WO2024111174A1 - Cmp用研磨液、cmp用研磨液セット及び研磨方法 - Google Patents
Cmp用研磨液、cmp用研磨液セット及び研磨方法 Download PDFInfo
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- WO2024111174A1 WO2024111174A1 PCT/JP2023/028806 JP2023028806W WO2024111174A1 WO 2024111174 A1 WO2024111174 A1 WO 2024111174A1 JP 2023028806 W JP2023028806 W JP 2023028806W WO 2024111174 A1 WO2024111174 A1 WO 2024111174A1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1454—Abrasive powders, suspensions and pastes for polishing
- C09K3/1463—Aqueous liquid suspensions
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Definitions
- This disclosure relates to polishing fluids for CMP (chemical mechanical polishing), polishing fluid sets for CMP, polishing methods, etc.
- the CMP technique is a technique for planarizing the surface of a substrate obtained by forming a thin film on a substrate by chemical vapor deposition (CVD) or the like.
- CVD chemical vapor deposition
- planarization processing by CMP is essential to ensure the depth of focus in lithography. If the surface of the substrate is uneven, it may cause inconveniences such as making it impossible to focus in the exposure process or making it impossible to sufficiently form a fine wiring structure.
- the CMP technique is also applied to the process of forming element isolation (inter-element isolation; STI: shallow trench isolation) regions by polishing a plasma oxide film (BPSG, HDP-SiO 2 , p-TEOS, etc.) in the device manufacturing process; the process of forming an ILD film (an interlayer insulating film; an insulating film that electrically insulates metal members (wirings, etc.) in the same layer); and the process of planarizing a plug (e.g., an Al/Cu plug) after embedding a film containing silicon oxide in a metal wiring.
- a plasma oxide film BPSG, HDP-SiO 2 , p-TEOS, etc.
- CMP is usually performed using a device capable of supplying a polishing liquid onto a polishing pad.
- the surface of the substrate is then polished by pressing the substrate against the polishing pad while supplying the polishing liquid between the substrate surface and the polishing pad.
- the polishing liquid is one of the elemental technologies in CMP technology, and various polishing liquids have been developed to obtain high-performance polishing liquids (see, for example, Patent Document 1 below).
- the CMP process of the ILD film in particular requires polishing silicon oxide at a high polishing rate.
- silica-based polishing liquids polishing liquids using abrasive grains containing silica-based particles
- Patent Document 2 see, for example, Patent Document 2 below.
- silica-based polishing liquids it tends to be difficult to control polishing scratches, which are the cause of defects.
- JP 2008-288537 A Japanese Patent Application Laid-Open No. 9-316431 Japanese Patent Application Laid-Open No. 10-102038
- One aspect of the present disclosure aims to provide a CMP polishing liquid using abrasive grains having a negative zeta potential, which can achieve a high polishing rate of silicon oxide on convex portions when polishing a patterned wafer having a concave-convex pattern while achieving excellent dispersion stability of the abrasive grains.
- Another aspect of the present disclosure aims to provide a CMP polishing liquid set for obtaining the CMP polishing liquid.
- Still another aspect of the present disclosure aims to provide a polishing method using the CMP polishing liquid or the CMP polishing liquid set.
- a polishing liquid for CMP comprising an abrasive grain, an additive, and water, wherein the abrasive grain contains cerium-based particles, the abrasive grain has a negative zeta potential, the additive contains (A1) a 4-pyrone-based compound represented by the following general formula (1), and the pH is 5.0 or higher: [In the formula, X 11 , X 12 and X 13 each independently represent a hydrogen atom or a monovalent substituent.] [2] The polishing slurry for CMP according to [1], wherein the component (A1) contains at least one member selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone, 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and 2-ethyl-3-hydroxy-4-pyrone.
- a polishing liquid for CMP comprising an abrasive grain, an additive, and water, wherein the abrasive grain contains cerium-based particles, the abrasive grain has a negative zeta potential, the additive contains a picolinic acid compound (A2), and the pH is 5.0 or higher.
- a polishing liquid set for CMP in which components of the polishing liquid for CMP according to any one of [1] to [14] are stored separately as a first liquid and a second liquid, the first liquid containing the abrasive grains and water, and the second liquid containing at least one of the additives and water.
- a polishing method comprising a step of polishing a surface to be polished using the polishing slurry for CMP according to any one of [1] to [14].
- the polishing method according to [16] wherein the surface to be polished contains silicon oxide.
- a polishing method comprising a step of polishing a surface to be polished using a polishing liquid for CMP obtained by mixing the first liquid and the second liquid in the polishing liquid set for CMP described in [15]. [19] The polishing method according to [18], wherein the surface to be polished contains silicon oxide.
- a CMP polishing liquid using abrasive grains having a negative zeta potential, which can achieve excellent dispersion stability of the abrasive grains while achieving a high polishing rate of silicon oxide on the protruding portions when polishing a patterned wafer having a concave-convex pattern.
- a CMP polishing liquid set for obtaining the CMP polishing liquid.
- FIGS. 1A to 1C are schematic cross-sectional views showing a process of polishing an ILD film.
- the numerical range indicated using “ ⁇ ” indicates a range including the numerical values described before and after “ ⁇ ” as the minimum and maximum values, respectively.
- the numerical range “A or more” means a range exceeding A and A.
- the numerical range “A or less” means a range less than A and A.
- the upper limit or lower limit of a numerical range of a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range of another stage.
- the upper limit or lower limit of the numerical range may be replaced with a value shown in the example.
- “A or B” may include either A or B, or may include both.
- the materials exemplified in this specification may be used alone or in combination of two or more types.
- the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.
- layer and film include structures having shapes formed over the entire surface as well as structures having shapes formed only in a portion when observed in a plan view.
- process includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved.
- the polishing liquid for CMP according to this embodiment is a polishing liquid for CMP (hereinafter, sometimes simply referred to as "polishing liquid") containing abrasive grains, an additive, and water.
- the abrasive grains contain cerium-based particles (particles containing a cerium-based compound), and the zeta potential of the abrasive grains is negative.
- the additive of the polishing liquid according to the first embodiment contains (A1) a 4-pyrone-based compound (component (A1)) represented by the following general formula (1).
- the additive of the polishing liquid according to the second embodiment contains (A2) a picolinic acid compound (component (A2)).
- the additive of the polishing liquid according to this embodiment may contain component (A1) and component (A2).
- the pH of the polishing liquid according to this embodiment is 5.0 or more.
- X 11 , X 12 and X 13 each independently represent a hydrogen atom or a monovalent substituent.
- the polishing liquid according to this embodiment can achieve a high polishing rate of silicon oxide on the convex portions when polishing a patterned wafer having an uneven pattern composed of convex portions (e.g., line portions) and concave portions (e.g., space portions).
- a high polishing rate of silicon oxide on the convex portions can be achieved when polishing an area of a patterned wafer where the line/space (L/S) is 20 ⁇ m/80 ⁇ m.
- a polishing rate of silicon oxide on the convex portions in an area where L/S is 20 ⁇ m/80 ⁇ m can be achieved, for example, of 200 nm/min or more (preferably 250 nm/min or more, 300 nm/min or more, 350 nm/min or more, 400 nm/min or more, 500 nm/min or more, etc.) in the evaluation method described in the examples below.
- the polishing liquid according to this embodiment can achieve excellent dispersion stability of the abrasive grains.
- the rate of change in the average particle size of the abrasive grains after three hours can be, for example, 4% or less, as determined by the evaluation method described in the Examples below.
- the polishing liquid of this embodiment by using the (A1) component or the (A2) component together with the cerium-based particles, the interaction between the cerium-based particles and silicon oxide is easily increased (for example, the chemical reaction (reaction derived from the bond of Si-O-Ce) between the cerium-based particles in the polishing liquid and the silicon oxide of the convex portion is easily promoted), the absolute value of the negative charge of the polishing surface containing silicon oxide is reduced, and the electrostatic repulsion between the abrasive grains and the polishing surface is easily suppressed, and other effects can be obtained.
- the chemical reaction reaction derived from the bond of Si-O-Ce
- polishing a pattern wafer a polishing rate according to the pressure applied to the convex portion is easily obtained, so that a high polishing rate for silicon oxide of the convex portion can be achieved.
- the (A1) component or the (A2) component is used together with the cerium-based particles, if the pH is low, the excellent dispersion stability of the abrasive grains may not be achieved.
- the pH is 5.0 or more, so that the zeta potential of the abrasive grains is easily maintained negative within a range in which the electrostatic repulsion between the abrasive grains and the polished surface is not excessively strong, and the electrostatic repulsion between the abrasive grains is easily maintained favorably, so that the excellent dispersion stability of the abrasive grains can be achieved.
- the polishing liquid can be used to polish a patterned wafer having a concave-convex pattern to remove the convex portions, thereby planarizing the surface to be polished.
- it may be required to achieve a high polishing rate ratio of silicon oxide in the convex portions of the patterned wafer having a concave-convex pattern to silicon oxide in a blanket wafer not having a concave-convex pattern.
- L/S Line/Space
- a high polishing rate ratio of silicon oxide in the convex portion of a patterned wafer having a concave-convex pattern relative to silicon oxide in a blanket wafer not having a concave-convex pattern high flatness can be realized as a characteristic that allows selective polishing of the convex portion.
- a polishing rate of silicon oxide on a blanket wafer of, for example, 40 nm/min or more (preferably 50 nm/min or more, 80 nm/min or more, 100 nm/min or more, 150 nm/min or more, 200 nm/min or more, 300 nm/min or more, etc.).
- polishing liquid of this embodiment it is possible to obtain a sufficiently small polishing rate of silicon nitride, and a high polishing selectivity of silicon oxide to silicon nitride can be obtained. In this case, it is suitable for polishing when forming an element isolation region.
- a polishing rate of silicon nitride on a blanket wafer of, for example, 100 nm/min or less (preferably 50 nm/min or less, 30 nm/min or less, 10 nm/min or less, 5 nm/min or less, etc.).
