JP6396741B2 - Polishing composition, method for producing the same, and polishing method - Google Patents

Description

  The present invention relates to a polishing composition, a method for producing the same, and a polishing method.

In the manufacturing process of a semiconductor device, there is a step of polishing an object to be polished such as single silicon (Si), silicon compound, metal, etc. For example, silicon nitride (Si ₃ N ₄ ) having poor chemical reactivity is polished at a high polishing rate. Polishing is required. Many of the polishing compositions conventionally used for polishing silicon nitride contain abrasive grains and acids. For example, Patent Document 1 discloses a polishing composition containing phosphoric acid or a phosphoric acid derivative. Patent Document 2 discloses a polishing composition containing colloidal silica and an organic acid having a sulfonic acid group or a phosphonic acid group. Further, Patent Document 3 discloses an acidic polishing composition containing colloidal silica in which an organic acid such as sulfonic acid or carboxylic acid is immobilized. However, these conventional polishing compositions do not sufficiently satisfy the user's requirements regarding the polishing rate of silicon nitride.

JP-A-6-124932 JP 2010-41037 A JP 2012-40671 A

  Therefore, the present invention solves the above-mentioned problems of the prior art, and a polishing composition capable of polishing an object to be polished such as single silicon, silicon compound, metal, etc., particularly silicon nitride at a high polishing rate. It is an object to provide an object, a manufacturing method thereof, and a polishing method.

In order to solve the above problems, a polishing composition according to one embodiment of the present invention contains colloidal silica having an organic acid immobilized on the surface, and a heterocyclic compound containing two or more nitrogen atoms in the ring. The gist is to do.
In the polishing composition according to the above aspect, the heterocyclic compound may be at least one selected from imidazole derivatives and pyrazole derivatives. The heterocyclic compound may be a 5-membered ring compound. Further, the heterocyclic compound is imidazole, 1,2-dimethylimidazole, 2-methylimidazole, 2-aminobenzimidazole, pyrazole, 1-methylpyrazole, 3,5-dimethylpyrazole, 3,5-pyrazole dicarboxylic acid hydration. And at least one selected from 3-amino-5-methylpyrazole.

Furthermore, the polishing composition according to the above aspect may have a pH of 7 or less.
Furthermore, in the polishing composition according to one aspect, the organic acid may be at least one selected from sulfonic acid, carboxylic acid, sulfinic acid, and phosphonic acid.
Furthermore, in the polishing composition according to the above aspect, the content of the heterocyclic compound may be 0.01% by mass or more and 1% by mass or less.
Furthermore, the polishing composition according to the above-described embodiment can be used for polishing silicon nitride.

Another aspect of the polishing method according to the present invention is to polish an object to be polished using the polishing composition according to the above aspect. In this polishing method, the object to be polished may be silicon nitride.
Furthermore, the manufacturing method of the polishing composition according to another aspect of the present invention is a method of manufacturing the polishing composition according to the above-described aspect, wherein the colloidal silica, the heterocyclic compound, and the liquid medium are mixed. It is made to include.
Furthermore, the gist of the substrate according to another aspect of the present invention is that the surface is polished using the polishing composition according to the above aspect.
Furthermore, the gist of the substrate manufacturing method according to another aspect of the present invention includes polishing the surface of the substrate using the polishing composition according to the above aspect.

  The polishing composition and polishing method of the present invention can polish an object to be polished such as simple silicon, silicon compound, metal, etc. at a high polishing rate. Moreover, the manufacturing method of the polishing composition of this invention can manufacture the polishing composition which grind | polishes grinding | polishing objects, such as a single-piece | unit silicon, a silicon compound, a metal, at a high polishing rate.

  Embodiments of the present invention will be described in detail. The polishing composition of the present embodiment contains colloidal silica having an organic acid immobilized on the surface and a heterocyclic compound containing two or more nitrogen atoms in the ring. This polishing composition is obtained by mixing colloidal silica having an organic acid immobilized on the surface, a heterocyclic compound containing two or more nitrogen atoms in the ring, and a liquid medium such as water or an organic solvent. Can be manufactured.

