Abrasive slurry composition for silicon oxide films

Abstract

The present invention provides, in one embodiment, a polishing liquid composition capable of improving the polishing speed of a silicon oxide film. The present invention relates, in one embodiment, to a polishing liquid composition for a silicon oxide film, comprising cerium oxide particles (component A), an additive (component B), and an aqueous medium, 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 reference).

Description

Technical Field

[0001] The present invention relates to a polishing liquid composition for silicon oxide film containing cerium oxide particles, a method for producing a semiconductor substrate using the same, and a method for polishing the substrate. Background Art

[0002] The so-called chemical mechanical polishing (CMP) technology refers to the following technology: when the surface of the substrate to be processed is in contact with the polishing pad, the polishing liquid is supplied to their contact area, and the substrate to be polished and the polishing pad are moved relatively, thereby causing a chemical reaction on the surface uneven parts of the substrate to be polished, and mechanically removing them to make them flat.

[0003] At present, in the manufacturing process of semiconductor elements, this CMP technology becomes a necessary technology when flattening the interlayer insulating film, forming the shallow trench element separation structure (hereinafter also referred to as the "element separation structure"), forming the plug and embedded metal wiring, etc. In recent years, the multi-layer and high-precision semiconductor elements have developed by leaps and bounds, and the yield and production volume (yield) of semiconductor elements have begun to be required to be further improved. Along with this, the CMP process has also begun to expect grinding without grinding damage and at a higher speed. For example, in the process of forming the shallow trench element separation structure, it is expected that while the grinding speed is high, the grinding selectivity of the grinding stop film (for example, silicon nitride film) relative to the film to be ground (for example, silicon oxide film) is improved (in other words, the grinding selectivity that the grinding stop film is difficult to be ground compared to the film to be ground).

[0004] For example, Japanese Patent Application Publication No. 2018-512475 (Patent Document 1) proposes a CMP polishing liquid composition, which contains wet cerium oxide particles, a functionalized heterocycle, a pH adjuster, and an aqueous monomer, and has a pH value of about 1 to 6. In addition, it is described that additives such as picolinic acid N-oxide can be added to the polishing liquid composition (paragraph

[0064] of the document, Example 5).

[0005] Japanese Patent Application Publication No. 2015-195391 (Patent Document 2) proposes a CMP polishing liquid composition comprising an amine compound, a radical generating oxidant, a radical scavenger, and an aqueous carrier. An example of the radical scavenger is a hydroxy-substituted heterocyclic aromatic compound such as 2-hydroxypyridine, or an N-oxide compound such as 1-(2-carboxymethyl)piperazine-N-oxide (Claim 2, paragraphs

[0032] and

[0034] of the document, etc.).

[0006] On the other hand, it has been proposed to use a polishing liquid composition containing a compound having a quinoline structure in the polishing step of a glass hard disk substrate (for example, Japanese Patent Application Laid-Open No. 2016-122487 (Patent Document 3)). Summary of the invention

[0007] The present invention relates in one embodiment to a polishing liquid composition for silicon oxide film, which contains cerium oxide particles (component A), an additive (component B), and an aqueous medium, 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 reference). DETAILED DESCRIPTION

[0008] In recent years, the high integration in the semiconductor field has been gradually developed, requiring the wiring to be more complicated or finer. Therefore, in CMP polishing, the defects are reduced by reducing the particle size of the abrasive grains, but in this case, there is a problem of reduced polishing speed, requiring to increase the polishing speed of the silicon oxide film.

[0009] Therefore, the present invention provides a polishing liquid composition for silicon oxide film which can improve the polishing rate of silicon oxide film, a method for producing a semiconductor substrate using the same, and a method for polishing a substrate.

[0010] The present invention relates in one embodiment to a polishing liquid composition for silicon oxide film, which contains cerium oxide particles (component A), an additive (component B), and an aqueous medium, 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 reference).

[0011] In another embodiment, the present invention relates to a polishing liquid composition for silicon oxide film, which contains cerium oxide particles (component A), an additive (component B), and an aqueous medium, wherein component B is at least one selected from an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a hydroxyl group or a salt thereof (component B1), an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a thiol group or a salt thereof (component B2), and a compound containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group or a salt thereof (component B3).

[0012] In another aspect, the present invention relates to a method for producing a semiconductor substrate, comprising the step of polishing a film to be polished using the polishing composition of the present invention.

[0013] In another aspect, the present invention relates to a polishing method including the step of polishing a film to be polished using the polishing composition of the present invention.

[0014] According to one embodiment of the present invention, a polishing composition for a silicon oxide film that can increase the polishing rate of a silicon oxide film can be provided.

[0015] The present invention is based on the finding that the polishing rate of a silicon oxide film can be increased by causing a polishing composition containing cerium oxide (hereinafter also referred to as “ceria”) particles as abrasive grains to contain a compound having a reduction potential of 0.45 V or more.

[0016] That is, the present invention relates in one embodiment to a polishing liquid composition for silicon oxide film (hereinafter also referred to as "polishing liquid composition of the present embodiment 1"), which contains cerium oxide particles (component A), an additive (component B), and an aqueous medium, 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 reference). According to the polishing liquid composition of the present embodiment 1, the polishing speed of the silicon oxide film can be increased.

[0017] The details of the mechanism by which the effect of Embodiment 1 is manifested are not clear, but can be inferred as follows.

[0018] Generally, ceria particles are used for polishing silicon oxide films. Usually, the cerium in ceria particles is tetravalent, and occasionally oxygen (O) falls off and becomes trivalent. It is believed that the trivalent cerium in the ceria particles weakens the Si-O bond of the silicon oxide film, making the silicon oxide film fragile and promoting polishing.

[0019] In the present method 1, it is considered that by using cerium dioxide particles together with an additive (component B) which is a compound having a reduction potential greater than a specified value, component B reduces tetravalent cerium present on the surface of the cerium dioxide particles to trivalent cerium, and the ratio of trivalent cerium present in the cerium dioxide particles increases, thereby promoting the effect on the Si-O bonds of the silicon oxide film, advancing the embrittlement of the silicon oxide film, and improving the polishing rate.

[0020] However, the present invention should not be construed as being limited to these mechanisms.

[0021] In another aspect, the present invention is based on the finding that a polishing composition containing cerium oxide (ceria) particles as abrasive particles can increase the polishing rate when used for polishing a silicon oxide film if it contains a specific N-oxide compound or a specific nitrogen-containing heteroaromatic compound.

[0022] That is, the present invention relates to a polishing liquid composition for silicon oxide film (hereinafter also referred to as "polishing liquid composition of present embodiment 2") in another embodiment, which contains cerium oxide particles (component A), an additive (component B), and an aqueous medium, wherein component B is at least one selected from an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a hydroxyl group or a salt thereof (component B1), an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a thiol group or a salt thereof (component B2), and a compound containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group or a salt thereof (component B3). According to the polishing liquid composition of present embodiment 2, the polishing rate of silicon oxide film can be increased.

[0023] The details of the mechanism by which the effect of Embodiment 2 is manifested are not clear, but can be inferred as follows.

[0024] Generally, ceria particles are used for polishing silicon oxide films. Usually, the cerium in ceria particles is tetravalent, and occasionally oxygen (O) falls off and becomes trivalent. It is believed that the trivalent cerium in the ceria particles weakens the Si-O bond of the silicon oxide film, making the silicon oxide film fragile and promoting polishing.

