Composition for polishing, method for producing the same, polishing method, and method for producing 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 Art

[0002] In recent years, with the multilayer wiring of the semiconductor substrate surface, when manufacturing a device, a so-called Chemical Mechanical Polishing (CMP) technique for polishing and planarizing the semiconductor substrate has been used. CMP is a method of planarizing the surface of an object to be polished (workpiece), such as a semiconductor substrate, using a polishing composition (slurry) containing abrasive grains such as silica, alumina, and ceria, a corrosion inhibitor, a surfactant, and the like. At this time, the object to be polished (workpiece) is made of silicon, polysilicon, silicon oxide (silicon dioxide), silicon nitride (silicon nitride), a film containing titanium nitride, titanium, tantalum nitride or tantalum, wiring made of a metal such as copper or tungsten, plugs, and the like.

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

Prior Art Documents

Patent Documents

[0004] Japanese Patent Document 1 Japanese Translation of PCT International Publication No. 2014-505358 Summary of the Invention Problems to be Solved by the Invention

[0005] However, in the chemical mechanical polishing composition of Patent Document 1, since the polishing suppression effect on silicon nitride is insufficient, there is a problem that the selectivity of other materials with respect to silicon nitride is also insufficient. Further, there is a problem that measures such as increasing the film thickness of the silicon nitride film in consideration of the loss are required.

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

[0007] One embodiment for solving the above problems of the present invention is shown below: A polishing composition comprising cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof, and water. Effects of the Invention

[0008] According to the present invention, a means capable of improving the polishing suppression effect on silicon nitride is provided. Embodiments for Carrying Out the Invention

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

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

[0011] The inventor speculates on the mechanism by which the above problems can be solved as follows.

[0012] The non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof adsorbs to the silicon nitride film (silicon nitride surface) having a positive charge by electrostatic attraction starting from the organic acid group or a salt thereof which is an anionic functional group. At this time, the non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof strongly protects the silicon nitride film from the abrasive grains by suppressing the collision between the abrasive grains and the silicon nitride film due to its bulky ring structure. As a result, the scraping action of the abrasive grains on the silicon nitride film is weakened. Further, since the cation-modified silica particles have a positive charge and the silicon nitride film also has a positive charge, an electrostatic repulsion acts between them, weakening the scraping action and scraping frequency of the abrasive grains on the silicon nitride film. And, when the cation-modified silica particles and the non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof are combined, the functions of both are synergistically improved, and the polishing suppression effect of the abrasive grains on the silicon nitride film is dramatically improved.

[0013] Note that the above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

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

[0015] (SiN Polishing Inhibitor) The polishing composition according to an embodiment of the present invention contains a compound that suppresses the polishing of silicon nitride (also referred to herein as "SiN polishing inhibitor"). The SiN polishing inhibitor is a non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof. As described above, the SiN polishing inhibitor acts to suppress the polishing of silicon nitride. Further, when polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride, the SiN polishing inhibitor acts to improve the selectivity of the other material with respect to silicon nitride due to the effect of suppressing the polishing of silicon nitride.

[0016] It should be noted that 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 crosslinked cyclic compound refers to a crosslinked compound excluding a structure in which one side is shared (i.e., a condensed ring compound) among compounds having a structure in which both ends of a linear structure portion of two or more substituents having one monocyclic structure are bonded and having no aromatic ring in the molecule. The non-aromatic crosslinked cyclic compound is not particularly limited, and examples thereof include camphor, adamantane, and derivatives in which a hydrocarbon group forming a ring in their molecular structures is substituted with another atom or functional group.

[0018] The group of the organic acid group or its salt is not particularly limited, but preferable examples include a carboxy group, a group of a salt of a carboxy group, a sulfo group, a group of a salt of a sulfo group, a phosphonic acid group, a group of a salt of a phosphonic acid group, a phosphoric acid group, and a group of a salt of a phosphoric acid group. That is, the non-aromatic crosslinked 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 group of a salt of a carboxy group, a sulfo group, a group of a salt of a sulfo group, a phosphonic acid group, a group of a salt of a phosphonic acid group, a phosphoric acid group, and a group of a salt of a phosphoric acid group. Among these, the non-aromatic crosslinked cyclic compound having an organic acid group or its salt group more preferably has a carboxy group, a group of a salt of a carboxy group, a sulfo group, or a group of a salt of a sulfo group, still more preferably has a carboxy group or a sulfo group, and particularly preferably has a sulfo group. According to these groups, the polishing suppression effect of silicon nitride is further improved. In addition, when polishing an object to be polished further containing another material (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other material with respect to silicon nitride is further improved.

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

[0020]

Chemical formula

[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 a group of an organic acid or its salt, 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 a group of an organic acid or its salt, At least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 contains a group of an organic acid or its salt.

[0022] In the general formula 1 above, it is preferable that at least one of Z1, Z2, Z3 and Z4 is C=O, more preferably at least one of Z1 and Z3 is C=O, still more preferably either one of Z1 and Z3 is C=O, and particularly preferably Z3 is C=O. At this time, the group that is not C=O among 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 more preferably CRR'.

[0023] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 of the general formula 1 above, 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 of the general formula 1 above, examples of the hydrocarbon group include an alkyl group, an alkenyl group or 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, and examples thereof include alkyl groups 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 group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 2-methylbutyl group and the like. Among these, linear alkyl groups having 1 to 5 carbon atoms are preferred, methyl group, ethyl group, n-propyl group and isopropyl group are more preferred, methyl group or ethyl group is even more preferred, and methyl group is particularly preferred.

[0026] The alkenyl group may be linear, branched or cyclic. The alkenyl group is not particularly limited, and examples thereof include 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 and the like.

[0027] The alkynyl group may be linear, branched or cyclic. The alkynyl group is not particularly limited, and examples thereof include 2-butynyl group, 3-pentynyl group, hexynyl group, heptynyl group, octynyl group, decynyl group and the like.

[0028] In R1, R1’, R2, R2’, R3, R3’, R4, R4’, R5, R6, R7 and R8 of the general formula 1 above, the alkoxy group is not particularly limited, and 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 of the general formula 1 above, 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 of the general formula 1 above, the organic acid group or its salt group is not particularly limited, but as described above, it is preferably 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, a carboxy group, a salt group of a carboxy group, a sulfo group, or a salt group of a sulfo group is more preferable, a carboxy group or a sulfo group is further preferable, and a sulfo group is particularly preferable.

