present disclosure, which includes a step of preparing a cerium-containing particle dispersion (slurry) containing component A and water (hereinafter, also referred to as a "method for producing a polishing liquid composition or concentrate thereof of the present disclosure"). In one or more embodiments, the method for producing a polishing liquid composition or concentrate thereof of the present disclosure includes a step of blending a cerium-containing particle dispersion (slurry) containing component A and water, component B, and the above-mentioned optional components (other components) as required by a known method. When component A is a combination of multiple types of cerium-containing particles, component A can be obtained by blending multiple types of cerium-containing particles, respectively. When component B is a combination of multiple types of compounds, component B can be obtained by blending each of the multiple types of compounds. In the present disclosure, "blending" includes mixing component A, component B, water, and, if necessary, the above-mentioned optional components (other components) simultaneously or in sequence. The order of mixing is not particularly limited. The blending can be performed using a mixer such as a homomixer, homogenizer, ultrasonic disperser, and wet ball mill. The blending amount of each component in the method for producing the polishing liquid composition or concentrate thereof of the present disclosure can be the same as the content of each component in the polishing liquid composition or concentrate thereof of the present disclosure described above or below.

[0037] The amount of cerium ions per 1 g of cerium-containing particles (component A) in the cerium-containing particle dispersion (slurry) used for producing the polishing composition or concentrate thereof of the present disclosure is preferably 25 ppm or less, more preferably 20 ppm or less, even more preferably 15 ppm or less, and even more preferably 10 ppm or less, from the viewpoint of suppressing the generation of precipitates and improving the stability of polishing performance. In the present disclosure, the amount of cerium ions can be measured using high-frequency inductively coupled plasma emission spectrometry, specifically, it can be measured by the method described in the Examples.

[0038] The embodiment of the polishing liquid composition of the present disclosure may be a so-called one-liquid type in which all components are supplied to the market in a pre-mixed state, or a so-called two-liquid type in which the components are mixed at the time of use. An example of a two-liquid type polishing liquid composition is one that is composed of a first liquid containing component A and a second liquid containing component B, and the first liquid and the second liquid are mixed at the time of use. The first liquid and the second liquid may be mixed before being supplied to the surface of the object to be polished, or they may be supplied separately and mixed on the surface of the substrate to be polished. The first liquid and the second liquid may each contain the above-mentioned optional components as necessary.

[0039] The pH of the polishing liquid composition of the present disclosure is preferably 1.5 or more, more preferably 3 or more, and even more preferably 3.5 or more, from the viewpoint of improving the polishing rate, and is preferably 10 or less, more preferably 8.5 or less, and even more preferably 7 or less, from the viewpoint of improving the dispersion stability of component A. More specifically, the pH of the polishing liquid composition of the present disclosure is preferably 1.5 or more and 10 or less, more preferably 3 or more and 8.5 or less, and even more preferably 3.5 or more and 7 or less. In the present disclosure, the pH of the polishing liquid composition is a value at 25° C., and can be measured using a pH meter, specifically, can be measured by the method described in the Examples.

[0040] In the present disclosure, "the content of each component in the polishing liquid composition" refers to the content of each component at the time of polishing, that is, at the time when the polishing liquid composition starts to be used for polishing.

[0041] [Polishing composition concentrate] 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. In this case, it is preferable in that the manufacturing and transportation costs can be reduced. The concentrated product of the polishing composition of the present disclosure can be used in the polishing process by diluting it appropriately with water as necessary. The concentration ratio is preferably 5 to 100 times on a volume basis. In one or more embodiments, the polishing liquid composition concentrate of the present disclosure is a polishing liquid composition concentrate that contains component A, component B, and water and has a cerium ion amount of 125 ppm or less, and can be used by diluting with water so that the content of each component at the time of use becomes the above-mentioned content (i.e., the content at the time of use). In one or more embodiments, the present disclosure relates to a method for producing a polishing liquid composition, the method including a step of diluting a concentrate of the polishing liquid composition of the present disclosure. In one or more embodiments, the polishing liquid composition of the present disclosure may use a dilution of the concentrate of the polishing liquid composition of the present disclosure. In one or a plurality of embodiments, the present disclosure relates to a method for producing a polishing liquid composition, the method including a step of diluting a concentrate of a polishing liquid composition that contains Component A, Component B, and water and has a cerium ion amount of 125 ppm or less. When the polishing liquid composition of the present disclosure is a concentrate, the content of component A in the concentrate of the polishing liquid composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2.5% by mass or more from the viewpoint of transportation costs, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less from the viewpoint of product stability. More specifically, the content of component A in the concentrate of the polishing liquid composition of the present disclosure is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2.5% by mass or more and 10% by mass or less. The content of component B in the concentrate of the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.05% by mass or more from the viewpoint of improving the polishing rate, and is preferably 1% by mass or less, more preferably 0.75% by mass or less, and even more preferably 0.5% by mass or less from the viewpoint of the solubility of component B. More specifically, the content of component B in the concentrate of the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.01% by mass or more and 0.75% by mass or less, and even more preferably 0.05% by mass or more and 0.5% by mass or less. The pH of the concentrate of the polishing liquid composition of the present disclosure is preferably 1.5 or more, more preferably 3 or more, and even more preferably 3.5 or more, from the viewpoint of improving the polishing rate, and is preferably 10 or less, more preferably 8.5 or less, and even more preferably 7 or less, from the viewpoint of improving the dispersion stability of component A. More specifically, the pH of the concentrate of the polishing liquid composition of the present disclosure is preferably 1.5 or more and 10 or less, more preferably 3 or more and 8.5 or less, and even more preferably 3.5 or more and 7 or less. In the present disclosure, the pH of the concentrate of the polishing liquid composition is a value at 25° C., and can be measured using a pH meter, specifically, can be measured by the method described in the Examples.

