Polishing composition, production method of the same, polishing method, and manufacturing method of semiconductor substrate

Abstract

To provide means capable of improving an effect of inhibiting polishing of silicon nitride.SOLUTION: The present invention relates to a polishing composition containing cationically modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a group of a salt thereof, and water.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polishing composition, a method for producing the same, a polishing method, and a method for producing a semiconductor substrate. [Background technology]

[0002] In recent years, with the trend toward multilayer wiring on the surface of semiconductor substrates, a so-called chemical mechanical polishing (CMP) technique is used to polish and flatten semiconductor substrates when manufacturing devices. CMP is a method for flattening the surface of an object to be polished (object to be polished) such as a semiconductor substrate by using a polishing composition (slurry) containing abrasive grains such as silica, alumina, ceria, etc., an anticorrosive agent, a surfactant, etc. In this case, the object to be polished (object to be polished) is a film containing silicon, polysilicon, silicon oxide (silicon oxide), silicon nitride (silicon nitride), titanium nitride, titanium, tantalum nitride, tantalum, etc., wiring, plugs, etc. made of metals such as copper and tungsten, etc.

[0003] In the CMP technique, silicon nitride is used as a stopper film (etching mask), and in this case, it is preferable that the ratio of the polishing rate of materials other than silicon nitride (hereinafter, in this specification, also simply referred to as "other materials") to the polishing rate of silicon nitride (selectivity ratio of other materials to silicon nitride) is large. Regarding polishing of an object to be polished using silicon nitride as a stopper film, Patent Document 1 discloses a chemical mechanical polishing composition that is composed of silica, aminophosphonic acid, polysaccharide, tetraalkylammonium salt, bicarbonate, a compound containing an azole ring, potassium hydroxide as an optional component, and water, and has a pH of 7 to 11. Patent Document 1 also discloses that when polishing is performed using the chemical mechanical polishing composition at a high polishing pressure, the selectivity of polysilicon to silicon nitride, which is a stopper film, and the selectivity of polysilicon to silicon oxide, which is an insulating film, are improved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2014-505358 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the chemical mechanical polishing composition of Patent Document 1 has a problem that the selectivity of other materials to silicon nitride is insufficient because the effect of suppressing polishing of silicon nitride is insufficient, and there is also a problem that measures such as increasing the thickness of the silicon nitride film are required to account for the loss.

[0006] Therefore, an object of the present invention is to provide a means for improving the polishing suppression effect of silicon nitride. [Means for solving the problem]

[0007] One aspect of the present invention to solve the above problems is as follows: A polishing composition comprising cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt group, and water. Effect of the Invention

[0008] According to the present invention, a means is provided that can improve the polishing suppression effect of silicon nitride. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described. Note that the present invention is not limited to only the following embodiments. In addition, in this specification, the range "X to Y" means "X or more and Y or less". Furthermore, unless otherwise specified, the operation and measurement of physical properties are performed under the conditions of room temperature (range of 20°C to 25°C) and relative humidity of 40% RH to 50% RH.

[0010] <Polishing composition> One aspect of the present invention relates to a polishing composition comprising cation-modified silica particles, a non-aromatic bridged cyclic compound having an organic acid group or a salt group, and water.

[0011] The present inventors speculate that the mechanism by which the above problems can be solved is as follows.

[0012] The non-aromatic bridged cyclic compound having an organic acid group or a salt group is adsorbed to the silicon nitride film (silicon nitride surface) having a positive charge by electrostatic attraction, starting from the organic acid group or a salt group, which is an anionic functional group. At this time, the non-aromatic bridged cyclic compound having an organic acid group or a salt group strongly protects the silicon nitride film from the abrasive grains by suppressing the collision between the abrasive grains and the silicon nitride film with its bulky ring structure. This weakens the scraping action of the abrasive grains on the silicon nitride film. In addition, since the cation-modified silica particles have a positive charge and the silicon nitride film also has a positive charge, electrostatic repulsion occurs between them, weakening the scraping action and scraping frequency of the silicon nitride film of the abrasive grains. And, by combining the cation-modified silica particles and the non-aromatic bridged cyclic compound having an organic acid group or a salt group, the functions of both are improved synergistically, and the polishing suppression effect of the abrasive grains on the silicon nitride film is dramatically improved.

[0013] It should be noted that the above mechanism is based on speculation, and whether it is correct or not does not affect the technical scope of the present invention.

[0014] Hereinafter, each component that can be contained in the polishing composition, the object to be polished, and the like will be described.

[0015] (SiN polishing inhibitor) The polishing composition according to one embodiment of the present invention contains a compound that suppresses the polishing of silicon nitride (also referred to as "SiN polishing suppressor" in this specification). The SiN polishing suppressor is a non-aromatic bridged cyclic compound having an organic acid group or a salt group. As described above, the SiN polishing suppressor acts to suppress the polishing of silicon nitride. In addition, when polishing an object to be polished that further contains other materials (especially titanium nitride) in addition to silicon nitride, the polishing suppression effect of this silicon nitride acts to improve the selectivity of other materials to silicon nitride.

[0016] The adsorption of the SiN polishing inhibitor to the silicon nitride film can be confirmed by TOF-SIMS analysis.

[0017] In this specification, the non-aromatic bridged cyclic compound refers to a bridged compound that does not have an aromatic ring in the molecule and has a structure in which both ends of the linear structural portion of two or more substituents of one single ring structure are bonded, excluding a structure that shares one side (i.e., a condensed ring compound).The non-aromatic bridged cyclic compound is not particularly limited, and examples thereof include camphor, adamantane, and derivatives in which the hydrocarbon group that forms the ring in these molecular structures is replaced with other atoms or functional groups.

[0018] The organic acid group or its salt group is not particularly limited, but preferred examples include a carboxy group, a carboxy salt group, a sulfo group, a sulfo salt group, a phosphonic acid group, a phosphonic acid salt group, a phosphoric acid group, and a phosphoric acid salt group. That is, the non-aromatic bridged cyclic compound having an organic acid group or its salt group preferably has at least one selected from the group consisting of a carboxy group, a carboxy salt group, a sulfo group, a sulfo salt group, a phosphonic acid group, a phosphonic acid salt group, a phosphoric acid group, and a phosphoric acid salt group. In addition, the non-aromatic bridged cyclic compound having an organic acid group or its salt group more preferably has a carboxy group, a carboxy salt group, a sulfo group, or a sulfo salt group, more preferably has a carboxy group or a sulfo group, and particularly preferably has a sulfo group. These groups further improve the polishing suppression effect of silicon nitride. In addition, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved.

[0019] The non-aromatic bridged cyclic compound having an organic acid group or a salt group is not particularly limited, but from the viewpoint of further improving the polishing suppression effect on silicon nitride and from the viewpoint of high polishing rate for other materials, a compound represented by the following general formula 1 is preferable.

[0020] [ka]

[0021] In the above general formula 1, Z1 is CR1R1', C=O or O; Z2 is CR2R2', C=O or O; Z3 is CR3R3', C=O or O; Z4 is CR4R4', C=O or O; R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group (e.g., a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group), a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; When at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted hydrocarbon group (e.g., an unsubstituted alkyl group, an unsubstituted alkenyl group or an unsubstituted alkynyl group), an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; At least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 comprises an organic acid group or a salt group.

[0022] In the above general formula 1, it is preferable that at least one of Z1, Z2, Z3 and Z4 is C=O, it is more preferable that at least one of Z1 and Z3 is C=O, it is further preferable that either one of Z1 and Z3 is C=O, and it is particularly preferable that Z3 is C=O. In this case, the group other than C=O in Z1, Z2, Z3 and Z4 is preferably CRR' (hereinafter, R represents R1 to R4 corresponding to Z1 to Z4, respectively, and R' represents R1' to R4' corresponding to Z1 to Z4, respectively) or O, and it is more preferable that it is CRR'.

[0023] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, the halogen atom is not particularly limited, and examples thereof include F, Cl, Br and I.

[0024] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, examples of the hydrocarbon group include an alkyl group, an alkenyl group and an alkynyl group. Among these, an alkyl group is preferred.

[0025] The alkyl group may be linear, branched or cyclic. The alkyl group is not particularly limited, but may be, for example, an alkyl group having 1 to 12 carbon atoms. Among these, linear or branched alkyl groups having 1 to 5 carbon atoms are preferred, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and 2-methylbutyl groups. Among these, linear alkyl groups having 1 to 5 carbon atoms are preferred, and methyl, ethyl, n-propyl, and isopropyl groups are more preferred, and methyl or ethyl groups are even more preferred, with methyl being particularly preferred.