[0031] In the 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 atom, hydrocarbon group (for example, alkyl group, alkenyl group, alkynyl group), alkoxy group, polyoxyalkylene group, organic acid group or its salt group as the substituent is the same as those described for these groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 in the general formula (1), respectively.

[0032] In the 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 (for example, substituted alkyl group, substituted alkenyl group, substituted alkynyl group), the substituents are preferably, respectively independently, a deuterium atom, a halogen atom, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or its salt group. Further, in the 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, respectively 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 its salt group.

[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 a group of an organic acid or its salt, or an alkyl group substituted with a group of an organic acid or its salt. Among these, it is more preferable that only one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is a group of an organic acid or its salt, or an alkyl group substituted with a group of an organic acid or its salt. At this time, as the group of an organic acid or its salt, or an alkyl group substituted with a group of an organic acid or its salt, 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 more preferable, a carboxy group or a methyl group substituted with a sulfo group is particularly preferable, and a methyl group substituted with a sulfo group is most preferable. According to these groups, the polishing suppression effect of silicon nitride is further improved. Further, when polishing an object to be polished containing, in addition to silicon nitride, another material (particularly titanium nitride), the selectivity of the other material with respect 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, still more preferably a substituted alkyl group, and particularly preferably an alkyl group substituted with a group of an organic acid or its salt. At this time, as the alkyl group substituted with a group of an organic acid or its salt, a methyl group substituted with a sulfo group or its salt group is preferable, and a methyl group substituted with a sulfo group is particularly preferable.

[0036] In the above general formula (1), R6 is preferably a hydrogen atom, or a group of an organic acid group or its salt, more preferably a hydrogen atom, or a carboxy group or its salt group, still 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 independently preferably a substituted or unsubstituted alkyl group, more preferably an unsubstituted alkyl group, and particularly preferably a methyl group.

[0038] Preferred specific examples of the SiN polishing inhibitor include (+)-10-camphorsulfonic acid, camphanic acid, ketopinonic acid and the like. Among these, (+)-10-camphorsulfonic acid or camphanic acid is preferred, and (+)-10-camphorsulfonic acid is more preferred.

[0039] The SiN polishing inhibitor can be used alone or in combination of two or more. Also, a synthetic product or a commercially available product may be used as the SiN polishing inhibitor.

[0040] The addition amount (concentration) of the SiN polishing inhibitor is not particularly limited, but it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, and particularly preferably 0.15% by mass or more with respect to the total mass of the polishing composition. When it is within this range, the polishing inhibitory effect on silicon nitride is further improved. In addition, when polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material to silicon nitride is further improved. The addition amount (concentration) of the SiN polishing inhibitor is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less with respect to the total mass of the polishing composition. When it is within this range, the effect of the SiN polishing inhibitor becomes higher. The reason for this is presumably that the electrical conductivity does not become excessively high, and the electric double layers of the abrasive grains and silicon nitride are not excessively compressed, so that the electrostatic repulsion between the abrasive grains and silicon nitride is better maintained. Also, when it is within this range, better dispersion stability of the slurry is ensured.

[0041] Alternatively, the addition amount (concentration) of the SiN polishing inhibitor is not particularly limited, but an amount may be appropriately selected so as to achieve the pH value of the desired polishing composition. At this time, it is preferable to add an amount so as to achieve the preferable pH value of the polishing composition described later. In addition, when adopting such an addition amount (concentration), although not particularly limited, it is particularly preferably adopted when not using the pH adjuster described later in combination.

[0042] (Abrasive grains) The polishing composition according to an 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 in the case of cation-modified silica particles, as described above, the polishing of silicon nitride is suppressed. In addition, when polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride, the abrasive grains act to improve the polishing rate of the other material and improve the selectivity ratio of the other material to silicon nitride.

[0043] The type of silica particles used as a raw material for the cation-modified silica particles is not particularly limited, and examples include fumed silica, colloidal silica, etc., but colloidal silica is preferred. Examples of the production method of colloidal silica include the sodium silicate method and the sol-gel method. Colloidal silica produced by any production method can be suitably used. 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 has a low content of metal impurities having the property of diffusing in a semiconductor and corrosive ions such as chloride ions. The production of colloidal silica by the sol-gel method can be carried out using a conventionally known technique. Specifically, a hydrolyzable silicon compound (for example, alkoxysilane or its derivative) is used as a raw material, and a hydrolysis / condensation reaction is carried out to obtain colloidal silica.

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

[0045] As the cation-modified silica particles, cation-modified colloidal silica is preferably used. And as the colloidal silica having a cationic group (cation-modified colloidal silica), colloidal silica with an amino group immobilized on the surface is preferably mentioned. As a method for producing such colloidal silica having a cationic group, as described in JP-A-2005-162533, a method of immobilizing a silane coupling agent having an amino group such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, aminobutyltriethoxysilane on the surface of silica particles can be mentioned. Thereby, colloidal silica with an amino group immobilized on the surface (amino group-modified colloidal silica) can be obtained. According to these cation-modified colloidal silicas, the polishing suppression effect of silicon nitride is further improved. Further, when polishing an object to be polished further containing another material (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material 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 columnar shapes such as triangular prisms and square prisms, cylindrical shapes, a cocoontype shape in which the central part of the cylinder bulges more than the end part, a donut shape in which the central part of the disk penetrates, plate shapes, a so-called cocoon shape having a constriction in the central part, a so-called aggregated spherical shape in which a plurality of particles are integrated, a so-called sugar ball shape having a plurality of protrusions on the surface, a rugby ball shape, and various other shapes, and there is no particular limitation. Among these, when polishing an object to be polished further containing silicon oxide as another material, a cocoon shape is preferable from the viewpoint of suppressing the silicon oxide polishing rate.

[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, still more preferably 10 nm or more, and particularly preferably 25 nm or more. When polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride within this range, the selectivity of the other material with respect to silicon nitride is further improved. Also, 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, still more preferably 50 nm or less. When within 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 perfect sphere. More specifically, the average primary particle diameter of the cation-modified silica particles can be calculated from the specific surface area of the cation-modified silica particles by the BET method measured using "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, still more preferably 30 nm or more, and particularly preferably 50 nm or more. When polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride within this range, the selectivity of the other material with respect to silicon nitride is further improved. Also, 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, still more preferably 150 nm or less, and particularly preferably 100 nm or less. When within 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, for example, by the dynamic light scattering method typified by the laser diffraction scattering method using a dynamic light scattering type particle diameter and particle size distribution apparatus UPA-UTI151 manufactured by Nikkiso Co., Ltd.

