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

Abstract

The present invention provides a means to improve the polishing inhibition effect of silicon nitride. The present invention relates to a polishing composition comprising cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water.

Description

Technology Field

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

[0002] In recent years, along with the multilayer wiring on the surface of semiconductor substrates, so-called Chemical Mechanical Polishing (CMP) technology is being used to polish and flatten the semiconductor substrate when manufacturing devices. CMP is a method of flattening the surface of a polishing target (workpiece), such as a semiconductor substrate, by using a polishing composition (slurry) containing abrasive particles such as silica, alumina, or ceria, anti-corrosion agents, surfactants, etc. At this time, the polishing target (workpiece) is silicon, polysilicon, silicon oxide, silicon nitride, films containing titanium nitride, titanium, tantalum nitride, or tantalum, wiring containing metals such as copper or tungsten, plugs, etc.

[0003] In CMP technology, silicon nitride is used as a stopper film (etching mask), and at this time, it is preferable that the ratio of the polishing speed of a material other than silicon nitride (hereinafter also referred to simply as "other material" in this specification) to the polishing speed of silicon nitride (selectivity ratio of the other material to silicon nitride) be larger. Regarding the polishing of a polishing target using silicon nitride as a stopper film, Japanese Patent Publication No. 2014-505358 (corresponding to International Publication No. 2012 / 083115) discloses a chemical mechanical polishing composition comprising silica, aminophosphonic acid, a polysaccharide, a tetraalkylammonium salt, a bicarbonate, a compound including an azole ring, potassium hydroxide as an optional component, and water, with a pH of 7 to 11. In addition, Japanese Patent Publication No. 2014-505358 (corresponding to International Publication No. 2012 / 083115) discloses that when polishing is performed at a high polishing pressure using the said chemical mechanical polishing composition, the selectivity ratio of polysilicon to silicon nitride, which is a stopper film, and the selectivity ratio of polysilicon to silicon oxide, which is an insulating film, are improved.

[0004] However, in the chemical mechanical polishing composition of Japanese Patent Publication No. 2014-505358 (corresponding to International Publication No. 2012 / 083115), there is a problem in that the polishing inhibition effect of silicon nitride is insufficient, resulting in an insufficient selectivity ratio of other materials to silicon nitride. Furthermore, there is a problem in that countermeasures, such as increasing the film thickness of the silicon nitride film to account for the loss, become necessary.

[0005] Therefore, the present invention aims to provide a means to improve the polishing inhibition effect of silicon nitride.

[0006] One embodiment for solving the above problem of the present invention is shown below:

[0007] A polishing composition comprising cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water. Specific details for implementing the invention

[0008] Embodiments of the present invention are described below. Furthermore, the present invention is not limited to the following embodiments. Also, in this specification, "X to Y" indicating a range means "X or greater and Y or less." Also, unless otherwise noted, operations and measurements of physical properties, etc. are performed under conditions of room temperature (range of 20°C or higher and 25°C or lower) and relative humidity of 40% RH or higher and 50% RH or lower.

[0009] Abrasive composition

[0010] One embodiment of the present invention relates to a polishing composition comprising cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water. According to one embodiment of the present invention, means are provided to improve the polishing inhibition effect of silicon nitride.

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

[0012] A non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is adsorbed onto a silicon nitride film (silicon nitride surface) having a positive charge through electrostatic attraction, based on the anionic functional group, the organic acid group or its salt group thereof. At this time, the non-aromatic cross-linked cyclic compound having an organic acid group or its salt group strongly protects the silicon nitride film from the abrasive particles by suppressing collisions between the abrasive particles and the silicon nitride film through its bulky ring structure. As a result, the scraping action of the abrasive particles on the silicon nitride film is weakened. In addition, since the cationic modified silica particles have a positive charge and the silicon nitride film also has a positive charge, electrostatic repulsion acts between them, and the scraping action and scraping frequency of the abrasive particles on the silicon nitride film are weakened. In addition, by combining cationic modified silica particles with a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, the functions of both are synergistically enhanced, and the polishing inhibition effect of the silicon nitride film of the abrasive particles is dramatically improved.

[0013] Furthermore, the above mechanism is based on conjecture, and its accuracy does not affect the technical scope of the present invention.

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

[0015] (SiN polishing inhibitor)

[0016] A polishing composition according to one embodiment of the present invention comprises a compound that inhibits the polishing of silicon nitride (also referred to herein as a "SiN polishing inhibitor"). The SiN polishing inhibitor is a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof. As described above, the SiN polishing inhibitor acts to inhibit the polishing of silicon nitride. Furthermore, when polishing a workpiece that includes, in addition to silicon nitride, another material (particularly titanium nitride), the effect of inhibiting the polishing of silicon nitride acts to improve the selectivity ratio of the other material to silicon nitride.

[0017] In addition, the adsorption of the SiN polishing inhibitor onto the silicon nitride film can be confirmed by TOF-SIMS analysis.

[0018] In this specification, a non-aromatic cross-linked cyclic compound refers to a cross-linked compound that does not have an aromatic ring within the molecule and has a structure in which both ends of a straight-chain portion of two or more substituents of a single ring structure are joined, excluding a structure in which one side is shared (i.e., a condensed ring compound). Non-aromatic cross-linked cyclic compounds are not particularly limited, but examples include camphor, adamantane, and derivatives formed by substituting a hydrocarbon group forming a ring in the molecular structure of these compounds with another atom or functional group.

[0019] The organic acid group or its salt group is not particularly limited, but preferred examples include a carboxyl group, a salt group of a carboxyl group, a sulfonate group, a salt group of a sulfonate group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group. That is, a non-aromatic cross-linked cyclic compound having an organic acid group or its salt group preferably has at least one selected from the group consisting of a carboxyl group, a salt group of a carboxyl group, a sulfonate group, a salt group of a sulfonate group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group. Furthermore, among these, a non-aromatic cross-linked cyclic compound having an organic acid group or its salt group is more preferably having a carboxyl group, a salt group of a carboxyl group, a sulfonate group, or a salt group of a sulfonate group, is even more preferably having a carboxyl group or a sulfonate group, and is particularly preferably having a sulfonate group. According to these groups, the polishing inhibition effect of silicon nitride is further enhanced. In addition, when polishing a workpiece that includes other materials (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved.

[0020] As a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, it is not particularly limited, but it is preferable to be a compound represented by the following general formula 1 in terms of further enhancing the polishing inhibition effect of silicon nitride and having a high polishing rate for other materials.

[0021]

[0022] In the above general formula 1,

[0023] Z1 is CR1R1', C=O or O, and

[0024] Z2 is CR2R2', C=O or O, and

[0025] Z3 is CR3R3', C=O or O, and

[0026] Z4 is CR4R4', C=O or O, and

[0027] R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group (e.g., a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted alkynyl group), a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and

[0028] In the case where at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted hydrocarbon group (e.g., an unsubstituted alkyl group, an unsubstituted alkenyl group, or an unsubstituted alkynyl group), an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and

[0029] At least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 includes an organic acid group or a salt group thereof.

[0030] In the above general formula 1, it is preferable that at least one of Z1, Z2, Z3, and Z4 has C=O, more preferable that at least one of Z1 and Z3 has C=O, even more preferable that either Z1 or Z3 has C=O, and particularly preferable that Z3 has C=O. At this time, the group of Z1, Z2, Z3, and Z4 that does not have C=O is preferably CRR' (hereinafter, R corresponds to R1 to R4 respectively for Z1 to Z4, and R' corresponds to R1' to R4' respectively for Z1 to Z4) or O, and more preferable that it is CRR'.

[0031] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 of the above general formula 1, the halogen atoms are not particularly limited, but examples include F, Cl, Br and I, etc.

[0032] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 of the above General Formula 1, the hydrocarbon groups may be, for example, alkyl groups, alkenyl groups, or alkynyl groups. Among these, alkyl groups are preferred.

[0033] The alkyl group may be straight-chain, branched, or cyclic. As for the alkyl group, there are no particular limitations, but examples include alkyl groups having 1 to 12 carbon atoms. Among these, straight-chain or branched alkyl groups having 1 to 5 carbon atoms are preferred, and specific examples include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, neopentyl groups, 2-methylbutyl groups, etc. Among these, straight-chain alkyl groups having 1 to 5 carbon atoms are preferred, methyl groups, ethyl groups, n-propyl groups, and isopropyl groups are more preferred, methyl groups or ethyl groups are even more preferred, and methyl groups are particularly preferred.

[0034] The alkenyl group may be straight, branched, or cyclic. The alkenyl group is not particularly limited, but examples 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, etc.

[0035] The alkynyl group may be straight, branched, or cyclic. The alkynyl group is not particularly limited, but examples include 2-butynyl group, 3-pentynyl group, hexinyl group, heptynyl group, octynyl group, decinyl group, etc.

[0036] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 of the above general formula 1, the alkoxy group is not particularly limited, but examples 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, etc.

[0037] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 of the above general formula 1, the polyoxyalkylene group is not particularly limited, but examples include polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, block-phase polyoxyalkylene group of polyoxyethylene and polyoxypropylene group, random-phase polyoxyalkylene group of polyoxyethylene and polyoxypropylene group, block-phase polyoxyalkylene group of polyoxyethylene and polyoxybutylene group, and random-phase polyoxyalkylene group of polyoxyethylene and polyoxybutylene group.

