TWI609950B - Honing composition - Google Patents

Abstract

The invention provides a polishing composition which can be stably used for polishing a material containing metal, especially tungsten, and can improve the polishing speed.

The present invention is a polishing composition comprising a metal element-containing oxo acid and a stabilizer for the metal element-containing oxo acid.

Description

Polishing composition

The present invention relates to a polishing composition, and more particularly to a polishing composition suitable for polishing a metal-containing material.

Since the past, new microfabrication technologies have been developed as LSIs have become more integrated and more efficient. The chemical mechanical polishing (hereinafter also referred to as "CMP") method is also one of them. It is related to the LSI manufacturing steps, especially the planarization of the interlayer insulating film in the multilayer wiring formation step, the formation of metal plungers, and the embedded wiring (embedded (embedded ( Damascene (wiring) is often used in the formation of technology.

A method of forming a wiring structure using CMP is to first form a metal layer including a conductor layer on an insulator layer forming a recessed portion so that at least the recessed portion is completely buried. Then, the conductor layer is polished and removed until the insulator layer in a portion other than the concave portion is exposed, and a wiring portion is formed in the concave portion. Such CMP applied to the metal layer is called metal CMP.

The general method of metal CMP is to attach a polishing pad to a circular polishing platen, impregnate the surface of the polishing pad with an abrasive, and press it against the metal film-forming surface of the substrate, and apply a specific pressure from its back surface (The following also Grinding pressure plate is rotated under the condition of grinding pressure), and the metal film of the convex portion is removed by mechanical friction between the abrasive and the convex portion of the metal film.

The target metal in metal CMP is currently copper, but tungsten is sometimes used. Tungsten is less susceptible to chemistry than copper and does not exhibit abrasiveness. It is therefore required to exhibit a high grinding speed.

As for the polishing composition used in the so-called metal CMP, a polishing composition disclosed in Japanese Patent Application Laid-Open No. 2001-247853 is characterized in that it contains an abrasive, an anticorrosive agent, hydrogen peroxide as an oxidant, and a pH Within the range of 2 to 5, and the aforementioned abrasive material is colloidal silica or fumed silica, the primary particle diameter of the abrasive material is 20 nm or less. In addition, Japanese Patent Application Laid-Open No. 2002-43260 discloses a method of etching copper or a copper alloy with aminoacetic acid by forming an oxide film that functions as an etching barrier on the surface of copper or a copper alloy by an oxidizing agent.

However, the abrasives described in Japanese Patent Application Laid-Open No. 2001-247853 or Japanese Patent Application Laid-Open No. 2002-43260 cannot obtain a sufficient polishing rate for metals, especially tungsten, and cannot be called an effective polishing method for metals, especially tungsten.

Therefore, an object of the present invention is to provide a polishing composition which can be used stably for polishing a metal-containing material, especially tungsten, and can improve the polishing speed.

In order to solve the above-mentioned problems, the present inventors and the like have actively repeated intensive studies. As a result, it was found that by using an oxo acid containing a metal element and the aforementioned metal The polishing composition for the stabilizer of the oxyacid of the element can solve the above problems. Accordingly, the present invention has been completed based on the above findings.

That is, the present invention is a polishing composition containing a stabilizer containing a metal element-containing oxo acid and the aforementioned metal element-containing oxo acid.

The present invention is a polishing composition comprising a metal element-containing oxo acid and the aforementioned metal element-containing oxo acid stabilizer. With this structure, it can be used stably for polishing of metal-containing materials (especially tungsten), and the polishing speed of metal-containing materials (especially tungsten) can be improved.

Although the detailed reason for improving the polishing rate of a metal (especially tungsten) -containing material by using the polishing composition of the present invention is not clear, it is presumed to be the following mechanism. The following describes the case where the metal-containing material is a tungsten-containing material. Tungsten usually undergoes a state change due to chemical reactions such as oxidation, and this part is polished by friction. That is, by a faster oxidation of tungsten, an improvement in tungsten grinding rate can be exhibited.

