Abrasive liquid composition for silicon oxide film

Abstract

To provide a polishing liquid composition for silicon oxide films which can improve the polishing rate of a convex portion of a silicon oxide film on a substrate surface (convex removable rate), a method for producing a semiconductor substrate using the same, and a method for polishing a substrate.SOLUTION: This invention relates to a polishing liquid composition for silicon oxide films that contains cerium oxide particles (component A), a heterocyclic aromatic compound (component B), and a water-based medium. The component A has an oxygen storage content of 50 μmol / g or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a polishing composition for silicon oxide films that contains cerium oxide particles, a method for producing a semiconductor substrate, and a method for polishing a substrate using the same. [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 composition for CMP containing wet ceria particles, a functionalized heterocycle, a pH adjuster, and an aqueous carrier, and having a pH of about 1 to 6. Claims 2 and 3 of the same document disclose that the wet ceria particles have a surface containing tridentate hydroxyl groups, and that the 2.0×10 -5 moles / m 2 The surface coverage of tridentate hydroxyl groups is 458 cm or more. -1 and 583 cm -1 Including the peak at 458 cm -1 Peak intensity at 583 cm vs. -1 is described as being 100 or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2018-512475 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the semiconductor industry has become highly integrated, and there is a demand for more complex and finer wiring. For this reason, in CMP, the grain size of the abrasive is reduced to reduce defects, but this causes a problem of a decrease in the polishing speed, and there is a demand for an improvement in the polishing speed of silicon oxide films. In particular, in the planarization process of the interlayer insulating film of a 3D NAND flash memory by CMP, there is a problem that the step difference of the surface unevenness of the silicon oxide film between the array part of the film stacked in a stepped manner on the polished substrate and its surrounding area is large, so that planarization by CMP takes a long time. For example, the reference International Conference on Planarization / CMP technology (ICPT), p106 (2016) proposes a method of miniaturizing the convex parts, improving the CMP efficiency, and shortening the polishing time by performing an extra-etching process before CMP as shown in Figure 2. On the other hand, with the increase in recording capacity, the thickness of the array part is further increased, and the step difference of the surface unevenness becomes even larger. Therefore, it is becoming increasingly necessary to remove such fine convex parts at high speed.

[0007] Therefore, the present disclosure provides a polishing composition for silicon oxide films that can improve the removal rate (protrusion removal rate) of protrusions of a silicon oxide film on a substrate surface, 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 for silicon oxide films, which contains cerium oxide particles (component A), a heteroaromatic compound (component B), and an aqueous medium, and in which component A has an oxygen storage capacity of 50 μmol / g or more.

[0009] In one aspect, the present disclosure relates to a polishing method comprising a step of polishing a film to be polished with the polishing liquid composition of the present disclosure, wherein the film to be polished is a silicon oxide film formed in the process of manufacturing a semiconductor substrate.

[0010] In one aspect, the present disclosure relates to a method for producing a semiconductor substrate, comprising a step of polishing a film to be polished with the polishing liquid composition described in the present disclosure. Effect of the Invention

[0011] According to one embodiment of the present disclosure, a polishing composition for silicon oxide films can be provided that can improve the removal rate of convex portions of a silicon oxide film on a substrate surface (protrusion removal rate). [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram for explaining the evaluation wafer. [Diagram 2] FIG. 2 is a schematic diagram for explaining extra etching before CMP of an interlayer insulating film of a 3D NAND flash memory. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In one aspect, the present disclosure is based on the finding that by combining cerium oxide (hereinafter also referred to as "ceria") particles having a predetermined oxygen storage capacity with a heteroaromatic compound, it is possible to improve the polishing rate (protrusion removal rate) of a silicon oxide film protrusion on a substrate surface, for example, the polishing rate of a silicon oxide film protrusion present on a substrate after extra etching.

[0014] 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") that contains cerium oxide particles (component A), a heteroaromatic compound (component B), and an aqueous medium, and that has an oxygen storage capacity of 50 μmol / g or more in component A. The polishing composition of the present disclosure can improve the removal rate of convex portions of a silicon oxide film on a substrate surface (protrusion removal rate).

[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. Ceria particles are generally used to polish silicon oxide films. Usually, the cerium in ceria particles is tetravalent, but occasionally oxygen (O) is lost to make it trivalent. It is thought that the trivalent cerium in the ceria particles weakens the Si-O bond in the silicon oxide film, weakening it and facilitating polishing. In the present disclosure, the combined use of ceria particles (component A) having a predetermined oxygen storage capacity and a heteroaromatic compound (component B) is believed to promote the adsorption of ceria particles to a silicon oxide film and improve the contact probability of ceria particles at convex portions, thereby improving the polishing speed (convex portion removal speed) of the convex portions of the silicon oxide film on the substrate surface. Furthermore, in addition to the above-mentioned effects, the heteroaromatic compound having reducing properties is believed to promote the loss of oxygen from the ceria particles, promote the weakening of the silicon oxide film, and further accelerate the polishing speed. However, the present disclosure need not be construed as being limited to these mechanisms.

