JP2016056292A - Polishing composition and production process therefor, polishing method, and substrate and production process therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing composition that can polish a polishing object such as elemental silicon, silicon compound and metal, in particular a silicon dioxide interlayer insulating film formed by using tetra-ethoxy silane (TEOS), at high polishing speed.SOLUTION: The polishing composition contains an abrasive-grain and at least one of polyacrylic acid and polyacrylic acid derivative, and in which the electric conductivity is 2.0 mS/cm or more.SELECTED DRAWING: None

Description

  The present invention relates to a polishing composition, a manufacturing method thereof, a polishing method, a substrate, and a manufacturing method thereof.

  In a semiconductor device manufacturing process, there is a step of polishing an object to be polished such as single silicon (Si), silicon compound, metal, etc. For example, it is required to polish a metal or an interlayer insulating film at a high polishing rate. Some polishing compositions conventionally used for polishing metals and interlayer insulating films contain abrasive grains and an oxidizing agent. For example, Patent Document 1 discloses a metal polishing composition containing abrasive grains, an oxidizing agent, a protective film forming agent, an acid, and water. Patent Document 2 discloses a metal polishing composition containing an oxidizing agent and colloidal silica in which at least a part of silicon atoms on the surface is substituted with aluminum atoms. Furthermore, Patent Document 3 discloses a polishing composition containing silica having an organic acid immobilized on its surface and an oxidizing agent. However, these conventional polishing compositions do not sufficiently satisfy the user's requirements regarding the polishing rate of metals and interlayer insulating films.

JP 2009-152647 A JP 2007-207785 A JP 2013-138053 A

  Accordingly, the present invention solves the above-mentioned problems of the prior art, and a silicon dioxide interlayer insulating film formed using a polishing object such as single silicon, silicon compound, metal, etc., particularly tetraethoxysilane (TEOS). It is an object of the present invention to provide a polishing composition capable of polishing a substrate at a high polishing rate, a method for producing the same, and a polishing method.

In order to solve the above problems, a polishing composition according to one embodiment of the present invention contains abrasive grains and at least one of polyacrylic acid and a polyacrylic acid derivative, and has an electric conductivity of 2.0 mS / cm. That is the summary.
In the polishing composition according to the above aspect, the abrasive grains may contain colloidal silica having an organic acid immobilized on the surface.
Further, the polishing composition according to the above aspect may have a pH of 7 or less.
Furthermore, the polishing composition according to the above aspect may contain an electrolyte. The electrolyte may be an ammonium salt.
Furthermore, the polishing composition according to the above aspect can be used for polishing silicon dioxide.

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 dioxide.
Furthermore, a method for producing a polishing composition according to another aspect of the present invention is a method for producing a polishing composition according to the above aspect, wherein the abrasive grains and at least polyacrylic acid and a polyacrylic acid derivative are used. The gist is to include mixing one with a liquid medium.
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 polish an object to be polished such as single silicon, silicon compound, metal, etc., particularly a silicon dioxide interlayer insulating film formed using tetraethoxysilane (TEOS) at a high polishing rate. be able to. In addition, the method for producing a polishing composition of the present invention provides a polishing object such as single silicon, silicon compound, metal, etc., particularly a silicon dioxide interlayer insulating film formed using tetraethoxysilane (TEOS) at a high polishing rate. A polishing composition to be polished can be produced.

  Embodiments of the present invention will be described in detail. The polishing composition of this embodiment contains abrasive grains and at least one of polyacrylic acid and a polyacrylic acid derivative, and has an electric conductivity of 2.0 mS / cm or more. This polishing composition can be produced by mixing abrasive grains, at least one of polyacrylic acid and a polyacrylic acid derivative, and a liquid medium such as water or an organic solvent.

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. Then, it is particularly preferred to tetraethoxysilane _{(Si (OC 2 H 5)} 4) , silicon dioxide or the like is formed using a (SiO ₂₎ for polishing the interlayer insulating film. 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 dioxide at a high polishing rate.

