TW202220046A - Grinding composition and use thereof - Google Patents

Abstract

Provided is a novel grinding composition suited to grinding. The grinding composition contains a basic compound and water. The grinding composition further contains a surfactant having two hydrophilic bases and two hydrophobic bases in the molecule.

Description

Polishing composition and its utilization

The present invention relates to a polishing composition and a polishing method using the polishing composition. This application claims priority based on Japanese Patent Application No. 2020-163194 for which it applied on September 29, 2020, the entire content of which is incorporated herein by reference.

Conventionally, the surfaces of materials such as metals, semi-metals, non-metals, and oxides thereof have been precisely polished using polishing compositions. For example, the surface of a silicon wafer used as a member of a semiconductor product or the like generally undergoes a rough grinding step (rough grinding step) and a polishing step (fine grinding step) to obtain a high-quality mirror surface. The above-mentioned polishing step typically includes a pre-polishing step (pre-grinding step) and a finishing polishing step (final grinding step). [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2019-142825

[Problems to be solved by the invention]

As the polishing composition, a composition having a polishing ability to efficiently polish the object to be polished can be used. For example, when polishing a semiconductor substrate such as the above-mentioned silicon wafer or other substrates, a chemical polishing action (alkali etching) by an alkaline compound can be utilized. In the above-mentioned grinding, abrasive grains can be used as necessary. In addition to the above-mentioned chemical polishing action, the mechanical polishing action of the abrasive grains can exert a higher processing ability. In addition, the polishing composition used for the polishing of the above-mentioned substrate may be required to realize high-quality surface performance after polishing. The improvement of the surface quality of a polishing surface can be achieved by the method of making a polishing composition contain additives, such as surfactant, and protecting a board|substrate etc. with the said additive. However, the use of the above-mentioned additives may lead to a decrease in processing ability, and it is not easy to balance the quality of the polished surface and the polishing rate. In the above-mentioned polishing field, polishing components have been examined from various viewpoints. For example, a composition that can balance the improvement of the polishing surface quality and the polishing rate, which are generally considered to be mutually compensatory as described above, is being investigated. review.

The present invention has been made against the above-mentioned background and aims to provide a novel composition suitable for grinding. [Means for solving problems]

According to this specification, a polishing composition can be provided. The polishing composition contains a basic compound and water. Furthermore, a surfactant having two hydrophilic groups and two hydrophobic groups in one molecule is further included. According to this composition, by the action of a surfactant with a specific structure having two hydrophilic groups and two hydrophobic groups in one molecule, the chemical polishing effect generated by the basic compound can be well exerted, and at the same time, the Maintain or improve the surface quality of the abrasive surface. That is, a composition suitable for grinding can be provided.

Among several suitable aspects, by using a compound represented by the following formula (1) as a surfactant, it is easy to balance a high-quality polishing surface and a polishing rate in a balanced manner. Here, the compound represented by the following formula (1) includes a compound called a gemini-type surfactant.

(式(1)中，R ¹、R ²各自獨立地為烷基，R ³、R ⁴各自獨立地為氫原子或氧伸烷基單元)

(In formula (1), R ¹ and R ² are each independently an alkyl group, and R ³ and R ⁴ are each independently a hydrogen atom or an oxyalkylene unit)

In addition, Patent Document 1 discloses a composition containing a gemini-type anionic surfactant and is listed in the prior art document, however, it is a prior art document concerning a cosmetic containing a whitening agent, not a polishing composition. literature.

In several suitable aspects, the polishing composition further comprises abrasive particles. By including the abrasive grains in the polishing composition, the polishing rate can be increased by the mechanical polishing action of the contained abrasive grains. By making the composition including the abrasive grains and the basic compound contain the surfactant of the above-mentioned specific structure, the surface quality after polishing can be maintained or improved, and the polishing rate can be increased at the same time. As the above-mentioned abrasive grains, silica particles are preferably used. By using silica particles as abrasive grains, it is easy to balance high-quality polishing surface and polishing rate. The effect of the surfactant containing the above-mentioned specific structure can be suitably achieved in a polishing composition containing silica particles as abrasive grains.

In several suitable aspects, the polishing composition further contains a water-soluble polymer. A high-quality polished surface can be appropriately achieved by the composition including the surfactant of the specific structure described above and a water-soluble polymer.

In several suitable aspects, the pH of the above-mentioned polishing composition is 8.0 or more and 12.0 or less. When the pH of the composition is within the above-mentioned range, the effects of the technique disclosed herein can be appropriately exerted.

The polishing composition disclosed herein is suitable for polishing silicon wafers. By using the above-mentioned polishing composition to polish the silicon wafer, the surface quality after polishing can be maintained or improved, which is suitable for realizing a high-quality silicon wafer surface. In particular, the polishing compositions disclosed herein are suitable for use in finishing polishing steps for silicon wafers.

In addition, according to this specification, there can be provided a method for polishing a substrate using any of the polishing compositions disclosed herein. The above-mentioned grinding method includes a polishing step. In the polishing step described above, the substrate is polished using a polishing composition comprising the surfactant of the specific structure described above, an alkaline compound, and water. The polishing method provided by this specification is, in several aspects, a polishing method for silicon wafers. That is, the effects produced by the techniques disclosed herein can be appropriately achieved in the grinding of silicon wafers. In several suitable aspects, the above-described grinding method includes a pre-polishing step and a finish polishing step. Then, in the above-mentioned finishing polishing step, polishing is performed using the polishing composition disclosed herein. According to the grinding method, in the above-mentioned finishing polishing step, the surface of the silicon wafer of higher quality can be efficiently obtained.

Hereinafter, preferred embodiments of the present invention will be described. In addition, in the present specification, matters other than the matters specifically mentioned and necessary for implementing the present invention can be grasped by those in the art based on the design matters of the prior art in the field. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the field.

<Surfactant A> The polishing composition disclosed here is characterized by including a surfactant (hereinafter, also referred to as "surfactant A" for convenience) having two hydrophilic groups and two hydrophobic groups in one molecule. When polishing using the polishing composition containing the surfactant A of the above-mentioned specific structure, the chemical polishing action by the basic compound described later can be well exhibited, and the surface quality of the polishing surface can be maintained or improved. The reason for this is considered to be that the surfactant A with the above-mentioned specific structure does not excessively inhibit the alkali etching caused by the basic compound compared with the surfactant having one hydrophilic group and one hydrophobic group, and appropriately protects the surface active agent A. substrate surface. In addition, the role of surfactant A is not limited to the above-mentioned role. The surfactant A may be used alone or in combination of two or more.

As the surfactant A, any of anionic, cationic, nonionic, and amphoteric can be used. In particular, anionic or nonionic surfactant A is suitable. From the viewpoint of improving the surface quality, the nonionic surfactant A is preferable.

For the surfactant A, for example, a compound having a structure in which at least two structural units (typically, chain structural units) are linked, and the structural unit has a hydrophilic group and a hydrophobic group, and the above-mentioned at least The two structural units are linked in a state of having the hydrophilic group and the hydrophobic group. In this way, the surfactant A has two hydrophilic groups and two hydrophobic groups in one molecule. In the above-mentioned surfactant A, a plurality of structural units having one hydrophilic group and one hydrophobic group can be bonded to each other through covalent bonds. The form of the covalent bond is not particularly limited, and the atoms (typically, carbon atoms) constituting each of the above-mentioned structural units are linked by covalent bonds, or can be linked through ester bonds, ether bonds, amide bonds, etc., or can be linked together. It is linked through a divalent organic group such as a phenylene group. The above-mentioned plural structural units (structural units having one hydrophilic group and one hydrophobic group) contained in the surfactant A may be the same or different.

The hydrophilic group constituting the surfactant A includes a polar group or an ionic group. Specific examples include organic functional groups such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, an ammonium group, an amino group, and an amide group. Among several aspects, the above-mentioned hydrophilic group is preferably a carboxyl group. In addition, the two hydrophilic groups contained in the surfactant A may be the same or different.

Among other aspects, the above-mentioned hydrophilic group is preferably constituted by including an oxyalkylene unit. The above-mentioned hydrophilic group may be constituted by one oxyalkylene group, or may be a repeating structure of two or more oxyalkylene units. Alternatively, one or more oxyalkylene units may be added to the organic functional group as the above-mentioned hydrophilic group. As an example of an oxyalkylene unit, an oxyethylene unit (EO) or an oxypropylene unit (PO) is mentioned. In particular, oxyethylene units (EO) are preferred. When the above-mentioned two hydrophilic groups have a plurality of oxyalkylene units, the oxyalkylene units may be the same type (ie, one type), or may be constituted by including two or more oxyalkylene units. When at least one (for example, both) of the two hydrophilic groups contained in the surfactant A contains an oxyalkylene unit, the sum of the alkylene oxides contained in the surfactant A is added to the molar The number may be 1 or more or 3 or more, 5 or more, 10 or more, 15 or more, 20 or more, and may be 50 or less or 30 or less, 22 or less, 16 or less, 12 or less, 8 or less, 4 or less (for example, 3 or less) . In the case where each of the above-mentioned two hydrophilic groups has an oxyalkylene unit, the added molar numbers of the alkylene oxides contained in each of the two hydrophilic groups may be the same or different.