[0025] In the present method 2, it is believed that by using ceria particles together with a specific N-oxide compound or a specific nitrogen-containing heteroaromatic ring compound (component B), the hydroxyl group or thiol group of component B reduces the tetravalent cerium present on the surface of the ceria particles to trivalent cerium, and the ratio of trivalent cerium present in the ceria particles increases, thereby promoting the effect on the Si-O bonds of the silicon oxide film, promoting the embrittlement of the silicon oxide film, and improving the polishing rate.

[0026] However, the present invention should not be construed as being limited to these mechanisms.

[0027] [Cerium oxide (ceria) particles (ingredient A)]

[0028] The polishing composition of the present invention contains ceria particles (hereinafter also referred to as "component A") as abrasive particles. Component A may be one kind or a combination of two or more kinds.

[0029] There is no particular limitation on the production method, shape, and surface state of component A. Examples of component A include colloidal ceria, amorphous ceria, and ceria-coated silica.

[0030] Colloidal ceria can be obtained by a build-up process using the method described in Examples 1 to 4 of JP-A-2010-505735, for example.

[0031] As amorphous ceria, for example, crushed ceria can be cited. As an embodiment of crushed ceria, for example, roasted and crushed ceria obtained by roasting and crushing cerium compounds such as cerium carbonate or cerium nitrate can be cited. As another embodiment of crushed ceria, for example, single crystal crushed ceria obtained by wet crushing ceria particles in the presence of an inorganic acid or an organic acid can be cited. As an inorganic acid used during wet crushing, for example, nitric acid can be cited, and as an organic acid, for example, an organic acid with a carboxyl group can be cited, specifically, at least one selected from picolinic acid, glutamic acid, aspartic acid, aminobenzoic acid and p-hydroxybenzoic acid can be cited. As a wet crushing method, for example, wet crushing using a planetary bead mill can be cited.

[0032] As the ceria-coated silicon oxide, for example, there can be mentioned a composite particle having a structure in which at least a portion of the surface of the silicon oxide particle is coated with granular ceria using the method described in Examples 1 to 14 of JP-A-2015-63451 or Examples 1 to 4 of JP-A-2013-119131, and the composite particle can be obtained, for example, by depositing ceria on silicon oxide particles.

[0033] Examples of the shape of component A include a substantially spherical shape, a polyhedral shape, and a raspberry shape.

[0034] Regarding the average primary particle size of component A, from the perspective of increasing the grinding speed, it is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 20 nm or more, and from the perspective of suppressing the generation of grinding damage, it is preferably 300 nm or less, more preferably 200 nm or less, and further preferably 150 nm or less. More specifically, the average primary particle size 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, and further preferably 20 nm or more and 150 nm or less. In the present invention, the average primary particle size of component A is calculated using the BET specific surface area S (m 2 The BET specific surface area can be measured by the method described in the Examples.

[0035] About the content of component A in the polishing liquid composition of the present invention, when the total content of component A, component B and water is set to 100 mass %, with respect to the viewpoint of improving polishing speed, preferably more than 0.001 mass %, more preferably more than 0.05 mass %, more preferably more than 0.07 mass %, more preferably more than 0.1 mass %, and, with respect to the same viewpoint, preferably less than 6 mass %, more preferably less than 1 mass %, more preferably less than 0.7 mass %, more preferably less than 0.5 mass %. More specifically, the content of component A is preferably more than 0.001 mass % and less than 6 mass %, more preferably more than 0.05 mass % and less than 1 mass %, more preferably more than 0.07 mass % and less than 0.7 mass %, more preferably more than 0.1 mass % and less than 0.5 mass %. In the case where component A is a combination of more than 2 kinds of cerium oxide particles, the content of component A refers to their total content.

[0036] [Additives (ingredient B)]

[0037] The additive (hereinafter also referred to as "component B") contained in the polishing liquid composition of the present invention 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 reference) in one or more embodiments. The above reduction potential is 0.45 V or more, preferably 0.50 V or more, more preferably 0.55 V or more, and preferably 0.95 V or less, more preferably 0.90 V or less, from the perspective of improving the polishing rate. The reduction potential can be measured by the method described in the examples.

[0038] As component B, in one or more embodiments, from the viewpoint of improving the polishing rate, it is preferred that when a 10 ppm aqueous solution of component B is measured using cyclic voltammetry (Ag / AgCl electrode reference), no oxidation potential is detected. In the present invention, the so-called "no oxidation potential is detected" refers to a state in which no oxidation potential is detected when a 10 ppm aqueous solution of component B is automatically measured using an ALS electrochemical analyzer (model 611D). Specifically, it refers to a state in which no oxidation potential is measured using the method described in the embodiments.

[0039] As component B, in one or more embodiments, with regard to the viewpoint of improving grinding speed, it is preferably a reducing compound containing heteroaromatic ring skeleton. As component B, for example, can be enumerated: N-oxide compound or its salt (hereinafter, also referred to as "component B1") containing at least one hydrogen atom through the nitrogen-containing heteroaromatic ring skeleton substituted by hydroxyl, N-oxide compound or its salt (hereinafter, also referred to as "component B2") containing at least one hydrogen atom through the nitrogen-containing heteroaromatic ring skeleton substituted by thiol group, compound or its salt (hereinafter, also referred to as "component B3") containing the nitrogen-containing heteroaromatic ring skeleton with at least one hydroxyl and at least one carbonyl, etc. Component B can be one, can also be a combination of more than two.

[0040] <N-oxide compound (component B1)>

[0041] In one embodiment, the component B contained in the polishing liquid composition of the present invention is an N-oxide compound or a salt thereof (component B1) containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom in the nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group. Examples of the above-mentioned salt include alkali metal salts, alkaline earth metal salts, organic amine salts, ammonium salts, etc. Component B1 can be used alone or in combination of two or more.

[0042] Therefore, the present invention relates in one embodiment to a polishing liquid composition for silicon oxide film, which contains cerium oxide particles (component A), an N-oxide compound (component B1), and an aqueous medium, wherein component B1 is an N-oxide compound or a salt thereof containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a hydroxyl group.

[0043] In this embodiment, the so-called N-oxide compound refers to a compound having an N-oxyl group (N→O group) in one or more embodiments. The N-oxide compound may have one or more N→O groups, and the number of N→O groups is preferably one from the perspective of easy availability.

[0044] In the present embodiment, the “nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group” means a structure in which at least one hydrogen atom in a nitrogen-containing heteroaromatic ring is substituted with a hydroxyl group.

[0045] In this embodiment, at least one nitrogen atom contained in the nitrogen-containing heteroaromatic ring skeleton of component B1 forms an N-oxide. As the nitrogen-containing heteroaromatic ring contained in component B1, in one or more embodiments, a monocyclic or bicyclic condensed ring can be cited. As the number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in component B1, in one or more embodiments, 1 to 3 can be cited, and from the perspective of increasing the polishing rate, 1 or 2 are preferred, and 1 is more preferred.

[0046] As the nitrogen-containing heteroaromatic ring skeleton contained in component B1, in one or more embodiments, at least one selected from the group consisting of a pyridine N-oxide skeleton, a quinoline N-oxide skeleton, etc. can be cited. In the present invention, the so-called pyridine N-oxide skeleton refers to a structure in which the nitrogen atom contained in the pyridine ring forms an N-oxide. The so-called quinoline N-oxide skeleton refers to a structure in which the nitrogen atom contained in the quinoline ring forms an N-oxide.

[0047] As component B1, 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 in the pyridine ring is substituted with a hydroxyl group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom in the quinoline ring is substituted with a hydroxyl group, and salts thereof can be cited. Among them, from the viewpoint of improving the polishing rate, as component B1, an N-oxide compound having a pyridine ring in which at least one hydrogen atom in the pyridine ring is substituted with a hydroxyl group or a salt thereof is preferred.