[0026] The alkenyl group may be linear, branched or cyclic.The alkenyl group is not particularly limited, but includes, for example, vinyl group, 2-propenyl group, 2-butenyl group, 3-butenyl group, 1-methyl-2-propenyl group, 2-methyl-2-propenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-methyl-2-butenyl group, 2-methyl-2-butenyl group, 3-methyl-2-butenyl group, 1-methyl-3-butenyl group, 2-methyl-3-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1,2-dimethyl-2-propenyl group, 1-ethyl-2-propenyl group, etc.

[0027] The alkynyl group may be linear, branched or cyclic. Examples of the alkynyl group include, but are not limited to, 2-butynyl, 3-pentynyl, hexynyl, heptynyl, octynyl and decynyl.

[0028] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, the alkoxy group is not particularly limited, but examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a t-pentoxy group, a 2-methylbutoxy group and the like.

[0029] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, the polyoxyalkylene group is not particularly limited, and examples thereof include a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group, a block polyoxyalkylene group of a polyoxyethylene group and a polyoxypropylene group, a random polyoxyalkylene group of a polyoxyethylene group and a polyoxypropylene group, a block polyoxyalkylene group of a polyoxyethylene group and a polyoxybutylene group, a random polyoxyalkylene group of a polyoxyethylene group and a polyoxybutylene group, and the like.

[0030] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, the organic acid group or the salt group is not particularly limited, but as described above, it is preferable that it is at least one selected from the group consisting of a carboxy group, a salt group of a carboxy group, a sulfo group, a salt group of a sulfo group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphoric acid group and a salt group of a phosphoric acid group. Among these, it is more preferable that it is a carboxy group, a salt group of a carboxy group, a sulfo group or a salt group of a sulfo group, further preferably a carboxy group or a sulfo group, and particularly preferably a sulfo group.

[0031] In the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted group, the halogen atoms, hydrocarbon groups (e.g., alkyl groups, alkenyl groups, alkynyl groups), alkoxy groups, polyoxyalkylene groups, organic acid groups or salt groups as the substituents are the same as those explained for these groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the above general formula 1, respectively.

[0032] In the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted hydrocarbon group (e.g., a substituted alkyl group, a substituted alkenyl group, a substituted alkynyl group), the substituents are preferably each independently a deuterium atom, a halogen atom, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof. Also, in the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted alkoxy group or a substituted polyoxyalkylene group, the substituents are preferably each independently a deuterium atom, a halogen atom, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof.

[0033] In the above general formula 1, it is preferable that at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof.Of these, it is more preferable that only one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof. In this case, the organic acid group or its salt group, or the alkyl group substituted with the organic acid group or its salt group, is more preferably a carboxy group or its salt group, a sulfo group or its salt group, a methyl group substituted with a carboxy group or its salt group, or a methyl group substituted with a sulfo group or its salt group, is particularly preferably a carboxy group or a methyl group substituted with a sulfo group, and is most preferably a methyl group substituted with a sulfo group. These groups further improve the polishing suppression effect of silicon nitride. In addition, when polishing an object to be polished that further contains other materials (especially titanium nitride) in addition to silicon nitride, the selectivity of other materials to silicon nitride is further improved.

[0034] In the above general formula 1, it is particularly preferable that R1, R1', R2, R2', R3, R3', R4 and R4' are each independently a hydrogen atom.

[0035] In the above general formula 1, R5 is preferably a hydrogen atom or a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group, even more preferably a substituted alkyl group, and particularly preferably an alkyl group substituted with an organic acid group or a salt thereof. In this case, the alkyl group substituted with an organic acid group or a salt thereof is preferably a methyl group substituted with a sulfo group or a salt thereof, and particularly preferably a methyl group substituted with a sulfo group.

[0036] In the above general formula 1, R6 is preferably a hydrogen atom, or an organic acid group or a salt thereof, more preferably a hydrogen atom, or a carboxy group or a salt thereof, even more preferably a hydrogen atom or a carboxy group, and particularly preferably a hydrogen atom.

[0037] In the above general formula 1, R7 and R8 are each preferably independently a substituted or unsubstituted alkyl group, more preferably an unsubstituted alkyl group, and particularly preferably a methyl group.

[0038] Preferable specific examples of the SiN polishing inhibitor include (+)-10-camphorsulfonic acid, camphanic acid, and ketopinic acid, etc. Among these, (+)-10-camphorsulfonic acid or camphanic acid is preferable, and (+)-10-camphorsulfonic acid is more preferable.

[0039] The SiN polishing suppressing agent may be used alone or in combination of two or more kinds. The SiN polishing suppressing agent may be a synthetic product or a commercially available product.

[0040] The amount (concentration) of the SiN polishing inhibitor is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, and particularly preferably 0.15% by mass or more, based on the total mass of the polishing composition. In this range, the effect of suppressing the polishing of silicon nitride is further improved. In addition, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved. In addition, the amount (concentration) of the SiN polishing inhibitor is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less, based on the total mass of the polishing composition. In this range, the effect of the SiN polishing inhibitor is further enhanced. The reason for this is presumed to be that the electrostatic repulsion between the abrasive grains and silicon nitride is better maintained because the electrical conductivity is not excessively high and the electric double layer of the abrasive grains and silicon nitride is not excessively compressed. In addition, within this range, better dispersion stability of the slurry is ensured.

[0041] Alternatively, the amount (concentration) of the SiN polishing inhibitor to be added is not particularly limited, but may be appropriately selected so that the pH value of the polishing composition is desired.In this case, it is preferable to add the amount so that the pH value of the polishing composition described later is preferable.In addition, when adopting such an amount (concentration), it is not particularly limited, but it is particularly preferable to adopt it when not using the pH adjuster described later.

[0042] (Abrasive grain) The polishing composition according to one embodiment of the present invention contains cation-modified silica particles as abrasive grains. Abrasive grains generally act to improve the polishing rate by mechanically polishing the object to be polished, but as described above, cation-modified silica particles suppress the polishing of silicon nitride. In addition, when polishing an object to be polished that further contains other materials (especially titanium nitride) in addition to silicon nitride, the abrasive grains act to improve the polishing rate of the other materials and improve the selectivity of the other materials to silicon nitride.

[0043] The type of silica particles used as the raw material for the cation-modified silica particles is not particularly limited, and includes fumed silica, colloidal silica, etc., but is preferably colloidal silica. Examples of methods for producing colloidal silica include the sodium silicate method and the sol-gel method. Colloidal silica produced by either method can be used suitably. However, from the viewpoint of reducing metal impurities, colloidal silica produced by the sol-gel method is preferred. This is because colloidal silica produced by the sol-gel method contains less metal impurities that have the property of diffusing in semiconductors and less corrosive ions such as chloride ions. The production of colloidal silica by the sol-gel method can be carried out using a conventionally known method. Specifically, colloidal silica can be obtained by using a hydrolyzable silicon compound (e.g., alkoxysilane or its derivative) as a raw material and carrying out a hydrolysis-condensation reaction.

[0044] The cation-modified silica particles may be appropriately selected from known ones and used. The cation-modified silica particles may be produced by a method appropriately selected from known production methods, and the cation-modified silica particles may be used.

[0045] The cation-modified silica particles are preferably cation-modified colloidal silica. As the colloidal silica having a cationic group (cation-modified colloidal silica), colloidal silica having an amino group fixed on the surface is preferably exemplified. As a method for producing colloidal silica having such a cationic group, there is a method of fixing a silane coupling agent having an amino group, such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, or aminobutyltriethoxysilane, on the surface of silica particles, as described in JP-A-2005-162533. This makes it possible to obtain colloidal silica having an amino group fixed on the surface (amino group-modified colloidal silica). These cation-modified colloidal silicas further improve the effect of suppressing the polishing of silicon nitride. In addition, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved.

[0046] The shape of the cation-modified silica particles is not particularly limited, and may be spherical or non-spherical.Specific examples of non-spherical shapes include polygonal prisms such as triangular prisms and square prisms, cylinders, bales in which the center of the cylinder is bulging more than the ends, donuts in which the center of the disk is penetrated, plates, so-called cocoon-shaped shapes with a constriction in the center, so-called association-type spheres in which a plurality of particles are integrated, so-called confetti-shaped shapes with a plurality of protrusions on the surface, rugby ball shapes, and various other shapes, and are not particularly limited.Among these, when polishing an object to be polished that further contains silicon oxide as another material, the cocoon-shaped shape is preferred from the viewpoint of suppressing the polishing rate of silicon oxide.

