Polishing agent, additive liquid for polishing agent, polishing method, and method for producing semiconductor component

Abstract

Provided are: a polishing agent that can improve silicon nitride polishing speed; a polishing method and a semiconductor component production method using said polishing agent; and an additive liquid that is for a polishing agent and that is suitable for preparation of said polishing agent. A polishing agent according to the present invention contains abrasive grains, a first additive, a second additive, and water, wherein the first additive is an oxoacid of phosphorus, and the second additive is a nitrogen-containing compound having a carboxy group.

Description

Abrasive, additive for abrasive, polishing method, and method for manufacturing semiconductor parts

[0001] The present disclosure relates to a polishing agent, an additive liquid for a polishing agent, a polishing method, and a method for manufacturing semiconductor components.

[0002] As semiconductor integrated circuits become more highly integrated and functional, microfabrication techniques are being developed to miniaturize and increase the density of semiconductor elements. Conventionally, in the manufacture of semiconductor integrated circuit devices (hereinafter also referred to as semiconductor devices), chemical mechanical polishing (hereinafter referred to as CMP) has been used to planarize interlayer insulating films, buried wiring, etc., in order to prevent problems such as unevenness (steps) on layer surfaces exceeding the depth of focus of lithography, making it impossible to obtain sufficient resolution. As the demand for higher definition and miniaturization of elements becomes more stringent, the importance of high planarization by CMP is increasing.

[0003] As semiconductor devices become more highly functional and integrated, semiconductor manufacturing processes are becoming more diverse, and so are the materials to be polished. For example, nitride films used in SAC (self-align contact) processes, gate-open processes, and SiN hard mask polishing processes are sometimes polished. Therefore, high-speed polishing of nitride films by CMP, simultaneous polishing of nitride films and oxide films, and increasing the selectivity (polishing rate ratio) between nitride films and silicon films (polysilicon, amorphous silicon, etc.) are being considered.

[0004] For example, Patent Document 1 discloses a specific abrasive containing abrasive grains and a specific compound having a polyoxyalkylene chain, and indicates that the abrasive can polish a silicon nitride film.

[0005] Japanese Patent Application Laid-Open No. 2022-10758

[0006] The present disclosure aims to provide a polishing agent that can improve the polishing rate of silicon nitride, a polishing method and a method for manufacturing semiconductor components using the polishing agent, and an additive liquid for the polishing agent that is suitable for preparing the polishing agent.

[0007] The present disclosure includes the following aspects. [1] An abrasive comprising abrasive grains, a first additive, a second additive, and water, wherein the first additive is a phosphorus oxoacid, and the second additive is a nitrogen-containing compound having a carboxy group. [2] The abrasive according to [1], wherein the second additive is a nitrogen-containing compound having one carboxy group. [3] The abrasive according to [1] or [2], wherein the second additive is represented by the following formula (2): R １ -R ２ -COOH (2) where R １ is an amino group which may have a substituent or a nitrogen-containing heterocyclic group which may have a substituent, R ２ is a single bond, or a hydrocarbon group which may have an O or S atom between the carbon-carbon bond and which may have a substituent. [4] The abrasive according to any one of [1] to [3], wherein the second additive is an amino acid or a nitrogen-containing heterocycle having a carboxy group. [5] The abrasive according to any one of [1] to [3], wherein the number of atoms between the nitrogen atom and the carbon atom constituting the carboxy group in the second additive is 1 to 3. [6] The abrasive according to [4] or [5], wherein the nitrogen-containing heterocycle is a pyridine ring. [7] The abrasive according to any one of [1] to [6], wherein the second additive is one or more selected from the group consisting of picolinic acid, nicotinic acid, and isonicotinic acid. [8] The abrasive according to any one of [1] to [7], wherein the abrasive grains include at least one selected from the group consisting of silica particles, alumina particles, zirconia particles, cerium compound particles, titania particles, germania particles, composite particles thereof, and core-shell particles. [9] The abrasive according to any one of [1] to [8], wherein the abrasive grains contain cerium compound particles.

[10] The abrasive according to [9], wherein the cerium compound particles contain one or more metals selected from the group consisting of alkaline earth metals and lanthanoids (excluding cerium).

[11] The abrasive according to any one of [1] to

[10] , wherein the first additive is represented by the following formula (1): R １１ -[P(=O)(OH) ２ ] ｎ (1) where n is 1 or 2, and when n is 1, R１１ is a hydrogen atom or a hydroxyl group, and when n is 2, R １１ is -O- or -CR １２ R １３ - and R １２ and R １３ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group which may have a substituent.

[12] The polishing agent according to any one of [1] to

[11] , wherein the first additive is one or more selected from phosphoric acid, pyrophosphoric acid, phosphorous acid, and etidronic acid.

[13] The polishing agent according to any one of [1] to

[12] , wherein the first additive is phosphoric acid or pyrophosphoric acid.

[14] The polishing agent according to any one of [1] to

[13] , wherein the content of the abrasive grains is 0.01 mass % to 10.0 mass % relative to the total mass of the polishing agent.

[15] The polishing agent according to any one of [1] to

[14] , wherein the content of the first additive is 0.1 ppm to 10,000 ppm relative to the total mass of the polishing agent.

[16] The polishing agent according to any one of [1] to

[15] , wherein the content of the second additive is 10 ppm to 20,000 ppm relative to the total mass of the polishing agent.

[17] The abrasive according to any one of [1] to

[16] , wherein the content of the second additive is greater than the content of the first additive.

