Polishing composition, polishing method, and method for manufacturing semiconductor substrates

Abstract

To provide means enabling residue on the surface of a polishing-target to be sufficiently removed while polishing the surface of the polishing-target at slow speed.SOLUTION: A composition for polishing is provided, including: an anionic water-soluble polymer that is a copolymer including anion-modified colloidal silica, a dispersion medium, a constitutional unit having a sulfonic acid group or a salt thereof, and a constitutional unit having a carboxy group or a salt thereof; polypropylene glycol having a weight average molecular weight of 200 to 700; a nitrogen-free nonionic polymer other than the polypropylene glycol having a weight average molecular weight of 200 to 700; and a nitrogen-containing nonionic polymer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polishing composition, a polishing method, and a method for manufacturing a semiconductor substrate.

Background Art

[0002] Due to the high integration brought about by the miniaturization of the LSI (Large Scale Integration) manufacturing process, electronic devices such as computers have achieved high performance such as miniaturization, multifunctionality, and high speed. In such new microfabrication technologies accompanying the high integration of LSI, the chemical mechanical polishing (CMP) method is used.

[0003] In general, the formation of metal plugs and wirings in semiconductor devices is performed by forming a conductor layer made of metal on a film such as a silicon oxide film, a silicon nitride film, or a polysilicon film in which recesses are formed, and then removing a part of the conductor layer by polishing until the above film is exposed. This polishing process is roughly classified into a main (bulk) polishing process for performing polishing to remove most of the object to be removed and a finish (buff) polishing process for finish-polishing the object (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, in some cases, the above film has been thinned, and in the finish polishing process, there is an increasing need for means to improve the surface state of the polishing object by reducing the polishing rate and gently polishing the above film. Also, in the finish polishing process, it is required to sufficiently remove residues on the surface of the polishing object.

[0006] Therefore, the present invention aims to provide a means that can thoroughly remove surface residue from an object to be polished while polishing the object at a slow speed. [Means for solving the problem]

[0007] In view of the above problems, the present inventors conducted diligent studies. As a result, they found that the above problems can be solved by an abrasive composition comprising an anionic water-soluble polymer which is a copolymer containing anionic-modified colloidal silica, a dispersion medium, a constituent unit having a sulfonic acid group or a salt thereof, a constituent unit having a carboxyl group or a salt thereof, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than the polypropylene glycol having a weight-average molecular weight of 200 to 700, and a nitrogen-containing nonionic polymer, and thus completed the present invention. [Effects of the Invention]

[0008] The present invention provides a means for thoroughly removing residue from the surface of an object to be polished while polishing the object at a slow speed. [Modes for carrying out the invention]

[0009] The present invention provides an abrasive composition comprising: an anionic water-soluble polymer, which is a copolymer containing anionic-modified colloidal silica; a dispersion medium; a structural unit having a sulfonic acid group or a salt thereof; a structural unit having a carboxyl group or a salt thereof; polypropylene glycol having a weight-average molecular weight of 200 to 700; a nitrogen-free nonionic polymer other than the polypropylene glycol having a weight-average molecular weight of 200 to 700; and a nitrogen-containing nonionic polymer. The abrasive composition of the present invention provides a means to thoroughly remove residue remaining on the surface of an object to be polished while gently polishing the surface.

[0010] The inventors hypothesize the following mechanism by which the polishing composition according to the present invention slows down the polishing speed on the object to be polished and further removes residue from the surface of the object to be polished.

[0011] In other words, the various polymers contained in the polishing composition of the present invention (anionic water-soluble polymer, polypropylene glycol with a weight-average molecular weight of 200 to 700, nitrogen-free nonionic polymers other than polypropylene glycol with a weight-average molecular weight of 200 to 700, and nitrogen-containing nonionic polymers) act on the surface of the object to be polished, thereby slowing down the polishing speed of the object's surface and removing residue from the surface of the object. Although the details of these mechanisms are unknown, it is thought that the configuration of the present invention allows the various polymers to be more effectively adsorbed onto the object to be polished, thereby adequately protecting the surface of the object from abrasive particles (anionic-modified colloidal silica) and slowing down the polishing speed. Furthermore, it is thought that the more effectively the various polymers are adsorbed onto the object to be polished, the more efficiently residue on the surface of the object can be removed, and the re-adhesion of residue (contaminants) to the surface can also be prevented. Furthermore, with the configuration of the present invention, various polymers adsorbed on the surface of the object to be polished can be easily detached from the surface of the object to be polished, and it is possible to achieve a state where various polymers adsorbed on the surface of the object to be polished do not become residue, or do not become residue at all. For the reasons described above, it is believed that the polishing composition of the present invention can slow down the polishing speed of the object to be polished by the abrasive grains (anionically modified colloidal silica) and furthermore, it can sufficiently remove the residue from the surface.

[0012] It should be noted that the above mechanism is based on speculation, and the present invention is not limited in any way to the above mechanism.

[0013] The polishing composition according to the present invention is typically supplied to an object to be polished in the form of a polishing liquid containing the polishing composition and used to polish the object. The polishing composition according to the present invention may be used as a polishing liquid after being diluted (typically diluted with water), or it may be used as a polishing liquid as is. That is, the concept of the polishing composition according to the present invention encompasses both a polishing composition (working slurry) supplied to an object to be polished and used to polish the object, and a concentrated liquid (working slurry stock) that is diluted and used for polishing. The concentration ratio of the concentrated liquid can be, for example, about 2 to 100 times by volume, and is usually about 5 to 50 times appropriate.

[0014] The embodiments of the present invention will be described in detail below, but the present invention is not limited to the embodiments described below. Unless otherwise specified in this specification, operations and measurements of physical properties, etc., are performed under conditions of room temperature (20°C to 25°C) and relative humidity of 40%RH to 50%RH.

[0015] <Residue> In this specification, "residue" refers to foreign matter adhering to the surface of an object to be polished. Examples of residue are not particularly limited, but include, for example, organic residue described later, particle residue derived from abrasive grains contained in the polishing composition, residue consisting of components other than particle residue and organic residue, mixtures of particle residue and organic residue, and other types of residue.

[0016] The total residue count refers to the total number of all residues, regardless of type. The total residue count can be measured using a wafer defect inspection device (optical inspection machine Surfscan® SP5; manufactured by KLA-Tencor Co., Ltd.). Details of the method for measuring the residue count are described in the examples below.

[0017] In this specification, "organic residue" refers to foreign matter adhering to the surface of an object to be polished, consisting of organic substances such as low-molecular-weight organic compounds and high-molecular-weight organic compounds, as well as organic salts and the like.

[0018] Organic residues adhering to the object to be polished include, for example, pad debris generated from the pad used in the polishing process, or components derived from additives contained in the polishing composition used in the polishing process.

[0019] Since the color and shape of organic residues and other foreign substances are significantly different, the determination of whether a foreign substance is an organic residue can be visually made by SEM observation. Also, the determination of whether a foreign substance is an organic residue may, if necessary, be made by elemental analysis using an energy dispersive X-ray analyzer (EDX). The number of organic residues can be measured using a wafer defect inspection apparatus and SEM or EDX elemental analysis.

[0020] <Object to be polished> In this specification, the object to be polished means an object to be polished using the polishing composition according to the present invention. Specific examples of the object to be polished include, but are not particularly limited to, films formed on the surface of a semiconductor substrate or the like.

[0021] The material contained in the object to be polished according to the present invention is not particularly limited, and examples include carbon-containing silicon such as silicon oxide, silicon nitride (SiN), silicon carbonitride (SiCN), polycrystalline silicon (polysilicon), amorphous silicon (amorphous silicon), silicon materials doped with impurities, simple metals, alloys, metal nitrides, compound semiconductors such as SiGe, and the like. Among these, it is preferable that at least one of silicon nitride, silicon oxide, and polysilicon is included.

[0022] Examples of films containing silicon oxide include, for example, TEOS (Tetraethyl Orthosilicate) type silicon oxide films (hereinafter also simply referred to as "TEOS films") generated using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma) films, USG (Undoped Silicate Glass) films, PSG (Phosphorus Silicate Glass) films, BPSG (Boron-Phospho Silicate Glass) films, RTO (Rapid Thermal Oxidation films), and the like. The film containing silicon oxide included in the object to be polished may be a single type or a combination of two or more types.

[0023] In addition, the polishing composition according to one embodiment of the present invention can also gently reduce the polishing rate of the surface of the object to be polished and reduce the residues on the surface even for an object to be polished that contains both a hydrophilic material and a hydrophobic material. Here, the hydrophilic material refers to a material having a contact angle with water of less than 50°, and the hydrophobic material refers to a material having a contact angle with water of 5° or more. The contact angle with water is a value measured by a contact angle meter DropMaster (DMo-501) manufactured by Kyowa Interface Science Co., Ltd.