[0047] The average primary particle diameter of the cation-modified silica particles is not particularly limited, but is preferably 5 nm or more, more preferably 7 nm or more, even more preferably 10 nm or more, and particularly preferably 25 nm or more. In this range, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved. In addition, the average primary particle diameter of the cation-modified silica particles is not particularly limited, but is preferably 120 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. In this range, the polishing suppression effect of silicon nitride is further improved. The value of the average primary particle diameter of the cation-modified silica particles can be calculated based on the specific surface area (BET specific surface area) of the cation-modified silica particles measured by the BET method, assuming that the shape of the cation-modified silica particles is a true sphere. More specifically, the average primary particle size of the cation-modified silica particles can be calculated from the specific surface area of ​​the cation-modified silica particles measured by the BET method using a "Flow Sorb II 2300" manufactured by Micromeritics, and the density of the cation-modified silica particles.

[0048] The average secondary particle diameter of the cation-modified silica particles is not particularly limited, but is preferably 10 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, and particularly preferably 50 nm or more. In this range, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved. In addition, the average secondary particle diameter of the cation-modified silica particles is not particularly limited, but is preferably 250 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and particularly preferably 100 nm or less. In this range, the polishing suppression effect of silicon nitride is further improved. The value of the average secondary particle diameter of the cation-modified silica particles can be calculated by a dynamic light scattering method represented by a laser diffraction scattering method, for example, using a dynamic light scattering particle size / particle size distribution device UPA-UTI151 manufactured by Nikkiso Co., Ltd.

[0049] The degree of association of the cation-modified silica particles is not particularly limited, but is preferably 5 or less, more preferably 3 or less, and even more preferably 2.5 or less. In this range, the effect of suppressing the polishing of silicon nitride is further improved. In addition, the degree of association of the cation-modified silica particles is preferably 1 or more, and more preferably 1.2 or more. In this range, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved. The degree of association of the cation-modified silica particles is obtained by dividing the average secondary particle diameter of the cation-modified silica particles by the average primary particle diameter.

[0050] The number of silanol groups per unit surface area of ​​the cation-modified silica particles (hereinafter also referred to as "silanol group density") is not particularly limited, but is preferably 0 / nm 2 It is preferable that the number of particles is more than 0.2 particles / nm. 2 More preferably, it is 1 / nm 2 More preferably, it is 1.4 particles / nm 2 It is particularly preferable that the silanol group density of the cation-modified silica particles is 10 / nm or more. When the silanol group density is within this range, the dispersibility of the abrasive grains is improved, and when an object to be polished that contains other materials (particularly titanium nitride) in addition to silicon nitride is polished, the selectivity of the other materials to silicon nitride is further improved. In addition, the silanol group density of the cation-modified silica particles is 10 / nm or more. 2 It is preferable that the number of particles is 6 or less per nm. 2 More preferably, it is 4 / nm or less. 2 More preferably, it is 2 / nm or less. 2 It is particularly preferable that the silanol group density of the cation-modified silica particles is as follows: After each parameter is measured or calculated by the following measurement method or calculation method, the silanol group density of the cation-modified silica particles can be calculated by the following method.

[0051] In the formula below, C is the total mass of the cation-modified silica particles, and S is the BET specific surface area of ​​the cation-modified silica particles. First, 1.50 g of cation-modified silica particles as a solid content is collected in a 200 ml beaker, 100 ml of pure water is added to make a slurry, and then 30 g of sodium chloride is added to dissolve. Next, 1 N hydrochloric acid is added to adjust the pH of the slurry to about 3.0 to 3.5, and pure water is added until the slurry becomes 150 ml. This slurry is adjusted to pH 4.0 using an automatic titration device (manufactured by Hiranuma Sangyo Co., Ltd., COM-1700) at 25°C using 0.1 N sodium hydroxide, and the volume V [L] of the 0.1 N sodium hydroxide solution required to increase the pH from 4.0 to 9.0 by pH titration is measured. The silanol group density can be calculated by the formula below.

[0052]

number

[0053] In the above formula, ρ is the silanol group density (pcs / nm 2 ) ; c represents the concentration (mol / L) of the sodium hydroxide solution used in the titration; V represents the volume (L) of sodium hydroxide solution required to raise the pH from 4.0 to 9.0; N A represents the Avogadro constant (units / mol); C represents the total mass (solids) of the cation-modified silica particles (g); S is the weighted average of the BET specific surface area of ​​the cation-modified silica particles (nm 2 / g).

[0054] The BET specific surface area of ​​the cation-modified silica particles can be measured using "Flow Sorb II 2300" manufactured by Micromeritics.

[0055] The zeta potential of the cation-modified silica particles in the polishing composition is not particularly limited, but is preferably a positive value. In this range, the polishing suppression effect of silicon nitride is further improved. In addition, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved. The reason for this is presumed to be that the cation-modified silica particles have a stronger positive charge, and the electrostatic repulsion between the cation-modified silica particles and the silicon nitride film is stronger, so that the scraping action and scraping frequency of the silicon nitride film of the abrasive grains are weakened. From the same viewpoint, the zeta potential of the cation-modified silica particles in the polishing composition is generally a positive value, and the larger the value, the more preferable it is, so for example, more preferably 10 mV or more, even more preferably 20 mV or more, and particularly preferably 30 mV or more. In addition, the zeta potential of the cation-modified silica particles in the polishing composition is preferably, for example, 60 mV or less. The zeta potential of the cation-modified silica particles in the polishing composition can be calculated by subjecting the polishing composition to an ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., measuring the composition at a measurement temperature of 25°C using a flow cell by the laser Doppler method (electrophoretic light scattering measurement method), and analyzing the obtained data using the Smoluchowski formula.

[0056] The size (average primary particle size, average secondary particle size), degree of association, silanol group density, and zeta potential in the polishing composition of the cation-modified silica particles can be appropriately controlled by selecting the method for producing the cation-modified silica particles, etc. In particular, the silanol group density is preferably controlled by the conditions of heat treatment such as calcination.

[0057] The cation-modified silica particles may be used alone or in combination of two or more kinds.

[0058] The amount (concentration) of the cation-modified silica particles to be added is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more, based on the total mass of the polishing composition. In this range, when polishing an object to be polished that further contains other materials (especially titanium nitride) in addition to silicon nitride, the selectivity of the other materials to silicon nitride is further improved. In addition, the amount (concentration) of the cation-modified silica particles to be added is not particularly limited, but is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on the total mass of the polishing composition. In this range, the polishing suppression effect of silicon nitride is further improved.

[0059] The polishing composition according to one embodiment of the present invention may contain other abrasive grains in addition to the cation-modified silica grains. The other abrasive grains may be any of inorganic grains other than the cation-modified silica grains, organic grains, and organic-inorganic composite grains. Examples of inorganic grains other than the cation-modified silica grains include surface-unmodified silica grains, anion-modified silica grains, grains made of metal oxides such as alumina grains, ceria grains, and titania grains, silicon nitride grains, silicon carbide grains, and boron nitride grains. Examples of organic grains include polymethylmethacrylate (PMMA) grains.

[0060] However, in the polishing composition according to one embodiment of the present invention, the amount (concentration) of other abrasive grains added is preferably as small as possible, and it is particularly preferable that the polishing composition does not substantially contain other abrasive grains. In this specification, the term "does not substantially contain other abrasive grains" refers to the amount (concentration) of other abrasive grains added being less than 0.001% by mass relative to the total mass of the polishing composition.

[0061] (Silicon oxide polishing inhibitor) The polishing composition according to one embodiment of the present invention preferably further contains a compound that suppresses the polishing of silicon oxide (also referred to as a "silicon oxide polishing suppressor" in this specification). The silicon oxide polishing suppressor is a compound represented by the following general formula 2.

[0062] [ka]

[0063] In the above general formula 2, X1 is a CR 11 R 11 ' or C=O, X2 is a CR 12 R 12 ' or C=O, X3 is a CR 13 R 13 ' or C=O, X4 is a CR 14 R 14 ' or C=O, R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 each ' is independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxyhydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3:

[0064] [ka]

[0065] In the above general formula 3, R 15 is a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted hydrocarbon group; * is a bond bonded to the nitrogen atom (N) constituting the ring in the above general formula 2, R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R14 , R 14 ' and R 15 When at least one of is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group.

[0066] The silicon oxide polishing inhibitor acts to suppress the polishing of silicon oxide, which is another material. In addition, when polishing an object to be polished that contains, in addition to silicon oxide, other materials (especially titanium nitride), the inhibitor acts to improve the selectivity of the other materials to silicon oxide. The reason for this is unclear, but is speculated as follows. It has been confirmed that the silicon oxide polishing inhibitor is adsorbed to the SiO2 sensor by QCM (quartz crystal microbalance). From this, the silicon oxide polishing inhibitor is adsorbed to the silicon oxide film (silicon oxide surface) to suppress the collision between the abrasive grains and the silicon oxide film, thereby protecting the silicon oxide film from the abrasive grains. Note that this mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

[0067] In a preferred embodiment of the present invention, the polishing composition further comprises a silicon oxide polishing inhibitor in addition to the cation-modified silica particles and the above-mentioned SiN polishing inhibitor.The SiN polishing inhibitor acts on silicon nitride, and the silicon oxide polishing inhibitor acts on silicon oxide, and each of these functions is well performed, so that this polishing composition can improve the selectivity of other materials to silicon nitride and improve the selectivity of other materials other than silicon oxide to silicon oxide at the same time.