[18] The abrasive according to any one of [1] to

[17] , further comprising a polymer having an alkylene oxide chain.

[19] The abrasive according to

[18] , wherein the polymer having an alkylene oxide chain is represented by the following formula (3): R ２１ -O-(AO) ｍ１ -R ２２ (3) However, R ２１ is a hydrogen atom or a hydrocarbon group which may have a substituent and which may have an N or S atom between the carbon-carbon bond, and R ２２represents a hydrogen atom or a group containing an anionic group, AO represents an alkyleneoxy group, and m1 is an integer of 1 to 200.

[20] The polishing compound according to any one of [1] to

[19] , which has a pH of 2 to 7.

[21] The polishing compound according to any one of [1] to

[20] , which has a pH of 2 to 5.5.

[22] The polishing compound according to any one of [1] to

[21] , which is used in a chemical mechanical planarization method for silicon nitride.

[23] A polishing method in which a surface to be polished of a semiconductor substrate is brought into contact with a polishing pad while supplying an abrasive, and polishing is performed by the relative movement of the two, wherein the abrasive is the abrasive according to any one of [1] to

[22] .

[24] A method for producing semiconductor components, which comprises obtaining semiconductor components by singulating a semiconductor substrate having a surface to be polished that has been polished by the polishing method according to

[23] .

[25] An additive liquid for a polishing agent, comprising a first additive, a second additive, and water, wherein the first additive is a phosphorus oxoacid, and the second additive is a nitrogen-containing compound having a carboxy group.

[0008] The present disclosure provides a polishing agent that can improve the removal rate of silicon nitride, a polishing method and a method for manufacturing semiconductor components using the polishing agent, and an additive liquid for the polishing agent that is suitable for preparing the polishing agent.

[0009] FIG. 1 is a schematic diagram illustrating an example of a polishing apparatus.

[0010] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments, and other embodiments may fall within the scope of the present invention as long as they are consistent with the spirit of the present invention. For clarity of explanation, the following description and drawings have been simplified as appropriate. Furthermore, for the sake of explanation, the scale of each component in the drawings may differ significantly. In this disclosure, the term "surface to be polished" refers to the surface to be polished of the object to be polished, for example, the surface. The term "surface to be polished" also includes intermediate surfaces that appear on semiconductor substrates during the manufacturing process of semiconductor devices. "Silicon oxide" is primarily silicon dioxide, but is not limited to this and may include silicon oxides other than silicon dioxide. "Selectivity" refers to the polishing rate (R Ａ ) of the polishing rate (RＢ ) to the ratio (R Ａ / R Ｂ ) "(Meth)acrylic" is a general term for "methacrylic" and "acrylic", and also includes (meth)acryloyl, (meth)acrylate, etc. In this specification, "ppm" indicates mass fraction (μg / g). Furthermore, unless otherwise specified, "to" indicating a numerical range includes the numerical values ​​before and after it as the lower and upper limits.

[0011] [Polishing Agent] The polishing agent of the present disclosure contains abrasive grains, a first additive, a second additive, and water, where the first additive is a phosphorus oxoacid, and the second additive is a nitrogen-containing compound having a carboxyl group, and may further contain other components. The above-described composition of this polishing agent improves the polishing rate, particularly for silicon nitride films. Therefore, for example, the selectivity between silicon nitride films and polysilicon films is improved. Below, each component that may be contained in this polishing agent is described.

[0012] <Abrasive grains> In the present polishing agent, the abrasive grains can be appropriately selected from those used as abrasive grains for CMP. Examples of the abrasive grains include at least one selected from the group consisting of silica particles, alumina particles, zirconia particles, cerium compound particles (e.g., ceria particles, cerium hydroxide particles), titania particles, germania particles, and core-shell type particles having these as core particles. Examples of the silica particles include colloidal silica and fumed silica. Examples of the alumina particles include colloidal alumina.

[0013] The core-shell particles are composed of a core particle (e.g., silica particle, alumina particle, zirconia particle, cerium compound particle, titania particle, or germania particle) and a thin film covering the surface of the core particle. The thin film may be made of at least one oxide selected from the group consisting of silica, alumina, zirconia, ceria, titania, germania, iron oxide, manganese oxide, zinc oxide, yttrium oxide, calcium oxide, magnesium oxide, lanthanum oxide, and strontium oxide. The thin film may also be composed of a plurality of nanoparticles made of these oxides.

[0014] The particle size of the core particle is preferably 0.01 μm to 0.5 μm, more preferably 0.03 μm to 0.3 μm. The particle size of the nanoparticles is only required to be smaller than the particle size of the core particle, and is preferably 1 nm to 100 nm, more preferably 5 nm to 80 nm.

[0015] In the case of core-shell type particles, the thin film preferably contains silica, alumina, or a cerium compound, and more preferably contains ceria. The abrasive grains can be used alone or in combination of two or more types.

[0016] Among the above-mentioned abrasive grains, silica particles, alumina particles, or cerium compound particles are preferred, and cerium compound particles are more preferred, from the viewpoint of excellent polishing speed of insulating films. Examples of cerium compound particles include ceria particles and metal-doped ceria particles.

[0017] The ceria particles can be appropriately selected from known ceria particles and include, for example, ceria particles produced by the methods described in JP-A-11-12561, JP-A-2001-35818, and JP-A-2010-505735. Specific examples include ceria particles obtained by adding an alkali to an aqueous ammonia solution of cerium (IV) nitrate to produce a cerium hydroxide gel, which is then filtered, washed, and fired; ceria particles obtained by crushing high-purity cerium carbonate, then crushing and classifying it; and ceria particles obtained by chemically oxidizing a cerium (III) salt in a liquid.

