JP2022056348A - Polishing composition and manufacturing method thereof, polishing method, and substrate manufacturing method - Google Patents

Abstract

To provide means capable of achieving a remarkably high selectivity and a remarkably high step reduction effect between different materials while achieving a high polishing rate for a specific material.SOLUTION: A polishing composition according to the present invention includes silica with organic acid fixed on the surface and polyalkylene glycol, and the polyethylene glycol-equivalent molecular weight distribution of polyalkylene glycol by gel permeation chromatography (GPC) has two or more peaks within a predetermined molecular weight range, at least one of which is a peak derived from polyethylene glycol, and pH is 3 or more and 6 or less.SELECTED DRAWING: None

Description

The present invention relates to a polishing composition, a method for producing the same, a polishing method, and a method for producing a substrate.

In the semiconductor device manufacturing process, as the performance of semiconductor devices is improved, a technique for manufacturing wiring with higher density and higher integration is required. CMP (Chemical Mechanical Polishing) has become an indispensable process in the manufacturing process of such a semiconductor device. As the miniaturization of semiconductor circuits progresses, the flatness required for the unevenness of pattern wafers increases, and it is required to realize high flatness on the nano-order by CMP. In order to achieve high smoothness by CMP, it is preferable to polish the convex portion of the pattern wafer at a high polishing rate while not polishing the concave portion very much.

Semiconductor wafers are composed of dissimilar materials such as polycrystalline silicon that forms circuits, silicon oxide that is an insulating material, and silicon nitride that protects the surface of silicon dioxide that is not part of a trench or via from damage during etching. To. For this reason, there is a problem that a step remains due to a phenomenon such as dishing in which a certain material is excessively ground as compared with other materials due to a difference in the polishing speed of each material depending on the polishing composition. For these reasons, it is required to sufficiently eliminate the step in the pattern wafer polishing process.

As a technique for meeting this demand, for example, Patent Document 1 discloses a polishing composition capable of polishing a polishing object having poor chemical reactivity such as silicon nitride at a higher speed than that of polycrystalline silicon or the like. ing. Specifically, as such a polishing composition, a polishing composition containing colloidal silica on which an organic acid is immobilized and having a pH of 6 or less is disclosed.

Further, for example, Patent Document 2 describes that while maintaining or improving the polishing rate of silicon nitride or the like, the polishing rate of polycrystalline silicon, silicon oxide or the like is suppressed, the dishing phenomenon is suppressed, and the step is reduced. Possible polishing compositions are disclosed. Specifically, as such a polishing composition, a silica having an organic acid immobilized on the surface and a polyoxyalkylene group-containing compound are contained, and gel permeation chromatography (gel permeation chromatography) for the polyoxyalkylene group-containing compound ( A polishing composition is disclosed in which the molecular weight distribution of the weight average molecular weight (polyethylene glycol equivalent) according to GPC) has two or more peaks and the pH is 7 or less.

Japanese Unexamined Patent Publication No. 2012-040671 International Publication No. 2016/052281

However, in recent years, while the performance required for semiconductor devices and the like has improved, further improvement in polishing performance by the polishing composition is expected. For example, it shows a higher selectivity between different materials than the polishing compositions described in Patent Documents 1 and 2, and further reduces the step when the polishing composition containing different materials is polished. A polishing composition showing an effect is expected.

Therefore, an object of the present invention is to provide a means capable of realizing a remarkably high selection ratio and a remarkably high step reduction effect between different materials while realizing a high polishing rate for a specific material.

The above problems of the present invention can be solved by the following means:
Silica with organic acid fixed on the surface and
With polyalkylene glycol
Contains,
The molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC) for the polyalkylene glycol has two or more peaks.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 100 or more and 800 or less.
The polyalkylene glycol contains polyethylene glycol and
At least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol.
A polishing composition having a pH of 3 or more and 6 or less.

The above-mentioned problems of the present invention can also be solved by the following means:
Silica with organic acid fixed on the surface and
With polyalkylene glycol
Has a mixing step to mix
The molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC) for the polyalkylene glycol has two or more peaks.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 100 or more and 800 or less.
The polyalkylene glycol contains polyethylene glycol, and at least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol.
A method for producing a polishing composition, which has a pH of 3 or more and 6 or less.

The above-mentioned problems of the present invention can also be solved by the following means:
Silica with organic acid fixed on the surface and
In the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC), polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less,
In the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC), polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less,
Have a mixing step of mixing,
A method for producing a polishing composition, which has a pH of 3 or more and 6 or less.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a means capable of realizing a remarkably high selection ratio and a remarkably high step reduction effect between different materials while realizing a high polishing rate for a specific material.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. Further, in the present specification, "XY" indicating a range means "X or more and Y or less". Unless otherwise specified, operations and measurements of physical properties are carried out under the conditions of room temperature (range of 20 ° C. or higher and 25 ° C. or lower) / relative humidity of 40% RH or higher and 50% RH or lower.

<Polishing composition>
One aspect of the present invention contains silica having an organic acid immobilized on the surface and polyalkylene glycol, and has two polyethylene glycol-equivalent molecular weight distributions of the polyalkylene glycol by gel permeation chromatography (GPC). At least one peak of the molecular weight distribution having the above peaks has a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution has a peak top molecular weight of 100 or more. The polyalkylene glycol has a peak of 800 or less, the polyalkylene glycol contains polyethylene glycol, and at least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol. The present invention relates to a composition for polishing having a pH of 3 or more and 6 or less.

According to such a polishing composition, it is possible to provide a means capable of achieving a remarkably high selection ratio and a remarkably high step reduction effect between different materials while achieving a high polishing rate for a specific material.

In particular, in one embodiment of the present invention, a material having a silicon-nitrogen bond such as silicon nitride, a material having a silicon-oxygen bond such as silicon oxide (SiN), and polycrystalline silicon (polysilicon, Poly-Si) and the like. The effects of the present invention are more pronounced in objects to be polished, including at least one of the silicon-silicon bonds of the above. More specifically, the polishing rate of the material having a silicon-nitrogen bond is further increased. In one embodiment of the present invention, the ratio of the polishing rate of a material having a silicon-nitrogen bond to the polishing rate of a material having a silicon-oxygen bond (selection ratio of a material having a silicon-nitrogen bond to a material having a silicon-oxygen bond). ), And the ratio of the polishing rate of the material having a silicon-nitrogen bond to the material having a silicon-silicon bond (selection ratio of the material having a silicon-nitrogen bond to the material having a silicon-silicon bond) is further increased. In one embodiment of the present invention, the effect of reducing the step difference of the object to be polished containing a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-oxygen bond such as silicon oxide is further enhanced. In one embodiment of the present invention, the effect of reducing the step difference of the object to be polished including a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-silicon bond such as polysilicon is further enhanced.

The detailed reason why the present invention can realize a remarkably high selection ratio and a remarkably high step reduction effect between different materials while achieving a high polishing rate for a specific material is unknown, but the following It is presumed to be due to the mechanism.

The zeta potential of silica with an organic acid fixed on the surface is negative and the absolute value is also large. In addition, some of the materials contained in the object to be polished have a positive zeta potential at a pH of 6 or less. Therefore, if the pH of the polishing composition is 6 or less, the silica in which the organic acid in the polishing composition is fixed on the surface and the material having a positive zeta potential in this pH range electrically repel each other. Rather, they will be attracted to each other. Further, silica having an organic acid immobilized on the surface has a functional group derived from an organic acid, which is a functional group other than the hydroxy group. This organic acid-derived functional group does not interact with the polyalkylene glycol, and the hydrophilicity inherent in silica is easily exhibited. Furthermore, under acidic conditions, the zeta potential of the silica with the organic acid fixed on the surface is large, so that electrical repulsion occurs between the silicas with the organic acid fixed on the surface, and the dispersion stability of the silica with the organic acid fixed on the surface occurs. Is improved. From these facts, in the polishing composition having a pH of 6 or less, by using silica having an organic acid fixed on the surface as abrasive grains, a high polishing rate can be obtained for a material having a positive zeta potential in this pH range. Will be done. Examples of the material having a positive zeta potential in the pH range of 6 or less include materials having a silicon-nitrogen bond such as silicon nitride.

Further, the polyalkylene glycol is adsorbed on the surface of the object to be polished by the action of hydrogen bonding or the like. The polyalkylene glycol acts to protect the surface of the object to be polished from the mechanical action of the abrasive grains. Here, the ease of adsorption of polyalkylene glycol changes depending on the type of the object to be polished. From this, it is possible to control the polishing speed by the polishing composition and the selection ratio between different materials by selecting the type of the polishing object, the type of the polyalkylene glycol in the polishing composition, the combination thereof, and the like. Become. Further, by including the polyalkylene glycol having two or more peaks in the molecular weight distribution in the polishing composition, the gap in which the component having a larger molecular weight is adsorbed is further adsorbed so that the component having a smaller molecular weight fills the gap. do. As a result, a dense protective film is formed on the surface of the object to be polished, and the effect of reducing the step is further improved.