- the polishing liquid according to this embodiment can be used in the CMP of semiconductor wafer materials, for example, to polish a silicon oxide film provided on the surface of a semiconductor wafer.
- the polishing liquid according to this embodiment can be used in the CMP process of an ILD film. According to one aspect of the polishing liquid according to this embodiment, a high polishing rate can be obtained, while suppressing the aggregation of abrasive grains and the occurrence of polishing scratches, and high flatness can be obtained.
- the abrasive grains contain cerium-based particles (particles containing a cerium-based compound).
- cerium-based particles particles containing a cerium-based compound.
- cerium-based compound of the cerium-based particles examples include cerium oxide, cerium hydroxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate.
- the cerium oxide may be CeO 2 (cerium (IV) oxide, ceria) or Ce 2 O 3 (cerium (III) oxide).
- the cerium oxide particles may contain polycrystalline cerium oxide having grain boundaries. Particles containing polycrystalline cerium oxide have the property of becoming finer during polishing and simultaneously revealing active surfaces one after another, making it possible to maintain a high polishing rate of silicon oxide on the convex parts of the pattern wafer.
- Cerium oxide particles can be produced by a calcination method or an oxidation method using hydrogen peroxide or the like. When calcining, the temperature during calcination may be 350 to 900°C. When the cerium oxide particles are aggregated, the particles may be mechanically pulverized.
- the pulverization method may be, for example, dry pulverization using a jet mill or the like, or wet pulverization using a planetary bead mill or the like.
- the jet mill may be, for example, the one described in "Chemical Engineering Journal," Vol. 6, No. 5, (1980), pp. 527-532.
- the zeta potential (surface potential) of the abrasive grains in the polishing liquid is negative (zeta potential is less than 0 mV).
- the zeta potential of the abrasive grains may be -1 mV or less, -5 mV or less, -10 mV or less, -20 mV or less, -30 mV or less, -40 mV or less, -45 mV or less, -50 mV or less, or -55 mV or less.
- the zeta potential of the abrasive grains may be -100 mV or more, -90 mV or more, -80 mV or more, -70 mV or more, -60 mV or more, -55 mV or more, -50 mV or more, or -45 mV or more.
- the zeta potential of the abrasive grains may be -100 mV or more and less than 0 mV, -80 mV or more and less than 0 mV, -60 mV or more and less than 0 mV, -100 mV to -20 mV, -80 mV to -20 mV, -60 mV to -20 mV, -100 mV to -40 mV, -80 mV to -40 mV, or -60 mV to -40 mV.
- the zeta potential of the abrasive grains can be measured, for example, using a dynamic light scattering zeta potential measuring device (for example, DelsaNano C, manufactured by Beckman Coulter, Inc.).
- the zeta potential of the abrasive grains can be adjusted using additives.
- abrasive grains having a negative zeta potential can be obtained by contacting the abrasive grains with an anionic dispersant.
- anionic dispersants include polymers having at least one selected from the group consisting of carboxy groups and carboxylate groups; ammonium dihydrogen phosphate, etc.
- polymers having at least one selected from the group consisting of carboxy groups and carboxylate groups include ammonium polyacrylate, polyacrylic acid, copolymers of acrylic acid and alkyl acrylate, copolymers of acrylic acid and methacrylic acid, salts of these, etc.
- the polishing liquid according to this embodiment may contain, as an anionic dispersant in contact with the abrasive grains, a polymer having at least one selected from the group consisting of a carboxy group and a carboxylate group, and at least one selected from the group consisting of ammonium dihydrogen phosphate, from the viewpoints of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- a polymer having at least one selected from the group consisting of a carboxy group and a carboxylate group and at least one selected from the group consisting of ammonium dihydrogen phosphate
- the average particle size of the abrasive grains may be 50 nm or more, 70 nm or more, 80 nm or more, 100 nm or more, more than 100 nm, 105 nm or more, 110 nm or more, 115 nm or more, 120 nm or more, 125 nm or more, 130 nm or more, 135 nm or more, or 140 nm or more, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, and from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer having no uneven pattern.
- the average particle size of the abrasive grains may be 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 180 nm or less, 150 nm or less, or 140 nm or less, from the viewpoint of easily suppressing the occurrence of polishing scratches. From these perspectives, the average particle size of the abrasive grains may be 50-500 nm, 50-200 nm, 50-150 nm, 70-500 nm, 70-200 nm, 70-150 nm, 100-500 nm, 100-200 nm, or 100-150 nm.
- Average particle size of abrasive grains refers to the median value of the volume distribution measured by a particle size distribution measuring device (e.g., a laser diffraction/scattering particle size measuring device) for a sample in which the abrasive grains are dispersed, and can be measured using a Microtrac MT3300EXII, a product of MicrotracBEL Corp.
- a sample is prepared by dispersing abrasive grains in water so that the content of the abrasive grains is adjusted to a range suitable for measurement, and the sample is set in the measuring device to measure the average particle size.
- a sample When measuring the particle size of abrasive grains in a polishing liquid, a sample is prepared by adjusting the content of abrasive grains in the polishing liquid so that the content of abrasive grains having a scattering intensity in a range suitable for measurement is obtained, and the sample can be used for measurement in a similar manner.
- the average particle size of the abrasive grains By adjusting the average particle size of the abrasive grains, a high polishing speed and low scratch characteristics of silicon oxide according to the particle size of the abrasive grains can be efficiently obtained.
- the content of the abrasive grains may be within the following ranges based on the total mass of the polishing liquid.
- the content of the abrasive grains may be 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.2 mass% or more, 0.3 mass% or more, 0.4 mass% or more, 0.5 mass% or more, 0.6 mass% or more, 0.8 mass% or more, 1 mass% or more, 1.2 mass% or more, 1.5 mass% or more, 1.8 mass% or more, or 2 mass% or more.
- the content of the abrasive grains may be 10 mass% or less, 5 mass% or less, 3 mass% or less, 2.5 mass% or less, 2 mass% or less, 1.8 mass% or less, 1.5 mass% or less, 1.2 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.6 mass% or less, or 0.5 mass% or less. From these perspectives, the content of the abrasive grains may be 0.01 to 10 mass%, 0.01 to 3 mass%, 0.01 to 1 mass%, 0.05 to 10 mass%, 0.05 to 3 mass%, 0.05 to 1 mass%, 0.1 to 10 mass%, 0.1 to 3 mass%, 0.1 to 1 mass%, 0.8 to 10 mass%, or 0.8 to 3 mass%.
- Component (A1) 4-pyrone compound
- the additive for the polishing liquid according to the first embodiment contains, as component (A1), a 4-pyrone compound represented by general formula (1) (hereinafter, sometimes simply referred to as a "4-pyrone compound"). It is presumed that the use of a 4-pyrone compound increases the interaction between the polishing liquid and silicon oxide, and thus tends to increase the removal rate.
- 4-pyrone compounds are compounds represented by the following general formula (1), and have a structure in which a hydroxy group is bonded to the carbon atom adjacent to the carbonyl group.
- “4-pyrone compounds” are heterocyclic compounds having a ⁇ -pyrone ring (6-membered ring) that has an oxy group and a carbonyl group, with the carbonyl group located at the 4th position relative to the oxy group.
- a hydroxy group is bonded to the carbon atom adjacent to the carboxy group in this ⁇ -pyrone ring, and the other carbon atoms may be substituted with substituents other than hydrogen atoms.
- X 11 , X 12 and X 13 are each independently a hydrogen atom or a monovalent substituent.
- the monovalent substituent include an aldehyde group, a hydroxy group, a carboxy group, a carboxylate group, a sulfonic acid group, a phosphoric acid group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, a nitro group, a hydrazine group, an alkyl group (e.g., an alkyl group having 1 to 8 carbon atoms), an aryl group (e.g., an aryl group having 6 to 12 carbon atoms), an alkenyl group (e.g., an alkenyl group having 1 to 8 carbon atoms), and the like.
- the alkyl group, the aryl group, and the alkenyl group may be substituted with OH, COOH, Br, Cl, I, NO 2 , or the like.
- X 11 , X 12 and X 13 have a monovalent substituent, the substituent may be bonded to a carbon atom adjacent to the oxy group, that is, X 11 and X 12 may be a substituent. At least two of X 11 , X 12 and X 13 may be hydrogen atoms.
- the 4-pyrone compound may contain at least one selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone (also known as 3-hydroxy-2-methyl-4H-pyran-4-one, maltol), 5-hydroxy-2-(hydroxymethyl)-4-pyrone (also known as 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one, kojic acid), and 2-ethyl-3-hydroxy-4-pyrone (also known as 2-ethyl-3-hydroxy-4H-pyran-4-one), may contain at least one selected from the group consisting of 3-hydroxy-2-methyl-4-pyrone and 5-hydroxy-2-(hydroxymethyl)-4-pyrone, and may contain 3-hydroxy-2-methyl-4-pyrone, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of a patterned wafer to silicon oxide on a blanket wafer, and easily achieving excellent dispersion stability of the abrasive grains.
- the 4-pyrone compound may be water-soluble. By using a compound that is highly soluble in water, the desired amount of additive can be dissolved well in the polishing liquid, and the effect of improving the polishing speed and the dispersion stability of the abrasive grains can be achieved at an even higher level.
- the solubility of the 4-pyrone compound in 100 g of water at room temperature (25°C) may be 0.001 g or more, 0.005 g or more, 0.01 g or more, or 0.05 g or more. There is no particular upper limit to the solubility.
- the content of the 4-pyrone compound may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the content of the 4-pyrone compound may be 0.001 mass% or more, 0.003 mass% or more, 0.005 mass% or more, 0.008 mass% or more, 0.01 mass% or more, 0.02 mass% or more, 0.03 mass% or more, 0.04 mass% or more, 0.05 mass% or more, 0.06 mass% or more, 0.08 mass% or more, 0.1 mass% or more, 0.12 mass% or more, 0.15 mass% or more, 0.18 mass% or more, or 0.2 mass% or more.