[0018] Although the ceria particles may contain impurities other than ceria, the ceria content in one ceria particle is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and most preferably 100% by mass (without impurities). If the ceria content in the ceria particles is 80% by mass or more, the polishing rate for insulating films (particularly silicon oxide films) is likely to be improved.

[0019] Metal-doped ceria particles are ceria particles doped with a metal. The doping metal is preferably one or more metals selected from the group consisting of alkaline earth metals and lanthanoids (excluding cerium). Examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, barium, and radium, with strontium or barium being preferred from the viewpoint of the polishability of silicon nitride. Examples of lanthanoids include lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, with lanthanum being preferred from the viewpoint of the polishability of silicon nitride.

[0020] The content of the doped metal in the metal-doped ceria particles is preferably 0.1 to 10 mol %, more preferably 0.5 to 5 mol %, based on the total amount of the present cerium oxide containing the metal.

[0021] Metal-doped ceria particles can be produced by, for example, adding an amine or the like to an aqueous solution containing cerium nitrate and a nitrate of the doping metal (e.g., lanthanum nitrate) to form a precipitate, which can then be grown. The resulting particles may then be further subjected to mechanical treatments such as double-jet processing and ultrasonic deagglomeration to reduce coarse particles and achieve a uniform particle size.

[0022] The average particle size of the abrasive grains is preferably 0.01 μm to 0.5 μm, and more preferably 0.03 μm to 0.3 μm. If the average particle size is 0.5 μm or less, the mechanical action on the surface to be polished is reduced, thereby suppressing the occurrence of polishing flaws such as scratches on the surface to be polished. Furthermore, if the average particle size is 0.01 μm or more, aggregation of the abrasive grains is suppressed, resulting in excellent storage stability of the abrasive and an excellent polishing rate. When the selectivity between the silicon oxide film and the silicon nitride film is reduced, the average particle size of the abrasive grains is preferably 0.01 μm to 0.08 μm, and more preferably 0.01 μm to 0.06 μm.

[0023] The above particle size refers to the particle size of primary particles when the abrasive grains are dispersed in the liquid without agglomeration. The above particle size refers to the particle size of agglomerated particles (secondary particles) when the abrasive grains are aggregated in the liquid. In either case, the average particle size is measured using a particle size distribution analyzer such as a laser diffraction / scattering type, using a dispersion liquid in which the abrasive grains are dispersed in a dispersing medium such as pure water.

[0024] The lower limit of the abrasive grain content is preferably 0.01 mass%, more preferably 0.05 mass%, even more preferably 0.1 mass%, even more preferably 0.2 mass%, and particularly preferably 0.25 mass%, relative to the total mass of the abrasive. If the abrasive grain content is equal to or greater than the above lower limit, an excellent polishing rate for the surface to be polished can be obtained. On the other hand, the upper limit of the abrasive grain content is preferably 10.0 mass%, more preferably 8.0 mass%, even more preferably 5.0 mass%, particularly preferably 2.0 mass%, particularly more preferably 1.0 mass%, extremely preferably 0.8 mass%, and most preferably 0.5 mass% relative to the total mass of the abrasive. If the abrasive grain content is equal to or less than the above upper limit, aggregation of the abrasive grains can be suppressed, and an increase in the viscosity of the abrasive can be suppressed, resulting in excellent handleability. When the selectivity between the silicon oxide film and the silicon nitride film is to be reduced, the content of the abrasive grains is preferably 0.1 mass % to 0.2 mass %, more preferably 0.12 mass % to 0.18 mass %.

[0025] The content of the cerium compound particles relative to the total mass of the abrasive grains is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass. If the content of the cerium compound particles relative to the total mass of the abrasive grains is 70% by mass or more, the polishing rate, particularly for insulating films, is easily improved.

[0026] <First Additive> The polishing compound of the present invention contains a phosphorus oxoacid as a first additive. In the present disclosure, a phosphorus oxoacid refers to a compound in which a hydroxy group (—OH) and an oxo group (═O) are bonded to a phosphorus atom. The first additive is preferably a compound represented by the following formula (1): R １１ -[P(=O)(OH) ２ ] ｎ (1) where n is 1 or 2, and when n is 1, R１１ is a hydrogen atom or a hydroxyl group, and when n is 2, R １１ is -O- or -CR １２ R １３ - and R １２ and R １３ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group which may have a substituent.

[0027] R １２ and R １３ The alkyl group in the formula (I) is an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. Examples of the substituent that the alkyl group may have include a hydroxyl group and a halogen atom.

[0028] Examples of the first additive include phosphoric acid, pyrophosphoric acid, phosphorous acid, etidronic acid, etc., with phosphoric acid or pyrophosphoric acid being preferred.

[0029] The first additive may be used alone or in combination of two or more.The lower limit of the content of the first additive is preferably 0.1 ppm, more preferably 1 ppm, even more preferably 5 ppm, particularly preferably 10 ppm, and extremely preferably 20 ppm, based on the total mass of the polishing agent, from the viewpoint of improving the polishing rate of the silicon nitride film.The upper limit of the content of the first additive is preferably 10,000 ppm, more preferably 5,000 ppm, even more preferably 1,000 ppm, and particularly preferably 100 ppm, based on the total mass of the polishing agent.