[0016] [Polished film] In one or more embodiments, the polishing composition of the present disclosure is a polishing composition (polishing composition for silicon oxide film) used for polishing a silicon oxide film, and can be used in a process that requires polishing a silicon oxide film. For example, in one or more embodiments, the polishing composition of the present disclosure can be used for polishing a silicon oxide film performed in a process for forming an element isolation structure of a semiconductor substrate, polishing a silicon oxide film performed in a process for forming an interlayer insulating film, polishing a silicon oxide film performed in a process for forming embedded metal wiring, or polishing a silicon oxide film performed in a process for forming an embedded capacitor. In one or more embodiments, the polishing composition of the present disclosure can be used for manufacturing a three-dimensional semiconductor device such as a three-dimensional NAND flash memory. In particular, the polishing liquid composition of the present disclosure can be suitably used for polishing a substrate having a silicon oxide film convex portion. In one or more embodiments, the silicon oxide film convex portion is a convex portion of a silicon oxide film on a substrate surface, for example, a convex portion having a width of 10 μm to 500 μm and a height of 4 μm to 10 μm. In one or more embodiments, the silicon oxide film convex portion can be formed by extra-etching process before CMP of an interlayer insulating film of a three-dimensional NAND flash memory. In one or more embodiments, the silicon oxide film convex portion is a silicon oxide film convex portion on a substrate surface after extra-etching. In one or more embodiments, the substrate having a silicon oxide film convex portion is a substrate after extra-etching before CMP of an interlayer insulating film of a three-dimensional NAND flash memory. In one or more embodiments, the polishing liquid composition of the present disclosure is for polishing a substrate after extra-etching.

[0017] [Cerium oxide (ceria) particles (component A)] The polishing liquid composition of the present disclosure contains ceria particles (hereinafter, also simply referred to as "Component A") as polishing abrasive grains. Component A may be one type or a combination of two or more types.

[0018] From the viewpoint of improving the polishing speed (protrusion removal speed) of the silicon oxide film protrusions, it is preferable that the component A has a high oxygen storage capacity. In the present disclosure, the oxygen storage capacity refers to the function of absorbing and releasing oxygen in association with the oxidation and reduction of cerium ions, and it can be determined that the larger the oxygen storage capacity, the better the oxygen storage capacity and the higher the oxidation and reduction characteristics. From the viewpoint of improving the polishing speed (protrusion removal speed) of the silicon oxide film protrusions, the oxygen storage capacity of the component A is 50 μmol / g or more, preferably 75 μmol / g or more, more preferably 100 μmol / g or more, even more preferably 125 μmol / g or more, and even more preferably 150 μmol / g or more. In addition, from the viewpoint of the long-term stability of the ceria particles, the oxygen storage capacity of the component A is preferably 500 μmol / g or less, more preferably 300 μmol / g or less, and even more preferably 250 μmol / g or less. In the present disclosure, the oxygen storage capacity can be measured using a thermogravimetric differential thermal analyzer, and specifically, can be measured by the method described in the Examples. The oxygen storage capacity of component A can be adjusted by controlling the crystallinity of the ceria particles.

[0019] There may be no particular limitation on the manufacturing method, shape, and surface state of Component A. 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 ceria. One embodiment of the pulverized ceria includes sintered pulverized ceria obtained by sintering and pulverizing a cerium compound such as cerium carbonate or cerium nitrate. Other embodiments of the pulverized ceria include single crystal pulverized ceria obtained by wet pulverizing ceria particles in the presence of an inorganic acid or an organic acid. Examples of the inorganic acid used in the wet pulverization 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 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] Examples of the shape of Component A include a substantially spherical shape, a polyhedral shape, and a raspberry shape.

[0021] From the viewpoint of improving the polishing speed of the convex parts of the silicon oxide film (protrusion removal speed), the average primary particle diameter of component A is preferably 5 nm or more, and more preferably 10 nm or more, and from the viewpoint of suppressing the occurrence of polishing scratches, the average primary particle diameter of component A is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 100 nm or less, and even more preferably 45 nm or less. From the same viewpoint, the average primary particle diameter of component A is preferably 5 nm or more and 300 nm or less, more preferably 10 nm or more and 200 nm or less, even more preferably 10 nm or more and 100 nm or less, and even more preferably 10 nm or more and 45 nm or less. In the present disclosure, the average primary particle diameter of component A is determined based on the BET specific surface area S (m 2 The BET specific surface area can be measured by the method described in the Examples.