Oxygen acids containing metal elements have the effect of promoting oxidation and reacting with metals to generate free radicals. It is believed that the oxo acid containing a metal element forms an oxide film on the surface of tungsten, and simultaneously generates radicals, and the radicals accelerate the oxidation. With only oxo acids containing metal elements, the oxidation state of the metal elements contained in the oxo acid is unstable and will change to an oxidation state that cannot fully exhibit the polishing rate. As a result, the polishing rate is reduced, and the oxidation state is changed to cause the problem of precipitating the oxide of the metal element. On the other hand, when the stabilizer of the oxo acid containing the metal element is added, the metal element can be made It is believed that the oxidation state is stabilized, and it is considered to be a person who can easily exhibit a stable state of rapid polishing speed. As a result, to the extent that the industry cannot expect, the present invention can not only improve the polishing rate of tungsten, but also stabilize the user. The above-mentioned mechanism is speculative, and the present invention is not limited in any way by the above-mentioned mechanism.

[Object to be polished]

The object to be polished in the present invention is not particularly limited, and a substrate having a metal-containing layer is preferred. The metal is not particularly limited, but is preferably a transition metal. Examples of the transition metal include tungsten, copper, rhenium, cobalt, nickel, titanium, and tantalum. Better for tungsten. The above metals may be in the form of an alloy or a metal compound. These materials can be used alone or in combination of two or more.

Next, the structure of the polishing composition of the present invention will be described in detail.

[Oxygen containing metal elements]

The polishing composition of the present invention must contain a metal element-containing oxyacid as a characteristic constituent.

"Oxo-acid" is also referred to as oxy acid and oxy acid. It is an acid in which proton-dissociated hydrogen and oxygen atoms are bonded, and is represented by the general formula XO _n (OH) _m . In the general formula, X represents a central element, but the metal element-containing oxo acid of the present invention means that X is a metal element.

The so-called "metal element" means an element whose element exhibits the properties of "having metallic luster, rich in ductility, ductility, and significant conductivity of electricity and heat", and its concept includes all elements known as "metal elements" in the past. Such Metal elements include, for example, tungsten (W), molybdenum (Mo), vanadium (V), manganese (Mn), copper (Cu), iron (Fe), aluminum (Al), cobalt (Co), tantalum (Ta), tin (Sn), gallium (Ga), indium (In), zinc (Zn), lead (Pb), and niobium (Nb), but the best is vanadium (V).

Specific examples of the oxo acid containing a metal element are not particularly limited, and examples thereof include the oxo acid containing the above metal element. More specifically include, for example, tungstic acid _{(H 2 WO 4 (WO 3} .H 2 O), H 4 WO 5 (WO 3 .2H 2 O)), metatungstic acid, molybdate (MoO ₃ .H ₂ O), Metamolybdic acid, silicotungstic acid (H ₄ [SiW ₁₂ O ₄₀ ]), phosphotungstic acid (H ₃ [PW ₁₂ O ₄₀ ]), metavanadic acid (HVO ₃ ), permanganic acid, aluminaic acid, stannic acid, etc. . It can also be used in combination of two or more kinds of oxo acids.

In this specification, the concept of "oxyacid" also includes those in the form of salts or hydrates. The salt of an oxyacid is a salt of an anion and a suitable cation having a structure in which a proton (H ⁺ ) is released from the above-mentioned oxyacid. Examples of the cation constituting the salt of an oxoacid include alkali metals such as sodium and potassium, alkaline earth metals such as calcium, ammonium ions (NH ₄ ⁺ ), primary amines, secondary amines, tertiary amines, and quaternary amine cations. In addition, the number of water molecules hydrated with the oxo acid in the hydrate of the oxo acid is not particularly limited, and reference may be made to the conventionally known insights as appropriate.

