Polishing composition, polishing method, and method for manufacturing semiconductor substrate

Abstract

To provide means capable of polishing an organic material at a high polishing speed and improving a ratio of the polishing speed for the organic material to a polishing speed for the material having a metal-nitrogen bond.SOLUTION: A polishing composition according to the present invention contains zirconia particles, a selectivity improver for improving a ratio of a polishing speed for an organic material (b) to a polishing speed for a material (a) having a metal-nitrogen bond, and a dispersing medium, wherein in a particle size distribution of the zirconia particles obtained by a laser diffraction / scattering method, a diameter (D50) of the particles when a cumulative volume of the particles from a fine particle side reaches 50% of a total volume of the particles is 5 nm or more and 150 nm or less, and a pH of the polishing composition is less than 7.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As semiconductor devices become more highly integrated, the formation of finer patterns and multilayer circuits is required. To achieve this, films made of various materials with different etching selectivity characteristics are needed. Among these various materials, organic films have better etching selectivity characteristics than other silicon-containing films and can be used as mask films or sacrificial films. In particular, in semiconductor manufacturing processes, it is necessary to remove the organic films by performing a chemical mechanical polishing (CMP) process for planarization.

[0003] As a technique for polishing such organic films, for example, Patent Document 1 discloses an abrasive containing silica-containing abrasive grains, an allylamine-based polymer, and water, in which the mass ratio of the allylamine-based polymer content to the abrasive grain content is 0.002 to 0.400, and the abrasive grains have a positive charge in the abrasive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-189784 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 still has a problem in that the removal rate of organic films (organic materials) is low. In addition, there has been a recent growing demand for a higher removal rate of organic materials relative to the removal rate of materials having a metal-nitrogen bond, but such a demand has not been addressed to date.

[0006] Therefore, an object of the present invention is to provide a means for polishing organic materials at a high polishing rate and for improving the ratio of the polishing rate for organic materials to the polishing rate for materials having a metal-nitrogen bond. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by a polishing composition comprising zirconia particles, a selectivity improver that improves the ratio of the removal rate of an organic material (b) to the removal rate of a material (a) having a metal-nitrogen bond, and a dispersion medium, wherein, in a particle size distribution determined by a laser diffraction scattering method for the zirconia particles, the particle diameter (D50) at which the cumulative particle volume from the fine particle side reaches 50% of the total particle volume is 5 nm or more and 150 nm or less, and the pH is less than 7, thereby completing the present invention. [Effects of the Invention]

[0008] According to the present invention, it is possible to polish organic materials at a high polishing rate, and a means is provided for improving the ratio of the polishing rate of organic materials to the polishing rate of materials having a metal-nitrogen bond. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention provides a polishing composition comprising zirconia particles, a selectivity improver that improves the ratio of the removal rate of organic material (b) to the removal rate of material (a) having a metal-nitrogen bond, and a dispersion medium, wherein, in the particle size distribution of the zirconia particles determined by a laser diffraction scattering method, the particle diameter (D50) at which the cumulative particle volume from the fine particle side reaches 50% of the total particle volume is 5 nm or more and 150 nm or less, and the pH is less than 7. The polishing composition according to one embodiment of the present invention having such a configuration is capable of polishing organic material (b) at a high removal rate and can improve the ratio of the removal rate of organic material (b) to the removal rate of material (a) having a metal-nitrogen bond.

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0011] Unless otherwise specified, in this specification, operations and measurements of physical properties are performed at room temperature (20°C or higher and 25°C or lower) and a relative humidity of 40% RH or higher and 50% RH or lower. In this specification, the ratio of the polishing rate of the organic material (b) to the polishing rate of the material (a) having a metal-nitrogen bond is also simply referred to as the "selectivity."

[0012] [Polished object] The object to be polished according to the present invention preferably contains a material (a) having a metal-nitrogen bond and an organic material (b).

[0013] Examples of the material (a) having a metal-nitrogen bond (hereinafter also simply referred to as "material (a)") include silicon nitride (SiN), tantalum nitride (TaN), and titanium nitride (TiN).

[0014] The organic material (b) (hereinafter also simply referred to as "material (b)") is not particularly limited, but examples thereof include amorphous carbon, spin-on carbon (SOC), diamond-like carbon (DLC), nanocrystalline diamond, graphene, etc. Among these, amorphous carbon, spin-on carbon, and diamond-like carbon are preferred.

[0015] The film containing material (a) and the film containing material (b) can be formed by CVD, PVD, spin coating, or the like.

[0016] The object to be polished according to the present invention may further contain other materials in addition to materials (a) and (b), such as silicon oxide, single-crystal silicon, polycrystalline silicon (polysilicon), amorphous silicon, polycrystalline silicon doped with n-type or p-type impurities, amorphous silicon doped with n-type or p-type impurities, elemental metals, and SiGe.

[0017] Examples of polishing objects containing silicon oxide include TEOS (Tetraethyl Orthosilicate) type silicon oxide surfaces (hereinafter also referred to as "TEOS" or "TEOS film") produced using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma) films, USG (Undoped Silicate Glass) films, PSG (Phosphorus Silicate Glass) films, BPSG (Boron-Phospho Silicate Glass) films, and RTO (Rapid Thermal Oxidation) films.

[0018] Examples of elemental metals include tungsten, copper, cobalt, hafnium, nickel, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium.

[0019] [Zirconia particles] The polishing composition of the present invention contains zirconia particles as abrasive grains. The zirconia particles have the function of mechanically polishing an object to be polished. The zirconia particles may be used alone or in combination of two or more types. Furthermore, the zirconia particles may be commercially available or may be synthetic.

[0020] The zirconia particles are preferably colloidal zirconia particles or pulverized / calcined zirconia particles, and more preferably colloidal zirconia particles. The zirconia particles may be undoped or may be doped, for example, with yttrium (Y) or its oxide. The pulverized / calcined zirconia particles are produced by calcining in a calcination furnace followed by a pulverization process. More specifically, the calcination target is heated from room temperature (e.g., 20-25°C) over a period of, for example, 1-10 hours, 1.2-5 hours, or typically about 2 hours. The heating rate is, for example, 100-1000°C / hour or 200-800°C / hour. The calcination temperature is then set to about 1300-1500°C and maintained within that temperature range for, for example, 1-3 hours, typically about 2 hours. The calcination temperature is then naturally cooled to room temperature. The time from when the temperature of the firing object starts to be increased until it is naturally cooled back to room temperature is, for example, 3 to 20 hours, typically 7 to 8 hours.

[0021] Zirconia particles doped with yttrium or its oxide (hereinafter also referred to simply as "Y-stabilized zirconia particles") are preferably prepared by mixing zirconia powder and yttrium powder in a ratio that results in a predetermined yttrium doping amount before the calcination when calcined / pulverized zirconia is used as the raw material, and then calcining the mixture as described above. When colloidal zirconia is used as the raw material, the doped zirconia particles are generally prepared by pre-reacting the required number of moles of yttrium and zirconium precursors and then granulating them. Regarding the doping method, the contents of, for example, JP 2010-523451 A and U.S. Pat. No. 3,110,681 can be referenced as appropriate.