[0030] <Second Additive> The polishing compound contains a nitrogen-containing compound having a carboxy group (hereinafter also referred to as "nitrogen-containing compound") as a second additive. The nitrogen atom in the nitrogen-containing compound may constitute an amino group or a nitrogen-containing heterocycle. The number of carboxy groups in the nitrogen-containing compound may be one or more, and from the viewpoint of improving the polishing rate, one to three carboxy groups are preferred, one to two are more preferred, and one is particularly preferred.

[0031] The second additive is preferably a compound represented by the following formula (2): １ -R ２ -COOH (2) where R １is an amino group which may have a substituent or a nitrogen-containing heterocyclic group which may have a substituent, R ２ is a single bond or a hydrocarbon group which may have an O or S atom between the carbon-carbon bond and which may have a substituent.

[0032] R １ The optionally substituted amino group in R ３ R ４ N-, and R ３ and R ４ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group which may have a substituent. Examples of the substituent that the phenyl group may have include an alkyl group having 1 to 6 carbon atoms and a halogen atom. R １ Examples of the nitrogen-containing heterocycle in the formula (I) include a pyrrolidine ring, a pyrroline ring, a pyrrole ring, a piperidine ring, a pyridine ring, an indole ring, an indoline ring, an isoindole ring, an isoindoline ring, a quinoline ring, an isoquinoline ring, a carbazole ring, an acridine ring, a pyrazole ring, an imidazole ring, a piperazine ring, a pyridazine ring, a pyrimidazine ring, a pyrazine ring, a triazine ring, etc. Among these, the nitrogen-containing heterocycle is preferably a nitrogen-containing heterocycle having one nitrogen atom, and more preferably a pyridine ring.

[0033] R ２ The hydrocarbon group in the formula (I) is an alkylene group having 1 to 6 carbon atoms which may have a substituent, and more preferably an alkylene group having 1 to 3 carbon atoms. Examples of the substituent which the hydrocarbon group may have include an alkyl group, a halogen atom, and each of the substituents constituting an amino acid.

[0034] In addition, in terms of improving the polishing rate, the number of atoms between the nitrogen atom and the carbon atom constituting the carboxy group in the nitrogen-containing compound is preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 5, and particularly preferably 1 to 3. When the nitrogen-containing compound has two or more nitrogen atoms and / or two or more carboxy groups, it is preferable that the number of atoms between the nearest nitrogen atom and the nearest carboxy group is within the above-mentioned range.

[0035] The nitrogen-containing compound is preferably an amino acid or a nitrogen-containing heterocycle having a carboxy group. Specific examples of amino acids include glycine, alanine, valine, leucine, isoleucine, phenylalanine, serine, threonine, histidine, and glutamine. Specific examples of nitrogen-containing heterocycles having a carboxy group include picolinic acid, nicotinic acid, and isonicotinic acid.

[0036] The second additive may be used alone or in combination of two or more.The lower limit of the content of the second additive is preferably 10 ppm, more preferably 50 ppm, even more preferably 100 ppm, particularly preferably 500 ppm, and extremely preferably 700 ppm, based on the total mass of the polishing agent, in order to improve the polishing rate of the silicon nitride film.The upper limit of the content of the first additive is preferably 20,000 ppm, more preferably 15,000 ppm, even more preferably 10,000 ppm, particularly preferably 5,000 ppm, and extremely preferably 3,000 ppm, based on the total mass of the polishing agent.

[0037] The ratio of the first additive to the second additive is not particularly limited, but from the viewpoint of improving the polishing rate of the silicon nitride film, it is preferable that the content of the second additive is greater than the content of the first additive. The mass ratio (C1 / C2) of the content C1 of the first additive to the content C2 of the second additive is preferably 0.01 to 0.99, more preferably 0.05 to 0.95.

[0038] <Water> The polishing compound contains water as a medium for dispersing abrasive grains. The type of water is not particularly limited, but it is preferable to use pure water, ultrapure water, ion-exchanged water, etc., taking into consideration the effects on other components, prevention of impurity contamination, and effects on pH, etc.

[0039] <Additives> The present abrasive may further contain other additives, such as a polymer having an alkylene oxide chain, a pH adjuster, a dispersant, an anti-aggregating agent, a lubricant, a viscosity imparting agent, a viscosity modifier, and a preservative, and may contain two or more types of additives.

[0040] (Polymer having alkylene oxide chain) The present abrasive may further contain a polymer having an alkylene oxide chain in order to improve lubricity, etc. Examples of the polymer having an alkylene oxide chain include polyalkylene glycols having a substituent, and a polymer represented by the following formula (3) is preferred. R ２１ -O-(AO) ｍ１ -R ２２ (3) However, R ２１ is a hydrogen atom or a hydrocarbon group which may have a substituent and which may have an N or S atom between the carbon-carbon bond, and R ２２ represents a hydrogen atom or a group containing an anionic group; each AO independently represents an alkyleneoxy group; and m1 represents an integer of 1 to 200.

