KR20200115201A - Polishing composition - Google Patents

Abstract

The present invention relates to a novel polishing composition which contributes to improving the quality of a device and, more specifically, to a polishing composition used for polishing a polishing object, comprising: an abrasive grain made by immobilizing organic acids on a surface; a first water-soluble polymer having a sulfonic acid group or a group having salt thereof or a carboxyl group or a group having salt thereof; a second water-soluble polymer different from the first water-soluble polymer; a nonionic surfactant; and an aqueous carrier.

Description

Polishing composition {POLISHING COMPOSITION}

The present invention relates to a polishing composition.

Due to the high integration brought about by the miniaturization of the LSI manufacturing process, electronic devices including computers have achieved high performance such as miniaturization, multifunctionality, and high speed. In a new microfabrication technique accompanying such high integration of LSI, a chemical mechanical polishing (CMP) method is used. The CMP method is a technique frequently used for flattening an interlayer insulating film, forming a metal plug, and forming a buried wiring (damascene wiring) in an LSI manufacturing process, particularly a multilayer wiring forming process.

In the formation of a metal plug or a wiring in a semiconductor device, generally, a conductor layer containing a metal is formed on a silicon oxide film, a silicon nitride film, a polysilicon film, etc. in which a concave portion is formed, and then a part of the conductor layer is described above. This is done by removing by polishing until the film is exposed. This polishing step is largely divided into a main (bulk) polishing step for performing polishing to remove most of the object to be removed, and a buff polishing step for finishing polishing the object (for example, Patent Document 1).

Japanese Patent Application Publication No. 2004-273502

In recent years, thinning of the film is in progress, and in the process of performing only the bulk polishing process and the buff polishing process using a general polishing composition, the present inventors have found that the quality of the final device to be manufactured may not be sufficient. I knew. Therefore, the problem to be solved by the present invention is to provide a novel polishing composition that contributes to improving the quality of a device as a final product.

In order to solve the above problems, the present inventors have repeatedly conducted extensive research. As a result, a first water-soluble polymer having an abrasive grain formed by immobilizing an organic acid on the surface, a group having a sulfonic acid group or a salt thereof, or a carboxyl group or a group having a salt thereof, and a second water-soluble polymer different from the first water-soluble polymer It has been found that the above problems can be solved by providing a polishing composition used for polishing an object to be polished, comprising a nonionic surfactant and an aqueous carrier.

The polishing composition of the present invention contributes to improving the quality of the device as a final product.

Hereinafter, the present invention will be described. In addition, this invention is not limited only to the following embodiment. In addition, unless otherwise specified, operation and measurement of physical properties, etc. are measured under conditions of room temperature (20 to 25°C)/relative humidity of 40 to 50% RH.

The present invention relates to a first water-soluble polymer having an abrasive grain formed by immobilizing an organic acid on the surface, a group having a sulfonic acid group or a salt thereof, or a carboxyl group or a group having a salt thereof, a second water-soluble polymer different from the first water-soluble polymer, It is a polishing composition used for polishing an object to be polished, containing a nonionic surfactant and an aqueous carrier. Such a polishing composition contributes to improving the quality of a device as a final product.

[Device manufacturing process]

In one embodiment of the present invention, the device is a semiconductor device. In one embodiment of the present invention, a polishing object is formed on a substrate (eg, a silicon wafer). The object to be polished is, but not limited to, an object to be polished including, for example, a Si-based material such as a silicon-silicon bond, a nitrogen-silicon bond, or an oxygen-silicon bond. According to this embodiment, there is a technical effect that roughness can be eliminated by polishing in advance, and processing time and steps in subsequent processes can be reduced.

In the present embodiment, examples of the polishing object having a silicon-oxygen bond include a silicon oxide film, BD (black diamond: SiOCH), SiOC, FSG (fluorosilicate glass), HSQ (hydrogen silsesquioxane), CYCLOTENE, and SiLK. , MSQ (methylsilsesquioxane), and the like. Examples of the polishing object having a silicon-silicon bond include Si-based alloys such as polysilicon, amorphous silicon, single crystal silicon, n-type doped single crystal silicon, p-type doped single crystal silicon, phosphorus-doped polysilicon, boron-doped polysilicon, and SiGe. I can. Examples of the object to be polished having a silicon-nitrogen bond include a silicon nitride film and SiCN (silicon carbonitride).

According to another embodiment of the present invention, the object to be polished is carbon, DFR (Dry film resist = dry film resist), SiC, or the like.

In one embodiment of the present invention, the device manufacturing process includes a bulk polishing step and a buff polishing step. In one embodiment of the present invention, the device manufacturing process includes a preliminary polishing step, a bulk polishing step, and a buff polishing step. Before, after, or before and after these polishing processes, a film formation process of the object to be polished may be included. In this embodiment, by performing a preliminary polishing step prior to the bulk polishing step for removing most of the object to be polished, the influence on the final device due to the surface roughness of the substrate or the object to be polished can be minimized. I can. In addition, since the number of defects in the device can be significantly reduced, the reliability of the final product, the device, is improved. Further, by polishing in advance, the roughness can be eliminated, and the processing time and steps in the subsequent process can be reduced.

In one embodiment of the present invention, the film thickness of the object to be polished is not particularly limited. In one embodiment of the present invention, a method of forming a film of an object to be polished is not particularly limited, and known film forming techniques such as ALD, CVD, and PVD can be applied. Although it is preferable to use ALD in order to thin the film thickness of the object to be polished more efficiently, it is of course not limited thereto.

In one embodiment of the present invention, the polishing composition may be used for polishing an object to be polished in any step, but is preferably used for polishing in a preliminary polishing step. According to this embodiment, the influence on the final device due to the surface roughness can be minimized. In addition, since the number of defects in the device can be significantly reduced, the reliability of the final product, the device, is improved. Further, by polishing in advance, roughness can be eliminated, and processing time and steps in subsequent processes can be reduced. Accordingly, in an embodiment of the present invention, the semiconductor device manufacturing process includes a preliminary polishing step, a bulk polishing step, and a buff polishing step, and as a polishing composition in the preliminary polishing step, the implementation of the present invention A process for manufacturing a semiconductor device using a polishing composition according to the form is provided. According to this embodiment, the influence on the final device due to the surface roughness can be minimized. In addition, since the number of defects in the device can be significantly reduced, the reliability of the final product, the device, is improved. In one embodiment of the present invention, the composition of the polishing composition used in the preliminary polishing step, the bulk polishing step, and the buff polishing step may be different from each other. That is, the composition of the polishing composition in the preliminary polishing step, the composition of the polishing composition in the bulk polishing step, and the composition of the polishing composition in the buff polishing step may all be different.

[Polishing method]

In one embodiment of the present invention, a method of polishing an object to be polished is provided, which includes polishing the object to be polished using a polishing composition. According to this polishing method, the quality of the device as the final product is improved. In one embodiment of the present invention, for example, a method of performing rotational treatment while flowing a polishing composition by pressing a pad against an object to be polished using a polishing device may be mentioned.

As the polishing apparatus, a general polishing apparatus having a holder for holding an object to be polished or the like, a motor capable of changing the rotational speed, and the like, and a polishing plate on which a pad can be attached can be used. As the pad, a general nonwoven fabric, polyurethane, and porous fluororesin can be used without particular limitation.