[0022] The concentration (mol %) of yttrium in the Y-stabilized zirconia particles is defined as follows:

[0023]

number

[0024] The molar percentage of yttrium can be determined by X-ray fluorescence (XRF) or any other method known in the art. The concentration of yttrium in the Y-stabilized zirconia particles is at least 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, 11 mol%, 12 mol%, 13 mol%, 14 mol%, or 15 mol%. The concentration of yttrium in the Y-stabilized zirconia particles is less than 45 mol%, 40 mol%, 35 mol%, 30 mol%, 25 mol%, or 20 mol%. The concentration of yttrium in the Y-stabilized zirconia particles is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mol%, or any range therebetween.

[0025] The concentration of yttrium in the Y-stabilized zirconia particles is 1 mol% or more, 2 mol% or more, 3 mol% or more, 4 mol% or more, 5 mol% or more, 6 mol% or more, 7 mol% or more, 8 mol% or more, 9 mol% or more, 10 mol% or more, 11 mol% or more, 12 mol% or more, 13 mol% or more, 14 mol% or more, 15 mol% or more, 16 mol% or more, 17 mol% or more, 18 mol% or more, 19 mol% or more, 20 mol% or more, 21 mol% or more, 22 mol% or more, 23 mol% or more, 24 mol% or more, or 25 mol% or more. In some embodiments, the Y-stabilized zirconia particles comprise a tetragonal phase (e.g., the yttrium in the Y-stabilized zirconia particles is at a concentration sufficient to provide a tetragonal phase). In some embodiments, the Y-stabilized zirconia particles comprise a cubic phase (e.g., the yttrium in the Y-stabilized zirconia particles is at a concentration sufficient to provide a cubic phase). In some embodiments, the concentration of yttrium in the Y-stabilized zirconia particles is greater than 2.6 mol%, greater than 3.3 mol%, greater than 9.3 mol%, or greater than 10.6 mol%. Note that the expression "greater than or equal to X (X is a numerical value)" used herein means that the value may be greater than or equal to X or may be less than or equal to X. In other words, when making a correction, the numerical value X can be the basis for both a lower limit and an upper limit.

[0026] Zirconia particles (e.g., colloidal zirconia, ground / calcined zirconia, or doped zirconia) are aggregates containing primary particles and / or secondary particles. Aggregates can be formed from a combination of individual particles, which are known in the art as primary particles, while aggregated combinations of particles are known in the art as secondary particles. The zirconia particles in the polishing composition can be in the form of primary particles or in the form of secondary particles, which are aggregates of primary particles. Alternatively, the zirconia particles can exist in both the form of primary particles and the form of secondary particles. In a preferred embodiment, the zirconia particles in the polishing composition are at least partially present in the form of secondary particles.

[0027] The zirconia particles according to the present invention have a particle diameter (D50, hereinafter simply referred to as "D50") of 5 nm or more and 150 nm or less when the cumulative particle volume from the fine particle side reaches 50% of the total particle volume in the particle size distribution determined by a laser diffraction scattering method. If the D50 of the zirconia particles is less than 5 nm, the polishing rate will be significantly reduced. On the other hand, if the D50 of the zirconia particles exceeds 150 nm, scratches may occur on the polished surface. The D50 of the zirconia particles is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 50 nm or more. Furthermore, the D50 of the zirconia particles is preferably 300 nm or less, more preferably 150 nm or less, and even more preferably 90 nm or less. That is, the D50 of the zirconia particles is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 150 nm or less, and even more preferably 50 nm or more and 90 nm or less. More specifically, the D50 of the zirconia particles can be measured by the method described in the Examples.

[0028] The shape of the zirconia particles is not particularly limited and may be spherical or non-spherical. Specific examples of non-spherical shapes include polygonal prisms such as triangular prisms and quadrangular prisms, cylinders, bale-shaped cylinders in which the center is bulged more than the ends, doughnut-shaped discs with a central hole, plate-shaped zirconia particles, cocoon-shaped zirconia particles with a central constriction, associative spheres in which multiple particles are integrated, confetti-shaped zirconia particles with multiple protrusions on the surface, rod-shaped zirconia particles, diamond-shaped zirconia particles, square zirconia particles, and rugby ball-shaped zirconia particles, and are not particularly limited thereto.

[0029] The lower limit of the zeta potential of zirconia particles in the polishing composition is not particularly limited, but is preferably 10 mV or more, more preferably 20 mV or more, even more preferably 25 mV or more, and particularly preferably 30 mV or more.The upper limit of the zeta potential of zirconia particles in the polishing composition is not particularly limited, but is preferably 70 mV or less, more preferably 65 mV or less, even more preferably 55 mV or less, and particularly preferably 50 mV or less.That is, the zeta potential of abrasive grains in the polishing composition is preferably 10 mV or more and 70 mV or less, more preferably 20 mV or more and 65 mV or less, even more preferably 25 mV or more and 55 mV or less, and particularly preferably 30 mV or more and 50 mV or less.

[0030] Zirconia particles having the above-mentioned zeta potential can polish the organic material (b) at a higher polishing rate.

[0031] In this specification, the zeta potential of the zirconia particles is a value measured by the method described in Examples. The zeta potential of the zirconia particles can be adjusted by the pH of the polishing composition, etc.

[0032] The content (concentration) of zirconia particles in the polishing composition is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.08% by mass or more, and particularly preferably more than 0.1% by mass, based on the total mass of the polishing composition. The upper limit of the content of zirconia particles in the polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 4% by mass or less, even more preferably 1% by mass or less, and particularly preferably less than 1% by mass, based on the total mass of the polishing composition. That is, the content of zirconia particles is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, even more preferably 0.08% by mass or more and 4% by mass or less, even more preferably 0.08% by mass or more and 1% by mass or less, and particularly preferably more than 0.1% by mass or less and less than 1% by mass, based on the total mass of the polishing composition.

[0033] When the content of the zirconia particles is within this range, the organic material (b) can be polished at a higher polishing rate. When the polishing composition contains two or more types of zirconia particles, the content of the zirconia particles refers to the total amount of these zirconia particles.

[0034] The polishing composition of the present invention may further contain abrasive particles other than zirconia particles, provided that the effects of the present invention are not impaired. Such other abrasive particles may be inorganic particles, organic particles, or organic-inorganic composite particles. Specific examples of inorganic particles include unmodified silica, cation-modified silica, particles made of metal oxides such as alumina, ceria, and titania, silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles. The other abrasive particles may be used alone or in combination of two or more types. Furthermore, the other abrasive particles may be commercially available products or synthetic products.