[0041] R ２１ Examples of the hydrocarbon group in the formula (I) include an alkyl group which may have a carbon-carbon double bond or a carbon-carbon triple bond, an aryl group, and a combination thereof. The alkyl group may be linear, branched, and / or cyclic. The alkyl group is preferably a linear or branched alkyl group having 1 to 60 carbon atoms, more preferably a linear alkyl group having 1 to 30 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a butyl group, a dodecyl group, a hexadecyl group (CH ３ (CH ２ ) １５ -), octadecyl group (CH ３ (CH ２ ) １７ -) behenyl group (CH ３ (CH ２ ) ２１ -), CH ３ (CH ２ ) ７ CH=CH(CH ２ ) ８ -, ethylene group (CH ２ ═CH—), acetylene group (CH≡C—), polyacetylene group (R ２３ -(CH=CH) ｐ where p is an integer of 1 to 15, and R ２３is a hydrogen atom or a methyl group. Examples of the combination of the alkyl group and the aryl group include a phenylethenyl group, a biphenyl group, a terphenyl group, and a cumylphenyl group. The aryl group is preferably a phenyl group or a naphthyl group. Examples of the substituent that the hydrocarbon group may have include a hydroxyl group and a halogen atom.

[0042] The alkyleneoxy group in AO may be an alkyleneoxy group having 1 to 6 carbon atoms, and from the viewpoint of hydrophilicity and adsorption to a silicon surface, an ethyleneoxy group (—CH ２ CH ２ O-) or propyleneoxy group (-CH ２ CH ２ CH ２ O- or -CH ２ CH (CH ３ )O-) is preferred, and an ethyleneoxy group is more preferred. The numbers of repeating units m1 and m2 in AO may each independently be 1 to 200. From the viewpoints of hydrophilicity and adsorptivity to silicon surfaces, n is preferably 2 or more, more preferably 5 or more. On the other hand, n is sufficient when it is 200 or less, and from the viewpoints of ease of production, n is preferably 180 or less, more preferably 150 or less.

[0043] R ２２ The anionic group in the formula (I) includes a carboxy group (—COOH), a sulfo group (—SO ３ H), phosphono group (-P(=O)(OH) ２ ) and salts thereof. Examples of the salts include alkali metal salts such as sodium salts and potassium salts, and ammonium salts. The group containing an anionic group may be a group consisting of the above-mentioned anionic group alone, or may be a hydrocarbon group having the above-mentioned anionic group as a substituent. Examples of the hydrocarbon group include an alkyl group having 1 to 6 carbon atoms and a phenyl group.

[0044] When a polymer having an alkylene oxide chain is used, the content thereof can be 0.005% by mass to 2.0% by mass, preferably 0.01% by mass to 1.5% by mass, and more preferably 0.01% by mass to 0.3% by mass, based on the total mass of the polishing agent, in order to improve the polishing rate.

[0045] (pH adjuster) A pH adjuster may be contained to adjust the pH to a predetermined value. The pH adjuster may be appropriately selected from acidic compounds, basic compounds, amphoteric compounds such as amino acids, and salts thereof. However, in the present disclosure, the first additive or the second additive is not included in the pH adjuster.

[0046] Examples of acidic compounds include inorganic acids, organic acids, and salts thereof. Examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid, and ammonium salts, sodium salts, potassium salts, and the like of these may also be used. Examples of organic acids include compounds having a carboxy group, sulfo group, or phospho group as an anionic group, and ammonium salts, sodium salts, potassium salts, and the like of these.

[0047] Examples of organic acids having a carboxy group include alkyl monocarboxylic acids such as formic acid, acetic acid, and propionic acid; carboxylic acids having a heterocycle such as 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, pyrazinecarboxylic acid, 2,3-pyrazinedicarboxylic acid, 2-quinolinecarboxylic acid, pyroglutamic acid, picolinic acid, DL-pipecolic acid, 2-furancarboxylic acid, 3-furancarboxylic acid, tetrahydrofuran-2-carboxylic acid, and tetrahydrofuran-2,3,4,5-tetracarboxylic acid; and carboxylic acids having an alicyclic ring such as cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cycloheptanecarboxylic acid, and cyclohexylcarboxylic acid. Carboxylic acids having an amino group, such as alanine, glycine, glycylglycine, aminobutyric acid, N-acetylglycine, N,N-di(2-hydroxyethyl)glycine, N-(tert-butoxycarbonyl)glycine, proline, trans-4-hydroxy-L-proline, phenylalanine, sarcosine, hydantoic acid, creatine, N-[tris(hydroxymethyl)methyl]glycine, glutamic acid, and aspartic acid; carboxylic acids having a hydroxyl group, such as lactic acid, malic acid, citric acid, tartaric acid, glycolic acid, gluconic acid, salicylic acid, 2-hydroxyisobutyric acid, glyceric acid, 2,2-bis(hydroxymethyl)propionic acid, and 2,2-bis(hydroxymethyl)butyric acid; carboxylic acids having a ketone group (keto acids), such as pyruvic acid, acetoacetic acid, and levulinic acid; Dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, and phthalic acid;

[0048] Examples of basic compounds include ammonia, sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, sodium carbonate, ammonium carbonate; quaternary ammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; and amino alcohols such as monoethanolamine, diethanolamine, and triethanolamine.

[0049] The pH adjuster can be used alone or in combination of two or more. To suppress agglomeration of abrasive grains and further improve selectivity, the pH of the polishing compound is preferably 2 to 7, more preferably 2 to 5.5. The pH adjuster can be appropriately adjusted to achieve the above pH. For example, the pH adjuster can be 0.005% to 2.0% by mass, preferably 0.01% to 1.5% by mass, and more preferably 0.01% to 0.3% by mass, of the total polishing compound.