In one embodiment of the present invention, it is preferable to appropriately set the polishing conditions in the preliminary polishing step, the bulk polishing step, and the buff polishing step.

In this embodiment, the upper limit of the pressure between the object to be polished and the pad in the preliminary polishing step is preferably less than 3 psi, more preferably less than 2 psi, still more preferably less than 1.6 psi, and even more preferably less than 1.5 psi. Do. In this embodiment, the lower limit of the pressure between the object to be polished and the pad in the preliminary polishing step is preferably 0.1 psi or more, more preferably 0.3 psi or more, and even more preferably 0.5 psi or more. In this embodiment, the upper limit of the rotation speed of the head (carrier) in the preliminary polishing step is preferably less than 120 rpm, more preferably less than 100 rpm, and still more preferably less than 80 rpm. In this embodiment, the lower limit of the head rotation speed in the preliminary polishing step is preferably 50 rpm or more, more preferably 60 rpm or more, and even more preferably 70 rpm or more. In the present embodiment, the upper limit of the rotation speed of the platen in the preliminary polishing step is preferably less than 120 rpm, more preferably less than 100 rpm, and still more preferably less than 90 rpm. In this embodiment, the lower limit of the rotation speed of the platen in the preliminary polishing step is preferably 50 rpm or more, more preferably 60 rpm or more, and even more preferably 70 rpm or more. Although there is no limitation on the amount of the flow-through type supplied in the preliminary polishing step, it is preferable that the surface of the object to be polished is covered with the polishing composition, and is, for example, 50 to 300 ml/min. Further, the polishing time is also not particularly limited, but it is preferably 5 to 60 seconds.

In the present embodiment, the upper limit of the pressure between the object to be polished and the pad in the bulk polishing step is preferably less than 10 psi, more preferably less than 7 psi, and still more preferably less than 5 psi. In the present embodiment, the lower limit of the pressure between the object to be polished and the pad in the bulk polishing step is preferably 1 psi or more, more preferably 1.5 psi or more, more preferably 1.6 psi or more, and even more preferably 2 psi or more. , More preferably 3psi or more. In this embodiment, the upper limit of the head rotation speed in the bulk polishing step is preferably less than 130 rpm, more preferably less than 120 rpm, and still more preferably less than 110 rpm. In the present embodiment, the lower limit of the head rotation speed in the bulk polishing step is preferably 80 rpm or more, more preferably 90 rpm or more, and still more preferably 100 rpm or more. In this embodiment, the upper limit of the rotational speed of the surface plate in the bulk polishing step is preferably less than 140 rpm, more preferably less than 130 rpm, and still more preferably less than 120 rpm. In the present embodiment, the lower limit of the rotation speed of the surface plate in the bulk polishing step is preferably 80 rpm or more, more preferably 90 rpm or more, and even more preferably 100 rpm or more. Although there is no limitation on the amount of flow-through type supplied in the bulk polishing process, it is preferable that the surface of the object to be polished is covered with the polishing composition, and is, for example, 50 to 300 ml/min. Further, the polishing time is also not particularly limited, but it is preferably 30 to 120 seconds.

In this embodiment, the upper limit of the pressure between the object to be polished and the pad in the buffing step is preferably less than 3 psi, more preferably less than 2 psi, still more preferably less than 1.6 psi, and even more preferably less than 1.5 psi. Do. In this embodiment, the lower limit of the pressure between the object to be polished and the pad in the buffing step is preferably 0.3 psi or more, more preferably 0.6 psi or more, and even more preferably 0.8 psi or more. In this embodiment, the upper limit of the head rotation speed in the buffing step is preferably less than 100 rpm, more preferably less than 90 rpm, and still more preferably less than 80 rpm. In the present embodiment, the lower limit of the head rotation speed in the buffing step is preferably 50 rpm or more, more preferably 60 rpm or more, and even more preferably 70 rpm or more. In the present embodiment, the upper limit of the rotation speed of the platen in the buffing step is preferably less than 120 rpm, more preferably less than 100 rpm, and still more preferably less than 90 rpm. In this embodiment, the lower limit of the rotational speed of the platen in the buffing step is preferably 60 rpm or more, more preferably 70 rpm or more, and even more preferably 80 rpm or more. Although there is no limitation on the amount of the flow-through type supplied in the buff polishing step, it is preferable that the surface of the object to be polished is covered with the polishing composition, and is, for example, 50 to 300 ml/min. Further, the polishing time is also not particularly limited, but it is preferably 5 to 60 seconds.

In one embodiment of the present invention, (pressure of the object to be polished and the pad in the preliminary polishing step) / (pressure of the object to be polished and the pad in the bulk polishing step) is preferably less than 1.0, more preferably 0.75 or less. And more preferably 0.5 or less. In one embodiment of the present invention, (pressure of the object to be polished and the pad in the preliminary polishing step) / (pressure of the object to be polished and the pad in the bulk polishing step) is preferably 0.15 or more, and more preferably 0.20 or more. And more preferably 0.25 or more.

In one embodiment of the present invention, (pressure of the object to be polished and the pad in the buffing step) / (pressure of the object to be polished and the pad in the bulk polishing step) is preferably less than 1.0, more preferably 0.75 or less. And more preferably 0.5 or less. In one embodiment of the present invention, (pressure of the object to be polished and the pad in the buff polishing step) / (pressure of the object to be polished and the pad in the bulk polishing step) is preferably 0.15 or more, more preferably 0.20 or more. And more preferably 0.2 or more.

In one embodiment of the present invention, (pressure of the object to be polished and the pad in the buffing step)/(pressure of the object to be polished and the pad in the preliminary polishing step) is preferably 3.0 or less, more preferably 2.5 or less. And more preferably 2.0 or less. In one embodiment of the present invention, (pressure of the object to be polished and the pad in the buff polishing step) / (pressure of the object to be polished and the pad in the preliminary polishing step) is preferably 0.1 or more, and more preferably 0.3 or more. And more preferably 0.5 or more.

In one embodiment of the present invention, a preliminary polishing step is performed before the bulk polishing step, and a buff polishing step is performed after the bulk polishing step. In one embodiment of the present invention, after the buffing step, at least one of a rinse polishing treatment and a washing treatment may be provided. In addition, as the rinsing composition or the cleaning composition, a conventionally known one can be suitably used.

[Polishing composition]

In one embodiment of the present invention, the polishing composition includes a first water-soluble polymer having an abrasive grain obtained by immobilizing an organic acid on a surface thereof, a sulfonic acid group or a group having a salt thereof, or a carboxyl group or a group having a salt thereof, and the first It contains a second water-soluble polymer different from the water-soluble polymer, a nonionic surfactant, and an aqueous carrier, and is used for polishing an object to be polished.

(Abrasive grain formed by immobilizing organic acids on the surface)

In one embodiment of the present invention, the polishing composition includes abrasive grains obtained by immobilizing an organic acid on the surface (in this specification, also simply referred to as “abrasive grains”). The abrasive grains contained in the polishing composition have an action of mechanically polishing the object to be polished.