[0035] However, the content of the other abrasive grains is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the abrasive grains. Most preferably, the content of the other abrasive grains is 0% by mass, i.e., the abrasive grains are composed only of zirconia particles.

[0036] [Selectivity enhancer] The polishing composition of the present invention contains a selectivity enhancer, which can improve the ratio (selectivity) of the removal rate of material (b) to the removal rate of material (a).

[0037] The selectivity enhancer according to the present invention is not particularly limited, but examples thereof include (1) water-soluble polymers having polar groups, (2) non-aromatic bridged cyclic compounds having organic acid groups or their salt groups, and (3) anionic surfactants. It is believed that these compounds (1) to (3) are adsorbed to material (a) primarily by electrostatic attraction. Because the selectivity enhancer has a bulky structure, it suppresses collisions between zirconia particles and material (a) and strongly protects material (a) from the zirconia particles. This weakens the scraping action of the zirconia particles against material (a). Furthermore, because the zirconia particles and material (a) also have positive charges, electrostatic repulsion occurs between them, weakening the scraping action and frequency of the zirconia particles against material (a). Furthermore, the combination of zirconia particles and a selectivity enhancer synergistically improves the functions of both, dramatically improving the polishing suppression effect of the zirconia particles against material (a), and improving the selectivity.

[0038] The above mechanism is merely a presumption, and the present invention is not limited to the above mechanism.

[0039] The selectivity improver according to the present invention will be described in detail below. The selectivity improver may be used alone or in combination of two or more. Furthermore, the selectivity improver may be a commercially available product or a synthetic product.

[0040] [(1) Water-soluble polymer having a polar group] In the present invention, the selectivity improver preferably contains a water-soluble polymer having a polar group. Examples of the polar group include a hydroxy group, a carboxy group, an acid anhydride group, a sulfonic acid group, a phosphate group, an amide group, a cyano group, a morpholino group, and a quaternary ammonium group. The polar group possessed by the water-soluble polymer may be one type alone or a combination of two or more types. In this specification, "water-soluble" means that the solubility in water (25°C) is 1 g / 100 mL or more, and "polymer" means a (co)polymer having a weight-average molecular weight of 1,000 or more.

[0041] Specific examples of water-soluble polymers having a polar group include homopolymers such as polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylamide, polyvinylacetamide, and poly(meth)acryloylmorpholine; copolymers such as vinylpyrrolidone-vinyl alcohol copolymer, vinylpyrrolidone-(meth)acrylamide copolymer, vinylpyrrolidone-vinylacetamide copolymer, and vinylpyrrolidone-(meth)acryloylmorpholine copolymer; etc. The copolymer may be in the form of a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer.

[0042] Alternatively, functionally modified water-soluble polymers can be used, which are polyvinyl alcohol, polyvinylpyrrolidone, or poly(meth)acrylamide, to which functional groups such as sulfonic acid groups, carboxylic acid groups, and quaternary ammonium groups have been further introduced. Such functionally modified water-soluble polymers can be synthesized by conventionally known methods.

[0043] The water-soluble polymer having a polar group may be used alone or in combination of two or more kinds.

[0044] Among these, from the viewpoint of further improving the effects of the present invention, it is preferable to include at least one selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide.

[0045] The lower limit of the weight-average molecular weight (Mw) of the water-soluble polymer having a polar group is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 4,000 or more. The upper limit of the weight-average molecular weight (Mw) of the water-soluble polymer having a polar group is not particularly limited, but is preferably 1,000,000 or less, more preferably 800,000 or less, and even more preferably 600,000 or less. That is, the weight-average molecular weight (Mw) of the water-soluble polymer having a polar group is preferably 1,000 or more and 1,000,000 or less, more preferably 2,000 or more and 800,000 or less, and even more preferably 4,000 or more and 600,000 or less.

[0046] In this specification, the weight-average molecular weight (Mw) of the water-soluble polymer having a polar group is a polyethylene glycol-equivalent value determined by gel permeation chromatography (GPC). More specifically, it can be measured by the method described in the Examples.

[0047] [(2) Non-aromatic bridged cyclic compound having an organic acid group or a salt thereof] In the present invention, it is preferable to use (2) a non-aromatic bridged cyclic compound having an organic acid group or a salt thereof as the selectivity improving agent.

[0048] In this specification, the non-aromatic bridged cyclic compound refers to a bridged compound that does not have an aromatic ring in the molecule and has a structure in which both ends of the linear structural portion of two or more substituents of one single ring structure are bonded, excluding a structure in which one side is shared (i.e., a fused ring compound).The non-aromatic bridged cyclic compound is not particularly limited, and examples thereof include camphor, adamantane, and derivatives in which the hydrocarbon group forming the ring in these molecular structures is substituted with other atoms or functional groups.

[0049] The organic acid group or its salt group is not particularly limited, but preferred examples include a carboxy group, a carboxy salt group, a sulfo group, a sulfo salt group, a phosphonic acid group, a phosphonic acid salt group, a phosphate group, and a phosphate salt group. That is, the non-aromatic bridged cyclic compound having an organic acid group or its salt group preferably has at least one selected from the group consisting of a carboxy group, a carboxy salt group, a sulfo group, a sulfo salt group, a phosphonic acid group, a phosphonic acid salt group, a phosphate group, and a phosphate salt group. Furthermore, the non-aromatic bridged cyclic compound having an organic acid group or its salt group more preferably has a carboxy group, a carboxy salt group, a sulfo group, or a sulfo salt group, even more preferably a carboxy group or a sulfo group, and particularly preferably a sulfo group. These groups further improve the polishing suppression effect of material (a). Furthermore, when polishing an object further containing material (b) in addition to material (a), the selectivity is further improved.

[0050] The non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is not particularly limited, but from the viewpoint of further improving the polishing suppression effect of material (a) and from the viewpoint of achieving a high polishing rate of material (b), it is preferable to use a compound represented by the following general formula 1:

[0051] [ka]

[0052] In the above general formula 1, Z1 is CR1R1′, C═O or O; Z2 is CR2R2', C=O or O; Z3 is CR3R3', C=O or O; Z4 is CR4R4', C=O or O; R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted hydrocarbon group (e.g., a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted alkynyl group), a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; When at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted hydrocarbon group (e.g., an unsubstituted alkyl group, an unsubstituted alkenyl group, or an unsubstituted alkynyl group), an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; At least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 includes an organic acid group or a salt group thereof.

[0053] In the above general formula 1, it is preferable that at least one of Z1, Z2, Z3, and Z4 is C=O, it is more preferable that at least one of Z1 and Z3 is C=O, it is further preferable that either one of Z1 and Z3 is C=O, and it is particularly preferable that Z3 is C=O. In this case, the group other than C=O in Z1, Z2, Z3, and Z4 is preferably CRR' (hereinafter, R represents R1 to R4 corresponding to Z1 to Z4, respectively, and R' represents R1' to R4' corresponding to Z1 to Z4, respectively) or O, and it is more preferable that it is CRR'.

