WO2023140146A1

WO2023140146A1 - Polishing composition, concentrated solution of polishing composition, and polishing method

Info

Publication number: WO2023140146A1
Application number: PCT/JP2023/000300
Authority: WO
Inventors: 修後藤; 大輝 ▲高▼間; 優己田中; 公亮土屋
Original assignee: 株式会社フジミインコーポレーテッド
Priority date: 2022-01-21
Filing date: 2023-01-10
Publication date: 2023-07-27
Also published as: TW202342689A; JPWO2023140146A1

Abstract

The present invention provides a means which makes it possible to polish a target object at a high polishing rate and also makes it possible to maintain the surface quality of the polished target object at a good level.　The present invention is a polishing composition comprising abrasive grains and a basic compound, in which the basic compound comprises ammonia and a piperazine compound, and the content ratio C1 of the piperazine compound represented by formula (1) is more than 0% and 5.5% or less when the content of the ammonia in the polishing composition is defined as A1 (unit: % by mass) and the content of the piperazine compound in the polishing composition is defined as B1 (unit: % by mass).

Description

Polishing composition, concentrate of polishing composition, and polishing method

The present invention relates to a polishing composition, a polishing composition concentrate, and a polishing method.

In order to achieve higher integration and higher speed of integrated circuits such as ULSI used in computers, the design rules of semiconductor devices are becoming finer year by year. Along with this, the number of cases where finer surface defects adversely affect the performance of semiconductor devices is increasing, and the importance of managing nano-order defects, which have not been regarded as a problem in the past, is increasing.

A surface defect inspection device is used to manage surface defects of single crystal silicon substrates (silicon wafers). Defects detected by the surface defect inspection apparatus include foreign matter and residues on the single crystal silicon substrate that have not been completely removed in the polishing, rinsing, and cleaning processes. A typical surface defect inspection apparatus irradiates the surface of a single crystal silicon substrate with light such as a laser beam, receives the reflected light as a signal, and analyzes it to detect the presence or absence of defects and their sizes.

When a mirror-finished surface of a single crystal silicon substrate after polishing or after polishing and rinsing is irradiated with strong light, cloudiness may be seen due to irregular reflection caused by extremely fine roughness of the surface of the single crystal silicon substrate. This cloudiness is called haze, and haze can be used as a measure of surface roughness of a single crystal silicon substrate. If there is haze on the surface of the single-crystal silicon substrate, diffusely reflected light caused by the haze may become noise and interfere with defect detection by a surface defect inspection apparatus. Therefore, as the size of defects to be detected, that is, the size of defects to be managed becomes smaller, the need to reduce haze increases.

As a technique capable of achieving both a reduction in haze and a high polishing rate of a single crystal silicon substrate (silicon wafer), for example, JP-A-2016-122804 discloses a polishing liquid composition for silicon wafers containing silica particles (component A), hydroxylamine (component B), and a water-soluble polymer compound (component C), wherein the mass ratio of hydroxylamine to component C (mass of hydroxylamine/mass of component C) is within a specific range.

However, with the technique described in JP-A-2016-122804, it is still insufficient to achieve both reduction of haze and high polishing rate.

Therefore, an object of the present invention is to provide means capable of polishing an object to be polished at a high polishing rate and capable of maintaining good surface quality of the object to be polished after polishing.

In order to solve the above problems, the present inventors have accumulated extensive research. As a result, the present inventors have found that the above problems can be solved by a polishing composition having the following composition, and have completed the present invention.

That is, the first embodiment of the present invention includes abrasive grains and a basic compound, wherein the basic compound contains ammonia and a piperazine compound, and the content C1 of the piperazine compound represented by the following formula (1) is more than 0% and 5.5% or less, where A1 (unit: mass%) is the content of the ammonia in the polishing composition and B1 (unit: mass%) is the content of the piperazine compound in the polishing composition. A polishing composition.

A second embodiment of the present invention includes an abrasive grain and a basic compound, wherein the basic compound contains ammonia and an amine compound A having two or more nitrogen atoms and a pKa higher than that of the ammonia. When the content of the ammonia in the polishing composition is A2 (unit: mass %) and the content of the amine compound A in the polishing composition is B2 (unit: mass %), the content C2 of the amine compound A represented by the following formula (2) is 0. % more than 5.5% or less.

A third embodiment of the present invention comprises an abrasive grain and a basic compound, wherein the basic compound contains ammonia and an amine compound B having one nitrogen atom and a pKa higher than that of the ammonia, the amine compound B is a secondary amine or a tertiary amine, and the content of the ammonia in the polishing composition is A3 (unit: mass %), and the content of the amine compound B in the polishing composition is B3 (unit: mass %). ) is more than 0% and 35% or less in the polishing composition.

A fourth aspect of the present invention is a concentrated liquid of the polishing composition according to the first to third aspects.

A fifth aspect of the present invention is a polishing method comprising polishing an object to be polished using the polishing compositions according to the first to third aspects.

A first embodiment of the present invention comprises abrasive grains and a basic compound, wherein the basic compound contains ammonia and a piperazine compound, and when the content of the ammonia in the polishing composition is A1 (unit: mass %) and the content of the piperazine compound in the polishing composition is B1 (unit: mass %), the content C1 of the piperazine compound represented by the following formula (1) is more than 0% and 5.5% or less. composition.

The polishing composition according to the present invention having such a configuration can polish an object to be polished at a high polishing rate, and can maintain good surface quality of the object to be polished after polishing.

The mechanism by which the above effects are obtained by the polishing composition according to the present invention is believed to be as follows. However, the mechanism described below is merely speculation, and does not limit the scope of the present invention.

Increasing the etching rate of the object to be polished is one of the effective means for rapidly polishing the object to be polished. In the present invention, the piperazine compound, the amine compound A, or the amine compound B is added to the polishing composition so that the contents C1 to C3 represented by the above formulas (1) to (3) satisfy the above ranges, whereby the ammonia effectively interacts with the piperazine compound, the amine compound A, or the amine compound B, and the etching rate becomes moderate. It is believed that this allows the object to be polished to be polished at a high polishing rate. The surface quality of the polished surface can be improved by adding a water-soluble polymer, a surfactant, or the like to the polishing composition to protect the substrate. In the present invention, by adding the piperazine compound, the amine compound A, or the amine compound B to the polishing composition so that the contents C1 to C3 represented by the above formulas (1) to (3) satisfy the above ranges, it is believed that the polishing rate can be improved without impairing the effect of using the water-soluble polymer, surfactant, etc. (effect of improving the quality of the polished surface).

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the claims. The embodiments described herein can be combined arbitrarily to form other embodiments. Hereinafter, the polishing composition according to the first embodiment of the present invention is also referred to as "first polishing composition", the polishing composition according to the second embodiment of the present invention is also referred to as "second polishing composition", and the polishing composition according to the third embodiment of the present invention is also referred to as "third polishing composition". Further, the polishing compositions according to the first to third embodiments of the present invention are collectively referred to as "polishing compositions according to the present invention". Furthermore, the ammonia contents A1, A2, and A3 in the above formulas (1) to (3) are collectively referred to as "ammonia content A", and the contents C1, C2, and C3 are collectively referred to as "content C".

In the present specification, for the sake of convenience, the first to third polishing compositions are separately described, but the polishing composition according to the present invention may be used in combination of two or three of the piperazine compound, amine compound A, and amine compound B. At this time, each compound is added so that the contents C1, C2, and C3 represented by the above formulas (1) to (3) respectively satisfy the above numerical ranges. For example, when a piperazine compound and an amine compound B are used in combination, the amount of each compound added is adjusted so that the content C1 of the piperazine compound represented by the above formula (1) satisfies the range of more than 0% and 5.5% or less, and the content C3 of the amine compound B satisfies the range of more than 0% and 35% or less.

In this specification, unless otherwise specified, operations and measurements of physical properties are performed under conditions of room temperature (20°C or higher and 25°C or lower)/relative humidity of 40% RH or higher and 50% RH or lower.

[Abrasive]
Polishing compositions according to some embodiments of the present invention comprise abrasive grains. Abrasive grains serve to mechanically polish the surface of an object to be polished. The material and properties of the abrasive grains are not particularly limited, and can be appropriately selected according to the intended use and mode of use of the polishing composition. Examples of abrasive grains include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include particles made of oxides such as silica, alumina, cerium oxide, chromium oxide, titanium dioxide, zirconium oxide, magnesium oxide, manganese dioxide, zinc oxide, and red iron oxide; particles made of nitrides such as silicon nitride and boron nitride particles; particles made of carbides such as silicon carbide and boron carbide; particles made of diamond; Specific examples of organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles (here, (meth)acrylic acid refers to acrylic acid and methacrylic acid comprehensively), polyacrylonitrile particles, and the like. Such abrasive grains may be used singly or in combination of two or more.

The polishing composition according to some embodiments of the present invention preferably contains silica as abrasive grains. Specific examples of silica include colloidal silica, fumed silica, precipitated silica, and the like. Silica can be used singly or in combination of two or more. Colloidal silica is particularly preferred because it is less likely to cause scratches on the surface of the object to be polished and can exhibit good polishing performance (such as performance to reduce surface roughness). As colloidal silica, for example, colloidal silica produced by ion exchange method using water glass (sodium silicate) as a raw material, and colloidal silica produced by alkoxide method (colloidal silica produced by hydrolytic condensation reaction of alkoxysilane) can be preferably employed. Colloidal silica can be used singly or in combination of two or more.

The true specific gravity of silica is preferably 1.5 or more, more preferably 1.6 or more, and still more preferably 1.7 or more. Although the upper limit of the true specific gravity of silica is not particularly limited, it is typically 2.3 or less, for example 2.2 or less. As the true specific gravity of silica, a value measured by a liquid replacement method using ethanol as a replacement liquid can be adopted.

The shape of colloidal silica is not particularly limited, and may be spherical or non-spherical. Specific examples of the non-spherical shape include polygonal prisms such as triangular prisms and square prisms, columnar shapes, bale shapes in which the central portion of the column swells more than the ends, donut shapes in which the central portion of the disc penetrates, plate shapes, so-called cocoon shapes with a constriction in the central portion, so-called associative spherical shapes in which multiple particles are integrated, so-called confetti shapes with multiple projections on the surface, rugby ball shapes, and various other shapes, but are not particularly limited.

Although not particularly limited, the average value of the major axis/minor axis ratio (average aspect ratio) of the abrasive grains is theoretically 1.0 or more, preferably 1.05 or more, and more preferably 1.1 or more. A higher polishing rate can be achieved by increasing the average aspect ratio. Also, the average aspect ratio of the abrasive grains is preferably 3.0 or less, more preferably 2.0 or less, and still more preferably 1.5 or less from the viewpoint of reducing scratches.

The shape (outer shape) and average aspect ratio of abrasive grains can be grasped, for example, by electron microscope observation. As a specific procedure for grasping the average aspect ratio, for example, using a scanning electron microscope (SEM), for a predetermined number (for example, 200 pieces) of silica particles that can recognize the shape of independent particles, draw a minimum rectangle circumscribing each particle image. Then, for the rectangle drawn for each particle image, the value obtained by dividing the length of the long side (the value of the major axis) by the length of the short side (the value of the minor axis) is calculated as the major axis/minor axis ratio (aspect ratio). The average aspect ratio can be obtained by arithmetically averaging the aspect ratios of the predetermined number of particles.

The abrasive grains contained in the polishing composition may be in the form of primary particles, or may be in the form of secondary particles in which a plurality of primary particles are associated. Further, the abrasive grains in the form of primary particles and the abrasive grains in the form of secondary particles may be mixed. In a preferred embodiment, at least part of the abrasive grains are contained in the polishing composition in the form of secondary particles.

Here, the surface of the object to be polished (especially a silicon wafer) is generally finished to a high-quality mirror surface through a lapping process and a polishing process. The polishing process is usually composed of a plurality of polishing processes including a preliminary polishing process (preliminary polishing process, a polishing process before the final polishing process) and a final polishing process (final polishing process). For example, a polishing composition with high processing power (polishing power) is used in the step of roughly polishing an object to be polished (especially a silicon wafer) (e.g., preliminary polishing step), and a polishing composition with low polishing power is used in the step of finely polishing (e.g., final polishing step). As described above, the polishing composition used has different polishing characteristics required for each polishing process, and thus the particle size and content of silica contained in the polishing composition may be different depending on the stage of the polishing process in which the polishing composition is used.