[0038] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 of the above general formula 1, the organic acid group or the salt group thereof is not particularly limited, but as described above, it is preferable that it be at least one selected from the group consisting of a carboxyl group, a salt group of a carboxyl group, a sulfo group, a salt group of a sulfo group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group. Among these, it is more preferable that it be a carboxyl group, a salt group of a carboxyl group, a sulfo group, or a salt group of a sulfo group, even more preferable that it be a carboxyl group or a sulfo group, and particularly preferable that it be a sulfo group.

[0039] In the above general formula 1, where 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 (e.g., alkyl group, alkenyl group, alkynyl group), alkoxy group, polyoxyalkylene group, organic acid group or salt thereof as a substituent is, respectively, the same as described for the groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 of the above general formula 1.

[0040] In the above general formula 1, where at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted hydrocarbon group (e.g., a substituted alkyl group, a substituted alkenyl group, a substituted alkynyl group), the substituent is preferably, each independently, a deuterium atom, a halogen atom, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group or an organic acid group or a salt thereof. In addition, in the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is a substituted alkoxy group or a substituted polyoxyalkylene group, it is preferable that the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof.

[0041] In the above general formula 1, it is preferable that at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is an organic acid group or a salt group thereof, or an alkyl group substituted with an organic acid group or a salt group thereof. Among these, it is more preferable that only one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is an organic acid group or a salt group thereof, or an alkyl group substituted with an organic acid group or a salt group thereof. At this time, as an organic acid group or a group of its salt or an alkyl group substituted with an organic acid group or a group of its salt, it is more preferable that the alkyl group be a carboxyl group or a group of its salt, a sulfon group or a group of its salt, a methyl group substituted with a carboxyl group or a group of its salt, or a methyl group substituted with a sulfon group or a group of its salt; it is particularly preferable that the methyl group be a carboxyl group or a methyl group substituted with a sulfon group; and most preferable that the methyl group be a methyl group substituted with a sulfon group. According to these groups, the polishing inhibition effect of silicon nitride is further enhanced. In addition, when polishing a workpiece that includes another material (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other material to silicon nitride is further enhanced.

[0042] In the above general formula 1, it is particularly preferable that R1, R1', R2, R2', R3, R3', R4 and R4' are each independently hydrogen atoms.

[0043] In the above general formula 1, R5 is preferably a hydrogen atom or a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group, even more preferably a substituted alkyl group, and particularly preferably an alkyl group substituted with an organic acid group or a salt group thereof. In this case, as the alkyl group substituted with an organic acid group or a salt group thereof, it is preferably a methyl group substituted with a sulfon group or a salt group thereof, and particularly preferably a methyl group substituted with a sulfon group.

[0044] In the above general formula 1, R6 is preferably a hydrogen atom, or an organic acid group or its salt, more preferably a hydrogen atom, or a carboxyl group or its salt, even more preferably a hydrogen atom or a carboxyl group, and particularly preferably a hydrogen atom.

[0045] In the above general formula 1, R7 and R8 are each preferably independently a substituted or unsubstituted alkyl group, more preferably an unsubstituted alkyl group, and particularly preferably a methyl group.

[0046] Preferred specific examples of SiN polishing inhibitors include (+)-10-camphosulfonic acid, campanic acid, and ketopynic acid. Among these, (+)-10-camphosulfonic acid or campanic acid is preferred, and (+)-10-camphosulfonic acid is more preferred.

[0047] In addition, SiN polishing inhibitors can be used alone or in combination of two or more types. In addition, SiN polishing inhibitors may be synthetic products or commercially available products.

[0048] The amount (concentration) of the SiN polishing inhibitor added is not particularly limited, but it is preferable that it be 0.001 mass% or more with respect to the total mass of the polishing composition, more preferable that it be 0.01 mass% or more, even more preferable that it be 0.05 mass% or more, and particularly preferable that it be 0.15 mass% or more. Within this range, the polishing inhibition effect of silicon nitride is further enhanced. In addition, when polishing a workpiece that includes other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further enhanced. Furthermore, the amount (concentration) of the SiN polishing inhibitor added is not particularly limited, but it is preferable that it be 10 mass% or less with respect to the total mass of the polishing composition, more preferable that it be 5 mass% or less, even more preferable that it be 1 mass% or less, and particularly preferable that it be 0.5 mass% or less. Within this range, the effect of the SiN polishing inhibitor is further enhanced. This is presumed to be because the electrical conductivity does not become excessively high, and the electrical double layer of the abrasive grains and silicon nitride is not excessively compressed, so the electrostatic repulsion between the abrasive grains and silicon nitride is maintained more effectively. In addition, within this range, better dispersion stability of the slurry is also guaranteed.

[0049] Alternatively, the amount (concentration) of the SiN polishing inhibitor added is not particularly limited, but an amount equal to the desired pH value of the polishing composition may be appropriately selected. In this case, it is preferable to add an amount equal to the desired pH value of the polishing composition described below. Furthermore, while there are no particular limitations when adopting such an amount (concentration), it is particularly preferable to use it when the pH adjusting agent described below is not used in combination.

[0050] (Georip)

[0051] A polishing composition according to one embodiment of the present invention comprises cation-modified silica particles as abrasive particles. Generally, the abrasive particles act to improve the polishing speed by mechanically polishing the object to be polished, but in the case of cation-modified silica particles, polishing of silicon nitride is suppressed as described above. Furthermore, when polishing an object to be polished that includes other materials (particularly titanium nitride) in addition to silicon nitride, the cation-modified silica particles acting as abrasive particles improve the polishing speed of the other materials, thereby improving the selectivity ratio of the other materials to silicon nitride.

[0052] The type of silica particle used as a raw material for cation-modified silica particles is not particularly limited and may include fumed silica, colloidal silica, etc., but is preferably colloidal silica. Examples of methods for manufacturing colloidal silica include the sodium silicate method and the sol-gel method. Colloidal silica produced by any of these methods is suitable for use. However, from the perspective 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 that have the property of diffusing in semiconductors, or corrosive ions such as chloride ions. The production of colloidal silica by the sol-gel method can be carried out using conventionally known methods. Specifically, colloidal silica can be obtained by using a hydrolyzable silicon compound (e.g., alkoxysilane or its derivative) as a raw material and performing a hydrolysis and condensation reaction.

[0053] As for the cation-modified silica particles, known ones may be appropriately selected and used. Additionally, cation-modified silica particles may be manufactured by a method appropriately selected from known manufacturing methods, and said cation-modified silica particles may be used.

[0054] As for the cationic modified silica particles, it is preferable that they be cationic modified colloidal silica. Furthermore, as for the colloidal silica having cationic groups (cationic modified colloidal silica), colloidal silica with amino groups immobilized on the surface is preferably cited. As a method for manufacturing such colloidal silica having cationic groups, a method of immobilizing a silane coupling agent having amino groups, such as aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminopropyldimethylethoxysilane, aminopropylmethyldiethoxysilane, and aminobutyltriethoxysilane, as described in Japanese Patent Publication No. 2005-162533, on the surface of silica particles may be cited. By doing so, colloidal silica with amino groups immobilized on the surface (amino group modified colloidal silica) can be obtained. According to their cationic modified colloidal silica, the polishing inhibition effect of silicon nitride is further enhanced. Furthermore, when polishing a workpiece containing other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved.

[0055] The shape of the cation-modified silica particles is not particularly limited and may be spherical or non-spherical. Specific examples of non-spherical shapes include polygonal prisms such as triangular or square prisms, cylindrical shapes, sack-shaped shapes where the center of the cylindrical part is bulging more than the ends, donut-shaped shapes where the center of the disc is penetrated, plate-shaped shapes, so-called cocoon-shaped shapes having a constriction in the center, so-called associative spherical shapes where multiple particles are integrated, so-called star candy shapes having multiple protrusions on the surface, rugby ball shapes, and various other shapes, and are not particularly limited. Among these, when polishing a workpiece that further contains silicon oxide as another material, a cocoon-shaped shape is preferred from the perspective of suppressing the silicon oxide polishing speed.

[0056] The average primary particle size of the cation-modified silica particles is not particularly limited, but it is preferable that it be 5 nm or larger, more preferable that it be 7 nm or larger, even more preferable that it be 10 nm or larger, and particularly preferable that it be 25 nm or larger. Within this range, when polishing a workpiece that includes other materials (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved. In addition, the average primary particle size of the cation-modified silica particles is not particularly limited, but it is preferable that it be 120 nm or smaller, more preferable that it be 80 nm or smaller, and even more preferable that it be 50 nm or smaller. Within this range, the polishing inhibition effect of silicon nitride is further improved. In addition, the value of the average primary particle size 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 spherical. More specifically, the average primary particle size of the cation-modified silica particles can be calculated from the specific surface area of ​​the cation-modified silica particles measured by the BET method using Micro Meritics’ “Flow Sorb II 2300” and the density of the cation-modified silica particles.

[0057] The average secondary particle size of the cation-modified silica particles is not particularly limited, but it is preferably 10 nm or larger, more preferably 20 nm or larger, even more preferably 30 nm or larger, and particularly preferably 50 nm or larger. Within this range, when polishing a workpiece containing other materials (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved. Additionally, the average secondary particle size of the cation-modified silica particles is not particularly limited, but it is preferably 250 nm or smaller, more preferably 200 nm or smaller, even more preferably 150 nm or smaller, and particularly preferably 100 nm or smaller. Within this range, the polishing inhibition effect of silicon nitride is further improved. In addition, the value of the average secondary particle size of the cation-modified silica particles can be calculated by the dynamic light scattering method, represented by the laser diffraction scattering method, using, for example, the dynamic light scattering particle size and particle size distribution device UPA-UTI151 manufactured by Nikkiso Co., Ltd.