Then, by setting the pH range of the polishing composition containing silica having an organic acid fixed on the surface and polyalkylene glycol to 3 or more and 6 or less, the selection ratio between different materials related to a specific combination of materials is set. For example, the selectivity of a material having a silicon-nitrogen bond to a material having a silicon-oxygen bond can be significantly improved.

However, in our studies, in such a pH range, the effect of suppressing the polishing rate on a specific material, for example, a material having a silicon-silicon bond such as polycrystalline silicon, is in another pH range. We have found that it may be less than that. This means that the effect of improving the selectivity between other dissimilar materials, for example, the selectivity of a material having a silicon-nitrogen bond such as silicon nitride with respect to a material having a silicon-silicon bond such as polycrystalline silicon, is other than that. It shows that it may be smaller than the pH range of.

Therefore, the present inventors further proceeded with the study. As a result, it was found that the polyalkylene glycol containing a specific component and having a specific molecular weight distribution eliminates the decrease in the effect of suppressing the polishing rate on a specific material in this pH range, and completes the present invention. rice field. That is, in the present invention, for polishing, which contains silica having an organic acid fixed on the surface and polyalkylene glycol containing a specific component and having a specific molecular weight distribution, and having a pH range of 3 or more and 6 or less. Use the composition. By using such a polishing composition, a remarkably high selection ratio and a remarkably high step reduction effect can be obtained among different materials having a wide range of combinations. The reason for this is that in this pH range, attractive force, repulsive force, adsorption, desorption, etc. are performed between each material contained in the polishing object, silica having an organic acid fixed on the surface in the polishing composition, and polyalkylene glycol. Is considered to be because is optimized. It is considered that these synergistic effects significantly improve the selection ratio between different materials and the effect of reducing the step.

The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

Hereinafter, each component that can be contained in the polishing composition, each raw material used for producing the polishing composition, the physical properties and characteristics of the polishing composition, the object to be polished, and the like will be described.

(Silica with organic acid fixed on the surface)
The polishing composition according to one embodiment of the present invention contains silica having an organic acid immobilized on the surface. Further, in the method for producing a polishing composition according to an embodiment of the present invention, silica having an organic acid fixed on the surface is used as a raw material. "Silica with an organic acid fixed on the surface" is silica used as an abrasive grain, in which an organic acid is chemically bonded to the surface.

The silica in which the organic acid is fixed on the surface is not particularly limited as the silica before the organic acid is fixed, and examples thereof include fumed silica and colloidal silica. Among these, colloidal silica is preferable. Further, in the case of silica having an organic acid fixed on the surface, the method for producing silica before fixing the organic acid is not particularly limited. However, from the viewpoint of enabling high-purity production and further improving the effect of the present invention, the sodium silicate method or the sol-gel method (sol-gel method) is the method for producing silica before fixing the organic acid. Preferably, the sol-gel method is more preferred. That is, as the silica before fixing the organic acid, at least of the colloidal silica produced by the sol-gel method or the sodium silicate method (for example, the colloidal silica produced by the sol-gel method and the colloidal silica produced by the sodium silicate method). On the other hand), it is preferable, and it is more preferable that it is colloidal silica produced by the sol-gel method.

In silica having an organic acid immobilized on the surface, the organic acid is not particularly limited, and examples thereof include sulfonic acid, carboxylic acid, and phosphoric acid. Among these, sulfonic acid or carboxylic acid is preferable, and sulfonic acid is more preferable. An acidic group derived from the organic acid (for example, a sulfo group, a carboxyl group, a phosphoric acid group, etc.) is covalently bonded (in some cases, via a linker structure) to the surface of silica having an organic acid immobilized on the surface. It will be fixed.

As the silica on which the organic acid is fixed on the surface, a synthetic product or a commercially available product may be used. Further, silica having an organic acid fixed on the surface may be used alone or in combination of two or more.

The method of introducing the organic acid onto the silica surface is not particularly limited, and examples thereof include a method of introducing the organic acid into the silica surface in the state of a mercapto group or an alkyl group, and then oxidizing the organic acid to a sulfonic acid or a carboxylic acid. Further, for example, a method of introducing the protecting group into the silica surface in a state where the protecting group is bonded to the acidic group derived from the organic acid and then removing the protecting group can be mentioned. Further, the compound used when introducing an organic acid onto the silica surface has at least one functional group that can be an organic acid group, and further, a functional group used for bonding with a hydroxyl group on the silica surface, hydrophobicity. -It is preferable to include a functional group introduced to control hydrophilicity, a functional group introduced to control steric bulkiness, and the like.

As a specific method for synthesizing silica with 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. 246-247 (2003). Specifically, sulfonic acid is immobilized on the surface by coupling a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane to silica and then oxidizing the thiol group with hydrogen peroxide. Silane can be obtained. Alternatively, if the carboxylic acid is to be immobilized on the surface of silica, for example, "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- It can be done by the method described in 229 (2000). Specifically, by coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to silica and then irradiating with light, silica having a carboxylic acid immobilized on the surface can be obtained.

The average primary particle size of the silica in which the organic acid is fixed on the surface in the polishing composition is not particularly limited, but is preferably 5 nm or more, more preferably 7 nm or more, and further preferably 10 nm or more. preferable. The average primary particle size of silica having an organic acid fixed on the surface in the polishing composition is preferably 50 nm or less, more preferably 45 nm or less, and further preferably 40 nm or less. Within these ranges, the polishing rate of a specific material by the polishing composition is further improved, and the selection ratio between different materials is further improved. In addition, the step reduction effect is further improved. Therefore, an example of a preferable average primary particle size of silica having an organic acid immobilized on the surface is 10 nm or more and 50 nm or less. The value of the average primary particle size of silica having an organic acid fixed on the surface can be calculated, for example, based on the specific surface area of silica having an organic acid fixed to the surface, which is measured by the BET method.

The average secondary particle size of the silica in which the organic acid is fixed on the surface in the polishing composition is not particularly limited, but is preferably 10 nm or more, more preferably 15 nm or more, and more preferably 20 nm or more. More preferred. The average secondary particle size of silica having an organic acid fixed on the surface in the polishing composition is not particularly limited, but is preferably 150 nm or less, more preferably 100 nm or less, and more preferably 80 nm or less. Is even more preferable. Within these ranges, the polishing rate of a specific material by the polishing composition is further improved, and the selection ratio between different materials is further improved. In addition, the step reduction effect is further improved. Therefore, an example of a preferable average secondary particle size of silica having an organic acid immobilized on the surface is 20 nm or more and 100 nm or less. The value of the average secondary particle diameter of silica having an organic acid fixed on the surface can be calculated based on, for example, a light scattering method measurement using a laser beam.

The degree of association of silica having an organic acid fixed on the surface in the polishing composition is not particularly limited, but is preferably 1 or more, more preferably 2 or more, and further preferably 2.5 or more. preferable. Further, the degree of association of silica having an organic acid fixed on the surface in the polishing composition is preferably 10 or less, more preferably 8 or less, still more preferably 5 or less. Within these ranges, the polishing rate of a specific material by the polishing composition is further improved, and the selection ratio between different materials is further improved. In addition, the step reduction effect is further improved. The degree of association of silica having an organic acid fixed on the surface can be calculated by dividing the value of the above average secondary particle size by the value of the above average primary particle size.

The zeta potential of silica in which the organic acid in the polishing composition is fixed on the surface is preferably a negative (minus) value, preferably -5 mV or less, and more preferably -10 mV or less. It is more preferably -15 mV or less. Within these ranges, silica agglutination is less likely to occur. Further, the zeta potential of silica in which the organic acid in the polishing composition is immobilized on the surface is preferably −70 mV or higher, more preferably −60 mV or higher, and further preferably −50 mV or higher. Within these ranges, it becomes more difficult for abrasive grains to adhere to the object to be polished. Specifically, the zeta potential of silica having an organic acid immobilized on the surface can be measured by the method described in Examples.

The shapes of the primary particles and the secondary particles of silica on which the organic acid is fixed on the surface are not particularly limited, and may be spherical or non-spherical, respectively. Among these, the shape of the secondary particles is preferably a cocoon shape, or a shape that is more deformed than the cocoon shape, such as a chain shape or a branched shape, and more preferably a cocoon shape.

The content (addition amount) of silica in which the organic acid is fixed on the surface in the polishing composition is not particularly limited, but is preferably 0.001% by mass or more, and preferably 0.01% by mass or more. It is more preferably 0.1% by mass or more, and even more preferably 0.1% by mass or more. Within these ranges, the polishing speed of the object to be polished by the polishing composition is further improved. Further, the content of silica in which the organic acid is fixed on the surface in the polishing composition is preferably 10% by mass or less, more preferably 8% by mass or less, and preferably 5% by mass or less. More preferred. Within these ranges, the polishing of a specific material by the polishing composition is further suppressed, and the selection ratio between different materials is further improved.