At this time, the increase in the particle size of the abrasive grains makes it easier to mechanically polish the surface of the object to be polished, and tends to improve the polishing rate. On the other hand, the reduction in the particle size of the abrasive grains tends to make it easier to reduce the haze of the polished object.

The average primary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and particularly preferably 20 nm or more (for example, more than 20 nm). Further, the average primary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is, for example, 100 nm or less, may be 80 nm or less, preferably 60 nm or less, more preferably 50 nm or less, more preferably 45 nm or less, and particularly preferably 43 nm or less. In some aspects, the average primary particle size of the abrasive grains may be less than 40 nm, less than 38 nm, less than 35 nm, less than 32 nm, or less than 30 nm.

The average secondary particle size of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is preferably 10 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, and particularly preferably 35 nm or more. In some aspects, the average secondary particle size of the abrasive grains may be 40 nm or more, 42 nm or more, or 44 nm or more. Further, the average secondary particle diameter of the abrasive grains contained in the polishing composition according to some embodiments of the present invention is, for example, 250 nm or less, may be 180 nm or less, may be 150 nm or less, or may be 100 nm or less. It is preferably 90 nm or less, and further preferably 80 nm or less. In some aspects, the average secondary particle size of the abrasive grains may be 70 nm or less, 60 nm or less, or 50 nm or less.

The preferred ranges of the average primary particle size and average secondary particle size of the abrasive grains are also the preferred ranges of the average primary particle size and average secondary particle size of the abrasive grains contained in the raw material dispersion used for the preparation.

As used herein, the average primary particle size refers to the particle size (BET particle size) calculated from the specific surface area (BET value) measured by the BET method, average primary particle size (nm) = 6000/(true density (g/cm ³ ) x BET value (m ² /g)). The specific surface area can be measured using, for example, "Flow Sorb II 2300" manufactured by Micromeritex. The average secondary particle size of the abrasive grains is measured, for example, by a dynamic light scattering method, and can be measured using, for example, "Nanotrack (registered trademark) UPA-UT151" manufactured by Nikkiso Co., Ltd.

In addition, as described above, the polishing composition to be used has different polishing characteristics required for each polishing process, so the content of abrasive grains in the polishing composition may also vary depending on the stage of the polishing process in which the polishing composition is used.

At this time, the polishing rate for the surface of the object to be polished tends to improve due to the increase in the content of abrasive grains. On the other hand, a decrease in the content of abrasive grains tends to improve the dispersion stability of the polishing composition and reduce the residue of abrasive grains on the polished surface.

When the polishing composition according to some embodiments of the present invention is in the state of a concentrated liquid diluted with a dispersion medium or the like and used for polishing, the content of abrasive grains in the concentrated liquid is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.025% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. It is more particularly preferred that the content is 3% by mass or more, most preferably 3% by mass or more. In this case, the content of abrasive grains in the concentrated liquid of the polishing composition is not particularly limited, but from the viewpoint of storage stability, filterability, etc., it is preferably 50% by mass or less, more preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 9% by mass or less.

In addition, when the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of abrasive grains in the polishing composition is not particularly limited, but from the viewpoint of further improving the polishing rate, it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.025% by mass or more, and particularly preferably 0.1% by mass or more. In this case, the content of abrasive grains in the polishing composition is not particularly limited, but is, for example, less than 10% by mass, may be less than 7% by mass, may be 5% by mass or less, may be 2% by mass or less, is preferably less than 1% by mass, more preferably 0.8% by mass or less, further preferably 0.6% by mass or less, particularly preferably 0.4% by mass or less, and most preferably 0.3% by mass or less.

When the above-mentioned polishing composition is used as a diluted solution, the preferable adjustment of the content of abrasive grains is preferably carried out by diluting the concentrated solution of the polishing composition with a dispersion medium such as water or a solution or dispersion containing any polishing aid.

The polishing composition according to some embodiments of the present invention may contain silica and abrasive grains other than silica. However, when the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of the other abrasive grains is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less, relative to the total mass of silica and other abrasive grains. The most preferable form is a form in which the content of other abrasive grains is 0% by mass, that is, no abrasive grains other than silica are contained.

[Basic compound]
In some embodiments of the invention, the polishing composition comprises a basic compound. Here, the basic compound refers to a compound having a function of increasing the pH of the polishing composition when added to the polishing composition. The basic compound has the function of chemically polishing the surface of the object to be polished by etching and the function of improving the dispersion stability of the abrasive grains. Basic compounds can also be used as pH adjusters.

The basic compound contained in the first polishing composition according to the present invention contains ammonia and a piperazine compound, and is characterized in that the content C1 of the piperazine compound represented by the above formula (1) is more than 0% and 5.5% or less.

The basic compound contained in the second polishing composition according to the present invention contains ammonia and an amine compound A having two or more nitrogen atoms and a pKa higher than that of ammonia, and is characterized in that the content C2 of the amine compound A represented by the above formula (2) is more than 0% and 5.5% or less.

The basic compound contained in the third polishing composition according to the present invention contains ammonia and an amine compound B having one nitrogen atom and a higher pKa than ammonia, the amine compound B is a secondary amine or a tertiary amine, and is characterized in that the content C3 of the amine compound B represented by the above formula (3) is more than 0% and 35% or less.

Here, the acid dissociation constant (pKa) means the negative common logarithm (reciprocal logarithm) of the equilibrium constant Ka in the dissociation reaction in which hydrogen ions are released from the acid. The acid dissociation constant of a base is the acid dissociation constant of the conjugate acid of that base. In this specification, the pKa of the amine compounds (amine compound A and amine compound B) employs a value calculated from the neutralization titration curve of the amine compound. More specifically, the pKa employs a value calculated from a neutralization titration curve of an amine compound measured by the method described in Examples. The pKa of ammonia calculated by this method is 9.35.

When the amine compound has multiple pKas, the highest pKa among the multiple pKas is taken as the pKa of the compound. If the amine compound has a single pKa, then that single pKa is the pKa of the compound.

<Ammonia>
Polishing compositions according to some embodiments of the present invention contain ammonia as a basic compound. When the polishing composition does not contain ammonia, that is, when the content of ammonia is 0% by mass, the etching rate decreases.

As long as the content C of the piperazine compound or amine compound represented by the above formulas (1) to (3) satisfies the above range, the content A of ammonia in the polishing composition is not particularly limited. However, when the polishing composition according to some embodiments of the present invention is in a concentrated liquid state, the content A of ammonia in the concentrated liquid is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.05% by mass or more, relative to the total mass of the concentrated liquid of the polishing composition. Further, when the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid, the ammonia content A is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.2% by mass or less, relative to the total mass of the concentrated liquid of the polishing composition.

When the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content A of ammonia in the polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, and even more preferably 0.001% by mass or more, relative to the total mass of the polishing composition. Further, when the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the ammonia content A is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, relative to the total mass of the polishing composition. In addition, when the polishing composition according to some embodiments of the present invention contains an ammonium salt such as ammonium carbonate or ammonium hydrogen carbonate, which will be described later, the content A of ammonia includes the content of ammonia obtained by reacting ammonium ions derived from the ammonium salt with hydroxide ions.

That is, when the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of ammonia in the polishing composition is preferably 0.0001% by mass or more and 1% by mass or less, more preferably 0.0005% by mass or more and 0.5% by mass or less, and even more preferably 0.001% by mass or more and 0.1% by mass or less.

<Piperazine compound>
A first polishing composition according to the present invention contains a piperazine compound. The piperazine compound has a role of oxidizing the surface of the object to be polished (particularly a silicon wafer), and when added to the polishing composition in a range where the content C1 represented by the following formula (1) is more than 0% and 5.5% or less, etching of the object to be polished can be efficiently advanced and the polishing rate can be improved.

In the above formula (1), A1 is the ammonia content (unit: mass%) in the first polishing composition, and B1 is the piperazine compound content (unit: mass%) in the polishing composition.

When the piperazine compound content C1 is 0%, that is, when the polishing composition does not contain a piperazine compound, the polishing rate decreases. On the other hand, when the content C1 of the piperazine compound exceeds 5.5%, the etching rate is suppressed by the piperazine compound, resulting in a decrease in the polishing rate. The piperazine compound content C1 is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1.0% or more. The piperazine compound content C1 is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly preferably 3.0% or less.

That is, the content C1 of the piperazine compound is preferably 0.1% or more and 5.0% or less, more preferably 0.5% or more and 4.5% or less, further preferably 1.0% or more and 4.0% or less, and particularly preferably 1.0% or more and 3.0% or less.

The piperazine compound is not particularly limited as long as it is a compound having a piperazine skeleton (piperazine ring). Specific examples of piperazine compounds include anhydrous piperazine, piperazine hexahydrate, 1-methylpiperazine, 2-methylpiperazine, 1-ethylpiperazine, 2-ethylpiperazine, 1-(n-propyl)piperazine, 2-(n-propyl)piperazine, 1-isopropylpiperazine, 1-allylpiperazine, 1-(n-butyl)piperazine, 1-isobutylpiperazine. , 1-hydroxyethoxyethylpiperazine, 1-phenylpiperazine, 1-aminopiperazine, 1-amino-4-methylpiperazine, 1-(2-hydroxyethyl)piperazine, 1-piperazineethylcarboxylate, 1-formylpiperazine, 1-acetylpiperazine, 1-cyclopentylpiperazine, 1-cyclohexylpiperazine, 1-(2-methoxyethyl)piperazine, 1-piperonylpiperazine Lazin, 1-(diphenylmethyl)piperazine, 2-piperazinone, 1-methyl-3-phenylpiperazine, 1,4-bis(3-aminopropyl)piperazine, 1-(2-dimethylaminoethyl)-4-methylpiperazine, 1-(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, 1,4-dimethylpiperazine, 2,5-dimethylpiperazine, 2,6-dimethyl Piperazine, 1,4-diethylpiperazine, 1,4-dimethylpiperazin-2-one, 1,4-diethylpiperazin-2-one, 1,4-diformylpiperazine, 1-(4-aminophenyl)-4-methylpiperazine, 1,4-diacetyl-2,5-piperazinedione, 1-methyl-4-(1,4'-bipiperazin-4-yl)piperazine, 1-(4 -aminophenyl)-4-(4-methoxyphenyl)piperazine, 1,4-dimethylpiperazine-2,3-dione, 2-piperazinecarboxylic acid and the like. These piperazine compounds can be used singly or in combination of two or more.

Among these piperazine compounds, at least one selected from the group consisting of 1-methylpiperazine, 1-(2-aminoethyl)piperazine, 1,4-dimethylpiperazine, and 1,4-bis(3-aminopropyl)piperazine is preferred.

The content B1 of the piperazine compound in the first polishing composition is not particularly limited as long as the content C1 of the piperazine compound represented by the above formula (1) is more than 0% and 5.5% or less.

However, when the first polishing composition according to the present invention is in the form of a concentrate, the content B1 of the piperazine compound in the concentrate is preferably 0.000001% by mass or more, more preferably 0.00001% by mass or more, and particularly preferably 0.00005% by mass or more, relative to the total mass of the concentrate of the first polishing composition. Further, when the first polishing composition according to the present invention is in the form of a concentrated liquid, the content B1 of the piperazine compound is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and particularly preferably 0.008% by mass or less, relative to the total mass of the concentrated liquid of the first polishing composition.

That is, if the first polishing composition according to the present invention is the condition of the concentrated solution, the content B1 of the piperadin compound in the polishing composition is preferably 0.001 % % by mass or less of 0.1 % by mass of 0.001001 % by mass, 0.001 % % by mass. It is more preferable to be 1 % by mass or less, and it is particularly preferable to be 0.00005 % by mass or less of 0.008 % by mass or less.

Further, if the first polishing composition according to the present invention is in the diluted liquid, the content B1 of the piperadin compound in the polishing composition is preferably 0.001 % by mass or more, compared to the total amount of the first polishing composition, and it is more preferable to be 0.0000,000 % by mass or more. It is even more preferable to be 001 % by mass or more, and it is particularly preferable to be 0.00004 % by mass or more. Further, when the first polishing composition according to the present invention is in the form of a diluted solution, the content B1 of the piperazine compound is, for example, 0.1% by mass or less, may be 0.05% by mass or less, preferably 0.01% by mass or less, more preferably 0.005% by mass or less, further preferably 0.001% by mass or less, and particularly preferably 0.0005% by mass or less, relative to the total mass of the first polishing composition.