[0042] [Polished film] An example of a film to be polished using the polishing composition of the present disclosure is a silicon oxide film formed in the manufacturing process of a semiconductor substrate. Therefore, in one or more embodiments, the polishing composition of the present disclosure is a polishing composition for silicon oxide films, and can be used in a process requiring polishing of a silicon oxide film. In one or more embodiments, the polishing composition of the present disclosure can be suitably used for polishing a silicon oxide film carried out in a step of forming an element isolation structure of a semiconductor substrate, polishing a silicon oxide film carried out in a step of forming an interlayer insulating film, polishing a silicon oxide film carried out in a step of forming embedded metal wiring, or polishing a silicon oxide film carried out in a step of forming an embedded capacitor. In one or more other embodiments, the polishing composition of the present disclosure can be suitably used for manufacturing a three-dimensional semiconductor device such as a three-dimensional NAND flash memory.

[0043] [Polishing liquid kit] In another aspect, the present disclosure relates to a kit for producing 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 type polishing liquid composition) containing a cerium-containing particle dispersion (slurry) containing component A and water, and an additive aqueous solution containing component B in a mutually unmixed state. The cerium-containing particle dispersion and the additive aqueous solution are mixed at the time of use, and diluted with water as necessary. The water contained in the cerium-containing particle dispersion may be the entire amount of water used in preparing the polishing liquid composition, or may be a part of the amount. The additive aqueous solution may contain a part of the water used in preparing the polishing liquid composition. The cerium-containing particle dispersion and the additive aqueous solution may each contain the above-mentioned optional components (other components) as necessary. According to the polishing liquid kit of the present disclosure, a polishing liquid composition having stable polishing performance can be obtained.

[0044] [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), which includes a step of polishing a film to be polished using the polishing liquid composition of the present disclosure or a polishing liquid composition manufactured by the manufacturing method of the polishing liquid composition of the present disclosure, and the film to be polished is a silicon oxide film formed in the manufacturing process of a semiconductor substrate. Examples of the film to be polished include the film to be polished in the polishing liquid composition of the present disclosure described above. By using the polishing method of the present disclosure, the film to be polished can be polished using a polishing liquid composition having stable polishing performance, so that the effect of improving the productivity of semiconductor substrates with improved quality can be achieved. The polishing method and conditions in the polishing method of the present disclosure can be the same as those in the manufacturing method of a semiconductor substrate of the present disclosure described below.

[0045] [Method of manufacturing semiconductor substrate] In one aspect, the present disclosure relates to a method for producing a semiconductor substrate (hereinafter also referred to as "the method for producing a semiconductor substrate of the present disclosure"), which includes a step of polishing a film to be polished using the polishing liquid composition of the present disclosure or a polishing liquid composition produced by the method for producing a 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 method for producing a semiconductor substrate of the present disclosure relates to a method for producing a semiconductor device, which includes a step of polishing, for example, a surface of a silicon oxide film opposite to a surface in contact with a silicon nitride film, for example, an uneven step surface of a silicon oxide film, using the polishing liquid composition of the present disclosure. According to the method for producing a semiconductor device of the present disclosure, a film to be polished can be polished using a polishing liquid composition having stable polishing performance, so that an effect of efficiently producing a semiconductor device can be achieved.