[0022] The content of component A in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, even more preferably 0.4% by mass or more, and from the viewpoint of reducing costs, is preferably 5% by mass or less, more preferably 2.5% by mass or less, and even more preferably 1% by mass or less, when the total content of component A, component B, and water is 100% by mass. From the same viewpoint, the content of component A in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 2.5% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less. When component A is a combination of two or more types of ceria particles, the content of component A refers to the total content thereof.

[0023] [Heteroaromatic compounds (component B)] In one or more embodiments, the heteroaromatic compound (hereinafter, also simply referred to as "component B") contained in the polishing composition of the present disclosure may be a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom is substituted with a hydroxyl group, a thiol group, or a carboxyl group, from the viewpoint of improving the polishing rate of the convex portions of the silicon oxide film (convex portion removal rate), and a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom is substituted with a hydroxyl group or a thiol group is preferred, and a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom is substituted with a hydroxyl group is more preferred. Component B may be one type or a combination of two or more types.

[0024] As component B, from the viewpoint of improving the polishing rate (protrusion elimination rate) of the silicon oxide film protrusions, an N-oxide compound or a salt thereof (hereinafter also referred to as "component B1") containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group, an N-oxide compound or a salt thereof (hereinafter also referred to as "component B2") containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a thiol group, and a compound or a salt thereof (hereinafter also referred to as "component B3") containing a nitrogen-containing heteroaromatic ring skeleton having at least one carboxyl group are preferably selected. At least one selected from an N-oxide compound or a salt thereof (component B1) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group, and an N-oxide compound or a salt thereof (component B2) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a thiol group is more preferable. An N-oxide compound or a salt thereof (component B1) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group is even more preferable.

[0025] In the present disclosure, the N-oxide compound refers to, in one or more embodiments, a compound having an N-oxide group (N→O group). The N-oxide compound can have one or more N→O groups. From the viewpoint of easy availability, the number of N→O groups is preferably one.

[0026] <N-oxide compound (component B1)> Component B contained in the polishing liquid composition of the present disclosure is, in one or more embodiments, an N-oxide compound or a salt thereof (component B1) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom of the nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group. Examples of the above salts include alkali metal salts, alkaline earth metal salts, organic amine salts, ammonium salts, and the like. Component B1 may be used alone or in a combination of two or more.

[0027] In the present disclosure, the "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 the 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. Examples of the nitrogen-containing heteroaromatic ring contained in component B1 include, in one or more embodiments, a monocyclic or bicyclic condensed ring. The number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in component B1 is, in one or more embodiments, 1 to 3, and from the viewpoint of improving the polishing rate (protrusion elimination rate) of the silicon oxide film protrusion, 1 or 2 is preferable, and 1 is more preferable. Examples of the nitrogen-containing heteroaromatic ring skeleton contained in component B1 include, in one or more embodiments, 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 the nitrogen atom contained in the pyridine ring forms an N-oxide. The quinoline N-oxide skeleton refers to a structure in which the nitrogen atom contained in the quinoline ring forms an N-oxide.

[0028] Examples of component B1 include, in one or more embodiments, 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 (protrusion elimination rate) of the silicon oxide film protrusion, 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.

[0029] Examples of component B1 include at least one selected from 2-hydroxypyridine N-oxide and salts thereof.

[0030] <N-oxide compound (component B2)> In one or more embodiments, component B contained in the polishing liquid composition of the present disclosure is an N-oxide compound or a salt thereof (component B2) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom of the nitrogen-containing heteroaromatic ring skeleton is substituted with a thiol group. Examples of the salt include alkali metal salts, alkaline earth metal salts, organic amine salts, and ammonium salts. Component B2 may be used alone or in combination of two or more kinds.

[0031] In the present disclosure, the term "nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a thiol group" refers to a structure in which at least one hydrogen atom of a nitrogen-containing heteroaromatic ring is substituted with a thiol group. In the present disclosure, at least one nitrogen atom contained in the nitrogen-containing heteroaromatic ring skeleton of component B2 forms an N-oxide. In one or more embodiments, the nitrogen-containing heteroaromatic ring contained in component B2 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 B2 may be 1 to 3, and from the viewpoint of improving the polishing speed of the convex parts of the silicon oxide film (convex part removal speed), 1 or 2 is preferable, and 1 is more preferable. In one or more embodiments, the nitrogen-containing heteroaromatic ring skeleton contained in component B2 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.