Furthermore, among the oxo acids containing metal elements, the oxo acid is preferably a partial acid. The so-called meta acid is an acid having a low degree of hydration in an oxo acid in which a metal and a proton-dissociated hydrogen are bonded to an oxygen atom, and is not an ortho acid. Here, the term "low hydration degree" means that the number of water molecules added to a certain chemical species is small. When the degree of hydration is low, reactivity is high because the substance is unstable. Therefore, it is thought that the metal-containing meta-acid has high reactivity and can promote faster oxidation. The above mechanism is speculative, and the present invention is not limited by this. Any restrictions on the above mechanisms. These metal element-containing partial acids can be used alone or in combination of two or more.

Examples of the metal element-containing meta-acid include metavanadic acid, metatungstic acid, and metamolybdic acid. Among these, metavanadate is more preferable.

The lower limit of the content (concentration) of the oxo acid of the aforementioned metal element in the polishing composition of the present invention is not particularly limited because it can exhibit effects even in a small amount, but it is preferably 0.001 mol / L (hereinafter abbreviated as M) The above is more preferably 0.005M or more, and most preferably 0.01M or more. The upper limit of the content (concentration) of the oxo acid of the metal element in the polishing composition of the present invention is preferably 3M or less, more preferably 1M or less, and still more preferably 0.5M or less. If it is this range, the effect of this invention can be acquired more effectively.

[Stabilizing agent for oxo acids containing metal elements]

The polishing composition of the present invention includes a stabilizing agent of an oxo acid containing a metal element as a characteristic constituent. The so-called stabilizer containing an oxo acid of a metal element is a compound having a functional group capable of chelating with a metal element contained in an oxo acid, and examples thereof include compounds having a phosphate group or a phosphonic acid group. The number of the aforementioned functional groups in the compound is not particularly limited, but a compound having two or more is preferable. This stabilizer can be used alone or in combination of two or more.

Specific examples of compounds that can be used as stabilizers for oxoacids containing metal elements include phosphoric acid compounds such as phosphoric acid, phosphorous acid, pyrophosphoric acid, and polyphosphoric acid, and alkyldiphosphonic acids such as phosphonic acid and butyldiphosphonic acid. Compounds, alkylene diphosphonic acid, 1-hydroxyethylene-1,1-diphosphonic acid, etc. Compounds, amino phosphonic acid compounds such as nitroshen methylenephosphonic acid, ethylenediamine tetramethylenephosphonic acid, and the like. Among these, from the viewpoint of stability, phosphoric acid, phosphorous acid, pyrophosphoric acid, polyphosphoric acid, 1-hydroxyethylene-1,1-diphosphonic acid is more preferable, and pyrophosphoric acid and polyphosphoric acid are more preferable.

The concentration of the stabilizer is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.1% by mass or more. The upper limit of the content (concentration) of the stabilizer in the polishing composition of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 1% by mass or less. If it is this range, precipitation of an oxide can be suppressed. As a result, in addition to suppressing the occurrence of scratches on the surface of the object to be polished after polishing with the polishing composition, the polishing rate can be stably provided.

[Other ingredients]

The polishing composition of the present invention may further contain an oxidizing agent, a pH adjusting agent, water, abrasive particles, a disproportionating agent, a metal anticorrosive agent, an anticorrosive agent, an antifungal agent, a reducing agent, a polymer, a surfactant, and the like, as needed. Other components such as organic solvents that dissolve poorly soluble organic substances. The oxidizing agents, pH adjusting agents, water, abrasive particles, metal anticorrosive agents, anticorrosive agents, and antifungal agents of other components will be described below.

[Oxidant]

The polishing composition of the present invention may also contain an oxidant, but the content of the oxidant is less preferred. When there are too many oxidants, the oxidation state of the oxyacid containing metal elements will change, and as a result, the polishing speed will be reduced or the stability will be reduced. Reduced case.

Specific examples of the oxidant include peroxides such as hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchloric acid, sodium persulfate, potassium persulfate, and ammonium persulfate. The upper limit of the content of the oxidant is preferably 500 mass ppm or less, more preferably 200 mass ppm or less, and more preferably no oxidizer relative to the total mass of the polishing composition.