[0048] Specific examples of Component B1 include 2-hydroxypyridine N-oxide and the like.

[0049] <N-oxide compound (component B2)>

[0050] In another embodiment, the component B contained in the polishing liquid composition of the present invention 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 in the nitrogen-containing heteroaromatic ring skeleton is substituted by a thiol group. As the above-mentioned salt, alkali metal salts, alkaline earth metal salts, organic amine salts, ammonium salts, etc. can be cited. Component B2 can be used alone or in combination of two or more.

[0051] Therefore, the present invention, in another embodiment, relates to a polishing liquid composition for silicon oxide film, which contains cerium oxide particles (component A), an N-oxide compound (component B2), and an aqueous medium, wherein component B2 is an N-oxide compound or a salt thereof containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a thiol group.

[0052] In this embodiment, the so-called N-oxide compound refers to a compound having an N-oxyl group (N→O group) in one or more embodiments. The N-oxide compound may have one or more N→O groups, and the number of N→O groups is preferably one from the perspective of easy availability.

[0053] In the present embodiment, the “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 in the nitrogen-containing heteroaromatic ring is substituted with a thiol group.

[0054] In this embodiment, at least one nitrogen atom contained in the nitrogen-containing heteroaromatic ring skeleton of component B2 forms an N-oxide. As the nitrogen-containing heteroaromatic ring contained in component B2, in one or more embodiments, a monocyclic or bicyclic condensed ring can be cited. As the number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in component B2, in one or more embodiments, 1 to 3 can be cited, and from the perspective of improving the polishing rate, preferably 1 or 2, more preferably 1.

[0055] As the nitrogen-containing heteroaromatic ring skeleton contained in component B2, in one or more embodiments, at least one selected from the group consisting of a pyridine N-oxide skeleton, a quinoline N-oxide skeleton, etc. can be cited. In the present invention, the so-called pyridine N-oxide skeleton refers to a structure in which the nitrogen atom contained in the pyridine ring forms an N-oxide. The so-called quinoline N-oxide skeleton refers to a structure in which the nitrogen atom contained in the quinoline ring forms an N-oxide.

[0056] As component B2, in one or more embodiments, at least one selected from N-oxide compounds of pyridine rings in which at least one hydrogen atom in the pyridine ring is substituted by a thiol group (-SH), N-oxide compounds of quinoline rings in which at least one hydrogen atom in the quinoline ring is substituted by a thiol group (-SH), and salts thereof can be cited. Among them, from the viewpoint of improving the polishing rate, as component B2, preferably, N-oxide compounds of pyridine rings in which at least one hydrogen atom in the pyridine ring is substituted by a thiol group (-SH) or salts thereof.

[0057] Specific examples of Component B2 include 2-thiopyridine N-oxide and the like.

[0058] <Nitrogen-containing heteroaromatic ring compound (component B3)>

[0059] In another embodiment, the component B contained in the polishing liquid composition of the present invention is a compound or a salt thereof (component B3) containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group. Examples of the above-mentioned salt include organic amine salts such as alkali metal salts, alkaline earth metal salts, and ethanolamine salts, and ammonium salts. Component B3 can be used alone or in combination of two or more.

[0060] Therefore, the present invention, in another embodiment, relates to a polishing liquid composition, which contains abrasive (component A), a nitrogen-containing heteroaromatic ring compound (component B3), and an aqueous medium, wherein component B3 is a compound or a salt thereof containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group.

[0061] In this embodiment, as the nitrogen-containing heteroaromatic ring contained in component B3, in one or more embodiments, a monocyclic or bicyclic condensed ring can be cited. As the number of nitrogen atoms in the nitrogen-containing heteroaromatic ring contained in component B3, in one or more embodiments, 1 to 3 can be cited, and from the viewpoint of increasing the polishing rate, 1 or 2 are preferably used, and 1 is more preferably used. Regarding the nitrogen-containing heteroaromatic ring skeleton contained in component B3, from the viewpoint of increasing the polishing rate, it is preferred that a hydroxyl group is a substituent of the nitrogen atom of the nitrogen-containing heteroaromatic ring, and the nitrogen-containing heteroaromatic ring has at least one carbonyl group.

[0062] As the nitrogen-containing heteroaromatic ring skeleton contained in component B3, in one or more embodiments, at least one selected from 1-hydroxypyridine skeleton, 1-hydroxyquinoline skeleton, etc. can be cited. In the present invention, the so-called 1-hydroxypyridine skeleton refers to a structure in which the nitrogen atom contained in the pyridine ring has a hydroxyl group. The so-called 1-hydroxyquinoline skeleton refers to a structure in which the nitrogen atom contained in the quinoline ring has a hydroxyl group.

[0063] As component B3, in one or more embodiments, at least one selected from a compound in which a hydroxyl group is a substituent of a nitrogen atom of a pyridine ring, a compound in which a hydroxyl group is a substituent of a nitrogen atom of a quinoline ring, and salts thereof can be cited. Among them, from the viewpoint of improving the polishing rate, as component B3, a compound or a salt thereof in which a nitrogen-containing heteroaromatic ring has at least one carbonyl group is preferred.

[0064] In one or more embodiments, component B3 may include a compound represented by the following formula (I) or a salt thereof.

[0065] [Chemistry 1]

[0066]

[0067] In the above formula (I), R 1 R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and preferably a hydrocarbon group having 1 to 10 carbon atoms from the viewpoint of increasing the polishing rate. 1 The hydrocarbon group may be in any form of straight chain, branched chain or cyclic. 1 The carbon number of R is 1 or more and 10 or less, preferably 3 or more and 10 or less, more preferably 4 or more and 8 or less, and further preferably 5 or more and 7 or less. 1 From the viewpoint of increasing the polishing rate, a cyclic or branched hydrocarbon group having 3 to 10 carbon atoms is preferred, and specific examples thereof include a cyclohexyl group and a 2,4,4-trimethylpentyl group.

[0068] In the above formula (I), R 2It is a hydrocarbon group having 1 to 6 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms from the viewpoint of increasing the polishing rate, and specific examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0069] As the compound represented by the above formula (I), from the viewpoint of increasing the polishing rate, R in the formula (I) is preferably 1 is a cyclic or branched hydrocarbon group having 3 or more and 10 or less carbon atoms, R 2 is a methyl compound, more preferably R in formula (I) 1 is cyclohexyl or 2,4,4-trimethylpentyl, R 2 The compound is a methyl compound, and further preferably R in formula (I) 1 For cyclohexyl, R 2 A compound containing methyl.

[0070] As component B3, for example, at least one selected from ciclopirox, piroctone, and their salts can be cited. As specific examples of component B3, ciclopirox olamine (6-cyclohexyl-1-hydroxy-4-methyl-2 (1H)-pyridone ethanolamine salt), piroctone olamine (1-hydroxy-4-methyl-6- (2,4,4-trimethylpentyl) -2 (1H)-pyridone ethanolamine salt) and the like can be cited.

[0071] About the content of component B in the polishing liquid composition of the present invention, in one or more embodiments, when the total content of component A, component B, and aqueous medium is set to 100 mass %, with respect to the viewpoint of improving polishing speed, preferably more than 0.001 mass %, more preferably more than 0.005 mass %, more preferably more than 0.01 mass %, more preferably more than 0.02 mass %, and, with respect to the same viewpoint, preferably less than 1 mass %, more preferably less than 0.5 mass %, more preferably less than 0.1 mass %, more preferably less than 0.06 mass %. More specifically, the content of component B is preferably more than 0.001 mass % and less than 1 mass %, more preferably more than 0.005 mass % and less than 0.5 mass %, more preferably more than 0.01 mass % and less than 0.1 mass %, more preferably more than 0.02 mass % and less than 0.06 mass %. In the case where component B is a combination of more than 2 kinds, the content of component B refers to their total content.