In the polishing composition according to the embodiment of the present invention, it is essential to use silica having an organic acid fixed on the surface as abrasive grains, but in some cases, silica having no organic acid fixed to the surface. Other abrasive grains such as may be used in combination. However, the content ratio of silica in which the organic acid is fixed on the surface in the entire abrasive grains is not particularly limited, but is preferably 50% by mass or more, more preferably 80% by mass or more, and 90% by mass. It is more preferably mass% or more, particularly preferably 95% by mass or more, and most preferably 100% by mass.

(Polyalkylene glycol)
The polishing composition according to one embodiment of the present invention contains polyalkylene glycol. Further, in the method for producing a polishing composition according to an embodiment of the present invention, polyalkylene glycol is used as a raw material.

The polyalkylene glycol preferably has two or more peaks in the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC). Here, "having two or more peaks" means that the chart (differential molecular weight distribution curve) of the molecular weight distribution of polyalkylene glycol by GPC has two or more maximum values. Typically, as described in the section of the method for producing a polishing composition described later, for example, for polishing using two or more kinds of polyalkylene glycols having different peak top molecular weights in the molecular weight distribution in terms of polyethylene glycol by GPC. By producing the composition, it is possible to obtain a composition that satisfies the condition of "having two or more peaks" as described above. Here, at least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 100 or more and 800 or less. Is preferable. The polyalkylene glycol contains polyethylene glycol, and at least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is preferably a peak derived from polyethylene glycol.

Here, in the polyethylene glycol-equivalent molecular weight distribution of polyalkylene glycol by GPC, it is preferable that at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polyethylene glycol. Further, the polyalkylene glycol further contains polypropylene glycol or polybutylene glycol, and at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polypropylene glycol or polybutylene glycol. preferable. It is particularly preferable that the polyalkylene glycol contained in the polishing composition according to the embodiment of the present invention is only polyethylene glycol, and all the peaks are derived from polyethylene glycol.

The number of peaks of the molecular weight distribution of polyalkylene glycol in terms of polyethylene glycol by GPC is not particularly limited as long as it is 2 or more, but is preferably 2 or more and 10 or less, more preferably 2 or 3, and 3 It is more preferable to have. Further, the number of peaks having a peak top molecular weight of 1,000 or more and 6,000 or less in the polyethylene glycol-equivalent molecular weight distribution by GPC of polyalkylene glycol is not particularly limited as long as it is 1 or more, but is 1 or more and 5 or less. It is preferably present, more preferably 1 or 2, and even more preferably 1. The number of peaks having a peak top molecular weight of 100 or more and 800 or less in the polyethylene glycol-equivalent molecular weight distribution by GPC of polyalkylene glycol is not particularly limited as long as it is 1 or more, but is preferably 1 or more and 5 or less. It is more preferably 1 or 2, and even more preferably 2. Within these ranges, the dispersed state of polyethylene glycol becomes better. In addition, more uniform and more precise adsorption to the object to be polished becomes possible, and better control of the step shape, which cannot be achieved by a single peak, becomes possible.

At least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less in the polyethylene glycol-equivalent molecular weight distribution of polyalkylene glycol by GPC is not particularly limited, but is 1,100 or more and 5,000 or less. It is preferable to have a top molecular weight, and it is more preferable to have a peak top molecular weight of 1,200 or more and 4,000 or less. Within these ranges, the selectivity is further improved between different materials. In addition, the step reduction effect is further improved. When the polyalkylene glycol has a plurality of peaks having a peak top molecular weight of 1,000 or more and 6,000 or less, it is preferable that all the peaks have a peak top molecular weight within the above range. At this time, the selection ratio is further improved between different materials. In addition, the step reduction effect is further improved.

At least one of the peaks having a peak top molecular weight of 100 or more and 800 or less in the polyethylene glycol-equivalent molecular weight distribution of polyalkylene glycol by GPC is not particularly limited, but more preferably has a peak top molecular weight of 150 or more and 700 or less. It is even more preferable to have a peak top molecular weight of 200 or more and 600 or less. Within this range, the selectivity is further improved between different materials. In addition, the step reduction effect is further improved. When the polyalkylene glycol has a plurality of peaks having a peak top molecular weight of 100 or more and 800 or less, it is preferable that all the peaks are within the above range. At this time, the selection ratio is further improved between different materials. In addition, the step reduction effect is further improved.

When two or more kinds of polyalkylene glycols are used as the raw material, the polyalkylene glycol as the raw material is not particularly limited, but for example, poly having a peak top molecular weight in the same range as the preferable range of each of the above peaks. Examples thereof include alkylene glycol and the like.

The molecular weight distribution of polyalkylene glycol in terms of polyethylene glycol by GPC and the peak top molecular weight can be specifically measured by the method described in Examples. The number average molecular weight and the weight average molecular weight can also be measured by the same method.

The polyalkylene glycol contained in the polishing composition may be composed of a commercially available product or a synthetic product. Further, the polyalkylene glycol contained in the polishing composition may be composed of a single type of polyalkylene glycol or may be composed of two or more types of polyalkylene glycol. Among these, the polyalkylene glycol is preferably composed of a single type of polyalkylene glycol.

The type of polyalkylene glycol is not particularly limited, but is a polyalkylene glycol such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and at least two or more copolymers selected from the group consisting of ethylene glycol, propylene glycol and glycol. And so on. Among these, polyethylene glycol and polypropylene glycol are preferable, and polyethylene glycol is more preferable.

When two or more kinds of polyalkylene glycols are used as the raw material, the polyalkylene glycol as the raw material is not particularly limited, and examples thereof include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol. .. The commercial product is not particularly limited, but for example, polyethylene glycol 200, 600, 1,000, 1,540, 2,000, 4,000, 6,000, 8,000, 20,000 (or more, Fuji Film). Wako Pure Chemical Industries, Ltd.), Polyethylene glycol 10,000 (manufactured by Alfa Aesar), polypropylene glycol, diol type, 400 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and the like. Further, block polymers represented by the Pronon (registered trademark) series such as Pronon (registered trademark) 102 and Pronon (registered trademark) 201 (all manufactured by NOF CORPORATION) and the like can be mentioned. Among these, polyethylene glycol and polypropylene glycol are preferable, and polyethylene glycol is more preferable.

The content (addition amount) of the polyalkylene glycol in the polishing composition is not particularly limited, but is preferably 0.001 g / L or more, more preferably 0.01 g / L or more, and 0. It is more preferably 1 g / L or more. The content of the polyalkylene glycol in the polishing composition is preferably 100 g / L or less, more preferably 10 g / L or less, and further preferably 5 g / L or less. Within these ranges, the selectivity is further improved between different materials. In addition, the step reduction effect is further improved.

As raw materials, polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less and polyalkylene having a peak top molecular weight of 100 or more and 800 or less in the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC). When using glycol, the ratio of the amount of polyethylene glycol added having a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of these additions is not particularly limited, but is 10% by mass or more. It is more preferably 20% by mass or more, further preferably 40% by mass or more, further preferably 70% by mass or more, and particularly preferably 75% by mass or more. The ratio of the amount of polyethylene glycol added having a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of these additions is preferably 90% by mass or less, preferably 85% by mass or less. Is more preferable, and 80% by mass or less is further preferable.

(Abrasion accelerator)
The polishing composition according to one embodiment of the present invention preferably contains a polishing accelerator. Further, in the method for producing a polishing composition according to an embodiment of the present invention, it is preferable to use a polishing accelerator as a raw material. The polishing accelerator acts to improve the polishing rate of a particular material by the polishing composition. As a result, the selectivity is further improved between different materials.

The polishing accelerator is not particularly limited, but is a compound capable of improving the polishing rate of a material having a positive zeta potential at the pH of the polishing composition (polishing accelerator for a material having a positive zeta potential). Is preferable. Further, the compound may be a compound capable of improving the polishing rate of a material having a silicon-nitrogen bond such as silicon nitride (a polishing accelerator for a material having a silicon-nitrogen bond, preferably a polishing accelerator for silicon nitride). More preferred. Such compounds are more polished when using silica with an organic acid fixed to the surface, which has a negative zeta potential, even if the positive absolute value of the zeta potential of the material to be polished is small. Speed and high selectivity can be achieved.