[0049] The degree of aggregation 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. When within this range, the polishing suppression effect of silicon nitride is further improved. Also, the degree of aggregation of the cation-modified silica particles is preferably 1 or more, and more preferably 1.2 or more. When within this range, when polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material to silicon nitride is further improved. The degree of aggregation of the cation-modified silica particles is obtained by dividing the value of the average secondary particle diameter of the cation-modified silica particles by the value of 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 more than 0 pieces / nm 2 and more preferably 0.2 pieces / nm 2 or more, even more preferably 1 piece / nm 2 or more, and particularly preferably 1.4 pieces / nm 2 or more. When within this range, the dispersibility of the abrasive grains is improved, and when polishing an object to be polished that further contains another material (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material to silicon nitride is further improved. Also, the silanol group density of the cation-modified silica particles is preferably 10 pieces / nm 2 or less, more preferably 6 pieces / nm 2 or less, even more preferably 4 pieces / nm 2 or less, and particularly preferably 2 pieces / nm 2 or less. The silanol group density of the cation-modified silica particles can be calculated by the following method after measuring or calculating each parameter by the following measurement method or calculation method.

[0051] In the following formula, C uses the total mass of the cation-modified silica particles, and S in the following formula 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 are taken 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 and dissolved. Next, 1N hydrochloric acid is added to adjust the pH of the slurry to about 3.0 to 3.5, and then pure water is added until the slurry reaches 150 ml. For this slurry, using an automatic titrator (manufactured by Hiranuma Sangyo Co., Ltd., COM-1700), at 25 °C, 0.1N sodium hydroxide is used to adjust the pH to 4.0, and further, the volume V [L] of the 0.1N sodium hydroxide solution required to raise the pH from 4.0 to 9.0 is measured by pH titration. The silanol group density can be calculated by the following formula.

[0052]

Number

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

[0054] Note that 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. When within this range, the polishing suppression effect of silicon nitride is further improved. Also, when polishing an object to be polished that further contains another material (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material with respect to silicon nitride is further improved. The reason for this is presumably that the positive charge of the cation-modified silica particles becomes stronger, the electrostatic repulsion between the cation-modified silica particles and the silicon nitride film becomes stronger, and the scraping action and scraping frequency of the abrasive grains on the silicon nitride film become weaker. From the same perspective, since 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, for example, it is more preferably 10 mV or more, even more preferably 20 mV or more, and particularly preferably 30 mV or more. Also, 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 Otsuka Electronics Co., Ltd.'s ELS-Z2, measuring it by the laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C, and analyzing the obtained data with Smoluchowski's equation.

[0056] The size (average primary particle diameter, average secondary particle diameter), degree of aggregation, silanol group density, and zeta potential in the polishing composition of the cation-modified silica particles can be appropriately controlled by, for example, the selection of the manufacturing method of the cation-modified silica particles. In particular, regarding the silanol group density, it is preferable to control it under conditions of heat treatment such as firing.

[0057] Note that the cation-modified silica particles can be used alone or in combination of two or more.

[0058] The addition amount (concentration) of the cation-modified silica particles 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 with respect to the total mass of the polishing composition. When within this range, when polishing an object to be polished that further contains other materials (particularly titanium nitride) in addition to silicon nitride, the selection ratio of other materials with respect to silicon nitride is further improved. Also, the addition amount (concentration) of the cation-modified silica particles 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 with respect to the total mass of the polishing composition. When within this range, the polishing suppression effect of silicon nitride is further improved.

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

[0060] However, in the polishing composition according to an embodiment of the present invention, it is preferable that the addition amount (concentration) of the other abrasive grains is as small as possible, and it is particularly preferable that the other abrasive grains are not substantially contained. In this specification, "not substantially containing other abrasive grains" means the case where the addition amount (concentration) of the other abrasive grains is less than 0.001% by mass with respect to the total mass of the polishing composition.

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

[0062]

Chem.

[0063] In the above general formula 2, X1 is CR 11 R 11 ’ or C=O, X2 is CR 12 R 12 ’ or C=O, X3 is CR 13 R 13 ’ or C=O, X4 is 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 ’ are each 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]

Chem.

[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 that binds to the ring-constituting nitrogen atom (N) of the above general formula 2, R 10 , R 11 , R 11 ’, R 12 , R 12 ’, R 13 , R 13 ’14 and R 14 ’ and R 15 When at least one of them 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 inhibit the polishing of silicon oxide, which is another material. Also, when polishing an object to be polished that further contains a material other than silicon oxide (particularly titanium nitride) in addition to silicon oxide, it acts to improve the selectivity of the material other than silicon oxide with respect to silicon oxide. The reason for this is not clear in detail, but it is speculated as follows. It has been confirmed that the silicon oxide polishing inhibitor adsorbs to the SiO2 sensor by QCM (quartz crystal microbalance). From this, the silicon oxide polishing inhibitor protects the silicon oxide film from abrasive grains by adsorbing to the silicon oxide film (silicon oxide surface) and suppressing the collision between the abrasive grains and the silicon oxide film. 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 contains a silicon oxide polishing inhibitor in addition to the cation-modified silica particles and the above SiN polishing inhibitor. The SiN polishing inhibitor acts on silicon nitride, and the silicon oxide polishing inhibitor acts on silicon oxide. Since their respective actions are exhibited well, according to the polishing composition, the effect of improving the selectivity of other materials with respect to silicon nitride and the effect of improving the selectivity of materials other than silicon oxide with respect to silicon oxide can be achieved simultaneously.

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

[0069] 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 ’ as well as R in the above general formula 3 15 In this case, the hydrocarbon group is not particularly limited, and examples thereof include an alkyl group, an alkenyl group, or an alkynyl group, etc. The alkyl group, alkenyl group, or alkynyl group is not particularly limited, and examples thereof include those similar to those described for these groups in R1, R1’, R2, R2’, R3, R3’, R4, R4’, R5, R6, R7, and R8 in the above general formula 1.