[0054] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, the halogen atom is not particularly limited, and examples thereof include F, Cl, Br, and I.

[0055] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, examples of the hydrocarbon group include an alkyl group, an alkenyl group, and an alkynyl group. Among these, an alkyl group is preferred.

[0056] The alkyl group may be linear, branched, or cyclic. The alkyl group is not particularly limited, but examples include alkyl groups having 1 to 12 carbon atoms. Of these, linear or branched alkyl groups having 1 to 5 carbon atoms are preferred, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, and a 2-methylbutyl group. Of these, linear alkyl groups having 1 to 5 carbon atoms are preferred, with a methyl group, an ethyl group, an n-propyl group, or an isopropyl group being more preferred, a methyl group or an ethyl group being even more preferred, and a methyl group being particularly preferred.

[0057] The alkenyl group may be linear, branched, or cyclic. The alkenyl group is not particularly limited, and examples thereof include vinyl, 2-propenyl, 2-butenyl, 3-butenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-2-propenyl, and 1-ethyl-2-propenyl.

[0058] The alkynyl group may be linear, branched, or cyclic. Examples of the alkynyl group include, but are not limited to, 2-butynyl, 3-pentynyl, hexynyl, heptynyl, octynyl, and decynyl.

[0059] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, the alkoxy group is not particularly limited, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a t-pentoxy group, and a 2-methylbutoxy group.

[0060] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, the polyoxyalkylene group is not particularly limited, and examples thereof include a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group, a block polyoxyalkylene group of polyoxyethylene groups and polyoxypropylene groups, a random polyoxyalkylene group of polyoxyethylene groups and polyoxypropylene groups, a block polyoxyalkylene group of polyoxyethylene groups and polyoxybutylene groups, and a random polyoxyalkylene group of polyoxyethylene groups and polyoxybutylene groups.

[0061] In R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, the organic acid group or the salt group is not particularly limited, but as described above, it is preferably at least one selected from the group consisting of a carboxy group, a salt group of a carboxy group, a sulfo group, a salt group of a sulfo group, a phosphonic acid group, a salt group of a phosphonic acid group, a phosphate group, and a salt group of a phosphate group. Among these, a carboxy group, a salt group of a carboxy group, a sulfo group, or a salt group of a sulfo group is more preferred, a carboxy group or a sulfo group is even more preferred, and a sulfo group is particularly preferred.

[0062] In the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is a substituted group, the halogen atoms, hydrocarbon groups (e.g., alkyl groups, alkenyl groups, alkynyl groups), alkoxy groups, polyoxyalkylene groups, organic acid groups, or salt groups thereof as substituents are the same as those described for these groups in R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 in the above general formula 1, respectively.

[0063] In the above general formula 1, when at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is a substituted hydrocarbon group (e.g., a substituted alkyl group, a substituted alkenyl group, a substituted alkynyl group), it is preferable that the substituents are 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. Furthermore, 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.

[0064] In the above general formula 1, it is preferred that at least one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof. Among these, it is more preferred that only one of R1, R1', R2, R2', R3, R3', R4, R4', R5, R6, R7, and R8 is an organic acid group or a salt thereof, or an alkyl group substituted with an organic acid group or a salt thereof. In this case, the organic acid group or its salt group, or the alkyl group substituted with an organic acid group or its salt group, is preferably a carboxy group or its salt group, a sulfo group or its salt group, a methyl group substituted with a carboxy group or its salt group, or a methyl group substituted with a sulfo group or its salt group, more preferably a carboxy group or a methyl group substituted with a sulfo group, and most preferably a methyl group substituted with a sulfo group. These groups further improve the polishing suppression effect of material (a). Furthermore, when polishing an object containing other materials (particularly material (b)) in addition to material (a), the selectivity of material (b) to material (a) is further improved.

[0065] In the above general formula 1, it is particularly preferable that R1, R1', R2, R2', R3, R3', R4, and R4' are each independently a hydrogen atom.

[0066] In the above general formula 1, R5 is preferably a hydrogen atom or a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group, even more preferably a substituted alkyl group, and particularly preferably an alkyl group substituted with an organic acid group or a salt thereof. In this case, the alkyl group substituted with an organic acid group or a salt thereof is preferably a methyl group substituted with a sulfo group or a salt thereof, and particularly preferably a methyl group substituted with a sulfo group.

[0067] In the above general formula 1, R6 is preferably a hydrogen atom, or an organic acid group or a salt thereof, more preferably a hydrogen atom, or a carboxy group or a salt thereof, even more preferably a hydrogen atom or a carboxy group, and particularly preferably a hydrogen atom.

[0068] 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.

[0069] The non-aromatic bridged cyclic compound having an organic acid group or a salt thereof may be used alone or in combination of two or more.

[0070] Preferred examples of the non-aromatic bridged cyclic compound having an organic acid group or a salt thereof include 10-camphorsulfonic acid, camphanic acid, and ketopinic acid. Among these, 10-camphorsulfonic acid or camphanic acid is preferred, and 10-camphorsulfonic acid is more preferred. 10-camphorsulfonic acid may be any one stereoisomer, any mixture of stereoisomers, or a racemate.

[0071] From the viewpoint of further improving the effects of the present invention, it is more preferable that the selectivity improver contains both (1) a water-soluble polymer having a polar group and (2) a non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof.

[0072] [(3) Anionic surfactant] In the present invention, an anionic surfactant (3) can be used as a selectivity enhancer. While the anionic surfactant (3) can be used alone as a selectivity enhancer, it is preferable to use it in combination with the compounds (1) and / or (2) above. Such a combination further enhances the effects of the present invention. The anionic surfactant is a surfactant having an anionic hydrophilic group, and carboxylic acid type, sulfonic acid type, sulfate ester type, phosphate ester type, etc. can be used without particular limitation.

[0073] Carboxylic acid-type anionic surfactants are preferably salts of carboxyl groups having a main chain consisting of a linear or branched hydrocarbon group having 1 to 22 carbon atoms, an acyl group, a polyoxyalkylene group, an aromatic group, or a combination thereof, with a metal such as an alkali metal or a Group 2 metal. The hydrocarbon group may be a linear or branched hydrocarbon group having 1 to 18 carbon atoms, and may be saturated or unsaturated. More specifically, examples of surfactants that can be used include sodium laurate, sodium stearate, sodium laureth-6 carboxylate (sodium polyoxyethylene (4.5) lauryl ether acetate), sodium lauroyl sarcosinate, sodium octanoate, sodium decanoate, sodium myristate, sodium palmitate, sodium coconut oil fatty acid (C8-18) sarcosinate, and potassium coconut oil fatty acid.