The hydrophobic group constituting the surfactant A includes a hydrocarbon group, an acyl group, and the like. The hydrocarbon group or the acyl group may be composed of a saturated hydrocarbon such as an alkyl group, or may contain an unsaturated bond such as a carbon-carbon double bond. In addition, a hydrocarbon group (typically an alkyl group) or an acyl group may be either a straight chain or a branched one. The number of carbon atoms contained in one hydrophobic group (for example, a hydrocarbon group such as an alkyl group) contained in the surfactant A may be 8 or more, 10 or more, and 12 or more, and may also be 24 or less, 20 or less, 18 or less, or 16 below, 12 or below. Specific examples of the hydrophobic group include octyl, decyl, lauryl, myristyl, palmityl, stearyl, octyl, decyl, lauryl, myristyl, palmityl and the like. . The two hydrophobic groups contained in the surfactant A may be the same or different.

The above-mentioned surfactant A may be a compound called a gemini-type surfactant. As the surfactant A disclosed here, known gemini-type surfactants can be used. Such gemini surfactants include compounds called dicarboxylic acid-based gemini surfactants, gemini surfactants containing bisquaternary ammonium salts, and amino acid-based gemini surfactants . As the surfactant A, one kind or two or more kinds of gemini surfactants can be used.

Suitable examples of the surfactant A include compounds represented by the following general formula (1).

In the above formula (1), R ¹ and R ² are each independently an alkyl group. The alkyl group that can be R ¹ and R ² may have 8 or more, 10 or more, or 12 or more carbon atoms, and may be 24 or less, 20 or less, 18 or less, 16 or less, or 12 or less. Specific examples of the alkyl group include an octyl group, a decyl group, a lauryl group, a myristyl group, a palmityl group, a stearyl group, and the like. R ¹ and R ² may be the same or different.

In the above formula (1), R ³ and R ⁴ are each independently a hydrogen atom or an oxyalkylene unit. R ³ and R ⁴ may be the same or different. Where at least one (eg, both) of R ³ and R ⁴ includes an oxyalkylene unit, the oxyalkylene unit may be an oxyethylene unit (EO) or an oxypropylene unit (PO) . Oxyethylene units (EO) are preferred. The oxyalkylene units contained in R ³ and R ⁴ may be one type (for example, only EO) or two or more types (for example, EO and PO). The total number of added moles of alkylene oxides contained in R ³ and R ⁴ may be 1 or more, 3 or more, 5 or more, 10 or more, 15 or more, and 20 or more, and may be 50 or less, 30 or less, or 22 below, 16 or below, 12 or below, 8 or below, 4 or below (for example, 3 or below). When both R ³ and R ⁴ contain an oxyalkylene unit, the added molar numbers of the alkylene oxides contained in R ³ and R ⁴ may be the same or different.

As the surfactant A, a compound having an appropriate molecular weight for exerting its function in the polishing composition can be used, and is not limited to a specific molecular weight. The molecular weight of the surfactant A is, for example, 300 or more, preferably 400 or more, preferably 500 or more, or may be 700 or more, 1200 or more, or 1500 or more. The upper limit of the molecular weight is, for example, 3,000 or less, preferably 2,000 or less, or 1,400 or less, 1,000 or less, or 600 or less. As the molecular weight of the surfactant A, the molecular weight calculated from the chemical formula can be used.

The content of the surfactant A in the polishing composition may be, for example, 1.0×10 ⁻⁶ wt % or more from the viewpoint of exhibiting the effect of adding the surfactant A, and from the viewpoint of the surface quality after polishing It is preferably 1.0 × 10 ^-5 wt % or more, preferably 1.0 × 10 ^-4 wt % or more, more preferably 5.0 × 10 ^-4 wt % or more, particularly preferably 1.0 × 10 ^-3 wt % or more, or 3.0×10 ⁻³ wt % or more. In addition, the content of the surfactant A in the polishing composition is preferably set to less than 0.2 wt % from the viewpoint of detergency and the like, and may be less than 0.1 wt %, preferably 0.05 wt % or less , preferably 0.01 wt % or less, or may be 0.005 wt % or less, or 0.003 wt % or less. These contents are suitably used, for example, in the polishing liquid (working slurry) supplied to the substrate.

＜Basic compound＞ The polishing composition disclosed here contains a basic compound. In the present specification, a basic compound refers to a compound having a function of being dissolved in water to raise the pH of an aqueous solution. By containing the basic compound in the polishing composition, the object to be polished is efficiently polished by its chemical polishing action (alkali etching). As the basic compound, nitrogen-containing organic or inorganic basic compounds, phosphorus-containing basic compounds, alkali metal hydroxides, alkaline earth metal hydroxides, various carbonates or bicarbonates, and the like can be used. Examples of the nitrogen-containing basic compound include quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), and the like. Examples of phosphorus-containing basic compounds include quaternary phosphonium compounds. Such basic compounds may be used alone or in combination of two or more.

Specific examples of the alkali metal hydroxide include potassium hydroxide, sodium hydroxide, and the like. Specific examples of carbonate or bicarbonate include ammonium bicarbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium bicarbonate, sodium carbonate, and the like. Specific examples of the amine include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylene Diamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, imidazole or triazole, etc. azoles, etc. Specific examples of the quaternary phosphonium compound include quaternary phosphonium hydroxide such as tetramethylphosphonium hydroxide and tetraethylphosphonium hydroxide.

As a quaternary ammonium compound, quaternary ammonium salts (typically strong bases) such as tetraalkylammonium salts and hydroxyalkyltrialkylammonium salts can be used. The anion component in this quaternary ammonium salt can be, for example, OH ⁻ , F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , BH ₄ ⁻ and the like. As an example of the said quaternary ammonium compound, the quaternary ammonium salt whose anion is OH ^- , ie, quaternary ammonium hydroxide, can be mentioned. Specific examples of quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexyl hydroxide Tetraalkylammonium hydroxide such as ammonium hydroxide; Hydroxyalkyltrialkylammonium hydroxide such as 2-hydroxyethyltrimethylammonium hydroxide (also known as choline) and the like.

Among these basic compounds, for example, at least one basic compound selected from the group consisting of alkali metal hydroxides, quaternary ammonium hydroxide and ammonia is suitably used. In particular, tetraalkylammonium hydroxide (such as tetramethylammonium hydroxide) and ammonia are preferred, and ammonia is particularly preferred.

The content of the basic compound in the polishing composition is not particularly limited. From the viewpoint of improving the polishing rate, etc., the content is usually set to 0.0005 wt % or more, preferably 0.001 wt % or more, and more preferably 0.003 wt % or more. In addition, from the viewpoint of improving surface quality (for example, reducing haze), the above-mentioned content is appropriately set to less than 0.1% by weight, preferably less than 0.05% by weight, and less than 0.03% by weight ( For example, less than 0.025% by weight, even less than 0.01% by weight) is preferred. In addition, when two or more types are used in combination, the said content means the total content of two or more types of basic compounds. These contents are suitably used, for example, in the polishing liquid (working slurry) supplied to the substrate.

The polishing composition disclosed here preferably contains the surfactant A and the basic compound in an appropriate ratio, but is not particularly limited. In this way, the chemical polishing action by the basic compound can be well exerted, and at the same time, the maintenance or improvement of the surface quality of the polished surface can be appropriately achieved. The ratio of the content C _B of the basic compound to the content C _A of the surfactant A (C _B /C _A ) is, for example, 0.01 or more, and preferably 0.1 or more from the viewpoint of exerting the effect of adding the basic compound, It is preferably 0.3 or more, more preferably 0.8 or more, and may be 1 or more or 3 or more. In addition, the above-mentioned ratio (C _B /C _A ) can be set to 100 or less, and from the viewpoint of better exhibiting the effect of adding the surfactant A, it is preferably 30 or less, more preferably 10 or less, and may be, for example, 5 or less or less than 2.

＜Water＞ As the water contained in the polishing composition disclosed here, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, and the like are suitably used. In order to avoid inhibiting the functions of other components contained in the polishing composition as much as possible, the total content of, for example, transition metal ions in the water used is preferably 100 ppb or less. The purity of water can be improved by operations such as removal of impurity ions using an ion exchange resin, removal of foreign substances using a filter, distillation, and the like. In addition, the polishing composition disclosed here may further contain an organic solvent (lower alcohol, lower ketone, etc.) that can be uniformly mixed with water as necessary. The solvent contained in the polishing composition is preferably 90% by volume or more of water, and preferably 95% or more by volume (eg, 99 to 100% by volume) of water.

＜Abrasive Grain＞ The abrasive compositions disclosed herein may or may not contain abrasive particles. In several suitable aspects, the abrasive composition comprises abrasive particles. The abrasive grains have the function of mechanically polishing the surface of the substrate. The polishing composition contains abrasive grains, and the polishing rate can be increased by the mechanical polishing action of the contained abrasive grains. The material and properties of the abrasive grains are not particularly limited, and can be appropriately selected according to the purpose of use of the polishing composition, the state of use, and the like. Examples of abrasive particles include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles include silica particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, iron oxide particles, and the like. Oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; carbonates such as calcium carbonate or barium carbonate, etc. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles, poly(meth)acrylic acid particles (here, (meth)acrylic acid means acrylic acid and methacrylic acid in general), and polyacrylonitrile particles. Wait. Such abrasive grains may be used alone or in combination of two or more.

The above-mentioned abrasive particles are preferably inorganic particles, especially particles formed of metal or semi-metal oxides, and silicon dioxide particles are particularly preferred. In a polishing composition that can be used for polishing a substrate (for example, finish polishing) having a surface formed of silicon, such as a silicon wafer described later, it is particularly meaningful to use silica particles as abrasive grains. The technique disclosed here is suitable to be implemented, for example, in a form in which the above-mentioned abrasive grains are substantially formed of silica particles. Here, "substantially" means that 95% by weight or more (preferably 98% by weight or more, preferably 99% by weight or more, or 100% by weight) of the particles constituting the abrasive grains are silica particles.