The polishing accelerator for a material having a silicon-nitrogen bond such as silicon nitride is not particularly limited, and is, for example, N-methyl-D-glucamine, D-glucamine, N-ethyl-D-glucamine, N-propyl-D. -Glucamine, N-octyl-D-glucamine, N-acetyl-D-glucosamine, tris (hydroxymethyl) aminomethane, bis (2-hydroxyethyl) aminotris (hydroxymethyl) methane, N- (2-acetamido) imino Diacetic acid, N, N-di (2-hydroxyethyl) glycine, N- [tris (hydroxymethyl) methyl] glycine, hydroxyethyliminodiacetic acid, iminodiacetic acid, hydroxyethylidene diphosphonic acid (HEDP), nitrilotrismethylene Phosphonic acid, phosphonobutane tricarboxylic acid, salts thereof and the like can be mentioned. Further, alkanolamines, amino acids, salts thereof and the like can be mentioned. Among these, N-methyl-D-glucamine is preferable.

As the polishing accelerator, a synthetic product or a commercially available product may be used. Further, the polishing accelerator may be used alone or in combination of two or more.

The content (addition amount) of the polishing accelerator in the polishing composition is not particularly limited, but is preferably 0.01 g / L or more, more preferably 0.1 g / L or more, and 1 g / L. It is more preferably L or more. Within these ranges, the effect of the polishing accelerator on improving the polishing speed of a specific material is further enhanced. The content of the polishing accelerator in the polishing composition is preferably 100 g / L or less, more preferably 50 g / L or less, and further preferably 10 g / L or less. Within such a range, the possibility of reprecipitation of the polishing accelerator can be further reduced. In addition, the possibility of deterioration of the polishing composition due to the reaction between the polishing accelerator and other additives can be further reduced.

(Step improver)
The polishing composition according to one embodiment of the present invention preferably contains a step improving agent. Further, in the method for producing a polishing composition according to an embodiment of the present invention, it is preferable to use a step improving agent as a raw material. The step improver acts to reduce unintentional steps between different materials related to a specific combination of materials and unintentional steps between coarse and dense portions of the pattern.

The step improving agent is not particularly limited, but further improves the step reducing effect of the object to be polished including a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-oxygen bond such as silicon oxide. (Preferably, a step improving agent between a material having a silicon-nitrogen bond and a material having a silicon-oxygen bond, more preferably a step improving agent between silicon nitride and silicon oxide). .. Further, a compound (preferably silicon) capable of further improving the step reduction effect of the object to be polished, including a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-silicon bond such as polycrystalline silicon. -A step improving agent between a material having a nitrogen bond and a material having a silicon-silicon bond, more preferably a step improving agent between silicon nitride and polycrystalline silicon).

A step improver between a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-oxygen bond such as silicon oxide, a material having a silicon-nitrogen bond such as silicon nitride, and silicon such as polycrystalline silicon. -The step improving agent with a material having a silicon bond is not particularly limited, and preferred examples include a compound having an aromatic ring and a sulfo group that directly bonds to the aromatic ring, and a salt thereof. The aromatic ring may be an aromatic hydrocarbon ring, an aromatic heterocycle, a monocyclic ring, or a ring formed by condensing two or more rings. More specifically, for example, the compound represented by the following general formula (1) and a salt thereof, the compound represented by the following general formula (2) and a salt thereof, and the following general formula (3) are represented. It is preferably at least one selected from the group consisting of a (co) polymer containing a structural unit thereof and a salt thereof. That is, a compound represented by the following general formula (1), a compound represented by the following general formula (2), a (co) polymer containing a structural unit represented by the following general formula (3), and salts thereof. It is preferably at least one selected from the group consisting of. The (co) polymer is a general term including a copolymer and a homopolymer.

In the above general formula (1), R ¹ to R ⁶ are independently each of a hydrogen atom, a hydroxy group, a sulfo group, an anionic group containing no sulfo group, a cationic group, and an alkoxycarbonyl having 2 to 6 carbon atoms. It is a group or a hydrocarbon group having 1 to 10 carbon atoms, and at least one of R ¹ to R ⁶ is a sulfo group.

In the above general formula (2), R ⁷ to R ¹⁴ are independently each of a hydrogen atom, a hydroxy group, a sulfo group, an anionic group containing no sulfo group, a cationic group, and an alkoxycarbonyl having 2 to 6 carbon atoms. It is a group or a hydrocarbon group having 1 to 10 carbon atoms, and at least one of R ⁷ to R ¹⁴ is a sulfo group.

In the above general formula (3), each of R ¹⁵ to R ¹⁹ independently has a hydrogen atom, a hydroxy group, a sulfo group, an anionic group containing no sulfo group, a cationic group, and an alkoxycarbonyl having 2 to 6 carbon atoms. A group or a hydrocarbon group having 1 to 10 carbon atoms, in which case at least one of R ¹⁵ to R ¹⁹ is a sulfo group, and R ²⁰ to R ²² are independent hydrogen atoms and hydroxy groups, respectively. , Anionic group without sulfo group, cationic group, alkoxycarbonyl group with 2 to 6 carbon atoms, or hydroxy group, anionic group without sulfo group, cationic group, or alkoxycarbonyl with 2 to 6 carbon atoms It is a group-substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms.

In the general formulas (1) to (3), the anionic group means a functional group in which counter ions are dissociated to become an anion. Further, in the general formulas (1) to (3), the cationic group is a cation by dissociating a counter ion or binding to a cation species generated by ionization of another ionic compound. Means a functional group. The cationic group is not particularly limited, and examples thereof include an amino group and the like.

In the general formulas (1) to (3), the amino group represents an -NH ₂ group, an -NHR group, and an -NRR'group (R and R'represent a substituent). Further, in the general formulas (1) to (3), the alkoxycarbonyl group having 2 to 6 carbon atoms is not particularly limited, but is a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyroxycarbonyl group, or an isopropi. Preferred examples include a loxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group and the like. The hydrocarbon group having 1 to 10 carbon atoms in the general formulas (1) to (3) is not particularly limited, but is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or n-. Preferred examples include a butyl group, a sec-butyl group, a tert-butyl group and the like.

Moreover, the copolymer containing the structural unit represented by the general formula (3) or a salt thereof may further contain a structural unit derived from another monomer. The structural unit derived from other monomers of the copolymer containing the structural unit represented by the general formula (3) or a salt thereof is not particularly limited, but is an ethylenically unsaturated monomer, a diamine, and the like. Alternatively, a structural unit derived from a diepoxide and the like can be mentioned as a preferable example. The weight average molecular weight of the (co) polymer containing the structural unit represented by the general formula (3) or a salt thereof is not particularly limited, but is preferably 1,000 or more. The weight average molecular weight of the (co) polymer containing the structural unit represented by the general formula (3) or a salt thereof is preferably 1,000,000 or less. The weight average molecular weight of the (co) polymer containing the structural unit represented by the general formula (3) or a salt thereof can be obtained as a polystyrene-equivalent value measured by GPC.

Among these, it has a step reduction effect of a polishing object including a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-oxygen bond such as silicon oxide, and a silicon-nitrogen bond such as silicon nitride. From the viewpoint of the step reducing effect of the object to be polished including the material and the material having a silicon-silicon bond such as polycrystalline silicon, the step reducing agent is a compound represented by the general formula (1) or a salt thereof. Is preferable. Further, in the compound represented by the general formula (1) or a salt thereof, in the general formula (1), R ¹ is a sulfo group, and R ² to R ⁶ are independently hydrogen atoms. It is preferably a compound having a hydroxy group, an anionic group containing no sulfo group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms, or a salt thereof. In the compound represented by the general formula (1) or a salt thereof, R ¹ is a sulfo group and R ² to R ⁶ are independently hydrogen atoms in the general formula (1). -It is more preferably a compound having ₂ NHs, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group, or a salt thereof. Further, in the compound represented by the general formula (1) or a salt thereof, in the general formula (1), R ¹ is a sulfo group, and R ² to R ⁶ are independently hydrogen atoms. Alternatively, it is more preferably a compound which is a methyl group or a salt thereof.

Further, a material having a silicon-nitrogen bond such as silicon nitride and a material having a silicon-nitrogen bond such as silicon nitride and a material having a step reduction effect of a polishing object including a material having a silicon-oxygen bond such as silicon oxide. From the viewpoint of the step reducing effect of the object to be polished including a material having a silicon-silicon bond such as polycrystalline silicon, specific examples of the preferable step reducing agent are not particularly limited, but are m-xylene sulfonic acid or the same. A salt, p-toluidine-2-sulfonic acid or a salt thereof, 2-naphthol-6-sulfonic acid or a salt thereof, 1-naphthalene sulfonic acid or a salt thereof, a parastyrene sulfonic acid-styrene copolymer or a salt thereof. Examples include salt. Therefore, specific examples of the preferable step reducing agent are not particularly limited, but are m-xylene sulfonic acid, p-toluidine-2-sulfonic acid, 2-naphthol-6-sulfonic acid, 1-naphthalene sulfonic acid, and parastyrene sulfonic acid. Examples thereof include acid-styrene copolymers and salts thereof. Among these, m-xylene sulfonic acid or a salt thereof, p-toluidine-2-sulfonic acid, or a salt thereof, which is the compound represented by the general formula (1) or a salt thereof, is more preferable, and m- Xylene sulfonic acid, or a salt thereof, is more preferable, and m-xylene sulfonic acid is particularly preferable. Therefore, more preferable specific examples include m-xylene sulfonic acid, p-toluidine-2-sulfonic acid, and salts thereof, and further preferred specific examples include m-xylene sulfonic acid and salts thereof. Specific preferred examples thereof include m-xylene sulfonic acid.