[0072] About the content of component B in the polishing liquid composition of the present invention, in one or more other embodiments, when the total content of component A, component B, and aqueous medium is set to 100 mass %, with respect to the viewpoint of improving polishing speed, preferably more than 0.0001 mass %, more preferably more than 0.001 mass %, more preferably more than 0.006 mass %, more preferably more than 0.01 mass %, and, with respect to the same viewpoint, preferably less than 1 mass %, more preferably less than 0.5 mass %, more preferably less than 0.1 mass %, more preferably less than 0.06 mass %. More specifically, the content of component B is preferably more than 0.0001 mass % and less than 1 mass %, more preferably more than 0.001 mass % and less than 0.5 mass %, more preferably more than 0.006 mass % and less than 0.1 mass %, more preferably more than 0.01 mass % and less than 0.06 mass %. In the case where component B is a combination of more than 2 kinds, the content of component B refers to their total content.

[0073] Regarding the mass ratio A / B (content of component A / content of component B) of component A to component B in the polishing composition of the present invention, in one or more embodiments, from the viewpoint of improving the polishing rate, it is preferably 0.001 or more, more preferably 0.1 or more, further preferably 0.7 or more, further preferably 1.6 or more, and preferably 6000 or less, more preferably 200 or less, further preferably 70 or less, further preferably 25 or less. More specifically, the mass ratio A / B is preferably 0.001 or more and 6000 or less, more preferably 0.1 or more and 200 or less, further preferably 0.7 or more and 70 or less, further preferably 1.6 or more and 25 or less.

[0074] Regarding the mass ratio A / B (content of component A / content of component B) of component A to component B in the polishing liquid composition of the present invention, in one or more other embodiments, from the viewpoint of improving the polishing rate, it is preferably 0.001 or more, more preferably 0.1 or more, further preferably 0.7 or more, and further preferably 1.6 or more, and is preferably 6000 or less, more preferably 1000 or less, further preferably 200 or less, and further preferably 100 or less. More specifically, the mass ratio A / B is preferably 0.001 or more and 6000 or less, more preferably 0.1 or more and 1000 or less, further preferably 0.7 or more and 200 or less, and further preferably 1.6 or more and 100 or less.

[0075] [Water-based media]

[0076] As the aqueous medium contained in the polishing liquid composition of the present invention, it is possible to enumerate: water such as distilled water, ion exchange water, pure water and ultrapure water, or a mixed solvent of water and a solvent, etc. As the above-mentioned solvent, it is possible to enumerate a solvent that can be mixed with water (for example, alcohols such as ethanol). In the case where the aqueous medium is a mixed solvent of water and a solvent, the ratio of water to all mixed media can be unrestricted if it does not hinder the effect of the present invention. From the perspective of economy, for example, it is preferably more than 95% by mass, more preferably more than 98% by mass, and more preferably substantially 100% by mass. From the perspective of the surface cleanliness of the polished substrate, as an aqueous medium, it is preferred that water, more preferably ion exchange water and ultrapure water, further preferably ultrapure water. The content of the aqueous medium in the polishing liquid composition of the present invention can be the surplus except component A, component B and the optional component described later coordinated as required.

[0077] [Optional Ingredients]

[0078] The polishing liquid composition of the present invention may further contain any component such as a pH adjuster, a surfactant, a thickener, a dispersant, a rust inhibitor, a preservative, an alkaline substance, a polishing speed enhancer, a silicon nitride film polishing inhibitor, a polysilicon film polishing inhibitor, and a counterion. In the case where the polishing liquid composition of the present invention further contains any component, from the perspective of improving the polishing speed, the content of any component in the polishing liquid composition of the present invention is preferably 0.001 mass % or more, more preferably 0.0025 mass % or more, more preferably 0.01 mass % or more, and preferably 1 mass % or less, more preferably 0.5 mass % or less, and more preferably 0.1 mass % or less. More specifically, the content of any component is preferably 0.001 mass % or more and 1 mass % or less, more preferably 0.0025 mass % or more and 0.5 mass % or less, and more preferably 0.01 mass % or more and 0.1 mass % or less.

[0079] [Polishing liquid composition]

[0080] The polishing liquid composition of the present invention can be manufactured, for example, by a manufacturing method including the following steps: a step of mixing component A, component B and an aqueous medium, and any of the above-mentioned components as required, using a known method. For example, the polishing liquid composition of the present invention can be a polishing liquid composition formed by mixing at least component A, component B and an aqueous medium. In the case where component A is a combination of multiple cerium dioxide particles, component A can be obtained by mixing multiple cerium dioxide particles respectively. In the case where component B is a combination of multiple N-oxide compounds, component B can be obtained by mixing multiple N-oxide compounds respectively. In the case where component B is a combination of multiple nitrogen-containing heteroaromatic ring compounds, component B can be obtained by mixing multiple nitrogen-containing heteroaromatic ring compounds respectively. In the present invention, the so-called "matching" includes mixing component A, component B and an aqueous medium, and any of the above-mentioned components as required, simultaneously or sequentially. The order of mixing is not particularly limited. The above-mentioned matching can be carried out, for example, using a mixer such as a homogenizer, a homogenizer, an ultrasonic disperser and a wet ball mill. The amount of each component blended in the method for producing a polishing composition of the present invention can be the same as the content of each component in the polishing composition of the present invention described above.

[0081] The embodiment of the polishing liquid composition of the present invention can be a so-called 1-liquid type supplied to the market in a state where all components are mixed in advance, or a so-called 2-liquid type mixed when used. As an embodiment of the 2-liquid type polishing liquid composition, there can be cited a polishing liquid composition 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 when used. The mixing of the first liquid and the second liquid can be carried out before supplying to the surface of the polishing object, or they can be supplied separately and mixed on the surface of the polished substrate. The first liquid and the second liquid can contain the above-mentioned arbitrary components as required.

[0082] The pH value of the polishing composition of the present invention is preferably 3.5 or more, more preferably 4 or more, and further preferably 4.5 or more, from the viewpoint of improving the polishing rate, and is preferably 9 or less, more preferably 8.5 or less, further preferably 8 or less, further preferably less than 8, further preferably 7 or less, and further preferably 6 or less. More specifically, the pH value is preferably 3.5 or more and 9 or less, more preferably 4 or more and 8.5 or less, further preferably 4.5 or more and 8 or less, further preferably 4.5 or more and less than 8, further preferably 4.5 or more and 7 or less, further preferably 4.5 or more and 6 or less. In the present invention, the pH value of the polishing composition is a value at 25° C. and can be measured using a pH meter. Specifically, it can be measured by the method described in the Examples.

[0083] In the present invention, the so-called "content of each component in the polishing liquid composition" refers to the content of each component at the time of polishing, that is, the moment when the polishing liquid composition starts to be used for polishing. The polishing liquid composition of the present invention can be stored and supplied in a concentrated state within the range that does not damage its stability. In this case, it is preferred in terms of reducing manufacturing and transportation costs. And the concentrated solution can be appropriately diluted with water as needed and used in the polishing process. As a dilution ratio, it is preferably 5 to 100 times.