[0068] R in the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 ' and R in the above general formula 3 15In the above formula, the halogen atom is not particularly limited, and examples thereof include F, Cl, Br, and I.

[0069] R in the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 ' and R in the above general formula 3 15 In the above formula, the hydrocarbon group is not particularly limited, but examples thereof include an alkyl group, an alkenyl group, an alkynyl group, etc. The alkyl group, the alkenyl group, and the alkynyl group are not particularly limited, but examples thereof include the same groups as those mentioned in the explanation of the groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above formula 1.

[0070] R in the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 In the formula (1), the oxyhydrocarbon group is a group represented by "-OR" where R" represents a hydrocarbon group. The hydrocarbon group is R in the above general formula 2. 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 ' and R in the above general formula 3 15 This is similar to the explanation given in .

[0071] R in the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R13 ', R 14 and R 14 In ', the polyoxyalkylene group is not particularly limited, and examples thereof include the same ones as those exemplified in the polyoxyalkylene groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in general formula 1 above.

[0072] In the above general formula 2, R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 In the case where at least one of R 15 In the case where R is a substituted group, the halogen atom as the substituent is not particularly limited, and examples thereof include F, Cl, Br and I. In addition, the oxyhydrocarbon group and the polyoxyalkylene group as the substituent are each R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 The explanation of these groups is the same as that in '.

[0073] In the above general formula 2, R 10 is preferably a group represented by the above general formula 3. In this case, R 15 is preferably a substituted or unsubstituted hydrocarbon group, more preferably an unsubstituted hydrocarbon group, further preferably an unsubstituted alkyl group or an unsubstituted alkenyl group, even more preferably an unsubstituted alkyl group having 1 to 6 carbon atoms or an unsubstituted alkenyl group having 2 to 6 carbon atoms, and particularly preferably a methyl group or a vinyl group.

[0074] In the above general formula 2, R 11, R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 It is more preferable that all of the ' are hydrogen atoms.

[0075] Specific examples of silicon oxide polishing inhibitors are not particularly limited, but include, for example, 4-acetylmorpholine, 3-morpholinone, N-methyl-2-morpholinone, 4-vinyl-3-morpholinone, 4-acryloylmorpholine, 4-methacryloylmorpholine, etc. Among these, 4-acetylmorpholine and 4-acryloylmorpholine are preferred. From the viewpoint of improving the selectivity of other materials to silicon nitride, 4-acetylmorpholine is more preferred, and from the viewpoint of improving the selectivity of other materials to silicon oxide, 4-acryloylmorpholine is more preferred.

[0076] The silicon oxide polishing inhibitor may be used alone or in combination of two or more kinds. The silicon oxide polishing inhibitor may be a synthetic product or a commercially available product.

[0077] The amount (concentration) of the silicon oxide polishing inhibitor is not particularly limited, but is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, even more preferably 0.1 mass% or more, and particularly preferably 0.25 mass% or more, based on the total mass of the polishing composition. In this range, the effect of suppressing the polishing of silicon oxide is further improved. In addition, when polishing an object to be polished that further contains other materials (particularly titanium nitride) other than silicon oxide in addition to silicon oxide, the selectivity of other materials other than silicon oxide to silicon oxide is further improved. In addition, the amount (concentration) of the silicon oxide polishing inhibitor is not particularly limited, but is preferably 10 mass% or less, more preferably 5 mass% or less, even more preferably 1 mass% or less, and particularly preferably 0.5 mass% or less, based on the total mass of the polishing composition. In this range, the effect of the silicon oxide polishing inhibitor is further improved. This is presumably because the electrical conductivity is not excessively high and the electric double layer of the abrasive grains and silicon oxide is not excessively compressed, so that the electrostatic repulsion between the abrasive grains and silicon oxide is better maintained. In addition, within this range, better dispersion stability of the slurry is also ensured.

[0078] (Oxidizing agent) The polishing composition according to one embodiment of the present invention preferably further contains an oxidizing agent, which acts to improve the polishing characteristics by oxidizing the film surface of a material other than the silicon nitride film, such as increasing the polishing speed of the other material or improving the surface quality of the object to be polished after polishing.

[0079] The oxidizing agent is not particularly limited, but examples thereof include hydrogen peroxide, sodium peroxide, barium peroxide, ozone water, silver (II) salt, iron (III) salt, permanganic acid, chromic acid, dichromate, peroxodisulfuric acid, peroxolinic acid, peroxosulfuric acid, peroxoboric acid, performic acid, peracetic acid, perbenzoic acid, perphthalic acid, hypochlorous acid, hypobromous acid, hypoiodous acid, chloric acid, chlorous acid, perchloric acid, bromic acid, iodic acid, periodic acid, persulfuric acid, dichloroisocyanuric acid, and salts thereof. Among these, hydrogen peroxide is preferred from the viewpoint of handling and safety. The oxidizing agent can be used alone or in combination of two or more.

[0080] The amount (concentration) of the oxidizing agent to be added is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more, based on the total mass of the polishing composition. In this range, the oxidation reaction of materials other than the silicon nitride film proceeds more sufficiently, and the selectivity of other materials to silicon nitride is improved. In addition, the amount (concentration) of the oxidizing agent to be added is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on the total mass of the polishing composition. In this range, the effect of the decrease in abrasive grain concentration due to the addition of the oxidizing agent is smaller, the polishing rate of materials other than the silicon nitride film can be maintained better, and the selectivity of other materials to silicon nitride is improved.

[0081] (pH adjuster) The polishing composition according to one embodiment of the present invention preferably further contains a pH adjuster, which adjusts the pH of the polishing composition to an appropriate range, thereby improving the chemical polishing effect on the surface to be polished, thereby increasing the polishing rate, or improving the dispersion stability of the polishing composition.

[0082] In this specification, the above-mentioned SiN polishing inhibitor is not included in the pH adjuster.

[0083] The pH adjuster is not particularly limited as long as it is a compound that has pH adjusting function, and can use, for example, acid or basic compound.Here, basic compound refers to a compound that dissolves in water and has the function of increasing the pH of water, and acts to increase the pH of the polishing composition by adding it to the polishing composition.

[0084] The acid may be either an inorganic acid or an organic acid. The inorganic acid is not particularly limited, but examples thereof include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. The organic acid is not particularly limited, but examples thereof include carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid.

[0085] The basic compound is not particularly limited, but examples thereof include hydroxides of alkali metals or Group 2 elements, ammonia, etc. Specific examples of hydroxides of alkali metals include potassium hydroxide (KOH), sodium hydroxide (NaOH), etc. Specific examples of hydroxides of Group 2 elements include calcium hydroxide (Ca(OH)2).

[0086] Among these, inorganic acids or basic compounds are preferred from the viewpoint of adjusting the pH value to the optimum range described later. As the inorganic acid, nitric acid is more preferred. As the basic compound, an alkali metal or a hydroxide of a Group 2 element is more preferred, and an alkali metal hydroxide is even more preferred. As the pH adjuster, nitric acid or potassium hydroxide is particularly preferred, and potassium hydroxide is extremely preferred.

[0087] The pH adjusters may be used alone or in combination of two or more kinds.

[0088] The amount (concentration) of the pH adjuster to be added may be appropriately selected so as to give the desired pH value of the polishing composition, and it is preferable to add an amount so as to give a preferred pH value of the polishing composition described below.

[0089] (pH) The pH of the polishing composition according to one embodiment of the present invention is not particularly limited. However, the lower limit of the pH is preferably 1 or more, more preferably 1.5 or more, and even more preferably 2 or more. In this range, the polishing suppression effect of silicon nitride is further enhanced. The reason is presumed as follows. In this range, the electrical conductivity is not excessively high, and the electric double layer of the abrasive grains and silicon nitride is not excessively compressed. Therefore, the electrostatic repulsion between the abrasive grains and silicon nitride is better maintained. In addition, the possibility of deteriorating consumable members such as the polishing device and the polishing pad in contact with it is further reduced. In addition, the upper limit of the pH is preferably 12 or less. In this range, corrosion is less likely to occur, and application to polishing objects including various materials is possible. In addition, safety is further improved and handling is easier. And the upper limit of the pH is more preferably less than 7, even more preferably 5 or less, even more preferably 4 or less, particularly preferably less than 4, even more particularly preferably 3.5 or less, and extremely preferably 3 or less. In this range, the polishing suppression effect of silicon nitride is further enhanced. The reason for this is presumed to be as follows. When the pH is within the above range, the surface potential of silicon nitride becomes positive and the positive value becomes large. Generally, the zeta potential of the abrasive grains also becomes positive and the positive value becomes large. Therefore, the electrostatic repulsion between the abrasive grains and silicon nitride becomes stronger, and the scraping action of the abrasive grains becomes weaker. The pH value of the polishing composition can be evaluated with a pH meter (manufactured by Horiba Ltd., product name: LAQUA (registered trademark)).