Specific examples of the silica particles include colloidal silica, fumed silica, precipitated silica, and the like. The silica particles may be used alone or in combination of two or more. From the viewpoint of easily obtaining a polished surface with excellent surface quality after polishing, it is particularly preferable to use colloidal silica. The colloidal silica is suitable, for example, by the ion exchange method, using water glass (sodium silicate) as the raw material to produce colloidal silica, or alkoxylation colloidal silica (by alkane colloidal silica produced by the hydrolysis condensation reaction of oxysilane). The colloidal silica may be used alone or in combination of two or more.

The true specific gravity of the abrasive grain constituent material (for example, silicon dioxide constituting the silicon dioxide particles) is preferably 1.5 or more, preferably 1.6 or more, and more preferably 1.7 or more. The upper limit of the true specific gravity of silica is not particularly limited, and is typically 2.3 or less, preferably 2.2 or less, more preferably 2.0 or less, for example, 1.9 or less. The true specific gravity of abrasive grains (eg, silica particles) can be measured by a liquid replacement method using ethanol as a replacement liquid.

The average primary particle size of the abrasive grains (typically, silica particles) is not particularly limited, but is preferably 5 nm or more, preferably 10 nm or more, from the viewpoint of the polishing rate and the like. The average primary particle size is preferably 15 nm or more, and preferably 20 nm or more (eg, more than 20 nm), from the viewpoint of obtaining a high polishing effect (eg, haze reduction, defect removal, etc.). In addition, from the viewpoint of preventing scratches and the like, the average primary particle diameter of the abrasive grains is preferably 100 nm or less, preferably 50 nm or less, and more preferably 45 nm or less. From the viewpoint of easily obtaining a lower haze surface, the average primary particle size of the abrasive particles may be 43 nm or less, or less than 40 nm, less than 38 nm, less than 35 nm, less than 32 nm, less than 30nm.

In addition, in this specification, the average primary particle size refers to the specific surface area (BET value) measured by the BET method, and the average primary particle size (nm)=6000/(true density (g/cm ^{3 )} )×BET value (m ² /g)) calculated particle size (BET particle size). The above-mentioned specific surface area can be measured using, for example, a surface area measuring apparatus manufactured by Micromeritics, Inc., trade name "Flow Sorb II 2300".

The average secondary particle size of the abrasive grains (eg, silica particles) is not particularly limited, and can be appropriately selected, for example, from a range of about 15 nm to 300 nm. From the viewpoint of improving the polishing rate, the average secondary particle size is preferably 30 nm or more, more preferably 35 nm or more. In several aspects, the above-mentioned average secondary particle diameter may be, for example, 40 nm or more or 42 nm or more, preferably 44 nm or more. In addition, the average secondary particle diameter is usually preferably 250 nm or less, preferably 200 nm or less, and more preferably 150 nm or less. In several suitable aspects, the above-mentioned average secondary particle size is 120 nm or less, preferably 100 nm or less, more preferably 70 nm or less, for example, 60 nm or less or 50 nm or less.

In addition, in this specification, an average secondary particle diameter means the particle diameter (volume average particle diameter) measured by the dynamic light scattering method. The average secondary particle diameter of the abrasive grains can be measured, for example, by the dynamic light scattering method using "Nanotrac (registered trademark) UPA-UT151" manufactured by Nikkiso Co., Ltd.

The shape (shape) of the abrasive particles may be spherical or non-spherical. Specific examples of non-spherical particles include peanut shape (that is, the shape of peanut shells), cocoon shape, jumbo shape, rugby ball shape, and the like. Suitable for example are abrasive grains in which most of the particles are peanut-like or cocoon-like.

The average value (average aspect ratio) of the long diameter/short diameter ratio of the abrasive grains is 1.0 or more in principle, preferably 1.05 or more, and more preferably 1.1 or more, but is not particularly limited. Higher grinding rates can be achieved as the average aspect ratio increases. In addition, the average aspect ratio of the abrasive grains is preferably 3.0 or less, more preferably 2.0 or less, and more preferably 1.5 or less, from the viewpoint of reducing scratches and the like.

The shape (outline) or the average aspect ratio of the abrasive grains can be obtained, for example, by observation with an electron microscope. The specific step of obtaining the average aspect ratio, for example, using a scanning electron microscope (SEM), for a predetermined number (for example, 200) of the abrasive particles that can be identified as independent particles, the smallest particle circumscribed to the image of each particle is drawn. rectangle. Then, a value obtained by dividing the length of the long side (the value of the long axis) by the length of the short side (the value of the short axis) for the rectangle drawn on the image of each particle is calculated as the ratio of the long axis to the short diameter (aspect ratio). ). The average aspect ratio can be obtained by arithmetically averaging the aspect ratios of the predetermined number of particles.

When the polishing composition contains abrasive grains, the content of the abrasive grains in the polishing composition is not particularly limited. More preferably, it is 0.15 weight% or more. Higher grinding rates can be achieved with increasing abrasive grain content. The above-mentioned content is suitably 10% by weight or less, preferably 7% by weight or less, preferably 5% by weight or less, more preferably 2% by weight or less, for example, 1% by weight or less, or 0.5% by weight or less, or 0.4% by weight or less . Thereby a higher quality surface can be achieved. The content of the above-mentioned abrasive grains is suitably used in the aspect in which the polishing composition is used in the form of a polishing liquid (working slurry).

＜Water-soluble polymer＞ The polishing composition disclosed herein may contain a water-soluble polymer. The water-soluble polymer helps to protect the surface of the substrate or improve the wettability of the surface of the substrate after polishing. For example, by selecting and using the surfactant A and an appropriate water-soluble polymer, the surface quality and the polishing rate after polishing can be better balanced. Among several aspects, the water-soluble polymer may include a hydroxyl group, a carboxyl group, an acyloxy group, a sulfonic acid group, an amide structure, an imide structure, a quaternary ammonium structure, a heterocyclic structure, a vinyl group in the molecule. Compounds of structure etc. As the water-soluble polymer, for example, a cellulose derivative, a starch derivative, a polymer containing an oxyalkylene unit, a polyvinyl alcohol-based polymer, a polymer containing a nitrogen atom, or the like can be used, and one of the polymers containing a nitrogen atom can be used. In one aspect, N-vinyl type polymers, N-(meth)acryloyl type polymers, and the like can be used. The water-soluble polymer may be a polymer derived from a natural product or a synthetic polymer. The water-soluble polymer may be used alone or in combination of two or more.

In several aspects, polymers derived from natural products can be used as water-soluble macromolecules. Examples of polymers derived from natural products include cellulose derivatives and starch derivatives. The polymers derived from natural products may be used alone or in combination of two or more.

In several aspects, cellulose derivatives can be used as water-soluble polymers. Here, the cellulose derivative is a polymer containing a beta glucose unit as a main repeating unit. Specific examples of cellulose derivatives include hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and ethyl cellulose. , ethyl hydroxyethyl cellulose, carboxymethyl cellulose, etc. In particular, HEC is preferred. The cellulose derivatives may be used alone or in combination of two or more.

In several other aspects, starch derivatives can be used as water-soluble polymers. The starch derivative is a polymer containing an α-glucose unit as a main repeating unit, and examples thereof include α-starch, pullulan, carboxymethyl starch, cyclodextrin, and the like. The starch derivatives may be used alone or in combination of two or more.

In several other aspects, synthetic polymers can be used as water-soluble macromolecules. The effect by the technique disclosed here can be suitably exhibited in the aspect in which a synthetic polymer is used for the water-soluble polymer. The synthetic polymers may be used alone or in combination of two or more.

In several aspects, the water-soluble polymer may use a polymer containing oxyalkylene units. Examples of polymers containing oxyalkylene units include polyethylene oxide (PEO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), EO Random copolymers with PO or BO, etc. Among them, block copolymers of EO and PO or random copolymers of EO and PO are preferred. The block copolymer of EO and PO may be a diblock copolymer or a triblock copolymer including a PEO block and a polypropylene oxide (PPO) block. Examples of the above triblock copolymers include PEO-PPO-PEO type triblock copolymers and PPO-PEO-PPO type triblock copolymers. Usually PEO-PPO-PEO type triblock copolymer is preferred.

In addition, in this specification, unless otherwise stated, a copolymer means various copolymers, such as a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, etc. in general.

Among the block copolymers or random copolymers of EO and PO, the molar ratio (EO/PO) of EO and PO constituting the copolymer is, from the viewpoints of solubility in water and detergency, etc. It is preferably more than 1, more preferably 2 or more, and more preferably 3 or more (for example, 5 or more).

In several suitable aspects, a polyvinyl alcohol-based polymer can be used as the water-soluble polymer. When the composition of the polyvinyl alcohol-based polymer is included, the polishing rate can be easily improved while maintaining the surface quality after polishing. The polyvinyl alcohol-based polymer refers to a polymer including a vinyl alcohol unit (hereinafter also referred to as "VA unit") as its repeating unit. The polyvinyl alcohol-based polymer may contain only VA units as repeating units, or may contain VA units and repeating units other than VA units (hereinafter also referred to as "non-VA units"). The polyvinyl alcohol-based polymer may be a random copolymer including a VA unit and a non-VA unit, or may be a block copolymer, an alternating 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 above-mentioned polyvinyl alcohol-based polymer may be unmodified polyvinyl alcohol (non-modified PVA) or may be modified polyvinyl alcohol (modified PVA). Here, non-modified PVA means substantially no repeating units (—CH ₂ —CH(OCOCH ₃ ) that are produced by hydrolysis (saponification) of polyvinyl acetate and vinyl acetate undergoes vinyl polymerization. )-) and a polyvinyl alcohol-based polymer of repeating units other than VA units. The degree of saponification of the non-modified PVA may be, for example, 60% or more, and may be 70% or more, or 80% or more, or 90% or more from the viewpoint of water solubility.