When the step improving agent is a salt, a sulfo group or a part or all of other functional groups capable of forming a salt may be a salt.

As the step improving agent, a synthetic product or a commercially available product may be used. Further, the step improving agent may be used alone or in combination of two or more.

The content (addition amount) of the step improving agent in the polishing composition is not particularly limited, but is preferably 0.01 g / L or more, more preferably 0.1 g / L or more, and 1 g / L. It is more preferably L or more. Within these ranges, the effect of reducing the step unintentionally generated between different materials related to a specific combination of materials and the step unintentionally generated between the coarse and dense portions of the pattern is further enhanced. Further, the content of the step improving agent in the polishing composition is preferably 100 g / L or less, more preferably 50 g / L or less, and further preferably 10 g / L or less. Within such a range, the possibility of reprecipitation of the step improving agent can be further reduced. In addition, the possibility of deterioration of the polishing composition due to the reaction between the step improving agent and other additives can be further reduced.

The step improver may be in the state of the step improver itself or in the state of its hydrate at the time of mixing when preparing the polishing composition. When the step improving agent is mixed in the state of its hydrate, the content of the step improving agent in the polishing composition represents the content calculated from the mass excluding the hydrated water.

(PH regulator)
The polishing composition according to one embodiment of the present invention preferably contains a pH adjuster. Further, in the method for producing a polishing composition according to an embodiment of the present invention, it is preferable to use a pH adjuster as a raw material. The pH adjuster acts to adjust the pH of the polishing composition to a desired value by adding an appropriate amount to the polishing composition.

The pH adjusting agent is not particularly limited, and a known pH adjusting agent used in the field of polishing compositions can be used. Among these, it is preferable to use known acids, bases, salts thereof and the like.

The acid as the pH adjuster is not particularly limited and may be an inorganic acid or an organic acid. The inorganic acid is not particularly limited, and is, for example, carbonic acid, hydrochloric acid, nitric acid, phosphoric acid, hypophosphoric acid, phosphite, phosphonic acid, sulfuric acid, boric acid, hydrofluoric acid, orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid. Acids, metaphosphoric acid, hexametaphosphoric acid and the like can be mentioned. Among these, nitric acid is preferable.

Examples of the organic acid include a carboxylic acid, an organic phosphorus-based acid having a phosphonic acid group or a phosphonic acid group, and a sulfonic acid. Among these, carboxylic acid is preferable.

The organic acid may be an organic acid having only one organic acid group in the molecule or an organic acid having two or more organic acid groups in the molecule. The organic acid having only one organic acid group in the molecule is not particularly limited, but is, for example, a group consisting of a carboxy group (carboxylic acid group), a phosphonic acid group or a phosphoric acid group, and a sulfo group (sulfonic acid group). It is preferable that the organic acid has at least one organic acid group selected from the above in the molecule. Specifically, the present invention is not particularly limited, but for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexaneic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentane. Monocarboxylic acids such as acids, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, hydroxyisobutyric acid, salicylic acid and lactic acid, methanesulfonic acid and ethanesulfone. Examples thereof include acids, monosulfonic acids such as isethionic acid, and monovalent organic phosphorus-based acids. The organic acid having two or more organic acid groups in the molecule is not particularly limited, and is, for example, composed of a carboxy group (carboxylic acid group), a phosphonic acid group or a phosphoric acid group, and a sulfo group (sulfonic acid group). It is preferable that the organic acid has at least one organic acid group selected from the group and has two or more organic acid groups in the molecule. Specific examples thereof are not particularly limited, but are, for example, succinic acid, adipic acid, glutaric acid, pimelic acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2-. Polyvalent carboxylic acids such as pentendioic acid, methylene succinic acid, allylmalonic acid, isopropyridene succinic acid, 2,4-hexadiennic acid, acetylenedicarboxylic acid, citric acid, malic acid, tartrate acid, aconitic acid, itaconic acid, meritonic acid, etc. , Polyvalent organic phosphorus-based acids such as polyvalent sulfonic acid, phytic acid, hydroxyethidylene diphosphonic acid and the like can be mentioned.

Specific examples of the base are not particularly limited, but examples thereof include hydroxides of alkali metals such as potassium hydroxide, quaternary ammonium salts such as ammonia, tetramethylammonium and tetraethylammonium, amines such as ethylenediamine and piperazine, and the like. Can be mentioned.

Among these, an acid is preferable, an acid having two or more acidic groups in the molecule is more preferable, and an organic acid having two or more organic acid groups in the molecule is further preferable. Further, a polyvalent carboxylic acid is more preferable, an aliphatic polyvalent carboxylic acid is particularly preferable, and an unsaturated aliphatic polyvalent carboxylic acid is even more preferable. The unsaturated aliphatic divalent carboxylic acid is extremely preferable, and maleic acid is most preferable.

The content (addition amount) of the pH adjuster in the polishing composition is not particularly limited as long as the pH of the polishing composition is 3 or more and 6 or less, but is a preferable pH value of the polishing composition described later. It is preferable to add an amount such that

(Dispersion medium)
The polishing composition according to one embodiment of the present invention preferably contains a dispersion medium. Further, in the method for producing a polishing composition according to an embodiment of the present invention, it is preferable to use a dispersion medium as a raw material. The dispersion medium acts to disperse or dissolve each component.

The dispersion medium is not particularly limited, and examples thereof include water and an organic solvent. The organic solvent is not particularly limited, and a known organic solvent can be used. Among these, the dispersion medium preferably contains water, and more preferably only water. Further, from the viewpoint of preventing the influence of impurities on other components of the polishing composition, it is preferable to use water having the highest possible purity. Specifically, pure water, ultrapure water, or distilled water from which foreign substances have been removed through a filter after removing impurity ions with an ion exchange resin is preferable. Further, as a dispersion medium, for the purpose of controlling the dispersibility of other components of the polishing composition, in addition to water, acetone, acetonitrile, methanol, ethanol, isopropanol, glycerin, and ethylene, which are organic solvents that are miscible with water, are used. It may further contain an organic solvent such as glycol or propylene glycol. When an organic solvent miscible with water is used in addition to water, water and the organic solvent may be mixed, and each component may be added to the obtained mixed solvent to disperse or dissolve. Further, these organic solvents may be used without being mixed with water to disperse or dissolve each component and then to be mixed with water. The organic solvent miscible with these waters can be used alone or in combination of two or more.

(Other ingredients)
The polishing composition according to one embodiment of the present invention may further contain other known components used in the field of polishing compositions, if necessary. Further, in the method for producing a polishing composition according to an embodiment of the present invention, other known components used in the field of polishing compositions may be further used as a raw material, if necessary. The other components are not particularly limited, but are, for example, complexing agents, metal anticorrosive agents, preservatives, fungicides, oxidizing agents, reducing agents, electrical conductivity modifiers, and highly water-soluble components other than those described above. Examples include molecules. Among these, it is preferable to contain an antiseptic or an antifungal agent.

The preservative or antifungal agent is not particularly limited, and a known preservative or a known antifungal agent used in the field of polishing compositions can be used. Specifically, for example, isothiazolin-based preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, paraoxybenzoic acid esters, phenoxyethanol and the like. Can be mentioned.

(PH of polishing composition)
In one embodiment of the present invention, the pH of the polishing composition is 3 or more and 6 or less. When the pH value is larger than 6, the absolute value of the positive zeta potential of the material having a positive zeta potential becomes small. Therefore, when silica with an organic acid having a negative zeta potential fixed on the surface is used. , It becomes difficult to polish at a high polishing speed. Also, as a result, the selectivity is reduced among dissimilar materials including such materials. The pH of the polishing composition is preferably 5.5 or less, more preferably 5 or less. Within these ranges, the polishing composition polishes the material with a positive zeta potential at a sufficient polishing rate, while having a higher selectivity and a higher step reduction between different materials in a wide range of combinations including this. The effect can be obtained. On the other hand, when the pH value is less than 3, the selectivity between different materials decreases. For example, when a material having a silicon-oxygen bond such as silicon oxide exists in the vicinity of a material having a silicon-nitrogen bond such as silicon nitride on an object to be polished, silicon-nitrogen for a material having a silicon-oxygen bond. It becomes impossible to secure a sufficient selection ratio of the material having a bond. The pH of the polishing composition is preferably 3.5 or higher, more preferably 4.5 or higher. Within these ranges, a higher selectivity and a higher step reduction effect can be obtained between different materials having a wide range of combinations including materials having a positive zeta potential. The pH of the polishing composition can be measured by the method described in Examples. Further, the pH of the polishing composition can be adjusted by, for example, the amount of a pH adjuster added.