[0046] The uneven step surface of the silicon oxide film may be one that is naturally formed 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 one that is obtained by forming an uneven pattern using a lithography method or the like.

[0047] In a specific example of the method for manufacturing a semiconductor substrate according to the present disclosure, a silicon substrate is first exposed to oxygen in an oxidation furnace to grow a silicon dioxide layer on the surface of the substrate, and then a silicon nitride (Si 3 N 4 A polishing stopper film such as a silicon dioxide film or a polysilicon film is formed by, for example, a CVD method (chemical vapor deposition method). Next, a trench is formed by photolithography in a substrate including a silicon substrate and a polishing stopper film disposed on one main surface side of the silicon substrate, for example, a substrate in which a polishing stopper film is formed on a silicon dioxide layer of a silicon substrate. Next, a silicon dioxide (SiO 2) film is formed, and a substrate to be polished in which the polishing stopper film is covered with the polishing film (silicon oxide film) is obtained. By forming the silicon oxide film, the trench is filled with silicon oxide of the silicon oxide film, and the surface of the polishing stopper film opposite to the surface on the silicon substrate side is covered with the silicon oxide film. The surface opposite to the surface on the silicon substrate side of the silicon oxide film thus formed has a step formed corresponding to the unevenness of the lower layer. Next, the silicon oxide film is polished by the CMP method until at least the surface opposite to the surface on the silicon substrate side of the polishing stopper film is exposed, and more preferably, the silicon oxide film is polished until the surface of the silicon oxide film and the surface of the polishing stopper film are flush with each other. The polishing liquid composition of the present disclosure can be used in the step of performing polishing by this CMP method. The width of the convex portion formed corresponding to the unevenness of the lower layer of the silicon oxide film is, for example, 0.5 μm to 5000 μm, and the width of the concave portion is, for example, 0.5 μm to 5000 μm.

[0048] In polishing by CMP, 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 flattening the uneven portions of the surface of the substrate to be polished. In the semiconductor substrate manufacturing method of 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).

[0049] In the polishing step, 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. When the polishing composition is a two-liquid type polishing composition, the polishing rate of the film to be polished can be adjusted by adjusting the supply rates (or supply amounts) of the first liquid and the second liquid.

[0050] In the polishing step, the polishing rate of the film to be polished (silicon oxide film) is preferably 50 nm / min or more, more preferably 80 nm / min or more, and even more preferably 90 nm / min or more, from the viewpoint of improving productivity. EXAMPLES

[0051] Hereinafter, the present disclosure will be described with reference to examples, but the present disclosure is not limited thereto.

[0052] 1.Measuring methods for each parameter [pH of the polishing composition or its concentrate] The pH value of the polishing composition or its concentrate at 25°C is measured using a pH meter (manufactured by Toa Denpa Kogyo Co., Ltd., "HM-30G") and is the value measured one minute after the pH meter electrode was immersed in the polishing composition or its concentrate.

[0053] [Method of measuring D50 by centrifugal sedimentation method (CPS measurement) for cerium-containing particles] The cerium-containing particles were diluted with ion-exchanged water to prepare a dispersion containing 0.5% by mass of cerium-containing particles, and the particle size distribution was measured by centrifugal sedimentation using the following measuring device. The particle size at which the cumulative frequency from the small diameter side in the particle size distribution in weight conversion obtained by centrifugal sedimentation was 50% was defined as the average particle size. <Measurement conditions> Measurement range: 0.02~3μm Particle extinction coefficient: 0.1 Particle shape factor: 1.2 or 1.0 Revolution speed: 17,000 rpm Measurement temperature: 25℃

[0054] [Cerium ion concentration] 20 g of each cerium-containing particle sample (cerium-containing particle dispersion shown in Table 1) was centrifuged at 25,000 rpm for 30 minutes using a high-speed centrifuge (manufactured by Beckman Coulter, Inc.), and the supernatant was separated. The supernatant was then diluted 200 times with ultrapure water and measured under the following conditions using a multi-type ICP light-emitting device Afilent 5110 ICP-OES (manufactured by Agilent Technology, Inc.). The cerium ion concentration in Table 1 was determined by multiplying the cerium ion concentration of the actual measurement value by 50 times (only A-3 was multiplied by 100 times). The cerium ion concentration shown in Table 1 is the dissolved cerium ion concentration when the cerium-containing particle concentration is diluted to 5 mass%, and can be regarded as the amount of cerium ions in the concentrate of the polishing liquid composition shown in Table 2. <Measurement conditions> Measured element: Ce (418.659nm) Ce calibration standard solution concentrations: 0.2, 0.5, 1.0, 5.0, 10.0 ppm

[0055] [Amount of cerium ions per gram of cerium-containing particles] The amount of cerium ions per 1 g of cerium-containing particles was calculated by dividing the cerium ion concentration obtained above by the mass of the cerium-containing particles in the polishing composition. The amount of cerium ions per 1 g of cerium-containing particles shown in Table 1 can be regarded as the amount of cerium ions per 1 g of cerium-containing particles in the concentrate of the polishing composition shown in Table 2.