The polyvinyl alcohol-based polymer may include a VA unit and a group selected from the group consisting of oxyalkylene group, carboxyl group, sulfonic acid group, amine group, hydroxyl group, amide group, imide group, nitrile group, ether group, ester group and A modified PVA of a non-VA unit of at least one configuration of its salt. In addition, the non-VA unit that can be contained in the modified PVA may be, for example, a repeating unit derived from an N-vinyl type monomer or an N-(meth)acryloyl type monomer described later, a repeating unit derived from ethylene, a repeating unit derived from Repeating units of alkyl vinyl ethers, repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, and the like are not limited thereto. A suitable example of the said N-vinyl type monomer is N-vinylpyrrolidone. A suitable example of the said N-(meth)acryloyl-type monomer is N-(meth)acryloylmorpholine. The above-mentioned alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, and 2-ethylhexyl vinyl ether. The vinyl ester of the above-mentioned monocarboxylic acid having 3 or more carbon atoms may be, for example, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl hexanoate and other monocarboxylic acids having 3 to 7 carbon atoms. vinyl ester. In addition, the polyvinyl alcohol-based polymer may be an acetalized polyvinyl alcohol-based polymer. The acetalized polyvinyl alcohol-based polymer includes, for example, modified PVA obtained by acetalizing a part of the VA unit contained in the polyvinyl alcohol-based polymer with aldehyde. As the above-mentioned aldehydes, for example, alkyl aldehydes are preferably used, and alkyl aldehydes having an alkyl group having 1 to 7 carbon atoms are preferred, and acetaldehyde, n-propionaldehyde, n-butyraldehyde, and n-valeraldehyde are particularly preferred. As the polyvinyl alcohol-based polymer, cationically modified polyvinyl alcohol into which a cationic group such as a quaternary ammonium structure has been introduced may also be used. The above-mentioned cationically modified polyvinyl alcohols include, for example, those containing diallyldialkylammonium salts, N-(meth)acryloaminoalkyl-N,N,N-trialkylammonium salts and the like. The monomer of the cationic group introduces the polyvinyl alcohol of the cationic group.

The ratio of the molar number of the VA unit to the total molar number of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. In several aspects, the molar ratio of the above VA units may be above 50% or above 65%, above 75%, above 80%, above 90% (eg above 95% or above 98%), however There is no particular limitation. Substantially 100% of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100%" means that the polyvinyl alcohol-based polymer does not contain non-VA units intentionally at least, and typically the molar number of non-VA units is equal to the total molar number of all repeating units. The proportion is less than 2% (for example, less than 1%), including 0%. In other aspects, the ratio of the molar number of the VA unit to the total molar number of all repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less. % or less, 70% or less.

The VA unit content (content on a weight basis) in the polyvinyl alcohol-based polymer may be, for example, 5% by weight or more, or 10% by weight or more, 20% by weight or more, or 30% by weight or more. In several aspects, the above-mentioned VA unit content may be 50 wt% or more (eg, more than 50 wt%) or 70 wt% or more, 80 wt% or more (eg, 90 wt% or more or 95 wt% or more, 98 wt%) above), however, it is not particularly limited. Substantially 100% by weight of the repeating units constituting the polyvinyl alcohol-based polymer may be VA units. Here, "substantially 100% by weight" means that at least non-VA units are not intentionally contained as repeating units constituting the polyvinyl alcohol-based polymer, and typically means that the content of non-VA units in the polyvinyl alcohol-based polymer is not Up to 2 wt% (eg less than 1 wt%). In other aspects, the content of VA units in the polyvinyl alcohol-based polymer may be, for example, 95% by weight or less, or 90% by weight or less, 80% by weight or less, or 70% by weight or less.

The polyvinyl alcohol-based polymer may contain a plurality of polymer chains with different VA unit contents in the same molecule. Here, the polymer chain refers to a part (fragment) constituting a part of a polymer molecule. For example, a polyvinyl alcohol-based polymer can also contain a polymer chain with a VA unit content of more than 50 wt % in the same molecule, and the VA unit content is less than 50 wt % (that is, the non-VA unit content is higher than 50 wt %). the polymer chain B.

The polymer chain A may contain only VA units as repeating units, or may contain VA units as well as non-VA units. The VA unit content in the polymer chain A may be 60% by weight or more, or 70% by weight or more, 80% by weight or more, or 90% by weight or more. In several aspects, the content of VA units in the polymer chain A may be 95 wt% or more or 98 wt% or more. Substantially 100% by weight 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 non-VA units as well as VA units. The non-VA unit content in the polymer chain B may be 60% by weight or more, or 70% by weight or more, 80% by weight or more, or 90% by weight or more. In several aspects, the content of non-VA units in polymer chain B may be greater than 95% by weight or greater than 98% by weight. Substantially 100% by weight of the repeating units constituting the polymer chain B may be non-VA units.

Examples of the polyvinyl alcohol-based polymer including the polymer chain A and the polymer chain B in the same molecule include block copolymers and graft copolymers including these polymer chains. The above-mentioned graft copolymer may be a graft copolymer in which polymer chain B (side chain) is grafted on polymer chain A (main chain), or may be grafted on polymer chain B (main chain). The graft copolymer of the structure of the branched polymer chain A (side chain). In one aspect, a polyvinyl alcohol-based polymer having a structure in which polymer chain A is grafted with polymer chain B can be used.

Examples of the polymer chain B include a polymer chain having a repeating unit derived from an N-vinyl type monomer as a main repeating unit, and a polymer chain mainly repeating a repeating unit derived from an N-(meth)acryloyl type monomer. A polymer chain of units, a polymer chain with an oxyalkylene unit as the main repeating unit, and the like. In addition, in this specification, the main repeating unit means the repeating unit contained in more than 50 weight%, unless it mentions in particular.

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

In this specification, examples of N-vinyl type monomers include monomers having nitrogen-containing heterocycles (eg, lactamide rings) and N-vinyl chain amides. Specific examples of N-vinyllactam-type monomers include N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, and N-vinyl base-1,3-oxazin-2-one, N-vinyl-3,5-morpholindione, etc. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionamide, N-vinylbutyricamide, and the like. The polymer chain B may be, for example, an N-vinyl-based polymer chain whose repeating units exceed 50 wt % (eg, 70 wt % or more or 85 wt % or more, 95 wt % or more) as N-vinylpyrrolidone units. Substantially all of the repeating units constituting the polymer chain B may be N-vinylpyrrolidone units.

Other examples of the polymer chain B include a polymer chain having a repeating unit derived from an N-(meth)acryloyl-based monomer as a main repeating unit, that is, N-(meth)acryloyl-based polymerization. chain of things. The content of repeating units derived from N-(meth)acryloyl-based monomers in the N-(meth)acryloyl-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more or 85% by weight % or more and 95% by weight or more. Substantially all of the polymer chain B may be repeating units derived from N-(meth)acryloyl-based monomers.

In this specification, examples of N-(meth)acryloyl-type monomers include chain amides having N-(meth)acryloyl groups and N-(meth)acryloyl groups. Cyclic amides. Examples of chain amides having an N-(meth)acrylamide group include (meth)acrylamide; N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide N-Alkyl(meth)propene such as amine, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-n-butyl(meth)acrylamide, etc. Acrylamide; N,N-Dimethyl(meth)acrylamide, N,N-Diethyl(meth)acrylamide, N,N-Dipropyl(meth)acrylamide, N,N-Diethyl(meth)acrylamide N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, etc., N,N-dialkyl(meth)acrylamide, and the like. Examples of the cyclic amide having an N-(meth)acryloyl group include N-(meth)acrylomorpholine, N-(meth)acrylopyrrolidine, and the like.

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

As an example of an oxyalkylene unit, an oxyethylene unit, an oxypropylene unit, an oxybutylene unit, etc. are mentioned. Such oxyalkylene units may be repeating units derived from the corresponding respective alkylene oxides. The oxyalkylene units contained in the oxyalkylene-based polymer chain may be one type or two or more types. For example, it may be an oxyalkylene-based polymer chain comprising a combination of oxyethylene units and oxypropylidene units. In an oxyalkylene-based polymer chain containing two or more oxyalkylene units, these oxyalkylene units may be random copolymers, block copolymers, and alternating copolymers of corresponding alkylene oxides or graft copolymers.

Further examples of the polymer chain B include a polymer chain containing repeating units derived from an alkyl vinyl ether (eg vinyl ether having an alkyl group having 1 to 10 carbon atoms), a polymer chain derived from a monocarboxylic acid Polymer chains of repeating units of vinyl esters (eg, vinyl esters of monocarboxylic acids having 3 or more carbon atoms), polymer chains into which cationic groups (eg, cationic groups having a quaternary ammonium structure) are introduced, and the like.

In the technique disclosed here, as the polyvinyl alcohol-based polymer of the water-soluble polymer, a modified polyvinyl alcohol containing a copolymer of a VA unit and a non-VA unit is preferable. In addition, the degree of saponification of the polyvinyl alcohol-based polymer as a water-soluble polymer is usually 50 mol% or more, preferably 65 mol% or more, preferably 70 mol% or more, for example, 75 mol% or more. Moreover, the saponification degree of a polyvinyl alcohol-type polymer is 100 mol% or less in principle.