[pH adjuster]

The pH adjusting agent used in the polishing composition of the present invention may be any one of an acid and an alkali, and may be any one of an inorganic compound and an organic compound. Specific examples of the acid include inorganic acids such as sulfuric acid, nitric acid, boric acid, and carbonic acid; formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, N-hexanoic acid, and 3,3-dimethyl Butyric acid, 2-ethylbutanoic acid, 4-methylvaleric acid, N-heptanoic acid, 2-methylhexanoic acid, N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, Glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid and lactic acid, etc. And organic acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid. Specific examples of the base include amines such as sodium hydroxide, potassium hydroxide, ammonia, ethylenediamine, and piperazine, and quaternary ammonium salts such as tetramethylammonium and tetraethylammonium. These pH adjusting agents can be used alone or in combination of two or more.

The pH of the polishing composition of the present invention can be adjusted by the aforementioned pH adjusting agent. The lower limit of the pH of the polishing composition of the present invention is not particularly limited, but from the viewpoint of safety, it is preferably 1 or more, more preferably 1.5 or more Up, and more preferably 2 or more. In addition, the upper limit of the pH of the polishing composition of the present invention is not particularly limited, but in order to prevent dissolution of the abrasive particles, it is preferably 13 or less, more preferably 12.5 or less, and even more preferably 12 or less.

[water]

The polishing composition of the present invention may also contain water as a dispersion medium or solvent for dispersing or dissolving each component. From the standpoint of suppressing the effects of impeding other components, water containing no impurities as much as possible is preferable, and specifically, pure water or ultrapure water for removing foreign matter by a filter after removing impurity ions with an ion exchange resin is preferable. , Or distilled water.

[Abrasive particles]

The abrasive composition of the present invention may also contain abrasive particles. The abrasive particles have a function of mechanically polishing the object to be polished, and the polishing rate of the object to be polished is increased by the polishing composition.

The abrasive particles used may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of the inorganic particles include particles made of metal oxides such as silicon dioxide, aluminum oxide, cerium oxide, and titanium oxide, and silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. These abrasive grains can be used individually or in mixture of 2 or more types. As the abrasive grains, a commercially available product or a synthetic product can be used.

Of these abrasive particles, silica is preferred, and colloidal silica is most preferred.

The abrasive particles can also be surface modified. Generally, colloidal silicon dioxide has a Zeta potential value close to zero under acidic conditions, so the silicon dioxide particles do not repel each other statically under acidic conditions and easily cause aggregation. On the other hand, even under acidic conditions, the surface-modified abrasive particles having a large positive or negative Zeta potential are strongly repelled from each other under acidic conditions, resulting in good dispersion, which improves the storage of the polishing composition. Stability. Such surface-modified abrasive particles can be obtained, for example, by mixing a metal such as aluminum, titanium, or zirconium, or an oxide thereof with the abrasive particles, and doping the surface of the abrasive particles.

Among them, the surface-modified abrasive particles in the polishing composition may also be colloidal silicon dioxide to which an organic acid is immobilized. Among them, colloidal silica with immobilized organic acid is preferred. The immobilization of colloidal silica by an organic acid is performed by chemically bonding functional groups of the organic acid to the surface of colloidal silica. The coexistence of colloidal silica and organic acid alone cannot bring about the fixation of colloidal silica with organic acid. If a sulfonic acid, which is an organic acid, is immobilized on colloidal silicon dioxide, it can be described by, for example, "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003) Method. Specifically, a thiol group-containing silane coupling agent such as 3-mercaptopropyltrimethoxysilane is coupled to colloidal silicon dioxide, and then the thiol group is oxidized with hydrogen peroxide to obtain sulfonic acid fixation. Colloidal silica on the surface. Alternatively, if the carboxylic acid is immobilized on colloidal silicon dioxide, for example, "Novel Silane Coupling Agents Containing a Photo labile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel", Chemistry Letters, 3 , The method described in 228-229 (2000) was performed. Specifically, a colloidal silica having a photoreactive 2-nitrobenzyl ester-containing silane coupling agent coupled to the colloidal silica is irradiated with light to obtain a colloidal silica having a carboxylic acid immobilized on the surface.

