Polishing liquid, polishing method and production method of semiconductor device

Abstract

To provide a polishing liquid capable of polishing a silicon-based material (provided that silicon nitride is excluded) at a high polishing speed.SOLUTION: A polishing liquid for polishing a member to be polished containing a silicon-based material (provided that silicon nitride is excluded) contains an abrasive grain and a nitrogen-containing heterocyclic compound, where the abrasive grain includes a cerium-based compound, the nitrogen-containing heterocyclic compound includes an oxygen atom, and the oxygen atom bonds to a nitrogen atom constituting a hetero ring. A polishing liquid for polishing a member to be polished containing a silicon-based material (provided that silicon nitride is excluded) contains an abrasive grain and a nitrogen-containing heterocyclic compound, where the abrasive grain includes a cerium-based compound, and the nitrogen-containing heterocyclic compound has a hydroxyl group.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a polishing liquid, a polishing method, a method for manufacturing a semiconductor device, and the like. [Background technology]

[0002] In recent years, the importance of processing technologies for higher density and finer patterning has been increasing in the manufacturing process of electronic devices. One of the processing technologies, chemical mechanical polishing (CMP), is essential for forming shallow trench isolation (STI), planarizing premetal insulating materials or interlayer insulating materials, forming plugs or buried metal wiring, etc. in the manufacturing process of electronic devices. Materials to be polished by the CMP method include amorphous silicon, polysilicon, single crystal silicon, silicon oxide, silicon nitride, tungsten, copper, etc., and Patent Document 1 describes polishing silicon oxide using abrasive grains containing cerium oxide. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-106994 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there is a demand for polishing silicon-based materials such as amorphous silicon at a high polishing rate, but it is difficult to polish silicon-based materials at a high polishing rate.

[0005] An object of one aspect of the present disclosure is to provide a polishing liquid capable of polishing silicon-based materials (excluding silicon nitride) at a high polishing rate.Another object of the present disclosure is to provide a polishing method using the polishing liquid.Another object of the present disclosure is to provide a method for manufacturing a semiconductor device using a polished member polished by the polishing method. [Means for solving the problem]

[0006] The present disclosure relates in some aspects to the following items [1] to

[15] , etc. [1] A polishing liquid for polishing a workpiece containing a silicon-based material (excluding silicon nitride), comprising: The abrasive grains and a nitrogen-containing heterocyclic compound are contained, The abrasive grains contain a cerium-based compound, the nitrogen-containing heterocyclic compound contains an oxygen atom, the oxygen atom is bonded to a nitrogen atom constituting a heterocycle. [2] The polishing liquid according to [1], wherein the nitrogen-containing heterocyclic compound has a hydroxy group. [3] A polishing liquid for polishing a workpiece containing a silicon-based material (excluding silicon nitride), comprising: The abrasive grains and a nitrogen-containing heterocyclic compound are contained, The abrasive grains contain a cerium-based compound, The polishing liquid, wherein the nitrogen-containing heterocyclic compound has a hydroxy group. [4] The polishing liquid according to any one of [1] to [3], wherein the abrasive grains contain cerium oxide. [5] The polishing liquid according to any one of [1] to [4], wherein the nitrogen-containing heterocyclic compound contains one nitrogen atom as a heteroatom. [6] The polishing liquid according to any one of [1] to [5], wherein the number of members of the heterocycle of the nitrogen-containing heterocyclic compound is 6. [7] The polishing liquid according to [2] or [3], wherein the hydroxy group is bonded to a carbon atom constituting a heterocycle. [8] The polishing liquid according to [7], wherein the carbon atom is bonded to a nitrogen atom constituting the heterocycle. [9] The polishing liquid according to any one of [1] to [8], wherein the content of the nitrogen-containing heterocyclic compound is more than 0.015 mass % based on the total mass of the polishing liquid.

[10] The polishing liquid according to any one of [1] to [9], wherein the content of the nitrogen-containing heterocyclic compound is more than 0.035 mass % based on the total mass of the polishing liquid.

[11] The polishing liquid according to any one of [1] to

[10] , wherein the silicon-based material contains at least one selected from the group consisting of amorphous silicon, polysilicon, and single crystal silicon.

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

[11] , wherein the polished member further contains silicon nitride.

[13] A polishing method comprising a step of polishing a workpiece containing a silicon-based material with the polishing liquid according to any one of [1] to

[12] .

[14] A method for producing a semiconductor device, comprising obtaining a semiconductor device using a polished member polished by the polishing method according to

[13] . Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide a polishing liquid capable of polishing silicon-based materials (excluding silicon nitride) at a high polishing rate. According to another aspect of the present disclosure, it is possible to provide a polishing method using the polishing liquid. According to another aspect of the present disclosure, it is possible to provide a method for manufacturing a semiconductor device using a member to be polished by the polishing method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present disclosure will be described in detail.

[0009] In this specification, the numerical range indicated by "~" 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. In the numerical ranges described in stages in this specification, 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. In the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. Unless otherwise specified, 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 multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. The term "layer" or "film" includes a structure having a shape formed over the entire surface as well as a structure having a shape formed on a part of the surface when observed in a plan view. The term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. In this specification, the phrase "the present embodiment" includes the first embodiment and the second embodiment.

[0010] <Polishing liquid> The polishing liquid according to this embodiment is a polishing liquid for polishing a member to be polished that contains a silicon-based material (excluding silicon nitride), and contains at least abrasive grains and a nitrogen-containing heterocyclic compound. The abrasive grains include a cerium-based compound. In a first embodiment, the nitrogen-containing heterocyclic compound contains an oxygen atom, and the oxygen atom is bonded to a nitrogen atom constituting the heterocycle. In a second embodiment, the nitrogen-containing heterocyclic compound has a hydroxy group.

[0011] The polishing liquid according to this embodiment can polish silicon-based materials (excluding silicon nitride) at a high polishing rate.

[0012] Examples of silicon-based materials include amorphous silicon, polysilicon, single crystal silicon, and silicon oxide. In this specification, silicon nitride is not treated as a silicon-based material. The silicon-based material may be at least one selected from the group consisting of amorphous silicon, polysilicon, single crystal silicon, and silicon oxide, or may be at least one selected from the group consisting of amorphous silicon, polysilicon, and single crystal silicon. The silicon-based material may not include polysilicon, may not include single crystal silicon, and may not include silicon oxide.