[0090] (Electrical conductivity adjuster) The polishing composition according to one embodiment of the present invention may further contain an electrical conductivity adjuster. The electrical conductivity adjuster adjusts the electrical conductivity of the polishing composition to an appropriate range, thereby improving the effect of suppressing the removal rate of silicon nitride or improving the dispersion stability of the polishing composition.

[0091] The electrical conductivity adjuster is not particularly limited as long as it is a compound having an electrical conductivity adjusting function, and for example, a salt compound can be used.

[0092] Examples of salt compounds include acid salts and salts of basic compounds. Examples of acid salts include organic acid salts and inorganic acid salts. Examples of inorganic acid salts include, but are not limited to, nitrates such as potassium nitrate and ammonium nitrate, phosphates such as diammonium hydrogen phosphate and ammonium dihydrogen phosphate, and sulfates such as ammonium sulfate. Examples of salts of basic compounds include, but are not limited to, potassium chloride, sodium chloride, potassium bromide, potassium iodide, and ammonium citrate. The salt compounds may be used alone or in combination of two or more.

[0093] The amount (concentration) of the electrical conductivity adjuster to be added may be appropriately selected so as to obtain the desired electrical conductivity of the polishing composition, and it is preferable to add an amount so as to obtain a preferred electrical conductivity value of the polishing composition described below.

[0094] (Electrical Conductivity) The electrical conductivity (EC) of the polishing composition according to one embodiment of the present invention is not particularly limited. However, the lower limit of the electrical conductivity is preferably 30 μS / cm or more, more preferably 0.1 mS / cm or more, and even more preferably 0.6 mS / cm or more. In this range, the polishing suppression effect of silicon nitride is further enhanced. The reason for this is presumed to be that the electrostatic repulsion acting between the abrasive grains and the silicon nitride is maintained at a higher level at low electrical conductivity. In addition, the upper limit of the electrical conductivity is preferably less than 10 mS / cm. In this range, the dispersion stability of the polishing composition is further improved. Furthermore, the upper limit of the electrical conductivity is more preferably 2 mS / cm or less, and even more preferably 1 mS / cm or less. In this range, the polishing rate suppression effect of the silicon nitride film is further improved. The reason for this is presumed to be that the electrical conductivity does not increase excessively and the electrostatic repulsion between the abrasive grains and the silicon nitride film is not weakened. From these viewpoints, an example of a preferred range of electrical conductivity is 30 μS / cm or more and 2 mS / cm or less. The electrical conductivity of the polishing composition can be evaluated using a tabletop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71).

[0095] The electrical conductivity can be improved by, for example, increasing the amount of an acid, a basic compound, or a salt compound thereof. Specifically, the electrical conductivity may be controlled by the amount of each component other than the electrical conductivity regulator, or by further adding an electrical conductivity regulator.

[0096] (dispersion medium) The polishing composition according to one embodiment of the present invention further contains a dispersion medium (solvent). The dispersion medium contains water. The dispersion medium acts to disperse or dissolve each component.

[0097] The dispersion medium is not particularly limited as long as it contains water. The content of water in the dispersion medium is not particularly limited, but is preferably 50% by mass or more, more preferably 90% by mass or more, and even more preferably water alone, based on the total mass of the dispersion medium. From the viewpoint of preventing contamination of the object to be cleaned and inhibition of the action of other components, the water is preferably water that contains as few impurities as possible, and is preferably water with a total content of transition metal ions of 100 ppb or less. Here, the purity of the water can be increased by, for example, removing impurity ions using an ion exchange resin, removing foreign matter using a filter, distillation, or other operations. Specifically, it is preferable to use deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, or the like as the water.

[0098] In addition, the dispersion medium may be a mixed solvent of water and an organic solvent if the dispersibility or solubility of each component can be improved. The organic solvent is not particularly limited, and a known organic solvent can be used. When a mixed solvent of water and an organic solvent is used, it is preferable that the organic solvent is miscible with water. When an organic solvent is used, each component may be added to the mixed solvent after mixing water and an organic solvent to prepare a mixed solvent, or each component may be dispersed or dissolved in an organic solvent and then mixed with water. The organic solvent may be used alone or in combination of two or more kinds.

[0099] (Other ingredients) The polishing composition according to one embodiment of the present invention may further contain other components within a range that does not impair the effects of the present invention. The other components are not particularly limited, and may be appropriately selected from various components used in known polishing compositions, including, for example, a wetting agent, a surfactant, a chelating agent, a preservative, an antifungal agent, a dissolved gas, a reducing agent, etc.

[0100] (Object to be polished) The polishing composition according to one embodiment of the present invention is not particularly limited, and can be applied to known polishing objects used in the CMP field.Therefore, the form of the polishing object is not particularly limited, but is preferably a layer that is a flat plate-like member, more preferably a substrate that includes the layer, and even more preferably a semiconductor substrate.For example, the substrate can be a single layer, or a substrate that includes a layer to be polished and other layers (for example, a support layer or other functional layers).

[0101] From the viewpoint that the effect of the present invention is more prominent, it is particularly preferable that the surface of the object to be polished contains silicon nitride. That is, the polishing composition according to one embodiment of the present invention is preferably used to polish an object to be polished that contains silicon nitride. In addition, it is preferable that the surface of the object to be polished contains other materials in addition to silicon nitride. This is because the object to be polished according to one embodiment of the present invention has a high polishing suppression effect on silicon nitride while showing a high polishing rate on other materials, so that a selectivity of other materials to silicon nitride can be obtained. The other materials are not particularly limited, but are preferably, for example, the object to be polished further contains a silicon-containing material other than silicon nitride, or a component containing a metal, a metal oxide, a metal nitride, or the like.

[0102] Examples of silicon-containing materials other than silicon nitride include, but are not limited to, materials having silicon-oxygen bonds (e.g., silicon oxide, etc.), materials having silicon-silicon bonds (e.g., polysilicon, etc.), and materials having silicon-nitrogen bonds other than silicon nitride. Examples of materials having silicon-oxygen bonds include, but are not limited to, silicon oxide, BD (black diamond: SiOCH), FSG (fluorosilicate glass), HSQ (hydrogen silsesquioxane), CYCLOTENE, SiLK, MSQ (methyl silsesquioxane), and the like. Examples of polishing objects having silicon-silicon bonds include, but are not limited to, polycrystalline silicon (polysilicon, Poly-Si), amorphous silicon, single crystal silicon, n-type doped single crystal silicon, p-type doped single crystal silicon, Si-based alloys such as SiGe, and the like. Examples of materials having silicon-nitrogen bonds other than silicon nitride include, but are not limited to, silicon carbonitride (SiCN), and the like. Among these, from the viewpoint of being polished at a higher polishing rate by the polishing object according to one embodiment of the present invention and further improving the selectivity ratio of other materials to silicon nitride, a material having a silicon-silicon bond is preferred, and polysilicon is more preferred. Furthermore, among these, when the polishing composition further contains the above-mentioned silicon oxide polishing inhibitor, a material having a silicon-oxygen bond is preferred, and silicon oxide is more preferred. This is because both the effect of improving the selectivity ratio of other materials to silicon nitride and the effect of improving the selectivity of materials other than silicon oxide to silicon oxide are achieved. In addition, the film containing silicon oxide is not particularly limited, and examples thereof include TEOS (Tetraethyl Orthosilicate) type silicon oxide (also referred to as "TEOS-SiO2" in this specification) film generated using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma) film, USG (Undoped Silicate Glass) film, PSG (Phosphorus Silicate Examples of the silicon oxide include a silicon nitride (BOG) film, a BPSG (Boron-Phospho Silicate Glass) film, and a RTO (Rapid Thermal Oxidation) film. The silicon oxide is particularly preferably TEOS-SiO2. Therefore, the object to be polished is particularly preferably an object to be polished that further contains silicon oxide (preferably TEOS-SiO2) in addition to silicon nitride.