[0024] Specific examples of the hydrophilic material include, for example, silicon oxide, silicon nitride, silicon oxynitride, tungsten, titanium nitride, tantalum nitride, boron-containing silicon, and the like. These hydrophilic materials may be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the hydrophilic material is silicon oxide and / or silicon nitride. Specific examples of the hydrophobic material include, for example, polycrystalline silicon, single crystal silicon, amorphous silicon, carbon-containing silicon, and the like. These hydrophobic materials may be used alone or in combination of two or more. According to a preferred embodiment of the present invention, the hydrophobic material is polycrystalline silicon.

[0025] In other words, according to one preferred embodiment of the present invention, the hydrophilic material is silicon oxide and the hydrophobic material is polycrystalline silicon. Furthermore, according to one preferred embodiment of the present invention, the hydrophilic material is silicon nitride and the hydrophobic material is polycrystalline silicon. Moreover, according to one preferred embodiment of the present invention, the hydrophilic material is silicon oxide and silicon nitride and the hydrophobic material is polycrystalline silicon.

[0026] <Polishing composition> The polishing composition according to the present invention comprises anionically modified colloidal silica, a dispersion medium, an anionic water-soluble polymer, polypropylene glycol, a nitrogen-free nonionic polymer, and a nitrogen-containing nonionic polymer. In this specification, "nonionic polymer" refers to a polymer that does not have anionic groups such as carboxyl groups, sulfonic acid groups, or phosphate groups, or cationic groups such as amino groups or quaternary ammonium groups in its molecule. "Anionic polymer" refers to a polymer that has anionic groups such as carboxyl groups, sulfonic acid groups, or phosphate groups in its molecule. Each polymer will be described below.

[0027] (Anionically modified colloidal silica) The polishing composition according to the present invention contains anionically modified colloidal silica as abrasive particles. Anionically modified colloidal silica is colloidal silica whose surface is modified with anionic groups, and in the polishing composition, it has the effect of mechanically polishing the object to be polished.

[0028] Preferred anionically modified colloidal silica includes colloidal silica in which anionic groups such as carboxyl groups, sulfonic acid groups, phosphonic acid groups, and aluminic acid groups are immobilized on the surface. The method for producing such colloidal silica having anionic groups is not particularly limited, and one example is a method of reacting colloidal silica with a silane coupling agent having anionic groups at its terminals.

[0029] For example, if you want to immobilize sulfonic acid groups on colloidal silica, you can do so by the method described in “Sulfonic acid-functionalized silica through of thiol groups”, Chem.Commun. 246-247 (2003). Specifically, by coupling a silane coupling agent having a thiol group, such as 3-mercaptopropyltrimethoxysilane, to colloidal silica and then oxidizing the thiol group with hydrogen peroxide, you can obtain colloidal silica on which sulfonic acid groups are immobilized on the surface (sulfonic acid-modified colloidal silica).

[0030] If the goal is to immobilize a carboxyl group on colloidal silica, this can be done, for example, by the method described in “Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel”, Chemistry Letters, 3,228-229 (2000). Specifically, by coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to colloidal silica and then irradiating it with light, colloidal silica with an immobilized carboxyl group on its surface (carboxylic acid-modified colloidal silica) can be obtained.

[0031] In one embodiment of the present invention, the average primary particle diameter of the anion-modified colloidal silica is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, even more preferably 25 nm or more, and even more preferably 30 nm or more. In one embodiment of the present invention, the average primary particle diameter of the anion-modified colloidal silica is preferably 60 nm or less, more preferably 50 nm or less, and even more preferably 40 nm or less. The anion-modified colloidal silica having the above average primary particle diameter has the effect of reducing scratches, decreasing the number of defects (residues), and improving the polishing speed. In the present invention, the average primary particle diameter is the value measured by the method described in the examples.

[0032] In one embodiment of the present invention, the average secondary particle diameter of the anion-modified colloidal silica is preferably 40 nm or more, more preferably 45 nm or more, even more preferably 50 nm or more, even more preferably 55 nm or more, even more preferably 60 nm or more, and even more preferably 65 nm or more. In one embodiment of the present invention, the average secondary particle diameter of the anion-modified colloidal silica is preferably less than 100 nm, more preferably 90 nm or less, even more preferably 80 nm or less, and even more preferably 75 nm or less. The anion-modified colloidal silica having the above average secondary particle diameter has the effect of improving the polishing speed. In the present invention, the average secondary particle diameter is the value measured by the method described in the examples.

[0033] In one embodiment of the present invention, in the particle size distribution of anion-modified colloidal silica in the polishing composition, the lower limit of the ratio of the particle diameter D90 when the cumulative particle mass from the fine particle side reaches 90% of the total particle mass to the particle diameter D10 when it reaches 10% (hereinafter also simply referred to as "D90 / D10") is preferably 1.3 or higher, more preferably 1.4 or higher, even more preferably 1.5 or higher, and even more preferably 1.6 or higher. Having such a lower limit has the effect of improving the polishing speed. In one embodiment of the present invention, the upper limit of D90 / D10 of anion-modified colloidal silica is preferably 4.0 or lower, more preferably 3.5 or lower, even more preferably 3.0 or lower, and even more preferably 2.0 or lower.

[0034] In one embodiment of the present invention, the lower limit of the aspect ratio of the anion-modified colloidal silica is preferably 1.05 or higher, more preferably 1.10 or higher, and even more preferably 1.15 or higher. This embodiment has the technical effect of improving the polishing speed. In another embodiment of the present invention, the upper limit of the aspect ratio of the anion-modified colloidal silica is preferably 5 or lower, more preferably 2 or lower, and even more preferably 1.5 or lower. This embodiment has the technical effect of improving dispersion stability and reducing the number of defects (residues). The aspect ratio of the anion-modified colloidal silica can be determined by randomly sampling 300 abrasive particle images measured by FE-SEM and using the average value of the aspect ratio (major axis / minor axis).

[0035] The content of anionically modified colloidal silica in the polishing composition according to one embodiment of the present invention is not particularly limited. In the case of a polishing composition used as is as a polishing liquid for polishing an object to be polished (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or polishing slurry), from the viewpoint of reducing surface roughness after polishing, the lower limit of the content of anionically modified colloidal silica in the polishing composition is preferably more than 0.001% by mass, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and most preferably 0.8% by mass or more, based on the total mass of the polishing composition. Furthermore, the upper limit of the content of anionically modified colloidal silica in the polishing composition used as a polishing liquid for polishing the object to be polished is preferably 10% by mass or less, more preferably 5.0% by mass or less, even more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, particularly preferably 1.5% by mass or less, and most preferably 1.3% by mass or less, from the viewpoint of reducing polishing speed, reducing scratches, and reducing the number of defects (residues). In this specification, when a substance is included in two or more types, the description refers to the total amount. In other words, the content of anionically modified colloidal silica in the polishing composition is preferably more than 0.001% by mass and 10% by mass or less, more preferably 0.005% by mass or more and 5.0% by mass or less, even more preferably 0.01% by mass or more and 4.0% by mass or less, even more preferably 0.05% by mass or more and 3.0% by mass or less, even more preferably 0.1% by mass or more and 2.0% by mass or less, even more preferably 0.3% by mass or more and 2.0% by mass or less, particularly preferably 0.5% by mass or more and 1.5% by mass or less, and most preferably 0.8% by mass or more and 1.3% by mass or less, based on the total mass of the polishing composition.

[0036] Furthermore, in the case of polishing compositions used after dilution for polishing (i.e., concentrated liquids, working slurry stocks), the lower limit of the anionically modified colloidal silica content is preferably more than 1% by mass, and more preferably 2% by mass or more, relative to the total mass of the polishing composition, from the viewpoint of reducing surface roughness after polishing and taking advantage of the benefits of using concentrated liquids. Furthermore, the upper limit of the anionically modified colloidal silica content in polishing compositions used after dilution for polishing is usually appropriate to be 30% by mass or less, and more preferably 25% by mass or less, from the viewpoint of storage stability and filterability. In this specification, when a substance is included in two or more forms, the description of the content of a substance refers to its total amount.

[0037] The polishing composition according to the present invention may further contain other abrasive particles other than anionically modified colloidal silica, to the extent that they do not impair the effects of the present invention. Such other abrasive particles may be inorganic particles, organic particles, or organic-inorganic composite particles. Specific examples of inorganic particles include, for example, unmodified silica, cationically modified silica, particles made of metal oxides such as alumina, ceria, and titania, silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of organic particles include, for example, polymethyl methacrylate (PMMA) particles. These other abrasive particles may be used individually or in combination of two or more types. Furthermore, these other abrasive particles may be commercially available or synthetically produced.

[0038] However, the content of other abrasive grains is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less, relative to the total mass of the abrasive grains. Most preferably, the content of other abrasive grains is 0% by mass, that is, the abrasive grains consist only of anionically modified colloidal silica.