[0050] (Dispersant) The abrasive may contain a dispersant to improve the dispersibility of the abrasive grains. Examples of dispersants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants, and one or more of these can be used. Anionic surfactants are preferably polymers having a carboxy group or an ammonium carboxylate salt, and polyacrylic acid or a polyacrylate is preferred. Examples of cationic surfactants include diallyldimethylammonium chloride polymers, diallyldimethylammonium chloride-sulfur dioxide copolymers, diallyldimethylammonium chloride-acrylamide copolymers, diallyldimethylammonium chloride-maleic acid copolymers, and maleic acid-diallyldimethylammonium ethyl sulfate-sulfur dioxide copolymers. The weight-average molecular weight of the surfactant is preferably 10,000 to 100,000, from the viewpoint of polishing the surface to be polished at a higher speed.

[0051] When a dispersant is used, the content thereof is preferably 0.0001% by mass to 0.3% by mass, more preferably 0.001% by mass to 0.2% by mass, and even more preferably 0.01% by mass to 0.15% by mass, relative to the total mass of the abrasive, from the viewpoint of polishing the surface to be polished at a higher speed.

[0052] (Lubricant) The polishing compound may contain a lubricant. The lubricant is used as needed to improve the lubricity of the polishing compound and the in-plane uniformity of the polishing rate, and examples of the lubricant include water-soluble polymers such as polyethylene glycol and polyglycerin.

[0053] <Method of Preparing Abrasive> The method of preparing the present abrasive may be appropriately selected from methods that uniformly disperse or dissolve the abrasive grains, the first additive, the second additive, and each component used as needed in the water medium. For example, the present abrasive may be prepared by separately preparing a dispersion of abrasive grains and an aqueous solution containing the first additive and the second additive (also referred to as an additive for the abrasive) and mixing them. This method provides excellent storage stability and transportation convenience for the dispersion and additive for the abrasive. The present abrasive is preferably prepared by performing the above-mentioned mixing in a polishing machine immediately before use.

[0054] The present polishing agent has an excellent polishing rate for silicon oxide films and silicon nitride films, and therefore can be suitably used in chemical mechanical planarization of silicon nitride in particular.

[0055] [Abrasive Additive Liquid] The abrasive additive liquid of the present disclosure contains a first additive, a second additive, and water, where the first additive is a phosphorus oxoacid and the second additive is a nitrogen-containing compound having a carboxy group. By using this abrasive additive liquid, the abrasive can be suitably produced by the above-described method. This abrasive additive liquid contains at least the first additive, the second additive, and water, and may further contain, as necessary, a polymer having an alkylene oxide chain, a pH adjuster, an anti-agglomerating agent, a dispersant, a lubricant, a viscosity imparting agent, a viscosity modifier, a preservative, etc. Note that each of these components is as described above, and therefore a description thereof will be omitted here.

[0056] The polishing method disclosed herein is a polishing method in which a polishing surface is brought into contact with a polishing pad while an abrasive is supplied, and polishing is performed by the relative movement of the two, and is characterized in that the abrasive is used as the abrasive. This polishing method is suitable for polishing a polishing surface containing silicon nitride.

[0057] Examples of the surface to be polished include a surface of a semiconductor substrate including a surface made of a film to be polished (such as a silicon oxide film or a silicon nitride film), a blanket wafer in which a stopper film and a film to be polished are stacked on a semiconductor substrate, and a patterned wafer in which these film types are arranged in a pattern, such as a nitride film used in a SAC (self align contact) process, a gate open process, a SiN hard mask polishing process, etc. The abrasive of the present disclosure is also effective for polishing to planarize an interlayer insulating film between multilayer wiring in the manufacture of semiconductor devices.

[0058] Examples of silicon oxide films include so-called PE-TEOS films formed by plasma CVD using tetraethoxysilane (TEOS) as a raw material. Examples of silicon oxide films include so-called HDP films formed by high-density plasma CVD. Other examples include HARP films and FCVD films formed by other CVD methods, and SOD films formed by spin coating. Examples of silicon nitride films include those formed by low-pressure CVD or plasma CVD using silane or dichlorosilane and ammonia as raw materials, or those formed by ALD. Examples of polysilicon films include those formed by low-pressure CVD or plasma CVD using silane as a raw material, and then heat-treated to form polycrystalline granules.

[0059] A known polishing apparatus can be used for this polishing method. Fig. 1 is a schematic diagram showing an example of a polishing apparatus. The polishing apparatus 20 shown in Fig. 1 includes a polishing head 22 that holds a semiconductor substrate 21, a polishing platen 23, a polishing pad 24 attached to the surface of the polishing platen 23, and an abrasive supply pipe 26 that supplies an abrasive 25 to the polishing pad 24. While the abrasive 25 is supplied from the abrasive supply pipe 26, the surface to be polished of the semiconductor substrate 21 held by the polishing head 22 is brought into contact with the polishing pad 24, and the polishing head 22 and the polishing platen 23 are rotated relative to each other to perform polishing.

[0060] The polishing head 22 may move linearly as well as rotaryly. Furthermore, the polishing platen 23 and polishing pad 24 may be approximately the same size as or smaller than the semiconductor substrate 21. In this case, it is preferable to move the polishing head 22 and polishing platen 23 relative to each other so that the entire surface to be polished of the semiconductor substrate 21 can be polished. Furthermore, the polishing platen 23 and polishing pad 24 do not have to be of the type that moves rotary, and may be, for example, of the type that moves in one direction as a belt.