Among other aspects, N-vinyl type polymers can be used as water-soluble polymers. Examples of N-vinyl-type polymers include polymers containing repeating units derived from monomers having nitrogen-containing heterocycles (eg, lactamide rings). Examples of such polymers include homopolymers and copolymers of N-vinyllactam-type monomers (for example, copolymers in which the copolymerization ratio of N-vinyllactam-type monomers exceeds 50% by weight) ), homopolymers and copolymers of N-vinyl chain amide (for example, a copolymer in which the copolymerization ratio of N-vinyl chain amide exceeds 50% by weight), and the like.

Specific examples of N-vinyllactam-type monomers (that is, compounds having a lactamide structure and an N-vinyl group in one molecule) include N-vinylpyrrolidone (VP), N-vinylpiperidine Ketone, N-vinylmorpholinone, N-vinylcaprolactam (VC), N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinodi Ketones etc. Specific examples of polymers containing N-vinyllactam-type monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, and one or both of VP and VC. Random copolymers with other vinyl monomers (such as acrylic monomers, vinyl ester monomers, etc.), block copolymers containing polymer chains containing one or both of VP and VC, alternating copolymers or graft copolymers, etc. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionamide, N-vinylbutyricamide, and the like.

Among other aspects, N-(meth)acryloyl-based polymers are suitably used as water-soluble polymers. The effect produced by the technique disclosed here can be more suitably achieved by a composition containing an N-(meth)acryloyl-based polymer. Examples of N-(meth)acryloyl-based polymers include homopolymers and copolymers of N-(meth)acryloyl-based monomers (typically N-(meth)acryloyl) The copolymerization ratio of the base monomer exceeds 50% by weight of the copolymer). Examples of N-(meth)acryloyl-based monomers include chain amides having N-(meth)acryloyl groups and cyclic amides having N-(meth)acryloyl groups.

Examples of chain amides having an N-(meth)acrylamide group include (meth)acrylamide; N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide N-Alkyl(meth)propene such as amine, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-n-butyl(meth)acrylamide, etc. Acrylamide; N,N-Dimethyl(meth)acrylamide, N,N-Diethyl(meth)acrylamide, N,N-Dipropyl(meth)acrylamide, N,N-Diethyl(meth)acrylamide N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, etc., N,N-dialkyl(meth)acrylamide, and the like. Examples of polymers containing a chain amide having an N-(meth)acrylamide group as a monomer unit include homopolymers of N-isopropylacrylamide and N-isopropylacrylamide (for example, a copolymer with a copolymerization ratio of N-isopropylacrylamide exceeding 50% by weight).

Examples of cyclic amides having an N-(meth)acryloyl group include N-acrylomorpholine, N-acrylothiomorpholine, N-acrylopiperidine, and N-acryloyl pyrrolidine, N-methacryloylmorpholine, N-methacryloylpiperidine, N-methacryloylpyrrolidine, etc. An example of a polymer containing a cyclic amide having an N-(meth)acryloyl group as a monomer unit includes acryl morpholine-based polymer (PACMO). Typical examples of acrylomorpholine polymers include homopolymers of N-acrylomorpholine (ACMO) and copolymers of ACMO (for example, copolymers in which the copolymerization ratio of ACMO exceeds 50% by weight). In acryl morpholine-based polymers, the ratio of the molar number of ACMO units to the total molar number of all repeating units is usually 50% or more, and 80% or more (for example, 90% or more, typically 95% or more) is appropriate. All of the repeating units of the water-soluble polymer may be substantially composed of ACMO units.

The technique disclosed herein can be used in combination with one or two or more of a nitrogen atom-containing polymer (typically N-(meth)acryloyl type polymer) and a nitrogen atom-containing polymer (typically water-soluble polymers (non-nitrogen-containing polymers, typically non-N-(meth)acryloyl-based polymers) One or two or more kinds of water-soluble polymers are appropriately implemented as aspects, but are not particularly limited. By using two or more of the above-mentioned water-soluble polymers in combination, it is possible to achieve both surface quality and polishing rate at a high level. The polymer not containing a nitrogen atom (typically, a non-N-(meth)acryloyl-based polymer) is not particularly limited, and, for example, a modified or non-modified polyvinyl alcohol-based polymer is suitably used. The non-nitrogen-containing polymer (typically, N-(meth)acryloyl-based polymer) used in combination with the above-mentioned polyvinyl alcohol-based polymer is not particularly limited, as long as it contains an N-(methyl) A polymer of acrylamide-based cyclic amide as a monomer unit is preferable, and PACMO is preferable. In the aspect in which a nitrogen atom-containing polymer and a nitrogen atom-containing polymer are used together, the usage ratio (nitrogen atom-containing polymer: nitrogen atom-containing polymer) is not particularly limited, and it is based on weight. The meter can be set as 1:9~9:1, or 3:7~8:2, 5:5~7:3.

In the technique disclosed here, the weight average molecular weight (Mw) of the water-soluble polymer is not particularly limited. The Mw of the water-soluble polymer may be, for example, about 200×10 ⁴ or less, preferably about 150×10 ⁴ or less, and preferably about 100×10 ⁴ or less, or about 50, from the viewpoint of washability and the like. ×10 ⁴ or less. In addition, from the viewpoint of the protective properties of the polished surface, the Mw of the water-soluble polymer may be, for example, 0.2×10 ⁴ or more, preferably 0.5×10 ⁴ or more. In several aspects, the above-mentioned Mw is suitably 1.0×10 ⁴ or more, and may be 2×10 ⁴ or more, for example, 5×10 ⁴ or more.

In the technique disclosed here, the molecular weight range of a suitable water-soluble polymer compound differs depending on the type of polymer used. For example, the Mw of the cellulose derivative and the starch derivative can be set to approximately 200×10 ⁴ or less, respectively, and preferably 150×10 ⁴ or less. The above-mentioned Mw may be about 100×10 ⁴ or less or about 50×10 ⁴ or less (eg, about 30×10 ⁴ or less). In addition, from the viewpoint of the protective properties of the polished surface, the Mw is, for example, about 0.2×10 ⁴ or more, preferably about 0.5×10 ⁴ or more, preferably about 1.0×10 ⁴ or more, preferably about 3.0×10 ⁴ or more, more preferably about 10×10 ⁴ or more, or may be about 20×10 ⁴ or more.

In addition, for example, the Mw of the polyvinyl alcohol-based polymer can be set to be 100×10 ⁴ or less, and preferably 60×10 ⁴ or less. From the viewpoint of concentration efficiency and the like, the Mw may be 30×10 ⁴ or less, preferably 20×10 ⁴ or less, for example, 10×10 ⁴ or less, typically 8×10 ⁴ or less, or 5×10 ⁴ or less and 3×10 ⁴ or less. In addition, from the viewpoint of being suitable for protecting the polished surface and maintaining or improving the surface quality, Mw may be, for example, 0.2×10 ⁴ or more, and usually 0.5×10 ⁴ or more is preferable. In several aspects, Mw is suitable to be 0.8×10 ⁴ or more, preferably 1.0×10 ⁴ or more, or can be 2×10 ⁴ or more, 3×10 ⁴ or more, such as 4×10 ⁴ or more or 5× 10 ⁴ or more.

In addition, for example, the Mw of a polymer containing a nitrogen atom (for example, an N-(meth)acryloyl-based polymer, preferably PACMO) can be set to 100×10 ⁴ or less, preferably 70×10 ⁴ or less. From the viewpoint of concentration efficiency and the like, the above-mentioned Mw may be 60×10 ⁴ or less or 50×10 ⁴ or less. In addition, from the viewpoint of maintaining or improving surface quality, Mw may be, for example, 1.0×10 ⁴ or more or 10×10 ⁴ or more. Among several aspects, Mw is suitably 20×10 ⁴ or more, preferably 30×10 ⁴ or more, for example, 40×10 ⁴ or more.

As the Mw of the water-soluble polymer, the molecular weight calculated from the value obtained by water-based gel permeation chromatography (GPC) (water-based, polyethylene oxide conversion) can be used. For the GPC measurement device, the model name "HLC-8320GPC" manufactured by Tosoh Corporation can be used. The measurement can be performed under the following conditions, for example. The same method can also be used in the embodiments to be described later. [GPC measurement conditions] Sample concentration: 0.1 wt% Column: TSKgel GMPWXL Detector: Differential Refractometer Elution solution: 100mM sodium nitrate aqueous solution/acetonitrile=10~8/0~2 Flow rate: 1mL/min Measurement temperature: 40℃ Sample injection volume: 200 μL

From the viewpoints of reducing aggregates, improving cleaning properties, and the like, the water-soluble polymer is preferably a nonionic polymer. In addition, synthetic polymers are suitably used as water-soluble polymers from the viewpoint of ease of control of chemical structure and purity. For example, when the technique disclosed here is implemented in the form of including a synthetic polymer as the water-soluble polymer, the polishing composition can substantially not use a polymer derived from a natural product as the water-soluble polymer. Here, "substantially not used" means that the amount of the natural product-derived polymer used is 100 parts by weight, typically 3 parts by weight or less, preferably 1 part by weight or less, including 0 parts by weight relative to the total content of the water-soluble polymer. copies or below the detection limit.