  This polishing composition is used for polishing an object to be polished such as single silicon, silicon compound, metal, etc., for example, polishing the surface of a semiconductor wiring substrate containing single silicon, silicon compound, metal, etc. in a semiconductor device manufacturing process. It is suitable for the use to do. And it is especially suitable for the use which grind | polishes a silicon nitride. When polishing is performed using this polishing composition, it is possible to polish an object to be polished such as single silicon, silicon compound, metal, etc., particularly silicon nitride, at a high polishing rate.

Below, the polishing composition of this embodiment is demonstrated in detail.
1. About Colloidal Silica Immobilizing Organic Acid on Surface 1-1 Regarding Immobilization of Organic Acid Colloidal silica having an organic acid immobilized on its surface functions as abrasive grains in the polishing composition. For example, the organic acid is immobilized on the surface of the colloidal silica by chemically bonding a functional group of the organic acid to the surface of the colloidal silica. If the colloidal silica and the organic acid are simply allowed to coexist, the organic acid is not fixed to the colloidal silica.

  If sulfonic acid, which is a kind of organic acid, is immobilized on colloidal silica, see, for example, “Sulphonic acid-functionalized silica through quantitative oxides of thiol groups”, Chem. Commun. 246-247 (2003). Specifically, a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane is reacted with a hydroxy group on the surface of colloidal silica to be coupled, and then the thiol group is oxidized with hydrogen peroxide. Thus, colloidal silica having sulfonic acid immobilized on the surface can be obtained.

Alternatively, if the carboxylic acid is immobilized on the surface of colloidal silica, for example, “Novel Silene Coupling Agents Containing”
a Photolabile 2-Nitrobenzyl Ester for Induction of a Carboxy Group on the Surface of Silica Gel ”, Chemistry Letters, 3, 228-229. -Colloidal silica in which carboxylic acid is immobilized on the surface can be obtained by irradiating light after reacting a silane coupling agent containing nitrobenzyl ester with a hydroxy group on the surface of colloidal silica and coupling it. .

In other cases, an organic acid such as sulfinic acid or phosphonic acid may be immobilized on the surface of colloidal silica.
Since normal colloidal silica has a zeta potential value close to zero under acidic conditions, the colloidal silica particles are not electrically repelled with each other under acidic conditions and are likely to agglomerate. In contrast, colloidal silica with an organic acid immobilized on the surface is surface-modified so that the zeta potential has a relatively large negative value even under acidic conditions. They repel each other strongly and disperse well. As a result, the storage stability of the polishing composition is improved.

1-2 Aspect Ratio The aspect ratio of colloidal silica having an organic acid immobilized on the surface is preferably less than 1.4, more preferably 1.3 or less, and 1.25 or less. Further preferred. If it does so, the surface roughness of the grinding | polishing target object resulting from the shape of an abrasive grain can be made favorable.
This aspect ratio is an average value of values obtained by dividing the length of the longest side of the smallest rectangle circumscribing the colloidal silica particles by the length of the short side of the same rectangle, and is obtained by scanning electron microscope. It can obtain | require from the image of the obtained colloidal silica particle using general image analysis software.

1-3 Average primary particle diameter The average primary particle diameter of colloidal silica having an organic acid immobilized on its surface is preferably 5 nm or more, more preferably 7 nm or more, and even more preferably 10 nm or more. . The average primary particle diameter of colloidal silica having an organic acid immobilized on the surface is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less.

If it is such a range, the grinding | polishing speed | rate of the grinding | polishing target object by polishing composition will improve. Moreover, it can suppress more that dishing arises on the surface of the grinding | polishing target object after grind | polishing using polishing composition.
In addition, the average primary particle diameter of colloidal silica is calculated based on the specific surface area of colloidal silica measured by BET method, for example.

1-4 Average secondary particle diameter The average secondary particle diameter of colloidal silica having an organic acid immobilized on its surface is preferably 25 nm or more, more preferably 30 nm or more, and preferably 35 nm or more. Further preferred. The average secondary particle diameter of colloidal silica having an organic acid immobilized on the surface is preferably 300 nm or less, more preferably 260 nm or less, and even more preferably 220 nm or less.