[0032] In one or more embodiments, component B2 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 thiol group (-SH), an N-oxide compound having a quinoline ring in which at least one hydrogen atom of the quinoline ring is substituted with a thiol group (-SH), and salts thereof. Among these, from the viewpoint of improving the polishing speed of the convex portions of the silicon oxide film (convex portion removal speed), component B2 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 thiol group (-SH) or a salt thereof.

[0033] Examples of component B2 include 2-mercaptopyridine N-oxide and a salt thereof.

[0034] <Nitrogen-containing heteroaromatic ring compound (component B3)> In one or more embodiments, component B contained in the polishing liquid composition of the present disclosure is a compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a carboxyl group, or a salt thereof (component B3). Examples of the salt include alkali metal salts, alkaline earth metal salts, organic amine salts such as ethanolamine salts, and ammonium salts. Component B3 may be used alone or in combination of two or more kinds.

[0035] In one or more embodiments, the nitrogen-containing heteroaromatic ring contained in Component B3 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 B3 may be 1 to 3, and from the viewpoint of improving the polishing speed of the convex parts of the silicon oxide film (convex part removal speed), 1 or 2 is preferable, and 1 is more preferable. In one or a plurality of embodiments, the nitrogen-containing heteroaromatic ring skeleton contained in Component B3 may be a pyridine skeleton.

[0036] As component B3, a compound having at least one carboxyl group on a pyridine ring or a salt thereof is preferable, and examples thereof include picolinic acid, picolinic acid N-oxide, nicotinic acid, isonicotinic acid, and the like.

[0037] From the viewpoint of improving the polishing rate (protrusion removal rate) of the silicon oxide film protrusions, component B is preferably a compound having a reduction potential of 0.45 V or more when a 10 ppm aqueous solution of component B is measured by cyclic voltammetry (Ag / AgCl electrode standard, 25° C.). From the viewpoint of improving the polishing rate (protrusion removal rate) of the silicon oxide film protrusions, the reduction potential is preferably 0.45 V or more, more preferably 0.50 V or more, even more preferably 0.55 V or more, even more preferably 0.60 V or more, even more preferably 0.65 V or more, even more preferably 0.70 V or more, even more preferably 0.75 V or more, even more preferably 0.80 V or more, even more preferably 0.85 V or more, and preferably 0.95 V or less, more preferably 0.90 V or less. The reduction potential can be measured by the method described in the Examples.

[0038] In one or more embodiments, 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, from the viewpoint of improving the polishing rate of the silicon oxide film convex parts (convex part removal rate), and from the viewpoint of ensuring the dispersibility of the ceria particles, it is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. From the same viewpoint, the content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.005% by mass or more and 0.5% by mass or less, more preferably 0.005% by mass or more and 0.1% by mass or less, and even more preferably 0.005% by mass or more and 0.05% 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.

[0039] In one or more embodiments, from the viewpoint of improving the polishing rate of convex portions of a silicon oxide film (protrusion removal rate), the mass ratio A / B of components A and B (content of component A / content of component B) in the polishing liquid composition of the present disclosure is more preferably 1 or more, even more preferably 5 or more, even more preferably 10 or more, even more preferably 20 or more, even more preferably 26 or more, even more preferably 32 or more, and preferably 100 or less, more preferably 50 or less, and even more preferably 40 or less. From the same viewpoint, the mass ratio A / B in the polishing liquid composition of the present disclosure is preferably 1 or more and 100 or less, more preferably 5 or more and 50 or less, and even more preferably 10 or more and 40 or less.

[0040] [Aqueous medium] The aqueous medium contained in the polishing liquid composition of the present disclosure includes water such as distilled water, ion-exchanged water, pure water, and ultrapure water, or a mixed solvent of water and a solvent. The above-mentioned solvent includes a solvent miscible with water (for example, alcohol such as ethanol). When the aqueous medium is a mixed solvent of water and a solvent, the ratio of water to the entire mixed medium is not particularly limited as long as the effect of the present disclosure is not hindered, and from the viewpoint of economy, for example, 95 mass% or more is preferable, 98 mass% or more is more preferable, and substantially 100 mass% is even more preferable. From the viewpoint of surface cleanliness of the polished substrate, 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 liquid composition of the present disclosure can be the remainder excluding component A, component B, and optional components described below that are blended as necessary.

[0041] [Compound represented by formula (I) (Component C)] The polishing composition of the present disclosure may further contain a compound represented by the following formula (I) (hereinafter, simply referred to as "Component C") from the viewpoint of further improving the polishing rate of the convex parts of the silicon oxide film (convex part removal rate). Component C may be one type or a combination of two or more types.