[0074] Preferred sulfonic acid-type anionic surfactants are salts of a sulfonyl group having a main chain consisting of a linear or branched hydrocarbon group having 1 to 22 carbon atoms, an acyl group, a polyoxyalkylene group, an aromatic group, or a combination thereof, and a metal such as an alkali metal or a Group 2 metal. The hydrocarbon group may be a linear or branched hydrocarbon group having 1 to 18 carbon atoms, and may be saturated or unsaturated. Specific examples include sodium lauryl sulfoacetate, sodium 1-propanesulfonate, sodium 1-butanesulfonate, sodium 1-pentanesulfonate, sodium 1-hexanesulfonate, sodium 1-heptanesulfonate, sodium 1-octanesulfonate, sodium 1-decanesulfonate, sodium 1-dodecanesulfonate, sodium toluenesulfonate, sodium cumenesulfonate, sodium naphthalenesulfonate, disodium naphthalenedisulfonate, trisodium naphthalenetrisulfonate, sodium alphaolefinsulfonate, and sodium dodecylbenzenesulfonate.

[0075] Preferred sulfate ester-type anionic surfactants are salts of sulfate groups having a main chain consisting of a linear or branched hydrocarbon group having 1 to 22 carbon atoms, an acyl group, a polyoxyalkylene group, an aromatic group, or a combination thereof, and a metal such as an alkali metal or a Group 2 metal. The hydrocarbon group may be a linear or branched hydrocarbon group having 1 to 18 carbon atoms, and may be saturated or unsaturated. Specific examples that can be used include sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate (polyoxyethylene lauryl ether sodium sulfate), sodium cetyl sulfate, sodium cocoglyceryl sulfate (hydrogenated sodium coconut oil fatty acid glyceryl sulfate), triethanolamine lauryl sulfate, ammonium lauryl sulfate, and triethanolamine laureth sulfate.

[0076] The phosphate ester-type anionic surfactant is preferably a salt of a phosphate group having a main chain consisting of a hydrocarbon group having a linear or branched chain and an acyl group, a polyoxyalkylene group, an aromatic group, or a combination thereof, with a metal such as an alkali metal or a Group 2 metal. The hydrocarbon group may be a linear or branched group having a carbon number of 1 to 18, and may be saturated or unsaturated. Specific examples that can be used include sodium lauryl phosphate, sodium polyoxyethylene cetyl ether phosphate (sodium polyoxyethylene (5) cetyl ether phosphate), lauryl phosphate, and potassium lauryl phosphate.

[0077] The anionic surfactants may be used alone or in combination of two or more.

[0078] Among these anionic surfactants, at least one selected from the group consisting of sodium 1-propanesulfonate, sodium 1-butanesulfonate, sodium 1-pentanesulfonate, sodium 1-hexanesulfonate, sodium 1-heptanesulfonate, sodium 1-octanesulfonate, and ammonium lauryl sulfate is more preferred, and at least one selected from the group consisting of sodium 1-pentanesulfonate, sodium 1-hexanesulfonate, sodium 1-heptanesulfonate, and sodium 1-octanesulfonate is even more preferred.

[0079] The weight average molecular weight of these anionic surfactants is less than 1,000, preferably 500 or less, more preferably 250 or less, and even more preferably 200 or less.

[0080] The content (concentration) of the selectivity enhancer is not particularly limited and can be appropriately selected depending on the type of selectivity enhancer. For example, when (1) a water-soluble polymer having a polar group is used as the selectivity enhancer, the content is preferably 0.00001% by mass or more, more preferably 0.00005% by mass or more, and even more preferably 0.0001% by mass or more, relative to the total mass of the polishing composition. Within this range, the polishing suppression effect of material (a) is further improved. Furthermore, when polishing an object to be polished that further contains material (b) in addition to material (a), the selectivity of material (b) relative to material (a) is further improved. Furthermore, the content (concentration) of (1) a water-soluble polymer having a polar group is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, relative to the total mass of the polishing composition. Within this range, the effect as a selectivity enhancer is further enhanced. That is, (1) the content of the water-soluble polymer having a polar group is preferably 0.00001% by mass or more and 1% by mass or less, more preferably 0.00005% by mass or more and 0.5% by mass or less, and even more preferably 0.0001% by mass or more and 0.1% by mass or less, relative to the total mass of the polishing composition. When the polishing composition contains two or more water-soluble polymers having a polar group, the above content refers to the total amount thereof.

[0081] When (2) a non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is used as a selectivity enhancer, its content is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, based on the total mass of the polishing composition. This range further enhances the polishing suppression effect of material (a). Furthermore, when polishing an object to be polished that further contains material (b) in addition to material (a), the selectivity of material (b) relative to material (a) is further improved. Furthermore, the content (concentration) of (2) a non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less, based on the total mass of the polishing composition. Within this range, the effect as a selectivity enhancer is enhanced. This is presumably because the electrical conductivity is not excessively high and the electric double layer between the zirconia particles and material (a) is not excessively compressed, thereby maintaining the electrostatic repulsion between the zirconia particles and material (a). Furthermore, this range also ensures better dispersion stability of the slurry. That is, the content of (2) the non-aromatic bridged cyclic compound having an organic acid group or a salt group is preferably 0.001% by mass or more and 10% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less, even more preferably 0.01% by mass or more and 1% by mass or less, even more preferably 0.01% by mass or more and 0.5% by mass or less, and particularly preferably 0.01% by mass or more and 0.3% by mass or less, based on the total mass of the polishing composition. When the polishing composition contains two or more types of non-aromatic bridged cyclic compounds having an organic acid group or a salt group, the above content refers to the total amount of these compounds.

[0082] When (3) anionic surfactant is used as a selectivity enhancer, its content is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, and even more preferably 0.001% by mass or more, based on the total mass of the polishing composition. This range further enhances the polishing suppression effect of material (a). Furthermore, when polishing an object to be polished that further contains material (b) in addition to material (a), the selectivity ratio of material (b) to material (a) is further improved. Furthermore, the content (concentration) of (3) anionic surfactant is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less, based on the total mass of the polishing composition. Within this range, the effect as a selectivity enhancer is enhanced. That is, (3) the content of the anionic surfactant is preferably 0.0001% by mass or more and 1% by mass or less, more preferably 0.0005% by mass or more and 0.5% by mass or less, even more preferably 0.001% by mass or more and 0.1% by mass or less, and particularly preferably 0.001% by mass or more and 0.05% by mass or less, relative to the total mass of the polishing composition. When the polishing composition contains two or more anionic surfactants, the above content refers to the total amount thereof.

[0083] Furthermore, the content (concentration) of the selectivity improving agent may be appropriately selected so that the polishing composition has a desired pH value. In this case, it is preferable to add an amount that will result in the polishing composition having a pH value described later. When such a content (concentration) is adopted, a pH adjuster described later may or may not be used.