In one embodiment of the present invention, as a specific example of the abrasive, particles containing metal oxides such as silica, alumina, zirconia, and titania may be mentioned. These abrasive grains may be used alone or in combination of two or more. In addition, as the abrasive grain, a commercial product may be used or a synthetic product may be used. Among these abrasive grains, silica is preferable, fumed silica and colloidal silica are more preferable, and colloidal silica is particularly preferable. Examples of the method for producing colloidal silica include a sodium silicate method and a sol-gel method, and colloidal silica produced by any of the production methods is preferably used as the abrasive of the present invention. However, colloidal silica produced by a sol-gel method that can be produced with high purity is preferred.

In one embodiment of the present invention, the abrasive grains are abrasive grains obtained by immobilizing an organic acid on the surface. If no abrasive grains obtained by immobilizing an organic acid on the surface are used, the desired effect of the present invention cannot be exhibited. In particular, when the pH of the polishing composition is adjusted to an acidic region, there is a fear that the surface roughness of the object to be polished deteriorates if the surface does not contain abrasive grains obtained by immobilizing an organic acid.

In one embodiment of the present invention, the organic acid is not particularly limited, but includes sulfonic acid, carboxylic acid, phosphoric acid, and the like, preferably sulfonic acid. In addition, in the silica having an organic acid immobilized on the surface, an acidic group (e.g., a sulfo group, a carboxyl group, a phosphoric acid group, etc.) derived from the above organic acid is fixed to the surface of the silica by a covalent bond (in some cases through a linker structure). There will be. Here, the linker structure means an arbitrary structure interposed between the surface of silica and an organic acid. Accordingly, silica having an organic acid immobilized thereon may be formed by directly fixing an acidic group derived from an organic acid on the surface of the silica by covalent bonds, or by being fixed by covalent bonds through a linker structure. The method of introducing these organic acids to the silica surface is not particularly limited, and in addition to the method of introducing a mercapto group or an alkyl group to the silica surface and then oxidizing it with a sulfonic acid or carboxylic acid, a protecting group is bonded to the organic acid group. There is a method of introducing into the silica surface in a state and then removing the protecting group.

As a specific synthesis method of silica having an organic acid fixed on the surface, if sulfonic acid, which is a kind of organic acid, is fixed on the surface of silica, for example, "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. This can be done by the method described in 246-247 (2003). Specifically, by coupling a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane to silica and oxidizing the thiol group with hydrogen peroxide, a silica having a sulfonic acid immobilized thereon can be obtained. The colloidal silica in which the sulfonic acid of the examples of the present invention is modified on the surface is also prepared in the same manner.

If it is to fix the carboxylic acid to the surface of silica, for example, "Novel Silane Coupling Agents Containing a Photo labile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel", Chemistry Letters, 3, 228-229 It can be performed by the method described in (2000). Specifically, by coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to silica and then irradiating with light, a silica having a carboxylic acid immobilized on the surface can be obtained.

In one embodiment of the present invention, the average primary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, still more preferably 20 nm or more, even more preferably 25 nm or more, and 30 It is even more preferable that it is nm or more. In the polishing composition of the embodiment of the present invention, the average primary particle diameter of the abrasive grains is preferably 60 nm or less, more preferably 50 nm or less, and still more preferably 40 nm or less. Since the abrasive grains have the above average primary particle diameter, there is an effect of reducing scratches, reducing defects, and improving a polishing rate. The average primary particle diameter in the present invention may employ a value measured by the method described in Examples.

In one embodiment of the present invention, the average secondary particle diameter of the abrasive grains 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, and 60 It is even more preferable that it is nm or more, and it is even more preferable that it is 65 nm or more. In one embodiment of the present invention, the average secondary particle diameter of the abrasive grains is preferably less than 100 nm, more preferably 90 nm or less, further preferably 80 nm or less, and even more preferably 75 nm or less. Since the abrasive grains have the above average secondary particle diameter, there is an effect of improving the polishing rate. As the average secondary particle diameter in the present invention, a value measured by the method described in Examples may be adopted. In addition, when the average secondary particle diameter of the abrasive grains is 100 nm or more, there is a concern that dispersion stability of the abrasive grains may decrease.

In one embodiment of the present invention, in the particle size distribution of the abrasive grains in the polishing composition obtained by laser diffraction scattering method, the particle diameter when the accumulated particle mass reaches 90% of the total particle mass from the particle side The lower limit of the ratio of D90 and the particle diameter D10 when it reaches 10% (in this specification, also simply referred to as ``D90/D10'') is preferably 1.3 or more, more preferably 1.4 or more, and even more preferably 1.5 or more. And more preferably 1.6 or more. By being such a lower limit, there is an effect that the polishing rate can be improved. In one embodiment of the present invention, the upper limit of D90/D10 is preferably 4.0 or less, more preferably 3.5 or less, still more preferably 3.0 or less, and even more preferably 2.0 or less.

In one embodiment of the present invention, the aspect ratio of the abrasive grains is preferably 1.05 or more, more preferably 1.10 or more, and still more preferably 1.15 or more. According to this embodiment, there is a technical effect of improving the polishing rate. In one embodiment of the present invention, the aspect ratio of the abrasive grains is preferably 5 or less, more preferably 2 or less, and even more preferably 1.5 or less. According to this embodiment, there is a technical effect of improving dispersion stability and reducing the number of defects. In addition, the method of measuring the aspect ratio of the abrasive is according to the method described in Examples.

In one embodiment of the present invention, in the polishing composition, from the viewpoint of improving the polishing rate or lowering the surface roughness after polishing, the content of the abrasive grains is preferably more than 0.001% by mass, more preferably 0.005% by mass or more. And it is still 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 more than 0.01% by mass, even more preferably 0.3% by mass or more It may be 0.8% by mass or more, 1.2% by mass or more, 2% by mass or more, 3% by mass or more, or 4% by mass or more. In one embodiment of the present invention, in the polishing composition, from the viewpoint of reducing scratches and reducing the number of defects, the content of the abrasive grains is preferably 30% by mass or less, more preferably 20% by mass or less, and 15% by mass. It is still more preferable that it is less than or equal to 10% by mass, even more preferably less than or equal to 10% by mass, even more preferably less than or equal to 7% by mass, and less than or equal to 5% by mass, less than or equal to 4% by mass, less than or equal to 3% by mass, or less than or equal to 2% by mass , 1 mass% or less, less than 1 mass %, 0.8 mass% or less, 0.7 mass% or less, or 0.6 mass% or less may be sufficient. In addition, in this specification, the description regarding the content of a certain substance, etc., when two or more types of the substance are contained, shall mean the total amount.

(First water soluble polymer)

In one embodiment of the present invention, the polishing composition contains a first water-soluble polymer. The first water-soluble polymer has a sulfonic acid group or a group having a salt thereof, or a carboxyl group or a group having a salt thereof.

In one embodiment of the present invention, the first water-soluble polymer has a benzene ring. In this embodiment, the benzene ring may be contained in the main chain of the first water-soluble polymer, or may be contained in the form of a pendant group.