(Type of polishing composition)
The polishing composition according to one embodiment of the present invention or the polishing composition produced by the method for producing a polishing composition according to one embodiment of the present invention may be a one-component type or a two-component type. It may be a multi-component type such as a mold. In the case of a multi-component type, the polishing composition according to one embodiment of the present invention or the polishing composition produced by the method for producing a polishing composition according to one embodiment of the present invention is one of the liquids. However, it may be two or more liquids or all liquids. Further, in the polishing composition produced by the polishing composition according to one embodiment of the present invention or the method for producing a polishing composition according to one embodiment of the present invention, the undiluted solution of the polishing composition is water or the like. It may be adjusted by, for example, diluting 10 times or more with the diluted solution of.

(Object to be polished)
A polishing composition according to one aspect of the present invention, a polishing composition produced by a production method according to another aspect of the present invention described later, a polishing method according to another aspect of the present invention described later, and a later description. The polishing object to which the method for producing a substrate according to still another aspect of the present invention is applied is not particularly limited, and can be applied to a known polishing object used in the CMP field. Examples of the object to be polished include an object to be polished containing a metal, a material having a silicon-nitrogen bond, and another material containing silicon.

The polishing target is preferably a polishing target containing two or more kinds of materials, and more preferably a polishing target containing (a) a material having a silicon-nitrogen bond and (b) another material containing silicon. ..

(A) Material having a silicon-nitrogen bond The material having a silicon-nitrogen bond is not particularly limited, and examples thereof include silicon nitride (SiN) and silicon nitride (SiCN).

(B) Other Silicon-Containing Materials The other silicon-containing materials are not particularly limited as long as they are silicon-containing materials other than the above-mentioned silicon-nitrogen bond-containing materials, and examples thereof include the following.

(B-1) Material having a silicon-oxygen bond The material having a silicon-oxygen bond is not particularly limited, and is, for example, silicon oxide, BD (black diamond: SiOCH), FSG (fluorosilicate glass), HSQ (hydrogen). (Silsesquioxane), CYCLOTENE, SiLK, MSQ (Methyl silsesquioxane) and the like can be mentioned. Among these, silicon oxide is preferable. The silicon oxide is not particularly limited, but is particularly preferably silicon oxide derived from tetraethyl orthosilicate (TEOS) (also simply referred to as "TEOS-SiO" in the present specification).

(B-2) Material having a silicon-silicon bond The object to be polished having a silicon-silicon bond is not particularly limited, and is, for example, polycrystalline silicon (polysilicon, Poly-Si), amorphous silicon, single crystal silicon, and the like. Examples thereof include n-type doped monocrystalline silicon, p-type doped monocrystalline silicon, and Si-based alloys such as SiGe. Among these, polycrystalline silicon is preferable.

Therefore, the polishing composition according to one aspect of the present invention, the polishing composition produced by the production method according to another aspect of the present invention described later, the polishing method according to another aspect of the present invention described later, The polishing object to which the method for producing a substrate according to still another aspect of the present invention, which will be described later, is applied, includes (a) a material having a silicon-nitrogen bond and (b) another material containing silicon. It is preferably used for polishing objects.

Further, these polishing compositions include (a) a material having a silicon-nitrogen bond, (b-1) a material having a silicon-oxygen bond, and (b-2) a material having a silicon-silicon bond. It is more preferable that it is used for polishing an object to be polished. Further, it is more preferable that these polishing compositions are used for polishing an object to be polished containing silicon nitride and silicon oxide (for example, TEOS-SiO) or polysilicon. Therefore, these polishing compositions include (a) a material having a silicon-nitrogen bond, (b-1) a material having a silicon-oxygen bond, and (b-2) a material having a silicon-silicon bond. It is more preferable that it is used for polishing an object to be polished including at least one of them. Further, it is more preferable that these polishing compositions are used for polishing an object to be polished containing silicon nitride and at least one of silicon oxide (for example, TEOS-SiO) and polysilicon.

Further, these polishing compositions include (a) a material having a silicon-nitrogen bond, (b-1) a material having a silicon-oxygen bond, and (b-2) a material having a silicon-silicon bond. It is also more preferable that it is used for polishing an object to be polished. Further, it is further preferable that these polishing compositions are used for polishing an object to be polished containing silicon nitride, silicon oxide (for example, TEOS-SiO, etc.), and polysilicon.

By applying these polishing compositions to the above-mentioned polishing target, a higher polishing rate for a specific material is realized, and a higher selection ratio and a higher step reduction effect are realized between different materials. can do.

The polishing object including (a) a material having a silicon-nitrogen bond and (b) another material containing silicon may contain other materials, if necessary. The other material is not particularly limited, and examples thereof include metal and the like. The metal is not particularly limited, and examples thereof include copper, aluminum, hafnium, cobalt, nickel, titanium, and tungsten.

The object to be polished is preferably a substrate as a product form.

<Manufacturing method of polishing composition>
Another aspect of the present invention comprises a mixing step of mixing silica having an organic acid immobilized on the surface and polyalkylene glycol, and polyethylene glycol obtained by gel permeation chromatography (GPC) for the polyalkylene glycol. The converted molecular weight distribution has two or more peaks, and at least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is The peak top molecular weight is 100 or more and 800 or less, and the polyalkylene glycol contains polyethylene glycol, and at least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is polyethylene. The present invention relates to a method for producing a composition for polishing, which is a peak derived from glycol and has a pH of 3 or more and 6 or less. According to this aspect, it is possible to provide a means capable of realizing a remarkably high selection ratio and a remarkably high step reduction effect between different materials while realizing a high polishing rate for a specific material.

In addition, another aspect of the present invention has a peak top molecular weight of 1,000 or more and 6,000 or less in a polyethylene glycol-equivalent molecular weight distribution of silica having an organic acid immobilized on the surface and gel permeation chromatography (GPC). It has a mixing step of mixing polyethylene glycol, which is a polyethylene glycol, and a polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less in a polyethylene glycol-equivalent molecular weight distribution by gel permeation chromatography (GPC), and has a pH of 3 or more. The present invention relates to a method for producing a polishing composition, which is 6 or less. The manufacturing method according to the above aspect may be a preferred embodiment of the manufacturing method according to the above aspect. According to this aspect, it is possible to provide a means capable of realizing a remarkably high selection ratio and a remarkably high step reduction effect between different materials while realizing a high polishing rate for a specific material.

In these aspects, the details of the raw material, physical properties, and characteristics of the polished composition to be manufactured, the object to be polished to which the manufactured polishing composition is applied, and the like are also the same as the description of the above-mentioned polishing composition. Is.

Further, it can be said that the production method according to these aspects is a preferable example of the production method for producing the above-mentioned polishing composition. Therefore, the polishing composition produced by the production method according to these aspects preferably contains silica having an organic acid immobilized on the surface and polyalkylene glycol, and gel permeation on the polyalkylene glycol. The polyethylene glycol-equivalent molecular weight distribution by chromatography (GPC) has two or more peaks, and at least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less. At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 100 or more and 800 or less, the polyalkylene glycol containing polyethylene glycol, and a peak having a peak top molecular weight of 1,000 or more and 6,000 or less. At least one of the above is a peak derived from polyethylene glycol, which is a polishing composition having a pH of 3 or more and 6 or less. In this case, the details of the polishing composition to be produced, the components contained therein, the polishing object to which the polishing composition is applied, and the like are also the same as the description of the above-mentioned polishing composition.

The mixing step involves mixing silica having an organic acid immobilized on the surface and two or more kinds of polyalkylene glycols having different peak top molecular weights in the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC). Is preferable. Therefore, silica having an organic acid immobilized on the surface and at least one peak of the molecular weight distribution are peaks having a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak top molecular weight. When mixing with polyalkylene glycol having a peak of 100 or more and 800 or less, in the mixing step, at least one peak of the molecular weight distribution is a polyalkylene having a peak top molecular weight of 1,000 or more and 6,000 or less. It is preferable that the glycol and at least one peak of the molecular weight distribution include mixing a polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less. Further, in this case, in the mixing step, at least one peak of the molecular weight distribution is polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak top molecular weight. It is preferable to include mixing with polyalkylene glycol having a peak of 100 or more and 800 or less.

In the mixing step, the above-mentioned polishing accelerator, the above-mentioned step improver, the above-mentioned pH adjuster, the above-mentioned dispersion medium, or the above-mentioned other components may be further mixed, if necessary.