[0013] The polishing liquid according to this embodiment can polish amorphous silicon at a high polishing rate; for example, in the evaluation method described in the Examples below, the polishing rate for amorphous silicon can be more than 1700 Å / min, 1720 Å / min or more, 1800 Å / min or more, 1900 Å / min or more, 2000 Å / min or more, 2100 Å / min or more, 2200 Å / min or more, 2300 Å / min or more, or 2400 Å / min or more.

[0014] The polishing liquid according to this embodiment can polish silicon oxide at a high polishing rate; for example, in the evaluation method described in the Examples below, the polishing rate for silicon oxide can be 20,400 Å / min or more, 20,500 Å / min or more, 20,600 Å / min or more, 20,700 Å / min or more, 20,800 Å / min or more, 20,900 Å / min or more, 21,000 Å / min or more, 21,100 Å / min or more, 21,200 Å / min or more, or 21,300 Å / min or more.

[0015] The polishing liquid according to this embodiment can suppress the polishing rate of silicon nitride, and for example, in the evaluation method described in the Examples below, the polishing rate of silicon nitride can be 3400 Å / min or less, 3300 Å / min or less, 3200 Å / min or less, 3100 Å / min or less, 3000 Å / min or less, 2900 Å / min or less, 2800 Å / min or less, 2700 Å / min or less, or 2600 Å / min or less.

[0016] The polishing liquid according to this embodiment can improve the polishing rate ratio of amorphous silicon to silicon oxide (amorphous silicon / silicon oxide). For example, in the evaluation method described in the examples below, the polishing rate ratio of amorphous silicon to silicon oxide can be 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, or 0.12 or more.

[0017] The polishing liquid according to this embodiment can improve the polishing rate ratio of amorphous silicon to silicon nitride (amorphous silicon / silicon nitride). For example, in the evaluation method described in the examples below, the polishing rate ratio of amorphous silicon to silicon nitride can be 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more.

[0018] The factors that produce these effects are not necessarily clear, but are presumed to be as follows, although the factors are not limited to the following. First, in the first embodiment, the nitrogen-containing heterocyclic compound contains an oxygen atom, and the oxygen atom is bonded to a nitrogen atom constituting the heterocycle, so that the nitrogen-containing heterocyclic compound is selectively adsorbed to the silicon-based material, which promotes polishing of the silicon-based material by the abrasive grains containing the cerium compound, thereby achieving a high polishing rate of the silicon-based material. In the second embodiment, the nitrogen-containing heterocyclic compound has a hydroxyl group, and thus the nitrogen-containing heterocyclic compound is selectively adsorbed to the silicon-based material, which promotes polishing of the silicon-based material with the abrasive grains containing the cerium compound, thereby achieving a high polishing rate of the silicon-based material.

[0019] (Abrasive grain) The polishing liquid according to the present embodiment contains abrasive grains. The abrasive grains contain a cerium-based compound from the viewpoint of polishing silicon-based materials at a high polishing rate. Examples of the cerium-based compound 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 abrasive grains may contain cerium oxide from the viewpoint of polishing silicon-based materials at a high polishing rate.

[0020] When the abrasive grains contain cerium oxide, the abrasive grains may be cerium oxide particles. As the cerium oxide particles, colloidal ceria, amorphous ceria, ceria-coated silica, etc. may be used. The cerium oxide particles may be cerium oxide particles whose surfaces are modified with an alkyl group, composite particles in which other particles are attached to the surfaces of cerium oxide particles, composite particles in which cerium oxide particles are attached to the surfaces of other particles, etc.

[0021] Cerium oxide particles can be obtained by oxidizing a cerium salt such as carbonate, nitrate, sulfate, or oxalate. Examples of the oxidation method include a calcination method in which a cerium salt is calcined at about 600 to 900° C., and a chemical oxidation method in which a cerium salt is oxidized using an oxidizing agent such as hydrogen peroxide. The method for producing cerium oxide particles may be a calcination method from the viewpoint of polishing silicon-based materials at a higher polishing rate, or a chemical oxidation method from the viewpoint of preventing polishing scratches from occurring on the polished surface after polishing.

[0022] Colloidal ceria can be obtained by a build-up process, for example, by the method described in Examples 1 to 4 of JP-A-2010-505735.

[0023] Examples of the amorphous ceria include pulverized ceria. Examples of the pulverized ceria include sintered pulverized ceria obtained by sintering and pulverizing a cerium compound such as cerium carbonate or cerium nitrate, and single crystal pulverized ceria obtained by wet-pulverizing ceria particles in the presence of an inorganic acid or an organic acid. Examples of the inorganic acid used in the wet-pulverization include nitric acid, and examples of the organic acid include organic acids having a carboxyl group, specifically at least one selected from acetic acid, propionic acid, picolinic acid, glutamic acid, aspartic acid, aminobenzoic acid, and p-hydroxybenzoic acid. Examples of the wet-pulverization method include wet-pulverization using a planetary bead mill or the like.

[0024] Examples of ceria-coated silica include composite particles having a structure in which at least a part of the surface of silica particles is coated with granular ceria, as described in Examples 1 to 14 of JP-A No. 2015-63451 and Examples 1 to 4 of JP-A No. 2013-119131. The composite particles can be obtained, for example, by depositing ceria on silica particles.

[0025] When the abrasive grains contain cerium oxide, the lower limit of the cerium oxide content may be 50 mass% or more, more than 50 mass%, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, or 100 mass% (an embodiment essentially consisting of cerium oxide) based on the entire abrasive grains (all abrasive grains contained in the polishing liquid; the same applies below), from the viewpoint of polishing silicon-based materials at a higher polishing rate.

[0026] From the viewpoint of polishing silicon-based materials at a higher polishing rate, the lower limit of the average particle size of the abrasive grains in the polishing liquid may be 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, more than 0.1 μm, 0.12 μm or more, 0.14 μm or more, 0.16 μm or more, 0.18 μm or more, 0.2 μm or more, more than 0.2 μm, 0.21 μm or more, 0.22 μm or more, or 0.23 μm or more. From the viewpoint of easily suppressing scratches on the polished surface, the upper limit of the average particle size of the abrasive grains may be 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, less than 1 μm, 0.8 μm or less, 0.6 μm or less, 0.5 μm or less, less than 0.5 μm, 0.4 μm or less, 0.35 μm or less, 0.3 μm or less, less than 0.3 μm, 0.29 μm or less, 0.28 μm or less, 0.27 μm or less, 0.26 μm or less, 0.25 μm or less, or 0.24 μm or less. From these viewpoints, the average particle size of the abrasive grains may be 0.01 to 5 μm, 0.1 to 1 μm, or 0.2 to 0.5 μm.