In one embodiment of the present invention, the first water-soluble polymer may contain a hetero atom in at least one of its main chain and side chain, but from the viewpoint of effectively exerting the desired effect of the present invention, it is better not to contain a hetero atom. good. Moreover, as said hetero atom, at least 1 type of an oxygen atom, a nitrogen atom, and a sulfur atom is mentioned.

In one embodiment of the present invention, the first water-soluble polymer,

Equation (1):

Contain a structural unit represented by, R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are each independently a hydrogen atom, -COOR ¹² or -G, provided that R ¹⁰ and R ¹¹ are simultaneously hydrogen Does not become an atom, -G is a sulfonic acid group,

And, provided that * represents a bonding position, R ¹² , R ¹³ and R ¹⁵ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation, R ¹⁴ is , Is a bivalent group. By being such an embodiment, the desired effect of this invention can be exhibited efficiently. In addition, in this specification, * represents a bonding position.

In one embodiment of the present invention, the first water-soluble polymer may contain two or more kinds of other structural units represented by the formula (1).

Here, the alkyl group having 1 to 12 carbon atoms may be linear or branched. For example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group Sil group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, stearyl group, icosyl group, docosyl group, tetracosyl group, triacontyl group, isopropyl group, isobutyl group, tert-butyl group, isopene Tyl group, neopentyl group, tert-pentyl group, isoheptyl group, 2-ethylhexyl group, and isodecyl group are mentioned.

In addition, examples of the hydroxyalkyl group having 1 to 12 carbon atoms include those in which at least one hydrogen atom of the alkyl group having 1 to 12 carbon atoms is substituted with a hydroxyl group.

Further, examples of the divalent group include an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 24 carbon atoms, and the like. The alkylene group having 1 to 12 carbon atoms is a divalent substituent from which two hydrogens of the alkyl group having 1 to 12 carbon atoms are removed. Moreover, as a C6-C24 arylene group, a phenylene group, a naphthalene diyl group, etc. are suitable.

Moreover, as a counter cation, an ammonium ion, a sodium ion, etc. are mentioned.

In one embodiment of the present invention, R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -G, and -G is a sulfonic acid group, or,

And R ¹³ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation.

In one embodiment of the present invention, it represented by the formula (1), and the other constituent unit include two or more of them, a structural unit is the R ^9, a hydrogen atom or a methyl group, the R ¹⁰ and R ¹¹ at least One is COOR ¹² , R ¹² is represented by a hydrogen atom or a counter cation, one constitutional unit is R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -G, and -G Is, a sulfonic acid group, or,

And R ¹³ is represented by a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation.

In one embodiment of the present invention, R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are each -COOR ¹² and a hydrogen atom, and R ¹² is a hydrogen atom or a counter cation. In this case, particularly, the pH is preferably less than 7.0, and more preferably less than 5.0.

In one embodiment of the present invention, in the first water-soluble polymer, R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are each -COOR ¹² , a hydrogen atom, and R ¹² is a hydrogen atom or a counter A structural unit that is a cation; R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are both -COOR ¹² and R ¹² is a hydrogen atom or a counter cation. In this case, it may be in the form of an anhydride, but it is preferable that it is not in the form of an anhydride.

In one embodiment of the present invention, R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are both -COOR ¹² , and R ¹² is a hydrogen atom or a counter cation.

In one embodiment of the present invention, in the first water-soluble polymer, R ⁹ is a hydrogen atom or a methyl group, R ¹⁰ and R ¹¹ are each -COOR ¹² , a hydrogen atom, and R ¹² is a hydrogen atom or a counter A structural unit that is a cation; R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -COOR ¹² , and R ¹² is a structural unit in which a C 1 to C 12 alkyl group is included.

In one embodiment of the present invention, in the first water-soluble polymer, R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -COOR ¹² , and R ¹² is a hydrogen atom or a counter cation. Constituent units; R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -G, and -G is,

And R ¹⁴ is a divalent group, and R ¹⁵ includes a structural unit which is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation.

In one embodiment of the present invention, R ⁹ is a hydrogen atom or a methyl group, at least one of R ¹⁰ and R ¹¹ is -G, and -G is,

And R ¹⁴ is a divalent group, and R ¹⁵ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation.

In one embodiment of the present invention, the first water-soluble polymer is a copolymer of sulfonic acid and carboxylic acid (also referred to as "sulfonic acid/carboxylic acid copolymer"). The copolymer of sulfonic acid and carboxylic acid contains a structural unit derived from a monomer having a sulfonic acid group and a structural unit derived from a monomer having a carboxylic acid group.

In one embodiment of the present invention, examples of the monomer having a sulfonic acid group include, for example, polyalkylene glycol-based monomers (A) described in paragraphs "0019" to "0036" of JP 2015-168770 A, or The sulfonic acid group-containing monomer (C) and the like described in paragraphs "0041" to "0054" of the same publication can be mentioned.

In one embodiment of the present invention, examples of the monomer having a carboxylic acid group include, for example, acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid, and their metal salts, ammonium salts, and organic amines. And salts such as salts.

In one embodiment of the present invention, the molar ratio of the structural unit derived from the monomer having a sulfonic acid group and the structural unit derived from the monomer having a carboxylic acid group in the sulfonic acid/carboxylic acid copolymer is the structural unit derived from the monomer having a sulfonic acid group: car Constituent units derived from monomers having an acid group = 5:95 to 95:5 are preferable, 10:90 to 90:10 are more preferable, 30:70 to 70:30 are still more preferable, and 45:55 to 65 :35 is more preferable, and 50:50 to 60:40 are most preferable.

In one embodiment of the present invention, the weight average molecular weight of the first water-soluble polymer is 1000 or more, 2000 or more, 3000 or more, from the viewpoint of the adsorption rate to the polishing object (i.e., easy adsorption to the polishing object), 4000 or more, 5000 or more, 6000 or more, 6500 or more, 7000 or more, 8000 or more, 9000 or more, 9500 or more, 10,000 or more, 15,000 or more, or 15,000 or more. In one embodiment of the present invention, the weight average molecular weight of the first water-soluble polymer is 100,000 or less, 30,000 or less, and 25,000 or less in terms of the rate of release from the object to be polished (easily detached from the object to be polished later). Or less, 20,000 or less, 15,000 or less, 10,000 or less, 9500 or less, 9000 or less, 8000 or less, 7000 or less, 6500 or less, or 6500 or less. In this embodiment, from the viewpoint of improving the polishing rate of the object to be polished containing nitrogen-silicon bonds and reducing the number of defects on the object to be polished containing oxygen-silicon bonds, the weight average molecular weight is more than 15,000. From the viewpoint of reducing the number of defects of the object to be polished including nitrogen-silicon bonds, the weight average molecular weight is preferably less than 6500, and the number of defects of the object to be polished containing silicon-silicon bonds is reduced. It is preferable that the weight average molecular weight is 650-15,000.

In addition, in this specification, the weight average molecular weight measures polystyrene of known molecular weight as a reference substance by gel permeation chromatography (GPC).