[0084] [Film to be polished]

[0085] As the film to be polished using the polishing liquid composition of the present invention, for example, a silicon oxide film can be cited. Therefore, the polishing liquid composition of the present invention can be used for the process in which the silicon oxide film needs to be polished. That is, in one or more embodiments, the polishing liquid composition of the present invention is a polishing liquid composition (silicon oxide film polishing liquid composition) for polishing the silicon oxide film. In one or more embodiments, the polishing liquid composition of the present invention can be suitably used for the following polishing: polishing of the silicon oxide film performed in the process of forming the element separation structure of the semiconductor substrate, polishing of the silicon oxide film performed in the process of forming the interlayer insulating film, polishing of the silicon oxide film performed in the process of forming the embedded metal wiring, or polishing of the silicon oxide film performed in the process of forming the embedded capacitor. In one or more other embodiments, the polishing liquid composition of the present invention can be suitably used in the manufacture of three-dimensional semiconductor devices such as three-dimensional NAND flash memory.

[0086] [Polishing fluid set]

[0087] In another embodiment, the present invention relates to a kit for producing the polishing composition of the present invention (hereinafter also referred to as “the polishing kit of the present invention”).

[0088] As one embodiment of the polishing liquid set of the present invention, for example, there can be cited a polishing liquid set (two-liquid polishing liquid composition) that includes an abrasive dispersion containing component A and an aqueous medium and an additive aqueous solution containing component B in a state that is not mixed with each other. The abrasive dispersion and the additive aqueous solution are mixed when used and diluted with an aqueous medium as needed. The aqueous medium contained in the abrasive dispersion may be the entire amount of the aqueous medium used in the preparation of the polishing liquid composition, or it may be a part. The additive aqueous solution may also contain a part of the aqueous medium used in the preparation of the polishing liquid composition. The abrasive dispersion and the additive aqueous solution may also contain the above-mentioned arbitrary components as needed.

[0089] According to the polishing liquid set of the present invention, a polishing liquid composition can be obtained which can ensure the polishing speed and improve the polishing selectivity.

[0090] [Method for manufacturing semiconductor substrate]

[0091] The present invention relates in one embodiment to a method for manufacturing a semiconductor substrate (hereinafter also referred to as "the method for manufacturing a semiconductor substrate of the present invention"), which includes a step of polishing a silicon oxide film using the polishing liquid composition of the present invention (hereinafter also referred to as "the polishing step using the polishing liquid composition of the present invention"). According to the method for manufacturing a semiconductor substrate of the present invention, the polishing speed of the silicon oxide film can be increased, so that the effect of efficiently manufacturing a semiconductor substrate with improved quality can be achieved.

[0092] As a specific example of the method for manufacturing a semiconductor substrate of the present invention, first, a silicon substrate is exposed to oxygen in an oxidation furnace to grow a silicon dioxide layer on its surface, and then, for example, a grinding stop film such as a silicon nitride (Si3N4) film or a polysilicon film is formed on the silicon dioxide layer by a CVD method (chemical vapor growth method). Next, a groove is formed by photolithography on a substrate including a silicon substrate and a grinding stop film arranged on one main surface side of the silicon substrate, for example, a substrate on which a grinding stop film is formed on a silicon dioxide layer of a silicon substrate. Then, for example, a silicon oxide (SiO2) film as a grinding film for trench filling is formed by a CVD method using silane gas and oxygen, and a grinding substrate to be ground in which the grinding stop film is covered by the grinding stop film (silicon oxide film) is obtained. By forming the silicon oxide film, the above-mentioned groove is filled with silicon oxide of the silicon oxide film, and the opposite side of the surface of the grinding stop film on the silicon substrate side is covered by the silicon oxide film. The opposite side of the surface of the silicon oxide film on the silicon substrate side formed in this way has a step difference formed corresponding to the convexity and concavity of the lower layer. Next, the silicon oxide film is polished by the CMP method until at least the opposite side of the surface of the silicon substrate side of the polishing stop film is exposed, and the silicon oxide film is more preferably polished until the surface of the silicon oxide film and the surface of the polishing stop film are in the same plane. The polishing liquid composition of the present invention can be used for the process of polishing by the CMP method. The width of the convex portion of the silicon oxide film corresponding to the concave and convex portion of the lower layer is, for example, 0.5 μm or more and 5000 μm or less, and the width of the concave portion is, for example, 0.5 μm or more and 5000 μm or less.

[0093] In polishing by the CMP method, the surface of the substrate to be polished is brought into contact with the polishing pad, and a polishing liquid composition is supplied to the contact portion thereof while the substrate to be polished and the polishing pad are relatively moved, thereby flattening the surface irregularities of the substrate to be polished.

[0094] It should be noted that in the manufacturing method of the semiconductor substrate of the present invention, other insulating films may be formed between the silicon dioxide layer of the silicon substrate and the grinding stop film, and other insulating films may be formed between the film to be ground (for example, a silicon oxide film) and the grinding stop film (for example, a silicon nitride film).

[0095] In the polishing process using the polishing composition of the present invention, the rotation speed of the polishing pad can be set to, for example, 30 to 200 r / min, the rotation speed of the substrate to be polished can be set to, for example, 30 to 200 r / min, and the polishing load set for the polishing device equipped with the polishing pad can be set to, for example, 20 to 500 g / cm 2 The supply rate of the polishing liquid composition can be set to, for example, 10 to 500 mL / min or less. When the polishing liquid composition is a two-liquid polishing liquid composition, the polishing speeds of the polished film and the polishing stop film, and the polishing speed ratio (polishing selectivity) of the polished film and the polishing stop film can be adjusted by adjusting the supply rates (or supply amounts) of the first liquid and the second liquid.

[0096] In the polishing step using the polishing composition of the present invention, from the viewpoint of improving productivity, 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.

[0097] [Grinding method]

[0098] The present invention relates to a polishing method (hereinafter also referred to as the polishing method of the present invention) in one embodiment, which includes a step of polishing a film to be polished using the polishing liquid composition of the present invention. By using the polishing method of the present invention, the polishing speed of the silicon oxide film can be increased, thereby achieving an effect of improving the productivity of the semiconductor substrate with improved quality. The specific polishing method and conditions may be the same as those of the above-mentioned method for manufacturing a semiconductor substrate of the present invention.

[0099] Example

[0100] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

[0101] 1. Determination methods of various parameters

[0102] (1) pH value of polishing liquid composition

[0103] The pH value of the polishing liquid composition at 25° C. is a value measured using a pH meter (manufactured by Toa Denpa Kogyo Co., Ltd., “HM-30G”), and is a value obtained after the electrode of the pH meter is immersed in the polishing liquid composition for 1 minute.

[0104] (2) Average primary particle size of cerium dioxide particles (component A)

[0105] The average primary particle size (nm) of the cerium dioxide particles (component A) was calculated using the specific surface area S (nm) obtained by the following BET (nitrogen adsorption) method. 2 / g), and the true density of the cerium dioxide particles was set to 7.2 g / cm 3 And calculate.

[0106] (3) BET specific surface area of ​​cerium dioxide particles (component A)

[0107] The specific surface area was obtained by hot-air drying the cerium dioxide dispersion at 120° C. for 3 hours and then finely crushing it using an agate mortar. Immediately before the measurement, the sample was dried at 120° C. for 15 minutes and then measured using a specific surface area measuring device (Micromeritics automatic specific surface area measuring device "Flowsorb III2305", manufactured by Shimadzu Corporation) by a nitrogen adsorption method (BET method).

[0108] (4) Reduction potential and oxidation potential

[0109] 1) An aqueous sodium sulfate solution serving as a supporting electrolyte was prepared using ultrapure water so as to have a concentration of 0.1 mol / L, and nitrogen substitution was performed for 3 hours or more.

[0110] 2) Weigh 9.9 mL of sodium sulfate aqueous solution into a glass sample bottle (20 mL).