[0084] [Dispersion medium] The polishing composition of the present invention contains a dispersing medium for dispersing each component. Examples of dispersing mediums include water; alcohols such as methanol, ethanol, and ethylene glycol; ketones such as acetone; and mixtures thereof. Of these, water is preferred as the dispersing medium. That is, according to a preferred embodiment of the present invention, the dispersing medium contains water. According to a more preferred embodiment of the present invention, the dispersing medium consists essentially of water. Note that the above term "substantially" means that a dispersing medium other than water may be included as long as the intended effect of the present invention can be achieved. More specifically, the dispersing medium preferably consists of 90% by mass to 100% by mass of water and 0% by mass to 10% by mass of a dispersing medium other than water, and more preferably 99% by mass to 100% by mass of water and 0% by mass to 1% by mass of a dispersing medium other than water. Most preferably, the dispersing medium is water.

[0085] From the viewpoint of not inhibiting the action of the components contained in the polishing composition, it is preferable that the dispersion medium be water that contains as few impurities as possible. Specifically, pure water or ultrapure water that has had impurity ions removed using an ion exchange resin and then passed through a filter to remove foreign matter, or distilled water, is more preferable.

[0086] [pH and pH adjusters] The pH of the polishing composition of the present invention is less than 7. If the pH is 7 or higher, the removal rate and selectivity of the organic material (b) decrease.

[0087] The pH is preferably 6.5 or less, more preferably 6 or less. The lower limit of the pH is preferably 1 or more, more preferably 2 or more, and even more preferably 2.5 or more. That is, the pH of the polishing composition of the present invention is preferably 1 or more and 6.5 or less, more preferably 2 or more and 6 or less, and even more preferably 2.5 or more and 6 or less.

[0088] As described above, the selectivity improving agent of the present invention can function as a pH adjuster. Therefore, the polishing composition of the present invention does not need to contain a pH adjuster for adjusting the pH. However, if the desired pH cannot be obtained by adding only the selectivity improving agent, the polishing composition of the present invention may contain a pH adjuster other than the selectivity improving agent. The pH adjuster may be any of an inorganic acid, an organic acid, and a base. The pH adjuster may be used alone or in combination of two or more.

[0089] Specific examples of inorganic acids that can be used as pH adjusters include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Among these, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid are preferred.

[0090] Specific examples of organic acids that can be used as pH adjusters 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-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, and isethionic acid.

[0091] Instead of or in combination with inorganic or organic acids, salts such as alkali metal salts of inorganic or organic acids may be used as pH adjusters. Combinations of a weak acid and a strong base, a strong acid and a weak base, or a weak acid and a weak base can be expected to have a pH buffering effect.

[0092] Specific examples of bases that can be used as pH adjusters include ammonia, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, etc. The amount of pH adjuster added is not particularly limited, and may be appropriately adjusted so that the polishing composition has a desired pH.

[0093] The pH of the polishing composition can be measured, for example, with a pH meter, specifically by the method described in the Examples.

[0094] [Other ingredients] The polishing composition of the present invention may further contain known additives that can be used in polishing compositions, such as an oxidizing agent, a complexing agent, an antiseptic, an antifungal agent, etc., within the range that does not impair the effects of the present invention. Among these, it is preferable to contain an oxidizing agent.

[0095] The oxidizing agent has the effect of oxidizing the surface of the object to be polished, and can further improve the polishing rate of the object to be polished with the polishing composition.

[0096] Examples of oxidizing agents include hydrogen peroxide, sodium peroxide, barium peroxide, ozone water, silver (II) salts, iron (III) salts, permanganic acid, chromic acid, dichromate, peroxodisulfuric acid, peroxolinic acid, peroxosulfuric acid, peroxoboric acid, performic acid, peracetic acid, perbenzoic acid, perphthalic acid, hypochlorous acid, hypobromous acid, hypoiodous acid, chloric acid, chlorous acid, perchloric acid, bromic acid, iodic acid, periodic acid, persulfuric acid, dichloroisocyanuric acid, and salts thereof. These oxidizing agents can be used alone or in combination. Among these, hydrogen peroxide, potassium permanganate, sodium permanganate, ammonium persulfate, periodic acid, hypochlorous acid, and sodium dichloroisocyanurate are preferred, with hydrogen peroxide, potassium permanganate, and sodium permanganate being more preferred, and potassium permanganate being even more preferred.

[0097] The lower limit of the content of the oxidizing agent in the polishing composition is preferably 0.001% by mass or more, and more preferably 0.01% by mass or more. By setting the lower limit in this way, the polishing rate can be further improved. Furthermore, the upper limit of the content of the oxidizing agent in the polishing composition is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 1% by mass or less. By setting the upper limit in this way, it is possible to reduce the material cost of the polishing composition and also to reduce the burden of treating the polishing composition after use in polishing, i.e., waste liquid treatment. It is also possible to reduce the risk of excessive oxidation of the surface of the object to be polished by the oxidizing agent.

[0098] [Method for producing polishing composition] The method for producing the polishing composition of the present invention is not particularly limited, and can be obtained, for example, by stirring and mixing zirconia particles, a selectivity improver, and other additives as needed in a dispersion medium (preferably water). The details of each component are as described above.

[0099] The temperature at which the components are mixed is not particularly limited, but is preferably 10° C. to 40° C. Heating may be used to increase the dissolution rate. The mixing time is also not particularly limited as long as uniform mixing is achieved.

[0100] [Polishing method and semiconductor substrate manufacturing method] As described above, the polishing composition of the present invention is suitable for use in polishing an object having a material (a) having a metal-nitrogen bond and an organic material (b). Accordingly, the present invention provides a polishing method for polishing an object containing a material (a) having a metal-nitrogen bond and an organic material (b) with the polishing composition of the present invention. The present invention also provides a method for producing a semiconductor substrate, comprising polishing a semiconductor substrate containing a material (a) having a metal-nitrogen bond and an organic material (b) by the polishing method.

[0101] As the polishing device, a general polishing device can be used, which is equipped with a holder for holding a substrate or the like having an object to be polished, a motor whose rotation speed can be changed, and a polishing platen onto which a polishing pad (polishing cloth) can be attached.

[0102] The polishing pad may be made of any material, including ordinary nonwoven fabric, polyurethane, porous fluororesin, etc. The polishing pad is preferably provided with grooves to allow the polishing liquid to accumulate.

[0103] Regarding the polishing conditions, for example, the rotation speed of the polishing platen and carrier was 10 rpm (0.17 s -1 ) or more 500rpm (8.33s -1 The pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa).

[0104] The method for supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the polishing composition using a pump, etc. There is no limit to the amount of the polishing composition supplied, but it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.

[0105] After polishing, the substrate is washed with running water, and water droplets adhering to the substrate are removed by a spin dryer or the like, followed by drying, to obtain a substrate having a metal-containing layer.