Below, the polishing composition of this embodiment is demonstrated in detail.
1. About abrasive grains 1-1 Types of abrasive grains The types of abrasive grains are not particularly limited, and any of inorganic particles, organic particles, and organic-inorganic composite particles can be used. Specific examples of the inorganic particles include particles made of metal oxides such as silica, alumina, ceria and titania, and particles made of ceramics such as silicon nitride, silicon carbide and boron nitride. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. These abrasive grains may be used alone or in combination of two or more. Moreover, a commercial item may be used for these abrasive grains, and a synthetic item may be used. Among these abrasive grains, silica is preferable, and colloidal silica is particularly preferable.

1-2 Surface Modification Abrasive grains may be surface-modified. For example, since normal colloidal silica has a zeta potential value close to zero under acidic conditions, colloidal silica particles are not electrically repelled with each other under acidic conditions and are likely to agglomerate. On the other hand, the abrasive grains that have been surface-modified so that the zeta potential has a relatively large value even under acidic conditions, colloidal silica particles strongly repel each other and are well dispersed even under acidic conditions. As a result, the storage stability of the polishing composition is improved.

Such surface-modified abrasive grains can be obtained, for example, by doping the surface of the abrasive grains with a metal such as aluminum, titanium, zirconium, or their oxide.
Or you may perform the surface modification which fixes an organic acid to the surface of an abrasive grain. Among the surface-modified abrasive grains, colloidal silica having an organic acid immobilized on the surface is particularly preferable. 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.
Further, cationic silica (cation sol) produced by adding a basic aluminum salt or a basic zirconium salt as disclosed in JP-A-4-214022 can also be used as abrasive grains.

1-3 Aspect Ratio The aspect ratio of the abrasive grains is preferably less than 1.3, more preferably 1.25 or less, and even more preferably 1.2 or less. If it does so, it can suppress that the surface defect resulting from the shape of an abrasive grain arises on the surface of the grinding | polishing target object after grind | polishing using polishing composition.
The aspect ratio is an average value of values obtained by dividing the length of the longest side of the smallest rectangle circumscribing the abrasive grains by the length of the short side of the same rectangle. It can obtain | require using general image analysis software from the image of the obtained abrasive grain particle.

1-4 Average primary particle diameter 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 average primary particle diameter of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, and further 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 a surface defect arises on the surface of the grinding | polishing target object after grind | polishing using a polishing composition.
In addition, the average primary particle diameter of an abrasive grain is calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

1-5 About Average Secondary Particle Diameter The average secondary particle diameter of the abrasive grains is preferably 25 nm or more, more preferably 30 nm or more, and further preferably 35 nm or more. Moreover, it is preferable that the average secondary particle diameter of an abrasive grain is 300 nm or less, It is more preferable that it is 260 nm or less, It is further more preferable that it is 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 association of abrasive grains (primary particles) in the polishing composition. The average secondary particle diameter of the secondary particles is, for example, dynamic light scattering. It can be measured by the method.

1-6 Particle Size Distribution In the particle size distribution of the abrasive grains, the particle diameter D90 when the accumulated particle mass from the fine particle side reaches 90% of the total particle mass, and the accumulated particle mass from the fine particle side is the total particle mass. The ratio D90 / D10 with respect to the diameter D10 of the particles when reaching 10% is preferably 1.5 or more, more preferably 1.8 or more, and further preferably 2.0 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 the abrasive grains can be determined by, for example, a laser diffraction scattering method.

1-7 Abrasive Grain Content The abrasive grain content in the entire polishing composition is preferably 0.005% by mass or more, more preferably 0.05% by mass or more, and 0.1% The content is more preferably at least 0.5% by mass, and particularly preferably at least 0.5% by mass. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve.
The content of abrasive grains in the entire polishing composition is preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. If it is such a range, the cost of polishing composition can be held down.

2. About polyacrylic acid and polyacrylic acid derivatives Polyacrylic acid and polyacrylic acid derivatives contribute to an improvement in the polishing rate of an object to be polished. In particular, it is effective for improving the polishing rate of silicon dioxide formed using tetraethoxysilane or the like. It is considered that the polishing rate of the polishing object is improved because the abrasive grains whose mechanical action is improved by the thickening action of polyacrylic acid or polyacrylic acid derivative more effectively act on the polishing object.