The temperature at which each component is mixed is not particularly limited, but is preferably 10 to 40 ° C., and may be heated in order to increase the dissolution rate.

Further, the polishing composition according to the embodiment of the present invention is prepared by preparing a stock solution of the polishing composition by the above method, and then diluting the stock solution with a diluted solution such as water (for example, 10). It may be adjusted by diluting it by a factor of 2 or more.

<Polishing method>
In another aspect of the present invention, the polishing composition is produced by using the above-mentioned polishing composition or by the above-mentioned production method, and the polishing object is polished by using the polishing composition. Regarding the polishing method.

It can be said that this aspect is an example of a polishing method using the above-mentioned polishing composition or the polishing composition produced by the above-mentioned production method. From this, the details of the polishing composition, the components contained therein, the polishing target to which the polishing composition is applied, and the like are also the same as the above description of the polishing composition. Further, details of the raw material, physical properties, and characteristics of the produced polishing composition, the polishing target to which the produced polishing composition is applied, and the like are also described in the above-mentioned polishing composition and the above-mentioned polishing composition. It is the same as the explanation of the manufacturing method of a thing. Therefore, as an example of a preferred embodiment, as described above, a polishing method in which the object to be polished includes a material having a silicon-nitrogen bond and another material containing silicon; the object to be polished is a silicon-nitrogen bond. A polishing method comprising a material having a silicon-oxygen bond or a material having a silicon-silicon bond; a material having a silicon-nitrogen bond and a material having a silicon-oxygen bond as the object to be polished. And a polishing method comprising at least one of a material having a silicon-silicon bond; the object to be polished is a material having a silicon-nitrogen bond, a material having a silicon-oxygen bond, and a material having a silicon-silicon bond. Polishing method; the polishing target includes silicon nitride and silicon oxide (for example, TEOS-SiO) or polycrystalline silicon; the polishing target includes silicon nitride and silicon oxide. (For example, TEOS-SiO etc.) and a polishing method including polycrystalline silicon; and the like. From this, the polishing method according to the embodiment of the present invention can be preferably used for polishing a pattern wafer such as a polysilicon pattern wafer.

In one embodiment of the present invention, when polishing an object to be polished using the polishing composition, it can be carried out using the equipment and conditions used for ordinary polishing. As a general polishing device, there are a single-sided polishing device and a double-sided polishing device. In a single-sided polishing device, a holder called a carrier is used to hold the substrate, and while supplying the polishing composition from above, the surface plate with the polishing pad attached is pressed against the facing surface of the substrate to rotate the surface plate. Polishes one side of the material to be polished (object to be polished). At this time, the polishing pad and the polishing composition are polished by the physical action due to friction between the polishing object and the polishing object, and the chemical action that the polishing composition brings to the polishing object. As the polishing pad, a porous body such as a non-woven fabric, polyurethane, or suede can be used without particular limitation. It is preferable that the polishing pad is processed so that the polishing liquid collects.

Polishing conditions include a polishing load, a surface plate rotation speed, a carrier rotation speed, a flow rate of a polishing composition, a polishing time, and the like. These polishing conditions are not particularly limited, but for example, the polishing load is 0.1 psi or more and 10 psi or less (0.7 to 68.9 kPa, 1 psi = 6894.76 Pa) per unit area of the substrate. ), More preferably 0.5 psi or more and 8 psi or less (3.4 to 55.1 kPa), and further preferably 1 psi or more and 6 psi or less (6.9 to 41.4 kPa). Generally, the higher the load, the higher the frictional force due to the abrasive grains, and the higher the mechanical processing force, so that the polishing speed increases. Within this range, a higher polishing speed can be exhibited, and damage to the substrate due to a load and defects such as scratches on the surface can be further suppressed. The surface plate rotation speed and the carrier rotation speed are preferably 10 to 500 rpm (0.2 to 8.3 s ^-1 , and 60 rpm = 1 s ^-1 ; the same applies hereinafter). The supply amount of the polishing composition may be any supply amount (flow rate) that covers the entire polishing object, and may be adjusted according to conditions such as the size of the polishing object. The method of supplying the polishing composition to the polishing pad is also not particularly limited, and for example, a method of continuously supplying the polishing composition with a pump or the like is adopted. Further, the processing time is not particularly limited as long as the desired processing result can be obtained, but it is preferably a shorter time due to the high polishing rate.

<Manufacturing method of substrate>
Yet another aspect of the present invention relates to a method for manufacturing a substrate, which comprises a step of polishing an object to be polished by the above-mentioned polishing method.

It can be said that this aspect is a preferable example of a method for producing a substrate, which includes the above-mentioned polishing composition and a polishing method using the above-mentioned polishing composition produced by the above-mentioned production method. From this, the details of the polishing composition, the components contained therein, the polishing target to which the polishing composition is applied, and the like are also the same as the above description of the polishing composition. Further, details of the raw material, physical properties, and characteristics of the produced polishing composition, the polishing target to which the produced polishing composition is applied, and the like are also described in the above-mentioned polishing composition and the above-mentioned polishing composition. It is the same as the explanation of the manufacturing method of a thing. The details of the polishing method are also the same as those described above. Therefore, as an example of a preferable embodiment, a method for manufacturing a substrate (polished substrate) in which the object to be polished is a substrate, or a method for manufacturing a semiconductor substrate (polished semiconductor substrate) in which the object to be polished is a semiconductor substrate. The method and the like can be mentioned. Therefore, the method for manufacturing a substrate according to an embodiment of the present invention can be preferably used for manufacturing a patterned wafer such as a polysilicon pattern wafer.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. In the following examples, unless otherwise specified, the operation was performed under the conditions of room temperature (25 ° C.) / relative humidity of 40 to 50% RH.

<Preparation of polishing composition>
Abrasive grains, polyalkylene glycol or ethylene glycol (EG), a pH adjuster, and other additives to be added as necessary are added to water as a solvent, and the mixture is stirred and mixed to obtain each polishing composition. (Mixing temperature about 25 ° C., mixing time: about 10 minutes). Here, the types and concentrations (contents, addition amounts) of each component used in the preparation of each polishing composition are shown in Table 1 below and Table 2 below. The concentration (content, addition amount) of the pH adjuster was set so that the obtained polishing composition had the pH shown in Table 1 and Table 2 below.

The pH of the polishing composition (liquid temperature: 25 ° C.) was confirmed by a pH meter (model number: LAQUA manufactured by HORIBA, Ltd.).

Further, for the zeta potential [mV] of the abrasive grains in the polishing composition, the polishing composition was subjected to ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., and the laser Doppler method (electrophoretic light) was performed using a flow cell at a measurement temperature of 25 ° C. It was calculated by the scattering measurement method) and the obtained data was analyzed by the Smoluchowski formula.

Details of the abrasive grains used in the preparation of each polishing composition and the polyalkylene glycol are shown below.

(Abrasion grain)
Abrasive grain 1: Silica with sulfonic acid fixed on the surface (average primary particle diameter 14 nm, average secondary particle diameter 34 nm, cocoon-shaped, unmodified (before modification, before organic acid fixation) silica is manufactured by the sol-gel method. Colloidal silica);
Abrasive grain 2: Silica with sulfonic acid fixed on the surface (average primary particle diameter 32 nm, average secondary particle diameter 69 nm, cocoon-shaped, unmodified (before modification, before organic acid fixation) silica is manufactured by the sol-gel method. Colloidal silica);
Abrasive grain 3: Silica with sulfonic acid fixed on the surface (average primary particle diameter 12 nm, average secondary particle diameter 53 nm, cocoon-shaped, unmodified (before modification, before organic acid fixation) silica is manufactured by the sodium silicate method. Colloidal silica);
Abrasive grain A: unmodified silica (average primary particle diameter 14 nm, average secondary particle diameter 34 nm, cocoon-shaped, colloidal silica produced by the sol-gel method);
(Polyalkylene glycol)
Polyethylene glycol 200 (PEG200) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 200, polyethylene glycol having a peak with a peak top molecular weight of 200);
Polyethylene glycol 600 (PEG600) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 600, polyethylene glycol having a peak with a peak top molecular weight of 600);
Polyethylene glycol 1000 (PEG1000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 1,000, polyethylene glycol having a peak with a peak top molecular weight of 1,000);
Polyethylene glycol 1540 (PEG1540) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 1,540, polyethylene glycol having a peak with a peak top molecular weight of 1,540);
-Polyethylene glycol 2000 (PEG2000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 2,000, polyethylene glycol having a peak with a peak top molecular weight of 2,000);
-Polyethylene glycol 4000 (PEG4000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 4,000, polyethylene glycol having a peak with a peak top molecular weight of 4,000);
-Polyethylene glycol 6000 (PEG6000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 6,000, polyethylene glycol having a peak with a peak top molecular weight of 6,000);
-Polyethylene glycol 8000 (PEG8000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 8,000, polyethylene glycol having a peak with a peak top molecular weight of 8,000);
Polyethylene Glycol 10000 (PEG10000) (manufactured by Alfa Aesar, product name Polyethylene glycol 10,000, polyethylene glycol having a peak with a peak top molecular weight of 10,000);
Polyethylene glycol 15000 (PEG15000) (polyethylene glycol having a peak with a peak top molecular weight of 15,000);
Polyethylene glycol 20000 (PEG20000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polyethylene glycol 20,000, polyethylene glycol having a peak with a peak top molecular weight of 20,000);
-Polypropylene glycol 400 (PPG400) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name polypropylene glycol, diol type, 400, polypropylene glycol having a peak with a peak top molecular weight of 400).