[0027] The "average particle size" of the abrasive grains refers to the average secondary particle size of the abrasive grains. For example, the average particle size of the abrasive grains refers to D50 measured for the polishing liquid using a laser diffraction / scattering type particle size distribution measuring device Microtrac MT3300EX II (manufactured by Microtrac Bell Co., Ltd.).

[0028] From the viewpoint of polishing silicon-based materials at a higher polishing rate, the lower limit of the volume mean diameter (MV) of the abrasive grains in the polishing liquid may be 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, more than 0.1 μm, 0.12 μm or more, 0.15 μm or more, 0.2 μm or more, more than 0.2 μm, 0.22 μm or more, 0.24 μm or more, 0.25 μm or more, 0.26 μm or more, 0.27 μm or more, or 0.28 μm or more. From the viewpoint of easily suppressing scratches on the polished surface, the upper limit of the volume mean diameter (MV) of the abrasive grains may be 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, 0.6 μm or less, 0.5 μm or less, 0.45 μm or less, 0.4 μm or less, less than 0.4 μm, 0.38 μm or less, 0.36 μm, 0.35 μm or less, 0.34 μm or less, 0.33 μm or less, 0.32 μm or less, 0.31 μm or less, 0.3 μm or less, less than 0.3 μm, or 0.29 μm or less. From these viewpoints, the volume mean diameter (MV) of the abrasive grains may be 0.01 to 5 μm, 0.1 to 1 μm, or 0.2 to 0.5 μm.

[0029] The content of the abrasive grains may be in the following range based on the total mass of the polishing liquid. The lower limit of the content of the abrasive grains may be 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.5 mass% or more, 0.8 mass% or more, 1 mass% or more, 1.2 mass% or more, 1.4 mass% or more, 1.6 mass% or more, 1.8 mass% or more, or 2 mass% or more, from the viewpoint of polishing silicon-based materials at a higher polishing rate. The upper limit of the content of the abrasive grains may be 20 mass% or less, 18 mass% or less, 16 mass% or less, 14 mass% or less, 12 mass% or less, 10 mass% or less, 8 mass% or less, 6 mass% or less, 5 mass% or less, 4 mass% or less, 3 mass% or less, or 2 mass% or less, from the viewpoint of easily obtaining excellent dispersion stability of the abrasive grains. From these viewpoints, the content of the abrasive grains may be 0.01 to 20 mass%, or 0.1 to 10 mass%.

[0030] (Additives) [Nitrogen-containing heterocyclic compound] The polishing liquid according to this embodiment contains a nitrogen-containing heterocyclic compound. In a first embodiment, the nitrogen-containing heterocyclic compound contains an oxygen atom, and the oxygen atom is bonded to a nitrogen atom constituting a heterocycle. In a second embodiment, the nitrogen-containing heterocyclic compound has a hydroxy group.

[0031] The heterocycle of the nitrogen-containing heterocyclic compound according to the present embodiment contains a nitrogen atom as a heteroatom. From the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials, the nitrogen-containing heterocyclic compound may contain three or less nitrogen atoms as a heteroatom, may contain two or less nitrogen atoms, or may contain one nitrogen atom.

[0032] The number of heterocycles in the nitrogen-containing heterocyclic compound according to this embodiment may be 1 to 3, 1 to 2, or 1, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials.

[0033] The number of ring members of the heterocycle of the nitrogen-containing heterocyclic compound according to this embodiment may be 4 or more, 5 or more, or 6 or more, and may be 8 or less, 7 or less, or 6 or less, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials. The number of ring members of the heterocycle of the nitrogen-containing heterocyclic compound may be 6, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials. The nitrogen-containing heterocyclic compound may have a pyridine ring as the heterocycle.

[0034] In the first embodiment, the nitrogen-containing heterocyclic compound contains an oxygen atom, and the oxygen atom is bonded to a nitrogen atom constituting a heterocycle. The oxygen atom may not be a part of a heterocycle, and may be bonded only to a nitrogen atom. In the first embodiment, the nitrogen-containing heterocyclic compound may contain, for example, a compound represented by the following general formula (1) or a salt thereof. [ka] [In the formula, R11 , R 12 , R 13 , R 14 , and R 15 each independently represents a hydrogen atom, a halogen atom, an alkyl group, or a hydroxyl group.

[0035] In the general formula (1), the alkali group may be a substituted or unsubstituted alkyl group. Examples of the substituent of the alkyl group include a carboxy group, a hydroxy group, an amino group, a sulfo group, and a nitro group. The number of carbon atoms in the alkyl group may be 10 or less, 8 or less, 6 or less, 4 or less, 3 or less, 2 or less, or 1, or may be 1 or more, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials.

[0036] In the general formula (1), from the viewpoint of polishing the silicon-based material at a higher polishing rate and from the viewpoint of suppressing the polishing rate of the insulating material, R 11 , R 12 , R 13 , R 14 , and R 15 At least one of R may be a hydroxy group; 11 , and R 15 In other words, when the nitrogen-containing heterocyclic compound contains an oxygen atom, the oxygen atom is bonded to a nitrogen atom constituting the heterocycle, and also has a hydroxyl group, the hydroxyl group may be bonded to a carbon atom constituting the heterocycle, and the carbon atom may be bonded to a nitrogen atom constituting the heterocycle, from the viewpoint of polishing the silicon-based material at a higher polishing rate and from the viewpoint of suppressing the polishing rate of the insulating material.

[0037] Examples of the salt of the compound represented by the general formula (1) include alkali metal salts, alkaline earth metal salts, organic amine salts such as ethanolamine salts, and ammonium salts.

[0038] In the first embodiment, the nitrogen-containing heterocyclic compound may be, for example, pyridine-N-oxide, 2-hydroxypyridine-N-oxide, 3-hydroxypyridine-N-oxide, 4-hydroxypyridine-N-oxide, 2-methylpyridine-N-oxide, 2-chloropyridine-N-oxide, 2-methyl-4-nitropyridine-N-oxide, 3-methyl-4-nitropyridine-N-oxide, 2,6-dimethylpyridine-N-oxide, picolinic acid-N-oxide, nicotinic acid-N-oxide, and salts thereof.