The lower limit of the average primary particle diameter of the abrasive grains is preferably 5 nm or more, more preferably 7 nm or more, and even more preferably 10 nm or more. The upper limit of the average primary particle diameter of the abrasive particles is preferably 500 nm or less, more preferably 100 nm or less, and even more preferably 70 nm or less. Within this range, the polishing rate of the polishing composition to the polishing object is increased, and further, depressions on the surface of the polishing object after polishing using the polishing composition can be further suppressed. The average primary particle diameter of the abrasive particles was calculated based on the specific surface area of the abrasive particles measured by the BET method.

The lower limit of the content of the abrasive grains in the polishing composition is 100% by mass relative to the total amount of the composition, preferably 0.001% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and most preferably 1% by mass or more. In addition, the upper limit of the content of the abrasive particles in the polishing composition is 100% by mass based on the total amount of the composition, preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 15% by mass or less. Within this range, the polishing speed of the polishing target can be increased, the cost of the polishing composition can be suppressed, and scratches on the surface of the polishing target after polishing with the polishing composition can be further suppressed.

[Metal anticorrosive]

The polishing composition of the present invention may also contain a metal anticorrosive. By The addition of a metal anticorrosive to the polishing composition can further suppress the occurrence of depressions on the sides of the wiring due to polishing with the polishing composition. In addition, it is possible to further suppress the occurrence of depressions on the surface of the object to be polished after polishing with the polishing composition.

The metal anticorrosive agent that can be used is not particularly limited, but is preferably a compound having a phenyl group, a heterocyclic compound, or a surfactant. The number of heterocyclic members in the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having a condensed ring. This metal anticorrosive agent can be used individually or in mixture of 2 or more types. In addition, as the metal anticorrosive, a commercially available product or a synthetic product may be used.

Specific examples of the compound having a phenyl group that can be used as a metal anticorrosive include compounds such as benzenesulfonic acid.

Specific examples of the heterocyclic compound include, for example, a pyrrole compound, a pyrazole compound, an imidazole compound, a triazole compound, a tetrazole compound, a pyridine compound, a piperidine compound, a pyrimidine compound, a pyrazine compound, an indolizine compound, and indium. Indole compound, isoindole compound, indazole compound, purine compound, quinolizine compound, quinoline compound, isoquinoline compound, naphthyridine compound, phthalazine compound, quinoxaline compound, quinazoline compound, hydrazone Nitrogen-containing heterocyclic compounds such as a phosphonium compound, a pyridine compound, a thiazole compound, an isothiazole compound, an oxazole compound, an isoxazole compound, and a furazine compound.

If specific examples are further listed, examples of the pyrazole compound include 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, and 3-amino-5-phenyl group. Pyrazole, 5-amino-3-phenylpyrazole, 3,4,5-tribromopyrazole, 3-amino Pyrazole, 3,5-dimethylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3-methylpyrazole, 1-methylpyrazole, 3-amino-5- Methylpyrazole, 4-amino-pyrazolo [3,4-D] pyrimidine, allopurinol, 4-chloro-1H-pyrazolo [3,4-D] pyrimidine, 3,4 -Dihydroxy-6-methylpyrazolo (3,4-B) pyridine, 6-methyl-1H-pyrazolo [3,4-B] pyridin-3-amine, and the like.

Specific examples of the imidazole compound include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2- Isopropylimidazole, benzimidazole, 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2- (1-hydroxyethyl Group) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2,5-dimethylbenzimidazole, 5-methylbenzimidazole, 5-nitrobenzimidazole, 1H- Purines and so on.