[0070] 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 this case, the oxyhydrocarbon group represents a group represented by “-OR””, and the R” represents a hydrocarbon group. The hydrocarbon group is the same as the description in R 10 , R 11 , R 11 ’, R 12 , R 12 ’, R 13 , R 13 ’, R 14 and R 14 ’ as well as R in the above general formula 3 15 is the same as the description.

[0071] In the above general formula 2, R 10 , R 11 , R 11 ’, R 12 , R 12 ’, R 13 , R13 ’, R 14 and R 14 ’, the polyoxyalkylene group is not particularly limited. For example, it may be the same as those exemplified in the description of the polyoxyalkylene groups in R1, R1’, R2, R2’, R3, R3’, R4, R4’, R5, R6, R7 and R8 in the general formula 1 above.

[0072] In the general formula 2 above, R 10 , R 11 , R 11 ’, R 12 , R 12 ’, R 13 , R 13 ’, R 14 and R 14 ’ is a substituted group, or in the general formula 3 above, when R 15 is a substituted group, the halogen atom as a substituent is not particularly limited. For example, F, Cl, Br, I, etc. may be mentioned. Also, the oxyhydrocarbon group and polyoxyalkylene group as substituents are the same as the descriptions of these groups in R 10 , R 11 , R 11 ’, R 12 , R 12 ’, R 13 , R 13 ’, R 14 and R 14 ’ respectively.

[0073] In the general formula 2 above, R 10 is preferably a group represented by the general formula 3. At this time, 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 general formula 2 above, R 11, R 11 ’, R 12 , R 12 ’, R 13 , R 13 ’, R 14 and R 14 ’ are more preferably all hydrogen atoms.

[0075] Specific examples of the silicon oxide polishing inhibitor are not particularly limited, and examples include 4-acetylmorpholine, 3-morpholinone, N-methyl-2-morpholinone, 4-vinyl-3-morpholinone, 4-acryloylmorpholine, 4-methacryloylmorpholine, and the like. Among these, 4-acetylmorpholine and 4-acryloylmorpholine are preferred. From the viewpoint of the effect of improving the selection ratio of other materials with respect to silicon nitride, 4-acetylmorpholine is more preferred, and from the viewpoint of the effect of improving the selection ratio of other materials with respect to silicon oxide, 4-acryloylmorpholine is more preferred.

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

[0077] The addition amount (concentration) of the silicon oxide polishing inhibitor is not particularly limited, but it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, and particularly preferably 0.25% by mass or more with respect to the total mass of the polishing composition. When it is within this range, the polishing inhibition effect of silicon oxide is further improved. In addition, when polishing an object to be polished that further contains a material other than silicon oxide (particularly titanium nitride) in addition to silicon oxide, the selection ratio of the material other than silicon oxide to silicon oxide is further improved. The addition amount (concentration) of the silicon oxide polishing inhibitor is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less with respect to the total mass of the polishing composition. When it is within this range, the effect of the silicon oxide polishing inhibitor becomes higher. The reason for this is presumably that the electrostatic repulsion between the abrasive grains and silicon oxide is better maintained because the electric conductivity does not become excessively high and the electric double layers of the abrasive grains and silicon oxide are not excessively compressed. Also, when it is within this range, better dispersion stability of the slurry is ensured.

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

[0079] The oxidizing agent is not particularly limited, and examples thereof include hydrogen peroxide, sodium peroxide, barium peroxide, ozone water, silver (II) salt, iron (III) salt, permanganic acid, chromic acid, dichromic acid, peroxydisulfuric acid, peroxymonophosphoric acid, peroxymonosulfuric acid, peroxymonoboric acid, performic acid, peracetic acid, perbenzoic acid, phthalic 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 viewpoints of handleability and safety. The oxidizing agent can be used alone or in combination of two or more.

[0080] The addition amount (concentration) of the oxidizing agent is not particularly limited, but it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more with respect to the total mass of the polishing composition. When within this range, the oxidation reaction of materials other than the silicon nitride film proceeds more sufficiently, and the selectivity of other materials with respect to silicon nitride is further improved. Also, the addition amount (concentration) of the oxidizing agent is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less with respect to the total mass of the polishing composition. When within this range, the influence 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 with respect to silicon nitride is further improved.

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

[0082] In the present specification, it is assumed that the above 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 having a pH adjusting function. For example, an acid or a basic compound can be used. Here, the basic compound refers to a compound having a function of dissolving in water and increasing the pH of water, and acts to increase the pH of the polishing composition when added to the polishing composition.

[0084] As the acid, either an inorganic acid or an organic acid may be used. The inorganic acid is not particularly limited, and 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, and 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, and examples thereof include hydroxides of alkali metals or Group 2 elements, ammonia, etc. Specific examples of the hydroxide of an alkali metal include potassium hydroxide (KOH), sodium hydroxide (NaOH), etc. Specific examples of the hydroxide of a Group 2 element include calcium hydroxide (Ca(OH)2), etc.

[0086] Among these, from the viewpoint of adjusting to the range of the optimum pH value described later, an inorganic acid or a basic compound is preferable. Further, as the inorganic acid, nitric acid is more preferable. As the basic compound, hydroxides of alkali metals or Group 2 elements are more preferable, and hydroxides of alkali metals are even more preferable. And, as the pH adjuster, nitric acid or potassium hydroxide is particularly preferable, and potassium hydroxide is extremely preferable.

[0087] Note that the pH adjuster can be used alone or in combination of two or more.

[0088] The addition amount (concentration) of the pH adjuster may be appropriately selected to be an amount that gives the desired pH value of the polishing composition, and it is preferable to add an amount that gives the preferable pH value of the polishing composition described later.

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

[0090] (Electrical Conductivity Adjuster) The polishing composition according to an embodiment of the present invention may further contain an electric conductivity adjuster. The electric conductivity adjuster acts to improve the effect of suppressing the polishing rate of silicon nitride or to improve the dispersion stability of the polishing composition by adjusting the electric conductivity of the polishing composition to an appropriate range.

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

[0092] Examples of the salt compound include salts of acids, salts of basic compounds, etc. The salt of an acid may be an organic acid salt or an inorganic acid salt. The inorganic acid salt is not particularly limited, and examples include 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 the salt of a basic compound are not particularly limited, and include potassium chloride, sodium chloride, potassium bromide, potassium iodide, ammonium citrate, etc. The salt compound may be used alone or in combination of two or more.