That is, when the first polishing composition according to the present invention is in the form of a diluted solution, the content B1 of the piperazine compound in the first polishing composition is preferably 0.0000001% by mass or more and 0.01% by mass or less, more preferably 0.0000005% by mass or more and 0.005% by mass or less, and more preferably 0.0000001% by mass or more and 0.001% by mass or less, relative to the total mass of the first polishing composition. It is more preferably not more than 0.000004% by mass, and particularly preferably 0.000004% by mass or more and 0.0005% by mass or less.

<Amine compound A>
The polishing composition according to the second aspect of the present invention includes an amine compound A having two or more nitrogen atoms and a pKa higher than that of ammonia, and the content C2 of the amine compound A represented by the following formula (2) is in the range of more than 0% and 5.5% or less. By adding the amine compound A in such a range to the polishing composition, the etching of the object to be polished can be efficiently advanced and the polishing rate can be improved.

In the above formula (2), A2 is the content of ammonia (unit: % by mass) in the second polishing composition, and B2 is the content of amine compound A in the second polishing composition (unit: % by mass).

When the content C2 of the amine compound A is 0% in the second polishing composition, the polishing rate is lowered. On the other hand, when the content C2 of the amine compound A in the second polishing composition exceeds 5.5%, the etching rate is suppressed, resulting in a decrease in polishing rate. In the second polishing composition, the content C2 of the amine compound A is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1.0% or more. In the second polishing composition, the content C2 of the amine compound A is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly preferably 3.0% or less.

That is, in the second polishing composition, the content C2 of the amine compound A is preferably 0.1% or more and 5.0% or less, more preferably 0.5% or more and 4.5% or less, further preferably 1.0% or more and 4.0% or less, and particularly preferably 1.0% or more and 3.0% or less.

The pKa of amine compound A is preferably 9.5 or more, more preferably 9.7 or more, and even more preferably 9.8 or more, from the viewpoint that the effects of the present invention are more exhibited. From the same point of view, the pKa of amine compound A is preferably 14.0 or less, more preferably 13.0 or less, and even more preferably 12.0 or less. That is, the pKa of amine compound A is preferably 9.5 or more and 14.0 or less, more preferably 9.7 or more and 13.0 or less, and even more preferably 9.8 or more and 12.0 or less.

As the amine compound A, aliphatic amines, alicyclic amines, aromatic amines, heterocyclic amines, guanidines, piguanides, and the like can be used without particular limitation as long as they have two or more nitrogen atoms and have a pKa higher than that of ammonia. Moreover, the amino group of the amine compound A is not particularly limited and may be a primary amino group, a secondary amino group, a tertiary amino group, or the like, and may have a combination thereof. Furthermore, the amine compound A may have a substituent such as a hydroxy group. The number of nitrogen atoms in the amine compound A is not particularly limited as long as it is 2 or more, and may be 3 or more, 4 or more, 5 or more, or 10 or more. The number of nitrogen atoms in the amine compound A may be 20 or less, 15 or less, 8 or less, 6 or less, 4 or less, or 3 or less. Among amine compounds A, compounds having a piperazine skeleton (piperazine ring) are classified as piperazine compounds contained in the first polishing composition.

The aliphatic amine may be an amine having a branched structure or an amine having no branched structure (linear amine). Aliphatic amines may be saturated, containing no double or triple bonds, or unsaturated. The number of carbon atoms in the aliphatic amine is not particularly limited as long as it is 1 or more, but may be 2 or more, 3 or more, 5 or more, 10 or more, or 15 or more. The number of carbon atoms in the aliphatic amine may be 30 or less, 20 or less, 15 or less, 10 or less, or 5 or less.

Alicyclic amines include amines containing one or more carbocyclic rings. The above carbocyclic ring may be a saturated ring containing no double bond or triple bond in the ring, a partially saturated ring or an unsaturated ring. The number of atoms constituting the carbocyclic ring may be 3 or more, 4 or more, 5 or more, or 6 or more. The number of atoms constituting the carbocyclic ring may be 15 or less, 10 or less, 8 or less, 7 or less, or 6 or less.

Aromatic amines include amines having one or more aromatic rings (excluding heterocycles). A benzene ring, a naphthalene ring, etc. are mentioned as an aromatic ring. As used herein, aromatic amines shall not include heterocyclic amines.

Heterocyclic amines include amines containing one or more heterocycles. Heterocycles contain heteroatoms independently selected from nitrogen, oxygen and sulfur atoms within the ring. The number of heteroatoms contained in the heterocyclic ring is not particularly limited as long as it is 1 or more, but may be 2 or more or 3 or more. The number of heteroatoms contained in the heterocyclic ring may be 5 or less, 4 or less, or 3 or less. A heterocyclic ring may be a saturated ring containing no double or triple bond in the ring, a partially saturated ring or an unsaturated ring. A heterocycle may be an aromatic ring or a non-aromatic ring. The number of atoms constituting the heterocyclic ring may be 3 or more, 4 or more, 5 or more, or 6 or more. The number of atoms constituting the heterocyclic ring may be 15 or less, 10 or less, 8 or less, 7 or less, or 6 or less.

Specific examples of the amine compound A include ethylenediamine, propylenediamine (1,2-diaminopropane), trimethylenediamine (1,3-diaminopropane), tetramethylenediamine (1,4-diaminobutane), pentamethylenediamine (1,5-diaminopentane), hexamethylenediamine (1,6-diaminohexane), heptamethylenediamine (1,7-diaminoheptane), octamethylenediamine (1,8-diaminooc tan), nonamethylenediamine (1,9-diaminononane), decamethylenediamine (1,10-diaminodecane), N-methyl-1,3-propanediamine, 3-dimethylamino-1-propylamine, 3-diethylamino-1-propylamine, 3-dibutylamino-1-propylamine, N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl-1,3-propanediamine ( TMPDA) and other aliphatic amines; cyclobutanediamine, isophoronediamine, bicyclo[2,2,1]heptanebismethylamine, tricyclo[3,3,1,1^3,7] Decane-1,3-diamine, trans-1,2-cyclohexyldiamine, cis-1,2-cyclohexyldiamine, trans-1,3-cyclohexyldiamine, cis-1,3-cyclohexyldiamine, trans-1,4-cyclohexyldiamine (pKa: 10.73), cis-1,4-cyclohexyldiamine, 4,4'-diaminodicyclohexyl Methane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, 3,3',5,5'-tetraethyl-4,4'-diaminodicyclohexylmethane, 3,5-diethyl-3',5'-dimethyl-4,4'-diaminodicyclohexylmethane Hexylmethane, 4,4'-diaminodicyclohexyl ether, 3,3'-dimethyl-4,4'-diaminodicyclohexyl ether, 3,3'-diethyl-4,4'-diaminodicyclohexyl ether, 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexyl ether, 3,3',5,5'-tetraethyl-4,4'-diaminodicyclohexyl ether, 3,5-diethyl- 3',5'-dimethyl-4,4'-diaminodicyclohexyl ether, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(3-methyl-4-aminocyclohexyl)propane, 2,2-bis(3-ethyl-4-aminocyclohexyl)propane, 2,2-bis(3,5-dimethyl-4-aminocyclohexyl)propane, 2,2-bis(3,5-diethyl-4-aminocyclohexyl) i) alicyclic amines such as propane and 2,2-(3,5-diethyl-3',5'-dimethyl-4,4'-diaminodicyclohexyl)propane; guanidines such as guanidine, 2-aminoguanidine and diphenylguanidine; biguanides such as butylbiguanide, 1-phenylpiguanide and 1-o-tolylbiguanide; Heterocyclic amines such as cyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), N-(3-aminopropyl)morpholine, 4-dimethylaminopyridine (DMAP); and the like, but are not limited thereto.

Amine compound A can be used alone or in combination of two or more.

Among these amine compounds A, at least one selected from the group consisting of trans-1,2-cyclohexyldiamine (pKa: 10.00) and ethylenediamine (pKa: 10.03) is preferable.

The content B2 of the amine compound A in the second polishing composition is not particularly limited as long as the content C2 of the amine compound A represented by the above formula (2) is more than 0% and 5.5% or less.

However, when the second polishing composition according to the present invention is in the form of a concentrated liquid, the content B2 of the amine compound A in the concentrated liquid is preferably 0.000001% by mass or more, more preferably 0.00001% by mass or more, more preferably 0.00005% by mass or more, further preferably 0.0001% by mass or more, and further preferably 0.0000% by mass. 5% by mass or more is particularly preferred. Further, when the second polishing composition according to the present invention is in the form of a concentrated liquid, the content B2 of the amine compound A is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and particularly preferably 0.008% by mass or less, relative to the total mass of the concentrated liquid of the second polishing composition.

Further, when the second polishing composition according to the present invention is in the form of a diluted solution, the content B2 of the amine compound A in the second polishing composition is preferably 0.000001% by mass or more, more preferably 0.000005% by mass or more, further preferably 0.00001% by mass or more, and particularly preferably 0.00004% by mass, relative to the total mass of the second polishing composition. When the second polishing composition according to the present invention is in the form of a diluted solution, the content B2 of the amine compound A is, for example, 0.1% by mass or less, may be 0.05% by mass or less, preferably 0.01% by mass or less, more preferably 0.005% by mass or less, further preferably 0.001% by mass or less, and particularly preferably 0.0005% by mass or less, relative to the total mass of the second polishing composition.

That is, when the second polishing composition according to the present invention is in the form of a diluted solution, the content B2 of the amine compound A in the second polishing composition is preferably 0.000001% by mass or more and 0.01% by mass or less, more preferably 0.000005% by mass or more and 0.005% by mass or less, and 0.00001% by mass or more and 0.001% by mass or less, relative to the total mass of the second polishing composition. More preferably, it is particularly preferably 0.00004% by mass or more and 0.0005% by mass or less.

<Amine compound B>
The polishing composition according to the second aspect of the present invention contains an amine compound B which is a secondary amine or a tertiary amine having one nitrogen atom and a pKa higher than that of ammonia, and the content C3 represented by the following formula (3) of the amine compound B is in the range of more than 0% and 35% or less. By adding the amine compound B in such a range to the polishing composition, the etching of the object to be polished can be efficiently advanced and the polishing rate can be improved.

In the above formula (3), A3 is the content of ammonia (unit: % by mass) in the third polishing composition, and B3 is the content of amine compound B in the third polishing composition (unit: % by mass).

In the third polishing composition, when the content C3 of the amine compound B is 0%, the polishing rate is lowered. On the other hand, in the third polishing composition, when the content C3 of the amine compound B exceeds 35%, the etching rate is suppressed, resulting in a decrease in polishing rate. In the third polishing composition, the content C3 of the amine compound B is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1.0% or more. In the third polishing composition, the content C3 of the amine compound B is preferably 30.0% or less, more preferably 20.0% or less, even more preferably 15.0% or less, and particularly preferably 10.0% or less.

That is, in the third polishing composition, the content C3 of the amine compound B is preferably 0.1% or more and 30.0% or less, more preferably 0.5% or more and 20.0% or less, further preferably 1.0% or more and 15.0% or less, and particularly preferably 1.0% or more and 10.0% or less.

The pKa of amine compound B is preferably 9.5 or more, more preferably 9.8 or more, and even more preferably 10.0 or more, from the viewpoint that the effects of the present invention are more exhibited. From the same point of view, the pKa of amine compound A is preferably 15.0 or less, more preferably 13.0 or less, and even more preferably 12.0 or less. That is, the pKa of amine compound B is preferably from 9.5 to 15.0, more preferably from 9.8 to 13.0, and even more preferably from 10.0 to 12.0.

As the amine compound B, aliphatic amines, alicyclic amines, aromatic amines, heterocyclic amines, and the like can be used without particular limitation as long as they have one nitrogen atom and have a higher pKa than ammonia. Moreover, the amino group of the amine compound B is a secondary amino group or a tertiary amino group, but may have a combination thereof. Furthermore, the amine compound B may have a substituent such as a hydroxy group.

The aliphatic amine may be an amine having a branched structure or an amine having no branched structure (linear amine). Aliphatic amines may be saturated, containing no double or triple bonds, or unsaturated. The number of carbon atoms in the aliphatic amine is not particularly limited as long as it is 1 or more, but it may be 2 or more, 3 or more, 5 or more, or 10 or more. The number of carbon atoms in the aliphatic amine may be 20 or less, 15 or less, 10 or less, or 5 or less.