[0039] In the second embodiment, the nitrogen-containing heterocyclic compound has a hydroxy group. In the second embodiment, from the viewpoint of polishing a silicon-based material at a higher polishing rate and from the viewpoint of suppressing the polishing rate of an insulating material, the hydroxy group of the nitrogen-containing heterocyclic compound may be bonded to a carbon atom constituting the heterocycle, or may be bonded to a carbon atom constituting the heterocycle and the carbon atom may be bonded to a nitrogen atom constituting the heterocycle.

[0040] In the second embodiment, the number of hydroxy groups in the nitrogen-containing heterocyclic compound may be equal to or greater than 1. From the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials, the number of hydroxy groups in the nitrogen-containing heterocyclic compound may be 10 or less, 8 or less, 6 or less, 4 or less, 3 or less, or 2 or less.

[0041] In the second embodiment, the nitrogen-containing heterocyclic compound may contain an oxygen atom, and the oxygen atom may be bonded to a nitrogen atom constituting a heterocycle. In this case, the nitrogen-containing heterocyclic compound may contain, for example, a compound represented by the following general formula (2) or a salt thereof. [ka] [In the formula, R 21 , R 22 , R 23 , R 24 , and R 25 each independently represents a hydrogen atom, a halogen atom, an alkyl group, or a hydroxyl group; R21 , R 22 , R 23 , R 24 , and R 25 At least one of the groups represents a hydroxy group or an alkyl group having a hydroxy group.

[0042] In the general formula (2), the alkali group may be a substituted or unsubstituted alkyl group. Examples of the substituent of the alkyl group include a carboxy group, a hydroxy group, an amino group, a sulfo group, and a nitro group. The number of carbon atoms in the alkyl group may be 10 or less, 8 or less, 6 or less, 4 or less, 3 or less, 2 or less, or 1, or may be 1 or more, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials.

[0043] Examples of the salt of the compound represented by the general formula (2) include alkali metal salts, alkaline earth metal salts, organic amine salts such as ethanolamine salts, and ammonium salts.

[0044] In the second embodiment, the nitrogen-containing heterocyclic compound may be, for example, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-pyridinemethanol, 3-pyridinemethanol, 4-pyridinemethanol, 2-hydroxypyridine-N-oxide, 3-hydroxypyridine-N-oxide, or 4-hydroxypyridine-N-oxide.

[0045] The nitrogen-containing heterocyclic compound according to the present embodiment may contain an oxygen atom, the oxygen atom being bonded to a nitrogen atom constituting a heterocycle, and may have a hydroxyl group, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials. Examples of such compounds include 2-hydroxypyridine-N-oxide, 3-hydroxypyridine-N-oxide, and 4-hydroxypyridine-N-oxide. The nitrogen-containing heterocyclic compound may contain 2-hydroxypyridine-N-oxide, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials.

[0046] The molecular weight of the nitrogen-containing heterocyclic compound according to this embodiment may be in the following ranges from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials. The molecular weight of the nitrogen-containing heterocyclic compound may be 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, more than 100, or 110 or more. The molecular weight of the nitrogen-containing heterocyclic compound may be 1000 or less, less than 1000, 800 or less, 600 or less, 500 or less, less than 500, 400 or less, 300 or less, 200 or less, 150 or less, 140 or less, 130 or less, 120 or less, or less than 120. From these viewpoints, the molecular weight of the nitrogen-containing heterocyclic compound may be 60 to 1000, 80 to 500, or 100 to 200.

[0047] From the viewpoint of polishing silicon-based materials at a higher polishing rate and from the viewpoint of suppressing the polishing rate of insulating materials, the content of the nitrogen-containing heterocyclic compound according to this embodiment may be 0.0001% by mass or more, 0.0003% by mass or more, 0.0005% by mass or more, 0.001% by mass or more, more than 0.001% by mass, 0.003% by mass or more, 0.004% by mass or more, 0.005% by mass or more, 0.008% by mass or more, 0.01% by mass or more, more than 0.01% by mass, 0.015% by mass or more, more than 0.015% by mass, 0.02% by mass or more, 0.03% by mass or more, 0.035% by mass or more, more than 0.035% by mass, 0.04% by mass or more, 0.045% by mass or more, or 0.05% by mass or more based on the total mass of the polishing liquid. From the viewpoint of improving uniformity within the polished surface, the content of the nitrogen-containing heterocyclic compound may be 10% by mass or less, 8% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, less than 1% by mass, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.1% by mass or less, less than 0.1% by mass, 0.09% by mass or less, 0.08% by mass or less, 0.07% 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, 0.008% by mass or less, 0.006% by mass or less, or 0.005% by mass or less, based on the total mass of the polishing liquid. From these viewpoints, the content of the nitrogen-containing heterocyclic compound may be 0.0001 to 10 mass %, 0.001 to 1 mass %, or 0.005 to 0.1 mass % based on the total mass of the polishing liquid.

[0048] From the viewpoint of polishing silicon-based materials at a higher polishing rate and from the viewpoint of suppressing the polishing rate of insulating materials, the content of the nitrogen-containing heterocyclic compound of this embodiment may be 0.001 parts by mass or more, 0.005 parts by mass or more, 0.008 parts by mass or more, 0.01 parts by mass or more, 0.05 parts by mass or more, 0.08 parts by mass or more, 0.1 parts by mass or more, 0.2 parts by mass or more, 0.25 parts by mass or more, 0.5 parts by mass or more, 0.8 parts by mass or more, 1 part by mass or more, 1.5 parts by mass or more, 2 parts by mass or more, or 2.5 parts by mass or more relative to 100 parts by mass of the abrasive grains. The content of the nitrogen-containing heterocyclic compound may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, 10 parts by mass or less, 8 parts by mass or less, 6 parts by mass or less, 5 parts by mass or less, less than 5 parts by mass, 4 parts by mass or less, 3 parts by mass or less, 2.5 parts by mass or less, 2 parts by mass or less, 1 part by mass or less, 0.8 parts by mass or less, 0.6 parts by mass or less, 0.5 parts by mass or less, 0.4 parts by mass or less, 0.3 parts by mass or less, or 0.25 parts by mass or less, relative to 100 parts by mass of the abrasive grains, from the viewpoint of improving the uniformity in the polished surface. From these viewpoints, the content of the nitrogen-containing heterocyclic compound may be 0.001 to 100 parts by mass, 0.01 to 50 parts by mass, 0.1 to 20 parts by mass, or 0.25 to 10 parts by mass, relative to 100 parts by mass of the abrasive grains.