[0093] The addition amount (concentration) of the electric conductivity adjuster may be appropriately selected so as to achieve the desired electric conductivity of the polishing composition, and it is preferable to add an amount such that the value of the preferable electric conductivity of the polishing composition described later is obtained.

[0094] (Electric conductivity) The electrical conductivity (EC) of the polishing composition according to an embodiment of the present invention is not particularly limited. However, the lower limit value 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. When within this range, the polishing suppression effect of silicon nitride is further enhanced. This is presumably because at low electrical conductivity, the electrostatic repulsive force acting between the abrasive grains and silicon nitride is maintained at a higher level. Also, the upper limit value of the electrical conductivity is preferably less than 10 mS / cm. When within this range, the dispersion stability of the polishing composition is further improved. Furthermore, the upper limit value of the electrical conductivity is more preferably 2 mS / cm or less, and even more preferably 1 mS / cm or less. When within this range, the polishing rate suppression effect of the silicon nitride film is further improved. This is presumably because when the electrical conductivity rises excessively, the electrostatic repulsion between the abrasive grains and the silicon nitride film does not weaken. From these viewpoints, an example of the preferable range of the electrical conductivity is a range of 30 μS / cm or more and 2 mS / cm or less. The electrical conductivity of the polishing composition can be evaluated using a desktop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71).

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

[0096] (Dispersion medium) The polishing composition according to an embodiment of the present invention further includes 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 water content in the dispersion medium is not particularly limited, but it is preferably 50% by mass or more, more preferably 90% by mass or more, and even more preferably only water, based on the total mass of the dispersion medium. From the viewpoint of preventing inhibition of the contamination of the object to be cleaned and the action of other components, water containing as few impurities as possible is preferred, and water having a total transition metal ion content of 100 ppb or less is preferred. Here, the purity of water can be increased by operations such as removal of impurity ions using an ion exchange resin, removal of foreign substances by a filter, and distillation. Specifically, it is preferable to use deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc. as the water.

[0098] In addition, when the dispersion medium can improve the dispersibility or solubility of each component, it may be a mixed solvent of water and an organic solvent. The organic solvent is not particularly limited, and known organic solvents can be used. When using a mixed solvent of water and an organic solvent, it is preferably an organic solvent miscible with water. When using an organic solvent, after mixing water and the organic solvent to prepare a mixed solvent, each component may be added to and mixed with the mixed solvent, or after dispersing or dissolving each component in the organic solvent, it may be mixed with water. Note that the organic solvent can be used alone or in combination of two or more.

[0099] (Other components) The polishing composition according to an embodiment of the present invention may further contain other components as long as the effects of the present invention are not inhibited. The other components are not particularly limited, but can be appropriately selected from various components used in known polishing compositions, such as wetting agents, surfactants, chelating agents, preservatives, fungicides, dissolved gases, reducing agents, and the like.

[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] The silicon-containing materials other than silicon nitride are not particularly limited. For example, materials having a silicon-oxygen bond (such as silicon oxide, etc.), materials having a silicon-silicon bond (such as polysilicon, etc.), materials having a silicon-nitrogen bond other than silicon nitride, and the like can be mentioned. Here, the materials having a silicon-oxygen bond are not particularly limited. For example, silicon oxide, BD (Black Diamond: SiOCH), FSG (Fluorinated Silicate Glass), HSQ (Hydrogen Silsesquioxane), CYCLOTENE, SiLK, MSQ (Methyl silsesquioxane), and the like can be mentioned. Further, the polishing target having a silicon-silicon bond is not particularly limited. For example, 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 can be mentioned. And, the materials having a silicon-nitrogen bond other than silicon nitride are not particularly limited. For example, silicon carbonitride (SiCN), etc. can be mentioned. Among these, from the viewpoint of being polished at a higher polishing rate by the polishing target according to an embodiment of the present invention and further improving the selectivity of other materials with respect to silicon nitride, a material having a silicon-silicon bond is preferable, and polysilicon is more preferable. Also, among these, when the polishing composition further contains the above-mentioned silicon oxide polishing inhibitor, a material having a silicon-oxygen bond is preferable, and silicon oxide is more preferable. This is because both the effect of improving the selectivity of other materials with respect to silicon nitride and the effect of improving the selectivity of other materials other than silicon oxide with respect to silicon oxide are achieved. The film containing silicon oxide is not particularly limited. For example, a TEOS (Tetraethyl Orthosilicate) type silicon oxide (also referred to as "TEOS-SiO2" in this specification) film produced using tetraethyl orthosilicate as a precursor, an HDP (High Density Plasma) film, an USG (Undoped Silicate Glass) film, a PSG (Phosphorus Silicate Glass) film, a BPSG (Boron-Phospho Silicate Glass) film, an RTO (Rapid Thermal Oxidation) film, and the like can be mentioned.As for the silicon oxide, TEOS-SiO2 is particularly preferred. Therefore, as the object to be polished, in addition to silicon nitride, it is particularly preferred that the object to be polished further contains silicon oxide (preferably TEOS-SiO2).

[0103] Also, the metal is not particularly limited, and examples thereof include copper, aluminum, hafnium, cobalt, nickel, titanium, tungsten, and alloys thereof. The metal oxide is not particularly limited, and examples thereof include alumina. The metal nitride is not particularly limited, and 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 object to be polished according to an embodiment of the present invention and further improving the selectivity of other materials with respect to silicon nitride, as other materials, it is preferable that they are metal nitrides, and more preferably titanium nitride. Therefore, as the object to be polished, in addition to silicon nitride, it is particularly preferred that the object to be polished further contains titanium nitride.

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

[0105] (Selectivity of other materials with respect to silicon nitride) In the polishing method using the polishing composition according to an embodiment of the present invention, when polishing an object to be polished that further contains another material in addition to silicon nitride, the selection ratio of the other material to silicon nitride is not particularly limited, but a higher ratio is preferred. For example, when the other material is titanium nitride, the selection ratio of titanium nitride to silicon nitride is not particularly limited, but is preferably 40 or more, more preferably 50 or more, further 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. Further, for example, when the other material is silicon oxide, the selection ratio of titanium nitride to silicon oxide is not particularly limited, but is preferably more than 15, more preferably 20 or more, and further preferably 25 or more. Note that the selection ratio of the other material to silicon nitride can be obtained by dividing the polishing rate of the other material by the polishing rate of silicon nitride.