Aromatic amines include amines having one or more aromatic rings (excluding heterocycles). A benzene ring, a naphthalene ring, etc. are mentioned as an aromatic ring.

Heterocyclic amines include amines containing one or more heterocycles. Heterocycles contain heteroatoms independently selected from nitrogen, oxygen and sulfur atoms within the ring. A heterocyclic ring may be a saturated ring containing no double or triple bond in the ring, a partially saturated ring or an unsaturated ring. A heterocycle may be an aromatic ring or a non-aromatic ring. The number of atoms constituting the heterocyclic ring may be 3 or more, 4 or more, 5 or more, or 6 or more. The number of atoms constituting the heterocyclic ring may be 15 or less, 10 or less, 8 or less, 7 or less, or 6 or less.

Specific examples of amine compound B include dimethylamine, diethylamine (pKa: 10.90), di(n-propyl)amine, diisopropylamine, di(n-butyl)amine, diisobutylamine, di(sec-butyl)amine, dimethylethylamine, methyldiethylamine, dimethylpropylamine, dimethylbutylamine, dimethylisobutylamine, dimethylisopropylamine, dimethylsec-butylamine, dimethyltert-butylamine, triethylamine, tripropylamine, tributylamine, N-methylethanolamine. , N-methyldiethanolamine, N-ethylethanolamine, N-butylbutanolamine, N,N-dibutylethanolamine; alicyclic amines such as octylamine, dicyclopentylamine, and dicyclohexylamine; aromatic amines such as benzylmethylamine, benzylethylamine, and diethylbenzylamine; It is not limited to these.

The amine compound B can be used singly or in combination of two or more.

Among these amine compounds B, at least one selected from piperidine (pKa: 10.97), N-methylpiperidine (pKa: 10.08), triethylamine (pKa: 10.68), and N-methylpyrrolidine (pKa: 10.31) is preferred.

The content B3 of the amine compound B in the third polishing composition is not particularly limited as long as the content C3 of the amine compound B represented by the above formula (3) is more than 0% and 35% or less.

However, when the third polishing composition according to the present invention is in the form of a concentrated liquid, the content B3 of the amine compound in the concentrated liquid is preferably 0.000001% by mass or more, more preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, further preferably 0.001% by mass or more, and even more preferably 0.004% by mass or more, relative to the total mass of the concentrated liquid of the second polishing composition. is particularly preferred. Further, when the second polishing composition according to the present invention is in the form of a concentrated liquid, the content B3 of the amine compound B is preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.1% by mass or less, and particularly preferably 0.07% by mass or less, relative to the total mass of the concentrated liquid of the third polishing composition.

Further, when the third polishing composition according to the present invention is in the form of a diluted solution, the content B3 of the amine compound B in the polishing composition is preferably 0.000001% by mass or more, more preferably 0.000005% by mass or more, more preferably 0.00001% by mass or more, further preferably 0.00005% by mass or more, and further preferably 0.0001% by mass or more. % or more is particularly preferred. Further, when the third polishing composition according to the present invention is in the form of a diluted solution, the content B3 of the amine compound B is, for example, 0.1% by mass or less, may be 0.05% by mass or less, preferably 0.01% by mass or less, more preferably 0.008% by mass or less, and further preferably 0.005% by mass or less, relative to the total mass of the third polishing composition.

That is, when the third polishing composition according to the present invention is in the form of a diluted solution, the content B3 of the amine compound B in the polishing composition is preferably 0.000001% by mass or more and 0.1% by mass or less, more preferably 0.000005% by mass or more and 0.1% by mass or less, more preferably 0.00001% by mass or more and 0.05% by mass or less, and 0.0 It is more preferably 0005% by mass or more and 0.01% by mass or less, and particularly preferably 0.0001% by mass or more and 0.008% by mass or less.

<Other basic compounds>
The polishing composition according to some embodiments of the present invention may further contain other basic compounds as long as the contents C1 to C3 of the piperazine compound represented by the formulas (1) to (3), the amine compound A, and the amine compound B satisfy the above ranges. Examples of such other basic compounds include, for example, hydroxides or salts of Group 2 elements or alkali metals such as calcium hydroxide, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium sulfate, potassium acetate, potassium chloride, sodium hydroxide, sodium hydrogen carbonate, and sodium carbonate; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide; , ammonium carbonate, ammonium hydrogen carbonate; and the like. again. Amine compounds with a lower pKa than ammonia can also be used as other basic compounds. These other basic compounds can be used singly or in combination of two or more. In the present specification, the piperazine compound, amine compound A, and amine compound B do not include the above other basic compounds.

However, when the polishing composition according to some embodiments of the present invention is in a concentrated liquid state, the content of the other basic compound is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less, relative to the total mass of the basic compounds.

When the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of the other basic compound is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less, relative to the total mass of the basic compounds. Regardless of whether the liquid is a concentrated liquid or a diluent, the most preferable form is one in which the content of other basic compounds is 0% by mass, i.e., a form containing no basic compounds other than ammonia, piperazine compound, amine compound A, and amine compound B.

When the polishing composition according to some embodiments of the present invention is in the form of a concentrated liquid, the content of the basic compound in the concentrated liquid is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, further preferably 0.01% by mass or more, and particularly preferably 0.03% by mass or more. A high polishing rate can be easily obtained by increasing the content of the basic compound. In this case, the content of the basic compound in the concentrated liquid of the polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less, from the viewpoint of storage stability, filterability, and the like.

That is, when the polishing composition according to some embodiments of the present invention is in a concentrated liquid state, the content of the basic compound in the concentrated liquid is preferably 0.001% by mass or more and 10% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less, further preferably 0.01% by mass or more and 3% by mass or less, and particularly preferably 0.03% by mass or more and 1% by mass or less.

When the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of the basic compound in the polishing composition is not particularly limited, but is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.002% by mass or more. Further, when the polishing composition according to some embodiments of the present invention is in the form of a diluted solution, the content of the basic compound in the polishing composition is preferably 5% by mass or less, more preferably 2% by mass or less, further preferably 1% by mass or less, and particularly preferably 0.5% by mass or less, from the viewpoint of storage stability, filterability, and the like.

[Dispersion medium]
In some embodiments of the present invention, the polishing composition preferably contains a dispersion medium (especially water). The dispersion medium (especially water) has the function of dissolving or dispersing the components contained in the polishing composition.

From the viewpoint of preventing contamination of the object to be polished and inhibiting the action of other components, it is preferable that the water contain as few impurities as possible. As such water, for example, water having a total content of transition metal ions of 100 ppb or less is preferable. Here, the purity of water can be increased by, for example, removal of impurity ions using an ion exchange resin, removal of foreign matter using a filter, distillation, or other operations. Specifically, as water, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, or the like.

The dispersion medium may be a mixed solvent of water and an organic solvent for dispersing or dissolving each component. In this case, the organic solvent used includes acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, propylene glycol, etc., which are organic solvents miscible with water. Alternatively, these organic solvents may be used without being mixed with water, and each component may be dispersed or dissolved and then mixed with water. These organic solvents can be used singly or in combination of two or more. Here, the dispersion medium is preferably water only.

[Water-soluble polymer]
In some embodiments of the invention, the polishing composition may contain a water-soluble polymer. The water-soluble polymer adheres to the surface of the object to be polished and protects the surface of the object to be polished from uneven or excessive etching that may occur due to the action of the basic compound. This can improve the quality of the surface of the object to be polished after polishing.

As used herein, the term "polymer" refers to a (co)polymer having a weight average molecular weight of 5,000 or more. The weight average molecular weight can be measured by gel permeation chromatography (GPC), and specifically, the value measured by the method described in Examples is adopted. In addition, only when the molecular weight cannot be measured by GPC, the molecular weight calculated from the molecular formula is adopted as the weight average molecular weight.

In some embodiments of the present invention, as the water-soluble polymer, those having at least one functional group selected from cationic groups, anionic groups and nonionic groups in the molecule can be used.

In some embodiments of the present invention, water-soluble polymers include those containing hydroxyl groups, carboxyl groups, acyloxy groups, sulfo groups, amide structures, imide structures, quaternary ammonium structures, heterocyclic structures, vinyl structures, etc. in the molecule.

In some embodiments of the present invention, water-soluble polymers include polymers having structural units derived from vinyl alcohol (hereinafter also referred to as "polyvinyl alcohol-based polymers"), cellulose derivatives, starch derivatives, polymers having oxyalkylene units, and water-soluble polymers having nitrogen atoms. Among others, it is preferable to contain at least one of a polyvinyl alcohol-based polymer and a cellulose derivative. A polishing composition containing these polymers tends to reduce the haze of an object to be polished.

(Polyvinyl alcohol polymer)
The polyvinyl alcohol-based polymer may contain only vinyl alcohol units (hereinafter also referred to as "VA units") as repeating units, or may contain repeating units other than VA units (hereinafter also referred to as "non-VA units") in addition to VA units. A vinyl alcohol unit is a structural moiety represented by the following chemical formula: --CH ₂ --CH(OH)--. The polyvinyl alcohol-based polymer may be a random copolymer containing VA units and non-VA units, or may be a block copolymer or a graft copolymer. The polyvinyl alcohol-based polymer may contain only one type of non-VA unit, or may contain two or more types of non-VA units.

The polyvinyl alcohol-based polymer used in the polishing composition disclosed herein may be unmodified polyvinyl alcohol (non-modified PVA) or modified polyvinyl alcohol (modified PVA). Here, the unmodified PVA is produced by hydrolyzing (saponifying) polyvinyl acetate, and refers to a polyvinyl alcohol-based polymer that is substantially free of repeating units other than repeating units (—CH ₂ —CH(OCOCH ₃ )—) having a vinyl-polymerized structure of vinyl acetate and repeating units other than VA units. The degree of saponification of the non-modified PVA may be, for example, 60% or more, may be 70% or more from the viewpoint of water solubility, may be 80% or more, or may be 90% or more. In some embodiments, unmodified PVA with a degree of saponification of 95% or higher or 98% or higher can be preferably employed as the water-soluble polymer compound.

The polyvinyl alcohol-based polymer may be a modified PVA containing VA units and non-VA units having at least one structure selected from oxyalkylene groups, carbonyl groups, acetoacetyl groups, carboxy groups, (di)carboxylic acid groups, (di)carboxylic acid esters, phenyl groups, naphthyl groups, sulfo groups, amino groups, hydroxyl groups, amide groups, imide groups, nitrile groups, ether groups, ester groups, and salts thereof.

Examples of non-VA units that can be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl type monomers and N-(meth)acryloyl type monomers, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, and repeating units derived from (di)acetone compounds. A preferred example of the N-vinyl type monomer is N-vinylpyrrolidone. A preferred example of the N-(meth)acryloyl type monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be a vinyl ester of a monocarboxylic acid having 3 or more and 7 or less carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, and vinyl hexanoate. Preferred examples of the (di)acetone compound include diacetone (meth)acrylamide and acetylacetone.

The polyvinyl alcohol-based polymer may be modified PVA in which some of the VA units contained in the polyvinyl alcohol-based polymer are acetalized with an aldehyde compound or a ketone compound. In a preferred embodiment of the technology disclosed herein, the acetalized modified PVA is a water-soluble polymer obtained by an acetalization reaction between the above unmodified PVA and an aldehyde compound.

In some embodiments of the present invention, the aldehyde compound used to produce the acetalized modified PVA is not particularly limited. In a preferred embodiment, the aldehyde compound has 1 to 7 carbon atoms, more preferably 2 to 7 carbon atoms.

Examples of the aldehyde compound include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, tert-butyraldehyde, hexylaldehyde and n-pentylaldehyde; alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde; These may be used individually by 1 type, and may be used in combination of 2 or more type. In addition, excluding formaldehyde, one or more hydrogen atoms may be substituted with halogen or the like. Among them, straight-chain or branched alkylaldehydes are preferred because of their high solubility in water and easy acetalization reaction, and among them, acetaldehyde, n-propylaldehyde, n-butyraldehyde, and n-pentylaldehyde are more preferred.