[0103] In addition, the metal is not particularly limited, but examples thereof include copper, aluminum, hafnium, cobalt, nickel, titanium, tungsten, and alloys thereof. The metal oxide is not particularly limited, but examples thereof include alumina. The metal nitride is not particularly limited, but examples thereof include titanium nitride, tantalum nitride, and the like. Among these, from the viewpoint of being polished at a higher polishing rate by the polishing object according to one embodiment of the present invention and further improving the selectivity of the other material to silicon nitride, the other material is preferably a metal nitride, and more preferably titanium nitride. Therefore, it is particularly preferable that the polishing object further contains titanium nitride in addition to silicon nitride.

[0104] For these reasons, it is particularly preferable that the object to be polished further contains silicon oxide (preferably TEOS-SiO2) and titanium nitride in addition to silicon nitride.

[0105] (Selectivity of other materials to silicon nitride) In the polishing method using the polishing composition according to one embodiment of the present invention, when polishing an object to be polished that further contains other materials in addition to silicon nitride, the selectivity of the other materials to silicon nitride is not particularly limited, but is preferably higher.For example, when the other materials are titanium nitride, the selectivity of titanium nitride to silicon nitride is not particularly limited, but is preferably 40 or more, more preferably 50 or more, more preferably 70 or more, even more preferably 90 or more, particularly preferably 100 or more, even more particularly preferably 110 or more, extremely preferably 150 or more, and most preferably 180 or more.In addition, for example, when the other materials are silicon oxide, the selectivity of titanium nitride to silicon oxide is not particularly limited, but is preferably more than 15, more preferably 20 or more, and even more preferably 25 or more.The selectivity of the other materials to silicon nitride can be calculated by dividing the polishing speed of the other materials by the polishing speed of silicon nitride.

[0106] <Method of manufacturing the polishing composition> Another aspect of the present invention relates to a method for producing a polishing composition, comprising mixing cation-modified silica particles, a non-aromatic bridged cyclic compound having an organic acid group or a salt group, and water.

[0107] In addition, in the method for producing a polishing composition according to one embodiment of the present invention, the above-described silicon oxide polishing inhibitor and other components may be further mixed in. Thus, a preferred embodiment of the present invention is a method for producing a polishing composition that further includes mixing a compound represented by the above general formula 2.

[0108] The mixing method for mixing each component is not particularly limited, and a known method can be used as appropriate. The mixing temperature is not particularly limited, but is generally preferably 10 to 40°C, and may be heated to increase the dissolution rate. The mixing time is also not particularly limited.

[0109] In addition, the preferred aspects (type, characteristics, structure, amount added, etc.) of each component in the method for producing a polishing composition are the same as those of each component in the above-mentioned polishing composition. In addition, the preferred characteristics and other various features of the produced polishing composition are the same as those in the above-mentioned polishing composition.

[0110] <Polishing method> Another embodiment of the present invention relates to a polishing method, comprising polishing an object to be polished by using the above polishing composition or by producing a polishing composition by the above production method, and using the polishing composition thus produced.

[0111] The object to be polished in the polishing method is the same as that described above for the polishing composition.

[0112] The polishing device and polishing conditions are not particularly limited, and known devices and conditions can be appropriately used.

[0113] The polishing device may be a general polishing device equipped with a holder for holding the object to be polished, a motor capable of changing the rotation speed, and a polishing platen to which a polishing pad (polishing cloth) can be attached. Either a single-sided polishing device or a double-sided polishing device may be used as the polishing device. As the polishing pad, general nonwoven fabric, polyurethane, porous fluororesin, etc. may be used without any particular restrictions. The polishing pad is preferably provided with grooves for collecting the polishing liquid.

[0114] The polishing conditions are not particularly limited, and appropriate conditions can be appropriately set according to the characteristics of the polishing composition and the object to be polished. The polishing load (polishing pressure, processing pressure) is not particularly limited, but generally, it is preferably 0.1 psi or more and 10 psi or less per unit area, more preferably 0.5 psi or more and 8 psi or less, and even more preferably 1 psi or more and 6 psi or less. In this range, it is possible to obtain a high polishing rate while suppressing the substrate damage caused by the load and the occurrence of defects such as scratches on the surface. The rotation speed of the platen and the carrier are not particularly limited, but generally, it is preferably 10 rpm or more and 500 rpm or less, more preferably 20 rpm or more and 300 rpm or less, and even more preferably 30 rpm or more and 200 rpm or less. The method of supplying the polishing composition is not particularly limited, and a method of continuously supplying the composition with a pump or the like (flowing) may be adopted. The supply amount of the polishing composition (flow rate of the polishing composition) may be a supply amount that covers the entire object to be polished, and is not particularly limited, but generally, it is preferably 100 mL / min or more and 5000 mL / min or less. The polishing time is not particularly limited and may be appropriately set so as to obtain the desired polishing result, but is generally preferably 5 seconds or more and 180 seconds or less. In addition, the polishing is preferably performed using in-situ dressing. Here, in-situ dressing refers to a technique of polishing and dressing the pad. In-situ dressing can further improve the uniformity of the polishing rate relative to the polishing time and further improve the controllability of polishing. As the in-situ dressing member, it is preferable to use a conditioner such as a diamond dresser.

[0115] After polishing, the polished object may be washed with water and then dried on the surface by using a spin dryer or air blower to remove water droplets adhering to the surface.

[0116] In the polishing method according to one embodiment of the present invention, when polishing the object to be polished that further contains other materials in addition to silicon nitride, the selectivity of other materials to silicon nitride is not particularly limited, but is preferably higher.The preferred range of the selectivity of titanium nitride to silicon nitride is the same as that described above for the polishing composition.The preferred range of the selectivity of titanium nitride to silicon oxide is the same as that described above for the polishing composition.

[0117] <Method of manufacturing semiconductor substrate> Another embodiment of the present invention relates to a method for producing a semiconductor substrate, comprising a step (polishing step) of polishing a substrate material, the substrate material being an object to be polished, by the above-mentioned polishing method. That is, this embodiment is a method for producing a semiconductor substrate, the method comprising polishing a substrate material, the object to be polished containing titanium nitride, using the above-mentioned polishing composition, or producing a polishing composition by the above-mentioned production method, and using the produced polishing composition.

[0118] In addition, in the manufacturing method, for other steps, steps that can be adopted in known manufacturing methods for semiconductor substrates can be appropriately adopted.

[0119] Although the embodiments of the present invention have been described in detail, it is apparent that the same are illustrative and exemplary, not restrictive, and the scope of the present invention should be interpreted by the appended claims.

[0120] The present invention encompasses, but is not limited to, the following aspects and configurations: 1. A polishing composition comprising cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt group, and water; 2. The polishing composition according to 1 above, wherein the non-aromatic bridged cyclic compound having an organic acid group or a salt group thereof is a compound represented by General Formula 1 above; 3. The polishing composition according to 2 above, wherein in General Formula 1, at least one of Z1, Z2, Z3 and Z4 is C=O; 4. The polishing composition according to 2. or 3. above, wherein in General Formula 1, at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is an organic acid group or a salt group thereof, or an alkyl group substituted with an organic acid group or a salt group thereof; 5. The polishing composition according to any one of 1. to 4. above, wherein the organic acid group or the salt group thereof is at least one selected from the group consisting of a carboxy group, a salt group of a carboxy group, a sulfo group, a salt group of a sulfo group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphoric acid group, and a salt group of a phosphoric acid group; 6. The polishing composition according to any one of 1. to 5. above, wherein the zeta potential of the cation-modified silica particles is a positive value; 7. The polishing composition according to any one of 1. to 6. above, further comprising a compound represented by General Formula 2 above; 8. The polishing composition according to any one of 1. to 7. above, further comprising an oxidizing agent; 9. The polishing composition according to any one of 1. to 8. above, which has a pH of less than 7; 10. The polishing composition according to any one of 1 to 9 above, which has an electrical conductivity of 30 μS / cm or more and 2 mS / cm or less; 11. The polishing composition according to any one of 1. to 10. above, which is used for polishing an object to be polished containing silicon nitride; 12. The polishing composition according to 11 above, which is used for polishing an object to be polished, further comprising titanium nitride; 13. The polishing composition according to 11 or 12 above, which is used for polishing an object to be polished further containing silicon oxide; 14. A method for producing a polishing composition, comprising mixing cation-modified silica particles, a non-aromatic bridged cyclic compound having an organic acid group or a salt group, and water; 15. A method for producing the polishing composition according to the above item 14, which comprises further mixing a compound represented by the above general formula 2; 16. Using the polishing composition according to any one of 1. to 13. above, or A polishing composition is produced by the production method described in 14. or 15. above, and the produced polishing composition is used to A method for polishing an object to be polished; 17. A method for producing a semiconductor substrate, comprising polishing a substrate material by the polishing method described in 16 above, wherein the object to be polished is a substrate material. EXAMPLES

[0121] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were performed under the conditions of room temperature (25°C) / relative humidity 40-50%RH.