[0111] 3) For the surface of the glassy carbon (glassy carbon) working electrode, use a 1 μm diamond and diamond polishing pad (both manufactured by BAS) to press the electrode vertically and polish it in the shape of a figure 8. Then, use 0.05 μm alumina and alumina polishing pad (both manufactured by BAS) to polish it in the shape of a figure 8 until the electrode surface becomes a mirror surface. Thereafter, the electrode surface is cleaned with ultrapure water and dried.

[0112] 4) A glassy carbon electrode, a silver / silver chloride reference electrode, and a platinum counter electrode were connected to an ALS electrochemical analyzer (model 611D) and immersed in a sodium sulfate aqueous solution to form a three-electrode electrochemical unit.

[0113] 5) The cyclic voltammetry variables were set to high potential 1 V, low potential 1 V, scan rate 0.1 V / s, scan number 5w, and the potential-current data points were displayed on the monitor.

[0114] 6) The glass sample bottle is fully purged with nitrogen through a Teflon (registered trademark) tube, and then measurement is performed using only the supporting electrolyte. If nitrogen purging is insufficient at this time, a peak derived from dissolved oxygen will be detected.

[0115] 7) A measurement sample (additive: 1000 ppm) was prepared using ultrapure water, and the atmosphere was fully replaced with nitrogen. Thereafter, 0.1 mL of the measurement sample was added to 9.9 mL of an aqueous sodium sulfate solution in a glass sample bottle to obtain a 10 ppm aqueous solution of the additive.

[0116] 8) Measure the open circuit potential and set it as the initial potential of the cyclic voltammetry variable to perform the measurement. At this time, confirm that no peak derived from dissolved oxygen is detected, and confirm the redox potential based on the cyclic voltammogram derived from the measurement sample.

[0117] 2. Preparation of polishing liquid composition (Examples 1 to 4 and Comparative Examples 1 to 10)

[0118] Ceria particles (component A), additives (component B or non-component B shown in Table 1) and water were mixed to obtain polishing liquid compositions of Examples 1 to 4 and Comparative Examples 1 to 10. The content of each component in the polishing liquid composition was 0.15 mass % of component A and 0.01 mass % of component B or non-component B. The content of water was the remainder excluding component A and component B or non-component B. The pH value of the polishing liquid composition of Examples 1 to 4 and Comparative Examples 1 to 10 was 5. pH adjustment was performed using ammonia or nitric acid.

[0119] The component A, component B, and non-component B used in the preparation of the polishing compositions of Examples 1 to 4 and Comparative Examples 1 to 10 are as follows.

[0120] Colloidal cerium dioxide [average primary particle size 26nm, BET specific surface area 32m 2 / g, "HC30" manufactured by SOLVAY] (ingredient A)

[0121] 2-Hydroxypyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (Component B)

[0122] 2-Mercaptopyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (Component B)

[0123] Pyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0124] 2-Hydroxypyridine (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0125] 4-Methoxypyridine N-oxide (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0126] 4-Chloropyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0127] 4-Nitropyridine N-oxide (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0128] Catechol (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0129] Ascorbic acid (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0130] Picolinic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0131] Picolinic acid-N-oxide (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0132] 3. Evaluation of polishing liquid composition (Examples 1 to 4 and Comparative Examples 1 to 10)

[0133] [Evaluation samples]

[0134] As a sample for evaluation, a commercially available wafer for CMP characteristic evaluation ("T-TEOSMIT864 PT wafer" manufactured by Advantec, with a diameter of 200 mm) was prepared and cut into 40 mm × 40 mm. For this sample for evaluation, a silicon nitride film with a film thickness of 150 nm as the first layer and a silicon oxide film with a film thickness of 450 nm as the second layer were arranged on a silicon substrate as convex parts, and a silicon oxide film with a film thickness of 450 nm was also arranged on the concave parts, and a linear concave-convex pattern was formed by etching in such a way that the step difference between the convex parts and the concave parts became 350 nm. The silicon oxide film was formed by P-TEOS, and the line widths of the convex parts and the concave parts were 100 μm and 500 μm, respectively, as the measurement objects.

[0135] [Grinding conditions]

[0136] Grinding device: Single-side grinder [TEXHNOLYZE "TR15M-TRK1", platen diameter 380 mm]

[0137] Polishing pad: Hard urethane pad [NITTA HAAS "IC-1000 / Suba400"]

[0138] Platen speed: 90rpm

[0139] Press head speed: 90rpm

[0140] Grinding load: 300g / cm 2

[0141] Polishing liquid supply: 50mL / min

[0142] Grinding time: 1 minute

[0143] [Measurement of polishing speed]

[0144] The pattern substrate was polished under the above polishing conditions using the polishing compositions of Examples 1 to 4 and Comparative Examples 1 to 10. After polishing, the sample was washed with ultrapure water and dried, and the sample was used as a measurement object by an optical interference film thickness measuring device described below.

[0145] Before and after polishing, the film thickness of the silicon oxide film was measured using an optical interference film thickness measuring device ("VM-1230" manufactured by SCREEN Semiconductor Solutions). The polishing rate of the silicon oxide film was calculated by the following formula. The calculated results are shown in Table 1. In addition, the relative values ​​of Comparative Example 10 set to 1.0 are also shown in Table 1.

[0146] Polishing speed of silicon oxide film (nm / min)

[0147] = [Thickness of silicon oxide film before polishing (nm) - Thickness of silicon oxide film after polishing (nm)] / Polishing time (minutes)

[0148] [Table 1]

[0149]

[0150] The present invention will be further described with reference to other embodiments, but the present invention is not limited thereto.

[0151] 4. Preparation of polishing liquid composition (Examples 1, 5 and Comparative Examples 1-2, 10-13)

[0152] Ceria particles (component A), an additive (component B1 or non-component B shown in Table 2) and water were mixed to obtain polishing liquid compositions of Examples 1 and 5 and Comparative Examples 1 to 2 and 10 to 13. The content of each component in the polishing liquid composition is 0.15 mass % of component A, and the content of component B1 or non-component B is as shown in Table 2. The content of water is the remainder excluding component A and component B1 or non-component B. The pH value of the polishing liquid composition of Examples 1 and 5 and Comparative Examples 1 to 2 and 10 to 13 is 5. The pH value adjustment is carried out using ammonia or nitric acid.

[0153] Component A, component B1, and non-component B used in the preparation of the polishing composition are shown below.

[0154] Colloidal cerium dioxide [average primary particle size 26nm, BET specific surface area 32m 2 / g, "HC30" manufactured by SOLVAY] (ingredient A)

[0155] Amorphous cerium dioxide [average primary particle size 19nm, BET specific surface area 44m 2 / g](ingredient A)

[0156] 2-Hydroxypyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (Component B1)

[0157] Pyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0158] 4-Hydroxypyridine (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0159] 2-Hydroxypyridine (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0160] 5. Evaluation of polishing liquid composition (Examples 1, 5 and Comparative Examples 1-2, 10-13)

[0161] [Evaluation samples]

[0162] As a sample for evaluation, a commercially available wafer for CMP characteristic evaluation ("T-TEOSMIT864 PT wafer" manufactured by Advantec, with a diameter of 200 mm) was prepared and cut into 40 mm × 40 mm. For this sample for evaluation, a silicon nitride film with a film thickness of 150 nm as the first layer and a silicon oxide film with a film thickness of 450 nm as the second layer were arranged on a silicon substrate as convex parts, and a silicon oxide film with a film thickness of 450 nm was also arranged on the concave parts, and a linear concave-convex pattern was formed by etching in such a way that the step difference between the convex parts and the concave parts became 350 nm. The silicon oxide film was formed by P-TEOS, and the line widths of the convex parts and the concave parts were 100 μm and 500 μm, respectively, as the measurement objects.