Examples of triazole compounds include 1,2,3-triazole, 1,2,4-triazole, 1-methyl-1,2,4-triazole, and methyl-1H-1,2,4 -Triazole-3-carboxylic acid ester, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole-3-carboxylic acid methyl ester, 1H-1,2,4-triazole -3-thiol, 3,5-diamino-1H-1,2,4-triazole, 3-amino-1,2,4-triazole-5-thiol, 3-amino-1H -1,2,4-triazole, 3-amino-5-benzyl-4H-1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4-tri Azole, 3-nitro-1,2,4-triazole, 3-bromo-5-nitro-1,2,4-triazole, 4- (1,2,4-triazol-1-yl) Phenol, 4-amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1,2,4-triazole, 4-amino-3,5-di Methyl-4H-1,2,4-triazole, 4-amino-3,5-dipentyl-4H-1,2,4-triazole, 5-methyl-1,2,4-triazole Azole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole Azole, 5-nitro-1H-benzotriazole, 5-carboxy- 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1- (1 ', 2'-dicarboxyethyl) benzo Triazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -5-methylbenzene Benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, and the like.

Examples of the tetrazole compound include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, and 5-phenyltetrazole.

Examples of the indazole compound include, for example, 1H-indazole, 5-amino-1H-indazole, 5-nitro-1H-indazole, 5-hydroxy-1H-indazole, 6-amino-1H-ind Azole, 6-nitro-1H-indazole, 6-hydroxy-1H-indazole, 3-carboxy-5-methyl-1H-indazole and the like.

Specific examples of the indole compound include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, and 4-methyl-1H- Indole, 5-methyl-1H-indole, 6-methyl-1H-indole, 7-methyl-1H-indole, 4-amino-1H-indole, 5-amino-1H- Indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydroxy-1H-indole, 5-hydroxy-1H-indole, 6-hydroxy-1H-indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6-methoxy-1H-indole, 7-methoxy-1H- Indole, 4-chloro-1H-indole, 5-chloro-1H-indole, 6-chloro-1H-indole, 7-chloro-1H-indole, 4-carboxy-1H-indole, 5- Carboxy-1H-indole, 6-carboxy-1H-indole, 7-carboxy-1H-indole, 4-nitro-1H-indole, 5-nitro-1H-indole, 6-nitro- 1H-indole, 7-nitro-1H-indole, 4-nitryl-1H-indole, 5-nitryl-1H-indole, 6-nitryl-1H-indole, 7-nitrile- 1H-indole, 2,5-dimethyl-1H-indole, 1,2-dimethyl-1H-indole, 1,3-dimethyl 1H-indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H-indole, 7-ethyl-1H-indole, 5- (Aminomethyl) indole, 2-methyl-5-amino-1H-indole, 3-hydroxymethyl-1H-indole, 6-isopropyl-1H-indole, 5-chloro- 2-methyl-1H-indole and the like.

Among these, the preferred heterocyclic compounds are triazole compounds, most preferably 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methyl Benzotriazole, 1,2,3-triazole, and 1,2,4-triazole. Since these heterocyclic compounds have high chemical or physical adsorption force on the surface of the object to be polished, a stronger protective film can be formed on the surface of the object to be polished. This is advantageous for improving the surface flatness of the object to be polished after polishing using the polishing composition of the present invention.

The surfactant used as the metal anticorrosive agent is any of anionic surfactant, cationic surfactant, amphoteric surfactant, and nonionic surfactant.

Examples of the anionic surfactant are polyoxyethyl ether ether acetic acid, polyoxyethyl ether alkyl sulfate, alkyl sulfate, polyoxy ethyl ether ether sulfuric acid, alkyl ether sulfuric acid, alkyl Benzene sulfonic acid, alkyl phosphate, polyoxyethyl ethyl alkyl phosphate, polyoxy ethyl sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether di Sulfonic acid, and salts thereof.