[0039] (Anionic water-soluble polymer) The polishing composition according to the present invention contains an anionic water-soluble polymer, which is a copolymer comprising a structural unit having a sulfonic acid group or a salt thereof, and a structural unit having a carboxyl group or a salt thereof. In the polishing composition according to the present invention, the anionic water-soluble polymer acts as a dispersant. Furthermore, the anionic polymer is adsorbed onto the surface of the object to be polished (particularly the object to be polished containing silicon nitride), and moderately protects the surface from polishing by abrasive particles (anionic-modified colloidal silica), thereby slowing down the polishing speed. Moreover, because the polishing composition according to the present invention contains the anionic polymer, nitrogen-free nonionic polymers and nitrogen-containing nonionic polymers adsorbed onto the surface of the object to be polished (particularly the object to be polished containing silicon nitride) become more easily redissolved in the polishing composition, making it easier for these polymers to detach from the surface of the object to be polished, and as a result, the residue on the surface of the object to be polished can be reduced.

[0040] In one embodiment of the present invention, examples of monomers having sulfonic acid groups constituting the copolymer include, for example, the polyalkylene glycol monomer (A) described in paragraphs "0019" to "0036" of Japanese Patent Application Publication No. 2015-168770, and the sulfonic acid group-containing monomer (C) described in paragraphs "0041" to "0054" of the same publication.

[0041] In one embodiment of the present invention, examples of monomers having carboxyl groups that constitute the copolymer include, for example, acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid, and salts thereof such as metal salts, ammonium salts, and organic amine salts.

[0042] In one embodiment of the present invention, the molar ratio of constituent units derived from monomers having sulfonic acid groups and constituent units derived from monomers having carboxyl groups in the anionic water-soluble polymer is preferably 1:99 to 99:1, and more preferably 5:95 to 95:5.

[0043] The weight-average molecular weight (Mw) of the anionic water-soluble polymer is preferably 1,500 or more, more preferably 3,000 or more, even more preferably 5,000 or more, even more preferably 7,000 or more, particularly preferably 8,000 or more, and most preferably 9,000 or more. Furthermore, the weight-average molecular weight of the anionic water-soluble polymer is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 100,000 or less, even more preferably 50,000 or less, particularly preferably 30,000 or less, and most preferably 15,000 or less. Specifically, the weight-average molecular weight of the anionic polymer is preferably 1,500 to 1,000,000, more preferably 3,000 to 500,000, even more preferably 5,000 to 100,000, even more preferably 7,000 to 50,000, particularly preferably 8,000 to 30,000, and most preferably 9,000 to 15,000. When the weight-average molecular weight of the anionic polymer is within the above range, the polishing speed of the object to be polished can be further reduced, and residue on the surface of the object to be polished can be removed more efficiently, thereby more effectively achieving the intended effects of the present invention.

[0044] In this specification, the weight-average molecular weight can be measured by gel permeation chromatography (GPC) using polyethylene glycol of known molecular weight as a reference substance, as described in the examples.

[0045] In one embodiment of the present invention, in the case of a polishing composition (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or polishing slurry) used as a polishing liquid for polishing an object, the content of the anionic water-soluble polymer is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.10% by mass or more, particularly preferably 0.15% by mass or more, and most preferably 0.20% by mass or more, based on the total mass of the polishing composition. In one embodiment of the present invention, the content of the anionic water-soluble polymer is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.50% by mass or less, and most preferably 0.45% by mass or less, based on the total mass of the polishing composition. In other words, the content of the anionic water-soluble polymer is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.05% by mass or more and 3.0% by mass or less, even more preferably 0.10% by mass or more and 1.0% by mass or less, particularly preferably 0.15% by mass or more and 0.50% by mass or less, and most preferably 0.20% by mass or more and 0.45% by mass or less.

[0046] Furthermore, in the case of polishing compositions used for polishing after dilution (i.e., concentrated liquids, working slurry stocks), the upper limit of the content of anionic water-soluble polymers is preferably 10% by mass or less, and more preferably 5% by mass or less, relative to the total mass of the polishing composition. The lower limit of the content of anionic water-soluble polymers is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more.

[0047] In one embodiment of the present invention, the anionic water-soluble polymer may be a block copolymer, a random copolymer, a graft copolymer, or an alternating copolymer. Furthermore, the anionic water-soluble polymer may be a commercially available product or a synthetic product. In addition, the anionic water-soluble polymer may be used alone or in combination of two or more types. When the polishing composition contains two or more types of anionic water-soluble polymers, the content of the anionic water-soluble polymers shall be their total amount.

[0048] (Polypropylene glycol) The polishing composition according to the present invention contains polypropylene glycol having a weight-average molecular weight of 200 to 700. In the polishing composition, the polypropylene glycol having a weight-average molecular weight of 200 to 700 is adsorbed onto the surface of the object to be polished (especially the polysilicon film) and moderately protects the surface from polishing by abrasive particles (anionically modified colloidal silica), thereby slowing down the polishing speed. Furthermore, the polypropylene glycol having a weight-average molecular weight of 200 to 700 easily detaches from the surface of the object to be polished (especially the polysilicon film), thus reducing the number of defects (residues) on the object to be polished. If the weight-average molecular weight of the polypropylene glycol is less than 200, it is undesirable because it cannot suppress the polishing speed of the surface of the object to be polished (especially the polysilicon film). Furthermore, if the weight-average molecular weight of the polypropylene glycol exceeds 700, the polypropylene glycol adsorbed onto the surface of the object to be polished becomes difficult to detach from the surface and tends to become a residue itself, which is undesirable.

[0049] Polypropylene glycol having a weight-average molecular weight of 200 to 700 may be used alone or in combination of two or more types. Furthermore, commercially available or synthetic polypropylene glycol having a weight-average molecular weight of 200 to 700 may be used.

[0050] Polypropylene glycol having a weight-average molecular weight of 200 to 700 is preferably 200 to 600, more preferably 200 to 500, even more preferably 200 to 450, and particularly preferably 250 to 450. Having the weight-average molecular weight of the polypropylene glycol within this range allows for a further reduction in the amount of residue.

[0051] In one embodiment of the present invention, in the case of an abrasive composition (typically a slurry-like abrasive, sometimes referred to as a working slurry or abrasive slurry) used as an abrasive liquid to polish an object to be polished, the lower limit of the content of polypropylene glycol having a weight-average molecular weight of 200 to 700 is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, particularly preferably 0.10% by mass or more, and most preferably 0.15% by mass or more, based on the total mass of the abrasive composition. Furthermore, the upper limit of the polypropylene glycol content is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.30% by mass or less, and most preferably 0.25% by mass or less, based on the total mass of the abrasive composition. Specifically, the polypropylene glycol content is preferably 0.01% to 5.0% by mass, more preferably 0.03% to 3.0% by mass, even more preferably 0.05% to 1.0% by mass, particularly preferably 0.10% to 0.30% by mass, and most preferably 0.15% to 0.25% by mass, relative to the total mass of the polishing composition. Within this range, the polishing speed of the surface of the object to be polished (especially the polysilicon film) can be sufficiently reduced, and the amount of residue on the surface can also be sufficiently reduced.

[0052] Furthermore, in the case of a polishing composition used for polishing after dilution (i.e., concentrated solution, working slurry stock), the upper limit of the content of polypropylene glycol having a weight-average molecular weight of 200 to 700 is preferably 10% by mass or less, and more preferably 5% by mass or less, relative to the total mass of the polishing composition. The lower limit of the content of polypropylene glycol having a weight-average molecular weight of 200 to 700 is preferably 0.05% by mass or more, and more preferably 0.10% by mass or more. Being within this range allows for a more sufficient reduction in the polishing speed of the surface of the object to be polished (especially the polysilicon film), and furthermore, a more sufficient reduction in the amount of residue on the surface.

[0053] (Nitrogen-free nonionic polymer) The polishing composition according to the present invention contains a nitrogen-free nonionic polymer other than polypropylene glycol, having a weight-average molecular weight of 200 to 700. The nitrogen-free nonionic polymer interacts with the nitrogen-containing nonionic polymer described later, thereby enhancing the intended effects of the present invention. Although the details of this mechanism are unclear, it is thought that hydrogen bonding occurs between the hydroxyl groups in the nitrogen-free nonionic polymer and the nitrogen element in the nitrogen-containing nonionic polymer, forming a strong hydrophilic film. This improves the hydrophilicity of the surface of the object to be polished (especially the polysilicon film), preventing residue from adhering to the surface or detached residue from re-adhering.

[0054] Examples of nitrogen-free nonionic polymers include any nonionic polymer that does not contain nitrogen atoms, such as polyvinyl alcohol, polyethylene glycol, polyvinyl ethers (polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, etc.), polyalkylene oxides (polyethylene oxide, polypropylene oxide, polybutylene oxide, etc.), water-soluble polysaccharides such as polyglycerin, polypropylene glycol, polybutylene glycol, hydroxyethylcellulose, alginic acid polyhydric alcohol esters, water-soluble urea resins, dextrin derivatives, and casein. Furthermore, not only polymers having the main chain structure described above, but also graft copolymers having a nonionic polymer structure in the side chain can be suitably used as nitrogen-free nonionic polymers. Nitrogen-free nonionic polymers may be polymers having identical (homopolymer) or different (copolymer) repeating structural units, and when the nitrogen-free nonionic polymer is a copolymer, the copolymer may take the form of a block copolymer, random copolymer, graft copolymer, or alternating copolymer.