[0056] 2. Preparation of cerium-containing particle dispersions A-1 to A-7 Production examples of the cerium-containing particle dispersions A-1 to A-7 shown in Table 1 are shown below. [Production Example of Cerium-Containing Particle Dispersion A-1] 200 g of high-purity cerium oxide powder obtained using cerium nitrate as a starting material, 20 g of acetic acid, and 780 g of ultrapure water were mixed and dispersed under the following conditions using a wet bead mill (Ashizawa Finetech, Labostar Mini) to obtain cerium-containing particle dispersion A-1. <Crushing conditions> Beads: Zirconia (0.1um) Rotation speed: 8 rpm Processing time: 5 minutes Chiller temperature: 20℃ [Production Example of Cerium-Containing Particle Dispersion A-2] A cerium-containing particle dispersion A-2 was obtained by carrying out the same treatment as for the cerium-containing particle dispersion A-1, except that the rotation speed of the wet bead mill was set to 10 rpm. [Production Example of Cerium-Containing Particle Dispersion A-3] A cerium-containing particle dispersion A-3 was obtained by carrying out the same treatment as for the cerium-containing particle dispersion A-1, except that the concentration of cerium oxide was 10 mass %. [Production Example of Cerium-Containing Particle Dispersion A-4] 200 g of high-purity cerium oxide powder obtained using cerium nitrate as a starting material, 20 g of acetic acid, and 780 g of ultrapure water were mixed and dispersed in a wet high-pressure jet mill (manufactured by Sugino Machine, Starburst Lab) under the following conditions to obtain cerium-containing particle dispersion A-4. <Crushing conditions> Pressure: 200MPa Number of passes: 10 Chiller temperature: 20℃ [Production Example of Cerium-Containing Particle Dispersion A-5] A cerium-containing particle dispersion A-5 was obtained by carrying out the same treatment as for the cerium-containing particle dispersion A-4, except that the pressure of the wet high-pressure jet mill was set to 150 MPa. [Production Example of Cerium-Containing Particle Dispersion A-6] A cerium-containing particle dispersion A-6 was obtained by carrying out the same treatment as for the cerium-containing particle dispersion A-1, except that the rotation speed of the wet bead mill was 10 rpm and the treatment time was 10 minutes. [Production Example of Cerium-Containing Particle Dispersion A-7] A cerium-containing particle dispersion A-7 was obtained by carrying out the same treatment as for the cerium-containing particle dispersion A-1, except that the rotation speed of the wet bead mill was set to 12 rpm.

[0057] [Table 1]

[0058] 3. Preparation of Polishing Composition (Examples 1 to 6 and Comparative Examples 1 to 4) A dispersion of cerium-containing particles (component A) (cerium-containing particle dispersions A-1 to A-7 shown in Table 1), a compound (component B) shown in Table 2, and water were mixed to prepare a concentrate of a polishing liquid composition (concentration ratio: 10 times). The content (effective amount, mass %) of each component in each concentrate is as shown in Table 2. The content of water in the concentrate is the remainder excluding components A and B. The pH of the concentrate at 25° C. was 4.5. Thereafter, the polishing liquid concentrate was diluted 10-fold with ultrapure water to obtain the polishing liquid compositions of Examples 1 to 6 and Comparative Examples 1 to 4 shown in Table 2. The content (effective amount, mass %) of each component in each polishing liquid composition is as shown in Table 2. The content of water in the polishing liquid composition is the remainder excluding component A and component B. The polishing compositions of Examples 1 to 6 and Comparative Examples 1 to 4 had a pH of 5 at 25° C. The pH was adjusted using ammonia or nitric acid as necessary.

[0059] Details of the component B used in preparing each polishing composition are as follows. B-1: 2-Hydroxypyridine N-oxide (Tokyo Chemical Industry Co., Ltd.) B-2: Phenylphosphinic acid (Tokyo Chemical Industry Co., Ltd.)