[0061] Although there are no particular limitations on the polishing conditions for such a polishing apparatus 20, applying a load to the polishing head 22 to press it against the polishing pad 24 can increase the polishing pressure and improve the polishing rate. The polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoints of uniformity of the polishing rate across the polished surface of the semiconductor substrate 21, flatness, and prevention of polishing defects such as scratches. The rotation speed of the polishing platen 23 and the polishing head 22 is preferably about 50 to 500 rpm. The supply amount of the abrasive 25 is appropriately adjusted depending on the composition of the abrasive, the above-mentioned polishing conditions, etc.

[0062] The polishing pad 24 can be made of a material such as nonwoven fabric, polyurethane foam, porous resin, or non-porous resin. To facilitate the supply of abrasive 25 to the polishing pad 24 or to allow a constant amount of abrasive 25 to accumulate on the polishing pad 24, the surface of the polishing pad 24 may be grooved in a grid, concentric circle, spiral, or other pattern. If necessary, a pad conditioner may be brought into contact with the surface of the polishing pad 24 to condition the surface of the polishing pad 24 while polishing.

[0063] According to this polishing method, it is possible to obtain a high selectivity between the film to be polished and the stopper film while suppressing polishing scratches, and to achieve polishing with high flatness.

[0064] [Method for Manufacturing Semiconductor Components] In the method for manufacturing semiconductor components according to this embodiment, semiconductor components are obtained by dicing a semiconductor substrate having a surface to be polished that has been polished by the polishing method described above.

[0065] The method for manufacturing a semiconductor component of the present disclosure includes a singulation step of singulating a semiconductor substrate having a polished surface polished by the polishing method. The singulation step may include, for example, dicing the semiconductor substrate (e.g., a semiconductor wafer) using a known method such as blade dicing, laser dicing, or plasma dicing to obtain semiconductor chips as semiconductor components. The method for manufacturing a semiconductor component of the present disclosure may further include a bonding step of bonding another member to the polished surface of the semiconductor chip. This step results in a semiconductor component as a bonded assembly. Examples of the other member include a second semiconductor chip, a rewiring layer, etc. The second semiconductor chip may be a semiconductor chip obtained by the manufacturing method of the present disclosure, or may be a semiconductor chip obtained by another method. The bonding step may include, for example, placing another member directly on the polished surface and bonding it directly by fusion bonding, surface activated bonding, or the like, or bonding the polished surface to the other member via an adhesive layer. Examples of the adhesive layer include a metal layer such as solder or copper, a glass layer, or a resin layer such as polyimide or epoxy. The present disclosure can further provide an electronic device including at least one semiconductor component having a surface polished by the polishing method of the present disclosure.

[0066] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Examples 1 to 13 are examples, and Examples 14 to 17 are comparative examples.

[0067] [Measurement Method] <pH> The pH was measured using a pH meter HM-30R manufactured by DKK-TOA Corporation, with the temperature set to 25±5°C.

[0068] <Average Particle Diameter> The average particle diameter was measured using a laser scattering / diffraction particle size distribution measuring device (manufactured by Horiba, Ltd., device name: LA-950).

[0069] [Preparation of Abrasives] The first additive, the second additive, and, if necessary, a polymer having an alkylene oxide chain, shown in Table 1, were mixed with water to prepare an additive liquid for an abrasive. The resulting mixture was then mixed with an abrasive dispersion to prepare the abrasives according to Examples 1 to 17 shown in Table 1. The polymers having an alkylene oxide chain were as follows: Polymer A: Polyoxyethylene behenyl ether Polymer B: Polyoxyethylene cumyl phenyl ether sulfate

[0070] [Polishing Evaluation] <Polishing Conditions> The performance of the abrasives in each of the above examples was evaluated using a fully automatic CMP device FREX300X (manufactured by Ebara Corporation). In the evaluation, a two-layer pad (manufactured by Rodel IC-1570) was used as the polishing pad, and a diamond pad conditioner (manufactured by 3M, product name: A165) was used for conditioning the polishing pad. The polishing conditions were a polishing pressure of 14 kPa, a polishing platen rotation speed of 100 rpm, and a polishing head rotation speed of 102 rpm. The supply rate of the abrasive was 250 ml / min unless otherwise specified.

[0071] The following were used as the objects to be polished (workpieces to be polished): - A blanket wafer with a silicon dioxide film, in which a silicon dioxide film was formed on a 12-inch silicon substrate by plasma CVD using tetraethoxysilane as a raw material - A blanket wafer with a silicon nitride film, in which a silicon nitride film was formed on a 12-inch silicon substrate by low-pressure CVD using silane and ammonia as raw materials - A blanket wafer with a polysilicon film, obtained by forming a film on a 12-inch silicon substrate by low-pressure CVD using silane as a raw material, and then heat-treating it at 600°C

[0072] <Evaluation Method> A film thickness meter VM-3210 manufactured by SCREEN was used to measure the film thickness of the formed silicon dioxide film, silicon nitride film, and polysilicon film. The polishing rate of each silicon dioxide film, silicon nitride film, and polysilicon film was calculated by determining the difference between the film thickness of each blanket wafer before polishing and the film thickness after 1 minute of polishing. The average polishing rate (Å / min) obtained from the polishing rates at 49 points on the substrate surface was defined as the polishing rate, and the ratio of the polishing rate of the silicon dioxide film to the polishing rate of each stopper film (polishing rate of silicon dioxide film / polishing rate of silicon nitride film) was calculated as the selectivity.

[0073] <Evaluation Results> For each polishing agent in each example, the polishing rate of each blanket wafer was measured by the above-mentioned method, and the selectivity was calculated. The results are shown in Table 1. In the table, silicon oxide film is represented as "TEOS," silicon nitride film as "SiN," and polysilicon film as "polySi." In the polishing rate section, "ND" indicates that the result was not evaluated.