[0106] The polishing composition of the present invention may be a one-component type or a multi-component type such as a two-component type. The polishing composition of the present invention may also be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more, with a diluent such as water. [Example]

[0107] The present invention will be described in more detail with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Unless otherwise specified, “%” and “parts” mean “mass %” and “parts by mass”, respectively.

[0108] [Measurement methods for various physical properties] In this example, various physical properties were measured by the following methods.

[0109] [Measurement of particle size] For the value of D50 of zirconia particles, the value measured as the volume average particle size by the dynamic light scattering method using a particle size distribution measuring apparatus (UPA-UT151, manufactured by Nikkiso Co., Ltd.) was adopted.

[0110] Using a dispersion liquid in which zirconia particles were dispersed in water, the particle size of the zirconia particles was measured. By analysis using the measuring instrument, in the particle size distribution of the zirconia particles, the diameter D50 of the particles when the integrated particle volume reached 50% of the total particle volume from the fine particle side was calculated.

[0111] [Measurement of zeta potential] The zeta potential of the zirconia particles was measured using a zeta potential measuring apparatus (trade name “ELS-Z”) manufactured by Otsuka Electronics Co., Ltd.

[0112] [Measurement of pH] The pH of the polishing composition was measured using a pH meter (manufactured by Horiba, Ltd., model number: F-71).

[0113] [Weight average molecular weight (Mw)] The molecular weight of the water-soluble polymer having a polar group was measured using the value of the weight average molecular weight (in terms of polyethylene glycol) measured by gel permeation chromatography (GPC). More specifically, it was measured under the following apparatus and conditions: GPC apparatus: manufactured by Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII) Column: VP-ODS (Shimadzu Corporation) Mobile phase A:MeOH B: 1% aqueous solution of acetic acid Flow rate: 1mL / min Detector: ELSD temp. 40℃, Gain 8, N2GAS 350kPa Oven temperature: 40°C Injection volume: 40μL.

[0114] [Preparation of Polishing Composition] Example 1 Colloidal zirconia (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd., NYACOL (registered trademark) ZR70 / 20, zirconia particle concentration: 20 mass%, zirconia particle D50: 70 nm) was prepared as the abrasive grains. 10-Camphorsulfonic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared as the selectivity enhancer.

[0115] Colloidal zirconia and 10-camphorsulfonic acid were added to pure water as a dispersion medium at room temperature (25°C) to a final concentration of 0.1% by mass and 0.05% by mass, respectively, to obtain a mixture. The resulting mixture was stirred and mixed at room temperature (25°C) for 30 minutes to prepare a polishing composition. The pH of the resulting polishing composition was 3.7, and the zeta potential of the colloidal zirconia in the polishing composition was 40 mV. The particle size of the colloidal zirconia in the polishing composition was the same as that of the above-mentioned colloidal zirconia.

[0116] Example 2 A polishing composition was prepared in the same manner as in Example 1, except that colloidal zirconia was added to pure water to a final concentration of 0.5 mass %.

[0117] Example 3 A polishing composition was prepared in the same manner as in Example 1, except that colloidal zirconia was added to pure water to a final concentration of 2.0 mass %.

[0118] Example 4 A polishing composition was prepared in the same manner as in Example 2, except that polyvinylpyrrolidone (PVP, manufactured by Kanto Chemical Co., Inc., weight average molecular weight 8,000) was further added to a final concentration of 0.0001 mass %.

[0119] Example 5 A polishing composition was prepared in the same manner as in Example 4, except that the concentration of polyvinylpyrrolidone was changed to 0.0003% by mass.

[0120] Example 6 A polishing composition was prepared in the same manner as in Example 4, except that polyvinylpyrrolidone having a weight-average molecular weight of 40,000 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used instead of polyvinylpyrrolidone having a weight-average molecular weight of 8,000.

[0121] Example 7 A polishing composition was prepared in the same manner as in Example 4, except that polyvinyl alcohol (PVA, manufactured by Nippon Vaccination & Poval Co., Ltd.) having a weight-average molecular weight of 10,000 was used instead of polyvinylpyrrolidone having a weight-average molecular weight of 8,000.

[0122] Example 8 A polishing composition was prepared in the same manner as in Example 7, except that the concentration of polyvinyl alcohol was changed to 0.0003 mass %.

[0123] Example 9 A polishing composition was prepared in the same manner as in Example 4, except that polyvinyl alcohol (manufactured by Nippon Vaccination & Poval Co., Ltd.) having a weight-average molecular weight of 40,000 was used instead of polyvinylpyrrolidone having a weight-average molecular weight of 8,000.

[0124] Example 10 A polishing composition was prepared in the same manner as in Example 4, except that the concentration of 10-camphorsulfonic acid was changed to 0.1 mass%. The pH of the resulting polishing composition was 3.0. The zeta potential of the colloidal zirconia in the resulting polishing composition was 45 mV.

[0125] Example 11 A polishing composition was prepared in the same manner as in Example 4, except that the concentration of 10-camphorsulfonic acid was changed to 0.01% by mass. The pH of the resulting polishing composition was 5.5. The zeta potential of the colloidal zirconia in the resulting polishing composition was 38 mV.

[0126] Example 12 Except for using colloidal zirconia having a D50 of 100 nm, a polishing composition was prepared in the same manner as in Example 2. The zeta potential of the colloidal zirconia in the obtained polishing composition was 35 mV.

[0127] Example 13 A polishing composition was prepared in the same manner as in Example 5, except that nitric acid, which is a pH adjuster, was used at a concentration of 0.05 mass % instead of 10-camphorsulfonic acid.

[0128] Example 14 A polishing composition was prepared in the same manner as in Example 13, except that sodium 1-hexanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was further added to give a final concentration of 0.01 mass %.

[0129] Example 15 A polishing composition was prepared in the same manner as in Example 13, except that polyvinyl alcohol (manufactured by Nippon Vaccination & Poval Co., Ltd.) having a weight-average molecular weight of 10,000 was used instead of polyvinylpyrrolidone having a weight-average molecular weight of 8,000.

[0130] Example 16 A polishing composition was prepared in the same manner as in Example 13, except that polyvinylpyrrolidone having a weight-average molecular weight of 8,000 was replaced with polyacrylamide (manufactured by Merck Ltd.) having a weight-average molecular weight of 10,000 at a concentration of 0.05 mass%.

[0131] Example 17 A polishing composition was prepared in the same manner as in Example 16, except that 10-camphorsulfonic acid was used instead of nitric acid and the concentration of polyacrylamide was 0.01 mass %.

[0132] Example 18 A polishing composition was prepared in the same manner as in Example 17, except that the concentration of polyacrylamide was 0.05% by mass.

[0133] Example 19 A polishing composition was prepared in the same manner as in Example 17, except that polyacrylamide having a weight-average molecular weight of 400,000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of polyacrylamide having a weight-average molecular weight of 10,000.