In one embodiment of the present invention, the content of the first water-soluble polymer is preferably 0.001% by mass or more, 0.005% by mass or more, 0.05% by mass or more, or 0.08% by mass or more with respect to the total mass of the polishing composition, It may be 0.2 mass% or more, 0.4 mass% or more, 0.6 mass% or more, and 0.8 mass% or more. In one embodiment of the present invention, the content of the first water-soluble polymer is 10 mass% or less, 8 mass% or less, 6 mass% or less, 4 mass% or less, 2 mass% or less, 1.9 mass% or less, 1.8 mass% Below, 1.7 mass% or less, 1.6 mass% or less, 1.5 mass% or less, 1.4 mass% or less, 1.3 mass% or less, 1.2 mass% or less, 1.1 mass% or less, 1.0 mass% or less, 0.9 mass% or less, 0.8 mass% It is 0.7 mass% or less, 0.6 mass% or less, 0.5 mass% or less, 0.4 mass% or less, 0.3 mass% or less, or 0.2 mass% or less. According to the embodiment of the present invention, even if the amount of the first water-soluble polymer is reduced, the effect of the present invention can be efficiently exhibited by the complementary cooperative action of the second water-soluble polymer and the nonionic surfactant.

In one embodiment of the present invention, the first water-soluble polymer may be a homopolymer or a copolymer. In the case of a copolymer, the form may be any of a block copolymer, a random copolymer, a graft copolymer, and an alternating copolymer.

In one embodiment of the present invention, the first water-soluble polymer is a polystyrene sulfonic acid, a (co)polymer including a structural unit derived from polystyrene sulfonic acid as part of the structure, a copolymer of a sulfonic acid and a carboxylic acid, a sulfonated polysulfone And at least one selected from the group consisting of polyanilic acid. By being such an embodiment, the desired effect of this invention can be exhibited efficiently.

(Second water soluble polymer)

In one embodiment of the present invention, the polishing composition contains a second water-soluble polymer different from the first water-soluble polymer. Here, it is added that the second water-soluble polymer may have a sulfonic acid group or a group having a salt thereof or a carboxyl group or a group having a salt thereof as long as it is different from the first water-soluble polymer.

In one embodiment of the present invention, the second water-soluble polymer is the following formula (2):

It includes a structural unit represented by, and X is, the following:

Appears as,

R ¹ to R ⁶ are each independently a hydrogen atom or -J, -J is a hydroxyl group, a sulfonic acid group or a group of a salt thereof,

, Provided that * represents a bonding position, R ⁷ and R ⁸ are each independently a hydrogen atom or -E, and -E is the following formula:

However, * represents a bonding position, and the said structural unit contains at least one of -J and -E. By being such an embodiment, the desired effect of this invention can be exhibited efficiently.

In one embodiment of the present invention, X is:

And at least one of R ¹ to R ⁴ is -J, and -J is a hydroxyl group, a sulfonic acid group or a group of a salt thereof, or

It is preferable to be.

In one embodiment of the present invention, X is:

And at least one of R ¹ to R ⁴ is -J, and -J is,

It is preferable to be.

In one embodiment of the present invention, X is:

And at least one of R ¹ , R ² , R ⁵ and R ⁶ is a hydrogen atom, R ⁸ is -E, and -E is the following formula:

It is preferable to appear as.

In one embodiment of the present invention, the weight average molecular weight of the second water-soluble polymer is 5,000 or more, 10,000 or more, 150,000 or more, 20,000 or more, or 250,000 or more from the viewpoint of reducing the number of scratches and defects. In one embodiment of the present invention, the weight average molecular weight of the second water-soluble polymer is 60,000 or less, 50,000 or less, 40,000 or less, 30,000 or less, 350,000 or less, 20,000 from the viewpoint of reducing the number of defects after polishing. It is less than 15,000, or less than 120,000. According to the embodiment of the present invention, even if the weight average molecular weight of the second water-soluble polymer is large, the effect of the present invention can be efficiently exhibited by the complementary cooperative action of the first water-soluble polymer and the nonionic surfactant.

In one embodiment of the present invention, when the second water-soluble polymer is a (co)polymer containing a structural unit derived from polyvinyl alcohol (PVA) or polyvinyl alcohol (PVA) as part of the structure, the weight average molecular weight The molecular weight of is less than 30000, 20000 or less, 15000 or less, and 12000 or less in preferred order. In addition, when the weight average molecular weight of the second water-soluble polymer is 15000 or less, in consideration of reducing the number of defects in SiN, polypropylene glycol is preferably used as the surfactant.

In one embodiment of the present invention, the content of the second water-soluble polymer is 0.001% by mass or more, 0.005% by mass or more, 0.05% by mass or more, 0.08% by mass or more, 0.2% by mass or more with respect to the total mass of the polishing composition. , 0.4% by mass or more, 0.6% by mass or more, or 0.8% by mass or more is preferable. By being such an embodiment, the desired effect of this invention is exhibited efficiently. In one embodiment of the present invention, the content of the second water-soluble polymer is 10 mass% or less, 8 mass% or less, 6 mass% or less, 4 mass% or less, 2 mass% or less, 1.9 mass% or less, 1.8 mass% It is 1.7 mass% or less, 1.6 mass% or less, 1.5 mass% or less, 1.4 mass% or less, 1.3 mass% or less, 1.2 mass% or less, or 1.1 mass% or less is preferable, and 0.8 mass% or less, 0.6 mass% or less , 0.4 mass% or less, or 0.3 mass% or less may be sufficient. According to an embodiment of the present invention, even if the amount of the second water-soluble polymer is reduced, in particular, the object to be polished containing an oxygen-silicon bond, nitrogen, due to the complementary cooperative action of the first water-soluble polymer and the nonionic surfactant. -For a polishing object containing a silicon bond, the effect of the present invention can be exhibited efficiently.

In one embodiment of the present invention, the second water-soluble polymer may be a homopolymer or a copolymer. In the case of a copolymer, the form may be any of a block copolymer, a random copolymer, a graft copolymer, and an alternating copolymer.

In one embodiment of the present invention, the second water-soluble polymer is a (co)polymer containing a structural unit derived from polyvinyl alcohol (PVA) and polyvinyl alcohol (PVA) as part of the structure, and polyN-vinylacetate. It is at least one member selected from the group consisting of amides and (co)polymers containing structural units derived from polyN-vinylacetamide as part of the structure. By being such an embodiment, the desired effect of this invention can be exhibited efficiently.

Further, in one embodiment of the present invention, the degree of saponification of the (co)polymer comprising a structural unit derived from the polyvinyl alcohol (PVA) or the polyvinyl alcohol (PVA) as part of the structure is preferably 90 % Or more.

In one embodiment of the present invention, at least one of the first water-soluble polymer and the second water-soluble polymer is a homopolymer. In particular, this embodiment has a technical effect of reducing defects in the silicon nitride film.

In one embodiment of the present invention, the second water-soluble polymer has a sulfonic acid group or a group having a salt thereof. Formation of a protective film by adsorbing the first water-soluble polymer and the second water-soluble polymer on the surface of the object to be polished by charge interaction, as the second water-soluble polymer as well as the first water-soluble polymer has a sulfonic acid group or a group having a salt thereof. Since the density can be further increased, the protective film can function like an easily peelable anti-adhesion film (in this specification, also simply referred to as a ``anti-adhesion film'') that prevents the substance causing the defect from adhering to the surface of the object to be polished. , The number of defects can be reduced.