- the content of 4-pyrone compounds may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.18% by mass or less, 0.15% by mass or less, 0.12% by mass or less, 0.1% by mass or less, 0.08% by mass or less, 0.06% by mass or less, 0.05% by mass or less, 0.04% by mass or less, 0.03% by mass or less, 0.02% by mass or less, 0.01% by mass or less, less than 0.01% by mass, 0.008% by mass or less, or 0.005% by mass or less.
- the content of the 4-pyrone compound may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.1 mass%, 0.001 to 0.05 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.1 mass%, 0.01 to 0.05 mass%, 0.02 to 5 mass%, 0.02 to 1 mass%, 0.02 to 0.3 mass%, 0.02 to 0.1 mass%, or 0.02 to 0.05 mass%.
- the mass ratio A1 of the content of the 4-pyrone compound to the content of the abrasive grains (4-pyrone compound/abrasive grains) may be in the following range from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the mass ratio A1 may be 0.001 or more, 0.002 or more, 0.003 or more, 0.005 or more, 0.008 or more, 0.01 or more, 0.02 or more, 0.025 or more, 0.03 or more, 0.05 or more, 0.08 or more, 0.1 or more, 0.12 or more, 0.15 or more, 0.18 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, or 0.4 or more.
- the mass ratio A1 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.18 or less, 0.15 or less, 0.12 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.01 or less, 0.008 or less, 0.005 or less, or 0.003 or less.
- the mass ratio A1 may be 0.001 to 1, 0.001 to 0.5, 0.001 to 0.2, 0.001 to 0.1, 0.01 to 1, 0.01 to 0.5, 0.01 to 0.2, 0.01 to 0.1, 0.1 to 1, 0.1 to 0.5, or 0.1 to 0.2.
- Component (A2) Picolinic acid compound
- the additive of the polishing liquid according to the second embodiment contains a picolinic acid compound as the component (A2). It is presumed that the use of the component (A2) enhances the interaction between the polishing liquid and silicon oxide, which tends to increase the removal rate.
- the picolinic acid compound at least one selected from the group consisting of picolinic acid (a compound having a pyridine ring and a carboxyl group bonded to the 2-position of the pyridine ring) and picolinic acid derivatives can be used.
- the picolinic acid derivative may be a compound having a pyridine ring, a carboxyl group bonded to the 2-position of the pyridine ring, and a substituent bonded to a position other than the 2-position of the pyridine ring, or a compound having a pyridine ring and a carboxyl group bonded to the 2-position of the pyridine ring (the compound may have a substituent bonded to a position other than the 2-position of the pyridine ring).
- picolinic acid salt (a compound having a pyridine ring and a carboxyl group bonded to the 2-position of the pyridine ring) may be used, or a compound having a pyridine ring, a carboxyl group or a carboxyl group bonded to the 2-position of the pyridine ring, and a substituent bonded to a position other than the 2-position of the pyridine ring may be used.
- carboxyl group a functional group in which the hydrogen atom of the carboxyl group is replaced by a metal atom (sodium atom, potassium atom, etc.) may be used.
- Substituents bonded to positions other than the 2-position of the pyridine ring include a hydroxy group, an amino group, an alkyl group, a vinyl group, etc.
- the picolinic acid compound may contain at least one selected from the group consisting of picolinic acid, hydroxypicolinic acid, aminopicolinic acid, and salts thereof, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride, and may contain at least one selected from the group consisting of picolinic acid, 3-hydroxypicolinic acid, 3-aminopicolinic acid, 5-hydroxypicolinic acid, 5-aminopicolinic acid, and salts thereof.
- the picolinic acid compound may be in an embodiment containing at least one selected from the group consisting of picolinic acid and salts thereof, an embodiment containing picolinic acid, an embodiment containing at least one selected from the group consisting of hydroxypicolinic acid and salts thereof, an embodiment containing hydroxypicolinic acid, an embodiment containing at least one selected from the group consisting of aminopicolinic acid and salts thereof, or an embodiment containing aminopicolinic acid.
- the content of picolinic acid compounds the content of picolinic acid, the content of hydroxypicolinic acid, or the content of aminopicolinic acid
- the content A may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the content A may be 0.0001 mass% or more, 0.0005 mass% or more, 0.001 mass% or more, 0.003 mass% or more, 0.005 mass% or more, 0.008 mass% or more, 0.01 mass% or more, 0.02 mass% or more, 0.03 mass% or more, 0.04 mass% or more, 0.05 mass% or more, 0.055 mass% or more, 0.06 mass% or more, 0.07 mass% or more, 0.08 mass% or more, 0.09 mass% or more, or 0.1 mass% or more.
- the content A may be 5 mass% or less, 3 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.5 mass% or less, 0.4 mass% or less, 0.3 mass% or less, 0.2 mass% or less, 0.1 mass% or less, 0.09 mass% or less, 0.08 mass% or less, 0.07 mass% or less, 0.06 mass% or less, 0.055 mass% or less, 0.05 mass% or less, 0.04 mass% or less, 0.03 mass% or less, 0.02 mass% or less, 0.01 mass% or less, less than 0.01 mass%, 0.008 mass% or less, or 0.005 mass% or less.
- the content A may be 0.0001 to 5 mass%, 0.0001 to 1 mass%, 0.0001 to 0.3 mass%, 0.0001 to 0.08 mass%, 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.3 mass%, 0.001 to 0.08 mass%, 0.01 to 5 mass%, 0.01 to 1 mass%, 0.01 to 0.3 mass%, 0.01 to 0.08 mass%, 0.05 to 5 mass%, 0.05 to 1 mass%, 0.05 to 0.3 mass%, or 0.05 to 0.08 mass%.
- the mass ratio A2 may be in the following range from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, from the viewpoint of easily achieving a high polishing rate ratio of silicon oxide on the convex portions of the patterned wafer to silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- the mass ratio A2 may be 0.001 or more, 0.002 or more, 0.003 or more, 0.005 or more, 0.008 or more, 0.01 or more, 0.02 or more, 0.025 or more, 0.0275 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.08 or more, or 0.1 or more.
- the mass ratio A2 may be 1 or less, less than 1, 0.8 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.0275 or less, 0.025 or less, 0.02 or less, 0.01 or less, 0.008 or less, 0.005 or less, or 0.003 or less.
- the mass ratio A2 may be 0.001 to 1, 0.001 to 0.3, 0.001 to 0.1, 0.001 to 0.03, 0.003 to 1, 0.003 to 0.3, 0.003 to 0.1, 0.003 to 0.03, 0.01 to 1, 0.01 to 0.3, 0.01 to 0.1, or 0.01 to 0.03.
- the additive of the polishing liquid according to this embodiment may contain, as component (B), a compound having two or more nitrogen atoms bonded to a hydroxyalkyl group (nitrogen-containing hydroxyalkyl compound; excluding compounds corresponding to component (A1)).
- component (B) the interaction between the polishing liquid and the silicon oxide of the convex portions in the uneven pattern is increased, making it easier to obtain a high polishing rate for the silicon oxide of the convex portions and to suppress the polishing rate for silicon nitride that can be used as a stopper material.
- a hydroxyalkyl group is directly bonded to a nitrogen atom, and a hydroxy group is directly bonded to the alkyl group directly bonded to the nitrogen atom.
- an alkyl group having no substituent other than a hydroxy group can be used as the hydroxyalkyl group bonded to the nitrogen atom.
- the (B) component may contain a compound having a nitrogen atom to which two hydroxyalkyl groups are bonded, or may contain a compound having two or more nitrogen atoms to which two hydroxyalkyl groups are bonded, from the viewpoint of easily obtaining a high polishing rate for silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate for silicon nitride.
- the number of nitrogen atoms in one molecule of component (B) may be 2 to 5, 2 to 4, or 2 to 3, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the number of hydroxyl groups in one molecule of component (B) may be 2 to 6, 2 to 5, 2 to 4, 3 to 6, 3 to 5, 3 to 4, 4 to 6, or 4 to 5, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the (B) component may have a hydroxyalkyl group with 1 to 4, 2 to 4, 3 to 4, 1 to 3, 2 to 3, or 1 to 2 carbon atoms as the hydroxyalkyl group bonded to the nitrogen atom, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- the (B) component may have a hydroxyalkyl group with 1 to 3 or 1 to 2 hydroxy groups as the hydroxyalkyl group bonded to the nitrogen atom, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- the (B) component may have an alkylene group between two nitrogen atoms bonded to a hydroxyalkyl group, from the viewpoint of easily achieving a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride, and the number of carbon atoms in the alkylene group may be 1 to 4, 2 to 4, 1 to 3, 2 to 3, or 1 to 2.
- the (B) component may contain a compound represented by the following general formula (I) from the viewpoints of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- n is an integer of 1 or more
- R 11 , R 12 , R 13 and R 14 each independently represent a hydrogen atom or an organic group, one or both of R 11 and R 12 are hydroxyalkyl groups, and one or both of R 13 and R 14 are hydroxyalkyl groups.
- n may be within the range described above as the number of carbon atoms in the alkylene group between the two nitrogen atoms to which the hydroxyalkyl group is bonded.
- the organic group may be a substituted or unsubstituted alkyl group, a hydroxyalkyl group, or a group having a nitrogen atom to which a hydroxyalkyl group is bonded.
- substituent of the alkyl group include a hydroxy group, a carboxy group, an amino group, a sulfo group, and a nitro group.
- R 11 , R 12 , R 13 , or R 14 is a hydroxyalkyl group
- the number of carbon atoms in the hydroxyalkyl group may be within the range described above as the number of carbon atoms in the hydroxyalkyl group bonded to a nitrogen atom.
- component (B) examples include ethylene dinitrilotetraethanol (THEED: 2,2',2'',2'''-ethylene dinitrilotetraethanol (also known as N,N,N',N'-Tetrakis(2-hydroxyethyl)ethylenediamine), etc.), ethylene dinitrilotetrapropanol (EDTP: 1,1',1'',1'''-ethylene dinitrilotetra-2-propanol (also known as N,N,N',N'-Tetrakis(2-hydroxypropyl)ethylenediamine), etc.), and N,N,N',N'',N',N''-Pentakis(2-hydroxypropyl)diethylenetriamine.