If it is such a range, the grinding | polishing speed | rate of the grinding | polishing target object by polishing composition will improve. Moreover, it can suppress more that a surface defect arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.
The secondary particles referred to here are particles formed by colloidal silica (primary particles) having an organic acid immobilized on the surface in the polishing composition, and the average secondary particles of the secondary particles. The diameter can be measured, for example, by a dynamic light scattering method.

1-5 Particle size distribution In the particle size distribution of colloidal silica having an organic acid immobilized on the surface, the particle diameter D90 when the accumulated particle mass from the fine particle side reaches 90% of the total particle mass, The ratio D90 / D10 with the particle diameter D10 when the accumulated particle mass reaches 10% of the total particle mass is preferably 1.5 or more, more preferably 1.8 or more. More preferably, it is 0 or more. Further, the ratio D90 / D10 is preferably 5.0 or less, and more preferably 3.0 or less.
If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve, and it can suppress more that a surface defect arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.
The particle size distribution of colloidal silica having an organic acid immobilized on the surface can be determined, for example, by a laser diffraction scattering method.

1-6 Content of Colloidal Silica The content of colloidal silica having an organic acid immobilized on its surface in the entire polishing composition is preferably 0.005% by mass or more, and more preferably 0.5% by mass or more. More preferably, it is more preferably 1% by mass or more, and particularly preferably 3% by mass or more. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve.

  Further, the content of the colloidal silica having the organic acid immobilized on the surface in the entire polishing composition is preferably 50% by mass or less, more preferably 30% by mass or less, and 20% by mass or less. More preferably. If it is such a range, the cost of polishing composition can be held down. Moreover, it can suppress more that a surface defect arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.

About the heterocyclic compound which contains a 2 or more nitrogen atom in a ring The heterocyclic compound which contains a 2 or more nitrogen atom in a ring contributes to the improvement of the grinding | polishing speed | rate of a grinding | polishing target object. In particular, it is effective for improving the polishing rate of silicon nitride. In the case where the object to be polished is silicon nitride, it is considered that when the heterocyclic compound approaches silicon nitride, the covalent bond of silicon nitride is extended and the bonding force is weakened, so that the polishing rate is improved.

  Heterocyclic compounds such as imidazole are anticorrosive agents for polishing compositions (additives that suppress deterioration of the surface condition (surface roughness, etc.) of the surface of the polishing object by suppressing dissolution of the metal on the surface of the polishing object) However, it is not known to contribute to the improvement of the polishing rate of the object to be polished. Of course, a heterocyclic compound containing two or more nitrogen atoms in the ring also functions as an anticorrosive agent in the polishing composition.

  Examples of the heterocyclic compound containing two or more nitrogen atoms in the ring include imidazole derivatives, pyrazole derivatives, triazole derivatives, tetrazole derivatives, pyrazine derivatives, pyridazine derivatives, quinoxaline derivatives, and the like. The number of ring members of this heterocyclic compound is not particularly limited, and it may be a 5-membered ring compound or a 6-membered ring compound. In one embodiment, the heterocyclic compound containing two or more nitrogen atoms in the ring is a 5-membered ring compound. Further, if the ring contains two or more nitrogen atoms, it may further contain a nitrogen atom (for example, as an amino group or a nitro group) outside the ring.

  Specific examples of the imidazole derivative include 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) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2, Examples thereof include 5-dimethylbenzimidazole, 5-methylbenzimidazole, and 5-nitrobenzimidazole.

Specific examples of the pyrazole derivative include pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazole dicarboxylic acid hydrate, 3-amino-5-phenylpyrazole, and 5-amino-3-phenylpyrazole. 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3-methylpyrazole, 1-methylpyrazole, 3-amino-5 -Methylpyrazole.
Furthermore, specific examples of the triazole derivative include 1,2,3-triazole, 1,2,4-triazole, and 1-methyl-1,2,4-triazole.
Furthermore, specific examples of tetrazole derivatives include tetrazole, 5-methyltetrazole, 5-aminotetrazole, and 5-phenyltetrazole.