[0055] The nitrogen-free nonionic polymer is preferably selected from the group consisting of polyvinyl alcohol, hydroxyethylcellulose, and polyglycerin, and more preferably polyvinyl alcohol. The nitrogen-free nonionic polymer may be used alone or in combination of two or more types. Furthermore, the nitrogen-free nonionic polymer may be a commercially available product or a synthesized product.

[0056] The weight-average molecular weight of the nitrogen-free nonionic polymer is preferably 1,500 or more, more preferably 2,000 or more, even more preferably 3,000 or more, even more preferably 4,500 or more, particularly preferably 5,500 or more, and most preferably 7,500 or more. Furthermore, the weight-average molecular weight of the nitrogen-free nonionic polymer is preferably 100,000 or less, more preferably 90,000 or less, even more preferably 70,000 or less, even more preferably 50,000 or less, particularly preferably 25,000 or less, and most preferably 20,000 or less. In other words, the weight-average molecular weight of the nitrogen-free nonionic polymer is preferably 1,500 to 100,000, more preferably 2,000 to 90,000, even more preferably 3,000 to 70,000, even more preferably 4,500 to 50,000, particularly preferably 5,500 to 25,000, and most preferably 7,500 to 20,000.

[0057] When the weight-average molecular weight of the nitrogen-free nonionic polymer is within the above range, the nitrogen-free nonionic polymer is more readily adsorbed onto the object to be polished (for example, a film containing polysilicon), allowing for more efficient removal of residue from the surface of the object after treatment with the polishing composition, thereby more effectively achieving the intended effects of the present invention.

[0058] In one embodiment of the present invention, in the case of a polishing composition used as is as a polishing liquid for polishing an object to be polished (typically a slurry-like polishing liquid, sometimes referred to as a working slurry or polishing slurry), the content of nitrogen-free nonionic polymer is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.005% by mass or more and 3% by mass or less, even more preferably 0.01% by mass or more and 1% by mass or less, and particularly preferably 0.05% by mass or more and 0.5% by mass or less, based on the total mass of the polishing composition. In the case of a polishing composition used after dilution for polishing (i.e., a concentrated liquid, a stock solution of working slurry), the content of nitrogen-free nonionic polymer is preferably 0.005% by mass or more and 25% by mass or less, more preferably 0.025% by mass or more and 15% by mass or less, based on the total mass of the polishing composition. If the polishing composition contains two or more types of nitrogen-free nonionic polymers, the content of nitrogen-free nonionic polymers is the sum of these amounts.

[0059] (Nitrogen-containing nonionic polymer) The polishing composition according to the present invention contains a nitrogen-containing nonionic polymer. As described above, the nitrogen-containing nonionic polymer interacts with a nitrogen-free nonionic polymer to contribute to the desired effects of the present invention. Furthermore, in the polishing composition according to the present invention, the nitrogen-containing nonionic polymer is adsorbed onto the surface of the object to be polished (particularly a film containing silicon dioxide), which slows down the polishing speed of the surface and can prevent the re-adhesion of residues (contaminants).

[0060] The weight-average molecular weight of the nitrogen-containing nonionic polymer is preferably 1,500 or more, more preferably 5,000 or more, even more preferably 9,000 or more, even more preferably 10,000 or more, particularly preferably 20,000 or more, and most preferably 40,000 or more. The weight-average molecular weight of the nitrogen-free nonionic polymer is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 300,000 or less, even more preferably 100,000 or less, particularly preferably 70,000 or less, and most preferably 50,000 or less. Specifically, the weight-average molecular weight of the nitrogen-free nonionic polymer is preferably 1,500 to 1,000,000, more preferably 5,000 to 500,000, even more preferably 9,000 to 300,000, even more preferably 10,000 to 100,000, particularly preferably 20,000 to 70,000, and most preferably 40,000 to 48,000. When the weight-average molecular weight of the nitrogen-free nonionic polymer is within the above range, the polishing speed on the object to be polished becomes slower, and residue on the surface of the object to be polished can be removed more efficiently.

[0061] The nitrogen-containing nonionic polymer can be any nonionic polymer having a nitrogen atom, such as polyamines, polyvinylpyrrolidone, polyacrylamide, poly-N-vinylacetamide, polydimethylacrylamide, polyacryloylmorpholine, poly-N-vinylcaprolactam, poly-N-isopropylacrylamide, and oxazoline group-containing polymers. Not only polymers having the main chain structure described above, but also graft copolymers having nonionic polymer structures in their side chains can be suitably used as nitrogen-containing nonionic polymers. The nitrogen-containing nonionic polymer may be a polymer having identical (homopolymer) or different (copolymer) repeating structural units, and when the nitrogen-containing nonionic polymer is a copolymer, the copolymer may take the form of a block copolymer, random copolymer, graft copolymer, or alternating copolymer.

[0062] The nitrogen-containing nonionic polymer is preferably a polymer having an amide group or an oxazoline group, more preferably one or more selected from the group consisting of polyvinylpyrrolidone, poly-N-vinylacetamide, polydimethylacrylamide, poly-N-vinylcaprolactam, poly-N-isopropylacrylamide, and oxazoline group-containing polymers, and even more preferably polyvinylpyrrolidone. With the above nitrogen-containing nonionic polymer, the polishing speed of the object to be polished (especially films containing silicon dioxide) can be made slower, and the residue on the surface of the object to be polished can be removed more efficiently. The nitrogen-containing nonionic polymer may be used alone or in combination of two or more types. Furthermore, the nitrogen-containing nonionic polymer may be a commercially available product or a synthetic product.

[0063] Furthermore, if the nitrogen-containing nonionic polymer is polyvinylpyrrolidone, it is preferable that the aforementioned nitrogen-free nonionic polymer is polyvinyl alcohol. By combining polyvinylpyrrolidone and polyvinyl alcohol, the polishing speed on the object to be polished (especially films containing silicon dioxide) can be made sufficiently slower, and the residue on the surface of the object to be polished can also be removed more effectively.

[0064] In one embodiment of the present invention, in the case of an abrasive composition used as is as an abrasive liquid for polishing an object to be polished (typically a slurry-like abrasive liquid, sometimes referred to as a working slurry or polishing slurry), the content of nitrogen-containing nonionic polymer is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.005% by mass or more and 3% by mass or less, even more preferably 0.01% by mass or more and 1% by mass or less, particularly preferably 0.01% by mass or more and 0.5% by mass or less, and most preferably 0.05% by mass or more and 0.5% by mass or less, based on the total mass of the abrasive composition. Furthermore, in the case of an abrasive composition used after dilution for polishing (i.e., a concentrated liquid, a stock solution of working slurry), the content of nitrogen-containing nonionic polymer is preferably 0.005% by mass or more and 25% by mass or less, based on the total mass of the abrasive composition, more preferably 0.025% by mass or more and 15% by mass or less. If an abrasive composition contains two or more nitrogen-containing nonionic polymers, the content of nitrogen-free nonionic polymers shall be the sum of these amounts.

[0065] The ratio of the weight-average molecular weight of the nitrogen-containing nonionic polymer to the weight-average molecular weight of the nitrogen-free nonionic polymer (nitrogen-containing nonionic polymer / nitrogen-free nonionic polymer) is preferably 0.1 to 50, more preferably 0.2 to 40, even more preferably 0.3 to 30, and particularly preferably 0.3 to 5.5. When the ratio of the weight-average molecular weight of the nitrogen-containing nonionic polymer to the weight-average molecular weight of the nitrogen-free nonionic polymer is within the above range, the nitrogen-free nonionic polymer and the nitrogen-containing nonionic polymer are more easily adsorbed onto the surface of the object to be polished (for example, a film containing silicon dioxide, a film containing polysilicon), the polishing speed of the surface can be slowed down, and the residue on the surface can be removed more efficiently, thus more effectively achieving the intended effects of the present invention.

[0066] (dispersion medium) The polishing composition according to the present invention contains a dispersion medium. The dispersion medium has the function of dispersing or dissolving each component. The dispersion medium preferably contains water, and more preferably contains only water. Alternatively, the dispersion medium may be a mixed solvent of water and an organic solvent for the dispersion or dissolution of each component. In this case, examples of organic solvents that can be used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, propylene glycol, and triethanolamine, which are organic solvents that are miscible with water. Alternatively, these organic solvents may be used without mixing with water to disperse or dissolve each component, and then mixed with water. These organic solvents can be used individually or in combination of two or more.

[0067] From the viewpoint of preventing contamination of the object to be polished and interference with the action of other components, water that contains as little residue as possible is preferable. For example, water with a total transition metal ion content of 100 ppb or less is preferable. Here, the purity of the water can be increased by operations such as removing residual ions using ion exchange resin, removing foreign matter by filtration, and distillation. Specifically, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, or distilled water.

[0068] (Other polymers) The polishing composition according to the present invention may further contain the above-mentioned anionic water-soluble polymer, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 to 700, and other polymers other than nitrogen-containing nonionic polymers. Cationic polymers and amphoteric polymers can be used as the other polymers. Furthermore, it is preferable that the other polymers are water-soluble polymers. Here, a water-soluble polymer refers to a water-soluble polymer having the same repeating structural units (homopolymer) or a water-soluble polymer having different repeating structural units (copolymer), and is typically a compound with a weight-average molecular weight (Mw) of 1000 or more.