As the aldehyde compound, in addition to the above, aldehyde compounds having 8 or more carbon atoms such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde may be used. As the polyvinyl alcohol-based polymer, cation-modified polyvinyl alcohol into which a cationic group such as a quaternary ammonium structure is introduced may be used. Examples of the cation-modified polyvinyl alcohol include those into which a cationic group derived from a monomer having a cationic group, such as diallyldialkylammonium salts and N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salts, is introduced. The polyvinyl alcohol-based polymer may also have a structural portion in which the non-VA unit is represented by the chemical formula: --CH ₂ --CH(CR ⁵ (OR ⁸ )--CR ⁶ (OR ⁹ )--R ⁷ )--. Here, R ⁵ to R ⁷ each independently represent a hydrogen atom or an organic group, and R ⁸ and R ⁹ each independently represent a hydrogen atom or R ¹⁰ --CO-- (wherein R ¹⁰ represents an alkyl group). Examples of such modified PVA include modified PVA having a 1,2-diol structure in the side chain.

The ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. Although not particularly limited, in some embodiments, the molar ratio of the VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting the polyvinyl alcohol polymer may be VA units. Here, "substantially 100%" means that the polyvinyl alcohol-based polymer does not contain non-VA units at least intentionally, and typically the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (for example, less than 1%), and includes cases where it is 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the polyvinyl alcohol polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

The content of VA units (mass-based content) in the polyvinyl alcohol-based polymer may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more. Although not particularly limited, in some embodiments, the content of the VA unit may be 50% by mass or more (e.g., more than 50% by mass), 70% by mass or more, or 80% by mass or more (e.g., 90% by mass or more, or 95% by mass or more, or 98% by mass or more). Substantially 100% by mass of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100% by mass" means that non-VA units are not at least intentionally included as repeating units constituting the polyvinyl alcohol-based polymer, and typically the content of non-VA units in the polyvinyl alcohol-based polymer is less than 2% by mass (for example, less than 1% by mass). In some other aspects, the content of VA units in the polyvinyl alcohol polymer may be, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 70% by mass or less.

The polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit contents in the same molecule. Here, the polymer chain refers to a portion (segment) that constitutes a part of one molecule of polymer. For example, the polyvinyl alcohol-based polymer may contain a polymer chain A having a VA unit content of more than 50% by mass and a polymer chain B having a VA unit content of less than 50% by mass (i.e., having a non-VA unit content of more than 50% by mass) in the same molecule.

The polymer chain A may contain only VA units as repeating units, or may contain non-VA units in addition to VA units. The content of VA units in the polymer chain A may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the content of VA units in polymer chain A may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting the polymer chain A may be VA units.

The polymer chain B may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain B may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the content of non-VA units in polymer chain B may be 95 wt% or more, or 98 wt% or more. Substantially 100% by mass of the repeating units constituting the polymer chain B may be non-VA units.

Examples of polyvinyl alcohol-based polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The graft copolymer may be a graft copolymer having a structure in which a polymer chain B (side chain) is grafted to a polymer chain A (main chain), or a graft copolymer having a structure in which a polymer chain A (side chain) is grafted to a polymer chain B (main chain). In one embodiment, a polyvinyl alcohol-based polymer having a structure in which a polymer chain B is grafted onto a polymer chain A can be used.

Examples of the polymer chain B include a polymer chain whose main repeating unit is a repeating unit derived from an N-vinyl type monomer, a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer, and a polymer chain whose main repeating unit is an oxyalkylene unit. In the present specification, the term "main repeating unit" refers to a repeating unit containing more than 50% by mass unless otherwise specified.

A suitable example of the polymer chain B is a polymer chain having an N-vinyl type monomer as the main repeating unit, that is, an N-vinyl polymer chain. The content of repeating units derived from the N-vinyl type monomer in the N-vinyl polymer chain is typically more than 50% by mass, may be 70% by mass or more, may be 85% by mass or more, and may be 95% by mass or more. Substantially all of the polymer chain B may be repeating units derived from an N-vinyl type monomer.

Examples of N-vinyl type monomers include monomers having a nitrogen-containing heterocyclic ring (eg, lactam ring) and N-vinyl chain amides. Specific examples of N-vinyllactam type monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione and the like. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, N-vinylbutyric acid amide and the like. Polymer chain B can be, for example, an N-vinyl polymer chain in which more than 50% by weight (eg, 70% by weight or more, or 85% by weight or more, or 95% by weight or more) of its repeating units are N-vinylpyrrolidone units. Substantially all of the repeating units constituting the polymer chain B may be N-vinylpyrrolidone units.

Another example of the polymer chain B is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer, that is, an N-(meth)acryloyl polymer chain. The content of repeating units derived from the N-(meth)acryloyl-type monomer in the N-(meth)acryloyl-based polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, and may be 95% by mass or more. Substantially all of the polymer chain B may be repeating units derived from N-(meth)acryloyl type monomers.

Examples of N-(meth)acryloyl-type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and Nn-butyl(meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N, N-diisopropyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide such as N,N-di(n-butyl)(meth)acrylamide; N-hydroxyalkyl(meth)acrylamide such as N-hydroxyethyl(meth)acrylamide; and the like. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine and the like.

Another example of polymer chain B is a polymer chain containing an oxyalkylene unit as a main repeating unit, that is, an oxyalkylene-based polymer chain. The content of oxyalkylene units in the oxyalkylene-based polymer chain is typically more than 50% by mass, may be 70% by mass or more, may be 85% by mass or more, or may be 95% by mass or more. Substantially all of the repeating units contained in polymer chain B may be oxyalkylene units.

Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each such oxyalkylene unit may be a repeating unit derived from the corresponding alkylene oxide. The oxyalkylene unit contained in the oxyalkylene-based polymer chain may be of only one type, or may be of two or more types. For example, it may be an oxyalkylene polymer chain containing a combination of oxyethylene units and oxypropylene units. In the oxyalkylene-based polymer chain containing two or more oxyalkylene units, the oxyalkylene units may be random copolymers, block copolymers, or graft copolymers of the corresponding alkylene oxides.

Further examples of the polymer chain B include a polymer chain containing a repeating unit derived from an alkyl vinyl ether (e.g., a vinyl ether having an alkyl group having 1 to 10 carbon atoms), a polymer chain containing a repeating unit derived from a monocarboxylic acid vinyl ester (e.g., a vinyl ester of a monocarboxylic acid having 3 or more carbon atoms), a polymer chain in which a portion of the VA units are acetalized with an aldehyde (e.g., an alkyl aldehyde having an alkyl group having 1 to 7 carbon atoms), and a cationic group (e.g., a cation having a quaternary ammonium structure). a polymer chain into which a functional group) has been introduced, and the like.

In some embodiments of the present invention, the polyvinyl alcohol-based polymer in the polishing composition may be unmodified PVA, modified PVA, or a combination of unmodified PVA and modified PVA. In the embodiment in which the unmodified PVA and the modified PVA are used in combination, the amount of the modified PVA used relative to the total amount of the polyvinyl alcohol polymer contained in the polishing composition may be, for example, less than 95% by mass, 90% by mass or less, 75% by mass or less, 50% by mass or less, 30% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less. The polishing composition according to the present invention can be preferably implemented, for example, in a mode using modified PVA as the polyvinyl alcohol-based polymer.

(cellulose derivative)
In some embodiments of the present invention, the term "cellulose derivative" refers to cellulose in which some of the hydroxy groups have been substituted with other different substituents. A cellulose derivative may be used individually by 1 type, and may be used in combination of 2 or more type. Examples of cellulose derivatives include cellulose derivatives such as hydroxyethylcellulose (HEC), hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose and carboxymethylcellulose, and pullulan.

(starch derivative)
According to some embodiments of the invention the water soluble polymer comprises a starch derivative. Starch derivatives are polymers containing α-glucose units as main repeating units, such as pregelatinized starch, pullulan, carboxymethyl starch, cyclodextrin, and the like. A starch derivative may be used individually by 1 type, and may be used in combination of 2 or more type.

(Polymer having an oxyalkylene unit)
According to some embodiments of the invention, the water-soluble polymer comprises a polymer having oxyalkylene units. Polymers containing oxyalkylene units include polyethylene oxide (PEO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO. Block copolymers of ethylene oxide (EO) and propylene oxide (PO) include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.). PEO-PPO-PEO type triblock copolymers are usually more preferred. A polymer having an oxyalkylene unit may be used alone or in combination of two or more.

(Water-soluble polymer having nitrogen atoms)
According to some embodiments of the present invention, the water-soluble polymer contains nitrogen atoms with a view to reducing haze. By including the water-soluble polymer having nitrogen atoms, the haze of the object to be polished can be reduced.

In some embodiments of the present invention, the nitrogen atom-containing water-soluble polymer may be used singly or in combination of two or more. Examples of water-soluble polymers having nitrogen atoms include poly N-acryloylmorpholine (PACMO), poly N-vinylpyrrolidone (PVP), polyhydroxylethylacrylamide (PHEAA), poly N-vinylimidazole (PVI), poly N-vinylcarbazole, poly N-vinylcaprolactam, poly N-vinylpiperidine and the like. Among them, it is preferable to contain poly-N-acryloylmorpholine (PACMO) from the viewpoint of reducing the haze of the object to be polished.

According to some embodiments of the present invention, the weight average molecular weight of the water-soluble polymer is preferably 5,000 or greater, more preferably 6,000 or greater, and even more preferably 1×10 ⁴ or greater. According to this embodiment, there is a technical effect of improving the haze reduction effect. According to some embodiments of the present invention, the weight-average molecular weight of the water-soluble polymer is preferably 200×10 ⁴ or less, more preferably 100×10 ⁴ or less, and even more preferably 50×10 ⁴ or less, from the viewpoint of haze reduction, washability, and the like. In the above, when the polishing composition contains two or more water-soluble polymers, the weight-average molecular weight of the water-soluble polymer is 5,000 or more for the smallest water-soluble polymer among them. By being such an embodiment, the desired effects of the present invention can be obtained efficiently.

According to some embodiments of the invention, the water-soluble polymer is a polyvinyl alcohol-based polymer. The weight average molecular weight of the polyvinyl alcohol polymer is preferably 5,000 or more, more preferably 6,000 or more, and even more preferably 1.0×10 ⁴ or more. According to this embodiment, there is a technical effect of improving the haze reduction effect. According to some embodiments of the present invention, the weight average molecular weight of the polyvinyl alcohol polymer is preferably 100×10 ⁴ or less, more preferably 30×10 ⁴ or less, and even more preferably 10×10 ⁴ or less. According to such an embodiment, dispersion stability is improved.

According to some embodiments of the invention, the water-soluble polymer is a cellulose derivative. The weight average molecular weight of the cellulose derivative is preferably 5,000 or more, more preferably 1×10 ⁴ or more, and even more preferably 10×10 ⁴ or more. According to this embodiment, there is a technical effect of improving the haze reduction effect. According to some embodiments of the present invention, the weight average molecular weight of the cellulose derivative is preferably 200×10 ⁴ or less, more preferably 150×10 ⁴ or less, even more preferably 100×10 ⁴ or less. According to such an embodiment, dispersion stability is improved.

According to some embodiments of the invention, the water-soluble polymer is a water-soluble polymer having nitrogen atoms. The weight average molecular weight of the nitrogen atom-containing water-soluble polymer is preferably 5,000 or more, more preferably 7,500 or more, and even more preferably 1×10 ⁴ or more. According to this embodiment, there is a technical effect of improving the haze reduction effect. According to some embodiments of the present invention, the weight average molecular weight of the nitrogen atom-containing water-soluble polymer is preferably 100×10 ⁴ or less, more preferably 75×10 ⁴ or less, and even more preferably 50×10 ⁴ or less. According to such an embodiment, dispersion stability is improved.

In some embodiments of the present invention, when the polishing composition is in the form of a concentrated liquid, the content of the water-soluble polymer in the concentrated liquid is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, further preferably 0.001% by mass or more, and particularly preferably 0.01% by mass or more, from the viewpoint of improving stability. In some embodiments of the present invention, when the polishing composition is in the form of a concentrate, the content of the water-soluble polymer in the concentrate is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of storage stability, filterability, and the like.

In some embodiments of the present invention, when the polishing composition is in the form of a diluted solution, the content of the water-soluble polymer is preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, and particularly preferably 0.001% by mass or more, from the viewpoint of improving the haze reduction effect. In some embodiments of the present invention, when the polishing composition is in the form of a diluted solution, the content of the water-soluble polymer is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less, from the viewpoint of maintaining the polishing rate. In addition, when using 2 or more types of water-soluble polymers, the said content points out the total amount. In some preferred embodiments of the present invention, the water-soluble polymer contains hydroxy groups with a view to reducing haze.