These heterocyclic compounds containing two or more nitrogen atoms in the ring may be used alone or in combination of two or more.
However, among these heterocyclic compounds, imidazole, 1,2-dimethylimidazole, 2-methylimidazole, 2-aminobenzimidazole, pyrazole, 1-methylpyrazole, 3,5-dimethylpyrazole, 3,5-pyrazoledicarboxylic Acid hydrate and 3-amino-5-methylpyrazole are more preferred.

The total content of the heterocyclic compound containing two or more nitrogen atoms in the ring is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, More preferably, it is 0.10% by mass or more. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve.
In addition, the content of the heterocyclic compound containing two or more nitrogen atoms in the ring in the entire polishing composition is preferably 1.0% by mass or less, and more preferably 0.8% by mass or less. Preferably, it is 0.5 mass% or less. If it is such a range, the cost of polishing composition can be held down.

3. Liquid medium The liquid medium disperses or dissolves each component of the polishing composition (colloidal silica with an organic acid immobilized on the surface, a heterocyclic compound containing two or more nitrogen atoms in the ring, additives, etc.). It functions as a dispersion medium or solvent for the purpose. Examples of the liquid medium include water and organic solvents. One kind can be used alone, or two or more kinds can be mixed and used, but it is preferable to contain water. However, it is preferable to use water containing as little impurities as possible from the viewpoint of preventing the action of each component from being inhibited. Specifically, pure water, ultrapure water, or distilled water from which foreign substances are removed through a filter after removing impurity ions with an ion exchange resin is preferable.

4). Additives In order to improve the performance of the polishing composition, various additives such as a pH adjuster, an oxidizing agent, a complexing agent, a surfactant, a water-soluble polymer, and an antifungal agent are added. Also good.
4-1 About pH adjuster The pH value of the polishing composition is preferably 1.5 or more, and more preferably 2 or more. The higher the pH value of the polishing composition, the easier the dissolution of the polishing object. In such a range, the polishing rate of the polishing object by the polishing composition is improved. Further, since the handling becomes easier as the pH value of the polishing composition becomes lower, the pH value of the polishing composition is preferably less than 12, and more preferably 10 or less.
The pH value of the polishing composition can be adjusted by adding a pH regulator. The pH adjuster used as necessary to adjust the pH value of the polishing composition to a desired value may be either acid or alkali, and any of inorganic compounds and organic compounds. There may be.

  Specific examples of the acid as the pH adjusting agent include inorganic acids, organic acids such as carboxylic acids and organic sulfuric acids. Specific examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, phosphoric acid and the like. Specific examples of the carboxylic acid 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 and the like. Furthermore, specific examples of organic sulfuric acid include methanesulfonic acid, ethanesulfonic acid, isethionic acid and the like. These acids may be used individually by 1 type, and may be used in combination of 2 or more type.

Specific examples of the base as the pH adjusting agent include alkali metal hydroxides or salts thereof, alkaline earth metal hydroxides or salts thereof, quaternary ammonium hydroxide or salts thereof, ammonia, amines, and the like. It is done.
Specific examples of the alkali metal include potassium and sodium. Specific examples of the alkaline earth metal include calcium and strontium. Furthermore, specific examples of the salt include carbonate, hydrogen carbonate, sulfate, acetate, and the like. Furthermore, specific examples of quaternary ammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like.

The quaternary ammonium hydroxide compound includes quaternary ammonium hydroxide or a salt thereof, and specific examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide and the like.
Further, specific examples of the amine include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N- (β-aminoethyl) ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, Anhydrous piperazine, piperazine hexahydrate, 1- (2-aminoethyl) piperazine, N-methylpiperazine, guanidine and the like can be mentioned.

These bases may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these bases, ammonia, ammonium salts, alkali metal hydroxides, alkali metal salts, quaternary ammonium hydroxide compounds, and amines are preferable, and ammonia, potassium compounds, sodium hydroxide, quaternary hydroxides are more preferable. More preferred are ammonium compounds, ammonium bicarbonate, ammonium carbonate, sodium bicarbonate, and sodium carbonate.
Moreover, it is more preferable that the polishing composition contains a potassium compound as a base from the viewpoint of preventing metal contamination. Examples of the potassium compound include potassium hydroxide or potassium salt, and specific examples include potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium sulfate, potassium acetate, and potassium chloride.