[0163] [Grinding conditions]

[0164] Grinding device: Single-side grinder [TEXHNOLYZE "TR15M-TRK1", platen diameter 380 mm]

[0165] Polishing pad: Hard urethane pad [NITTA HAAS "IC-1000 / Suba400"]

[0166] Platen speed: 90rpm

[0167] Press head speed: 90rpm

[0168] Grinding load: 300g / cm 2

[0169] Polishing liquid supply: 50mL / min

[0170] Grinding time: 1 minute

[0171] [Measurement of polishing speed]

[0172] The pattern substrate was polished under the above polishing conditions using the polishing compositions of Examples 1 and 5 and Comparative Examples 1 to 2 and 10 to 13. After polishing, the sample was washed with ultrapure water and dried, and the sample was used as a measurement object by an optical interference film thickness measuring device described below.

[0173] Before and after polishing, the film thickness of the silicon oxide film was measured using an optical interference film thickness measuring device ("VM-1230" manufactured by SCREEN Semiconductor Solutions). The polishing rate of the silicon oxide film was calculated by the following formula. The calculated results are shown in Table 2. In addition, the relative values ​​of Comparative Example 10 set to 1 are also shown in Table 2.

[0174] Polishing speed of silicon oxide film (nm / min)

[0175] = [Thickness of silicon oxide film before polishing (nm) - Thickness of silicon oxide film after polishing (nm)] / Polishing time (minutes)

[0176] [Table 2]

[0177]

[0178] As shown in Table 2, Examples 1 and 5 using Component B1 showed improved polishing rates compared to Comparative Examples 1 to 2 and 10 to 13 not using Component B1.

[0179] The present invention will be further described with reference to other embodiments, but the present invention is not limited thereto.

[0180] 6. Preparation of Polishing Liquid Composition (Examples 2, 6-7 and Comparative Examples 1, 3-5, 10-11, 13)

[0181] Ceria particles (component A), additives (component B2 or non-component B shown in Table 3) and water are mixed to obtain polishing liquid compositions of Examples 2, 6 to 7 and Comparative Examples 1, 3 to 5, 10 to 11, and 13. The content (active ingredient) of each component in the polishing liquid composition is 0.15% by mass of component A, and the content (mass %) of component B2 or non-component B is shown in Table 3. The content of water is the remainder excluding component A and component B2 or non-component B. The pH value of the polishing liquid composition of Examples 2, 6 to 7 and Comparative Examples 1, 3 to 5, 10 to 11, and 13 is 5.0. pH adjustment is carried out using ammonia or nitric acid.

[0182] Component A, component B2, and non-component B used in the preparation of the polishing composition are shown below.

[0183] Colloidal cerium dioxide [average primary particle size 26nm, BET specific surface area 32m 2 / g, "HC30" manufactured by SOLVAY] (ingredient A)

[0184] Amorphous cerium dioxide [average primary particle size 19nm, BET specific surface area 44m 2 / g](ingredient A)

[0185] 2-Mercaptopyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (Component B2)

[0186] Pyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0187] 4-Chloropyridine N-oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (not component B)

[0188] 4-Nitropyridine N-oxide (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0189] 4-Methoxypyridine N-oxide (manufactured by FUJIFILM Wako Chemical Co., Ltd.) (not component B)

[0190] 7. Evaluation of Polishing Liquid Compositions (Examples 2, 6 to 7 and Comparative Examples 1, 3 to 5, 10 to 11, 13)

[0191] [Evaluation samples]

[0192] As a sample for evaluation, a commercially available wafer for CMP characteristic evaluation ("T-TEOSMIT864 PT wafer" manufactured by Advantec, with a diameter of 200 mm) was prepared and cut into 40 mm × 40 mm. For this sample for evaluation, a silicon nitride film with a film thickness of 150 nm as the first layer and a silicon oxide film with a film thickness of 450 nm as the second layer were arranged on a silicon substrate as convex parts, and a silicon oxide film with a film thickness of 450 nm was also arranged on the concave parts, and a linear concave-convex pattern was formed by etching in such a way that the step difference between the convex parts and the concave parts became 350 nm. The silicon oxide film was formed by P-TEOS, and the line widths of the convex parts and the concave parts were 100 μm and 500 μm, respectively, as the measurement objects.

[0193] [Grinding conditions]

[0194] Grinding device: Single-side grinder [TEXHNOLYZE "TR15M-TRK1", platen diameter 380 mm]

[0195] Polishing pad: Hard urethane pad [NITTA HAAS "IC-1000 / Suba400"]

[0196] Platen speed: 90rpm

[0197] Press head speed: 90rpm

[0198] Grinding load: 300g / cm 2

[0199] Polishing liquid supply: 50mL / min

[0200] Grinding time: 1 minute

[0201] [Measurement of polishing speed]

[0202] The pattern substrate was polished under the above polishing conditions using the polishing liquid compositions of Examples 2, 6 to 7 and Comparative Examples 1, 3 to 5, 10 to 11, and 13. After polishing, the sample was washed with ultrapure water and dried, and the sample was measured by an optical interference film thickness measuring device described below.

[0203] Before and after polishing, the film thickness of the silicon oxide film was measured using an optical interference film thickness measuring device ("VM-1230" manufactured by SCREEN Semiconductor Solutions). The polishing rate of the silicon oxide film was calculated by the following formula. The calculated results are shown in Table 3. In addition, the relative values ​​of Comparative Example 10 set to 1 are also shown in Table 3.

[0204] Polishing speed of silicon oxide film (nm / min)

[0205] = [Thickness of silicon oxide film before polishing (nm) - Thickness of silicon oxide film after polishing (nm)] / Polishing time (minutes)

[0206] [Table 3]

[0207]

[0208] As shown in Table 3, Examples 2 and 6 to 7 using component B2 showed improved polishing rates for the convex portions compared to Comparative Examples 1, 3 to 5, 10 to 11, and 13 not using component B2.

[0209] The present invention will be further described with reference to other embodiments, but the present invention is not limited thereto.

[0210] 8. Preparation of Polishing Liquid Composition (Examples 3-4, 8-10 and Comparative Examples 10 and 13)

[0211] Ceria particles (component A), an additive (component B3 shown in Table 4) and water were mixed to obtain polishing liquid compositions of Examples 3 to 4, 8 to 10 and Comparative Examples 10 and 13. The content of each component in the polishing liquid composition is 0.15 mass % for component A and the content of component B3 shown in Table 4. The content of water is the remainder excluding component A and component B3. The pH value of the polishing liquid composition of Examples 3 to 4, 9 to 10 and Comparative Examples 10 and 13 is 5, and the pH value of the polishing liquid composition of Example 8 is 7. pH adjustment is performed using ammonia or nitric acid.

[0212] Component A and component B3 used in the preparation of the polishing composition are shown below.

[0213] Colloidal cerium dioxide [average primary particle size 26nm, BET specific surface area 32m 2 / g, "HC30" manufactured by SOLVAY] (ingredient A)

[0214] Amorphous cerium dioxide [average primary particle size 19nm, BET specific surface area 44m 2 / g](ingredient A)

[0215] Ciclopirox olamine (manufactured by Tokyo Chemical Industry Co., Ltd.) (ingredient B3)

[0216] Piroctone olamine (manufactured by Tokyo Chemical Industry Co., Ltd.) (ingredient B3)

[0217] 9. Evaluation of polishing liquid composition (Examples 3 to 4, 8 to 10 and Comparative Examples 10 and 13)

[0218] [Evaluation samples]

[0219] <Blanket-type substrate>

[0220] A 2000 nm thick silicon oxide film (blanket film) was formed on one side of a silicon wafer by TEOS-plasma CVD method, and the resultant was cut into 40 mm×40 mm square pieces to obtain silicon oxide film test pieces (blanket substrates).