[0058] The degree of aggregation of the cationic modified silica particles is not particularly limited, but it is preferably 5 or less, more preferably 3 or less, and even more preferably 2.5 or less. Within this range, the polishing inhibition effect of silicon nitride is further improved. In addition, the degree of aggregation of the cationic modified silica particles is preferably 1 or more, and more preferably 1.2 or more. Within this range, when polishing a workpiece that includes other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of other materials to silicon nitride is further improved. In addition, the degree of aggregation of the cationic modified silica particles is obtained by dividing the value of the average secondary particle size of the cationic modified silica particles by the value of the average primary particle size.

[0059] The number of silanol groups per unit surface area of ​​cation-modified silica particles (hereinafter also referred to as "silanol group density") is not particularly limited, but is 0 / nm2 It is desirable to exceed , and 0.2 pieces / nm 2 It is more desirable to have more than 1 / nm 2 It is more desirable to have an ideal value, and 1.4 pieces / nm 2 It is particularly desirable that the above range is achieved. Within this range, the dispersibility of the abrasive particles is improved, and when polishing a workpiece containing other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity of the other materials relative to silicon nitride is further enhanced. Furthermore, the silanol group density of the cationic modified silica particles is 10 / nm 2 It is desirable that it be less than or equal to 6 pieces / nm 2 It is more desirable that it be less than or equal to 4 / nm 2 It is more desirable that it be less than or equal to 2 / nm 2 It is particularly desirable that it be less than or equal to the following. 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.

[0060] In the following formula, C is the total mass of the cation-modified silica particles, and S is the BET specific surface area of ​​the cation-modified silica particles. First, 1.50 g of cation-modified silica particles as a solid are placed in a 200 ml beaker, 100 ml of pure water is added to form a slurry, and then 30 g of sodium chloride is added to dissolve it. Next, 1 N 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 becomes 150 ml. For this slurry, an automatic titration device (manufactured by Hiranuma Sangyo Co., Ltd., COM-1700) is used, and 0.1N sodium hydroxide is used at 25°C to adjust the pH to 4.0. Additionally, the volume V[L] of 0.1N sodium hydroxide solution required to raise the pH from 4.0 to 9.0 by pH titration is measured. The silanol group density can be calculated by the following formula.

[0061]

[0062] Among the above formulas,

[0063] ρ is the silanol group density (number / nm) 2 Representing );

[0064] c represents the concentration (mol / L) of the sodium hydroxide solution used in the titration;

[0065] V represents the volume (L) of sodium hydroxide solution required to raise the pH from 4.0 to 9.0;

[0066] N A represents Avogadro's constant (units / mol);

[0067] C represents the total mass (solid content) (g) of the cation-modified silica particles;

[0068] S is the weighted average value of the BET specific surface area of ​​the cation-modified silica particles (nm 2 / g) represents.

[0069] In addition, the BET specific surface area of ​​cation-modified silica particles can be measured using "Flow Sorb II 2300" manufactured by Micro Meritics.

[0070] The zeta potential of the cationic modified silica particles in the polishing composition is not particularly limited, but it is preferable that it be a positive value. Within this range, the polishing inhibition effect of silicon nitride is further enhanced. Furthermore, when polishing an object containing other materials (particularly titanium nitride) in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is further improved. It is presumed that this is because the positive charge of the cationic modified silica particles becomes stronger, the electrostatic repulsion between the cationic modified silica particles and the silicon nitride film becomes stronger, and the scraping action and scraping frequency of the silicon nitride film of the abrasive particles become weaker. In the same regard, the zeta potential of the cationic modified silica particles in the polishing composition is generally a positive value, and as the value increases, it is preferable that it be, for example, 10 mV or higher, more preferable that it be 20 mV or higher, and particularly preferable that it be 30 mV or higher. In addition, it is preferable that the zeta potential of the cation-modified silica particles in the polishing composition be, for example, 60 mV or less. The zeta potential of the cation-modified silica particles in the polishing composition can be calculated by providing the polishing composition to the ELS-Z2 manufactured by Otsuka Denshi Co., Ltd., measuring the laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C, and interpreting the obtained data using Smoluchowski's equation.

[0071] The size (average primary particle diameter, average secondary particle diameter), degree of association, silanol group density, and zeta potential in the abrasive composition of the cation-modified silica particles can be appropriately controlled by selecting a method for manufacturing the cation-modified silica particles. In particular, regarding the silanol group density, it is suitable to control it under heat treatment conditions such as calcination, for example.

[0072] In addition, cation-modified silica particles can be used alone or in combination of two or more types.

[0073] The amount (concentration) of cationic modified silica particles added is not particularly limited, but it is preferable that it be 0.001 mass% or more with respect to the total mass of the polishing composition, more preferable that it be 0.01 mass% or more, and even more preferable that it be 0.1 mass% or more. Within this range, when polishing a workpiece that includes other materials (especially titanium nitride) in addition to silicon nitride, the selectivity ratio of other materials to silicon nitride is further improved. In addition, the amount (concentration) of cationic modified silica particles added is not particularly limited, but it is preferable that it be 30 mass% or less with respect to the total mass of the polishing composition, more preferable that it be 10 mass% or less, and even more preferable that it be 5 mass% or less. Within this range, the polishing inhibition effect of silicon nitride is further improved.

[0074] A polishing composition according to one embodiment of the present invention may include other abrasive particles in addition to cation-modified silica particles. The other abrasive particles may be any of inorganic particles, organic particles, and organic-inorganic composite particles other than cation-modified silica particles. Examples of inorganic particles other than cation-modified silica particles include surface-unmodified silica particles, anionic-modified silica particles, particles containing metal oxides such as alumina particles, ceria particles, and titania particles, silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles.

[0075] However, in the polishing composition according to one embodiment of the present invention, it is preferable that the amount (concentration) of other abrasive particles added is as small as possible, and it is particularly preferable that it does not substantially contain other abrasive particles. In addition, in this specification, "substantially contains other abrasive particles" means that the amount (concentration) of other abrasive particles added is less than 0.001 mass% with respect to the total mass of the polishing composition.

[0076] (Silicon oxide polishing inhibitor)

[0077] A polishing composition according to one embodiment of the present invention preferably further comprises a compound that inhibits the polishing of silicon oxide (also referred to herein as a "silicon oxide polishing inhibitor"). The silicon oxide polishing inhibitor is a compound represented by the following general formula 2.

[0078]

[0079] In the above general formula 2,

[0080] X1 is, CR 11 R 11 or C=O and,

[0081] X2 is, CR 12 R 12 or C=O and,

[0082] X3 is CR 13 R 13 or C=O and,

[0083] X4 is CR 14 R 14 or C=O and,

[0084] R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14Each is independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3, and

[0085]

[0086] 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, and

[0087] * is a bonding hand that bonds to the ring-constituent nitrogen atom (N) of the above general formula 2, and

[0088] R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 , R 14 ' and R 15 In the case where at least one of the groups is substituted, the substituents are, respectively, a deuterium atom, a halogen atom, an unsubstituted oxy hydrocarbon group, or an unsubstituted polyoxyalkylene group.

[0089] The silicon oxide polishing inhibitor acts to inhibit the polishing of silicon oxide, which is another material. Furthermore, when polishing a workpiece that includes, in addition to silicon oxide, other materials other than silicon oxide (particularly titanium nitride), it acts to improve the selectivity ratio of the other materials other than silicon oxide to silicon oxide. Although the details of this reason are unclear, it is speculated as follows. It has been confirmed that the silicon oxide polishing inhibitor is adsorbed onto the SiO2 sensor using a QCM (Quartz Crystal Microbalance). From this, the silicon oxide polishing inhibitor protects the silicon oxide film from the abrasive particles by adsorbing onto the silicon oxide film (silicon oxide surface) and thereby suppressing collisions between the abrasive particles and the silicon oxide film. Furthermore, this mechanism is based on speculation, and its accuracy does not affect the technical scope of the present invention.

[0090] In a preferred embodiment of the present invention, the polishing composition comprises, in addition to the cation-modified silica particles and the above-mentioned SiN polishing inhibitor, a silicon oxide polishing inhibitor. Since the SiN polishing inhibitor acts on silicon nitride and the silicon oxide polishing inhibitor acts on silicon oxide, and each action is well exhibited, the polishing composition thereby enables the improvement of the selectivity ratio of other materials to silicon nitride and the improvement of the selectivity ratio of materials other than silicon oxide to silicon oxide to coexist.

[0091] R of the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 And R of the above general formula 3 15 In this case, the halogen atoms are not particularly limited, but examples include F, Cl, Br, and I.

[0092] R of the above general formula 2 10, R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 And R of the above general formula 3 15 In this case, the hydrocarbon group is not particularly limited, but examples include alkyl groups, alkenyl groups, or alkynyl groups. The alkyl groups, alkenyl groups, or alkynyl groups are not particularly limited, but examples include those similar to those exemplified in the description of the groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 of General Formula 1 above.

[0093] R of the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 In ', the oxy hydrocarbon group refers to a group represented by "-OR", and the said R" represents a hydrocarbon group. Additionally, the hydrocarbon group is R of the above general formula 2. 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 And R of the above general formula 3 15 It is the same as the explanation in [that].