[0074]

[0075] [Summary of Results] As shown in Examples 14 to 17, polishing agents containing only the first additive or the second additive polished the silicon nitride film to some extent, but the polishing rate was insufficient. The polishing agents of Examples 1 to 13, which contained both the first additive and the second additive, were shown to have significantly improved polishing rates for silicon nitride films compared to Examples 14 to 17. Furthermore, the polishing agents of Examples 6, 7, 9, and 11, which used polymers having alkylene oxide chains, were shown to sufficiently suppress the polishing rate for polysilicon films.

[0076] According to the present disclosure, high-speed polishing can be achieved, for example, in CMP of a polishing target surface including a silicon nitride film. Therefore, the polishing method of the present disclosure is suitable for forming a planarizing film in the manufacture of semiconductor devices.

[0077] This application claims priority based on Japanese Patent Application No. 2024-90545, filed on June 4, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0078] 20... Polishing device, 21... Semiconductor substrate, 22... Polishing head, 23... Polishing platen, 24... Polishing pad, 25... Abrasive, 26... Abrasive supply pipe.

Claims

1. An abrasive comprising abrasive grains, a first additive, a second additive, and water, wherein the first additive is a phosphorus oxoacid, and the second additive is a nitrogen-containing compound having a carboxy group.

2. The polishing agent according to claim 1, wherein the second additive is a nitrogen-containing compound having one carboxy group.

3. The polishing agent according to claim 1, wherein the second additive is represented by the following formula (2): １ -R ２ -COOH (2) where R １ is an amino group which may have a substituent or a nitrogen-containing heterocyclic group which may have a substituent, R ２ is a single bond or a hydrocarbon group which may have an O or S atom between the carbon-carbon bond and which may have a substituent.

4. The polishing agent according to claim 1, wherein the second additive is an amino acid or a nitrogen-containing heterocycle having a carboxy group.

5. The polishing agent according to claim 1, wherein in the second additive, the number of atoms between the nitrogen atom and the carbon atom constituting the carboxy group is 1 to 3.

6. The polishing agent according to claim 4, wherein the nitrogen-containing heterocycle is a pyridine ring.

7. The polishing agent according to claim 1, wherein the second additive is one or more selected from the group consisting of picolinic acid, nicotinic acid, and isonicotinic acid.

8. The abrasive according to claim 1, wherein the abrasive grains comprise at least one selected from the group consisting of silica grains, alumina grains, zirconia grains, cerium compound grains, titania grains, germania grains, composite grains thereof, and core-shell grains.

9. The abrasive of claim 8, wherein the abrasive grains include cerium compound particles.

10. The abrasive according to claim 9, wherein the cerium compound particles contain one or more metals selected from the group consisting of alkaline earth metals and lanthanides (excluding cerium).

11. The polishing agent according to claim 1, wherein the first additive is represented by the following formula (1): １１ -[P(=O)(OH) ２ ] ｎ (1) where n is 1 or 2, and when n is 1, R １１ is a hydrogen atom or a hydroxyl group, and when n is 2, R １１ is -O- or -CR １２ R １３ - and R １２ and R １３ are each independently a hydrogen atom, a hydroxyl group, or an alkyl group which may have a substituent.

12. The polishing agent according to claim 11, wherein the first additive is one or more selected from phosphoric acid, pyrophosphoric acid, phosphorous acid, and etidronic acid.

13. The polishing agent according to claim 12, wherein the first additive is phosphoric acid or pyrophosphoric acid.

14. The abrasive according to claim 1, wherein the content of the abrasive grains is 0.01% by mass to 10.0% by mass relative to the total mass of the abrasive.

15. The abrasive according to claim 1, wherein the content of the first additive is 0.1 ppm to 10,000 ppm based on the total mass of the abrasive.

16. The abrasive according to claim 1, wherein the content of the second additive is 10 ppm to 20,000 ppm based on the total mass of the abrasive.

17. The abrasive according to claim 1, wherein the content of the second additive is greater than the content of the first additive.

18. The abrasive according to claim 1, further comprising a polymer having an alkylene oxide chain.

19. The polishing agent according to claim 18, wherein the polymer having an alkylene oxide chain is represented by the following formula (3): ２１ -O-(AO) ｍ１ -R ２２ (3) However, R ２１ is a hydrogen atom or a hydrocarbon group which may have a substituent and which may have an N or S atom between the carbon-carbon bond, and R ２２ represents a hydrogen atom or a group containing an anionic group; AO represents an alkyleneoxy group; and m1 represents an integer of 1 to 200.

20. The polishing agent according to claim 1, having a pH of 2 to 7.

21. The polishing agent according to claim 20, having a pH of 2 to 5.

5.

22. The abrasive of claim 1 for use in chemical mechanical planarization of silicon nitride.

23. A polishing method in which a polishing surface of a semiconductor substrate is brought into contact with a polishing pad while an abrasive is supplied, and polishing is performed by the relative movement of the two, wherein the abrasive is an abrasive according to any one of claims 1 to 22.

24. A method for manufacturing semiconductor components, comprising obtaining semiconductor components by dicing a semiconductor substrate having a surface to be polished by the polishing method according to claim 23 into individual pieces.

25. An additive liquid for abrasives, comprising a first additive, a second additive, and water, wherein the first additive is a phosphorus oxoacid, and the second additive is a nitrogen-containing compound having a carboxy group.

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