(Ph of the polishing composition)

In one embodiment of the present invention, the polishing composition has a pH of less than 9.0. In one embodiment of the present invention, the polishing composition has a pH of less than 8.0. In one embodiment of the present invention, the polishing composition has a pH of less than 7.0. In one embodiment of the present invention, the polishing composition has a pH of less than 6.0. In one embodiment of the present invention, the polishing composition has a pH of less than 5.0. In one embodiment of the present invention, the polishing composition has a pH of less than 4.5. In one embodiment of the present invention, the polishing composition has a pH of less than 4.0. In one embodiment of the present invention, the polishing composition has a pH of 3.9 or less, a pH of 3.7 or less, a pH of 3.5 or less, or a pH of 3.3 or less. In one embodiment of the present invention, the polishing composition has a pH of more than 1.0. In one embodiment of the present invention, the polishing composition has a pH of more than 1.5. In one embodiment of the present invention, the polishing composition has a pH of more than 2.0. In one embodiment of the present invention, the polishing composition has a pH of 2.1 or higher. In one embodiment of the present invention, the polishing composition has a pH of 2.3 or higher. In one embodiment of the present invention, the polishing composition has a pH of 2.5 or more. In one embodiment of the present invention, the polishing composition has a pH of 2.7 or higher. In one embodiment of the present invention, the polishing composition has a pH of more than 2.0 and less than 5.0, and further, more than 2.0 and less than 4.0. According to this embodiment, the desired effect of the present invention can be exhibited efficiently.

In one embodiment of the present invention, the polishing composition contains a pH adjuster. As such a pH adjuster, known acids, bases, or salts thereof can be used. Specific examples of the acid that can be used as the pH adjuster include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid and phosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, 2- Methylbutyric acid, hexanoic acid, 3,3-dimethyl-butyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, heptanoic acid, 2-methylhexanoic acid, octanoic acid, 2-ethylhexanoic acid, benzoic acid, hydroxy acetic acid, salicylic acid , Glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5- And organic acids such as furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, and phenoxyacetic acid. However, one of the features of the present invention is that the first water-soluble polymer having a sulfonic acid group or a group having a salt thereof or a carboxyl group or a group having a salt thereof is contained in the polishing composition. Therefore, according to one embodiment of the present invention, only the first water-soluble polymer is the acid as the pH adjuster. With such an embodiment, it is possible to promote the formation of a protective film by the first water-soluble polymer on the surface of the object to be polished by charge interaction, and the protective film prevents adhesion of the substance causing the defect to the surface of the object to be polished. Since it can function like an easy adhesion prevention film, the number of defects can be reduced.

Further, when the second water-soluble polymer has a sulfonic acid group or a group having a salt thereof, only the first water-soluble polymer and the second water-soluble polymer are acids as a pH adjuster. According to this embodiment, the formation of a protective film by the first water-soluble polymer and the second water-soluble polymer on the surface of the object to be polished can be promoted by charge interaction, and the protective film adheres to the surface of the object to be polished. The number of defects can be reduced because it can function like an easily peelable anti-adhesion film that prevents it from being formed. In the embodiment of the present invention, such an effect can be particularly exhibited for Si-based materials (specifically, all materials containing silicon elements such as silicon oxide, polycrystalline silicon, and silicon nitride are shown) as an object to be polished.

Examples of bases that can be used as pH adjusters include amines such as aliphatic amines and aromatic amines, ammonium solutions, organic bases such as quaternary ammonium hydroxide, hydroxides of alkali metals such as potassium hydroxide, hydroxides of elements of Group 2, amino acids such as histidine. And ammonia. The pH adjuster may be used alone or in combination of two or more. The amount of the pH adjuster to be added is not particularly limited, and may be appropriately adjusted so that the polishing composition becomes a desired pH.

(Nonionic surfactant)

In one embodiment of the present invention, the polishing composition contains a nonionic surfactant.

In one embodiment of the present invention, the nonionic surfactant is a polymer, and its weight average molecular weight is preferably 50 or more, more preferably 100 or more, and even more preferably 200 or more. By being such an embodiment, the desired effect of this invention can be exhibited efficiently. In one embodiment of the present invention, the nonionic surfactant is a polymer, and its weight average molecular weight is preferably 10000 or less, more preferably 5000 or less, and even more preferably 1000 or less. By being such an embodiment, the desired effect of this invention can be exhibited efficiently.

In one embodiment of the present invention, the nonionic surfactant contains a glycerin structure and an alkyl group having 4 or more carbon atoms. In one embodiment of the present invention, the nonionic surfactant contains a glycerin structure and one alkyl group having 4 or more carbon atoms. In one embodiment of the present invention, the alkyl group preferably has 6 or more carbon atoms, more preferably 8 or more, and even more preferably 10 or more. By being such an embodiment, it can selectively adsorb on the surface of a Si-based material, and the desired effect of this invention is exhibited efficiently. In one embodiment of the present invention, the number of carbon atoms of the alkyl group is preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less. According to this embodiment, there is a technical effect of being adsorbed on the surface of the Si-based material and being easily removed later (for example, at the time of washing or rinsing).

In one embodiment of the present invention, the density of primary hydroxyl groups of the nonionic surfactant is 50% or more. To explain more clearly, of all the hydroxyl groups of a nonionic surfactant (for example, a polyglycerin surfactant), the primary hydroxyl group is 50% or more. When the density of primary hydroxyl groups of the nonionic surfactant is less than 50%, there is a fear that it is difficult to be adsorbed on the surface of the Si-based material. According to this embodiment, the primary hydroxyl group density is preferably 60% or more, more preferably 65% or more, still more preferably 70% or more, and even more preferably 75% or more. According to this embodiment, there is a technical effect of being easily adsorbed on the Si-based material surface. According to this embodiment, the primary hydroxyl group density is preferably 99% or less, more preferably 95% or less, still more preferably 92% or less, and even more preferably 90% or less.

The method of adjusting the primary hydroxyl group density of the nonionic surfactant to the above value is not particularly limited, and for example, a method disclosed in Japanese Patent Laid-Open No. 2006-346526 or the like may be applied. In addition, although this publication discloses polyglycerol lauryl ester, for knowledge of adjusting the primary hydroxyl group density to the above value, other polyol-based nonionic surfactants (for example, polyglycerol lauryl ether) It can also be applied to In addition, the ratio of a primary hydroxyl group and a secondary hydroxyl group can be calculated|required by spectrum analysis in a nuclear magnetic resonance apparatus as disclosed in "0018" of this document. In addition, by appropriately combining the techniques disclosed in Japanese Patent Application Publication No. 2013-181169, Japanese Patent Application Publication No. 2014-074175, Japanese Patent Application Publication No. 2019-026822, and Japanese Patent Application Publication No. 2011-007588. By reference, the density of primary hydroxyl groups can be adjusted to the above value.

In one embodiment of the present invention, the nonionic surfactant, as described above, is not a polyglycerin alkyl ether containing a glycerin structure and an alkyl group having 4 or more carbon atoms, but polypropylene glycol, polyglycerin, polyglycerin alkyl Esters, dextrins, dextrin derivatives, and the like, especially polypropylene glycol are also suitable.