[0060] 4. Evaluation of Polishing Compositions (Examples 1 to 6 and Comparative Examples 1 to 4) (1) Storage stability of the concentrated polishing composition The prepared concentrate of the polishing composition was placed in a transparent polypropylene container and allowed to stand in a thermostatic chamber at 40° C. for one week. Thereafter, the concentrate of the polishing composition was taken out and subjected to an appearance inspection, and mainly polishing evaluation was performed, and the storage stability of the concentrate was evaluated.

[0061] (2) Removal speed and rate of change of silicon oxide film The following test pieces were polished under the following polishing conditions using the polishing compositions of Examples 1 to 6 and Comparative Examples 1 to 4 (immediately after preparation or after storage). Note that "after storage" refers to a polishing composition prepared using a concentrate after storage at 40°C for one week according to the storage method (1) above. "Immediately after preparation" refers to a polishing composition prepared without storing the concentrate (40°C for one week). The thickness of the silicon oxide film or silicon nitride film was measured before and after polishing using an optical interference film thickness measuring device ("VM-1230" manufactured by SCREEN Semiconductor Solutions Co., Ltd.) The results are shown in Table 2. The polishing rate of the silicon oxide film (film to be polished) was calculated by the following formula. Silicon oxide film polishing speed (nm / min) = [Silicon oxide film thickness before polishing (nm) - Silicon oxide film thickness after polishing (nm)] / Polishing time (min) The rate of change in the polishing rate was calculated by the following formula. Rate of change (%) = [(polishing speed after storage) - (polishing speed immediately after preparation)] / (polishing speed after storage) x 100

[0062] [Test piece] The test specimen was a 40 mm x 40 mm square piece cut out from a silicon wafer in which a 2000 nm thick silicon oxide film (blanket film) was formed on one side by the TEOS-plasma CVD method.

[0063] [Polishing conditions] Polishing equipment: Single-sided polishing machine [TriboLab CMP, manufactured by Bruker] Polishing pad: Hard urethane pad "IC-1000 / Suba400, manufactured by Nitta DuPont" Plate rotation speed: 100 rpm Head rotation speed: 107 rpm Polishing load: 350g / cm 2 Polishing liquid supply amount: 50mL / min Polishing time: 1 minute

[0064] [Table 2]

[0065] As shown in Table 2, Examples 1 to 6, in which the amount of cerium ions in the concentrate is 125 ppm or less, have superior storage stability of the concentrate and show less fluctuation in polishing performance (less change in polishing speed due to storage of the concentrate) compared to Comparative Examples 1 to 3, in which the amount of cerium ions in the concentrate exceeds 125 ppm, and are therefore found to be polishing liquid compositions with stable polishing performance. Example 1 was found to be a polishing liquid composition that can improve the polishing speed and has stable polishing performance compared to Comparative Example 4, which does not contain component B. [Industrial Applicability]

[0066] The polishing composition of the present disclosure is useful in a method for producing semiconductor substrates for high density or high integration.

Claims

1. A polishing composition or a concentrate thereof, comprising cerium-containing particles (component A), a compound capable of coordinating with cerium ions (component B), and water, A polishing composition or a concentrate thereof, wherein the amount of cerium ions in the polishing composition or the concentrate thereof is 125 ppm or less.

2. 2. The polishing composition or concentrate thereof according to claim 1, wherein the amount of cerium ions per 1 g of the cerium-containing particles (component A) in the polishing composition or concentrate thereof is 25 ppm or less.

3. The polishing composition or concentrate thereof according to claim 1 , wherein component A is cerium oxide particles.

4. The polishing composition or concentrate thereof according to claim 1 , wherein component A is in the form of particles that have been crushed or disintegrated by a wet method.

5. 5. The polishing composition or concentrate thereof according to claim 4, wherein component A is in the form of particles pulverized or disintegrated by a wet high-pressure jet mill.

6. The polishing composition or concentrate thereof according to claim 1 , wherein component B is an aromatic compound.

7. 2. The polishing composition or concentrate thereof according to claim 1, wherein Component B has at least one functional group selected from a carboxyl group, a phosphate group, a phosphite group, a phosphinic acid group, and a hydroxyl group.

8. 2. The polishing composition or concentrate thereof according to claim 1, wherein component B is at least one selected from the group consisting of 2-hydroxypyridine N-oxide, phenylphosphinic acid, and salts thereof.

9. A method for producing the polishing composition according to claim 1, comprising: A method for producing a polishing composition, comprising a step of diluting a concentrate of a polishing composition containing cerium-containing particles (component A), a compound capable of coordinating with cerium ions (component B), and water, wherein the amount of cerium ions is 125 ppm or less.

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

11. 10. 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 or a polishing composition produced by the method for producing a polishing composition according to claim 9.