[0134] Example 20 A polishing composition was prepared in the same manner as in Example 4, except that ammonium lauryl sulfate (manufactured by Kao Corporation) was used at a concentration of 0.005 mass % instead of polyvinylpyrrolidone having a weight average molecular weight of 8,000.

[0135] Example 21 A polishing composition was prepared in the same manner as in Example 4, except that sodium 1-hexanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used at a concentration of 0.01 mass% instead of polyvinylpyrrolidone having a weight average molecular weight of 8,000.

[0136] Example 22 A polishing composition was prepared in the same manner as in Example 21, except that the concentration of sodium 1-hexanesulfonate was changed to 0.005% by mass.

[0137] (Comparative Example 1) A polishing composition was prepared in the same manner as in Example 2, except that the concentration of 10-camphorsulfonic acid was changed to 0.0001% by mass. The pH of the resulting polishing composition was 7.0. The zeta potential of the colloidal zirconia in the resulting polishing composition was 40 mV.

[0138] (Comparative Example 2) A polishing composition was prepared in the same manner as in Example 13, except that polyvinylpyrrolidone having a weight-average molecular weight of 8,000 was not used.

[0139] (Comparative Example 3) Except for using colloidal zirconia having a D50 of 250 nm, a polishing composition was prepared in the same manner as in Comparative Example 2. The zeta potential of the colloidal zirconia in the obtained polishing composition was 35 mV.

[0140] Comparative Example 4 <Preparing the abrasive grains> In the same manner as described in Example 1 of JP 2005-162533 A, a cocoon-shaped cation-modified colloidal silica having a D50 of 70 nm was prepared using γ-aminopropyltriethoxysilane as a silane coupling agent at a concentration of 2 mmol per 1 L of a methanol solution of silica sol (silica concentration: 20% by mass).

[0141] A polishing composition was prepared in the same manner as in Example 3, except that the cation-modified colloidal silica obtained above was used at a concentration of 2.0 mass% instead of colloidal zirconia, and nitric acid was used as a pH adjuster. The pH of the obtained polishing composition was 3.7. The zeta potential of the cation-modified colloidal silica in the obtained polishing composition was 40 mV.

[0142] (Comparative Example 5) A polishing composition was prepared in the same manner as in Comparative Example 4, except that 10-camphorsulfonic acid was not used.

[0143] The composition of the polishing composition of each Example and Comparative Example is shown in the following Table 1. In the following Table 1, "-" indicates that the agent was not used.

[0144] [Table 1]

[0145] [Polishing speed] The objects to be polished (substrates) were a silicon wafer (Advantec Corporation, 200 mm wafer, SKA, P-type, material (b) substrate) with a 5000 Å thick amorphous carbon film formed on its surface, and a 200 mm wafer (SiN (silicon nitride film), Advanced Materials Technology Corporation, product name: LP-SiN 3.5KA Blanket, material (a) substrate).

[0146] Using the polishing composition obtained above, the prepared substrate was polished under the following polishing conditions, and the removal rate was measured: (polishing conditions) Polishing machine: EJ-380IN-CH (Engis Japan Co., Ltd.) Polishing pad: Hard polyurethane pad (Rohm and Haas, IC1010) Polishing pressure: 1.0 psi (1 psi = 6894.76 Pa) Platen rotation speed: 80 rpm Head (carrier) rotation speed: 60 rpm Flow rate of polishing composition: 100 ml / min Polishing time: 60 seconds.

[0147] (polishing speed) The film thickness was measured using an optical interference film thickness measuring device (manufactured by SCREEN Holdings Co., Ltd., model number: Lambda Ace VM-2030), and the polishing rate was evaluated by dividing the difference in film thickness before and after polishing by the polishing time (see the formula below). The polishing rate for organic material (b) is preferably 90 Å / min or higher.

[0148]

number

[0149] (selectivity) The selectivity was determined by dividing the polishing rate for the organic material substrate obtained above by the polishing rate for the SiN substrate. The selectivity is preferably 30 or more.

[0150] The evaluation results of the polishing compositions of the Examples and Comparative Examples are shown in Table 2 below.

[0151] [Table 2]

[0152] As is clear from Table 2 above, it was found that the polishing compositions of the examples can polish organic material (b) at a high polishing rate and can improve the ratio of the polishing rate of organic material (b) to the polishing rate of material (a) having a metal-nitrogen bond.

Claims

1. A polishing composition used for polishing an object to be polished, the object comprising (a) a material having a metal-nitrogen bond and (b) an organic material, Zirconia particles; a selectivity enhancer that enhances the ratio of the removal rate of the organic material (b) to the removal rate of the material (a) having a metal-nitrogen bond; A dispersion medium; Including, the selectivity improver includes at least one selected from the group consisting of a water-soluble polymer having a polar group and a non-aromatic crosslinked cyclic compound having an organic acid group or a salt thereof; the water-soluble polymer having a polar group includes at least one selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide; The non-aromatic bridged cyclic compound having an organic acid group or a salt thereof is a compound represented by the following general formula 1: In a particle size distribution of the zirconia particles determined by a laser diffraction scattering method, the particle diameter (D50) at which the cumulative particle volume from the fine particle side reaches 50% of the total particle volume is 5 nm or more and 150 nm or less; Polishing composition having a pH of less than 7: 【Chemical 1】 In the general formula 1, Z 1 is CR 1 R 1 ′, C═O, or O; Z 2 is CR 2 R 2 ′, C═O, or O; Z 3 is CR 3 R 3 ′, C═O, or O; Z 4 is CR 4 R 4 ′, C═O, or O; R 1 , R 1 ', R 2 , R 2 ', R 3 , R 3 ', R 4 , R 4 ', R 5 , R 6 , R 7 , and R 8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; When at least one of R 1 , R 1 ', R 2 , R 2 ', R 3 , R 3 ', R 4 , R 4 ', R 5 , R 6 , R 7 , and R 8 is a substituted group, the substituents are each independently a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkenyl group, an unsubstituted alkynyl group, an unsubstituted alkoxy group, an unsubstituted polyoxyalkylene group, or an organic acid group or a salt thereof; At least one of R 1 , R 1 ', R 2 , R 2 ', R 3 , R 3 ', R 4 , R 4 ', R 5 , R 6 , R 7 , and R 8 includes an organic acid group or a salt thereof.

2. 2. The polishing composition according to claim 1, wherein the compound represented by general formula 1 is 10-camphorsulfonic acid.

3. The polishing composition according to claim 1 or 2, wherein the selectivity enhancer further contains an anionic surfactant.

4. A polishing method comprising the step of polishing an object to be polished, the object comprising a material (a) having a metal-nitrogen bond and an organic material (b), using the polishing composition according to any one of claims 1 to 3.

5. A method for producing a semiconductor substrate, comprising a step of polishing a semiconductor substrate containing a material (a) having a metal-nitrogen bond and an organic material (b) by the polishing method according to claim 4.

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