[0122] <Preparation of polishing composition 1> (Polishing composition 1) Colloidal silica A (average primary particle size 35 nm; average secondary particle size 70 nm; silanol group density 1.5 / nm), which is colloidal silica with amino groups fixed on the surface, was used as an abrasive in pure water as a dispersion medium. 2 (degree of association: 2.0), (+)-10-camphorsulfonic acid as a SiN polishing suppressor, hydrogen peroxide as an oxidizing agent, and nitric acid as a pH adjuster were added to prepare Polishing Composition 1.

[0123] Here, the amount of colloidal silica A added as an abrasive grain was 3 mass% relative to the polishing composition prepared. The amount of (+)-10-camphorsulfonic acid added as an SiN polishing inhibitor was 0.05 mass% relative to the polishing composition prepared. The amount of hydrogen peroxide added as an oxidizing agent was 0.12 mass% relative to the polishing composition prepared. Here, hydrogen peroxide was added using a 31 mass% concentration hydrogen peroxide aqueous solution, and the amount of hydrogen peroxide contained therein was added to achieve the above-mentioned amount. The amount of nitric acid added as a pH adjuster was an amount such that the pH of the polishing composition prepared was 3.0. Here, the pH of the polishing composition 1 (liquid temperature: 25°C) was measured using a pH meter (manufactured by Horiba, Ltd., model number: LAQUA (registered trademark)).

[0124] The electrical conductivity (EC) of the polishing composition 1 prepared above was measured. The electrical conductivity of the polishing composition 1 (liquid temperature: 25°C) was measured using a tabletop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71). The electrical conductivity (EC) of the polishing composition 1 was 0.69 mS / cm.

[0125] Furthermore, the zeta potential of the abrasive grains in the polishing composition 1 prepared above was measured. First, the polishing composition was provided to an ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., and measurement was performed by a laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C. Then, the obtained data was analyzed by the Smoluchowski formula to calculate the zeta potential (mV) of the abrasive grains in the polishing composition. The zeta potential of the abrasive grains in the polishing composition 1 was 40 mV.

[0126] (Polishing composition 2-12) Each polishing composition was prepared in the same manner as in the preparation of Polishing Composition 1, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 1 below. Here, in the preparation of each polishing composition, the amount of pH adjuster added is an amount that makes the pH of the prepared polishing composition have the value in Table 1 below. The pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as in Polishing Composition 1.

[0127] (Polishing Compositions 13 and 14) Each polishing composition was prepared in the same manner as in the preparation of Polishing Composition 1, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 1 below. Here, the abrasive grains used were colloidal silica B (average primary particle size 13.8 nm; average secondary particle size 33 nm; silanol group density 2.2 / nm), which is colloidal silica with sulfo groups fixed to the surface. 2 The pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as in Polishing Composition 1.

[0128] <Polishing method 1> (Polishing equipment and polishing conditions) Using each of the polishing compositions prepared above, the surface of the object to be polished was polished with the following equipment and conditions. The objects to be polished were a TiN blanket wafer, which is a TiN film (titanium nitride film) having a thickness of 2500 Å formed on the surface of a substrate, and a SiN blanket wafer, which is a SiN film (silicon nitride film) having a thickness of 2000 Å formed on the surface of a substrate: [Polishing Equipment and Polishing Conditions] Polishing device: EJ-380IN-CH (Engis Japan Co., Ltd.) Polishing pad: IC1000 (manufactured by Nitta Haas Corporation (now Nitta DuPont Corporation)) Polishing pressure (processing pressure): 3.43 psi (1 psi = 6894.76 Pa) Rotation speed of polishing plate: 60 rpm (60 rpm = 1 s -1 is) Supply rate of polishing composition: 100 mL / min Polishing time: 60sec Conditioner (In-situ dressing component): Diamond dresser (SDT-100, manufactured by Noritake Co., Ltd.).

[0129] <Evaluation 1> (Measurement of polishing speed) The above-mentioned objects to be polished were polished using each polishing composition, and the polishing speed (Å / min) of the TiN film and the polishing speed (Å / min) of the SiN film were measured. The polishing speed of the TiN film was obtained by dividing the difference in thickness (Å) of the TiN blanket wafer before and after polishing, measured using a sheet resistance measuring device based on the principle of the DC four-point probe method, by the polishing time (min). The polishing speed of the SiN film was obtained by dividing the difference in thickness (Å) of the SiN blanket wafer before and after polishing, measured using an optical interference film thickness measuring device (Filmetrics Inc.: Model Filmetrics F50), by the polishing time (min). Note that 1Å=0.1 nm. The evaluation results are shown in Table 2 below.

[0130] [Table 1]

[0131] [Table 2]

[0132] From the results of Table 1 and Table 2, it was confirmed that the polishing compositions 1 to 3, 11 and 12 according to the examples, which contain cation-modified silica particles and the SiN polishing inhibitor of the present invention, can significantly suppress the polishing of SiN film. It was also confirmed that the selectivity of TiN film to SiN film can be significantly increased while maintaining a high polishing rate of TiN film. From these results, it can be seen that the polishing compositions 1 to 3, 11 and 12 according to the examples are particularly suitable for polishing an object further containing titanium nitride in addition to silicon nitride.

[0133] On the other hand, it was confirmed that the polishing compositions 4 to 6 and 8 according to the comparative examples that do not contain a SiN polishing inhibitor, the polishing compositions 7, 9 and 10 according to the comparative examples that contain a comparative compound with a structure different from that of the SiN polishing inhibitor of the present invention, the polishing composition 14 according to the comparative example that contains anion-modified silica particles instead of cation-modified silica particles, and the polishing composition 13 according to the comparative example that contains anion-modified silica particles instead of cation-modified silica particles and does not contain a SiN polishing inhibitor, have inferior polishing inhibition effect for SiN film compared with the polishing compositions 1 to 3, 11 and 12 according to the examples. And as a result, it was confirmed that the selectivity of TiN film to SiN film is also low.

[0134] <Preparation of polishing composition 2> (Polishing composition 15) Colloidal silica C (average primary particle size: 23 nm; average secondary particle size: 50 nm; silanol group density: 3.6 / nm), which is colloidal silica with amino groups fixed on the surface, was used as an abrasive in pure water as a dispersion medium. 2 (degree of association 2.2, cocoon-shaped shape), (+)-10-camphorsulfonic acid as a SiN polishing inhibitor, 4-acetylmorpholine as a silicon oxide polishing inhibitor, and hydrogen peroxide as an oxidizing agent were added to prepare Polishing Composition 15.

[0135] Here, the amount of colloidal silica C added as an abrasive grain was 1.8% by mass relative to the polishing composition prepared. The amount of (+)-10-camphorsulfonic acid added as an SiN polishing inhibitor was an amount that gave the polishing composition a pH of 3.0. The amount of 4-acetylmorpholine added as a silicon oxide polishing inhibitor was 0.13% by mass relative to the polishing composition prepared. The amount of hydrogen peroxide added as an oxidizing agent was 0.09% by mass relative to the polishing composition prepared. Here, hydrogen peroxide was added using a 31% by mass concentration hydrogen peroxide aqueous solution, and the amount of hydrogen peroxide contained therein was added to give the above-mentioned amount. Here, the pH of the polishing composition 15 (liquid temperature: 25° C.) was measured using a pH meter (manufactured by Horiba, Ltd., model number: LAQUA (registered trademark)).

[0136] The electrical conductivity (EC) of the polishing composition 15 prepared above was measured. The electrical conductivity of the polishing composition 15 (liquid temperature: 25° C.) was measured using a tabletop electrical conductivity meter (manufactured by Horiba, Ltd. The electrical conductivity (EC) of Polishing Composition 15 was measured using a polishing polishing agent (model number: DS-71). The electrical conductivity (EC) of Polishing Composition 15 was 0.6 mS / cm.

[0137] Furthermore, the zeta potential of the abrasive grains in the polishing composition 15 prepared above was measured. First, the polishing composition was provided to an ELS-Z2 manufactured by Otsuka Electronics Co., Ltd., and measurement was performed by a laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C. Then, the obtained data was analyzed by the Smoluchowski formula to calculate the zeta potential (mV) of the abrasive grains in the polishing composition. The zeta potential of the abrasive grains in the polishing composition 15 was 21 mV.

[0138] (Polishing composition 16-18) Each polishing composition was prepared in the same manner as in the preparation of Polishing Composition 15, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 3 below. Here, in the preparation of each polishing composition, the amount of (+)-10-camphorsulfonic acid added as a SiN polishing inhibitor was an amount that would give the polishing composition prepared a pH value of Table 3 below. The pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as in Polishing Composition 15.