One of polyacrylic acid and a polyacrylic acid derivative may be used, or both polyacrylic acid and a polyacrylic acid derivative may be used. A plurality of polyacrylic acid derivatives may be used in combination. Examples of polyacrylic acid derivatives include polyacrylic acid salts, esters and amides.
The total content of polyacrylic acid and polyacrylic acid derivative in the entire polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, and 0.001% by mass. % Or more is more preferable. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve.

The total content of polyacrylic acid and polyacrylic acid derivative in the entire polishing composition is preferably 10% by mass or less, more preferably 8% by mass or less, and 5% by mass or less. More preferably. If it is such a range, aggregation of an abrasive grain can be suppressed.
Furthermore, the mass average molecular weight of the polyacrylic acid and the polyacrylic acid derivative is preferably 500 or more, more preferably 800 or more, and even more preferably 1000 or more. If it is such a range, the grinding | polishing speed | rate of a grinding | polishing target object will improve more.

3. About electric conductivity The electric conductivity of the polishing composition needs to be 2.0 mS / cm or more. When the electrical conductivity is high, the charge double layer of the abrasive grains becomes small. For example, when the object to be polished is silicon dioxide, the electrical repulsion between the abrasive grains and the silicon dioxide is reduced, so that the polishing rate is improved. It is done.
The means for setting the electrical conductivity of the polishing composition to 2.0 mS / cm or more is not particularly limited, but means for adding an electrolyte such as salt to the polishing composition can be used. What is necessary is just to select suitably the kind and quantity of the electrolyte to add so that the electrical conductivity of polishing composition may be 2.0 mS / cm or more. The type of electrolyte is not particularly limited. For example, ammonium salts such as ammonium chloride, ammonium iodide, ammonium nitrate, ammonium sulfate, ammonium phosphate, ammonium carbonate, ammonium hydrogen carbonate, ammonium formate, and ammonium acetate should be used. Can do. Among these, ammonium nitrate and ammonium sulfate are preferable from the viewpoint of cost and handleability.

4). Liquid medium The liquid medium functions as a dispersion medium or solvent for dispersing or dissolving each component of the polishing composition (abrasive grains, at least one of polyacrylic acid and polyacrylic acid derivatives, electrolyte, additive, etc.). . 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.

5. Additives In order to improve the performance of the polishing composition, various additives such as a pH adjuster, an oxidizing agent, a complexing agent, an anticorrosive, a surfactant, a water-soluble polymer, and an antifungal agent are added. It may be added.
5-1 About pH adjuster The value of the pH 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 handling. Further, since the dissolution of the abrasive grains is less likely to occur as the pH value of the polishing composition is lowered, the pH value of the polishing composition is preferably less than 12, more preferably 7 or less. preferable.
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.

5-2 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.

5-3 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.
In addition, the smaller the content of the complexing agent in the entire polishing composition, the less the object to be polished is dissolved, and the flatness of the surface after polishing 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.

5-4 Anticorrosive Agent An anticorrosive agent may be added to the polishing composition. An anticorrosive has the effect | action which suppresses deterioration (surface roughness etc.) of the surface state of the surface of a grinding | polishing target object by suppressing melt | dissolution of the metal of the surface of a grinding | polishing target object.
Although the kind of anticorrosive agent is not particularly limited, a heterocyclic compound is preferable. Since the heterocyclic compound has high chemical or physical adsorption force to 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 in improving the flatness of the surface of the object to be polished after polishing with the polishing composition.
The number of ring members of the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having a condensed ring.

  Specific examples of the heterocyclic compound that can be used as an anticorrosive include pyrrole derivatives, pyrazole derivatives, imidazole derivatives, triazole derivatives, tetrazole derivatives, pyridine derivatives, pyrazine derivatives, pyridazine derivatives, pyridine derivatives, indolizine derivatives, indole derivatives, Indole derivatives, indazole derivatives, purine derivatives, quinolidine derivatives, quinoline derivatives, isoquinoline derivatives, naphthyridine derivatives, phthalazine derivatives, quinoxaline derivatives, quinazoline derivatives, cinnoline derivatives, buteridine derivatives, thiazole derivatives, isothiazole derivatives, oxazole derivatives, isoxazole derivatives, And nitrogen-containing heterocyclic compounds such as furazane derivatives.