- TEEED 2,2',2'',2'''-ethylene dinitrilotetraethanol
- EDTP 1,1',1'',1'''-ethylene dinitrilotetra-2-propanol
- the (B) component may contain at least one selected from the group consisting of ethylene dinitrilotetraethanol and ethylene dinitrilotetrapropanol, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride, and may contain ethylene dinitrilotetraethanol.
- the (B) component may contain a compound that does not have a carboxy group, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the molecular weight of the (B) component may be in the following ranges from the viewpoints of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the molecular weight of the (B) component may be 50 or more, 60 or more, 80 or more, 100 or more, 120 or more, 140 or more, 150 or more, 160 or more, 180 or more, 200 or more, 220 or more, or 230 or more.
- the molecular weight of the (B) component may be 1000 or less, less than 1000, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 350 or less, 300 or less, 280 or less, 250 or less, less than 250, or 240 or less. From these perspectives, the molecular weight of component (B) may be 50 to 1000, 50 to 500, 50 to 300, 50 to 250, 100 to 1000, 100 to 500, 100 to 300, 100 to 250, 200 to 1000, 200 to 500, 200 to 300, or 200 to 250.
- the content B1 of the component (B) or the content of ethylene dinitrilotetraethanol may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a pattern wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the content B1 may be 0.001% by mass or more, 0.003% by mass or more, 0.005% by mass or more, 0.008% by mass or more, or 0.009% by mass or more.
- the content B1 may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.05% by mass or less, 0.03% by mass or less, 0.01% by mass or less, or 0.009% by mass or less. From these viewpoints, the content B1 may be 0.001 to 5 mass%, 0.001 to 1 mass%, 0.001 to 0.1 mass%, 0.001 to 0.01 mass%, 0.003 to 5 mass%, 0.003 to 1 mass%, 0.003 to 0.1 mass%, 0.003 to 0.01 mass%, 0.005 to 5 mass%, 0.005 to 1 mass%, 0.005 to 0.1 mass%, or 0.005 to 0.01 mass%.
- the content B2 of the component (B) or the content of ethylene dinitrilotetraethanol may be in the following range based on the total mass of the polishing liquid, from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a pattern wafer, easily achieving high-speed polishing of silicon oxide on a blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the content B2 may be 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.015% by mass or more, 0.02% by mass or more, 0.025% by mass or more, 0.03% by mass or more, 0.035% by mass or more, 0.04% by mass or more, 0.045% by mass or more, 0.05% by mass or more, 0.055% by mass or more, 0.06% by mass or more, 0.065% by mass or more, 0.07% by mass or more, or 0.075% by mass or more.
- the content B2 may be 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, 0.09% by mass or less, 0.085% by mass or less, 0.08% by mass or less, 0.075% by mass or less, 0.07% by mass or less, 0.065% by mass or less, or 0.06% by mass or less.
- the content B2 may be 0.001 to 5% by mass, 0.001 to 1% by mass, 0.001 to 0.1% by mass, 0.01 to 5% by mass, 0.01 to 1% by mass, 0.01 to 0.1% by mass, 0.05 to 5% by mass, 0.05 to 1% by mass, or 0.05 to 0.1% by mass.
- the mass ratio B11 of the content of component (B) to the content of abrasive grains (component (B)/abrasive grains) or the mass ratio of the content of ethylene dinitrilotetraethanol to the content of abrasive grains (ethylene dinitrilotetraethanol/abrasive grains) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- Mass ratio B11 may be 0.0001 or more, 0.0005 or more, 0.001 or more, 0.002 or more, 0.003 or more, 0.004 or more, or 0.0045 or more.
- the mass ratio B11 may be 1 or less, 0.8 or less, 0.5 or less, 0.3 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.03 or less, 0.01 or less, 0.008 or less, 0.005 or less, or 0.0045 or less. From these viewpoints, the mass ratio B11 may be 0.0001 to 1, 0.0001 to 0.1, 0.0001 to 0.01, 0.001 to 1, 0.001 to 0.1, 0.001 to 0.01, 0.003 to 1, 0.003 to 0.1, or 0.003 to 0.01.
- the mass ratio B21 of the content of component (B) to the content of abrasive grains (component (B)/abrasive grains) or the mass ratio of the content of ethylene dinitrilotetraethanol to the content of abrasive grains (ethylene dinitrilotetraethanol/abrasive grains) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- Mass ratio B21 may be 0.001 or more, 0.005 or more, 0.01 or more, 0.015 or more, 0.02 or more, 0.025 or more, 0.03 or more, or 0.035 or more. Mass ratio B21 may be 1 or less, 0.5 or less, 0.3 or less, 0.1 or less, 0.08 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, or 0.03 or less. From these viewpoints, mass ratio B21 may be 0.001 to 1, 0.001 to 0.1, 0.001 to 0.05, 0.01 to 1, 0.01 to 0.1, 0.01 to 0.05, 0.03 to 1, 0.03 to 0.1, or 0.03 to 0.05.
- the mass ratio B12 of the content of the (B) component to the content of the (A1) component (component (B)/component (A1)) or the mass ratio of the content of ethylene dinitrilotetraethanol to the content of the (A1) component (ethylene dinitrilotetraethanol/component (A1)) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of the patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on the blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- the mass ratio B12 may be 0.01 or more, 0.05 or more, 0.1 or more, 0.3 or more, 0.5 or more, 0.7 or more, 0.8 or more, or 0.9 or more.
- the mass ratio B12 may be 10 or less, 8 or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2 or less, 1.5 or less, 1 or less, less than 1, or 0.9 or less. From these perspectives, the mass ratio B12 may be 0.01 to 10, 0.01 to 5, 0.01 to 1, 0.1 to 10, 0.1 to 5, 0.1 to 1, 0.5 to 10, 0.5 to 5, or 0.5 to 1.
- the mass ratio B22 of the content of the (B) component to the content of the (A2) component (component (B)/component (A2)) or the mass ratio of the content of ethylene dinitrilotetraethanol to the content of the (A2) component (ethylene dinitrilotetraethanol/component (A2)) may be in the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon oxide on the convex portions of a patterned wafer, from the viewpoint of easily achieving high-speed polishing of silicon oxide on a blanket wafer, and from the viewpoint of easily suppressing the polishing rate of silicon nitride.
- the mass ratio B22 may be 0.01 or more, 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.75 or more, 0.8 or more, 0.9 or more, 1 or more, more than 1, 1.1 or more, or 1.2 or more. Mass ratio B22 may be 10 or less, 8 or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2 or less, 1.5 or less, 1.2 or less, 1.1 or less, 1 or less, less than 1, 0.9 or less, or 0.8 or less. From these viewpoints, mass ratio B22 may be 0.01 to 10, 0.01 to 5, 0.01 to 2, 0.1 to 10, 0.1 to 5, 0.1 to 2, 0.5 to 10, 0.5 to 5, or 0.5 to 2.
- the additive of the polishing liquid according to this embodiment may further contain other components (components other than those mentioned above) according to the desired properties.
- Such components include nonionic polymers, cationic compounds, pH adjusters described below, polar solvents such as ethanol and acetone, and cyclic monocarboxylic acids.
- the polishing liquid according to this embodiment may contain a compound a having a molecular weight of 100,000 or less and 4 or more hydroxyl groups, or may not contain compound a.
- the content of compound a may be 0.01 mass% or less, less than 0.01 mass%, 0.001 mass% or less, 0.0001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid.
- the polishing liquid according to this embodiment may contain a compound b having 4 or more amino groups, or may not contain compound b.
- the content of compound b may be 0.001 mass% or less, less than 0.001 mass%, 0.0001 mass% or less, 0.00001 mass% or less, or substantially 0 mass% based on the total mass of the polishing liquid.
- the mass ratio of the content of compound a to the content of compound b (compound a/compound b) may be 0.10 or less, or less than 0.10.
- the water is not particularly limited, but may include at least one selected from the group consisting of deionized water, ion-exchanged water, and ultrapure water.
- the pH of the polishing liquid according to this embodiment is 5.0 or more from the viewpoint of achieving excellent dispersion stability of the abrasive grains.
- the zeta potential of the abrasive grains is adjusted to be negative using an anionic dispersant, if the pH is 5.0 or more, the anionic dispersant is sufficiently dissociated, and the zeta potential of the abrasive grains is likely to be maintained negative.
- the pH may be in the following range from the viewpoint of easily achieving excellent dispersion stability of the abrasive grains, easily obtaining a high polishing rate of silicon oxide on the convex parts of the patterned wafer, easily achieving high-speed polishing of silicon oxide on the blanket wafer, and easily suppressing the polishing rate of silicon nitride.
- the pH may be 12.0 or less, 11.0 or less, 10.5 or less, less than 10.5, 10.0 or less, less than 10.0, 9.5 or less, 9.0 or less, less than 9.0, 8.8 or less, 8.5 or less, 8.2 or less, 8.0 or less, less than 8.0, 7.8 or less, 7.5 or less, 7.2 or less, 7.0 or less, less than 7.0, 6.8 or less, 6.7 or less, 6.5 or less, 6.2 or less, 6.0 or less, less than 6.0, 5.7 or less, 5.5 or less, or 5.4 or less.
- the pH may be greater than 5.0, greater than 5.2, greater than 5.4, greater than 5.5, greater than 5.7, greater than 6.0, greater than 6.0, greater than 6.2, greater than 6.5, greater than 6.7, greater than 6.8, greater than 7.0, greater than 7.2, greater than 7.5, greater than 7.8, greater than 8.0, or greater than 8.2.
- the pH may be 5.0 to 12.0, 5.0 to 9.0, 5.0 to 7.5, 6.0 to 12.0, 6.0 to 9.0, 6.0 to 7.5, 6.5 to 12.0, 6.5 to 9.0, or 6.5 to 7.5.