In addition, in Table 1 below and Table 2 below, for example, in the column of the type of "peak top molecular weight less than 1000 or EG" of the polishing composition 1, "PEG200 / PEG600" means that both PEG200 and PEG600 are used. Represents. Further, "0.2 / 0.4" in the column of the concentration (g / L) means that the concentration of PEG200 is 0.2 g / L and the concentration of PEG600 is 0.4 g / L. .. In addition, other types of combinations and concentration combinations are also described in the same manner.

<Evaluation of molecular weight distribution and peak top molecular weight in the molecular weight distribution>
The molecular weight distribution of each polyalkylene glycol used as the above raw material and the peak top molecular weight in the molecular weight distribution were measured by gel permeation chromatography (GPC).

In addition, the molecular weight distribution in terms of polyethylene glycol as a whole of the polyalkylene glycol contained in the polishing composition and the peak top molecular weight of the peak in the molecular weight distribution were measured by gel permeation chromatography (GPC).

The measurement conditions for the molecular weight distribution of polyalkylene glycol and the peak top molecular weight are as follows. Moreover, polyethylene glycol was used as a standard substance.

GPC device: manufactured by Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII)
Column: VP-ODS (manufactured by Shimadzu Corporation)
Mobile phase A: MeOH
B: 1% aqueous acetic acid flow rate: 1 mL / min
Detector: ELSD emp. 40 ° C, Gain 8, N2GAS 350kPa
Oven temperature: 40 ° C
Injection volume: 40 μl.

As a result of this measurement, the value of the peak top molecular weight of each peak in the molecular weight distribution of the polyalkylene glycol as a whole contained in the polishing composition is the peak top molecular weight of the peak of the molecular weight distribution of the raw material polyalkylene glycol. Was substantially the same as the value of.

<Polishing method>
Using each polishing composition prepared above, the surface of each polishing object was polished with the following equipment and conditions. Here, the polishing conditions and the objects to be polished are as follows.

(Polishing conditions)
Polishing machine: CMP single-sided polishing machine for 200 mm wafer Pad: Polyurethane pad Pressure: 3 psi (about 20.7 kPa)
Surface plate rotation speed: 90 rpm (1.5s ^-1 )
Flow rate of polishing composition: 130 ml / min
Polishing time: 1 minute Polishing target: 200 mm wafer (Poly-Si, SiN, TEOS-SiO)
Polycrystalline Silicon (Poly-Si): Manufactured by Low Pressure Chemical Vapor Deposition (LPCVD): Thickness 5,000 Å
Silicon Nitride (SiN): Manufactured by Low Pressure Chemical Vapor Deposition (LPCVD): Thickness 3,500 Å
Silicon oxide (TEOS-SiO) derived from tetraethyl orthosilicate (TEOS): manufactured by physical vapor deposition (PVD): 10,000 Å thick.

The polishing speed was evaluated by determining the film thickness before and after polishing with a light interference type film thickness measuring device and dividing the difference by the polishing time.

Regarding the step, the 8-inch Poly-Si pattern wafer having the following configuration is polished, and the part around the wiring part for the part where the line and space is 0.25 μm / 0.25 μm (hereinafter, also referred to as the wiring part). The step between the two was measured using an AFM (atomic force microscope).

≪8 inch Poly-Si pattern wafer≫
Specifications 1st layer: P-TEOS-SiO (plasma TEOS-SiO) Thickness 1,000Å
Second layer: Poly-Si thickness 500Å
3rd layer: 854 pattern + etching 4th layer: SiN Thickness 1,000Å.

Here, the erosion represents a phenomenon in which the Poly-Si portion of the wiring portion is dented as compared with the portion around the wiring portion. Erosion evaluated the step between the Poly-Si portion of the polished wiring portion and the periphery of the wiring portion.

Further, the dishing represents a phenomenon in which the SiN portion of the wiring portion is dented as compared with the portion around the wiring portion. For the dishing, the step between the SiN portion of the wiring portion after polishing and the periphery of the wiring portion was evaluated.

In this evaluation, it was judged that the higher the polishing rate of SiN, the more preferable.

Further, in this evaluation, the ratio of the polishing rate (Å / min) of SiN to the polishing rate (Å / min) of TEOS-SiO (selection ratio of SiN to TEOS-SiO: SiN / TEOS-SiO), and Poly-. The higher the ratio of the polishing rate (Å / min) of SiN to the polishing rate of Si (Å / min) (selection ratio of SiN to Poly-Si: SiN / Poly-Si) is preferable, and both are 25 or more. It was judged that the selection ratio was excellent.

In this evaluation, it was judged that the smaller the erosion and the dishing are, the more preferable, and that the erosion is 45 Å or less and the dishing is 25 Å or less, the step reduction effect is excellent.

The formulation and physical properties of each polishing composition are shown in Table 1 below and Table 2 below. The evaluation results of each polishing composition are shown in Table 3 below.

As shown in Tables 1 to 3 above, the polishing compositions according to the comparative examples have a low polishing rate of silicon nitride (SiN), a low selection ratio of SiN to TEOS-SiO, and a ratio to Poly-Si. It was confirmed that a sufficient effect could not be obtained because the selection ratio of SiN was low, the erosion was large, and the dishing was large.

On the other hand, in the polishing composition according to the present invention, the polishing rate of silicon nitride (SiN) is high, the selection ratio of SiN to TEOS-SiO and the selection ratio of SiN to Poly-Si are remarkably high, and erosion and dishing occur. It was confirmed that it was extremely small and was remarkably excellent in the step reduction effect.

Claims (14)

Silica with organic acid fixed on the surface and
With polyalkylene glycol
Contains,
The molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC) for the polyalkylene glycol has two or more peaks.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 1,000 or more and 6,000 or less.
At least one peak of the molecular weight distribution is a peak having a peak top molecular weight of 100 or more and 800 or less.
The polyalkylene glycol contains polyethylene glycol and
At least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol.
A polishing composition having a pH of 3 or more and 6 or less. At least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polyethylene glycol.
or,
The polyalkylene glycol further contains polypropylene glycol or polybutylene glycol, and at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polypropylene glycol or polybutylene glycol.
The polishing composition according to claim 1. The polishing composition according to claim 1 or 2, wherein the organic acid is a sulfonic acid or a carboxylic acid. The polishing composition according to any one of claims 1 to 3, wherein the silica having the organic acid immobilized on the surface has an average primary particle size of 10 nm or more and 50 nm or less. The polishing composition according to any one of claims 1 to 4, wherein the silica having the organic acid immobilized on the surface has an average secondary particle diameter of 20 nm or more and 100 nm or less. The silica for polishing according to any one of claims 1 to 5, wherein the silica before fixing the organic acid is colloidal silica produced by a sol-gel method or a sodium silicate method in the silica in which the organic acid is fixed on the surface. Composition. The polishing composition according to any one of claims 1 to 6, further comprising a polishing accelerator. The polishing composition according to any one of claims 1 to 7, further comprising a step improving agent. The polishing composition according to any one of claims 1 to 8, further comprising an acid. Any of claims 1 to 9 used for polishing an object to be polished containing a material having a silicon-nitrogen bond, and at least one of a material having a silicon-oxygen bond and a material having a silicon-silicon bond. The polishing composition according to item 1. Silica with organic acid fixed on the surface and
In the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC), polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less,
In the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC), polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less,
Have a mixing step of mixing,
A method for producing a polishing composition, which has a pH of 3 or more and 6 or less. Using the polishing composition according to any one of claims 1 to 10,
or,
A polishing composition is produced by the production method according to claim 11, and the polishing composition is used.
A polishing method for polishing an object to be polished. The polishing method according to claim 12, wherein the polishing object includes a material having a silicon-nitrogen bond, and at least one of a material having a silicon-oxygen bond and a material having a silicon-silicon bond. The object to be polished is a substrate, and a method for manufacturing a polished substrate, which comprises a step of polishing the object to be polished by the polishing method according to claim 12 or 13.