4-2 Oxidizing agent An oxidizing agent may be added to the polishing composition in order to oxidize a metal to form an oxide film and facilitate polishing. Specific examples of the oxidizing agent include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchloric acid, persulfate and the like. Specific examples of the persulfate include sodium persulfate, potassium persulfate, and ammonium persulfate. These oxidizing agents may be used individually by 1 type, and may be used in combination of 2 or more type. Among these oxidizing agents, persulfate and hydrogen peroxide are preferable, and hydrogen peroxide is particularly preferable.

The greater the content of the oxidizing agent in the entire polishing composition, the higher the polishing rate of the object to be polished by the polishing composition. Therefore, the content of the oxidizing agent in the entire polishing composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. Further preferred.
Moreover, the material cost of polishing composition can be held down, so that there is little content of the oxidizing agent in the whole polishing composition. Moreover, the load of the processing of the polishing composition after polishing use, that is, the waste liquid processing can be reduced. Furthermore, excessive oxidation of the surface of the object to be polished by the oxidizing agent is less likely to occur. Therefore, the content of the oxidizing agent in the entire polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

4-3 Complexing Agent A complexing agent may be added to the polishing composition in order to improve the polishing rate of the object to be polished by the polishing composition. The complexing agent has a function of chemically etching the surface of the object to be polished. Specific examples of the complexing agent include inorganic acids or salts thereof, organic acids or salts thereof, nitrile compounds, amino acids, chelating agents and the like. These complexing agents may be used singly or in combination of two or more. These complexing agents may be commercially available products or synthetic products.

Specific examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, boric acid, tetrafluoroboric acid, hypophosphorous acid, phosphorous acid, phosphoric acid, pyrophosphoric acid and the like.
Specific examples of the organic acid include carboxylic acid and sulfonic acid. Specific examples of the carboxylic acid 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- Monovalent carboxylic acids such as heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, lactic acid, glycolic acid, glyceric acid, benzoic acid, salicylic acid, oxalic acid, malonic acid, succinic acid, glutar Examples thereof include polyvalent carboxylic acids such as acid, gluconic acid, adipic acid, pimelic acid, maleic acid, phthalic acid, fumaric acid, malic acid, tartaric acid and citric acid. Specific examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, isethionic acid and the like.

  As the complexing agent, salts of these inorganic acids or organic acids can be used, and in particular, salts of weak acid and strong base, salts of strong acid and weak base, or salts of weak acid and weak base are used. In some cases, a buffering effect on pH can be expected. Examples of such salts include potassium chloride, sodium sulfate, potassium nitrate, potassium carbonate, potassium tetrafluoroborate, potassium pyrophosphate, potassium oxalate, trisodium citrate, (+)-potassium tartrate, hexafluorophosphoric acid Examples include potassium.

Specific examples of the nitrile compound include acetonitrile, aminoacetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile, glutaronitrile, methoxyacetonitrile and the like.
Furthermore, specific examples of amino acids include glycine, α-alanine, β-alanine, N-methylglycine, N, N-dimethylglycine, 2-aminobutyric acid, norvaline, valine, leucine, norleucine, isoleucine, phenylalanine, proline, Sarcosine, ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, bicine, tricine, 3,5-diiodotyrosine, β- (3,4-dihydroxyphenyl) alanine, thyroxine, 4-hydroxyproline, cysteine, methionine , Ethionine, lanthionine, cystathionine, cystine, cysteic acid, aspartic acid, glutamic acid, S- (carboxymethyl) cysteine, 4-aminobutyric acid, asparagine, glutamine, azaserine, arginine, canavanine, cytosine Phosphorus, .delta.-hydroxylysine, creatine, histidine, 1-methylhistidine, 3-methylhistidine, tryptophan and the like.

  Furthermore, specific examples of the chelating agent include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, Transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), N- (2-carboxylateethyl) -L-aspartic acid , Β-alanine diacetate, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′— Diacetic acid, 1,2-dihydroxybenzene Such as 4,6-disulfonic acid and the like.