[0069] Examples of cationic polymers include polyethyleneimine (PEI), polyvinylamine, polyallylamine, polyvinylpyridine, and polymers of cationic acrylamide.

[0070] Examples of amphoteric polymers include copolymers of vinyl monomers having anionic groups and vinyl monomers having cationic groups, and vinyl-based amphoteric polymers having carboxybetaine groups or sulfobetaine groups. Specifically, examples include acrylic acid / dimethylaminoethyl methacrylic acid copolymers and acrylic acid / diethylaminoethyl methacrylic acid copolymers.

[0071] (Surfactants) The polishing composition according to the present invention may further contain a surfactant. The type of surfactant is not particularly limited and may be any nonionic, anionic, cationic, or amphoteric surfactant.

[0072] Examples of nonionic surfactants include compounds other than the polypropylene glycol, nitrogen-free nonionic polymers, and nitrogen-containing nonionic polymers mentioned above. Examples include alkyl ether types such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; alkylphenyl ether types such as polyoxyethylene octylphenyl ether; alkyl ester types such as polyoxyethylene laurate; alkylamine types such as polyoxyethylene laurylamino ether; alkylamide types such as polyoxyethylene lauric acid amide; polypropylene glycol ether types such as polyoxyethylene polyoxypropylene ether; alkanolamide types such as oleic acid diethanolamide; and allylphenyl ether types such as polyoxyalkylene allylphenyl ether. In addition, propylene glycol, diethylene glycol, monoethanolamine, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylene glycol, alkanolamides, etc., can also be used as nonionic surfactants. Note that the nitrogen-free nonionic polymers and nitrogen-containing nonionic polymers mentioned above can function as nonionic surfactants, so it is not necessary to add a separate nonionic surfactant.

[0073] Examples of anionic surfactants include compounds other than the anionic water-soluble polymers mentioned above, such as carboxylic acid types like sodium myristate, sodium palmitate, sodium stearate, sodium laurate, and potassium laurate; sulfate ester types like sodium octyl sulfate; phosphate ester types like lauryl phosphate and sodium lauryl phosphate; and sulfonic acid types like sodium dioctyl sulfosuccinate and sodium dodecylbenzenesulfonate. Since the anionic polymers mentioned above can function as anionic surfactants, it is not necessary to add a separate anionic surfactant.

[0074] Examples of cationic surfactants include amines such as laurylamine hydrochloride; quaternary ammonium salts such as polyethoxyamine and lauryltrimethylammonium chloride; and pyridium salts such as laurylpyridinium chloride.

[0075] Examples of amphoteric surfactants include lecithin, alkylamine oxides, alkylbetaines such as N-alkyl-N,N-dimethylammonium betaine, and sulfobetaines.

[0076] Surfactants can be used individually or in combination of two or more types. Furthermore, commercially available surfactants or synthetic surfactants may be used.

[0077] In the case of an abrasive composition used directly as an abrasive liquid to polish an object (typically a slurry-like abrasive liquid, sometimes referred to as a working slurry or polishing slurry), the lower limit of the surfactant content is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more, based on 100% by mass of the total mass of the abrasive composition. The upper limit of the surfactant content is preferably 5% by mass or less, and more preferably 1% by mass or less, based on 100% by mass of the total mass of the abrasive composition. If the abrasive composition contains two or more surfactants, the surfactant content refers to the total amount of these surfactants.

[0078] <pH of the abrasive composition> The pH of the polishing composition according to one embodiment of the present invention is preferably 2.0 or more and less than 5.0. Having the pH of the polishing composition within this range allows for a slower polishing rate on the surface of the object to be polished (particularly an object containing silicon nitride), and further reduces the amount of residue on the surface.

[0079] The pH of the polishing composition according to one embodiment of the present invention is more preferably 2.0 to 4.5, even more preferably 2.0 to 4.0, even more preferably 2.0 to 3.5, particularly preferably 2.0 to 3.0, and most preferably 2.2 to 2.8. By having the pH of the polishing composition within this range, the polishing speed for the object to be polished (especially the object to be polished containing silicon nitride) becomes sufficiently slower, and the residue on the surface of the object to be polished can be reduced even more sufficiently.

[0080] (pH adjuster) The polishing composition according to the present invention may further contain a pH adjusting agent.

[0081] The pH adjusting agent is not particularly limited, and known pH adjusting agents used in the field of polishing compositions can be used, as can known acids, bases, or salts thereof other than the chelating agents mentioned above. Examples of pH adjusting agents include, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, lactic acid, malic acid, citric acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, melitic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and arginic acid. Examples include carboxylic acids such as pyric acid, fumaric acid, maleic acid, aconitic acid, amino acids, and anthranilic acid, as well as organic acids such as sulfonic acid and organic phosphonic acid; inorganic acids such as nitric acid, carbonic acid, hydrochloric acid, hypophosphorous acid, phosphorous acid, phosphonic acid, boric acid, and hydrofluoric acid; alkali metal hydroxides such as potassium hydroxide (KOH); alkali metal carbonates such as potassium carbonate (K2CO3) and sodium carbonate (Na2CO3); hydroxides of group 2 elements; ammonia (ammonium hydroxide); and organic bases such as quaternary ammonium hydroxide compounds.

[0082] pH adjusters can be used alone or in combination of two or more types.

[0083] The amount of pH adjuster in the polishing composition should be appropriately selected to achieve the desired pH value of the polishing composition.

[0084] The pH of the polishing composition shall be the value measured by the method described in the examples.

[0085] <Other ingredients> An abrasive composition according to one embodiment of the present invention may contain other components in any proportion as needed, as long as they do not hinder the effects of the present invention. However, it is desirable to avoid adding components other than the essential components of the abrasive composition according to one embodiment of the present invention as much as possible, as they may cause foreign matter (residue), so it is preferable that the amount of such additions be as small as possible. Examples of other components include antifungal agents (preservatives), reducing agents, oxidizing agents, etc. The abrasive composition according to the present invention is acidic. Furthermore, the abrasive composition according to the present invention contains polymers. For these reasons, it is preferable that the abrasive composition according to the present invention contains an antifungal agent (preservative). In other words, in one embodiment of the present invention, the polishing composition is substantially composed of an anionic water-soluble polymer, a copolymer comprising anionic-modified colloidal silica, water, a constituent unit having a sulfonic acid group or a salt thereof, and a constituent unit having a carboxyl group or a salt thereof, polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, and at least one selected from the group consisting of pH adjusters, organic solvents, and antifungal agents. In one embodiment of the present invention, the polishing composition is substantially composed of an anionic water-soluble polymer which is a copolymer containing anionic-modified colloidal silica, water, a structural unit having a sulfonic acid group or a salt thereof, and a structural unit having a carboxyl group or a salt thereof, polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, a pH adjuster, and at least one of an organic solvent and an antifungal agent.Here, "a copolymer comprising anionic water-soluble polymer, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, a pH adjuster, an organic solvent, and an antifungal agent, substantially composed of at least one selected from the group consisting of anionic water-soluble polymer, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 to 700, and a pH adjuster, an organic solvent, and an antifungal agent" and "a copolymer comprising anionic water-soluble polymer, polypropylene having a weight-average molecular weight of 200 to 700" "Substantially composed of polypropylene glycol, a nitrogen-free nonionic polymer other than polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, a pH adjuster, and at least one of an organic solvent and an antifungal agent" means that the total content of an anionic water-soluble polymer, which is a copolymer containing an anionic modified colloidal silica, water, a structural unit having a sulfonic acid group or a salt thereof, and a structural unit having a carboxyl group or a salt thereof, polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, a pH adjuster, an organic solvent, and an antifungal agent exceeds 99% by mass (upper limit: 100% by mass) of the polishing composition. Preferably, the polishing composition consists of an anionic water-soluble polymer, which is a copolymer containing anionic-modified colloidal silica, water, a structural unit having a sulfonic acid group or a salt thereof, and a structural unit having a carboxyl group or a salt thereof, polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol with a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, a pH adjuster, an organic solvent, and an antifungal agent (total content of the above = 100% by mass).

[0086] The antifungal agent (preservative) is not particularly limited and can be appropriately selected depending on the type of polymer. Specifically, examples include isothiazolinoline preservatives such as 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, and 1,2-benzoisothiazol-3(2H)-one (BIT), as well as phenoxyethanol.

[0087] Alternatively, the antifungal agent (preservative) may be a compound represented by the following chemical formula 1.

[0088] [ka]

[0089] In the above chemical formula 1, R 1 ~R 5 Each substituent is independently composed of a hydrogen atom, or at least two atoms selected from the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms.