[0049] When the polishing liquid according to this embodiment contains a polyether described below, the content of the nitrogen-containing heterocyclic compound may be 0.1 parts by mass or more, 0.5 parts by mass or more, 0.8 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, 4 parts by mass or more, 5 parts by mass or more, 6 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, or 65 parts by mass or more, relative to 100 parts by mass of polyether, from the viewpoint of polishing silicon-based materials at a higher polishing rate and suppressing the polishing rate of insulating materials. The content of the nitrogen-containing heterocyclic compound may be 1000 parts by mass or less, 800 parts by mass or less, 600 parts by mass or less, 400 parts by mass or less, 300 parts by mass or less, 200 parts by mass or less, 150 parts by mass or less, 100 parts by mass or less, 80 parts by mass or less, 75 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, 10 parts by mass or less, 8 parts by mass or less, 7.5 parts by mass or less, or 7 parts by mass or less, relative to 100 parts by mass of polyether, from the viewpoint of improving uniformity in the polished surface. From these viewpoints, the content of the nitrogen-containing heterocyclic compound may be 0.1 to 1000 parts by mass, 1 to 500 parts by mass, or 5 to 100 parts by mass relative to 100 parts by mass of polyether.

[0050] (water) The polishing liquid according to the present embodiment may contain water. The water is not particularly limited, and may include at least one type of water selected from the group consisting of deionized water, ion-exchanged water, pure water, and ultrapure water.

[0051] (Other additives) The polishing liquid according to this embodiment may contain components other than the abrasive grains, the nitrogen-containing heterocyclic compound, and water. Such components include polyethers, pH adjusters, anticorrosive agents, peroxides, organic solvents, surfactants, and antifoaming agents. The polishing liquid according to this embodiment may not contain at least one of these components.

[0052] [Polyether] The polishing liquid according to the present embodiment may contain polyether from the viewpoint of polishing silicon-based materials at a higher polishing rate. Polyether is a compound having two or more ether groups. The "ether group" in polyether does not include the "-O-" structure in a hydroxyl group, a carboxyl group, a carboxylate group, an ester group, a sulfo group, and a phosphate group.

[0053] Examples of polyethers include polyglycerin, polysaccharides, polyalkylene glycols, polyoxypropylene polyglyceryl ethers, polyoxyethylene polyglyceryl ethers, 1,4-di(2-hydroxyethoxy)benzene, 2,2-bis(4-polyoxyethyleneoxyphenyl)propane, 2,2-bis(4-polyoxypropyleneoxyphenyl)propane, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, polyoxyalkylene monophenyl ether, propylene glycol monophenyl ether, polyoxypropylene monomethylphenyl ether, polyethylene glycol monomethyl ether, pentaerythritol polyoxyethylene ether, ethylene glycol monoallyl ether, polyoxyethylene monoallyl ether, and alkyl glucosides. The polyether may contain polyglycerin from the viewpoint of polishing silicon-based materials at a higher polishing rate.

[0054] From the viewpoint of polishing silicon-based materials at a higher polishing rate, the polyether may contain polyglycerin having an average polymerization degree of glycerin in the following ranges. The average polymerization degree of glycerin may be 3 or more, 4 or more, 5 or more, 8 or more, or 10 or more. The average polymerization degree of glycerin may be 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, or 30 or less. From these viewpoints, the average polymerization degree of glycerin may be 3 to 100, or 5 to 60.

[0055] The weight average molecular weight of the polyether may be in the following range from the viewpoint of polishing silicon-based materials at a higher polishing rate. The weight average molecular weight may be 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more. The weight average molecular weight of the polyether may be 5000 or less, 4000 or less, 3500 or less, 3000 or less, 2500 or less, or 2000 or less. From these viewpoints, the weight average molecular weight may be 250 to 5000. The weight average molecular weight of the polyether can be measured by the same method as that of the weight average molecular weight of the cationic polymer.

[0056] The content of polyether may be in the following range based on the total mass of the polishing liquid from the viewpoint of polishing silicon-based materials at a higher polishing rate. The content of polyether may be more than 0 mass%, 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, more than 0.01 mass%, 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, 0.07 mass% or more, or 0.075 mass% or more. The content of polyether may be 10 mass% or less, 8 mass% or less, 5 mass% or less, 3 mass% or less, 2 mass% or less, 1 mass% or less, less than 1 mass%, 0.8 mass% or less, 0.5 mass% or less, 0.3 mass% or less, 0.1 mass% or less, 0.09 mass% or less, 0.08 mass% or less, or 0.075 mass% or less. From these viewpoints, the content of polyether may be more than 0 mass % and 10 mass % or less, or 0.01 to 0.3 mass %.

[0057] The content of polyether may be in the following range with respect to 100 parts by mass of abrasive grains from the viewpoint of polishing silicon-based materials at a higher polishing rate. The content of polyether may be more than 0 parts by mass, 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 37.5 parts by mass or more. The content of polyether may be 1000 parts by mass or less, 500 parts by mass or less, 200 parts by mass or less, 100 parts by mass or less, 90 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, or 37.5 parts by mass or less. From these viewpoints, the content of polyether may be more than 0 parts by mass to 1000 parts by mass or less, or 15 to 100 parts by mass.

[0058] The content of the polyether may be in the following range with respect to 100 parts by mass of the nitrogen-containing heterocyclic compound from the viewpoint of polishing silicon-based materials at a higher polishing rate. The content of the polyether may be more than 0 parts by mass, 1 part by mass or more, 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, 100 parts by mass or more, 110 parts by mass or more, 120 parts by mass or more, 130 parts by mass or more, 140 parts by mass or more, or 150 parts by mass or more. The content of the polyether may be 1000 parts by mass or less, 800 parts by mass or less, 600 parts by mass or less, 500 parts by mass or less, 400 parts by mass or less, 300 parts by mass or less, 200 parts by mass or less, 190 parts by mass or less, 180 parts by mass or less, 170 parts by mass or less, 160 parts by mass or less, or 150 parts by mass or less. From these viewpoints, the content of the polyether may be more than 0 part by mass and not more than 1000 parts by mass, or from 50 to 300 parts by mass.

[0059] [pH adjuster] The polishing liquid may contain an acid component or a base component as a pH adjuster. From the viewpoint of improving productivity, the polishing liquid may be prepared without using a pH adjuster. The acid component may be an organic acid component or an inorganic acid component.