In some embodiments of the present invention, the polishing composition can contain any two or more water-soluble polymers. As the water-soluble polymer, for example, two or more water-soluble polymers selected from the group consisting of polyvinyl alcohol-based polymers, cellulose derivatives, starch derivatives, and nitrogen atom-containing water-soluble polymers can be used in combination. Among others, it is preferable to contain two or more water-soluble polymers selected from the group consisting of polyvinyl alcohol-based polymers, cellulose derivatives, and water-soluble polymers having nitrogen atoms. A polishing composition containing these water-soluble polymers tends to reduce the haze of an object to be polished.

When the polishing composition contains two or more types of water-soluble polymers, for example, one or more of each of a polyvinyl alcohol-based polymer and a water-soluble polymer having a nitrogen atom, one or more of each of a cellulose derivative and a polyvinyl alcohol-based polymer, and one or more of each of a cellulose derivative and a water-soluble polymer having a nitrogen atom can be used in combination.

When the polishing composition contains at least one water-soluble polymer selected from polyvinyl alcohol-based polymer and nitrogen atom-containing water-soluble polymer, the polyvinyl alcohol-based polymer and the nitrogen atom-containing water-soluble polymer may be the water-soluble polymers described above as some embodiments of the present invention. Among them, it is preferable to use a water-soluble polymer in combination such as one or more types of acetalized modified PVA and poly N-acryloylmorpholine, one or more types of unmodified PVA and poly N-acryloylmorpholine, one or more types of unmodified PVA and poly N-vinylpyrrolidone, and one or more types of unmodified PVA and polyhydroxylethylacrylamide.

In some embodiments of the present invention, when two or more water-soluble polymers are used, the content ratio of the two or more water-soluble polymers is not particularly limited. For example, in a polishing composition (concentrate or diluent) containing a polyvinyl alcohol-based polymer and a water-soluble polymer having a nitrogen atom, the ratio of the content of the polyvinyl alcohol-based polymer to the content of the water-soluble polymer having a nitrogen atom (polyvinyl alcohol-based polymer/water-soluble polymer having a nitrogen atom) is preferably 0.01 or more, may be 0.05 or more, or may be 0.15 or more (e.g., 0.5 or more). Although the upper limit of the content ratio is not particularly limited, it is preferably 99 or less, may be 19 or less, or may be 6 or less (for example, 2 or less). The content of the polyvinyl alcohol-based polymer and the water-soluble polymer having nitrogen atoms is preferably 1:99 to 99:1 in mass ratio, may be 5:95 to 95:5, or may be 15:85 to 85:15 (eg 65:35 to 35:65).

<Surfactant>
Polishing compositions according to some embodiments of the present invention may optionally contain a surfactant. By including a surfactant in the polishing composition, haze on the surface of the object to be polished after polishing can be reduced more effectively. Any of anionic, cationic, nonionic and amphoteric surfactants can be used as surfactants. Generally, anionic or nonionic surfactants can be preferably employed. Nonionic surfactants are more preferable from the viewpoint of low foaming properties and ease of pH control. For example, oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyalkylene derivatives (e.g., polyoxyalkylene adducts) such as polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; ; and other nonionic surfactants. The surfactant preferably contains a surfactant containing a polyoxyalkylene structure. Surfactants can be used singly or in combination of two or more.

Specific examples of nonionic surfactants containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyoxyethylene propyl ether, polyoxyethylene butyl ether, poly Oxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether Ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, monooleic acid Polyoxyethylene sorbitan, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitate tetraoleate, polyoxyethylene castor oil, polyoxyethylene hardened castor oil and the like. Among them, preferred surfactants include block copolymers of EO and PO (especially PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ether).

The weight average molecular weight (Mws) of the surfactant is typically less than 5,000, and preferably 4,000 or less (eg, 3,000 or less) from the viewpoint of filterability and washability. In addition, the Mws of the surfactant is usually suitably 200 or more from the viewpoint of surface activity and the like, and preferably 250 or more (for example, 300 or more) from the viewpoint of haze reduction effect and the like. A more preferable range of Mws of the surfactant may vary depending on the type of the surfactant. For example, when polyoxyethylene alkyl ether is used as a surfactant, its Mws is preferably 1,500 or less, and may be 1,000 or less (eg, 500 or less). Further, for example, when a PEO-PPO-PEO type triblock copolymer is used as a surfactant, its Mws may be, for example, 500 or more, 1,000 or more, or even 1,200 or more.

When the polishing composition according to some embodiments of the present invention contains a surfactant, its content is not particularly limited as long as it does not significantly impair the effects of the present invention. Usually, from the viewpoint of cleaning properties, it is appropriate to set the content of the surfactant to 100 parts by mass of the abrasive grains to 20 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less (e.g., 8 parts by mass or less). From the viewpoint of better exerting the effect of using the surfactant, the content of the surfactant with respect to 100 parts by mass of the abrasive grains is suitably 0.001 parts by mass or more, preferably 0.005 parts by mass or more, 0.01 parts by mass or more, or 0.05 parts by mass or more. In addition, when using 2 or more types of surfactant, the said content points out the total amount.

[Chelating agent]
Polishing compositions according to some embodiments of the present invention may contain a chelating agent. The chelating agent suppresses metal contamination on the surface of the object to be polished by trapping metal impurity components in the polishing system to form complexes.

Specific examples of chelating agents include aminocarboxylic acid-based chelating agents and organic phosphonic acid-based chelating agents. Specific examples of aminocarboxylic acid-based chelating agents include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate. Specific examples of organic phosphonic acid chelating agents include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1,-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, and ethane-1-hydroxy-1,1,2-triphosphonic acid. , ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, α-methylphosphonosuccinic acid and the like. Among these chelating agents, it is preferable to use an organic phosphonic acid-based chelating agent, particularly ethylenediaminetetrakis(methylenephosphonic acid). The chelating agents may be used singly or in combination of two or more.

[Other ingredients]
The polishing composition according to some embodiments of the present invention may further contain known additives such as organic acids, organic acid salts, inorganic acids, inorganic acid salts, preservatives, antifungal agents, etc., which can be used in polishing compositions (typically, polishing compositions used in the final polishing step of silicon wafers), as long as the effects of the present invention are not significantly hindered. Examples of organic acids include fatty acids such as formic acid, acetic acid and propionic acid, aromatic carboxylic acids such as benzoic acid and phthalic acid, citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, fumaric acid, succinic acid, organic sulfonic acids, and organic phosphonic acids. Examples of organic acid salts include alkali metal salts (sodium salt, potassium salt, etc.) and ammonium salts of organic acids. Examples of inorganic acids include sulfuric acid, nitric acid, hydrochloric acid, carbonic acid, and the like. Examples of inorganic acid salts include alkali metal salts (sodium salt, potassium salt, etc.) and ammonium salts of inorganic acids. The organic acid and its salt and the inorganic acid and its salt can be used singly or in combination of two or more. Examples of antiseptics and antifungal agents include isothiazoline compounds, paraoxybenzoic acid esters, phenoxyethanol and the like.

Polishing compositions according to some embodiments of the present invention are preferably substantially free of oxidizing agents. This is because if the polishing composition contains an oxidizing agent, the surface of the object to be polished (particularly a silicon wafer) is oxidized to form an oxide film, which prolongs the required polishing time. Specific examples of the oxidizing agent here include hydrogen peroxide (H ₂ O ₂ ), sodium persulfate, ammonium persulfate, sodium dichloroisocyanurate and the like. The polishing composition "substantially does not contain an oxidizing agent" means that it does not contain an oxidizing agent at least intentionally. Therefore, a trace amount of oxidizing agent (for example, the molar concentration of the oxidizing agent in the polishing composition is 0.001 mol/L or less, preferably 0.0005 mol/L or less, more preferably 0.0001 mol/L or less, still more preferably 0.00005 mol/L or less, and particularly preferably 0.00001 mol/L or less) derived from raw materials, manufacturing methods, etc. is unavoidable. It can be included in the concept of composition.

[Method for producing polishing composition]
The method for producing the polishing composition according to some embodiments of the invention is not particularly limited. For example, abrasive grains, a basic compound (ammonia, and at least one of a piperazine compound, an amine compound A, and an amine compound B), and other components added as necessary are sequentially added and stirred in a dispersion medium.

<Form etc. of Polishing Composition>
The polishing composition according to some embodiments of the present invention may be a one-component type, or may be a multi-component type composed of two or more components. In addition, the polishing composition described above may be used for polishing as it is, or the concentrated solution of the polishing composition may be diluted by adding water, or in the case of a multi-component polishing composition, it may be prepared by diluting with an aqueous solution containing water and a part of the constituent components and used for polishing. For example, after storing or transporting a concentrated solution of the polishing composition, the polishing composition can be prepared by diluting at the time of use.

The concentrated form of the polishing composition is advantageous from the viewpoint of convenience and cost reduction during production, distribution, storage, and the like. The concentration ratio can be, for example, about 2 times or more and 100 times or less in terms of volume, and usually about 5 times or more and 50 times or less is appropriate. The concentration ratio of the polishing composition according to a preferred embodiment is 10 times or more and 40 times or less, for example, 15 times or more and 25 times or less.

The polishing composition according to some embodiments of the present invention is preferably alkaline, and has a pH of preferably 8.0 or higher, more preferably 9.0 or higher, and even more preferably 9.5 or higher. As the pH of the polishing composition increases, the polishing rate tends to increase. On the other hand, the pH is preferably 12.0 or less, more preferably 11.0 or less, and even more preferably 10.8 or less. A lower pH of the polishing composition tends to improve surface accuracy.

That is, the pH of the polishing composition according to some embodiments of the present invention is preferably in the range of 8.0 to 12.0, more preferably in the range of 9.0 to 11.0, and even more preferably in the range of 9.5 to 10.8. Especially when the object to be polished is a silicon wafer, the pH of the polishing composition is preferably within the above range.

When the polishing composition is reused, it may be adjusted so that the pH falls within the above range, if necessary. For adjustment of pH, a known pH adjuster may be used, or the basic compound described above may be used. The pH value of the polishing composition can be confirmed with a pH meter. A detailed method for measuring pH is described in Examples.

[Object to be polished]
Objects to be polished using the polishing compositions according to some embodiments of the present invention are not particularly limited, and can be applied to polishing objects having various materials and shapes. Materials of the object to be polished include, for example, silicon materials, metals or semimetals such as aluminum, nickel, tungsten, steel, tantalum, titanium, and stainless steel, or alloys thereof; vitreous materials such as quartz glass, aluminosilicate glass, and vitreous carbon; ceramic materials such as alumina, silica, sapphire, silicon nitride, tantalum nitride, and titanium carbide; compound semiconductor substrate materials such as silicon carbide, gallium nitride, and gallium arsenide; Further, the object to be polished may be composed of a plurality of materials among the above materials.

Among these, the silicon material is preferable because the effects of the polishing composition according to some embodiments of the present invention can be obtained more remarkably. The polishing compositions according to some embodiments of the present invention are preferably used for polishing substrates having surfaces made of silicon materials.

Also, the silicon material preferably contains at least one material selected from the group consisting of silicon single crystal, amorphous silicon and polysilicon. As the silicon material, single crystal silicon or polysilicon is more preferable, and single crystal silicon is particularly preferable, from the viewpoint that the effects of the present invention can be obtained more remarkably. The polishing compositions according to some embodiments of the present invention are particularly preferably used for polishing a substrate (for example, a silicon wafer) having a silicon single crystal surface.

Furthermore, the shape of the object to be polished is not particularly limited. The polishing composition according to some embodiments of the present invention can be preferably applied to polishing objects having flat surfaces, such as plates and polyhedrons.

[Polishing method]
Another aspect of the present invention provides a polishing method comprising polishing an object to be polished using the polishing composition. The polishing composition according to some embodiments of the present invention is particularly suitable for use in the final polishing step because of its excellent haze reduction effect. That is, the polishing methods according to some embodiments of the present invention are preferably used in the final polishing process. Therefore, according to the present invention, there is also provided a method for manufacturing an object to be polished (for example, a method for manufacturing a silicon wafer) including a final polishing step using the polishing composition. Note that the final polishing step refers to the last polishing step in the manufacturing process of the object (that is, the step in which no further polishing is performed after that step). The polishing composition according to some embodiments of the present invention may also be used in a polishing step upstream of the finish polishing step (referring to a step between the rough polishing step and the final polishing step), for example, in a polishing step performed immediately before the finish polishing step.