  Among these, at least one selected from the group consisting of an inorganic acid or a salt thereof, a carboxylic acid or a salt thereof, and a nitrile compound is preferable, from the viewpoint of the stability of the complex structure with the metal compound contained in the object to be polished. An inorganic acid or a salt thereof is more preferable. Moreover, when using what has pH adjustment function (for example, various acids) as various complexing agents mentioned above, you may utilize the said complexing agent as at least one part of a pH adjusting agent.

The lower limit value of the content of the complexing agent in the entire polishing composition is not particularly limited because the effect is exhibited even in a small amount, but the higher the content of the complexing agent, the more the polishing object by the polishing composition. Therefore, the content of the complexing agent in the entire polishing composition is preferably 0.001 g / L or more, more preferably 0.01 g / L or more, and 1 g / L. More preferably, it is the above.
Further, as the content of the complexing agent in the entire polishing composition is smaller, dissolution of the object to be polished is less likely to occur, and the step resolution is improved. Therefore, the content of the complexing agent in the entire polishing composition is preferably 20 g / L or less, more preferably 15 g / L or less, and even more preferably 10 g / L or less.

4-4 Surfactant A surfactant may be added to the polishing composition. Since the surfactant has an action of imparting hydrophilicity to the polished surface of the polished object after polishing, it can improve the cleaning efficiency of the polished object after polishing and suppress the adhesion of dirt and the like. it can. As the surfactant, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used.

  Specific examples of the anionic surfactant include polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfuric acid ester, alkyl sulfuric acid ester, polyoxyethylene alkyl sulfuric acid, alkyl sulfuric acid, alkylbenzene sulfonic acid, alkyl phosphoric acid ester, polyoxyethylene Examples thereof include ethylene alkyl phosphates, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof.

Specific examples of the cationic surfactant include alkyl trimethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, and alkyl amine salt.
Furthermore, specific examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.
Furthermore, specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, and alkylalkanolamide. can give.
These surfactants may be used individually by 1 type, and may be used in combination of 2 or more type.

As the surfactant content in the entire polishing composition increases, the cleaning efficiency of the polishing object after polishing is further improved. Therefore, the surfactant content in the entire polishing composition is 0.0001 g / L or more. It is preferable that it is 0.001 g / L or more.
Further, the smaller the surfactant content in the polishing composition as a whole, the less surfactant remains on the polished surface of the polished object after polishing, and the cleaning efficiency is further improved. The surfactant content in the whole product is preferably 10 g / L or less, and more preferably 1 g / L or less.

4-5 Water-soluble polymer A water-soluble polymer may be added to the polishing composition. When a water-soluble polymer is added to the polishing composition, the surface roughness of the polished object after polishing is further reduced (smoothed).
Specific examples of water-soluble polymers include polystyrene sulfonate, polyisoprene sulfonate, polyacrylate, polymaleic acid, polyitaconic acid, polyvinyl acetate, polyvinyl alcohol, polyglycerin, polyvinyl pyrrolidone, isoprene sulfonic acid and acrylic. Acid copolymer, polyvinylpyrrolidone polyacrylic acid copolymer, polyvinylpyrrolidone vinyl acetate copolymer, naphthalenesulfonic acid formalin condensate salt, diallylamine hydrochloride sulfur dioxide copolymer, carboxymethylcellulose, carboxymethylcellulose salt, hydroxy Examples include ethyl cellulose, hydroxypropyl cellulose, pullulan, chitosan, and chitosan salts. These water-soluble polymers may be used alone or in combination of two or more.

As the content of the water-soluble polymer in the entire polishing composition is larger, the surface roughness of the polishing surface of the object to be polished is further reduced, so that the content of the water-soluble polymer in the entire polishing composition is 0. It is preferably 0001 g / L or more, and more preferably 0.001 g / L or more.
Further, as the content of the water-soluble polymer in the entire polishing composition is smaller, the remaining amount of the water-soluble polymer on the polishing surface of the object to be polished is reduced and the cleaning efficiency is further improved. The water-soluble polymer content in is preferably 10 g / L or less, more preferably 1 g / L or less.