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

[0107] Further, in the method for producing a polishing composition according to an embodiment of the present invention, the silicon oxide polishing inhibitor described above and other components may be further mixed. Thus, as a preferred embodiment of the production method according to the present invention, for example, those including further mixing the compound represented by the general formula 2 above can be mentioned.

[0108] The mixing method when mixing each component is not particularly limited, and known methods can be appropriately used. Also, the mixing temperature is not particularly limited, but generally 10 to 40°C is preferred, and heating may be performed to increase the dissolution rate. Also, the mixing time is not particularly limited.

[0109] In addition, with regard to the method for producing the polishing composition, the preferred embodiments (type, characteristics, structure, addition amount, etc.) of each component are the same as the description of each component of the above polishing composition. Also, various characteristics including the preferred characteristics of the produced polishing composition are the same as the description of the above polishing composition.

[0110] <Polishing method> Another aspect of the present invention relates to a polishing method in which a polishing object is polished using the above polishing composition or by manufacturing a polishing composition by the above manufacturing method and using the manufactured polishing composition.

[0111] The polishing object to be polished in the polishing method is the same as the description of the above polishing composition.

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

[0113] The polishing apparatus is equipped with a holder for holding the polishing object and a motor etc. whose rotation speed can be changed, and a general polishing apparatus having a polishing platen to which a polishing pad (polishing cloth) can be attached can be used. As the polishing apparatus, either a single-sided polishing apparatus or a double-sided polishing apparatus may be used. As the polishing pad, general non-woven fabrics, polyurethanes, porous fluororesins, etc. can be used without particular limitation. It is preferable that the polishing pad is grooved so that the polishing liquid can accumulate.

[0114] The polishing conditions are not particularly limited, and appropriate conditions can be set as appropriate according to the characteristics of the polishing composition and the object to be polished. Regarding the polishing load (polishing pressure, processing pressure), there is no particular limitation, 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. Within this range, while obtaining a high polishing rate, it is possible to further suppress the breakage of the substrate due to the load and the occurrence of defects such as scratches on the surface. The platen rotation speed and the carrier rotation speed are not particularly limited, but generally, they are 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, respectively. The method of supplying the polishing composition is also not particularly limited, and a method of continuously supplying it with a pump or the like (flow-through) may be adopted. The supply amount of the polishing composition (flow rate of the polishing composition) may be any 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 may be appropriately set so as to obtain the desired polishing result and is not particularly limited, but generally, it is preferably 5 seconds or more and 180 seconds or less. Also, the polishing is preferably performed using in-situ dressing. Here, in-situ dressing refers to a technique of performing dressing (truing) of the pad while polishing. According to in-situ dressing, the uniformity of the polishing rate with respect to the polishing time can be further improved, and the controllability of the polishing can be further improved. As the in-situ dressing member, it is preferable to use a conditioner such as a diamond dresser.

[0115] After polishing, the polished object to be polished may be dried by removing the water droplets adhering to the surface with a spin dryer, air blow, or the like after washing with water.

[0116] In the polishing method according to an embodiment of the present invention, when polishing an object to be polished that further contains another material in addition to silicon nitride, the selection ratio of the other material to silicon nitride is not particularly limited, but a higher ratio is preferable. The preferable range of the selection ratio of titanium nitride to silicon nitride is the same as the description of the above polishing composition. Further, the preferable range of the selection ratio of titanium nitride to silicon dioxide is the same as the description of the above polishing composition.

[0117] <Method for manufacturing a semiconductor substrate> Another embodiment of the present invention relates to a method for manufacturing a semiconductor substrate, which includes a step of polishing a substrate material (polishing step) by the above polishing method, where the object to be polished is the substrate material. That is, this embodiment involves polishing a substrate material used for forming a semiconductor substrate that contains titanium nitride, using the above polishing composition or manufacturing the polishing composition by the above manufacturing method and then using the manufactured polishing composition for polishing.

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

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

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

Examples

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

[0122] <Preparation 1 of Polishing Composition> (Polishing Composition 1) To pure water as a dispersion medium, colloidal silica A (average primary particle diameter 35 nm; average secondary particle diameter 70 nm; silanol group density 1.5 per nm 2 ; degree of aggregation 2.0), which is colloidal silica having an amino group immobilized on the surface as abrasive grains, (+)-10-camphorsulfonic acid as a SiN polishing inhibitor, hydrogen peroxide as an oxidizing agent, and nitric acid as a pH adjuster were added to prepare Polishing Composition 1.

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

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

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

[0126] (Polishing compositions 2 to 12) Except that the types and addition amounts (concentrations) of each component and the pH of the polishing composition were changed as shown in Table 1 below, the polishing compositions were prepared in the same manner as the preparation of polishing composition 1. Here, in the preparation of each polishing composition, the addition amount of the pH adjuster was the amount such that the pH of the polishing composition to be prepared became the value in Table 1 below. Note that the pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as polishing composition 1, respectively.

[0127] (Polishing compositions 13 and 14) Except for changing the type and addition amount (concentration) of each component and the pH of the polishing composition as shown in Table 1 below, each polishing composition was prepared in the same manner as the preparation of polishing composition 1. Here, as the abrasive grains, colloidal silica B in which a sulfo group is immobilized on the surface (average primary particle diameter: 13.8 nm; average secondary particle diameter: 33 nm; silanol group density: 2.2 pieces / nm 2 ; degree of aggregation: 2.39) was used. The pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as those of polishing composition 1, respectively.

[0128] <Polishing method 1> (Polishing apparatus and polishing conditions) Using each polishing composition prepared above, the surface of the object to be polished was polished under the following apparatus and conditions. As the objects to be polished, a TiN blanket wafer which is a TiN film (titanium nitride film) with a thickness of 2500 Å formed on the substrate surface and a SiN blanket wafer which is a SiN film (silicon nitride film) with a thickness of 2000 Å formed on the substrate surface were used: 〔Polishing apparatus and polishing conditions〕 Polishing apparatus: EJ-380IN-CH (manufactured by Nippon Engis Co., Ltd.) Polishing pad: IC1000 (manufactured by Nitto Haas Co., Ltd. (currently: Nitto DuPont Co., Ltd.)) Polishing pressure (processing pressure): 3.43 psi (note that 1 psi = 6894.76 Pa) Rotation speed of the polishing platen: 60 rpm (note that 60 rpm = 1 s -1 is) Supply amount of the polishing composition: 100 mL / min Polishing time: 60 sec Conditioner (In-situ dressing member): Diamond dresser (SDT-100, manufactured by Noritake Company Limited).