The polishing compositions according to some embodiments of the present invention are preferably used for polishing silicon wafers, as described above. And, the polishing composition according to some embodiments of the present invention is particularly suitable as a polishing composition used in the final polishing step of silicon wafers. More specifically, the polishing composition according to some embodiments of the present invention is suitable for polishing a silicon wafer prepared to have a surface roughness of 0.01 nm or more and 100 nm or less by a process upstream of the final polishing process.

As the polishing apparatus, a general polishing apparatus can be used that has a holder that holds a substrate having an object to be polished, a motor that can change the number of rotations, and a polishing surface plate to which a polishing pad (abrasive cloth) can be attached.

As the polishing pad, a general non-woven fabric type, polyurethane type, suede type, etc. can be used without particular limitation. The polishing pad is preferably grooved so that the polishing composition is accumulated.

The polishing conditions are appropriately set depending on the stage of the polishing process in which the polishing composition is used.

In the pre-polishing step, either a double-sided polishing machine or a single-sided polishing machine may be used, but a double-sided polishing machine can be preferably used. The rotation speed of the platen is usually about 10 rpm to 100 rpm, preferably about 20 rpm to 50 rpm. When using a double-sided polishing apparatus, the rotation speeds of the upper rotary platen and the lower rotary platen may be different, but they are usually set to the same relative speed with respect to the wafer. In the final polishing step, a single-sided polishing apparatus can be suitably used, and the rotation speed of the surface plate is usually about 10 rpm to 100 rpm, preferably about 20 rpm to 50 rpm, more preferably about 25 rpm to 50 rpm. With such a rotation speed, the haze level on the surface of the object to be polished can be significantly reduced.

The object to be polished is usually pressurized by a surface plate. The pressure at this time can be appropriately selected, but in the pre-polishing step, it is generally preferably about 5 kPa or more and 30 kPa or less, more preferably about 10 kPa or more and 25 kPa or less. In the case of the final polishing step, the pressure is preferably about 5 kPa or more and 30 kPa or less, more preferably about 10 kPa or more and 20 kPa or less. Such a pressure can significantly reduce the haze level on the surface of the object to be polished.

The supply rate of the polishing composition can also be appropriately selected according to the size of the platen, but in the case of the preliminary polishing step, it is usually preferably about 0.1 L/min or more and 5 L/min or less, preferably about 0.2 L/min or more and 2 L/min or less. In the case of the final polishing step, the flow rate is generally preferably about 0.1 L/min or more and 5 L/min or less, preferably about 0.2 L/min or more and 2 L/min or less. With such a supply rate, the surface of the object to be polished can be efficiently polished, and the haze level of the surface of the object to be polished can be significantly reduced.

The holding temperature of the polishing composition in the polishing apparatus is not particularly limited, but from the viewpoint of the stability of the polishing rate and the reduction of the haze level, it is generally preferably about 15°C or more and 40°C or less, more preferably about 18°C or more and 25°C or less.

The above polishing conditions (polishing device settings) are merely examples, and may be outside the above range, and the settings can be changed as appropriate. Such conditions can be appropriately set by those skilled in the art.

Furthermore, it is preferable to wash and dry after polishing. Methods and conditions for these operations are not particularly limited, and known ones are appropriately employed. For example, it is preferable to perform SC-1 cleaning as the step of cleaning the object to be polished. “SC-1 cleaning” is a cleaning method that uses, for example, a mixture of ammonia and hydrogen peroxide (eg, 40° C. or higher and 80° C. or lower). By performing SC-1 cleaning, the surface of the silicon wafer can be thinly etched and particles on the surface of the silicon wafer can be removed.

Although the embodiments of the present invention have been described in detail, it is clear that this is illustrative and exemplary rather than limiting, and that the scope of the present invention should be construed by the appended claims.

The present invention includes the following aspects and forms.
1. including abrasive grains and a basic compound,
The basic compound contains ammonia and a piperazine compound,
A polishing composition in which the content C1 of the piperazine compound represented by the following formula (1) is more than 0% and 5.5% or less, where A1 (unit: mass %) is the content of the ammonia in the polishing composition and B1 (unit: mass %) is the content of the piperazine compound in the polishing composition;

2. 1. The content of the piperazine compound C1 is 1.0% or more and 4.0% or less. The polishing composition according to;
3. 1. The piperazine compound is at least one selected from the group consisting of 1-methylpiperazine, 1-(2-aminoethyl)piperazine, 1,4-dimethylpiperazine, and 1,4-bis(3-aminopropyl)piperazine. or 2. The polishing composition according to;
4. 1. above, further comprising a dispersion medium. ~3. The polishing composition according to any one of;
5. including abrasive grains and a basic compound,
The basic compound contains ammonia and an amine compound A having two or more nitrogen atoms and a pKa higher than that of the ammonia,
When the content of the ammonia in the polishing composition is A2 (unit: mass %) and the content of the amine compound A in the polishing composition is B2 (unit: mass %), the content C2 of the amine compound A represented by the following formula (2) is more than 0% and 5.5% or less;

6. 5. The content C2 of the amine compound A is 1.0% or more and 4.0% or less. The polishing composition according to;
7. 5. The amine compound A is at least one selected from the group consisting of trans-1,2-cyclohexyldiamine and ethylenediamine. or 6. The polishing composition according to;
8. 5. above, further comprising a dispersion medium. ~7. The polishing composition according to any one of;
9. including abrasive grains and a basic compound,
The basic compound contains ammonia and an amine compound B that has one nitrogen atom and has a higher pKa than the ammonia,
The amine compound B is a secondary amine or a tertiary amine,
When the content of the ammonia in the polishing composition is A3 (unit: mass %) and the content of the amine compound B in the polishing composition is B3 (unit: mass %), the content C3 of the amine compound B represented by the following formula (3) is more than 0% and 35% or less;

10. 9. The content C3 of the amine compound B is 1.0% or more and 15.0% or less. The polishing composition according to;
11. 9. The amine compound B is at least one selected from the group consisting of piperidine, N-methylpiperidine, triethylamine, and N-methylpyrrolidine. or 10. The polishing composition according to;
12. 9. above, further comprising a dispersion medium. ~ 11. The polishing composition according to any one of;
13. The above 1. used for polishing a substrate having a surface made of a silicon material. ~12. The polishing composition according to any one of;
14. 1 above. ~ 13. A concentrate of the polishing composition according to any one of;
15. 1 above. ~ 13. A polishing method comprising polishing an object to be polished using the polishing composition according to any one of the above.

The present invention will be explained in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass" respectively. Moreover, in the following examples, unless otherwise specified, the operations were carried out under the conditions of room temperature (25° C.)/relative humidity of 40% RH or more and 50% RH or less.

<Average primary particle size of silica>
The average primary particle size of silica was calculated from the specific surface area of colloidal silica measured by the BET method using a surface area measuring device manufactured by Micromeritex under the trade name “Flow Sorb II 2300” and the true density of colloidal silica.

<pH of Polishing Composition>
The pH was measured using a pH meter (glass electrode type hydrogen ion concentration indicator (model number F-2372) manufactured by Horiba, Ltd.). More specifically, standard buffer solutions (phthalate pH buffer pH: 4.01 (25 ° C.), neutral phosphate pH buffer pH: 6.86 (25 ° C.), carbonate pH buffer pH: 10.01 (25 ° C.)) were used to perform three-point calibration, the glass electrode was placed in the polishing composition to be measured, and the value after 2 minutes or more had passed and stabilized was measured.

<Measurement of weight average molecular weight>
The weight average molecular weights of water-soluble polymers and surfactants were measured using the GPC method under the following conditions:
≪GPC measurement conditions≫
Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)
Sample concentration: 0.1% by mass
Column: TSKgel GMPWXL
Detector: Differential refractometer Eluent: 100 mM sodium nitrate aqueous solution/acetonitrile = 10 to 8/0 to 2
Flow rate: 1 mL/min Measurement temperature: 40°C
Molecular weight conversion: Polyethylene glycol conversion Sample injection volume: 100 μL.

<pKa of amine compound>
The pKa of the amine compound was calculated from a neutralization titration curve obtained by titrating a 0.1% by mass aqueous solution of the amine compound with 0.5M (mol/L) hydrochloric acid using a Hiranuma automatic titrator (manufactured by Hitachi High-Tech Co., Ltd.). The pKa of ammonia calculated by this method is 9.35.

(Examples 1 to 22, Comparative Examples 1 to 13)
Each component (abrasive grains, dispersion medium, ammonia, piperazine compound, amine compound A, amine compound B) was mixed to prepare concentrated solutions of the polishing compositions of Examples 1 to 22 and Comparative Examples 1 to 13. Polishing compositions of Examples 1 to 22 and Comparative Examples 1 to 13 were obtained by diluting the obtained concentrates with water. The composition of the polishing composition is as shown in Tables 1 to 3 below. Table 1 shows Examples and Comparative Examples relating to the first polishing composition, Table 2 shows Examples and Comparative Examples relating to the second polishing composition, and Table 3 shows Examples and Comparative Examples relating to the third polishing composition.

Colloidal silica with an average primary particle diameter of 25 nm was used as abrasive grains. The content of abrasive grains is 0.169% by mass. Water was used as a dispersion medium.

The details of the ammonia content and the type and content of the piperazine compound, amine compound A, or amine compound B are shown in Tables 1 to 3 below. Comparative Example 5 is an example in which no piperazine compound is added and only ammonia is added as a basic compound, and Comparative Examples 6 and 10 are examples in which ammonia is not added. The pH values of the polishing compositions of Examples 1 to 22 and Comparative Examples 1 to 13 are shown in Tables 1 to 3 below.

[Evaluation of Etching Rate]
[Etching rate measurement]
As a wafer seed, a p-type COP-free silicon wafer having a <100> crystal orientation and a size of 3 cm×6 cm was prepared.

After measuring the weight of the silicon wafer before immersion, the wafer was immersed in a cleaning solution of NH ₄ OH (29%): H ₂ O ₂ (31%): deionized water (DIW) = 1:1:8 (volume ratio) for 30 seconds and washed with ultrapure water.

After that, the wafer was immersed in HF (3% by mass) for 30 seconds, washed with ultrapure water, immersed in each slurry, and allowed to stand at 25°C for 40 hours. The wafer was taken out, washed with ultrapure water, and dried.

The weight of the silicon wafer after immersion was measured. From the weight of the wafer before and after immersion, the surface area of the wafer, and the specific gravity of silicon, the etching rate R was calculated based on the following equations (A) to (C). The specific gravity of silicon used was 2.33.

Tables 1 to 3 below show the relative values of the etching rate of each example and comparative example with respect to the etching rate of comparative example 5.

As is clear from Tables 1 to 3 above, the polishing compositions of Examples 1 to 22 have a higher etching rate than the polishing compositions of Comparative Examples 1 to 13, and the object to be polished can be polished at a high polishing rate.

(Examples 23 to 26, Comparative Example 14)
Concentrated solutions of the polishing compositions of Examples 23 to 26 and Comparative Example 14 were prepared by mixing each component (abrasive grains, dispersion medium, ammonia, piperazine compound, water-soluble polymer, surfactant). Polishing compositions of Examples 23 to 26 and Comparative Example 14 were obtained by diluting the obtained concentrates with water. The composition of the polishing composition is as shown below:
Abrasive grains: 0.169% by mass of colloidal silica with an average primary particle diameter of 25 nm
Dispersion medium: water First water-soluble polymer: Poly N-acryloylmorpholine (PACMO) having a weight average molecular weight (Mw) of 4.7×10 ⁵ 0.008% by mass
Second water-soluble polymer: 0.0025% by mass of acetalized modified polyvinyl alcohol (PVA) having a weight average molecular weight (Mw) of 1.0×10 ⁴
First surfactant: polyoxyethylene decyl ether (ethylene oxide addition mole number 5, molecular weight 378) 0.0008% by mass
Second surfactant: polyethylene oxide (PEO)-polypropylene oxide (PPO)-polyethylene oxide (PEO) type triblock copolymer having a weight average molecular weight (Mw) of 3×10 ³ 0.0004% by mass
Details of the content of ammonia and the type and content of the piperazine compound are shown in Table 4 below. Comparative Example 14 is an example in which no piperazine compound was added and only ammonia was added as a basic compound. The pH values of the polishing compositions of Examples 23 to 26 and Comparative Example 14 are shown in Table 4 below.