4-6 Antifungal Agent and Antiseptic Agent An antifungal agent and an antiseptic agent may be added to the polishing composition. Specific examples of fungicides and preservatives include isothiazoline preservatives (for example, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one), paraoxybenzoic acid Examples include esters and phenoxyethanol. One of these fungicides and preservatives may be used alone, or two or more thereof may be used in combination.

5. About the manufacturing method of polishing composition The manufacturing method of the polishing composition of this embodiment is not specifically limited, Colloidal silica which fixed the organic acid on the surface, and two or more nitrogen atoms in a ring It can manufacture by stirring and mixing the heterocyclic compound containing and various additives as needed in liquid media, such as water.
Although the temperature at the time of mixing is not specifically limited, 10 to 40 degreeC is preferable and you may heat in order to improve a dissolution rate. Further, the mixing time is not particularly limited.

6). Regarding the polishing object The type of the polishing object is not particularly limited, and examples thereof include simple silicon, silicon compounds, and metals. The simple silicon and the silicon compound are polishing objects having a layer containing a silicon-containing material.
Examples of the single silicon include single crystal silicon, polycrystalline silicon (polysilicon), and amorphous silicon. Examples of the silicon compound include silicon nitride, silicon dioxide, and silicon carbide. The silicon compound film includes a low dielectric constant film having a relative dielectric constant of 3 or less.
Furthermore, examples of the metal include tungsten, copper, aluminum, hafnium, cobalt, nickel, titanium, tantalum, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals may be contained in the form of an alloy or a metal compound. Of these metals, copper is preferred.

7). Polishing Method The configuration of the polishing apparatus is not particularly limited. For example, a holder for holding a substrate having a polishing object, a driving unit such as a motor capable of changing the rotation speed, and a polishing pad (polishing cloth) A general polishing apparatus provided with a polishing surface plate that can be attached).
As the polishing pad, a general nonwoven fabric, polyurethane, porous fluororesin, or the like can be used without particular limitation. As the polishing pad, a polishing pad that has been grooved so as to accumulate a liquid polishing composition can be used.

The polishing conditions are not particularly limited, for example, the rotational speed of the polishing platen may be a 10min ^-1 or 500 min ^-1 or less. Further, the pressure (polishing pressure) applied to the substrate having the object to be polished can be 0.7 kPa or more and 69 kPa or less.
Moreover, the method of supplying polishing composition to a polishing pad is not specifically limited, For example, the method of supplying continuously with a pump etc. is employ | adopted. The supply amount of the polishing composition is not limited, but it is preferable that the surface of the polishing pad is always covered with the polishing composition. In the polishing of the object to be polished, polishing may be performed using the stock solution of the polishing composition of the present embodiment as it is, but the polishing composition is diluted 10 times or more with a diluent such as water. Polishing may be performed using a diluted product.

After polishing, the substrate is washed with, for example, running water, and water droplets adhering to the substrate are removed by a spin dryer or the like and dried to obtain a substrate having a layer containing, for example, a silicon-containing material.
Thus, the polishing composition of this embodiment can be used for polishing a substrate. That is, the substrate can be manufactured by polishing the surface of the substrate at a high polishing rate by a method including polishing the surface of the substrate using the polishing composition of the present embodiment. Examples of the substrate include a silicon wafer having a layer containing single silicon, a silicon compound, a metal, or the like.

〔Example〕
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
Colloidal silica having sulfonic acid immobilized on the surface, various nitrogen-containing heterocyclic compounds, lactic acid as a pH adjuster, and water as a liquid medium were mixed, and Examples 1 to 9 and Comparative Example 1, 2 polishing composition was manufactured. At this time, as shown in Table 1, in Examples 1 to 9, a heterocyclic compound containing various two nitrogen atoms in the ring was used, and in Comparative Example 1, a heterocyclic compound was used. In Comparative Example 2, a heterocyclic compound (pyrrole) containing one nitrogen atom in the ring was used.