- the pH can be measured by the method described in the Examples.
- a pH adjuster may be used to adjust the pH to the above range.
- the pH adjuster includes acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and boric acid; and bases such as sodium hydroxide, ammonia (e.g., ammonia water), potassium hydroxide, and calcium hydroxide.
- the above-mentioned additives such as component (A1), component (A2), and component (B) may be used to adjust the pH.
- the polishing liquid may be prepared without using a pH adjuster, and this polishing liquid may be applied to CMP as is.
- the polishing liquid according to this embodiment can be classified into (a) a normal type, (b) a concentrated type, and (c) a multiple liquid type (e.g., a two-liquid type, a polishing liquid set for CMP), and the preparation method and the method of use differ depending on the type.
- the normal type is a polishing liquid that can be used as is without pretreatment such as dilution during polishing.
- the concentrated type is a polishing liquid in which the components are concentrated compared to the normal type (a) in consideration of convenience in storage or transportation.
- the multiple liquid type is a polishing liquid in which the components are separated into multiple liquids (e.g., a first liquid containing a certain component and a second liquid containing another component) during storage or transportation, and these liquids are mixed when used.
- the normal type can be obtained by dissolving or dispersing abrasive grains and additives in water, which is the main dispersion medium.
- the polishing liquid can be prepared using, for example, a stirrer, homogenizer, ultrasonic disperser, wet ball mill, etc.
- the abrasive grains may be microparticulated during the preparation process of the polishing liquid so that the average grain size of the abrasive grains falls within the desired range.
- the microparticulation process of the abrasive grains can be carried out by a sedimentation classification method or a method using a high-pressure homogenizer.
- the sedimentation classification method is a method that includes a process of forcibly sedimenting a slurry containing the abrasive grains using a centrifuge and a process of extracting only the supernatant liquid.
- the method using a high-pressure homogenizer is a method in which abrasive grains in a dispersion medium are collided with each other at high pressure.
- (b) concentrated type is diluted with water immediately before use so that the content of the ingredients is the desired amount. After dilution, stirring may be carried out for any length of time until the liquid characteristics (pH, abrasive grain size, etc.) and polishing characteristics (polishing speed of silicon oxide, polishing selectivity between silicon oxide and silicon nitride, etc.) are similar to those of the (a) regular type. With such (b) concentrated type, the volume becomes smaller depending on the degree of concentration, so storage and transportation costs can be reduced.
- the concentration ratio may be 1.5 times or more, 2 times or more, 3 times or more, or 5 times or more.
- a concentration ratio of 1.5 times or more tends to provide advantages in terms of storage and transportation compared to a concentration ratio of less than 1.5 times.
- the concentration ratio may be 40 times or less, 20 times or less, or 15 times or less.
- a concentration ratio of 40 times or less tends to suppress agglomeration of the abrasive grains more easily compared to a concentration ratio of more than 40 times.
- the multiple liquid type has the advantage that, by appropriately separating each liquid (first liquid, second liquid, etc.), agglomeration of abrasive grains can be avoided compared to the concentrated type (b).
- the components contained in each liquid are arbitrary.
- the multiple liquid type (CMP polishing liquid set) is a polishing liquid set for obtaining a polishing liquid by mixing a first liquid (slurry) and a second liquid (additive liquid).
- the components of the CMP polishing liquid are stored separately as a first liquid and a second liquid, the first liquid contains abrasive grains and water, and the second liquid contains at least one type of additive and water.
- the first liquid contains abrasive grains and water
- the second liquid contains at least one type selected from the group consisting of the (A1) component and the (A2) component, and water.
- the first liquid contains abrasive grains, one of the (A1) and (A2) components, and water
- the second liquid contains the other of the (A1) and (A2) components, and water.
- the first and second liquids may contain other components that are mixed as necessary. In this case, in order to increase the dispersibility of the abrasive grains in the first liquid, any acid or alkali may be mixed into the first liquid to adjust the pH.
- a multi-liquid type polishing liquid is useful when the components are combined in a way that, when mixed, the polishing properties tend to decrease in a relatively short time due to the aggregation of abrasive grains, etc.
- at least one of the liquids may be a concentrated type.
- each liquid when using the polishing liquid, each liquid can be mixed with water.
- the concentration rate and pH of each liquid are arbitrary, and it is sufficient that the final mixture has the same liquid properties and polishing properties as the (a) normal type polishing liquid.
- the polishing method according to this embodiment includes a polishing step of polishing a surface to be polished using the polishing liquid according to this embodiment.
- the polishing liquid used in the polishing step may be a polishing liquid obtained by mixing the first liquid and the second liquid in the above-mentioned polishing liquid set. That is, the polishing method according to this embodiment may include a polishing step of polishing a surface to be polished using a polishing liquid obtained by mixing the first liquid and the second liquid in the above-mentioned polishing liquid set.
- the polishing method according to this embodiment uses a polishing solution in which the content of each component, pH, etc. are adjusted, and can planarize a substrate having a silicon oxide film on its surface by CMP technology.
- the polishing method according to this embodiment is suitable for polishing that requires high speed, high flatness, and few polishing scratches, such as polishing ILD films, and is suitable for applications in which many ILD films are polished in a short period of time. According to one aspect of the polishing method according to this embodiment, it is possible to efficiently obtain the effect of improving the polishing speed of silicon oxide on a blanket wafer and the effect of improving the in-plane uniformity.
- the polishing solution according to this embodiment since the polishing solution according to this embodiment is used, it is possible to reduce the occurrence of polishing scratches while achieving a sufficiently high polishing speed while achieving excellent dispersion stability of abrasive grains.
- the polishing process may be a process in which the polishing liquid according to this embodiment is supplied between a substrate and a polishing member (a member for polishing, such as a polishing pad), and the substrate is polished by the polishing member.
- the polishing method according to this embodiment is suitable for polishing a substrate having a silicon oxide film on its surface. Therefore, the surface to be polished may contain silicon oxide, and the polishing process may be a process in which the polishing liquid according to this embodiment is supplied between the silicon oxide film on the substrate having the silicon oxide film on its surface and the polishing member, and the silicon oxide film is polished by the polishing member.
- the polishing method according to this embodiment may be such that the surface to be polished has an uneven pattern consisting of convex portions (line portions) and concave portions (space portions), and the convex portions contain silicon oxide.
- the width of the convex portions in the uneven pattern may be 30 ⁇ m or less, or 20 ⁇ m or less.
- the width of the convex portions in the uneven pattern may be 10 ⁇ m or more, or 20 ⁇ m or more.
- the sum of the width of the convex portions and the width of the concave portions in the uneven pattern may be 200 ⁇ m or less, or 100 ⁇ m or less.
- the sum of the width of the convex portions and the width of the concave portions in the uneven pattern may be 80 ⁇ m or more, or 100 ⁇ m or more.
- the polishing method according to this embodiment is suitable for polishing a substrate having a silicon oxide film on its surface during the device manufacturing process.
- devices include discrete semiconductors such as diodes, transistors, compound semiconductors, thermistors, varistors, and thyristors; memory elements such as DRAM (dynamic random access memory), SRAM (static random access memory), EPROM (erasable programmable read only memory), mask ROM (mask read only memory), EEPROM (electrically erasable programmable read only memory), and flash memory; logical circuit elements such as microprocessors, DSPs, and ASICs; integrated circuit elements such as compound semiconductors, typified by MMICs (monolithic microwave integrated circuits); hybrid integrated circuits (hybrid ICs); light-emitting diodes; and photoelectric conversion elements such as charge-coupled devices.
- DRAM dynamic random access memory
- SRAM static random access memory
- EPROM erasable programmable read only memory
- mask ROM mask read only memory
- a high polishing rate can be achieved without being largely dependent on the uneven shape of the surface to be polished. Therefore, the polishing method using this polishing liquid can be applied to substrates for which it was difficult to achieve a high polishing rate using conventional methods using polishing liquids.
- the polishing method according to this embodiment is suitable for planarizing a polished surface having steps (unevenness) on the surface.
- An example of a substrate having such a polished surface is a semiconductor device for logic.
- the polishing method according to this embodiment is also suitable for polishing a surface including a portion in which the concave or convex portions are T-shaped or lattice-shaped when viewed from above.
- the polishing method according to this embodiment can polish at a high speed a silicon oxide film provided on the surface of a semiconductor device having memory cells (DRAM, flash memory, etc.).
- the substrate is not limited to a substrate having only a silicon oxide film on its surface, but may also have a silicon nitride film, polycrystalline silicon film, etc., on its surface in addition to a silicon oxide film.
- the substrate may also be a substrate having an inorganic insulating film such as silicon oxide, glass, silicon nitride, etc., or a film mainly containing polysilicon, Al, Cu, Ti, TiN, W, Ta, TaN, etc., on a wiring board having predetermined wiring.
- Figure 1 is a schematic cross-sectional view showing the process of polishing an ILD film, and shows the process of forming an ILD film between wirings.
- Figure 1(a) is a schematic cross-sectional view showing a substrate before polishing.
- Figure 1(b) is a schematic cross-sectional view showing the substrate after polishing.
- a wiring 20 is formed on a lower substrate (not shown) having a predetermined lower wiring (not shown) via an ILD film 10, and a silicon oxide film 30 is formed to cover this wiring 20. Since the silicon oxide film 30 is formed on the ILD film 10 on which the wiring 20 is formed, the portion above the wiring 20 is higher than the other portions, resulting in a step D on the surface of the silicon oxide film 30.
- the wiring 20 is connected to the lower wiring, etc. by a contact plug 40 formed to penetrate the ILD film 10.
- the substrate 100 is placed on a polishing member so that the surface of the silicon oxide film 30 and the polishing member come into contact with each other, and the surface of the silicon oxide film 30 is polished by the polishing member. More specifically, the surface to be polished (front surface) of the silicon oxide film 30 is pressed against the polishing member of the polishing table, and the silicon oxide film 30 is polished by moving the surface to be polished and the polishing member relative to each other while supplying a polishing liquid between them.