[0090] Examples of substituents composed of at least two atoms selected from the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms include, for example, hydroxyl groups, carboxyl groups, alkyl groups having 1 to 20 carbon atoms, hydroxyalkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, hydroxyalkoxy groups having 1 to 20 carbon atoms, alkoxycarbonyl groups having 2 to 21 carbon atoms, aryl groups having 6 to 30 carbon atoms, aralkyl groups (arylalkyl groups) having 7 to 31 carbon atoms, aryloxy groups having 6 to 30 carbon atoms, aryloxycarbonyl groups having 6 to 30 carbon atoms, aralkyloxycarbonyl groups having 8 to 32 carbon atoms, acyl groups having 2 to 20 carbon atoms, and acyloxy groups having 2 to 20 carbon atoms.

[0091] More specifically, examples of alkyl groups having 1 to 20 carbon atoms include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; branched alkyl groups such as isopropyl, isobutyl, s-butyl, t-butyl, t-amyl, neopentyl, 3-methylpentyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-methyl-1-propylbutyl, 1,1-dipropylbutyl, 1,1-dimethyl-2-methylpropyl, and 1-methyl-1-isopropyl-2-methylpropyl groups; and cyclic alkyl groups such as cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and norbornenyl groups.

[0092] Examples of hydroxyalkyl groups having 1 to 20 carbon atoms include hydroxymethyl group, 2-hydroxyethyl group, 2-hydroxy-n-propyl group, 3-hydroxy-n-propyl group, 2-hydroxy-n-butyl group, 3-hydroxy-n-butyl group, 4-hydroxy-n-butyl group, 2-hydroxy-n-pentyl group, 3-hydroxy-n-pentyl group, 4-hydroxy-n-pentyl group, 5-hydroxy-n-pentyl group, 2-hydroxy-n-hexyl group, 3-hydroxy-n-hexyl group, 4-hydroxy-n-hexyl group, 5-hydroxy-n-hexyl group, and 6-hydroxy-n-hexyl group.

[0093] Examples of alkoxy groups with 1 to 20 carbon atoms include linear alkoxy groups such as methoxy, ethoxy, n-propyloxy, n-butyloxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, and n-decyloxy; isopropyloxy, isobutyloxy, s-butyloxy, t-butyloxy, t-amyloxy, neopentyloxy, 3-methylpentyloxy, and 1,1-diethyloxy. Examples include branched alkoxy groups such as propyloxy group, 1,1-dimethylbutyloxy group, 1-methyl-1-propylbutyloxy group, 1,1-dipropylbutyloxy group, 1,1-dimethyl-2-methylpropyloxy group, and 1-methyl-1-isopropyl-2-methylpropyloxy group; and cyclic alkoxy groups such as cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, and norbornenyloxy group.

[0094] Examples of hydroxyalkoxy groups having 1 to 20 carbon atoms include hydroxymethoxy group, 2-hydroxyethoxy group, 2-hydroxy-n-propyloxy group, 3-hydroxy-n-propyloxy group, 2-hydroxy-n-butyloxy group, 3-hydroxy-n-butyloxy group, 4-hydroxy-n-butyloxy group, 2-hydroxy-n-pentyloxy group, 3-hydroxy-n-pentyloxy group, 4-hydroxy-n-pentyloxy group, 5-hydroxy-n-pentyloxy group, 2-hydroxy-n-hexyloxy group, 3-hydroxy-n-hexyloxy group, 4-hydroxy-n-hexyloxy group, 5-hydroxy-n-hexyloxy group, and 6-hydroxy-n-hexyloxy group.

[0095] Examples of alkoxycarbonyl groups having 2 to 21 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, and decyloxycarbonyl group.

[0096] Examples of aryl groups with 6 to 30 carbon atoms include phenyl, naphthyl, anthranyl, and pyrenyl groups.

[0097] Examples of aralkyl groups (arylalkyl groups) having 7 to 31 carbon atoms include benzyl groups and phenethyl groups (phenylethyl groups), while examples of aryloxy groups having 6 to 30 carbon atoms include phenyloxy groups (phenoxy groups), naphthyloxy groups, anthranyloxy groups, and pyrenyloxy groups.

[0098] Examples of aryloxycarbonyl groups with 7 to 31 carbon atoms include phenyloxycarbonyl group, naphthyloxycarbonyl group, anthranyloxycarbonyl group, and pyrenyloxycarbonyl group.

[0099] Examples of aralkyloxycarbonyl groups with 8 to 32 carbon atoms include benzyloxycarbonyl groups and phenethyloxycarbonyl groups.

[0100] Examples of acyl groups with 1 to 20 carbon atoms include the methanol group (formyl group), ethanol group (acetyl group), propanoyl group, butanoyl group, pentanol group, hexanoyl group, octanoyl group, decanoyl group, and benzoyl group.

[0101] Examples of acyloxy groups with 1 to 20 carbon atoms include formyloxy, acetyloxy, propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, octanoyloxy, decanoyloxy, and benzoyloxy groups.

[0102] Furthermore, the antifungal agent represented by the above chemical formula 1 is preferably at least one selected from the group consisting of compounds represented by the following chemical formulas 1-a to 1-c.

[0103] [ka]

[0104] In the above chemical formulas 1-a to 1-c, R 1 ~R 3 Each substituent is independently composed of at least two atoms selected from the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms.

[0105] Examples of substituents composed of at least two atoms selected from the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms are the same as described above, and therefore will not be explained here.

[0106] More specific examples of compounds represented by the above chemical formula 1 include parahydroxybenzoic acid esters such as methyl parahydroxybenzoate, ethyl parahydroxybenzoate, butyl parahydroxybenzoate, and benzyl parahydroxybenzoate; salicylic acid, methyl salicylate, phenol, catechol, resorcinol, hydroquinone, isopropylphenol, cresol, thymol, phenoxyethanol, phenylphenol (2-phenylphenol, 3-phenylphenol, 4-phenylphenol), and 2-phenylethyl alcohol (phenethyl alcohol).

[0107] Among these, from the viewpoint of achieving the intended effects of the present invention more effectively, the compound represented by the above chemical formula 1 is preferably at least one selected from the group consisting of ethyl parahydroxybenzoate, butyl parahydroxybenzoate, and phenylphenol, with butyl parahydroxybenzoate being more preferred.

[0108] Alternatively, antifungal agents (preservatives) can be unsaturated fatty acids. Examples of unsaturated fatty acids include monounsaturated fatty acids such as crotonic acid, myristoleic acid, palmitoleic acid, oleic acid, and ricinoleic acid; diunsaturated fatty acids such as sorbic acid, linoleic acid, and eicosadienoic acid; triunsaturated fatty acids such as linolenic acid, pinolenic acid, and eleostearic acid; tetraunsaturated fatty acids such as stearidonic acid and arachidonic acid; pentaunsaturated fatty acids such as boseopentaenoic acid and eicosapentaenoic acid; and hexaunsaturated fatty acids such as docosahexaenoic acid and herringic acid.

[0109] Among these, sorbic acid is preferred as the unsaturated fatty acid from the viewpoint of achieving the intended effects of the present invention more effectively.

[0110] In addition to the above, 1,2-alkanediols such as 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol; alkylglyceryl ethers such as 2-ethylhexylglyceryl ether (ethylhexylglycerin); and compounds such as capric acid and dehydroacetic acid may be used as antifungal agents (preservatives).

[0111] The above-mentioned antifungal agents (preservatives) may be used individually or in combination of two or more types.

[0112] When an abrasive composition contains an antifungal agent (preservative), there is no particular lower limit to the amount (concentration) of the antifungal agent (preservative). In the case of an abrasive composition used as is as a polishing liquid to polish an object (typically a slurry-like polishing liquid, sometimes called a working slurry or polishing slurry), the amount is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.005% by mass or more, and particularly preferably 0.01% by mass or more, based on the total mass of the abrasive composition. Furthermore, there is no particular upper limit to the amount (concentration) of the antifungal agent (preservative) in an abrasive composition used as is as a polishing liquid to polish an object, but it is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less, based on the total mass of the abrasive composition. In other words, the content (concentration) of the antifungal agent (preservative) in the polishing composition is preferably 0.0001% to 5% by mass, more preferably 0.001% to 1% by mass, even more preferably 0.005% to 0.5% by mass, and particularly preferably 0.01% to 0.1% by mass, relative to the total mass of the polishing composition. Within this range, a sufficient effect for inactivating or destroying microorganisms can be obtained. If the polishing composition contains two or more antifungal agents (preservatives), the above content refers to the total amount of these agents.

[0113] <Method for producing abrasive compositions> The present invention provides a method for producing an abrasive composition, for example, by stirring and mixing anionic-modified colloidal silica, a dispersion medium, an anionic water-soluble polymer, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-containing nonionic polymer, and other components as needed. The temperature during mixing of each component is not particularly limited, but 10°C to 40°C is preferred, and heating may be used to increase the dissolution rate. The mixing time is also not particularly limited.

[0114] <Polishing method> Another embodiment of the present invention is a polishing method comprising the step of polishing an object to be polished using the above-mentioned polishing composition. With such a polishing method, the surface of the object to be polished can be polished gently while thoroughly removing any residue remaining on the surface.