[0042] [ka]

[0043] In the formula (I), R 1 and R 2 are the same or different and each represents a hydroxyl group or a salt thereof; R 3 -H, -NH 2 , -NHCH 3 , -NC 2 H 6 , -N + (CH 3 ) 3 , an alkyl group, a phenyl group, a cytidine group, a guanidino group, or an alkylguanidino group; X represents a bond or an alkylene group having 1 to 12 carbon atoms; and n represents 0 or 1.

[0044] In formula (I), R 1 and R 2 From the viewpoint of solubility in the polishing composition, each of the groups is preferably a hydroxyl group. R 3 From the viewpoint of further improving the polishing speed of the silicon oxide film protrusions (protrusion removal speed), 2 , -N + (CH 3 ) 3 , an alkyl group, a phenyl group, a cytidine group, or an alkylguanidino group is preferred, an alkylguanidino group or a phenyl group is more preferred, and an alkylguanidino group is even more preferred. As the alkyl group, from the viewpoint of solubility in the polishing liquid composition, 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 further improving the polishing speed of the convex parts of the silicon oxide film (convex part removal speed), 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. From the viewpoint of further improving the polishing rate of the convex portions of the silicon oxide film (convex portion removal rate), X is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, even more preferably an alkylene group having 1 to 8 carbon atoms, even more preferably an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 4 carbon atoms, even more preferably an alkylene group having 2 or 3 carbon atoms, and preferably an alkylene group having 2 carbon atoms (ethylene group). n is preferably 1 from the viewpoint of further improving the polishing speed of the convex parts of the silicon oxide film (convex part removal speed).

[0045] Examples of component C include creatinol phosphate, O-phosphorylethanolamine, sodium phosphocholine chloride hydrate, butylphosphonic acid, phenylphosphonic acid, cytidine 5-phosphate, etc. Among these, from the viewpoints of further improving the polishing rate of the silicon oxide film convex parts (convex part removal rate) and availability, it is preferable that component C is at least one selected from creatinol phosphate, phenylphosphonic acid, and salts thereof.

[0046] The content of component C in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.0015% by mass or more, and even more preferably 0.002% by mass or more, from the viewpoint of improving the polishing rate of the silicon oxide film convex parts (convex part removal rate). From the viewpoint of ensuring the dispersibility of the ceria particles, it is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. From the same viewpoint, the content of component C in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.0015% by mass or more and 0.1% by mass or less, and even more preferably 0.002% by mass or more and 0.05% by mass or less. When component C is a combination of two or more kinds, the content of component C refers to the total content thereof.

[0047] [Other ingredients] The polishing liquid composition 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 rate enhancers, and counter ions. When the polishing liquid composition of the present disclosure further contains other components, the content of the other 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.

[0048] [Polishing liquid composition] The polishing liquid composition of the present disclosure can be produced, for example, by a production method including a step of blending component A, component B, and an aqueous medium, and, if desired, the above-mentioned optional components (component C, other components) by a known method. For example, the polishing liquid composition of the present disclosure can be produced by blending at least component A, component B, and an aqueous medium. When component A is a combination of multiple types of ceria particles, component A can be obtained by blending multiple types of ceria particles. When component B is a combination of multiple types of heteroaromatic compounds, component B can be obtained by blending multiple types of heteroaromatic compounds. In the present disclosure, "blending" includes mixing component A, component B, and an aqueous medium, and, if necessary, the above-mentioned optional components (component C, 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, a homogenizer, an ultrasonic disperser, and a wet ball mill. The blending amount of each component in the manufacturing method of the polishing liquid composition of the present disclosure can be the same as the content of each component in the above-mentioned polishing liquid composition of the present disclosure.

[0049] 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.

[0050] From the viewpoint of improving the polishing rate of the silicon oxide film convex parts (convex part removal rate), the pH of the polishing liquid composition of the present disclosure is preferably 3.5 or more, more preferably 4 or more, and even more preferably 4.5 or more, and is preferably 9 or less, more preferably 8.5 or less, even more preferably 8 or less, even more preferably less than 8, even more preferably 7 or less, and even more preferably 6 or less. From the same viewpoint, the pH of the polishing liquid composition of the present disclosure is preferably 3.5 or more and 9 or less, more preferably 4 or more and 8.5 or less, even more preferably 4.5 or more and 8 or less, even more preferably 4.5 or more and less than 8, even more preferably 4.5 or more and 7 or less, and even more preferably 4.5 or more and 6 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.