- This eliminates the step D and finally, as shown in FIG. 1(b), the height of the wiring 20 part on the surface of the silicon oxide film 30 becomes almost the same as the height of the other parts, and a substrate 100a having a silicon oxide film 30 (ILD film) with a flat surface is obtained.
- the polishing device used for polishing may be, for example, a device equipped with a holder for holding the substrate, a polishing platen on which a polishing pad is attached, and a means for supplying a polishing liquid onto the polishing pad.
- the polishing device include polishing devices manufactured by Ebara Corporation (model numbers: EPO-111, EPO-222, F-REX200, and F-REX300), and polishing devices manufactured by Applied Materials (product names: Mirra3400 and Reflexion).
- the material that the polishing pad is made from and examples of materials that can be used include general nonwoven fabric, polyurethane foam, and porous fluororesin.
- the polishing pad may also be grooved to allow the polishing liquid to accumulate.
- the rotation speed of the polishing platen may be 200 min ⁇ 1 or less from the viewpoint of preventing the substrate from popping out.
- the pressure (processing load) applied to the substrate may be 100 kPa or less from the viewpoint of easily suppressing polishing scratches on the surface to be polished.
- a polishing liquid may be continuously supplied to the polishing pad by a pump or the like.
- the amount of supply but the surface of the polishing pad may be constantly covered with the polishing liquid.
- the substrate may be thoroughly washed in running water, and then dried by using a spin dryer or the like to remove water droplets adhering to the substrate.
- the substrate (structure) obtained in this manner can be used as various electronic components.
- electronic components include semiconductor elements; optical glass such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, and optical waveguides made of glass and crystalline materials; end faces of optical fibers; optical single crystals such as scintillators; solid-state laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass substrates for magnetic disks; and magnetic heads.
- semiconductor elements include semiconductor elements; optical glass such as photomasks, lenses, and prisms; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, and optical waveguides made of glass and crystalline materials; end faces of optical fibers; optical single crystals such as scintillators; solid-state laser single crystals; sapphire substrates for blue laser LEDs; semiconductor single crystals such as SiC, GaP, and GaAs; glass
- the component manufacturing method according to the present embodiment includes a component manufacturing step of obtaining a component using a base (a polished member) polished by the polishing method according to the present embodiment.
- the component according to the present embodiment is a component obtained by the component manufacturing method according to the present embodiment.
- the component according to the present embodiment is not particularly limited, and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip).
- an electronic component is obtained using a base polished by the polishing method according to the present embodiment.
- a semiconductor component e.g., a semiconductor package
- the component manufacturing method according to the present embodiment may include a polishing step of polishing a base by the polishing method according to the present embodiment before the component manufacturing step.
- the component manufacturing method according to the present embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a base (polished member) polished by the polishing method according to the present embodiment.
- the singulation process may be, for example, a process for dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to the present embodiment to obtain chips (e.g., semiconductor chips).
- the electronic component manufacturing method according to the present embodiment may include a process for singulating a base polished by the polishing method according to the present embodiment to obtain electronic components (e.g., semiconductor components).
- the semiconductor component manufacturing method according to the present embodiment may include a process for singulating a base polished by the polishing method according to the present embodiment to obtain semiconductor components (e.g., semiconductor packages).
- the manufacturing method of the component according to this embodiment may include, as one aspect of the component manufacturing process, a connection process for connecting (e.g. electrically connecting) the base (polished member) polished by the polishing method according to this embodiment to another connected body.
- the connected body to be connected to the base polished by the polishing method according to this embodiment is not particularly limited, and may be the base polished by the polishing method according to this embodiment, or may be a connected body different from the base polished by the polishing method according to this embodiment.
- the base and the connected body may be directly connected (connected in a state where the base and the connected body are in contact with each other), or the base and the connected body may be connected via another member (such as a conductive member).
- the connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.
- the connecting step may be a step of connecting the polished surface of the base polished by the polishing method according to the present embodiment to the connected body, or may be a step of connecting the connecting surface of the base polished by the polishing method according to the present embodiment to the connecting surface of the connected body.
- the connecting surface of the base may be the polished surface polished by the polishing method according to the present embodiment.
- the connecting step can obtain a connecting body including the base and the connected body. In the connecting step, if the connecting surface of the base has a metal part, the connected body may be brought into contact with the metal part. In the connecting step, if the connecting surface of the base has a metal part and the connecting surface of the connected body has a metal part, the metal parts may be brought into contact with each other.
- the metal part may contain copper.
- the device according to this embodiment (e.g., an electronic device such as a semiconductor device) comprises a substrate polished by the polishing method according to this embodiment, and at least one component selected from the group consisting of the components according to this embodiment.
- ADP ammonium dihydrogen phosphate
- the above-mentioned cerium oxide mixture which had been delivered after ultrasonic irradiation, was placed in four 500 mL polyethylene containers, each containing 500 g ⁇ 5 g.
- the cerium oxide mixture in each container was centrifuged for two minutes under conditions that resulted in a centrifugal force of 500 G on the periphery. After centrifugation, the supernatant fractions were collected from the containers.
- a slurry was obtained by mixing the supernatant fractions collected from the four containers. The slurry contained approximately 6.0% by mass of cerium oxide particles based on the total mass of the slurry.
- a sample for particle size measurement was obtained by diluting the slurry with pure water so as to obtain a content of abrasive grains with a scattering intensity in a range suitable for measurement.
- the average particle size of the abrasive grains in this sample was measured using a laser diffraction/scattering type particle size distribution measuring device (Microtrac MT3300EXII, manufactured by MicrotracBEL Corp.), and the average particle size of the abrasive grains was found to be 140 nm.
- Each polishing liquid contains 1 part by mass of ammonium polyacrylate or 1 part by mass of ammonium dihydrogen phosphate (ADP) per 100 parts by mass of abrasive grains as a dispersant mixed in the preparation of the above-mentioned slurry.
- ADP ammonium dihydrogen phosphate
- an additive solution was obtained by dissolving each additive in deionized water. Next, equal amounts of the above-mentioned slurry and the additive solution were mixed and stirred for 10 minutes to obtain a concentrated polishing liquid storage liquid containing 5.00 mass% abrasive grains based on the total mass.
- the polishing liquid storage liquid contained 10 times the amount of abrasive grains and additives compared to the final polishing liquid's abrasive grain content of 0.50 mass%, and 2.5 times the amount of abrasive grains and additives compared to the final polishing liquid's abrasive grain content of 2.00 mass%.
- the polishing liquid stock solution was then diluted 10 times with deionized water to obtain the polishing liquids of Examples 1 to 4, 13 to 14, and 21 to 26 and Comparative Examples 1 and 6.
- the polishing liquids of Examples 5 to 12, 15 to 20, and Comparative Examples 2 to 5 were obtained by diluting the polishing liquid stock solution 2.5 times with deionized water.
- the average particle size of the abrasive grains in the polishing liquids of each Example measured in the same manner as the average particle size of the abrasive grains in the slurry described above, was equal to the average particle size of the abrasive grains in the slurry described above.
- ⁇ Zeta potential measurement> An appropriate amount of polishing liquid was put into a Delsa Nano C (trade name) manufactured by Beckman Coulter, Inc., and measurements were performed twice at 25° C. The average value of the displayed zeta potentials was obtained as the zeta potential. In each of the examples and comparative examples, the zeta potential of the abrasive grains was negative as shown in each table.
- a test patterned wafer (model number: Sematech864, manufactured by Advantec Co., Ltd., ⁇ 200 mm) with a silicon oxide film (initial film thickness: 600 nm) having a concave-convex pattern on its surface was prepared as the patterned wafer (PTW).
- the convex portion (line portion) has an initial step height that is 500 nm higher than the concave portion (space portion), and the convex portion is provided with a silicon nitride film (initial film thickness: 140 nm) as a stopper for the silicon oxide film under the assumption that it will be used for evaluation of shallow trench isolation.
- the patterned wafer has multiple 20 mm x 20 mm die units, and each die unit has multiple 4 mm x 4 mm unit areas.
- the pattern wafer has a 4 mm x 4 mm unit area with a parallel line pattern with a pitch of 100 ⁇ m and a Line/Space (L/S) of 10 ⁇ m/90 ⁇ m (protruding part density: 10%) to 90 ⁇ m/10 ⁇ m (protruding part density: 90%) in 10 ⁇ m increments.
- L/S Line/Space
- the above-mentioned evaluation wafer was polished using a polishing device (Applied Materials, product name: Mirra 3400). The above-mentioned evaluation wafer was set on a holder having an adsorption pad for mounting a substrate. A polishing pad made of porous urethane resin (K-groove groove, DuPont (Dow), model number: IC-1010) was attached to a polishing platen having a diameter of 500 mm.
- the holder was placed on the polishing pad with the surface of the evaluation wafer facing down.
- the inner tube pressure, retainer ring pressure, and membrane pressure were set to 14 kPa, 21 kPa, and 14 kPa, respectively.
- the polishing pad attached to the polishing platen was dropped with the above-mentioned polishing liquid (except for Comparative Examples 3 to 5) at a flow rate of 200 mL/min, while rotating the polishing platen and the evaluation wafer at 93 min ⁇ 1 and 87 min ⁇ 1 , respectively, to polish the surface to be polished.
- polishing was performed for 30 seconds.
- the evaluation wafer after polishing was thoroughly washed with pure water using a PVA brush (polyvinyl alcohol brush) and then dried.
- polishing rate ratio (PTW/BKW) of silicon oxide on the convex portion of the patterned wafer to silicon oxide on the blanket wafer was calculated. The results are shown in each table.
- the amount of change in film thickness was measured at a total of 41 measurement points (20 points on either side of the center point), including the center point of the wafer and points spaced 5 mm apart in the diametric direction from the center point (the next measurement point after the measurement point 95 mm from the center was 97 mm from the center).
- the amount of change in film thickness over a 30-second polishing time was measured at these 41 points, and the average value was obtained as the polishing speed of the blanket wafer.