  More specific examples include pyrazole derivatives such as 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, 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, 4-amino-pyrazolo [3,4-d] pyrimidine, 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.

  Examples of imidazole derivatives include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, and 5,6-dimethylbenzimidazole. 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2- (1-hydroxyethyl) benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2,5-dimethylbenzimidazole, Examples thereof include 5-methylbenzimidazole and 5-nitrobenzimidazole.

  Further, examples of triazole derivatives include 1,2,3-triazole (1H-BTA), 1,2,4-triazole, 1-methyl-1,2,4-triazole, methyl-1H-1,2, 4-triazole-3-carboxylate, 1,2,4-triazole-3-carboxylic acid, methyl 1,2,4-triazole-3-carboxylate, 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-triazole, 3-nitro-1,2,4-triazole, 3-bromo-5 Nitro , 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-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl- 1,2,4-triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro- 1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H Benzotriazole, 1- (1 ′, 2′-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) amino Methyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, and the like.

Furthermore, examples of tetrazole derivatives include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, 5-phenyltetrazole and the like.
Further, examples of indazole derivatives include 1H-indazole, 5-amino-1H-indazole, 5-nitro-1H-indazole, 5-hydroxy-1H-indazole, 6-amino-1H-indazole, 6-nitro-1H. -Indazole, 6-hydroxy-1H-indazole, 3-carboxy-5-methyl-1H-indazole and the like.

  Further, examples of indole derivatives include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, and 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-nitrile-1H-indole, 5- Nitrile-1H-indole, 6-nitrile-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 heterocyclic compounds, triazole derivatives are more preferable, and in particular, 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-methylbenzotriazole, 1,2,3-triazole, and 1,2,4 -Triazole is preferred.

In addition, these anticorrosive agents may be used individually by 1 type, and may use 2 or more types together. Moreover, as these anticorrosive agents, commercially available products or synthetic products may be used.
As the content of the anticorrosive agent in the entire polishing composition increases, dissolution of the metal on the surface of the object to be polished is suppressed, and the flatness of the surface after polishing is improved. Therefore, the content of the anticorrosive agent in the entire polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and 0.01 g / L or more. Further preferred.
Further, the smaller the content of the anticorrosive 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 anticorrosive agent in the entire polishing composition is preferably 10 g / L or less, more preferably 5 g / L or less, and even more preferably 2 g / L or less.

5-5 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 content of the surfactant in the whole product is preferably 10 g / L or less, and more preferably 5 g / L or less.

5-6 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 the water-soluble polymer include polystyrene sulfonate, polyisoprene sulfonate, polymaleic acid, polyitaconic acid, polyvinyl acetate, polyvinyl alcohol, polyglycerin, polyvinyl pyrrolidone, and a copolymer of isoprene sulfonic acid and acrylic acid. , Polyvinylpyrrolidone polyacrylic acid copolymer, polyvinylpyrrolidone vinyl acetate copolymer, naphthalenesulfonic acid formalin condensate salt, diallylamine hydrochloride sulfur dioxide copolymer, carboxymethylcellulose, carboxymethylcellulose salt, hydroxyethylcellulose, hydroxypropylcellulose , 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.
In addition, the smaller the content of the water-soluble polymer in the entire polishing composition, the smaller the amount of water-soluble polymer remaining on the polishing surface of the object to be polished. The content is preferably 10 g / L or less, and more preferably 5 g / L or less.

5-7 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.

6). About the manufacturing method of polishing composition The manufacturing method of the polishing composition of this embodiment is not specifically limited, At least one of an abrasive grain, polyacrylic acid and a polyacrylic acid derivative, electrolyte, and if desired Various additives can be produced by stirring and mixing in a liquid medium 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.

7). 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. In particular, it is suitable for polishing a silicon dioxide interlayer insulating film formed using tetraethoxysilane (TEOS).
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.