[0094] R of the above general formula 2 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R14 In this case, the polyoxyalkylene group is not particularly limited, but, for example, 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 of the above general formula 1 can be cited.

[0095] In the above general formula 2, R 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 In the case where at least one of ' is substituted, or in the above general formula 3, R 15 In the case where is a substituted group, the halogen atom as a substituent is not particularly limited, but examples include F, Cl, Br, and I, etc. Additionally, the oxyhydrocarbon group and the polyoxyalkylene group as substituents are each R of General Formula 2 above. 10 , R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 It is the same as their explanation of the energy in '.

[0096] In the above general formula 2, R 10 It is preferable that the suffix is ​​represented by the above general formula 3. In this case, R 15 It is preferable that the group be a substituted or unsubstituted hydrocarbon group, more preferable that the group be an unsubstituted hydrocarbon group, even more preferable that the group be an unsubstituted alkyl group or an unsubstituted alkenyl group, even more preferable that the group be an unsubstituted alkyl group having 1 to 6 carbon atoms or an unsubstituted alkenyl group having 2 to 6 carbon atoms, and particularly preferable that the group be a methyl group or a vinyl group.

[0097] In the above general formula 2, R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 It is more desirable that all of them be hydrogen atoms.

[0098] Specific examples of silicon oxide polishing inhibitors are not particularly limited, but examples include 4-acetylmorpholine, 3-morpholone, N-methyl-2-morpholone, 4-vinyl-3-morpholone, 4-acryloylmorpholine, 4-methacryloylmorpholine, etc. Among these, 4-acetylmorpholine and 4-acryloylmorpholine are preferred. Furthermore, 4-acetylmorpholine is more preferred from the perspective of improving the selectivity ratio of other materials to silicon nitride, and 4-acryloylmorpholine is more preferred from the perspective of improving the selectivity ratio of other materials to silicon oxide.

[0099] Silicon oxide polishing inhibitors can be used alone or in combination of two or more types. Additionally, silicon oxide polishing inhibitors may be synthetic products or commercially available products.

[0100] The amount (concentration) of the silicon oxide polishing inhibitor added is not particularly limited, but it is preferable that it be 0.001 mass% or more with respect to the total mass of the polishing composition, more preferable that it be 0.01 mass% or more, even more preferable that it be 0.1 mass% or more, and particularly preferable that it be 0.25 mass% or more. Within this range, the polishing inhibition effect of silicon oxide is further enhanced. Furthermore, when polishing a workpiece that includes, in addition to silicon oxide, another material other than silicon oxide (particularly titanium nitride), the selectivity ratio of the other material other than silicon oxide to silicon oxide is further enhanced. Additionally, the amount (concentration) of the silicon oxide polishing inhibitor added is not particularly limited, but it is preferable that it be 10 mass% or less with respect to the total mass of the polishing composition, more preferable that it be 5 mass% or less, even more preferable that it be 1 mass% or less, and particularly preferable that it be 0.5 mass% or less. Within this range, the effect of the silicon oxide polishing inhibitor is further enhanced. It is presumed that this is because the electrical conductivity does not become excessively high and the electrical double layer of the abrasive grains and silicon oxide is not excessively compressed, so the electrostatic repulsion between the abrasive grains and silicon oxide is maintained more effectively. In addition, within this range, better dispersion stability of the slurry is also guaranteed.

[0101] (Oxidizing agent)

[0102] A polishing composition according to one embodiment of the present invention preferably further comprises an oxidizing agent. The oxidizing agent acts to improve polishing characteristics, such as by oxidizing the film surface of a material other than a silicon nitride film to improve the polishing speed of the other material or to improve the surface quality of the object to be polished after polishing.

[0103] As for the oxidizing agent, examples include hydrogen peroxide, sodium peroxide, barium peroxide, ozone water, silver(II) salts, iron(III) salts, permanganate, chromic acid, dichromate, peroxodisulfate, peroxophosphate, peroxosulfuric acid, peroxoboric acid, performic acid, peracetic acid, perbenzoic acid, perphthalic acid, hypochlorous acid, hypobromonic acid, hypoiodic acid, chloric acid, hypochlorous acid, perchloric acid, bromic acid, iodic acid, periodic acid, persulfuric acid, dichloroisocyanuric acid, and their salts. Among these, hydrogen peroxide is preferred from the perspective of handling and safety. Additionally, the oxidizing agent may be used alone or in combination of two or more types.

[0104] The amount (concentration) of the oxidizing agent added is not particularly limited, but it is preferable that it be 0.001 mass% or more with respect to the total mass of the polishing composition, more preferable that it be 0.01 mass% or more, and even more preferable that it be 0.1 mass% or more. Within this range, the oxidation reaction of materials other than the silicon nitride film proceeds more sufficiently, and the selectivity ratio of other materials to silicon nitride is further improved. In addition, the amount (concentration) of the oxidizing agent added is not particularly limited, but it is preferable that it be 10 mass% or less with respect to the total mass of the polishing composition, more preferable that it be 5 mass% or less, and even more preferable that it be 3 mass% or less. Within this range, the effect of the reduction in abrasive particle concentration due to the addition of the oxidizing agent is smaller, the polishing speed of materials other than the silicon nitride film can be maintained more well, and the selectivity ratio of other materials to silicon nitride is further improved.

[0105] (pH adjuster)

[0106] A polishing composition according to one embodiment of the present invention preferably further comprises a pH adjusting agent. The pH adjusting agent acts to improve the polishing speed by improving the chemical polishing effect on the surface to be polished by adjusting the pH of the polishing composition to an appropriate range, or to improve the dispersion stability of the polishing composition.

[0107] In addition, in this specification, the above SiN polishing inhibitor is not included in the pH adjuster.

[0108] The pH adjuster is not particularly limited as long as it is a compound having a pH adjusting function, and for example, acidic or basic compounds may be used. Here, a basic compound refers to a compound that has the function of raising the pH of water when dissolved in water, and acts to raise the pH of the polishing composition when added to the polishing composition.

[0109] As for the acid, either an inorganic acid or an organic acid may be used. As for the inorganic acid, there are no particular limitations, but examples include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphoric acid, and phosphoric acid. As for the organic acid, there are no particular limitations, but examples include 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-octoic 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, and other carboxylic acids.

[0110] Basic compounds are not particularly limited, but examples include hydroxides of alkali metals or Group 2 elements, ammonia, etc. Specific examples of alkali metal hydroxides include potassium hydroxide (KOH) and sodium hydroxide (NaOH). Specific examples of Group 2 element hydroxides include calcium hydroxide (Ca(OH)2).

[0111] Among these, inorganic acids or basic compounds are preferred from the perspective of adjusting to the optimal pH range described below. Furthermore, as an inorganic acid, nitric acid is more preferred. As a basic compound, hydroxides of alkali metals or Group 2 elements are more preferred, and hydroxides of alkali metals are even more preferred. Also, as a pH adjuster, nitric acid or potassium hydroxide is particularly preferred, and potassium hydroxide is extremely preferred.

[0112] In addition, pH adjusters can be used alone or in combination of two or more.

[0113] The amount (concentration) of the pH adjuster added can be appropriately selected to be equal to the desired pH value of the polishing composition, and it is preferable to add an amount equal to the desirable pH value of the polishing composition described below.

[0114] (pH)

[0115] The pH of the polishing composition according to one embodiment of the present invention is not particularly limited. However, the lower limit of the pH is preferably 1 or higher, more preferably 1.5 or higher, and even more preferably 2 or higher. Within this range, the polishing inhibition effect of silicon nitride is enhanced. The reason for this is presumed as follows. Within this range, electrical conductivity does not become excessively high, and the electrical double layer of abrasive grains and silicon nitride is not excessively compressed. Consequently, the electrostatic repulsion between the abrasive grains and silicon nitride is maintained more effectively. Furthermore, the possibility of deterioration of consumable components, such as polishing devices or contacting polishing pads, is further reduced. Additionally, the upper limit of the pH is preferably 12 or lower. Within this range, corrosion becomes less likely to occur, making it possible to apply to polishing targets containing various materials. Furthermore, safety is further improved, and handling becomes easier. In addition, the upper limit of the pH is more preferably less than 7, more preferably 5 or less, more preferably 4 or less, particularly preferably less than 4, more particularly preferably 3.5 or less, and extremely preferably 3 or less. Within this range, the polishing inhibition effect of silicon nitride is higher. The reason for this is presumed as follows. When the pH is within the above range, the surface potential of silicon nitride becomes positive, and the positive value increases. In addition, generally, the zeta potential of the abrasive grain also becomes positive, and the positive value increases. This is because the electrostatic repulsion between the abrasive grain and silicon nitride becomes stronger, and the scraping action of the abrasive grain can be further weakened. Furthermore, the pH value of the polishing composition can be evaluated by a pH meter (product name: LAQUA (registered trademark) manufactured by Horiba Seisakusho Co., Ltd.).

[0116] (Electrical conductivity modifier)

[0117] A polishing composition according to one embodiment of the present invention may further include an electrical conductivity modifier. The electrical conductivity modifier acts to improve the effect of inhibiting the polishing speed of silicon nitride or to improve the dispersion stability of the polishing composition by adjusting the electrical conductivity of the polishing composition to an appropriate range.

[0118] As an electrical conductivity modifier, any compound having an electrical conductivity modulating function is not particularly limited, and, for example, a salt compound may be used.