[0139] (Polishing composition 19) Polishing composition 19 was prepared in the same manner as in the preparation of polishing composition 15, except that (+)-10-camphorsulfonic acid as a SiN polishing inhibitor was not added, and nitric acid as a pH adjuster was added in an amount that would make the pH of the prepared polishing composition 3.0. The pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as in the preparation of polishing composition 15.

[0140] <Polishing method 2> (Polishing equipment and polishing conditions) Using each of the polishing compositions prepared above, the surface of the object to be polished was polished with the following equipment and conditions. The objects to be polished were a TiN blanket wafer, which is a TiN film (titanium nitride film) with a thickness of 2500 Å formed on the surface of a substrate, a SiN blanket wafer, which is a SiN film (silicon nitride film) with a thickness of 2000 Å formed on the surface of a substrate, and a TEOS-SiO2 blanket wafer, which is a TEOS-SiO2 film with a thickness of 10,000 Å formed on the surface of a substrate. The size of these blanket wafers was 300 mm in diameter (12 inch size): [Polishing Equipment and Polishing Conditions] Polishing device: Single-sided polishing device FREX300E (manufactured by Ebara Corporation) Polishing pad: IC1000 (manufactured by Nitta Haas Corporation (now Nitta DuPont Corporation)) Polishing pressure (processing pressure): 4.0 psi (1 psi = 6894.76 Pa) Rotation speed of polishing plate: 110 rpm (60 rpm = 1 s -1 is) Supply rate of polishing composition: 250 mL / min Polishing time: 60sec Conditioner (In-situ dressing component): Diamond dresser (SDT-100, manufactured by Noritake Co., Ltd.).

[0141] <Evaluation 2> (Measurement of polishing speed) The above objects were polished using each polishing composition, and the polishing rates (Å / min) of TiN film, SiN film, and TEOS-SiO2 film were measured. The polishing rate of TiN film was determined by dividing the difference in thickness (Å) of TiN blanket wafer before and after polishing measured using a sheet resistance measuring device based on the DC 4-probe method by the polishing time (min). The polishing rate of SiN film was determined by dividing the difference in thickness (Å) of SiN blanket wafer before and after polishing measured using an optical interference film thickness measuring device (Filmetrics Inc.: Model Filmetrics F50) by the polishing time (min). The polishing rate of TEOS-SiO2 film was determined by dividing the difference in thickness (Å) of TEOS blanket wafer before and after polishing measured using an optical interference film thickness measuring device (KLA-Tencor Inc.: ASET-f5x) by the polishing time (min). Note that 1 Å=0.1 nm. The evaluation results are shown in Table 4 below.

[0142] (Stability of Polishing Composition) The polishing compositions 15 to 19 prepared above were visually checked for the presence or absence of precipitation of abrasive grains immediately after preparation (10 minutes after preparation). In addition, the compositions were left to stand in a thermostatic storage cabinet at 25°C, and the presence or absence of precipitation of abrasive grains was visually checked after 3 months. The evaluation results are shown in Table 4 below.

[0143] [Table 3]

[0144] [Table 4]

[0145] From the results of Tables 3 and 4, it was confirmed that the polishing compositions 15 to 18 according to the examples, which contain cation-modified silica particles and the SiN polishing inhibitor of the present invention, can significantly suppress the polishing of the SiN film. It was also confirmed that the selectivity of the TiN film to the SiN film can be significantly increased while maintaining a high polishing rate of the TiN film. From these results, it can be seen that the polishing compositions 15 to 18 according to the examples are particularly suitable for polishing an object further containing titanium nitride in addition to silicon nitride. It was also confirmed that these polishing compositions have excellent stability.

[0146] Furthermore, it was confirmed that the polishing compositions 15 to 17 according to the examples, which contain cation-modified silica particles, the SiN polishing inhibitor of the present invention, and the silicon oxide polishing inhibitor of the present invention, can significantly suppress the polishing of the SiN film while also significantly suppressing the polishing of the silicon oxide film. It was also confirmed that the selectivity of the TiN film to the silicon oxide film can be significantly increased in addition to the selectivity of the TiN film to the SiN film while maintaining a high polishing rate of the TiN film. From these results, it can be seen that the polishing compositions 15 to 17 according to the examples are particularly suitable for polishing an object to be polished that further contains titanium nitride in addition to silicon oxide. It can also be seen that the polishing compositions 15 to 17 according to the examples are particularly suitable for polishing an object to be polished that further contains silicon oxide and titanium nitride in addition to silicon nitride.

[0147] On the other hand, it was confirmed that the polishing composition 19 according to the comparative example, which does not contain a SiN polishing inhibitor, has an inferior effect of suppressing polishing of the SiN film, compared with the polishing compositions 15 to 18 according to the examples. As a result, it was confirmed that the selectivity of the TiN film to the SiN film is also low.

Claims

1. A method for producing a cation-modified silica particle, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group, and water, The non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is represented by the following general formula 1: The concentration of the cation-modified silica particles is 1.8% by mass or more and 10% by mass or less, based on the total mass of the polishing composition; The concentration of the non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is 0.05 mass% or more and 0.5 mass% or less, based on the total mass of the polishing composition. Polishing composition: 【Chemistry 1】 In the above general formula 1, Z １ is CR １ R １ ', C=O or O, Z ２ is CR ２ R ２ ', C=O or O, Z ３ is CR ３ R ３ ', C=O or O, Z ４ is CR ４ R ４ ', C=O or O, R １ , R １ ', R ２ , R ２ ', R ３ , R ３ ', R ４ , R ４ ', R ５ , R ６ , R ７ and R ８ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; The R １ , the R １ ', the R ２ , the R ２ ', the R ３ , the R ３ ', the R ４ , the R ４ ', the R ５ , the R ６ , the R ７ and the R ８ when at least one of the groups is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; The R １ , the R １ ', the R ２ , the R ２ ', the R ３ , the R ３ ', the R ４ , the R ４ ', the R ５ , the R ６ , the R ７ and the R ８ At least one of the groups contains an organic acid group or a salt thereof.

2. The polishing composition according to claim 1 , which is for polishing an object containing silicon oxide.

3. The polishing composition according to claim 1 or 2, further comprising a silicon oxide polishing inhibitor.

4. 4. The polishing composition according to claim 3, wherein the silicon oxide polishing inhibitor comprises at least one compound selected from the group consisting of 4-acetylmorpholine and 4-acryloylmorpholine.

5. 5. The polishing composition according to claim 1, having an electrical conductivity of 0.79 mS / cm or more and less than 10 mS / cm.

6. 6. The polishing composition according to claim 1, wherein the zeta potential of the cation-modified silica particles in the polishing composition is 10 mV or more and 22 mV or less.

7. The polishing composition according to any one of claims 1 to 6, which does not contain 10-camphorsulfonic acid.

8. consisting of only cation-modified silica particles, a non-aromatic bridged cyclic compound having an organic acid group or a salt thereof, an oxidizing agent and water, or The composition is composed only of cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof, an oxidizing agent, an antifungal agent, and water; The non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is represented by the following general formula 1: Polishing composition: 【Chemistry 2】 In the above general formula 1, Z １ is CR １ R １ ', C=O or O, Z ２ is CR ２ R ２ ', C=O or O, Z ３ is CR ３ R ３ ', C=O or O, Z ４ is CR ４ R ４ ', C=O or O, R １ , R １ ', R ２ , R ２ ', R ３ , R ３ ', R ４ , R ４ ', R ５ , R ６ , R ７ and R ８ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; The R １ , the R １ ', the R ２ , the R ２ ', the R ３ , the R ３ ', the R ４ , the R ４ ', the R ５ , the R ６ , the R ７ and the R ８ when at least one of the groups is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; The R １ , the R １ ', the R ２ , the R ２ ', the R ３ , the R ３ ', the R ４ , the R ４ ', the R ５ , the R ６ , the R ７ and the R ８ At least one of the groups contains an organic acid group or a salt thereof.

9. The concentration of the cation-modified silica particles is 1.8% by mass or more and 10% by mass or less, based on the total mass of the polishing composition; The concentration of the non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is 0.05 mass% or more and 0.5 mass% or less, based on the total mass of the polishing composition. The polishing composition according to claim 8.

10. The polishing composition according to claim 8 or 9, which is for polishing an object containing silicon oxide.

11. A polishing method, comprising polishing an object to be polished with the polishing composition according to any one of claims 1 to 10.

12. A method for producing a semiconductor substrate, comprising: polishing an object to be polished, which is a substrate material, by the polishing method according to claim 11.

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