- ILD film 10 ILD film, 20 wiring, 30 silicon oxide film, 40 contact plug, 100, 100a substrate, D step.
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Abstract
Description
[1]砥粒と、添加剤と、水と、を含有し、前記砥粒がセリウム系粒子を含み、前記砥粒のゼータ電位が負であり、前記添加剤が、(A1)下記一般式(1)で表される4-ピロン系化合物を含み、pHが5.0以上である、CMP用研磨液。
[2]前記(A1)成分が、3-ヒドロキシ-2-メチル-4-ピロン、5-ヒドロキシ-2-(ヒドロキシメチル)-4-ピロン、及び、2-エチル-3-ヒドロキシ-4-ピロンからなる群より選ばれる少なくとも一種を含む、[1]に記載のCMP用研磨液。
[3]前記(A1)成分の含有量が0.001~5質量%である、[1]又は[2]に記載のCMP用研磨液。
[4]前記添加剤が、(B)ヒドロキシアルキル基が結合した2以上の窒素原子を有する化合物を更に含む、[1]~[3]のいずれか一つに記載のCMP用研磨液。
[5]前記(B)成分がエチレンジニトリロテトラエタノールを含む、[4]に記載のCMP用研磨液。
[6]pHが8.0以下である、[1]~[5]のいずれか一つに記載のCMP用研磨液。
[7]砥粒と、添加剤と、水と、を含有し、前記砥粒がセリウム系粒子を含み、前記砥粒のゼータ電位が負であり、前記添加剤が、(A2)ピコリン酸化合物を含み、pHが5.0以上である、CMP用研磨液。
[8]前記(A2)成分がピコリン酸を含む、[7]に記載のCMP用研磨液。
[9]前記(A2)成分がヒドロキシピコリン酸を含む、[7]又は[8]に記載のCMP用研磨液。
[10]前記(A2)成分がアミノピコリン酸を含む、[7]~[9]のいずれか一つに記載のCMP用研磨液。
[11]前記(A2)成分の含有量が0.001~5質量%である、[7]~[10]のいずれか一つに記載のCMP用研磨液。
[12]前記添加剤が、(B)ヒドロキシアルキル基が結合した2以上の窒素原子を有する化合物を更に含む、[7]~[11]のいずれか一つに記載のCMP用研磨液。
[13]前記(B)成分がエチレンジニトリロテトラエタノールを含む、[12]に記載のCMP用研磨液。
[14]pHが8.0以下である、[7]~[13]のいずれか一つに記載のCMP用研磨液。
[15][1]~[14]のいずれか一つに記載のCMP用研磨液の構成成分が第1の液と第2の液とに分けて保存され、前記第1の液が、前記砥粒と、水と、を含み、前記第2の液が、前記添加剤の少なくとも一種と、水と、を含む、CMP用研磨液セット。
[16][1]~[14]のいずれか一つに記載のCMP用研磨液を用いて被研磨面を研磨する工程を備える、研磨方法。
[17]前記被研磨面が酸化ケイ素を含む、[16]に記載の研磨方法。
[18][15]に記載のCMP用研磨液セットにおける前記第1の液と前記第2の液とを混合して得られるCMP用研磨液を用いて被研磨面を研磨する工程を備える、研磨方法。
[19]前記被研磨面が酸化ケイ素を含む、[18]に記載の研磨方法。
本実施形態(第1実施形態及び第2実施形態。以下同様)に係るCMP用研磨液は、砥粒と、添加剤と、水と、を含有するCMP用研磨液(以下、場合により、単に「研磨液」という)である。砥粒は、セリウム系粒子(セリウム系化合物を含む粒子)を含み、砥粒のゼータ電位は、負である。第1実施形態に係る研磨液の添加剤は、(A1)下記一般式(1)で表される4-ピロン系化合物((A1)成分)を含む。第2実施形態に係る研磨液の添加剤は、(A2)ピコリン酸化合物((A2)成分)を含む。本実施形態に係る研磨液の添加剤は、(A1)成分及び(A2)成分を含んでよい。本実施形態に係る研磨液のpHは、5.0以上である。
すなわち、負のゼータ電位を有する砥粒を用いて、酸化ケイ素を含む被研磨面を研磨する場合、砥粒と被研磨面との静電的な反発によって酸化ケイ素の高い研磨速度を達成することが難しい場合がある。一方、本実施形態に係る研磨液によれば、セリウム系粒子と共に(A1)成分又は(A2)成分を用いることにより、セリウム系粒子と酸化ケイ素との相互作用が大きくなりやすい(例えば、研磨液中のセリウム系粒子と凸部の酸化ケイ素との化学的な反応(Si-O-Ceの結合に由来する反応)が促進されやすい)こと、酸化ケイ素を含む被研磨面の負電荷の絶対値が減少して砥粒と被研磨面との静電的な反発が抑えられやすいこと等の作用が得られる。そのため、パターンウエハの研磨において、凸部に印加される圧力に応じた研磨速度が得られやすいことから凸部の酸化ケイ素の高い研磨速度を達成できる。
また、セリウム系粒子と共に(A1)成分又は(A2)成分を用いる場合においてpHが低いと、優れた砥粒の分散安定性を達成できない場合がある。一方、本実施形態に係る研磨液によれば、pHが5.0以上であることにより、砥粒と被研磨面との静電的な反発が過剰に強まらない範囲で砥粒のゼータ電位が負に維持されやすく、砥粒同士の静電的な反発が好適に維持されやすいことから、優れた砥粒の分散安定性を達成できる。
本実施形態に係る研磨液の一態様によれば、凹凸パターンを有さないブランケットウエハにおける酸化ケイ素に対して、凹凸パターンを有するパターンウエハの凸部における酸化ケイ素の高い研磨速度比を達成可能であり、例えば、凹凸パターンを有さないブランケットウエハにおける酸化ケイ素に対して、パターンウエハのLine/Space(L/S)=20μm/80μmの領域における凸部の酸化ケイ素の高い研磨速度比を達成できる。本実施形態に係る研磨液の一態様によれば、後述の実施例に記載の評価方法において、ブランケットウエハにおける酸化ケイ素に対する、パターンウエハのL/S=20μm/80μmの領域における凸部の酸化ケイ素の研磨速度比として、例えば0.70以上(好ましくは、0.90以上、1.00以上、1.50以上、2.00以上等)を得ることができる。凹凸パターンを有さないブランケットウエハにおける酸化ケイ素に対して、凹凸パターンを有するパターンウエハの凸部における酸化ケイ素の高い研磨速度比を得ることにより、凸部を選択的に研磨可能な特性として高い平坦性を実現することができる。
本実施形態に係る研磨液において砥粒は、セリウム系粒子(セリウム系化合物を含む粒子)を含む。セリウム系粒子を砥粒として用いることにより、被研磨面に生じる研磨傷を低減しつつパターンウエハの凸部における酸化ケイ素の高い研磨速度を得やすい。
[(A1)成分:4-ピロン系化合物]
第1実施形態に係る研磨液の添加剤は、(A1)成分として、一般式(1)で表される4-ピロン系化合物(以下、場合により、単に「4-ピロン系化合物」という)を含む。4-ピロン系化合物を用いることで、研磨液と酸化ケイ素との相互作用が大きくなることにより研磨速度が高くなりやすいと推測される。
第2実施形態に係る研磨液の添加剤は、(A2)成分として、ピコリン酸化合物を含む。(A2)成分を用いることで、研磨液と酸化ケイ素との相互作用が大きくなることにより研磨速度が高くなりやすいと推測される。
本実施形態に係る研磨液の添加剤は、(B)成分として、ヒドロキシアルキル基が結合した2以上の窒素原子を有する化合物(窒素含有ヒドロキシアルキル化合物;但し、(A1)成分に該当する化合物を除く)を含んでよい。(B)成分を用いることにより、研磨液と凹凸パターンにおける凸部の酸化ケイ素との相互作用を大きくすることにより凸部の酸化ケイ素の高い研磨速度を得やすいと共に、ストッパ材料として使用可能な窒化ケイ素の研磨速度を抑制しやすい。(B)成分では、窒素原子にヒドロキシアルキル基が直接結合しており、窒素原子に直接結合したアルキル基にヒドロキシ基が直接結合している。(B)成分は、窒素原子に結合したヒドロキシアルキル基として、ヒドロキシ基以外の置換基を有しないアルキル基を用いることができる。
本実施形態に係る研磨液の添加剤は、所望とする特性に合わせて他の成分(上述の各成分に該当しない成分)を更に含んでよい。このような成分としては、非イオン性ポリマ;カチオン性化合物;後述するpH調整剤;エタノール、アセトン等の極性溶媒;環状モノカルボン酸などが挙げられる。
水は、特に制限されるものではないが、脱イオン水、イオン交換水及び超純水からなる群より選ばれる少なくとも一種を含んでよい。
本実施形態に係る研磨液のpHは、優れた砥粒の分散安定性を達成する観点から、5.0以上である。アニオン系分散剤を用いて砥粒のゼータ電位が負に調整されている場合においてpHが5.0以上であると、アニオン系分散剤が充分に解離して砥粒のゼータ電位が負に維持されやすい。pHは、優れた砥粒の分散安定性を達成しやすい観点、パターンウエハの凸部における酸化ケイ素の高い研磨速度が得られやすい観点、ブランケットウエハにおける酸化ケイ素の高速研磨を達成しやすい観点、及び、窒化ケイ素の研磨速度を抑制しやすい観点から、下記の範囲であってよい。pHは、12.0以下、11.0以下、10.5以下、10.5未満、10.0以下、10.0未満、9.5以下、9.0以下、9.0未満、8.8以下、8.5以下、8.2以下、8.0以下、8.0未満、7.8以下、7.5以下、7.2以下、7.0以下、7.0未満、6.8以下、6.7以下、6.5以下、6.2以下、6.0以下、6.0未満、5.7以下、5.5以下、又は、5.4以下であってよい。pHは、5.0超、5.2以上、5.4以上、5.5以上、5.5超、5.7以上、6.0以上、6.0超、6.2以上、6.5以上、6.7以上、6.8以上、7.0以上、7.0超、7.2以上、7.5以上、7.8以上、8.0以上、8.0超、又は、8.2以上であってよい。これらの観点から、pHは、5.0~12.0、5.0~9.0、5.0~7.5、6.0~12.0、6.0~9.0、6.0~7.5、6.5~12.0、6.5~9.0、又は、6.5~7.5であってよい。pHは、実施例に記載の方法により測定できる。