[0129] <Evaluation 1> (Measurement of polishing rate) Each of the above-mentioned objects to be polished was polished using each polishing composition, and the polishing rate (Å / min) of the TiN film and the polishing rate (Å / min) of the SiN film were measured. The polishing rate of the TiN film was determined by dividing the difference in thickness (Å) of the TiN blanket wafer before and after polishing measured using a sheet resistance measuring instrument based on the principle of the DC four-probe method by the polishing time (min). The polishing rate of the SiN film was determined 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 (manufactured by Filmmetrics Co., Ltd.: model number Filmetrics F50) by the polishing time (min). Note that 1 Å = 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 above, it was confirmed that the polishing compositions 1 to 3, 11, and 12 according to the examples containing 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 ratio 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 1 to 3, 11, and 12 according to the examples are particularly suitable for polishing objects to be polished further containing titanium nitride in addition to silicon nitride.

[0133] On the one hand, the polishing compositions 4 to 6, 8 according to the comparative examples not containing the SiN polishing inhibitor, the polishing compositions 7, 9, 10 according to the comparative examples containing a comparative compound having a structure different from that of the SiN polishing inhibitor of the present invention, the polishing composition 14 according to the comparative example containing anionic modified silica particles instead of cationic modified silica particles, and the polishing composition 13 according to the comparative example containing anionic modified silica particles instead of cationic modified silica particles and not containing the SiN polishing inhibitor were confirmed to be inferior in the polishing inhibiting effect of the SiN film compared with the polishing compositions 1 to 3, 11 and 12 according to the examples. As a result, it was also confirmed that the selectivity of the TiN film with respect to the SiN film was lowered.

[0134] <Preparation of Polishing Composition 2> (Polishing Composition 15) To pure water as a dispersion medium, colloidal silica C (average primary particle diameter: 23 nm; average secondary particle diameter: 50 nm; silanol group density: 3.6 pieces / nm 2 ; degree of aggregation: 2.2, cocoon shape), (+)-10-camphorsulfonic acid as the SiN polishing inhibitor, 4-acetylmorpholine as the silicon oxide polishing inhibitor, and hydrogen peroxide as the oxidizing agent were added to prepare the polishing composition 15.

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

[0136] Also, 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 benchtop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71). The electrical conductivity (EC) of the 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 subjected to ELS-Z2 manufactured by Otsuka Electronics Co., Ltd. Using a flow cell at a measurement temperature of 25°C, measurement was performed by the laser Doppler method (electrophoretic light scattering measurement method). Then, by analyzing the obtained data with Smoluchowski's equation, the zeta potential (mV) of the abrasive grains in the polishing composition was calculated. The zeta potential of the abrasive grains in the polishing composition 15 was 21 mV.

[0138] (Polishing compositions 16 to 18) Each polishing composition was prepared in the same manner as the preparation of the polishing composition 15, except that the type and addition 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 addition amount of (+)-10-camphorsulfonic acid as the SiN polishing inhibitor was an amount such that the pH of the prepared polishing composition became the value in Table 3 below. Note that the pH, electrical conductivity, and zeta potential of the abrasive grains were also measured in the same manner as the polishing composition 15, respectively.

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

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

[0141] <Evaluation 2> (Measurement of Polishing Rate) Each of the above objects to be polished was polished using each of the polishing compositions, and the polishing rate (Å / min) of the TiN film, the polishing rate (Å / min) of the SiN film, and the polishing rate (Å / min) of the TEOS-SiO2 film were measured. The polishing rate of the TiN film was obtained by dividing the difference in the thickness (Å) of the TiN blanket wafer before and after polishing, measured using a sheet resistance measuring instrument based on the direct current four-probe method, by the polishing time (min). The polishing rate of the SiN film was obtained by dividing the difference in the thickness (Å) of the SiN blanket wafer before and after polishing, measured using an optical interference film thickness measuring device (manufactured by Filmmetrics Co., Ltd.: model number Filmetrics F50), by the polishing time (min). The polishing rate of the TEOS-SiO2 film was obtained by dividing the difference in the thickness (Å) of the TEOS blanket wafer before and after polishing, measured using an optical interference film thickness measuring device (manufactured by KLA-Tencor Corporation: 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 the polishing composition) Regarding the polishing compositions 15 to 19 prepared above, immediately after preparation (10 minutes after adjustment), the presence or absence of abrasive precipitation was visually confirmed. Further, it was left standing in a constant temperature storage at 25°C, and after 3 months, the presence or absence of abrasive precipitation was visually confirmed. The evaluation results are shown in Table 4 below.

[0143]

Table 3

[0144]

Table 4

[0145] From the results of Table 3 and Table 4 above, it was confirmed that the polishing compositions 15 to 18 according to the examples containing cation-modified silica particles and the SiN polishing inhibitor of the present invention can significantly suppress the polishing of the SiN film. Further, it was also confirmed that the selectivity of the TiN film with respect to the SiN film can be significantly increased while maintaining the 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 a polishing object further containing titanium nitride in addition to silicon nitride. Also, it was confirmed that these polishing compositions have excellent stability.

[0146] Furthermore, it was confirmed that the polishing compositions 15 to 17 according to the examples containing 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 and can also significantly suppress the polishing of the silicon oxide film. Further, it was also confirmed that the selectivity of the TiN film with respect to the silicon oxide film can be significantly increased in addition to the selectivity of the TiN film with respect to the SiN film while maintaining the 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 a polishing object further containing titanium nitride in addition to silicon oxide. Also, it can be seen that the polishing compositions 15 to 17 according to the examples are particularly suitable for polishing a polishing object further containing 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 not containing the SiN polishing inhibitor is inferior in the polishing suppression effect of the SiN film compared to the polishing compositions 15 to 18 according to the examples. As a result, it was confirmed that the selectivity of the TiN film with respect to the SiN film also decreases.