[0115] The polishing composition according to the present invention is suitably used for polishing semiconductor substrates. Polishing methods for semiconductor substrates are broadly divided into a main (bulk) polishing step, which is performed to remove most of the material to be removed, and a finishing (buff) polishing step, which is performed to finish polishing the material. For example, in the main (bulk) polishing step, which roughly polishes the surface of the semiconductor substrate, a polishing composition with high processing power (polishing power) is used, while in the finishing (buff) polishing step, which polishes more delicately, a polishing composition with low polishing power tends to be used. In one embodiment, the polishing composition of the present invention is suitably used in the finishing (buff) polishing step of a semiconductor substrate.

[0116] As a polishing apparatus, a general polishing apparatus can be used that has a holder for holding a substrate or the like with the object to be polished, a motor with adjustable rotation speed, and a polishing platen to which a polishing pad (abrasive cloth) can be attached.

[0117] As the polishing pad, general nonwoven fabrics, polyurethanes, and porous fluororesins can be used without any particular restrictions. Preferably, the polishing pad has grooves that allow the polishing liquid to accumulate.

[0118] In this embodiment, the pressure between the workpiece to be polished and the pad during the polishing process (especially the finish polishing process) is preferably 0.3 psi (2.07 kPa) or more and 3 psi (20.7 kPa) or less, and more preferably 0.6 psi (4.14 kPa) or more and 2 psi (13.8 kPa) or less. Also, in this embodiment, the rotational speed of the head (carrier) during the polishing process is 50 rpm (0.83 s). -1 ) or more 100rpm(1.67s -1Preferably, it is less than or equal to 50 rpm (0.83 s). In this embodiment, the rotation speed of the surface plate in the polishing process is 50 rpm (0.83 s). -1 ) Above 100rpm (0.83s -1 It is preferable that the amount is less than or equal to the amount of polishing solution used in the polishing process. There are no restrictions on the amount of polishing solution supplied in the polishing process, but it is preferable that the surface of the object to be polished is covered with the polishing composition, for example, 50 to 300 ml / min is preferable. There are also no particular restrictions on the polishing time, but it is preferable that it is 5 to 60 seconds.

[0119] The method of supplying the polishing composition to the polishing pad is not particularly limited; for example, a method of continuous supply using a pump or the like can be employed. There is no limit to the amount supplied, but it is preferable that the surface of the polishing pad is always covered with the polishing composition according to the present invention.

[0120] After polishing is complete, the substrate is washed with running water, and any water droplets adhering to the substrate are removed using a spin dryer or the like to dry it, thereby obtaining a polished object.

[0121] The polishing composition according to the present invention may be a one-component type or a multi-component type, including a two-component type.

[0122] <Manufacturing method for semiconductor substrates> A polishing method according to one embodiment of the present invention is preferably used when the object to be polished is a semiconductor substrate. That is, according to another embodiment of the present invention, a method for manufacturing a semiconductor substrate is also provided, which includes polishing the semiconductor substrate by the above-described polishing method, where the object to be polished is a semiconductor substrate. Accordingly, according to the present invention, a method for manufacturing a semiconductor substrate is provided, which includes the step of polishing the object to be polished using a polishing composition comprising an anionic water-soluble polymer which is a copolymer containing anionic-modified colloidal silica, a dispersion medium, a constituent unit having a sulfonic acid group or a salt thereof, a constituent unit having a carboxyl group or a salt thereof, polypropylene glycol having a weight-average molecular weight of 200 to 700, a nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 to 700, and a nitrogen-containing nonionic polymer. Details of the semiconductor substrate to which this manufacturing method is applied are as described in the description of the object to be polished with the above-described polishing composition. In this manufacturing method, other steps can be appropriately adopted from known methods for manufacturing semiconductor substrates. [Examples]

[0123] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively. In addition, in the following examples, unless otherwise specified, the operations were carried out under conditions of room temperature (25°C) and relative humidity of 40%RH to 50%RH.

[0124] [Preparation of abrasive grains] As anion-modified colloidal silica, sulfonic acid-modified colloidal silica (prepared using the method described in “Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003), with an average primary particle size of 32 nm, an average secondary particle size of 69 nm, and an average degree of association of 2.2) was prepared.

[0125] The average primary particle diameter of anion-modified colloidal silica particles was calculated from the specific surface area of ​​the silica particles and the density of the silica particles, measured using the BET method with a "Flow Sorb II 2300" manufactured by Micromerities. The average secondary particle diameter of the anion-modified colloidal silica particles was measured using a dynamic light scattering particle size / grain size distribution device UPA-UTI151 manufactured by Nikkiso Co., Ltd. The average aggregate degree of the abrasive grains was calculated by dividing the average secondary particle diameter of the abrasive grains by the average primary particle diameter of the abrasive grains.

[0126] [Preparation of polymers] The following anionic water-soluble polymers, additives, nitrogen-free nonionic polymers, and nitrogen-containing nonionic polymers were prepared.

[0127] "Anionic water-soluble polymer" • Sodium salt of a copolymer of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid (hereinafter referred to as "(acrylic acid / sulfonic acid) copolymer") (Product name: Aron A-6012 (Toagosei Co., Ltd.)); weight-average molecular weight 10,000

[0128] "Additives" • Polypropylene glycol Newport (registered trademark) PP-200 (Sanyo Chemical Industries, Ltd.): Number average molecular weight 200 Polypropylene glycol 400 (Fujifilm Wako Pure Chemical Corporation): Weight-average molecular weight 400 Polypropylene glycol 700 (Fujifilm Wako Pure Chemical Corporation): Weight-average molecular weight 700 Polypropylene glycol 1000 (Fujifilm Wako Pure Chemical Industries, Ltd.): Weight-average molecular weight 1000 Polypropylene glycol 2000 (Fujifilm Wako Pure Chemical Corporation): Weight-average molecular weight 2000 • Polyethylene glycol PEG200 (Daiichi Kogyo Seiyaku Co., Ltd.): Weight-average molecular weight 200 PEG600 (Daiichi Kogyo Seiyaku Co., Ltd.): Weight-average molecular weight 600 Polyethylene glycol 1000 (Fujifilm Wako Pure Chemical Corporation): Weight-average molecular weight 1000 Polyethylene glycol 2000 (Fujifilm Wako Pure Chemical Corporation): Weight-average molecular weight 2000

[0129] "Nitrogen-free nonionic polymer" • Polyvinyl alcohol JMR-3HH (Nippon Vinegar & Polyvinyl Acetate Co., Ltd.): Weight-average molecular weight 5,000 JMR-10HH (Nippon Vinegar & Polyvinyl Acetate Co., Ltd.): Weight-average molecular weight 10,000 JMR-170HH (Nippon Vinegar & Polyvinyl Acetate Co., Ltd.): Weight-average molecular weight 77,000 Denka Poval (registered trademark) K-05 (Denka Co., Ltd.): Weight-average molecular weight 22,000 Polyvinyl alcohol (Sigma-Aldrich Japan): Weight-average molecular weight 10,2000 • Hydroxyethylcellulose Hydroxyethylcellulose (Sigma-Aldrich Japan): Weight-average molecular weight 25,000 HEC CF-W (Sumitomo Seika Chemicals): Weight average molecular weight 1,200,000

[0130] "Nitrogen-containing nonionic polymer" • Polyvinylpyrrolidone Pitzcol (registered trademark) K30A (Daiichi Kogyo Seiyaku Co., Ltd.); weight-average molecular weight 45,000 Pitzcol (registered trademark) K17L (Daiichi Kogyo Seiyaku Co., Ltd.); weight-average molecular weight 9,000 • Poly-N-vinylacetamide PNVA GE191-107 (Showa Denko Corporation); weight-average molecular weight 50,000 PNVA GE191-104 (Showa Denko Corporation); weight-average molecular weight 300,000 • Polydimethylacrylamide Poly(N,N-dimethylacrylamide) (Sigma-Aldrich Japan); weight-average molecular weight 10,000 • Poly-N-isopropylacrylamide Poly(N-isopropylacrylamide) (Sigma-Aldrich Japan); weight-average molecular weight 40,000 • Poly-N-vinyl caprolactam Rubiscol (registered trademark) Plus (BASF Japan Ltd.); weight-average molecular weight 70,000 • Oxazoline group-containing polymer Epocross (registered trademark) WS-700 (Nippon Shokubai Co., Ltd.); weight-average molecular weight 40,000

[0131] The weight-average molecular weight (Mw) of the above polymers was measured by the following method.

[0132] [Measurement of weight-average molecular weight (Mw) of polymers] The weight-average molecular weight (Mw) of the polymer was determined using the value obtained by gel permeation chromatography (GPC) (converted to polyethylene glycol). The weight-average molecular weight was measured using the following apparatus and conditions: GPC equipment: Manufactured by Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII) Column: VP-ODS (manufactured by Shimadzu Corporation) Mobile phase A:MeOH B: 1% aqueous solution of acetic acid Flow rate: 1mL / min Detector: ELSD, temp. 40℃, Gain 8, N2GAS 350kPa Oven temperature: 40℃ Injection volume: 40μL.