本実施形態に係る研磨液は、(a)通常タイプ、(b)濃縮タイプ及び(c)複数液タイプ(例えば2液タイプ。CMP用研磨液セット)に分類でき、タイプによってそれぞれ調製法及び使用法が相違する。(a)通常タイプは、研磨時に希釈等の前処理をせずにそのまま使用できる研磨液である。(b)濃縮タイプは、保管又は輸送の利便性を考慮し、(a)通常タイプと比較して含有成分を濃縮した研磨液である。(c)複数液タイプは、保管時又は輸送時には、含有成分を複数の液に分けた状態(例えば、一定の成分を含む第1の液と、他の成分を含む第2の液とに分けた状態)としておき、使用に際してこれらの液を混合して使用する研磨液である。
本実施形態に係る研磨方法は、本実施形態に係る研磨液を用いて被研磨面を研磨する研磨工程を備える。研磨工程で用いられる研磨液は、上述の研磨液セットにおける第1の液と第2の液とを混合して得られる研磨液であってもよい。すなわち、本実施形態に係る研磨方法は、上述の研磨液セットにおける第1の液と第2の液とを混合して得られる研磨液を用いて被研磨面を研磨する研磨工程を備えてよい。
本実施形態に係る部品の製造方法は、本実施形態に係る研磨方法により研磨された基体(被研磨部材)を用いて部品を得る部品作製工程を備える。本実施形態に係る部品は、本実施形態に係る部品の製造方法により得られる部品である。本実施形態に係る部品は、特に限定されないが、電子部品(例えば、半導体パッケージ等の半導体部品)であってよく、ウエハ(例えば半導体ウエハ)であってよく、チップ(例えば半導体チップ)であってよい。本実施形態に係る部品の製造方法の一態様として、本実施形態に係る電子部品の製造方法では、本実施形態に係る研磨方法により研磨された基体を用いて電子部品を得る。本実施形態に係る部品の製造方法の一態様として、本実施形態に係る半導体部品の製造方法では、本実施形態に係る研磨方法により研磨された基体を用いて半導体部品(例えば半導体パッケージ)を得る。本実施形態に係る部品の製造方法は、部品作製工程の前に、本実施形態に係る研磨方法により基体を研磨する研磨工程を備えてよい。
炭酸セリウム水和物40kgをアルミナ製容器10個に分けて入れ、それぞれ830℃で2時間、空気中で焼成して黄白色の粉末を計20kg得た。この粉末についてX線回折法で相同定を行い、当該粉末が多結晶体の酸化セリウムを含むことを確認した。焼成によって得られた粉末の粒径をSEMで観察したところ、20~100μmの範囲であった。次いで、ジェットミルを用いて酸化セリウム粉末20kgの乾式粉砕を行うことにより酸化セリウム粉末を得た。粉砕後の酸化セリウム粉末の比表面積は9.4m2/gであった。比表面積の測定はBET法によって実施した。
上記で得られた酸化セリウム粉末15.0kg及び脱イオン水84.85kgを容器内に入れて混合した。次に、分散剤として、0.375kgのポリアクリル酸アンモニウムの水溶液(濃度40質量%、分子量:約10000)又は0.15kgのリン酸二水素アンモニウム(ADP)を添加した後、10分間撹拌することにより酸化セリウム混合液を得た。この酸化セリウム混合液を別の容器に30分かけて送液した。その間、送液する配管内で、酸化セリウム混合液に対して超音波周波数400kHzにて超音波照射を行った。
上述のスラリ、各添加剤及び脱イオン水を下記の手順で混合することにより、下記各表の組成(残部:脱イオン水)を有する研磨液を得た(但し、比較例1、2及び6において、上述のスラリの調製時に混合した分散剤以外の添加剤は不使用)。表中、「THEED」は2,2’,2’’,2’’’-エチレンジニトリロテトラエタノールを意味する。各研磨液は、上述のスラリの調製時に混合した分散剤として、砥粒100質量部に対して1質量部のポリアクリル酸アンモニウム又は1質量部のリン酸二水素アンモニウム(ADP)を含有している。
ベックマン・コールター株式会社製の商品名「DelsaNano C」内に適量の研磨液を投入し、25℃において測定を2回行った。表示されたゼータ電位の平均値をゼータ電位として得た。実施例及び比較例のそれぞれにおいて、各表に示すように砥粒のゼータ電位は負であった。
下記の条件で研磨液のpHを測定した。結果を各表に示す。
測定温度:25℃
測定装置:株式会社堀場製作所の商品名:Model(D-71)
測定方法:フタル酸塩pH標準液(pH:4.01)と、中性リン酸塩pH標準液(pH:6.86)と、ホウ酸塩pH標準液(pH:9.18)とをpH標準液として用いてpHメーターを3点校正した後、pHメーターの電極を研磨液に入れて、2min以上経過して安定した後のpHを前記測定装置により測定した。
調製直後の上述の研磨液を1週間(168時間)静置し、上述のスラリにおける砥粒の平均粒径と同様の方法により、調製直後から3時間経過時及び1週間経過時の砥粒の平均粒径を測定した。3時間又は1週間経過時の砥粒の平均粒径の変化率として、「[(研磨液における3時間又は1週間経過時の平均粒径-上述のスラリにおける砥粒の平均粒径)/上述のスラリにおける砥粒の平均粒径]×100」を算出した。1週間経過時の砥粒の平均粒径の変化率(及び、3時間経過時の砥粒の平均粒径の変化率)が4%以下である場合を「A」と判定し、1週間経過時の砥粒の平均粒径の変化率が4%を超えるものの3時間経過時の砥粒の平均粒径の変化率が4%以下である場合を「B」と判定し、3時間経過時の砥粒の平均粒径の変化率が4%を超える場合を「C」と判定した。結果を各表に示す。
(評価用ウエハの準備)
ブランケットウエハ(BKW)として、表面に酸化ケイ素膜(SiO2、初期膜厚:1000nm)を有するφ200mmのパターン無しのウエハと、表面に窒化ケイ素膜(SiN、初期膜厚:200nm)を有するφ200mmのパターン無しのウエハと、を準備した。
研磨装置(アプライドマテリアル製、商品名:Mirra3400)を用いて上述の評価用ウエハを研磨した。基体取り付け用の吸着パッドを有するホルダーに上述の評価用ウエハをセットした。直径500mmの研磨定盤に多孔質ウレタン樹脂製の研磨パッド(K-groove溝、DuPont(Dow)社製、型番:IC-1010)を貼り付けた。
光干渉式膜厚測定装置(ナノメトリクス・ジャパン株式会社製、商品名:AFT-5100)を用いて下記のとおり研磨前後の被研磨膜の膜厚変化量を測定し、研磨速度を得た。また、ブランケットウエハにおける酸化ケイ素に対するパターンウエハの凸部における酸化ケイ素の研磨速度比(PTW/BKW)を算出した。結果を各表に示す。
Claims (19)
- 前記(A1)成分が、3-ヒドロキシ-2-メチル-4-ピロン、5-ヒドロキシ-2-(ヒドロキシメチル)-4-ピロン、及び、2-エチル-3-ヒドロキシ-4-ピロンからなる群より選ばれる少なくとも一種を含む、請求項1に記載のCMP用研磨液。
- 前記(A1)成分の含有量が0.001~5質量%である、請求項1に記載のCMP用研磨液。
- 前記添加剤が、(B)ヒドロキシアルキル基が結合した2以上の窒素原子を有する化合物を更に含む、請求項1に記載のCMP用研磨液。
- 前記(B)成分がエチレンジニトリロテトラエタノールを含む、請求項4に記載のCMP用研磨液。
- pHが8.0以下である、請求項1に記載のCMP用研磨液。
- 砥粒と、添加剤と、水と、を含有し、
前記砥粒がセリウム系粒子を含み、
前記砥粒のゼータ電位が負であり、
前記添加剤が、(A2)ピコリン酸化合物を含み、
pHが5.0以上である、CMP用研磨液。 - 前記(A2)成分がピコリン酸を含む、請求項7に記載のCMP用研磨液。
- 前記(A2)成分がヒドロキシピコリン酸を含む、請求項7に記載のCMP用研磨液。
- 前記(A2)成分がアミノピコリン酸を含む、請求項7に記載のCMP用研磨液。
- 前記(A2)成分の含有量が0.001~5質量%である、請求項7に記載のCMP用研磨液。
- 前記添加剤が、(B)ヒドロキシアルキル基が結合した2以上の窒素原子を有する化合物を更に含む、請求項7に記載のCMP用研磨液。
- 前記(B)成分がエチレンジニトリロテトラエタノールを含む、請求項12に記載のCMP用研磨液。
- pHが8.0以下である、請求項7に記載のCMP用研磨液。
- 請求項1~14のいずれか一項に記載のCMP用研磨液の構成成分が第1の液と第2の液とに分けて保存され、前記第1の液が、前記砥粒と、水と、を含み、前記第2の液が、前記添加剤の少なくとも一種と、水と、を含む、CMP用研磨液セット。
- 請求項1~14のいずれか一項に記載のCMP用研磨液を用いて被研磨面を研磨する工程を備える、研磨方法。
- 前記被研磨面が酸化ケイ素を含む、請求項16に記載の研磨方法。
- 請求項15に記載のCMP用研磨液セットにおける前記第1の液と前記第2の液とを混合して得られるCMP用研磨液を用いて被研磨面を研磨する工程を備える、研磨方法。
- 前記被研磨面が酸化ケイ素を含む、請求項18に記載の研磨方法。
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