[0060] Examples of the organic acid component include organic acids (excluding amino acids), organic acid esters, organic acid salts, amino acids, amino acid esters, and amino acid salts. Examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, 3-methylphthalic acid, 4-methylphthalic acid, 3-aminophthalic acid, 4-aminophthalic acid, 3-nitrophthalic acid, 4-nitrophthalic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, isophthalic acid, malic acid, tartaric acid, citric acid, p-toluenesulfonic acid, p-phenolsulfonic acid, methylsulfonic acid, lactic acid, itaconic acid, maleic acid, quinaldic acid, adipic acid, pimelic acid, and hydroxybenzoic acid. Examples of organic acid esters include esters of the above-mentioned organic acids. Examples of organic acid salts include ammonium salts (e.g., ammonium acetate), alkali metal salts, alkaline earth metal salts, and halides of the above-mentioned organic acids. Examples of amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. Examples of amino acid esters include esters of the above-mentioned amino acids. Examples of amino acid salts include alkali metal salts of the above-mentioned organic acids.

[0061] From the viewpoint of polishing silicon-based materials at a higher polishing rate, the organic acid component may contain at least one selected from the group consisting of an organic acid other than an amino acid and an amino acid, and may contain at least one selected from the group consisting of quinaldic acid, hydroxybenzoic acid, and glycine.

[0062] Examples of inorganic acid components include inorganic acids, ammonium salts of inorganic acids, chromic acid, etc. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, etc. Examples of ammonium salts of inorganic acids include ammonium salts of monovalent inorganic acids such as ammonium nitrate, ammonium chloride, ammonium bromide, etc.; ammonium salts of divalent inorganic acids such as ammonium carbonate, ammonium hydrogen carbonate, ammonium sulfate, ammonium persulfate, etc.; and ammonium salts of trivalent inorganic acids such as ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium borate, etc.

[0063] The content of the acid component may be in the following ranges based on the total mass of the polishing liquid. The content of the acid component may be more than 0 mass%, 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.5 mass% or more, 2 mass% or more, or 1 mass% or more. The content of the acid component may be 10 mass% or less, 5 mass% or less, 3 mass% or less, 1 mass% or less, 0.5 mass% or less, 0.1 mass% or less, 0.05 mass% or less, or 0.01 mass% or less. From these viewpoints, the content of the acid component may be 0.01 to 10 mass%, 0.05 to 5 mass%, 0.1 to 3 mass%, or 0.5 to 1 mass%.

[0064] Examples of the basic component include sodium hydroxide, ammonia (for example, aqueous ammonia), potassium hydroxide, calcium hydroxide, etc. The polishing liquid does not necessarily need to contain a basic component.

[0065] The content of the base component, based on the total mass of the polishing liquid, may be, for example, more than 0 mass%, 0.00001 mass% or more, 0.00005 mass% or more, 0.0001 mass% or more, 0.0005 mass% or more, or 0.01 mass% or more, or may be 10 mass% or less, 5 mass% or less, 1 mass% or less, 0.5 mass% or less, 0.1 mass% or less, 0.05 mass% or less, 0.01 mass% or less, 0.005 mass% or less, 0.001 mass% or less, 0.0005 mass% or less, or 0.0001 mass% or less.

[0066] (pH) The pH of the polishing liquid according to the present embodiment may be in the following ranges from the viewpoint of polishing silicon-based materials at a higher polishing rate. The pH may be 7 or less, less than 7, 6.5 or less, 6 or less, less than 6, 5.8 or less, 5.6 or less, 5.5 or less, less than 5.5, 5.4 or less, 5.2 or less, 5 or less, less than 5, 4.9 or less, or 4.8 or less. The pH may be 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more, more than 3, 3.2 or more, 3.4 or more, 3.5 or more, more than 3.5, 3.6 or more, 3.8 or more, 4 or more, more than 4, 4.1 or more, or 4.2 or more. From these viewpoints, the pH may be 1 to 7, 2 to 6, or 4 to 5. The pH can be measured by the method described in the Examples.

[0067] <How to prepare and use the polishing solution> 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), and the preparation method and method of use differ depending on the type. (a) The normal type is a polishing liquid that can be used as is without pretreatment such as dilution during polishing. (b) 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. (c) The multiple liquid type is a polishing liquid in which the components are separated into multiple liquids (e.g., a first liquid containing certain components and a second liquid containing other components) during storage or transportation, and these liquids are mixed when used.

[0068] (a) The normal type can be obtained by dissolving or dispersing abrasive grains and additives in water, which is the main dispersion medium. The preparation of the polishing liquid can be carried out using, for example, a stirrer, homogenizer, ultrasonic disperser, wet ball mill, etc. In addition, a process of micronizing the abrasive grains may be carried out during the preparation process of the polishing liquid so that the average grain size of the abrasive grains falls within a desired range. The micronization 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. On the other hand, 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.

[0069] (b) Concentrated type is diluted with water immediately before use so that the content of the ingredients is the desired content. After dilution, stirring may be performed for any length of time until the liquid properties (pH, abrasive grain size, etc.) and polishing properties (polishing speed for desired silicon-based materials, etc.) are similar to those of (a) regular type. Such (b) concentrated type reduces its volume depending on the degree of concentration, which allows for reduced storage and transportation costs.

[0070] 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 be advantageous 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 abrasive grains compared to a concentration ratio of more than 40 times.

[0071] The (c) multiple liquid type has an advantage over the (b) concentrated type in that each liquid (first liquid, second liquid, etc.) is appropriately separated to avoid aggregation of abrasive grains. Here, the components contained in each liquid are arbitrary. The (c) multiple liquid type (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). In the (c) multiple liquid type, the components of the 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. In a first embodiment of the (c) multiple liquid type, the first liquid contains abrasive grains and water, and the second liquid contains a nitrogen-containing heterocyclic compound and water. The first liquid and the second liquid may contain other components that are mixed as necessary. In this case, in order to improve the dispersibility of the abrasive grains in the first liquid, an arbitrary acid component or base component may be added to the first liquid to adjust the pH.

[0072] (c) A multi-liquid type polishing liquid is useful for a combination of components that, when mixed, tend to have their polishing properties deteriorated in a relatively short time due to agglomeration of abrasive grains, etc. In order to reduce storage and transportation costs, at least one of the liquids (first liquid, second liquid, etc.) may be a concentrated type. In this case, 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 polishing properties similar to those of the (a) normal type polishing liquid.

[0073] <Polishing method> The polishing method according to this embodiment may include a polishing step of polishing a member to be polished that contains a silicon-based material using the above-mentioned polishing liquid, or may include a polishing step of polishing a member to be polished that contains a silicon-based material using a polishing liquid obtained by mixing the slurry and the additive liquid in the above-mentioned polishing liquid set.