The content (content based on weight) of the water-soluble polymer in the polishing composition is not particularly limited. For example, it can be set at 1.0×10 ⁻⁴ wt % or more. From the viewpoint of reducing haze and the like, a suitable content is 5.0×10 ^-4 wt % or more, preferably 1.0×10 ^-3 wt % or more, more preferably 2.0×10 ^-3 wt % or more, for example, 5.0× 10 ^-3 wt% or more. In addition, from the viewpoint of the polishing rate, etc., the content is preferably 0.2 wt % or less, more preferably 0.1 wt % or less, and 0.05 wt % or less (for example, 0.02 wt % or less, or even 0.015 wt % or less) better. In addition, when the said polishing composition contains two or more water-soluble polymers, the said content means the total content (weight basis content) of all the water-soluble polymers contained in the said polishing composition. These contents are suitably used, for example, in the polishing liquid (working slurry) supplied to the substrate.

In addition, in the case where the polishing composition disclosed herein contains abrasive grains, the content of the water-soluble polymer (the total amount in the case of including two or more water-soluble polymers) can also be determined from the relative relationship with the abrasive grains. to stipulate. In several aspects, the content of the water-soluble polymer relative to 100 parts by weight of the abrasive grains may be, for example, 0.01 part by weight or more, and it is appropriate to set it at 0.1 part by weight or more from the viewpoint of reducing haze, etc. , is preferably 0.5 parts by weight or more, preferably 1 part by weight or more, more preferably 3 parts by weight or more, for example, 4 parts by weight or more, but is not particularly limited. In addition, the content of the water-soluble polymer with respect to 100 parts by weight of the abrasive grains may be, for example, 50 parts by weight or less or 30 parts by weight or less. From the viewpoint of the dispersion stability of the polishing composition, etc., in several aspects, the content of the water-soluble polymer relative to 100 parts by weight of the abrasive particles is appropriately set at 15 parts by weight or less, preferably 10 parts by weight part or less, or it can be set at less than 8 parts by weight and less than 7 parts by weight.

(Any Surfactant B) In addition to the surfactant A, the polishing composition disclosed here may further contain a surfactant B (optional surfactant) different from the surfactant A as necessary. As the surfactant B, any of anionic, cationic, nonionic, and amphoteric may be used. Usually, anionic or nonionic surfactant B is suitably used. From the viewpoint of low foaming properties and ease of pH adjustment, nonionic surfactants are preferred. For example, oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc.; polyoxyethylene alkylene ether, polyoxyethylene alkyl phenylene ether, polyoxyethylene Polyoxyalkylene derivatives of alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glycol ether fatty acid esters, polyoxyethylene sorbitan fatty acid esters, etc. base adduct); a variety of oxyalkylene copolymers (such as diblock copolymers, triblock copolymers, random copolymers, alternating copolymers) and other non-ionic surfactants. For example, as the above-mentioned surfactant B, a surfactant containing a polyoxyalkylene structure can be used. The surfactant B may be used alone or in combination of two or more.

Specific examples of the nonionic surfactant containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide) Ethylene oxide)-PPO (polypropylene oxide)-PEO type triblock, PPO-PEO-PPO type triblock copolymer, etc.), random copolymers of EO and PO, polyoxyethylene glycol, polyethylene Oxyethylidene propyl ether, polyoxyethylidene butyl ether, polyoxyethylidene amyl ether, polyoxyethylidene hexyl ether, polyoxyethylidene octyl ether, polyoxyethylidene-2- Ethylhexyl ether, polyoxyethylidene nonyl ether, polyoxyethylidene decyl ether, polyoxyethylidene isodecyl ether, polyoxyethylidene tridecyl ether, polyoxyethylidene lauryl ether Ether, polyoxyethylidene cetyl ether, polyoxyethylidene stearyl ether, polyoxyethylidene isostearyl ether, polyoxyethylidene oleyl ether, polyoxyethylene phenylene ether , polyoxyethylene octyl phenylene ether, polyoxyethylene ethylidene nonyl phenyl ether, polyoxyethylene ethylidene dodecyl phenyl ether, polyoxyethylene ethylidene styrenated phenylene ether, polyoxyethylidene lauryl base amine, polyoxyethylidene stearylamine, polyoxyethylidene oleylamine, polyoxyethylidene monolaurate, polyoxyethylidene monostearate, polyoxyethylidene dihard Fatty acid ester, polyoxyethylene monooleate, polyoxyethylene dioleate, monolauric acid polyoxyethylene sorbitan, monopalmitate polyoxyethylene sorbitan, Polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitol tetraoleate , Polyoxyethylene castor oil, polyoxyethylene hardened castor oil, etc.

The weight-average molecular weight (Mws) of the surfactant B is typically less than 2,000, and is preferably 1,900 or less (eg, less than 1,800) from the viewpoint of filterability, cleanability, and the like. In addition, Mws of the surfactant is usually 200 or more suitable from the viewpoint of interfacial activation ability and the like, and preferably 250 or more (eg, 300 or more) from the viewpoint of haze reduction effect and the like. The preferable range of Mws of the surfactant B varies depending on the type of the surfactant B. For example, in the case where polyoxyethylene alkylene ether is used as the surfactant B, its Mws is preferably 1500 or less, or may be 1000 or less (for example, 500 or less). In addition, for example, when a PEO-PPO-PEO type triblock copolymer is used as the surfactant B, its Mws may be, for example, 500 or more, 1000 or more, or even 1200 or more. As for the molecular weight of the surfactant B, similarly to the surfactant A, the molecular weight calculated from the chemical formula can be used.

When the polishing composition disclosed herein contains surfactant B in addition to surfactant A, the content of surfactant B is set to be 3 times or less (for example, 0.01 times or more) of the content of surfactant A. 3 times or less) is appropriate, and the content of the surfactant A may be, for example, 1 time or less, 0.3 times or less, or 0.1 times or less. The technique disclosed here is suitably implemented in the aspect which does not contain surfactant B substantially in the polishing composition. In addition, the polishing composition does not substantially contain the surfactant B, which means that the surfactant B is at least not intentionally contained.

＜Other ingredients＞ The polishing composition disclosed here may further contain, for example, an organic acid, an organic acid salt, an inorganic acid, an inorganic acid salt, a chelating agent, a preservative, and an antifungal agent, as necessary, within the range that does not significantly impair the effects of the present invention. Such well-known additives that can be used in polishing compositions such as those used in the finishing polishing step of silicon wafers.

An organic acid and its salt and an inorganic acid and its salt can be used individually by 1 type or in combination of 2 or more types. 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, itonic acid, citric acid, oxalic acid, tartaric acid, malic acid, maleic acid, rich Organic sulfonic acids such as maleic acid, succinic acid, glycolic acid, malonic acid, gluconic acid, alanine, glycine, lactic acid, hydroxyethylene diphosphoric acid (HEDP), methanesulfonic acid, etc. phosphonophosphoric acid) (NTMP), phosphonobutane tricarboxylic acid (PBTC) and the like. Examples of organic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of organic acids. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, sulfuric acid, phosphonic acid, nitric acid, hypophosphorous acid, boric acid, carbonic acid, and the like. Examples of inorganic acid salts include alkali metal salts (sodium salts, potassium salts, etc.) and ammonium salts of inorganic acids.

The above-mentioned chelating agents may be used alone or in combination of two or more. Examples of the above-mentioned chelating agent include aminocarboxylic acid-based chelating agents and organic phosphonic acid-based chelating agents. Suitable examples of the chelating agent include, for example, ethylenediamine (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Examples of the above-mentioned antiseptic and antifungal agent include isothiazoline-based compounds, parabens, phenoxyethanol, and the like.

The polishing composition disclosed herein preferably contains substantially no oxidizing agent. This is because if the polishing composition contains an oxidizing agent, the polishing composition is supplied to a substrate (eg, a silicon wafer), and the surface of the substrate is oxidized to generate an oxide film, and the polishing rate may be reduced accordingly. Specific examples of the oxidizing agent here include hydrogen peroxide (H ₂ O ₂ ), sodium persulfate, ammonium persulfate, sodium dichloroisocyanurate, and the like. In addition, a polishing composition does not contain an oxidizing agent substantially, and means that an oxidizing agent is not contained intentionally at least. Therefore, it is unavoidable to contain trace amounts from raw materials or production methods (for example, the molar concentration of the oxidizing agent in the polishing composition is 0.0005 mol/L or less, preferably 0.0001 mol/L or less, preferably 0.00001 mol/L). L or less, particularly preferably 0.000001 mol/L or less), a polishing composition of an oxidizing agent is also included in the concept of a polishing composition that does not substantially contain an oxidizing agent here.

＜pH＞ The pH of the polishing composition disclosed here is not particularly limited, and an appropriate pH can be adopted according to the type of substrate or, in the case of including abrasive grains, according to the type of abrasive grains, and the like. In several aspects, the pH of the polishing composition is suitably 8.0 or more, preferably 8.5 or more, and more preferably 9.0 or more. When the pH of the polishing composition becomes high, the polishing rate tends to increase. On the other hand, in the case where the polishing composition contains abrasive grains, for example, from the viewpoint of preventing the dissolution of the abrasive grains (for example, silica particles) and suppressing the reduction of the mechanical polishing effect, the pH of the polishing composition is generally 12.0 or less is suitable, 11.0 or less is more preferable, 10.8 or less is more preferable, and 10.5 or less is more preferable.

In addition, in the technique disclosed here, the pH of the polishing composition can be determined by using a pH meter (for example, a glass electrode type hydrogen ion concentration indicator (model F-72) manufactured by Horiba Corporation), and using a standard buffer solution (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)), at 3 o'clock After calibration, the glass electrode was placed in the composition of the measurement object, and the value after stabilization was measured for 2 minutes or more.