[0119] Examples of salt compounds include salts of acids and salts of basic compounds. Salts of acids may be either organic or inorganic salts. Inorganic salts are not particularly limited, but 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. Additionally, salts of basic compounds are not particularly limited, but examples include potassium chloride, sodium chloride, potassium bromide, potassium iodide, and ammonium citrate. Salt compounds may be used individually or in combination of two or more types.

[0120] The amount (concentration) of the electrical conductivity modifier added can be appropriately selected to be equal to the desired electrical conductivity of the polishing composition, and it is preferable to add an amount equal to the desired electrical conductivity value of the polishing composition described below.

[0121] (Electrical conductivity)

[0122] The electrical conductivity (EC) of the polishing composition according to one embodiment of the present invention is not particularly limited. However, the lower limit of the electrical conductivity is preferably 30 μS / cm or higher, more preferably 0.1 mS / cm or higher, and even more preferably 0.6 mS / cm or higher. Within this range, the polishing inhibition effect of silicon nitride is enhanced. This is presumed to be because, at low electrical conductivity, the electrostatic repulsion acting between the abrasive grains and silicon nitride is maintained at a higher state. Furthermore, the upper limit of the electrical conductivity is preferably less than 10 mS / cm. Within this range, the dispersion stability of the polishing composition is further improved. Furthermore, the upper limit of the electrical conductivity is more preferably 2 mS / cm or lower, and even more preferably 1 mS / cm or lower. Within this range, the polishing speed inhibition effect of the silicon nitride film is further enhanced. It is presumed that this is because the electrical conductivity does not increase excessively, and the electrostatic repulsion between the abrasive grains and the silicon nitride film does not weaken. In this regard, an example of a desirable range of electrical conductivity is a range of 30 μS / cm or more and 2 mS / cm or less. In addition, the electrical conductivity of the abrasive composition can be evaluated by a benchtop electrical conductivity meter (manufactured by Horiba Seisakusho Co., Ltd., Model No.: DS-71).

[0123] In addition, electrical conductivity can be improved by increasing the amount of, for example, acid, basic compound, or salt compound thereof. Specifically, it may be controlled by the amount of each component other than the electrical conductivity modifier, or by adding more electrical conductivity modifier.

[0124] (Dispersed)

[0125] A polishing composition according to one embodiment of the present invention further comprises a dispersion medium (solvent). The dispersion medium comprises water. The dispersion medium acts to disperse or dissolve each component.

[0126] As for the dispersion medium, there are no particular restrictions as long as it contains water. The water content in the dispersion medium is not particularly limited, but it is preferable that it be 50 mass% or more relative to the total mass of the dispersion medium, more preferable that it be 90 mass% or more, and even more preferable that it be water only. From the perspective of preventing contamination of the object to be cleaned or interference with the action of other components, it is preferable that the water contains as few impurities as possible, and water with a total transition metal ion content of 100 ppb or less is preferred. Here, the purity of the water can be increased by operations such as the removal of impurity ions using an ion exchange resin, the removal of foreign matter by a filter, or distillation. Specifically, as the water, it is preferable to use deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc.

[0127] In addition, the dispersion medium may be a mixed solvent of water and an organic solvent if it can improve the dispersibility or solubility of each component. The organic solvent is not particularly limited, and any known organic solvent may be used. When using a mixed solvent of water and an organic solvent, it is preferable that the organic solvent be miscible with water. When using an organic solvent, the mixed solvent may be prepared by mixing water and the organic solvent, and then each component may be added to the mixed solvent and mixed, or each component may be dispersed or dissolved in the organic solvent and then mixed with water. In addition, the organic solvent may be used alone or in combination of two or more types.

[0128] (Other ingredients)

[0129] A polishing composition according to one embodiment of the present invention may further include other components to the extent that it does not impede the effects of the present invention. The other components are not particularly limited, but may be appropriately selected from various components used in known polishing compositions, such as wetting agents, surfactants, chelating agents, preservatives, antifungal agents, dissolved gases, reducing agents, etc.

[0130] (Object to be polished)

[0131] A polishing composition according to one embodiment of the present invention is not particularly limited and can be applied to known polishing targets used in the CMP field. For this reason, the form of the polishing target is not particularly limited, but a layer that is a planar member is preferred, a substrate including said layer is more preferred, and a semiconductor substrate is even more preferred. Examples include a substrate composed of a single layer, or a substrate including a layer to be polished and another layer (e.g., a support layer or another functional layer).

[0132] In order to more clearly demonstrate the effects of the present invention, it is particularly preferable that the surface to be polished comprises silicon nitride. That is, the polishing composition according to one embodiment of the present invention is preferably used to polish a polishing object comprising silicon nitride. Furthermore, it is preferable that the surface to be polished comprises other materials in addition to silicon nitride. This is because the polishing composition according to one embodiment of the present invention exhibits a high polishing inhibition effect with respect to silicon nitride while exhibiting a high polishing speed with respect to other materials, thereby enabling a high selectivity ratio of other materials to silicon nitride. The other materials are not particularly limited, but it is preferable that the polishing object further comprises, for example, silicon-containing materials other than silicon nitride, or components including metals, metal oxides, or metal nitrides.

[0133] Silicon-containing materials other than silicon nitride are not particularly limited, but examples include materials having silicon-oxygen bonds (e.g., silicon oxide, etc.), materials having silicon-silicon bonds (e.g., polysilicon, etc.), and materials having silicon-nitrogen bonds other than silicon nitride. Here, materials having silicon-oxygen bonds are not particularly limited, but examples include silicon oxide, BD (black diamond: SiOCH), FSG (fluorosilicate glass), HSQ (hydrogen silsesquioxane), CYCLOTENE, SiLK, MSQ (methyl silsesquioxane), etc. In addition, materials to be polished having silicon-silicon bonds are not particularly limited, but examples include 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, etc. In addition, materials having silicon-nitrogen bonds other than silicon nitride are not particularly limited, but examples include silicon carbonitride (SiCN). Among these, materials having silicon-silicon bonds are preferred, and polysilicon is more preferred, from the perspective that the polishing composition according to one embodiment of the present invention polishes at a higher polishing speed and further improves the selectivity ratio of other materials to silicon nitride. Furthermore, among these, if the polishing composition further includes the silicon oxide polishing inhibitor mentioned above, materials having silicon-oxygen bonds are preferred, and silicon oxide is more preferred. This is because the effect of improving the selectivity ratio of other materials to silicon nitride and the effect of improving the selectivity ratio of other materials other than silicon oxide to silicon oxide are compatible.In addition, the silicon oxide-containing film is not particularly limited, but examples include a TEOS (Tetraethyl Orthosilicate) type silicon oxide film (also referred to as "TEOS-SiO2" in this specification) produced using tetraethyl orthosilicate as a precursor, an HDP (High Density Plasma) film, a USG (Undoped Silicate Glass) film, a PSG (Phosphorus Silicate Glass) film, a BPSG (Boron-Phospho Silicate Glass) film, an RTO (Rapid Thermal Oxidation) film, etc. Furthermore, as the silicon oxide, it is particularly preferred to be TEOS-SiO2. Therefore, as a polishing target, it is particularly desirable to have a polishing target that further includes silicon oxide (preferably TEOS-SiO2) in addition to silicon nitride.

[0134] In addition, the metal is not particularly limited, but examples include copper, aluminum, hafnium, cobalt, nickel, titanium, tungsten, and alloys thereof. The metal oxide is not particularly limited, but examples include alumina. The metal nitride is not particularly limited, but examples include titanium nitride and tantalum nitride. Among these, in order to further improve the selectivity ratio of the other material to silicon nitride by polishing at a higher polishing speed with the polishing composition according to one embodiment of the present invention, the other material is preferably a metal nitride, and titanium nitride is more preferably. Accordingly, as the polishing target, it is particularly preferred to be a polishing target that further includes titanium nitride in addition to silicon nitride.

[0135] And, in this regard, it is particularly desirable that the workpiece for polishing further comprises silicon oxide (preferably TEOS-SiO2) and titanium nitride in addition to silicon nitride.

[0136] (Selectivity ratio of other materials for silicon nitride)

[0137] In a polishing method using a polishing composition according to one embodiment of the present invention, when polishing an object to be polished that includes another material in addition to silicon nitride, the selectivity ratio of the other material to silicon nitride is not particularly limited, but is preferably higher. For example, when the other material is titanium nitride, the selectivity ratio of titanium nitride to silicon nitride is not particularly limited, but is preferably 40 or higher, more preferably 50 or higher, even more preferably 70 or higher, even more preferably 90 or higher, particularly preferably 100 or higher, even more particularly preferably 110 or higher, extremely preferably 150 or higher, and most preferably 180 or higher. Furthermore, for example, when the other material is silicon oxide, the selectivity ratio of titanium nitride to silicon oxide is not particularly limited, but is preferably greater than 15, more preferably 20 or higher, and even more preferably 25 or higher. In addition, the selectivity ratio of other materials to silicon nitride can be obtained by dividing the polishing rate of other materials by the polishing rate of silicon nitride.

[0138] Method for manufacturing a polishing composition

[0139] Another embodiment of the present invention relates to a method for preparing a polishing composition comprising mixing cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water.

[0140] In addition, in the method for preparing a polishing composition according to one embodiment of the present invention, the silicon oxide polishing inhibitor described above or other components may be further mixed. From this, a method for preparing a preferred embodiment of the present invention may include, for example, further mixing a compound represented by General Formula 2.