[0051] 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 is started to be used for polishing. The polishing liquid composition of the present disclosure may be stored and supplied in a concentrated state within a range in which its stability is not impaired. In this case, it is preferable in that the manufacturing and transportation costs can be reduced. And, this concentrated liquid can be appropriately diluted with water as necessary and used in the polishing process. The dilution ratio is preferably 5 to 100 times.

[0052] [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 polishing abrasive dispersion containing component A and an aqueous medium, and an additive aqueous solution containing component B in a mutually unmixed state. The polishing abrasive dispersion and the additive aqueous solution are mixed at the time of use, and diluted with an aqueous medium as necessary. The aqueous medium contained in the polishing abrasive dispersion may be the entire amount of the aqueous medium used to prepare the polishing liquid composition, or may be a part of the aqueous medium. The additive aqueous solution may contain a part of the aqueous medium used to prepare the polishing liquid composition. The polishing abrasive dispersion and the additive aqueous solution may each contain the above-mentioned optional components (component C, other components) as necessary. According to the polishing liquid kit of the present disclosure, it is possible to obtain a polishing liquid composition that can improve the polishing rate of convex parts of a silicon oxide film (convex part removal rate).

[0053] [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, 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. For example, in one or more embodiments, the film to be polished in the polishing method of the present disclosure is a silicon oxide film convex portion on the substrate surface after extra etching. In one or more embodiments, the polishing method of the present disclosure includes a step of polishing a substrate to be polished using the polishing liquid composition of the present disclosure. In one or more embodiments, the substrate to be polished is a substrate after extra etching, and in one or more embodiments, a substrate having a silicon oxide film convex portion. By using the polishing method of the present disclosure, it is possible to improve the polishing speed (convex portion removal speed) of the silicon oxide film convex portion, and therefore an 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 semiconductor substrates of the present disclosure described below.

[0054] [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 (polishing step) using the polishing liquid composition of the present disclosure. Examples of the film to be polished include the film to be polished in the polishing liquid composition of the present disclosure. For example, in one or more embodiments, the film to be polished in the method for producing a semiconductor substrate of the present disclosure is a silicon oxide film convex portion on the substrate surface after extra etching. In one or more embodiments, the method for producing a semiconductor substrate of the present disclosure includes a step of polishing a substrate to be polished using the polishing liquid composition of the present disclosure. In one or more embodiments, the substrate to be polished is a substrate after extra etching, and in one or more embodiments, a substrate having a silicon oxide film convex portion. According to the method for producing a semiconductor substrate of the present disclosure, it is possible to improve the polishing speed of the silicon oxide film convex portion (convex portion removal speed), and therefore an effect of efficiently producing a semiconductor substrate with improved quality can be achieved.

[0055] As a specific example of the method for manufacturing a semiconductor substrate according to the present disclosure, first, a silicon dioxide film is formed on a silicon substrate, and then a silicon nitride (Si 3 N 4 ) films are alternately laminated. After that, a channel is formed using polysilicon, the laminated film is trimmed, a charge trapping layer is formed, and a tungsten (W) gate is formed to form an array. After that, a silicon dioxide layer is laminated on the array using a method such as CVD (chemical vapor deposition). The silicon oxide film formed in this way has a large step difference between the array section and the periphery. Next, the silicon oxide film in the array section is polished by CMP until it is the same height as the periphery. A method has been proposed in which, as shown in Figure 2, an extra-etching process is performed before CMP to make the convex sections finer, improve CMP efficiency, and shorten the polishing time. In one or more embodiments, the polishing liquid composition of the present disclosure can be suitably used for polishing a substrate having a silicon oxide film protrusion after extra etching. In one or more embodiments, the silicon oxide film protrusion refers to a silicon oxide film protrusion on the substrate surface, and examples of the protrusion include a protrusion having a width of 10 μm to 500 μm and a height of 4 μm to 10 μm.

[0056] 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.

[0057] 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.

[0058] 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

[0059] Hereinafter, the present disclosure will be described with reference to examples, but the present disclosure is not limited thereto.

[0060] 1.Measuring methods for each parameter (1) pH of the polishing composition The pH value of the polishing composition at 25°C was measured using a pH meter (manufactured by Toa Denpa Kogyo Co., Ltd., "HM-30G"), and was the value measured one minute after the pH meter electrode was immersed in the polishing composition.

[0061] (2) Average primary particle size of ceria particles (component A) The average primary particle size (nm) of the ceria particles (component A) is determined by the specific surface area S (m 2 / g) to obtain the true density of ceria particles of 7.2 g / cm 3 It was calculated as:

[0062] (3) BET specific surface area of ​​ceria particles (component A) The specific surface area was measured by the nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritic automatic specific surface area measuring device "Flowsorb III2305", Shimadzu Corporation) after drying the ceria dispersion for 3 hours with hot air at 120°C and then pulverizing it finely in an agate mortar to obtain a sample.