[Surface quality (haze) and polishing speed]
<Measurement of haze>
As a wafer type, a p-type COP (Crystal Orginated Particle)-free silicon wafer having a <100> crystal orientation and a size of 300 mm was prepared. Here, a COP is a concave defect formed on the surface of a silicon wafer, and is caused by a crystal defect of single crystal silicon forming the silicon wafer or a scratch exceeding a certain width and depth caused by an abrasive (abrasive grain).

≪Preliminary Polishing≫
The above silicon wafers were polished under the following pre-polishing conditions:
(Conditions for preliminary polishing)
Polishing device: Sheet-fed polishing machine manufactured by Okamoto Machine Tool Co., Ltd., model "PNX-332B"
Polishing load: 20kPa
Surface plate rotation speed: 20 rpm
Carrier rotation speed: 20 rpm
Polishing pad: Product name “SUBA400” manufactured by Nitta DuPont Co., Ltd.
Polishing composition supply rate: 1 L/min
Temperature of polishing composition: 20°C
Surface plate cooling water temperature: 20°C
Polishing time: 3 minutes Polishing composition for preliminary polishing: 1.0% by mass of colloidal silica (average primary particle diameter: 35 nm), 0.068% by mass of KOH, dispersion medium: water.

≪Finish polishing≫
Silicon wafers polished by the above preliminary polishing were polished under the following final polishing conditions:
(Conditions for final polishing)
Polishing device: Sheet-fed polishing machine manufactured by Okamoto Machine Tool Co., Ltd., model "PNX-332B"
Polishing load: 10kPa
Surface plate rotation speed: 52 rpm
Carrier rotation speed: 50 rpm
Polishing pad: Product name “POLYPAS275NX” manufactured by Fujibo Ehime Co., Ltd.
Polishing composition supply rate: 1.5 L/min
Temperature of polishing composition: 20°C
Surface plate cooling water temperature: 20°C
Polishing time: 4 minutes Polishing composition for final polishing: Polishing compositions of Examples 23 to 26 and Comparative Example 14 shown in Table 4 below.

The silicon wafers polished by the above final polishing were cleaned under the following cleaning conditions:
(Washing conditions)
A first cleaning bath containing a cleaning solution of NH ₄ OH (29%):H ₂ O ₂ (31%):deionized water (DIW)=2:5.3:48 (volume ratio) and a second cleaning bath containing ultrapure water at 25° C. were prepared. The polished silicon wafer was immersed in the first cleaning bath for 6 minutes and then immersed in the second cleaning bath for 15 minutes. After that, the silicon wafer was again immersed in the first cleaning bath for 6 minutes, immersed in the second cleaning bath for 16 minutes, and then dried.

The haze of the silicon wafer after drying was measured in DW2O mode using a wafer inspection device (manufactured by KLA-Tencor Co., Ltd., product name "SURFSCAN SP5"). Table 4 below shows the haze values of Examples 23 to 26 relative to those of Comparative Example 14.

<Measurement of Polishing Rate>
As a wafer seed, a p-type COP (Crystal Orginated Particle) free silicon wafer having a <100> crystal orientation and a size of 200 mm was prepared. The prepared silicon wafer was polished under the following polishing conditions.

(polishing conditions)
Polishing device: Sheet-fed polishing machine manufactured by Okamoto Machine Tool Co., Ltd., model "PNX-322"
Polishing load: 10kPa
Surface plate rotation speed: 30 rpm
Carrier rotation speed: 30 rpm
Polishing pad: Product name “POLYPAS275NX” manufactured by Fujibo Ehime Co., Ltd.
Polishing composition supply rate: 0.4 L/min
Temperature of polishing composition: 20°C
Surface plate cooling water temperature: 20°C
Polishing time: 10 minutes Polishing composition: Polishing compositions of Examples 23 to 26 and Comparative Example 14 shown in Table 4 below.

The silicon wafers polished under the above polishing conditions were washed under the following washing conditions:
(Washing condition)
After polishing, the silicon wafer was cleaned by immersing it in a cleaning solution of NH ₄ OH (29%):H ₂ O ₂ (31%):deionized water (DIW)=1:1:12 (volume ratio) for 5 minutes (SC-1 cleaning). After that, the silicon wafer was immersed in ultrapure water and dried with a spin drier while the ultrasonic oscillator was in operation.

The polishing rate was calculated from the difference in weight of the silicon wafer before and after polishing and the specific gravity of silicon. Table 4 below shows the relative values of the polishing rates of Examples 23 to 26 with respect to the polishing rate of Comparative Example 14.

As is clear from Table 4 above, when the polishing compositions of Examples 23 to 26 were used, compared to the polishing composition of Comparative Example 14, it was found that the object to be polished could be polished at a higher polishing rate. Moreover, it was found that when the polishing compositions of Examples 23 to 26 were used, the surface quality of the object to be polished after polishing could be maintained satisfactorily.

(Examples 27 to 39, Comparative Example 15)
Each component (abrasive grain, dispersion medium, ammonia, piperazine compound, amine compound A, amine compound B, water-soluble polymer, surfactant) was mixed to prepare a concentrated solution of the polishing composition of Examples 27 to 39 and Comparative Example 15. Polishing compositions of Examples 27 to 39 and Comparative Example 15 were obtained by diluting the obtained concentrates with water. The composition of the polishing composition is as shown below:
Abrasive grains: 0.17% by mass of colloidal silica with an average primary particle diameter of 25 nm
Dispersion medium: water First water-soluble polymer: Poly N-acryloylmorpholine (PACMO) having a weight average molecular weight (Mw) of 4.7×10 ⁵ 0.008% by mass
Second water-soluble polymer: 0.003% by mass of acetalized modified polyvinyl alcohol (PVA) having a weight average molecular weight (Mw) of 1.0×10 ⁴
First surfactant: polyoxyethylene decyl ether (ethylene oxide addition mole number 5, molecular weight 378) 0.0008% by mass
Second surfactant: Polyethylene oxide (PEO)-polypropylene oxide (PPO)-polyethylene oxide (PEO) type triblock copolymer having a weight average molecular weight (Mw) of 3×10 ³ 0.0004% by mass.

Details of the content of ammonia, and the types and content of the piperazine compound, amine compound A, and amine compound B are shown in Table 5 below. Comparative Example 15 is an example in which no piperazine compound was added and only ammonia was added as a basic compound. The pH values of the polishing compositions of Examples 27 to 39 and Comparative Example 15 are shown in Table 5 below.

[Surface quality (haze) and polishing speed]
<Measurement of haze>
As a wafer type, a p-type COP (Crystal Orginated Particle)-free silicon wafer having a <100> crystal orientation and a size of 300 mm was prepared.

≪Finish polishing≫
Silicon wafers polished by the above preliminary polishing were polished under the following final polishing conditions:
(Conditions for final polishing)
Polishing device: Sheet-fed polishing machine manufactured by Okamoto Machine Tool Co., Ltd., model "PNX-332B"
Polishing load: 20kPa
Surface plate rotation speed: 52 rpm
Carrier rotation speed: 50 rpm
Polishing pad: Product name “POLYPAS275NX” manufactured by Fujibo Ehime Co., Ltd.
Polishing composition supply rate: 1.5 L/min
Temperature of polishing composition: 20°C
Surface plate cooling water temperature: 20°C
Polishing time: 4 minutes Polishing composition for final polishing: Polishing compositions of Examples 27 to 39 and Comparative Example 15 shown in Table 5 below.

The silicon wafers polished by the above final polishing were cleaned under the following cleaning conditions:
(Washing conditions)
After polishing, the silicon wafer was removed from the polishing apparatus, washed with an ozone water cleaning solution (60 seconds) using a single wafer cleaning apparatus, then cleaned with an SC-1 cleaning solution and a brush (110 seconds), then washed with an ozone water cleaning solution (20 seconds) and with a hydrofluoric acid cleaning solution (15 seconds) as one set. The silicon wafer was then dried.

The haze of the silicon wafer after drying was measured in DW2O mode using a wafer inspection device (manufactured by KLA-Tencor Co., Ltd., product name "SURFSCAN SP5"). Table 5 below shows the haze values of Examples 27 to 39 relative to those of Comparative Example 15.

<Measurement of Polishing Rate>
As a wafer type, a p-type COP (Crystal Orginated Particle)-free silicon wafer having a <100> crystal orientation and a size of 300 mm was prepared. The prepared silicon wafer was polished under the following polishing conditions.

(polishing conditions)
Polishing device: Sheet-fed polishing machine manufactured by Okamoto Machine Tool Co., Ltd., model "PNX-322"
Polishing load: 20kPa
Surface plate rotation speed: 52 rpm
Carrier rotation speed: 50 rpm
Polishing pad: Product name “POLYPAS275NX” manufactured by Fujibo Ehime Co., Ltd.
Polishing composition supply rate: 0.75 L/min
Temperature of polishing composition: 20°C
Surface plate cooling water temperature: 20°C
Polishing time: 10 minutes Polishing composition: Polishing compositions of Examples 27 to 39 and Comparative Example 15 shown in Table 5 below.

The silicon wafers polished under the above polishing conditions were washed under the following washing conditions:
(Washing condition)
After polishing, the silicon wafer was immersed in ozone water for 15 minutes, then immersed in ultrapure water, and then dried with a spin dryer.

The polishing rate was calculated from the difference in weight of the silicon wafer before and after polishing and the specific gravity of silicon. Table 5 below shows the relative values of the polishing rates of Examples 27 to 39 with respect to the polishing rate of Comparative Example 15.

As is clear from Table 5 above, when the polishing compositions of Examples 27 to 39 were used, the object to be polished could be polished at a higher polishing rate than the polishing composition of Comparative Example 15. Moreover, it was found that when the polishing compositions of Examples 27 to 39 were used, the surface quality of the object to be polished after polishing could be maintained in good condition.

This application is based on Japanese Patent Application No. 2022-007831 filed on January 21, 2022 and Japanese Patent Application No. 2022-156141 filed on September 29, 2022, the disclosure of which is incorporated by reference in its entirety.

Claims

including abrasive grains and a basic compound,
The basic compound contains ammonia and a piperazine compound,
When the content of the ammonia in the polishing composition is A1 (unit: mass %) and the content of the piperazine compound in the polishing composition is B1 (unit: mass %), the content C1 of the piperazine compound represented by the following formula (1) is more than 0% and 5.5% or less.
The polishing composition according to claim 1, wherein the piperazine compound content C1 is 1.0% or more and 4.0% or less.
The polishing composition according to claim 1, wherein the piperazine compound is at least one selected from the group consisting of 1-methylpiperazine, 1-(2-aminoethyl)piperazine, 1,4-dimethylpiperazine, and 1,4-bis(3-aminopropyl)piperazine.
The polishing composition according to claim 1, further comprising a dispersion medium.
including abrasive grains and a basic compound,
The basic compound contains ammonia and an amine compound A having two or more nitrogen atoms and a pKa higher than that of the ammonia,
When the content of the ammonia in the polishing composition is A2 (unit: mass %) and the content of the amine compound A in the polishing composition is B2 (unit: mass %), the following formula (2) A polishing composition in which the content C2 of the amine compound A is more than 0% and 5.5% or less.
The polishing composition according to claim 5, wherein the content C2 of the amine compound A is 1.0% or more and 4.0% or less.
The polishing composition according to claim 5, further comprising a dispersion medium.
including abrasive grains and a basic compound,
The basic compound contains ammonia and an amine compound B that has one nitrogen atom and has a higher pKa than the ammonia,
The amine compound B is a secondary amine or a tertiary amine,
When the content of the ammonia in the polishing composition is A3 (unit: mass%) and the content of the amine compound B in the polishing composition is B3 (unit: mass%), the following formula (3) A polishing composition in which the content C3 of the amine compound B is more than 0% and 35% or less.
The polishing composition according to claim 8, wherein the content C3 of the amine compound B is 1.0% or more and 15.0% or less.
The polishing composition according to claim 8, further comprising a dispersion medium.
The polishing composition according to any one of claims 1 to 10, which is used for polishing a substrate having a surface made of a silicon material.
A concentrated liquid of the polishing composition according to any one of claims 1 to 10.
A polishing method comprising polishing an object to be polished using the polishing composition according to any one of claims 1 to 10.