[0221] <Pattern substrate>

[0222] As a sample for evaluation, a commercially available wafer for CMP characteristic evaluation ("T-TEOSMIT864 PT wafer" manufactured by Advantec, with a diameter of 200 mm) was prepared and cut into 40 mm × 40 mm. For this sample for evaluation, a silicon nitride film with a film thickness of 150 nm as the first layer and a silicon oxide film with a film thickness of 450 nm as the second layer were arranged on a silicon substrate as convex parts, and a silicon oxide film with a film thickness of 450 nm was also arranged on the concave parts, and a linear concave-convex pattern was formed by etching in such a way that the step difference between the convex parts and the concave parts became 350 nm. The silicon oxide film was formed by P-TEOS, and the line widths of the convex parts and the concave parts were 100 μm and 500 μm, respectively, as the measurement objects.

[0223] [Grinding conditions]

[0224] Grinding device: Single-side grinder [TEXHNOLYZE "TR15M-TRK1", platen diameter 380 mm]

[0225] Polishing pad: Hard urethane pad [NITTA HAAS "IC-1000 / Suba400"]

[0226] Platen speed: 90rpm

[0227] Press head speed: 90rpm

[0228] Grinding load: 300g / cm 2

[0229] Polishing liquid supply: 50mL / min

[0230] Grinding time: 1 minute

[0231] [Measurement of polishing speed]

[0232] The pattern substrate was polished under the above polishing conditions using the polishing compositions of Examples 3 to 4, 8 to 10 and Comparative Examples 10 and 13. After polishing, the sample was washed with ultrapure water and dried, and the sample was used as a measurement object by an optical interference film thickness measuring device described below.

[0233] Before and after polishing, the film thickness of the silicon oxide film was measured using an optical interference film thickness measuring device ("VM-1230" manufactured by SCREEN Semiconductor Solutions). The polishing rate of the silicon oxide film was calculated by the following formula. The calculated results are shown in Table 4. In addition, the relative values ​​of Comparative Example 10 set to 1.0 are also shown in Table 4.

[0234] Polishing speed of silicon oxide film (nm / min)

[0235] = [Thickness of silicon oxide film before polishing (nm) - Thickness of silicon oxide film after polishing (nm)] / Polishing time (minutes)

[0236] [Table 4]

[0237]

[0238] As shown in Table 4, in Examples 3 to 4 and 8 to 10 using the component B3, the polishing rate of the silicon oxide film was improved compared with Comparative Examples 10 and 13 not using the component B3.

[0239] [Industrial Applicability]

[0240] The polishing composition of the present invention is useful in a method for producing a semiconductor substrate for high density or high integration.

Claims

1. A polishing liquid composition for silicon oxide film, comprising cerium oxide particles (component A), an additive (component B), and an aqueous medium, wherein component B is at least one selected from the following components: An N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a hydroxyl group, or a salt thereof, namely, component B1; An N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted by a thiol group, or a salt thereof, namely, component B2; and A compound containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group, or a salt thereof, ie, Component B3.

2. The polishing liquid composition according to claim 1, wherein Regarding component B, when a 10 ppm aqueous solution of component B was measured by cyclic voltammetry using an Ag / AgCl electrode as a reference, no oxidation potential was detected.

3. The polishing liquid composition according to claim 1 or 2, wherein Component B is a reducing compound containing a heteroaromatic ring skeleton.

4. The polishing liquid composition according to claim 1 or 2, wherein Component B is an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a hydroxyl group, or a salt thereof, that is, Component B1.

5. The polishing liquid composition according to claim 4, wherein Component B1 is at least one selected from an N-oxide compound having a pyridine ring in which at least one hydrogen atom is substituted with a hydroxyl group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom is substituted with a hydroxyl group, and salts thereof.

6. The polishing liquid composition according to claim 4, wherein Component B1 is 2-hydroxypyridine N-oxide.

7. The polishing liquid composition according to claim 1 or 2, wherein Component B is an N-oxide compound containing a nitrogen-containing heteroaromatic ring skeleton in which at least one hydrogen atom is substituted with a thiol group, or a salt thereof, that is, Component B2.

8. The polishing liquid composition according to claim 7, wherein Component B2 is at least one selected from an N-oxide compound having a pyridine ring in which at least one hydrogen atom is substituted with a thiol group, an N-oxide compound having a quinoline ring in which at least one hydrogen atom is substituted with a thiol group, and salts thereof.

9. The polishing liquid composition according to claim 7, wherein Component B2 is 2-mercaptopyridine N-oxide.

10. The polishing liquid composition according to claim 1 or 2, wherein Component B is a compound containing a nitrogen-containing heteroaromatic ring skeleton having at least one hydroxyl group and at least one carbonyl group or a salt thereof, that is, Component B3.

11. The polishing liquid composition according to claim 10, wherein Component B3 is at least one selected from the group consisting of a compound in which a hydroxyl group is a substituent of a nitrogen atom of a pyridine ring, a compound in which a hydroxyl group is a substituent of a nitrogen atom of a quinoline ring, and salts thereof.

12. The polishing liquid composition according to claim 10, wherein Component B3 is a compound represented by the following formula (I) or a salt thereof, In the formula (I), R 1 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, R 2 It is a hydrocarbon group having 1 to 6 carbon atoms.

13. The polishing liquid composition according to claim 12, wherein R in formula (I) 1 is a cyclic or branched hydrocarbon group having 3 or more and 10 or less carbon atoms, R 2 It is methyl.

14. The polishing liquid composition according to claim 10, wherein Component B3 is at least one selected from ciclopirox, piroctone, and salts thereof.

15. The polishing liquid composition according to claim 10, wherein Ingredient B3 is ciclopirox olamine or piroctone olamine.

16. The polishing liquid composition according to claim 1 or 2, wherein When the total content of Component A, Component B, and the aqueous medium is 100 mass %, the content of Component B is 0.001 mass % or more and 1 mass % or less.

17. The polishing liquid composition according to claim 1 or 2, wherein When the total content of Component A, Component B, and the aqueous medium is 100 mass %, the content of Component B is 0.01 mass % or more and 0.06 mass % or less.

18. The polishing liquid composition according to claim 1 or 2, wherein When the total content of Component A, Component B, and water is 100 mass %, the content of Component A is 0.001 mass % or more and 6 mass % or less.

19. The polishing liquid composition according to claim 1 or 2, wherein When the total content of Component A, Component B, and water is 100 mass %, the content of Component A is 0.1 mass % or more and 0.5 mass % or less.

20. The polishing liquid composition according to claim 1 or 2, wherein The mass ratio A / B of component A to component B is 0.001 or more and 6000 or less.

21. The polishing liquid composition according to claim 1 or 2, wherein The mass ratio A / B of component A to component B is 1.6 or more and 25 or less.

22. The polishing liquid composition according to claim 1 or 2, wherein The pH value is 3.5 or more and 9 or less.

23. The polishing liquid composition according to claim 1 or 2, wherein The pH value is 4.5 or more and 6 or less.

24. The polishing liquid composition for silicon oxide film according to claim 1 or 2, 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 using an Ag / AgCl electrode as a reference. 25 . A method for producing a semiconductor substrate, comprising the step of polishing a film to be polished using the polishing liquid composition according to claim 1 . 26 . A polishing method comprising the step of polishing a film to be polished using the polishing liquid composition according to claim 1 .

Images