  The average primary particle diameter of colloidal silica having sulfonic acid immobilized on the surface is 32 nm in each of Examples 1 to 9 and Comparative Examples 1 and 2, and the average secondary particle diameter is 70 nm in both cases. Moreover, content in the whole polishing composition of the colloidal silica which fix | immobilized the sulfonic acid on the surface is 4 mass% in any of Examples 1-9 and Comparative Examples 1 and 2. Furthermore, the pH value of the polishing composition adjusted with the pH adjuster is 4.2 in any of Examples 1 to 9 and Comparative Examples 1 and 2. Further, the content of the heterocyclic compound in the entire polishing composition is 0 g / kg (not contained) in Comparative Example 1, and 1 g / kg (0.1% by mass) in all other cases.

Using the polishing compositions of Examples 1 to 9 and Comparative Examples 1 and 2, a wafer having a diameter of 200 mm was polished under the following polishing conditions.
Polishing machine: 200 mm wafer single-side CMP polisher Polishing pressure: 12.4 kPa
Rotating speed of polishing surface plate: 97 min ⁻¹
Carrier rotation speed: 92 min ⁻¹
Supply amount of polishing composition: 200 mL / min
Polishing time: 60 seconds

The wafers subjected to polishing are a silicon wafer with a silicon dioxide film (tetraethoxysilane film), a silicon wafer with a polycrystalline silicon film, and a silicon wafer with a silicon nitride film. In Table 1 below, a silicon wafer with a silicon dioxide film (tetraethoxysilane film) is “TEOS”, a silicon wafer with a polycrystalline silicon film is “Poly-Si”, and a silicon wafer with a silicon nitride film is “SiN”. It showed.
About each wafer, the film thickness of each film | membrane before grinding | polishing was measured using the optical interference type film thickness measuring apparatus, respectively after grinding | polishing. Then, polishing rates of silicon dioxide, polycrystalline silicon, and silicon nitride were calculated from the film thickness difference and polishing time, respectively. The results are shown in Table 1.

  From the results shown in Table 1, when polishing is performed using the polishing composition of Examples 1 to 9, the polishing rate is higher than that in the case of using the polishing composition of Comparative Examples 1 and 2 in any wafer. It can be seen that polishing can be performed. In particular, from the result of the polishing composition of Comparative Example 2, in the polishing composition containing a heterocyclic compound containing one nitrogen atom in the ring, the polishing rate is inferior compared to Examples 1 to 9, It can be seen that it is important to use a heterocyclic compound containing two or more nitrogen atoms in the ring. Moreover, it turns out that the polishing composition of Examples 1-9 has especially large polishing rate of silicon nitride compared with Comparative Examples 1 and 2.

Claims (13)

For polishing an object to be polished having a layer containing a silicon-containing material and containing colloidal silica having an organic acid immobilized on the surface and a heterocyclic compound containing two or more nitrogen atoms in the ring Composition.   The polishing composition according to claim 1, wherein the heterocyclic compound is at least one selected from imidazole derivatives and pyrazole derivatives.   The polishing composition according to claim 1, wherein the heterocyclic compound is a 5-membered ring compound.   The heterocyclic compound is imidazole, 1,2-dimethylimidazole, 2-methylimidazole, 2-aminobenzimidazole, pyrazole, 1-methylpyrazole, 3,5-dimethylpyrazole, 3,5-pyrazole dicarboxylic acid hydrate. And the polishing composition according to claim 1, which is at least one selected from 3-amino-5-methylpyrazole.   The polishing composition according to any one of claims 1 to 4, having a pH of 7 or less.   The polishing composition according to any one of claims 1 to 5, wherein the organic acid is at least one selected from sulfonic acid, carboxylic acid, sulfinic acid, and phosphonic acid.   The polishing composition according to claim 1, wherein the content of the heterocyclic compound is 0.01% by mass or more and 1% by mass or less.   The polishing composition according to claim 1, which is used for polishing silicon nitride.   The grinding | polishing method which grind | polishes a grinding | polishing target object using the polishing composition as described in any one of Claims 1-8.   The polishing method according to claim 9, wherein the polishing object is silicon nitride.   A method for producing a polishing composition according to any one of claims 1 to 8, which comprises mixing the colloidal silica, the heterocyclic compound and a liquid medium. .   The board | substrate by which the surface was grind | polished using the polishing composition as described in any one of Claims 1-8.   The board | substrate manufacturing method including grind | polishing the surface of a board | substrate using the polishing composition as described in any one of Claims 1-8.