[0074] The member to be polished contains a silicon-based material. The member to be polished may further contain an insulating material (e.g., silicon nitride). The polishing method according to this embodiment may include a polishing step of polishing the member to be polished using, for example, the above-mentioned polishing liquid or a polishing liquid obtained by mixing the slurry and the additive liquid in the above-mentioned polishing liquid set. According to the polishing method according to this embodiment, the silicon-based material can be polished at a high polishing rate.

[0075] Examples of methods for producing silicon-based materials and insulating materials include CVD methods such as low-pressure CVD, subatmospheric pressure CVD, and plasma CVD; and spin-coating methods in which a liquid source is applied to a rotating substrate.

[0076] The silicon-based material and the insulating material may each be a single material or a plurality of materials. When a plurality of materials are exposed on the surface to be polished, they can be regarded as the silicon-based material and the insulating material. The silicon-based material and the insulating material may be in the form of a film, and may be an amorphous silicon film, a polysilicon film, a single crystal silicon film, a silicon oxide film, a silicon nitride film, or the like.

[0077] The polishing method according to this embodiment may be a method for polishing a substrate. The substrate has, for example, a member containing a silicon-based material. The substrate may have, for example, a member containing a silicon-based material and a member containing an insulating material. According to this embodiment, a method for polishing a substrate containing a silicon-based material and an insulating material can be provided, which includes a polishing step of polishing the substrate using the above-mentioned polishing liquid or a polishing liquid obtained by mixing the slurry and the additive liquid in the above-mentioned polishing liquid set.

[0078] The substrate to be polished may be a substrate, for example, a substrate in which a member containing a silicon-based material and a member containing an insulating material are formed on a substrate used in the manufacture of a semiconductor device (e.g., a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc. are formed).

[0079] In the polishing process, for example, the polishing surface of the substrate is pressed against the polishing pad of the polishing platen, the polishing liquid is supplied between the substrate and the polishing pad, and the substrate and the polishing platen are moved relative to each other to polish the substrate. In the polishing process, for example, at least a part of the silicon-based material in the substrate is removed by polishing.

[0080] In the polishing method according to the present embodiment, a general polishing device having a holder capable of holding a substrate (e.g., a semiconductor substrate) having a surface to be polished and a polishing platen to which a polishing pad can be attached can be used as the polishing device. A motor capable of changing the rotation speed is attached to each of the holder and the polishing platen. As the polishing device, for example, a polishing device manufactured by APPLIED MATERIALS, product name: Reflexion; and a polishing device manufactured by Ebara Corporation, product name: F-REX300X can be used.

[0081] As the polishing pad, general nonwoven fabric, foam, non-foam, etc. can be used. As the material of the polishing pad, polyurethane, acrylic resin, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly-4-methylpentene, cellulose, cellulose ester, polyamide (e.g., nylon and aramid), polyimide, polyimideamide, polysiloxane copolymer, oxirane compound, phenol resin, polystyrene, polycarbonate, epoxy resin, etc. can be used. As the material of the polishing pad, particularly from the viewpoint of polishing speed and flatness, foamed polyurethane and non-foamed polyurethane may be used. The polishing pad may be grooved so that the polishing liquid can be collected.

[0082] There are no restrictions on the polishing conditions, but the rotation speed (number of revolutions) of the polishing plate should be set to 200 min so that the substrate does not pop out. -1 The polishing pressure (processing load) applied to the substrate may be 100 kPa or less from the viewpoint of sufficiently suppressing the occurrence of polishing scratches. During polishing, the polishing liquid may be continuously supplied to the polishing pad by a pump or the like. There is no limit to the amount of supply, but the surface of the polishing pad may be constantly covered with the polishing liquid.

[0083] After polishing, the substrate may be thoroughly washed in running water to remove particles adhering to the substrate. For washing, a cleaning chemical such as dilute hydrofluoric acid or ammonia water may be used in addition to pure water, and a brush may be used to improve the efficiency of washing. After washing, water droplets adhering to the substrate may be brushed off using a spin dryer or the like, and then the substrate may be dried.

[0084] The polishing liquid and polishing method according to the present embodiment may be applied not only to film-like objects to be polished, but also to various substrates made of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, etc.

[0085] The polishing liquid and polishing method according to the present embodiment can be used not only in the manufacture of semiconductor devices, but also in the manufacture of image display devices such as TFT liquid crystals and organic EL; optical components such as photomasks, lenses, prisms, optical fibers and single crystal scintillators; optical elements such as optical switching elements and optical waveguides; light-emitting elements such as solid-state lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.

[0086] <Manufacturing method etc.> The component manufacturing method according to the present embodiment includes a component manufacturing step of obtaining a component using a base (a member to be polished) 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). As one aspect of the component manufacturing method according to the present embodiment, in the electronic component manufacturing method according to the present embodiment, an electronic component is obtained using a base polished by the polishing method according to the present embodiment. As one aspect of the component manufacturing method according to the present embodiment, in the semiconductor component manufacturing method according to the present embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a base polished by the polishing method according to the present embodiment. 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.

[0087] The manufacturing method of the component according to the present embodiment may include, as one aspect of the component manufacturing process, a singulation process for singulating a base (a 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). As one aspect of the manufacturing method of the component according to the present embodiment, the manufacturing method of the electronic component 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). As one aspect of the manufacturing method of the component according to the present embodiment, the manufacturing method of the semiconductor component 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).

[0088] The manufacturing method of the component according to the present 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 the present embodiment to another connected body. The connected body to be connected to the base polished by the polishing method according to the present embodiment is not particularly limited, and may be the base polished by the polishing method according to the present embodiment, or may be a connected body different from the base polished by the polishing method according to the present embodiment. In the connection process, 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 (conductive member, etc.). The connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0089] 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 connected 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.

[0090] The device according to this embodiment (for example, an electronic device such as a semiconductor device) comprises at least one selected from the group consisting of a substrate polished by the polishing method according to this embodiment and a part according to this embodiment. EXAMPLES

[0091] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0092] (Abrasive grain) [Cerium oxide particles] 40 kg of commercially available cerium carbonate hydrate was placed in an alumina container and calcined in air at 830°C for 2 hours to obtain 20 kg of yellowish white powder. The phase of this powder was identified by X-ray diffraction and confirmed to be cerium oxide. 20 kg of the obtained cerium oxide powder was dry-pulverized using a jet mill to obtain cerium oxide powder containing cerium oxide particles.