＜Polishing fluid＞ The polishing composition disclosed here is typically supplied to the surface of a substrate in the form of a polishing liquid containing the polishing composition, and is used for polishing the substrate. The above-mentioned polishing liquid can be prepared, for example, by diluting any of the polishing compositions disclosed herein (typically, diluted with water). Alternatively, the polishing composition can be used as it is as a polishing liquid. That is, the concept of the polishing composition in the technology disclosed here includes a polishing liquid (working slurry) that is supplied to a substrate and used to polish the substrate, and a concentrated liquid that is diluted and used as a polishing liquid (a polishing liquid). stock solution) both. Other examples of the polishing liquid containing the polishing composition disclosed here include polishing liquids prepared by adjusting the pH of the composition.

＜Concentrate＞ The polishing composition disclosed here may be in a concentrated form (that is, in the form of a concentrated solution of polishing liquid) before being supplied to the substrate. The polishing composition in such a concentrated form is advantageous from the viewpoints of convenience at the time of manufacture, distribution, and storage, and cost reduction. The concentration ratio is not particularly limited, but can be set to, for example, about 2 times to 100 times in terms of volume, and usually about 5 times to 50 times (for example, about 10 times to 40 times) is appropriate. Such a concentrated liquid can be diluted at a desired timing to prepare a polishing liquid (working slurry), and can be used in a state of supplying the polishing liquid to a substrate. The above-mentioned dilution can be carried out, for example, by adding water to the above-mentioned concentrate and mixing.

In addition, in the aspect in which the polishing composition contains abrasive grains, when the polishing composition (that is, the concentrated liquid) is diluted and used for polishing, the content of the abrasive grains in the above-mentioned concentrated liquid can be set to, for example, 25% by weight or less. From the viewpoint of dispersion stability, filterability, etc. of the polishing composition, the content is usually preferably 20% by weight or less, preferably 15% by weight or less. In a suitable aspect, the content of abrasive particles may be set at 10 wt % or less, or 5 wt % or less. In addition, the content of the abrasive grains in the concentrate may be, for example, 0.1% by weight or more, preferably 0.5% by weight or more, and preferably 0.5% by weight or more, from the viewpoints of convenience in production, distribution, storage, and cost reduction, etc. 0.7% by weight or more, more preferably 1% by weight or more.

<Preparation of polishing composition> Among the techniques disclosed herein, the abrasive compositions used may be in a single-dose form, or in a multi-dose form, primarily represented by a two-dose form. For example, in an aspect in which the polishing composition contains abrasive grains, a part A containing at least abrasive grains and a part B containing at least a part of the remaining components among the constituent components of the polishing composition can be mixed, and they can be mixed as necessary. It is constituted by mixing and diluting at an appropriate timing to prepare a polishing liquid.

The preparation method of the polishing composition is not particularly limited. What is necessary is just to mix each component which comprises the composition for grinding|polishing using the well-known mixing apparatus, such as a blade mixer, an ultrasonic disperser, and a homogenizer, for example. The aspect of mixing these components is not particularly limited, and for example, all the components may be mixed at once, or they may be mixed in an appropriately set order.

＜Use＞ The polishing composition disclosed here can be suitably used for polishing substrates of various materials and shapes. The material of the substrate can be metals or semi-metals such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, stainless steel, etc., or their alloys; glass-like substances such as quartz glass, aluminosilicate glass, glassy carbon, etc. ; Ceramic materials of alumina, silicon dioxide, sapphire, silicon nitride, tantalum nitride, titanium carbide, etc.; compound semiconductor substrate materials of silicon carbide, gallium nitride, gallium arsenide, etc.; resins such as polyimide resins materials, etc. A substrate made of a plurality of these materials may also be used. The shape of the substrate is not particularly limited. The polishing composition disclosed here can be suitably used for polishing a flat substrate such as a plate or a polyhedron, or polishing an edge of a substrate (eg, polishing a wafer edge).

The polishing composition disclosed herein is particularly suitable for polishing a surface formed of silicon (typically, polishing a silicon wafer). A typical example of the so-called silicon wafer here is a single crystal silicon wafer, such as a single crystal silicon wafer obtained by slicing a single crystal silicon ingot.

The polishing compositions disclosed herein are suitable for use in polishing steps for substrates such as silicon wafers. Before the polishing step using the polishing composition disclosed herein, a general treatment that can be applied to the substrate may be performed in a step upstream of the polishing step, such as rough grinding or etching.

The polishing composition disclosed herein is effective in the finishing step of a substrate (eg, silicon wafer) or its preceding polishing step, and is particularly preferably used in the finishing polishing step. Here, the finishing polishing step refers to the final polishing step in the manufacturing process of the target object (ie, a step in which polishing is not performed after this step). The grinding composition disclosed here can also be used in the polishing step upstream of the finishing polishing (referring to the pre-grinding step between the rough grinding step and the final grinding step, typically including at least one polishing step, even may include 2, 3, etc. polishing steps), eg, a polishing step performed prior to finishing polishing.

The polishing composition disclosed herein is suitable, for example, for polishing (typically finishing polishing or prior polishing) of a silicon wafer whose surface state is adjusted to a surface roughness of 0.01 nm to 100 nm by an upstream step. effect. Ideal for finishing polishing. The surface roughness Ra of a board|substrate can be measured using the laser scanning type surface roughness meter "TMS-3000WRC" by Schmitt Measurement System Inc., for example.

＜Grinding＞ The polishing composition disclosed here can be used for polishing a substrate in an aspect including the following operations, for example. A suitable aspect of a method for polishing a silicon wafer as a substrate using the polishing composition disclosed herein will be described below. That is, a polishing liquid containing any of the polishing compositions disclosed herein is prepared. When preparing the above-mentioned polishing liquid, operations such as concentration adjustment (for example, dilution), pH adjustment, etc. of the polishing composition may be included to prepare the polishing liquid. Alternatively, the polishing composition can be used as it is as a polishing liquid.

Next, this polishing liquid is supplied to the substrate, and is polished by an ordinary method. For example, in the case of finishing polishing a silicon wafer, typically, the silicon wafer that has undergone a rough polishing step is set in a general polishing apparatus, and the surface of the silicon wafer to be polished is supplied to the surface of the polishing object through the polishing pad of the polishing apparatus. liquid. Typically, the above-mentioned polishing liquid is continuously supplied, and at the same time, the polishing pad is pressed against the surface of the polishing object of the silicon wafer, so that the two are moved (eg, rotated) relative to each other. After this polishing step, the polishing of the substrate ends.

The polishing pad used in the above-mentioned polishing step is not particularly limited. For example, a polishing pad of a foamed polyurethane type, a nonwoven type, a suede type, or the like can be used. Each polishing pad may contain abrasive particles or be free of abrasive particles. Generally, a polishing pad that does not contain abrasive particles is suitable.

The substrate after polishing with the polishing composition disclosed herein is typically washed. Cleaning can be performed with an appropriate cleaning solution. The cleaning solution to be used is not particularly limited. For example, in the field of semiconductors, general SC-1 cleaning solutions (ammonium hydroxide (NH ₄ OH) and hydrogen peroxide (H ₂ O ₂ ) can be used. mixed solution with water (H ₂ O), SC-2 cleaning solution (mixed solution of HCl, H ₂ O ₂ and H ₂ O), etc. The temperature of the cleaning solution can be set, for example, in a range from room temperature (typically, about 15°C to 25°C) or more to about 90°C. From the viewpoint of improving the cleaning effect, it is suitable to use a cleaning solution at a temperature of about 50°C to 85°C.

As described above, the techniques disclosed herein include methods for providing an abrasive (eg, a method for manufacturing a silicon wafer) comprising a polishing step (preferably a finish polishing) using any of the above-mentioned polishing methods, and by the method Manufactured abrasives (such as silicon wafers). [Example]

Several embodiments of the present invention are described below, but the present invention is not intended to be limited to the contents disclosed in the embodiments. In addition, in the following description, unless otherwise noted, "%" is the basis of weight.

<Preparation of Polishing Composition> (Example 1) Abrasive particles, a surfactant, a basic compound, and deionized water (DIW) were mixed to prepare a concentrate of the polishing composition in this example. As abrasive grains, colloidal silica (average primary particle size: 27 nm) was used. Surfactant using the above formula (1), R ¹ and R ² are both lauryl, R ³ and R ⁴ are polyethylene oxide (R ³ and R ⁴ in the ethylene oxide addition molar number The total of: 25), a compound with a molecular weight of about 1680. The basic compound uses ammonia. The concentration of the obtained polishing composition is diluted with deionized water to a volume ratio of 20 times, and the concentration of the abrasive particles is 0.175%, the concentration of the surfactant is 0.005%, and the concentration of the basic compound is 0.005% or less. The polishing composition related to this example.

(Comparative Example 1) The polishing composition related to this example was prepared in the same manner as in Example 1, except that polyoxyethylene decyl ether (C10EO5) having a molar number of 5 added with ethylene oxide was used as the surfactant. thing. The surfactants used in this example are shown in Table 1. The number of hydrophilic groups and the number of hydrophobic groups in one molecule are both 1, and the molecular weight is 378.