Examples of the cationic surfactant include an alkyltrimethylammonium salt, an alkyldimethylammonium salt, an alkylbenzyldimethylammonium salt, and an alkylamine salt.

Examples of the amphoteric surfactant include alkyl betaine, alkyl amine oxide, and the like.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, and Oxyalkylammonium, and alkylalkanolamide.

The preferred surfactants among these are polyoxyethyl ether ether acetate, polyoxy ethyl ether ether sulfate, alkyl ether sulfate, alkyl benzene sulfonate, and polyoxyethyl ether. Alkyl ether. These surfactants have a high chemical or physical adsorption force on the surface of the polishing object, so they can form a stronger protective film on the surface of the polishing object. This is advantageous for improving the flatness of the surface of the object to be polished after polishing using the polishing composition of the present invention.

The lower limit of the content of the metal anticorrosive in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and still more preferably 0.01 g / L or more. On the other hand, the upper limit of the content of the metal anticorrosive in the polishing composition is preferably 50 g / L or less, more preferably 25 g / L or less, and still more preferably 10 g / L or less. Within this range, the surface flatness of the object to be polished after polishing with the polishing composition can be improved, and the polishing rate of the object to be polished by the polishing composition can be maintained.

[Anti-corrosive agent and mildew-proof agent]

Examples of the anticorrosive agent and antifungal agent used in the present invention include isothiazol such as 2-methyl-4-isothiazolin-3-one or 5-chloro-2-methyl-4-isothiazolin-3-one Phenoline corrosion inhibitors, peroxybenzoates, and phenoxyethanol. These anti-corrosive agents and anti-mildew agents can be used alone or in combination of two or more.

[Manufacturing method of polishing composition]

The method for producing the polishing composition of the present invention is not particularly limited, and it is possible to stir and mix a metal element-containing oxyacid, a metal element-containing oxoacid stabilizer, and the like in a solvent such as water or a dispersion medium, and Calculated as needed.

The order of addition is not particularly limited, but it is preferable to add a metal element-containing oxo acid, and then add the aforementioned metal element-containing oxo acid stabilizer, and the abrasive particles are added last when the abrasive particles are added.

The temperature at which the components are mixed is not particularly limited, but is preferably 10 to 40 ° C, and may be heated to increase the dissolution rate. The mixing time is not particularly limited.

[Polishing method and manufacturing method of substrate]

As described above, the polishing composition of the present invention is more suitable for polishing an object to be polished having a metal-containing layer, particularly a tungsten-containing layer. Accordingly, the present invention provides a polishing method for polishing an object to be polished having a layer containing a metal (particularly tungsten) with the polishing composition of the present invention. The present invention also provides a substrate manufacturing method including a step of polishing an object to be polished having a metal-containing layer (particularly tungsten) by the aforementioned polishing method.

As the polishing device, a carrier on which a substrate having an object to be polished and the like is mounted, a motor with a variable number of rotations, etc., and a polishing pad (researchable) (Abrasive cloth) General grinding device for grinding platen.

The polishing pad may be a general non-woven fabric, a polyurethane, a porous fluororesin, or the like without particular limitation. The polishing pad is preferably provided with a groove process capable of accumulating polishing liquid.

The polishing conditions are also not particularly limited. For example, the number of rotations of the polishing platen is preferably 10 to 500 rpm, and the pressure (polishing pressure) applied to the substrate having the object to be polished is preferably 0.5 to 10 psi. The method for supplying the polishing composition to the polishing pad is also not particularly limited, and for example, a method of continuously supplying a pump or the like can be used. The supply amount is not limited, but it is preferable to cover the polishing pad surface with the polishing composition of the present invention at any time.

After the polishing is completed, the substrate is washed in a stream of water, and the water droplets attached to the substrate are removed by a rotary dryer or the like and dried to obtain a substrate having a metal-containing layer.

[Example]

The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following embodiments.