[0093] <Preparation of polishing solution> The polishing liquids used in each example and comparative example were prepared as follows: based on the total mass of the polishing liquid, they contained 2% by mass of cerium oxide particles as abrasive grains, 2-hydroxypyridine-N-oxide in the amounts shown in Table 1, and 0.075% by mass of polyglycerin, with the balance being pure water. Specifically, water was added to the above-mentioned storage liquid for cerium oxide slurry and diluted 5 to 10 times to obtain a slurry containing cerium oxide particles as abrasive grains. Next, each component other than the abrasive grains was dissolved in pure water to obtain an additive solution. Then, the above slurry and the above additive solution were mixed and stirred to prepare a polishing liquid.

[0094] The particle size of the abrasive grains in the prepared polishing liquid was measured using a laser diffraction / scattering particle size distribution measuring device Microtrac MT3300EX II (manufactured by Microtrac Bell Co., Ltd.). Specifically, the polishing liquid and water were mixed so that the DV value (Diffraction Volume) displayed on the software during measurement was 0.0010 to 0.0011, and the particle size of the abrasive grains was measured under the following measurement conditions. The measurement results of D50 (average particle size), D90, D99, and MV (volume average diameter) of the abrasive grains are shown in Table 1.

[0095] (Measurement conditions) Particle permeability: Transmission Particle refractive index: 2.2 Particle shape: Non-spherical Solvent: Water Solvent refractive index: 1.333

[0096] (pH measurement) The pH of the polishing liquid was measured under the following conditions. The results are shown in each table. Measurement temperature: 25°C Measuring device: Trade name of Horiba, Ltd.: Model (D-71) Measurement method: After calibrating the pH meter at three points using phthalate pH standard solution (pH: 4.01), neutral phosphate pH standard solution (pH: 6.86), and borate pH standard solution (pH: 9.18) as pH standard solutions, the electrode of the pH meter was placed in the polishing liquid, and after more than 2 minutes had elapsed and it had stabilized, the pH was measured using the above measuring device. The measurement results are shown in Table 1.

[0097] <Evaluation of polishing characteristics> Using the polishing liquids of each of the Examples and Comparative Examples, films to be polished (amorphous silicon film (a-Si film), silicon oxide film (TEOS film), silicon nitride film (SiN film)) formed on silicon substrates were polished under the following polishing conditions.

[0098] (polishing conditions) Polishing device: F-REX300X (manufactured by Ebara Corporation) Polishing liquid flow rate: 250mL / min Polishing pad: DuPont IK4250H Grinding pressure: 27.6kPa (4psi) Plate rotation speed: 93 rpm Polishing table and head rotation speed: Polishing table / head = 125 / 126 rpm Polishing time: 20 seconds Cleaning: After the CMP process, the substrate was cleaned with water while applying ultrasonic waves, and then dried with a spin dryer.

[0099] <Polishing characteristics evaluation> Using an optical interference film thickness measuring device (Nova Ltd., product name: nova i500), the amount of film thickness change at multiple measurement points in the inner region remaining after excluding the outer periphery of 3 mm from the outer periphery of each of the amorphous silicon film, silicon oxide film, and silicon nitride film was measured, and the polishing rate at each measurement point was obtained. The measurement points were -147 mm, -145 mm, -140 mm, -135 mm, ... (5 mm intervals) ..., -10 mm, and -5 mm from the center point in the diameter direction passing through the center point of the inner region, the center point, and +5 mm, +10 mm, ... (5 mm intervals) ..., +135 mm, +140 mm, +145 mm, and +147 mm from the center point. The average polishing rate is shown in Table 1. In addition, the polishing speed ratio of the amorphous silicon film to the silicon oxide film (a-Si film / TEOS film) and the polishing speed ratio of the amorphous silicon film to the silicon nitride film (a-Si film / SiN film) were calculated. The polishing speed ratios are shown in Table 1. After calculating the average and standard deviation of the polishing speeds, the numerical value (unit: %) of "NU = standard deviation / average value" was calculated. As an index of in-plane uniformity, the numerical value obtained by dividing NU of each Example by NU of Comparative Example 1 is shown in Table 1.

[0100] [Table 1]

Claims

1. A polishing liquid for polishing a member to be polished that contains a silicon-based material (excluding silicon nitride), comprising: The abrasive grains and a nitrogen-containing heterocyclic compound are contained, The abrasive grains contain a cerium-based compound, the nitrogen-containing heterocyclic compound contains an oxygen atom, the oxygen atom is bonded to a nitrogen atom constituting a heterocycle.

2. The polishing liquid according to claim 1 , wherein the nitrogen-containing heterocyclic compound has a hydroxy group.

3. A polishing liquid for polishing a member to be polished that contains a silicon-based material (excluding silicon nitride), comprising: The abrasive grains and a nitrogen-containing heterocyclic compound are contained, The abrasive grains contain a cerium-based compound, The polishing liquid, wherein the nitrogen-containing heterocyclic compound has a hydroxy group.

4. The polishing liquid according to any one of claims 1 to 3, wherein the abrasive grains contain cerium oxide.

5. 4. The polishing liquid according to claim 1, wherein the nitrogen-containing heterocyclic compound contains one nitrogen atom as a heteroatom.

6. 4. The polishing liquid according to claim 1, wherein the number of members of the heterocycle of the nitrogen-containing heterocyclic compound is 6.

7. The polishing liquid according to claim 2 or 3, wherein the hydroxy group is bonded to a carbon atom constituting a heterocycle.

8. The polishing liquid according to claim 7 , wherein the carbon atom is bonded to a nitrogen atom constituting the heterocycle.

9. 4. The polishing liquid according to claim 1, wherein the content of the nitrogen-containing heterocyclic compound is more than 0.015 mass % based on the total mass of the polishing liquid.

10. 4. The polishing liquid according to claim 1, wherein the content of the nitrogen-containing heterocyclic compound is more than 0.035 mass % based on the total mass of the polishing liquid.

11. 4. The polishing liquid according to claim 1, wherein the silicon-based material comprises at least one material selected from the group consisting of amorphous silicon, polysilicon, and single crystal silicon.

12. 4. The polishing liquid according to claim 1, wherein the polished member further contains silicon nitride.

13. 4. A polishing method comprising the step of polishing a workpiece containing a silicon-based material with the polishing liquid according to claim 1.

14. A method for producing a semiconductor device, comprising obtaining a semiconductor device by using a polished member polished by the polishing method according to claim 13.

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