[0141] The mixing method when mixing each component is not particularly limited, and known methods may be appropriately used. In addition, the mixing temperature is not particularly limited, but is generally preferred to be 10 to 40°C, and may be heated to increase the dissolution rate. In addition, the mixing time is not particularly limited.

[0142] Furthermore, regarding the method for manufacturing the polishing composition, the preferred form (type, characteristics, structure, amount of addition, etc.) of each component is the same as the description of each component regarding the polishing composition. In addition, regarding the various features, including the preferred characteristics of the polishing composition being manufactured, is also the same as the description regarding the polishing composition.

[0143] <Polishing Method>

[0144] Another embodiment of the present invention relates to a polishing method for polishing an object to be polished by using the polishing composition described above, or by manufacturing a polishing composition by the manufacturing method described above, and using the polishing composition manufactured said to be polished.

[0145] In the polishing method, the object to be polished is the same as described in the explanation regarding the polishing composition.

[0146] As for the grinding device and grinding conditions, there are no particular limitations, and known devices and conditions may be appropriately used.

[0147] A general polishing device may be used, equipped with a holder that supports the workpiece to be polished and a motor capable of changing the rotational speed, and having a polishing plate to which a polishing pad (polishing cloth) can be attached. As the polishing device, either a single-sided polishing device or a double-sided polishing device may be used. As the polishing pad, general non-woven fabric, polyurethane, porous fluoropolymer, etc., may be used without particular restrictions. It is preferable that the polishing pad be formed with grooves to collect the polishing liquid.

[0148] The polishing conditions are not particularly limited, and appropriate conditions can be set according to the characteristics of the polishing composition and the object to be polished. The polishing load (polishing pressure, processing pressure) is not particularly limited, but generally, it is preferable for it to be 0.1 psi or more and 10 psi or less per unit area, more preferable for it to be 0.5 psi or more and 8 psi or less, and even more preferable for it to be 1 psi or more and 6 psi or less. Within this range, it is possible to obtain a high polishing speed while further suppressing defects such as damage to the substrate due to the load or scratches on the surface. The platen rotation speed and carrier rotation speed are not particularly limited, but generally, it is preferable for them to be 10 rpm or more and 500 rpm or less, more preferable for 20 rpm or more and 300 rpm or less, and even more preferable for 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 continuous supply using a pump, etc. (flow type) may be adopted. The supply amount (flow rate of the polishing composition) of the polishing composition should be sufficient to cover the entire object to be polished and is not particularly limited, but generally, it is preferable to be between 100 mL / min and 5000 mL / min. The polishing time should be set appropriately to obtain the desired polishing result and is not particularly limited, but generally, it is preferable to be between 5 seconds and 180 seconds. In addition, it is preferable to perform polishing using in-situ dressing. Here, in-situ dressing refers to a technique of dressing the saw blade of the pad while polishing. In-situ dressing can further improve the uniformity of the polishing speed with respect to the polishing time, thereby further improving the controllability of the polishing. As an in-situ dressing component, it is preferable to use a conditioner such as a diamond dresser.

[0149] After the polishing is finished, the polished workpiece may have its surface dried by removing water droplets attached to the surface using a spin dryer or air blower, etc., after washing with water.

[0150] In a polishing method according to one embodiment of the present invention, when polishing a workpiece comprising additional materials in addition to silicon nitride, the selectivity ratio of the other materials to silicon nitride is not particularly limited, but a higher ratio is preferred. The preferred range of the selectivity ratio of titanium nitride to silicon nitride is the same as described above regarding the polishing composition. Furthermore, the preferred range of the selectivity ratio of titanium nitride to silicon oxide is the same as described above regarding the polishing composition.

[0151] Method for manufacturing a semiconductor substrate

[0152] Another embodiment of the present invention relates to a method for manufacturing a semiconductor substrate, wherein the object to be polished is a substrate material, and the method comprises a process (polishing process) for polishing said substrate material by the polishing method described above. That is, the embodiment is a method for manufacturing a semiconductor substrate, wherein the substrate material used to form a semiconductor substrate, which is an object to be polished including titanium nitride, is polished using the polishing composition described above, or by manufacturing a polishing composition by the manufacturing method described above, and polishing said polishing composition.

[0153] In addition, regarding other processes in the manufacturing method, processes that can be employed in known semiconductor substrate manufacturing methods may be appropriately employed.

[0154] Although embodiments of the present invention have been described in detail, it is clear that this is illustrative and exemplary and is not limiting, and that the scope of the present invention should be interpreted by the appended claims.

[0155] The present invention includes, but is not limited to, the following embodiments and forms:

[0156] 1. A polishing composition comprising cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water;

[0157] 2. The non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is a compound represented by General Formula 1, and is a polishing composition described in 1.;

[0158] 3. The polishing composition described in 2. above, wherein at least one of Z1, Z2, Z3 and Z4 is C=O in the above general formula 1;

[0159] 4. A polishing composition described in 2. or 3., wherein, in the above general formula 1, at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is an organic acid group or a salt group thereof, or an alkyl group substituted with an organic acid group or a salt group thereof;

[0160] 5. A polishing composition described in any one of claims 1 to 4, wherein the organic acid group or the salt group thereof is at least one selected from the group consisting of a carboxyl group, a salt group of a carboxyl group, a sulfonate group, a salt group of a sulfonate group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group;

[0161] 6. A polishing composition described in any one of claims 1 to 5, wherein the zeta potential of the cation-modified silica particles is a positive value;

[0162] 7. A polishing composition described in any one of claims 1 to 6, further comprising a compound represented by the above general formula 2;

[0163] 8. A polishing composition described in any one of claims 1 to 7, further comprising an oxidizing agent;

[0164] 9. A polishing composition described in any one of claims 1 to 8, having a pH of less than 7;

[0165] 10. A polishing composition described in any one of claims 1 to 9, having an electrical conductivity of 30 μS / cm or more and 2 mS / cm or less;

[0166] 11. A polishing composition described in any one of claims 1 to 10, used for polishing a workpiece comprising silicon nitride;

[0167] 12. A polishing composition described in 11. used for polishing a workpiece further comprising titanium nitride;

[0168] 13. A polishing composition described in 11. or 12. used for polishing a workpiece further comprising silicon oxide;

[0169] 14. A method for preparing a polishing composition comprising mixing cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water;

[0170] 15. A method for preparing a polishing composition described in 14, comprising further mixing a compound represented by the above general formula 2;

[0171] 16. Using the polishing composition described in any one of claims 1 to 13 above, or,

[0172] A polishing composition is prepared by the manufacturing method described in 14. or 15. above, and the prepared polishing composition is used,

[0173] A polishing method for polishing an object;

[0174] 17. 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 described in 16.

[0175] [Example]

[0176] The present invention will be explained in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Also, unless otherwise noted, “%” and “parts” mean “mass%” and “mass parts,” respectively. Furthermore, in the following examples, unless otherwise noted, operations were performed under conditions of room temperature (25°C) and relative humidity of 40 to 50% RH.

[0177] <Preparation of Abrasive Composition 1>

[0178] (Abrasive composition 1)

[0179] Colloidal silica A, which is colloidal silica with amino groups immobilized as abrasive particles on the surface in pure water as a dispersion medium (average primary particle size 35 nm; average secondary particle size 70 nm; silanol group density 1.5 / nm 2 A polishing composition 1 was prepared by adding (+)-10-camphosulfonic acid as a SiN polishing inhibitor, hydrogen peroxide as an oxidizing agent, and nitric acid as a pH adjusting agent.

[0180] Here, the amount of colloidal silica A added as abrasive particles was set to 3 mass% relative to the polishing composition being prepared. The amount of (+)-10-camphosulfonic acid added as a SiN polishing inhibitor was set to 0.05 mass% relative to the polishing composition being prepared. The amount of hydrogen peroxide added as an oxidizing agent was set to 0.12 mass% relative to the polishing composition being prepared. Here, a hydrogen peroxide aqueous solution with a concentration of 31 mass% was used for the addition of hydrogen peroxide. The amount of the hydrogen peroxide aqueous solution was added such that the amount of hydrogen peroxide contained therein equals the above amount. The amount of nitric acid added as a pH adjuster was set such that the pH of the polishing composition being prepared becomes 3.0. Here, the pH of polishing composition 1 (liquid temperature: 25°C) was measured by a pH meter (manufactured by Horiba Seisakusho Co., Ltd., Model No.: LAQUA (registered trademark)).

[0181] In addition, the electrical conductivity (EC) of the polishing composition 1 prepared above was measured. The electrical conductivity of the polishing composition 1 (liquid temperature: 25°C) was measured using a benchtop electrical conductivity meter (model number: DS-71 manufactured by Horiba Seisakusho Co., Ltd.). The electrical conductivity (EC) of the polishing composition 1 was 0.69 mS / cm.

[0182] In addition, the zeta potential of the abrasive grains in the polishing composition 1 prepared above was measured. First, the polishing composition was provided to the ELS-Z2 manufactured by Otsuka Denshi Co., Ltd., and measurements were performed by the laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C. Then, the zeta potential (mV) of the abrasive grains in the polishing composition was calculated by interpreting the obtained data using Smoluchowski's equation. The zeta potential of the abrasive grains in the polishing composition 1 was 40 mV.

[0183] (Abrasive compositions 2 to 12)

[0184] Each polishing composition was prepared by operating in the same manner as polishing composition 1, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 1 below. Here, in the preparation of each polishing composition, the amount of pH adjusting agent added is an amount such that the pH of the polishing composition being prepared becomes the value shown in Table 1 below. In addition, pH, electrical conductivity, and the zeta potential of the abrasive particles were each measured in the same manner as polishing composition 1.