(Example 2) The abrasive grains, surfactant, water-soluble polymer, basic compound, and deionized water were mixed to prepare a concentrated solution of the polishing composition related to this example. As abrasive grains, colloidal silica (average primary particle size: 27 nm) was used. Surfactant using the above formula (1), R ¹ and R ² are both lauryl, R ³ and R ⁴ are both hydrogen atoms (in the "EO added moles" column in the table "-" , the same in Table 3), a compound with a molecular weight of about 580. As the water-soluble polymer, acetalized polyvinyl alcohol (ac-PVA) having a weight average molecular weight (Mw) of about 1.0×10 ⁴ was used. The basic compound uses ammonia. The concentration of the obtained polishing composition was diluted with deionized water to a volume ratio of 20 times, and the concentration of abrasive particles was 0.175%, the concentration of surfactant was 0.005%, and the concentration of water-soluble polymer was 0.005%. , The polishing composition related to this example with the concentration of the basic compound being 0.005%.

(Example 3) Except that R ¹ and R ² of the above formula (1) are both lauryl groups, R ³ and R ⁴ are both polyethylene oxide (the ethylene oxide in R ³ and R ⁴ is not added). Total number of ears: 7) The polishing composition related to this example was prepared in the same manner as in Example 2, except that the compound having a molecular weight of about 900 was used as a surfactant.

(Example 4) The surfactant used in Example 1 was used as the surfactant, and its concentration was set at 0.001%. Other than that, it carried out similarly to Example 2, and prepared the polishing composition concerning this example.

(Example 5) The polishing composition according to this example was prepared in the same manner as in Example 4, except that the concentration of the surfactant was set to 0.005%.

(Comparative Examples 2 and 3) Except using the ethylene oxide addition polyoxyethylene decyl ether (C10EO5) with a molar number of 5 used in Comparative Example 1 as a surfactant, and its concentration was set at 0.001% (Comparative Example 2), 0.005 % (Comparative Example 3), it carried out similarly to Example 2, and prepared the polishing composition concerning each example.

(Example 6) The abrasive grains, surfactant, water-soluble polymer, basic compound, and deionized water were mixed to prepare a concentrated solution of the polishing composition related to this example. As abrasive grains, colloidal silica (average primary particle size: 27 nm) was used. As the surfactant, the compound used in Example 2 was used. As the water-soluble polymer, polyacryloylmorpholine (PACMO) with Mw of about 4.7×10 ⁵ and acetalized polyvinyl alcohol (ac-PVA) with Mw of about 1.0×10 ⁴ were used. The basic compound uses ammonia. The concentration of the obtained polishing composition was diluted with deionized water to a volume ratio of 20 times, and the concentration of abrasive particles was 0.169%, the concentration of surfactant was 0.005%, the concentration of PACMO was 0.0083%, and the concentration of ac- The polishing composition according to this example in which the concentration of the PVA is 0.005% and the concentration of the basic compound is 0.005%.

(Examples 7 and 8) The polishing composition related to each example was prepared in the same manner as in Example 6, except that the compounds used in Examples 3 and 4 were used as surfactants, respectively.

(Comparative Example 4) This example was prepared in the same manner as in Example 6, except that the ethylene oxide-added polyoxyethylene decyl ether (C10EO5) having a molar number of 5 used in Comparative Example 1 was used as a surfactant. The related polishing composition.

＜Polishing of silicon wafers＞ A commercially available single crystal silicon wafer (conductivity type: P type, crystal orientation: <100>, no COP (Crystal Originated Particle: crystal defect)) having a diameter of 200 mm after rough grinding and etching was pre-polished according to the following grinding conditions 1 Take the prepared silicon wafer as the substrate. Pre-polishing was performed using a polishing liquid containing 1.0% abrasive particles (colloidal silica with an average primary particle size of 42 nm) and 0.068% potassium hydroxide in deionized water.

[grinding condition 1] Grinding device: Monolithic grinding device manufactured by Okamoto Machinery Manufacturing Co., Ltd., model "PNX-322" Grinding load: 15kPa Fixed plate speed: 30rpm The rotational speed of the grinding head (carrier): 30rpm Polishing pad: manufactured by FUJIBO Ehime Co., Ltd., product name "FP55" Supply rate of pre-grinding liquid: 550mL/min Temperature of pre-grinding liquid: 20℃ Temperature of plate cooling water: 20℃ Grinding time: 3min

The above-mentioned pre-polished silicon wafer was polished according to the following polishing condition 2 using the polishing composition according to each of the above-prepared examples as polishing liquids.

[grinding condition 2] Grinding device: Monolithic grinding device manufactured by Okamoto Machinery Manufacturing Co., Ltd., model "PNX-322" Grinding load: 15kPa Fixed plate speed: 30rpm The rotational speed of the grinding head (carrier): 30rpm Polishing pad: manufactured by FUJIBO Ehime Co., Ltd., product name "POLYPAS275NX" The supply rate of the grinding liquid: 400mL/min The temperature of the polishing liquid: 20℃ Temperature of plate cooling water: 20℃ Grinding time: 4min

The polished silicon wafer was removed from the polishing apparatus, and washed with NH ₄ OH (29%): H ₂ O ₂ (31%): deionized water (DIW) = 1:1:12 (volume ratio) solution to wash (SC-1 wash). Specifically, the first and second two cleaning tanks were prepared, and the cleaning liquid was filled in these cleaning tanks, and the temperature was maintained at 60°C. The polished silicon wafer was immersed in the first cleaning tank for 5 minutes, then immersed in ultrapure water, passed through a cleaning tank applying ultrasonic vibration, immersed in the second cleaning tank for 5 minutes, and then immersed in ultrapure water. The water is passed through a cleaning tank to which ultrasonic vibration is applied, and is dried using a centrifugal dryer.

<Haze measurement> The haze (ppm) of the cleaned silicon wafer surface was measured in the DWO mode using a wafer inspection apparatus manufactured by KLA-Tencor, trade name "Surfscan SP2 ^XP ". The obtained results were converted into relative values (haze ratio) with the haze value of Comparative Example 1 as 100% and disclosed in Table 1, and converted into relative values with the haze value of Comparative Example 2 as 100% ( The haze ratio) is shown in Table 2, and it is converted into a relative value (haze ratio) based on the haze value of Comparative Example 4 as 100% and shown in Table 3. The smaller the value of the haze ratio, the higher the haze improvement effect. In addition, the surfactant (C10EO5) of the comparison object also has a certain haze improvement effect, so the haze ratio of Comparative Examples 1, 2, and 4 containing the surfactant (C10EO5) is 120% or less based on the relative value. In this case, it was determined that the haze value could be maintained or improved.

<grinding speed> A silicon wafer with a diameter of 200 mm (conductivity type: P type, crystal orientation: <100>, no COP (Crystal Originated Particle: crystal defect)) was prepared as a polishing object and immersed in an HF aqueous solution (HF concentration: 2%) for 60 The oxide film was removed within seconds, and polishing was performed in accordance with the following polishing conditions 3 using the polishing composition related to each example as polishing liquid.

[grinding condition 3] Grinding device: Monolithic grinding device manufactured by Okamoto Machinery Manufacturing Co., Ltd., model "PNX-322" Grinding load: 15kPa Fixed plate speed: 30rpm The rotational speed of the grinding head (carrier): 30rpm Polishing pad: manufactured by FUJIBO Ehime Co., Ltd., product name "POLYPAS275NX" The supply rate of the grinding liquid: 400mL/min The temperature of the polishing liquid: 20℃ Temperature of plate cooling water: 20℃ Grinding time: 10min

The polished silicon wafer was removed from the polishing apparatus, and immersed in a cleaning solution of NH ₄ OH (29%): H ₂ O ₂ (31%): deionized water = 1:1:12 (volume ratio) After 5 minutes, washing (SC-1 washing) was carried out. Then, it was immersed in deionized water while the ultrasonic oscillator was operating, and was dried using a centrifugal dryer.

(Evaluate) The weight of the silicon wafer before and after polishing was measured, and the polishing rate [nm/min] was obtained from the difference in weight and the specific gravity of silicon. The obtained results were converted into relative values with the polishing rate of Comparative Example 1 as 100%, and shown in Table 1, and converted into relative values with the polishing rate of Comparative Example 2 as 100%, shown in Table 2, and converted into Table 3 shows the relative value of the polishing rate of Comparative Example 4 as 100%. Larger values represent higher grinding rates.

As shown in Tables 1 to 3, the polishing compositions of Examples 1 to 8 used surfactants having two hydrophilic groups and two hydrophobic groups in one molecule. Compared with Comparative Examples 1 to 4 containing the surfactant of the specific structure described above, the haze value was maintained or improved within a predetermined range (relative value was 120% or less), and the polishing rate tended to increase. From the above results, it was found that a composition suitable for polishing can be produced by using a surfactant having two hydrophilic groups and two hydrophobic groups in one molecule.

Specific examples of the present invention have been described above in detail, but these are merely illustrative and do not limit the scope of the patent application. The technology described in the scope of claims includes various modifications and changes of the specific examples exemplified above.

Claims (8)

A grinding composition comprising an alkaline compound and water, It further includes a surfactant having two hydrophilic groups and two hydrophobic groups in one molecule. The polishing composition according to claim 1, wherein the surfactant is a compound represented by the following formula (1),

(In formula (1), R ¹ and R ² are each independently an alkyl group, and R ³ and R ⁴ are each independently a hydrogen atom or an oxyalkylene unit). The polishing composition according to claim 1 or 2, further comprising abrasive grains. The polishing composition according to claim 3, comprising silica particles as the abrasive grains. The polishing composition according to any one of claims 1 to 4, further comprising a water-soluble polymer. The polishing composition according to any one of claims 1 to 5, wherein the pH of the polishing composition is 8.0 or more and 12.0 or less. The polishing composition according to any one of claims 1 to 6, which is used for polishing a silicon wafer. A method for polishing an object to be polished, comprising the step of polishing the object to be polished using the polishing composition according to any one of claims 1 to 7.