Claims

1. A polishing composition for an object to be polished containing silicon nitride, comprising cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt group thereof, and water, wherein the non-aromatic crosslinked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1, 【Chemical 1】 in the above general formula 1, Z １ is CR １ R １ ’, C=O or O, and Z ２ is CR ２ R ２ ’, C=O or O, and Z ３ is CR ３ R ３ ’, C=O or O, and Z ４ is CR ４ R ４ ', C=O or O, and R １ 、 R １ ’, R ２ 、 R ２ ’, R ３ 、 R ３ ’, R ４ 、 R ４ ’, R ５ 、 R ６ 、 R ７ および 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 a group of an organic acid or a salt thereof, said R １ 、said R １ ’, said R ２ 、said R ２ ’, said R ３ 、said R ３ ’, said R ４ 、said R ４ ’, said R ５ 、said R ６ 、said R ７ and said R ８ when at least one of them 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 a group of an organic acid or its salt, said R １ 、said R １ ’, said R ２ 、said R ２ ’, said R ３ 、said R ３ ’, said R ４ 、said R ４ ’, said R ５ 、said R ６ 、said R ７ and said R ８ at least one of them contains an organic acid group or a salt group thereof, the concentration of the cation-modified silica particles is 1.8% by mass or more and 5% by mass or less based on the total mass of the polishing composition, the pH is 1.5 or more and 4 or less, A polishing composition for an object to be polished containing silicon nitride.

2. In the general formula (1), the Z １ , the Z ２ , the Z ３ and the Z ４ wherein at least one of them is C=O, the polishing composition according to claim 1.

3. In the general formula (1), 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 wherein at least one of them is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof, the polishing composition according to claim 1 or 2.

4. 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. The polishing composition according to any one of claims 1 to 3.

5. The polishing composition according to any one of claims 1 to 4, wherein the zeta potential of the cation-modified silica particles is a positive value.

6. The polishing composition according to any one of claims 1 to 5, further comprising a compound represented by the following general formula 2: 【Chemical 2】 in the above general formula 2, X １ is CR １１ R １１ ’ or C=O, and X ２ is CR １２ R １２ ’ or C=O, and X ３ is CR １３ R １３ ’ or C=O, and X ４ is CR １４ R １４ ’ or C=O, and R １０ 、 R １１ 、 R １１ ’, R １２ 、 R １２ ’, R １３ 、 R １３ ’, R １４ および R １４ ’ are each 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, 【Chemical Formula 3】 In the general formula 3 above, R １５ is a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted hydrocarbon group, * is a bond that binds to the ring-constituting nitrogen atom (N) of the above general formula 2, said R １０ 、said R １１ 、said R １１ ’, said R １２ 、said R １２ ’, said R １３ 、said R １３ ’, said R １４ 、said R １４ ’ and said R １５ When at least one of them is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group.

7. The polishing composition according to any one of claims 1 to 6, further comprising an oxidizing agent.

8. The polishing composition according to any one of claims 1 to 7, having an electric conductivity of 30 μS / cm or more and 2 mS / cm or less.

9. The polishing composition according to any one of claims 1 to 8, for an object to be polished further containing titanium nitride.

10. The polishing composition according to any one of claims 1 to 9, for an object to be polished further containing silicon oxide.

11. A method for producing a polishing composition for an object to be polished containing silicon nitride, comprising mixing cation-modified silica particles, a non-aromatic crosslinked cyclic compound having an organic acid group or a salt group thereof, and water, wherein the non-aromatic crosslinked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1, 【Chemical 4】 in the above general formula 1, Z １ is CR １ R １ ', C=O or O, and Z ２ is CR ２ R ２ ’, C=O or O, and Z ３ is CR ３ R ３ ', C=O or O, and Z ４ is CR ４ R ４ ’, C=O or O, and R １ 、 R １ ’, R ２ 、 R ２ ’, R ３ 、 R ３ ’, R ４ 、 R ４ ’, R ５ 、 R ６ 、 R ７ および 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 a group of an organic acid or a salt thereof, said R １ 、said R １ ’, said R ２ 、said R ２ ’, said R ３ 、said R ３ ’, said R ４ 、said R ４ ’, said R ５ 、said R ６ 、said R ７ and said R ８ is a group in which at least one of them 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 a group of an organic acid or a salt thereof, Said R １ 、said R １ ’, said R ２ 、said R ２ ’, said R ３ 、said R ３ ’, said R ４ 、said R ４ ’, said R ５ 、said R ６ 、said R ７ and said R ８ at least one of which contains an organic acid group or a group of its salt, the concentration of the cation-modified silica particles is 1.8% by mass or more and 5% by mass or less based on the total mass of the polishing composition, the pH is 1.5 or more and 4 or less, A method for producing a polishing composition for an object to be polished containing silicon nitride.

12. The method for producing a polishing composition according to claim 11, further comprising mixing a compound represented by the following general formula 2: 【Chemical Formula 5】 in the above general formula 2, X １ is CR １１ R １１ ’ or C=O, and X ２ is CR １２ R １２ ’ or C=O, and X ３ is CR １３ R １３ ’ or C=O, and X ４ is CR １４ R １４ ’ or C=O, and R １０ 、R １１ 、R １１ ’, R １２ 、R １２ ’, R １３ 、R １３ ’, R １４ およびR １４ ’ are each 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, [Chemical Formula 6] In the general formula 3 above, R １５ is a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted hydrocarbon group, * represents a bond that binds to the ring-constituting nitrogen atom (N) of the general formula (2), the foregoing R １０ 、the foregoing R １１ 、the foregoing R １１ ’, the foregoing R １２ 、the foregoing R １２ ’, the foregoing R １３ 、the foregoing R １３ ’, the foregoing R １４ 、the foregoing R １４ ’ and the foregoing R １５ is a group in which at least one of them is substituted, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group. **Claim 13** Using the polishing composition according to any one of Claims 1 to 10, or manufacturing a polishing composition by the manufacturing method according to Claim 11 or 12, and using the manufactured polishing composition, A polishing method for polishing an object to be polished. **Claim 14** A method for manufacturing a semiconductor substrate, wherein the object to be polished is a substrate material, and the substrate material is polished by the polishing method according to Claim 13.

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