[0185] (Abrasive compositions 13 and 14)

[0186] Each polishing composition was prepared by operating in the same manner as polishing composition 1, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 1 below. Here, as the abrasive particles, colloidal silica B (average primary particle size 13.8 nm; average secondary particle size 33 nm; silanol group density 2.2 / nm), which is colloidal silica with sulfonate groups immobilized on the surface, was used. 2 ; (2.39) was used. In addition, pH, electrical conductivity, and zeta potential of the abrasive particles were each measured in the same manner as in polishing composition 1.

[0187] <Grinding Method 1>

[0188] (Grinding device and grinding conditions)

[0189] 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 having a TiN film (titanium nitride film) with a thickness of 2500 Å formed on the substrate surface and a SiN blanket wafer having a SiN film (silicon nitride film) with a thickness of 2000 Å formed on the substrate surface were used:

[0190] [Grinding Device and Grinding Conditions]

[0191] Grinding device: EJ-380IN-CH (Manufactured by Nihon Engisu Co., Ltd.)

[0192] Polishing pad: IC1000 (Made by Nitta-Haas Co., Ltd. (currently Nitta-DuPont Co., Ltd.)

[0193] Grinding pressure (machining pressure): 3.43 psi (also, 1 psi = 6894.76 Pa)

[0194] Rotation speed of grinding plate: 60 rpm (also, 60 rpm = 1 s -1 am)

[0195] Supply rate of abrasive composition: 100 mL / min

[0196] Polishing time: 60 sec

[0197] Conditioner (In-situ dressing missing): Diamond Dresser (SDT-100, manufactured by Noritake Company, Inc.).

[0198] <Evaluation 1>

[0199] (Measurement of grinding speed)

[0200] Each polishing target object 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 meter based on 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 Filmetrics Co., Ltd.: model number Filmetrics F50), by the polishing time (min). Also, 1Å = 0.1nm. The evaluation results are shown in Table 2 below.

[0201]

[0202]

[0203] From the results of Table 1 and Table 2 above, it was confirmed that polishing compositions 1 to 3, 11, and 12 according to the examples, which include cation-modified silica particles and the SiN polishing inhibitor of the present invention, can significantly inhibit the polishing of SiN films. In addition, it was 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 polishing compositions 1 to 3, 11, and 12 according to the examples are particularly suitable for polishing objects that further include titanium nitride in addition to silicon nitride.

[0204] Meanwhile, polishing compositions 4 to 6 and 8 according to comparative examples that do not contain a SiN polishing inhibitor, polishing compositions 7, 9, and 10 according to comparative examples that contain a comparative compound having a structure different from the SiN polishing inhibitor of the present invention, polishing composition 14 according to comparative examples that contains anionic modified silica particles rather than cation-modified silica particles, and polishing composition 13 according to comparative examples that contains anionic modified silica particles rather than cation-modified silica particles and also does not contain a SiN polishing inhibitor, were found to have a reduced polishing inhibitory effect on the SiN film compared to polishing compositions 1 to 3, 11, and 12 according to the examples. As a result, it was also found that the selectivity ratio of the TiN film to the SiN film was lower.

[0205] <Preparation of Abrasive Composition 2>

[0206] (Abrasive composition 15)

[0207] Colloidal silica C, which is colloidal silica with amino groups immobilized as abrasive particles on the surface, in pure water as a dispersion medium (average primary particle size 23 nm; average secondary particle size 50 nm; silanol group density 3.6 / nm 2 A polishing composition 15 was prepared by adding (+)-10-camphosulfonic acid as a SiN polishing inhibitor, 4-acetylmorpholine as a silicon oxide polishing inhibitor, and hydrogen peroxide as an oxidizing agent.

[0208] Here, the amount of colloidal silica C added as abrasive particles was set to 1.8 mass% relative to the polishing composition being prepared. The amount of (+)-10-camphosulfonic acid added as a SiN polishing inhibitor was set to an amount such that the pH of the polishing composition being prepared becomes 3.0. The amount of 4-acetylmorpholine added as a silicon oxide polishing inhibitor was set to 0.13 mass% relative to the polishing composition being prepared. The amount of hydrogen peroxide added as an oxidizing agent was set to 0.09 mass% relative to the polishing composition being prepared. Here, for the addition of hydrogen peroxide, an aqueous hydrogen peroxide solution with a concentration of 31 mass% was used. An amount of the said aqueous hydrogen peroxide solution was added such that the amount of hydrogen peroxide contained therein equals the above amount. Here, the pH of the polishing composition 15 (liquid temperature: 25℃) was measured by a pH meter (manufactured by Horiba Seisakusho Co., Ltd., model number: LAQUA (registered trademark)).

[0209] In addition, 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 (model number: DS-71 manufactured by Horiba Seisakusho Co., Ltd.). The electrical conductivity (EC) of the polishing composition 15 was 0.6 mS / cm.

[0210] In addition, the zeta potential of the abrasive grains in the polishing composition 15 prepared above was measured. First, the polishing composition was provided to the ELS-Z2 manufactured by Otsuka Denshi Co., Ltd., and measurements were performed by the laser Doppler method (electrophoretic light scattering measurement method) using a flow cell at a measurement temperature of 25°C. Then, the zeta potential (mV) of the abrasive grains in the polishing composition was calculated by interpreting the obtained data using Smoluchowski's equation. The zeta potential of the abrasive grains in the polishing composition 15 was 21 mV.

[0211] (Abrasive compositions 16 to 18)

[0212] Each polishing composition was prepared by operating in the same manner as polishing composition 15, except that the type and amount (concentration) of each component and the pH of the polishing composition were changed as shown in Table 3 below. Here, in the preparation of each polishing composition, the amount of (+)-10-camphosulfonic acid added as a SiN polishing inhibitor was such that the pH of the polishing composition prepared became the value shown in Table 3 below. In addition, pH, electrical conductivity, and zeta potential of the abrasive grains were each measured in the same manner as polishing composition 15.

[0213] (Abrasive composition 19)

[0214] Polishing composition 19 was prepared by operating in the same manner as polishing composition 15, except that (+)-10-camphosulfonic acid was not added as a SiN polishing inhibitor, and nitric acid was added as a pH adjuster in an amount such that the pH of the polishing composition being prepared became 3.0. In addition, pH, electrical conductivity, and the zeta potential of the abrasive particles were each measured in the same manner as polishing composition 15.

[0215] <Grinding Method 2>

[0216] (Grinding device and grinding conditions)

[0217] 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 having a TiN film (titanium nitride film) with a thickness of 2,500 Å formed on a substrate surface, a SiN blanket wafer having a SiN film (silicon nitride film) with a thickness of 2,000 Å formed on a substrate surface, and a TEOS-SiO2 blanket wafer having a TEOS-SiO2 film with a thickness of 10,000 Å formed on a substrate surface were used. In addition, the size of these blanket wafers was 300 mm in diameter (12 inch size):

[0218] [Grinding Device and Grinding Conditions]

[0219] Grinding device: Single-sided grinding device FREX300E (manufactured by Ebara Seisakusho, Kabushiki Kaisha)

[0220] Polishing pad: IC1000 (Made by Nitta Haas Co., Ltd. (currently Nitta DuPont Co., Ltd.))

[0221] Grinding pressure (machining pressure): 4.0 psi (also, 1 psi = 6894.76 Pa)

[0222] Rotation speed of grinding plate: 110 rpm (also, 60 rpm = 1 s -1 am)

[0223] Supply rate of abrasive composition: 250 mL / min

[0224] Polishing time: 60 sec

[0225] Conditioner (In-situ dressing missing): Diamond Dresser (SDT-100, manufactured by Noritake Company, Inc.).

[0226] <Evaluation 2>

[0227] (Measurement of grinding speed)

[0228] Each polishing target of the above was polished using each polishing composition, 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 determined by dividing the difference in thickness (Å) of the TiN blanket wafer before and after polishing, measured using a sheet resistance meter based on 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 Filmetrics Co., Ltd.: model number Filmetrics F50), by the polishing time (min). The polishing rate of the TEOS-SiO2 film (TEOS-SiO2 polishing rate) was determined by dividing the difference in thickness (Å) of the TEOS blanket wafer before and after polishing, measured using an optical coherence film thickness measuring device (KLA Tenko: ASET-f5x), by the polishing time (min). Also, 1Å = 0.1nm. The evaluation results are shown in Table 4 below.

[0229] (Stability of abrasive composition)

[0230] For the polishing compositions 15 to 19 prepared above, the presence or absence of abrasive sedimentation was visually checked immediately after preparation (after 10 minutes from preparation). In addition, the compositions were placed in a 25°C constant temperature storage cabinet, and the presence or absence of abrasive sedimentation was visually checked after 3 months. The evaluation results are shown in Table 4 below.

[0231]

[0232]

[0233] From the results of Tables 3 and 4 above, it was confirmed that polishing compositions 15 to 18 according to the examples, comprising cation-modified silica particles and the SiN polishing inhibitor of the present invention, can significantly inhibit the polishing of SiN films. In addition, it was 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 polishing compositions 15 to 18 according to the examples are particularly suitable for polishing objects that further include titanium nitride in addition to silicon nitride. In addition, it was confirmed that these polishing compositions have excellent stability.