In one embodiment of the present invention, the nonionic surfactant is polyglycerin alkyl ether, and its weight average molecular weight is 500 or more. When a polyglycerol alkyl ether having a weight average molecular weight of less than 500 is used, there is a fear that a film for preventing adhesion of a substance causing a defect may not be formed on the surface of an object to be polished. According to this embodiment, it is preferable that it is 750 or more, and, as for a weight average molecular weight, it is more preferable that it is 1250 or more, and it is still more preferable that it is 1500 or more. According to this embodiment, there is a technical effect that the adsorption rate at the time of formation of the film for preventing adhesion of the substance causing the defect is high, and it is easy to detach during washing or rinsing.

According to this embodiment, the weight average molecular weight may be 2500 or less. According to this embodiment, there is a technical effect of being able to form a film for preventing adhesion of substances causing defects by adsorbing to the surface of the object to be polished.

In one embodiment of the present invention, the polypropylene glycol may be a monool type, a diol type, a triol type, or a mixture of these. Among them, a diol type is preferable. The diol type is also used in Examples.

In addition, if polyethylene glycol (PEG) is used instead of polypropylene glycol (PPG), there is a concern that the surface roughness may deteriorate.

In one embodiment of the present invention, the weight average molecular weight of the polypropylene glycol is preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more. According to such an embodiment, the desired effect of this invention can be exhibited efficiently. According to an embodiment of the present invention, the weight average molecular weight of the polypropylene glycol is preferably 10000 or less, more preferably 5000 or less, and still more preferably 2000 or less. According to this embodiment, the solubility of polypropylene glycol is improved, and the desired effect of the present invention can be efficiently exhibited.

In one embodiment of the present invention, the content of the nonionic surfactant is 0.001% by mass or more, 0.005% by mass or more, 0.05% by mass or more, 0.08% by mass or more, and 0.2% by mass relative to the total mass of the polishing composition. It is preferable that it is 0.4 mass% or more, 0.6 mass% or more, or 0.8 mass% or more.

In one embodiment of the present invention, the content of the nonionic surfactant is 10% by mass or less, 8% by mass or less, 6% by mass or less, 4% by mass or less, 2% by mass or less, 1.9% by mass or less, and 1.8% by mass. It is preferable that they are less than or equal to 1.7 mass%, less than 1.6 mass%, 1.5 mass% or less, 1.4 mass% or less, 1.3 mass% or less, 1.2 mass% or less, or 1.1 mass% or less. In this embodiment, when the said nonionic surfactant is polyglycerin alkyl ether, the polyglycerol alkyl ether is 0.6 mass% or more, or 0.8 mass% or more. Thereby, the number of defects of an object to be polished containing an oxygen-silicon bond or an object to be polished containing a silicon-silicon bond can be further reduced. In addition, about the upper limit, the above description applies.

In one embodiment of the present invention, the weight average molecular weight of the first water-soluble polymer, the second water-soluble polymer, and the nonionic surfactant is 3000 or more, respectively; More than 5000; 200, 300, 400, or 500 or more; to be. Since all of the three compounds contained in the polishing composition as in this embodiment are polymers having a molecular weight of the lower limit, it is easy to form a film for preventing adhesion of a substance causing a defect on an object to be polished, and the desired effect of the present invention. There is a technical effect of efficiently exerting. In the present embodiment, the above description applies to the upper limit of the weight average molecular weight of the first water-soluble polymer, the second water-soluble polymer, and the nonionic surfactant.

In one embodiment of the present invention, the nonionic surfactant is not an amine type nonionic surfactant.

(Aqueous carrier)

The polishing composition according to one embodiment of the present invention usually contains an aqueous carrier. The aqueous carrier has a function of dispersing or dissolving each component. It is more preferable that the aqueous carrier is only water. In addition, the aqueous carrier may be a mixed solvent of water and an organic solvent in order to disperse or dissolve each component.

Water is preferably water that does not contain impurities as much as possible from the viewpoint of inhibiting contamination of the object to be polished or the action of other components. For example, water in which the total content of transition metal ions is 100 ppb or less is preferable. Here, the purity of water can be increased by operations such as removal of impurity ions using an ion exchange resin, removal of foreign matters by a filter, and distillation. Specifically, it is preferable to use deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, or the like as water.

(Other additives)

The polishing composition according to one embodiment of the present invention may contain other additives in an arbitrary ratio, if necessary, within a range that does not impair the effects of the present invention. As another additive, a preservative, a dissolved gas, a reducing agent, an oxidizing agent, etc. are mentioned, for example.

In one embodiment of the present invention, the polishing composition does not contain at least one selected from the group consisting of polyethylene glycol, polyoxyethylene nonylphenyl ether, polyglycerin and polyoxyethylene lauryl sulfate.

In one embodiment of the present invention, the polishing composition does not contain polyvinyl acetal.

In one embodiment of the present invention, the polishing composition does not contain a polymer containing a structural unit derived from hydroxyethylacrylamide.

In one embodiment of the present invention, the polishing composition does not contain a modified polyvinyl alcohol-based polymer containing an alkyleneoxy group.

In one embodiment of the present invention, the polishing composition does not contain a polymer containing a structural unit derived from (meth)acrylic acid amide.

[Example]

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 only to the following examples. In addition, unless otherwise specified, "%" and "part" mean "mass%" and "mass part", respectively. In addition, in the following Examples, the operation was performed under the conditions of room temperature (25 degreeC)/relative humidity 40-50% RH, unless otherwise specified.

[Preparation of composition for polishing]

As shown in Table 1, abrasive grains (sulfonic acid-fixed colloidal silica; average primary particle diameter: 35 nm, average secondary particle diameter: 70 nm, D90/D10: 1.7, aspect ratio: 1.2); A first water-soluble polymer; A second water-soluble polymer; With surfactants; Liquid carrier (pure water); For some examples and comparative examples, ammonia was appropriately added and mixed with stirring so as to obtain the composition and pH shown in Table 1 to prepare each polishing composition (mixing temperature: about 25°C , Mixing time: about 10 minutes). In addition, the density of primary hydroxyl groups of the polyglycerol lauryl ether and the polyglycerol lauryl ester used in Examples and Comparative Examples were all 75% to 85%. In addition, the saponification degrees of polyvinyl alcohol and sulfonic acid-modified polyvinyl alcohol used in Examples and Comparative Examples were 100% and 99%, respectively.

[Average primary particle diameter of abrasive grains]

The average primary particle diameter of the abrasive grains was calculated from the specific surface area of the abrasive grains by the BET method and the density of the abrasive grains measured using "Flow SorbII 2300" manufactured by Micromerics.

[Average secondary particle diameter of abrasive grains]

The average secondary particle diameter of the abrasive grains was calculated by the dynamic light scattering method measured using "UPA-UT151" manufactured by Microtrac.

[Abrasive aspect ratio]

As the aspect ratio of the abrasive grains, 300 abrasive grain images measured by FE-SEM were randomly extracted, and the average value of the measured aspect ratio (long diameter/short diameter) was adopted.