8). 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 the substrate having a layer containing silicon dioxide formed using, for example, tetraethoxysilane is obtained by removing water droplets adhering to the substrate with a spin dryer or the like and drying the substrate. can get.
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.
Abrasive grains (colloidal silica with sulfonic acid immobilized on the surface), polyacrylic acid having an average molecular weight shown in Table 1, ammonium sulfate as an electrolyte, phosphoric acid as a pH adjuster, and water as a liquid medium Were mixed to produce polishing compositions of Examples 1 to 11.
Also, abrasive grains (colloidal silica with sulfonic acid immobilized on the surface), organic compound instead of polyacrylic acid, ammonium sulfate as electrolyte, phosphoric acid as pH adjuster, and water as liquid medium are mixed. And the polishing composition of Comparative Examples 1-5 was manufactured. However, for Comparative Examples 1 and 5, an organic compound that replaces polyacrylic acid is not used. In Comparative Example 2, acrylic acid having a molecular weight of 60 is used as an organic compound that replaces polyacrylic acid. Polypropylene glycol having a weight average molecular weight of 750 was used as an organic compound instead of polyacrylic acid.

  The average primary particle diameter of colloidal silica having sulfonic acid immobilized on the surface is 32 nm in any of Examples 1 to 11 and Comparative Examples 1 to 5, and the average secondary particle diameter is 70 nm in any case. 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 1-11 and Comparative Examples 1-5. Furthermore, the pH value of the polishing composition adjusted with the pH adjuster is 3.0 in any of Examples 1 to 11 and Comparative Examples 1 to 5. Furthermore, the content of ammonium sulfate in the entire polishing composition was 0% by mass in Comparative Examples 4 and 5 (not contained), and 0.1% by mass in Example 3 and Comparative Examples 1, 2, and 3, In all other cases, the content is 0.2% by mass.

Using the polishing compositions of Examples 1 to 11 and Comparative Examples 1 to 5, a silicon wafer having a diameter of 200 mm was polished under the following polishing conditions.
Polishing device: Single-side CMP polisher for 200 mm wafers Polishing pressure: 11.0 kPa
Rotation speed of polishing surface plate: 90 min ⁻¹
Carrier rotation speed: 93 min ⁻¹
Supply amount of polishing composition: 100 mL / min
Polishing time: 60 seconds The silicon wafer subjected to polishing is a silicon wafer with a silicon dioxide film (tetraethoxysilane film). About each silicon wafer, the film thickness of the silicon dioxide film before grinding | polishing was measured, respectively using the optical interference type film thickness measuring apparatus. Then, the polishing rate of silicon dioxide was calculated from the film thickness difference and the polishing time. The results are shown in Table 1.

表１に示す結果から、実施例１〜１１の研磨用組成物を用いて研磨を行うと、比較例１〜５の研磨用組成物を用いた場合よりも高研磨速度で二酸化ケイ素の研磨を行うことができることが分かる。

From the results shown in Table 1, when polishing was performed using the polishing compositions of Examples 1 to 11, polishing of silicon dioxide was performed at a higher polishing rate than when the polishing compositions of Comparative Examples 1 to 5 were used. You can see that it can be done.

Claims (11)

  A polishing composition comprising abrasive grains and at least one of polyacrylic acid and a polyacrylic acid derivative, and having an electric conductivity of 2.0 mS / cm or more.   The polishing composition according to claim 1, wherein the abrasive grains include colloidal silica having an organic acid immobilized on the surface thereof.   The polishing composition according to claim 1 or 2, wherein the pH is 7 or less.   Polishing composition as described in any one of Claims 1-3 containing electrolyte.   The polishing composition according to claim 4, wherein the electrolyte is an ammonium salt.   The polishing composition according to any one of claims 1 to 5, which is used for polishing silicon dioxide.   The grinding | polishing method which grind | polishes a grinding | polishing target object using the polishing composition as described in any one of Claims 1-6.   The polishing method according to claim 7, wherein the polishing object is silicon dioxide.   A method for producing the polishing composition according to claim 1, wherein the abrasive grains, at least one of the polyacrylic acid and the polyacrylic acid derivative, and a liquid medium are mixed. The manufacturing method of polishing composition including doing.   The board | substrate by which the surface was grind | polished using the polishing composition as described in any one of Claims 1-6.   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 1-6.