(Examples 1 to 11, Comparative Examples 1 to 14)

With the composition shown in Table 1, the abrasive particles, the oxo acid containing a metal element, the stabilizer of the oxo acid containing the above metal element, a non-metal oxidant, and nitric acid and hydroxide as a pH adjuster are mixed in water. Potassium, thereby obtaining a polishing composition (mixing temperature: about 25 ° C, mixing time: about 10 minutes). In addition, "-" in Table 1 means that the agent is not contained.

The pH of the polishing composition was checked with a pH meter. In addition, the abrasive particles shown in Table 1 are silicon dioxide (average primary particle size: 35 nm, average secondary particle size: 68 nm) with sulfonic acid immobilized on the surface, and "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups" ", Method maker described in Chem. Commun. 246-247 (2003).

Using the obtained polishing composition, the polishing rate when the polishing target was polished under the following polishing conditions was measured.

<Polishing conditions>

(1) Grinder: single-sided CMP grinder

(2) polishing pad: pad made of polyurethane

(3) Pressure: 2.64psi (about 18.2kPa)

(4) Platen rotation speed: 40rpm

(5) Carrier rotation speed: 60rpm

(6) Flow rate of polishing composition: 100ml / min

(7) Grinding time: 1 minute

(8) Object to be polished: tungsten wafer

The polishing rate is calculated by the following formula.

Grinding speed [Å / min] = film thickness change during 1 minute of grinding

Here, the film thickness is measured by a sheet resistance measuring device based on the DC 4-probe method. The measurement results of the polishing rate are shown in Table 2.

<Presence or absence of oxide precipitation>

The presence or absence of oxide precipitation was evaluated by keeping the polishing composition at 60 ° C. for 24 hours by visually confirming the presence of solid precipitation. The results are shown in Table 2 below. When there is no precipitation, it is described as "none", and when there is precipitation, it is described as "yes".

As can be understood from the results of the tungsten polishing rate in Table 2 above, when the polishing composition of the present invention of Examples 1 to 11 is used, it can be seen that the polishing rate of tungsten of the object to be polished is high. In addition, no precipitation of oxides was confirmed in the polishing compositions of the examples.

On the other hand, the polishing rate of tungsten of the polishing compositions of Comparative Examples 1 and 2 was insufficient. In the polishing compositions of Comparative Examples 3 to 14, oxide precipitation was confirmed, and it was confirmed that they could not be used stably. So no grinding Evaluation of speed. Therefore, it can be seen that the polishing composition containing the stabilizing agent of a metal element-containing oxyacid and a metal element-containing oxoacid stabilizer of the present invention can increase the polishing rate of tungsten and can be used stably.

The present application is based on Japanese Patent Application No. 2013-63821 filed on March 26, 2013, the disclosure of which is incorporated by reference in its entirety.

Claims (7)

A polishing composition comprising an oxo acid containing a metal element, a stabilizer for the oxo acid containing the metal element, and abrasive particles, wherein the oxo acid containing the metal element is selected from the group consisting of tungstic acid and metatungsten At least one of the group consisting of an acid, silicotungstic acid, phosphotungstic acid, and metavanadic acid, and the stabilizer of the oxo acid containing the metal element is selected from the group consisting of a phosphoric acid compound, a phosphonic acid, an alkyl diphosphonic acid compound, and ethylene At least one of the group consisting of a diphosphonic acid and an aminophosphonic acid compound. The polishing composition according to claim 1, wherein the abrasive particles are silicon dioxide. The polishing composition according to claim 1, wherein the metal-containing oxyacid is a meta acid. The polishing composition according to any one of claims 1 to 3 is used for polishing an object to be polished having a metal-containing layer. The polishing composition according to claim 4, wherein the aforementioned metal is a transition metal. A polishing method for polishing an object to be polished having a metal-containing layer with the polishing composition according to any one of claims 1 to 5. A method for manufacturing a substrate, comprising the step of polishing an object to be polished having a metal-containing layer by a polishing method as claimed in claim 6.