[Ph of the composition for polishing]

The pH of the polishing composition is a glass electrode type hydrogen ion concentration indicator (model number: F-23 manufactured by Horiba Seisakusho Co., Ltd.), and a standard buffer solution (phthalate pH buffer solution pH: 4.01 (25°C), neutral phosphate pH After three-point calibration using the buffer solution pH: 6.86 (25°C), carbonate pH buffer solution pH: 10.01 (25°C)), the glass electrode was added to the polishing composition, and the value after 2 minutes or more was stabilized to determine I did. The results are shown in Table 1.

[Polishing test]

In each of the Examples and Comparative Examples, a silicon wafer (300 mm, blanket wafer) having a thickness of 1000 Å, a silicon nitride film of 1000 Å, and a polysilicon film having a thickness of 1000 Å was formed on the surface of the silicon wafer (300 mm, blanket wafer). (In the table, they are represented by SiO ₂ , SiN, and Poly-Si, respectively). In addition, the silicon oxide film is derived from TEOS (tetraethyl orthosilicate). A coupon obtained by cutting each object to be polished into 60 mm×60 mm chips was used as a test piece, and polished under the following conditions.

(Polishing device and polishing conditions)

Polishing device: Nippon Engis Co., Ltd. lapping machine EJ-380IN-CH

Polishing pressure: 1.5psi (=10.3kPa)

Pad: Nitta Haas Co., Ltd. rigid polyurethane pad IC1010

Grinding plate rotation speed: 83rpm

Carrier rotation speed 77rpm

Supply of polishing composition: flow through

Polishing composition supply amount: 200ml/min

Polishing time: 20 seconds.

(Measurement of grinding speed)

The thickness of the test piece (film thickness) before and after polishing was measured with an optical film thickness measuring device (ASET-f5x: manufactured by KLA Tencor). The difference in the thickness (film thickness) of the test piece before and after polishing was calculated, divided by the polishing time, and the unit was adjusted to calculate the polishing rate (Å/min). These results are shown in the table below. In addition, 1 Å = 0.1 nm.

(Measurement of the number of defects)

About the polished test piece, the number of defects of 0.13 micrometer or more was measured. For the measurement of the number of defects, a wafer defect inspection device SP-2 manufactured by KLA TENCOR was used. The measurement was performed on the remaining portions except for a portion having a width of 5 mm from the outer peripheral end of one surface of the polished test piece (a portion having a width of 0 mm to a width of 5 mm when the outer peripheral end is 0 mm). The smaller the number of defects, the smaller the number of scratches, roughness, and residues on the surface, and the smaller the disorder of the surface.

(Measurement of surface roughness)

For the polished test piece, the surface roughness (Ra) was measured using a scanning probe microscope (SPM). In addition, as Ra, NANO-NAVI2 manufactured by Hitachi High Technologies Co., Ltd. was used. SI-DF40P2 was used as the cantilever. The measurement was performed three times at a scanning frequency of 0.86 Hz, X: 512 pt, and Y: 512 pt, and these average values were taken as surface roughness (Ra). In addition, the scanning range of SPM is a square area of "2 mu m x 2 mu m".

[Table 1-1]

[Table 1-2]

[Table 1-3]

[Table 1-4]

[Table 1-5]

[Table 2-1]

[Table 2-2]

[Table 2-3]

Claims (19)

Abrasive grains made by immobilizing organic acids on the surface,
A first water-soluble polymer having a sulfonic acid group or a group having a salt thereof or a carboxyl group or a group having a salt thereof,
A second water-soluble polymer different from the first water-soluble polymer,
A nonionic surfactant,
Aqueous carrier
Containing, used for polishing of a polishing object, a polishing composition. The polishing composition according to claim 1, wherein the pH is less than 9.0. The polishing composition according to claim 2, wherein the pH is less than 7.0. The polishing composition according to claim 3, wherein the pH is less than 5.0. The polishing composition according to any one of claims 1 to 4, wherein the content of the abrasive grains is more than 0.01% by mass. The polishing composition according to any one of claims 1 to 5, wherein the average secondary particle diameter of the abrasive grains is less than 100 nm. The polishing composition according to any one of claims 1 to 6, wherein at least one of the first water-soluble polymer and the second water-soluble polymer is a homopolymer. The method according to any one of claims 1 to 7, wherein the first water-soluble polymer,
Equation (1):

It includes a structural unit represented by,
R ⁹ is a hydrogen atom or a methyl group,
R ¹⁰ and R ¹¹ are each independently a hydrogen atom, -COOR ¹² or -G, provided that R ¹⁰ and R ¹¹ do not simultaneously become a hydrogen atom,
-G is a sulfonic acid group,

And, provided that * represents a bonding position,
R ¹² , R ¹³ and R ¹⁵ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, or a counter cation,
R ¹⁴ is a divalent group, and a polishing composition. The method according to any one of claims 1 to 8, wherein the second water-soluble polymer is the following formula (2):

It includes a structural unit represented by,
X is, to:

Appears as,
R ¹ to R ⁶ are each independently a hydrogen atom or -J,
-J is a hydroxyl group, a sulfonic acid group or a group of a salt thereof,

Represented by, provided that * represents a bonding position,
R ⁷ and R ⁸ are each independently a hydrogen atom or -E,
-E is the following formula:

Is represented by, provided that * indicates a bonding position,
The composition for polishing, wherein the structural unit contains at least one of -J and -E. The (co)polymer according to any one of claims 1 to 9, wherein the first water-soluble polymer contains a structural unit derived from polystyrene sulfonic acid or polystyrene sulfonic acid as part of its structure, and a copolymer of sulfonic acid and carboxylic acid. , Sulfonated polysulfone, and at least one selected from the group consisting of polyanilic acid, a polishing composition. The (co)polymer according to any one of claims 1 to 10, wherein the second water-soluble polymer contains a structural unit derived from polyvinyl alcohol (PVA) and polyvinyl alcohol (PVA) as part of the structure, A polishing composition, which is at least one member selected from the group consisting of polyN-vinylacetamide and a (co)polymer containing constituent units derived from polyN-vinylacetamide in a part of the structure. The polishing composition according to claim 11, wherein the saponification degree of the (co)polymer comprising a structural unit derived from the polyvinyl alcohol (PVA) or the polyvinyl alcohol (PVA) is 90% or more. The polishing composition according to claim 1, wherein the second water-soluble polymer has a group having a sulfonic acid group or a salt thereof. The polishing composition according to any one of claims 1 to 13, wherein the nonionic surfactant is polypropylene glycol. The polishing composition according to any one of claims 1 to 14, which is used for preliminary polishing. The polishing composition according to any one of claims 1 to 15, wherein the object to be polished contains a silicon-silicon bond, a nitrogen-silicon bond, or an oxygen-silicon bond. The polishing according to any one of claims 1 to 16, wherein the weight average molecular weight of the first water-soluble polymer, the second water-soluble polymer, and the nonionic surfactant is 3000 or more, 5000 or more, and 200 or more, respectively. Composition. A method of polishing an object to be polished, comprising polishing the object to be polished using the polishing composition according to any one of claims 1 to 17. A semiconductor device manufacturing process, including a preliminary polishing step, a bulk polishing step, and a buff polishing step, as a polishing composition in the preliminary polishing step, the polishing according to any one of claims 1 to 18. A process for manufacturing a semiconductor device using the composition.