[0133] [pH of abrasive composition] The pH of the polishing composition was determined using a glass electrode type hydrogen ion concentration indicator (Horiba, Ltd., Model: F-23). ​​After three-point calibration using standard buffers (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)), the glass electrode was placed in the polishing composition, and the pH value after stabilization for at least two minutes was taken as the pH value.

[0134] [Preparation of abrasive compositions] (Example 1) As abrasive particles, the anionically modified colloidal silica obtained above was added to pure water, which was used as a dispersion medium, at room temperature (25°C) to a concentration of 1% by mass. Furthermore, an antifungal agent (1,2-benzoisothiazole-3(2H)-one aqueous solution (product name: San-ai Back R-30); manufactured by San-ai Oil Co., Ltd.) was added to obtain a mixed solution with a final concentration of 0.3 g / kg.

[0135] To the resulting mixture, a (acrylic acid / sulfonic acid) copolymer with a weight-average molecular weight of 10,000 was added as an anionic water-soluble polymer; polypropylene glycol with a weight-average molecular weight of 400 was added as an additive; polyvinyl alcohol with a weight-average molecular weight of 10,000 was added as a nitrogen-free nonionic polymer; and polyvinylpyrrolidone with a weight-average molecular weight of 45,000 was added as a nitrogen-containing nonionic polymer; all of which were stirred and mixed at 25°C for 5 minutes. Subsequently, the mixture was adjusted to a pH of 2.5 using nitric acid to obtain the polishing composition of Example 1.

[0136] Here, the content of the (acrylic acid / sulfonic acid) copolymer was 0.25% by mass relative to the total mass of the polishing composition; the content of the polypropylene glycol was 0.20% by mass relative to the total mass of the polishing composition; the content of the polyvinyl alcohol was 0.10% by mass relative to the total mass of the polishing composition; and the content of the polyvinylpyrrolidone was 0.10% by mass relative to the total mass of the polishing composition.

[0137] (Examples 2-27, Comparative Examples 1-13) Polishing compositions for Examples 2-27 and Comparative Examples 1-13 were prepared in the same manner as in Example 1, except that the types and / or content of abrasive grains, anionic water-soluble polymers, additives, nitrogen-free nonionic polymers, and nitrogen-containing nonionic polymers were changed as shown in Table 1 below.

[0138] In Tables 1A-1C, "PPG" represents "polypropylene glycol," "PEG" represents "polyethylene glycol," "PVA" represents "polyvinyl alcohol," "HEC" represents "hydroxyethylcellulose," "PVP" represents "polyvinylpyrrolidone," "PNVA" represents "poly-N-vinylacetamide," "PDMA" represents "polydimethylacrylamide," "PNIPAM" represents "poly-N-isopropylacrylamide," and "PNVCL" represents "poly-N-vinylcaprolactam."

[0139] Furthermore, a "-" in Table 1 below indicates that the agent was not used. Comparative Example 1 is an example in which nitrogen-containing nonionic polymer was not used, while Comparative Examples 2-5 are examples in which nitrogen-free nonionic polymer was not used.

[0140] [Table 1A]

[0141] [Table 1B]

[0142] [Table 1C]

[0143] [Polishing test] The following materials were prepared for polishing: (1) a polycrystalline silicon wafer (300 mm, manufactured by Advance Materials Technology Co., Ltd.), (2) a silicon wafer with a 10,000 Å thick TEOS film formed on its surface (TEOS substrate) (300 mm, blanket wafer, manufactured by Advantech Co., Ltd.), and (3) a silicon wafer with a 2,500 Å thick SiN film formed on its surface (SiN substrate) (300 mm, blanket wafer, manufactured by Advantech Co., Ltd.).

[0144] The polycrystalline silicon wafers, TEOS substrates, and SiN substrates prepared as described above were polished using the polishing compositions prepared in Examples 1 to 27 and Comparative Examples 1 to 13, respectively, under the following conditions.

[0145] <Polishing equipment and polishing conditions> Polishing equipment: FREX300E manufactured by Ebara Corporation Polishing pad: Nitta DuPont Corporation, hard polyurethane pad IC1010 Conditioner (dresser): Nylon brush (A188, 3M) Polishing pressure: 2.0 psi (1 psi = 6894.76 Pa, the same applies below) Polishing plate rotation speed: 80 rpm Head rotation speed: 80 rpm Supply of polishing composition: flow-through Polishing composition supply amount: 200mL / min Polishing time: 30 seconds.

[0146] [evaluation] The polishing speed and the amount of residue were evaluated according to the following evaluation method.

[0147] (polishing speed) The polishing rate (angiotensin / min) was calculated using the following formula.

[0148]

number

[0149] The film thickness (Å) of the object to be polished before and after polishing was determined using an optical film thickness measuring instrument (ASET-f5x: manufactured by KLA-Tencor Co., Ltd.), and the polishing speed (polishing rate) (Å / min) was evaluated by dividing the difference in film thickness before and after polishing by the polishing time. The polishing speed with the polishing composition according to one embodiment of the present invention is preferably 5 (Å / min) or more and 50 (Å / min) or less, more preferably 10 (Å / min) or more and 40 (Å / min) or less, and even more preferably 10 (Å / min) or more and 30 (Å / min) or less. In Table 1 below, the polishing speeds for polysilicon (Poly-Si) substrates, TEOS substrates, and silicon nitride (SiN) substrates are shown in the "poly-Si", "TEOS", and "SiN" columns, respectively.

[0150] (Measuring the number of residues) Using the Surfscan® SP5 optical inspection machine manufactured by KLA-Tencor Co., Ltd., the number of residue particles on the surface of polished Poly-Si substrates, TEOS substrates, and SiN substrates was evaluated. Specifically, for the polished TEOS substrates, Poly-Si substrates, and SiN substrates, the number of particles with a diameter exceeding 70 nm was counted for the remaining portion after excluding a 5 mm wide portion from the outer edge of one side (the portion from 0 mm to 5 mm wide, with the outer edge set to 0 mm). For the Poly-Si substrates, the number of particles with a diameter exceeding 50 nm was counted for the TEOS substrates and SiN substrates. Subsequently, for the polished Poly-Si substrates, TEOS substrates, and SiN substrates, the number of abrasive particles and organic particles was measured by SEM observation using a Review SEM RS6000 manufactured by Hitachi High-Tech Corporation. First, 100 residue particles were sampled from the remaining portion after excluding the 5 mm wide portion from the outer edge of one side of the polished Poly-Si substrates, TEOS substrates, and SiN substrates using SEM observation. Next, the type of residue (abrasive grains or organic residue) was identified from the 100 sampled residues by visual SEM observation, and the number of each type of residue (abrasive grain residue (SiO2 residue) and organic residue (pad debris, polymers, etc.) was confirmed. The evaluation results are shown in Tables 2A and 2B below.

[0151] [Table 2A]

[0152] [Table 2B]

[0153] As is clear from Tables 2A and 2B above, the polishing compositions of Examples 1 to 27 were found to reduce the polishing speed of the surface of the object to be polished while also reducing the amount of residue on the surface, compared to the polishing compositions of Comparative Examples 1 to 13.

Claims

1. A polishing composition used for polishing an object to be polished, comprising at least one of polycrystalline silicon, silicon oxide, and silicon nitride, Anion-modified colloidal silica and Dispersion medium and An anionic water-soluble polymer is a copolymer comprising a structural unit having a sulfonic acid group or a salt thereof, and a structural unit having a carboxyl group or a salt thereof, Polypropylene glycol having a weight-average molecular weight of 200 or more and 700 or less, A nitrogen-free nonionic polymer other than polypropylene glycol having a weight-average molecular weight of 200 or more and 700 or less, It contains a nitrogen-containing nonionic polymer, A polishing composition wherein the nitrogen-free nonionic polymer has a hydroxyl group.

2. The abrasive composition according to claim 1, wherein the nitrogen-free nonionic polymer is selected from the group consisting of polyvinyl alcohol, hydroxyethylcellulose, and polyglycerin.

3. The polishing composition according to claim 1 or 2, wherein the nitrogen-containing nonionic polymer is one or more selected from the group consisting of polyvinylpyrrolidone, poly-N-vinylacetamide, polydimethylacrylamide, poly-N-isopropylacrylamide, poly-N-vinylcaprolactam, and oxazoline group-containing polymers.

4. The polishing composition according to any one of claims 1 to 3, wherein the nitrogen-free nonionic polymer is polyvinyl alcohol, and the nitrogen-containing nonionic polymer is polyvinylpyrrolidone.

5. The polishing composition according to any one of claims 1 to 4, wherein the weight-average molecular weight of the nitrogen-free nonionic polymer is 100,000 or less.

6. An abrasive composition according to any one of claims 1 to 5, wherein the pH is 2.0 or higher and less than 5.

0.

7. An abrasive composition according to any one of claims 1 to 6, further comprising an antifungal agent.

8. A polishing method comprising the step of polishing an object to be polished using the polishing composition described in any one of claims 1 to 7.

9. A method for manufacturing a semiconductor substrate, comprising polishing the semiconductor substrate by the polishing method described in claim 8.

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