[0063] (4) Oxygen storage capacity of ceria particles The oxygen storage capacity of the ceria particles was measured by a thermogravimetric differential thermal analyzer (Thermo plus TG8110, manufactured by Rigaku) ​​according to the method described below. The ceria dispersion was dried with hot air at 600°C for 3 hours, and then finely crushed in an agate mortar. The ceria particles were then placed in a Pt pan and set in the device. The device was filled with nitrogen:hydrogen gas (1:1), and the temperature was raised from room temperature to 800°C to reduce the ceria particles. While maintaining the temperature at 800°C, the system was replaced with nitrogen and maintained for 30 minutes. Next, the ceria particles were oxidized with oxygen:nitrogen gas (1:9). The amount of oxygen absorbed by the ceria particles at this time was used to calculate the oxygen storage amount (μmol / g).

[0064] (5) Reduction potential 1) Prepare an aqueous solution of sodium sulfate to be used as a supporting electrolyte at 0.1 mol / L using ultrapure water, and replace with nitrogen for at least 3 hours. 2) Weigh out 9.9 mL of sodium sulfate solution into a glass vial (20 mL). 3) The surface of the glassy carbon working electrode is polished thoroughly using a 1 μm polishing diamond and diamond polishing pad (both manufactured by BAS) by pressing the electrode vertically and drawing a figure 8. Next, using a 0.05 μm alumina and alumina polishing pad (both manufactured by BAS), the electrode surface is polished thoroughly by drawing a figure 8 until it becomes a mirror surface. After that, the electrode surface is washed with ultrapure water and dried. 4) Connect the glassy carbon electrode, silver / silver chloride reference electrode, and platinum counter electrode to an ALS electrochemical analyzer (Model 611D) and immerse it in the sodium sulfate aqueous solution to assemble a three-electrode electrochemical cell. 5) Set the cyclic voltammetry variables as follows: high potential 1 V, low potential 1 V, scan rate 0.1 V / s, sweep segment 5 w, and display the potential-current data points on the monitor. 6) After thoroughly replacing the nitrogen gas in the glass vial by inserting a Teflon tube into the vial, the measurement is performed using only the supporting electrolyte. If the nitrogen replacement is insufficient, a peak due to dissolved oxygen will be detected. 7) A measurement sample (additive: 1000 ppm) was prepared in ultrapure water and thoroughly substituted with nitrogen. After that, 0.1 mL of the measurement sample was added to 9.9 mL of an aqueous sodium sulfate solution in a glass vial to obtain a 10 ppm aqueous solution of the additive. 8) Measure the open circuit potential, set it as the initial potential of the cyclic voltammetry variable, and perform the measurement. At this time, confirm that no peaks due to dissolved oxygen are detected, and confirm the redox potential from the cyclic voltammogram derived from the measurement sample.

[0065] 2. Preparation of Polishing Composition (Examples 1 to 12 and Comparative Examples 1 to 2) (Examples 1 to 9, 12 and Comparative Examples 1 to 2) Ceria particles (component A shown in Tables 1 and 3), a heteroaromatic compound (component B shown in Tables 2 and 3), and water were mixed to obtain polishing liquid compositions of Examples 1 to 9 and 12 and Comparative Examples 1 and 2. The content of each component in each polishing liquid composition is as shown in Table 3. The content of water is the remainder excluding components A and B. (Examples 10 to 11) Ceria particles (component A shown in Tables 1 and 3), a heteroaromatic compound (component B shown in Tables 2 and 3), a compound (component C shown in Table 3), and water were mixed to obtain the polishing liquid compositions of Examples 10 and 11. The content of each component in each polishing liquid composition is as shown in Table 3. The content of water is the remainder excluding components A, B, and C. The polishing compositions of Examples 1 to 12 and Comparative Examples 1 and 2 had a pH of 5. The pH was adjusted using ammonia or nitric acid.

[0066] Details of Components A, B, and C used in preparing the polishing compositions of Examples 1 to 12 and Comparative Examples 1 and 2 are shown in Tables 1 and 2 and below. (Component B) B1: 2-Hydroxypyridine N-oxide (Tokyo Chemical Industry Co., Ltd.) B2: 2-mercaptopyridine N-oxide (Tokyo Chemical Industry Co., Ltd.) B3: Picolinic acid (Tokyo Chemical Industry Co., Ltd.) (Component C) C1: Creatinol phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) [In formula (I), R 1 :OH,R 2 :OH,R 3 : 1-methylguanidino group, X: ethylene group, n: 1. C2: Phenylphosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) [In formula (I), R 1 :OH,R 2 :OH,R 3 : phenyl group, X: bond, n: 0.