[0234] In addition, it was confirmed that polishing compositions 15 to 17 according to the examples, comprising cationic modified silica particles, the SiN polishing inhibitor of the present invention, and the silicon oxide polishing inhibitor of the present invention, can significantly inhibit the polishing of the SiN film and also significantly inhibit the polishing of the silicon oxide film. In addition, it was confirmed that while maintaining a high polishing rate of the TiN film, the selectivity ratio of the TiN film to the silicon oxide film can also be significantly increased in addition to the selectivity ratio of the TiN film to the SiN film. From these results, it can be seen that polishing compositions 15 to 17 according to the examples are particularly suitable for polishing objects that further include titanium nitride in addition to silicon oxide. In addition, it can be seen that polishing compositions 15 to 17 according to the examples are particularly suitable for polishing objects that further include silicon oxide and titanium nitride in addition to silicon nitride.

[0235] Meanwhile, it was confirmed that the polishing composition 19 of the comparative example, which does not contain a SiN polishing inhibitor, has a reduced polishing inhibitory effect on the SiN film compared to the polishing compositions 15 to 18 of the examples. As a result, it was also confirmed that the selectivity ratio of the TiN film to the SiN film is lower.

[0236] This application is based on Japanese Patent Application No. 2020-54516 filed on March 25, 2020 and Japanese Patent Application No. 2020-198712 filed on November 30, 2020, the entire contents of which are incorporated herein by reference.

Claims

Claim 1 The apparatus comprises cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water, wherein the non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1: 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 alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; and R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and In the case where at least one of the above R8 is a substituted group, the substituent is each independently a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 comprises an organic acid group or a salt thereof, and in the above General Formula 1, at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof, and the organic acid group or a salt thereof is a sulfonate group At least one selected from the group consisting of salt groups of the sulfonate group, or in the above General Formula 1, wherein Z1 is O, Z2 is O, Z3 is O, or Z4 is O, and the concentration of a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is,A polishing composition having 0.1 mass% or more and 10 mass% or less based on the total mass of the polishing composition. Claim 2 A polishing composition comprising cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, a compound represented by the following general formula 2, and water, wherein the non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1: 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 alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; and R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and Where at least one of the above R8 is a substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 comprises an organic acid group or a salt thereof; In the above general formula 2, X1 is CR 11 R 11 or C=O and X2 is, CR 12 R 12 or C=O and X3 is, CR 13 R 13 or C=O and X4 is, CR 14 R 14 or C=O and,R 10 Silver, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3, and 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, and * is a bonding hand bonded to the cyclic nitrogen atom (N) of General Formula 2 above, and R 10 In the case of this substituted group, the substituent is, respectively, a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group, and R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 'is, each independently, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, and R 11 , above R 11 ', above R 12 , above R 12 ', above R 13 , above R 13 ', above R 14 , above R 14 ' and the above R 15 In the case where at least one of the groups is substituted, the substituents are, respectively, a deuterium atom, a halogen atom, an unsubstituted oxy hydrocarbon group, or an unsubstituted polyoxyalkylene group. Claim 3 A polishing composition according to claim 1 or 2, wherein in the above general formula 1, at least one of Z1, Z2, Z3 and Z4 is C=O. Claim 4 A polishing composition according to claim 1 or 2, wherein in the above general formula 1, at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and R8 is an organic acid group or a salt group thereof, or an alkyl group substituted with an organic acid group or a salt group thereof. Claim 5 A polishing composition according to claim 1 or 2, wherein the organic acid group or the salt group thereof is at least one selected from the group consisting of a carboxyl group, a salt group of a carboxyl group, a sulfonate group, a salt group of a sulfonate group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group. Claim 6 A polishing composition according to claim 1, wherein the compound represented by the above general formula 1 comprises at least one selected from the group consisting of (+)-10-camphosulfonic acid and campanic acid. Claim 7 A polishing composition according to claim 2, wherein the compound represented by the above general formula 1 comprises at least one selected from the group consisting of (+)-10-camphosulfonic acid, campanic acid, and ketopynic acid. Claim 8 A polishing composition according to claim 1 or 2, wherein the zeta potential of the cation-modified silica particles is a positive value. Claim 9 A polishing composition according to claim 1 or 6, further comprising a compound represented by the following general formula 2: In the above general formula 2, X1 is CR 11 R 11 or C=O and X2 is, CR 12 R 12 or C=O and X3 is, CR 13 R 13 or C=O and X4 is, CR 14 R 14 or C=O and,R 10 Silver, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3, and 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, and * is a bonding hand bonded to the cyclic nitrogen atom (N) of General Formula 2 above, and R 10 In the case of this substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group, and R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 'is, each independently, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, or a substituted or unsubstituted polyoxyalkylene group, and R 11 , above R 11 ', above R 12 , above R 12 ', above R 13 , above R 13 ', above R 14 , above R 14 ' and the above R 15 In the case where at least one of the groups is substituted, the substituents are, respectively, a deuterium atom, a halogen atom, an unsubstituted oxy hydrocarbon group, or an unsubstituted polyoxyalkylene group. Claim 10 A polishing composition according to claim 1 or 2, further comprising an oxidizing agent. Claim 11 A polishing composition according to claim 1 or 2, wherein the pH is less than 7. Claim 12 A polishing composition according to claim 1 or 2, wherein the electrical conductivity is 30 μS / cm or more and 2 mS / cm or less. Claim 13 A polishing composition used to polish a workpiece containing silicon nitride, in accordance with claim 1 or 2. Claim 14 A polishing composition used to polish a workpiece, further comprising titanium nitride in Clause 13. Claim 15 A polishing composition used to polish a workpiece, further comprising silicon dioxide in Clause 13. Claim 16 The method comprises mixing cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, and water, wherein the non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1: 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 alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; and R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and In the case where at least one of the above R8 is a substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 comprises an organic acid group or a salt thereof, and in the above General Formula 1, at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof, and the organic acid group or a salt thereof is a sulfo group and The concentration of a non-aromatic cross-linked cyclic compound having an organic acid group or its salt group, which is at least one selected from the group consisting of salt groups of a sulfonate group, or in the above general formula 1, wherein Z1 is O, Z2 is O, Z3 is O, or Z4 is O, is, said organic acid group or its salt group, is,A method for manufacturing a polishing composition, wherein the composition comprises 0.1 mass% or more and 10 mass% or less based on the total mass of the polishing composition. Claim 17 A method for preparing a polishing composition according to claim 16, wherein the compound represented by the above general formula 1 comprises at least one selected from the group consisting of (+)-10-camphosulfonic acid and campanic acid. Claim 18 A method for preparing a polishing composition comprising mixing cationic modified silica particles, a non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof, a compound represented by the following general formula 2, and water, wherein the non-aromatic cross-linked cyclic compound having an organic acid group or a salt group thereof is a compound represented by the following general formula 1: 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 alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; and R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7 and Where at least one of the above R8 is a substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof, and at least one of the above R1, the above R1', the above R2, the above R2', the above R3, the above R3', the above R4, the above R4', the above R5, the above R6, the above R7 and the above R8 comprises an organic acid group or a salt thereof; In the above general formula 2, X1 is CR 11 R 11 or C=O and X2 is, CR 12 R 12 or C=O and X3 is, CR 13 R 13 or C=O and X4 is, CR 14 R 14 or C=O and,R 10 Silver, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3, and 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, and * is a bonding hand bonded to the cyclic nitrogen atom (N) of General Formula 2 above, and R 10 In the case of this substituted group, the substituent is, respectively, a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group, and R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 'is, each independently, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, and R 11 , above R 11 ', above R 12 , above R 12 ', above R 13 , above R 13 ', above R 14 , above R 14 ' and the above R 15 In the case where at least one of the groups is substituted, the substituents are, respectively, a deuterium atom, a halogen atom, an unsubstituted oxy hydrocarbon group, or an unsubstituted polyoxyalkylene group. Claim 19 A method for preparing a polishing composition according to claim 18, wherein the compound represented by the above general formula 1 comprises at least one selected from the group consisting of (+)-10-camphosulfonic acid, campanic acid, and ketopynic acid. Claim 20 A method for preparing a polishing composition according to claim 16 or 17, comprising further mixing a compound represented by the following general formula 2: In the above general formula 2, X1 is CR 11 R 11 or C=O and X2 is, CR 12 R 12 or C=O and X3 is, CR 13 R 13 or C=O and X4 is, CR 14 R 14 or C=O and,R 10 Silver, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, a substituted or unsubstituted polyoxyalkylene group, or a group represented by the following general formula 3, and 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, and * is a bonding hand bonded to the cyclic nitrogen atom (N) of General Formula 2 above, and R 10 In the case of this substituted group, the substituent is, each independently, a deuterium atom, a halogen atom, an unsubstituted oxyhydrocarbon group, or an unsubstituted polyoxyalkylene group, and R 11 , R 11 ', R 12 , R 12 ', R 13 , R 13 ', R 14 and R 14 'is, each independently, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, a substituted or unsubstituted oxy hydrocarbon group, or a substituted or unsubstituted polyoxyalkylene group, and R 11 , above R 11 ', above R 12 , above R 12 ', above R 13 , above R 13 ', above R 14 , above R 14 ' and the above R 15 In the case where at least one of the groups is substituted, the substituents are, respectively, a deuterium atom, a halogen atom, an unsubstituted oxy hydrocarbon group, or an unsubstituted polyoxyalkylene group. Claim 21 A polishing method for polishing an object to be polished using a polishing composition described in paragraph 1 or 2. Claim 22 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 described in claim 21.

Images