[0067] [Table 1]

[0068] [Table 2]

[0069] 3. Evaluation of Polishing Compositions (Examples 1 to 12 and Comparative Examples 1 to 2) [Evaluation sample] The wafer (diameter 200 mm) shown in Figure 1 was used as the evaluation sample. This evaluation sample was prepared by forming a silicon oxide film with a thickness of 6 μm on a silicon substrate, and then forming a lattice-shaped concave-convex portion by dry etching, as shown in Figure 1. The concave portion had dimensions of 20 mm length x 20 mm width x 4 μm depth. The silicon oxide film was made of P-TEOS. This evaluation sample was a model substrate of a substrate having a silicon oxide film convex portion after extra etching.

[0070] [Polishing conditions] Polishing equipment: Single-sided polishing machine [Ebara Corporation, FREX-200] Polishing pad: Hard urethane pad "IC-1000 / Suba400" [manufactured by Nitta Haas] Plate rotation speed: 100 rpm Head rotation speed: 107 rpm Polishing load: 280hPa Polishing liquid supply amount: 200mL / min Polishing time: 1 minute

[0071] [Bump elimination speed] Using each of the polishing compositions of Examples 1 to 12 and Comparative Examples 1 and 2, evaluation samples were polished under the above polishing conditions. The thickness of the silicon oxide film on the convex portion with a wiring width of 500 μm before and after polishing was measured using ASET-F5X (manufactured by KLA). The convex portion removal rate was calculated using the following formula, and the results are shown in Table 3, where the polishing rate in Comparative Example 1 was taken as 100. Convex part elimination rate = [Thickness of silicon oxide film on convex part before polishing (Å) - Thickness of silicon oxide film on convex part after polishing (Å)] / Polishing time (min)

[0072] [Table 3]

[0073] As shown in Table 3, Examples 1 to 12, in which cerium oxide particles having an oxygen storage capacity of 50 μmol / g or more were used in combination with a heteroaromatic compound, showed improved projection elimination rates compared to Comparative Example 1, in which cerium oxide particles having an oxygen storage capacity of less than 50 μmol / g were used. In Comparative Example 2, in which cerium oxide particles having an oxygen storage capacity of 50 μmol / g or more were used but a heteroaromatic compound was not used, polishing did not progress. [Industrial Applicability]

[0074] The polishing composition of the present disclosure is useful in a method for producing semiconductor substrates for high density or high integration.

Claims

1. The composition contains cerium oxide particles (component A), a heteroaromatic compound (component B), an aqueous medium, and a compound represented by the following formula (I) (component C), A polishing composition for silicon oxide films, wherein component A has an oxygen storage capacity of 50 μmol / g or more. 【Chemistry 1】 In the above formula (I), R 1 and R 2 are the same or different and represent a hydroxyl group or a salt thereof; R 3 represents H, --NH 2 , --NHCH 3 , --NC 2 H 6 , --N + (CH 3 ) 3 , an alkyl group, a phenyl group, a cytidine group, a guanidino group or an alkylguanidino group; X represents a bond or an alkylene group having 1 to 12 carbon atoms; and n represents 0 or 1.

2. 2. The polishing composition according to claim 1, wherein the oxygen storage capacity of Component A is 100 μmol / g or more.

3. 3. The polishing composition according to claim 1, wherein component B is a compound having a reduction potential of 0.45 V or more when a 10 ppm aqueous solution of component B is measured by cyclic voltammetry (Ag / AgCl electrode standard, 25° C.).

4. 4. The polishing composition according to claim 1, wherein Component B is a nitrogen-containing heteroaromatic compound in which at least one hydrogen atom is substituted with a hydroxyl group.

5. 5. The polishing composition according to claim 1, wherein component B is at least one selected from the group consisting of an N-oxide compound having a pyridine ring in which at least one hydrogen atom of the pyridine ring is substituted with a hydroxyl group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom of the quinoline ring is substituted with a hydroxyl group, and salts thereof.

6. 6. The polishing composition according to claim 1, wherein Component B is at least one selected from the group consisting of 2-hydroxypyridine N-oxide and salts thereof.

7. 2. The polishing composition according to claim 1, wherein component C is at least one selected from the group consisting of creatinol phosphate, phenylphosphonic acid, and salts thereof.

8. The polishing composition according to claim 1 , for polishing a substrate after extra etching.

9. 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 course of manufacturing a semiconductor substrate.

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 .

11. 11. The method according to claim 9, wherein the film to be polished is a convex portion of a silicon oxide film on a substrate surface after extra etching.

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